Sample records for lvdt armature orifice

  1. Numerical Research on LVDT Sensor for Electromagnet Rigidity Measurement of Bottom Mounted CRDM

    Huh, Hyung; Lee, Jinhaeng; Cho, Yeonggarp [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)


    The stepping motor directly drives the ball screw, and the nut of the ball screw makes the electromagnet move up and down along the guide tube. At this time the higher force of an electromagnet will greatly result in less position fluctuation of the armature for a given variation of loadings. The magnetic rigidity represents one of the most important characteristics of the electromagnet. For this reason, it is necessary to measure control rod position including sagging rate due to loadings exactly. Therefore, KAERI has developed electromagnet rigidity measuring sensor using LVDT. This paper presents the case numerical research of prototyping a LVDT sensor for BMCRDM. The results of a FEM in this work lead to the following conclusions: The FEM result for LVDT shows good linearity of dIsplacement vs. induced voltage between 0[mm] and ±15[mm] intervals. For the extension of linearity interval, additional research work is necessary for the configuration and arrangement of primary and secondary coils.

  2. Design, Fabrication, and Characteristics Experiment of a Large LVDT Sensor for of Bottom Mounted CRDM

    Huh, Hyung; Lee, Jin-Haeng; Cho, Yeong-Garp; Yoo, Yeon-Sik; Ryu, Jeong-Soo [KAERI, Daejeon (Korea, Republic of)


    The stepping motor directly drives the ball screw, and the nut of the ball screw makes the electromagnet move up and down along the guide tube. At this time the higher force of an electromagnet will greatly result in less position fluctuation of the armature for a given variation of loadings. The magnetic rigidity represents one of the most important characteristics of the electromagnet. For this reason, it is necessary to measure control rod position including sagging rate due to loadings exactly. Therefore, KAERI has developed electromagnet rigidity measuring sensor using LVDT. This paper presents the case numerical and experimental research of prototyping a large LVDT sensor for BMCRDM. The FEM and experimental results for optimized large LVDT shows good linearity agreement of displacement vs. induced currents between 0[mm] and ±22[mm] intervals. The experimental result has shorter linearity interval than that of FEM result due to 100[mm] core length using experimental test. The developed FE model and analysis procedure could be useful tools for predicting the linearity of displacement of a large LVDT.

  3. Hybrid armature projectile

    Hawke, Ronald S.; Asay, James R.; Hall, Clint A.; Konrad, Carl H.; Sauve, Gerald L.; Shahinpoor, Mohsen; Susoeff, Allan R.


    A projectile for a railgun that uses a hybrid armature and provides a seed block around part of the outer surface of the projectile to seed the hybrid plasma brush. In addition, the hybrid armature is continuously vaporized to replenish plasma in a plasma armature to provide a tandem armature and provides a unique ridge and groove to reduce plasama blowby.

  4. Method and apparatus for calibrating a linear variable differential transformer

    Pokrywka, Robert J.


    A calibration apparatus for calibrating a linear variable differential transformer (LVDT) having an armature positioned in au LVDT armature orifice, and the armature able to move along an axis of movement. The calibration apparatus includes a heating mechanism with an internal chamber, a temperature measuring mechanism for measuring the temperature of the LVDT, a fixture mechanism with an internal chamber for at least partially accepting the LVDT and for securing the LVDT within the heating mechanism internal chamber, a moving mechanism for moving the armature, a position measurement mechanism for measuring the position of the armature, and an output voltage measurement mechanism. A method for calibrating an LVDT, including the steps of: powering the LVDT; heating the LVDT to a desired temperature; measuring the position of the armature with respect to the armature orifice; and measuring the output voltage of the LVDT.

  5. Signal conditioner for LVDT displacement sensors

    Blejan, Marian; Ilie, Ioana; Comes, Mircea; Lupu, Bogdan


    The paper describes a systematic approach regarding the development of a linear position and speed transducer used in hydraulic applications. The electronic module of the transducer is integrated into the LVDT sensor body, to obtain an assembly capable to operate into hydraulic specific environment conditions: vibrations, wide range of operating temperature and high humidity with condensation, significant mechanic and hydraulic shocks, important electromagnetic interference with the intense electric current circuits specific for hydraulic equipment a.o. To obtain the functioning and precision performances needed, it was assessed the use of a reduced number of small size electronic components. It was chosen an original solution for excitation and processing of the signal from the sensor that allows the direct connection of the sensor with the microcontroller used into the electronic module of the transducer. The power supply of the transducer was implemented throughout commutation (buck-converter) providing a superior efficiency and reducing the risk of overheating the electronic module by Joule effect. The performances determined by experiment confirms the designing data by meaning to obtain the position indication of 10000 of stabile divisions and the speed indication of 1000 stabile divisions; the process time of the electronic module is 40ms.

  6. Ironless armature torque motor

    Fisher, R. L.


    Four iron-less armature torque motors, four Hall device position sensor assemblies, and two test fixtures were fabricated. The design approach utilized samarium cobalt permanent magnets, a large airgap, and a three-phase winding in a stationary ironless armature. Hall devices were employed to sense rotor position. An ironless armature torque motor having an outer diameter of 4.25 inches was developed to produce a torque constant of 65 ounce-inches per ampere with a resistance of 20.5 ohms. The total weight, including structural elements, was 1.58 pounds. Test results indicated that all specifications were met except for generated voltage waveform. It is recommended that investigations be made concerning the generated voltage waveform to determine if it may be improved.

  7. A high precision radiation-tolerant LVDT conditioning module

    Masi, A; Losito, R; Peronnard, P; Secondo, R; Spiezia, G


    Linear variable differential transformer (LVDT) position sensors are widely used in particle accelerators and nuclear plants, thanks to their properties of contact-less sensing, radiation tolerance, infinite resolution, good linearity and cost efficiency. Many applications require high reading accuracy, even in environments with high radiation levels, where the conditioning electronics must be located several hundred meters away from the sensor. Sometimes even at long distances the conditioning module is still exposed to ionizing radiation. Standard off-the-shelf electronic conditioning modules offer limited performances in terms of reading accuracy and long term stability already with short cables. A radiation tolerant stand-alone LVDT conditioning module has been developed using Commercial Off-The-Shelf (COTS) components. The reading of the sensor output voltages is based on a sine-fit algorithm digitally implemented on an FPGA ensuring few micrometers reading accuracy even with low signal-to-noise ratios. ...

  8. In-Flight Armature Diagnostics

    Allison, Stephen W [ORNL; Cates, Michael R [ORNL; Goedeke, Shawn [ORNL


    A feasibility demonstration is reported for a method of determining instantaneous temperature and velocity of an armature in flight. Instantaneous diagnostics such as this could be critical for achieving further improvements in railgun operation. Such activity has the potential to enable design enhancements by providing information on the state of the armature and its relationship to the rail as it proceeds down the bore. The method exploits the temperature dependence of fluorescence from a phosphor coating applied to the armature. The demonstration used both a very small-scale portable railgun and a small-scale benchtop railgun. For these tests, the output of a pulsed ultraviolet (UV) laser is delivered by optical fiber through an access port drilled into the insulator between the rails. As the armature passes, the UV light illuminates a small area of phosphor on the armature. The phosphor fluoresces and decays at a rate dependent on the temperature of the phosphor. A second optical fiber in close proximity collects the fluorescence and conveys it to a detector and associated data acquisition system. Temperature is determined from a measurement of the decay time. To provide for velocity measurement on the small-scale railgun, light from a red diode laser, delivered by fiber probe inserted into the bore, produced distinctive reflections at the leading and trailing edges of the armature as it passed. Also, two grooves cut into the armature produced fiducial pulses that enabled velocity measurement.

  9. A measurement of a control rod drop using an LVDT

    Choi, Myoung-Hwan; Kim, Ji-Ho; Huh, Hyung; Yu, Je-Yong; Sohn, Dong-Seong


    A control element drive mechanism is a reactor regulating system, which is to insert, withdraw, or maintain a control rod containing neutron-absorbing material within a reactor core to control the reactivity of the reactor. The ball-screw type CEDM for the small and medium research reactor has a spring-hydraulic damper to reduce the impact force due to the free drop of the CEDM. This paper describes the experimental results to obtain the drop characteristics of the CEDM. The tests are performed by using a full-scale structure except the control element assembly, and a drop time and displacement after an impact are measured by using an LVDT. The influences of the rod weight and the drop height on the drop behavior are also estimated on the basis of test results. In case of the longest stroke, the drop time of the control rod is within 4.5 seconds to meet the design requirement. The behavior after the impact shows a general damping motion of the spring-damper system, and the maximum displacement is measured as 15.6 mm.

  10. Feasibility of intercalated graphite railgun armatures

    Gaier, James R.; Gooden, Clarence E.; Yashan, Doreen; Naud, Steven


    Graphite intercalation compounds may provide an excellent material for the fabrication of electro-magnetic railgun armatures. As a pulse of power is fed into the armature the intercalate could be excited into the plasma state around the edges of the armature, while the bulk of the current would be carried through the graphite block. Such an armature would have the desirable characteristics of both diffuse plasma armatures and bulk conduction armatures. In addition, the highly anisotropic nature of these materials could enable the electrical and thermal conductivity to be tailored to meet the specific requirements of electromagnetic railgun armatures. Preliminary investigations were performed in an attempt to determine the feasibility of using graphite intercalation compounds as railgun armatures. Issues of fabrication, resistivity, stability, and electrical current spreading are addressed for the case of highly oriented pyrolytic graphite.

  11. Ironless-armature brushless motor

    Fisher, R. L.


    Device uses 12-pole samarium cobalt permanent-magnet rotor and three Hall-effect sensors for commutation. In prototype motor, torque constant (3-phase delta) is 65 oz-in/amp; electrical time constant (L/R) is 0.2 x 0.001 sec, and armature resistance is 20 ohms.

  12. Selection of Soft Magnetic Core Materials Used on an LVDT Prototype

    R. Yañez-Valdez


    Full Text Available Traditionally, the use of ferrite as a core of the linear variable differential transformer (LVDT is suggested in its designs. Nevertheless, problems related to its brittleness and low tensile strength may be considered as important drawbacks for its use as a core material, especially when its geometry is likely to be modified. This work explores other alternatives related to soft magnetic materials, less used in applications of an LVDT core. By means of a decision matrix, from an assortment of different materials, three alternatives were selected. This proposal provides the identification of those materials with higher qualification values to be used as core material. In order to validate the performance of the selected materials, a prototype of LVDT was designed and fabricated. The design was carried out taking into consideration typical performance specifications. Finally, a comparison of the measurements of sensitivity and linearity of the proposed and traditional materials was made.

  13. An ironless armature brushless torque motor

    Studer, P. A.


    A high torque motor with improved servo mechanism is reported. Armature windings are cast into an epoxy cylinder and armature conductors are integrally cast with an aluminum mounting ring which provides thermal conductance directly into the structure. This configuration eliminates magnetic hysteresis because there is no relative motion between the rotating magnetic field and any stationary iron. The absence of destabilization forces provides a fast electrical response compared with a typical torquer of conventional construction.

  14. The preliminary feasibility of intercalated graphite railgun armatures

    Gaier, James R.; Gooden, Clarence E.; Yashan, Doreen; Naud, Steve


    Graphite intercalation compounds may provide an excellent material for the fabrication of electromagnetic railgun armatures. As a pulse of power is fed into the armature the intercalate could be excited into the plasma state around the edges of the armature, while the bulk of the current would be carried through the graphite block. Such an armature would have both diffuse plasma armatures and bulk conduction armatures. In addition, the highly anisotropic nature of these materials could enable the electrical and thermal conductivity to be tailored to meet the specific requirements of electromagnetic railgun armatures. Preliminary investigations have been performed in an attempt to determine the feasibility of using graphite intercalation compounds as railgun armatures. Issues of fabrication, resistivity, stability, and electrical current spreading have been addressed for the case of highly oriented pyrolytic graphite.

  15. The preliminary feasibility of intercalated graphite railgun armatures

    Gaier, James R.; Gooden, Clarence E.; Yashan, Doreen; Naud, Steve


    Graphite intercalation compounds may provide an excellent material for the fabrication of electromagnetic railgun armatures. As a pulse of power is fed into the armature the intercalate could be excited into the plasma state around the edges of the armature, while the bulk of the current would be carried through the graphite block. Such an armature would have both diffuse plasma armatures and bulk conduction armatures. In addition, the highly anisotropic nature of these materials could enable the electrical and thermal conductivity to be tailored to meet the specific requirements of electromagnetic railgun armatures. Preliminary investigations have been performed in an attempt to determine the feasibility of using graphite intercalation compounds as railgun armatures. Issues of fabrication, resistivity, stability, and electrical current spreading have been addressed for the case of highly oriented pyrolytic graphite.

  16. In situ stress measurement with the new LVDT - Cell - method description and verification

    Hakala, M. [KMS Hakala Oy, Nokia (Finland); Christiansson, R. [Svensk Kaernbraenslehantering AB, Stockholm (Sweden); Martin, D. [Univ. of Alberta, Edmonton (Canada); Siren, T.; Kemppainen, K.


    Posiva Oy and SKB (Svensk Kaernbraenslehantering AB) tested the suitability a new LVDT-cell (Linear Variable Differential Transducer cell) to measure the induced stresses in the vicinity of an excavated surface and further to use these results to interpret the in situ state of stress. It utilises the overcoring methodology, measuring the radial convergence of four diameters using eight LVDTs, and is similar in concept to the USBM-gauge. A 127 mm diameter pilot-hole is required and the overcore diameter is 200 mm. The minimum overcoring length is 350 mm, and hence a compact drill can be utilised. Extensive testing of the LVDT-cell shows it to be robust and suitable for use in an underground environment. Sensitivity tests also show that the cell can withstand a range of operating conditions and still provide acceptable results. The in situ stress at the measurement location can be solved by numerical inversion using the results of at least three overcoring measurements around the three-dimensional tunnel section. The large dimensions of the measurement tool and the ability to utilise multiple measurements at various locations in a tunnel section, provides flexibility in selecting an appropriate rock mass volume. Because the inversion technique relies on knowing the exact location of the measurements and the geometry profile of the tunnel, modern survey techniques such as Lidar or photogrammetric technology should be used. Checks using traditional surveying techniques should also be used to ensure adequate survey resolution, specially in case of sidecoring measurements. To evaluate the suitability of the LVDT-cell to provide the in situ state of stress, tests were carried out in the drill-and-blast TASS tunnel and TBM tunnel at the Aespoe Hard Rock Laboratory in Sweden. The state of stress established using the LVDT-cell was in agreement with the state of stress established previously using traditional overcoring and hydraulic fracturing methods. In this study, the

  17. The linear variable differential transformer (LVDT) position sensor for gravitational wave interferometer low-frequency controls

    Tariq, H; Vetrano, F; Wang Chen Yang; Bertolini, A; Calamai, G; DeSalvo, R; Gennai, A; Holloway, L E; Losurdo, G; Marka, S; Mazzoni, M; Paoletti, F; Passuello, D; Sannibale, V; Stanga, R


    Low-power, ultra-high-vacuum compatible, non-contacting position sensors with nanometer resolution and centimeter dynamic range have been developed, built and tested. They have been designed at Virgo as the sensors for low-frequency modal damping of Seismic Attenuation System chains in Gravitational Wave interferometers and sub-micron absolute mirror positioning. One type of these linear variable differential transformers (LVDTs) has been designed to be also insensitive to transversal displacement thus allowing 3D movement of the sensor head while still precisely reading its position along the sensitivity axis. A second LVDT geometry has been designed to measure the displacement of the vertical seismic attenuation filters from their nominal position. Unlike the commercial LVDTs, mostly based on magnetic cores, the LVDTs described here exert no force on the measured structure.

  18. Precise individualized armature for ear reconstruction

    Evenhouse, Raymond J.; Chen, Xiaoming


    The cosmetic result of an ear restored surgically or via prosthetics is dependent on the surgeon''s ability to carve a precise cartilage armature at the time of surgery or the prosthetist''s ability to sculpt in wax an exact duplicate of the patient''s " missing" ear. Introducing CAD/CAM technology into the process benefits the esthetic outcome of these procedures. By utilizing serial section information derived from CAT MRI or moulage techniques a mirrorimage of the patient''s " donor" ear is generated. The resulting earform data is then used for the design of a cartilage armature produced by multi-axis milling or to produce by stereolithography a model which serves as the basis for a prosthesis.

  19. The study of sliding contact in railgun with metal armature

    Kondratenko, A.K.; Bykov, M.A.; Schastnykh, B.S.; Glinov, A.P.; Poltanov, A.E. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation)


    An experimental technique for the study of the current distribution in the rails and a moving metal armature is developed. The work was carried out on a special experimental railgun with a capacitor power supply. The set of small dB/dt probes as well as wire contact probes were arranged in close vicinity of the rail and armature contact surface. For interpretation of dB/dt measurements the computation technique and program of restoration of current density distribution along the armature was developed. The size and the location of the current concentration zone in the contact area are obtained for several combinations of rail and armature materials; bronze and copper rails, Al and Ti alloy armature. A stationary armature tests with resistive stainless steel and graphite layers were also made to estimate the influence of the layer material resistivity on the current distribution.

  20. Structure and function of the cibarial armature in Simuliidae.

    Reid, G D


    Cibarial armature morphology in adult female blackflies (Diptera: Simuliidae) is described using scanning electron microscopy. Three distinct types of armature are recognized, comprising those with teeth, e.g. Simulium ochraceum, S. ornatum, S. veracruzanum and S. vorax, those with spicules, e.g. Austrosimulium bancrofti, S. damnosum, S. exiguum, S. metallicum and S. neavei; and those lacking these projections, e.g. Prosimulium rufipes and S. lineatum. Whereas the armature is poorly developed in vectors of human onchocerciasis such as S. damnosum, S. exiguum, S. metallicum and S. neavei, the well-developed armature in S. ochraceum, S. veracruzanum and S. vorax does not prevent these species becoming infected with Onchocerca spp. (Nematoda: Onchocercidae). Hence the armature is not primarily a mechanism to counteract microfilaria superinfection. Since cibarial armatures are more developed in the haematophagous females than in the males of certain Families of flies, e.g. Ceratopogonidae, Culicidae, Phlebotominae and Simuliidae in the sub-order Nematocera, evidently the armature has evolved in response to the blood-feeding habit. As the suction of imbibed blood by the cibarial pump may require a valve mechanism to prevent back-flow, it is suggested that the armature is primarily for this purpose. Secondarily, the cibarial armature presents a damaging barrier against ingested microfilariae.

  1. Experimental measurement of ablation effects in plasma armature railguns

    Parker, J.V.; Parsons, W.M.


    Experimental evidence supporting the importance of ablation in plasma armature railguns is presented. Experiments conducted using the HYVAX and MIDI-2 railguns are described. Several indirect effects of ablation are identified from the experimental results. An improved ablation model of plasma armature dynamics is proposed which incorporates the restrike process.

  2. Residual magnetism holds solenoid armature in desired position

    Crawford, R. P.


    Holding solenoid uses residual magnetism to hold its armature in a desired position after excitation current is removed from the coil. Although no electrical power or mechanical devices are used, the solenoid has a low tolerance to armature displacement from the equilibrium position.

  3. Experimental Study on the Expansion Uniformity of Armature

    HE Yuan-hang; WU Bi; MA Yue-fen; ZHANG Qing-ming


    A measurement system has been developed based on high-precision printed probes in printed circuit board (PCB) and steep rising-time probe adapters,which can be applied to study the expansion uniformity of armature in a helical magnetic flux compression generator (HFCG).The influences of wall thickness and initiation position on the expansion uniformity of armature in HFCG were experimentally investigated.The results show that the armature with thinner wall thickness will easily rupture due to the high pressure of detonation products inside,the armature with larger wall thickness will easily crack due to the tensile stress on the outer surface of the wall,the influence of the end effect on the expansion uniformity can be ignored if the distance between the first group of probe and the initiation point is more than 3 times the armature diameter.

  4. Influence of the armature-rail geometry on results of launch experiments of fibre armatures with railguns

    Karthaus, W.; Huijser, T.; Kolkert, W.J.


    To increase the transition velocity of solid fibre brush armatures, launch experiments have been performed with an increased armature height of about 15 %. However, results of experiments under equal launch conditions did not show higher transition velocities up till now. In order to find an explana

  5. Orifice plates and venturi tubes

    Reader-Harris, Michael


    This book gives the background to differential-pressure flow measurement and goes through the requirements explaining the reason for them. For those who want to use an orifice plate or a Venturi tube the standard ISO 5167 and its associated Technical Reports give the instructions required.  However, they rarely tell the users why they should follow certain instructions.  This book helps users of the ISO standards for orifice plates and Venturi tubes to understand the reasons why the standards are as they are, to apply them effectively, and to understand the consequences of deviations from the standards.

  6. dynamics of armature acceleration in a railgun channel

    Gendel, Yu. G.; Glushkov, I. S.; Kareev, Yu. A.; Nikolashin, A. A.; Novikov, V. P.; Halimullin, Yu. A.


    We have analyzed the results of experiments on the acceleration of an aluminum armature with a mass of about 3 g in a railgun with steel rails. The experiment was aimed at studying processes in a high-velocity contact at a velocity close to the transition value related to the contact velocity skin effect. In the absence of high-current arcs, a velocity of 1.2 km/s has been reached with the aid of armature pressing to the rails. A retarding force that acts upon the armature that moves in the railgun channel has been determined.

  7. Armatures in thermal power plants; Armaturen in Waermekraftwerken

    Wiesner, Thomas; Moenning, Wolfgang (eds.)


    The book includes contributions on the following issues: (1) Fundamentals: Stop valves - minimal power loss due to full transmission. Safety valves - reliable overpressure protection. Indispensible feature of thermal power plant safety systems: the turbine bypass station. Condensate drain - safe discharge of harmful condensate. Safety armatures for gas consumption facilities. Electric actuators - automation of almost all armatures in power plants. (2) Case studies: Drainage armatures for power plant use. Steam cooling and saturation in thermal power plants - established techniques and solutions. Isolation flap for cooling water systems. Regulatory requirements and their practical implementation.

  8. Performance Characteristics of an Armature Voltage Controlled D.C. ...

    Performance Characteristics of an Armature Voltage Controlled D.C. Motor. ... the performance characteristics of a test motor are obtained by digital computer analysis. ... speed regulation and response characteristics for the d. c. drive system.

  9. Solid-armature railguns without the velocity-skin effect

    Cowan, M.


    If the velocity-skin effect could be eliminated, solid-armature railguns might reach high velocity ({ge} 6 km/s) without forcing most of the armature current to pass through an arc. Even then, magnetic diffusion (the ``normal`` skin effect) will limit acceleration. In this paper, the performance limits for railguns which are free from the velocity-skin effect are investigated by deriving the upper limits for a specific kind of power supply. Previous performance estimates made for solid-armature railguns are examined in the light of these results and are found to be relatively very optimistic. A railgun design which limits the velocity-skin effect and which may allow improved performance for solid armatures is described. 6 refs.

  10. Brushless direct-current motor with stationary armature and field

    Studer, P. A.


    Electronically commutated dc motor has an active fixed field winding, and active fixed armature winding, and passive rotor. By use of brushless dc motor switching technique, motor provides continuous controllable and reversible torque without use of sliding contacts.

  11. A Simple Model for Simulation of Armature Expanding Process

    杨显俊; 董志伟


    We propose a scheme to simulate the dynamic process of the armature expansion of explosive magnetic flux compression generators. Values of the deflective angle and the velocity of expanding the innermost radius of copper cylinder (or armature) caused by explosives detonation are calculated, which are in good agreement with the experimental data. The calculated results show that there may be some dynamic processes that exist during explosive detonation.

  12. Temperature estimates for a railgun plasma armature

    Kowalenko, Victor [School of Physics, University of Melbourne, VIC (Australia); Clark, Gregory A


    A free-flowing plasma in a railgun refers to a plasma which is not impeded by a projectile during a firing. One advantage in performing experiments with such plasmas is that spectroscopic measurements can be made when they are ejected. In this paper we analyse absorption and emission spectra of a free-flowing plasma for wavelengths between 300 and 625 nm in several firings. Calculations of the degree of ionization for the various species identified on the spectra are used to produce an estimate for the temperature of a free-flowing plasma in a RAPID railgun that lies between 11x10{sup 3} and 25x10{sup 3} K. This temperature range is reduced to 11x10{sup 3} K by using a special computer code that predicts the thermochemical functions and transport coefficients of partially- and fully-ionized plasmas. The code is then used to develop temperature estimates of the plasma armature in railgun firings with projectiles. For these plasmas, which are expected to be denser than free-flowing plasmas, a temperature estimate of 14x10{sup 3} K is obtained for a RAPID railgun firing at shot-out. (author)

  13. Hollow Cathode With Multiple Radial Orifices

    Brophy, John R.


    Improved hollow cathode serving as source of electrons has multiple radial orifices instead of single axial orifice. Distributes ion current more smoothly, over larger area. Prototype of high-current cathodes for ion engines in spacecraft. On Earth, cathodes used in large-diameter ion sources for industrial processing of materials. Radial orientation of orifices in new design causes current to be dispersed radially in vicinity of cathode. Advantageous where desireable to produce plasma more nearly uniform over wider region around cathode.

  14. Magnetic Flux Compression Experiments Using Plasma Armatures

    Turner, M. W.; Hawk, C. W.; Litchford, R. J.


    Magnetic flux compression reaction chambers offer considerable promise for controlling the plasma flow associated with various micronuclear/chemical pulse propulsion and power schemes, primarily because they avoid thermalization with wall structures and permit multicycle operation modes. The major physical effects of concern are the diffusion of magnetic flux into the rapidly expanding plasma cloud and the development of Rayleigh-Taylor instabilities at the plasma surface, both of which can severely degrade reactor efficiency and lead to plasma-wall impact. A physical parameter of critical importance to these underlying magnetohydrodynamic (MHD) processes is the magnetic Reynolds number (R(sub m), the value of which depends upon the product of plasma electrical conductivity and velocity. Efficient flux compression requires R(sub m) less than 1, and a thorough understanding of MHD phenomena at high magnetic Reynolds numbers is essential to the reliable design and operation of practical reactors. As a means of improving this understanding, a simplified laboratory experiment has been constructed in which the plasma jet ejected from an ablative pulse plasma gun is used to investigate plasma armature interaction with magnetic fields. As a prelude to intensive study, exploratory experiments were carried out to quantify the magnetic Reynolds number characteristics of the plasma jet source. Jet velocity was deduced from time-of-flight measurements using optical probes, and electrical conductivity was measured using an inductive probing technique. Using air at 27-inHg vacuum, measured velocities approached 4.5 km/s and measured conductivities were in the range of 30 to 40 kS/m.

  15. A technique to reduce plasma armature formation voltage

    Jamison, K.A. (Science Applications International Corp., Shalimar, FL (US)); Littrell, D.M. (Air Force Armament Lab., Eglin AFB, FL (United States))


    The initiation of a plasma armature by foil vaporization in a railgun is often accompanied by a large, fast, voltage transient appearing on both the breech and muzzle of the gun. For a railgun driven by an inductor/opening switch power supply, this voltage transient becomes a concern during current commutation from the switch to the railgun. To lessen the requirements on the opening switch, techniques must be found to reduce the armature formation voltage. This paper presents the experimental results from railgun firings at AFATL's Electromagnetic Launcher Basic Research Facility (Site A-15, Eglin Air Force Base, Florida) using different shapes of initiation foils. These foils have been designed to vaporize into a plasma armature with reduced transient voltages. A design criteria was developed to ensure that all portions of the foil vaporize at slightly different times.

  16. Method and apparatus for monitoring armature position in direct-current solenoids

    Moyers, J.C.; Haynes, H.D.


    A method for determining the position of an armature of a dc-powered solenoid is disclosed. Electrical circuitry is provided to introduce a small alternating current flow through the coil. As a result, the impedance and resistance of the solenoid coil can be measured to provide information indicative of the armature`s position. 5 figs.

  17. Method and apparatus for monitoring armature position in direct-current solenoids

    Moyers, J.C.; Haynes, H.D.


    A method for determining the position of an armature of a dc-powered solenoid is disclosed. Electrical circuitry is provided to introduce a small alternating current flow through the coil. As a result, the impedance and resistance of the solenoid coil can be measured to provide information indicative of the armature`s position. 5 figs.

  18. Method of analyzing vibration characteristics of armature system of hermetically sealed electromagnetic relay

    REN Wan-bin; CUI Li; LUO Fu-biao; ZHAI Guo-fu


    Published research is minimal on vibration characteristics of hermetically sealed electromagnetic relay (EMR) exposed to mechanical environment. The vibration characteristics of armature system, link contact system with electromagnetic system will cause EMR malfunction. The nonlinear dynamics model of armature systems was studied by considering electromagnetic attraction force and opposite mechanical force in this paper. Angular displacements of armature under different sinusoidal vibration conditions are solved in order to obtain the failure mode result from armature system. Vibration tests showed the presented analyzing method is suitable for EMR. The conclusions are instructive for increasing vibration resistance of armature systems of EMR, and are significant for reliability design of switch apparatus.


    Allison, Stephen W [ORNL; Cates, Michael R [ORNL; Goedeke, Shawn [ORNL; Crawford, M. T. [Institute for Advanced Technology, Austin, TX; Ferraro, S. B. [Institute for Advanced Technology, Austin, TX; Akerman, A. [Diditco, Inc., Knoxville


    This test established feasibility for 'on the fly' temperature measurements of rail gun projectiles. In addition, an approach for projectile velocity measurement was also demonstrated. Insight was gained into other useful optical and fiberoptic diagnostic approaches. Instantaneous diagnostics could be critical for achieving further improvements in rail gun operation. They have the potential to enable design enhancements by providing information on the state of the armature and its relationship to the rail as it proceeds down the bore. To that end, the following was accomplished: (1) Optical fibers successfully delivered optical excitation and returned reflective and fluorescence signals as desired. (2) Luminescent coatings survived multiple firings--approximately 40 shots. (3) Optical triggering effectively synchronized an ultraviolet laser pulse to strike the moving armature. (4) Velocity measurements were successfully accomplished by either triggering on the armature front edge using two red diode lasers or by using a single laser and grooved marks a known distance apart on the armature surface. (5) Velocities ranged from 19 to 88 m/s. (6) Temperatures of 30 to 92 C were measured with a precision of about 2 C-: (a) This precision was achieved with a single laser shot and (b) Motion effect was observed but a methodology adequately corrected the result. The correction was only about 2 C. (7) Adequate signal-to-noise and measurement precision was achieved with a single laser shot.

  20. Armature reaction effects on HTS field winding in HTS machine

    Mijatovic, Nenad; Jensen, Bogi Bech


    This paper presents experimental results from the Superwind laboratory setup. Particular focus in the paper has been placed on describing and quantifying the in influence of armature reaction on performance of the HTS fled winding. Presented experimental results have confrmed the HTS feld winding...

  1. Nonlinear Distortion Mechanisms and Efficiency of Balanced-Armature Loudspeakers

    Jensen, Joe

    ) and the linearity of the magnetic material is therefore of great importance. This thesis describes the inherent nonlinear parameters of the balanced-armature loudspeaker and demonstrates how the nonlinearity of these parameters may be reduced by design. A sim- ple technique for incorporating magnetic leakage...... and to validate simpler equivalent circuit models. A large scale model of a balanced-armature loudspeaker has been developed and its inherent nonlinear parameters have been measured and compared to the theoretically predicted values. A measurement setup for determining the magnetic properties of soft magnetic...... materials has also been developed, since it is of great importance to understand what kind of linear and nonlinear transformations the magnetic materials impose on the signal. In hearing aid applications the power efficiency of the loudspeaker is important because every reduction in power consumption...

  2. Ac Synchronous Servo Based On The Armature Voltage Prediction Model

    Hoshino, Akihiro; Kuromaru, Hiroshi; Kobayashi, Shinichi


    A new control method of the AC synchro-nous servo-system (Brushless DC servo-system) is discussed. The new system is based on the armature voltage prediction model. Without a resolver-digital-conver-ter nor a tachometer-generator, the resolver provides following three signals to the system immediately, they are the current command, the induced voltage, and the rotor speed. The new method realizes a simple hardware configuration. Experimental results show a good performance of the system.

  3. Ablation and geometry change study of solid armature in a railgun

    Zhang, Ya-Dong; Ruan, Jiang-Jun; Hu, Yuan-Chao; Gong, Ruo-Han; Wen, Wu


    Armature plays an important role in the electromagnetic launch process. Due to the skin effect, the current density distribution is neither uniform on the rail, nor on the armature. High current density centralization in one part could lead to a partial high temperature and make the armature material melt down and be ablated, especially at low velocity. In this paper we try to change the geometry of a Cshaped armature to improve the current density distribution and reduce the ablation. Four variants of C-shaped armatures are designed to study the specific features, including a conventional C-shaped armature (CCA), a rounded leading edge C-shaped armature (LCA), a rounded trailing edge C-shaped armature (TCA), and a rounded incorporate edge C-shaped armature (ICA). A novel low-speed experiment is constructed and tested. The armatures are ablated and recovered to compare the improved effects. Then finite element simulations according to the experimental results are performed to further analyze the experimental results. It is proved that the current density and hence the temperature distribution can be immensely improved by simply changing the armature geometry. LCA and ICA show that the erosion is more uniform on the contact surface due to the rounded leading edge. The curved trailing edge could improve the uniformity of the current on the interface. ICA which combines the effects of LCA and TCA is the best option in the four armatures. How much the leading edge and the trailing edge should be curved involves the geometry of CCA and the posture of the interface on the rail. A saddle shape is a good option to improve the current density and temperature distribution in the throat. Erosion mechanism is analyzed finally. The experiments and simulations support the erosion and transition mechanism. A detailed description of the experiments and simulations is also presented in this paper.

  4. Double orifice mitral valve: A case report

    Musić Ljilja


    Full Text Available Introduction. Double orifice mitrol valve (DOMV is a very rare congenital heart defect. Case report. We reported 20-year-old male referred to our center due to evaluation of his cardiologic status. He was operated on shortly after birth for a tracheoesophageal fistula. Accidentally, echocardiography examination at the age of 4 years revealed double orifice mitral valve (DOMV without the presence of mitral regurgitation, as well as mitral stenosis, with normal dimensions of all cardiac chambers. The patient was asymptomatic, even more he was a kick boxer. His physical finding was normal. Electrocardiography showed regular sinus rhythm, incomplete right bundle branch block. Transthoracic echocardiography (TTE examination revealed the normal size of the left atrial, mitral leaflets were slightly more redundant. The left and right heart chambers, aorta, tricuspid valve and pulmonary artery valve were normal. During TTE examination on a short axis view two asymmetric mitral orifices were seen as a double mitral orifice through which we registered normal flow, without regurgitation and mitral stenosis. Transesophageal echocardiography (TEE examination from the transgastric view at the level of mitral valve, showed 2 single asymmetric mitral orifices separated by fibrous tissue, mitral leaflet with a separate insertion of hordes for each orifice. Conclusion. The presented patient with DOMV is the only one recognized in our country. The case is interesting because during 16-year a follow-up period there were no functional changes despite the fact that he performed very demanded sport activities. This is very important because there is no information in the literature about that.

  5. On the attached length of orifices

    Komkin, A. I.; Mironov, M. A.; Yudin, S. I.


    The attached length of orifices in reactive mufflers has been estimated based on numerical calculations by the finite-element method. The numerical results for a diaphragm in a duct are compared with the theoretical data obtained by Rayleigh, Fock, Karal, and Ingard. The dependence of the attached length on the diaphragm thickness is given. The results obtained are generalized for the case in which the orifice is a Helmholtz resonator neck. The effect of the resonator length on the attached length of the neck is analyzed.

  6. Research for diagnosing electronic control fault of astronomical telescope's armature winding by step signal

    Zhang, Yulong; Yang, Shihai; Gu, Bozhong


    This paper puts forward a electronic fault diagnose method focusing on large-diameter astronomical telescope's armature winding, and ascertains if it is the resistance or inductance which is out of order. When it comes to armature winding's electronic fault, give the angular position a step signal, and compare the outputs of five models of normal, larger-resistance, smaller-resistance, larger-inductance and smaller-inductance, so we can position the fault. Firstly, we ascertain the transfer function of the angular position to the armature voltage, to analysis the output of armature voltage when the angular position's input is step signal. Secondly, ascertain the different armature currents' characteristics after armature voltage pass through different armature models. Finally, basing on the characteristics, we design two strategies of resistance and inductance separately. The author use MATLAB/Simulink function to model and emulate with the hardware parameters of the 2.5m-caliber telescope, which China and France developed cooperatively for Russia. Meanwhile, the author add a white noise disturbance to the armature voltage, the result shows its feasibility under a certain sized disturbance.

  7. Method and apparatus for monitoring armature position in direct-current solenoids

    Moyers, John C.; Haynes, Howard D.


    A method for determining the position of an armature of a dc-powered solenoid. Electrical circuitry is provided to introduce a small alternating current flow through the coil. As a result, the impedance and resistance of the solenoid coil can be measured to provide information indicative of the armature's position.

  8. A compact railgun accelerator for millimeter-sized dielectric solid armatures

    Zhukov, B. G.; Kurakin, R. O.; Sakharov, V. A.; Bobashev, S. V.; Ponyaev, S. A.; Reznikov, B. I.; Rozov, S. I.


    Millimeter-sized dielectric solid armatures have been accelerated in a compact railgun system. It is shown that application of an external pulsed magnetic field can solve the problem of catastrophic erosion of electrodes at the initial stage and accelerate small armatures up to a velocity of about 6 km/s.

  9. Method and apparatus for monitoring armature position in direct-current solenoids

    Moyers, John C. (Oak Ridge, TN); Haynes, Howard D. (Knoxville, TN)


    A method for determining the position of an armature of a dc-powered solenoid. Electrical circuitry is provided to introduce a small alternating current flow through the coil. As a result, the impedance and resistance of the solenoid coil can be measured to provide information indicative of the armature's position.


    Allison, Stephen W [ORNL; Cates, Michael R [ORNL; Goedeke, Shawn [ORNL; Crawford, M. T. [Institute for Advanced Technology, Austin, TX; Ferraro, S. B. [Institute for Advanced Technology, Austin, TX; Surls, D. [Institute for Advanced Technology, Austin, TX; Stewart, J. [Institute for Advanced Technology, Austin, TX


    The purpose of the present effort was to demonstrate 'on the fly' temperature measurement of railgun armatures on a bench top railgun. The effort builds on the previous test that utilized a portable unit with armature speeds ranging from 50 to 90 m/s. The tests described here involved higher speeds, ranging from 300 to 500 m/s. The method to accomplish the measurement involves pulsed laser illumination of a phosphor-coated armature. The duration of the ensuing fluorescence indicates temperature. The measured temperatures, obtained both inside the muzzle and outside in free flight, ranged between 80 to 110 C. The required pulsed fluorescence was made possible by successfully sensing the position of the armature while traveling within the laser illumination and fluorescence sensing fields-of-view. A high-speed camera also captured images of the moving armatures after exiting the railgun. These images sometimes included the fluorescing region of the phosphor coating.

  11. The lethal effects of the cibarial and pharyngeal armatures of mosquitoes on microfilariae.

    McGreevy, P B; Bryan, J H; Oothuman, P; Kolstrup, N


    Microfilariae of Wuchereria bancrofti and Brugia pahangi were killed by the chewing action of the cibarial and pharyngeal armatures and other papillae and spines in the fore-gut of mosquitoes. The proportion of ingested microfilariae that were killed was largely dependent on the presence and shape of the cibarial armature. Anopheles farauti No. 1 and Anopheles gambiae species A and B have well developed cibarial armatures and killed 36 to 96% of the ingested microfilariae. Culex pipiens fatigans has a poorly developed cibarial armature and killed only 6% of the microfilariae. Aedes aegypti and Aedes togoi lack cibarial armatures but have the remaining fore-gut structures. They killed only 2 to 22% of the microfilariae. The significance of these observations in relation to the control of filariasis with diethylcarbamazine is discussed.

  12. Comparative morphology of the pyloric armature of adult mosquitoes (Diptera: Culicidae).

    Tuten, H C; Bridges, W C; Adler, P H


    The structure of the pyloric armature, hypothesized to aid in blood-meal digestion or parasite resistance, was compared quantitatively among the following 8 species in 5 genera of adult mosquitoes from the southeastern United States: Aedes albopictus, Aedes japonicus, Aedes triseriatus, Anopheles punctipennis, Culex pipiens s.l., Culex restuans, Orthopodomyia signifera, and Toxorhynchites rutilus. Females differed significantly among species in the structure of spines composing the armature, with Aedes spp. forming one general group, Culex spp. another, and An. punctipennis and Or. signifera a third. Relationships of species based on structural characters of the armature were consistent with recent culicid phylogenies. Although pyloric armature has been noted in mosquitoes and other insects, this is the first quantitative investigation of the mosquito pyloric armature.

  13. Three-dimensional investigation of velocity skin effect in U-shaped solid armature

    Xin Li; Chunsheng Weng


    A three-dimensional transient computational model is applied to investigate the velocity skin effect (VSE) in a U-shaped solid arma-ture.With this model,current and heat transport in the armature can be evaluated accurately.The results show a local concentration of current and joule heating at the interface,and significant damage occurs at the edges of the armature.It is also observed that there is significant enhanced heating at sharp corners because of the armature geometry.The three-dimensional model can efficiently capture the salient features of the physical phenomena at the rail-armature interface,and contribute to the development of the armature design.

  14. 关于直流电动机的电枢绕组及电枢电路(二)电枢主电路%About the Armature Winding and Armature Circuit of DC Motor (Ⅱ)Armature Main Circuit

    王宗培; 陈敏祥


    电动机的电枢主电路包括:电枢绕组电路和电源二部分,属运动控制类的各种交流电动机,具有多相交流电枢绕组电路和逆变器供电的电源.与传统直流电动机原理一样的New DCM,具有直流的电枢绕组电路,通过电子换向器与直流电源相连.逆变器和电子换向器都是功率开关管的桥式电路,硬件电路上不易区分,容易混淆.本文用实例说明电子换向器不是逆变器,换向器构筑直流电枢绕组电路的独特功能,使得它与交流电枢绕组电路完全不同,电枢绕组电感对电动机运行性能的影响也随之不同.%The motor armature main circuit including: the armature winding circuit and power supply, all kinds of motion-control AC motors have the multiphase ac armature winding circuit and inverter power supply. The New DCM , with same principles of the traditional DC machines, has the DC armature winding circuit connected to DC power through electronic commutator. Inverter and electronic commutator is not easy to distinguish from hardware circuit structure, easy to confuse. This paper demonstrates the electronic commutator not inverter, the unique functions of the electronic commutator is to make the armature winding circuit as DC circuit, therefore , the armature winding circuits between New DCM and AC motor are completely different, the influences of the armature winding inductance to motor performance are different , too.

  15. Numerical simulation of flow through orifice meters

    Barry, J. J.; Sheikholeslami, M. Z.; Patel, B. R.


    The FLUENT and FLUENT/BFC computer programs have been used to numerically model turbulent flow through orifice meters. These simulations were based on solution of the Navier-Stokes equations incorporating a k-epsilon turbulence model. For ideal installations, trends in the discharge coefficient with Reynolds number, beta ratio, and surface roughness have been reproduced, and the value of the discharge coefficient has been computed to within 2 percent. Nonideal installations have also been simulated, including the effects of expanders, reducers, valves, and bends. Detailed modeling of flow through a bend has yielded results in good agreement with experimental data. The trend in discharge coefficient shifts for orifice meters downstream of bends has been predicted reasonably well.

  16. Orifice plate cavitation mechanism and its influencing factors

    Wan-zheng AI


    Full Text Available The orifice plate energy dissipater is an economic and highly efficient dissipater. However, there is a risk of cavitaion around the orifice plate flow. In order to provide references for engineering practice, we examined the cavitation mechanism around the orifice plate and its influencing factors by utilizing mathematical analysis methods to analyze the flow conditions around the orifice plate in view of gas bubble dynamics. Through the research presented in this paper, the following can be observed: The critical radius and the critical pressure of the gas nucleus in orifice plate flow increase with its initial state parameter ; the development speed of bubbles stabilizes at a certain value after experiencing a peak value and a small valley value; and the orifice plate cavitation is closely related to the distribution of the gas nucleus in flow. For computing the orifice plate cavitation number, we ought to take into account the effects of pressure fluctuation. The development time of the gas nucleus from the initial radius to the critical radius is about 10-7-10-5 s; therefore, the gas nucleus has sufficient time to develop into bubbles in the negative half-cycle of flow fluctuation. The orifice critical cavitation number is closely related to the orifice plate size, and especially closely related with the ratio of the orifice plate radius to the tunnel radius. The approximate formula for the critical cavitation number of the square orifice plate that only considers the main influencing factor was obtained by model experiments.

  17. Ablation and geometry change study of solid armature in a railgun

    Zhang Ya-Dong; Ruan Jiang-Jun; Hu Yuan-Chao; Gong Ruo-Han; Wen Wu


    Armature plays an important role in the electromagnetic launch process.Due to the skin effect,the current density distribution is neither uniform on the rail,nor on the armature.High current density centralization in one part could lead to a partial high temperature and make the armature material melt down and be ablated,especially at low velocity.In this paper we try to change the geometry of a Cshaped armature to improve the current density distribution and reduce the ablation.Four variants of C-shaped armatures are designed to study the specific features,including a conventional C-shaped armature (CCA),a rounded leading edge C-shaped armature (LCA),a rounded trailing edge C-shaped armature (TCA),and a rounded incorporate edge C-shaped armature (ICA).A novel low-speed experiment is constructed and tested.The armatures are ablated and recovered to compare the improved effects.Then finite element simulations according to the experimental results are performed to further analyze the experimental results.It is proved that the current density and hence the temperature distribution can be immensely improved by simply changing the armature geometry.LCA and ICA show that the erosion is more uniform on the contact surface due to the rounded leading edge.The curved trailing edge could improve the uniformity of the current on the interface.ICA which combines the effects of LCA and TCA is the best option in the four armatures.How much the leading edge and the trailing edge should be curved involves the geometry of CCA and the posture of the interface on the rail.A saddle shape is a good option to improve the current density and temperature distribution in the throat.Erosion mechanism is analyzed finally.The experiments and simulations support the erosion and transition mechanism.A detailed description of the experiments and simulations is also presented in this paper.

  18. Drikkevands optagelse af cadmium og bly fra armaturer

    Nielsen, K.

    Notatet omfatter rapporter fra to forsøgsrækker vedr. brugsvands optagelse af bly og cadmium. Den første omhandler brugsvandsarmaturers afgivelse af bly og cadmium til syntetisk brugsvand med en sammensætning svarende til en sur, blød vandtype. Forsøgene omfatter 10 armaturer og armaturdele....... Resultatet af forsøgene var, at et af armaturerne gav vandet et cadmiumindhold, der var væsentlig over den af WHO fastsatte grænse, mens 3 af armaturerne gav blyindhold, der var noget over denne grænse. Den anden rapport behandler afgivelse af cadmium og bly fra forskellige overflader til 3 forskellige...... at eksponere nogle armaturdele, som i Norge i praksis har vist at afgive meget store mængder bly og cadmium....

  19. Natural orifice transluminal endoscopy surgery: A review

    Jo(a)o Moreira-Pinto; Estev(a)o Lima; Jorge Correia-Pinto; Carla Rolanda


    Minimally invasive surgery started spreading worldwide in 1987, when the first laparoscopic cholecystectomy was performed. Meanwhile, improvement of endoscopic equipment and instruments allowed gastroenterologists to attempt more aggressive endoluminal interventions, even beyond the wall barrier. The first transgastric peritoneoscopy, in 2004, brought to light the concept of natural orifice transluminal endoscopic surgery (NOTES). The idea of incisionless surgery is attractive and has become a new goal for both surgeons and other people interested in this field of investigation. The authors present a review of all developments concerning NOTES, including animal studies and human experience.

  20. Differentiation of females in Sergentomyia sensu stricto (Diptera: Psychodidae) using scanning electron microscopy of pharyngeal armatures.

    Benabdennbi, I; Bombard, S; Braverman, Y; Pesson, B


    Scanning electron microscopy of external ornamentation and internal armature of the pharynx was used to identify females of Sergentomyia sensu stricto. Five species from the eastern Mediterranean basin were compared; S. minuta clearly was separated from species of the fallax-group. Within the fallax-group, S. fallax was distinguished readily by its heart-shaped pharynx and the difference in armature between the dorsal and lateral plates.

  1. Solid-to-hybrid transitioning armature railgun with non-conforming-to-prejudice bore profile

    Solberg, Jerome Michael


    An improved railgun, railgun barrel, railgun projectile, and railgun system for accelerating a solid-to-hybrid transitioning armature projectile using a barrel having a bore that does not conform to a cross-sectional profile of the projectile, to contact and guide the projectile only by the rails in a low pressure bore volume so as to minimize damage, failure, and/or underperformance caused by plasma armatures, insulator ablation, and/or restrikes.

  2. Design Considerations and Experimental Verification of a Rail Brake Armature Based on Linear Induction Motor Technology

    Sakamoto, Yasuaki; Kashiwagi, Takayuki; Hasegawa, Hitoshi; Sasakawa, Takashi; Fujii, Nobuo

    This paper describes the design considerations and experimental verification of an LIM rail brake armature. In order to generate power and maximize the braking force density despite the limited area between the armature and the rail and the limited space available for installation, we studied a design method that is suitable for designing an LIM rail brake armature; we considered adoption of a ring winding structure. To examine the validity of the proposed design method, we developed a prototype ring winding armature for the rail brakes and examined its electromagnetic characteristics in a dynamic test system with roller rigs. By repeating various tests, we confirmed that unnecessary magnetic field components, which were expected to be present under high speed running condition or when a ring winding armature was used, were not present. Further, the necessary magnetic field component and braking force attained the desired values. These studies have helped us to develop a basic design method that is suitable for designing the LIM rail brake armatures.

  3. Magnetic Actuation Connector Between Extension Shaft and Armature for Bottom Mounted Control Rod Drive Mechanism

    Huh, Hyung; Cho, Yeong Garp; Kim, Jong In [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)


    The electromagnet and armature inside the guide tube interact and produce magnetism, thus making the armature, connecting extension shaft and control rod move up and down to control the power of reactor. During the overhaul, the control absorber rod (CAR), extension shaft, and armature of BMCRDM are lifted together for closing a seal valve. But total length of CAR assembly is so long that it cannot be lifted due to exposure above the water level of pool which is strictly controlled. In addition to this, it is difficult to calibrate a position indicator and lifting force of electromagnet without armature assembly as a seal valve is closed. For this reason, it is necessary to install a disconnecting system between armature and extension shaft. Therefore, KAERI has developed magnetic actuation connector using plunger between armature and extension shaft for the bottom mounted control rod drive mechanism in research reactor. The results of a FEM and the experiments in this work lead to the following conclusions: The FEM result for the design of the magnetic actuation connector is compared with the measured lifting force of prototype production. As a result, it is shown that the lifting force of the prototype connector has a good agreement with the result of the FEM. A newly developed technique of prototype magnetic actuation connector which is designed by FEM analysis result is proposed.

  4. Gaseous Nitrogen Orifice Mass Flow Calculator

    Ritrivi, Charles


    The Gaseous Nitrogen (GN2) Orifice Mass Flow Calculator was used to determine Space Shuttle Orbiter Water Spray Boiler (WSB) GN2 high-pressure tank source depletion rates for various leak scenarios, and the ability of the GN2 consumables to support cooling of Auxiliary Power Unit (APU) lubrication during entry. The data was used to support flight rationale concerning loss of an orbiter APU/hydraulic system and mission work-arounds. The GN2 mass flow-rate calculator standardizes a method for rapid assessment of GN2 mass flow through various orifice sizes for various discharge coefficients, delta pressures, and temperatures. The calculator utilizes a 0.9-lb (0.4 kg) GN2 source regulated to 40 psia (.276 kPa). These parameters correspond to the Space Shuttle WSB GN2 Source and Water Tank Bellows, but can be changed in the spreadsheet to accommodate any system parameters. The calculator can be used to analyze a leak source, leak rate, gas consumables depletion time, and puncture diameter that simulates the measured GN2 system pressure drop.

  5. Orifice plate cavitation mechanism and its influencing factors

    Wan-zheng AI; Tian-ming DING


    The orifice plate energy dissipater is an economic and highly efficient dissipater.However,there is a risk of cavitaion around the orifice plate flow.In order to provide references for engineering practice,we examined the cavitation mechanism around the orifice plate and its influencing factors by utilizing mathematical analysis methods to analyze the flow conditions around the orifice plate in view of gas bubble dynamics.Through the research presented in this paper,the following can be observed:The critical radius and the critical pressure of the gas nucleus in orifice plate flow increase with its initial state parameter τ0;the development speed of bubbles stabilizes at a certain value after experiencing a peak value and a small valley value;and the orifice plate cavitation is closely related to the distribution of the gas nucleus in flow.For computing the orifice plate cavitation number,we ought to take into account the effects of pressure fluctuation.The development time of the gas nucleus from the initial radius to the critical radius is about10-7-10-5 s;therefore,the gas nucleus has sufficient time to develop into bubbles in the negative half-cycle of flow fluctuation.The orifice critical cavitation number is closely related to the orifice plate size,and especially closely related with the ratio of the orifice plate radius to the tunnel radius.The approximate formula for the critical cavitation number of the square orifice plate that only considers the main influencing factor was obtained by model experiments.

  6. Hybrid transvaginal natural orifice transluminal endoscopic surgery-kolecystektomi

    Boesen, Line; Meisner, Søren; Vilmann, Peter


    Natural orifice transluminal endoscopic surgery (NOTES) is a minimally invasive surgical technique where access to the abdominal cavity is achieved through one of the natural orifices of the body. Based on experience from gynaecology, transvaginal access has been the easiest NOTES technique...

  7. [Natural orifice transluminal endoscopic surgery: current situation].

    Delgado, Salvadora; Ibarzábal, Ainitze; Fernández-Esparrach, Glòria


    Natural orifice transluminal endoscopic surgery (NOTES) is the paradigm of the evolution of minimally invasive surgery. The laparoscopic has introduced new ideas in general surgery, one of them being that modern surgery is the work of multidisciplinary teams. A clear example of this is provided by NOTES. The aim of this type of surgery is to perform conventional laparoscopic procedures without incision, using flexible endoscopic technology usually employed in the diagnosis and treatment of intraluminal lesions and reaching the inside of the abdominal cavity through natural orifices (mouth, anus, vagina and even urethra). This type of access opens a highly interesting field for certain types of patients, such as those with high surgical risk, the morbidly obese, and those with multiple prior abdominal interventions or surgical wound infections. Animal models have shown that a wide variety of interventions (cholecystectomy, appendicectomy, splenectomy, hysterectomy, tubal ligations, gastroenteroanastomosis, peritoneoscopy, liver biopsy and herniorrhaphy, among others) can be performed. However, before use in humans, this new technique must be shown to be safe and to provide real advantages for patients. To do this, a series of issues, including safe methods for closure of the gastric incision and the avoidance of infections, among others, must be solved. Another critical element for the development of this new type of surgery is the creation of appropriate instrumentation, requiring input not only from medical professionals but also from engineers and industry. The present article describes the major advances made in NOTES since this technique was first described and analyzes the risks and potential benefits associated with this novel procedure.

  8. Minimum wall pressure coefficient of orifice plate energy dissipater

    Wan-zheng Ai; Jia-hong Wang


    Orifice plate energy dissipaters have been successfully used in large-scale hydropower projects due to their simple structure, convenient construction procedure, and high energy dissipation ratio. The minimum wall pressure coefficient of an orifice plate can indirectly reflect its cavitation characteristics:the lower the minimum wall pressure coefficient is, the better the ability of the orifice plate to resist cavitation damage is. Thus, it is important to study the minimum wall pressure coefficient of the orifice plate. In this study, this coefficient and related parameters, such as the contraction ratio, defined as the ratio of the orifice plate diameter to the flood-discharging tunnel diameter;the relative thickness, defined as the ratio of the orifice plate thickness to the tunnel diameter;and the Reynolds number of the flow through the orifice plate, were theoretically analyzed, and their relationships were obtained through physical model experiments. It can be concluded that the minimum wall pressure coefficient is mainly dominated by the contraction ratio and relative thickness. The lower the contraction ratio and relative thickness are, the larger the minimum wall pressure coefficient is. The effects of the Reynolds number on the minimum wall pressure coefficient can be neglected when it is larger than 105. An empirical expression was presented to calculate the minimum wall pressure coefficient in this study.

  9. Minimum wall pressure coefficient of orifice plate energy dissipater

    Wan-zheng AI


    Full Text Available Orifice plate energy dissipaters have been successfully used in large-scale hydropower projects due to their simple structure, convenient construction procedure, and high energy dissipation ratio. The minimum wall pressure coefficient of an orifice plate can indirectly reflect its cavitation characteristics: the lower the minimum wall pressure coefficient is, the better the ability of the orifice plate to resist cavitation damage is. Thus, it is important to study the minimum wall pressure coefficient of the orifice plate. In this study, this coefficient and related parameters, such as the contraction ratio, defined as the ratio of the orifice plate diameter to the flood-discharging tunnel diameter; the relative thickness, defined as the ratio of the orifice plate thickness to the tunnel diameter; and the Reynolds number of the flow through the orifice plate, were theoretically analyzed, and their relationships were obtained through physical model experiments. It can be concluded that the minimum wall pressure coefficient is mainly dominated by the contraction ratio and relative thickness. The lower the contraction ratio and relative thickness are, the larger the minimum wall pressure coefficient is. The effects of the Reynolds number on the minimum wall pressure coefficient can be neglected when it is larger than 105. An empirical expression was presented to calculate the minimum wall pressure coefficient in this study.

  10. Derivation of armature displacement and movement disturbances from current and voltage measurements on solenoid operated valves

    Louati, Iskander Alexandre [AREVA NP GmbH (Germany). Service Sector Germany


    As part of the electric drive mechanisms of the safety system in nuclear power plants safety related solenoid operated valves (SOVs) are subject to design control, commissioning tests and periodical in-service inspections. AREVA has developed and qualified many methods and tools that have been embedded into as software tools called DAM for diagnosis and evaluation of the valve performance according to the KTA requirements. In the special case of COVs tracing the electric measurements with ADAM helps to detect anomalies at the SOVs and esp. those related to disturbances of the armature moved. The disturbances to be tested are divided into electrical and mechanical disturbances: voltage insufficiency, switch chattering; degradation of spring load, friction collaterally to armature displacement, partial or total obstruction of the armature.

  11. Ultimate kinematic characteristics of rail electromagnetic launchers with metal armatures in an external magnetic field

    Stankevich, S. V.; Shvetsov, G. A.


    This paper presents the results of numerical simulation of the Joule heating of the armature and rails in rail launchers of metal bodies with one or two augmenting rails generating an external magnetic field. The ultimate projectile velocity is calculated under the assumption that the Joule heating of the armature and rails during acceleration does not exceed the melting temperature of the materials of which they are made. It is shown that, with an appropriate choice of the position of the coils generating the augmenting magnetic field with respect to the launcher channel and the current magnitude in them, the heat load on the rails and armature in electromagnetic launchers of solids can be substantially reduced and the ultimate kinematic characteristics of these launchers in crisis-free regimes can be considerably increased.

  12. Magnetic Flux Compression Using Detonation Plasma Armatures and Superconductor Stators: Integrated Propulsion and Power Applications

    Litchford, Ron; Robertson, Tony; Hawk, Clark; Turner, Matt; Koelfgen, Syri


    This presentation discusses the use of magnetic flux compression for space flight applications as a propulsion and other power applications. The qualities of this technology that make it suitable for spaceflight propulsion and power, are that it has high power density, it can give multimegawatt energy bursts, and terawatt power bursts, it can produce the pulse power for low impedance dense plasma devices (e.g., pulse fusion drivers), and it can produce direct thrust. The issues of a metal vs plasma armature are discussed, and the requirements for high energy output, and fast pulse rise time requires a high speed armature. The plasma armature enables repetitive firing capabilities. The issues concerning the high temperature superconductor stator are also discussed. The concept of the radial mode pulse power generator is described. The proposed research strategy combines the use of computational modeling (i.e., magnetohydrodynamic computations, and finite element modeling) and laboratory experiments to create a demonstration device.

  13. Composite solid armature consolidation by pulse power processing - A novel homopolar generator application in EML technology

    Persad, C.; Peterson, D. R.; Zowarka, R. C.


    Graded electrical resistance and assured sliding contact are among the desirable characteristics for the solid armatures used in railguns attainable through the use of composite materials. Metal-metal, metal-ceramic, and metal-polymer composites are generic types of potential solid armature materials. The authors describe the production of these composites by a novel experimental approach that uses a homopolar generator in a pulse-powered materials consolidation system. The processing of Copper-tungsten and aluminum-alumina composites is used to demonstrate versatility of the homopolar generator as a materials processing tool. Powder metallurgy and laminate bonding approaches have been utilized. Composite solid armature materials have been consolidated with subsecond high-temperature exposure. Densification in the solid state proceeds by a warm/hot forging mechanism, and fully dense composites are obtained by a combined application of pressure and a controlled energy input.

  14. Impact of the sleeve thickness on the armature eccentricity in a solenoid valve

    Goraj Robert


    Full Text Available Most studies on solenoid valves (SVs assumed that the armature is concentrically positioned in the sleeve. Under this assumption the transversal component of the magnetic force is equal zero. The article presents an analytical calculation model for the estimation of the armature eccentricity. Using this model the eccentricity was calculated as a function of the sleeve thickness and the hydraulic clearance between the armature and the sleeve. After finding the eccentricity also the permeance of the radial air gap was calculated. This permeance has a direct influence on the drop of the magnetomotive force in the magnetic circuit and finally influences also the axial component of the magnetic force. In the article a calculation of both transversal and axial components of the magnetic force was carried out and presented in the appendix to the article.

  15. Design and evaluation of carbon fibre-reinforced launch packages with segmented, copper and molybdenum fibre armatures

    Koops, M.; Huijser, T.; Karthaus, W.


    Fibre armatures have been studied both dynamically and statically to gain insight in their electrothermal and mechanical behaviour. In the first part of this paper, the results of launch experiments with single and multi-segment copper and molybdenum fibre armatures integrated in carbon-fibre reinfo

  16. Transition Armature Study. Progress report No. 4, February 1--March 31, 1992

    Hawke, R.S.


    This forth report covers the period February 1 to March 31, 1992. During this period we: (1) performed numerical simulations of plasma brush formation and evolution with a 1D MHD code, (2) commenced testing hybrid armature brushes with a test fixture for studying hybrid armature brush behavior, (3) acquired 7m of the LTS railgun containment structure for a 3 year loan, (4) began evaluation of 3D Electro-Magnetic codes and their suitability to be interfaced to existing 3D stress/strain and thermal codes and (5) conducted a program review at LLNL.

  17. Identification of Culex (Melanoconion) species of the United States using female cibarial armature (Diptera: Culicidae).

    Williams, Martin R; Savage, Harry M


    Species within the subgenus Culex (Melanoconion) Theobald are the primary enzootic vectors of viruses in the Venezuelan equine encephalitis complex including Everglades virus, and probable enzootic vectors of eastern equine encephalitis and West Nile viruses. Adult females of this subgenus are often difficult or impossible to identify to species based on external morphological characters. The use of female cibarial armature allows for the identification of field-collected adult female specimens of Culex (Melanoconion). The cibarial armatures are described and illustrated for all species from the United States and a key to species using this character is presented.

  18. Armature reaction effects on a high temperature superconducting field winding of an synchronous machine: experimental results

    Mijatovic, Nenad; Jensen, Bogi Bech


    This paper presents experimental results from the Superwind laboratory setup. Particular focus in the paper has been placed on describing and quantifying the influence of armature reaction on performance of the HTS filed winding. Presented experimental results have confirmed the HTS field winding...... sensitivity to both armature reaction intensity and angular position with respect to the HTS coils. Furthermore, the characterization of the HTS field winding has been correlated to the electromagnetic torque of the machine where the maximal Ic reduction of 21% has been observed for the maximum torque....

  19. Armature reaction effects on a high temperature superconducting field winding of an synchronous machine: experimental results

    Mijatovic, Nenad; Jensen, Bogi Bech


    This paper presents experimental results from the Superwind laboratory setup. Particular focus in the paper has been placed on describing and quantifying the influence of armature reaction on performance of the HTS filed winding. Presented experimental results have confirmed the HTS field winding sensitivity to both armature reaction intensity and angular position with respect to the HTS coils. Furthermore, the characterization of the HTS field winding has been correlated to the electromagnetic torque of the machine where the maximal Ic reduction of 21% has been observed for the maximum torque.

  20. Investigation of the residue in an electric rail gun employing a plasma armature

    Bauer, D. P.; Barber, J. P.


    The performance of dc electric rail guns using plasma-armature-accelerated projectiles was studied. It was found that the initial rail launcher acceleration profile was consistent with the simulation, but that after the projectile had traveled approximately 25 to 30 cm along the gun, a considerable portion of the current in the projectile armature commutated into a secondary current path. Also noted were the lower than expected muzzle velocities. It was proposed that the secondary current path was a relatively high conductivity layer of residue on the launcher bore.



    In the process of the emergence gate shutting of one orifice tunnel, a big noise and great vibration may be observed in the mid gate chamber. In order to guarantee the working safety of orifice tunnels, an experimental investiga-tion is carried out in Sichuan University. In the investigation,the fluctuation pressure along the tunnel and the wind velocity in the entry of emergency gate are measured. In the mean time, the fluid state in orifice tunnel is carefully observed and analyzed. The reasons of the noise and vibration in the mid gate chamber are found out and some countermeasures are presented in this paper. The conclusions are useful to the ori-fice tunnels with high water head and huge discharge.

  2. Fabrication of small-orifice fuel injectors for diesel engines.

    Woodford, J. B.; Fenske, G. R.


    Diesel fuel injector nozzles with spray hole diameters of 50-75 {micro}m have been fabricated via electroless nickel plating of conventionally made nozzles. Thick layers of nickel are deposited onto the orifice interior surfaces, reducing the diameter from {approx}200 {micro}m to the target diameter. The nickel plate is hard, smooth, and adherent, and covers the orifice interior surfaces uniformly.

  3. The internal structure and dynamics of the railgun plasma armature between infinitely wide ablating rails

    Frese, M. H.

    Conventional guns cannot achieve projectile velocities much greater than the sound speed in burned chemical propellants. Plasma armature railguns should not be subject to the same type of velocity limit. However, experiments indicate that there may be some other mechanism which can limit the velocity. A theory that accurately predicts the observed velocity limit could provide the insight necessary to raise or even lift that limit. As yet, there is no theoretical explanation drawn from physical first principles which predicts a limit to the achievable velocity. This report describes the first phase of an effort to use two-dimensional dynamic magnetohydrodynamic (MHD) simulation of the plasma motion in the bore to produce such an explanation. In this phase, MACH2, an Air Force two-dimensional MHD code has been quickly adapted to this problem. The principal goal of this effort was to demonstrate the feasibility and desirability of using MACH2 for railgun armature simulation. However, the simulations of plasma armatures described here are the most sophisticated models of the railgun arc presently available; they show the armature as a dynamic and developing plasma in a way never before seen. The goal could not have been more clearly achieved.

  4. Orifice plate for controlling solids flow, methods of use thereof and articles comprising the same

    Jukkola, Glen D.; Teigen, Bard C.


    Disclosed herein is an orifice plate comprising one or more plates having orifices disposed therein; the orifices being operative to permit the flow of solids from a moving bed heat exchanger to a solids flow control system; where the orifice plate is downstream of a tube bundle of the moving bed heat exchanger and upstream of the solids flow control system and wherein the orifice plate is operative to evenly distribute the flow of solids in the solids flow control system.

  5. Effects of Armature Winding Segmentation with Multiple Converters on the Short Circuit Torque of 10-MW Superconducting Wind Turbine Generators

    Liu, Dong; Polinder, Henk; Abrahamsen, Asger Bech;


    Superconducting synchronous generators (SCSGs) are drawing more attention in large direct-drive wind turbine applications. Despite low weight and compactness, the short circuit torque of an SCSG may be too high for wind turbine constructions due to a large magnetic air gap of an SCSG. This paper...... aims at assessing the effects of armature winding segmentation on reducing the short circuit torque of 10-MW SCSGs. A concept of armature winding segmentation with multiple power electronic converters is presented. Four SCSG designs using different topologies are examined. Results show that armature...

  6. Meibomian orifices and Marx's line. Studied by triple vital staining.

    Norn, M


    The ciliary margins of the lower lids have been vital stained by the lipid-specific Sudan III powder, fluorescein 0.1% and the bottom of the lacrimal river (Marx's line) by lissamine green 1% in 100 cases. The Meibomian orifices are situated in a straight row just in front of the Marx's line in the lipid phase. With increasing age (greater than 50 years) the orifices are more often displaced and also discharge their lipid in the depth of the aqueous phase. The number averaged 21.5 in the lipid phase and 1.7 in the aqueous phase. Active orifices staining with lipid were found in 45% of all orifices in normals, independent of age, and were increased in conjunctivitis in the lipid phase. Lissamine green-stained orifices were independent of age, phase and diagnosis. The anterior edge of Marx's line may run an irregular course in elderly normals (greater than 50 years), significantly more often in conjunctivitis and blepharitis.

  7. A pulse-tube refrigerator using variable-resistance orifice

    Huang, B. J.; Sun, B. W.


    In the present study, we propose a new design of orifice pulse-tube refrigerator (VROPT) using a variable-resistance valve to replace the conventional orifice. The variable-resistance orifice (VRO) is basically a high-speed solenoidal valve similar to the fuel jet device widely used in automobile engines. By changing the frequency and periods of ON and OFF of the valve through an electronic device, we can change the flow resistance of the VRO. This thus provides a possibility for an OPT to be controlled on-line during operation. From the results obtained in the present study, we have shown that VROPT is able to achieve on-line control by regulating the duty cycle d or frequency fv of the VRO. We also show that VROPT will not loss its thermal performance as compared to conventional OPT.

  8. Primary gastric teratoma on the cardiac orifice in an adult

    Liu Liu; Wen Zhuang; Zhong Chen; Yong Zhou; Xiao-Ran Huang


    Gastric teratoma (GT) is a seldom seen congenital abnormality. GT always occurs in children. The greater curvature and posterior wall of the stomach are the most common sites involving GT. We diagnosed a case of GT located on the inferior wall of the cardiac orifice in a 20-year-old man. To the best of our knowledge, this is the first case of GT located on the wall of the cardiac orifice in an adult in the English literature. We report this unusual case as an addition to this rare disease usually found in children. Computed tomography combined with endoscopic ultrasonography can be selected to diagnose GT.

  9. Qualification and inspection of armatures in the component test facility KOPRA; Armaturenqualifikationen und -inspektionen in der Komponentenpruefanlage KOPRA

    Herr, Wolfgang; Schoepf, Moritz; Stecher, Willi; Wallaschek, Sebastian [AREVA NP GmbH, Erlangen (Germany). Komponentenqualifikation Erlangen


    The KOPRA test facility is an authorized testing rig for reactor component qualification and inspection. Due to the combination of two pressurizers the testing of any armature in closed or open circuit is possible. The authors describe in detail the qualification of controllable splash valves for German PWR plants, functionality tests of gate valves for the NPP Olkiluoto 3. The testing facility is performing inspection, qualification and diagnosis tasks of safety relevant armatures in the frame of periodic safety analyses.

  10. Spectroscopic measurements of railgun plasma armatures in an augmented railgun using a permanent magnet

    Katsuki, S.; Sueda, T.; Koga, Y.; Akiyama, H. [Kumamoto Univ. (Japan). Dept. of Electrical Engineering and Computer Science; Sato, K.N. [National Inst. for Fusion Science, Nagoya (Japan)


    Small bore railguns have been developed to demonstrate the acceleration of frozen hydrogen pellets which are used to refuel magnetically confined fusion reactors. Here, measurements of electron density using Stark broadening of the H{sub a} line are performed to investigate the behavior of plasma armatures in railguns with and without an augmenting magnetic field. A permanent magnet with a magnetic flux density of 1.25 T was used to augment the magnetic field of one railgun. Driving currents of 20 and 25 kA are supplied to the railguns with and without the augmenting magnetic field, respectively, in order to maintain the same peak Lorentz force on the projectile. Also a gradual temporal increase in electron density and length of the plasma armature is observed in the augmented railgun.

  11. 2-D viscous magnetohydrodynamics simulation of plasma armatures with the CE/SE method

    LI Xin; WENG ChunSheng


    A possible two-dimensional viscous magnetohydrodynamics (MHD) model is applied to investigating the plasma armature in a railgun. The space-time conservation element and solution element (CE/SE) method for solving the coupled Navier-Stokes equations and Maxwell equations was devised. The dis-tributions of physical parameters of the plasma may thus be evaluated. The results show that extremely high pressure can always be observed ahead of the projectile, and the Lorentz force is the main pro-puIsion. The distribution of temperature is in a good agreement with the results predicted by the law of radiation at the boundaries. Due to convection, the circulation patterns of velocity are evident in both the cases considering inviscid and viscous effect. Furthermore, the velocity and acceleration oscillate over time until a new steady state is achieved. This model efficiently captures the salient features of the physical phenomena, and contributes to further studies of MHD problems in plasma armature.

  12. Inventaire préliminaire des armatures du Néolithique gersois.

    Jean-Pierre Cantet


    Full Text Available La présente contribution a pour but de recenser les armatures   attribuables au Néolithique ou au Chalcolithique du département du Gers, afin d'offrir un premier corpus de ce type d'artefacts pour les régions d'entre Pyrénées et Garonne où les diverses phases culturelles du Néolithique restent encore mal caractérisées.

  13. Vehicle test report: South Coast Technology electric Volkswagen Rabbit with developmental low-power armature chopper

    Marte, J. E.; Bryant, J. A.; Livingston, R.


    Dynamometer performance of a South Coast Technology electric conversion of a Volkswagen (VW) Rabbit designated SCT-8 was tested. The SCT-8 vehicle was fitted with a transistorized chopper in the motor armature circuit to supplement the standard motor speed control via field weakening. The armature chopper allowed speed control below the motor base speed. This low speed control was intended to reduce energy loss at idle during stop-and-go traffic; to eliminate the need for using the clutch below base motor speed; and to improve the drivability. Test results indicate an improvement of about 3.5% in battery energy economy for the SAE J227a-D driving cycle and 6% for the C-cycle with only a minor reduction in acceleration performance. A further reduction of about 6% would be possible if provision were made for shutting down field power during the idle phases of the driving cycles. Drivability of the vehicle equipped with the armature chopper was significantly improved compared with the standard SCT Electric Rabbit.

  14. The armature in the genital atrium as a new taxonomic character distinguishing females of Phlebotomus papatasi and P. duboscqi (Diptera: Psychodidae).

    Pesson, B; Madulo-Leblond, G; Killick-Kendrick, M; Tang, Y; Killick-Kendrick, R


    Descriptions are given of armatures in the genital atria of females of the two morphologically similar sandfly species, Phlebotomus papatasi and P. duboscqi. The species are distinguishable by the size and shape of the armature, the grouping of the spines in the armature and the length and shape of the spines. These characters have been shown to separate females of other closely related species of phlebotomine sandflies.



    The cavitation of orifices is one of the main problems of the Xiaolangdi flood discharge tunnels. Along with the decompression experiment, the flow field was calculated in this paper by using an axis-symmetrical k-ε turbulence model. The calculated pressure distribution was compared with the measured data and in agreement with each other. The calculated results show that few of the cavitation bubbles generating at the orifice edge can reach the wall under the calculation condition, the force applied on the orifice surface and the flow pattern before the orifice may be improved obviously by adding the vortex elimination ring at the upper side of the orifice.

  16. The Effects of Fluid Viscosity on the Orifice Rotameter

    Jiang Wei


    Full Text Available Due to the viscous shear stress, there is an obvious error between the real flow rate and the rotameter indication for measuring viscous fluid medium. At 50 cSt the maximum error of DN40 orifice rotameter is up to 35 %. The fluid viscosity effects on the orifice rotameter are investigated using experimental and theoretical models. Wall jet and concentric annulus laminar theories were adapted to study the influence of viscosity. And a new formula is obtained for calculating the flow rate of viscous fluid. The experimental data were analyzed and compared with the calculated results. At high viscosity the maximum theoretical results error is 6.3 %, indicating that the proposed measurement model has very good applicability.

  17. Head loss coefficient through sharp-edged orifices

    Adam, Nicolas J.; De Cesare, Giovanni; Schleiss, Anton J.; Richard, Sylvain; Muench-Alligné, Cécile


    Nowadays, high-head power plants could increase their installed power capacity for many reasons, e.g. dam heightening, increase of their peak power capacity or refurbishment with new turbines. Frequently, due to several considerations, e.g. topographical or economical limitations, the existing surge tank cannot be extended to keep previous safety levels and efficiency. A valuable way to adapt these surge tanks is to place a throttle at their entrance like, for example, an orifice. The main effect of this adaptation is the introduction of head losses that reduce the extreme levels in the surge tank due to the mass oscillations resulting from a closure or opening of downstream discharge control. This research studies the influence of the edge angle of a ASME-standard orifice on the head losses. This angle introduces an asymmetrical behavior and influences head losses. Different angles are tested from 0° to the 67° (biggest angle possible for this configuration). The first step of this study is to determine experimentally the steady losses produced by orifice for several discharges. In the second step, a numerical model on ANSYS CFX is performed. Combining the two approaches, it is possible to understand and quantify the effect of the edge angle.

  18. Development of honeycomb type orifices for flow zoning in PFBR

    Pandey, G.K., E-mail:; Ramdasu, D.; Padmakumar, G.; Prakash, V.; Rajan, K.K.


    Highlights: • Cavitation free flow zoning devices are developed for reactor core in PFBR. • These devices are experimentally investigated for their hydraulic characteristics. • Pressure drop and cavitation are two main characteristics to be investigated. • Various configurations of devices utilized in different zones are discussed. • Loss coefficient for each configuration is compared and reported. -- Abstract: The prototype fast breeder reactor (PFBR) is in its advanced phase of construction at Kalpakkam, India. It is a sodium cooled, pool type reactor with two loop concept where each loop have one primary sodium pump (PSP), one secondary sodium pump (SSP) and two intermediate heat exchangers (IHX). PFBR core subassemblies (SA) are supported vertically inside the sleeves provided in the grid plate (GP). The GP acts as a coolant header through which flow is distributed among the SA to remove fission heat. Since the power profile of the reactor core is not uniform, it is necessary to distribute the coolant flow (called flow zoning) to each subassembly according to their power levels to get maximum mean outlet temperature of sodium at core outlet. To achieve this, PFBR core is divided into 15 zones such as fuel, blanket, reflector, storage, etc. according to their respective power levels. The flow zoning in the different SAs of the reactor core is achieved by installing permanent pressure dropping devices in the foot of the subassembly. Orifices having honey-comb type geometry were developed to meet the flow zoning requirements of fuel zone. These orifices being of very complex geometry requires precision methods of manufacturing to achieve the desired shape under specified tolerances. Investment casting method was optimized to manufacture this orifice plate successfully. Hydraulics of these orifices is important in achieving the required pressure drop without cavitation. The pressure drop across these orifice geometries depends mainly on geometrical

  19. Simulation and Test for the Thermal Behaviour of a Prototype Synchronous Generator with HTS Armature Windings

    Yu, X.-Y.; Qu, T.-M.; Song, P.; Li, L.-N.; Chen, D.-X.; Han, Z.

    A synchronous generator prototype with HTS armature windings and a permanent magnet rotor (HTS-PM) was developed. The temperature evolution during cooling and operation processes of the HTS coils was analyzed by finite element method (FEM). The simulated results coincided well with the temperature measurement data acquired by PT-100 sensors. Cooling time, terminal temperature, contact thermal conductivity, during cooling, as well as the proportion between real and calculated iron loss, contact thermal conductivity, at various rotating speeds during operation, were worked out using the FEM model.

  20. Impact Of The Pulse Width Modulation On The Temperature Distribution In The Armature Of A Solenoid Valve

    Goraj R.


    Full Text Available In order to estimate the inductive power set in the armature of the high-speed solenoid valve (HSV during the open loop control (OLC using pulse width modulation (PWM an analytical explicit formula has been derived. The simplifications taken both in the geometry and in the physical behavior of the HSV were described. The inductive power was calculated for different boundary conditions and shown as a function of the frequency of the coil current. The power set in the armature was used as an input to the thermal calculation. The thermal calculation had an objective to estimate the time dependent temperature distribution in the armature of the HSV. All the derivation steps were presented and the influence of different boundary conditions was shown and discussed. The increase of the temperature during the heating with inductive power has been evaluated both in the core and on the side surface of the HSV.

  1. Impact Of The Pulse Width Modulation On The Temperature Distribution In The Armature Of A Solenoid Valve

    Goraj, R.


    In order to estimate the inductive power set in the armature of the high-speed solenoid valve (HSV) during the open loop control (OLC) using pulse width modulation (PWM) an analytical explicit formula has been derived. The simplifications taken both in the geometry and in the physical behavior of the HSV were described. The inductive power was calculated for different boundary conditions and shown as a function of the frequency of the coil current. The power set in the armature was used as an input to the thermal calculation. The thermal calculation had an objective to estimate the time dependent temperature distribution in the armature of the HSV. All the derivation steps were presented and the influence of different boundary conditions was shown and discussed. The increase of the temperature during the heating with inductive power has been evaluated both in the core and on the side surface of the HSV.

  2. Phlebotomine sandflies of Kenya (Diptera: Psychodidae). IV. The armature in the genital atrium of female Larroussius as a means of identification.

    Killick-Kendrick, R; Tang, Y; Killick-Kendrick, M


    Descriptions are given of armatures in the genital atria of the six known Kenyan species of phlebotomine sandflies of the subgenus, Larroussius, namely Phlebotomus aculeatus, P. elgonensis, P. guggisbergi, P. longipes, P. orientalis and P. pedifer. Phlebotomus aculeatus, P. longipes and P. pedifer can be recognized by the shapes of their armatures. Differences in the length and arrangement of the spines in the armature of P. elgonensis and P. longipes are diagnostic features. The distinguishing feature of P. guggisbergi is a wide variation in spine thickness. The most notable feature of P. orientalis is the angle at which the spines lie. The appearance of the base of the spermathecal duct remains the method of choice for the identification of all six but, if this feature is not well displayed in dissected females, they can be distinguished by the armature. It is suggested that descriptions of new species should include an illustration of the armature in the genital atrium.

  3. Comparisons of nozzle orifice processing methods using synchrotron X-ray micro-tomography

    Zhi-jun WU; Zhi-long LI; Wei-di HUANG; Hui-feng GONG; Ya GAO; Jun DENG; Zong-jie HU


    Based on the high flux synchrotron X-ray of the Shanghai Synchrotron Radiation Facility (SSRF),high precision 3D digital models of diesel nozzle tips have been established by X-ray micro-tomography technology,which reveal the internal surfaces and structures of orifices.To analyze the machining precision and characteristics of orifice processing methods,an approach is presented based on the parameters of the internal structures of nozzle orifices,including the nozzle diameter,the orifice inner surface waviness,the eccentricity distance and the angle between orifices.Using this approach,two kinds of nozzle orifice processing methods,computerized numerical control drilling and electric discharge machining,have been studied and compared.The results show that this approach enables a simple,direct,and comprehensive contrastive analysis of nozzle orifice processing methods.When processing a single orifice,the electric discharge machining method has obvious advantages.However,when there are multiple orifices,the error levels of the two methods are similar in relation to the symmetry of distribution of the orifices.

  4. Kilowatt Isotope Power System: component test report for the ground demonstration system jet condenser orifice performance. 77-KIPS-103

    Brainard, E.L.


    The purpose of these tests was to determine which orifice elements achieved satisfactory hydraulic and thermal performance prior to their incorporation into the Jet Condenser Assembly. Requirements were as set forth within the Kilowatt Isotope Power System (KIPS) Component Test Procedure number 414 for the Jet Condenser Orifice Performance testing. The results of the performance testing conducted on the Jet Condenser Orifices are presented. Part Number 720841 Jet Condenser Orifice Nozzle successfully completed the orifice screening tests.

  5. Further investigations of plasma armature performance in the Culham Laboratory HTF rail launcher

    Herring, N.; Spikings, C. R.; Oxley, C. M.; Beacham, J. R.; Putley, D.


    This paper presents the results from an experimental investigation of plasma armature behavior in the Culham Laboratory HTF rail launcher. The object of this work was to gain further insight into the conditions which lead to the formation of secondary plasma arcs in the rail launcher. The railgun was operated with a 1 cm square bore formed from glass reinforced epoxy insulators and either stainless steel or copper rails. A 1 MJ, 8 kV capacitor bank was used as the power supply; this was arranged in five 200 kJ modules. The modules were sequentially fired, to produce a current waveform approximating to a linear ramp in the railgun. B-dot probes were used to measure the behavior of the plasma armatures in the launcher. A number of calibration checks were performed to assess the quality of the B-dot probe measurements, with regard to both spatial resolution and rail current measurement. Experimental results were obtained with projectile muzzle velocities ranging from 1.5 km/s to 3.0 km/s, two free arc shots also occurred during the test series. The results show that the launcher performed much better with copper rails than with stainless steel rails. The results also show that the glass epoxy insulators performed much better than the acetyl copolymer material previously used in HTF.

  6. Flow of granular matter in a silo with multiple exit orifices: Jamming to mixing

    Kamath, Sandesh; Kunte, Amit; Doshi, Pankaj; Orpe, Ashish V.


    We investigate the mixing characteristics of dry granular material while draining down a silo with multiple exit orifices. The mixing in the silo, which otherwise consists of noninteracting stagnant and flowing regions, is observed to improve significantly when the flow through specific orifices is stopped intermittently. This momentary stoppage of flow through the orifice is either controlled manually or is chosen by the system itself when the orifice width is small enough to cause spontaneous jamming and unjamming. We observe that the overall mixing behavior shows a systematic dependence on the frequency of closing and opening of specific orifices. In particular, the silo configuration employing random jamming and unjamming of any of the orifices shows early evidence of chaotic mixing. When operated in a multipass mode, the system exhibits a practical and efficient way of mixing particles.

  7. About Armature Winding and Armature Circuit of DC Motor Circular Current Problem(Part 1)%关于直流电动机的电枢绕组及电枢电路(一)环流问题

    王宗培; 陈敏祥


    The new DC motor (New DCM) shares the same armature winding with traditional DC motor (DCM) , all adopt seal connection (namely polygon connection) to combine K commutating units, the armature winding of New DCM is similar but are different with multi-phase AC motor's armature winding which employ typical polygon connection. New DCM is neither multi-phase AC motor nor multi-phase BLDCM. Multi-phase AC armature winding adopted typical polygon connection can have circular current in closed circuit. However, New DCM or DCM with seal connection armature winding will not and can not have circular current in closed circuit.%新直流电动机(New DCM)与传统有刷直流电动机(DCM)有相同的电枢绕组,都是分成K个换向单元成封闭形(多边形)接法,与多相交流电动机采取封闭形(多边形)接法的电枢绕组有类似之处但有区别,New DCM不是一台多相交流电动机,也不是一台多相无刷直流电动机.与典型多边形接法的多相交流电枢绕组闭合回路可能有环流的情况不同,New DCM或DCM为封闭形接法的电枢绕组,闭合回路内不存在环流,不可能产生环流.

  8. Performance predictions for electromagnetic launching with multi-fibre solid brush armatures and resistively layered rail accelerators

    Schoolderman, A.J.


    In the literature on EML research, a number of proposals have been made to suppress the negative influence of the velocity skin effect on the performance of solid armatures during electromagnetic launch. In this paper, the results of a study of two of these methods, i.e. the application of multi-fib

  9. A Study on Effects on Current Density Distribution, Inductance Gradient, and Contact Force by Variation of Armature and Rail Structure

    Kim, Bok Ki [Kwangwoon University, Seoul (Korea)


    The distribution of current in the conductors influenced by armature geometry and velocity is an important parameter for determining performance of an electromagnetic launcher(EML). The electric current in the early launching stage tends to flow on the outer surface of the conductors, resulting in very high local electric current density. However, the tendency for current to concentrate on the surface is driven by the velocity skin effect later in launching stage. The high current density produces high local heating and, consequently, increases armature wear which causes several defects on EML system. This paper investigates the effect of rail/armature geometry on current density distribution, launcher inductance gradient (L'), and contact force. Three geometrical parameters are used to characterize the railgun system. These are the ratio of contact length, relative position of contact leading edge to root trailing edge, and the ratio of rail overhang to the rail height. The distribution of current density, L',contact force between various configurations of the armature and the rail are analyzed and compared by using the EMAP3D program. (author). 6 refs., 9 figs., 3 tabs.

  10. Numerical simulation of scouring funnel in front of bottom orifice

    XUE Wan-yun; HUAI Wen-xin; Li Zhi-wei; Zeng Yu-hong; QIAN Zhong-dong; Yang Zhong-hua


    The scouring funnel in from of a bottom orifice under the condition of fixed water levels is simulated by using an Eulerian two-phase model,with onsideration of the flow-particle and particle-particle interactions.The predictions of the scouting funnel shape agree well with laboratory measurements.The flow-field characteristics of the two phases and the influences of the hydraulic and geometric parameters on the shape of the scouring funnel are analyzed on the basis of the computation results.It is revealed that the non-dimensional maximum scour hole parameters,the depth dm / do,the length lm / do,and the half-width wm / do,are linear with the densimetric Froude number Fro,the main parameter describing the scour hole,the centerline scour depth Dc and the half-scour width Wr vary according to a power law,and the transverse scour profiles exhibit strong similarities,the velocity distribution of the water is confined within the sink-like area near the orifice,and the mutual impact of the flows at the azimuthal sections and the resistances of the walls and the sand layer produce a vortex in the scour hole,that makes the sand particles to be suspended in the water,the exchanging water in the pore water is the main contributor in forcing the sand to move,and transporting the sand in the same direction as the pore water along azimuthal sections.

  11. Pulsating-flow measurement with an orifice flange

    Bossart, L. M.


    A measurement problem encountered during instrumentation of a geothermal air drilling operation on the Baca Ranch in the Jemez Mountains in New Mexico was how to measure the flow of ammonia water solution injected into the air line. The pump that develops the pressure in the ammonia line is not a positive displacement pump, therefore, counting pump strokes does not determine the number of gal/min of ammonia flow. The flow was measured using an orifice flange differential pressure technique but, the range of flow measured, exceeded the 4:1 range ability of an orifice. A computer smoothing of the differential pressure and the line pressure together with a scaling factor, determined by the shape of the raw differential pressure, provided a smoothing of the flow data which was checked against the actual flow over a long time period to determine the volume of solution injected into the system per hour. An instantaneous reading of ammonia flow was thereby determined. It showed small variations in corrosion rate measured in the standpipe that may have been caused by a momentary variation in the flow of ammonia solution.

  12. Robotics for Natural Orifice Transluminal Endoscopic Surgery: A Review

    Xiaona Wang


    Full Text Available Natural Orifice Transluminal Endoscopic Surgery (NOTES involves accessing the abdominal cavity via one of the bodies’ natural orifices, for example, mouth, anus, or vagina. This new surgical procedure is very appealing from patients’ perspectives because it eliminates completely abdominal wall aggression and promises to reduce postoperative pain, in addition to all other advantages brought by laparoscopic surgery. However, the constraints imposed by both the mode of access and the limited technology currently available make NOTES very challenging for the surgeons. Redesign of the instruments is imperative in order to make this emerging operative access safe and reproducible. In this paper, we survey on the state-of-the-art devices used in NOTES and introduce both the flexible instruments based on improvement of current endoscopic platforms and the revolutionary concept of robotic platforms based on the convergence of communication and micromechatronics technologies. The advantages and limitations of each category are addressed. Potential solutions are proposed to improve the existing designs and develop robust and stable robotic platforms for NOTES.

  13. A novel, new robotic platform for natural orifice distal pancreatectomy.

    Thakkar, Shyam; Awad, Michael; Gurram, Krishna C; Tully, Steven; Wright, Cornell; Sanan, Siddharth; Choset, Howie


    Laparoendoscopic technology has revolutionized the practice of surgery; however, surgeons have not widely accepted laparoscopic techniques for pancreatic surgeries due to the complexity of the operation. Natural orifice transluminal endoscopic surgery (NOTES) offers a great new potential for pancreatic procedures, with early data showing benefits of reduced visible scarring and the potential for decreased wound infections, hernias, pain, and postoperative complications. However, there are significant limitations to the currently used flexible endoscopy tools, including a diminished visual field, spatial orientation and tissue manipulation issues, and 2-dimensional visual feedback. We have adopted a novel snake-like robot, the minimally invasive cardiac surgery (MICS) robot, which addresses these issues. In the current pilot study, the MICS robot was evaluated for transrectal distal pancreas exploration and resection in 2 nonsurvival porcine models. Abdominal navigation and accessing the pancreas was investigated in the first pig, and based on its success, pancreas resection was studied in pig 2. The MICS robot was successful in accessing and visualizing the right upper, left upper, and left lower quadrants of the abdomen in pig 1 and was able to perform a successful complex NOTES procedure with distal pancreas resection in pig 2, with only minimal laparoscopic retraction assistance. In conclusion, preliminary results showing the MICS robot in natural orifice distal pancreatectomy are positive. Enhancements to optics and instrumentation will help further increase the usability in pancreatic interventions. Future indications may include transgastric NOTES approaches, endoluminal procedures, and single-port applications.

  14. Analysis of structural dynamic characteristics of armature in electrodynamic shaker%电动振动台动圈的结构动态特性分析

    崔志磊; 王金娥; 夏天凉


    In order to improve the performances of the electrodynamic shaker armature, the finite element model of the armature was established and the boundary conditions were defined. By means of computing the armature modes of different orders, its dynamic characteristics. With the aid of the modals analysis, the first axial modal of the armature were obtained, and the validity were analyzed, so that its first-order axial resonance frequency was obtained and verified by test. The result showed that the structure and material of the armature would decide the magnitude of that resonance frequency, and the larger the specific rigidity of the armature material. This could be done by adding reinforcing ribs to the armature.%为了提高电动振动台的工作性能,建立电动振动台动圈的有限元模型,确立其边界条件,通过计算动圈的各阶模态,分柝其动态特性,获得动圈的一阶轴向共振频率并进行实验验证.结果表明,动圈的结构及材料决定动圈一阶轴向共振频率的高低,动圈所选材料的比刚度越大越好;加强筋可以增强动圈的刚性.

  15. Theoretical and numerical study of hydraulic characteristics of orifice energy dissipator



    Full Text Available Different factors affecting the efficiency of the orifice energy dissipator were investigated based on a series of theoretical analyses and numerical simulations. The main factors investigated by dimension analysis were identified, including the Reynolds number (Re, the ratio of the orifice diameter to the inner diameter of the pipe ( , and the ratio of distances between orifices to the inner diameter of the pipe ( . Then, numerical simulations were conducted with a two-equation turbulence model. The calculation results show the following: Hydraulic characteristics change dramatically as flow passes through the orifice, with abruptly increasing velocity and turbulent energy, and decreasing pressure. The turbulent energy appears to be low in the middle and high near the pipe wall. For the energy dissipation setup with only one orifice, when Re is smaller than 105, the orifice energy dissipation coefficient K increases rapidly with the increase of Re. When Re is larger than 105, K gradually stabilizes. As increases, K and the length of the recirculation region L1 show similar variation patterns, which inversely vary with . The function curves can be approximated as straight lines. For the energy dissipation model with two orifices, because of different incoming flows at different orifices, the energy dissipation coefficient of the second orifice (K2 is smaller than that of the first. If is less than 5, the K value of the model, depending on the variation of K2, increases with the spacing between two orifices L , and an orifice cannot fulfill its energy dissipation function. If is greater than 5, K2 tends to be steady; thus, the K value of the model gradually stabilizes. Then, the flow fully develops, and L has almost no impact on the value of K.

  16. Acoustical characteristics of two-phase horizontal intermittent flow through an orifice

    Lee, J.S.; Violato, D.; Polifke, W.


    This study addresses acoustical characteristics, in particular, sound generation of intermittent flow regime in a horizontal pipe through an orifice, based on recorded pressure fluctuations and videos of upstream and downstream flow of the orifice. The flow regimes of interest are plug flow and slug

  17. Natural orifice translumenal endoscopic surgery (NOTES): current status and challenges

    ZHANG Xiu-li; YANG Yun-sheng; SUN Gang; GUO Ming-zhou


    Objective To give a conceptual description of natural orifice translumenal endoscopic surgery (NOTES), review theearly efforts in the NOTES field, and discuss its challenges and limitations.Data sources The data were retrieved mainly from publications listed in MEDLINE, PubMed and China WanfangDatabase from 2005 to 2009. The search term was "NOTES". Study selection The articles involved in the "NOTES" study were selected and the review articles were excluded from the comparison. Results A marked increase in quantity in articles was shown each year for NOTES studies from 2006 to 2009. Animalexperiments with "NOTES" have been carried out in China from 2007, and two independent "NOTES" procedures onhumans were reported in 2009. Conclusion Although still in its infancy, the "NOTES" procedure is promising as another type of minimally invasivesurgery and favorable alternative to current interventions.

  18. Features of the Viscous Fluids Effluent Through Non-round Shape Edge Orifices

    V. N. Pil'gunov


    Full Text Available The knowledge of features of viscous fluid effluent through the sharp-edged orifices and nozzles is necessary when calculating the heat engine fuel feed systems, device designs of chemical production, as well as in designing the components of hydraulic actuators and hydraulic control systems.Process of fluid effluent through the round shape orifices is rather well studied: in technical publications experimental values of fluid effluent coefficients and their dependence on Reynolds's number are widely presented. The process of fluid effluent through the sharp-edged nonround shape orifices is a little studied, and there is no quantitative assessment of the orifice shape influence on the fluid effluent coefficients. This work to some extent fills shortage of information in issue under consideration.As an object of study, conditionally sharp-edged equilateral, triangular, square, rectangular, and crosswise orifices were chosen. The inversion process effects on the shape of stream outflowing through the non-round orifice: this process is caused by interaction of surface tension force, aiming to minimize the external surface area of a stream, and force of inertia aimed at momentum conservation of the fluid particle mass being on the trajectory of an elementary stream. Unevenness of field of radial stream rates leaking towards the orifice has essential impact on the shape of the inverted stream.To raise a flow rate capacity of the non-round shape orifices, was used an external tubular non-expanding nozzle representing a short pipe section the length of which is about three - four diameters of the orifice. Control of the absolute pressure value in the camera of open external tubular non-expanding nozzle with a triangular intake orifice allows us to change its flow rate capacity in the certain, rather narrow range. Pressure in the camera of tubular non-expanding nozzle was changed through its regimented opening to atmosphere using an adjustable precision

  19. Research on LVDT Displacement Sensor with Built-in Return Spring%一种内置复位弹簧式位移传感器的研制

    李沛剑; 蒋晓彤; 郑浩


    针对机械反馈伺服作动器测试零位输出不稳定,测得位移量与实际测量长度存在误差等问题,原有的传统LVDT式位移传感器不能满足高精度测试需求,采用内置复位弹簧设计的新型位移传感器消除了连接部位间隙,提高了测试可靠性。%For mechanical feedback servo actuator to test the zero output is unstable, the errors are existed between the measured amount of displacement and the length of actual measurement. The original traditional LVDT displacement sensor can not meet the demanding for high-accuracy test. The joints gap is eliminated when using the new displacement sensor with built-in return spring and the test reliability is improved at the same time.

  20. Modeling and Parameter Identification of the Vibration Characteristics of Armature Assembly in a Torque Motor of Hydraulic Servo Valves under Electromagnetic Excitations

    Jinghui Peng


    Full Text Available The resonance of the armature assembly is the main problem leading to the fatigue of the spring pipe in a torque motor of hydraulic servo valves, which can cause the failure of servo valves. To predict the vibration characteristics of the armature assembly, this paper focuses on the mathematical modeling of the vibration characteristics of armature assembly in a hydraulic servo valve and the identification of parameters in the models. To build models more accurately, the effect of the magnetic spring is taken into account. Vibration modal analysis is performed to obtain the mode shapes and natural frequencies, which are necessary to implement the identification of damping ratios in the mathematical models. Based on the mathematical models for the vibration characteristics, the harmonic responses of the armature assembly are analyzed using the finite element method and measured under electromagnetic excitations. The simulation results agree well with the experimental studies.

  1. Analysis of armature reaction and winding inductances of permanent magnet brushless DC motor with deep slot concentrated coils

    HUANG Ping-lin; HU Qian-sheng; YU Li; HUANG Yun-kai


    Based on the configuration of deep slot concentrated coils,an analytical model is developed for predicting the armature reaction field produced by the 3-phase stator windings of permanent magnet brushless DC motors with concentrated coils by using the image method and the analytical functions of the armature reaction and winding inductances are proposed accounting for the influence of statot slotting.This approach is different from the method of equivalent distributed current sheet and more suitable for electric machines,which have concentrated coils and deeper slots.Under different control mode,the different analytical functions are presented.This will be helpful when further analyzing the performance of the motor.The results agree with the experiment very well.

  2. Investigation of Tungsten, Copper, and Silver Alloys with Indium at the Rail-Armature Interface on a Railgun Test Bench


    major challenges facing electromagnetic launch (EMIL) railguns is the degradation of the rail and armature during firing. This degradation is a railgun by providing enough current to fire the projectile. During phase 11 the capacitor voltage was reduced, and materials were investigated at...Scientific Company, 1968 9. Lockwood, M., Design and Construction of an Expandable Series Trans-Augmented Electromagnetic Railgun , Master’s Thesis, Naval

  3. Mechanics of sequential jamming and unjamming phenomena in a multi-exit orifice silo

    Kunte, Amit; Orpe, Ashish; Doshi, Pankaj


    We have investigated the flow of a two dimensional granular assembly draining through a flat bottomed silo having multiple exit orifices using DEM simulations. The width of the central orifice of the silo is fixed at 3 . 5 d which is small enough to cause jamming (or no-flow) through the orifice. Here d is the mean particle diameter. The width of the other nearby orifices is kept much more than 3 . 5 d , thus, ensuring continuous flow of particles through them. Interestingly, this continuous flow of particles in the vicinity interacts with the assembly of jammed particles above the central orifice causing rearrangements and ultimately unjamming the assembly leading to a smooth flow. During the entire drainage of the silo, the central orifice undergoes this sequence of jamming-unjamming event several times, the frequency of which depends on its proximity to the nearby orifices. We focus primarily on understanding this jamming-unjamming transition by investigating the contact force network and the normal force distributions. Our preliminary results show that the tails of the force distributions in the jammed region decay slower than those for the flowing regions. This qualitative behaviour is found to be independent of any prior rearrangement history. Department of Science and Technology, India, (Grant No. SR/S3/CE/037/2009).

  4. Three dimensional structural insight of laser drilled orifices in osmotic pump tablets.

    Wu, Li; Wang, Lebing; Wang, Shuxia; Xiao, Tiqiao; Chen, Min; Shao, Qun; York, Peter; Singh, Vikaramjeet; Yin, Xianzhen; Gu, Jingkai; Zhang, Jiwen


    The orifice drilled in the membrane as a channel for drug delivery is the key functional part of the osmotic pumps for a controlled drug release system. Reported conventional microscopic evaluations of these orifices have been limited to measurement of two-dimensional cross-section diameters. This study was aimed at establishing a novel method to measure quantitatively the three-dimensional architectures of orifices based on synchrotron radiation X-ray microcomputed tomography (SR-μCT). Quantitative analysis of architectures extracted from captopril osmotic pumps drilled by a range of operating parameters indicated that laser power correlated with the cross section area, volume, surface area and depth of the orifices, while scanning speed of laser beam showed inverse relationships with the above structure characters. The synchrotron radiation based Fourier transform infrared microspectroscopy mapping showed that there was no apparent chemical change in the surrounding area of the orifice compared with the normal membrane region. Thus SR-μCT was successfully applied to marketed felodipine osmotic pumps for architectural evaluation of the orifices. In conclusion, the first three-dimensional structural insight of orifices in osmotic pump tablets by SR-μCT and structural reconstruction for the architectures has provided deeper insight into improving the design of advanced osmotic pumps for controlled drug release.

  5. Subsonic tests of an all-flush-pressure-orifice air data system

    Larson, T. J.; Siemers, P. M., III


    The use of an all-flush-pressure-orifice array as a subsonic air data system was evaluated in flight and wind tunnel tests. Two orifice configurations were investigated. Both used orifices arranged in a cruciform pattern on the airplane nose. One configuration also used orifices on the sides of the fuselage for a source of static pressure. The all-nose-orifice configuration was similar to the shuttle entry air data system (SEADS). The flight data were obtained with a KC-135A airplane. The wind tunnel data were acquired with a 0.035-scale model of the KC-135A airplane. With proper calibration, several orifices on the vertical centerline of the vehicle's nose were found to be satisfactory for the determination of total pressure and angle of attack. Angle of sideslip could be accurately determined from pressure measurements made on the horizontal centerline of the aircraft. Orifice pairs were also found that provided pressure ratio relationships suitable for the determination of Mach number. The accuracy that can be expected for the air data determined with SEADS during subsonic orbiter flight is indicated.

  6. Design and Range of Application of Slot Bushings with Volumetric Orifice Fields



    A design of a slot bushing with a volumetric field has been developed,which allows to produce continuous fibers from melts with difficult processing characteristics in order to produce fibers with better operating characteristics.The operability of the design was confirrned when solving two problems of special technological complexity.1.400- and 800-orifice bushings for production of continuous fibers from the basalt melt have been developed and recommended for manufacture.2.The process of production of continuous fibers from standard glass using 2400-orifice bushing with perforated plates instead of orifice tips without air cooling,has been realized for the first time.

  7. Boundary layer suction through rectangular orifices: effects of aspect ratio and orientation

    Van Buren, T.; Smits, A. J.; Amitay, M.


    The flow field generated by suction through a rectangular orifice within a laminar boundary layer is investigated using stereoscopic particle image velocimetry. For orifice aspect ratios of 6, 12, and 18, the impact of suction on the surrounding flow field appears to be self-similar, scaling with aspect ratio and suction velocity. Changing the orifice pitch angle had almost no impact on the surrounding boundary layer, but, as expected, changing the skew angle significantly altered the extent of the suction impact on the flow field.

  8. Nonlinear Bubbling and Micro-Convection at a Submerged Orifice


    The present paper describes the nonlinear behavior of bubble formation from a single submerged orifice and induced liquid motion (micro-convection) surrounding the bubble. The experimental data reveals that departing periods of successive bubbles evolve multiple periods from single to triple periods when the gas flow rate is increased and that the micro-convection evolves bifurcation phenomena similar to the so-called "period doubling" in chaos dynamics. The photographic observation using high-speed video movies and data analysis indicate that the nonlinear features come from the deformation of the bubble and also the interaction between consecutive bubbles. A new comprehensive theoretical model is developed for describing the instantaneous bubble behaviors during formation and ascendance processes and for predicting the departing periods and sizes of successive bubbles for constant flow rate conditions. Owing to the estimation of instantaneous interactions between successive bubbles and the incorporation of the wake effect of previous bubbles, the present model describes the evolution process and mechanisms of bubble departing periods corresponding to different gas flow rate regimes. The theoretical results are in good agreement with experimental results.

  9. Novel Design of Orifice Type Control Element for Mitigating Instabilities Project

    National Aeronautics and Space Administration — An orifice element is commonly used in liquid rocket engine test facilities either as a flow metering device, or to provide a large reduction in pressure over a very...

  10. Novel Design of Orifice Type Control Element for Mitigating Instabilities Project

    National Aeronautics and Space Administration — An orifice element is commonly used in liquid rocket engine test facilities to provide a large reduction in pressure over a very small distance in the piping system....

  11. The whistling potentiality of an orifice in a confined flow using an energetic criterion

    Testud, P.; Aurégan, Y.; Moussou, P.; Hirschberg, A.


    Using a two-source method, the scattering matrices of 10 sharp-edged thin orifices are measured under different subsonic flow conditions. The data are analysed in terms of net acoustical energy balance: the potential whistling frequency range is defined as the one associated with acoustical energy production. A Strouhal number describing the maximum whistling potentiality is found to be equal to 0.2-0.35, based on the orifice thickness and the orifice jet velocity. It appears to depend on the Reynolds number and on the ratio of orifice to pipe diameters. Tests are performed to compare theoretically and experimentally the potential whistling frequency to the actual whistling frequency. They are found to coincide within the measurement uncertainty.

  12. Assessing transgastric Natural Orifice Transluminal Endoscopic Surgery prior to clinical implementation

    Donatsky, Anders Meller


    The objective was to investigate whether transgastric Natural Orifice Transluminal Endoscopic Surgery (NOTES) could be implemented safely in clinical practice. The experimental studies proved ultrasonography guided access through the stomach to be feasible and safe without iatrogenic complication...

  13. Spray pattern analysis for metered dose inhalers I: Orifice size, particle size, and droplet motion correlations.

    Smyth, H; Hickey, A J; Brace, G; Barbour, T; Gallion, J; Grove, J


    Factors that influence spray pattern measurements of pressurized, metered-dose inhalers have been evaluated. Spray patterns were correlated with changes in actuator orifice diameter, particle size profiles, and calculated estimates of particle-size dynamics of plumes during a spray. Spray patterns, regardless of actuator orifice size, were ellipsoid in the vertical direction. Measures of elliptical ratio, major axis, and minor axis were significantly influenced by orifice size in a non-linear fashion over the range of orifice sizes investigated. Spray patterns also correlated with particle size profile and spray geometry measurements. Spray distribution asymmetry may be related to droplet evaporation and sedimentation processes. However, the spray patterns did not appear sensitive to changes in gravitational force acting on the plume. Instead, it is postulated that elliptical spray patterns may have dependence on fluid dynamic processes within the inhaler actuator. Developing an understanding of these processes may provide a basis for developing spray pattern tests with relevance to product performance.

  14. [Fourth branchial cleft deformity with skin orifice: a series of 10 cases].

    Huang, S L; Zhang, B; Chen, L S; Liang, L; Luo, X N; Lu, Z M; Zhang, S Y


    Objective: To report rare cases of congenital neck cutaneous sinus with an orifice near the sternoclavicular joint and to investigate their origins and managements. Methods: A total of ten patients with congenital neck cutaneous sinus having an orifice near the sternoclavicular joint treated in the Guangdong General Hospital from January 2010 to June 2015 were retrospectively analyzed. Results: There four boys and six girls, aging from 11 months to 96 months with an average of 33.4 months, and they had a common feature showing a congenital cutaneous sinus with an orifice near sternoclavicular joint. Discharge of pus from the orifice or abscess formation was commonly seen soon after infection. With bacteriological study, staphylococcus aureus was positive in five cases and klebsiella pneumonia in a case. Another orifice of fistula/sinus was not depicted in pyriform with barium swallow X-ray in five cases Ultrasound studies of three cases demonstrated anechoic (i.e., nearly black) and solid-cystic lesion near sternoclavicular joint with posterior acoustic enhancement. Magnetic resonance imaging (MRI) showed isointensity of the lesion on T1 and T2 weighted images with heterogeneous enhancement and a close relationship with sternoclavicular joint. All patients underwent laryngoscopic examination, which showed no orifice of sinus in pyriform at same side. Surgical resection of fistula/sinus was performed in all cases. The lengths of the fistula varied from 5 mm to 22 mm with an average of 11 mm. Postoperative pathological examination showed all specimens were accordance with fistula. No complications were noticed. Recurrence was not observed in the cases by following-up of 6 months to 70 months (median: 33 months). Conclusion: Congenital neck cutaneous sinus with orifice near the sternoclavicular joint maybe a special clinical phenotype of the fourth branchial cleft sinus with skin orifice in cervicothoracic junction. Differential diagnoses between low cervical diseases

  15. Orifice sizes for K-reactor fringe zones with I&E fuel

    Waters, E.D.; Calkin, J.F.


    The purpose of this report is to describe orifice combinations which can be utilized in Zone 2, 3, and 4 of the K Reactors while using K-IV I&E fuel elements and to present working data to describe the calibration and.critical flow characteristics of initial prototypes of these orifice combinations. A discussion is included concerning the minimum flow rates attainable by front face orificing while avoiding critical flow conditions.

  16. Small-Scale Spray Releases: Orifice Plugging Test Results

    Mahoney, Lenna A.; Gauglitz, Phillip A.; Blanchard, Jeremy; Kimura, Marcia L.; Kurath, Dean E.


    One of the events postulated in the hazard analysis at the Waste Treatment and Immobilization Plant (WTP) and other U.S. Department of Energy (DOE) nuclear facilities, is a breach in process piping that produces aerosols with droplet sizes in the respirable range. The current approach for predicting the size and concentration of aerosols produced in a spray leak involves extrapolating from correlations published in the literature. These correlations are based on results obtained from small engineered spray nozzles using pure liquids with Newtonian fluid behavior. The narrow ranges of physical properties on which the correlations are based do not cover the wide range of slurries and viscous materials present in the WTP and across processing facilities in the DOE complex. Two key technical areas were identified where testing results were needed to improve the technical basis by reducing the uncertainty introduced by extrapolating existing literature results. The first technical need was to quantify the role of slurry particles in small breaches in which the slurry particles may plug and result in substantially reduced, or even negligible, respirable fraction formed by high pressure sprays. The second technical need was to determine the aerosol droplet size distribution and volume from prototypic breaches and fluids, specifically including sprays from larger breaches with slurries where data from the literature are largely absent. To address these technical areas, small- and large-scale test stands were constructed and operated with simulants to determine the aerosol release fractions and aerosol generation rates from a range of breach sizes and geometries. The properties of the simulants represented the range of properties expected in the WTP process streams and included water, sodium salt solutions, slurries containing boehmite or gibbsite, and a hazardous chemical simulant. The effect of anti-foam agents (AFA) was assessed with most of the simulants. Orifices

  17. Noise generated by cavitating single-hole and multi-hole orifices in a water pipe

    Testud, P.; Moussou, P.; Hirschberg, A.; Aurégan, Y.


    This paper presents an experimental study of the acoustical effects of cavitation caused by a water flow through an orifice. A circular-centered single-hole orifice and a multi-hole orifice are tested. Experiments are performed under industrial conditions: the pressure drop across the orifice varies from 3 to 30 bar, corresponding to cavitation numbers from 0.74 to 0.03. Two regimes of cavitation are discerned. In each regime, the broadband noise spectra obtained far downstream of the orifice are presented. A nondimensional representation is proposed: in the intermediate ‘developed cavitation’ regime, spectra collapse reasonably well; in the more intense ‘super cavitation’ regime, spectra depend strongly on the quantity of air remaining in the water downstream of the orifice, which is revealed by the measure of the speed of sound at the downstream transducers. In the ‘developed cavitation’ regime, whistling associated with periodic vortex shedding is observed. The corresponding Strouhal number agrees reasonably well with literature for single-phase flows. In the 'super cavitation’ regime, the whistling disappears.

  18. Pressure Drop Control Using Multiple Orifice System in Compressible Pipe Flows

    Heuydong Kim; Toshiaki Setoguchi; Shigeru Matsuo; S. R. Raghunathan


    In order to investigate the effectiveness of an orifice system in producing pressure drops and the effect of compressibility on the pressure drop, computations using the mass-averaged implicit Navier-Stokes equations were applied to the axisymmetric pipe flows with the operating pressure ratio from 1.5 to 20.0. The standard k- ε turbulence model was employed to close the governing equations. Numerical calculations were carried out for some combinations of the multiple orifice configurations. The present CFD data showed that the orifice systems,which have been applied to incompressible flow regime to date, could not be used for the high operating pressure ratio flows. The orifice interval did not strongly affect the total pressure drop, but the orifice area ratio more than 2.5 led to relatively high pressure drops. The total pressure drop rapidly increased in the range of the operating pressure ratio from 1.5 to 4.0, but it nearly did not increase when the operating pressure ratio was over 4.0. In the compressible pipe flows through double and triple orifice systems, the total pressure drop was largely due to shock losses.

  19. Effect of Orifice Diameter on Bubble Generation Process in Melt Gas Injection to Prepare Aluminum Foams

    Yuan, Jianyu; Li, Yanxiang; Wang, Ningzhen; Cheng, Ying; Chen, Xiang


    The bubble generation process in conditioned A356 alloy melt through submerged spiry orifices with a wide diameter range (from 0.07 to 1.0 mm) is investigated in order to prepare aluminum foams with fine pores. The gas flow rate and chamber pressure relationship for each orifice is first determined when blowing gas in atmospheric environment. The effects of chamber pressure ( P c) and orifice diameter ( D o) on bubble size are then analyzed separately when blowing gas in melt. A three-dimensional fitting curve is obtained illustrating both the influences of orifice diameter and chamber pressure on bubble size based on the experimental data. It is found that the bubble size has a V-shaped relationship with orifice diameter and chamber pressure neighboring the optimized parameter ( D o = 0.25 mm, P c = 0.4 MPa). The bubble generation mechanism is proposed based on the Rayleigh-Plesset equation. It is found that the bubbles will not be generated until a threshold pressure difference is reached. The threshold pressure difference is dependent on the orifice diameter, which determines the time span of pre-formation stage and bubble growth stage.


    Alexandre P. Svintsov


    Full Text Available One of the important tasks when designing the water fittings is to calculate the orifice area of locking pair for passing the calculated water flow at a calculated pressure. The method of determining the orifice area with smoothly changing shape based on the piecewise-element method is proposed. This method is characterized by a comparative simplicity and sufficient accuracy for engineering calculations to determine the orifice area of the disk type locking pairs for the valve head. The proposed method allows us to determine the required size of the orifice area for passing the calculated water flow and also to determine the water flow rate depending on the opening level of orifice. The authors carried out the necessary calculations and manufactured ceramic disk type locking pairs by using the proposed method. Bench tests of water fittings with valve heads those are having orifices with smoothly changing shapes (in the form of bent blob showed that water flow is changing almost in proportional to the tap opening. This method can be used not only for the designing of the water fittings and also for the shut-off valves of various purposes.

  1. Overcome side identification in PPOP by making orifices on both layers.

    Zhang, Zhi-hong; Li, Wei; Nie, Shu-fang; Tang, Xin; Peng, Bo; Tian, Lei; Pan, Wei-san


    The original purpose of this research was to build a database for an expert system. Unexpectedly, it was found that the color-identifying device in push-pull osmotic pump (PPOP) manufacturing process could be unnecessary. Water-insoluble drug indapamide, gliclazide and dipyridamole were employed as model drugs. Bunches of conventional formulations were designed; and traditional preparation procedures were used. In vitro drug release was studied; and the similarity between the conditions of orifice only on the side of the drug layer and orifices of the same diameter on both sides was evaluated. It was found that the drug release from PPOP could be influenced by formulation and core hardness while it could hardly be influenced by orifice size. No significant difference was observed between the dissolution profiles of orifice only on the side of the drug layer and orifices of the same diameter on both sides. Mechanism of drug release was discussed. The conclusion was that the disadvantage of side identification in PPOP manufacturing process could be overcome by drilling orifices on both sides.

  2. Cross and clover shaped orifice jets analysis at low Reynolds number

    Meslem Amina


    Full Text Available The jet coming from a cross-shaped orifice with an open center has been shown in the past, to provide substantial increase in the near field convective transport-mixing, in comparison to a classical round orifice jet. Detailed information has been reported in previous works on the role played in the jet mixing enhancement by the crow of vortices composed of counter-rotating pairs of secondary streamwise structures which are developing in orifice’s troughs. A trough in the cross-shaped jet generates a local shear like the one generated by a triangular tab in a square jet. In the present study we are interested by the modification of local shears in the troughs of the cross-shaped jet, when orifice geometry is modified, such as the center of the orifice becomes closed, leading to a clover-shaped orifice. The general motivation is to understand the effect of using a set of combination of longitudinal structures, themselves produced by the superposition of local shear regions, in mixing performance of a cross jet. It is shown that lower entrainment rates in the clover jet is a results of a additional internal crown of vortices which opposes the external one due to inner shears generated by closing the center of the orifice.

  3. Video. Pure natural orifice transluminal endoscopic surgery (NOTES) cholecystectomy.

    Bessler, Marc; Gumbs, Andrew A; Milone, Luca; Evanko, John C; Stevens, Peter; Fowler, Dennis


    Enthusiasm for natural orifice transluminal endoscopic surgery (NOTES) has been partly tempered by the reality that most NOTES procedures to date have been laparoscopically assisted. After safely performing transvaginal cholecystectomy in an IACUC-approved porcine model, the authors embarked on an institution review board (IRB)-approved protocol for ultimate performance of pure NOTES cholecystectomy in humans. They describe their experience performing a true NOTES transvaginal cholecystectomy after safely accomplishing three laparoscopically assisted or hybrid procedures in humans. One of the patients was a 35-year-old woman presenting with symptoms of biliary colic. Ultrasound confirmed gallstones, and her liver enzymes were normal. Pneumoperitoneum to 15 mmHg was obtained via a transvaginal trocar placed through a colpotomy made under direct vision. A double-channel endoscope then was advanced into the abdomen. To overcome the retracting limitations of currently available endoscopes, the authors used an extra-long 5-mm articulating retractor placed into the abdomen via a separate colpotomy made under direct vision using the flexible endoscope in a retroflexed position. Endoscopically placed clips were used for control of both the cystic duct and the artery. These techniques obviated the need for any transabdominally placed instruments or needles. This patient was the first to undergo a completely NOTES cholecystectomy at the authors' institution, and to their knowledge, in the United States. She was discharged on the day of surgery and at this writing has not experienced any complication after 1 month of follow-up evaluation. Performance of NOTES transvaginal cholecystectomy without aid of laparoscopic or needleoscopic instruments is feasible and safe for humans. Additional experience with this technique are required before studies comparing it with standard laparoscopy and hybrid techniques are appropriate.

  4. Lufthastighed langs gulvet i et lokale med vægmonteret armatur og fortrængningsventilation

    Nielsen, Peter V.

    Luften fra vægmonterede lavimpulsarmaturer strømmer ved fortrængningsventilation direkte ind i opholdszonen. Det er derfor vigtigt at kunne bestemme den lufthastighed, der opstår i forskellig afstand fra armaturet for at fastlægge den termiske komfort i lokalet. I det følgende viser en række måli...... målinger på tre forskellige armaturer nogle karakteristiske forhold ved strømningen. Med udgangspunkt i en dimensionsanalyse opstilles der et relativt enkelt formelsystem, som giver en kvantitativ beskrivelse af denne strømning....

  5. Ranchero Armature Test LA-19.4-CT-3: PBX-9501 Explosive with no smoothing layer. Firing point 88, 9/16/13

    Glover, Brian B. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Goforth, James H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rae, Philip John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dickson, Peter [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Briggs, Matthew E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Marr-Lyon, Mark [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hare, Steven John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Herrera, Dennis Harold [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Watt, Robert Gregory [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rousculp, Christopher L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    LA-19.4-CT-3 (CT-3) was the third camera test in a series beginning in 1/11, which diagnose the performance of 6 mm thick, 6061 T-0 Al Ranchero armatures. [The test LA-43-CT-2 (CT-2) is described in LA-UR-14-21983.] The goal of CT-3 was to verify that PBX-9501, with 18 mm point spacing and no smoothing layer, could be used for Ranchero generator armatures in place of PBXN-110, which had been used in all previous Ranchero applications. CT-1 and CT-2 both had 43 cm long slapper detonator systems imbedded in the cast PBXN-110 explosive, but manufacturing a charge for a similar 9501 test was not cost effective. Instead, a single cylinder of 9501, 19.368 cm long and 15.494 cm (6.100”)in diameter, had a groove machined to accommodate a row of 11 SE-1 detonators with 18 mm point spacing along the mid-plane of the cylinder. The expansion of the armature looks like a slapper assembly along almost ½ of the circumference, and provides adequate proof of concept. Removing the smoother from PBXN-110-driven armatures increased the armature velocity from 3.1 mm/μs to 3.3 mm/μs, as seen in CT-2, and the velocity measured on CT-3 increased to 3.8 mm/μs. In addition, the camera records show that the surface of the armature is smooth enough, and free from ruptures for an expansion of greater that 2X. The advantage of using 9501 is that it precludes concerns about blow-outs seen when bubbles are left in the cast material, and gives extra velocity. The disadvantage is that the machined explosives are more expensive.

  6. 浅谈单相串激电机电枢元件的借偏%On the Def lection of Single-Phase Series Motor Armature Element



    以电刷的放置原则为切入点,引出串激电机电枢元件的借偏概念,介绍电枢元件借偏大小判断的原理和基本步骤。%With the principle of placing the brush as a starting point, the concept of universal motor armature element def lection is pointed, and the principle and basic steps of armature elements def lection judgment is introduced.

  7. Discharge flow of granular media from silos with a lateral orifice and injection of air

    Aussillous Pascale


    Full Text Available Few studies concern the prediction of the mass flow rate of a granular media discharged from a silo with a lateral orifice. However, this situation can have pratical interest considering a tank of granular material with a leak on its side. We studied experimentally the discharge of a vertical silo filled by spherical glass beads. We consider rectangular silos with a rectangular orifice. The impact of size, aspect ratio and position of the orifice and the effect of an additional air flow were studied. The measured parameters are the mass flow rate and the pressure along the silo, whereas the controlled parameters are the size of particles, and the flow rate of air. We identified two regimes of discharge according to the aspect ratio (of width to height of the rectangular orifice. Increasing the air flow rate induces an increase of the granular media flow rate. Using a simple physical model to describe the grains and gas flow, we put in evidence the role played by the air pressure gradient at the outlet. Then we compared the experimental results with continuum Navier-Stokes simulations with the granular μ(I-rheology. We showed that the continuum μ(I-rheology describes well our discharge flow of granular media from silos, taking into account the effect of the position of the orifice as well as the coupling with the gas flow.

  8. Preventing noise caused by vortex shedding in gate valves and orifices

    Smith, B.A.W.; Luloff, B.V.; Tromp, J.H. [Atomic Energy of Canada Ltd., Chalk River, Ontario (Canada)


    Gate valves and high-energy orifices can both act as sources of noise. This noise can represent a simple environmental problem or, in severe cases, can cause piping failures within hours. This paper presents the results of two studies, one to eliminate noise in the main steam lines of a new reactor, and, the other, to develop design guidelines for preventing noise in multi-stage, high-energy orifices. Both the valves and orifices were found to have a common noise generation mechanism, namely, an unstable fluid shear layer (e.g., vortex shedding) coupled with a fluid-resonant condition (i.e., an acoustic resonance). The main steam line noise was round to be caused by periodic vortex shedding across the seat cavities of the main steam isolation valves. The orifice noise is thought to be due to vortex shedding within the orifice holes themselves. This paper reviews the findings of both studies and presents measures that can be taken to eliminate noise problems. (author)

  9. Neutron Imaging study of bubble behaviors in Nanofluid Through Engineered Orifices

    Seo, Seok Bin; Bang, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of); Kim, Tae Joo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)


    Most studies focused on the change of surface parameters through deposited nanoparticles, while Vafaei and Wen firstly discussed modification of bubble dynamics by dispersed nanoparticles in fluid as well as deposited ones. The boiling mechanism, as an effective heat transfer mode, includes bubble generation, growth, departure, and coalescence. Therefore the change of bubble dynamics can lead to the change of boiling heat transfer condition. That is, not only surface characteristics but the dispersed nanoparticles would be the essential parameters of boiling mechanism in terms of bubble dynamics. For advanced visualization of opaque fluids, the neutron imaging technique is introduced. In the present study, the bubble dynamics in nanofluid through engineered orifices was studied. The main parameters of engineered orifices are size and geometry. Photographic analysis of bubble departure frequency and averaged bubble departure volume provides as follows: With increasing orifice diameter, averaged bubble departure volume increases, while bubble departure frequency decreases. The results are attributed to enhanced capillary force by increasing contact perimeter. Averaged bubble departure volume and bubble departure frequency remain similar for three different types of orifices. But edges of the triangle and square orifice produce small bubbles which interrupts bubble generation. The converged triple contact line due to the edge may be a reason for the emerged baby bubbles. Nanofluid shows less averaged bubble departure volume and higher bubble departure frequency. Considering little change in physical properties of the fluid, interaction between bubble interface and nanoparticles may be in charge of the results.

  10. Acoustic Absorption Characteristics of an Orifice With a Mean Bias Flow

    Ahuja, K. K.; Gaeta, R. J., Jr.; DAgostino, M.; Jones, Mike (Technical Monitor)


    The objective of the study reported here was to acquire acoustic and flow data for numerical validation of impedance models that simulate bias flow through perforates. The impedance model is being developed by researchers at High Technology Corporation. This report documents normal incidence impedance measurements a singular circular orifice with mean flow passing through it. All measurements are made within a 1.12 inch (28.5 mm) diameter impedance tube. The mean flow is introduced upstream of the orifice (with the flow and incident sound wave travelling in the same direction) with an anechoic termination downstream of the orifice. Velocity profiles are obtained upstream of the orifice to characterize the inflow boundary conditions. Velocity in the center of the orifice is also obtained. All velocity measurements are made with a hot wire anemometer and subsequent checked with mass flow measurements made concurrently. All impedance measurements are made using the Two-Microphone Method. Although we have left the analysis of the data to the developers of the impedance models that simulate bias flow through perforate, our initial examination indicates that our results follow the trends consistent with published theory on impedance of perforates with a steady bias flow.

  11. Comparison of turbulent flow through hexagram and hexagon orifices in circular pipes using large-eddy simulation

    Wang, Wei; Nicolleau, Franck C G A; Qin, Ning, E-mail: [Department of Mechanical Engineering, The University of Sheffield, Sheffield, S1 3JD (United Kingdom)


    Characteristics of turbulent flow through a circular, a hexagon and a hexagram orifice with the same flow area in circular pipes are investigated using wall-modelled large-eddy simulation. Good agreements to available experimental data were obtained in both the mean velocity and turbulent kinetic energy. The hexagram orifice with alternating convex and concave corners introduces outwards radial velocity around the concave corners downstream of the orifice plate stronger than the hexagon orifice. The stronger outwards radial velocity transfers high momentum from the pipe centre towards the pipe wall to energize the orifice-forced vortex sheet rolling-up and leads to a delayed vortex break-down. Correspondingly, the hexagram has a more gradual flow recovery to a pipe flow and a reduced pressure drop than the hexagon orifice. Both the hexagon and hexagram orifices show an axis-switching phenomenon, which is observed from both the streamwise velocity and turbulent kinetic energy contours. To the best knowledge of the authors, this is the first comparison of orifice-forced turbulence development, mixing and flow dynamics between a regular and a fractal-based polygonal orifice. (paper)

  12. Double mitral valve orifice. Two-dimensional and Doppler echocardiographic diagnosis.

    Solorio, S; Badui, E; Yáñez, M; Enciso, R; Rodríguez, L; Quintero, L R


    The purpose of this study was to demonstrate the usefulness of two-dimensional and Doppler echocardiography for diagnosing double mitral valve orifices (DMVO) in addition to identifying associated pathologies. We report five cases, three male and two female with an age ranging from 4 to 44 years old (mean age: 17 years), with the diagnosis of DMVO according to the following characteristics: using two-dimensional echocardiography on the short parasternal axis, both orifices were observed; apical in which the "seagull sign" was identified in both chambers, in addition to identifying the flows of each orifice by pulsed and codified color Doppler obtaining the corresponding gradients. With respect to the associated pathologies, all patients presented some type of malformation, such as subaortic ring, patent ductus arteriosus, coarctation of the aorta, bicuspid aorta and pulmonary stenosis. Using the color Doppler echocardiography allows an adequate anatomical and functional definition of DMVO.

  13. Influence of Local Flow Field on Flow Accelerated Corrosion Downstream from an Orifice

    Utanohara, Yoichi; Nagaya, Yukinori; Nakamura, Akira; Murase, Michio

    Flow accelerated corrosion (FAC) rate downstream from an orifice was measured in a high-temperature water test loop to evaluate the effects of flow field on FAC. Orifice flow was also measured using laser Doppler velocimetry (LDV) and simulated by steady RANS simulation and large eddy simulation (LES). The LDV measurements indicated the flow structure did not depend on the flow velocity in the range of Re = 2.3×104 to 1.2×105. Flow fields predicted by RANS and LES agreed well with LDV data. Measured FAC rate was higher downstream than upstream from the orifice and the maximum appeared at 2D (D: pipe diameter) downstream. The shape of the profile of the root mean square (RMS) wall shear stress predicted by LES had relatively good agreement with the shape of the profile of FAC rate. This result indicates that the effects of flow field on FAC can be evaluated using the calculated wall shear stress.

  14. Effect of Flow Rate of Side-Type Orifice Intake on Withdrawn Water Temperature

    Xueping Gao


    Full Text Available Side-type orifice intake is a type of selective withdrawal facility used in managing reservoirs to mitigate the negative effects of low-temperature water. Based on the temperature data of a thermal stratified reservoir in China, an experiment was conducted in flume to study the influence of intake flow rate on withdrawn water temperature with different temperature distributions. Results indicated that withdrawn water temperature changed with different flow rates. The temperature change was determined by the water temperature gradients above and below the intake, whereas the change trend of temperature depended on the difference between the water temperature gradient above and below the intake. We likewise proposed a new equation with which the withdrawn water temperature of a thermal stratified reservoir using a side-type orifice could be calculated. These findings could be directly applied to the design and operation of side-type orifice intake in thermal stratified reservoirs.

  15. Effect of flow rate of side-type orifice intake on withdrawn water temperature.

    Gao, Xueping; Li, Guangning; Han, Yunpeng


    Side-type orifice intake is a type of selective withdrawal facility used in managing reservoirs to mitigate the negative effects of low-temperature water. Based on the temperature data of a thermal stratified reservoir in China, an experiment was conducted in flume to study the influence of intake flow rate on withdrawn water temperature with different temperature distributions. Results indicated that withdrawn water temperature changed with different flow rates. The temperature change was determined by the water temperature gradients above and below the intake, whereas the change trend of temperature depended on the difference between the water temperature gradient above and below the intake. We likewise proposed a new equation with which the withdrawn water temperature of a thermal stratified reservoir using a side-type orifice could be calculated. These findings could be directly applied to the design and operation of side-type orifice intake in thermal stratified reservoirs.

  16. An intercomparison of NEL and DHL water flow facilities using a twin orifice plate flowmeter assembly

    Dejong, J.; Spencer, E. A.


    A 205 mm transfer standard orifice plate meter assembly, consisting of two orifice plates in series separated by a length of pipe containing a flow straightener, was calibrated in two water flow facilities. Results show that the agreement in the characteristics of such a differential pressure transfer standard package is within 0.17% over a 10:1 range from flow rates of approximately 8 to 80 l/sec. When the range over which the comparison was made was limited to that for which the calibration graphs gave straight lines, the agreement is 0.1% in 3 of the 4 calibrations (0.17% in the fourth).

  17. Developing Modularized Virtual Reality Simulators for Natural Orifice Translumenal Endoscopic Surgery (NOTES).

    Ahn, Woojin; Dorozhkin, Denis; Schwaitzberg, Steven; Jones, Daniel B; De, Suvranu


    Natural orifice translumenal endoscopic surgery (NOTES) procedures are rapidly being developed in diverse surgical fields. We are developing a Virtual Translumenal Endoscopic Surgery Trainer (VTEST™) built on a modularized platform that facilitates rapid development of virtual reality (VR) NOTES simulators. Both the hardware interface and software components consist of independent reusable and customizable modules. The developed modules are integrated to build a VR-NOTES simulator for training in the hybrid transvaginal NOTES cholecystectomy. The simulator was demonstrated and evaluated by expert NOTES surgeons at the 2015 Natural Orifice Surgery Consortium for Assessment and Research (NOSCAR) summit.

  18. Suppress Method for Armature Melting Based on Muzzle Shunt%基于炮口分流的电枢熔化抑制方法

    王志恒; 万敏; 李小将; 黄勇


    For effectively solving the problem of the armature melting, this paper proposed suppress method of armature melting based on muzzle shunt for reducing contact resistance Joule heat. The mechanism of armature melting is analyzed, design three reducing contact resistance Joule heat schemes:resistor muzzle shunt, inductance muzzle shunt, and capacitor muzzle shunt. The heat power and output of 3 schemes are simulated and calculated, and analyzed suppress effect of 3 schemes on armature melting. The results show that the resistor muzzle shunt scheme and inductance muzzle shunt scheme can significantly reduce the contact resistance of Joule heat, thereby suppressing the armature melting, while, these two schemes have to increase the input current to compensate the effect of muzzle shunt on armature electromagnetic force. The effect of capacity muzzle shunt scheme is very limited. Thus, the capacity muzzle shunt scheme cannot suppress armature melting.%为有效解决轨道炮电枢熔化问题,提出一种基于炮口分流降低接触电阻焦耳热功率的电枢熔化抑制方法。分析了电枢熔化形成机理,设计了电阻器、电感器和电容器炮口分流3种降低接触电阻焦耳热方案,仿真计算了3种炮口分流方案接触电阻焦耳热功率和产生量,分析了3种方案对电枢熔化的抑制效果。结果表明:电阻器和电感器炮口分流方案可使接触电阻焦耳热产生量显著降低,能够抑制电枢熔化,但是需要增加输入电流补偿炮口分流对电枢电磁力的影响;电容器炮口分流效果十分有限,起不到抑制电枢熔化的作用。

  19. 高速电枢的尾翼结构设计及实验研究%Design and experiment of tail structure of armature with high velocity

    李敏堂; 潘如政; 王凤忠; 严萍; 袁伟群; 陈允; 徐伟东


    设计了T2LXD1系列电枢,分析了6061-T6铝合金材料的弹塑性特点,利用线性强化理论和接触理论并结合ANSYS软件,建立了T2LXD1系列电枢弹塑性接触模型,研究了电枢尾翼结构对电枢/导轨滑动界面接触状态的影响规律,得到了界面接触力、接触面积和接触压力分布等状态参数的数值模拟结果.利用短导轨电磁驱动系统,进行了T2LXD1系列电枢滑行实验,分析了电枢/导轨界面滑磨状态,比较了滑行性能曲线.实验结果表明:长尾翼电枢并不能带来实际接触面积的增加,电枢的滑行性能随着电枢尾翼长度的增加反而减小;对于柔顺性好的电枢和短导轨来说,适当增加滑动界面的预紧接触力能够提高电枢的滑行性能.%The T2LXD1 series armatures are designed and the elastic-plastic characteristics of 6061-T6 aluminum alloy is analyzed. The linear hardening theory, the contact theory, and the ANSYS software are utilized to build the elastic-plastic contact model of the T2LXD1 series armatures. The effect of tail structure on the contact condition of the armature-rail interface is studied, and the interfacial contact parameters such as contact force, contact area and contact pressure are simulated and obtained. A small electromagnetic drive system with short rail is used to execute the sliding experiments of T2LXD1 series armatures, and the interfacial wearing conditions are analyzed, the sliding performance curves are compared. The experimental results show that the long tail can not increase the effective contact area, and longer tail results in lower sliding performance of armature; for the flexible armature and the short rail, to properly increase the pretightening contact force of the interface can improve the sliding performance of armature.

  20. Requirements for Vertically Installed Runoff Control Boards for the “Paddy Field Dam” and Appropriate Orifice Shapes

    Natsuki, Yoshikawa; Hideyuki, Koide; Shin-Ichi, Misawa

    While the “Paddy Field Dam” project has been recognized as an effective flood control measure, there are some cases in which the runoff control boards are vertically installed on the opening of the drainage boxes without careful consideration of the orifice shape and size. The important criteria for the runoff control boards to be satisfied are: 1. to maintain a sufficient peak runoff control function, 2. to avoid excessive ponding causing overflow, 3. to minimize the influence to the ordinary water management, and 4. to reserve sufficient orifice area to avoid blockage of the orifice with floating litters. The purpose of this study is to examine proper shapes and sizes of the orifice to satisfy the criteria for the vertically installed runoff control boards through experiments and simulations. Given the condition that the orifice has sufficient area to avoid overflow with 10 and 20 year return period rainfall event (criteria 2), the simulation results show that the orifice with horizontally wider shapes has advantages over the square or circular shapes in terms of the criteria 1 and 3. The disadvantage of the horizontally wider shapes is the blockage of the orifice with floating litters (criteria 4). In conclusion, we proposed to secure sufficient vertical distance to avoid this problem by setting a lower limit on the vertical distance and then determine the widest horizontal distance to optimize all the criteria. In addition, we have constructed the “Orifice Design Assist Tool” on the basis of the examinations in this study.

  1. 绕制电枢和实体电枢动态特性对比研究%Research on comparison of dynamic characteristics of wound with solid armatures

    李三群; 关晓存; 李治源; 刘书蒙


    基于电磁场理论和麦克斯韦方程组,推导了含有实体电枢和绕制电枢涡流的磁场控制方程,并对此进行有限元求解;利用电磁场仿真软件ANSOFT Maxwell对实体电枢和绕制电枢的轴向电磁力、速度和电流分布进行了仿真,并对此进行对比分析,得出绕制电枢的电磁特性优于实体电枢,为下一步绕制电枢的制造和加工打下基础.%Based on Maxwell equation and electromagnetic field theory, magnetic field control equations with eddy current of solid armature and wound armature are presented in this paper. The equations are solved by finite ele ment method. Based on finite element software ANSOFT Maxwell, the simulative research on axial electromagnetic force, speed and eddy current distribution of solid armature and wound armature are made in ANSOFT. Through comparison of them, it is concluded that the electromagnetic characteristics of wound armature are better than solid armature, which forms the foundation for wound armature fabrication and handling.



    The instantaneous flow characteristics of circular orifice synthetic jet was experimentally studied by a phase-locked Particle Image Velocimetry (PIV) system. The instantaneous flowfields, including the forming, developing and breaking down of the vortex for the jet were clearly shown by the PIV experimental results. As the basis of the study of the instantaneous flow, 36 images were taken and phase-averaged for each condition. The PIV experiment was mainly focused on the time evolution of the vortex pairs formed in the push cycle, the saddle point existing in the suck cycle, the variation of the centerline velocity in the whole cycle and the cross-stream velocity profiles and their self-similarity. Finally, the orifice depth was changed from 1.5 mm to 2 mm and 3.5 mm in order to study the effect of different orifice depths on the flow structure, which shows that at all stream wise sections, the peak of the mass flux and momentum flux increases as the orifice depth increases. Furthermore, the nondimensional distance of the mass flux from the exit is the maximum, while the nondimensional distance of the centerline velocity peak from the exit is the minimum, and nondimensional distance of the momentum flux from the exit section is between them.


    Gao Hong; Lin Wanlai; Fu Xin; Yang Huayong; Tsukiji Tetsuhiro


    The aim of this study is to suppress a cavitation near the orifice of a relief valve by changing the shape of a poppet. An experimental flow visualization technique and a numerical cavitating flow simulation, using a RNG k-ε turbulence model and a cavitation model, are employed to achieve the purpose. In the flow visualization, the cavitation phenomenon near the orifice of a relief valve is observed using a transparent test valve body model and a camera. On the other hand, a three dimensional cavitating flow simulation is conducted to predict the cavitation near the orifice of a relief valve.Six types of poppets are designed by changing the shape of a traditional poppet shape, which is expected to influence the cavitating flow in an orifice. In addition, the cavitation noise of a relief valve is measured and the noise spectrum is analyzed. In conclusion, the cavitation intensity and the cavitation noise are reduced for an optimal poppet geometry obtained in the present study.

  4. Fatigue Properties and Fracture Mechanism of Aluminum Alloy with Orifice Chamfer and Pre-corrosion Damage

    ZHOU Song


    Full Text Available Fatigue fracture often occurs because of the corrosion damage to aerospace structural aluminum alloy with holes. Fatigue tests of 7075 aluminum alloy of both unchamfered and chamfered double-hole specimens under uncorrosion and 24h pre-corrosion were carried out. The influence of both pre-corrosion damage and orifice chamferer on fatigue properties and the differences of fatigue fracture characteristics were analyzed. The results show that the effect on fatigue life of pre-corrosion damage is significant. Median fatigue lives of both unchamfered and chamfered double-hole specimens under 24h pre-corrosion decrease about 31.74% and 26.92% compared with uncorrosion specimens. The orifice chamferer have a certain effect on fatigue life of both uncorrosion and 24h pre-corrosion specimens, with median fatigue lives decreased about 28.02% and 15.36% compared with unchamfered specimens, the main reason is due to the stress concentration after orifice chamfered, on the other hand, cutting marks lead to pre-damage during the orifice chamfering process which will result in an increase of the fatigue crack initiation sites and the fracture probability.


    田振国; 杨阳; 白象忠


    通过计算电枢移动过程中电枢附近的磁场分布以及通过电枢的电流密度分布,可以得到电枢上各点的洛仑兹力,积分后可得整个电枢受到的推力.同时考虑电流通过电枢时的电磁热效应产生的膨胀量及导轨与电枢间的摩擦,可以得到电枢在导轨内运动过程中的受力、速度变化.在此基础上利用Ansys软件建立发射状态时的三维计算模型,结合之前理论分析来定义边界条件、接触条件以及电枢推力曲线.通过具体算例,分析导轨与电枢间接触应力分布随电枢移动的变化,讨论相关物理量与材料性质、接触条件等的关系,从而为电磁轨道发射装置的强度设计提供依据.%Through calculating the magnetic field near the armature and the current density distribution in armature during the armature movement, the Lorentz force at every point of the armature can be obtained. Therefore, the thrust acted on the armature is got by integral. At the same time, considering the net expansion due to the electromagnetic heat effect of the armature when current discharging from the armature, and the friction between the rail and the armature, the force and the speed of the armature can be obtained when the armature moves in the guide rail. Based on the known results, the three-dimensional computational model is built using the Ansys software, and the boundary condition, contact condition, curve of thrust are be defined, it is analysed that analyses the change of contact stresses between armature and rail during armature move, and discussed the relation between these physical quantities regarding material properties and the contact condition by using a numerical example.

  6. 衔铁的成形工艺及模具设计%Forming Technology and Die Design for Armature



    The forming technology of armature was analysed from the standpoint of characteristics of part and materials,deformation for load-carrying capability and the selection of the forming equip-ment. The structure of the die,JavaBean and its working process were introduced. The experience and reference were provided in die design of similar parts.%从制件特点、材料性能、受力变形和成形设备选用角度,分析了衔铁的成形工艺,介绍了模具结构、设计注意事项及模具工作过程,为同类型零件的模具设计提供了经验及借鉴。

  7. 电机转子失效模式分析%On the Motor Armature Failure Mode Analysis

    李军毓; 蒲瑜


    In the test and use of power tools, it’s very common to see the motor armature failure phenomenon of commutator shorted, winding burned, electrical corrosion, shaft broken when the electromechanical energy transforms. This article analyses the causes of various failure phenomenon, preventing and reducing the incidence of potential failure.%在电动工具的测试和使用中,机电能量转换时换向器短路、线圈烧毁、电气腐蚀、轴断裂等电机转子失效现象较为常见。分析各类失效现象的产生原因,避免和减少潜在失效的发生。

  8. On the propagation mechanism of a detonation wave in a round tube with orifice plates

    Ciccarelli, G.; Cross, M.


    This study deals with the investigation of the detonation propagation mechanism in a circular tube with orifice plates. Experiments were performed with hydrogen air in a 10-cm-inner-diameter tube with the second half of the tube filled with equally spaced orifice plates. A self-sustained Chapman-Jouguet (CJ) detonation wave was initiated in the smooth first half of the tube and transmitted into the orifice-plate-laden second half of the tube. The details of the propagation were obtained using the soot-foil technique. Two types of foils were used between obstacles, a wall-foil placed on the tube wall, and a flat-foil (sooted on both sides) placed horizontally across the diameter of the tube. When placed after the first orifice plate, the flat foil shows symmetric detonation wave diffraction and failure, while the wall foil shows re-initiation via multiple local hot spots created when the decoupled shock wave interacts with the tube wall. At the end of the tube, where the detonation propagated at an average velocity much lower than the theoretical CJ value, the detonation propagation is much more asymmetric with only a few hot spots on the tube wall leading to local detonation initiation. Consecutive foils also show that the detonation structure changes after each obstacle interaction. For a mixture near the detonation propagation limit, detonation re-initiation occurs at a single wall hot spot producing a patch of small detonation cells. The local overdriven detonation wave is short lived, but is sufficient to keep the global explosion front propagating. Results associated with the effect of orifice plate blockage and spacing on the detonation propagation mechanism are also presented.

  9. How the anal gland orifice could be found in anal abscess operations

    Shahram Paydar


    Full Text Available Background: On an average 30-50% of patients who undergo incision and drainage (I and D of anal abscess will develop recurrence or fistula formation. It is claimed that finding the internal orifice of anal abscess to distract the corresponding anal gland duct; will decline the rate of future anal fistula. Surgeons supporting I and D alone claim that finding the internal opening is hazardous. This study is conducted to assess short-term results of optional method to manage patients with anal abscess and fitula-in-ano at the same time. Materials and Methods: In this cross-sectional descriptive study 49 from 77 patients with anal abscess whose internal orifice was not identified by pressing on the abscess, diluted hydrogen peroxide (2% and methylene blue was injected into the abscess cavity and the anal canal was inspected to find out the internal opening. Once the opening was distinguished, an incision was given from the anal verge to the internal opening. Results: The internal orifice was identified in 44 out of 49 patients (90% who underwent this new technique. Up to 18 months during follow-up, only 2.5% of patients with primary fistulotomy developed fistula on the site of a previous abscess. Conclusion: Conventional method to seek the internal orifice of anal abscesses is successful in about one-third of cases. By applying this new technique, surgeons would properly find the internal opening in >90% of patients. Needless to say, safe identification of the anal gland orifice in anal abscess disease best helps surgeons to do primary fistulotomy and in turn it would significantly decrease the rate of recurrence in anal abscess and fistula formation.

  10. Nouvelles Techniques d'Intervention sur la Corrosion des Armatures du Béton Armé

    Colloca, C


    Les principaux dégâts constatés dans les armatures passives du béton armé sont la corrosion généralisée et la corrosion locale. Ces dégradations sont provoquées soit par la carbonatation du béton soit par le contact avec l'eau pure ou l'eau chargée de chlorures pénétrant dans les pores et dans les fissures de surface. Ce document présente de nouvelles techniques d'intervention, fondées sur d'anciens principes, introduites pour le traitement électrochimique des zones altérées liées aux différentes conditions. La réalcalinisation (dans le cas de béton carbonaté) permet d'augmenter le pH du béton et de rétablir un niveau de basicité garantissant la passivation de l'armature. La désalification (dans le cas de béton entamé par les chlorures) provoque l'élimination des ions chlorure à travers la surface du béton. Les avantages de ces traitements, par rapport aux anciennes techniques, sont appréciables si l'on considère la durée d'exécution et leur coût moins élevé.

  11. 线圈炮电枢电磁—热耦合仿真分析%Simulation analysis of electromagnetic-thermal coupling for armature in inductive coilgun

    关晓存; 李治源; 赵然; 程二威


    According to Maxwell's equations and heat-conduction differential equation, a mathematical model is developed to describe the distribution of electromagnetic field, inductive eddy current and thermal field for multi-stage induction coilgun. Based on the finite element method(FEM) analysis of electromagnetic and thermal fields, a three-dimensional FEM model is built. When ignoring the inter-stage effect, armature temperature rise calculated in multi-stage is equivalent to multiple armature temperature rise calculated in single-stage, the practical induction heating quenching process is simulated by using ANSYS software. The rela tionship between the physical parameters of the coilgun and the resulting temperature is considered during the computation. The simulated results indicate that: 1. Temperature rise inside of the armature is concentrated in the exterior surface and the tail of the armature. 2. Temperature of the armature rises when voltage and capacity increases, because of increasing eddy current. 3. Trigger position and speed match relation of the armature influence temperature of the armature greatly. 4. Temperature of the armature in creases by increasing stage numbers of coilgun before the armature is melted. The results provide reference for the multi-stage coilgun project and its application.%从麦克斯韦方程组和导热微分方程出发,导出了3维多级感应线圈炮电磁场、温度场分布的基本方程,并以电磁场和温度场有限元分析为基础,建立了3维有限元分析模型,忽略级间的相互影响,多级线圈炮中电枢温升可以等效为多个单级电枢的温升,运用通用有限元分析软件ANSYS的耦合计算流程,对单级感应线圈炮中电枢电磁场和温度场进行仿真.计算中考虑了材料物理参数随温度变化对温度场的影响.仿真结果表明:电枢内的温升主要分布在电枢的外表面和尾部;电枢的温度随着电容器组电压和电容增加而升高,这是因

  12. Influence of orifice-to-wall distance on synthetic jet vortex ring simpinging on a fixed wall

    XU; Yang; FENG; LiHao


    Two-dimensional particle image velocimetry (PIV) is used to investigate the influence of the orifice-to-wall distance on synthetic jet vortex rings impinging on a fixed wall. Both evolutions of vortical structures and statistical characteristics of flow fields at different orifice-to-wall distances are presented. It is found that different orifice-to-wall distances have different effects in terms of the vortex strength and impinging speed when the vortex rings are approaching the wall. The secondary vortex ring can be observed within the shear layer only when the dimensionless orifice-to-wall distance is close to or less than the dimensionless stroke length. Consequently, an appropriate orifice-to-wall distance plays a vital role in the sense of impingement effect. The statistical analysis of the flow field indicates that a wall jet forms after impingement, while both the decay rate of the maximum radial velocity and the spreading rate of the half-width decrease with the increasing orifice-to-wall distance. The non-dimensional wall jet velocity profiles at different orifice-to-wall distances all exhibit self-similar behaviors, which is consistent with the theoretical solution of the laminar wall jet.

  13. High Viscosity Liquid Flow through the Round Orifices at Small Reynold’s Numbe rs

    V. N. Pil'gunov


    Full Text Available The paper presents research results of the mineral oil flow process with viscosity of 30 cSt through a round orifice with the sharp inlet edge of 0.9 mm in diameter. Pilot studies were conducted using a module from the transparent plexiglas that allowed to visualize hydrodynamic processes. The intake and off-take channels of the module with their sufficient extension had diameter of 20 mm (24 diameters of an orifice that allows us to consider compression of a stream as perfect. Drawing the enameled nichrome wire with a mark as a stripping isolation of 0.1 mm width enabled sounding of electric processes in the stream sections. Intensive high- frequency electric processes were revealed in cavitation stream. The paper gives experimental values of coefficientsof volumetric and mass flow at low (150 orifice. Free jet at a speed exceeding 50 m/s strikes a wall, barrier, installed at a distance of 100 diameters of the orifice: the reflection from walls, barriers shot blast, which caused intense foaming and conversion of oil into the two-phase mixture "fluid- combined air." We investigate the "life cycle" of a two-phase mixture: flotation bubbles in a viscous medium, and there was no air passes completely evolved in the dissolved state in a time not exceeding 30 minutes. Volumetric analysis of the foam allowed us to estimate the percentage of volumetric gas content of oil, which was 9% at 240С and atmospheric pressure of 97.5 kPa. An explanation of the possible cause cavitation edge at the end of a viscous fluid through an orifice with a sharp edge - appearance in fluid large tensile forces due to the centrifugal force on the particles of the fluid streams in passing peripheral sharp edge. Experimental research data flow of a viscous fluid in the annular orifice formed sharp edge and the surface of the string. Detected failure mode expiration free jet and conversion shareware transparent

  14. Organic compounds generated after the flow of water through micro-orifices: Were they synthesized?

    Tomiichi Hasegawa


    Full Text Available Micro-fluid mechanics is an important area of research in modern fluid mechanics because of its many potential industrial and biological applications. However, the field is not fully understood yet. In previous work, when passing ultrapure water (UPW in which air was dissolved (UPW* through micro-orifices, we found that the flow velocity decreased and stopped over time, and membranes were frequently formed in the orifice when the flow stopped. The membrane came from the dissolved air in UPW*, and membrane formation was closely related to electric charges generated in orifices by the flow. In the present paper, we clarified the components of the membrane and suggested a mechanism for membrane formation. We examined the effect of contaminants on the membrane formation and confirmed our previous results. We identified the chemical components of the membrane and those present in the UPW* itself by using an electron probe microanalyzer and found that the proportion of each element differed between the membrane and UPW*. Raman and infrared (IR spectroscopy showed that the membrane consisted of organic substances such as carotenoids, amides, esters, and sugars. We irradiated UPW* with ultraviolet light to cut organic chains that may be left in UPW* as contaminants. We found a similar membrane and organic compounds as in nonirradiated UPW*. Furthermore, although the UPW that was kept from contact with air after it was supplied from the UPW maker (UPW0 and bubbled with Ar gas (UPW0 bubbled with Ar formed no membrane, the UPW0 bubbled with CO2 formed thin membranes, and Raman and IR analysis showed that this membrane contained carboxylic acid salts, carotenoids, or a mixture of both. We found that electric grounding of the orifice reduces the probability of membrane formation and that the jets issuing from an aperture bear negative charges, and we assumed that the micro-orifices possess positive charges generated by flows. Consequently, we suggest that

  15. Flow and mass transfer downstream of an orifice under flow accelerated corrosion conditions

    Ahmed, Wael H., E-mail: [Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals (KFUPM), P.O. Box 874, Dhahran 31261 (Saudi Arabia); Bello, Mufatiu M.; El Nakla, Meamer; Al Sarkhi, Abdelsalam [Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals (KFUPM), P.O. Box 874, Dhahran 31261 (Saudi Arabia)


    Highlights: Black-Right-Pointing-Pointer Mass transfer downstream of orifices was numerically and experimentally investigated. Black-Right-Pointing-Pointer The surface wear pattern is measured and used to validate the present numerical results. Black-Right-Pointing-Pointer The maximum mass transfer coefficient found to occur at approximately 2-3 pipe diameters downstream of the orifice. Black-Right-Pointing-Pointer The FAC wear rates were correlated with the turbulence kinetic energy and wall mass transfer in terms of Sherwood number. Black-Right-Pointing-Pointer The current study offered very useful information for FAC engineers for better preparation of nuclear plant inspection scope. - Abstract: Local flow parameters play an important role in characterizing flow accelerated corrosion (FAC) downstream of sudden area change in power plant piping systems. Accurate prediction of the highest FAC wear rate locations enables the mitigation of sudden and catastrophic failures, and the improvement of the plant capacity factor. The objective of the present study is to evaluate the effect of the local flow and mass transfer parameters on flow accelerated corrosion downstream of an orifice. In the present study, orifice to pipe diameter ratios of 0.25, 0.5 and 0.74 were investigated numerically by solving the continuity and momentum equations at Reynolds number of Re = 20,000. Laboratory experiments, using test sections made of hydrocal (CaSO{sub 4}{center_dot} Vulgar-Fraction-One-Half H{sub 2}O) were carried out in order to determine the surface wear pattern and validate the present numerical results. The numerical results were compared to the plants data as well as to the present experiments. The maximum mass transfer coefficient found to occur at approximately 2-3 pipe diameters downstream of the orifice. This location was also found to correspond to the location of elevated turbulent kinetic energy generated within the flow separation vortices downstream of the orifice

  16. Analysis of Influencing Factors for the Dynamic Balance of Automotive Electronic Fuel Pump Armature%汽车电动燃油泵电枢动平衡的影响因素分析

    王继锁; 卜啸天; 楚鹏飞; 隽春玲


    简要介绍了汽车电动燃油泵电枢的结构,分析了汽车电动燃油泵电枢的主要零部件和电枢的主要生产过程及全自动动平衡机对燃油泵电枢动平衡的影响,为降低燃油泵电枢动不平衡量提供解决方向。%The framework of the automotive electronic fuel pump armature was introduced simply. The influences of the main parts of the fuel pump armature,the main manufacturing process of fuel armature and the full-automatic dynamic balance machine to the dynamic balance were analyzed. It provides solving direction to reduce the dynamic unbalance of fuel pump armature.

  17. Parametric measurements of the effect of in-duct orifice edge shape on its noise damping performance

    Ji, Chenzhen; Zhao, Dan; Han, Nuomin; Li, Jing


    Acoustic liners perforated with thousands of millimeter-size orifices are widely used in aero-engines and gas turbine engines as an effective noise damper. In this work, experimental investigations of the acoustic damping effect of in-duct perforated orifices are performed on a cold-flow pipe. A mean flow (also known as bias flow) is applied and its flow rate is variable. Emphasis is placed on the effect of the orifice edge shape. For this, 16 in-duct orifices with different edge shapes and porosities are designed and manufactured by using 3D printing technology and conventional laser cutting technique. The damping effect of these in-duct orifices is characterized by using power absorption coefficient Δ and reflection coefficient χ from 100 to 1000 Hz. The performances of these orifices are found to be either improved or deteriorated, depending on (1) edge shape, (2) the ratio T/d of orifice thickness to its diameter, (3) the bias flow Mach number, (4) downstream pipe length Ld and (5) porosity η via varying either the number N or surface area Ao of the orifices. In addition, modifying orifice edge does not lead to an increase of power absorption at lower frequency (⩽ 700 Hz). However, as the frequency is increased, the orifice with square (S-type) edge is found to be associated with 10 percent more power absorption. It is interesting to find that T/d over the tested range (≤ 0.5) has little influence on its damping capacity. However, the mean bias flow Mach number Ma and porosity η are shown to play critical roles on determining the noise damping performance of these orifices. Maximum power absorption Δmax is found to occur at Ma ≈ 0.018, while the optimum porosity corresponding to Δmax is approximately 7 percent. The present parametric measurements shed light on the roles of orifice edge shape, porosity and mean flow on its noise damping capacity, and facilitate the design of effective perforated liners.

  18. 同步感应电磁推进系统中电枢制造材料的选择%Analysis of Armature Material in Synchronous Inductive Electromagnetic Propulsion

    付磊; 蒋启龙; 朱英伟; 董亮; 王豫


    Some theoretical analysis of the synchronous inductive electromagnetic propulsion was carried out and the equivalent circuit model of single-stage system was established, thus setting up a relation with the eddy current and the armature material parameters. Based on the electromagnetic field finite element software, the influence of armature material parameters on armature stress, armature speed and energy operating fator was analyzed. Simulation results reveal that the armature material parameters influence the armature stress, the operating factor and the mass of the projectile directly and the aluminous is the best choice for making armature. This result is useful for the design of armature.%对同步感应电磁推进系统进行了理论分析并建立了单级系统的电路模型,直接建立了电枢制造材料的基本物理参数与电枢感应涡流之间的联系.通过有限元仿真软件模拟比较了不同材质的电枢对电枢受力及电枢加速速度的影响,计算了不同材质电枢对整体系统能量转化效率的影响.结果表明:电枢制造材料的选择将影响电枢的受力方式、整体系统的能量转化率及有效加速载荷的质量,铝制材料在几种电枢制造材料中表现最优.以上分析可为同步感应型电磁推进系统的电枢设计提供参考.

  19. Simulation of helical coil electromagnetic launcher' s radial force and design of armature%螺旋线圈电磁发射器径向受力仿真与电枢设计

    杨栋; 沈志; 刘振祥; 杨丽佳; 蒋雅琴; 欧阳建明


    The radial magnetic field distribution of the helical coil electromagnetic launcher' s driving coil is investigated by numerical simulation, from which a “D” shaped cross section armature is proposed and its best location is determined. The results show that, with the same size, the acceleration of the “D” shaped armature is bigger than the rectangular armature, i.e. , with the same length of the launcher, the muzzle velocity of the “D” shaped armature is bigger than the rectangular armature. Taking the “D” shaped armature as an example, the axial and radial force distribution of the armature coil and the driving coil is investigated. The results show that the radial forces on the armature coil and the driving coil are mainly swelling forces, and the structure surround the coils should be reinforced in the launcher design.%通过数值仿真,根据螺旋线圈电磁发射器(HCEL)驱动线圈的径向磁场分布,提出一种"D"形截面电枢并确定其最佳受力位置.计算表明,相同线度的"D"形电枢比矩形电枢加速度更大,即在炮长(弹丸加速长度)相同的情况下,"D"形电枢比矩形电枢具有更高的出口速度.以"D"形电枢为例,分析了弹丸线圈与驱动线圈上的轴向、径向受力分布.结果表明,弹丸线圈与驱动线圈的径向力主要为向外的膨胀力,在炮结构的工程设计中应在线圈外围进行加固.

  20. Analysis on Initial Velocity of Armature of Electromagnetic Rail Launching Experiment Based on Grey Model%基于灰色模型的电磁轨道发射实验电枢初速分析

    张祎; 杨春霞; 杨栋; 栗保明


    To research the influencing factors of the armature muzzle velocity and the identification method for armature transition of electromagnetic rail launching systems, nonlinear GM ( 1, N ) grey models of interior ballistic theoretical calculation and experimental data are established based on the analysis of grey relations entropy. The coordination of influencing factors is quantitatively analysed through the comparison of the values and polarity of driving coefficients. The results show that; in e-lectromagnetic rail launching experiments, the charge voltage promotes the armature muzzle velocity mostly, and the diameter of the armature takes second place; the position of the measuring velocity target inhibits the armature muzzle velocity mostly, and the mass of the solid armature takes second place;there is a certain inherent positive connection between the weight coefficient of the armature mass and armature transition.%为了研究电磁轨道发射系统电枢初速影响因素和电枢转捩的辨识方法,在灰关联熵分析的基础上,分别建立了外场试验数据和内弹道理论计算数据的非线性GM(1,N)灰色模型.通过对模型中驱动系数数值和极性的比较,对影响因素的动态协调性进行了定量分析.结果表明:在电磁轨道发射实验中,对电枢初速促进作用最大的是放电电压,其次是电枢直径;测速靶位置对电枢初速的抑制作用最大,电枢质量次之;电枢质量的权重与电枢转捩之间存在某种内在联系.

  1. Natural Orifice Transluminal Endoscopic Surgery (NOTES-an Emerging Technique in Surgery

    BM Shrestha


    Full Text Available Natural orifice transluminal endoscopic surgery (NOTES, which utilises natural anatomical passages for gaining access to the intra-abdominal organs for surgical interventions, that result in scarless surgery, is a recent advancement in the specialty of minimally invasive surgery and has gained significant momentum, It has been postulated as a promising alternative to laparoscopic surgery in the fi eld of minimal invasive surgery. Signifi cant advantages over conventional open surgery, such as less postoperative pain, a shorter hospital stay, early return to activity, avoidance of woundrelated complications and better cosmesis have been demonstrated. This article provides an update in the development, principles, practice and future applications of NOTES. Keywords: natural orifice, minimally invasive, scarless, endoscopic surgery.

  2. The numerical analysis about the flow-hunting characteristics of the orifice meter

    Shin, Chang Hoon; Ahn, Seung Hee; Chung, Jong Tae; Her, Jae Young; Kim, Woo Sik [Korea Gas Corporation, Sungnam (Korea, Republic of)


    Generally, the flow hunting is observed in almost all of the orifice meters but the intensity of the flow hunting is different at each metering system. So, we are getting the questions as follows; why such a difference occurs and whether it influence to metering error rate or not. To investigate the flow hunting characteristics, we are trying to examine the flow characteristics around the orifice meter when the transient flow or pressure is generated at after the PCV(Pressure Control Valve) by 3D CFD method. And we have compared numerical results with experimental results at M - PCV station in order to clarify the relations with both the metering-pipeline diameter and flow rate. Finally, we can show some major factors influencing to the flow hunting and propose some correcting scheme of the flow hunting equation.

  3. A sticky situation: management of spray polyurethane foam insulation in body orifices.

    Sowerby, Robert J; Sowerby, Leigh J; Vinden, Chris


    Spray polyurethane foam insulation is commonly used in the construction industry to fill gaps, seal, and insulate. We present three cases of intentional spray foam insertion in body orifices and discuss the management of such situations in the emergency department. This series includes a case of oral foam insertion used in a suicide attempt by suffocation and two cases of rectal insertion. All of these cases had potential long-term consequences; one was life-threatening. To our knowledge, this is the first published report on the medical management and removal of foam insulation from body orifices. In all three cases, the foam insulation material was successfully removed after allowing the material to harden.

  4. Optical measurements of gas bubbles in oil behind a cavitating micro-orifice flow

    Iben, Uwe; Wolf, Fabian; Freudigmann, Hans-Arndt; Fröhlich, Jochen; Heller, Winfried


    In hydraulic systems, it is common for air release to occur behind valves or throttles in the form of bubbles. These air bubbles can affect the behavior and the performance of these systems to a substantial extent. In the paper, gas release in a liquid flow behind an orifice is analyzed by optical methods for various operation points. The bubbles are observed with a digital camera, and a detection algorithm based on the Hough transformation is used to determine their number and size. The appearance of gas bubbles is very sensitive to the inlet and outlet pressure of the orifice. Gas bubbles are only observed if choking cavitation occurs. An empirical relationship between an adjusted cavitation number and the appearance of gas release is presented. It is assumed that the observed bubbles contain mostly air. With the applied pressure differences, up to 30 % of the dissolved air was degassed in the form of bubbles.

  5. Natural orifice total mesorectal excision using transanal port and laparoscopic assistance

    Tuech, Jean-Jacques; Bridoux, Valérie; Kianifard, Babak; Schwarz, Lilian; Tsilividis, Basile; Huet, Emmanuel; Michot, Francis


    Abstract Natural Orifice Transluminal Endoscopic Surgery (NOTES) is an emerging concept which has been recently applied to the field of rectal excision. The authors describe a case of total mesorectal excision using a transanal port and laparoscopic assistance We described a procedure performed in a A 45-year-old for a rectal adenocarcinoma (1cm wide, T1sm3) 3cm above the dentate line. The procedure is described in the text and in a didactic video. ...

  6. Emerging technologies including robotics and natural orifice transluminal endoscopic surgery (NOTES) colorectal surgery.

    Whiteford, Mark H; Swanstrom, Lee L


    Endoluminal and minimally invasive techniques have a long history and bright future in colorectal surgery. First, we will examine how old (colonoscopy) and new (laparoscopy) techniques combine in the form of laparoscopically assisted colonoscopic polypectomy for removal of "colonoscopically unresectable" colon polyps. Next, we will review the early experiences with robot-assisted minimally invasive colon resections. Lastly, we will introduce the next frontier in minimally invasive surgery, natural orifice transluminal endoscopic surgery (NOTES). 2007 Wiley-Liss, Inc

  7. Current developments in natural orifices transluminal endoscopic surgery:An evidence-based review

    Anthony; Yuen; Bun; Teoh; Philip; Wai; Yan; Chiu; Enders; Kwok; Wai; Ng


    Tremendous advances have been made in recent years addressing the key obstacles to safe performance and introduction of human natural orifice transluminal endoscopic surgery (NOTES). Animal studies have focused on identifying optimal solutions to these obstacles, in particular methods of creating transluminal access,safe closure of the point of access, and development of a multitasking platform with dedicated instruments. Whether the performance data generated from these animal studies can be reproduced in ...

  8. Technical skill set training in natural orifice transluminal endoscopic surgery: how should we approach it?

    Nugent, Emmeline


    The boundaries in minimally invasive techniques are continually being pushed further. Recent years have brought new and exciting changes with the advent of natural orifice transluminal endoscopic surgery. With the evolution of this field of surgery come challenges in the development of new instruments and the actual steps of the procedure. Included in these challenges is the idea of developing a proficiency-based curriculum for training.

  9. Effect of Flow Rate of Side-Type Orifice Intake on Withdrawn Water Temperature

    Xueping Gao; Guangning Li; Yunpeng Han


    Side-type orifice intake is a type of selective withdrawal facility used in managing reservoirs to mitigate the negative effects of low-temperature water. Based on the temperature data of a thermal stratified reservoir in China, an experiment was conducted in flume to study the influence of intake flow rate on withdrawn water temperature with different temperature distributions. Results indicated that withdrawn water temperature changed with different flow rates. The temperature change was de...

  10. Effects of Orifice Orientation and Gas-Liquid Flow Pattern on Initial Bubble Size

    刘长军; 梁斌; 唐盛伟; 闵恩泽


    In many gas-liquid processes, the initial bubble size is determined by a series of operation parameters along with the sparger design and gas-liquid flow pattern. Bubble formation models for variant gas-liquid flow pat-terns have been developed based on force balance. The effects of the orientation of gas-liquid flow, gas velocity, liquid velocity and orifice diameter on the initial bubble size have been clarified. In ambient air-water system, the suitable gas-liquid flow pattern is important to obtain smaller bubbles under the low velocity liquid cross-flow con-ditions with stainless steel spargers. Among the four types of gas-liquid flow patterns discussed, the horizontal orifice in a vertically upward liquid flow produces the smallest initial bubbles. However the orientation effects of gas and liquid flow are found to be insignificant when liquid velocity is higher than 3.2 m·s-1 or the orifice diameter is small enough.

  11. In vivo microrobots for natural orifice transluminal surgery. Current status and future perspectives.

    Forgione, A


    The possibility to operate inside the peritoneal cavity through small holes performed in hollow organs that is presented by Natural Orifice Transluminal Endoscopic Surgery (NOTES) represents a major paradigm shift in general surgery. While this new approach seems very appealing from patients' perspectives because it eliminates completely abdominal wall aggression and promises to reduce postoperative pain, it is very challenging for surgeons because of the major constraints imposed by both the mode of access and the limited technology currently available. For this reason NOTES applications at the present time are performed by only a few surgeons and mainly to perform non-complex procedures. While new devices are under development, many of them are trying mainly to simply improve current endoscopic platforms and seem not to offer breakthrough solutions. The numerous challenges introduced by natural orifice approaches require a radical shift in the conception of new technologies in order to make this emerging operative access safe and reproducible. The convergence of several enabling technologies in the field of miniaturization, communication and micro-mechatronics brings the possibility to realize on a large scale the revolutionary concept of miniature in vivo co-operative robots. These robots provide vision and task assistance without the constraints of the entry incision and have been shown in experimental settings to possess many qualities that could be ideal to partner with Natural Orifice Surgery. This article explores the current status of microrobotics as well as presents potential future scenarios of their applications in NOTES.

  12. Disinfection of the Access Orifice in NOTES: Evaluation of the Evidence Base

    Mikael H. Sodergren


    Full Text Available Introduction. Appropriate prevention of infection is a key area of research in natural orifice translumenal endoscopic surgery (NOTES, as identified by the Natural Orifice Surgery Consortium for Assessment and Research (NOSCAR. Methods. A review of the literature was conducted evaluating the evidence base for access orifice preparation/treatment in NOTES procedures in the context of infectious complications. Recommendations based on the Oxford Centre for Evidence-Based Medicine guidelines were made. Results. The most robust evidence includes several experimental randomised controlled trials assessing infectious complications in the transgastric approach to NOTES. Transvaginal procedures are long established for accessing the peritoneal cavity following disinfection with antiseptic. Only experimental case series for transcolonic and transvesical approaches are described. Conclusion. Grade C recommendation requiring no preoperative preparation can be made for the transgastric approach. Antiseptic irrigation is recommended for transvaginal (grade C NOTES access, as is current practice. Further human trials need to be conducted to corroborate the current evidence base for transgastric closure. It is important that future trials are conducted in a methodologically robust fashion, with emphasis on clinical outcomes and standardisation of enterotomy closure and postoperative therapy.

  13. Thermal analysis for the HTS stator consisting of HTS armature windings and an iron core for a 2.5 kW HTS generator

    Song, P.; Qu, T.-M.; Lai, L.-F.; Wu, M.-S.; Yu, X.-Y.; Han, Z.


    Most present demonstrations of high-temperature superconducting (HTS) synchronous motors/generators are partially superconducting, only installing HTS coils on the rotor as excitation windings. The possible applicability of HTS armature windings is an interesting research topic because these windings can certainly increase the power density attributed to a potentially high armature loading capacity. In this study, we analysed the thermal behaviours of a developed 2.5 kW-300 rpm synchronous generator prototype that consists of an HTS stator with Bi-2223-Ag armature windings on an iron core and a permanent magnet (PM) rotor. The entire HTS stator, including the iron core, is cooled with liquid nitrogen through conduction cooling. The rated frequency is set at 10 Hz to reduce AC loss. The properties of the HTS windings and the iron core are characterized, and the temperatures in the HTS stator under different operation conditions are measured. The estimated iron loss is 11.5 W under operation in 10 Hz at liquid nitrogen temperature. Conduction cooling through the silicon iron core is sufficient to cool the iron core and to compensate for the temperature increment caused by iron loss. The stable running capacity is limited to 1.6 kW when the armature current is 12.6 A (effective values) due to the increasing temperature in the slots as a result of the AC loss in the HTS coils. The thermal contact between the HTS coils and the cooling media should be improved in the future to take away the heat generated by AC loss.

  14. 电磁轨道炮电枢的运动特性研究%Research on Kinetic Characteristic of Armature of Electromagnetic Rail Gun

    靳智; 沈培辉; 刘凯


    In order to quickly and efficiently realize the anti-missile of electromagnetic rail gun, the air resistance and magnetic resistance of solid armature were studied. Based on the Maxwell’s theory, the mechanics properties of the armature in the gun tube are analyzed. By theoretical and simulation respectively to the armature resistance and electromagnetic air resistance are analyzed, the cross section and the influence of friction factors on the export of kinetic energy are compared, the optimal solution is got, and the measures of improving the armature launch are put forward. The results showed that low speed friction is greater than the air resistance, while the high speed period of air resistance has a greater impact to the mission.%为了快速有效地实现电磁轨道炮的反导,对其固体电枢电磁阻力与空气阻力角度等运动进行研究。在基于麦克斯韦理论的基础上,分析了电枢在炮管内的力学特性。通过理论仿真计算分别对电枢的电磁阻力及空气阻力进行了分析,比较了截面及摩擦因素对出口动能的影响,得到了最优方案,并提出了改进电枢发射的措施。研究结果表明:低速段摩擦力大于空气阻力,而高速段空气阻力对发射影响较大。

  15. The morphology of the cibarial armature and sensilla of Mansonia titillans, Psorophora cingulata, Coquillettidia arribalzagae, Culex coronator and Limatus durhamii (Diptera: Culicidae).

    Boza, Sandra; Vargas, Mario


    A detailed description of the cibarial armature of the Neotropical mosquitoes Mansonia titillans, Psorophora cingulata, Coquillettidia arribalzagae, Culex coronator and Limatus durhamii, is presented. A sample of 15 specimens of each species was taken from the collections of two mosquito ecological projects located at Santa Clara, San Carlos, Alajuela and from La Selva, Sarapiqui, Heredia, Costa Rica. Each specimen, preserved in alcohol, was cleared, put into a mounting medium, head separated from body and eyes pinched to expose the cibarial armature and sense organs; finally a coverslip was added for a permanent slide. The bodies of all the mosquitoes were also mounted onto slides. The descriptions of the cibarial armatures were based on the characteristics of the dome, body, transversal bar, lateral flanges and cibarial teeth. Also the number, distribution and type of the sense organs are given. From the analysis, and comparison with known descriptions of other neotropical species, we conclude that the five species studied show enough characteristics for species recognition purposes.

  16. 起动机电枢用半塑换向器焊接工艺研究%Starter Armature with Half a Commutator Welding Technology Research



    半塑换向器是起动电机电枢常用的主要零部件,电枢的焊接过程是电枢制作五大工艺中的其中之一。通过对半塑换向器的焊接工艺研究,分析半塑换向器的焊接特性,来制定最佳的焊接工艺方法,并总结出半塑换向器的焊接参数变化规律。%Plastic commutator is starting motor armature main components in common use. Welding process of the armature is the armature produced in the process of the five one of them. Through the model of the commutator welding technology research, analyzing and half plastic welding properties of commutator. To develop the best method of welding process, and sum up the half mold commutator welding parameter change rule.

  17. A simple expression for pressure drops of water and other low molecular liquids in the flow through micro-orifices

    Hasegawa, Tomiichi; Ushida, Akiomi; Narumi, Takatsune


    Flows are generally divided into two types: shear flows and shear-free elongational (extensional) flows. Both are necessary for a thorough understanding of the flow properties of a fluid. Shear flows are easy to achieve in practice, for example, through Poiseuille or Couette flows. Shear-free elongational flows are experimentally hard to achieve, resulting in an incomplete understanding of the flow properties of fluids in micro-devices. Nevertheless, flows through micro-orifices are useful for probing the properties of elongational flows at high elongational rates; although these flows exhibit shear and elongation, the elongation is dominant and the shear is negligible in the central region of the flows. We previously reported an anomalous reduction in pressure drops in the flows of water, a 50/50 mixture of glycerol and water, and silicone oils through micro-orifices. In the present paper, we rearrange the data presented in the previous paper and reveal a simple relationship where the pressure drop is proportional to the velocity through the micro-orifices, independent of the orifice diameter and the viscosity of the liquids tested. We explain our observations by introducing a "fluid element" model, in which fluid elements are formed on entering the orifice. The model is based on the idea that low molecular liquids, including water, generate strong elongational stress, similar to a polymer solution, in the flow through micro-orifices.

  18. 铝合金刷电枢的电磁发射特性研究%Investigations on Electromagnetic Launching Characteristic of Aluminum Alloy Brush Armature

    赵月红; 张丹丹; 赵晓玲; 战再吉


    电磁轨道发射过程中,电枢表面由于电流趋肤效应引起的电流集中会降低发射系统枢轨服役寿命.为抑制电流密度集中,实现电流分散,提出了一种新型铝合金刷电枢,并对其发射特性进行了研究.结果表明,在100~350 kA的发射试验中,刷电枢结构均保持完好.接触压力保持不变情况下,刷电枢的质量损失先随电流的增加而增大,到250 kA时达到峰值,随后呈逐渐减小的趋势.刷电枢质量损失与合金纤维直径有关,当其直径由0.1 mm提高到0.2 mm时,质量损失减小.选择合适的初始接触压力能够有效降低电枢质量损失,不同纤维直径的刷电枢对应不同的最佳初始压力.微观形貌观察结果表明,铝纤维损伤主要形式为机械磨损和电弧烧蚀.%During electromagnetic launching,the current often concentrates on the surface of the armature due to the speed skin effect,which may reduce the service life of a launch system.To inhibit the concentration of the current density,a new type of aluminum alloy brush armature was proposed and its launching properties were studied.Results show that the main structure of the brush armature was intact within the scope of the experimental conditions.The contact pressure being kept constant,the mass loss of the brush armature at first increased with the increase of the current from 200 to 250 kA,then decreased with the further increase of the current from 250 to 350 kA.The mass loss of the brush armature decreased with the increase of the fiber diameter from 0.1 to 0.2 mm.An appropriate initial contact pressure could effectively reduce the mass loss of the armature.The brush armature with a different fiber diameter corresponded to a different optimal initial pressure.The microstructural observation results show that the main forms of damage of the aluminum fiber were mechanical wear and arc ablation.

  19. The Performance Test for Reactor Coolant Pump (RCP) adopting Variable Restriction Orifice Type Control Valve

    Kim, S.; Bae, B. U.; Cho, Y. J. and others


    The design values of the RCPTF are 17.2 MPa, 343 .deg. C, 11.7 m{sup 3}/s, and 13 MW in the maximum pressure, temperature, flow rate, and electrical power, respectively. In the RCPTF, various types of tests can be performed including a hydraulic performance test to acquire a H-Q curve as well seal transient tests, thrust bearing transient test, cost down test, NPSHR verification test, and so on. After a commissioning startup test was successfully perfomed, mechanical structures are improved including a flow stabilizer and variable restriction orifice. Two- branch pipe (Y-branch) was installed to regulate the flow rate in the range of performance tests. In the main pipe, a flow restrictor (RO: Restriction Orifice) for limiting the maximum flow rate was installed. In the branch pipe line, a globe valve and a butterfly valves for regulating the flow rate was located on the each branch line. When the pressure loss of the valve side is smaller than that of the RO side, the flow rate of valve side was increasing and the flow disturbance was occurred in the lower pipe line. Due to flow disturbnace, it is to cause an error when measuring RCP head and flow measurement of the venturi flow meter installed in the lower main pipe line, and thus leading to a decrease in measurement accuracy as a result. To increase the efficiency of the flow control availability of the test facility, the variable restriction orifice (VRO) type flow control valve was designed and manufactured. In the RCPTF in KAERI, the performance tests and various kinds of transient tests of the RCP were successfully performed. In this study, H-Q curve of the pump using the VRO revealed a similar trend to the result from two ROs. The VRO was confirmed to effectively cover the full test range of the flow rate.

  20. Creating Small Gas Bubbles in Flowing Mercury Using Turbulence at an Orifice

    Wendel, Mark W [ORNL; Abdou, Ashraf A [ORNL; Paquit, Vincent C [ORNL; Felde, David K [ORNL; Riemer, Bernie [ORNL


    Pressure waves created in liquid mercury pulsed spallation targets have been shown to create cavitation damage to the target container. One way to mitigate such damage would be to absorb the pressure pulse energy into a dispersed population of small bubbles, however, creating such a population in mercury is difficult due to the high surface tension and particularly the non-wetting behavior of mercury on gas-injection hardware. If the larger injected gas bubbles can be broken down into small bubbles after they are introduced to the flow, then the material interface problem is avoided. Research at the Oak Ridge National Labarotory is underway to develop a technique that has shown potential to provide an adequate population of small-enough bubbles to a flowing spallation target. This technique involves gas injection at an orifice of a geometry that is optimized to the turbulence intensity and pressure distribution of the flow, while avoiding coalescence of gas at injection sites. The most successful geometry thus far can be described as a square-toothed orifice having a 2.5 bar pressure drop in the nominal flow of 12 L/s for one of the target inlet legs. High-speed video and high-resolution photography have been used to quantify the bubble population on the surface of the mercury downstream of the gas injection sight. Also, computational fluid dynamics has been used to optimize the dimensions of the toothed orifice based on a RANS computed mean flow including turbulent energies such that the turbulent dissipation and pressure field are best suited for turbulent break-up of the gas bubbles.



    This paper reports results of research on the stability of a hydraulic servo position system using generalization pulse code modulation (GPCM) and common on/off valves for hydraulic servo control. The de- scribing function was first used to analyze the system′s stability, and based on the nonlinear theory, an equation calculating the minimum orifice area of GPCM valves was derived by applying results of analysis on the stability of the GPCM control system. In the end, aimed at developing a hydraulic servo position system to be used in a paint robot, simulation and experiment were carried out. The results show that the theoretical conclusions accorded with practical results.

  2. Double-Orifice Mitral Valve in an Eight-Year-Old Boy.

    Segreto, Antonio; De Salvatore, Sergio; Chiusaroli, Alessandro; Bizzarri, Federico; Van Wyk, Cornelius; Congiu, Stefano


    The case is described of an eight-year-old boy who required an operation for moderate mitral regurgitation due to a double-orifice mitral valve (DOMV). The DOMV, which was clearly demonstrated by transthoracic echocardiography, had a central fibrous bridge. Mitral valve repair using a 5/0 Prolene suture placed at the level of the superior commissure of each hole to stabilize the valve, and ring annuloplasty with Edwards Physio ring, was successfully performed. Intraoperative real-time transesophageal echocardiography showed the repaired DOMV to be without regurgitation or stenosis.

  3. Method and apparatus for fine tuning an orifice pulse tube refrigerator

    Swift, Gregory W.; Wollan, John J.


    An orifice pulse tube refrigerator uses flow resistance, compliance, and inertance components connected to a pulse tube for establishing a phase relationship between oscillating pressure and oscillating velocity in the pulse tube. A temperature regulating system heats or cools a working gas in at least one of the flow resistance and inertance components. A temperature control system is connected to the temperature regulating system for controlling the temperature of the working gas in the at least one of the flow resistance and inertance components and maintains a control temperature that is indicative of a desired temporal phase relationship.

  4. How the anal gland orifice could be found in anal abscess operations

    Shahram Paydar; Ahmad Izadpanah; Leila Ghahramani; Seyed Vahid Hosseini; Alimohammad Bananzadeh; Salar Rahimikazerooni; Faranak Bahrami


    Background: On an average 30-50% of patients who undergo incision and drainage (I and D) of anal abscess will develop recurrence or fistula formation. It is claimed that finding the internal orifice of anal abscess to distract the corresponding anal gland duct; will decline the rate of future anal fistula. Surgeons supporting I and D alone claim that finding the internal opening is hazardous. This study is conducted to assess short-term results of optional method to manage patients with anal ...

  5. Experimental investigation of key parameters pertinent to multi-hole orifice throttling characteristic

    ZHAO Tian-yi; ZHANG Ji-li


    This study firstly defines a set of arrangement rule for perforated holes of multi-hole orifice (MO), and then presents three critical geometrical parameters including total number of performated hole, equivalent diameter ratio and distribution density of perforated holes, which are to quantify MO structure. This paper built the throttling test apparatus for nice test MO plates, which were designed according to orthogonal theory. The experiments were conducted to investigate the effect of three critical geometerical parameters on the pressure loss coefficient of test MOs. Results show that equivalent diameter ratio is the dominant prameter affecting MO throttling characterstic.

  6. Redoing a bioprosthetic tricuspid valve replacement with pacemaker wire through the ruined bioprosthetic valve orifice

    GUO Hong-wei; PAN Shi-wei; SONG Yun-hu; HU Sheng-shou


    Severe tricuspid regurgitation with permanent pacemaker wire passing through the orifice of bioprosthetic tricuspid valve is extremely rare. We present a case of such kind of patient and redid bioprosthetic tricuspid valve replacement. A hawk mouth forceps for bone surgery was used to cut off the mental ring of ruined bioprosthetic tricuspid valve and the ruined valve was removed. A new bioprosthetic tricuspid valve was implanted and the wire of permanent pacemaker was left outside the ring of bioprosthetic tricuspid valve. This method may be helpful for such kind of patient.

  7. Mark I 1/5-scale boiling water reactor pressure suppression experiment summary of effects due to vent line orifice variations: air test series

    McCauley, E. W.; Lai, W.; Meier, J.; Stein, W.


    Twenty-seven air tests have been completed in the /sup 1///sub 5/-scale Mark I test facility. The observed effects of vent line orifice variations on the hydrodynamic vertical load function (HVLF) are presented. The conditions for standard tests, to which the orifice variation tests are compared, are defined and discussed. These tests used the ''standard'' or 9.5 inch orifices in the 90/sup 0/ sector vent lines.

  8. A Study of The Elongational Flow of Dilute Polymer Solutions : Estimation of The Elongational Stresses by Utilizing Pressure Drops with Orifice Flows

    福冨, 清; 長谷川, 富市; Fukutomi, Kiyoshi; Hasegawa, Tomiichi


    By assuming a uniformly converging radial flow on the upstream side of an orifice and integrating the equation of motion, an expression was derived to estimate elongational stresses for dilute polymer solutions at the orifice exit from pressure drops between the upstream and downstream of the orifice. The expression shown that the dilute polymer solutions usually give lower values of pressure drop than the solvent (water) does. An experiment was carried out to obtain the pressure drops for th...

  9. Investigation on Effects of Die Orifice Layout on Three-Hole Porthole Extrusion of Aluminum Alloy 6063 Tubes

    Zhang, Cunsheng; Zhao, Guoqun; Chen, Hao; Guan, Yanjin; Cai, Haijin; Gao, Baojie


    Currently, with the increasing demand of high production output, much attention is paid to the research and development of multi-hole extrusion die. However, owing to the complexity of multi-hole porthole extrusion technology, it has not been applied widely in practice for the production of aluminum profiles, especially for porthole die with an odd number of die orifices. The purpose of this study is to design a three-hole porthole die for producing an aluminum tube and to optimize the location of die orifices based on computer-aided design and engineering. First, three-hole extrusion dies for different locations of die orifices are designed. Then, extrusion processes with different multi-hole porthole dies are simulated by means of HyperXtrude. Through numerical simulation, metal flow, temperature distribution, welding pressure, extrusion load, and die stress, etc. could be obtained, and the effects of the location of die orifices on extrusion process are investigated. With the increasing distance between die orifice and extrusion center (described as eccentricity ratio), metal flow becomes nonhomogeneous, and twisting or bending deformation of profile occurs, but the welding pressure rises, which improves the welding quality of profiles. However, the required extrusion force, billet and die temperature, die displacement, and stress induce no significant changes. In comparison with the extrusion force during single-hole porthole extrusion, there is 18.5% decrease of extrusion force during three-hole porthole extrusion. Finally, design rules for this kind of multi-hole extrusion dies are summarized.




    Full Text Available Natural Orifice Transluminal Endoscopic Surgery (NOTES is a new form of minimally invasive surgery which eliminates traditional skin incisions by accessing internal body cavities through natural orifices. In our experimental animal study, we compared the incidences intraperitoneal abscess formation , culture swab of peritoneal cavity positive for organism, intraperitoneal adhesion formation and mean adhesion score before and after lavaging the portal of entry of albino rat , i.e. transgastric and transvaginal. On vaginal route as a portal of entry into peritoneal cavity , on the 7th day , 66% rats developed abscesses , 88% rats had culture swab positive and 88% rats developed intraperitoneal adhesion (grade - 2 before any cleansing of vaginal cavity with antiseptic solution . Now after lavage with povidone iodine solution, only 11% developed abscesses , 22% were peritoneal swab culture positive and 33% had interbowel and parietal adhesion of (grade 0 - 1. On 21 st day , the complication observed was adhesion formation in pre lavage group of 66% incidence and 16% after vaginal lavage. The incidence of complications were reduced significantly after lavage with antiseptic solution as shown by p values (p<0.01 for abscess formation, p< 0.01 for culture positivity and p< 0.01 for adhesions formation. Also the mean adhesion scoring was significantly reduced (p <0.02 after vaginal lavage on the 7 th day. Gastric route as the portal of entry into the peritoneal cavity, again the same variables were compared on the 7th and the 21st day , but wash was given with antibiotic solution (Cefazolin. On the 7th day , 44% had abscesses, 77% were culture positive and 66% had adhesions (Grade 1 - 2 before gastric lavage with antibiotic solution . After wash of stomach, 11% were culture positive and 44% developed adhesions (Grade 0 - 1. Here, abscess formation (p<0.02 and mean adhesion scoring (p<0.05 were significantly reduced after stomach wash. On the 21st day

  11. Bubble Formation at a Submerged Orifice in High-Speed Horizontal Oscillation

    Wang, Ningzhen; Chen, Xiang; Yuan, Jianyu; Wang, Guiquan; Li, Yanxiang; Zhang, Huawei; Liu, Yuan


    Reducing the cell size of aluminum foams is always a hot and difficult topic in the fabrication of aluminum foams by gas injection route. There lacks theoretical guidance for the bubble size reduction when foaming by the dynamic gas injection method. For the convenience of observation, the aqueous bubbles from small-sized orifice in the high-speed horizontal oscillation were investigated in this paper. A bubble formation and detachment model in the high-speed horizontal oscillation system was proposed. The high-speed system with horizontal simple harmonic oscillation could reduce the average bubble size of aqueous foam effectively. The regularity of bubble formation and the influence of experimental parameters on average bubble size can be predicted by the theoretical model, and the experimental results agree well with the theoretical calculation. The results have shown that bubbles generally detach from the orifice at deceleration periods of the simple harmonic oscillation, and there exist several fixed sizes of bubbles with the fixed experimental parameters due to the effects of periodic forces. The average bubble size decreases with the increase of oscillation frequency and amplitude, and it roughly increases with the increase of gas flow rate. Using the high-speed horizontal oscillation method to prepare aluminum foams, the cell size can be reduced to about 1 mm. Moreover, the cell sizes of aluminum foam can be well predicted by this theoretical model.

  12. Experimental study of cooling performance of pneumatic synthetic jet with singular slot rectangular orifice

    Yu, Roger Ho Zhen; Ismail, Mohd Azmi bin; Ramdan, Muhammad Iftishah; Mustaffa, Nur Musfirah binti


    Synthetic Jet generates turbulence flow in cooling the microelectronic devices. In this paper, the experiment investigation of the cooling performance of pneumatic synthetic jet with single slot rectangular orifices at low frequency motion is presented. The velocity profile at the end of the orifice was measured and used as characteristic performance of synthetic jet in the present study. Frequencies of synthetic jet and the compressed air pressure supplied to the pneumatic cylinder (1bar to 5bar) were the parameters of the flow measurement. The air velocity of the synthetic jet was measured by using anemometer air flow meter. The maximum air velocity was 0.5 m/s and it occurred at frequency motion of 8 Hz. The optimum compressed air supplied pressure of the synthetic jet study was 4 bar. The cooling performance of synthetic jet at several driven frequencies from 0 Hz to 8 Hz and heat dissipation between 2.5W and 9W were also investigate in the present study. The results showed that the Nusselt number increased and thermal resistance decreased with both frequency and Reynolds number. The lowest thermal resistance was 5.25°C/W and the highest Nusselt number was 13.39 at heat dissipation of 9W and driven frequency of 8Hz.

  13. Validation of screening examinations of the ureteral orifices in dogs: Comparison of ultrasonography with dissection.

    Balogh, O; Degrandi, F; Hässig, M; Reichler, I M


    In dogs, ultrasonography is performed to locate the ureteral orifices in the urinary bladder, but reference values for their normal location using this technique are missing. In this study, the ureterovesical-vesicourethral and inter-ureterovesical distances were determined in 20 freshly euthanized medium size dogs by detecting artificially produced ureteral jets in color-flow Doppler ultrasonography at two different bladder volumes, and comparing them to manual measurements in the dissected bladder. All distances determined by ultrasonography were in agreement with values found by dissection (P ≥ 0.100). With increasing bladder volume only the left ureterovesical-vesicourethral distance changed (P = 0.041). The right ureteral opening was more cranial than the left in 16 dogs. The inter-ureterovesical distances differed by gender (P = 0.016), but spay/neuter status had no influence (P ≥ 0.847). In conclusion, ultrasonography is a reliable modality for screening ureteral orifices in medium size dogs and agrees with anatomical findings.

  14. Development of a Haptic Interface for Natural Orifice Translumenal Endoscopic Surgery Simulation

    Dargar, Saurabh; Sankaranarayanan, Ganesh


    Natural orifice translumenal endoscopic surgery (NOTES) is a minimally invasive procedure, which utilizes the body’s natural orifices to gain access to the peritoneal cavity. The NOTES procedure is designed to minimize external scarring and patient trauma, however flexible endoscopy based pure NOTES procedures require critical scope handling skills. The delicate nature of the NOTES procedure requires extensive training, thus to improve access to training while reducing risk to patients we have designed and developed the VTEST©, a virtual reality NOTES simulator. As part of the simulator, a novel decoupled 2-DOF haptic device was developed to provide realistic force feedback to the user in training. A series of experiments were performed to determine the behavioral characteristics of the device. The device was found capable of rendering up to 5.62N and 0.190Nm of continuous force and torque in the translational and rotational DOF, respectively. The device possesses 18.1Hz and 5.7Hz of force bandwidth in the translational and rotational DOF, respectively. A feedforward friction compensator was also successfully implemented to minimize the negative impact of friction during the interaction with the device. In this work we have presented the detailed development and evaluation of the haptic device for the VTEST©. PMID:27008674

  15. Effects of Pressure Fluctuation on Flow-Accelerated Corrosion in the Downstream of Orifice Nozzle

    Shakouchi, Toshihiko; Suzuki, Takayuki; Kugimoto, Mitsuo; Tsujimoto, Koichi; Ando, Toshitake

    In the piping system of power plants, pipe wall thinning caused by flow-accelerated corrosion (FAC), liquid droplet impingement (LDI) erosion, and cavitation Erosion (C/E), is a very serious problem because it leads to serious damage and eventual destruction of the piping system [1]-[6]. In this study, pipe wall thinning caused by FAC in the downstream of an orifice nozzle (flow meter) was examined. Experimental Analyses were performed to clarify the characteristics of FAC, its generation mechanism, and the prediction of the thinning and reduction of the pipe wall. The corrosion pattern on the pipe wall was also examined through an experimental simulation. This simulation clarified that the occurrence of thinning mainly depend on the amount of pressure fluctuation p' on the pipe wall. It was also found that the wall thinning rate can be estimated using p' and that the suppression of p' can be realized by replacing the orifice nozzle with a tapered one having an angle to the upstream.

  16. Increasing the stability of nanofluids with cavitating flows in micro orifices

    Karimzadehkhouei, Mehrdad; Ghorbani, Morteza; Sezen, Meltem; Şendur, Kürşat; Pınar Mengüç, M.; Leblebici, Yusuf; Koşar, Ali


    One of the most critical challenges for nanofluids in practical applications is related to their stability and reusability since a gradual agglomeration of nanoparticles in nanofluids occurs with time and is accelerated by heating. In this study, we propose a technique to maintain the performance and stability of nanofluids with the use of cavitating flows through micro orifices to prevent agglomeration and sedimentation of nanoparticles, which will increase the durability of the nanofluids. γ-Al2O3 (gamma-alumina) nanoparticles with a mean diameter of 20 nm suspended in water were utilized. In the current approach, a flow restrictive element induces sudden pressure, which leads to cavitation bubbles downstream from the orifice. The emerging bubbles interact with the agglomerated structure of nanoparticles and decrease its size through hitting or shock waves generated by their collapse, thereby increasing the stability and reusability of nanofluids. The method does not involve any use of expensive surfactants or surface modifiers, which might alter the thermophysical properties of nanofluids, may adversely influence their performance and biocompatibility, and may limit their effectiveness.

  17. 全数字电枢电流控制卷取机恒张力系统%All-Digital Armature Current Controller for Constant Tensile-stress

    孟文博; 孟文涛


    Using 8031 to control armature current for constant tensil-stress reel control system has been studied. The control method for diameter filter and dynamic current filteris is discussed%利用8031实现电枢电流控制的卷取机恒张力控 制,同时研究了卷径滤波、动态电流滤波的必要性和实现方法.该模型已成功地 在工厂使用

  18. Analysis of Lorentz Force Act on Different Shapes Motionless Armature of P-MFCG%静态下 P-MFCG的不同形状电枢受力的仿真

    李鹤; 吕庆敖; 李治源; 陶青青


    活塞式磁通压缩发电机(P-MFCG)作为一种可重复使用的脉冲功率发电机,在电磁发射器的供电电源方面具有广阔的应用前景.发电机电枢上所受的洛伦兹力(电磁力)对发电机的发电效能有至关重要的影响.不同形状的电枢对螺旋线圈内部磁场强度和位形分布的影响不同,在螺旋线圈内所受的洛伦兹力也不同.该文首先对电枢的受力和作用进行了理论分析,得出影响发电效率的是电枢所受洛伦兹力的轴向分量.其次,通过理论计算,得出电枢表面所受轴向力最大时,电枢表面元法向矢量与该处磁感应线矢量应当满足的关系.然后,利用电磁场有限元分析软件Ansoft,对五种不同形状电枢上感应涡流所受的洛伦兹力进行了仿真.所得数据表明圆柱状电枢所受的轴向洛伦兹力最大,锥状次之,是其70%,但都是分布在电枢的棱边上;类半椭球状电枢受力最小,但分布最均匀;而另外两种电枢的形状相比之下没有优势,不可取.这些结论为电枢的优化设计提供了理论依据,也为P-MFCG的进一步研究提供了重要参考.%As a kind of pulse generator, piston-type magnetic flux compression generator ( P-MFCG is suitable for the electromagnetic launcher. The Lorentz force acting on armature influence the generate efficiency.The shape of armature is a critical parameter, which helps to decide the distribution and intensity of magnetic field in helix winding region. With different shapes, the armatures induct different eddy currents and act different magnetic force ( Lorentz force). In this paper, analyzed the force acting on armature when it's sliding, and concluded that the bigger the Lorentz force along axial direction acted on armature, the higher the generate efficiency was. And the Lorentz force along axial direction act on armature was discovered to reach a peak value, only when the normal vector of armature infinitesimal surface and the vector of

  19. Mechanism of non-axisymmetric pipe-wall thinning in pipeline with elbow and orifice under influence of swirling flow

    Fujisawa, Nobuyuki, E-mail: [Visualization Research Center, Niigata University, Niigata (Japan); Kanatani, Nobuaki [Graduate School of Science and Technology, Niigata University, Niigata (Japan); Yamagata, Takayuki, E-mail: [Visualization Research Center, Niigata University, Niigata (Japan); Takano, Tsuyoshi [Graduate School of Science and Technology, Niigata University, Niigata (Japan)


    Highlights: • Pipe-wall thinning due to flow accelerated corrosion is studied. • Pipeline geometry consists of elbow and orifice in swirling flow. • Velocity field and mass transfer rate are measured in pipeline. • Non-axisymmetric pipe-wall thinning occurs behind orifice. - Abstract: In this study, the mechanism of non-axisymmetric pipe-wall thinning that led to a pipeline break in the Mihama nuclear power plant in 2004 is evaluated in a scale-model experiment in a water tunnel having an elbow and orifice under the influence of swirling flow. The velocity fields are measured by stereo particle image velocimetry, and the mass transfer rate is measured by a benzoic acid dissolution method at Reynolds number Re = 3 × 10{sup 4} with and without swirling flow. The non-axisymmetric swirling flow is found to be generated behind the elbow, even when the axisymmetric swirling flow is supplied in the upstream of the elbow. The secondary flow generated in the elbow is not suppressed in the pipeline 10 diameters downstream of elbow in the swirling flow, and in this flow geometry, the non-axisymmetry of the flow is greatly magnified downstream of the orifice. The measured mass transfer rates downstream of the orifice under the influence of swirling flow indicate that the Sherwood number distribution on one side of the pipe is enhanced and that on the other side is reduced owing to the appearance of the non-axisymmetric swirling flow, which results in the occurrence of non-axisymmetric pipe-wall thinning downstream of the orifice.

  20. 电磁发射系统C型固体电枢的电流密度分布特性及其机理分析%Current density distribution characters of C-shaped armature in EML system

    曹昭君; 肖铮


    为得到C型固体电枢的电流密度、焦耳热分布特性,在假设电枢与轨道之间是不分离接触、理想全接触的前提下,基于数值仿真分析了C型电枢的电流密度和温度场分布特性及其产生机理,并进一步探讨了电枢结构尺寸变化对电流密度特性分布规律的影响及其影响机理.得出了集肤效应与邻近效应对电枢的特性分布有重要影响.%In order to realize the Joule heat distribution characters in the process of electromagnetic launch, on the assumption of the nondisjunction and ideal complete contact between the armature and rail, the inner current field distribution and the consequently temperature field distribution characters of C -shaped armature in the launching process were analyzed based on numerical simulation. Furthermore, the effects of the changes in C-shaped armature ' s structure on the inner armature current field distribution and their working mechanism were discussed. Qua-sistatic magnetic and electric fields are applied to explain the distribution characteristic, and the results show that the skin effect and proximity effect have effects upon the distribution character of the armature. The maximum current density was decreased by the increase of the side thickness and front thickness, but the length of the armature had little effect on the maximum current density.

  1. Two-dimensional Numerical Simulation of Melt-wave Erosion in Solid Armatures%固体电枢熔化波烧蚀的二维数值模拟

    巩飞; 翁春生


    为了准确地反映电磁轨道炮内电枢烧蚀的特性,建立了二维固体电枢熔化波烧蚀的计算模型.采用有限差分的交替方向隐式法进行耦合计算,得到了熔化波烧蚀的变化特性.计算结果表明,烧蚀的驱动机制为速度趋肤效应,电流集中在电枢与导轨接触面的尾部边缘,使电枢焦耳热剧增导致出现烧蚀.熔化波从电枢尾部向头部推进,当传至电枢头部时,可能引发电枢转捩.%In order to reflect Armature erosion characteristics in railguns exactly, a computational model of melt-wave erosion in two-dimensional solid armatures is developed. The variation characteristics of melt-wave erosion are obtained adopting coupling calculations by using the Peaceman-Rachford(P-R) format of the finite difference method. The calculation results show that; the driving mechanism of erosion is the velocity skin effect,a concentration of current is at the rear edge of the rail-armature interface, and the erosion occurs due to the joule heating. The melt-wave moves from the back to the front of the armature. It is possible to cause an armature transition when the melt-wave reaches the front of the armature.

  2. Finite Element Analysis of C﹣Shaped Armature with Different Geometric Structure%不同几何结构的C型电枢的有限元分析

    王韬; 侯健; 张绪明


    According to the Maxwell equations,the launching Process of C﹣shaPed solid armatures is stud﹣ied. A static model for E ML is discussed to simulate the three dimension C﹣shaPed armature. In this Pa﹣Per,the solid three﹣dimensional finite element model of a C﹣shaPed armature is established by ANSYS ana﹣lytical software. Several kinds of imProved C﹣shaPed armature are simulated and the results show the distri﹣butions of the magnetic induction intensity,the current density and the temPerature. Analysis of its geo﹣metric structures influence on the electromagnetic ProPerties is made. The research results can Provide the basic theoretical foundations for the armature design and lessen erosion in armature.%根据麦克斯韦方程,对固体电枢电磁发射的过程进行了研究,对电枢在静态模型下的电磁发射进行了模拟。基于ANSYS 建立了固体C型电枢电磁性能的有限元分析模型,对几种改进C型电枢进行了仿真计算,仿真结果显示了固体电枢内部磁感强度、电流密度和温度分布,并研究了电枢几何结构参数改变对电磁性能的影响。研究工作为改进电枢设计,减小电枢烧蚀提供了理论依据。

  3. Noncircular Orifice Holes and Advanced Fabrication Techniques for Liquid Rocket Injectors (Phases 1, 2, 3, and 4)

    Mchale, R. M.; Nurick, W. H.


    A comprehensive summary of the results of a cold-flow and hot-fire experimental study of the mixing and atomization characteristics of injector elements incorporating noncircular orifices is presented. Both liquid/liquid and gas/liquid element types are discussed. Unlike doublet and triplet elements (circular orifices only) were investigated for the liquid/liquid case while concentric tube elements were investigated for the gas/liquid case. It is concluded that noncircular shape can be employed to significant advantage in injector design for liquid rocket engines.

  4. The on Line Way to Detect the Insulation of Armature Windings for DC Generator%直流电机电枢绕组绝缘的在线检测方法



    本文分析了直流电机电枢绕组绝缘劣化直至一点接地时接地电压的变化规律,给出了电枢绕组绝缘的在线检测方法。%The article analyze the roles of the ground voltage varying whenthe insulation of the DC generator is armature winding weakens to one point broken down to ground. Offers the on-line way to detect the insulation of armature windings.

  5. A review on the status of natural orifice transluminal endoscopic surgery (NOTES cholecystectomy: techniques and challenges

    Michael C Meadows


    Full Text Available Michael C Meadows1,3, Ronald S Chamberlain1,2,31Department of Surgery, Saint Barnabas Medical Center, Livingston, NJ, USA; 2Department of Surgery, University of Medicine and Dentistry of New Jersey, Newark, NJ, USA; 3Saint George’s University, School of Medicine, West Indies, GrenadaIntroduction: The evolution of techniques for the performance of a cholecystectomy over the last 25 years has been swift. The laparoscopic approach is now the gold standard for removal of the gall bladder and is the most frequently performed minimally invasive procedure globally. Currently in its infancy stage, natural orifice transluminal endoscopy surgery, or NOTES, is purported to be the next leap forward in minimally invasive approaches. The safety, feasibility, and effectiveness of this procedure, as well as the significance of potential benefits to patients beyond current surgical approaches are yet undetermined.Methods: A comprehensive literature search was conducted using PubMed, a search engine ­created by the National Library of Medicine. Keywords used in the search included “natural orifice transluminal endoscopic surgery”, “NOTES”, “cholecystectomy”, “transcolonic”, “transvaginal”, and “transgastric”. The accumulated literature was critically analyzed and reviewed.Results: One-hundred and eighty-six cases of NOTES cholecystectomies have been published to date. Of these, 174 have been performed through a transvaginal approach. The remainder of the procedures were performed transgastrically. There are no published reports of ­transcolonic cholecystectomies performed in humans. Four of 186 cases (2.15% were converted to traditional laparoscopy due to intraoperative complications. No significant complications or mortalities have been reported.Conclusion: NOTES cholecystectomy appears to be a feasible procedure. However, technical, safety, and ethical issues remain relatively unresolved. Besides improved cosmesis, whether additional

  6. Analysis on Whistling of the Armature Component of Servovalve Based on CFD%基于CFD的伺服阀衔铁组件啸叫分析



      利用Gambit和Fluent对伺服阀衔铁组件的啸叫问题进行CFD分析,模拟计算产品内部油路结构的流固耦合,发现在伺服阀衔铁组件啸叫时,流体在产品内部产生了卡门涡。改变产品的内部结构再次进行CFD模拟计算,卡门涡消除;对该结构的产品进行实际的同压通液测试,伺服阀啸叫的问题得到解决。%By using Gambit and Fluent to carry on the computer flow dynamics (CFD)analysis for the whistling problem of ser-vo valve armature module,the flow and solid coupling in the interior oil duct structure was simulated. It was found that Carmen whorl was produced in the product interior when servovalve armature module whistles. By changing product internal structure and carrying on CFD analog computation once more,the Carmen whorl was eliminated. Through making actual passing fluid test under same pressure to this structures product,the whistling problem of the servo valve is solved.

  7. Parameters for dimensional inspection of orifice plates and roughness of the straight stretches of the tubing

    Alberto Kennedy de Almeida Medeiros


    Full Text Available According to the Technical Regulation of Measurement of Petroleum and Natural Gas (approved in 2000 by ANP - the Petroleum National Agency of Brazil, the systems of measurement of natural gas should use ultra-sonic flow meters, turbines and, especially, the orifice plates, which represent the most expressive base of the flow systems, being used in the fiscal and operational measurements. This work aims to evaluate the parameters that should be accounted for during the dimensional inspection of orifice plate and roughness of the straight stretches of the tubing used for measurement of natural gas, with the objective of guiding the responsible professionals for the measurement of volumes of natural gas by orifice plate, as well as the professionals of calibration laboratories. In this work, minimum specifications are recommended, irrespective of the pressure tapping or orifice type, in agreement with the norms ISO, AGA and the ANP regulations. The influence of these specifications on the parameters used in the calculation of the volumetric flow is also analyzed.Segundo o Regulamento Técnico de Medição de Petróleo e Gás natural (aprovado em 2000, nos sistemas de medições de gás natural devem ser utilizados medidores de vazão tipo ultra-sônico, turbinas e, em especial, as placas de orifício, que representam a base mais expressiva do sistema de vazão, sendo empregadas nas medições fiscais e nas medições operacionais. Este trabalho tem como objetivo avaliar os parâmetros a serem considerados durante a inspeção dimensional de placa de orifício e da rugosidade dos trechos retos de tubulações usados para medição de gás natural, visando orientar os profissionais responsáveis pela medição de volume de gás natural por placa de orifício, como também a profissionais de laboratórios de calibração visando a emissão do certificado de calibração. No trabalho, são recomendadas especificações mínimas, indepen-dentemente do

  8. Manufacturer-provided effective orifice area index charts and the prevention of prosthesis-patient mismatch.

    House, Chad M; Nelson, William B; Kroshus, Timothy J; Dahiya, Ranjan; Pibarot, Philippe


    Prosthesis-patient mismatch (PPM) occurs when an implanted prosthesis is too small relative to the patient's body surface area (BSA). However, mismatch can often be prevented by indexing the expected effective orifice area (EOA) of a prosthesis to the patient's BSA and then selecting the largest implantable prosthesis to avoid mismatch. Previously, prosthesis manufacturers have attempted to simplify this process by providing charts that include the expected EOA for their prosthesis, already indexed into an array of BSA values. One caveat with these charts is that the expected EOA data must truly be reliable, or the charts will misguide the implanting surgeon. Manufacturer-provided charts could be improved by standardizing the EOA data, with one potential source being the hemodynamic data submitted to the United States Food and Drug Administration. This review discusses PPM, manufacturer-provided EOA charts, and the regulation of EOA data.

  9. On the Existence of Subharmonic Screech in Choked Circular Jets from a Sharp-Edged Orifice

    Kandula, Max


    Experiments are performed in choked circular hot and cold nitrogen jets issuing from a 2.44 cm diameter sharp-edged orifice at a fully expanded jet Mach number of 1.85 in an effort to investigate the character of screech phenomenon. The stagnation temperature of the cold and the hot jets are 299 K and 319 K respectively. The axial distribution of the centerline Mach number was obtained with a pitot tube, while the screech data (frequency and amplitude) at different axial and radial stations were measured with the aid of microphones. The fundamental screech frequency of the hot jet is slightly increased relative to that of the cold jet. It is concluded that temperature effects on the screech amplitude are manifested with regard to the fundamental and the subharmonic even at relatively small temperature range considered.

  10. Nucleation of Alpha lactose monohydrate induced using flow through a venturi orifice

    McLeod, J. S.; Paterson, A. H. J.; Bronlund, J. E.; Jones, J. R.


    Nucleation is a determinant of the final crystal size distribution produced during a crystallization process. Other studies in the literature have shown that mixing influences alpha lactose monohydrate nucleation. To investigate this in more detail, three different sized Venturi orifices were used to provide a point of passive mixing for supersaturated lactose solutions. This system allowed the study of different factors associated with characterising the mixing process, including cavitation, power input, Reynolds number and vortex formation. A strong relationship was found between the number of vortices created in the system and the nucleation rate. It is speculated that the vortices decrease the distance required for diffusion of molecules in the system, increasing the rate at which they can come together to form a stable nuclei.

  11. [Appendiceal orifice inflammation in distal ulcerative colitis. Report of a case and review of the literature].

    Tagle, Martin; Scavino, Yolanda; Luna, Eduardo


    We report the case of a 45-year-old female patient with an 18 month diagnosis of distal ulcerative colitis (proctosigmoiditis) of 18 months, who presented initially with allergy to salicylates, for which the disease was managed with corticosteroids and azathioprine and subsequently with Infliximab infusions, entering in remission. When she was about to receive her fifth Infliximab infusion she presented an exacerbation of her underlying disease with frequent stools with mucus, blood and tenesmus. Given that her initial diagnosis was made with a sigmoidoscopy we scheduled a total colonoscopy showing marked inflammation, erythema and friability limited to the recto-sigmoid mucosa, like at the disease onset, and when we reached the cecum an erythematous area circumscribed to the appendiceal orifice was observed, with a mucosal aspect identical to the described for the recto-sigmoid mucosa. The biopsies taken from that area were compatible with ulcerative colitis. We herein describe the details of the case and review the literature.



    The flow characteristics and cavitation effects of water passing through small sharp-edged cylindrical orificesand valves of different shapes in water hydraulics are investigated. The test results using orifices with different aspect ra-tios and different diameters show that the flow coefficients in the case of non-cavitating flow are larger than that of row inthe case of cavitation occurrence. The flow coefficients of flow with cavitation initially decrease as Reynolds number in-creases and ultimately tend to be of constant values close to contraction coefficient. Large aspect ratio has an effect ofsuppressing cavitation. The experimental results about disc valves illustrate that the valves with sharp edge at large open-ing are less affected by cavitation than that at small opening. Throttle with triangle notch has better anti-cavitation abilitythan that with square notch. The flowrate of the throttle with square notch is significantly affected by the flow direction orthe flow passage shape.

  13. Continuous focusing of microparticles using inertial lift force and vorticity via multi-orifice microfluidic channels.

    Park, Jae-Sung; Song, Suk-Heung; Jung, Hyo-Il


    We developed a new microfluidic method for focusing microparticles through the combined use of inertial lift forces and turbulent secondary flows generated in a topographically patterned microchannel. The mechanism of particle focusing is based on the hydrodynamic inertial forces exerted on particles migrating along a non-circular microchannel, i.e.tubular pinch effect and wall effect, which induce particle movement away from walls and along a specific lateral position in the microchannel. With the extraordinary geometry of multi-orifice microchannel, an ordered and focused particle distribution was achieved at central or side regions according to a particle Reynolds number (Re(p)) range. The focusing of particles was controlled by the particle Reynolds number, microchannel length, and volume fraction of particles in suspension. This method will be beneficial in particle focusing processes in a microfluidic device since it offers continuous, high-throughput performance and simple operation.

  14. Minimally invasive surgical technique integrating multiple procedures with large specimen extraction via inguinal hernia orifice

    Mani, Vishnu R.; Ahmed, Leaque


    While laparoscopic surgery can be performed using small skin incisions, any resected specimen must still be able to fit through these opening. For procedures, such as cholecystectomies and appendectomies, this is not usually a problem; however, for large specimens such as bowel or large tumors, this becomes problematic. Currently, the standard technique is to attempt piecemeal removal of the specimen or enlarge one of the laparoscopic incisions, effectively creating a mini laparotomy. Creating a larger incision adds many of the drawbacks of open laparotomy and should be avoided whenever possible. In this article, we present a new technique of combining the repair of an inguinal hernia, umbilical hernia with a duodenal tumor resection in order to extract the specimen through the inguinal hernia orifice. PMID:26703927

  15. Wind tunnel investigation of an all flush orifice air data system for a large subsonic aircraft. [conducted in a Langley 8 foot transonic pressure tunnel

    Larson, T. J.; Flechner, S. G.; Siemers, P. M., III


    The results of a wind tunnel investigation on an all flush orifice air data system for use on a KC-135A aircraft are presented. The investigation was performed to determine the applicability of fixed all flush orifice air data systems that use only aircraft surfaces for orifices on the nose of the model (in a configuration similar to that of the shuttle entry air data system) provided the measurements required for the determination of stagnation pressure, angle of attack, and angle of sideslip. For the measurement of static pressure, additional flush orifices in positions on the sides of the fuselage corresponding to those in a standard pitot-static system were required. An acceptable but less accurate system, consisting of orifices only on the nose of the model, is defined and discussed.

  16. Pure natural orifice transluminal endoscopic surgery (NOTES) with ultrasonography-guided transgastric access and over-the-scope-clip closure

    Donatsky, Anders Meller; Andersen, Luise; Nielsen, Ole Lerberg


    Most natural orifice transluminal endoscopic surgery (NOTES) procedures to date rely on the hybrid technique with simultaneous laparoscopic access to protect against access-related complications and to achieve adequate triangulation for dissection. This is done at the cost of the potential benefits...

  17. Simplified one-orifice venoplasty for middle hepatic vein reconstruction in adult living donor liver transplantation using right lobe grafts.

    Kim, Joo Dong; Choi, Dong Lak; Han, Young Seok


    Middle hepatic vein (MHV) reconstruction is often essential to avoid hepatic congestion and serious graft dysfunction in living donor liver transplantation (LDLT). The aim of this report was to introduce evolution of our MHV reconstruction technique and excellent outcomes of simplified one-orifice venoplasty. We compared clinical outcomes with two reconstruction techniques through retrospective review of 95 recipients who underwent LDLT using right lobe grafts at our institution from January 2008 to April 2012; group 1 received separate outflow reconstruction and group 2 received new one-orifice technique. The early patency rates of MHV in group 2 were higher than those in group 1; 98.4% vs. 88.2% on postoperative day 7 (p = 0.054) and 96.7% vs. 82.4% on postoperative day 14, respectively (p = 0.023). Right hepatic vein (RHV) stenosis developed in three cases in group 1, but no RHV stenosis developed because we adopted one-orifice technique (p = 0.043). The levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in group 2 were significantly lower than those in group 1 during the early post-transplant period. In conclusion, our simplified one-orifice venoplasty technique could secure venous outflow and improve graft function during right lobe LDLT.

  18. In vitro and in vivo evaluation of a novel push-pull osmotic pump with orifices on both side surfaces.

    Li, Wei; Du, Gani; Yang, Xinggang; Zhang, Zhihong; Nie, Shufang; Peng, Bo; Pan, Weisan


    A novel push-pull osmotic pump (PPOP) was developed for delivery of water-insoluble drug gliclazide. Compared to conventional PPOP, which only had orifice(s) on the side of the drug layer, the novel PPOP had orifices of the same diameter on both side surfaces. The in vitro drug-release behavior of both novel PPOP and conventional PPOP were studied and compared; it was found that the drug-release rate of both kinds of PPOP could be influenced by coating level and core hardness whereas orifice size did not have much influence on it, and the study also showed that none of the former factors could influence the similarity of the drug-release profiles of the two kinds of PPOP. Mechanism of drug release from novel PPOP was illustrated using Poiseuille's law of lamina flow, and it was found that under regular formulation, the dissolution profiles of the two kinds of PPOP were similar. In vivo study also showed that the concentration-time profiles of gliclazide in plasma of the two PPOP were comparable and both of them had good in vitro-in vivo correlation. By simply drilled on both side surfaces, the novel PPOP did not need side identification when drilled, so it was more suitable for industrial manufacture than the conventional ones.

  19. Evaluation of Hydrogen Peroxide-Enhanced Endoanal Ultrasound in Detecting the Internal Orifice and Type of Fistula-in-Ano

    M.S Fazeli


    Full Text Available   "n"n Background/Objective: Accurate delineation of the fistula tract anatomy is necessary for surgical management of anal fistulas. Among different ways to do this, endoanal ultrasound (EUS is being increasingly used to evaluate patients with anal fistula. In this study we assessed the accuracy of hydrogen peroxide-enhanced EUS in detecting the internal orifice and the type of the fistula."n"n Patients and Methods: Patients with history and physical examination compatible with fistula-in-ano underwent an injection of 1 ml hydrogen peroxide into the external orifice and then EUS with a 7.5 MHz probe was carried out prior to surgery. The location of the internal orifice, presence of the abscess and the type of the fistula were examined and the results were compared with surgical findings. Results: Thirty-two patients entered the study. The fistula type could be identified in 29 patients (90.6%. Twenty-two (75.8% of these patients had trans-sphincteric  and seven (24.2% had inter-sphincteric fistulas. In 11 (34.3% patients, an abscess was found uring EUS. The fistula type was identified surgically in 29 patients, in which 26 were trans-sphincteric (89.8%, two were inter-sphincteric (6.8%, and one was extra-sphincteric (3.4%. There was a difference between detected sites of internal orifices during EUS and surgery (p value<0.001. Hydrogen peroxide-enhanced EUS had an appropriate agreement in detecting trans-sphincteric fistulas with surgery. Conclusion: Hydrogen peroxide-enhanced EUS is a suitable method for detecting the internal orifice of anal fistulas. It can be used for detecting trans-sphincteric fistulas, which are the most common type.     "n  

  20. Vertebral artery orifice stenosis: a report of 43 cases from northwest iran treated with angioplasty and stenting.

    Mohammadian, R; Najaran, A; Sohrabi, B; Mansourizadeh, R; Mohammadian, F; Nasiri, B; Farhoudi, M


    More than one quarter of all transient ischemic attacks (TIA's) and ischemic strokes involve tissue supplied by the vertebrobasilar (VB) circulation. Vertebral artery stenotic lesion, particularly at the origin of the vertebral artery, is not uncommon but it is a less studied area. Here we present our endovascular treatment experience in a group of patients with vertebral artery orifice stenosis. We enrolled a group of patients with vertebral artery orifice stenosis who presented with confirmed posterior circulation stroke. Vertebrobasilar insufficiency syndrome was confirmed by imaging studies and clinical findings. Vertebral artery stenosis diagnosed by CT or MR Angiography and confirmed by Conventional and digital subtraction angiography (DSA). Angiography was performed by using of femoral or radial artery approach. From October 2008 to January 2010, forty-three consecutive patients (69.8% men) underwent stent placement for symptomatic vertebral artery orifice stenosis. Mean degree of stenosis was 70.45 +/- 7.455 percent and mean age was 71.65 +/- 7.743 years . In the 22 patients (22/43, 51.16%) stenosis were in left side. In the thirty patients (30/43, 69.6%) there was evidence of atherosclerotic disease in the internal carotid artery and in the 23% contra lateral vertebral artery was involved. There were five different cases with left renal artery stenosis especially in the men with left vertebral artery stenosis. Initial technical success rate was 100%. No cerebrovascular complications or embolic events occurred. Six months control angiography follow-up revealed one patient with stent occlusion and moderate (40%) restenosis in the another patient. According to our finding angioplasty and stenting for vertebral artery orifice stenosis is safe and effective. Patients with vertebral artery orifice disease frequently have coexistent atherosclerotic stenosis in the other major extracranial arteries including carotid and renal arteries.

  1. The Female Cibarial Armature of New World Culex, Subgenus Melanoconion and Related Subgenera with Notes on this Character in Subgenera Culex, Lutzia and Neoculex and Genera Galindomyia and Deinocerites (Diptera: Culicidae)


    Subgenus Mieraedes: antiZ&mmagnorum Dyar ( Puerto Rico), bisuzcatus (Coquillett) (Dominican Republic). Subgenus MicrocuZex: eonsozator Dyar the spissipes subtype (spissipes, eprmastasis, opisthopus, por- tesi , taeniopus and vomerifer) based on the cibarial armature as shown here and

  2. 电磁轨道炮电枢接触界面温度场仿真研究%Simulation of Temperature Distribution on Contact Surface of Armature for Electromagnetic Railgun

    李鹤; 雷彬; 吕庆敖; 金龙文


    电磁轨道炮的电枢与轨道界面热特性影响枢轨接触状况和其系统发射性能.对轨道炮枢轨界面的摩擦因数和界面间的接触电阻特性进行分析;建立由焦耳热和摩擦热引起的瞬态温度场仿真模型,并进行有限元求解;依据试验回收电枢的接触表面状况,对电枢接触面经历的温度分布及变化特性进行分析.结果表明:从电枢头部至尾部,焦耳热分布呈现梯度分布,聚集在尾部局部的热量对电枢损伤严重;摩擦热只分布在接触界面的薄层区域内,随着电枢的滑动和磨损,摩擦热耗散在铝熔层上,因而对电枢热性能影响较小.%The contact condition of armature and rail and the launch performance of the system are affected by the thermal characteristic on interface between armature and rail of electromagnetic launching railgun. The friction coefficient and contact resistance of the interface were analyzed, the simulation models for Joule heat and friction heat were established to simulation the transient thermal distribution, and combining with tested armature, the temperature distribution characteristic was analyzed. The results show that the Joule heat in armature shows a gradient distribution from head to rear,and the heat congregating in rear of armature causes the damage of material severely. The friction heat only distributes in the thin layer of contact face,and along with armature sliding and wearing,friction heat dissipates on aluminum melt film,and thus,has little effect on armature performance.

  3. 同步感应线圈炮圆筒型电枢几何结构优化%Optimization of Geometric Structure for Armature in Synchronous Induction Coilgun

    邹本贵; 曹延杰; 李瑞峰; 王旻


    电枢是同步感应电磁线圈炮中的一个关键部件,电枢的结构是影响同步感应电磁线圈炮发射效率的重要因素.建立了同步感应线圈炮电枢磁-结构耦合的数学模型,以电枢总体积为目标函数,建立了基于设计变量、约束条件和收敛准则的圆筒型电枢结构优化数学模型.利用Ansys基于APDL的有限元优化技术进行优化求解,得到了电枢的最佳设计变量,仿真结果表明该设计变量既能满足电枢的几何约束条件和性能约束条件,又使电枢体积较初值减小了78.89%,有效地降低了电枢在弹丸中的配重.%Armature is a key component of synchronous induction coilgun (SICG). Structure of the armature do have some effect on the efficiency during the launching process of SICG. A mathematical model of magnetic-structural coupling of the armature was built. The overall volume of the armature was defined as objective function. Set up a mathematical model of structural optimization consisted of design variables, constraint conditions and convergence criterion. The optimization solution was obtained by parameterized finite element analysis of Ansys based on APDL and the optimal design variables were obtained. The simulation results show that the new design variables can meet the constraint conditions of the armature and the decrease in volume of the armature is almost 78. 89 percent. So the proportion of the armature weight in projectile is reducing effectively.

  4. Is the water flow more or less than that predicted by the Navier-Stokes equation in micro-orifices?

    Hasegawa, Tomiichi; Ushida, Akiomi; Narumi, Takatsune; Goda, Masaki


    Micro-fluid mechanics is an important field in modern fluid mechanics. However, flows through microscale short tubes (micro-orifices) are not yet fully understood. Thus far, experiments on the flow through micro-orifices have been conducted by two methods: the pressure-given method (PGM), in which the pressure is given and the rate of flow is measured, and the flow-given method (FGM), in which the flow rate is given and the pressure is measured. According to conventional fluid mechanics, these two methods should give the same result; however, studies have found lower fluidity (lower flow rate) in PGM and higher fluidity (lower pressure drop) in FGM than that predicted by the Navier-Stokes equation, suggesting that the difference is caused by the method used. To clarify the cause of this difference, we examined the flow of ultra-pure water (UPW) with elapsed time by PGM. UPW was passed through Ni or Ti micro-orifices with 20-μm diameter at applied pressures of 50-1000 Pa. The difference in the shape and material of the orifices did not have a great effect on the flow property. The flow rate was frequently higher than that predicted at the start of the flow experiment; however, it subsequently fell and finally reached zero as time elapsed. This fact suggests that UPW inherently flows at velocities higher than those predicted by the Navier-Stokes equation; however, the flow is then resisted by something that develops over time. We removed an orifice in which flow had stopped from the experimental apparatus, observed it by phase contrast microscope and electron probe micro analyzer, and revealed that a visible membrane, a transparent lattice-like structure, or nothing existed in the orifice. Dissolved air was reduced by deaerating the air from UPW (deaeration), bubbling UPW with Ar (Ar-bubbling), or preventing UPW from contact with air after UPW production (air-prevention). Deaeration, Ar-bubbling, and air-prevention reduced the probability of formation of the visible

  5. 基于灰熵分析法的电枢出口速度影响因素分析%Analysis on Factors Influencing Muzzle Velocity of Armature Based on Grey Relation Entropy Method

    张祎; 杨春霞; 栗保明


    为了研究电磁轨道炮结构设计参数与电枢出口速度之间的相关性,建立了电磁轨道炮电枢出口速度影响因素的指标体系,采用灰熵关联法,分析了电容、电感、电阻、电枢质量、轨道有效长度、放电电压对某口径电磁轨道炮电枢出口速度散布特性影响的显著程度.结果表明,放电电压、电容是影响电磁轨道炮精度的主要因素,电枢质量时电磁轨道炮精度影响最小,这为提高电磁发射系统的优化设计提供了科学依据.%In order to study the relationship between the design parameters of electromagnetic railgun(EMG)and the velocity of armature, the index system of factors affecting the velocity of armature was built. By using grey relation entropy method, the significance of factors influencing the scattering of armature's muzzle velocity, including capacitance, inductance, resistance,armature's mass,effective length of railgun and charge voltage, was analyzed. The result shows that the main factors affecting the accuracy of EMG are discharge voltage and capacitance,and the effect of armature's mass on the accuracy of EMG is the smallest. The result offers scientific evidence for optimization design of EMG system.

  6. Shape Design and Contact Stress Analysis of H-shape Solid Armature%H 形固体电枢形状设计及接触应力分析

    刘峰; 党晟罡; 赵丽曼; 王振春; 温银堂


    Armature is one of the key components of the electromagnetic railgun.Its design and improvement plays a significant role in the development of electromagnetic launcher.The con-trol equations of armature shape were proposed considering the mechanical and electromagnetic requirements.The armature mechanical model was determined by the control equations based on finite element analysis.The mechanical model was improved based on the calculation re-sults.The results show that the deformation and stress of new H-shape armature can satisfy the requirements of structure design.At the same time,the pressure between the armature and the electromagnetic rail can guarantee better contact between them.%电枢作为电磁轨道炮的核心部件之一,它的设计与改进一直在发展电磁发射装置中占据重要位置。考虑力学和电磁场的要求,建立了电枢形状的控制方程;并对由控制方程确定的电枢力学模型进行了有限元分析,由计算结果对力学模型进行了改进。改进模型的计算结果表明,新型 H 形电枢的变形以及应力状态满足结构设计要求,同时电枢与轨道之间的压力也能够保证导轨与电枢的良好接触。

  7. Dielectrophoresis-assisted massively parallel cell pairing and fusion based on field constriction created by a micro-orifice array sheet.

    Kimura, Yuji; Gel, Murat; Techaumnat, Boonchai; Oana, Hidehiro; Kotera, Hidetoshi; Washizu, Masao


    In this paper, we present a novel electrofusion device that enables massive parallelism, using an electrically insulating sheet having a two-dimensional micro-orifice array. The sheet is sandwiched by a pair of micro-chambers with immersed electrodes, and each chamber is filled with the suspensions of the two types of cells to be fused. Dielectrophoresis, assisted by sedimentation, is used to position the cells in the upper chamber down onto the orifices, then the device is flipped over to position the cells on the other side, so that cell pairs making contact in the orifice are formed. When a pulse voltage is applied to the electrodes, most voltage drop occurs around the orifice and impressed on the cell membrane in the orifice. This makes possible the application of size-independent voltage to fuse two cells in contact at all orifices exclusively in 1:1 manner. In the experiment, cytoplasm of one of the cells is stained with a fluorescence dye, and the transfer of the fluorescence to the other cell is used as the indication of fusion events. The two-dimensional orifice arrangement at the pitch of 50 μm realizes simultaneous fusion of 6 × 10³ cells on a 4 mm diameter chip, and the fusion yield of 78-90% is achieved for various sizes and types of cells.

  8. Balancing Vibrations at Harmonic Frequencies by Injecting Harmonic Balancing Signals into the Armature of a Linear Motor/Alternator Coupled to a Stirling Machine

    Holliday, Ezekiel S. (Inventor)


    Vibrations at harmonic frequencies are reduced by injecting harmonic balancing signals into the armature of a linear motor/alternator coupled to a Stirling machine. The vibrations are sensed to provide a signal representing the mechanical vibrations. A harmonic balancing signal is generated for selected harmonics of the operating frequency by processing the sensed vibration signal with adaptive filter algorithms of adaptive filters for each harmonic. Reference inputs for each harmonic are applied to the adaptive filter algorithms at the frequency of the selected harmonic. The harmonic balancing signals for all of the harmonics are summed with a principal control signal. The harmonic balancing signals modify the principal electrical drive voltage and drive the motor/alternator with a drive voltage component in opposition to the vibration at each harmonic.

  9. Preparation and evaluation of mucoadhesive simvastatin microcapsules using orifice gelation technique

    Trishna Bal


    Full Text Available Preparation and characterization of Simvastatin/ Hydroxy propyl beta cyclodextrin (HPBCD (SV/HPBCD binary systems by co-grinding technique and formulating the binary system in oral mucoadhesive microcapsules by using hydrophilic sodium alginate (SA and another plant seed mucilage dillenia (obtained from Dillenia indica, Family, Dilleniaceae using orifice gelation technique and systematically evaluating in vitro by using scanning electron microscopy (SEM, fourier transform infrared spectroscopy (FTIR, differential scanning calorimetry (DSC, and X-ray diffractometer (XRD. The microcapsules were smooth and elegant in appearance showed no visible cracks as confirmed by SEM; and extended drug release of 72.682% upto 12 hours in phosphate buffer of pH 6.8; showing particle size within the range of 371.5-457 μm, and less angle of repose, Hausner′s ratio and Carr′s consolidation index; and showed encapsulation efficiency of 63.068 ± 0.002 to 99.083 ± 0.017%. The in vitro release data of optimized batch of microcapsules were plotted in various kinetic equations to understand the mechanisms and kinetics of drug release, which followed zero order kinetics and value of "n," is calculated to be 0.505 and drug release was diffusion controlled. The in vivo antihyperlipidemic activity of formulations in mice was carried out developing hyperlipidemia in mice and then administering the optimized formulations orally, and the formulation showed promising results.

  10. Does bladder outlet obstruction affect distance between the ureteric orifices in patients with benign prostate hyperplasia?

    Cüneyt Özden


    Full Text Available Objectives: Many morphological changes occur in the bladder due to bladder outlet obstruction (BOO in pa-tients with benign prostate hyperplasia (BPH. In the present study we evaluated the relationship between in-terureteric distance (IUD of the orifices and BOO in BPH patients.Materials and methods: Thirty-seven consecutive pa-tients with lower urinary tract symptoms at the urology polyclinic included in the study. Patients divided into 2 groups according to maximal flow rate (Qmax. The first group constituted of 18 patients with Qmax 15ml/s. The IUD measurement was performed with Doppler ultrasonography.Results: There was no significant difference between the groups regarding mean age and prostate volume. Mean IUD in the first group was 32.7±5.4 mm and mean IUD in the second group was 31.5±5.1 mm. There was no statistically significant difference between the groups regarding the IUD.Conclusions: Data obtained from the study revealed that measurement of IUD with Doppler ultrasonography not significantly related to BOO.

  11. Microendoscopy of the nasal cavity and the paranasal sinuses via their natural orifices

    Linnarz, Marietta; Hopf, Juergen U. G.; Gundlach, Peter; Scherer, Hans H.; Loerke, S.; Voege, Karl H.; Lutze-Koffroth, C.; Tschepe, Johannes; Mueller, Gerhard J.


    Microendoscopy of the nasal cavities and the para-nasal sinuses is a new and atraumatical method to investigate these anatomical regions which were previously inaccessible for direct visual inspection due to their special topography. By means of superfine flexible and partly actively tip controllable fiberscopes the procedure only requires local anesthesia. Microendoscopes with outside diameters of 290 to 1600 micrometers are inserted through the natural orifices or ducts of the para-nasal sinuses partly guided by actively steerable microcatheters of 5 to 9 F. The eyepiece of the scope is connected with a chip-camera simultaneously carrying the endoscopic images onto a monitor system. This new procedure contributes to a better presurgical planning and risk assessment of endonasal sinus surgery and to the avoiding of repeated x-ray imaging during the therapeutic follow up of acute and chronic para-nasal infections. Furthermore, in combination with fiber delivered laser systems, it forms the basis and technical precondition for `minimal invasive laser-assisted microsurgery' of these anatomic regions.

  12. Natural orifice translumenal endoscopic surgery: Progress in humans since white paper

    Byron F Santos; Eric S Hungness


    Since the first description of the concept of natural orifice translumenal endoscopic surgery (NOTES), a substantial number of clinical NOTES reports have appeared in the literature. This editorial reviews the available human data addressing research questions originally proposed by the white paper, including determining the optimal method of access for NOTES, developing safe methods of lumenal closure, suturing and anastomotic devices,advanced multitasking platforms, addressing the risk of infection, managing complications, addressing challengeswith visualization, and training for NOTES procedures.An analysis of the literature reveals that so far transvaginal access and closure appear to be the most feasible techniques for NOTES, with a limited, but growing transgastric, transrectal, and transesophageal NOTES experience in humans. The theoretically increased risk of infection as a result of NOTES procedures has not been substantiated in transvaginal and transgastric procedures so far. Development of suturing and anastomotic devices and advanced platforms for NOTES has progressed slowly,with limited clinical data on their use so far. Data on the optimal management and incidence of intraoperative complications remain sparse, although possible factorscontributing to complications are discussed. Finally, this editorial discusses the likely direction of future NOTES development and its possible role in clinical practice.

  13. Natural orifice transendoluminal surgery and laparoendoscopic single-site surgery: the future of laparoscopic radical prostatectomy.

    Barret, Eric; Sanchez-Salas, Rafael; Ercolani, Matthew C; Rozet, Francois; Galiano, Marc; Cathelineau, Xavier


    Techniques for minimally invasive radical prostatectomy (RP) have been carefully reviewed by surgical teams worldwide in order to identify possible weaknesses and facilitate further improvement in their overall performance. The initial plan of action has been to carefully study the best-practice techniques for open RP in order to reproduce and standardize performance from the laparoscopic perspective. Similar to open surgery, the learning curve of minimally invasive RP has been well documented in terms of objective evaluation of outcomes for cancer control and functional results. Natural orifice transluminal endoscopic surgery (NOTES) and laparoendoscopic single-site surgery (LESS) have recently gained momentum as feasible techniques for minimal access urological surgery. NOTES-LESS drastically limit the surgeon's ability to choose the site of entry for operative instruments; therefore, the advantages of NOTES-LESS are gained with the understanding that the surgical procedure is more technically challenging. There are several key elements in RP techniques (in particular, dorsal vein control, apex exposure and cavernosal nerve sparing) that can have significant implications on oncologic and functional results. These steps are hard to perform in a limited working field. LESS radical prostatectomy can clearly be facilitated by using robotic technology.


    Aynur ŞENOL


    Full Text Available Investigations to develop data for this study were made using a pilot scale glass column of 9 cm inside diameter randomly filled to a depth of 1.90 cm with a Raschig type ring at a slightly modified geometry. The geometrical characteristics of packing are: the total area of a single particle ad = 2.3 cm2; specific area ap = 10.37 cm2/cm3; voidage ? = 0.545 m3/m3. The efficiency tests were run using trichloroethylene/n-heptane system under total reflux conditions. Using the modified versions of the Eckert flooding model and the Bravo effective area (ae approach, as well as the Onda wetted area (aw and individual mass transfer coefficient models, it has been attempted to estimate the packing efficiency theoretically. This article also deals with the design strategies attributed to a randomly packed column. Emphasis is mainly placed on the way to formulate an algorithm of designing a pilot scale column through the models being attributed to the film theory. Using the column dry pressure drop properties based on the air flowing it has been achieved a generalized flow rate approach for calibrating of an orifice through which the air passes.

  15. Vortex Simulation of Axisymmetrical Flows in Cylindrical Geometries.Part II:Application to Pipes Incorporating an Orifice Plate


    The Random Vortex Method extended to an axisymmetrical flow is used in the study of the flow field inside pipes incorporating an orifice plate with different contraction ratios and different inlet velocity profiles.Three test-cases,each having experimental measurements available in the literature,are studied,.In particular,instantaneous and average velocity fields along with the turbulent statistics for high Reynolds number flows are computed and compared to the corresponding experimental results These comparisons show the ability and the limitations of the method.The results of the numerical simulations are used in the physical analysis of the flow fields and thus allow for a better understanding of the dynamics of the flow in pipes incorporating an orifice plate.

  16. An Analytical Solution of the Potential Velocity Field Induced by a Growing Bubble from a Plate Orifice

    ZhiTao; NingKang


    An analytical solution is derived with the mirror image method of the velocity field of an inviscid liquid induced by a growing bubble from a plate orifice.The flow is assumed potential,and the bubble shape is idealised as sphercal.In deriving the motion equation,the spherical image of a point source,which is a combination of a point source and a line source,is proved approximate to a double source,This approximation enables continuation of the effectiveness of mirror image method to the case studied in this paper.The derived velocity potential equation is verified for the boundary conditions on the bubble surface and the orifice plate.The streamlines of the velocity field are presented and compared with experimental results in the literature.

  17. Estimation of Regurgitant Volume and Orifice in Aortic Regurgitation Combining CW Doppler and Parameter Estimation in a Windkessel Like Model

    Bjørn A.J. Angelsen


    Full Text Available A method for noninvasive estimation of regurgitant orifice and volume in aortic regurgitation is proposed and tested in anaesthesized open chested pigs. The method can be used with noninvasive measurement of regurgitant jet velocity with continuous wave ultrasound Doppler measurements together with cuff measurements of systolic and diastolic systemic pressure in the arm. These measurements are then used for parameter estimation in a Windkessel-like model which include the regurgitant orifice as a parameter. The aortic volume compliance and the peripheral resistance are also included as parameters and estimated in the same process. For the test of the method, invasive measurements in the open chest pigs are used. Electromagnetic flow measurements in the ascending aorta and pulmonary artery are used for control, and a correlation between regurgitant volume obtained from parameter estimation and electromagnetic flow measurements of 0.95 over a range from 2.1 to 17.8 mL is obtained.

  18. Numerical Study on Turbulent Forced Convection and Heat Transfer Characteristic in a Circular Tube with V-Orifice

    Withada Jedsadaratanachai


    Full Text Available Performance assessments on heat transfer, pressure loss, and thermal enhancement factor in the circular tube heat exchanger inserted with the V-orifices are investigated numerically. The influences of the blockage ratio, gap spacing ratio, and orifice arrangement are reported for turbulent regime, Re=3000–10,000. The finite volume method and SIMPLE algorithm are selected to solve the present problem. The mechanisms on flow and heat transfer characteristics are described. The periodic concepts on flow and heat transfer are also studied. The numerical results show that the gap spacing ratio is main reason for the changes of the flow and heat transfer topologies. The gap distance helps to adjust the optimum point of the thermal performance, especially at high flow blockage ratio. In addition, the optimum thermal performance of the present system is around 2.25 at the lowest Reynolds number, Re=3000.

  19. Numerical simulation of particle dynamics in an orifice-electrode system. Application to counting and sizing by impedance measurement.

    Isèbe, Damien; Nérin, Philippe


    This paper describes how to numerically tackle the problem of counting and sizing particles by impedance measurement in an orifice-electrode system. The model allows to simulate the particle dynamics submitted to strong hydrodynamic stresses through a microorifice and to compute the voltage pulses generated by the modification of the inner dielectric medium. This approach gives important information about particles size distribution and allows to quantify the role of trajectory and orientation of particles on the size measurement.

  20. Separation of nanoparticles by a nano-orifice based DC-dielectrophoresis method in a pressure-driven flow.

    Zhao, Kai; Peng, Ran; Li, Dongqing


    A novel DC-dielectrophoresis (DEP) method employing a pressure-driven flow for the continuous separation of micro/nano-particles is presented in this paper. To generate the DEP force, a small voltage difference is applied to produce a non-uniformity of the electric field across a microchannel via a larger orifice of several hundred microns on one side of the channel wall and a smaller orifice of several hundred nanometers on the opposite channel wall. The particles experience a DEP force when they move with the flow through the vicinity of the small orifice, where the strongest electrical field gradient exists. Experiments were conducted to demonstrate the separation of 1 μm and 3 μm polystyrene particles by size by adjusting the applied electrical potentials. In order to separate smaller nanoparticles, the electrical conductivity of the suspending solution is adjusted so that the polystyrene nanoparticles of a given size experience positive DEP while the polystyrene nanoparticles of another size experience negative DEP. Using this method, the separation of 51 nm and 140 nm nanoparticles and the separation of 140 nm and 500 nm nanoparticles were demonstrated. In comparison with the microfluidic DC-DEP methods reported in the literature which utilize hurdles or obstacles to induce the non-uniformity of an electric field, a pair of asymmetrical orifices on the channel side walls is used in this method to generate a strong electrical field gradient and has advantages such as capability of separating nanoparticles, and locally applied lower electrical voltages to minimize the Joule heating effect.

  1. Visualization of the Light-Emitting Region from Cavitation in Circular Orifice Flows by the Photon Counting Method

    田部井, 勝稲; 白井, 紘行; 高草木, 文雄


    Emission experiments on cavitation bubbles in water were performed with circular orifice flows. The region emitting faint light due to the bubbles was visualized with the combined method of photon counting and computerized tomography. Emission data obtained from outer-side observation were inverted into internal intensity distributions by means of the modified Abel transformation in which the light-quenching effect by cavitation bubbles was taken into account. It was observed that, under the ...

  2. Spectral and electrical diagnosis of complex space-charge structures excited by a spherical grid cathode with orifice

    Schrittwieser, R. W.; Ionita, C.; Teodorescu-Soare, C. T.; Vasilovici, O.; Gurlui, S.; Irimiciuc, S. A.; Dimitriu, D. G.


    Optical emission spectroscopy and Langmuir probes were used to diagnose complex space-charge structures that appear inside and around a spherical grid with orifice applying a negative voltage below a critical value to it. Measurements (through the orifice) delivered the axial profiles of plasma potential, electron temperature and density, and of the densities of excited atoms and ions. Thereby the formation of a double layer was found in the region near the orifice with a potential drop close to the ionisation potential of the applied gas, confirming the presence of a fireball in that region (also evidenced by visual observation), i.e. of a quasi-spherical bright plasma region consisting of a positive core (an ion-rich plasma) confined by a double layer. Spectral investigations confirmed the presence of high ion density inside the spherical grid (due to the hollow cathode effect), while outside the grid a transition region with a strong rate of ionisation and excitation processes appears. Information on the nonlinear dynamics of this space-charge structure was obtained from the analysis of the oscillations of the discharge current, as well as of the floating potential inside and outside the spherical grid. Dedicated to Hans Pécseli at the occasion of his 70th birthday, an extraordinary plasma physicist and a wonderful, noble and warm-hearted friend for more than 40 years.

  3. A case of pericecal hernia with a hernial orifice located on the lateral side of the cecum.

    Nishi, Takayuki; Tanaka, Yoichi; Kure, Tetsujin


    The patient was a female in her 70s without previous laparotomy who visited our hospital for right lower abdominal pain. Marked small intestinal gas was noted on plain abdominal X-ray radiography. The patient was diagnosed with ileus and admitted. On contrast imaging through an ileus tube inserted for decompression, the small intestine was obstructed in the right lower abdominal region, and emergency laparotomy was performed. A hernial orifice was present on the lateral side of the cecum, and the small intestine was partially incarcerated, based on which a pericecal hernia was diagnosed. Since no circulatory disorder was noted in the incarcerated intestine, only reduction was performed without enterectomy. The hernial orifice was left open, considering that there was no possibility of re-incarceration. The postoperative course was favorable, and the patient was discharged on the 7th hospital day. Since this was a rare pericecal hernia case of internal hernia, we searched for and reviewed cases reported in Japan. This was a very rare case with a hernial orifice located on the lateral side of the cecum, not included in the current classification of pericecal hernia.

  4. The Effect of Orifice Diameter to the Acoustic Signals Captured at the Cold Part of a Ranque-Hilsch Vortex Tube

    Wisnoe Wirachman


    Full Text Available In this study, acoustic analysis and thermofluid performance of a Ranque-Hilsch Vortex Tube (RHVT is experimentally investigated under different orifice diameters at its cold tube. The orifice diameters used are 2mm, 3 mm, 4 mm, 5 mm and 6 mm. The inlet pressure (gage is set at 10 psi, 15 psi, 20 psi and 25 psi for each orifice diameter. The sound produced by the tube is recorded using a microphone located outside the cold tube. The acoustic signal is processed using Fast-Fourier Transform (FFT to obtain the frequency representation. Main frequencies are then extracted to constitute the signature of the signal for that specific configuration. It is observed that different orifice diameters give different signatures. These signatures are then associated with the thermofluid performance of the device to obtain the relation among the parameters.

  5. 电磁轨道炮电枢-导轨接触表面状况数值研究%Numerical study of armature-rail contact interfacial conditions in electromagnetic railguns

    巩飞; 翁春生


    为了了解电磁轨道炮电枢-导轨接触表面的电热特性,采用接触表面热流量模型,利用有限差分法模拟了非理想电接触的热效应。研究了不同结构的电枢对接触压力和接触表面温升过程的影响以及摩擦对电枢运动状态的影响。计算结果表明:C 型电枢与块状电枢相比可以提供更高的接触压力,其接触表面温度峰值更低,降幅达到31%,温度分布更加均匀;电枢的臂角角度降低15°,接触表面的温度峰值下降超过10%;摩擦延缓了电枢运动,速度下降约9%,不利于提高发射效率。%To understand the electrothermal properties of the armature-rail electrical contact interfaces in electromagnetic railguns exactly, the thermal effect of imperfect electrical contact (ImPEC) is modeled using the contact heat flux model and finite difference method. The friction effect and the effects of different geometry of armatures on the contact force and temperature rise are studied. The calculation results show that the C-shape armature can provide a higher contact force than the block one. The maximum temperature of the contact interface decreases by 31% ,and the temperature distribution is more uniform in the C-shape armature. With a decrease of 15° in the rear angle of the armature,the maximum temperature of the contact interface decreases by more than 10% . The friction delays the motion of the armature and the velocity decreases by 9% ,which is un-favorable for the transmitting efficiency.

  6. Features of localization coronary arterial orifices and angles of origin their proximal segments in usually formed hearts and with transposition of the great vessels

    Malov A.E.


    The work purpose was revealing of features of localization coronary arterial orifices, angles of origin and acourse of their proximal segments in usually formed hearts and with transposition of the great vessels. Research is executedon 31 specimens of usually formed hearts and 31 specimens with transposition of the great vessels. For the estimation ofposition the orifices in aortic sinuses and orientation of a course of proximal segments of coronary arteries the morphologicalresearches was ca...

  7. Evaluation of endoscopy in localizing transgastric access for natural orifice transluminal endoscopic surgery in humans.

    Linke, Georg R; Zerz, Andreas; Kapitza, Florian; Warschkow, Rene; Lange, Jochen; Meyenberger, Christa M; Binek, Janek


    To date, transgastric access in humans for natural orifice transluminal endoscopic surgery (NOTES) has been poorly evaluated. To compare endoscopic visualization of the transgastric access point with the laparoscopically defined ideal entrance to the peritoneal cavity. Prospective pilot study in humans. Single tertiary-care center. This study involved 31 patients referred for laparoscopic cholecystectomy. Access points were marked by endoscopy alone, endoscopy combined with diaphanoscopy, and endoscopy after pneumoperitoneum. Points were correlated with a laparoscopically visualized, previously defined ideal access area. To choose the appropriate access point within the laparoscopically defined ideal access area to the peritoneal cavity away from major vessels and adjacent organs, by using endoscopy and to establish landmarks for the endoscopist, look for a learning curve, and identify potential problems. The percentage of access points within the laparoscopically defined ideal area was 35.5% with endoscopy alone, 13.8% using the diaphanoscopy method, and 45.2% after transcutaneous pneumoperitoneum. A safe access point (> or = 3 cm from major gastric vessels) could be achieved with the 3 techniques in 83.9%, 65.5%, and 87.1% of patients, respectively. A positive learning curve for endoscopic localization was identified before (P = .008) and after (P = .014) pneumoperitoneum. Virtual complications were greater in obese patients. This was a small pilot study with hypothetical complications and problems, because actual transgastric access was not performed. The criteria for an ideal access area were very strict. Endoscopy, especially with the use of pneumoperitoneum, can reliably locate a safe transgastric entrance point. However, the endoscopically chosen site correlates poorly with the ideal laparoscopically determined site for transgastric access. 2010 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

  8. [Identification of internal fistolous orifice: evolution of methylene blue technique with a mini-probe].

    Gaj, F; Andreuccetti, J; Trecca, A; Crispino, P


    Often perianal fistulas can be difficult typing and traditional anatomical classifications do not help the surgeon in accurate diagnosis of the fistula as an outpatient procedure and therefore does not allow a timely surgical currettage. The aim of our study was to introduce in the management of anal fistulas performed on an outpatient injection with methylene blue of the fistula through a small polyethylene catheter in order to detect in real time the internal opening of the fistula and drive so the next currettage surgery. A total of 50 consecutive patients 21 female and 29 male, relating to our clinic with symptoms suggestive of colon proctology perianal fistula, aged between 36 and 69 years were selected for our study. After running the news-gathering medical history, physical examination, digital examination through examination anoscope, using a polyethylene catheter in a small scale, of methylene blue was injected through the external fistula orifice looking inside the spreading of liquid. Subsequently, the patient was started on specillazione currettage and possible surgery. 62 outpatients were treated intramural fistulas, diagnosed with the injection technique with methylene blue running always probing and practiced a wide dish made of the mucosa, submucosa and circular muscle layer of the internal drainage with sphincterotomy. In particular, the technique injection of methylene blue was sufficient to diagnose 42 out of 62 cases examined (67.7%). In the remaining 20 cases it was necessary to integrate diagnosis with MRI-defecates on the complexity of fistulas (10 horseshoe, 6 trans sphincteric and 4 intersphincteric. Methylene blue injection is a low-cost screening technique, simple to perform on an outpatient basis and in the case of suprasphincteric fistulas also a simple diagnostic technique is sufficient to allow the closure of the fistula.

  9. S-IV-B Aft Swing Arm Hydraulic With Drain System Orifice Valve


    The Marshall Space Flight Center (MSFC) played a crucial role in the development of the huge Saturn rockets that delivered humans to the moon in the 1960s. Many unique facilities existed at MSFC for the development and testing of the Saturn rockets. Affectionately nicknamed 'The Arm Farm', the Random Motion/ Lift-Off Simulator was one of those unique facilities. This facility was developed to test the swing arm mechanisms that were used to hold the rocket in position until liftoff. The Arm Farm provided the capability of testing the detachment and reconnection of various arms under brutally realistic conditions. The 18-acre facility consisted of more than a half dozen arm test positions and one position for testing access arms used by the Apollo astronauts. Each test position had two elements: a vehicle simulator for duplicating motions during countdown and launch; and a section duplicating the launch tower. The vehicle simulator duplicated the portion of the vehicle skin that contained the umbilical connections and personnel access hatches. Driven by a hydraulic servo system, the vehicle simulator produced relative motion between the vehicle and tower. On the Arm Farm, extreme environmental conditions (such as a launch scrub during an approaching Florida thunderstorm) could be simulated. The dramatic scenes that the Marshall engineers and technicians created at the Arm Farm permitted the gathering of crucial technical and engineering data to ensure a successful real time launch from the Kennedy Space Center. This photo depicts a close up view of the S-IV-B aft swing arm hydraulic with drain system orifice valve.

  10. 关于直流力矩电机电枢灌封后胶层开裂问题的探析%Study on Crack of DC Torque Motor's Armature After Sealed with Epoxy Resin

    罗润娟; 周钦沅; 董文生


    直流力矩电机电枢用环氧树脂灌封后胶层开裂的问题是直流力矩电机在生产制造过程中较为常见的一种问题.本文从灌封料配方及其它因素去分析,解决该类电机电枢灌封开裂.%In the producing of DC torque motor's armature,it's a usual problem about the glue layer cracking after sealed with epoxy resin. This problem was analyzed from sealing compounds to other factors in this paper,so as to solve the crack of this kind of motor's armature.

  11. Analytical Study on Calculating Armature-reaction Field of Salient PMSM with Eccentric Rotor%转子偏心凸极永磁电机电枢磁场解析研究

    曹晴; 李槐树; 周羽; 周石


    Models based on Schwarz–Christoffel's transformation of a salient PMSM with rotor eccentricity is presented. At first, motor's direct-quadrature (d-q) axis's armature-reaction field under square wave magnetomotive force is calculated. Then, d-q armature-reaction field under magnetomotive force without regular distribution is analyzed. Finally, armature-reaction field can be obtained by superposing them. This method can be applied to magnet calculation of different types of motors with rotor eccentricity. Armature-reaction field of this motor was calculated by using this analytical method and Finite Element Method (FEM). The results shows that the two cases agree well, and the validity and accuracy of the presented method are verified.%本文基于许-克变换针对转子偏心凸极永磁电机建立了磁场计算模型.首先计算方波磁势作用下电机的直、交轴电枢磁场;然后计算不规则磁势分布条件下的直、交轴电枢磁场;电枢磁场即为两者叠加.该方法适用于各种偏心情况下的电机磁场计算.将本模型计算的电枢磁场分布与有限元比较,结果吻合,证明其准确性和有效性.

  12. A new experimental method for the determination of the effective orifice area based on the acoustical source term

    Kadem, L.; Knapp, Y.; Pibarot, P.; Bertrand, E.; Garcia, D.; Durand, L. G.; Rieu, R.


    The effective orifice area (EOA) is the most commonly used parameter to assess the severity of aortic valve stenosis as well as the performance of valve substitutes. Particle image velocimetry (PIV) may be used for in vitro estimation of valve EOA. In the present study, we propose a new and simple method based on Howe’s developments of Lighthill’s aero-acoustic theory. This method is based on an acoustical source term (AST) to estimate the EOA from the transvalvular flow velocity measurements obtained by PIV. The EOAs measured by the AST method downstream of three sharp-edged orifices were in excellent agreement with the EOAs predicted from the potential flow theory used as the reference method in this study. Moreover, the AST method was more accurate than other conventional PIV methods based on streamlines, inflexion point or vorticity to predict the theoretical EOAs. The superiority of the AST method is likely due to the nonlinear form of the AST. There was also an excellent agreement between the EOAs measured by the AST method downstream of the three sharp-edged orifices as well as downstream of a bioprosthetic valve with those obtained by the conventional clinical method based on Doppler-echocardiographic measurements of transvalvular velocity. The results of this study suggest that this new simple PIV method provides an accurate estimation of the aortic valve flow EOA. This new method may thus be used as a reference method to estimate the EOA in experimental investigation of the performance of valve substitutes and to validate Doppler-echocardiographic measurements under various physiologic and pathologic flow conditions.

  13. Pressure drop calculation using a one-dimensional mathematical model for two-phase flow through an orifice

    Petkov, K.P.; Puton, M; Madsen, Søren Peder


    A model based on a homogeneous formulation of the governing differential equations (Navier-Stokes equations) describing the process of pressure drop in a simplified geometry of an expansion valve is investigated and simulated. Numerical solutions are compared to experimental results. The model...... is a one dimensional formulation in space and the equations incorporates the change in tubes and orifice diameter as formulated in (S. Madsen, Dynamic Modeling of Phase Crossings in Two-Phase Flow, Communications in Computational Physics 12 (4), 1129-1147). The pressure changes in the flow...

  14. Single ectopic ureteral orifice with bilateral duplicated renal collecting systems in an adult girl: Diagnosis by magnetic resonance urography.

    Tang, Min; Wang, Quanrongzi; Liu, Bianjiang; Li, Jie; Lu, Qiang; Song, Ninghong; Wang, Zengjun; Zhang, Wei


    Renal duplication accompanied by ureteral ectopia is an uncommon urinary congenital abnormality. We report the case of a 21-year-old girl who suffered from lifelong continuous urinary leakage. She was finally diagnosed with bilateral duplicated collecting systems complicated with right ectopic ureteral orifice - an extremely rare case. The patient underwent ureteric re-implantation for the ectopic side, and her urinary incontinence ceased soon thereafter. In this case, traditional imaging failed to show the exact insertion of an ectopic ureter. However, magnetic resonance urography combined with retrograde intubation radiography successfully depicted the point of ureteric insertion, which may make the diagnostic process accurate and efficient.


    王擎; 孙东红; 孙键; 骆仲泱; 岑可法; 秦裕琨


    By using a cold CFB model, the effect of horizontal orifice areas of Loop Seal with side aeration air on operational property was studied in detail.The results showed that the horizontal orifice area had a great effect on its stable operation and regulation of the recirculation rate.Under a certain range of the horizontal orifice area,the stable flow of solid particles through Loop Seal could be obtained and recirculation rate of solid particles could be well regulated and controlled through changing external aeration.The flow resistance properties across the horizontal orifice were given and an empirical equation of the pressure drop of horizontal orifice and solid circulating flow rate was proposed and a new orifice discharge coefficient was defined.The expression's were in good agreement with the experimental data.

  16. Optimal trigger position of multi-stage inductive coilgun with armature velocity%考虑电枢速度的多级感应线圈炮最佳触发位置

    向红军; 李治源; 袁建生


    针对多级感应线圈炮中,电枢的速度会影响驱动线圈的最佳触发位置,分析影响电枢受力的变量的特点,给出了电磁力的曲线.基于冲量定理,分析电枢的速度增量与电磁力及其作用时间之间的关系,得出最佳触发位置会随着电枢速度增加而不断提前的结论.为验证理论分析结果,建立感应线圈炮的仿真模型,对不同电枢初始速度下的驱动线圈最佳触发位置进行了仿真.仿真结果和分析完全一致,而且当电枢速度较高时最佳触发位置甚至会提前到电枢处于制动力的位置.通过仿真得到电枢初始速度与驱动线圈最佳触发位置之间的关系曲线,并据此给出多级感应线圈炮的触发控制策略.%The armature velocity may affect the optimal trigger position of driving coils in multistage inductive coilgun. The characteristics of variants in electromagnetic force equation was analyzed and the curve of the force was presented. Based on the impulse theorem, the relation among the velocity increment, the electromagnetic force and its time of operation were analyzed. Then an important result that as the speeding up of armature, the optimal trigger position will be brought forward was got. In order to verify the result of theory analysis, a simulation model of coilgun was built and the optimal trigger position at different initial armature velocity was studied. The simulation result is consistent with the analysis result above; furthermore, when the armature velocity is high, the optimal trigger position maybe located to the brake segment of driving coil. At last, the trigger and control strategy of multistage coilgun is given on the basis of the relationship between optimal trigger position and armature velocity got from simulation.

  17. Analysis on the influence of the armature reaction upon the doubly salient magnetic generator%电励磁双凸极发电机的电枢反应对外特性的影响分析

    陈冉; 陈志辉; 段晴晴; 毛志鑫; 龚春英


    The armature reaction of wound-field doubly salient machine ( WFDSG) is complex, and the effect reaction can both increase and decrease the magnetic field with load, causing the distortion of the flux leakage and armature current. Thus, the operating characteristics of the generator are difficult to ana lyze. This paper analyzed the relationship of the motor magnetic energy, proposed the analysis idea of the external characteristics with the relationship curves of flux linkage and armature current. With this analy sis method, the full bridge rectifier generating mode of a 12/8 pole WFDSG was discussed with the help of the finite element simulation. This research included the characteristics and discipline of the flux link age and armature current changes under different loads, and the reason why the armature reaction influ ences external characteristics. At last, the power flow was analyzed. Based on the simulation and experi ments , the correctness of the analysis method was confirmed through the magnetic energy area checking. The check result shows that the error between simulation and experiment results is less than 11% , verif ying the correctness of the analysis.%针对电励磁双凸极发电机(WFDSG)电枢反应较为复杂,带载后的电枢反应既有增磁作用又有去磁作用,导致磁链和电枢电流的波形严重畸变,不利于电机工作特性分析的情况,提出从磁能的角度分析电机工作特性的方法.根据双凸极电机的机电能量转换过程,在三相不控全桥整流发电方式(DSG2)下,针对1台12/8极电励磁双凸极发电机,分析在不同负载情况下磁链和电枢电流的变化特点和规律,从磁能的角度分析并揭示电机电枢反应作用对电机外特性的影响;分析双凸极发电机的功率流,根据仿真和实验数据进行磁能面积核算.核算结果表明,仿真和实验结果的误差在11%之内,验证了磁能分析方法的正确性.

  18. Influences of Fundamental Armature MMF on Tooth Harmonic EMF of the Rotor%基波电枢磁动势对转子齿谐波电动势的影响

    夏永洪; 龚文军; 黄劭刚; 杨玉文; 黄新


    研究电枢磁动势对转子齿谐波电动势的影响是利用电机中固有的齿谐波磁场实现永磁电机气隙磁场调节的关键问题之一。基于磁导分析法定性分析了定子基波电枢磁动势在转子侧产生齿谐波电动势的机理,讨论了线性磁路和非线性磁路下基波电枢磁动势对转子齿谐波电动势的影响。当发电机带电感性负载时,对于线性磁路,转子齿谐波电动势随着电枢电流的增加而减小;而对于非线性磁路,随着发电机电枢电流的增加,转子齿谐波电动势可能增加、不变或者减小。针对一台齿谐波励磁的混合励磁永磁同步发电机进行了计算和实验,计算结果和实验结果均与理论分析吻合。%The research on influence of the fundamental armature magnetic motive force (MMF) on the tooth harmonic electromotive force (EMF) of the rotor is one of the key problems for utilizing inherent tooth harmonic magnetic fields to achieve the adjustment of the air gap magnet field of the permanent magnet machine. The principle of the rotor tooth harmonic EMF generated by the stator fundamental armature MMF was analyzed qualitatively based on the permeability analysis method. The influence of the fundamental armature MMF on the rotor tooth harmonic EMF were discussed for linear and nonlinear magnetic circuits. When the generator is connected with an inductive load, the rotor tooth harmonic EMF decreases as the armature current increases for the linear magnetic circuits. However, for the non-linear magnetic circuits, the rotor tooth harmonic EMF may increase, maintain constant or decrease as the armature current increases. Calculation and experiment are performed for one hybrid excitation permanent magnet synchronous generator utilizing tooth harmonic for excitation, and calculated and experimental results are consistent with theoretical analysis.

  19. Cirugía endoscópica transluminal por orificios naturales: NOTES Natural orifice transluminal endoscopic surgery: NOTES

    M. J. Varas Lorenzo


    Full Text Available Se presenta una revisión actual, puesta al día, y punto de vista de los autores sobre un tema sumamente novedoso y atractivo, como es la Cirugía Endoscópica Transluminal por Orificios Naturales (NOTES: Natural Orifice Translumenal Endoscopic Surgery. La mayoría de los trabajos revisados se han realizado en animales de experimentación, pero la publicación de la colecistectomía por vía transvaginal, y la aparición de editoriales y artículos de revisión sobre el tema, nos llevan a realizar una serie de preguntas no resueltas actualmente sobre este tipo de cirugía, que representa un avance potencial para conseguir "una cirugía endoscópica sin cicatrices, sin infecciones, con mínimos requerimientos de anestesia y una inmediata recuperación".A current review and update of an exceedingly novel and appealing topic, namely natural orifice transluminal endoscopic surgery (NOTES, is discussed, as well as the authors' viewpoint thereon. Most reviewed studies were performed in laboratory animals, but reports on transvaginal cholecystectomy and the emergence of editorials and review articles on this topic pose a number of as yet unanswered questions on this type of surgery, which represents a potential advance towards "endoscopic surgery with no scars, no infection, minimal anesthesia requirements, and immediate recovery".

  20. The ergonomics of natural orifice translumenal endoscopic surgery (NOTES) navigation in terms of performance, stress, and cognitive behavior.

    James, David R C; Orihuela-Espina, Felipe; Leff, Daniel R; Sodergren, Mikael H; Athanasiou, Thanos; Darzi, Ara W; Yang, Guang-Zhong


    The evolution toward minimally invasive surgery and subsequently to natural orifice translumenal endoscopic surgery (NOTES) poses challenges to the surgeon in terms of increased task complexity requiring greater visuospatial and navigational ability. Neuroergonomics is the study of the brain and behavior at work, and establishing the baseline cortical response for NOTES procedures will help to ascertain whether technological innovation such as navigational aids can alleviate the task-induced cognitive burden. The aims of the current study are to characterize the impact of navigation within a NOTES environment on the subject in terms of (1) performance, (2) stress, (3) prefrontal cortical activity, and (4) how this is influenced by expertise. In all, 29 subjects were assessed for performance, stress response, and prefrontal cortical activity during a NOTES navigational task within a validated NOTES simulator. Experts performed significantly better than novices (P < .05). Expertise was not a predictor for overall changes in prefrontal cortical activity. The differences between experts and novices were modulated by the location of prefrontal cortical activity, with experts demonstrating more pronounced lateral prefrontal cortical activation compared with novices. Stress was not an independent predictor of changes in prefrontal cortical hemodynamics. This study is the first to characterize the performance, stress, and neurocognitive behavior associated with natural orifice translumenal endoscopic surgery navigation. The results indicate the relevance of visuospatial centers in successful task execution, and they serve as a baseline within the neuroergonomic paradigm for investigating performance-enhancing technology. Copyright © 2011 Mosby, Inc. All rights reserved.


    Varalakshmi KL


    Full Text Available Introduction: Eustachian tube is a communication between the nasopharynx and middle ear extending between the lateral wall of the nasopharynx to anterior wall of tympanic cavity.It maintains the equilibrium of air pressure on either side of the tympanic membrane for proper vibration of sound. The pharyngeal orifice of Eustachian tube is an important landmark for endoscopic surgeries and also for transnasal approach to infratemporal fossa. Materials and Methods: A total of 50 (25 right &25 leftsagittal section of head and neck specimens from adult formalin fixed cadavers from the department of anatomy, MVJ Medical college and Research Hospital, Banglore, India, were used for the study.The distance of pharyngeal orifice to posterior border of hard palate,C1 vertebra,posterior choana,tip of uvula, spehenoid sinus were measured with the digital Vernier caliper.The mean and standard deviation of these parameters were calculated. Conclusion: The knowledge of the relationship of Eustachian tube with anatomical landmarks would be useful to surgeons,otolaryngologists and radiologists.

  2. Features of localization coronary arterial orifices and angles of origin their proximal segments in usually formed hearts and with transposition of the great vessels

    Malov A.E.


    Full Text Available The work purpose was revealing of features of localization coronary arterial orifices, angles of origin and acourse of their proximal segments in usually formed hearts and with transposition of the great vessels. Research is executedon 31 specimens of usually formed hearts and 31 specimens with transposition of the great vessels. For the estimation ofposition the orifices in aortic sinuses and orientation of a course of proximal segments of coronary arteries the morphologicalresearches was carried out. For the purpose of carrying out of the statistical processing, the obtained data has been presentedon schematic images. As a result of research statistically authentic differences in localization distribution coronary arterialorifices on a vertical axis are established at a transposition of the great vessels, in comparison with usually formed hearts.Peculiarities of an arrangement orifices with acute angles of origin their proximal segments of coronary arteries and themintramural course are established.

  3. 脉冲电流波形对固体电枢滑行性能的影响%Effect of pulse current waveform on sliding performance of solid armatures

    李敏堂; 王广东; 张春和; 李会山; 张大鹏; 严萍


    By the waveform modulation with the pulse form network (PFN) of a small experimental pulsed power system, the saw-tooth waveform, convex-topped waveform and flat-topped waveform are gotten, and the three kinds of pulse, current waveforms are used for the sliding experiment of the solid armature of the electromagnetic rail driving system (EMRDS). By measuring the ultimate muzzle velocity of the experimental armature, the effects of different pulse current waveforms on the sliding performance of the solid armature are compared. The experimental results show that under low charging and discharging energy the abruptly changed saw-tooth waveform is easy to cause contact fail, and often makes the ablation phenomenon happen, so it is unfavorable to the sliding performance of solid armatures; under the same charging and discharging energy, the measured muzzle velocity under the convex-topped waveform pulse is higher than that under the flat-topped one, which means the efficiency of the former is higher than that of the latter; the flat-topped waveform can bear higher charging and discharging energy than the convex-topped one, and its ultimate muzzle velocity is also higher; among the three kinds of waveforms, the flat-topped waveform is the most propitious to the sliding performance of solid armatures because it can provide good contact of the solid armature and rail.%利用一种小型脉冲功率系统的脉冲形成网络进行波形调制,得到了锯齿、凸顶和平顶脉冲电流波形,利用这三种脉冲电流开展了导轨型电磁驱动系统中的固体电枢滑行实验,通过测量电枢极限出口速度,比较了不同脉冲电流波形对固体电枢滑行性能的影响.结果表明:电流变化急剧的锯齿波形在较低的充放电能量下就会引起固体电枢与导轨界面接触失效,发生烧蚀现象,因而不利于固体电枢的滑行;相同充放电能量条件下,凸顶波形比平顶波形得到的固体电枢出口测速高,即

  4. Armature reaction demagnetization analysis for line-start permanent magnet synchronous motor during start process%自起动永磁同步电机起动过程电枢反应退磁分析

    卢伟甫; 罗应立; 赵海森


    为了研究自起动永磁同步电机起动过程中电枢反应引起的永磁体退磁,采用场-路-运动耦合的时步有限元法,分析了自起动永磁同步电机起动过程中,电枢同步旋转磁场和转子永磁磁场的相对空间位置角δ与电枢电流幅值对永磁体工作点磁密的影响,得到了不同负载条件下的电枢反应退磁特点.结果表明:当相对位置角δ=π时,电枢磁场对永磁磁场的去磁作用较大,永磁体平均工作点磁密较低,且负载系数越大,永磁体经历δ=π时刻的次数越多,永磁体磁密多次出现较低点,永磁体退磁几率变大;起动过程中随着转速升高,电枢电流幅值减小,在接近同步速的δ=π时刻,永磁体磁密出现最低点,电枢反应退磁较严重.%To research the demagnetization of permanent magnet caused by the armature reaction during the start process of line-start permanent magnet synchronous motor ( LSPMSM ) , the field-circuit-motion coupled time-stepping finite element method was adopted to analyze the influence of 5 and the current amplitude on the permanent magnet working point flux density during the start process of LSPMSM, where 5 was the relative space position angle between the rotor permanent magnetic field and the armature synchronous rotating magnetic field. The armature reaction demagnetization characteristics under different load conditions were gained. Results show that at the moment of δ = π, the demagnetization effect of the armature magnetic field on the permanent magnetic field is significant, and the average working point flux density of permanent magnet is low. However, the permanent magnet suffers more moments of δ = π during the start with heavier load, and the lower permanent magnet flux density appears more times, which make the magnet demagnetization more liable. Moreover, the armature current amplitude decreases with speed rising, and the permanent magnet flux density reaches the lowest point at the

  5. 旋转整流式无刷交、直流发电机谐波电枢反应构建%Rotating Rectifier Type Brushless AC and DC Generator Building Harmonic Armature Reaction



    同步发电机带整流负载后,三相电枢绕组电流将出现谐波分量,其大小、成分与负载状况和整流器的型式子相关。相对其他电枢反应来说,构建旋转整流器式无刷交、直流发电机谐波电枢反应,能够在客观上提升发电质量,进一步满足电力运行需求。为了保证电力方面的工作能够更好地被执行,让电力需求得到较好的供应,需要在构建过程中注意相关因素的影响。%After the synchronous generator with rectifier load, three-phase armature winding current harmonics will occur, the size, composition and load conditions associated with the sub-type rectifier. Compared to other armature reaction, the construction of the rotary Brushless AC and DC generator harmonic armature reaction, can improve power quality in the objective to further meet the needs of electricity to run. In order to ensure better working electricity can be executed, so that the power supply needs to get better, you need to pay attention to the relevant factors in the build process.

  6. Structural Optimization for C-shaped Armature in Rail Gun Based on Response Surface Method%基于响应面法的轨道炮C型电枢结构优化设计

    彭晓婷; 马瑞; 李刚; 战再吉


    The structural parameters of the C-shaped solid armature affect directly the emission of electromagnetic rail gun.Aiming at this problem,a structural optimization method for the C-shaped armature was proposed based on numerical analysis.The proposed method employs the orthogonal experiment to design sample data,and the optimization function was constructed based on response surface method.The genetic algorithm was used to get the minimum.The minimum value of the maximum current density was obtained.The simulation experiments show that the method reduces the peak current density and the possibility of transition in higher accuracy and feasibility.It provides an effective way to improve the armature structure.%C型结构固体电枢结构参数直接影响到电磁轨道炮的发射,针对此问题,提出了一种基于数值分析的 C型电枢机构优化方法,该方法采用正交试验设计样本数据,基于响应面法构造优化函数,采用遗传算法进行极小值优化,获得了最大电流密度值的极小值。数值模拟实验表明:该方法降低了电流密度峰值,降低了转捩发生的可能性,具有较高的准确性和可行性,能够为电枢结构改进提供有效途径。

  7. Objective performance measures using motion sensors on an endoscopic tool for evaluating skills in natural orifice translumenal endoscopic surgery (NOTES).

    Chin, Lauren I; Sankaranarayanan, Ganesh; Dargar, Saurabh; Matthes, Kai; De, Suvranu


    Natural orifice translumenal endoscopic surgery is an emerging procedure. High fidelity virtual reality-based simulators allow development of new surgical procedures and tools and train medical personnel without risk to human patients. As part of a project funded by the National Institutes of Health, we are developing a Virtual Transluminal Endoscopic Surgery Trainer (VTEST TM) for this purpose. In this work, objective performance measures derived from motion tracking sensors attached to an endoscope was tested for the transgastric NOTES appendectomy procedure performed with ex-vivo pig organs using the EASIE-R(TM) trainer box. Results from our study shows that both completion time and economy of motion parameters were able to differentiate between expert and novice NOTES surgeons with p value of 0.039 and 0.02 respectively. Jerk computed on sensor 2 data also showed significant results (p = 0.02). We plan to incorporate these objective performance measures in VTEST(TM).


    ZHOU Hua


    Axisymmetric liquid jets have been studied extensively for more than one century, while non-axisymmetric jets are also very common in engineering applications but attract less concern. Based on Eulerian fluid-fluid model in Fluent software, this article analysizes the 3-D flow fields of pressure atomizers with V-shaped cut at orifice, which will result in a non-axisymmetric liquid jet.Flow rate analysis and jet structure analysis are carried out, the results show that the flow rate can be formulated by adding a correction coefficient to the formula of inviscid axisymmetric jets in atomization regime, when the Weber number is low enough to make the flow fall out of atomization regime, and the jet structure together with the flow rate formula will change. Analysis shows that the evolution of the spray and therefore the structure of the liquid jet are affected much by relative velocity and the local volume fraction of liquid phase.

  9. Current status of natural orifice trans-endoscopic surgery (NOTES and laparoendoscopic single site surgery (LESS in urologic surgery

    Rafael E. Sanchez-Salas


    Full Text Available Laparoendoscopic single site surgery (LESS and natural orifice transluminal endoscopic surgery (NOTES represent novel approaches in urological surgery. To perform a review of the literature in order describe the current status of LESS and NOTES in Urology. References for this manuscript were obtained by performing a review of the available literature in PubMed from 01-01-02 to 15-05-09. Search terms included single port, single site, NOTES, LESS and single incision. A total of 412 manuscripts were initially identified. Out of these, 64 manuscripts were selected based in their urological content. The manuscript features subheadings for experimental and clinical studies, as NOTES-LESS is a new surgical technique and its future evolution will probably rely in initial verified feasibility. A subheading for reviews presents information regarding common language and consensus for the techniques. The issue of complications published in clinical series and the future needs of NOTES-LESS, are also presented.

  10. Three-dimensional echocardiographic planimetry of maximal regurgitant orifice area in myxomatous mitral regurgitation: intraoperative comparison with proximal flow convergence

    Breburda, C. S.; Griffin, B. P.; Pu, M.; Rodriguez, L.; Cosgrove, D. M. 3rd; Thomas, J. D.


    OBJECTIVES: We sought to validate direct planimetry of mitral regurgitant orifice area from three-dimensional echocardiographic reconstructions. BACKGROUND: Regurgitant orifice area (ROA) is an important measure of the severity of mitral regurgitation (MR) that up to now has been calculated from hemodynamic data rather than measured directly. We hypothesized that improved spatial resolution of the mitral valve (MV) with three-dimensional (3D) echo might allow accurate planimetry of ROA. METHODS: We reconstructed the MV using 3D echo with 3 degrees rotational acquisitions (TomTec) using a transesophageal (TEE) multiplane probe in 15 patients undergoing MV repair (age 59 +/- 11 years). One observer reconstructed the prolapsing mitral leaflet in a left atrial plane parallel to the ROA and planimetered the two-dimensional (2D) projection of the maximal ROA. A second observer, blinded to the results of the first, calculated maximal ROA using the proximal convergence method defined as maximal flow rate (2pi(r2)va, where r is the radius of a color alias contour with velocity va) divided by regurgitant peak velocity (obtained by continuous wave [CW] Doppler) and corrected as necessary for proximal flow constraint. RESULTS: Maximal ROA was 0.79 +/- 0.39 (mean +/- SD) cm2 by 3D and 0.86 +/- 0.42 cm2 by proximal convergence (p = NS). Maximal ROA by 3D echo (y) was highly correlated with the corresponding flow measurement (x) (y = 0.87x + 0.03, r = 0.95, p < 0.001) with close agreement seen (AROA (y - x) = 0.07 +/- 0.12 cm2). CONCLUSIONS: 3D echo imaging of the MV allows direct visualization and planimetry of the ROA in patients with severe MR with good agreement to flow-based proximal convergence measurements.

  11. Planimetric Measurement of the Regurgitant Orifice Area Using Multidetector CT for Aortic Regurgitation: a Comparison with the Use of Echocardiography

    Jeon, Min Hee; Choe, Yeon Hyeon; Cho, Soo Jin; Park, Seung Woo; Park, Pyo Won; Oh, Jae K. [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)


    This study compared the area of the regurgitant orifice, as measured by the use of multidetector-row CT (MDCT), with the severity of aortic regurgitation (AR) as determined by the use of echocardiography for AR. In this study, 45 AR patients underwent electrocardiography- gated 40-slice or 64-slice MDCT and transthoracic or transesophageal echocardiography. We reconstructed CT data sets during mid-systolic to enddiastolic phases in 10% steps (20% and 35-95% of the R-R interval), planimetrically measuring the abnormally opened aortic valve area during diastole on CT reformatted images and comparing the area of the aortic regurgitant orifice (ARO) so measured with the severity of AR, as determined by echocardiography. In the 14 patients found to have mild AR, the ARO area was 0.18{+-} 0.13 cm{sup 2} (range, 0.04-0.54 cm{sup 2}). In the 15 moderate AR patients, the ARO area was 0.36 {+-} 0.23 cm{sup 2} (range, 0.09-0.81 cm{sup 2}). In the 16 severe AR patients, the ARO area was 1.00 {+-} 0.51 cm{sup 2} (range, 0.23-1.84 cm{sup 2}). Receiver-operator characteristic curve analysis determined a sensitivity of 85% and a specificity of 82%, for a cutoff of 0.47 cm{sup 2}, to distinguish severe AR from less than severe AR with the use of CT (area under the curve = 0.91; 95% confidence interval, 0.84-1.00; p < 0.001). Planimetric measurement of the ARO area using MDCT is useful for the quantitative evaluation of the severity of aortic regurgitation.

  12. The measurement of opening angle and orifice area of a bileaflet mechanical valve using multidetector computed tomography.

    Lee, Dong-Hyeon; Youn, Ho-Joong; Shim, Sung-Bo; Lee, Sun-Hee; Jung, Jung-Im; Jung, Seung-Eun; Choi, Yun-Seok; Park, Chul-Soo; Oh, Yong-Seog; Chung, Wook-Sung; Kim, Jae-Hyung


    The aim of this study was to assess mechanical valve function using 64-slice multidetector computed tomography (MDCT). In 20 patients (mean age, 50+/-12 years; male-to-female ratio, 10:10), 30 St. Jude bileaflet mechanical valves (15 aortic and 15 mitral valves) were evaluated using MDCT. We selected images vertical and parallel to the mechanical valve. The valve orifice area (OA) and valve length were determined by manual tracing and the opening and closing angles were measured using a protractor. The OA and length of the mechanical valves were compared with the manufacturer's values. The geometric orifice areas (GOAs) based on the manufacturer's values and the OAs determined by MDCT were 3.4+/-0.2 cm(2) and 3.4+/-0.3 cm(2) for the mitral valves and 2.1+/-0.3 cm(2) and 2.1+/-0.4 cm(2) for the aortic valves, respectively. The correlation coefficients between the OA measures were 0.433 for the mitral valves and 0.874 for the aortic valves (both pvalves and 21.5+/-2.1 mm and 20.7+/-2.3 mm for the aortic valves, respectively. The correlation coefficients between the measures were 0.651 for the mitral valve and 0.846 for the aortic valve (both pvalves and 11.1+/-0.9 degrees and 120.6+/-1.7 degrees for the aortic valves, respectively. MDCT is an accurate modality with which to assess the function and morphology of bileaflet mechanical valves.

  13. Combined Engraving Process of C-Shaped Solid Armature in Electromagnetic Railgun%电磁轨道炮C型固体电枢坡膛段的装填方式研究

    张祎; 杨春霞; 栗保明


    为了满足电磁轨道炮对电枢和轨道间初始接触压力的要求,以小口径电磁轨道炮C型固体电枢的坡膛段装填过程为研究对象,在力学分析的基础上,采用有限元计算方法,对匀速装填、冲击装填以及组合装填3种方式进行了计算,并对电枢臂头部、中间和尾端单元的径向变形、应力和剪切应力随时间的变化进行了对比分析。分析结果表明,在同等条件下,采用组合装填方式可以明显地降低固体电枢在装填过程中受剪切破坏的程度,并有效地提高初始接触压力。研究结果表明,组合装填方式有利于提高电磁轨道炮的发射效率。%In order to meet the requirement for initial contact pressure between armature and rails of electromagnetic railgun, by taking the engraving process of C-shaped armature in small caliber electromagnetic railgun as the research object, three engraving modes including uniform loading,impact loading and combined loading are simulated by using finite element method based on the mechanical analysis,and then the changes of radial deformation,stress and shear stress of the elements in the armature arm are compared and analyzed. The results show that the combined loading can obviously decrease the degree of shearing damage during solid armature engraving process and, in addition, improve initial contact pressure effectively in the same condition. The research findings show that combined mode is beneficial to increase the launching efficiency of electromagnetic railgun.

  14. Running Characteristics Analysis of Electromagnetic Coil Launcher With Current-carrying Armature%载流电枢电磁线圈发射器运行特性分析

    金洪波; 曹延杰; 王成学; 王慧锦


    The armature is the key part for energy exchange in electromagnetic coil launcher (EMCL).The structural model with series-current armature launcher ( SCCAL ) and parallel-current armature launcher ( PCCAL) was proposed .System differential equation was deduced by analyzing the working principle and the structure character of two kinds of current-carrying armature launcher ( CCAL) .Systematical model of the CCAL was built with MATLAB , and the launching character was analyzed .The analysis shows that there is no pulling effect in launching process in CCAL .SCCAL is more suitable for accelerating payload with low-velocity less than 20 m/s by using low-voltage-capacitor power-supply .PCCAL can be used to accelerating payload with high velocity more over 50 m/s by using high-voltage-capacitor power-supply . The conclusion has great significance for guiding the structural design in EMCL .%电枢是电磁线圈发射器能量转换的关键部分,以此为研究对象,提出串联载流电枢发射器和并联载流电枢发射器的结构模型,通过分析2种载流电枢发射器的工作原理和结构特点,得到了系统微分方程,并利用MATLAB建立了载流电枢发射器的系统仿真模型,分析了发射器的运行特性。分析结果表明,载流电枢发射器发射过程无拖拽效应,串联载流电枢发射器适于载荷在20 m/s以下的加速段使用,适于选用低压的电容器电源;并联载流电枢发射器可用于载荷在50 m/s以上的加速段使用,适于选用高电压电容器。研究结果对电磁线圈发射器电枢结构设计具有一定的指导意义。

  15. 轨道与电枢间运动电磁场分布的数值计算%Numerical Calculation of Movement Electromagnetic Field Distribution Between Rail and Armature

    杨玉东; 付成芳; 薛文; 赵环宇


    To research the situation of current density distribution between the rail and the ar-mature during the process of electromagnetic emission,the relationships between the electro-magnetic parameters and armature moving velocity were derived by use of Maxwell electromag-netic theory.The convection diffusion equations for electromagnetic field in Cartesian coordi-nate system were set up.The convection and diffusion terms in convection diffusion equation were decomposed by means of the operator splitting scheme,and the parabolic and hyperbolic equations were all solved by use of the finite difference method.Calculations showed that the operator splitting scheme can effectively solve the electromagnetic convection-diffusion equa-tion,and this method is stable and convergent.The calculation results with the examples showed that when the armature moves at high velocity,the current density between the local area of armature and the rail is the maximum and it is easy to give rise to the erosion in local re-al rail material.%为探讨电磁发射过程中轨道和电枢间电流分布情况,根据 Maxwell 方程推导出电磁场参数与速度之间的关系,建立了直角坐标系下的电磁场对流扩散方程,采用算子分裂格式对对流扩散方程中对流项和扩散项进行分解,分别对抛物型和双曲型方程采用有限差分法进行求解。计算过程表明算子分裂格式能有效求解电磁场对流扩散方程,算法稳定,收敛性好。结合实例的计算结果显示,当电枢高速运动时,在轨道和电枢局部区域的电流密度极大,容易造成轨道材料的烧蚀。

  16. 基于B探针的轨道炮电枢位置测量及研究%Measurement and Study of Electromagnetic Rail Gun Armature Position Based on B-dot Probe

    李菊香; 苏子舟; 国伟; 曹斌; 杨永亮


    以往都是用B探针感应电压信号的过零点时间作为电枢通过 B探针的时间,但此方法存在一定的误差。为了测量电磁轨道炮发射过程中电枢在膛内运动时准确位置,通过理论分析和推导得出 B探针的感应电压是由脉冲电流及电枢运动共同作用产生的,并推导出由B探针感应电压及脉冲电流计算电枢通过 B探针准确时刻的方法。根据电磁感应原理设计了B探针,并在试验中运用新方法计算出电枢通过B探针的时刻,与B探针感应电压信号的过零点时间做比较,根据拟合的速度曲线,得出使用输出信号过零点作为电枢通过B探针时间存在一定的位置误差值,使用新方法可以提高测量精度。%Previously,the zero crossing time of the induced voltage signal (ZCTV)was used to measure the time when armatures passing through the B-dot probe (APTB),but this method had a certain error value.To measure the accurate position of solid armature during the launching process of the electromag-netic rail gun,its induction voltage generated by the pulse current through the armature and the armature movement were analyzed by use of the theoretical analysis and derivation,and a new method about calcu-lating APTB from the sensed voltage and the pulsed current of B-dot probe was presented.The B-dot probe was designed according to the principle of electromagnetic induction.In experiment,the new method was applied to calculate APTB and this calculated time was compared with ZCTV.The results showed that the position error does exist when ZCTV was used as APTB according to the fitted velocity curve,and the new method can improve the accuracy of measurement.

  17. Exergy analysis of a counter flow Ranque-Hilsch vortex tube for different cold orifice diameters, L/D ratios and exit valve angles

    Devade, Kiran D.; Pise, Ashok T.


    An experimental investigation is made to find out the effects of the cold end orifice diameters, length to diameter ratio and exit valve angles on the heating and cooling performance of the counter flow Ranque-Hilsch vortex tube with air as a working fluid. The tube and cold end orifices used at these experiments are made of brass. Three cold end orifices (5, 6 and 7 mm) have been manufactured and are used five different L/D ratios (15 plain tube, 15-18 with 4° divergence angle) and exit valve angles (30°-90°). Inlet pressures were adjusted from 200 to 600 kPa with 100 kPa increments, and the exergy loss, exergy efficiency was determined. As a result of the experimental study, it is determined that the exergy loss between the hot and cold fluid is decreased with increasing of the cold end orifice diameter. Exergy efficiency decreases with increase in L/D ratio. It is also concluded that diverging vortex tube produces lower exergy loss as compared to plain tube. Valve angles have significant effect on hot end exergy loss of the vortex tube.

  18. Placement of Endovascular Stent across the Branching Arteries: Long-term Serial Evaluation of Stent-tissue Responses Overlying the Arterial Orifices in an Experimental Study

    Kim, Young Il; Chung, Jin Wook, E-mail: [Seoul National University College of Medicine, Department of Radiology (Korea, Republic of); Kim, Hyun Beom [National Cancer Center of Korea, Department of Radiology and Center for Liver Cancer, Research Institute and Hospital (Korea, Republic of); Park, Jae Hyung [Seoul National University College of Medicine, Department of Radiology (Korea, Republic of); Seo, Jeong Wook [Seoul National University College of Medicine, Department of Pathology (Korea, Republic of); Kim, Hyo-Cheol; Jae, Hwan Jun; Lee, Whal [Seoul National University College of Medicine, Department of Radiology (Korea, Republic of)


    PurposeThis study was designed to investigate the effects of stenting across the branching arteries on the patency and stent-tissue responses over the branching arterial orifices. Methods: Thirteen dogs were observed after placing aortic stents across the celiac arteries (CA), superior mesenteric arteries (SMA), and renal arteries (RA). The animals were grouped according to stent types: large-cell group (n = 6) and small-cell group (n = 7). Angiography was performed to evaluate the branching artery patency at 2, 6, and 12 months after stent insertion, and the stent-tissue responses covering the orifices were evaluated on histopathologic examination. Results: All branching arteries were patent on follow-up angiography; however, three patterns of stent-tissue responses over the orifices were observed: neointimal layering, bridging septa, and papillary hyperplasia. Although neointimal layering and bridging septa were evenly observed, severe papillary hyperplasia was more frequent at SMA and CA than RA. Four RA showed less than 50% ostial patency, and localized infarct was observed in six kidneys (24%). The ostial patency tended to decrease with small-cell stent during the follow-up period. Conclusions: Various stent-tissue responses over the branching artery orifices are induced by the aortic stent covering the branching arteries and may not be easily detected by conventional angiography. Subclinical renal infarct also may occur despite patent renal angiography.

  19. Calcification at orifices of aortic arch branches is a reliable and significant marker of stenosis at carotid bifurcation and intracranial arteries

    Yamada, Shigeki, E-mail: [Department of Neurosurgery and Stroke Center, Rakuwakai Otowa Hospital, Kyoto (Japan); Interfaculty Initiative in Information Studies/Institute of Industrial Science, The University of Tokyo, Tokyo (Japan); Department of Neurosurgery, Hamamatsu Rosai Hospital, Shizuoka (Japan); Hashimoto, Kenji, E-mail: [Department of Neurosurgery, Kishiwada Municipal Hospital, Osaka (Japan); Ogata, Hideki, E-mail: [Department of Neurosurgery, Hamamatsu Rosai Hospital, Shizuoka (Japan); Watanabe, Yoshihiko, E-mail: [Department of Neurosurgery, Hamamatsu Rosai Hospital, Shizuoka (Japan); Oshima, Marie, E-mail: [Interfaculty Initiative in Information Studies/Institute of Industrial Science, The University of Tokyo, Tokyo (Japan); Miyake, Hidenori, E-mail: [Department of Neurosurgery, Hamamatsu Rosai Hospital, Shizuoka (Japan)


    Purpose: Simple rating scale for calcification in the cervical arteries and the aortic arch on multi-detector computed tomography angiography (MDCTA) was evaluated its reliability and validity. Additionally, we investigated where is the most representative location for evaluating the calcification risk of carotid bifurcation stenosis and atherosclerotic infarction in the overall cervical arteries covering from the aortic arch to the carotid bifurcation. Method: The aortic arch and cervical arteries among 518 patients (292 men, 226 women) were evaluated the extent of calcification using a 4-point grading scale for MDCTA. Reliability, validity and the concomitant risk with vascular stenosis and atherosclerotic infarction were assessed. Results: Calcification was most frequently observed in the aortic arch itself, the orifices from the aortic arch, and the carotid bifurcation. Compared with the bilateral carotid bifurcations, the aortic arch itself had a stronger inter-observer agreement for the calcification score (Fleiss’ kappa coefficients; 0.77), but weaker associations with stenosis and atherosclerotic infarction. Calcification at the orifices of the aortic arch branches had a stronger inter-observer agreement (0.74) and enough associations with carotid bifurcation stenosis and intracranial stenosis. In addition, the extensive calcification at the orifices from the aortic arch was significantly associated with atherosclerotic infarction, similar to the calcification at the bilateral carotid bifurcations. Conclusions: The orifices of the aortic arch branches were the novel representative location of the aortic arch and overall cervical arteries for evaluating the calcification extent. Thus, calcification at the aortic arch should be evaluated with focus on the orifices of 3 main branches.

  20. Calculation of Air-Gap Magnetic Fields and Armature Reaction Reactances of Claw-Pole Alternator%爪极发电机气隙磁场与电枢反应电抗的计算

    匡秀洪; 庄圣贤; 熊冬情


    采用三维有限元方法对一台爪极发电机的电枢反应进行了研究.基于ANSOFT软件对电机气隙磁场和电感矩阵进行了计算仿真,通过对电感矩阵进行派克变换,进而得到交、直轴的电枢反应电抗.所得结果与用相量图方法计算的结果进行了比较,证明了解的正确性与可行性,为爪极发电机的优化设计奠定了理论基础.%The armature reaction of a claw-pole alternator using three dimensional finite element method was analyzed. Air-gap magnetic fields and inductance matrix were calculated by Ansoft. The quadrature-axis and direct-axis armature reaction reactance were obtained through the Park transformation. The results between this method and phasor diagram method were compared and verified. Its validity and feasibility were indicated, which was the theoretic foundation for the optimum design of claw-pole alternators.

  1. Effect of armature material and projectile pullback weight to ship-borne coilgun efficiency%电枢材料和弹丸配重对舰载线圈炮效率的影响

    陈学慧; 曹延杰; 王成学; 王慧锦


    针对工程中常用的电枢材料,通过改变弹丸配重,寻找各配重情况下电枢的最佳初始位置,应用数值仿真对舰载线圈炮的能量转换效率进行研究,得到电枢材料和弹丸配重对能量转换效率的影响规律.结果表明,对于一个特定的舰载线圈炮系统,存在一个最佳的弹丸配重使有效载荷的能量转换效率达到最大,为舰载线圈炮的电枢和弹丸设计提供参考.%Take projectile pullback weight as variable,the energy conversion efficiency of ship-borne coilgun is analyzed applying numerical simulation through searching the respective optimal initial location to materials which is common used in engineering.The research result indicates that there existed an optimal pullback weight for a definite ship-borne coilgun system ; the law of the effect on projectile pullback weight to projectile and payload efficiency is obtained through optimize the respective armature initial location,which provides the theoretical reference for design of the armature and projectile.

  2. Experiment on Performance of Air Supply Orifice in Rail Vehicle%轨道车辆孔板送风特性的试验研究

    臧建彬; 王亚伟; 陈佳; 高乃平; 史意


    Air distribution inside rail vehicles directly affects comfort of passengers. Air supply orificeds in static pressure boxes are characterize by simple structure,well-distributed air temperatures and velocities,so they are suitable for the place of strict requirements for space temperature spans and wind speeds. But the limited space of rail vehicles imposes restrictions on the plenum space of the static pressure boxes,which easily causes nonu-niform static pressures in the static pressure boxes and hinders uniform distribution of orifice air supply;since there are certain sealting areas on both sides of the roof, uniformity of distribution of orifice air supply is affected to some extent in the direction of the width. In this paper,the 1: 1 scale model tests were made. The kind of orifices used in the maglev train was chosen for the tests. The orifice air supply law was studied under the isothermal conditions. The resistance characteristics, static pressure distribution above the orifice and orifice air supply distribution uniformity were investigated.%轨道车辆客室内的气流组织直接影响乘客乘坐的舒适性.静压箱孔板送风具有结构简单、送风温度和速度均匀等优点,适用于区域温差和工作区风速要求严格的场所.但是由于轨道车辆空间有限,静压箱稳压层的高度受限,容易造成静压箱内静压不均匀,影响孔板送风的均匀性;而顶棚两侧由于存在一定的密封区域,对宽度方向上的送风均匀性也有一定的影响.本文采用1:1等比例模型试验的方法,针对一种运用在磁悬浮列车上的孔板,在等温条件下,对轨道车辆孔板送风规律进行研究,考察其阻力特性、孔板上方静压分布及孔板送风均匀性.

  3. 小孔径多级孔板组件节流效应仿真%Simulation for throttling effect of small aperture multistage orifice units

    刘万龙; 梁国柱; 徐铭; 张化照


    对小孔径多级孔板组件(简称多级孔板)节流效应进行仿真研究,发现这类仿真对初场要求非常严格,初场不合理很容易产生伪平衡问题,通过迭代计算寻找合理初场的方法解决了该问题.同时对孔径0.1 mm、孔径比0.025的多级孔板进行了数值仿真,仿真结果表明孔板数是影响多级孔板流量系数的主要因素.根据仿真数据给出多级孔板流量系数拟合公式,可以应用于工程设计计算.%Throttling effect of small aperture multistage orifice units was studied through simulation method. It was found that strict initial flow field was needed in this kind of simulation, and the simulation would be dummy-balanced with irrational initial flow field. This problem was solved by iterative finding proper initial flow field. The multistage orifice units with 0.1 mm aperture and 0.025 aperture ratio were simulated. The simulation result shows that the number of the orifices is the major factor which influences the flow coefficients of the multistage orifice units. Fitted formulae for the flow coefficients were given depending on the simulation results. The fitted formulae can be applied to actual engineering design calculation.

  4. Combined experimental and computational investigation of the cavitating flow in an orifice plate with special emphasis on surrogate-based optimization method

    Li, XianLin; Huang, Biao; Chen, Tairan; Liu, Ying; Qiu, Si Cong [School of Mechanical and Vehicular Engineering, Beijing Institute of Technology, Beijing (China); Zhao, Jing [China Academy of Launch Vehicle Technology, Beijing (China)


    We investigated the influence of geometrical parameters of the orifice plate on the cavitation structures, and optimized these parameters by using a surrogate-based model with special emphasis on the concentration of hydroxyl radical released. The results show that for the orifice plate of the hydrodynamic cavitation system, the possible location of the inception of the cavity spreads to throat and divergent section of the venturi geometry. Based on the surrogate model and global sensitivity assessment, the diameter of throat Dt and diameter of inlet Din significantly influenced the size of the cavity, while the length of throat Lt had little effect on both cavitation intensity and flow rate. It should be noted that when Lt is decreased, the size of cavity would be slightly decreased but the flow rate increased clearly. The increase of the diverging section is in favor of the size of cavity. By comparing the experimental measurements on the concentration of Methylene blue, the optimum geometry of the orifice plate for best cavitational activity is proposed.

  5. Characterization of Gatewell Orifice Lighting at the Bonneville Dam Second Powerhouse and Compendium of Research on Light Guidance with Juvenile Salmonids

    Mueller, Robert P.; Simmons, Mary Ann


    The goal of the study described in this report is to provide U.S. Army Corps of Engineers (USACE) biologists and engineers with general design guidelines for using artificial lighting to enhance the passage of juvenile salmonids into the collection channel at the Bonneville Dam second powerhouse (B2). During fall 2007, Pacific Northwest National Laboratory (PNNL) researchers measured light levels in the field at one powerhouse orifice through which fish must pass to reach the collection channel. Two light types were evaluated—light-emitting diode (LED) lights and halogen spot lights. Additional measurements with mercury lamps were made at the PNNL Aquatic Research Laboratory to determine baseline intensity of the current lighting. A separate chapter synthesizes the relevant literature related to light and fish guidance for both field and laboratory studies. PNNL will also review the Corps plans for existing lighting protocol at all of the Portland District projects and help develop a uniform lighting scheme which could be implemented. The specific objectives for this study are to 1. Create a synthesis report of existing lighting data for juvenile salmonid attraction and deterrence and how the data are used at fish bypass facilities. 2. Evaluate current B2 orifice lighting conditions with both LED and halogen sources. 3. Make recommendations as to what lighting intensity, source, and configuration would improve passage at the B2 orifices. 4. Review USACE plans for retrofit of existing systems (to be assessed at a later date).

  6. Caractérisation électrochimique des armatures dans les bétons : Etude du transfert de charges électriques dans différents ciments



    L'objectif de ce stage constitue une formation en électrochimie appliquée aux bétons armés. Il s'agit de se familiariser avec les mesures électrochimiques afin de rendre compte de l'état de passivation ou de corrosion des armatures du béton. Par la suite, cette compétence en électrochimie sera utilisée pour mieux appréhender l'efficacité des traitement électrochimiques (de déchloruration et de ré-alcalinisation par exemple) récemment proposés pour la réparation des ouvrages d'art en béton arm...

  7. Planimetry of the aortic valve orifice area: Comparison of multislice spiral computed tomography and magnetic resonance imaging

    Westermann, Yvonne; Geigenmueller, Anja; Elgeti, Thomas; Wagner, Moritz [Department of Radiology, Charite - University Medicine, Berlin (Germany); Dushe, Simon [Department of Cardiovascular Surgery, Charite - University Medicine, Berlin (Germany); Borges, Adrian C. [Department of Internal Medicine I - Cardiology, Angiology and Pneumology, Charite - University Medicine, Berlin (Germany); Dohmen, Pascal M. [Department of Cardiovascular Surgery, Charite - University Medicine, Berlin (Germany); Hein, Patrick A. [Department of Radiology, Charite - University Medicine, Berlin (Germany); Lembcke, Alexander, E-mail: [Department of Radiology, Charite - University Medicine, Berlin (Germany)


    Objective: We sought to determine the comparability of multislice computed tomography (MSCT) and magnetic resonance imaging (MRI) for measuring the aortic valve orifice area (AVA) and grading aortic valve stenosis. Materials and methods: Twenty-seven individuals, among them 18 patients with valvular stenosis, underwent AVA planimetry by both MSCT and MRI. In the subset of patients with valvular stenosis, AVA was also calculated from transthoracic Doppler echocardiography (TTE) using the continuity equation. Results: There was excellent correlation between MSCT and MRI (r = 0.99) and limits of agreement were in an acceptable range ({+-}0.42 cm{sup 2}) although MSCT yielded a slightly smaller mean AVA than MRI (1.57 {+-} 0.83 cm{sup 2} vs. 1.67 {+-} 0.98 cm{sup 2}, p < 0.05). However, in the subset of patients with valvular stenosis, the mean AVA was not different between MSCT and MRI (1.05 {+-} 0.30 cm{sup 2} vs. 1.04 {+-} 0.39 cm{sup 2}; p > 0.05). The mean AVAs on both MSCT and MRI were systematically larger than on TTE (0.88 {+-} 0.28 cm{sup 2}, p < 0.001 each). Using an AVA of 1.0 cm{sup 2} on TTE as reference, the best threshold for detecting severe-to-critical stenosis on MSCT and MRI was an AVA of 1.25 cm{sup 2} and 1.30 cm{sup 2}, respectively, resulting in an accuracy of 96% each. Conclusion: Our study specifies recent reports on the suitability of MSCT for quantifying AVA. The data presented here suggest that certain methodical discrepancies of AVA measurements exist between MSCT, MRI and TTE. However, MSCT and MRI have shown excellent correlation in AVA planimetry and similar accuracy in grading aortic valve stenosis.

  8. Endoscopic multiple metal stenting for the treatment of enteral leaks near the biliary orifice: A novel effective rescue procedure

    Massimiliano Mutignani; Lorenzo Dioscoridi; Stefanos Dokas; Paolo Aseni; Pietro Carnevali; Edoardo Forti; Raffaele Manta; Mariano Sica; Alberto Tringali; Francesco Pugliese


    Between April 2013 and October 2015, 6 patients developed periampul ary duodenal or jejunal/biliary leaks after major abdominal surgery. In all patients, percutaneous drainage of the collection or re-operation with primary surgical repair was attempted at first but failed. A fully covered enteral metal stent was placed in all patients to seal the leak. Subsequently, we cannulated the common bile duct and, in some cases, and the main pancreatic duct inserting hydrophilic guidewires through the stent after dilating the stent mesh with a dilatation balloon or breaking the meshes with Argon Plasma Beam. Finally, we inserted a fully covered biliary metal stent to drain the bile into the lumen of the enteral stent. In cases of normal proximal upper gastrointestinal anatomy, a pancreatic plastic stent was also inserted. Oral food intake was initiated when the abdominal drain outflow stopped completely. Stent removal was scheduled four to eight weeks later after a CT scan to confirm the complete healing of the fistula and the absence of any perilesional residual fluid collection. The leak resolved in five patients. One patient died two days after the procedure due to severe, pre-existing, sepsis. The stents were removed endoscopically in four weeks in four patients. In one patient we experiencedstent migration causing small bowel obstruction. In this case, the stents were removed surgically. Four patients are still alive today. They are still under follow-up and doing well. Bilio-enteral fully covered metal stenting with or without pancreatic stenting was feasible, safe and effective in treating postoperative enteral leaks near the biliopancreatic orifice in our small series. This minimally invasive procedure can be implemented in selected patients as a rescue procedure to repair these challenging leaks.

  9. Laparoscopic resection with natural orifice specimen extraction versus conventional laparoscopy for colorectal disease: a meta-analysis.

    Ma, Bin; Huang, Xuan-Zhang; Gao, Peng; Zhao, Jun-Hua; Song, Yong-Xi; Sun, Jing-Xu; Chen, Xiao-Wan; Wang, Zhen-Ning


    We wished to determine the effects of laparoscopic resection using natural orifice specimen extraction (NOSE) for patients with colorectal disease through a meta-analysis. A study search was undertaken in PubMed, EMBASE, and Cochrane databases for eligible studies until December 2014. Duration of hospital stay, operation time, time to first flatus, pain score, cosmetic result, postoperative complications, and disease-free survival (DFS) were the main endpoints. The results were analyzed using RevMan v5.3. Nine clinical studies involving 837 patients were included for final analyses. Laparoscopic resection with NOSE had a shorter duration of hospital stay (weighted mean difference (WMD) = -0.62 days, 95 % confidence interval (CI) [-0.95, -0.28], p flatus (WMD = -0.59 days, 95 % CI [-0.78, -0.41], p < 0.01), less postoperative pain (WMD = -1.43, 95 % CI [-1.95, -0.90], p < 0.01), and postoperative complications (odds ratio (OR) = 0.51, 95 % CI [0.36, 0.74], p < 0.01) with better cosmetic result (WMD = 1.37, 95 % CI [0.59, 2.14], p < 0.01). However, the operation time was significantly longer in the NOSE group (WMD = 20.97 min, 95 % CI [4.33, 37.62], p = 0.01). No significant difference was observed in DFS (hazard ratio (HR) = 0.88, 95 % CI [0.49, 1.57], p = 0.67). Our meta-analysis supported the notion that laparoscopic resection with NOSE for colorectal disease can significantly reduce the duration of hospital stay, accelerate postoperative recovery with better cosmetic results, and in particular, result in less postoperative pain and fewer complications.

  10. Armature Guide Ring Automation Assembly Equipment Feeding Mechanism Design Based on TRIZ%基于 TRIZ 的导向环自动装配设备上料机构设计

    周为; 王剑彬; 向友


    针对雨刮器电机自动化生产线配套设备,电枢导向环自动装配设备结构设计中如何高效、稳定供料的问题,提出运用T RIZ创新设计方法中的冲突解决原理进行电枢导向环自动装配设备的上料机构设计。通过分析上料机构功能设计需求与T RIZ中39个工程参数的关系,建立上料机构的矛盾矩阵,用冲突解决原理进行分析,找到相应的原理解,结合传统设计经验提出设计方案并评估,最终确定了电枢导向环自动装配设备上料机构的设计方案。%To design an efficient and stable armature guide ring automation assembly equipment in wiper motor automation production line ,the paper put forward using the conflict resolution principle of TRIZ to design the feeding mechanism .Through the analysis on the relationship of the functional design requirements and 39 engineering parameters in TRIZ ,the contradictions matrix of feeding mechanism was set up ,and analyzed by the conflict resolution principle ,the corresponding original solution was found .Combined with traditional design experience ,the design scheme was put forward and evaluated ,eventually the armature guide ring automation assembly equipment feeding mechanism was designed .

  11. Assessment of the therapeutic efficacy and safety of natural orifice transluminal endoscopic surgery in patients with fulminant acute pancreatitis

    ZHU Huiming


    Full Text Available ObjectiveTo evaluate the therapeutic effect of natural orifice transluminal endoscopic surgery (NOTES intervention in a cohort of patients treated for fulminant acute pancreatitis (FAP over a five-year period. MethodsBetween September 2007 and June 2012, 24 patients were treated with NOTES within 72 h of FAP onset and included 18 males and six females between the ages of 21-76 years old. The procedure was performed via the mouth to the stomach wall for penetration into the abdominal cavity and extraction of the inflammatory secretion followed by saline washes and lavage tube placement. Abdominal cavity lavage and peritoneal dialysis were carried out for one week. Outcome measures included abdominal pressure, bowel sounds, serum levels of inflammatory markers (tumor necrosis factor-alpha (TNFα, interleukin (IL-6, and IL-8, recovery time, and APACHE II score Data were analyzed using the Chi-squared test or F-test. ResultsIn 19 patients, the peritoneal effusion fluid volume removed during the NOTES procedure ranged from 200-2100 ml, and involved serous (n=7, blood (n=5, cellulose (n=5, and suppurative (n=2 fluids. In four patients, the lesser omental bursa effusion fluid volume ranged from 460-2500 ml, and involved serous (n=2 and blood (n=2 fluid. Abdominal pressure had decreased by day 2 after the NOTES procedure (8.60±2.65 vs. admission: 29.2±5.6 cm H2O. Intestinal peristalsis (admission: 1.68±1.02 times/minute was resolved by day 6 after the NOTES procedure (4.30±1.75 times/minute. Serum levels of TNFα, IL-6, and IL-8 were decreased significantly after the NOTES procedure (admission vs. day 6, all P<0.01. In addition, APACHE II score decreased after the NOTES procedure (admission: 12.76±6.68 vs. day 6: 6.46±1.84. The cure rate was 95.8%, and only one patient died (due to progressive multiple organ failure. The mean duration of hospital stay was 21.98±7.88 days. ConclusionNOTES intervention with extraction of the inflammatory

  12. Comparison between cardiovascular magnetic resonance and transthoracic doppler echocardiography for the estimation of effective orifice area in aortic stenosis

    Larose Eric


    Full Text Available Abstract Background The effective orifice area (EOA estimated by transthoracic Doppler echocardiography (TTE via the continuity equation is commonly used to determine the severity of aortic stenosis (AS. However, there are often discrepancies between TTE-derived EOA and invasive indices of stenosis, thus raising uncertainty about actual definite severity. Cardiovascular magnetic resonance (CMR has emerged as an alternative method for non-invasive estimation of valve EOA. The objective of this study was to assess the concordance between TTE and CMR for the estimation of valve EOA. Methods and results 31 patients with mild to severe AS (EOA range: 0.72 to 1.73 cm2 and seven (7 healthy control subjects with normal transvalvular flow rate underwent TTE and velocity-encoded CMR. Valve EOA was calculated by the continuity equation. CMR revealed that the left ventricular outflow tract (LVOT cross-section is typically oval and not circular. As a consequence, TTE underestimated the LVOT cross-sectional area (ALVOT, 3.84 ± 0.80 cm2 compared to CMR (4.78 ± 1.05 cm2. On the other hand, TTE overestimated the LVOT velocity-time integral (VTILVOT: 21 ± 4 vs. 15 ± 4 cm. Good concordance was observed between TTE and CMR for estimation of aortic jet VTI (61 ± 22 vs. 57 ± 20 cm. Overall, there was a good correlation and concordance between TTE-derived and CMR-derived EOAs (1.53 ± 0.67 vs. 1.59 ± 0.73 cm2, r = 0.92, bias = 0.06 ± 0.29 cm2. The intra- and inter- observer variability of TTE-derived EOA was 5 ± 5% and 9 ± 5%, respectively, compared to 2 ± 1% and 7 ± 5% for CMR-derived EOA. Conclusion Underestimation of ALVOT by TTE is compensated by overestimation of VTILVOT, thereby resulting in a good concordance between TTE and CMR for estimation of aortic valve EOA. CMR was associated with less intra- and inter- observer measurement variability compared to TTE. CMR provides a non-invasive and reliable alternative to Doppler-echocardiography for the

  13. IMELDA transvaginal approach to ectopic pregnancy: diagnosis by transvaginal hydrolaparoscopy and treatment by transvaginal natural orifice transluminal endoscopic surgery.

    Baekelandt, Jan; Vercammen, Jona


    To demonstrate a new minimally invasive approach for the diagnosis and treatment of ectopic pregnancy. Stepwise explanation of the technique using original video footage. Hospital. Since 2014, 15 patients were treated transvaginally for ectopic pregnancy and pregnancy of unknown location (PUL). In case of a diagnosis of ectopic pregnancy on ultrasound, a 2.5-cm colpotomy is made under general anesthesia, and the ectopic pregnancy is treated by transvaginal natural orifice transluminal endoscopic surgery (vNOTES) salpingectomy or salpingostomy. In case of a PUL on ultrasound, transvaginal hydrolaparoscopy (TVHL), an established technique for fertility exploration under local or general anesthesia, is used to investigate. If a tubal pregnancy is confirmed on TVHL, the colpotomy is extended to a 2.5-cm incision, and the ectopic pregnancy is treated transvaginally by vNOTES. If the TVHL investigation of the pelvis is negative (fallopian tubes and ovaries are normal), the procedure is stopped and the patient is followed up further. If the TVHL is inconclusive, the NaCl is drained and CO2 is insufflated (requiring general anesthesia) through the 4-mm TVHL port to improve visualization. Again, an ectopic pregnancy is then treated by vNOTES, and in case of a negative investigation the procedure is stopped and the patient is followed up further. Successful diagnosis and treatment of ectopic pregnancies. All patients were successfully operated without complications or conversions to standard laparoscopy. Twelve patients were treated by vNOTES for ectopic pregnancy. Three TVHL explorations for PUL were negative, and these patients were followed up; two patients developed a normal intrauterine pregnancy, and the third patient was treated with methotrexate for persistent asymptomatic raised hCG levels. Transvaginal hydrolaparoscopy and vNOTES are complementary techniques enabling gynecologic surgeons to explore PUL and treat ectopic pregnancies via minimally invasive

  14. 发动机喷嘴内部空化初生的数值模拟研究%Numerical Simulation of Cavitation Inception in Engine Orifice

    沃恒洲; 姚智华; 张亚芳; 王国丰; 徐玉福; 胡献国


    This paper investigated the effects of fluid characteristics and orifice geometry on cavitation inception in orifice.A full cavitation model was implemented in case of the fluids with different properties(viscosity,vapor pressure and surface tension) and the orifice with different geometries(inlet radius and length-to-radius(L/d) ratio).The formation and development of cavitation inside the orifice were analyzed quantitatively based on both parameters of critical cavitation pressure and critical cavitation number.According to the numerical simulation,it is revealed that the critical cavitation pressure increases with the increase of fluid viscosity and the decrease of vapor pressure of fluid.But the surface tension of fluid has not relative with cavitation inception.The critical cavitation pressure also increases with inlet radius and length-to-radius ratio.In case of fluids with same viscosity and same orifice,the critical cavitation number has little variation,though the critical cavitation pressure would change with variation of vapor pressure of fluids.Both of critical cavitation pressure and critical cavitation number change from the variations of frictional loss between the wall and fluids,flow direction due to different geometries of orifice;and from the continuity variation in-side fluids due to the variation of fluid properties.%采用全空化模型研究了具有不同物性(黏性、饱和蒸汽压和表面张力)的流体在不同几何形状(入口圆角半径和长径比)喷嘴中的空化现象,用临界空化压力和临界空化数对不同条件下空化的初生进行了分析与表征。结果表明:流体的黏性越大,饱和蒸汽压越小,空化初生的临界压力就越大,而表面张力对临界空化压力没有影响;在入口圆角半径较大和喷嘴长径比较大的喷嘴中,临界空化压力较大,在流体黏性和喷嘴几何形状相同的情况下,虽然临界空化压力会随着流体饱和蒸汽压

  15. 孔板水力空化装置的数值模拟%Simulation of Hydrodynamic Cavitation Equipment with Orifice Plates

    章昱; 李育敏; 计建炳


    基于FLUENT软件,采用]k-ω模型对孔板水力空化进行数值模拟,将相同条件下模拟所得的空化区与实验空化区进行比较.结果表明,模拟计算得到的汽含率分布与实验拍摄的汽含率分布相似,k-ω模型模拟结果与实验结果吻合.采用该模型分析了不同入口压力、孔板结构参数、液体物性参数对空化强度的影响,模拟结果表明,入口压力越大,空化强度越剧烈;增加孔径和孔的数量使空化强度减弱;增大液体密度和粘度使空化强度减弱;增大液体初始含气量使空化强度先增大后减小.%Based on the software FLUENT, the hydrodynamic cavitation with orifice plates was simulated using the k-ω model. The simulation results were compared with experimental data at the same situations, which showed that the distribution of vapor fraction by simulation was similar to that of experiment. The influences of inlet pressure, structures of orifice plate and physical characters of liquid on cavitation intensity were investigated by simulation using this model. The intensity of cavitation increased with increasing of inlet pressure and the orifice diameter and number. The intensity of cavitation decreased as the increase of density and viscosity of liquid, when the initial gas holdup increased, the intensity of cavitation increased first and then weaken.

  16. Mass flow rate measurements in gas-liquid flows by means of a venturi or orifice plate coupled to a void fraction sensor

    Oliveira, Jorge Luiz Goes; Passos, Julio Cesar [Departamento de Engenharia Mecanica-LEPTEN/Boiling-UFSC, Campus Universitario, Trindade, 88.040-900 Florianopolis-SC (Brazil); Verschaeren, Ruud; Geld, Cees van der [Eindhoven University of Technology, Faculty of Mechanical Engineering, W-hoog 2.135, P.O. Box 513, 5600 MB, Eindhoven (Netherlands)


    Two-phase flow measurements were carried out using a resistive void fraction meter coupled to a venturi or orifice plate. The measurement system used to estimate the liquid and gas mass flow rates was evaluated using an air-water experimental facility. Experiments included upward vertical and horizontal flow, annular, bubbly, churn and slug patterns, void fraction ranging from 2% to 85%, water flow rate up to 4000 kg/h, air flow rate up to 50 kg/h, and quality up to almost 10%. The fractional root mean square (RMS) deviation of the two-phase mass flow rate in upward vertical flow through a venturi plate is 6.8% using the correlation of Chisholm (D. Chisholm, Pressure gradients during the flow of incompressible two-phase mixtures through pipes, venturis and orifice plates, British Chemical Engineering 12 (9) (1967) 454-457). For the orifice plate, the RMS deviation of the vertical flow is 5.5% using the correlation of Zhang et al. (H.J. Zhang, W.T. Yue, Z.Y. Huang, Investigation of oil-air two-phase mass flow rate measurement using venturi and void fraction sensor, Journal of Zhejiang University Science 6A (6) (2005) 601-606). The results show that the flow direction has no significant influence on the meters in relation to the pressure drop in the experimental operation range. Quality and slip ratio analyses were also performed. The results show a mean slip ratio lower than 1.1, when bubbly and slug flow patterns are encountered for mean void fractions lower than 70%. (author)

  17. Balanced Flow Measurement and Conditioning Technology (Balanced Orifice Plate 7,051,765 B1) for NASA Inventions and Contributions Board Invention of the Year Evaluation

    Kelley, Anthony R.


    This viewgraph document reviews the Balanced Flow Measurement (BFM) and Conditioning Technology, and makes the case for this as the NASA Invention of the Year. The BFM technology makes use of a thin, multi-hole orifice plate with holes sized and placed per a unique set of equations. It produces mass flow, volumetric flow,kinelic energy,or momentum BALANCE across the face of the plate. The flow is the square root of upstream to downstream differential pressure. Multiple holes lead to smoother pressure measurement. Measures and conditions or can limit fluid flow. This innovation has many uses in and out of NASA.

  18. 具有孔道沉槽的滑阀过流面积分析%Analysis of Orifice Area of Slide Valve with Sinking Grooves

    张立杰; 王力航; 王帅; 李德新


    Multiple valve with its high degree of integration was widely used in the field of engi-neering machinery,where the valve port form possessed a very important impact on flow control char-acteristics.Aiming at the cylindrical and conical valve orifice of the spool valve with grooves on the valve body,and based on the structural characteristics and pressure distribution and velocity changes of the internal flow field,and with the equivalent orifice area theory,the calculation equations of ori-fice area of the cylindrical and conical valve orifice were proposed and analyzed.The results were correc-ted by the flow field simulation,and the accuracy of the results was verified by experiments.The study results have some reference values for the design and performance prediction of the hydraulic master valve.%多路阀以其高集成度被广泛应用于工程机械领域,其中阀口形式对多路阀流量控制特性具有重要影响。对于阀体上开有孔道沉槽、节流面为常见的圆柱面和圆锥面两种滑阀阀口形式的多路阀,根据其结构特征及内部流场压力分布和速度变化情况,利用等效阀口面积理论,推导了圆柱面阀口和圆锥面阀口过流面积计算公式。利用流场仿真对计算结果进行了修正,采用实验手段验证了计算结果的准确性。研究结果对滑阀阀芯的多路阀设计及性能预测具有一定参考价值。

  19. Pemodelan Dan Analisis Pengaruh Variasi Oli dan Diameter Orifice terhadap Gaya Redam Shock Absorber Dan Respon Dinamis Sepeda Motor Yamaha Jupiter Z 2008

    Newanda Asa Wahid


    Full Text Available Sepeda motor merupakan moda transportasi yang paling banyak diminati oleh masyarakat Indonesia. Dalam hal kenyamanan, maka komponen sepeda motor yang berperan penting adalah sistem suspensi. Sistem suspensi berfungsi menyerap getaran berlebih akibat profil permukaan jalan, sehingga meningkatkan kenyamanan dan keamanan. Oleh karena itu, perlu dilakukan penelitian untuk mendapatkan sistem suspensi yang terbaik. Dalam tugas akhir ini dilakukan pemodelan dan analisis pengaruh perubahan parameter sistem suspensi sepeda motor Yamaha Jupiter Z 2008 khususnya pada komponen monotube hydraulic shock absorber yang didasarkan pada pemodelan setengah kendaraan. Parameter yang divariasikan adalah tipe oli dan diameter orifice, dimana terdapat 5 macam tipe oli dengan rentang nilai massa jenis (ρ sebesar 845 – 874 kg/m3, dan viskositas (ν sebesar 11,3 – 46 mm2/s, sementara untuk diameter orifice yaitu saat kompresi (Docomp sebesar 1,2 – 1,5 mm, saat ekspansi (Doexp sebesar 0,8 – 1 mm. Input yang digunakan pada simulasi adalah input sinusoidal dan input bump modified. Dari penelitian ini didapatkan hasil bahwa sistem suspensi modifikasi monotube hydraulic shock absorber yang menghasilkan gaya redam optimal memiliki nilai parameter viskositas kinematis oli 46 mm2/s, massa jenis oli 845 kg/m3, diameter orifice kompresi 0,00135 m, dan diameter orifice ekspansi 0,0009 m. Nilai gaya redam optimal yang dihasilkan sistem suspensi modifikasi adalah sebesar 1171,3 N, lebih tinggi hingga 546,44 N dibandingkan dengan gaya redam sistem supensi asli yang bernilai 624,86 N pada frekuensi 2 Hz. Pada sistem setengah kendaraan motor dengan penggunaan sistem suspensi asli maupun modifikasi, untuk input bump, respon kendaraan dan penumpang mencapai steady state kurang dari 2 detik dan 5 detik, sedangkan untuk input sinusoidal responnya mencapai steady state kurang dari 2 detik dan 3 detik. Penggunaan suspensi asli maupun modifikasi menghasilkan nilai perpindahan RMS yang

  20. 无凸轮轴发动机电液驱动配气机构阻尼孔优化设计%Optimization of Orifices on Electro-hydraulic Control Camless Valve Actuator

    谷艳华; 胡乃硕; 高峰军; 李华; 王有坤; 郭英男


    The optimized design of orifices in the electro-hydraulic control valve actuator will affect the response and the impact of valve in the camless engine, and thus affect all aspects performance of engine. The mathematical model of the orifices in the valve actuator was designed, and the effects of the orifice ' s diameter to the velocity during opening and landing were analyzed. The model of the camless electro-hydraulic valve actuator was built by using AMESim, the analysis of the influence to the diameter and related position of the valve orifices was done, the results showed that the orifice diameter decreased or the related position of damping chamber orifice increased resulted in the delay of opening time, and the orifice diameter decreased or the related position of main line orifice decreased resulted in the delay of closing time. The parameters of orifices diameter and position were optimized, and the demand of the valve was met by the optimized parameters through the experiments.%无凸轮轴发动机电液驱动配气机构中节流阀阻尼孔的优化设计直接影响气门运动及时响应性能和气门落座冲击性能,进而影响发动机性能.建立了配气机构中节流阀阻尼孔的数学模型,并利用该模型研究了阻尼孔直径对气门开启和落座的影响.使用AMESim搭建了配气机构的仿真模型,研究阻尼孔孔径和相对位置对气门运动的影响.结果表明,阻尼孔直径减小或者阻尼腔阻尼孔相对位置上升会使气门延迟开启;阻尼孔直径减小或者主油路阻尼孔相对位置下降会使气门延迟关闭.优化了阻尼孔孔径和位置参数,试验表明阻尼孔优化设计结果满足发动机对配气机构中气门运动的要求.

  1. 单级同步感应线圈炮电枢的磁场-温度场有限元分析%Finite element analysis of magnetic-thermal fields for armature in single-stage synchronous induction coilgun

    邹本贵; 曹延杰; 王成学; 尚永爽


    In order to analyze the temperature of the armature and the main influencing factor during the launching process of single-stage synchronous induction coilgun (SSICG), the numerical model of the SSICG for magnetic field and thermal field coupling was set up based on the theory of transient eddy current field and numerical heat transfer (NHT). Finite element analysis (FEA) model of armature and drive coil were established with parametric design language (APDL). Decentralized joule heat induced in the armature during the launching process of the SSICG was coupled into the thermal field as heat generation rate. The FEA of the armature was carried out by direct coupled-field analysis. Research results show that the eddy current and temperature in armature display non-uniform distribution and reach the maximal value around the periphery of the armature in the tail. The maximal temperature value is 70. 29℃. The temperature rise in armature was increasing as the current loads increases. Increasing the over-all heat transfer coefficient and emissivity, decreasing the initial temperature can reduce the temperature rise in armature. Increasing thermal conductivity can decrease the maximal difference in temperature.%为了研究电枢在同步感应线圈炮发射过程中的温度分布规律以及影响电枢温度分布的因素,依据瞬态涡流场和计算传热学的相关理论建立单级同步感应线圈炮电枢磁场-温度场耦合分析的数学模型,利用APDL建立了电枢和驱动线圈的有限元模型,将线圈炮发射过程中电枢中感应的焦耳热损耗作为体积热源,通过顺序耦合的方法实现电枢的磁场一温度场有限元分析.研究结果表明:电枢中感应的涡流和温度分布不均匀,当电流载荷最大时,电枢中的感应的涡流最大、温升最高,最高温度达70.29℃,且都位于电枢的底部的外侧;随着加载电流载荷的增大电枢的温升愈大;增大电枢表面的对流换热系数、

  2. 静止条件下多种轨道—电枢形状的轨道炮电流分布仿真%Finite Element Simulation on Current Distribution Feature of Multiple Rail-Armature Structures for EM Rail Launchers under Static Conditions

    解世山; 吕庆敖; 郭春龙


    针对等轨道截面、等炮口截面、等长度、等材料和等电流8种典型的轨道—电枢结构,在电枢速度为0 m/s的情况下,采用Ansoft12有限元分析软件,仿真分析电流分布特征,得到:矩形截面轨道—长方体结构电枢的轨道炮有最不均匀的电流分布特征,电流主要分布在轨道外表面和电枢后部凹表面,并且分别对应于趋肤效应和电流短路径聚集现象,跑道形截面的轨道—回转体结构电枢的轨道炮有最均匀的电流密度分布.%Abstract;In this paper, electric current density of eight typical armature-rail structures with the same values of the rail section area, the muzzle section area, the rails'length, the material and circuit current under static condition are contrastively analyzed by Ansoftl2. The results indicate the following: the current is mainly distributed on the outer skin of the rails and the back skin of the armature;the launcher with runway-shaped cross section rail and rotor armature structure has the most even electric current distribution; and launcher with rectangle-cross-section rad and cuboid armature structure has the most uneven electric current distribution.

  3. Eustachian orifice malignant melanoma:a case report%咽鼓管口恶性黑色素瘤1例

    苏振福; 武文明; 潘家菊


    The patient, a 52 year old male was admitted to the hospital,because of right hearing loss before three months. Six months ago, the patient had the right former group sinusitis and nasal polyps, and had the right former group sinus open and polypectomy operation outside the hospital. The surgery was uneventful and the postoperative dressing was done. He has no history of tinnitus, earache, ear pus, epistaxis, headache, dizziness. Physical examination on admission shows the right external auditory canal was clean, tympanic membrane integrity, pale yellow, mild depression, and poorly eardrum movement. The electronic nasopharyngoscopy show a black mass in the edge of the anterior lip of the right eustachian tube. The mass has a smooth surface, and only seen partly. Nasopharynx magnetic resonance shows in the right pharyngeal orifice visible there was a round short T2 node, maximum diameter of 13 mm, the border was clear. The parapharyngeal space had been compressed which close to the right eustachian tube torus. After the scan enhanced, the lesions was strengthened. The pure tone audi-ometry shows right mild conduction deafness, and the acoustic impedance showing right type B tympanogram curve. Eardrum puncture extracted got about 0. 2 ml yellow liquid. Otitis media with effusion is considered. A biopsy is taken by means of the nasal endoscopic. The pathology report is the right eustachian orifice malignant melanoma. The immunohistochemical examination (Horton-Magath-Brown 45) showed a positive reaction.

  4. Experimental otitis media with effusion induced by electron beam irradiation to pharyngeal orifice of auditory tube in guinea pig. A preliminary report

    Kokubu, Michiyo; Amatsu, Mutsuo (Kobe Univ. (Japan). School of Medicine)


    The purpose of the present study was to obtain a more natural tubal insufficiency than that obtained by the conventional methods to clarify the middle ear pathology associated with tubal dysfunction. For this purpose, the pharyngeal orifice of the auditory tube in the guinea pigs was irradiated with electron beam with a dose of 2,000 rad following the preliminary experiments to determine the appropriate dose. The guinea pigs with intact drum and normal Pryer reflex were used for the present experiment series. A specially devised apparatus was used for avoiding the dipersing beam. Histopathological changes of the middle ear and auditory tube were observed in a series of single specimen with H-E staining 1, 2, 3, 6, 12 months after irradiation. In this study, middle ear with effusion was used to clarify the dynamic process of the pathological changes between the auditory tube and the middle ear. In summary, the present study revealed that the electron beam irradiation to the pharyngeal orifice caused various grades of otitis media with effusion which could be classified into three groups. Of these groups 1) and 2), 3) were likely to be corresponding with so-called serous and purulent otitis media with effusion in human respectively. Infection due to the malfunction caused by the epithelial damage of the auditory tube was an important promoting factor to change the serous type effusion for the purulent type effusion.

  5. Positioning the instillation of contrast at the ureteral orifice cystography can be useful to predict postoperative contralateral reflux in children with unilateral vesicoureteral reflux.

    Matsumoto, Fumi; Shimada, Kenji; Matsui, Futoshi; Itesako, Toshihiko


    The aim of the present study was to evaluate the usefulness of positioning the instillation of contrast at the ureteral orifice (PIC) cystography in prediction of postoperative contralateral reflux in patients with unilateral vesicoureteral reflux (VUR) undergoing ureteral reimplantation. Between January 2007 and March 2009, 34 children (20 boys and 14 girls) had antireflux surgery for unilateral primary VUR. This was diagnosed by conventional fluoroscopic voiding cystourethrography (VCUG) in all patients. After induction of general anesthesia, PIC cystography was carried out immediately before ureteral reimplantation by instilling contrast material at the ureteral orifice. Patients with positive PIC cystogram on the contralateral side underwent bilateral ureteral reimplantation via the Cohen technique. VCUG was repeated at 6-12 months postoperatively. Of the 34 patients, 16 (47%) showed VUR on the contralateral side on PIC cystography and underwent bilateral reimplantation. The remaining 18 patients (53%) with negative PIC cystogram underwent unilateral reimplantation, and no VUR was detected by postoperative VCUG in all ureters. None of the 34 patients had surgical complications or recurrent urinary tract infections. In conclusion, PIC cystography represents a useful tool to predict new onset contralateral VUR in patients with unilateral VUR on conventional VCUG.

  6. Modeling and Simulation of Armature Assembly of Double-stage Dual-Nozzle-flapper Electro-hydraulic Servo Valve%两级双喷嘴挡板电液伺服阀衔铁组件的建模与仿真

    王新晴; 王文夫


    A detailed analysis and mathematical modeling of armature assembly of double⁃stage dual⁃nozzle⁃flapper electro⁃hy⁃draulic servo valve were given. On basis of this, the process of sub⁃model modeling and parameter setting of armature assembly self⁃de⁃fined with AMESet software were expatiated. A complete servo valve model of the nozzle flapper was built. It is proven by the graph got⁃ten in the simulation run, the effectiveness of the model of armature assembly and the complete servo valve model of the nozzle flapper.%对两级双喷嘴挡板电液伺服阀中的衔铁组件进行了物理模型分析和数学建模,并在此基础上,阐述了利用AMESet软件自定义建立衔铁组件子模型的过程和参数设置。建立了两级双喷嘴挡板电液伺服阀整体的模型,仿真运行获得的曲线证明了衔铁组件子模型和两级双喷嘴挡板电液伺服阀整体模型的有效性。

  7. Design and Analysis of Throttle Orifice Applying to Small Space with Large Pressure Drop%适用于大压降小间距管道的节流件设计及分析

    李妍; 陆道纲; 曾小康


    节流件广泛应用于核电站各类管道系统中,对于大压降和短距离的管道系统,节流孔板设置不合理将导致管道振动程度加剧并伴随节流件的孔径、厚度、偏心度和倒角等关键结构参数对节流效果的敏感性进行分析和计算,在此基础上,提出适用于大压降小间距管道的节流件为多级偏心节流孔板.计算表明:多级偏心节流孔板可有效抑制汽蚀和闪蒸的发生,节流效果较好,适用于大压降小间距管道节流.%Throttle orifices are widely used in various pipe systems of nuclear power plants.Improper placement of orifices would aggravate the vibration of the pipe with strong noise,damaging the structure of the pipe and the completeness of the system.In this paper,effects of orifice diameter,thickness,eccentric distance and chamfering on the throttling are analyzed applying CFD software.Based on that,we propose the throttle orifices which apply to small space with large pressure drop are multiple eccentric orifices.The results show that the multiple eccentric orifices can effectively restrain the cavitation and flash distillation,while generating a large pressure drop.

  8. Injection and spray characteristics of a variable orifice nozzle applied the jerk type fuel injection pump for DI diesel engine; Jerk shiki nenryo funsha pump wo mochiita kahen funko nozzle no funsha funmu tokusei

    Hasegawa, T.; Matsui, K.; Iwasaki, T.; Kobayashi, T. [Zexel Corp., Tokyo (Japan); Matsumoto, Y. [The University of Tokyo, Tokyo (Japan)


    A Variable Orifice Nozzle (VON) by changing a cross-sectional area of the nozzle injection hole, for improving a rate of injection and injection duration, has been developed to study its injection and spray characteristics. The nozzle geometry was optimized to analyze a nozzle internal flow by computational method. Results show that, injection and spray pattern responded to the nozzle orifice cross-sectional area which is changing larger to smaller in the part load range. This results suggest to contribute a combustion improvement which decreasing NOx and soot. 14 refs., 10 figs.

  9. 动静组合密封在电动工具转子轴上的应用%Application of Dynamic-Static Sealing Structure on Power Tool Armature Shaft

    李振; 康玉茹


    Sealing life is a key factor to influences the tool life,and an important index for judging the power tool per-formance.The structure and principle of lip seal was introduced.A sealing system included dynamic and static sealing used in the power tool armature shaft was introduced.The sealing lip strain and stress under working conditions was analyzed by using ABAQUS /CAE,and the sealing life was tested by experiment.The simulated and test results prove the effectiveness of this sealing system.%密封寿命是影响电动工具适用寿命的关键因素和衡量电动工具性能的重要指标。简述唇形油封的密封结构和原理,分析电动工具转子轴动-静组合密封系统的机构和工作原理,对工作状态下油封唇口的位移和应力分布进行仿真,并通过试验验证密封系统的有效性。

  10. Coronary artery and orifice development is associated with proper timing of epicardial outgrowth and correlated Fas-ligand-associated apoptosis patterns.

    Eralp, Ismail; Lie-Venema, Heleen; DeRuiter, Marco C; van den Akker, Nynke M S; Bogers, Ad J J C; Mentink, Monica M T; Poelmann, Robert E; Gittenberger-de Groot, Adriana C


    The proepicardial organ provides differentiated cell types to the myocardial wall and facilitates coronary development. Ingrowth of the coronary arteries into the aorta has recently been linked to apoptosis. This study was set up to examine the effect of an inhibition of epicardial outgrowth on apoptotic patterning and coronary development. Epicardial outgrowth was blocked at HH15-17 in quail embryos, which survived until HH25-35 (n=33). Embryos with complete inhibition of outgrowth did not survive after HH29. These embryos presented with thin compact myocardium, devoid of vessels. In embryos with delayed epicardial outgrowth the phenotype was less severe, and surviving embryos were studied up to HH35. In these embryos, myocardial vascularization was poor and apoptosis in the peritruncal region at HH30 was diminished. Embryos at HH35 displayed an abnormal coronary network and absent coronary orifices. In a further set of experiments (n=10), outgrowth was inhibited in chicken embryos at HH15, followed by transplantation of a quail proepicardial organ into the pericardial cavity to rescue cardiac phenotype. These chimeras were studied at HH29 and HH35. Myocardial development was restored; however, in 3 of 4 embryos (HH35), the coronary orifices were absent. Examination of double stainings of quail-chicken chimeras revealed that EPDCs produce Fas ligand as an apoptotic inductor at sites of coronary ingrowth. In the absence of proper timing of epicardial outgrowth, myocardial development and vascularization are disturbed. Also apoptosis in the peritruncal region is diminished. During later development, this leads to defective or absent connections of the coronary system to the systemic circulation.

  11. Relation between three-dimensional geometry of the inflow tract to the orifice and the area, shape, and velocity of regurgitant color Doppler jets: an in vitro study.

    Nicolosi, G L; Budano, S; Grenci, G M; Mangano, S; Cervesato, E; Zanuttini, D


    The relation between three-dimensional geometry of the inflow tract to the orifice and the area, shape, and velocity of regurgitant jets was studied in a pulsatile in vitro color Doppler flow model. A 2.5 MHz transducer connected to a diagnostic ultrasound machine was placed in a water tank facing pulsatile jets (duration, 0.5 second) obtained by a calibrated injector. Flow rate from 6 to 52 ml/sec were tested through a 5 mm diameter circular orifice. Four different three-dimensional inflow tract geometries were compared: (A) sharp-edged, (B) Venturi (funnel), (C) converging conical, and (D) diverging conical. Mean velocities of jets were measured by continuous-wave Doppler echocardiography. Driving pressures were also measured by means of a fluid-filled catheter. Two observers independently digitized contours of maximal color jet areas by computer system from two separate sets of experiments. Results are given as the mean values of the four measurements for each parameter. Jet areas were correlated to flow rate, with no difference from A through D. The shape (eccentricity) of jets was different between A and B (p less than 0.05), between B and D (p less than 0.01), and between C and D (p less than 0.01). The shape of jets was correlated with flow rate, continuous-wave velocity, and pressure gradient in B, C, and D but not in A. Measured pressure gradients and estimated gradients by continuous-wave Doppler echocardiography were similarly correlated from A through D.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Progress on natural orifice transluminal endoscopic surgery%经自然腔道内镜外科学(NOTES)研究进展

    王子恺; 李闻


    Natural orifice transluminal endoscopic surgery (NOTES) has gained a great deal of attention from the surgical and gastroenterology communities all over the world since its introduction. The safety and feasibility of NOTES has been confirmed by plenty of well-designed experimental studies. Furthermore, many clinical studies have discussed transesophageal, transgastric, transvaginal and transrectal access for a variety of NOTES procedures. Meanwhile, innovation of the multitasking platforms and endoscopic devices for NOTES and their clinical application have been reported. This article reviews various access techniques for NOTES procedures, discusses the latest clinical studies in the field of NOTES, and presents the advantages of multitasking platforms and endoscopic devices for NOTES.%经自然腔道内镜外科学( natural orifice transluminal endoscopic surgery,NOTES)概念自提出以来,受到内镜医师和腹腔镜医师的广泛关注,成为微创技术领域研究和争论的焦点.国内外NOTES实验研究已经证实了NOTES的安全性、可行性及有效性,有关NOTES临床应用的研究也大量发表.同时,有关NOTES操作平台、器械研发和临床应用的报道也不断增多.本文就目前NOTES临床应用进展和相关的操作平台、器械的研发及应用情况进行概述.

  13. Software development for a orifice plate characterization used in the oil and gas industry; Desenvolvimento de um 'software' para caracterizacao de placas de orificio utilizadas na industria do petroleo

    Andreas, N. Andreas [Universidade Federal de Itajuba (UNIFEI), MG (Brazil)


    The petroleum industry is an economic area that has a strong impact, because this, the information precision is one of the most important facts and it is able to be defined with software simulation. The knowledge of the exactly quantify of petroleum is fundamental, and then the instrumentation is essential for this measurement. There are many mechanisms to measure the volume flow, and one of the most used is the Orifice Plates, which has been more common in the Natural Gas Industry. The software development goal is the characterization of these Orifice Plates, allowing that the constant, which characterizes certain Plate, to be determined without Labor instruments, for that the software has an actualized database. But, the software needs some variables, that are responsible for the environment characteristics and the used material, to calculate the constant of the Orifice Plate, for example, fluid viscosity, environment temperature and kind of the Orifice Plate. The utilized equations in this software are based on the Stolz II equations. This tool is able to facilitate the work in petroleum industry, besides it is done for mobile applications, allowing analyses in real time. (author)


    景晓东; 孙晓峰


    Both the velocity of the sound-excited jet flow at asmall circular orifice and the nonlinear impedance of the orifice are measured at high sound intensity. As the sound pressure level isincreased, the velocity of the sound-excited jet flow increases. Inthe present experiment the flow velocities in the orifice coverap proximately the range of 0 to 19 m/s, thereby showing that a type ofstrong acoustic streaming occurs. Consequently the orifice resistan cemarkedly increases with the increase of the SPL while theorifice reactance decreases to 0.7 of its linear value at itslowest point. Besides, the present experiment has verified one previou sdiscrete vortex model of the acoustic nonlinearity of a circular orifice.%在高声强下测量了微圆孔处声激发射流的速度和微圆孔的非线性声阻抗。随声压级的增加声激发射流的速度增大,实验中射流速度在0-19m/s范围内变化,这表明出现一种强烈声整流现象;与此同时微圆孔声阻明显增大,而声抗减小,声抗最小值约是其线性值的0.7倍。此外实验结果还验证了一种微园孔声学非线性效应离散涡模型的合理性。

  15. Maximum ceasing angle of inclination and flux formula for granular orifice flow%颗粒孔洞流的最大休止倾角和流量公式

    彭政; 蒋亦民


    This work measured mass flux of a granular sample (glass beads) discharged from an inclined orifice for various inclination angles and orifice diameters. It is found that irrespective the orifice sizes, the fluxes all vary linearly with cosine of the inclination angle, and the linearly extrapolated angle of zero-flux, namely the critical angle of flow ceasing,increases linearly with ratio between grain and orifice diameter, tends to the angle of repose in the limit of infinite orifice diameter within an approximation of the Bagnold angle. The results show that the flux formula varying linearly with cosine of inclination angle is capable to reveal behaviors of the critical ceasing angle, a property that the Beverloo formula of which parameters vary with cosine of inclination angle can not describe.%实验测量了重力驱动下的玻璃珠颗粒样品通过不同倾角和孔径的圆形孔洞的卸载流量.发现无论孔径大小,流量均与倾角的余弦呈良好的线性关系;线性外推得到的零流量角,即流量休止临界角随颗粒粒径与孔洞直径之比的减小而线性增加;在无穷大孔径极限下,此临界角在Bagnold角的误差范围内与样品的安息角一致.这些结果表明流量随倾角余弦线性变化的经验公式能揭示临界角的行为和特性,这是参数随倾角变化的Beverloo公式所不能描述的.

  16. 高速永磁同步电机电枢电流谐波分析%Harmonic analysis of armature current for high speed permanent magnet synchronous motor

    于吉坤; 李立毅; 杜鹏程; 张江鹏


    在高速永磁同步电机谐波分析中,主要有解析和仿真两种方法。解析法则适用于连续系统,而仿真法适用于离散系统的,但两种方法之间关联性问题研究相对较少,针对此问题,提出一种基于空间矢量脉宽调制( SVPWM)技术电枢电流谐波解析法和仿真法内在关联的分析方法。根据连续函数和离散函数的傅里叶级数公式,分析了这两种方法在谐波计算中偏差的分布规律。分析结果表明,采样频率和负载是离散电枢谐波计算的主要影响因素,随着采样频率的升高电枢电流谐波呈现振荡阻尼衰减的特性,并收敛于连续系统的解析值,而负载则能降低振荡幅值和提高收敛速度。构建了基于DSP的永磁同步电机系统实验平台,实验结果验证了该分析方法的有效性。%There are two methods in harmonic analysis of the high speed permanent magnet synchronous motor, and they are analytical method and simulation method.The analytical method is suitable for con-tinuous systems, and the simulation method for discrete system.As the relevance of these two methods has been rarely studied, one correlation analysis method was proposed, which is based on the space vector pulse width modulation ( SVPWM) technology.From Fourier series of the continuous function and the discrete function,the deviation distribution law between these two methods in the harmonic calculation was analyzed.The analysis results show that the main influence factors of discrete harmonic calculation of ar-mature are sampling frequency and load condition.The armature current harmonics oscillate damping at-tenuation with increase in sampling frequency and converge to the analytical results of the continuous sys-tem.The oscillation amplitude is reduced and the convergence speed is improved by load.The permanent magnet synchronous motor system experiment platform based on DSP is constructed, and it is confirmed that the

  17. 电枢力作用下的电磁发射导轨及壁板的变形与应力分析%Deformation and stress analysis of rails and panels of rail guns under armatures' force

    白象忠; 何威; 赵建波; 司秀勇


      Rails and panels of rail guns are simplified as double beams with bi-layer elastic foundations. Based on the situation of rails and panels under armatures' force during rail guns' launch, differential balance equations are established. Analytical solutions of displacement and stress of double beams are obtained by influence function method. Analytical solutions are verified by the com-parison of them with ANSYS results in a sample problem. The results have a reference to strength and stiffness design of rail gun components.%  本文将电磁轨道发射装置的发射导轨及壁板简化为双层弹性地基梁。当电枢位于发射状态的某一位置时,在电枢接触力的作用下,建立了发射导轨及壁板的微分平衡方程。应用“影响函数”法,得到了双层梁位移和应力的解析解。通过算例,对发射导轨及壁板的变形和应力进行了分析,并将计算结果与 ANSYS 的分析结果进行了比较,相互佐证了解的可靠性。本文的研究结果可为电磁发射装置构件的强度、刚度设计提供依据。

  18. 先天性三尖瓣口无功能的超声心动图诊断%Diagnosis of congenitally unguarded tricuspid valve orifice by echocardiography

    吴力军; 张玉奇; 陈亚青; 陈丽君; 张志芳


    目的 分析先天性三尖瓣口无功能(congenitally unguarded tricuspid valve orifice,CUTVO)的超声心动图特征,评价超声心动图对CUTVO的诊断价值.方法 回顾性分析9例经心外科手术或尸解诊断为CUTVO患儿的超声心动图资料.结果 CUTVO声像图特征主要表现为三尖瓣叶完全或部分缺如,三尖瓣腱索及乳头肌缺如或发育不良,三尖瓣环及房室连接关系正常;三尖瓣口严重反流,右心房、右心室明显增大.本组单纯性CUTVO2例,合并其他心血管系统畸形7例,其中肺动脉闭锁伴室间隔完整5例,房间隔缺损及动脉导管未闭1例,肌部室间隔缺损1例.9例患儿中,超声诊断符合7例,误诊2例(22.2%),其中1例误诊为三尖瓣下移畸形,1例误诊为Uhl's病.结论 超声心动图技术可以准确诊断CUTVO,但需与三尖瓣下移畸形及Uhl's病鉴别.%Objective To review the imaging characteristics and evaluate the diagnostic value of echocardiography for congenitally unguarded tricuspid valve orifice (CUTVO).Methods Doppler echocardiography was performed and these images were compared with operative and necropsy findings in 9 children with CUTVO.Results CUTVO was characterized by the absence of the tricuspid valvar leaflets with normal atrioventricular junction and tricuspid annulus,severe tricuspid regurgitation,and dilated right atrium and right ventricles.The associated malformations included pulmonary atresia with intact ventricular septum (5 cases),patent ductus arteriosus and atrial septal defect (1 case),and muscular ventricular septal defect (1 case).Seven of 9 cases were diagnosed correctly,and other 2 cases were miss-diagnosed,in which 1 case misdiagnosed as Ebstein anomaly,and 1 case misdiagnosed as Uhl's disease.Conclusions Congenitally unguarded tricuspid valve orifice can be diagnosed accurately by Doppler echocardiography.This malformation should be distinguished from Ebstein anomaly and Uhl's disease.

  19. Linearized Euler Equations for the Determination of Scattering Matrices for Orifice and Perforated Plate Configurations in the High Mach Number Regime

    Moritz Schulze


    Full Text Available The interaction of a plane acoustic wave and a sheared flow is numerically investigated for simple orifice and perforated plate configurations in an isolated, non-resonant environment for Mach numbers up to choked conditions in the holes. Analytical derivations found in the literature are not valid in this regime due to restrictions to low Mach numbers and incompressible conditions. To allow for a systematic and detailed parameter study, a low-cost hybrid Computational Fluid Dynamic/Computational Aeroacoustic (CFD/CAA methodology is used. For the CFD simulations, a standard k–ϵ Reynolds-Averaged Navier–Stokes (RANS model is employed, while the CAA simulations are based on frequency space transformed linearized Euler equations (LEE, which are discretized in a stabilized Finite Element method. Simulation times in the order of seconds per frequency allow for a detailed parameter study. From the application of the Multi Microphone Method together with the two-source location procedure, acoustic scattering matrices are calculated and compared to experimental findings showing very good agreement. The scattering properties are presented in the form of scattering matrices for a frequency range of 500–1500 Hz.

  20. Characterization of the Micro-Orifice Uniform Deposit Impactor-droplet freezing technique (MOUDI-DFT) for size-resolved quantitative measurements of ice nuclei

    Mason, Ryan; Si, Meng; Li, Jixiao; Huffman, J. Alex; McCluskey, Christina; Levin, Ezra; Irish, Victoria; Chou, Cédric; Hill, Thomas; Ladino, Luis; Yakobi, Jacqueline; Schiller, Corinne; Abbatt, Jon; DeMott, Paul; Bertram, Allan


    Ice formation within a cloud system can significantly modify its lifetime and radiative forcing. Many current instruments for measuring atmospheric concentrations of ice nuclei (IN) are not capable of providing size-resolved information. Such knowledge is useful in identifying the sources of IN and predicting their transport in the atmosphere. Furthermore, those that use size-discrimination to identify IN typically exclude particles with an aerodynamic diameter greater than 2.5 μm from analysis. Several studies have indicated this may be an important size regime for IN, particularly with those activating at warmer temperatures. The recently developed Micro-Orifice Uniform Deposit Impactor-droplet freezing technique (MOUDI-DFT) addresses these limitations through combining sample collection by a model of cascade impactor with an established immersion freezing apparatus. Here we present a characterization of the MOUDI-DFT and the development of a modified technique which address experimental uncertainties arising from sample deposit inhomogeneity and the droplet freezing method. An intercomparison with a continuous-flow diffusion chamber (CFDC) was performed. We also show preliminary results from a campaign undertaken in a remote coastal region of western Canada. Correlations between atmospheric IN concentrations and the abundance of suspended submicron and supermicron particles, biological aerosols, carbonaceous aerosols, and prevailing meteorological conditions were investigated.

  1. Production Domesticization Research of Certain Adjustable Orifice%某型柴油机调喷器国产化研制

    王建国; 马茂; 郭巨寿; 王连宏; 于霞


    The adjustable orifice is a key part which can make certain large diesel engine ensure fuel injection system to supply oil exactly and stably in specific time. During early assembly, the imported parts are adopted which have long cycle and high cost. The paper analyzes the product structure and precision and researches adaptable technical tools, and optimizes technical program and bench test. On the basis of technical experiment, a key technique for manufacturing is broken through, which supplies reliable insurance for production domesticization.%调喷器是某型号大功率柴油机保证燃油喷射系统,能够在特定的时间条件下准确、稳定地供油的关键件。前期装配一直采用进口件,周期长,成本高。通过针对产品结构与精度的分析,研究了适宜性工装,优化和改进了工艺方案及试验台的改造研究,并在工艺试验的基础上,突破了加工的关键技术,为某型号柴油机的国产化改进提高提供了可靠的技术保障。

  2. An analog modulation and demodulation method employing LVDT signal conditioner for fiber-optic interferometric sensors

    Zhou, Kejiang; Rao, Qi; Zhang, Minjie; Hu, Keke; Ruan, Yefeng


    An analog method to modulate and demodulate fiber-optic interferometric sensors employing a linear variable differential transformer signal conditioner to generate sine modulation wave and demodulate phase-modulated signal from the photodetector’s output is presented in this letter. No external lock-in amplifiers or digital components are used in this design. All the necessary components for signal processing are integrated in a single analog electronic microchip AD698, which reduces the system’s complexity significantly. After implementation on an interferometric fiber-optic gyroscope as an example, this method demonstrates a bias stability of 0.063 deg h-1 (i.e. 0.220 µrad).

  3. Analysis of Simultaneous Gas-Liquid Flow Through an Orifice and Its Application to Flow Metering Etude de l'écoulement simultané d'un mélange gaz-liquide à travers un orifice et son application à la mesure du débit

    Pascal H.


    Full Text Available The purpose of this article is to show a more accurate orifice equation for a two-phase flow, such a compressible mixture of gas and liquid. The orifice equation given here con be used for the measurement of a gas-liquid mixture of fine emulsions by the orificemeter method. From the thermodynamic point of view, an equation of state has been formulated which provides the relationship between the specific mass of the mixture and pressure, under conditions of adiabatic expansion. The results obtained enable the mass flow rates of gas and liquid ta be determined without separation of the phases, provided thot the gas liquid mass ratio is known. The critical pressure ratio corresponding ta sonic velocity is also determined. Cet article présente une relation plus précise pour l'écoulement d'un système à deux phases, tel qu'un mélange compressible gaz-liquide, à travers un diaphragme. Cette relation peut être utilisée pour des mesures de mélanges gaz-liquide très finement divisés, c'est-à-dire des émulsions ou brouillards, par la méthode du diaphragme en paroi mince. Du point de vue thermodynamique, on a formulé une équation d'état donnant la relation entre la masse spécifique du mélange et la pression dans des conditions d'expansion adiabatique. Les résultats obtenus per-mettent de déterminer le débit massique du gaz et du liquide, sans séparation des deux phases, à condition que le rapport de masse gaz-liquide soit connu. On détermine également le rapport de pression critique correspondantà la vitesse du son.

  4. Fused aortic valve without an elliptical-shaped systolic orifice in patients with severe aortic stenosis: cardiac computed tomography is useful for differentiation between bicuspid aortic valve with raphe and tricuspid aortic valve with commissural fusion

    Bak, So Hyeon; Ko, Sung Min [Konkuk University School of Medicine, Departments of Radiology, Konkuk University Medical Center, Seoul (Korea, Republic of); Song, Meong Gun; Shin, Je Kyoun; Chee, Hyun Kun; Kim, Jun Suk [Konkuk University School of Medicine, Departments of Thoracic Surgery, Konkuk University Medical Center, Seoul (Korea, Republic of)


    The objective is to determine cardiac computed tomography (CCT) features capable of differentiating between bicuspid aortic valve (BAV) and tricuspid aortic valve (TAV) in severe aortic stenosis (AS) patients with fused cusp and without elliptical-shaped systolic orifices. We retrospectively enrolled 53 patients who had severe AS with fused cusps and without an elliptical-shaped systolic orifice on CCT and who had undergone surgery. CCT features were analyzed using: (1) aortic valve findings including cusp size, cusp area, opening shape, midline calcification, fusion length, calcium volume score, and calcium grade; (2) diameters of ascending and descending aorta, and main pulmonary artery; and (3) rheumatic mitral valve findings. The variables were evaluated using univariate and multivariate logistic regression analyses. At surgery, 19 patients had BAV and 34 had TAV. CCT features including uneven cusp size, uneven cusp area, round-shaped systolic orifice, longer cusp fusion, and dilatation of ascending aorta were significantly associated with BAV (P < 0.05). In particular, fusion length (OR, 1.76; P = 0.001), uneven cusp area (OR, 10.46; P = 0.012), and midline calcification (OR, 0.08; P = 0.013) were strongly associated with BAV. CCT provides diagnostic clues that helps differentiate between BAV with raphe and TAV with commissural fusion in patients with severe AS. (orig.)

  5. 面向工程的气动带挡板节流孔音速流导计算方法%Engineering Calculation Method of Sonic Conductance for Pneumatic Orifice with Baffle

    刘文丰; 李刚炎; 杨凡


    目前,节流孔的音速流导计算一般只考虑与节流孔直径和长度的关系,没考虑节流孔挡板间隙.该文面向工程需要,针对气动带挡板节流孔音速流导计算问题,建立理论解析的数学模型,在Simulink中构建模型对音速流导进行计算,将计算得到的临界压力比数据,通过拟合的方式得到临界压力比计算式,进而得到带挡板节流孔的音速流导计算式.结合实验,确定音速流导计算式中的参数,将计算式简化成能在工程中使用的简易计算式;利用Fluent对带挡板节流孔模型进行仿真,通过仿真数据确定计算式的有效性与使用范围.%When sonic conductance of orifices is calculated, the diameter and length of the orifice are generally taken into accountbut the gap between the orifice and baffle at present. In this paper, based on the engineering needs, the mathematical model of the theoretical analy-sis and calculation model in Simulink is established for the calculation of the sonic conductance of pneumatic orifice with baffle.Based on the data of critical pressure ratio obtained by Simulink,a formula for calculating the critical pressure ratio is proposed. Then a formula for calculating the sonic conductance of orifice with baffle is proposed.The parameters in the calculation formula can be determined by the com-bination of experiment data. Therefor the formula can be simplified. The effectiveness and scope of the formula is verified by Fluent simula-tion data.

  6. Natural orifice transluminal endoscopic wedge hepatic resection with a water-jet hybrid knife in a non-survival porcine model

    Hong Shi; Sheng-Jun Jiang; Bin Li; Deng-Ke Fu; Pei Xin; Yong-Guang Wang


    AIM:To explore the feasibility of a water-jet hybrid knife to facilitate wedge hepatic resection using a natural orifice transluminal endoscopic surgery (NOTES) approach in a non-survival porcine model.METHODS:The Erbe Jet2 water-jet system allows a needleless,tissue-selective hydro-dissection with a preselected pressure.Using this system,wedge hepatic resection was performed through three natural routes (trans-anal,trans-vaginal and trans-umbilical) in three female pigs weighing 35 kg under general anesthesia.Entry into the peritoneal cavity was via a 15-mm incision using a hook knife.The targeted liver segment was marked by an APC probe,followed by wedge hepatic resection performed using a water-jet hybrid knife with the aid of a 4-mm transparent distance soft cap mounted onto the tip of the endoscope for holding up the desired plane.The exposed vascular and ductal structures were clipped with Endoclips.Hemostasis was applied to the bleeding cut edges of the liver parenchyma by electrocautery.After the procedure,the incision site was left open,and the animal was euthanized followed by necropsy.RESULTS:Using the Erbe Jet2 water-jet system,transanal and trans-vaginal wedge hepatic resection was successfully performed in two pigs without laparoscopic assistance.Trans-umbilical attempt failed due to an unstable operating platform.The incision for peritoneal entry took 1 min,and about 2 h was spent on excision of the liver tissue.The intra-operative blood loss ranged from 100 to 250 mL.Microscopically,the hydro-dissections were relatively precise and gentle,preserving most vessels.CONCLUSION:The Erbe Jet2 water-jet system can safely accomplish non-anatomic wedge hepatic resection in NOTES,which deserves further studies to shorten the dissection time.

  7. 高速涡轮泵动静压轴承新型长小孔节流器的试验建模%Experimental Modeling of New Long Orifice-type Restrictor of High Speed Turbine Hybrid Bearing

    杨培基; 袁小阳; 苏卫民; 欧阳武


    针对动静压轴承用小孔节流和毛细节流结构受应用空间尺寸限制问题,提出了一种尺寸介于两种典型节流器之间以满足涡轮泵空间要求的非典型长小孔节流结构,并对该结构进行了试验建模。通过分析动静压轴承小孔节流和毛细节流两种节流结构及流量数学模型,提出了一种与典型小孔节流器相近的长小孔节流器;给出了一种不直接利用整个轴承而利用孔板的试验建模可行方案,测量了节流孔长径比在4~10、压差1.5MPa~5.5MPa时力水润滑介质节流器的流量,得到了长小孔节流器的试验模型。研究结果表明:非典型结构的节流器需要试验建模,给出的非典型节流器流动规律近似于典型小孔模型。其节流模型大致属于紊流模型。%To solve the problem of space limit when orifice-type restrictor and capillary restrictor are applied to hy- brid bearings, this paper proposed a kind of non-typical long orifice-type restrictor to satisfy the space of turbine, the size of which is between other two kinds of typical restrictors, and the experimental model was established for this structure. Through analyzing the two types of restrictor structures and flow rate mode, this paper proposed a long small orifice-type restrictor similar to a typical orifice-type restrictor; and a feasible experimental modeling method was proposed, which took use of orifice plate but not the whole bearing. The flow rate of water film restrictor was measured under the aspect ratio of 4 - 10 and the pressure difference of 1.5 MPa - 5.5 MPa, and the experi- mental model of long orifice-type restrietor was achieved. The result shows that the restrictor of non-typical struc- tures should be modeled by experiment, and the flow discipline of non-typical restrictor given by this paper is famil- iar with typical orifice-type restrictor, of which the throttling model is almost a turbulence model.

  8. Efectividad clínica en el cuidado del orificio de salida del catéter peritoneal Clinical effectiveness in peritoneal catheter exit orifice care

    Antonia Gil Gil


    methods followed by the professionals who provide peritoneal catheter exit orifice care. We found that all of them had a sound basis and showed effective results. However, we asked ourselves which of them would be the most suitable to use in our unit. We opted to use the recommendations of scientific literature, including variables such as the specific needs of each patient, according to the environmental conditions of our community and the seasons of the year. The main objective of our study was to assess the validity and effectiveness of the protocol we had established for our patients. We carried out a descriptive and longitudinal epidemiological study lasting 2 years and 8 months. We calculated the incidence rate of catheter exit orifice infections and peritonitis per patient and for each of the years of the study (2008-2009-2010. We assessed the result by comparing them with the normality indices set by the Spanish Nephrology Association, in 2007. We broke down the total of infections according to seasons and calculated the percentage. We differentiated between infections caused by gram + and gram-bacteria. The results obtained showed that our protocol is valid and suitable for our patients, obtaining an overall peritonitis incidence rate of 0.72 for every 24 patient-months and an exit orifice infection rate of 0.61 patient-years, both of which are lower than the standard established by the Spanish Nephrology Association (2007. A higher incidence of infections was found in the summer period, specifically 46%. 1% chlorhexidine covers gram+ bacteria, gram- bacteria, spores, viruses and fungi but was found to be most effective with gram+ microorganisms.

  9. Flash-Boiling Atomization Characteristics of a Twin-Orifice Injector%Twin-orifice喷嘴的闪急沸腾喷雾特性

    具德浩; 乔信起; 肖进; 黄震


    利用多阈值图像处理法对Twin-orifice喷嘴的闪急沸腾喷雾特性进行研究。通过高速照相机分析在喷射开始、发展及结束时喷嘴的内部流场和雾化形态,研究膨胀室内部形核、气泡生长等如何影响雾化特性。较大的膨胀室为液化R134a的气化和沸腾提供了更多的空间和时间,其射流被高气/液质量比的两相流稀释。进口孔径小的喷嘴喷射流量小,膨胀室中蒸发潜热消耗快并导致腔内温度迅速下降,使其过热度较低,最终导致喷雾锥角小,液滴空间分布浓度低。%This work is to investigate the internal flow pattern and macroscopic spray characteristics of R134a(a rep-resentative of dimethyl ether)actuated through a Twin-orifice injector.The internal flow and spray images were re-corded at various times after the start of actuation using a visualization system consisting of a high speed digital cam-era and a metal halide lamp as the illumination source.Internal nucleation,bubble growth in the expansion chamber and external liquid atomization were observed simultaneously during the actuation.The transient continuous spray cone angles were measured in each case.The relationship between the internal boiling flow in the expansion chamber and external flash-boiling atomization was analyzed.Larger expansion chamber provided more residence time for boiling,and sprays were diluted by the mixture flow with higher gas/liquid mass fraction.

  10. Unlimited-Length Proctocolectomy Utilizing Sequential Intussusception and Pull-Through: Novel Clean Endolumenal NOTE-Assisted Technique With Transanal Natural Orifice Specimen Extraction Without Rectal Stump Opening in a Porcine Model.

    Kvasha, Anton; Khalifa, Muhammad; Biswas, Seema; Hamoud, Mohamad; Nordkin, Dmitri; Bramnik, Zakhar; Willenz, Udi; Farraj, Moaad; Waksman, Igor


    Transanal, hybrid natural orifice translumenal endoscopic surgery (NOTES) and NOTES-assisted natural orifice specimen extraction techniques hold promise as leaders in the field of natural orifice surgery. We report the feasibility of a novel NOTES assisted technique for unlimited length, clean, endolumenal proctocolectomy in a porcine model. This technique is a modification of a transanal intussusception and pull-through procedure recently published by our group. Rectal mobilization was achieved laparoscopically; this was followed by a transanal recto-rectal intussusception and pull-through (IPT). IPT was established in a stepwise fashion. First, the proximal margin of resection was attached laparoscopically to the shaft of the anvil of an end-to-end circular stapler with a ligature around the rectum. Second, this complex was pulled transanally to produce IPT. To achieve an unlimited-length proctocolectomy, the IPT step was repeated several times prior to bowel resection. This was facilitated by removing the ligature applied in the first step of this procedure. Once sequential IPT established the desired length of bowel to be resected, a second ligature was placed around the rectum approximating the proximal and distal resection margins. The specimen was resected and extracted by making a full-thickness incision through the 2 bowel walls. The anastomosis was achieved by deploying the stapler. The technique was found to be feasible. Peritoneal samples, collected after transanal specimen extraction, did not demonstrate bacterial growth. The minimally invasive nature of this evolving technique as well as its aseptic bowel manipulation has the potential to limit the complications associated with abdominal wall incision and surgical site infection.

  11. CFD Simulation and Experiment Research of Pipe Downstream With Orifice and Jet Impingement%孔板管道下游与射流冲击的CFD模拟及实验研究

    伊成龙; 张乐福


    In nuclear power plants, the How accelerated corrosion (FAC) occurs mainly in the secondary circuit, causing a significant impact on production practice. Straight pipes with an orifice and jet impingement were simulated by CFD at 250 ℃ and 273 ℃ , achieving flow patterns and shear force distributions on the surfaces of plates and in the internal of pipes, and identifying weak points caused by pipe thinning with an orifice and influence of jet impingement angle. The results show that the orifice diameter ratio in the straight pipe changing has little effect on the maximum point of shear stress. With smaller crashing angle, the greater the shear force is, and the stronger the mechanical action is.%在核电厂中,流动加速腐蚀主要发生在二回路,对生产实践造成很大影响.本次研究运用CFD在250℃和273℃下对带有孔板的直管以及射流冲击结构进行模拟研究,得出流场及剪切力在管道内和试样表面的分布,找出带孔板管道由于管壁减薄引起的薄弱环节及角度对射流冲击的影响.结果表明,直管孔板中管径比的变化对冲刷后剪切力最大点影响很小.冲刷角度越小,剪切力越大,机械作用越强.

  12. A study of lateral orifice jet of side-port longitudinal culvert filling and emptying system of ship lock%船闸闸墙廊道侧支孔射流研究

    黎贤访; 李云; 王勇


    Hydraulic model of lateral orifice jet is set up.Velocity distribution of the vertical axial surface of lateral orifice jet is measured with PIV system in different discharges under non-threshold and with-threshold conditions.The velocity distribution laws of lateral orifice jet are summarized and summed up through methods such as dividing flow field structure and extracting flow field cross section.Based on the experimental results, the on-way curves of maximum velocity of the cross-section and the relative height of maximum velocity point under non-threshold condition are protracted.The shapes of jet centerlines are drawn under with-threshold condition, and the approximate formula for calculating velocity along jet centerline is given.%建立侧支孔射流水力学物理模型,使用PIV测速仪测量了多组流量条件下侧支孔射流无槛工况和设槛工况孔前垂向中轴面的流速分布,通过划分流场结构和提取流场断面等方法,归纳和总结了侧支孔射流的流速分布规律.根据试验结果得出了无槛工况断面最大流速和断面最大流速点相对高度的沿程变化曲线,绘制了设槛工况槛后射流中心线,拟合得出了沿射流中心线的速度计算公式.

  13. Utilization of sharp edged orifice plates to control flows discharging to the atmosphere; Utilizacion de placas de orificio para restringir el flujo de vapor de ductos que descargan a la atmosfera

    Sanchez Upton, Pedro [Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad, Morelia, (Mexico)


    The inner pipe thermodynamic behavior of steam when discharged freely to the atmosphere at the sound speed is studied in this paper. In addition, the effect of sharp edged orifice plates into pipes is shown, when they are utilized as a flow control device. In one case, it is assumed an orifice plate located at few feet distance from the pipe entrance. In other case, it is supposed that the orifice plate is fixed at the exit plane of the pipe. In all cases, it is considered that the pipe length is short enough and the flow speed too high to despise the heat transfer to the surrounding. The results were obtained through the simultaneous solution of the three fundamental equations of fluid mechanics, as well as the water equation of state and a correlation to quantify the steam choking mass flow rate. The main conclusion of the study reflects that the acoustic celerity is reached at the pipe exit plane for any of the different pipe arrangements. The speed of sound into steam was of the order of 560 m/s. It is recommended to fix the orifice plate at the exit of the pipe, in order to reduce inner erosion due to the steam flow. [Espanol] Se estudia el comportamiento termodinamico del vapor en el interior de una tuberia que descarga libremente a la atmosfera, bajo condiciones de flujo critico, y se muestra el efecto que genera una placa de orificio en esta tuberia al ser utilizada como un restringente de flujo. Se tratan dos casos: en uno la placa de orificio se instala al inicio de la tuberia y en el segundo la placa se localiza en la parte final de la misma. En todos los casos se considera que la longitud del ducto es lo suficientemente corta y que la velocidad del flujo es alta, de tal suerte que la transferencia de calor al ambiente es despreciable. Las soluciones se obtienen al resolver simultaneamente las tres ecuaciones de conservacion, en conjunto con las ecuaciones auxiliares de estado y una ecuacion desarrollada para cuantificar a los flujos criticos de vapor

  14. 经自然腔道内镜手术的实验研究%Natural orifice transluminal endoscopic surgery on animal models

    王东; 郑永志; 吴仁培; 于恩达; 李兆申


    Objective To evaluate the safety and feasibility of natural orifice transluminal endoscopic surgery(NOTES)with current available techniques and endoscopic accessories.Methods Transgastric and transvaginal endoscopic abdominal cavity exploration were performed in 6 female pigs.A needle-knife and a ERCP scalpel were used to make an anterior gastric wall incision,and a dilating balloon to expand the passage,through which a therapeutic gastroscope was sent into the abdominal cavity to seek the target organ.Partial liver resection was performed in 2 cases.For incision closure,a clip was applied to the incision orifice or it was just given putting-aside therapy.One week later,the abdominal cavity was examined via vagina.Another week later,it was observed via other incision of the stomach.Four weeks after the operation,the pigs were sacrificed.Adhesion,injury to the organs and closure of the incision were evaluated.Results Transgastric procedures were performed 12 times and transvaginal procedures 6 times.Mean operation time via stomach was 33.4±10.9 min.and that via vagina WaS 10.1±2.5 min.All animals recovered and gained weight after the operation.The incision healed up with no obvious complications.Re-exploration showed adhesion of various degrees,no effusion,or injury to the organs were observed.Ketamine plus propofol achieved satisfactory anesthetic effect with no complications.One of the two animals which underwent liver partial resection died of disphragmatic muscle perforation.Hemarrhage occurred twice,both in the procedures via satisfied.One case developed abdominal abscess.Conclusion It Was feasible and safe to perform NOTES via transgastric and transvaginal approach to the abdominal cavity and liver resection.But development of NOTES specific instruments is essential to the procedure.%目的 初步探讨利用现有内镜器械经自然腔道内镜手术(NOTES)技术的可行性和安全性.方法 采用6头雌性猪模型.经胃时首先用针刀在管壁

  15. 孔板管道下游流动加速腐蚀速率数值模拟研究%Numerical Simulation Study of Flow Accelerated Corrosion in Downstream of Orifice Pipe

    彭翊; 韩睿璇; 陈耀东


    采用计算流体力学方法中的 k‐ε模型模拟了孔板管道下游管壁与流体间的传质系数分布,并利用Sanchez‐Caldera流动加速速率预测模型计算了孔板管道下游的流动加速腐蚀速率分布。结果表明,孔径比的减小会导致流动加速腐蚀敏感部位向孔板下游移动,入口流速的增大对孔板下游流动加速腐蚀敏感部位的位置无明显影响,pH值的增大能有效减小流动加速腐蚀速率。%The mass transfer coefficient distribution between the pipe wall and fluid was simulated by the k‐εmodel of computational fluid dynamic method .The distributions of flow accelerated corrosion (FAC) rate in downstream of orifice pipe were calculated by Sanchez‐Caldera model .T he results show that the sensitive position of FAC moves to downstream as decreasing orifice diameter ratio .However ,the increase of inlet velocity has no significant influence on sensitive position of FAC .The FAC rate can be effective‐ly reduced with increasing pH value .

  16. Noncircular orifice holes and advanced fabrication techniques for liquid rocket injectors. Phase 3: Analytical and cold-flow experimental evaluation of rectangular concentric tube injector elements for gas/liquid application. Phase 4: Analytical and experimental evaluation of noncircular injector elements for gas/liquid and liquid/liquid application

    Mchale, R. M.


    Results are presented of a cold-flow and hot-fire experimental study of the mixing and atomization characteristics of injector elements incorporating noncircular orifices. Both liquid/liquid and gas/liquid element types are discussed. Unlike doublet and triplet elements (circular orifices only) were investigated for the liquid/liquid case while concentric tube elements were investigated for the gas/liquid case. It is concluded that noncircular shape can be employed to significant advantage in injector design for liquid rocket engines.

  17. 孔板对载流管道中流致振动的影响分析%Study on Flow-Induced Vibration in Pipe Conveying Fluid with Orifice Plate

    刘向红; 罗毓珊; 王海军


    Taking the vibration and noise in Reactor Cavity and Spent Fuel Pit Cooling and Treatment pipe line in nuclear power plant as an example,based on the actual experimental engineering parameters,the experimental studies on fluctuating pressure excitation and pipe vibration resulted from flow disturbance induced by single local resistance element-orifice plate are conducted under the condition of the different flow rate and the same back pressure.The pipe flow field and pressure field is numerically simulated,especially the flow station of orifice plate.The simulation results and experimental data are compared and analyzed.The research results show that the energy spectrum increases with the increasing of the degree of throttle of orifice plate.As the increasing of flow rate and fluid disturbance,the spectrum breadth of pressure fluctuate increases without the disturbance of other excitation source.%以核电厂反应堆和乏燃料水池冷却和处理系统(PTR)传水管后管线所产生的振动问题为背景,根据工程实际参数,在不同流量、背压相同条件下,开展孔板单个局部阻力件诱发流体扰动产生的脉动压力激励和管道振动的试验.对管线的流场和压力场进行数值模拟,尤其是孔板的流动状况,并将模拟计算结果与试验结果进行分析比较.研究认为,随孔板节流度的增大,能谱增大.在没有其他激励源干扰的条件下,随流量增大,流体扰动增强,压力脉动的谱幅值增大.

  18. Endoluminal Palliative Treatment for Ureteral Orifice Invaded by Advanced Prostate Cancer%晚期前列腺癌侵犯输尿管口的腔内姑息性治疗15例临床分析

    柯坤彬; 官润云; 张建华; 陈骋; 李颢; 刘孝东; 申吉泓


    Objective To evaluate the clinical efficacy of transurethral resection of ureteral orifice invaded by advanced prostate cancer caused hydronephrosis. Methods A retrospective study was done in 15 patients who were diagnosed by advanced prostate cancer with invasion of ureteral orifice and treated by transurethral resection of ureteral orifice and maximal androgen blockade. 24 kidneys were diagnosed as hydronephrosis by ultrasound. Before the procedure, the average serum BUN was 13.2 mmol/L (8.9~28.5), the average serum Cr was 243.3 μmol/L (126.7~369.2), the average GFR evaluated by renal radionuclide imaging was 48.6 mL/min (31.1~66.2), and the upper urinary tract was obstructed in kidneys with hydronephrosis. Results All 15 patients underwent successfully transurethral resection of ureteral orifice and discharged after 4 days stay. The average procedure time was 65 min (50~100 min) and mean blood loss was 45 mL (30~65 mL) . The patients were followed up for 2~4 weeks. Hydronephrosis examined by ultrasound was ameliorated in 18 kidneys (75%) and not obviously changed in 6 kidneys (25%) in one week after procedure. Hydronephrosis examined by ultrasound was ameliorated in 20 kidneys (83.3%) and not obviously changed in 4 kidneys (16.7%) in two weeks after procedure. Within two weeks after procedure,the average serum BUN was 10.75 mmol/L (6.6~21.30 mmol/L), the average serum Cr was 187.3μmol/L (97.5~286.6 μmol/L), the average GFR evaluated by renal radionuclide imaging was 58.1 mL/min (37.8~79.2 mL/min),and upper urinary tract was unobstructed. Conclusion Upper urinary tract obstruction and renal function were ameliorated and improved in a short time by transurethral resection of ureteral orifice invaded by advanced prostate cancer which caused hydronephrosis.%目的:探讨晚期前列腺癌侵犯输尿管口导致肾积水行经尿道输尿管口等离子电切术的临床疗效.方法回顾性分析15例晚期前列腺癌侵犯输尿管口导致肾积水

  19. 上颌第二磨牙第四根管口的解剖定位方法研究%Study on anatomical location of maxillary second molars' fourth root canal orifices

    马惠萍; 李新春; 李峥


    Objective To discuss the anatomical location of maxillary second molars' fourth root canal orifices,which could improve the efficacy of root canal treatment and the life quality of patients.Methods Pretreatments for 100 isolated maxillary second molar were taken,and the distances for required positions were measured by calipers.Then we observed these isolated teeth with Japan' s Olympus ENT endoscope system and shot each tooth' s pulp floor.After that the photographs were saved in computer and measured.Results Totally 100 maxillary second molars had the fourth root canal in a probability of 39%,the probabi of occurrence in the palatal root double was 1%.The position of the fourth root canal was found on the lingual side nesiobuccal root canal and in the mesial side of the line between the palatal root tube center point and the center point of the mesiobuccal root canal orifice.Conclusions Making it clear of the specific position of maxillary second molars' fourth root canal orifices could reduce the failure rate of root canal treatment;Thereby improve the treatment satisfaction of patients,which is worth for clinical practice.%目的 本文将探讨上颌第二磨牙第四根管口解剖定位,从而提高临床根管治疗效果,最终提高牙病患者生活质量.方法 将100颗上颌第二磨牙标本进行预处理后,使用游标卡尺对标本各不同部位距离进行测定,之后使用日本Olympus耳鼻喉内窥镜系统对标本进行观察,并垂直于标本髓室底拍摄各髓室底图,将所拍摄图像存入计算机内进行角度测量.结果 100颗上颌第二磨牙标本发生第四根管口几率为39.00%、发生腭侧根双管几率为1.00%;上颌第二磨牙第四根管口位于近中颊侧(MB)根管口舌侧,腭侧根管口中心点到近颊根管口中心点连线(MB-P)近中.结论 对患者进行上颌第二磨牙第四根管口明确定位,可提高患者治疗效果,降低患者根管治疗失败率,最终提高患者的

  20. Numerical simulation of minor geometry characteristics and small orifice water mist swirl injector%小几何特性小孔径细水雾离心喷嘴的数值模拟

    范文宏; 凌宗余; 富庆飞; 杨杰


    Due to the deficiency of the maximum discharge principle with regard to the design of the minor geometry characteristics and small orifice water mist swirl injector, a numerical investigation on it was performed by simulating the inner flow field of two phase flow injector using the mixture model in Fluent, from which the flow rate and spray angel a were obtained and compared with the experimental data and the theoretical calculation results. The gas-liquid phase distribution, axial velocity and tangential velocity, pressure distribution in the injector were also investigated. The discrepancy between the investigation and the traditional design theory was discussed and the mechanism was concluded. The viscosity of liquid and the friction of wall were taken into account which made the simulation can describe the inner flow field of injector accurately and the numerical simulation provides a reference for the design of minor geometry characteristics and small orifice water mist swirl injector.%针对最大流量原理法在设计小几何特性小孔径细水雾离心喷嘴方面的不足,采用Fluent软件中的多相流混合模型,模拟了包含蒸气和水两相的喷嘴内部流动,得到了流量、喷雾锥角等宏观参数,并和实验测量数据以及理论计算值进行了对比,分析了不同结果产生的原因;同时,还对喷嘴内的气液两相体积分数、轴向与切向速度、压力分布等流场特性参数进行了分析,着重论述了与理论模型之间的差异以及相应的机理.数值模拟方法考虑了液体的粘性和壁面摩擦力等因素,较好地反映了喷嘴内部的流场特性,为小几何特性小孔径细水雾离心喷嘴的设计提供了借鉴.

  1. Perioperative nursing of 10 patients undergoing pure natural orifice translumenal endoscopic surgery transvaginal nephrectomy%10例经阴道纯自然腔道内镜肾切除术的围手术期护理

    李莉莉; 邹晓峰; 蒙美英; 刘兰英; 曾小英; 王萍; 肖芳真; 阳贻梅; 黄郁兰; 张国玺


    对10例经阴道纯自然腔道内镜手术(NOTES)肾切除术进行了围手术期护理.护理要点为:①术前进行心理护理,使患者在最佳的心理状态下接受手术;②做好充分的术前准备,如肠道准备、阴道准备、皮肤准备等;③术后加强呼吸道管理,密切观察阴道出血情况,注意各引流管护理,防止腹胀或肠梗阻的发生;④加强术后舒适护理,保障患者良好恢复;做好出院宣教,加强术后随访.本组10例均痊愈出院.%This paper summarizes the perioperative nursing of 10 patients undergoing pure natural orifice translumenal endoscopic surgery(NOTES) transvaginal nephrectomy. The key points in nursing were preoperative psychological nursing; sufficient preopera-tive preparations, such as bowel preparation, vaginal preparation and skin preparation; close observation of vaginal bleeding,care of various drainage tubes, prevention of abdominal distension and intestinal obstruction, comfortable nursing, proper discharge education and follow-up services. All the patients were discharged.

  2. Clinical and Pathological Analysis of Dermatomyositis Combined with Cardiac Orifice Cancer%皮肌炎合并贲门癌的临床及病理特点分析

    康增军; 王芳; 李娜


    目的 分析皮肌炎(DM)合并贲门癌患者的临床及病理特点.方法 收集1例DM合并贲门癌患者的临床表现及开放式骨骼肌活体组织检查(活检)、组织化学染色病理与手术切除贲门病变组织的病理结果资料,进行回顾性分析.结果 本例为老年男性患者,临床表现为四肢近端肌肉伴吞咽肌无力2个月.查体:双上眼睑轻度水肿性紫红斑,咀嚼肌、吞咽肌肌力弱,髂腰肌、四肢近端肌肌力Ⅲ+级、远端肌肌力Ⅴ-级.实验室检查:红细胞沉降率46 mm/h、血肌酸激酶145 U/L、补体C4 0.44 g/L,均增高,C反应蛋白水平正常.肌电图:部分被检肌肉可见震颤、正相电位与波幅低、时限窄多相电位.活检骨骼肌组织化学染色光镜病理:可见典型束周肌纤维萎缩,肌内膜、肌束膜、血管周围炎性细胞浸润,未见坏死肌纤维.病理诊断为DM.电子纤维胃镜示:贲门灶状黏膜腺体重度不典型增生,可疑癌变.手术切除的贲门病变组织病理诊断为腺癌.结论 骨骼肌活检病理诊断是确诊DM的必备条件.中老年DM患者易并发恶性肿瘤,应积极行相关肿瘤筛查.%Objective To analyze clinical and pathological features of patients with dermatomyositis ( DM ) combined with cardiac orifice cancer. Methods Clinical data, skeletal muscle biopsy, pathological results of histochemistry staining and surgical resection of cardiac tissues of a patient with DM combined with cardiac orifice cancer were retrospectively analyzed. Results Clinical manifestations of the elderly male patient were limbs proximal muscle progressive weakness and mild dysphagia for more than 2 months. Clinical examination showed a heliotrope rash on the upper eyelids with mild oedema, the strength of masse-ter and swallowing muscle were weak, muscle strength score of iliopsoas and limbs proximal muscles were III + , of distal muscles were V -. Laboratory examination; erythrocyte sedimentation rate ( ESR ) 46 mm

  3. Reserved sutures for incision closure of transvesical natural orifice transluminal endoscopic surgery in pigs%预留线关闭猪经膀胱自然腔道内镜手术切口的初步尝试

    王辉清; 杨波; 肖亮; 牟燕清; 吴震杰; 徐斌; 王林辉; 许传亮; 孙颖浩


    Objective To close the incision of transvesical natural orifice transluminal endoscopic surgery (NOTES) with reserved sutures in pigs, and to assess the feasibility and safety of the technique, so as to lay a foundation for future clinical application. Methods Five female pigs were inserted with self-made Trocar into the bladder under general anesthesia. Guided by ureteroscope, the needle passed the top wall of the anterior bladder and reached the abdominal wall, with two suture ends reserved for closure, one at the abdominal wall and the other in the urethra(out of Trocar). After finishing the transvesical NOTES, we pulled the suture end at the abdominal wall to the bladder and knotted outside the Trocar; then we dragged the urethra suture end to make the knot on the abdominal wall locating on the lateral wall of bladder, and then the urethral suture was knotted in Trocar and the knot was pushed to the bladder wall using a knot pushing device; finally the bladder incision was closed. The closure of the bladder incision was observed and tested with water filling method. Results The first two cases failed due to the overweight and large size of the pigs, or because the bladder incision was to close to the bladder neck, or due to the poor quality of the suture. The procedures were successful in the following 3 pigs, with the operation time periods being 45 min, 30 min, and 25 min, and with satisfactory closure. Conclusion Reserved suture for incision closure of transvesical NOTES procedure is safe and feasible; the technique is easy to perform and needs no special surgery devices; and it deserves further study.%目的 尝试预留线关闭猪经膀胱自然腔道内镜手术(natural orifice transluminal endoscopic surgery,NOTES)切口,探讨其可行性、安全性,总结操作经验,为后续临床应用奠定基础.方法 雌香猪5只,全麻下置入自制膀胱鞘至膀胱.在输尿管镜的引导下,穿刺针穿刺膀胱顶前壁到腹下壁,预留2根关闭

  4. 节流阀口高速流场可视化测试方法研究%Research on the Visualization Testing Method of High-speed Flow Field in Throttle Orifice

    袁宝刚; 沈正湘; 曾荣辉


    Hydraulic valve is an essential part of hydraulic system.The flow field with high speed will produce cavitation which results in noise and vibration in throttle orifice.A method of visualization test was presented by which images and data could be collect-ed synchronously for high-speed flow field.By this way, not only the flow field in the hydraulic valve could be observed conveniently and intuitively, but also the noise, vibration and other information could be obtained.Research on the information collected by the method provides theoretical basis for designing hydraulic valve with low noise and low vibration.%液压阀作为液压系统的重要组成部分,其内部流体高速流动时会在节流阀口处产生空化现象,并由此产生噪声及振动。提出一种高速流场可视化测试方法,可以同步进行图像与数据采集,能方便、直观地对液压阀内部流场现象进行观测,同时获取噪声、振动等信息。对该测试方法获取的信息进行研究有助于为设计低噪声、低振动型液压阀提供理论依据。

  5. Calculation of Internal Flow Field in Different Nozzle Orifices of Diesel Engine at Needle Value Close Timing%针阀关闭时刻柴油机不同喷孔内流场的计算

    文华; 李潜; 徐颖韬


    A new algorithm consisting of two kinds of continuous mesh‐moving was proposed to make the needle close com‐pletely based on the open source software Open FOAM and the transient internal flow field in nozzles was numerically simulated by three steps .The simulation results coincided with the experimental results of S .Jollet .The effects of nozzle structure pa‐rameters on the flow field inside the hole were further studied .The results show that the bubble in residual fuel of nozzle occurs with the increase of nozzle diameter .The shorter nozzle orifice length leads to larger bubble volume inside residual fuel and closer distance of bubble with pressure chamber .Besides ,the decrease of K‐factor is beneficial to the formation of bubbles .%基于开源软件OpenFOAM定义两种连续的网格运动使针阀完全关闭,分三步数值模拟针阀关闭时刻喷孔内的瞬态流场,模拟结果与S .Jollet试验结果基本吻合。在此基础上研究喷孔结构参数对孔内流场的影响,计算结果表明,随着孔径的增大,喷孔内残余燃油内部有气泡形成;喷孔长度越短,喷孔内残余燃油内部的空气体积越大,形成的气泡越靠近压力室;K系数的减小有利于喷孔内气泡的产生。

  6. Simulation of a single stage orifice G-M type pulse tube cryocooler based on Sage%单级 G-M 型小孔脉管制冷机 Sage 建模

    刘东立; 甘智华


    G-M型脉管制冷机作为一项成熟的低温制冷技术,尚缺少公开的整机模拟分析方法。Sage软件包含压缩机、高低压切换阀和脉管制冷机冷头相关部件等模型。使用Sage软件建立了单级G-M型小孔脉管制冷机整机模型。将现有单级G-M型小孔脉管制冷机的实验设计参数作为输入参数,将Sage模型的计算结果与该制冷机实验结果进行对比,初步验证了模型的准确性,并重点计算分析高低压切换阀的孔径、时序对制冷机性能的影响。%The simulation of a whole G-M type pulse tube ( GMPT) cryocooler system is not reported before, although this kind of cryocooler is a mature technology .The Sage software has the models of com-pressors , switching valves and the parts to make up the cold head of the pulse tube cryocoolers .The whole system of a single stage orifice GMPT cryocooler was simulated based on Sage .The design paremeters of an existed cryocooler are substituted into the Sage model and then the calculation results are compared to the existed experimental results .The preliminary validation can be achieved by the comparation .The effects of diameters and the time ratio of the switching valves were analized based on the calculation results .

  7. 垂体窝上口形态学特点与垂体腺瘤生长关系的影像学研究%Imaging study of the relationship between morphological features of pituitary fossa superior orifice and growth pattern of pituitary adenomas

    韦拳堂; 漆松涛; 彭玉平; 陆云涛; 龙浩; 王剑新


    Objective To explore the relationship between morphological features of pituitary fossa superior orifice and growth pattern of pituitary adenomas. Methods One hundred patients with pituitary adenomas were selected as pituitary adenoma. One hundred healthy people were set as normal control group. Head CT scan was used to observe the anatomical features of the pituitary fossa superior orifice in healthy people and the sella turcica in patients with pituitary adenoma. The effect of morphological features of pituitary fossa superior orifice on the growth pattern of pituitary adenoma was analyzed. Results The slant angle of pituitary fossa superior orifice was 0.79°±l 1.69° in healthy people and -1.73°±12.42° in pituitary adenoma group. The angle in normal control group can be classified into three types, namely anteverted type, horizontal type and retroverted type. The angle between the longest diameter of tumor and pituitary fossa superior orifice was 91.18°±10.24° in pituitary adenoma patients. According to morphology of the sella turcica, the tumor was of sac type in 41 patients, wok type in 24, cylinder type in 13 and cribriform type in 22. Conclusions Pituitary adenoma grows upward basically perpendicularly to pituitary fossa superior orifice. The slant angle of pituitary fossa superior orifice determines the growth direction of pituitary adenoma toward suprasella.%目的 探讨垂体窝上口形态学特点与垂体腺瘤生长方式的关系.方法 收集100例垂体腺瘤病人作为垂体腺瘤组,正常对照组为100例健康人.运用CT扫描观察正常人垂体窝上口与垂体腺瘤病人蝶鞍的解剖特点,并分析垂体窝上口形态学特点对垂体腺瘤生长方式的影响.结果 正常对照组垂体窝上口倾斜角为(0.79°±11.69°),垂体腺瘤组为(-1.73°±12.42°).该夹角在正常人可分为前倾型、水平型、后仰型.肿瘤最长径与垂体窝上口之间的夹角为(91.18°±10.24°).垂体腺瘤根据蝶鞍

  8. Numerical Simulation of Spool Orifice Gas Jet for Novel High Pressure Electro-pneumatic Servo Valve%新型高压电-气伺服阀阀口气体射流数值研究

    杨钢; 高隆隆; 李宝仁


    提出一种新型音圈马达直接驱动滑阀式单级高压电-气伺服阀,针对其工作特点及阀芯受力情况,研究高压气体流经伺服阀阀口时气体射流角.在高压电-气伺服阀中阀口上下游压力比达到临界状态时,高压气体流经较小阀口时流速可达到声速,此时高压、高速气流产生的稳态气动力不容忽视,成为影响音圈马达直接驱动滑阀式单级高压电-气伺服阀控制精度及响应特性的重要干扰力.基于气体射流理论采用计算流体动力学方法对高压电-气伺服阀内部流场进行数值模拟,分析不同阀口开度对应的射流角大小,得出高压电-气伺服阀在不同阀口开度时射流角有较大差异,小阀口开度时射流角大于69°,当阀口开度达到设计最大开度时射流角接近69°,但伺服阀在精密控制系统中主要工作在零位附近,此时阀口开度较小,因此不同开度对应稳态气动力均采用射流角为69°的经典理论计算会产生较大误差.关于阀口射流角的数值研究可为高压气动伺服阀的研制及高压气动技术的发展提供一定的理论基础.%A novel voice coil motor direct-drive single stage high-pressure pneumatic servo valve is designed. And then the gas flow jet angle is investigated with numerical simulation, while the high-pressure gas flows through the valve orifice for the servo valve. At present, many studies about flow force are concentrated mainly on hydraulic valves, not on pneumatic valves. It is the reason that the gas flow force acting on the spool of low-pressure pneumatic valve is less, owing to small viscosity and density of low-pressure gas; besides the research on high-pressure pneumatic servo valve is seldom-reported so far. However, the velocity of gas flow is up to sonic when high-pressure gas flows through the micro servo valve orifice. And therefore, the steady gas flow force, generated by high pressure and high speed gas flow, cannot be

  9. Complication related to colostomy orifice: intestinal evisceration

    Valdemir José Alegre Salles


    Full Text Available Intestinal evisceration at the site of a stoma is a rare event, with high morbimortality. Its clinical manifestation often occurs between the sixth and seventh days after surgery. The risk factors most frequently related to evisceration are: increased intra-abdominal pressure, digestive tract cancer surgery, emergency surgery and stomas in the surgical incision. The authors report the case of a male patient, aged 62, suffering from adenocarcinoma of the rectum with obstructive acute abdomen, who underwent loop transversotomy for decompression. On the fourth day after surgery, he had a bronchospasm crisis, with evisceration of ileum and colon through the colostomic hole. The association of some triggering factors, such as emergency surgery, colorectal malignant neoplasm, increased intra-abdominal pressure and technical failure of colostomy were decisive in the development of this rare peri-colostomy complication.A evisceração intestinal desenvolvida no sítio de um estoma é um evento raro, tendo elevada morbimortalidade. Sua manifestação clínica ocorre frequentemente entre o sexto e o sétimo dias de pós-operatório. Os fatores de risco mais frequentemente relacionados à evisceração são: aumento da pressão intra-abdominal, câncer do aparelho digestório, cirurgia de urgência e estomias na incisão cirúrgica. Os autores relatam o caso de um paciente do sexo masculino, com 62 anos, portador de adenocarcinoma do reto médio com abdômen agudo obstrutivo, sendo submetido à transversostomia em alça, com finalidade descompressiva. No quarto dia de pós-operatório com crise de broncoespasmo, apresentou evisceração do cólon e íleo pelo orifício abdominal colostômico. A associação de alguns fatores desencadeantes, como a cirurgia de urgência, a doença neoplásica colorretal maligna, o aumento da pressão intra-abdominal e a falha técnica na confecção da colostomia, foram determinantes para o desenvolvimento desta rara complicação pericolostômica.

  10. The micro-orifice uniform deposit impactor-droplet freezing technique (MOUDI-DFT for measuring concentrations of ice nucleating particles as a function of size: improvements and initial validation

    R. H. Mason


    Full Text Available The micro-orifice uniform deposit impactor-droplet freezing technique (MOUDI-DFT combines particle collection by inertial impaction (via the MOUDI and a microscope-based immersion freezing apparatus (the DFT to measure atmospheric concentrations of ice nucleating particles (INPs as a function of size and temperature. In the first part of this study we improved upon this recently introduced technique. Using optical microscopy, we investigated the non-uniformity of MOUDI aerosol deposits at spatial resolutions of 1, 0.25 mm, and for some stages when necessary 0.10 mm. The results from these measurements show that at a spatial resolution of 1 mm and less, the concentration of particles along the MOUDI aerosol deposit can vary by an order of magnitude or more. Since the total area of a MOUDI aerosol deposit ranges from 425 to 605 mm2 and the area analyzed by the DFT is approximately 1.2 mm2, this non-uniformity needs to be taken into account when using the MOUDI-DFT to determine atmospheric concentrations of INPs. Measurements of the non-uniformity of the MOUDI aerosol deposits were used to select positions on the deposits that had relatively small variations in particle concentration and to build substrate holders for the different MOUDI stages. These substrate holders improve reproducibility by holding the substrate in the same location for each measurement and ensure that DFT analysis is only performed on substrate regions with relatively small variations in particle concentration. In addition, the deposit non-uniformity was used to determine correction factors that take the non-uniformity into account when determining atmospheric concentrations of INPs. In the second part of this study, the MOUDI-DFT utilizing the new substrate holders was compared to the continuous flow diffusion chamber (CFDC technique of Colorado State University. The intercomparison was done using INP concentrations found by the two instruments during ambient measurements of

  11. 利尿B超在诊断重复肾双输尿管合并输尿管开口异位中的应用%Diuresis Ultrasound Diagnosis of Duplex Kidney with Double Ureters and Ectopic Ureteral Orifice

    陈敏; 鲁功成; 邵明忠; 张齐钧; 张润清; 陈晓春; 曾甫清; 张秋艳; 吴玉珍


    Diuresis ultrasound was used to diagnose duplex kidney with double ureters and ectopic ureteral orifice in 8 cases.The result was satisfactory.In most cases the conventional ultrasound examination cann't show the normal ureter.Diuresis caused the ureter to be dilated(both upper and lower ureter).The duplex kidney and double ureters could be shown at same plane simultaneously.The ectopic dilated ureter did not enter into the bladder but extended along with the urethra behind the bladder.While the normal ureter showed as a slender and fine echo band,emerged into the trigone of bladder.The diagnosis of this abnormality in children sometimes may be very difficult.Diuresis ultrasound provides a reliable metod to detect this disease.The method is simple,easy to perform and also throws new light on ultrasound diagnosis.%采用利尿B超诊断重复肾双输尿管合并输尿管开口异位8例,结果令人满意.普通B超多不能显示正常输尿管.利尿可以使输尿管扩张(上、下半肾输尿管均扩张),操作者可以在同一切面上同时见到重复肾及双输尿管,而且可以在膀胱后方发现扩张的输尿管不进入膀胱而向尿道方向延伸.正常输尿管呈纤细狭长的回声带,开口于膀胱三角区.小儿重复肾双输尿管合并输尿管开口异位的诊断有时很困难.利尿B超为该病的诊断提供了确切的依据,并且简便易行,为超声诊断提供了新的方法与手段.

  12. The micro-orifice uniform deposit impactor-droplet freezing technique (MOUDI-DFT) for measuring concentrations of ice nucleating particles as a function of size: improvements and initial validation

    Mason, R. H.; Chou, C.; McCluskey, C. S.; Levin, E. J. T.; Schiller, C. L.; Hill, T. C. J.; Huffman, J. A.; DeMott, P. J.; Bertram, A. K.


    The micro-orifice uniform deposit impactor-droplet freezing technique (MOUDI-DFT) combines particle collection by inertial impaction (via the MOUDI) and a microscope-based immersion freezing apparatus (the DFT) to measure atmospheric concentrations of ice nucleating particles (INPs) as a function of size and temperature. In the first part of this study we improved upon this recently introduced technique. Using optical microscopy, we investigated the non-uniformity of MOUDI aerosol deposits at spatial resolutions of 1, 0.25 mm, and for some stages when necessary 0.10 mm. The results from these measurements show that at a spatial resolution of 1 mm and less, the concentration of particles along the MOUDI aerosol deposits can vary by an order of magnitude or more. Since the total area of a MOUDI aerosol deposit ranges from 425 to 605 mm2 and the area analyzed by the DFT is approximately 1.2 mm2, this non-uniformity needs to be taken into account when using the MOUDI-DFT to determine atmospheric concentrations of INPs. Measurements of the non-uniformity of the MOUDI aerosol deposits were used to select positions on the deposits that had relatively small variations in particle concentration and to build substrate holders for the different MOUDI stages. These substrate holders improve reproducibility by holding the substrate in the same location for each measurement and ensure that DFT analysis is only performed on substrate regions with relatively small variations in particle concentration. In addition, the deposit non-uniformity was used to determine correction factors that take the non-uniformity into account when determining atmospheric concentrations of INPs. In the second part of this study, the MOUDI-DFT utilizing the new substrate holders was compared to the continuous flow diffusion chamber (CFDC) technique of Colorado State University. The intercomparison was done using INP concentrations found by the two instruments during ambient measurements of continental

  13. 异形孔隔板换热器壳侧传热与阻力性能的试验研究%Experimental study on shell-side heat transfer and flow resistance performance of heat exchangers with non-round orifice baffles

    盛艳军; 陈亚平; 操瑞兵; 董聪; 吴嘉峰


    The shell-side heat transfer and flow resistance performances of shell-and-tube heat exchangers with different non-round orifice baffle (square, fillet triangle, mesh and cinquefoil) and a segment baffle heat exchanger were tested. A common heat exchanger shell and replaceable tube bundles were adopted. The shell-side axial Reynolds number is used as the independent variable versus the characteristics of the testing heat exchangers. The integrated index of the shell-side Nusselt number over the axial Euler number is suggested for evaluation of the heat exchanger performance of different schemes. The experimental results show that the mesh orifice baffle has the equivalent heat transfer coefficient as the segment baffle. But the pressure drop of the former is lower, and in the experimental range the average value of the relative comprehensive performance of the shell-side Nusselt number over the axial Euler number is about 1. 274. Both the heat transfer coefficients and the comprehensive performance indexes of the heat exchangers with cinquefoil, fillet triangle and square orifice are lower than those of the segment baffle heat exchanger. The heat transfer performance of the heat exchangers with non-round orifice baffles is related to the shape and the number of the orifices, and the flow resistance is related to the total area and hydraulic perimeter of the flow orifices.%对正方形孔、三角圆头孔、网状孔、六角梅花孔隔板换热器及弓形折流板换热器的传热性能和压降性能进行了测试试验.试验件采用公用管壳可拆卸芯体管束结构,针对其特点将壳侧轴向雷诺数作为自变量,利用单位壳侧轴向欧拉数的壳侧努谢尔特数指标来反映换热器的综合性能.试验结果表明,网状孔隔板换热器的壳侧换热系数与弓形折流板换热器相当,但该换热器的压降较低,在试验范围内综合性能指标的相对值为1.274;六角梅花孔、三角圆头孔和正方形孔隔

  14. Electric Discharge Caused by Expanding Armatures in Flux Compression Generators


    FMG seed source were initiated Fig. 2a, detonating the HE charge loaded in the central hole of the Nd2Fe14B hard ferromagnetic ring. There is a...bright light clearly visible in the central hole of Nd2Fe14B ferromagnet Fig. 2b due to the initiation of the HE charge. The HE charge was contact with the Nd2Fe14B ; as such, the transverse shock wave from the ex- plosive detonation propagated through the body of the Nd2Fe14B ring from

  15. A contoured gap coaxial plasma gun with injected plasma armature

    Witherspoon, F. Douglas; Case, Andrew; Messer, Sarah J.; Bomgardner, Richard; Phillips, Michael W.; Brockington, Samuel; Elton, Raymond


    A new coaxial plasma gun is described. The long term objective is to accelerate 100-200 μg of plasma with density above 1017 cm-3 to greater than 200 km/s with a Mach number above 10. Such high velocity dense plasma jets have a number of potential fusion applications, including plasma refueling, magnetized target fusion, injection of angular momentum into centrifugally confined mirrors, high energy density plasmas, and others. The approach uses symmetric injection of high density plasma into a coaxial electromagnetic accelerator having an annular gap geometry tailored to prevent formation of the blow-by instability. The injected plasma is generated by numerous (currently 32) radially oriented capillary discharges arranged uniformly around the circumference of the angled annular injection region of the accelerator. Magnetohydrodynamic modeling identified electrode profiles that can achieve the desired plasma jet parameters. The experimental hardware is described along with initial experimental results in which approximately 200 μg has been accelerated to 100 km/s in a half-scale prototype gun. Initial observations of 64 merging injector jets in a planar cylindrical testing array are presented. Density and velocity are presently limited by available peak current and injection sources. Steps to increase both the drive current and the injected plasma mass are described for next generation experiments.

  16. A contoured gap coaxial plasma gun with injected plasma armature.

    Witherspoon, F Douglas; Case, Andrew; Messer, Sarah J; Bomgardner, Richard; Phillips, Michael W; Brockington, Samuel; Elton, Raymond


    A new coaxial plasma gun is described. The long term objective is to accelerate 100-200 microg of plasma with density above 10(17) cm(-3) to greater than 200 km/s with a Mach number above 10. Such high velocity dense plasma jets have a number of potential fusion applications, including plasma refueling, magnetized target fusion, injection of angular momentum into centrifugally confined mirrors, high energy density plasmas, and others. The approach uses symmetric injection of high density plasma into a coaxial electromagnetic accelerator having an annular gap geometry tailored to prevent formation of the blow-by instability. The injected plasma is generated by numerous (currently 32) radially oriented capillary discharges arranged uniformly around the circumference of the angled annular injection region of the accelerator. Magnetohydrodynamic modeling identified electrode profiles that can achieve the desired plasma jet parameters. The experimental hardware is described along with initial experimental results in which approximately 200 microg has been accelerated to 100 km/s in a half-scale prototype gun. Initial observations of 64 merging injector jets in a planar cylindrical testing array are presented. Density and velocity are presently limited by available peak current and injection sources. Steps to increase both the drive current and the injected plasma mass are described for next generation experiments.

  17. A gene regulatory network armature for T-lymphocyte specification

    Fung, Elizabeth-sharon [Los Alamos National Laboratory


    Choice of a T-lymphoid fate by hematopoietic progenitor cells depends on sustained Notch-Delta signaling combined with tightly-regulated activities of multiple transcription factors. To dissect the regulatory network connections that mediate this process, we have used high-resolution analysis of regulatory gene expression trajectories from the beginning to the end of specification; tests of the short-term Notchdependence of these gene expression changes; and perturbation analyses of the effects of overexpression of two essential transcription factors, namely PU.l and GATA-3. Quantitative expression measurements of >50 transcription factor and marker genes have been used to derive the principal components of regulatory change through which T-cell precursors progress from primitive multipotency to T-lineage commitment. Distinct parts of the path reveal separate contributions of Notch signaling, GATA-3 activity, and downregulation of PU.l. Using BioTapestry, the results have been assembled into a draft gene regulatory network for the specification of T-cell precursors and the choice of T as opposed to myeloid dendritic or mast-cell fates. This network also accommodates effects of E proteins and mutual repression circuits of Gfil against Egr-2 and of TCF-l against PU.l as proposed elsewhere, but requires additional functions that remain unidentified. Distinctive features of this network structure include the intense dose-dependence of GATA-3 effects; the gene-specific modulation of PU.l activity based on Notch activity; the lack of direct opposition between PU.l and GATA-3; and the need for a distinct, late-acting repressive function or functions to extinguish stem and progenitor-derived regulatory gene expression.

  18. Superconductor Armature Winding for High Performance Electrical Machines


    141   8.6.2   Adhesive ...secured using dental floss. Figure 6.20. Ninety, reacted MgB2 triplets mounted to the outer surface of a G-10 cylinder in preparation for...fins and foams. First, we document preliminary work on the use of foams that are attached to fins with adhesives . Secondly, we describe work on the

  19. Hallucigenia's head and the pharyngeal armature of early ecdysozoans.

    Smith, Martin R; Caron, Jean-Bernard


    The molecularly defined clade Ecdysozoa comprises the panarthropods (Euarthropoda, Onychophora and Tardigrada) and the cycloneuralian worms (Nematoda, Nematomorpha, Priapulida, Loricifera and Kinorhyncha). These disparate phyla are united by their means of moulting, but otherwise share few morphological characters--none of which has a meaningful fossilization potential. As such, the early evolutionary history of the group as a whole is largely uncharted. Here we redescribe the 508-million-year-old stem-group onychophoran Hallucigenia sparsa from the mid-Cambrian Burgess Shale. We document an elongate head with a pair of simple eyes, a terminal buccal chamber containing a radial array of sclerotized elements, and a differentiated foregut that is lined with acicular teeth. The radial elements and pharyngeal teeth resemble the sclerotized circumoral elements and pharyngeal teeth expressed in tardigrades, stem-group euarthropods and cycloneuralian worms. Phylogenetic results indicate that equivalent structures characterized the ancestral panarthropod and, seemingly, the ancestral ecdysozoan, demonstrating the deep homology of panarthropod and cycloneuralian mouthparts, and providing an anatomical synapomorphy for the ecdysozoan supergroup.

  20. Hermatically sealed motor blower unit with stator inside hollow armature

    Donelian, Khatchik O.


    13. A hermetically sealed motor blower unit comprising, in combination, a sealed housing having a thrust plate mounted therein and having a re-entrant wall forming a central cavity in said housing, a rotor within said housing, said rotor comprising an impeller, a hollow shaft embracing said cavity and a thrust collar adapted to cooperate with said thrust plate to support the axial thrust of said shaft, one or more journal bearings within said housing for supporting the radial load of said shaft and electric motor means for rotating said rotor, said motor means comprising a motor-stator located within said cavity and adapted to cooperate through a portion of said re-entrant wall with a motor-rotor mounted within said hollow shaft, the portion of said re-entrant wall located between said motor-stator and said motor-rotor being made relatively thin to reduce electrical losses, the bearing surfaces of said thrust plate, thrust collar and journal bearings being in communication with the discharge of said impeller, whereby fluid pumped by said impeller can flow directly to said bearing surfaces to lubricate them.

  1. Nonlinear time-domain modeling of balanced-armature receivers

    Jensen, Joe; Agerkvist, Finn T.; Harte, James


    Nonlinear distortion added by the loudspeaker in a hearing aid lowers the signal-to-noise ratio and may degrade the hearing aid user's ability to understand speech. The balancedarmature- type loudspeakers, predominantly used in hearing aids, are inherently nonlinear devices, as any displacement o...

  2. 网状孔板纵向流换热器壳程流体流动及换热的三维数值模拟%Three-dimensional numerical simulation for shell side fluid flow and heat transfer characteristics in reticulated orifice-baffle longitudinal flow type heat exchangers

    王翠华; 张平; 吴剑华; 张先珍


    利用Fluent软件对网状孔板纵向流换热器壳程流体流动及换热进行了三维数值模拟,得到了壳程流体温度场、速度场及压力场等细观信息。根据模拟的结果,揭示了网状孔板强化壳程流体换热的机理,分析了壳程流体沿轴向流动及换热的性能,总结了近壁区流场及温度场的特点。%The fluid flow and heat transfer for shell side in reticulated orifice-baffle longitudinal flow type heat exchanger was simulated with Fluent software.The temperature field,velocity field,and pressure field in shell side were obtained.The enhancement mechanism of heat transfer due to the structure of reticulated orifice-baffle was discussed and the axial flow and heat transfer were analyzed for shell side according to the simulation results.Finally,an analysis of the flow field and temperature field close to the wall was given.

  3. Cirurgia por orifícios naturais transcolônica: acesso NOTES peri-retal (PNA para excisão mesoretal total Transcolonic natural orifice surgery: peri-rectal NOTES access (PNA for total mesorectal excision

    Ricardo Zorron


    Full Text Available OBJETIVOS: Cirurgia por orifícios naturais tem sido recentemente aplicada em series clínicas para cirurgia abdominal. Apesar de potenciais vantagens do acesso NOTES transcolônico para doenças colorretais, este ainda não havia sido utilizado clinicamente. O presente trabalho descreve a primeira aplicação bem-sucedida de NOTES transcolônico da literatura, em uma nova abordagem de excisão mesoretal total (TME para cancer de reto. MÉTODOS: Foi obtida aprovação de Comitê de Ética em Pesquisa para cirurgias por orifícios naturais, e o paciente assinou termo de consentimento informado. Em um paciente de 54 anos portador de adenocarcinoma de reto, o procedimento de retossigmoidectomia e linfadenectomia, com excisão mesoretal total foi realizada utilizando um acesso posterior transcolônico pouco acima da borda anal. A dissecção mesorretal foi conseguida utilizando um colonoscópio flexível e instrumentos endoscópicos, com assistência laparoscópica. O espécime foi retirado via transanal, e anastomose foi transorificial, com estoma proximal de proteção. RESULTADOS: O tempo operatório foi de 350 min, não ocorrendo complicações operatórias. A evolução pós-operatória foi favorável, e o paciente recebeu alta no sexto dia de pós-operatório com dieta plena. CONCLUSÃO: Este primeiro relato bem sucedido de cirurgia NOTES transcolônica traz potencialmente novas fronteiras de aplicações clínicas na cirurgia minimamente invasiva. O tratamento de doenças colorretais utilizando o novo acesso flexível PNA (Perirectal NOTES Access é uma promissora nova abordagem, paralelamente à laparoscopia e cirurgia aberta, para melhoria do tratamento dos pacientes.OBJECTIVES: Clinical natural orifice surgery has been applied for abdominal surgery in recent years. Despite potential advantages of transcolonic NOTES for colorectal diseases, it was since now not yet clinically applied. The study describes the first successful human

  4. 网状孔板纵向流换热器壳程流体流动及换热特性的数值模拟%Numerical Studies on Fluid Flow and Heat Transfer in the Shell Side of Reticulation Orifice-baffle Longitudinal Flow Type Heat Exchanger

    王翠华; 戴玉龙; 吴剑华; 战洪仁


    应用 CFD软件对网状孔板换热器壳程流体流动及换热特性进行了数值模拟研究,揭示了网状孔板强化传热的机理,分析了孔板间距及开孔率对其换热、压降性能的影响,推导出网状孔板纵向流换热器壳程换热与流动的准数关系式.结果表明,流体流过网状孔板产生射流及二次流现象,强化了壳程流体的传热;在Re=2300~6300范围内,网状孔板换热器比弓形折流板换热器的Nu数增大约50%,但压降比弓形折流板换热器高约2 5倍;在研究范围内,孔板间距减小、开孔率减小均能使壳程流体的Nu数及压降增大,且Re数越大,开孔率、折流板间距对Nu数及压降的影响越大;但随开孔率、折流板间距减小,流体压降增加的速度明显比Nu数快.%Numerical simulation of fluid flow and heat transfer in the shell side of reticulation orifice-baffle longitudinal flow type heat exchanger is carried out with CFD software. Heat transfer enhancement principle of the reticulation orifice-baffle is summarized, and the influences of space between baffles (L), and open area ratio (ψ) on its heat transfer and pressure drop Sp analyzed, and correlations are developed for the models. The results indicate that jet flow and second flow appear after fluid leaves the reticulation orifice-baffle, which enhance heat transfer of fluid in the shell side. Compared with plate baffle heat exchangers within Reynolds number Re=2 300-6 300, Nusselt number (Nu) of the reticulation orifice-baffle heat exchanger is about 50% higher than that of the plate baffle heat exchanger, while its shell side pressure drop is about 2.5 times higher than that of the plate baffle heat exchanger. In the range of study, both Nu and pressure drop rise with L or ψ decreasing, and the influences of L or ψ on Nu and △p increase with the increase of Re, but with L or ψ decreasing, increasing speed of Ap is obviously bigger than that of Nu.

  5. Falling Film Evaporator Throttle Orifice Calculation and its Adjustment to the Influence of Heating Temperature%降膜式蒸发器节流孔板的计算及其调整对加热温度的影响



    决定降膜式蒸发器温度高低的参数主要有两个:一个是一效蒸汽的压力。一个是冷凝器的使用效果。但在正常使用情况下,各效温度可在一定范围内进行微调,这种调整即为通过调换各效壳程中上下不凝性气体出口的节流孔板的孔径来实现,从而达到某效蒸发温度的需要。上下不凝性气体接口主要是为真空泵抽取不凝性气体而设置。节流孔板孔径小加热温度高,反之则低。仅以CNJM03-3200型三效降膜式蒸发器在茶粉生产中的应用为例进行阐述。%There are two factors determining the temperature of falling film evaporator: one is pressure of one-effect stream;the other is using effect of condenser. Under the ordinary circumstance,temperature of every effect can be slightly adjusted via adjusting throttle orifice aperture of up-and-down un-condensed gas outlet hole in shell sides to lower the temperature. Up-and-down un-condensed gas outlet hole is designed for vacuum extraction of the gas. The heating temperature is high when throttle orifice aperture is small,or vice versa. This paper uses Mode CNJM03-3200 three-effect falling film evaporator applied in the production of tea powder as an example to discuss the topics.

  6. The efficacy and safety of ureteral stenting after transurethral resection (TUR) of bladder tumors involving the ureteral orifice%累及输尿管口的膀胱肿瘤电切术后留置输尿管支架管的疗效及安全性

    李涛; 高祥勋; 吴翔; 彭俊铭; 吴进锋; 张弛; 余澄波; 魏永宝; 张延榕; 叶烈夫


    Objective To evaluate the efficacy and safety of ureteral stenting after transurethral resection ( TUR) of bladder tumors involving the ureteral orifice.Methods From March 2009 to November 2015,34 cases of non-muscle invasive bladder tumor including 28 male and 6 female aged from 26 to 79 years( mean 51 years) were treated by TUR.14 cases had single tumor and 20 had multiple tumors,and 29 were primary and 5 were recurrent.All the patients had tumors involving the ureteral orifice without preoperative hydronephrosis revealed by IVU or CTU examination.The tumors were resected into the deep muscle layer and the involved ureteral orifices were resected during the procedure,and after that a double-J ureteral stent was placed in 18 cases.All patients received one immediate intravesical instillation of 50mg epirubicin after TUR, and further scheme of adjuvant intravesical chemotherapy instillations were made according to the pathological diagnosis.Ureteral stents were removed 10-12 weeks after TUR,and cystoscopy and urinary tract ultrasound examinations were performed every 3 months for 1-2 years postoperatively. Results The operations were successful without complications.No serious adverse reaction occurred in immediate and further adjuvant intravesical chemotherapy.During the follow-up period of 3-71 months, no ureteral stricture, hydronephrosis or tumor recurrence in the upper urinary tract occurred in all the 18 patients with ureteral stent, and the resected ureteral orifices recovered well with normal appearance and ejecting urine.Hydronephrosis was observed in 3 of 16 patients without ureteral stent including 2 cases of nontumoral stenosis at the ureterovesical junction requiring ureteral reimplantation and 1 case of lower ureteral tumor on the involved side requiring nephroureterectomy and bladder cuff excision.No patient complained of symptoms secondary to vesicoureteral reflux or continuous unrelievable lower urinary tract symptoms.2 cases of bladder tumor

  7. Orifice diseases project - experience of the "Hospital das Clínicas" University of São Paulo Medical Center in day-hospital of anorectal disease Projeto doenças orificiais experiência do HCFMUSP em hospital-dia e doenças anorretais

    Sergio Carlos Nahas


    Full Text Available The treatment of malignant or benign colorectal pathologies that require more complex management are priorities in tertiary hospitals such as "Hospital das Clínicas" University of São Paulo Medical Center (HCFMUSP. Therefore, benign, uncomplicated orifice conditions are relegated to second place. The number of patients with hemorrhoids, perianal fistulas, fissures, condylomas and pilonidal cysts who seek treatment at the HFMUSP is very great, resulting in over-crowding in the outpatient clinics and a long waiting list for recommended surgical treatment (at times over 18 months. The authors describe the experience of the HCFMUSP over an eight-day period with day-hospital surgery in which 140 patients underwent surgery. Data was prospectively taken on the patients undergoing surgery for benign orifice pathologies including age, sex, diagnosis, surgery performed, immediate and late postoperative complications, and follow-up. 140 patients operated on over eight days were studied. 68 were males (48.75% with ages ranging from 25 to 62 (mean 35.2 yrs.. Hemorrhoids was the most frequent condition encountered (82 hemorrhoidectomies, 58.6%, followed by perineal fistula (28 fistula repairs, 20.0%. The most common complication was headache secondary to rachianesthesia occurring in 9 patients (6.4%. One patient (0.7% developed bleeding immediately PO that required reoperation. Mean follow-up was 104 days. Day-surgery characterized by quality care and low morbidity is feasible in tertiary public hospitals, permitting surgery for benign orifice pathologies on many patients within a short period of time.O tratamento das patologias colorretais malignas ou benignas, que necessitam tratamento com maior grau de complexidade são prioridades em hospitais terciários, como é o Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HCFMUSP, permanecendo assim as patologias orificiais benignas em um segundo plano. Todavia devido à sua

  8. Brushless DC Motors with Divided Armature and Hinged Armature%拼块式和铰链式无刷直流电动机




  9. Automatic classification of images with appendiceal orifice in colonoscopy videos.

    Cao, Yu; Liu, Danyu; Tavanapong, Wallapak; Wong, Johnny; Oh, JungHwan; de Groen, Piet C


    Colonoscopy is an endoscopic technique that allows a physician to inspect the inside of the human colon. In current practice, videos captured from colonoscopic procedures are not routinely stored for either manual or automated post-procedure analysis. In this paper, we introduce new algorithms for automated detection of the presence of the shape of the opening of the appendix in a colonoscopy video frame. The appearance of the appendix in colonoscopy videos indicates traversal of the colon, which is an important measurement for evaluating the quality of colonoscopic procedures. The proposed techniques are valuable for (1) establishment of an effective content-based retrieval system to facilitate endoscopic research and education; and (2) assessment and improvement of the procedural skills of endoscopists, both in training and practice.

  10. Usefulness of radionuclide angiocardiography in predicting stenotic mitral orifice area

    Burns, R.J.; Armitage, D.L.; Fountas, P.N.; Tremblay, P.C.; Druck, M.N.


    Fifteen patients with pure mitral stenosis (MS) underwent high-temporal-resolution radionuclide angiocardiography for calculation of the ratio of peak left ventricular (LV) filling rate divided by mean LV filling rate (filling ratio). Whereas LV filling normally occurs in 3 phases, in MS it is more uniform. Thus, in 13 patients the filling ratio was below the normal range of 2.21 to 2.88 (p less than 0.001). In 11 patients in atrial fibrillation, filling ratio divided by mean cardiac cycle length and by LV ejection fraction provided good correlation (r = 0.85) with modified Gorlin formula derived mitral area and excellent correlation with echocardiographic mitral area (r = 0.95). Significant MS can be detected using radionuclide angiocardiography to calculate filling ratio. In the absence of the confounding influence of atrial systole calculation of 0.14 (filling ratio divided by cardiac cycle length divided by LV ejection fraction) + 0.40 cm2 enables accurate prediction of mitral area (+/- 4%). Our data support the contention that the modified Gorlin formula, based on steady-state hemodynamics, provides less certain estimates of mitral area for patients with MS and atrial fibrillation, in whom echocardiography and radionuclide angiocardiography may be more accurate.

  11. Haptic Feedback in Natural Orifice Transluminal Endoscopic Surgery (NOTES)

    Do, Thanh Nho


    Flexible tendon sheath mechanism is commonly used in NOTES systems because it offers high flexibility, light weight, and easy transmission. Due to the size constraints and sterilization problems, traditional sensors like force/torque sensor are extremely difficult to place at the tool tips of surgical arms. In addition, nonlinear dynamic friction and backlash cause challenges to provide haptic feedback to the surgeons when the robotic arms are inside the patient's body. Hence, it is extremely difficult to provide the force information to haptic devices and subsequently to the surgeons. To deal with these problems, in this paper we propose a new approach of friction model in the tendon-sheath mechanism to provide the force at distal end of endoscopic system. In comparison with current approaches in the literature, the proposed model is able to provide force information at zero velocity and it is smooth. In addition, the model is independent configuration and able to capture friction force with any complex shea...

  12. Morphometry of the Myopectineal Orifice: Relevance in Prosthesis ...

    Hp 630 Dual Core

    COSECSA/ASEA Publication East and Central African Journal of Surgery . July/ August ... Laparoscopic techniques follow the principles of successful open ..... Felix EL, Michas cA, Gonzalez MH Jr. Laparoscopic hernioplasty, TAPP vs. TEP.

  13. Calculation in Orifice Plate of CEFR Condensate Water Recycling System

    TANG; Yi-min


    <正>In order to avoid condensation water pump occurring cavitation due to the flow is too small and affect the normal operation of pump when the startup or shutdown in the unit, low load or accident under empty load operation, recirculation loop should maintain a certain flow, to ensure that the shaft seal heater has enough cooling water, recirculation flow is not less than 20 t/h.

  14. International Conference on Natural Orifice Transluminal Endoscopic Surgery (NOTES)


    scopic versus open appendectomy: prospective randomized trial. Surg Laparosc Endosc Percutan Tech 9: 187-189 35. Paik PS. Towson JA. Anthone GJ. Ortega...Maxwell4 R. Seifeldin5 1 North Oakland Medical Centers. Surgery Wayne State University United States 2 Caritas Carney Hospital. Internal Medicine...Tufts University School of Medicine United States North Oakland Medical. General Surgery Wayne State University United States 4 North Oakland

  15. Assessment of intermediate-term outcomes of aortic valve replacement with enlargement of aortic annulus by changes in effective orifice area index%动态有效瓣口面积指数对扩大瓣环主动脉瓣置换术中期临床效果的评价

    朱亚彬; 朱兵; 杨岷; 石维平; 王宁夫; K.M.Cherian; 刘志勇


    Objectives To asses the intermediate-term clinical outcomes by changes in effective orifice area index (EOAI)in patients with small aortic annulus who received aortic valve replacement (AVR) enlargement of aortic annulus using two kinds of operations. Methods Thirty patients received AVR with enlargement of aortic annulus using Konno operation and Manougnian's operation were included in this study. Electrocardiogram (ECG), echocardiography (UCG), clinical symptom and changes of EOAI in Konno operation group and Manougnian's operation group were reviewed and compared with those in control patients received ordinary AVR during the same period. Results Twelve patients were in Konno operation group and 18 in Manougnian's operation group. At the prophase stage,case fatality rate of enlargement operation was 3.33%, incidence rate of arrhythmia was 76.3% and incidence rate of low cardiac output syndrome was 34.1%. They were followed up for 21 - 109 months with follow up rate of 100%. There was no significant difference in regression of left ventricular wall thickness, mass index and mean transvalvular gradients between Konno operation group and Manougnian's operation group after 3 years(P>0.05). There were no differences in 1-year survival rate and 3-year survival rate between enlargement operation group and ordinary operationro group(96.5% vs. 96.5%,P= 0.23; 86.2% vs. 89.65% ,P=0.14). The 3-year survival rates between Konno operation group and Manougnian's operation group had no significant difference (91.6% vs. 88.23% ,P>0.05). Difference in duration of operation and incidence of bundle-branch damage between enlargement operation group and ordinary operation group was significant (P<0.05). Values of EOAI in Konna group and Manougnian's group were higher than that in ordinary operation group, and it was higher in Konna group than in Manougnian's group. The differenes were significant(P<0.05). Incidence rate of dalated prosthesis-patient mismatch (DPPM) in Konno operation

  16. Clinical Study on XueShuanTong Combined with Citicoline Sodium Tablets for 46 Cases of Vertigo Induced by Vertebral-Basilar Artery Insufficiency of Blood Stasis Blocking the Orifices Pattern%血栓通联合胞磷胆碱钠片治疗瘀血阻窍型椎-基底动脉供血不足性眩晕46例临床研究

    谭文澜; 张永全; 陆晖


    Objective: To observe clinical effects of XueShuanTong and citicoline sodium tablets for vertigo induced by vertebral-basilar artery insufficiency (VBAI) of blood stasis blocking the orifices pattern. Method: All 92 patients were randomized into treatment group and control group, 46 cases each group. Treatment group received XueShuanTong and citicoline sodium tablets based on the routine treatment. One course was 15 days. Improvements of curative effects, TCM symptoms and blood flow rate on vertebral-basilar artery were observed in both groups after treating. Result: Clinical effects and improvement of TCM symptoms of treatment group were superior to that of control group(P<0.05), blood flow rate of VBAI was improved remarkably compared with control group(P<0.05). Conclusion: XueShuanTong and citicoline sodium tablets are effective in treating vertio caused by VBAI of blood stasis blocking the orifices pattern.%目的:观察血栓通联合胞磷胆碱钠片治疗瘀血阻窍型椎-基底动脉供血不足性眩晕的临床疗效.方法:将92例患者随机分为治疗组和对照组各46例,对照组常规治疗,治疗组在对照治疗的基础上加用血栓通、胞磷胆碱钠片,疗程15天,观察2组治疗后的疗效和中医症候、椎-基底动脉血流速度改善情况.结果:治疗组在临床疗效、中医证候改善等方面均优于对照组(P<0.05),椎-基底动脉血流速度较对照组明显提高(P<0.05).结论:血栓通联合胞磷胆碱钠片治疗瘀血阻窍型椎-基底动脉供血不足性眩晕疗效显著.

  17. Pure-transvaginal natural orifice transluminal endoscopic surgery (NOTES ovariohysterectomy in bitches: a preliminary feasibility study Ovário-histerectomia transvaginal pura por abordagem endoscópica transluminal por orifícios naturais (NOTES em cadelas: estudo preliminar de factibilidade da técnica

    Marco Augusto Machado Silva


    Full Text Available Natural orifice transluminal endoscopic surgery (NOTES is a relatively new surgical access for minimally invasive surgery, which is being widely studied in human medicine. However, few studies focusing on its applicability in the small animal practice have been performed so far. The aim of the current study was to evaluate the feasibility of pure-NOTES transvaginal ovariohysterectomy in bitches. Five bitches were evaluated. The abdomen was accessed through an 11mm trocar inserted through a vaginal incision. Using a rigid endoscope with working channel, the ovarian pedicles were coagulated and sectioned using bipolar diathermy. The uterine horn was pulled into the trocar and exteriorized along with the cannula. The uterine body and vessels were coagulated or ligated. The uterine stump was replaced into the abdominal cavity and the pneumoperitoneum drained. Pure-NOTES OHE was successfully accomplished in four out of five bitches. In the first try, it was converted to a hybrid-NOTES technique due to instrument failure. Mean surgical time was 52.1 (SD±11.5 minutes for the pure-NOTES technique. Pure-NOTES OHE is feasible in bitches, which may result in no major complications and excellent surgical recovery.Cirurgia endoscópica por orifícios naturais (NOTES constitui um acesso cirúrgico relativamente novo para abordagem minimamente invasiva, a qual vem sendo amplamente estudada na medicina humana. Porém, poucos estudos envolvendo sua aplicação na prática cirúrgica de pequenos animais foram realizados até o momento. O objetivo do presente estudo foi avaliar a factibilidade da ovário-histerectomia transvaginal por NOTES pura em cadelas. Cinco cadelas foram avaliadas. A cavidade abdominal foi acessada por um trocarte de 11mm introduzido por uma incisão vaginal. Empregando-se um endoscópio rígido com canal de trabalho, os pedículos ovarianos foram coagulados e seccionados usando-se diatermia bipolar. O corno uterino foi tracionado para o

  18. 经自然腔道内镜手术检查诊断结核性腹膜炎20例%Trans-gastric peritoneoscopy with technique of natural-orifice transluminal endoscopic surgery for diagnosis of tuberculosis peritonitis: a report of 20 cases

    朱惠明; 李迎雪; 王立生; 师瑞月; 黄勋; 王琴; 罗伟香


    目的 探讨经胃的经自然腔道内镜手术(NOTES)腹腔内镜检查对结核性腹膜炎的诊断价值.方法 回顾20例经胃NOTES腹腔内镜检查及病理活检确诊为结核性腹膜炎患者的相关临床资料,并进行性分析总结.结果 20例患者经胃NOETS腹腔内镜检查及病理活检后明确诊断为结核性腹膜炎.内镜检查结果为4型:(1)粟粒型:内镜表现为腹水、腹膜散在分布白色粟粒状结节;(2)粘连型:内镜表现腹膜增厚,腹膜与网膜、肠管之间存在不同程度的粘连;(3)干酪型:内镜表现壁层溃疡及淡黄色干酪样物质;(4)混合型:内镜表现为同时存在2种或3种类型.其他各项实验室及特殊检查的阳性例数分别为血红蛋白下降10例,红细胞沉降率增快16例,C反应蛋白升高13例,CA125升高18例,胸片异常8例,腹部彩超异常2例,腹部CT异常7例,结核菌素实验阳性9例,结肠镜检查阳性1例,20例结核抗体、腹水培养、腹水细菌学检查、胃镜检查均阴性.结论 经胃NOTES腹腔内镜检查及病理活检是确诊结核性腹膜炎非常有效的诊断方法.%Objective To investigate the diagnostic value of trans-gastric peritoneoscopy with technique of natural orifice transluminal endoscopic surgery(NOTES)for tuberculosis peritonitis.Methods Clinical data of 20 patients with tuberculosis peritonitis diagnosed by trans-gastric peritoneoscopy via NOTES were retrospectively analyzed.Results All diagnoses were confirmed by biopsy.The findings of peritoneoscopy were defined as miliary type with miliary nodes scattered in ascites and on peritoneum,adhesive type with thickening of peritoneum and adhesion between peritoneum and intestines,cheese-like type with parietal peritoneal ulcer and cheese-like substances,and mixed type with 2 or 3 of above mentioned types.Positive findings in other laboratory examinations were hemoglobin decrease in 10(50%)patients,blood sedimentation rate increase in 16(80

  19. A Laboratory Railgun for Terminal Ballistics and Arc Armature Research Studies


    barrel length was 1.5 m. The railgun js driven by a 4.5 MJ capacitor bank operating at 11 kV coupled to a 4.3 x 10- Henry pulse shaping coil inductor...utilized with light gas guns would be desirable. Tile electromagnetic railgun has the potential to meet these needs. However, sig- nificant innovation in the... railgun is driven by a 4.5 MJ capacitor bank operating at 11 kV coupled to a 4.3 x 10- 6 Henry pulse shaping coil inductor (time constant of 5 ms). The

  20. Servosystem with an undulatory reducing gear. [servomotor control by armature circuit

    Romashchenko, A. I.; Samoylenko, V. A.; Grishin, I. A.; Tatarchuk, Y. S.


    The development of a potentiometric servosystem is described that has a dc microservomotor, which is the built in drive of an undulatory reducing gear. The operation of the system and the structural design of the undulatory reducing gear are elaborated. Results are presented from analyzing some tests of various types of undulatory reducing gear generators.

  1. Servosystem with an undulatory reducing gear. [servomotor control by armature circuit

    Romashchenko, A. I.; Samoylenko, V. A.; Grishin, I. A.; Tatarchuk, Y. S.


    The development of a potentiometric servosystem is described that has a dc microservomotor, which is the built in drive of an undulatory reducing gear. The operation of the system and the structural design of the undulatory reducing gear are elaborated. Results are presented from analyzing some tests of various types of undulatory reducing gear generators.

  2. Two-port network analysis and modeling of a balanced armature receiver.

    Kim, Noori; Allen, Jont B


    Models for acoustic transducers, such as loudspeakers, mastoid bone-drivers, hearing-aid receivers, etc., are critical elements in many acoustic applications. Acoustic transducers employ two-port models to convert between acoustic and electromagnetic signals. This study analyzes a widely-used commercial hearing-aid receiver ED series, manufactured by Knowles Electronics, Inc. Electromagnetic transducer modeling must consider two key elements: a semi-inductor and a gyrator. The semi-inductor accounts for electromagnetic eddy-currents, the 'skin effect' of a conductor (Vanderkooy, 1989), while the gyrator (McMillan, 1946; Tellegen, 1948) accounts for the anti-reciprocity characteristic [Lenz's law (Hunt, 1954, p. 113)]. Aside from Hunt (1954), no publications we know of have included the gyrator element in their electromagnetic transducer models. The most prevalent method of transducer modeling evokes the mobility method, an ideal transformer instead of a gyrator followed by the dual of the mechanical circuit (Beranek, 1954). The mobility approach greatly complicates the analysis. The present study proposes a novel, simplified and rigorous receiver model. Hunt's two-port parameters, the electrical impedance Ze(s), acoustic impedance Za(s) and electro-acoustic transduction coefficient Ta(s), are calculated using ABCD and impedance matrix methods (Van Valkenburg, 1964). The results from electrical input impedance measurements Zin(s), which vary with given acoustical loads, are used in the calculation (Weece and Allen, 2010). The hearing-aid receiver transducer model is designed based on energy transformation flow [electric→ mechanic→ acoustic]. The model has been verified with electrical input impedance, diaphragm velocity in vacuo, and output pressure measurements. This receiver model is suitable for designing most electromagnetic transducers and it can ultimately improve the design of hearing-aid devices by providing a simplified yet accurate, physically motivated analysis. This article is part of a special issue entitled "MEMRO 2012".

  3. 耻骨上辅助经脐单孔腹腔镜技术在泌尿外科的应用价值(附57例报告)%Application of Suprapubic-Assisted Embryonic Natural Orifice Transumbilical Endoscopic Surgery in Urology(Report of 57 Cases)

    邹晓峰; 刘佛林; 徐辉; 杨军; 廖云峰; 钟辛; 江波; 张国玺; 袁源湖; 肖日海; 伍耿青; 王晓宁; 薛义军; 龙大治; 吴玉婷


    Objective: To describe the initial clinical experience of suprapubic-assisted embryonic natural orifice transumbilical endoscopic surgery (E-NOTES) in urology, and evaluate its safety, feasibility and efficacy. Methods : Fifty-seven consecutive patients including 42 males and 15 females, with a mean age of 46. 6 yeas (range 19 to 77), were subjected to suprapubic-assisted E-NOTES in our center. There were 5 adrenal tumors, 2 renal cysts, 2 renal tuberculosis, 8 renal carcinomas, 1 renal pelvic carcinoma, 14 non-functioning kidneys, 2 duplex kidneys, 4 ureteropelvic junction obstructions, 2 renal pelvic calculi, and 17 ureteral calculi in our study. Under general anesthesia, the patients were positioned in lateral decubitus with affected side elevated 70°. One 5 and 10 mm (or two 5 mm) trocars were inserted into the umbilical edge. A 10 or 5 mm trocar was inserted into abdominal cavity below the pubic hairline, through which a 10 mm 30° or 5 mm 0° iaparoscope was placed. The operation was same as that of standard laparoscopy. Some bigger specimens were removed after the incisions below the pubic hairline were enlarged. Results:The 57 procedures were all successfully performed. The mean operative time for adrenalec-tomy was 87 (range 73 to 130) mins, renal cyst excision 45 (range 35 to 55) mins, simple nephrectomy 115(range 95 to 173)mins,radical nephrectomy 95(range 80 to 158) mins,nephron-sparing surgery 96 mins, heminephroure-terectomy 150 (range 135 to 165) mins, nephroureterectomy 125 mins, pyeloplasty 149 (range 132 to 177) mins, pyelolithotomy or ureterolithotomy 83 (range 64 to 128) mins. The mean blood loss was 95 (range 50 to 300) ml. The patients resumed ambulation on postoperative day 1. 3 (range 1 to 2). Oral nutrition was resumed 2. 4 (range 2 to 3) d after surgery. The drainage tube was removed on postoperative day 2. 7 (range 2 to 4). Hospitalization duration was between 2 and 8 days with a mean postoperative stay of 6. 8 days. The mean follow

  4. Impact of transvaginal natural orifice transluminal endoscopic surgery-assisted laparoscopic nephrec-tomy on female sexual function and quality of life%经阴道自然腔道内镜手术辅助腹腔镜下肾切除术对女性性功能及生活质量影响的前瞻性研究

    邹晓峰; 龙大治; 徐辉; 杨军; 钟辛; 刘全亮; 吴玉婷; 张国玺; 袁源湖; 肖日海; 薛义军; 刘佛林; 伍耿青; 王晓宁


    Objective To investigate the impact of transvaginal natural orifice transluminal endo-scopic surgery(NOTES)-assisted laparoscopic nephrectomy on female sexual function and quality of life . Methods This was a prospective study on the change of female sexual function and quality of life of female patients who underwent transvaginal NOTES-assisted laparoscopic nephrectomy from May .2011 to Nov. 2012.A total of 42 cases were included in this study (28 of them with severe hydronephrosis , non-functio-ning kidney , 11 with pyelonephrosis , 1 with renal tuberculosis , 1 with duplex kidney complicated with hy-dronephrosis, and 1 with renal angiomyolipoma ).The mean age was 36.9±5.3 (26-45) years, and the mean body mass index was 21.7±2.6 (14.7 to 27.1) kg/m2.Twenty-four cases were operated on the left side, 18 cases on the right .The female sexual function and quality of life were assessed before and 4 months, 7 months and 1 year after surgery using the Female Sexual Function Index (FSFI) questionnaire and the MOS 36-item Short-Form Health Survey (SF-36), respectively. Results The mean FSFI of 42 cases preoperatively and 4 months, 7 months and 1 yr postoperatively were 27.74 ±4.34, 27.19 ±4.49, 28.54±4.23, and 28.68 ±4.19, respectively.There was no statistically significant difference among them (F=1.111, P=0.346).Compared with that of preoperation , the physical function, vitality, metal health, body pain, and general health of the patients were improved , but the role-physical, role-emotion and social function were not improved at postoperative month 4 and month 7 (P<0.05).Each item of SF-36 was im-proved after postoperative 1 year ( P<0.05) . Conclusions Transvaginal NOTES-assisted laparoscopic ne-phrectomy does not cause negative effect on the female sexual function .The quality of life can be improved after operation .The physical function is improved at early stage , and the psychological function as well .%目的:探讨经阴

  5. 透明帽吸引内镜夹闭合法在经自然腔道内镜外科手术切口闭合中的实验研究%Efficacy of endoscope clips with suction closure for the natural orifice transluminal endoscopic surgery access:a ex vivo porcine stomachs experiment

    杨勇致; 何德沛; 潘雪平; 景宇; 唐云淑; 罗阔; 曹宇; 宋晓雪; 吴世友; 梁爽


    目的:探索经自然腔道内镜外科手术(NOTES)切口大小的选择以及闭合方法。方法以41例离体猪胃为模型,用针状刀直接切开做入路切口。按切口大小及闭合方法分为4组,A组8例做大切口(长度1.2~2.0cm),直接用内镜夹闭合;B组10例做大切口(长度1.2~2.0cm),用透明帽吸引下内镜夹闭合切口;C组10例做小切口(长度小于或等于1.1cm),直接用内镜夹闭合;D组13例做小切口(长度小于或等于1.1 cm ),用透明帽吸引下内镜夹闭合切口。闭合完成后行注水测漏试验,比较结果。结果 A组1例闭合良好,7例失败;B组2例闭合良好,8例失败;C组2例闭合良好,8例失败,D组11例闭合良好,2例失败。采用χ2 Fisher确切概率法检验分析各组数据。A组与B组、C组比较,差异无统计学意义( P>0.05)。A组与D组比较,B组与D组比较,差异有统计学意义(P<0.05)。结论 NOTES切口以小于1 cm ,内镜刚好通过为佳,透明帽吸引内镜夹闭合法简单、实用、有效。%Objective To evaluate the feasibility and effectiveness of four closure techniques ,large incision with plastic distal at‐tachment and clip with suction ,1 .1 cm small incision with plastic distal attachment and clip with suction in natural orifice translu‐minal endoscopic surgery(NOTES) .Methods Forty‐one ex vivo porcine stomachs were involved in this research .According to the size of incision and different methods of incision closure ,all ex vivo porcine stomachs were divided into four groups .Group A in‐volved 8 ex vivo porcine stomachs ,their size of incision were 1 .2-2 .0 cm ,and their incisions were closured by a clip closure direct‐ly ;group B involved 10 ex vivo porcine stomachs ,their size of incision were 1 .2-2 .0 cm ,and their incisions were closed by plastic end attachment with suction and clip enclosure technique;group C involved 10

  6. 自然腔道内镜外科中扩张探条辅助胃壁穿透术的应用价值研究%Biliary passage dilator assisted percutaneous endoscopic gastostomy in natural orifice translumenal endoscopic surgery

    张修礼; Hyder Qurratulain; 唐平; 李闻; 孙刚; 杨竟; 张汝钢; 杨云生


    Objective To explore the feasibility and safety of the biliary passage dilator assisted percutaneous endoscopic gastostomy(PEG)in natural orifice translumenal endoscopic surgery(NOTES).Methods Eleven hybrid dogs were recruited to the study.One dog was used for pilot study of biliary passage dilator assisted PEG.The rest ten were divied into 2 groups randomly(5 per group), receiving conventional PEG and biliary passage dilator assisted PEG, respectively.The efficacy and safety of these 2 methods in NOTES were compared.Two weeks later, routine gastroscopy was performed to detect the healing of luminal incision and all animals were sacrificed to explore the possible complications in the abdominal cavity.Results With the assistance of the biliary passage dilator, successful transgastric access to the peritoneal cavity was achieved in the pilot study.Biliary passage dilator assisted PEG was completed in all the 5 dogs of the experimetal group, while tradional PEG succeded in only 4.The average transgastric puncture time in the biliary passage dilator assisted PEG(7.0 ± 1.7 min)was significantly shorter than that of conventional PEG (11.0 ± 3.2 min, P < 0.05).Nine dogs survived for 2 weeks postoperatively without loss of weight or peritonitis.Endoscopy showed transgastric puncture healed well.Autopsy revealed no gross adhering zone,bleeding, injury of adjacent organs or abcasses.Conclusion Compared with the conventional PEG, the biliary passage dilator assisted PEG shows the advantages of reduced difficulty and shoter time of puncture without any apparent complications.There is a good prospect of its application in NOTES.%目的 探讨扩张探条辅助PEG法胃壁穿透术在自然腔道内镜外科(NOTES)中的应用价值.方法 选择11只杂种犬,雌雄不限.首先对其中1只进行前期扩张探条辅助PEG法胃壁穿透术的可行性实验,在预实验成功后将剩余10只犬随机分成2组,分别进行传统PEG法胃壁穿透术(传统

  7. Prevention of infection by betadine irrigation of stomach during natural orifice transluminal endoscopic surgery%经胃自然腔道内镜手术中聚维酮碘溶液灌洗胃腔预防感染的临床研究

    郑永志; 王东; 李兆申; 孔祥毓; 龚燕芳; 陈丹磊; 杨丽; 吴仁培


    目的 评估聚维酮碘溶液灌洗胃腔在经胃自然腔道内镜手术(NOTES)感染预防中临床应用的安全性和有效性.方法 以2009年3月至2010年6月行经胃NOTES的9位患者为研究对象,手术在腹腔镜手术室进行.随灭菌胃镜置入灭菌外套管,留取胃腔内液5 ml(标本A);吸净胃液,聚维酮碘溶液(聚维酮碘50 g/L)200~ 300 ml喷洒灌洗,维持5 min后,留取灌洗液5 ml(标本B);经胃NOTES进行腹腔内手术操作后,留取腹腔抽取物5 ml(标本C).标本分别送检细菌培养及鉴定.术后置入胃管胃肠减压,抗炎、抑酸及补液支持处理,观察患者术后反应.结果 所有患者均完成经胃内镜腹腔内手术,5例有不同程度的腹腔镜辅助.标本A2例培养阴性,7例阳性,细菌以肠道细菌为主;菌落计数平均为35.6×103 CFU/ml.标本B和标本C细菌培养9例均为阴性.大部分患者术后无畏寒发热、恶心呕吐、明显腹胀腹痛等不适;术后血生化检查未见异常.术后1周复查胃镜,胃肠壁均无炎症、溃疡、出血等并发症,胃肠道切口止血夹闭合可,未见明显的渗漏等.所有患者术后随访6个月,均未出现感染等手术并发症.结论 临床使用聚维酮碘溶液灌洗胃腔预防经胃NOTES感染是安全可行和有效的,当然,进一步临床研究评估其安全性有效性仍是必需的.%Objective To study the safety and effect of betadine irrigation of stomach for preventing infection during natural orifice transluminal endoscopic surgery (NOTES).Methods The clinical data of 9 patients receiving transgastric NOTES at our center from March 2009 to June 2010 were reviewed.After general anesthesia,the stomachs were lavaged with 200 to 300 ml betadine.Then the endoscope was maneuvered in the peritoneal cavity after the creation of the gastronomy,and some procedures were performed with assistance of laparoscope.A total of 5 ml stomach fluid was collected before and after lavage,and 5 ml of peritoneal

  8. Transvaginal natural orifice transluminal endoscopic surgery (NOTES)-assisted laparoscopic partial nephrectomy%经阴道自然腔道内镜手术辅助腹腔镜下肾部分切除术的临床研究

    王晓宁; 张国玺; 邹晓峰; 袁源湖; 肖日海; 伍耿青; 薛义军; 刘佛林; 徐辉


    with conservative treatment.There were no other complications.Pathology indicated that all the tumors were clear cell renal cell carcinoma and all surgical margins were negative.During the follow-up of 3-14 mon,there was no recurrence.The median PSAQ score was 42 (39 to 48).All the patients completed the FSFI questionnaire.The median FSFI score was 27.7 (26.2 to 30.4).Conclusions Transvaginal NOTES-assisted laparoscopic partial nephrectomy is safe and feasible for small renal tumors with less pain,quick recovery and excellent cosmetic results.It does not cause negative effect on the female sexual function.%目的 总结经阴道自然腔道内镜手术(natural orifice transluminal endoscopic surgery,NOTES)辅助腹腔镜下肾部分切除术的经验,探讨该术式的临床应用价值. 方法 2013年8月至2014年8月收治6例肾肿瘤患者,均为已婚已育女性.年龄30~48岁,中位值37岁.肿瘤直径2.5~6.5 cm,中位值3.5 cm.均行经阴道NOTES辅助腹腔镜下肾部分切除术.全麻,截石位,患侧腰部垫高约60°.于两侧脐缘内置入工作套管及操作器械,自阴道后穹窿置入套管及5.4 mm 0°加长远端可弯曲(四方向)腹腔镜.游离肾脏并分别显露肾动、静脉.6例分别采用肾动脉完全阻断、肾段动脉阻断、肾动脉不阻断方法,距肿瘤边缘0.5 cm完整切除肿瘤,全层或分层连续缝合肾实质创面.标本装袋后自阴道后穹窿切口取出. 结果 本组6例均未中转开放手术或新增工作通道,其中5例手术顺利完成,1例肾上极肿瘤因开放肾动脉后肾实质创面持续出血改行根治性肾切除术.行肾动脉完全阻断3例,热缺血时间分别为20、25、28 min;肾段动脉阻断2例,阻断时间分别为35、40 min;肾动脉未阻断1例.手术时间110~190 min,中位值130 min.术中估计失血量100 ~ 400 ml,中位值150 ml.术后均无尿瘘发生;术后继发出血1例,保守治疗后痊愈.术后48 h视觉模拟疼痛评分1~3

  9. Dominant Role Of The Explosively Expanding Armature On The Initiation Of Electric Discharge In Magnetic Flux Compression Generators


    Nd2Fe14B high-energy hard ferromagnets. The FMG-LFCG pulsed power systems that we studied were completely autonomous, being powered exclusively by...were initiated [Fig. 3(A)] and the HE charge (0.7 g of C-4) loaded in central hole of the Nd2Fe14B hard ferromagnetic ring was detonated. A bright...light is clearly visible in the central hole of the Nd2Fe14B ferromagnet [Fig. 3(B)] due to the initiation of the HE charge. This process of

  10. Theoretic analysis of liquid film movement and its disintegration near the orifice of atomizer

    Zhou, Meng; Zhuang, Fengchen


    The movement of a conic liquid film in a restricted space is studied in this paper. The film is produced by a centrifugal nozzle and impinged on by a high-speed gas stream. Based on the theory of aerodynamics, some theoretical formulas for liquid film movement are established, a criterion of breaking up the moving liquid film is proposed and a formula for calculating the size of droplet formed by disintegration of the liquid film is presented. The calculation results can be used as a reference for atomizer design.

  11. Instrumentation for natural orifice translumenal endoscopic surgery and laparoendoscopic single-site surgery

    Candace F Granberg


    Conclusions : Significant progress has been made in developing new, multi-lumenal access ports and articulating or curved instruments to aid in triangulation necessary for certain urologic procedures. Magnetic anchoring guidance systems (MAGS have further enhanced the approach to LESS, with the potential for future application to NOTES. NOTES and LESS have future implications for the armamentarium of urologic surgeons, although much more research is necessary to further improve instrumentation and overcome the learning curve necessary for new technology.

  12. Congenital malformation of the vaginal orifice, imperforate vagina, in the common marmoset (Callithrix jacchus).

    Niimi, Kimie; Oguchi, Ayaka; Nishio, Kenji; Okano, Yasushi; Takahashi, Eiki


    The following is a report on a congenital vaginal malformation, imperforate vagina, in the common marmoset (Callithrix jacchus). This anomaly was observed for the first time in an adult female in our research colony. There was no uterine and vaginal aplasia or atresia in her grossly normal genital tract. The plasma progesterone concentration suggested that the ovarian cycle had ceased. However, this may not be related to a functional anomaly, but rather to suppressed ovulation resulting from subordination to cagemates considering the various stages of follicular development observed.

  13. Minimally invasive surgical technique integrating multiple procedures with large specimen extraction via inguinal hernia orifice

    Mani, Vishnu R.; Ahmed, Leaque


    While laparoscopic surgery can be performed using small skin incisions, any resected specimen must still be able to fit through these opening. For procedures, such as cholecystectomies and appendectomies, this is not usually a problem; however, for large specimens such as bowel or large tumors, this becomes problematic. Currently, the standard technique is to attempt piecemeal removal of the specimen or enlarge one of the laparoscopic incisions, effectively creating a mini laparotomy. Creatin...

  14. Multi-orifice active tilting-pad journal bearings—Harnessing of synergetic coupling effects

    Haugaard, Martin Asger; Santos, Ilmar


    The dynamic performance of tilting-pad journal bearings with controllable radial oil injection is theoretically investigated, exploring the synergetic effect between passive elastohydrodynamics and active radial lubricant injection. The flexible tilting-pads are modelled as linearly elastic using...... finite elements. To reduce computational work, a pseudo modal reduction is applied. Curves of dynamic bearing coefficients as well as the corresponding phase-magnitude plots are presented. Strong synergy between elastohydrodynamics and active control is observed, in particular for bearings with injection...

  15. Design of Orifice Injector%直流式喷注器设计




  16. Development of the platelet micro-orifice injector. [for liquid propellant rocket engines

    La Botz, R. J.


    For some time to come, liquid rocket engines will continue to provide the primary means of propulsion for space transportation. The injector represents a key to the optimization of engine and system performance. The present investigation is concerned with a unique injector design and fabrication process which has demonstrated performance capabilities beyond that achieved with more conventional approaches. This process, which is called the 'platelet process', makes it feasible to fabricate injectors with a pattern an order of magnitude finer than that obtainable by drilling. The fine pattern leads to an achievement of high combustion efficiencies. Platelet injectors have been identified as one of the significant technology advances contributing to the feasibility of advanced dual-fuel booster engines. Platelet injectors are employed in the Space Shuttle Orbit Maneuvering System (OMS) engines. Attention is given to injector design theory as it relates to pattern fineness, a description of platelet injectors, and test data obtained with three different platelet injectors.

  17. 喷注器盘的小孔加工%Orifice Machining Process of Injector Plate




  18. Mitigation of high-frequency pulsations, using Multi Bore Restriction Orifices

    Lier, L.J. van; Korst, H.J.C.


    In reciprocating fluid displacement systems, a trend toward high-speed machinery and application of stepless reverse-flow capacity control system is observed. Badly designed compression systems may cause excessive high-frequency noise and vibration levels, which are a risk from a structural integrit

  19. Low-loss energy storage flywheel

    Evans, H. E.; Studer, P. A.


    Magnetically-levitated, ironless-armature spokeless rotor is used. Ironless armature construction eliminates core losses due to hysteresis and eddy currents. Device combines features of homopolar salient poles and stationary ironless electronically commutated armature.

  20. ORNL Interim Progress Report on Static CIRFT Testing Curvature Data Update

    Wang, Jy-An John [ORNL; Wang, Hong [ORNL


    Since the CIRFT tests reported in NUREG-7198 were generated, a number of factors that influence the recorded curvature measurement data were identified. In 2016, a data reanalysis task was undertaken to implement the lessons learned. This letter report provides the revised results of previous CIRFT tests, after implementing the following data reanalysis procedures: (A) experimental data smoothing and LVDT reset, (B) LVDT probe contact and sensor spacing correction for curvature data, and (C) LVDT probe dynamic vibration adjustment procedure development.

  1. 机车牵引电机电枢轴承寿命研究%Locomotive traction motor armature bearing life study

    C.P.Lonsdale; 张秀珍


    为了确定Cyprina油脂润滑的机车牵引电机电枢轴承的大修里程,在开展广泛的轴承和油脂评价的同时,对方法和数据库作了回顾,并对目前生产厂家的做法和报告进行了探讨.对18台机车牵引电机电枢轴承及相关的油脂样品作了仔细研究,且对油脂和轴承零件进行了定性目检.分析了自电机大修后油脂的金属磨损污染、贯入度和随运行里程而变化的剩留油率.正常情况下装有Cyprina润滑脂的牵引电机电枢轴承其大修里程的上限为1 319 380 km.这是根据油脂中的剩留油率、主要机车生产厂家提供的数据、以及油脂中的铁磨损材料量和贯入度而得出的.

  2. Testing of traction motor armature in sulation%牵引电动机电枢绝缘测试的探讨




  3. Development, production and promotion of energy-saving and environmentally correct fixtures for private homes; Udvikling, produktion of markedsfoering af energi- og miljoerigtige armaturer til boligmarkedet

    Velk, A.; Munck, K. [Lysteknisk Selskab (Denmark)


    A design competition for environmentally correct and energy-saving fixtures for private homes was arranged in 2004. There were 88 entries and three were awarded with a prize. The purpose of the project was to produce and promote two or three proposals in a campaign for the use of environmentally correct and energy-saving fixtures. Three manufacturers of fixtures had given prior notice that they would produce the fixtures, but with certain conditions. Despite the many entries, the manufacturers assessed that none of them possessed the necessary qualities to commence product development. A group of designers were offered the possibility to find other manufacturers, but they did not succeed. (au)

  4. 不对称六相分数槽绕组磁势分析%Analysis of Armature Magnetometive Force on Anisomerous Hexaphase Fraction Slot Winding

    饶翔; 吴旭升; 任明炜


    针对不对称六相分数槽绕组合成磁势的对称性问题,采用槽号相位图法及单元电机理论,对三种典型的不对称六相绕组磁势进行分析.通过与对称三相及六相绕组比较,得出其合成磁势的性质与分数槽绕组每极每相槽数表达式的整数及小数部分取值有关,其变化规律是:在设计允许范围内,整数部分值选取的越大,其特性就越接近对称绕组;当整数部分值一定,小数部分取值越大时,其合成磁势对称性越好.%The magnetic motive force (MMF) of the asymmetrical hex winding motor with fraction slots is analyzed in the paper. In order to deal the resultant MMF symmetry problem of the motor which asymmetrical hexa-winding and fraction slots are installed on, the phase diagram and unit motor theory are adopted, and three typical asymmetrical hex-winding MMFs have been analyzed. Through the comparison to the symmetrical three phase windings, the results show that, the characteristics of the MMF are related with the integer and decimal parts of fraction slot numbers per-pole-per-phase. In the allowance, the more of the integer parts are, the better the asymmetrical hexa-windings approach. When the integer parts keep constant, the more of the decimal parts are, the better of the MMF symmetry get.

  5. As armaduras da cidade: o bonde e a construção de territorialidades em Curitiba The armatures of the city: trams and urban territorialities in Curitiba

    Caroline Brandão Andrusko


    Full Text Available A implantação de redes tecnológicas em determinadas regiões altera sua importância no conjunto urbano.Constituem-se territorialidades intraurbanas com um dinamismo socioeconômico mais relevante que oconjunto urbano. Neste artigo analisamos, em uma perspectiva histórica, como uma rede tecnológica, otransporte urbano hegemônico, cria espaços privilegiados na cidade, consolidando um desenho urbanoque, uma vez que o modal perde a relevância, torna-se um entrave para que novas atividades socioeconômicasse desenvolvam na região. Para a discussão apresentam-se as transformações morfológicas e socioeconômicas em uma região central de Curitiba, tendo como rede tecnológica enfocada os bondes.

  6. Factors affecting transmission of Wuchereria bancrofti by anopheline mosquitoes. 2. Damage to ingested microfilariae by mosquito foregut armatures and development of filarial larvae in mosquitoes.

    Bryan, J H; Southgate, B A


    Microfilariae (mf) of Wuchereria bancrofti from the midgut of 639 Anopheles gambiae, 557 An. arabiensis, 117 An. melas and 9 An. funestus were examined immediately after the mosquitoes had fed on carriers with different densities of mf. The percentages of mf damaged during ingestion were 57.1-60.0 in An. gambiae, 33.3-50.6 in An. arabiensis and 38.7-55.7 in An. melas. In each species the percentage of mf damaged was independent of mf density in the human host. A further 3657 An. gambiae, 2875 An. arabiensis, 347 An. melas and 32 An. funestus were examined 7 d or more after feeding on mf carriers. In An. gambiae and An. arabiensis, mean numbers of larvae per mosquito were strongly correlated to mf blood density, with similar regression slopes to those obtained from the regression of mf blood density on mean uptake of mf/mosquito. The ratio of mean numbers of larvae per mosquito to mean numbers of intact mf ingested per mosquito increased as the density of mf in the human host increased in An. gambiae and An. arabiensis, but decreased in An. melas as host mf density increased.

  7. Effects of an electromagnetic shield and armature teeth on the short-circuit performance of a direct drive superconducting generator for 10 MW wind turbines

    Liu, Dong; Polinder, Henk; Abrahamsen, Asger Bech


    To reduce the cost of energy of offshore wind energy conversion, large individual wind turbines of 10 MW or higher power levels are drawing more attention and expected to be desirable. Conventional wind generator systems would be rather large and costly if scaled up to 10 MW. Direct drive...... superconducting generators have been proposed to reduce the generator size, because the electrical machines with superconducting windings are capable of achieving a higher torque density. However, a superconducting machine is likely to produce an excessive torque during a short circuit because of its small...

  8. Rail and Armature Joule Heating of an Electromagnetic Rail Gun%电磁轨道炮导轨和电枢中的焦耳热分析

    李强; 范长增; 贾元智; 张连勇; 战再吉; 王文魁


    考虑了脉冲波形的影响,采用简化模型计算了自行设计的一种小型电磁轨道炮在单次发射后金属导轨和电枢中的焦耳热.结果表明铜导轨的热损耗是81.5 kJ,大约占输入总能量的20%,该热量可以使铜导轨表面的温度升高至260℃,远低于铜的熔点1 083℃.铝合金电枢中的焦耳热是991 J,该热量可以使电枢表面的温度升至270℃,表明电枢在发射过程中温度不会达到熔点(620℃).电磁轨道炮单次发射时其导轨和电枢的温升不会造成导轨和电枢的熔化.

  9. Technological study and characterization of injectors with micro-orifices for bi-liquid rockets engines; Etude technologique et caracterisation d'injecteurs a micro-orifices pour propulseurs biliquides

    Prevot, P. [Office National d' Etudes et de Recherches Aerospatiales (ONERA-DMAE/LP), 31 - Mauzac (France); Lecourt, R.; Foucaud, R.; D' Herbigny, F.X. [Office National d' Etudes et de Recherches Aerospatiales (ONERA-DMAE/MH), Centre du Fauga-Mauzac, 31 - Mauzac (France); Hervat, P. [Office National d' Etudes et de Recherches Aerospatiales (ONERA-DMTE/BET), Centre de Chatillon, 92 - Chatillon (France)


    Injectors for space rockets engines have been realised an tested at ONERA. Thanks to an original manufacturing technique, they allow one to get pulverization characteristics superior than those obtained with classic injectors. This improvement increases performances, allows a reduction of the size and mass of combustion chambers, while reducing manufacturing costs in the case of small series. These injectors are constituted by very thin plates fabricated by standard or chemical means. Individual plates are then assembled together by diffusion bond or brazing. This mode of fabrication allows one to conceive hydraulic circuits which would be impossible to realize with conventional metal machining. This technique, developed since the 70's in the United States by the AEROJET Company for the fabrication of platelets, complete combustion chambers and heat exchangers, has been adopted at ONERA for developing injectors at the request of CNES. An injector of this type, used at ONERA as a test tool on a very hot air generator, has given complete satisfaction. The industrial development of this technique will necessitate to achieve a technological step at the design level and to improve French capabilities in the diffusion bond process for materials others that titanium, such as stainless steel. (authors)

  10. Application of design rationale for a robotic system for single-incision laparoscopic surgery and natural orifice transluminal endoscopic surgery.

    Yao, Wei; Childs, Peter R N


    Current endoscopes and instruments are inadequate in some respects for complex intra-abdominal surgery because they are too flexible and cannot provide robust grasping and anatomic retraction. Minimal invasive surgery devices represent a sophisticated class of mechanical instruments making use of a range of mechanisms integrated into modular platforms that can be combined to undertake complex medical procedures. Although the machine elements concerned represent classic mechanical engineering devices, issues of miniaturization, surgical procedure compliance and location control conspire to present a design challenge. In order to capture, document and resolve the design requirements for this complex application, quality functional deployment has been applied in combination with design rationale, captured through issue-based information system mapping. This article reports the use of these tools to produce robot designs with improved dexterity and triangulation that are basic requirements in laparoscopy.


    LI Hai-feng; CHEN Hong-xun; MA Zheng; ZHOU Yi


    Based on the Navier-Stokes equations with considering the effect of the Coriolis force, the finite volume method was employed to discretize the governing equations, the SIMPLE method was adopted to solve the discretized equations, and the flow field in a barrel with an outlet at the center of the bottom was simulated. The numerical results agree well with the experimental data. From the Lagrangian, the relations among the acceleration, the Coriolis force and the viscosity force were analyzed. The results show that the Coriolis force is the major factor that causes the formation of the vortex. The flow fields in the flume under different incoming flow conditions were numerically simulated using the software Fluent. The numerical simulations show good agreement with the experiments for the shape and position of the vortex.

  12. Airspeed and orifice size affect spray droplet spectra from an aerial electrostatic nozzle for rotary-wing applications

    The aerial electrostatic spraying system patented by the USDA-ARS is a unique aerial application system which inductively charges spray droplets for the purpose of increasing deposition and efficacy. While this system has many potential benefits, no published data exits which describe how changes i...

  13. Airspeed and orifice size affect spray droplet spectrum from an aerial electrostatic nozzle for fixed-wing applications

    The aerial electrostatic spraying system patented by the USDA ARS is a unique aerial application system which inductively charges spray particles for the purpose of increasing deposition and efficacy. While this system has many potential benefits, very little is known about how changes in airspeed o...




    A number of authors have on the basis of experiments determined that pressure and gas density can have an influence on bubble formation size. Usually this influence is attributed to the gas momentum force, generated by gas flowing into the bubble during its formation. In this article the theoretical

  15. Sealed Orifice Laparoscopic or Endoscopic (SOLE) Surgery: technology and technique convergence for next-step colorectal surgery.

    Cahill, R A


    The new avenue of minimally invasive surgery, referred to as single-incision\\/access laparoscopy, is often presented as an alternative to standard multiport approaches, whereas in fact it is more usefully perceived as a complementary modality. The emergence of the technique can be of greater use both to patients and to the colorectal specialty if its principles can be merged into next-stage evolution by synergy with more conventional practice. In particular, rather than device specificity, what is needed is convergence of capability that can be applied by the same surgeon in differing scenarios depending on the individualized patient and disease characteristics. We detail here the global applicability of a simple access device construct that allows the provision of simple and complex single-port laparoscopy as well as contributing to multiport laparoscopic and transanal resections in a manner that is reliable, reproducible, ergonomical and economical.

  16. De Vega annuloplasty for functional tricupsid regurgitation: concept of tricuspid valve orifice index to optimize tricuspid valve annular reduction.

    Hwang, Ho Young; Chang, Hyoung Woo; Jeong, Dong Seop; Ahn, Hyuk


    We evaluated long-term results of De Vega annuloplasty measured by cylindrical sizers for functional tricuspid regurgitation (FTR) and analyzed the impact of measured annular size on the late recurrence of tricuspid valve regurgitation. Between 2001 and 2011, 177 patients (57.9±10.5 yr) underwent De Vega annuloplasty for FTR. Three cylindrical sizers (actual diameters of 29.5, 31.5, and 33.5 mm) were used to reproducibly reduce the tricuspid annulus. Long-term outcomes were evaluated and risk factor analyses for the recurrence of FTR ≥3+ were performed. Measured annular diameter indexed by patient's body surface area was included in the analyses as a possible risk factor. Operative mortality occurred in 8 patients (4.5%). Ten-year overall and cardiac death-free survivals were 80.5% and 90.8%, respectively. Five and 10-yr freedom rates from recurrent FTR were 96.5% and 93.1%, respectively. Cox proportional hazard model revealed that higher indexed annular size was the only risk factor for the recurrence of FTR (P=0.006). A minimal P value approach demonstrated that indexed annular diameter of 22.5 mm/m(2) was a cut-off value predicting the recurrence of FTR. De Vega annuloplasty for FTR results in low rates of recurrent FTR in the long-term. Tricuspid annulus should be reduced appropriately considering patients' body size to prevent recurrent FTR.

  17. Magnetic Resonance Imaging measurements of a water spray upstream and downstream of a spray nozzle exit orifice

    Mastikhin, Igor; Arbabi, Aidin; Bade, Kyle M.


    Sprays are dynamic collections of droplets dispersed in a gas, with many industrial and agricultural applications. Quantitative characterization is essential for understanding processes of spray formation and dynamics. There exists a wide range of measurement techniques to characterize sprays, from direct imaging to phase Doppler interferometry to X-rays, which provide detailed information on spray characteristics in the "far-nozzle" region (≫10 diameters of the nozzle). However, traditional methods are limited in their ability to characterize the "near-nozzle" region where the fluid may be inside the nozzle, optically dense, or incompletely atomized. Magnetic Resonance Imaging (MRI) presents potential as a non-invasive technique that is capable of measuring optically inaccessible fluid in a quantitative fashion. In this work, MRI measurements of the spray generated by ceramic flat-fan nozzles were performed. A wide range of flow speeds in the system (0.2 to >25 m/s) necessitated short encoding times. A 3D Conical SPRITE and motion-sensitized 3D Conical SPRITE were employed. The signal from water inside the nozzle was well-characterized, both via proton density and velocity measurements. The signal outside the nozzle, in the near-nozzle region, was detectable, corresponding to the expected flat-fan spray pattern up to 3 mm away. The results demonstrate the potential of MRI for measuring spray characteristics in areas inaccessible by other methods.

  18. 一种实用的印刷机高点闭牙机构开闭牙位置的确定方法%A Practical Approach for Open-closed Armature Position of the Press's High Spot Closed-armature Mechanism

    陈海生; 刘国栋



  19. 双电枢他励直流电动机两电枢回路并联稳定运行的理论分析%Theoretical Analysis of Steady Operation of Two Armatures Circuits Paralleled in the Two Armatures Separately Excited DC Motor




  20. Seismic wave generation systems and methods for cased wells

    Minto, James; Sorrells, Martin H; Owen, Thomas E.; Schroeder, Edgar C.


    A vibration source (10) includes an armature bar (12) having a major length dimension, and a driver (20A) positioned about the armature bar. The driver (20A) is movably coupled to the armature bar (12), and includes an electromagnet (40). During operation the electromagnet (40) is activated such that the driver (20A) moves with respect to the armature bar (12) and a vibratory signal is generated in the armature bar. A described method for generating a vibratory signal in an object includes positioning the vibration source (10) in an opening of the object, coupling the armature bar (12) to a surface of the object within the opening, and activating the electromagnet (40) of the driver (20A) such that the driver moves with respect to the armature bar (12) and a vibratory signal is generated in the armature bar and the object.

  1. 40 CFR 86.1308-84 - Dynamometer and engine equipment specifications.


    ....e., armature current, etc.) may be used for torque measurement provided that it can be shown that... flywheel torque due to the armature inertia during accelerations and decelerations in the test cycle....

  2. Impact of plasma noise on a direct thrust measurement system

    Pottinger, S. J.; Lamprou, D.; Knoll, A. K.; Lappas, V. J.


    In order to evaluate the accuracy and sensitivity of a pendulum-type thrust measurement system, a linear variable differential transformer (LVDT) and a laser optical displacement sensor have been used simultaneously to determine the displacement resulting from an applied thrust. The LVDT sensor uses an analog interface, whereas the laser sensor uses a digital interface to communicate the displacement readings to the data acquisition equipment. The data collected by both sensors show good agreement for static mass calibrations and validation with a cold gas thruster. However, the data obtained using the LVDT deviate significantly from that of the laser sensor when operating two varieties of plasma thrusters: a radio frequency (RF) driven plasma thruster, and a DC powered plasma thruster. Results establish that even with appropriate shielding and signal filtering the LVDT sensor is subject to plasma noise and radio frequency interactions which result in anomalous thrust readings. Experimental data show that the thrust determined using the LVDT system in a direct current plasma environment and a RF discharge is approximately a factor of three higher than the thrust values obtained using a laser sensor system for the operating conditions investigated. These findings are of significance to the electric propulsion community as LVDT sensors are often utilized in thrust measurement systems and accurate thrust measurement and the reproducibility of thrust data is key to analyzing thruster performance. Methods are proposed to evaluate system susceptibility to plasma noise and an effective filtering scheme presented for DC discharges.

  3. A Study on the Dynamic Performance for Hydraulically Damped Rubber Bushings with Multiple Inertia Tracks and Orifices: Parameter Identification and Modeling

    Chao-Feng Yang


    Full Text Available Hydraulically damped rubber bushings (HDBs are important for vehicle noise, vibration, and harshness (NVH performance as they are able to decay the vehicle’s oscillation induced by engine and road. The dynamic stiffness and loss angle of an HDB are crucial and it is significant to investigate the relations between the design parameters with the dynamic stiffness and loss angle. Therefore, the force-deflection relation of the HDB is measured statically and the dynamic stiffness and loss angle are measured dynamically and the test data are analyzed with a view to examine how the measurement results are influenced by the design parameters (the number of the fluid tracks. Compared with the results predicted by a nonlinear lumped parameter model whose parameters are extracted by a parameter identification technique, using the model, the effect of the main rubber and the fluid track on the dynamic stiffness and the loss angle is investigated. A unified analytical model of HDB is also developed with the purpose of predicting the static and dynamic characteristics, and the predictions are shown to be well correlated with the measurement data. The good correlation suggests the validity of the model and the parameter identification implementation.

  4. Drainage design and application of orifice leachate collection bags%引流管口渗液收集袋的设计及应用

    狄纪君; 郭卫东; 张惠洁


    Objective:To investigate the application results and improvement ostomy drainage spout puncture in-tractable exudate. Methods:All 84 cases of percutaneous drainage spout intractable effusion were randomly divided into two groups,42 patients using a modified ostomy in group A,42 patients using conventional methods dressing in group B,to observe the patients of two groups around the drainage spout irritant dermatitis occurred,healing,exudate drainage and collection results,and to compare the patientˊs comfort and dressing costs. Results:Improved Ostomy puncture drainage spout intractable collect exudate,help protect the skin puncture,drainage fluid nature observation, reducing the cost of dressing. Conclusion:Improved ostomy drainage ports for aseptic processing,with significant ad-vantages,combined with high quality care,can protect the skin puncture,which relieve suffering and economic burden of patients.%目的:探讨引流管口渗液收集袋对穿刺引流管口顽固性渗液的应用及效果。方法:对84例发生穿刺引流管口顽固性渗液的患者,随机分为两组,A 组42例患者使用引流管口渗液收集袋,B 组42例患者使用常规方法换药,观察两组患者引流管周围刺激性皮炎的发生、愈合,渗液的引流和收集效果,以及患者的舒适度和换药费用的比较。结果:应用引流管口渗液收集袋进行穿刺管口渗液的收集,利于保护穿刺口皮肤,观察引流液的性质,降低了换药成本。结论:引流管口渗液收集袋对引流口进行无菌处理,具有显著的优点,结合高质量的护理,对保护穿刺口皮肤,即减轻患者的痛苦及经济负担,又减轻了医务人员的工作量。


    邱利民; 陈国邦


    为了克服第三代脉管制冷机存在的制冷温度不稳定的缺陷,本文从提高脉管制冷效率,进一步降低制冷温度的角度,对有阀型小孔脉管制冷机进行了研究.通过理论计算和实验改进,有阀型单级脉管制冷机取得了34K的无负荷制冷温度,在80 K获得30 W以上的制冷功率,其制冷效率达到国外同类商品型有阀脉管制冷机的水平.

  6. 梨状隐窝定位食管入口的解剖学基础%Anatomic basis of piriform recess locating upper orifice of esophagus

    李寄云; 陈雪梅; 吴刚; 韩新巍


    目的:为临床介入放射置入食管内支架治疗高位食管良恶性病变提供解剖学基础.方法:经福尔马林固定的成人尸体标本共31具,沿正中矢状面做头颈部正中矢切面,以第7颈椎下缘水平切面,用1/50 mm游标卡尺和精密两脚规测量梨状隐窝下极与环状软骨板下缘之间的垂直距离,梨状隐窝下极与第5颈椎下缘的距离及其相对椎体位置关系,环状软骨板下缘与第5颈椎下缘的距离及其相对椎体位置关系.结果:(1)梨状隐窝下极与环状软骨板下缘的距离为(20.5±4.2)mm、梨状隐窝下极与第5颈椎下缘的距离为(10.7±9.3)mm、环状软骨板下缘与第5颈椎下缘的距离为(-3.5±11.7)mm.(2)环状软骨板下缘有62.5%位于颈6椎体水平.结论:以梨状隐窝下极定位食管入口的方法,是高位食管内支架置入可供选择的方法.

  7. Wet spinning of integrally skinned hollow fiber membranes by a modified dual-bath coagulation method using a triple orifice spinneret

    Li, S.-G.; Koops, G.H.; Mulder, M.H.V.; Boomgaard, van den A.; Smolders, C.A.


    Three main routes are known to prepare hollow fiber membranes; melt spinning, dry spinning and wet spinning (or dry/wet spinning). The latter is the most important technique for the preparation of industrial hollow fiber membranes. In this process the extruded polymer solution is immersed in a nonso

  8. Wet spinning of integrally skinned hollow fiber membranes by a modified dual-bath coagulation method using a triple orifice spinneret

    Li, S.G.; Li, S.-G.; Koops, G.H.; Mulder, M.H.V.; van den Boomgaard, Anthonie; Smolders, C.A.; Smolders, C.A.


    Three main routes are known to prepare hollow fiber membranes; melt spinning, dry spinning and wet spinning (or dry/wet spinning). The latter is the most important technique for the preparation of industrial hollow fiber membranes. In this process the extruded polymer solution is immersed in a nonso

  9. 自击式喷注器喷注孔测量方法研究%Measuring method for injecting orifice of self-impinging injector

    马如军; 李俊; 尚鹏宇; 李素琴



  10. Single-step, natural orifice transluminal endoscopic incision drainage of a pancreatic pseudocyst: can it be simpler, safer and more cost effective?

    Hyder, Qurratulain; Zahid, Mohammad Ahmad; Malik, Arif; Rasheed, Rakhshanda


    Conventional endotherapy for pancreatic pseudocyst involves placement of stents in the cyst cavity. We have successfully treated bulging pseudocyst in a 50 year old male by endoscopic incision drainage (EID), without insertion of endoprostheses. The presenting complaints in our patient were epigastric mass and postprandial vomiting. He had recently undergone open cholecystectomy following recovery from gallstone pancreatitis. EID was performed under general anaesthesia. Needle knife was advanced through the accessory channel of a flexible gastroscope. Cyst contents were evacuated by making 5 cm horizontal incision on the gastric indentation with dramatic relief in symptoms There is no cyst recurrence during follow up for over 3 years.

  11. 基于CFD的液压滑阀阀口处流场研究%Research of flow field in orifice of hydraulic spool valve based on CFD

    王辉; 潘生根


    The numerical simulation computation of flow field in a conical spool valve was carried,which was based on CFD approach. The simulation results of flow field distribution under fixed condition were analyzed,and the influence of opening and structural parameters of valve port on the flow field distribution in valve port were also analyzed and compared. The results show that the fluid flows complicatedly in valve port ,the flow field distribution is uneven in the axial and radial and affected by the opening and structural parameters of valve port; optimizing the structural parameters of valve port and changing the valve opening can improve the flow field distribution in valve port, prevent the cavitation and the vortex forming and developing, reduce pressure loss and energy consumption.%采用CFD方法对一种锥形阀口滑阀内流场进行了数值仿真计算,分析了在固定条件下其阀口处流场分布情况,并从阀口开度及结构参数等方面对影响阀口处流场分布进行了分析比较.研究结果表明:其阀口处流体流动情况复杂,流场在其轴向及径向分布不均衡,受阀口开度及结构参数等方面的影响;可通过优化阀口结构参数,改变阀口开度来改善阀口处流场分布状况,抑制气穴及旋涡的产生与发展,减小压降及能耗.

  12. Natural-orifice transluminal endoscopic surgery (NOTES) in Europe: summary of the working group reports of the Euro-NOTES meeting 2010

    Meining, A; Feussner, H; Swain, P


    collaboration and indications, robotics and platforms, and matters related to training and education. This review summarizes consensus statements of the working groups to give an overview of what has been achieved so far and what might be relevant for research related to NOTES in the near future....

  13. The Taguchi parameter design of armature core loss in permanent magnetism DC micro-motor%基于永磁直流微电动机电枢铁损的Taguchi参数设计

    文泽军; 刘德顺; 杨书仪; 汪程鹏



  14. Saving energy by optimized operation. Making use of saving potentials: Software solutions for design of pumps, armatures and pipelines; Mit dem richtigen Betriebspunkt Energie sparen. Sparpotenziale nutzen. Softwareloesungen zur Auslegung von Pumpen, Armaturen und Rohrleitungen

    Vogel, Jens-Uwe [VSX - VOGEL SOFTWARE GmbH, Dresden (Germany)


    Attempts to save energy included hydraulic optimization of aggregates and the development of new, high-efficiency electric drives and control systems. On the other hand, the saving potential of correct pipeline dimensioning in the planning phase and optimisation of operation is often underestimated. Correct design is a key element of efficient pump operation. Web-based planning tools can help. The new Spaix PipeCalc by VSX - VOGEL SOFTWARE is a calculation program for unbranched pipelines that was designed as an optimum supplement to pump design software.

  15. Stress Analysis of Armature with Different Structural Shapes Under Condition of Rail Gun Launcher System%不同结构形状电枢在电磁轨道发射状态下的应力分析

    白春艳; 张益男; 陈铁宁; 白象忠



  16. Electromagnetic Gun With Commutated Coils

    Elliott, David G.


    Proposed electromagnetic gun includes electromagnet coil, turns of which commutated in sequence along barrel. Electrical current fed to two armatures by brushes sliding on bus bars in barrel. Interaction between armature currents and magnetic field from coil produces force accelerating armature, which in turn, pushes on projectile. Commutation scheme chosen so magnetic field approximately coincides and moves with cylindrical region defined by armatures. Scheme has disadvantage of complexity, but in return, enables designer to increase driving magnetic field without increasing armature current. Attainable muzzle velocity increased substantially.

  17. Numerical simulation study on the effects of orifice structure on the shell-side heat transfer of cinquefoil orifice baffle heat exchanger%孔板结构对梅花形孔板换热器壳程传热影响的模拟研究

    罗朝嘉; 韩东; 牟春燕; 姚瑶; 何纬峰


    采用ANSYS CFX对梅花形孔板换热器壳程的流动和传热进行了数值模拟研究,通过分析壳程流场揭示了孔板换热器壳程强化换热机理,得到了3种不同开孔率的孔板换热器壳程平均努塞尔数Nu以及压降Δp随雷诺数变化的规律.结果表明:由于孔板处流道面积较小,流体产生射流效应并伴有二次流现象,在破坏流动边界层的同时增强了流体扰动,强化了换热;3种换热器的Nu和Δp都随雷诺数的增加而增大,开孔率越低换热器的换热性能越好,但壳程压降也越大;开孔率0.215的换热器综合性能参数(Nu/Δp)比开孔率0.173和0.130的换热器平均高28.8%和50.14%.

  18. An investigation of sliding electrical contact in rail guns and the development of grooved-rail liquid-metal interfaces

    Adamy, Mark T.


    The barrel life of a solid armature rail gun is a critical issue. Arcing along the barrel pathway at the interfaces between the armature and the rails produces severe damage. The ability to protect the rails and yet provide sufficient electrical contact to sustain arc-free high-current flow is desirable. This thesis investigates the use of liquid metal as an interface material between the sliding electrical contact surfaces of the armature and the barrel rails. Experiments were conducted with...

  19. Design of a Linear Variable Differential Transformer With High Rejection to External Interfering Magnetic Field

    Martino, M; Losito, R; Masi, A; Danisi, A


    The sensitivity of linear variable differential transformer (LVDT) position sensors to external slowly varying magnetic fields represents a critical issue when these sensors are installed close to high-current cables or electrical motors with significant fringe fields. The resulting position error can reach several hundreds of micrometers against a specified uncertainty normally below a few micrometers. In this paper, the design of a LVDT position sensor with high rejection to external constant or slowly varying magnetic fields is addressed by exploiting the finite element method (FEM) simulator FLUX. A shield, isolated from the sensor's magnetic circuit, has been considered to reduce the effect of magnetic fields on the secondary voltages of the LVDT. In addition, a dc current is used in order to polarize the magnetic circuit to reduce the sensitivity of the sensor to external interferences.

  20. Ureteral injuries during photoselective vaporization of the prostate

    Højgaard, M; Mikines, K.J.


    orifices are described, with hidden orifices, intravesical prostatic adenomas and prior prostatectomy as risk factors for laser-related injuries to ureteral orifices. A laser-coagulated ureteral orifice does not seem to regain patency spontaneously, so rapid nephrostomy and subsequent DJ stenting...

  1. 经尿道NOTES肾囊肿内切开引流术(附3例报告)%Pure transurethral natural orifice transluminal endoscopic surgery for fenestration and drainage treatment of renal cyst: report of three cases

    张国玺; 徐辉; 邹晓峰; 袁源湖; 肖日海; 杨军; 刘敏; 伍耿青; 王晓宁


    Objective:To describe the initial clinical experience of pure Transurethral NOTES for fenestration and drainage treatment of renal cyst, and evaluate its feasibility and safety. Method: From May to August 2012, two female patients and a male patient with renal cyst underwent pure Transurethral NOTES for fenestration and drainage treatment. The median age was 28. 6 (range 22 to 40) years. In this group, one renal cyst was on the right side and two on the left. All cases were confirmed by B ultrasound, CT scan and IVU. The median diameter of renal cyst was 6. 2(range 5. 2 to 7. 1)cm. After induction of general anesthesia, flexible ureter scope was tran-surethrally introduced into renal collect system. Renal cyst was found by B ultrasound guide when necessary. A crisscross incision was cut by Holmium laser to 1. 5-2. 0 cm, and a F7 double J stent was positioned with the proximal end coiled in the cyst cavity, which was removed after 4 weeks. Result: All procedures were successfully completed. One cyst was found by flexible ureter scope and the others were found by B ultrasound guide. The median operation time was 60 (range 30 to 125) min. There was no intraoperative or postoperative complication. The diameter of cyst decreased at least 1/2 during follow-up (3 to 6 months). Conclusion: Pure Transurethral NOTES for fenestration and drainage treatment of renal cyst is safe, feasible, minimal invasive and cosmetic. It is worth selecting the method to treat peripheral renal cyst.%目的:报告经尿道NOTES输尿管软镜下肾囊肿内切开引流术的初步经验,并评价其安全性和可行性.方法:对3例经B超、CT和IVU检查确诊的肾囊肿患者行经尿道NOTES肾囊肿内切开引流术治疗.左侧2例,右侧1例.术中经尿道置入输尿管软镜至收集系统,寻找囊肿;无法寻及者,辅助以B超定位.予钬激光于囊肿壁最薄处作“十”字切开,扩大切口至1.5~2.0 cm.留置F7输尿管双J管,将其近端留置于囊肿内.结果:3例手术均顺利.1例进镜至肾盂后寻及囊肿,2例在超声引导下定位.中位手术时间45(30~125)min,无大出血、周围脏器损伤、感染性休克等并发症发生.术后复查B超或CT示肾囊肿直径均缩小1/2以上.结论:经尿道NOTES输尿管软镜下肾囊肿内切开引流术具有安全、微创、简便可行、并发症少、恢复快、近期疗效确切、美容效果极佳等优点,适合内生性肾囊肿的治疗.

  2. 引发电控模块短路之PCB孔口发黑原因研究%Reason research on PCB orifice blackening phenomenon which caused electronic control module short-circuit



    PCB在使用过程中在经常会出现短路故障,对相关故障电子模块进行分析时发现模块PCB较多孔口存在发黑物质,严重者出现黑色物质连孔,通过测试确认黑色物质具有导电功能。本文通过理论分析及模拟实验论证,确认了黑色物质是引发电子模块故障的根源,同时明确了其产生机理,并提出了针对性的预防措施。%PCB short-circuit fault often occurred during use. It was found there was black substance around many holes of PCB when we analyzed the fault module. In some severe cases, connected holes occurred. The module ran normally again by removing the black substance. The black substance with conductivity was confirmed by test. In the paper, we confirmed that the black substance was the root cause of the electronic module failures through theoretical analysis and simulation experiments demonstrated. The generation mechanism was clarified and targeted preventive measures were proposed also.




    一台可工作在双向进气模式和小孔模式下的单级脉管制冷机,当双向进气方式采用并联双阀双向进气时,最低制冷温度为19.3 K,50 K以下的制冷量变化约为2 W/K;当双向进气阀门关闭时,制冷机就工作在小孔模式下,最近的研究工作发现,当制冷机工作在小孔模式下时出现了一个新的现象-脉管冷端温度存在温度回路,该特点与脉管冷端的热负荷及小孔开度的调节方法有关,该现象的发现对于理解双向进气模式下温度不稳定问题提供了一个新的思路.

  4. Design and Implementation of Orifice Trough Liquid Distributor Based on Visual Basic%基于Visual Basic的窄槽式液体分布器设计与实现

    高晓新; 刘栋梁; 郭新连


    引用Visual Basic中的ActiveX技术,将Visual Basic的可视化设计与Excel强大的数据表结合,建立窄槽式液体分布器的计算与数据报表,所建立的程序运行可靠,操作方便,数据结果便于设计人员设计.克服了传统的窄槽式液体分布器计算工作量大,耗时费力,效率低的缺点.

  5. Novel Totally Laparoscopic Endolumenal Rectal Resection With Transanal Natural Orifice Specimen Extraction (NOSE) Without Rectal Stump Opening: A Modification of Our Recently Published Clean Surgical Technique in a Porcine Model.

    Kvasha, Anton; Hadary, Amram; Biswas, Seema; Szvalb, Sergio; Willenz, Udi; Waksman, Igor


    Our group has recently described a novel technique for clean endolumenal bowel resection, in which abdominal and transanal approaches were used. In the current study, 2 modifications of this procedure were tested for feasibility in a porcine model. A laparoscopic approach to the peritoneal cavity was employed in rectal mobilization; this was followed by a transanal rectorectal intussusception and pull-through (IPT). IPT was established in a stepwise fashion. First, the proximal margin of resection was attached to the shaft of the anvil of an end-to-end circular stapler with a ligature around the rectum. Second, this complex was pulled transanally to produce IPT. Once IPT was established, a second ligature was placed around the rectum approximating the proximal and distal resection margins. This was followed by a purse string suture through 2 bowel walls, encircling the shaft of the anvil just proximal to the ligatures. The specimen was resected and extracted by making a full-thickness incision through the 2 bowel walls distal to the previously placed purse string suture and ligatures. The anastomosis was achieved by applying the stapler. The technique was found to be feasible. Peritoneal samples, collected after transanal specimen extraction, did not demonstrate bacterial growth. Although, this is a novel and evolving procedure, its minimally invasive nature, as well as aseptic bowel manipulation during endolumenal rectal resection, has the potential to limit the complications associated with abdominal wall incision and surgical site infection.

  6. 自动喷水灭火系统减压孔板的简化计算和应用%The simplified calculation and application of pressure reducing orifice plate for automatic sprinkler system

    肖睿书; 闰利国; 赵永代



  7. Chemotherapy or radio-chemotherapy for advanced adenocarcinoma of the oesophagus and cardiac orifice; Adenocarcinomes du bas oesophage et du cardia: quelle chimiotherapie ou chimioradiotherapie dans le traitement des recidives et des metastases

    Seitz, J.F.; Duffaud, F.; Dahan, L.; Ries, P.; Ville, E.; Laugier, R. [Centre Hospitalier Universitaire de la Timone, 13 - Marseille (France)


    Adenocarcinomas of esophagus and cardia represent in France approximately 20 to 40% of the esophagus cancers. They have a high risk to develop lymph nodes metastases and liver metastases. Currently, only 50 to 70% of patients may benefit from surgical curative resection at diagnosis, but more than 50% of them will recur. The standard of treatment of these metastatic adenocarcinomas is chemotherapy. Three large randomized comparative studies, between chemotherapy and supportive care, showed that chemotherapy significantly extends the median of survival (from 3-4 months to 10-12 months) and improves the quality of life. Currently, the combination of epirubicin-cisplatin-continuous 5FU (ECF) is the most effective regimen but it is difficult to administer and tolerate because of the long continuous 5FU infusion. In France, the most commonly used combination regimen still associates 5FU and cisplatin. New drugs (such as docetaxel, CPT11, oxaliplatin) used alone or in combination, especially with 5U, are very promising. Radio-chemotherapy is the preferred treatment for locoregional recurrences, because it improves dysphagia and enables to obtain complete tumor responses. Current results from concomitant radio-chemotherapy studies for esophagus cancer, based on 5FU alone, 5FU-cisplatin or 5FU-mitomycin, given as preoperative treatment or as exclusive treatment, support to use radio-chemotherapy for the treatment of loco-regional recurrences after surgical resection. Nevertheless, the optimal radio-chemotherapy schedule still remain to be defined (dose, duration, splitting of radiotherapy, choice of anticancer drugs). (authors)

  8. 鲁泊数和孔径比对直流互击式喷注器性能的影响%Effects of Rupe number and ratio of injection orifice diameter on unlike Impinging injector performance

    刘晓伟; 胡伟; 曹晶; 夏开红; 常小庆



  9. Numerical Simulation Research of V-shaped Orifice Regulating Ball Valve Based on CFD%基于CFD的V型孔板调节球阀数值模拟研究

    彭龑; 宗亮宇; 李淇阳



  10. To be a competent spokesperson of the Haihe River Basin, better governance of pollution discharge orifices%当好海河代言人管好入河排污口

    熊洋; 张增阁



  11. Extrusion process of corn stalk powder in single orifice die processing based on discrete element method%玉米秸秆粉料单模孔致密成型过程离散元模拟

    李永奎; 孙月铢; 白雪卫


    Mechanical behavior in the densification of biomass material is closely related to pellet quality. In order to explore the forming mechanism of typical biomass material from loose state to consolidation, the discrete element method (DEM) was introduced to investigate the movement and interaction of the milled corn stalk particles in the compacting process, and the verification experiments were carried out to test the effectiveness of the DEM simulation in this study. Firstly, the three-dimensional (3D) particle contact model of corn stalk powder based on the soft-sphere model of DEM was established, and the constraining walls in DEM model were completely consistent with the compressing cavity boundary conditions in geometric shape and dimension of experimental tests conducted in December, 2014; the loading speed in simulation was also set as the same value as the DEM model. Secondly, the diameter range of simulated particles was configured to 0.4-1.0 mm in accordance to the particle size distribution acquired through the screening experiment and calculation, and the generated particles were fully filled into the whole cavity at the original state before the compressing force was loaded. The mechanical parameters of the particles, such as normal stiffness, shear stiffness and friction coefficient between the 2 contact particles, were set to the values generated at random in specific range which was determined according to compacting experimental data. Thirdly, the comparison of compression stress relaxation data between tests and simulation was carried out and the validity of the simulation was verified by the hypothesis test. It was found that the force data with time from the hypothesis tests and DEM simulation followed the similar tendency, and the absolute error was not higher than 100 N in both initial loading stage and 20 seconds after stress relaxation. In the first 20 seconds of stress relaxation course, the values of absolute error were obviously higher than other time quantum. The consistency of the experimental and simulated data was fairly good on the whole, because there was little statistical significance between 2 group of data at 5% level in the significant difference analysis. The optimal numerical ranges of the mechanical parameters of the simulated particles in DEM model were also obtained. Namely, the normal stiffness was 1.2×104-1.8×104N/m, the shear stiffness was 0.8×104-1.3×104N/m and the friction coefficient was 0.10-0.12. Then, the compressive force was analyzed in DEM model at different compressive displacements, diameters and cone angles using the optimal mechanical parameters of particles. The result showed that the residual forces in stress relaxation were about 600 and 1 300 N respectively when the compressive displacements were set to 26 and 50 mm, which indicated that the compressive displacement had a great influence on pellet morphological stability while other parameters kept constant. When the diameter of single-hole die varied from 8 to 12 mm in DEM model, all the compression forces peaked near 1 100 N as compressing time went on, but the residual stress with 8 mm diameter was much higher than that with 12 mm, and in consideration of the consolidation degree, the recommended diameter was 8 mm compared with the mechanical behaviors of the diameter of 10 and 12 mm. The cone angle had a remarkable effect on the compression force, and the cone angle of 45° was suggested to get a reasonable balance between compression force and pellet density. The study indicates that the discrete element method provides an efficient and effective tool to address some engineering problems in biomass densification, and the soft-sphere model is appropriate to describe the mechanical behavior in the compression process of corn stalk powder.%为模拟粉碎后的玉米秸秆在单向受压状态下的力学行为,参照实际单模孔致密成型实验,建立了基于软球模型的秸秆粉料颗粒体系三维离散元模型,其约束边界条件与成型实验几何边界形态及尺寸一致.进行模拟分析时,颗粒接触模型的力学特性参数,如颗粒间法向刚度系数kn,切向刚度系数ks及摩擦系数μ,利用离散元模拟程序调试得出参数取值范围.将模拟得到的结果与实验测试数据进行比对与假设检验验证,结果显示数据一致性较好.得出离散元模拟时颗粒间力学特性参数最佳取值范围,分别为法向刚度系数(1.2~1.8)×104 N/m,切向刚度系数(0.8~1.3)×104N/m,摩擦系数 0.10~0.12.通过分析不同压缩位移、不同孔径以及不同锥角下的压缩与应力松弛曲线,建议成型模具孔径Φd=8 mm,锥角θ=45°,且应尽量增大压缩位移以防止秸秆成型块发生松散.离散单元法为研究玉米秸秆粉料致密过程力学行为提供了一种有效的分析手段.

  12. 梅花形孔板支撑换热器壳程流场的数值分析%Numerical Analysis of Flow Field in Shell Side of Cinquefoil Orifice-Baffle Support Type Heat Exchanger

    戴玉龙; 李志安; 王翠华; 陈玉博



  13. 改良尿道口旁阴茎包皮瓣尿道成形术的护理配合%Nursing coordination for patients undergoing improved urethral orifice side prepuce of penis skin flap urethroplasty



    @@ 尿道下裂是一种常见的男性泌尿生殖系统的先天性畸形,严重影响患儿正常发育,手术是唯一的治疗手段.近端型尿道下裂一期修复一直是泌尿外科难题之一[1].2002年起我院采用改良尿道口旁阴茎包皮瓣尿道成形术(改良Koyanagi术)治疗近端型尿道下裂病人43例,效果满意.现将手术配合总结如下.

  14. 船闸闸墙长廊道侧支孔水力特性%Hydraulic characteristics of long culvert with side branch orifices in wall of lock chamber

    黎贤访; 李云; 邓润兴



  15. 孔板支撑换热器壳程流场的数值预测%Numerical Prediction of Flow Field in Shell Side of the Orifice-Baffle Support Type Heat Exchanger

    董其伍; 吴金星; 刘敏珊; 魏新利



  16. Experimental on multiple bubble motion in a wedged orifice flow meter%楔形孔板流量计内多气泡的运动行为

    张一夫; 李维仲


      针对楔形孔板流量计多个气泡的运动,建立了对孔板流量计内气液两相流动的数学模型。采用贴体坐标系下同位网格的SIMPLE 算法解决速度与压力的耦合问题。利用贴体坐标下Level Set方法追踪两相界面的运动。通过模拟结果中节流截面含气律变化的分析,得出混相密度变化才是影响楔形孔板流量计测量精度的主要因素。因此,校正多相流的混相密度值是提高孔板流量计的测量精度,减小测量误差的最佳方法。

  17. 醒神开窍针刺法治疗难治性癫痫临床研究%Clinical Study of Mind-improving and Orifice-opening Acupuncture Treatment for Refractory Epilepsy

    罗卫平; 何宇峰; 王丽菊


    目的 观察醒神开窍针刺法治疗难治性癫痫对患者脑电图癫痫样波和背景活动的影响.方法 对60例难治性癫痫患者进行醒神开窍针刺法添加治疗,并进行常规脑电图检查.结果 加用醒神开窍针刺法治疗后,19%患者发作停止,总有效率达65%;48%患者出现轻、中度副反应.在治疗有效的患者(发作减少≥50%)发作间期癫痫样放电显著减少或消失,但有9.3%患者癫痫样放电反而增多;醒神开窍针刺法所致EEG背景活动异常(38.9%)表现为θ活动和δ活动增多,α活动减少.结论 醒神开窍针刺法是难治性癫痫的有效辅助治疗方法,癫痫样脑电活动的减少平行于发作频率的减少.

  18. Electromagnet Response Time Tests on Primary CRDM of a Prototype Gen-IV SFR

    Lee, Jae-Han; Koo, Gyeong-Hoi [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)


    This paper identifies the electromagnetic response characteristics of the electromagnet of a primary control rod drive mechanism (CRDM) used for the reactor scram function. The test measures the electromagnet response time required to release an armature from a stator controlled by a loss of an electromagnetic force on an armature after shorting a power supply to an electromagnet coil. These tests are carried out while changing the electromagnet core material, an assist spring, and an armature holding current. The main factors influencing the test parameters on the response are found to be the armature holding current for holding the armature loads, and the material type of the electromagnet cores. The minimum response time is 0.13 seconds in the case of using SS410 material as an armature, while the S10C material as an armature has a response time of 0.21 seconds. Electromagnet response time characteristics from the test results will be evaluated by comparing the precise moving data of an electromagnet armature through the use of a high-speed camera and a potentiometer in the future.

  19. Jump Conditions for Maxwell Equations and Their Consequences


    critical issues in computational modeling of electromagnetic systems containing sliding contacts, such as railguns , is the relationship armature is propelled by electromagnetic force. Two stationary conductors (rails) are connected to a capacitor bank. An armature, typically a solid...experimental results. 15. SUBJECT TERMS Maxwell equation, computational electromagnetics , jump condition 16. SECURITY CLASSIFICATION OF: 17

  20. Research on Key Factors and Their Interaction Effects of Electromagnetic Force of High-Speed Solenoid Valve

    Fan, Liyun; Xu, De; Ma, Xiuzhen; Song, Enzhe


    Analysis consisting of numerical simulations along with lab experiments of interaction effects between key parameters on the electromagnetic force based on response surface methodology (RSM) has been also proposed to optimize the design of high-speed solenoid valve (HSV) and improve its performance. Numerical simulation model of HSV has been developed in Ansoft Maxwell environment and its accuracy has been validated through lab experiments. Effect of change of core structure, coil structure, armature structure, working air gap, and drive current on the electromagnetic force of HSV has been analyzed through simulation model and influence rules of various parameters on the electromagnetic force have been established. The response surface model of the electromagnetic force has been utilized to analyze the interaction effect between major parameters. It has been concluded that six interaction factors including working air gap with armature radius, drive current with armature thickness, coil turns with side pole radius, armature thickness with its radius, armature thickness with side pole radius, and armature radius with side pole radius have significant influence on the electromagnetic force. Optimal match values between coil turns and side pole radius; armature thickness and side pole radius; and armature radius and side pole radius have also been determined. PMID:25243217

  1. 75 FR 28506 - Airworthiness Directives; Hawker Beechcraft Corporation (Type Certificate No. A00010WI Previously...


    ... ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and 3... with deficient armature insulating materials may have been installed on certain airplanes. We are proposing this AD to detect and replace starter generators with defective armature insulating...

  2. 75 FR 52235 - Airworthiness Directives; Hawker Beechcraft Corporation (Type Certificate No. A00010WI Previously...


    ..., 2010 (FR 75 28506). The NPRM proposed to detect and replace starter generators with deficient armature... and Procedures (44 FR 11034, February 26, 1979); and 3. Will not have a significant economic impact... AD results from reports that starter generators with deficient armature insulating materials may...

  3. Characteristics and applications of automatic membrane control valves; Eigenschaften und Einsatzmoeglichkeiten automatischer Membranregelventile

    Turnsek, Kevin [Saint-Gobain PAM, Saarbruecken (Germany)


    As a consequence of increasing energy consumption in systems engineering and process engineering, energy-efficient armature have become more important than ever before. Energy efficiency means, on the one hand, that armatures should be flow-optimised and, on the other hand, their energy consumption should be low.

  4. Sculpting Ceramic Heads.

    Sapiro, Maurice


    Clay sculpture is difficult to produce because of the requirements of kiln firing. The problems can be overcome by modeling the original manikin head and making a plaster mold, pressing molding slabs of clay into the plaster mold to form the hollow clay armature, and sculpting on the armature. (IS)

  5. Carbon Fibre-reinforced Polymer Strengthening and monitoring of the Gröndals Bridge in Sweden

    Täljsten, Björn; Hejll, A.; James, G.


    to be strengthened. The strengthening methods used were CFRP plates at the serviceability limit state and prestressed dywidag stays at the ultimate limit state. The strengthening was carried out during 2002. At the same time monitoring of the bridge commenced, using LVDT crack gauges as well as optical fiber sensors....

  6. Experiments with a Differential Transformer

    Aguilar, Horacio Munguía


    An experiment with an electric transformer based on single coils shows how electromagnetic induction changes when the magnetic coupling between coils is adjusted. This transformer has two secondary outputs which are taken differentially. This is the basis for a widely used position transducer known as LVDT.

  7. Experiments with a Differential Transformer

    Aguilar, Horacio Munguía


    An experiment with an electric transformer based on single coils shows how electromagnetic induction changes when the magnetic coupling between coils is adjusted. This transformer has two secondary outputs which are taken differentially. This is the basis for a widely used position transducer known as LVDT.

  8. Performance of an induction coil gun

    Shokair, I.R.; Cowan, M.; Kaye, R.J.; Marder, B.M.


    Performance of an electromagnetic induction launcher is considered for three types of armatures. These are: Solid, 1-element wound and 16-element wound aluminum ar natures. The one element wound armature has uniform current density throughout. Because of the radial distribution of the current density, the wound armature can withstand field reversal (working against embedded flux in the armature) and still maintain low temperature. Slingshot simulations were performed, for several configurations. Best performance was obtained for a single element wound armature with two field reversals. For a 60 kg projectile, 10.5 cm coil inner radius and 5.5 cm coil build, the velocity after 50 meters of launcher length (670 stages) exceeded 3.5 km/sec with an overall efficiency of about 45%. For the same parameters the solid and 16-element wound armatures reach a velocity of about 3.3 km/sec after 800 stages (60 meters of launcher length) but without field reversal. A velocity of 3.5 km/sec is possible after 60 meters of launcher length with the 16-element wound armature with one field reversal, but the temperature is close to the melting temperature of aluminum. In all simulations with a solid armature, melting of some of the surface material occurs. However, it is shown that most of the melting occurs after contribution has been made to the forward going pressure, that is, melting does not affect the electrical performance of the launcher. The effect of coil firing tune jitter on launcher performance is also considered and is found to be very small for realistic perturbations. For {plus_minus}2 {mu}-secs random jitter, the reduction in the final velocity for a 60 meter launcher with a solid armature is less than 0.1% and the increase in temperature is only 2%. This result holds for all types of armatures.

  9. Design Study of Fully Superconducting Wind Turbine Generators

    Song, Xiaowei (Andy); Mijatovic, Nenad; Jensen, Bogi Bech


    In this paper, two fully superconducting generators employing MgB2 armature winding, with YBCO and MgB2 field winding respectively, are presented and analyzed. The ac loss in armature winding is estimated, and a simple comparative study is carried out. The results show that both electromagnetic...... designs for fully superconducting generators are promising with respect to the power density. However, the cost of removing ac loss in armature winding is as high as $900 000. It is also noted that with the current price of YBCO tape, the generator employing MgB 2 field winding would have lower cost....

  10. Modeling of feed water check valves using RELAP5; Modellierung von Speisewasserrueckschlagventilen in RELAP5

    Ben Said, Nader; Bregulla, Wolfgang; Kalk, Andreas [Westinghouse Electric Germany GmbH, Mannheim (Germany)


    Westinghouse Electric Germany GmbH has developed fluid dynamic models for medium-actuated armatures using the thermal hydraulic code RELAP5 in order to reach a more realistic description of the armature behavior including fluid-structure interactions in case of transient flow conditions in piping systems. The contribution is concerned with the modeling of damped check valves. The model allows the description of the behavior during opening and closure of a check armature. The calculated results show good agreement with the available measured data.

  11. On One-dimensional Sound Analysis of a Duct Network with Helmholtz Resonators

    寺尾, 道仁; Terao, Michihito; 関根, 秀久; Sekine, Hidehisa; 大川, 真平; Okawa, Shinpei; 林, 大志; Hayashi, Daiji


    The outer orifice correction for Helmholtz resonators attached to the sidewall ofcircular ducts was studied. For the outer orifice correction when the axis direction ofthe orifice coincides with that of the duct, .explicit expressions were given by Ingard and Rschevkin. But their application to duct sections with duct-sidewall resonators is beyond their premise. An explicit expression ofthe outer orifice correction for duct-sidewall resonators was derived by conducting three-dimensionalbounda...

  12. Development and Application of Energetic Actuators for Shear and Vortex Dominated Flow Control


    while the actuator operates in single shot and burst modes. Figure 2.4: Four orifice actuator; a) side -view, b) top-view. 2.2.1. Reduced Ambient...high temperature from the electrical discharge increases the pressure inside the cavity, and an orifice array located on the cavity allows the air...volume, energy deposition, number of orifices and orifice diameter, among others. Initial validation of actuator performance was experimentally carried

  13. Material transport method and apparatus

    Ramsey, J. Michael; Ramsey, Roswitha S.


    An electrospray apparatus uses a microchannel formed in a microchip. Fluid is pumped through the channel to an outlet orifice using either hydraulic or electrokinetic means. An electrospray is generated by establishing a sufficient potential difference between the fluid at the outlet orifice and a target electrode spaced from the outlet orifice. Electrokinetic pumping is also utilized to provide additional benefits to microchip devices.

  14. 40 CFR Appendix B to Part 50 - Reference Method for the Determination of Suspended Particulate Matter in the Atmosphere (High...


    .... † This sample air inlet should be approximately uniform on all sides of the sampler. † The area of the... the calibration procedure are (1) an electronic mass flowmeter and (2) an orifice or orifices located... pressure gauge. A pressure recorder may be used with an orifice to provide a continuous record of the...

  15. ARDEC (Armament Research, Development, and Engineering Center) electric gun in-house test program-fiscal year 1988. Annual report, October 1987-September 1988

    Dunham, C.; Coradeschi, T.; Chang, D.I.; Van Camp, K.; Colombo, G.


    This report summarizes the experimental testing conducted on three railguns. It discusses improvements to the 30-megajoule homopolar generator and 250-kilojoule capacitor bank as well as instrumentation techniques and analysis capabilities. It also describes the planned high energy lab. The 50-mm square bore railgun demonstrated dramatic improvements in barrel wear with solid armatures of proper design. Tests on the short prototype of the 20-mm round bore railgun indicated that the composite structure will withstand the forces involved in the upcoming 5 km/sec tests using plasma armatures. The 50-mm round bore railgun short prototype tests pointed out the difficulties of designing solid round bore armatures and the importance of matching barrel stiffness and armature compliance.

  16. Limitations and Constraints of Eddy-Current Loss Models for Interior Permanent-Magnet Motors with Fractional-Slot Concentrated Windings

    Hui Zhang; Oskar Wallmark


    This paper analyzes and compares models for predicting average magnet losses in interior permanent-magnet motors with fractional-slot concentrated windings due to harmonics in the armature reaction...

  17. Rotor position sensor switches currents in brushless dc motors


    Reluctance switch incorporated in an induction motor is used for sensing rotor position and switching armature circuits in a brushless dc motor. This device drives the solar array system of an unmanned space satellite.


    Prema Kannan; Senthil Kumar Natarajan; Subhransu Sekar Dash


    .... A fuzzy logic controller is designed to change the pulse width of switching signal applied to the converter and thereby the voltage fed to the armature of the separately excited DC motor to regulate the speed...

  19. Apparatus for and method of operating a cylindrical pulsed induction mass launcher

    Cowan, M. Jr.; Duggin, B.W.; Widner, M.M.


    An electromagnetic cylindrical projectile mass launcher and a method of operation is provided which includes a cylindrical projectile having a conducting armature, a cylindrical barrel in which the armature is received, a plurality of electromagnetic drive coil stages, a plurality of pulse energy sources, and a pulsed power arrangement for generating magnetic pulses forming a pulsed magnetic wave along the length of the launcher barrel. The pulsed magnetic wave provides a propelling force on the projectile along the drive coil. The pulsed magnetic wave of the drive coil stages is advanced along the armature faster than the projectile to thereby generate an induced current wave in the armature. The pulsed generation of the magnetic wave minimizes electromagnetic heating of the projectile and provides for smooth acceleration of the projectile through the barrel of the launcher. 2 figs.

  20. Apparatus for and method of operating a cylindrical pulsed induction mass launcher

    Cowan, M. Jr.; Duggin, B.W.; Widner, M.M.


    An electromagnetic cylindrical projectile mass launcher and a method of operation is provided which includes a cylindrical projectile having a conducting armature, a cylindrical barrel in which the armature is received, a plurality of electromagnetic drive coil stages, a plurality of pulse energy sources, and a pulsed power arrangement for generating magnetic pulses forming a pulsed magnetic wave along the length of the launcher barrel. The pulsed magnetic wave provides a propelling force on the projectile along the drive coil. The pulsed magnetic wave of the drive coil stages is advanced along the armature faster than the projectile to thereby generate an induced current wave in the armature. The pulsed generation of the magnetic wave minimizes electromagnetic heating of the projectile and provides for smooth acceleration of the projectile through the barrel of the launcher. 2 figs.