WorldWideScience

Sample records for centered circular tube

  1. Energy dissipation in circular tube

    OpenAIRE

    A.D. Girgidov

    2012-01-01

    Energy dissipation distribution along the circular tube radius is important in solving such problems as calculation of heat transfer by the air flow through building envelope; calculation of pressure loss in spiral flows; calculation of cyclones with axial and tangential supply of dust-containing gas.Two types of one-dimensional radially axisymmetric flows in circular tube were considered: axial flow and rotation about the axis (Rankine vortex). Relying on two- and four-layer description of a...

  2. Energy dissipation in circular tube

    Directory of Open Access Journals (Sweden)

    A.D. Girgidov

    2012-01-01

    Full Text Available Energy dissipation distribution along the circular tube radius is important in solving such problems as calculation of heat transfer by the air flow through building envelope; calculation of pressure loss in spiral flows; calculation of cyclones with axial and tangential supply of dust-containing gas.Two types of one-dimensional radially axisymmetric flows in circular tube were considered: axial flow and rotation about the axis (Rankine vortex. Relying on two- and four-layer description of axial turbulent flow energy dissipation was calculated in each layer.Similar calculation for Rankine vortex with viscous sublayer at the tube surface was provided. By employing the dissipation minimum principle the boundary radius between rigid rotation and free vortex is calculated. Approximation of the velocity distribution in Rankine vortex is proposed.

  3. Capillary Penetration into Inclined Circular Glass Tubes.

    Science.gov (United States)

    Trabi, Christophe L; Ouali, F Fouzia; McHale, Glen; Javed, Haadi; Morris, Robert H; Newton, Michael I

    2016-02-01

    The spontaneous penetration of a wetting liquid into a vertical tube against the force of gravity and the imbibition of the same liquid into a horizontal tube (or channel) are both driven by capillary forces and described by the same fundamental equations. However, there have been few experimental studies of the transition from one orientation to the other. We report systematic measurements of capillary penetration of polydimethylsiloxane oils of viscosities 9.6, 19.2, and 48.0 mPa·s into glass capillary tubes. We first report the effect of tube radii R between 140 and 675 μm on the dynamics of spontaneous imbibition. We show that the data can be fitted using the exact numerical solution to the governing equations and that these are similar to fits using the analytical viscogravitational approximation. However, larger diameter tubes show a rate of penetration slower than expected using an equilibrium contact angle and the known value of liquid viscosity. To account for the slowness, an increase in viscosity by a factor (η/ρ)scaling is needed. We show full agreement with theory requires the ratio R/κ(-1) ∼ 0.1 or less, where κ(-1) is the capillary length. In addition, we propose an experimental method that enables the determination of the dynamic contact angle during imbibition, which gives values that agree with the literature values. We then report measurements of dynamic penetration into the tubes of R = 190 and 650 μm for a range of inclination angles to the horizontal, φ, from 5 to 90°. We show that capillary penetration can still be fitted using the viscogravitational solution, rather than the Bosanquet solution which describes imbibition without gravity, even for inclination angles as low as 10°. Moreover, at these low angles, the effect of the tube radius is found to diminish and this appears to relate to an effective capillary length, κ(-1)(φ) = (γLV/ρg sin φ)(1/2). PMID:26738739

  4. Elasto-plastic finite element analysis of squaring circular tube

    Institute of Scientific and Technical Information of China (English)

    HUANG Yuung-ming

    2008-01-01

    The flow rule of Prandtl-Reuss was adopted and incremental elasto-plastic finite-element analysis formulation of Coulomb's friction law combining the finite deformation theory was established,and Lagrangian formulation for simulating the squaring process of circular tube was updated.Incremental Coulomb's friction law was used in the global stiffness matrix to solve the sliding-sticking state of friction at the boundary contact interface.During the squaring process,the linear factor γmin was adopted to solve the non-linear boundary problems of changing node contact and separation,elasto-plastic transient situation in an element and the non-linear constitutive behavior of material so as to make each reasonable increment of the punch meet the demand of calculation for linear increment.The squaring process of circular tube,load distribution and final shape of work piece after unloading were simulated by this mode and compared with research data.It is known that the circular tube with higller geometrical ratio (R/t) could be pressed into symmetric square tube without collapse.This result can provide reference for the analysis of this process and evaluation and improvement of product defects.

  5. Forced circular seam welding of tubes automated with orbital heads

    Energy Technology Data Exchange (ETDEWEB)

    Boullion, R.; Weskott, D.

    1984-06-01

    The MG process with pulse width modulated current and cold wire filler is suitable mainly for the production of high-quality welded joints. Three orbital welding heads adapted to requirements of the nuclear power station constructor have been designed for the mechanized forced circular seam welding of tubes. They differ in respect of their scope, in the structural height and in the number of the motor - controllable functions and the maximal values of the parameters defined by the functions.

  6. Forced circular seam welding of tubes automated with orbital heads

    International Nuclear Information System (INIS)

    The MG process with pulse width modulated current and cold wire filler is suitable mainly for the production of high-quality welded joints. Three orbital welding heads adapted to requirements of the nuclear power station constructor have been designed for the mechanized forced circular seam welding of tubes. They differ in respect of their scope, in the structural height and in the number of the motor - controllable functions and the maximal values of the parameters defined by the functions. (orig.)

  7. Thermohydraulics of Turbulent Flow Through Heat Exchanger Tubes Fitted with Circular-rings and Twisted Tapes

    Institute of Scientific and Technical Information of China (English)

    Smith Eiamsa-ard; Vichan Kongkaitpaiboon; Kwanchai Nanan

    2013-01-01

    The influences of circular-ring turbulators (CRT) and twisted tape (TT) swirl generators on the heat transfer enhancement,pressure drop and thermal performance factor characteristics in a round tube are reported.The circular-ring turbulators were individually employed and together with the twisted tape swirl generators in the heated section of the tube.Three different pitch ratios (l/D =1.0,1.5,and 2.0) of the CRT and three different twist ratios (y/W=3,4,and 5) of the TT were introduced.The experiments were conducted using air as the working fluid under a uniform wall heat flux condition,for the Reynolds number between 6000 and 20000.The experimental resuits reveal that the heat transfer rate,friction factor and thermal performance factor of the combined CRT and TT are considerably higher than those of CRT alone.For the range examined,the ìncreases of mean Nusselt number,friction factor and thermal performance,in the tube equipped with combined devices,respectively,are 25.8%,82.8% and 6.3% over those in the tube with the CRT alone.The highest thermal performance factor of 1.42 is found for the combined device consisting of the CRT with l/D =1.0 and TT with y/W=3.The correlations of the Nusselt number,friction factor and thermal performance factor of the tubes with combined devices are also developed in terms of Reynolds number,Prandtl number,twist ratio and pitch ratio.

  8. Detailed structure of spinning detonation in a circular tube

    Energy Technology Data Exchange (ETDEWEB)

    Tsuboi, N. [Space Transportation Engineering Department, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Yoshinodai 3-1-1, Sagamihara, Kanagawa 229-8510 (Japan); Eto, K.; Hayashi, A.K. [Department of Mechanical Engineering, Aoyama Gakuin University, Fuchinobe 5-10-1, Sagamihara, Kanagawa 229-8558 (Japan)

    2007-04-15

    A single spinning detonation wave propagating in a circular tube, discovered experimentally in 1926, is simulated three-dimensionally with a detailed chemical reaction mechanism. The detonation front obtained numerically rotates periodically with a Mach leg, whiskers, and a transverse detonation. A long pressure trail, which is distributed from the transverse detonation to downstream, was reproduced, clearly showing that the pressure trail also spins synchronously with the transverse detonation. The formation of an unburned gas pocket behind the detonation front was not observed in the present simulations because the rotating transverse detonation completely consumed the unburned gas. The calculated profiles of instantaneous OH mass fraction have a keystone shape behind the detonation front. The numerical results for pitch, track angle, Mach stem angle, and incident shock angle on the tube wall agree well with the experimental results. (author)

  9. Critical heat flux in circular tube geometries using Freon-12

    International Nuclear Information System (INIS)

    Experimental and analytical investigations on critical heat flux have been performed in circular tubes of different diameters ranging from 2 mm to 16 mm. More than 1500 data points have been obtained in a large range of parameters: pressure 1.0 MPa to 3.0 MPa, mass flux 1.0 Mg/m2s to 6.0 Mg/m2s and exit steam quality -0.75 to +0.60. The effect of different parameters on CHF have been discussed. The test data have been compared with different CHF prediction methods. A very good agreement between the test data in the 8 mm diameter tube and the CHF look-up table shows that the test results in Freon-12 can be well transferred to water conditions by using fluid-to-fluid scaling laws available. The experimental data reveal that the effect of the tube diameter on CHF is governed mainly by exit steam quality and tube diameter itself. None of the equations or models available in the literature can reproduce the measured diameter effect with sufficient accuracy. (author)

  10. Velocity Profiles between Two Baffles in a Horizontal Circular Tube

    Institute of Scientific and Technical Information of China (English)

    Tae-Hyun Chang; Hae-Soo Lee; Keon-Je Oh; Doeg Hee Doh; Chang-Hoan Lee

    2014-01-01

    The shell and tube heat exchanger is an essential part of a power plant for recovering heat transfer between the feed water of a boiler and the wasted heat.The baffles are also an important element inside the heat exchanger.Internal materials influence the flow pattern in the bed.The influence of baffles in the velocity profiles was observed using a three-dimensional particle image velocimetry around baffles in a horizontal circular tube.The velocity of the particles was measured before the baffle and between them in the test tube.Results show that the flows near the front baffle flow were parallel to the vertical wall,and then concentrate on the upper opening of the front baffle.The flows circulate in the front and rear baffles.These flow profiles are related to the Reynolds number (Re) or the flow intensity.The velocity profiles at lower Re number showed a complicated mixing,concentrating on the lower opening of the rear baffle as front wall.Swirling flow was employed in this study,which was produced using tangential velocities at the inlet.At the entrance of the front baffle,the velocity vector profiles with swirl were much different from that without swirl.However,velocities between two baffles are not much different from those without swirl.

  11. Velocity profiles between two baffles in a horizontal circular tube

    Science.gov (United States)

    Chang, Tae-Hyun; Lee, Hae-Soo; Oh, Keon-Je; Doh, Doeg Hee; Lee, Chang-Hoan

    2014-12-01

    The shell and tube heat exchanger is an essential part of a power plant for recovering heat transfer between the feed water of a boiler and the wasted heat. The baffles are also an important element inside the heat exchanger. Internal materials influence the flow pattern in the bed. The influence of baffles in the velocity profiles was observed using a three-dimensional particle image velocimetry around baffles in a horizontal circular tube. The velocity of the particles was measured before the baffle and between them in the test tube. Results show that the flows near the front baffle flow were parallel to the vertical wall, and then concentrate on the upper opening of the front baffle. The flows circulate in the front and rear baffles. These flow profiles are related to the Reynolds number (Re) or the flow intensity. The velocity profiles at lower Re number showed a complicated mixing, concentrating on the lower opening of the rear baffle as front wall. Swirling flow was employed in this study, which was produced using tangential velocities at the inlet. At the entrance of the front baffle, the velocity vector profiles with swirl were much different from that without swirl. However, velocities between two baffles are not much different from those without swirl.

  12. 78 FR 49255 - Certain Circular Welded Carbon Steel Pipes and Tubes From Taiwan: Partial Rescission of...

    Science.gov (United States)

    2013-08-13

    ... Request for Revocation in Part, 78 FR 38924 (June 28, 2013). On July 25, 2013, Petitioner withdrew its... International Trade Administration Certain Circular Welded Carbon Steel Pipes and Tubes From Taiwan: Partial... certain circular welded carbon steel pipes and tubes from Taiwan. The period of review (POR) is May...

  13. 75 FR 18788 - Circular Welded Carbon Steel Pipes and Tubes from Thailand: Preliminary Results and Rescission...

    Science.gov (United States)

    2010-04-13

    ...: Circular Welded Carbon Steel Pipes and Tubes from Thailand, 51 FR 8341 (March 11, 1986). On March 2, 2009... Shipper Review Final Results, 75 FR at 4529-4530 (January 28, 2010). Allied Tube responded to Pacific Pipe... Review, 73 FR 61019 (October 15, 2008) (2006-2007 AR Final Results); see Circular Welded Carbon...

  14. A Numerical Investigation of Peristaltic Waves in Circular Tubes

    Science.gov (United States)

    Xiao, Q.; Damodaran, M.

    Peristaltic pumping is a process of fluid transport arising from the progressive waves, which travel along the walls of a flexible channel. It is a primary physiological transport mechanism that is inherent in many tubular organs of the human body such as the ureter, the gastro-intestinal tract, the urethra, and so on. Many studies exist in literature with the aim of understanding the characteristics of peristaltic flow under the assumption of low Reynolds number and infinitely long wavelength in a two-dimensional channel. However, peristaltic pumping is also the mechanism used in other industrial applications such as the blood pump for which the Reynolds number has a moderately high value. As studies concerning moderate to high Reynolds number flow in the circular tube are rare in literature, in the present study, the peristaltic flow of an incompressible fluid is numerically simulated using the finite volume method for solving the incompressible Navier-Stokes equations in primitive variable formulation by means of an infinite train of sinusoidal waves traveling along the wall of an axi-symmetric tube. The computational model presented in this work covers a wider range of Reynolds number (0.01-100), wave amplitude (0-0.8), and wavelength (0.01-0.4) than the those attempted in previous studies reported in literature and some new results pertaining to the distribution of velocity, pressure, wall shear stress for different peristaltic flow conditions characterizing flow at moderately higher Reynolds number have been obtained. The effect of the wave amplitude, wavelength, and Reynolds number on the "flow trapping" mechanism induced by peristalsis has also been investigated here for higher ranges of values of the parameters characterizing peristalsis.

  15. 77 FR 20782 - Circular Welded Carbon Steel Pipes and Tubes From Thailand: Preliminary Results of Antidumping...

    Science.gov (United States)

    2012-04-06

    ... investigation. See Antidumping Duty Order: Circular Welded Carbon Steel Pipes and Tubes From Thailand, 51 FR... Pipes and Tubes from Thailand, 51 FR 8341 (March 11, 1986). On March 1, 2011, the Department published a... Duty Order, Finding, or Suspended Investigation; Opportunity to Request Administrative Review, 76...

  16. 78 FR 34335 - Certain Circular Welded Carbon Steel Pipes and Tubes From Taiwan: Preliminary Results of...

    Science.gov (United States)

    2013-06-07

    ... of Antidumping Duties, 68 FR 23954 (May 6, 2003). Cash Deposit Requirements The following cash... Steel Pipes and Tubes From Taiwan: Antidumping Duty Order, 49 FR 19369 (May 7, 1984). These cash deposit... International Trade Administration Certain Circular Welded Carbon Steel Pipes and Tubes From Taiwan:...

  17. 77 FR 39736 - Certain Circular Welded Pipe and Tube From Brazil, India, Korea, Mexico, Taiwan, Thailand, and...

    Science.gov (United States)

    2012-07-05

    ...)] Certain Circular Welded Pipe and Tube From Brazil, India, Korea, Mexico, Taiwan, Thailand, and Turkey... and tube from Turkey and the antidumping duty orders on certain circular welded pipe and tube from....2(f)). Background The Commission instituted these reviews on July 1, 2011 (76 FR 38691)...

  18. Low-Loss Hollow-Core Anti-Resonant Fibers With Semi-Circular Nested Tubes

    DEFF Research Database (Denmark)

    Habib, Selim; Bang, Ole; Bache, Morten

    2016-01-01

    if the antiresonant tubes have nested tubes inside them, and here we investigate the role of the shape and position of these nested elements. By allowing the circular nested elements to become semi-circular, we selectively change the position or curvature of the nested elements. We find that the loss...... performance is quite insensitive to the curvature of the nested element, while the distance from the core boundary to the outer perimeter of the nested element is much more critical. Interestingly, the additional freedom of the semicircular nested elements allows optimizing them for a better loss performance...

  19. Studi Eksperimen Analisa Performa Compact Heat Exchanger Circular Tubes Continuous Plate Fin Untuk Pemanfaatan Waste Energy

    OpenAIRE

    Rachmadi Gewa Saputra; Ary Bachtiar Khrisna Putra

    2014-01-01

    Harga minyak dunia cenderung mengalami peningkatan dalam beberapa tahun terakhir sehingga manusia berfikir untuk memanfaatkan setiap penggunaan minyak bumi. Dengan berkembangnya teknologi saat ini waste energy yang berupa gas hasil pembakaran pada engine dapat dimanfaatkan menjadi bentuk energi lain menggunakan heat recovery system. Pada tugas akhir ini dilakukan desain sebuah heat exchanger tipe circular tubes continuous plate fin dengan susunan tube aligned yang digunakan untuk menyerap was...

  20. 75 FR 36635 - Circular Welded Carbon Steel Pipes and Tubes From Thailand: Rescission of Antidumping Duty...

    Science.gov (United States)

    2010-06-28

    ... FR 9162 (March 1, 2010). On March 31, 2010, we received a timely request from Saha Thai Steel Pipe... Revocation in Part, 75 FR 22107 (April 27, 2010). Rescission of Antidumping Duty Administrative Review The... International Trade Administration Circular Welded Carbon Steel Pipes and Tubes From Thailand: Rescission...

  1. 78 FR 21105 - Circular Welded Carbon Steel Pipes and Tubes From Thailand: Preliminary Results of Antidumping...

    Science.gov (United States)

    2013-04-09

    ..., available in Antidumping Duty Order: Circular Welded Carbon Steel Pipes and Tubes from Thailand, 51 FR 8341... Duty Administrative Review, 75 FR 26922, 26923 (May 13, 2010), unchanged in Magnesium Metal From the Russian Federation: Final Results of Antidumping Duty Administrative Review, 75 FR 56989 (September...

  2. 76 FR 71938 - Circular Welded Carbon Steel Pipes and Tubes From Thailand: Extension of Time Limit for...

    Science.gov (United States)

    2011-11-21

    ... Administrative Reviews, 76 FR 23545, 23546 (April 27, 2011). This review covers two producers/exporters of the... International Trade Administration Circular Welded Carbon Steel Pipes and Tubes From Thailand: Extension of Time... the antidumping duty order on circular welded carbon steel pipes and tubes from Thailand for...

  3. 75 FR 2487 - Circular Welded Carbon Steel Pipes and Tubes from Thailand: Court Decision Not in Harmony with...

    Science.gov (United States)

    2010-01-15

    ... Steel Pipes and Tubes from Thailand: Final Results of Antidumping Duty Administrative Review, 73 FR... International Trade Administration Circular Welded Carbon Steel Pipes and Tubes from Thailand: Court Decision... results of the administrative review of the antidumping order on circular welded carbon steel pipes...

  4. THE COUPLING IMPEDANCE OF A TOROIDAL BEAM TUBE WITH CIRCULAR CROSS SECTION

    International Nuclear Information System (INIS)

    IN THIS PAPER, THE LONGITUDINAL COUPLING IMPEDANCE OF A TOROIDAL BEAM TUBE WITH CIRCULAR CROSS SECION IS DERIVED IN THE FREQUENCY DOMAIN USING THE TOROIDAL COORDINATE SYSTEM. EXACT, ALTHOUGH COUPLED, DIFFERENTIAL EQUATIONS FOR THE AZIMUTHAL FIELD COMPONENTS ARE OBTAINED. AN APPROXIAMTE SOLUTION, VALID IN THE LIMIT OF SMALL CURVATURE, IS THEN DERIVED. ASSUMING EXTREME RELATIVISTIC ENERGIES AND A BEAM TUBE WITH PERFECTLY CONDUCTING WALLS, ONE FINDS A CLOSED-FORM EXPRESSION FOR THE PURELY REACTIVE COUPLING IMPEDANCE WHICH AT LOW MODE NUMBERS IS DEPENDENT ON THE TUBE GEOMETRY BUT WHICH AT VERY LARGE MODE NUMBERS APPROACHES THE FREE SPACE IMPEDANCE

  5. Deformation of a Circular Elastic Tube between Two Parallel Bars: Quasi-Analytical Geometrical Ring Models

    Directory of Open Access Journals (Sweden)

    A. Van Hirtum

    2015-01-01

    Full Text Available Several engineering problems are confronted with elastic tubes. In the current work, homothetic quasi-analytical geometrical ring models, ellipse, stadium, and peanut, are formulated allowing a computationally low cost ring shape estimation as a function of a single parameter, that is, the pinching degree. The dynamics of main geometrical parameters due to the model choice is discussed. Next, the ring models are applied to each cross section of a circular elastic tube compressed between two parallel bars for pinching efforts between 40% and 95%. The characteristic error yields less than 4% of the tubes diameter when the stadium model was used.

  6. 76 FR 66893 - Certain Circular Welded Carbon Steel Pipes and Tubes From India, Thailand, and Turkey; Final...

    Science.gov (United States)

    2011-10-28

    ..., 75 FR 69626, 69627 (November 15, 2010). Thailand--Welded Carbon Steel Pipe and Tube (A-549-502) The.... See Scope Rulings, 58 FR 27542, (May 10, 1993). Turkey--Welded Carbon Steel Pipe and Tube (A-489-501... Tubes from India, 51 FR 17384 (May 12, 1986); Antidumping Duty Order; Circular Welded Carbon Steel...

  7. Experimental research on fire resistance of circular steel tube column filled with steel-reinforced high-strength concrete

    OpenAIRE

    ZHU Siyi; ZHU Meichun; ZHENG Lilan; Yang, Jinghua; WANG Lvyi

    2014-01-01

    Circular steel tube filled with steel-reinforced high-strength concrete is a new model of composite column design.The fire resistance of this composite column was investigated experimentally.One circular steel tube column filled with steel-reinforced high-strength concrete and one circular steel tube column filled with high- strength concrete were tested under axial load and fire.The test results show that the axial deformations of both kinds of the composite columns under the same load level...

  8. Free vibrations of finite circular cylindrical shells and tubes with and without a surrounding fluid

    International Nuclear Information System (INIS)

    Numerical models are evaluated for determining the natural frequencies of thin-walled closed circular cylindrical shells and straight tube bundles in a fluid or without a fluid. Experiments are described to check the reliability of the numerical models. Some of the models are applied for the vibration analysis of some parts of the sodium-steam heat exchangers of the SNR-300 reactor in Kalkar (West Germany). (Auth.)

  9. Numerical Study on Heat Transfer Deterioration of Supercritical n-Decane in Horizontal Circular Tubes

    OpenAIRE

    Yanhong Wang; Sufen Li; Ming Dong

    2014-01-01

    In order to obtain a deeper understanding of the regenerative cooling process of scramjet engines, in this paper, a numerical investigation on the supercritical convective heat transfer of n-decane in horizontal circular tubes was conducted, based on a complete set of conservation equations and the Renormalization group (RNG) k–ε turbulence model with enhanced wall treatment. The present study mainly focuses on the heat transfer deterioration (HTD) phenomenon, including the mechanism and c...

  10. Kennedy Space Center Fixation Tube (KFT)

    Science.gov (United States)

    Richards, Stephanie E.; Levine, Howard G.; Romero, Vergel

    2016-01-01

    Experiments performed on the International Space Station (ISS) frequently require the experimental organisms to be preserved until they can be returned to earth for analysis in the appropriate laboratory facility. The Kennedy Fixation Tube (KFT) was developed to allow astronauts to apply fixative, chemical compounds that are often toxic, to biological samples without the use of a glovebox while maintaining three levels of containment (Fig. 1). KFTs have been used over 200 times on-orbit with no leaks of chemical fixative. The KFT is composed of the following elements: a polycarbonate main tube where the fixative is loaded preflight, the sample tube where the plant or other biological specimens is placed during operations, the expansion plug, actuator, and base plug that provides fixative containment (Fig. 2). The main tube is pre-filled with 25 mL of fixative solution prior to flight. When actuated, the specimen contained within the sample tube is immersed with approximately 22 mL (+/- 2 mL) of the fixative solution. The KFT has been demonstrated to maintain its containment at ambient temperatures, 4degC refrigeration and -100 C freezing conditions.

  11. Transport and deposition of nanoparticles in bend tube with circular cross-section

    Institute of Scientific and Technical Information of China (English)

    Peifeng Lin; Jianzhong Lin

    2009-01-01

    Transport and deposition of nanoparticles in bend tube with circular cross-section were simulated numerically for different Reynolds numbers and Dean numbers.A finite-volume code and the SIMPLE scheme were used to solve the equations.The results show that the distribution of nanoparticle concentration is symmetrical with respect to the top and bottom sides of the tube.The diameter of the nanoparticles has a weak effect on the distribution of nanoparticle concentration.The maximum and minimum of the deposition enhancement factor occur near the outside and inside walls of the bend tube,respectively.The higher the Reynolds number is,the shorter is the time for nanoparticle deposition.The bend curvature radius has a slight effect on the deposition enhancement factor.

  12. Computational Investigation on Fully Developed Periodic Laminar Flow Structure in Baffled Circular Tube with Various BR

    Directory of Open Access Journals (Sweden)

    Withada Jedsadaratanachai

    2014-01-01

    Full Text Available This paper presents a 3D numerical analysis of fully developed periodic laminar flow in a circular tube fitted with 45° inclined baffles with inline arrangement. The computations are based on a finite volume method, and the SIMPLE algorithm has been implemented. The characteristics of fluid flow are presented for Reynolds number, Re = 100–1000, based on the hydraulic diameter (D of the tube. The angled baffles were repeatedly inserted at the middle of the test tube with inline arrangement to generate vortex flows over the tested tube. Effects of different Reynolds numbers and blockage ratios (b/D, BR with a single pitch ratio of 1 on flow structure in the tested tube were emphasized. The flows in baffled tube show periodic flow at x/D ≈ 2-3, and become a fully developed periodic flow profiles at x/D ≈ 6-7, depending on Re, BR and transverse plane positions. The computational results reveal that the higher of BR and closer position of turbulators, the faster of fully developed periodic flow profiles.

  13. 76 FR 57020 - Circular Welded Carbon Steel Pipes and Tubes From Taiwan: Notice of Partial Rescission of...

    Science.gov (United States)

    2011-09-15

    ... Antidumping and Countervailing Duty Administrative Reviews and Request for Revocation in Part, 76 FR 37781... International Trade Administration Circular Welded Carbon Steel Pipes and Tubes From Taiwan: Notice of Partial... welded carbon steel pipes and tubes from Taiwan. The review covers eight firms. Based on a withdrawal...

  14. 77 FR 41967 - Certain Circular Welded Carbon Steel Pipes and Tubes From India, Thailand, and Turkey; Certain...

    Science.gov (United States)

    2012-07-17

    ... Review, 75 FR 69626, 69627 (November 15, 2010). Thailand--Welded Carbon Steel Pipe and Tube (A-549-502... remand. See Scope Rulings, 58 FR 27542 (May 10, 1993). Turkey--Welded Carbon Steel Pipe and Tube (A-489... Initiation of Five-Year (``Sunset'') Review, 76 FR 38613 (July 1, 2011). \\2\\ See Certain Circular...

  15. 76 FR 63902 - Circular Welded Carbon Steel Pipes and Tubes From Taiwan: Final Results of Antidumping Duty...

    Science.gov (United States)

    2011-10-14

    ... Welded Carbon Steel Pipes and Tubes From Taiwan, 76 FR 33210 (June 8, 2011) (Preliminary Results). This... Circular Welded Carbon Steel Pipes and Tubes From Taiwan: Antidumping Duty Order, 49 FR 19369 (May 7, 1984... section 773(b) of the Tariff Act of 1930, as amended (the Act). See Preliminary Results, 76 FR at...

  16. 77 FR 55807 - Circular Welded Carbon Steel Pipes and Tubes From Taiwan: Notice of Partial Rescission of...

    Science.gov (United States)

    2012-09-11

    ... Reviews and Request for Revocation in Part, 77 FR 40565 (July 10, 2012). On August 15, 2012, the... International Trade Administration Circular Welded Carbon Steel Pipes and Tubes From Taiwan: Notice of Partial... welded carbon steel pipes and tubes from Taiwan. The review covers four respondents. Based on...

  17. 77 FR 2318 - Certain Circular Welded Pipe and Tube From Brazil, India, Korea, Mexico, Taiwan, Thailand, and...

    Science.gov (United States)

    2012-01-17

    ...)] Certain Circular Welded Pipe and Tube From Brazil, India, Korea, Mexico, Taiwan, Thailand, and Turkey... countervailing duty order on welded carbon steel pipe and tube from Turkey, the antidumping duty orders on welded... proceed (76 FR 65748, October 24, 2011). A record of the Commissioners' votes, the Commission's...

  18. Brunam: a development centered on the tube

    International Nuclear Information System (INIS)

    In more than 20 years, the Brunam company has become a leader in the domain of tube intervention operations of three different kinds: prevention and analysis, onload operations, exploitation materials. The 1996 overturn of the company has improved with respect to 1995 and reached 40 millions of French Francs. Today's activity of the company is devoted to natural gas industry (50%), to petroleum and petrochemistry industry (40%), and to nuclear industry (10%). This short paper describes the three aspects of the company intervention operations and the research and development services provided to Gaz de France (GdF) company for the renovation of the French natural gas network. (J.S.)

  19. Gas-liquid annular flow in vertical circular tubes with liquid penetrated in nucleus

    International Nuclear Information System (INIS)

    A semi-analytical model is proposed for fully developed upward gas-liquid annular flow inside vertical circular tubes, by utilizing wall-known turbulence algebraic models for single-phase flows, within both streams, combined with empirical correlations for the gas-liquid interface friction factor. Direct integration of the associated momentum equations provide the velocity distribution for each phase, as well as overall quantities of practical interest such as liquid film thickness and pressure gradient. The effects of liquid droplets entrainment in the gas is specialized empirical correlations. Extensive comparisons with experimental results are made in order to demonstrate the consistency of the proposed model. (author)

  20. Improvement of Prandtl mixing length theory and application in modeling of turbulent flow in circular tubes

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In order to correctly predict tube cross section time-smoothed velocity distribution,friction factor and mass transfer behavior,two models for turbulent flow in circular tubes based on classical Prandtl mixing length theory and a modified mixing length were established.The results show that the modified mixing length includes the introduction of a damping function for the viscous sublayer and the second-order derivative to approximate eddy velocity.The calculated dimensionless time-smoothed velocityfrom the model based on Prandtl mixing length is much better than the result from the concept of eddy viscosity.The calculated eddy viscosity from the model based on modified mixing length is much better than the result from the model based on the classical Prandtl mixing length theory.And the friction factor calculated from the model based on the modified mixing length agrees well with the reported empirical relationships.

  1. Experimental research on mechanical properties of prestressed truss concrete composite beam encased with circular steel tube

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bo-yi; ZHENG Wen-zhong

    2009-01-01

    Tests of 4 simply supported unbonded prestressed truss concrete composite beams encased with circu-lar steel tube were carried out.It is found that the ratio of the stress increment of the unbonded tendon to that of the tensile steel tube is 0.252 during the using stage,and the average crack space of beams depends on the rati-o of the sum of the bottom chord steel tube's outside diameter and the secondary bottom chord steel tube's sec-area to the effective tensile concrete area.The coefficient of uneven crack distribution is 1.68 and the for-mula for the calculation of crack width is established.Test results indicate that the ultimate stress increment of unbonded tendon in the beams decreases in linearity with the increase of the composite reinforcement index βo.The pure bending region of beams accords with the plane section assumption from loading to failure.The calcu-lation formula of ultimate stress increment of the unbonded tendon and the method to caleulate the bearing ca-pacity ot normal section of beams have been presented.Besides,the method to calculate the stiffness of this sort of beams is brought forward as well.

  2. Shear strength and structural behaviours of HPRWO with web openings with circular steel tubes

    Science.gov (United States)

    Lee, S. J.; Park, J. M.

    2015-12-01

    The purpose of this study was to evaluate the shear strength and structural behavior of reinforced-concrete beams with web openings (hereinafter, “HPRWO”), where the web openings are reinforced with circular steel tubes. The experiments were conducted under the monotonic loading condition. Based on the structural experiments involving HPRWO, ultimate load ratio (d0,d0/h, etc.), ductility, load-deflection curve, and failure mode comparisons were made for evaluation purposes. This study utilized the design formula for predicting the shear strength proposed by the previous studies and formulas to determine the appropriate shear strength for HPRWO. The results of the experiments confirmed that the rigidity, ductility, and other properties of the HPRWO specimens reinforced with circular steel tubes, fiber, and admixtures were superior to those of the unreinforced HPRWOs. With Mansur's formula, a noticeable tendency for the increase in d0 and the sectional area of the web openings to lead to the overestimation of Vu/Vu,cal was found. The Vu/Vu,cal value was found to be more in line with the experiment results based on the AIJ formula compared with the results obtained using other formulas

  3. Local heat transfer downstream of an asymmetric abrupt expansion and cavity in a circular tube

    International Nuclear Information System (INIS)

    This study is concerned with measuring local heat transfer downstream of an asymmetric abrupt expansion and an asymmetric abrupt expansion followed by an asymmetric abrupt contraction (called 'asymmetric cavity') in a circular tube at a uniform wall temperature. The effects of geometry and three- dimensionality of the flow caused by asymmetric expansion on heat transfer characteristics are also examined. The flow just upstream of the expansion is unheated and fully developed at the entrance to the heated asymmetric abrupt expansion region. Local heat transfer coefficients are measured using a specially designed isothermal heat flux sensor. Measurements for the asymmetric abrupt expansion are made at a small to large diameter ratio of d/D = 0.4 and 0.533 for Reynolds numbers of ReD = 17,300 and 21,900, respectively. The eccentricities of the tube axis (e/D) are 0.25 and 0.17 for d/D = 0.4, and 0.195 and 0.065 for d/D = 0.533. For the asymmetric cavity, all tests are made at d/D = 0.4 and ReD = 17,300 with various cavity lengths for e/D = 0 and 0.25, respectively. For both cases, the variations of local Nusselt number are observed along the wall of downstream circular tube at several angular positions around the tube circumference. In general, the local Nusselt numbers downstream of an asymmetric abrupt expansion are substantially higher than the fully developed values for the range of Reynolds numbers, diameter ratios and eccentricities investigated, due to high turbulence and mixing action in the recirculation region. And the maximum Nusselt numbers occur between 10 and 15 step heights from the expansion step. The Nusselt number distributions for the asymmetric cavity show a dramatic increase to the maximum values as the downstream region of the cavity is approached. This behavior is attributed to a periodic vortex shedding, subsequent impingement on the downstream corner region of the cavity and three-dimensionality effects which cause an increase in turbulence

  4. AN EFFICIENT MOVING MESH METHOD FOR A MODEL OF TURBULENT FLOW IN CIRCULAR TUBES

    Institute of Scientific and Technical Information of China (English)

    Yin Yang; Yanping Chen; Yunqing Huang

    2009-01-01

    This paper presents an efficient moving mesh method to solve a nonlinear singular problem with an optimal control constrained condition. The physical problem is governed by a new model of turbulent flow in circular tubes proposed by Luo et al. using Prandtl's mixing-length theory. Our algorithm is formed by an outer iterative algorithm for handling the optimal control condition and an inner adaptive mesh redistribution algorithm for solving the singular governing equations. We discretize the nonlinear problem by using a upwinding approach, and the resulting nonlinear equations are solved by using the Newton-Raphson method. The mesh is generated and the grid points are moved by using the arc-length equidistribution principle. The numerical results demonstrate that proposed algorithm is effective in capturing the boundary layers associated with the turbulent model.

  5. Effect of superficial velocity on vaporization pressure drop with propane in horizontal circular tube

    Science.gov (United States)

    Novianto, S.; Pamitran, A. S.; Nasruddin, Alhamid, M. I.

    2016-06-01

    Due to its friendly effect on the environment, natural refrigerants could be the best alternative refrigerant to replace conventional refrigerants. The present study was devoted to the effect of superficial velocity on vaporization pressure drop with propane in a horizontal circular tube with an inner diameter of 7.6 mm. The experiments were conditioned with 4 to 10 °C for saturation temperature, 9 to 20 kW/m2 for heat flux, and 250 to 380 kg/m2s for mass flux. It is shown here that increased heat flux may result in increasing vapor superficial velocity, and then increasing pressure drop. The present experimental results were evaluated with some existing correlations of pressure drop. The best prediction was evaluated by Lockhart-Martinelli (1949) with MARD 25.7%. In order to observe the experimental flow pattern, the present results were also mapped on the Wang flow pattern map.

  6. Extension, inflation and torsion of a residually stressed circular cylindrical tube

    Science.gov (United States)

    Merodio, José; Ogden, Ray W.

    2016-03-01

    In this paper, we provide a new example of the solution of a finite deformation boundary-value problem for a residually stressed elastic body. Specifically, we analyse the problem of the combined extension, inflation and torsion of a circular cylindrical tube subject to radial and circumferential residual stresses and governed by a residual-stress dependent nonlinear elastic constitutive law. The problem is first of all formulated for a general elastic strain-energy function, and compact expressions in the form of integrals are obtained for the pressure, axial load and torsional moment required to maintain the given deformation. For two specific simple prototype strain-energy functions that include residual stress, the integrals are evaluated to give explicit closed-form expressions for the pressure, axial load and torsional moment. The dependence of these quantities on a measure of the radial strain is illustrated graphically for different values of the parameters (in dimensionless form) involved, in particular the tube thickness, the amount of torsion and the strength of the residual stress. The results for the two strain-energy functions are compared and also compared with results when there is no residual stress.

  7. Prediction of forced gas flows in circular tubes at high heat fluxes accompanied by laminarization

    International Nuclear Information System (INIS)

    The application of high heat fluxes to turbulent gas flows causes significant variation of the gas properties due to the large temperature increase, invalidating the use of design relations such as the popular Dittus-Boelter correlation and of conventional turbulence models. To develop turbulence models for such flows, the predictive capabilities of a Reynolds stress equation model (RSM) with turbulence heat flux equations and of a k-kL-(u'v')-bar model were examined. We have employed the turbulence stress-thermal energy gradient production, in the pressure-temperature fluctuation gradient correlation, for the turbulence heat flux equations, in order to improve the accuracy of predictions for heat transfer accompanied by laminarization. The k-kL-(u'v')-bar model has already been validated for gas flows in annular tubes; in this study its applicability to a circular tube was examined. Validations were performed by comparison of predictions with constant fluid properties at fully-established conditions and to experimental measurements extending to laminarization conditions. The turbulence models both predict laminar and turbulent results and the approximate transition Reynolds number for the fully-established flow at low heat fluxes. The results predicted with both models also agreed well with data on laminarizing flows. Thus, the models presented here are capable of predicting the flow reasonably from low to high heat fluxes. (author)

  8. 75 FR 28557 - Circular Welded Carbon Steel Pipes and Tubes From Thailand: Extension of Time Limit for Final...

    Science.gov (United States)

    2010-05-21

    ... Duty Administrative Review, 75 FR 18788 (April 13, 2010) (Preliminary Results). This administrative... Determination Deadlines Pursuant to the Tariff Act of 1930, As Amended, 70 FR 24533 (May 10, 2005). Accordingly... International Trade Administration Circular Welded Carbon Steel Pipes and Tubes From Thailand: Extension of...

  9. 77 FR 61738 - Circular Welded Carbon Steel Pipes and Tubes From Thailand: Final Results of Antidumping Duty...

    Science.gov (United States)

    2012-10-11

    ... Antidumping Duty Order: Circular Welded Carbon Steel Pipes and Tubes From Thailand, 51 FR 8341 (January 27... FR 20782 (April 6, 2012). DATES: Effective Date: October 11, 2012. FOR FURTHER INFORMATION CONTACT... Proceedings: Assessment of Antidumping Duties, 68 FR 23954 (May 6, 2003). Cash Deposit Requirements...

  10. 75 FR 1335 - Circular Welded Carbon Steel Pipes and Tubes from Taiwan; Extension of Time Limit for Preliminary...

    Science.gov (United States)

    2010-01-11

    ... Administrative Reviews and Requests for Revocation in Part, 74 FR 30052 (June 24, 2009). The current deadline for... Deadlines Pursuant to the Tariff Act of 1930, As Amended, 70 FR 24533 (May 10, 2005). We intend to issue the... International Trade Administration Circular Welded Carbon Steel Pipes and Tubes from Taiwan; Extension of...

  11. 76 FR 3612 - Circular Welded Carbon Steel Pipes and Tubes From Taiwan; Extension of Time Limit for Preliminary...

    Science.gov (United States)

    2011-01-20

    ... Antidumping and Countervailing Duty Administrative Reviews and Requests for Revocation in Part, 75 FR 37759... Taiwan: Notice of Partial Rescission of Antidumping Duty Administrative Review, 75 FR 70723 (November 18... International Trade Administration Circular Welded Carbon Steel Pipes and Tubes From Taiwan; Extension of...

  12. Potential flow around a row of spheres in a circular tube

    Energy Technology Data Exchange (ETDEWEB)

    Cai, X.; Wallis, G.B. (Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755-8000 (United States))

    1992-05-01

    The streamfunction for the flow of an ideal fluid through a tube containing an infinite row of equidistant stationary spheres has been obtained by extending the works of Smythe (Phys. Fluids {bold 4}, 756 (1961)) and Michael (Phys. Fluids {bold 8}, 1263 (1965)). Spheres whose separation of centers {ital L} varies from one diameter to infinity are considered, while the ratio of the tube and sphere radii {ital R} varies from one to infinity. With a relation developed by Wallis (Multiphase Sci. Technol. {bold 5}, 239 (1989)), the added (or virtual or apparent) mass coefficient per sphere has been found as a function of {ital R} and {ital L}. Direct numerical solutions of the problem using finite-element methods are in excellent agreement with the analytical results.

  13. ENERGY PERFORMANCE IMPROVEMENT, FLOW BEHAVIOR AND HEAT TRANSFER INVESTIGATION IN A CIRCULAR TUBE WITH V-DOWNSTREAM DISCRETE BAFFLES

    Directory of Open Access Journals (Sweden)

    Withada Jedsadaratanachai

    2013-01-01

    Full Text Available A mathematical study has been carried out to examine periodic laminar flow and heat transfer characteristics in a three-dimensional isothermal wall circular tube with 45° in-line V-discrete baffles. The computations are based on the Finite Volume Method (FVM and the SIMPLE algorithm has been implemented. The fluid flow and heat transfer characteristics are presented for Reynolds numbers based on the diameter of the circular tube ranging from 100 to 1200. To generate main streamwise vortex flows through the tested section, V-discrete baffles with an attack angle of 45° are mounted in tandem with in-line arrangement and pointing downstream (V-Downstream inserted in the middle of the tested tube. Effects of different Blockage Ratio (b/D, BR and Pitch Ratio (P/D, PR on heat transfer and pressure drop in the tube are studied. It is apparent that the main vortex flows can induce impinging flows on a wall of the interbaffle cavity leading to extreme increases in heat transfer rate over the circular tube. In addition, the rise in the BR and reduce of PR results in the increase in the Nusselt number and friction factor values. The computational results show that the optimum thermal enhancement factor is around 2.5 at BR = 0.15, PR = 1 and Re = 1200.

  14. Acoustic centering of a baffled piston in the circular harmonics domain.

    Science.gov (United States)

    Shabtai, Noam R; Vorländer, Michael

    2016-03-01

    The acoustic center of radiating sources is relevant to the modeling of radiation patterns and to their effective implementation in acoustical applications and computer models. However, the acoustic center of the sources may not be unique and therefore should be defined. Previously studied source centering algorithms used analytic methods for specific acoustic models, or applied post processing methods on a recorded sound from an acoustic source that was surrounded by a spherical microphone array. This work performs an acoustic centering of a radiating circular baffled piston that is formed by an open termination of a circular pipe. A signal processing based acoustic centering algorithm is redefined for this case and is shown to be correlated with the effective length of the pipe. PMID:27036274

  15. Pressure-driven flow past spheres moving in a circular tube

    Science.gov (United States)

    Sheard, G. J.; Ryan, K.

    A computational investigation, supported by a theoretical analysis, is performed to investigate a pressure-driven flow around a line of equispaced spheres moving at a prescribed velocity along the axis of a circular tube. This fundamental study underpins a range of applications including physiological circulation research. A spectral-element formulation in cylindrical coordinates is employed to solve for the incompressible fluid flow past the spheres, and the flows are computed in the reference frame of the translating spheres.Both the volume flow rate relative to the spheres and the forces acting on each sphere are computed for specific sphere-to-tube diameter ratios and sphere spacing ratios. Conditions at which zero axial force on the spheres are identified, and a region of unsteady flow is detected at higher Reynolds numbers (based on tube diameter and sphere velocity). A regular perturbation analysis and the reciprocal theorem are employed to predict flow rate and drag coefficient trends at low Reynolds numbers. Importantly, the zero drag condition is well-described by theory, and states that at this condition, the sphere velocity is proportional to the applied pressure gradient. This result was verified for a range of spacing and diameter ratios. Theoretical approximations agree with computational results for Reynolds numbers up to O(100).The geometry dependence of the zero axial force condition is examined, and for a particular choice of the applied dimensionless pressure gradient, it is found that this condition occurs at increasing Reynolds numbers with increasing diameter ratio, and decreasing Reynolds number with increasing sphere spacing.Three-dimensional simulations and predictions of a Floquet linear stability analysis independently elucidate the bifurcation scenario with increasing Reynolds number for a specific diameter ratio and sphere spacing. The steady axisymmetric flow first experiences a small region of time-dependent non

  16. Analytical Study of A Two-Phase Model For Steady Flow of Blood in A Circular Tube

    Directory of Open Access Journals (Sweden)

    S.R. Verma and Anuj Srivastava

    2014-12-01

    Full Text Available The present paper deals with a mathematical model of blood flow through narrow circular tube. The model consists of a core region of suspension of all the erythrocytes assumed to be a power law fluid and a peripheral cell-depleted layer of plasma as a Newtonian fluid. The system of differential equations has been solved analytically. The expressions for velocity profile, Bluntness parameter, flow rate, the ratio of core hematocrit to discharge hematocrit (Hc/HD, apparent viscosity (µapp, and the ratio of tube hematocrit to discharge hematocrit (HT/HD and shear stress at the wall have obtained. Some of them have been discussed through graphs.

  17. Heat Transfer Coefficient during Evaporation of R-1234yf, R-134a, and R-22 in Horizontal Circular Small Tubes

    OpenAIRE

    Kwang-Il Choi; Nguyen-Ba Chien; Jong-Taek Oh

    2013-01-01

    Experimental data of heat transfer coefficient during evaporation of R-1234yf, R-134a, and R-22 in horizontal circular small tubes are compared. The local heat transfer coefficient is obtained for heat fluxes ranging from 10 to 35 kW m−2, mass fluxes ranging from 100 to 650 kg m−2 s−1, saturation temperatures of 5, 10, and 15°C, and quality up to 1.0. The test sections are made of stainless steel tubes with inner diameters of 1.5 and 3.0 mm, the lengths of 1000 and 2000. Effects of heat flux,...

  18. Circular magnetic dichroism of the Fa center adsorption in KCl doped with Li and Na

    International Nuclear Information System (INIS)

    The spin-orbit structure of FA in KCl:Li and KCl:Na have been studied by means of the magnetic circular dichroism. Due to their C4V, symmetry the FA centers have two different spin-orbit parameters, Δ* and Δ*, which only in the KCl:Li case follow the relation: Δ* F A centers have been determined using the method of moment

  19. Numerical Investigation of Air-Side Heat Transfer and Pressure Drop in Circular Finned-Tube Heat Exchangers

    OpenAIRE

    Mon, Mi Sandar

    2009-01-01

    A three-dimensional numerical study is performed to investigate the heat transfer and pressure drop performance on the air-side of circular finned tube bundles in cross flow. New heat transfer and pressure drop correlations for the air-cooled heat exchangers have been developed with the Reynolds number ranging from 5000 to 70000. The heat transfer and pressure drop results agree well with several existing experimental correlations. In addition, the influence of the geometric parameters on the...

  20. Dynamical Centers and Non-Circular Motions in THINGS Galaxies: Implications for Dark Matter Halos

    CERN Document Server

    Trachternach, C; Walter, F; Brinks, E; Kennicutt, R C

    2008-01-01

    We present harmonic decompositions of the velocity fields of 19 galaxies from THINGS (The \\HI Nearby Galaxy Survey) which quantify the magnitude of the non-circular motions in these galaxies and yield observational estimates of the elongations of the dark matter halo potentials. Additionally, we present accurate dynamical center positions for these galaxies. We show that the positions of the kinematic and photometric centers of the large majority of the galaxies in our sample are in good agreement. The median absolute amplitude of the non-circular motions, averaged over our sample, is $6.7 \\kms$, with $\\sim 90$ percent of the galaxies having median non-circular motions of less than $\\sim 9\\kms$. As a fraction of the total rotation velocity this translates into 4.5 percent on average. The mean elongation of the gravitational potential, after a statistical correction for an unknown viewing angle, is $0.017\\pm 0.020$, i.e., consistent with a round potential. Our derived non-circular motions and elongations are s...

  1. Effect of adhesive on the strengthening of aluminum foam-filled circular tubes

    OpenAIRE

    Toksoy, Ahmet Kaan; Tanoğlu, Metin; Güden, Mustafa; Hall, Ian W.

    2004-01-01

    Studies of the crushing behavior of closed-cell, aluminum foam-filled aluminum and steel tubes have shown an interaction effect between tubewall and foam filler [1, 2, 3]. The crushing loads of foam-filled tubes are, therefore, found to be higher than the sum of the crushing loads of foam (alone) and tube (alone) mainly due to this effect. Santosa et al. [1], based on FEM results, proposed the following equation for the average crushing load of foam-filled square tubes of length b,

  2. Flow and Displacement of Non-Newtonian Fluid(Power-Law Model) by Surface Tension and Gravity Force in Inclined Circular Tube

    International Nuclear Information System (INIS)

    This paper presents the theoretical analysis of a flow driven by surface tension and gravity in an inclined circular tube. A governing equation is developed for describing the displacement of a non-Newtonian fluid(Power-law model) that continuously flows into a circular tube owing to surface tension, which represents a second-order, nonlinear, non-homogeneous, and ordinary differential form. It was found that quantitatively, the theoretical predictions of the governing equation were in excellent agreement with the solutions of the equation for horizontal tubes and the past experimental data. In addition, the predictions compared very well with the results of the force balance equation for steady

  3. Effects of entrance configuration on pressure loss and heat transfer of transitional gas flow in a circular tube

    International Nuclear Information System (INIS)

    Pressure loss and heat transfer of a transitional gas flow are affected significantly by the entrance configuration. The friction factor and the heat transfer coefficient were measured using a circular tube with four different kinds of entrance configurations. The Reynolds number at the transition from laminar to intermittent flow was varied from about 1,940 to 9,120. The intermittency factor was measured for heated and unheated flows ; and the relation between the intermittency and the friction factor or heat transfer coefficient was examined. Several existing correlations were tested and found to correlate with the experimental results fairly well. (author)

  4. EFFECTS OF VISCOUS DISSIPATION ON THERMALLY DEVELOPING FORCED CONVECTION IN A POROUS SATURATED CIRCULAR TUBE WITH AN ISOFLUX WALL

    Institute of Scientific and Technical Information of China (English)

    Kamel Hooman; Alireza Pourshaghaghy; Arash Ejlali

    2006-01-01

    The viscous dissipation effect on forced convection in a porous saturated circular tube with an isoflux wall is investigated on the basis of the Brinkman flow model.For the thermally developing region, a numerical study is reported while a perturbation analysis is presented to find expressions for the temperature profile and the Nusselt number for the fully developed region. The fully developed Nusselt number found by numerical solution for the developing region is compared with that of asymptotic analysis and a good degree of agreement is observed.

  5. Heat transfer augmentation in a circular tube with winglet vortex generators☆

    Institute of Scientific and Technical Information of China (English)

    Suriya Chokphoemphun; Monsak Pimsarn; Chinaruk Thianpong; Pongjet Promvonge

    2015-01-01

    The article presents the influence of winglet vortex generators (WVGs) placed in the core flow area on ther-mal performance enhancement of a tube heat exchanger. The experiment was carried out in a uniform wall heat-fluxed tube by varying turbulent alrflow for Reynolds number ranging from 5300 to 24000. In the pres-ent work, the WVGs with an attack angle of 30° were inserted into the test tube at four different winglet pitch ratios (RP=P/D) and three winglet-width or blockage ratios (RB=e/D). The experimental results at various RP and RB values were evaluated and compared with those for smooth tube and tubes with twist-ed tape or wire coil. The measurement reveals that the WVGs enhance considerably the heat transfer and friction loss above the plaln tube, wire coil and twisted tape. The Nusselt number and friction factor increase with the increment of RB and Re but with the decreasing RP. The average Nusselt numbers for the WVGs with various RB are in the range of 2.03–2.34 times above the plaln tube. The thermal performance for the WVGs is found to be much higher than that for the wire coil and twisted tape and is in a range of 1.35–1.59. Also, a numerical investigation is conducted to study the flow structure and heat transfer enhancement mecha-nisms in the winglet-inserted tube.

  6. Visualization of two-phase gas-liquid flow regimes in horizontal and slightly-inclined circular tubes

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Livia Alves [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Nuclear Engineering Institute (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)], E-mail: livia@lasme.coppe.ufrj.br; Cunha Filho, Jurandyr; Su, Jian [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), RJ (Brazil). Nuclear Engineering Program], Emails: cunhafilho@lasme.coppe.ufrj.br, sujian@lasme.coppe.ufrj.br; Faccini, Jose Luiz Horacio [Nuclear Engineering Institute (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)], E-mail: faccini@ien.gov.br

    2010-07-01

    In this paper a flow visualization study was performed for two-phase gas-liquid flow in horizontal and slightly inclined tubes. The test section consists of a 2.54 cm inner diameter stainless steel circular tube, followed by a transparent acrylic tube with the same inner diameter. The working fluids were air and water, with liquid superficial velocities ranging from 0:11 to 3:28 m/s and gas superficial velocities ranging from 0:27 to 5:48 m/s. Flow visualization was executed for upward flow at 5 deg and 10 deg and downward flow at 2:5 deg, 5 deg and 10 deg, as well as for horizontal flow. The visualization technique consists of a high-speed digital camera that records images at rates of 125 and 250 frames per second of a concurrent air-water mixture through a transparent part of the tube. From the obtained images, the flow regimes were identified (except for annular flow), observing the effect of inclination angles on flow regime transition boundaries. Finally, the experimental results were compared with empirical and theoretical flow pattern maps available in literature. (author)

  7. 78 FR 21107 - Circular Welded Carbon Steel Pipes and Tubes from Turkey: Preliminary Results of Countervailing...

    Science.gov (United States)

    2013-04-09

    ... Steel Pipes and Tubes from Turkey (Preliminary Decision Memorandum) from Edward C. Yang, Senior Director... 5084: Allocation of Free Land and Purchase of Land for less than Adequate Remuneration (LTAR) F....

  8. Deforming mechanism of non-mandrel drawing process of circular aluminium tube by simulation

    Institute of Scientific and Technical Information of China (English)

    QUAN Guo-zheng; ZHOU Jie; WANG Meng-han; QUAN Guo-hui; TONG Ying

    2006-01-01

    The aluminium tubes with high strength and smooth outer-surface can be produced by non-mandrel drawing process. It is an effective method to study forming mechanism of drawing process by simulation, based on which the relevant dies with reasonable dimensions can be designed to ensure tube precision. The dynamic model and elasto-plastic finite element model of the forming process were established based on FEM software Deform-3D, then the simulation was performed. The expressions about drawing load were deduced, and the influence of friction coefficient on drawing load was computed by the expressions and software respectively. Based on simulation results the deformation mechanism of drawing process without plug was expounded. According to flowing speed vector graph the law of material flowing was summarized, by which the deformation regions were partitioned.Furthermore, some potential problems of drawing process such as diameter shrinking, thickness varying were forecast and analyzed quantificationally.

  9. An open-styled dielectric-lined azimuthally periodic circular waveguide for a millimeter wave traveling-wave tube

    Institute of Scientific and Technical Information of China (English)

    Liu Yang; Wei Yan-Yu; Xu Jin; Yin Hai-Rong; Yue Ling-Na; Gong Yu-Bin; Wang Wen-Xiang

    2012-01-01

    An open-styled dielectric-lined azimuthally periodic circular waveguide (ODLAP-CW) for a millimeter-wave traveling-wave tube (TWT) is proposed,which is a modified form of a dielectric-lined azimuthally periodic circular waveguide (DLAP-CW).The slow-wave characteristics of the open-styled DLAP-CW are studied by using the spatial harmonics method,which includes normalized phase velocity and interaction impedance.The complicated dispersion equations are numerically solved with MATLAB and the results are in good agreement with the simulation results obtained from HFSS.The influence of structural parameters on the RF properties is investigated based on our theory.The numerical results show that the optimal thickness of the metal rod can increase the interaction impedance,with the dielectric constant held fixed.Finally,the slow-wave characteristics and transmission properties of an open-styled structure are compared with those of the DLAP-CW.The results validate that the mode competition is eliminated in the improved structure with only a slight influence on the dispersion characteristics,which may significantly improve the stability of an open-styled DLAP-CW-based TWT,and the interaction efficiency is also improved.

  10. CFD analysis of heat transfer and friction factor charaterstics in a circular tube fitted with horizontal baffles twisted tape inserts

    Science.gov (United States)

    Salman, Sami D.; Kadhum, Abdul Amir H.; Takriff, Mohd S.; Bakar Mohamad, Abu

    2013-12-01

    Swirl/vortex flow generator is an important form of passive augmentation techniques. Twisted-tape is one of the most important members of this form which is used extensively in different type heat exchangers. This paper reports the effect of twisted tape inserts on heat transfer and friction factor characteristics in circular tube under constant heat flux and laminar flow conditions using CFD simulation. Plain twisted tape inserts with twist ratios (y = 2.93, 3.91) and baffled twisted tape inserts with twist ratio (y = 2.93) have been used for the simulation using Fluent version 6.3.26. The results obtained by simulation matched with the literature correlations for plain tube with the discrepancy of less than ± 8% for Nusselt number and ± 6.25% for friction factor. The results have also revealed that the heat transfer in term of the Nusselt number enhanced with increases of Reynolds number, decreases of twist ratio and baffle insert. Among the various twist ratios, the twisted tape with twist ratio of y=2.93 and baffle is offered a maximum heat transfer enhancement.

  11. CFD analysis of heat transfer and friction factor charaterstics in a circular tube fitted with horizontal baffles twisted tape inserts

    International Nuclear Information System (INIS)

    Swirl/vortex flow generator is an important form of passive augmentation techniques. Twisted-tape is one of the most important members of this form which is used extensively in different type heat exchangers. This paper reports the effect of twisted tape inserts on heat transfer and friction factor characteristics in circular tube under constant heat flux and laminar flow conditions using CFD simulation. Plain twisted tape inserts with twist ratios (y = 2.93, 3.91) and baffled twisted tape inserts with twist ratio (y = 2.93) have been used for the simulation using Fluent version 6.3.26. The results obtained by simulation matched with the literature correlations for plain tube with the discrepancy of less than ± 8% for Nusselt number and ± 6.25% for friction factor. The results have also revealed that the heat transfer in term of the Nusselt number enhanced with increases of Reynolds number, decreases of twist ratio and baffle insert. Among the various twist ratios, the twisted tape with twist ratio of y=2.93 and baffle is offered a maximum heat transfer enhancement

  12. Twisted-tape-induced swirl flow heat transfer and pressure drop in a short circular tube under velocities controlled

    International Nuclear Information System (INIS)

    The twisted-tape-induced swirl flow heat transfer due to exponentially increasing heat inputs with various exponential periods (Q=Q0exp(t/τ), τ=7, 14 and 23 s) and the twisted-tape-induced pressure drop were systematically measured with mass velocities, G, ranging from 4022 to 15140 kg/m2s by an experimental water loop flow. Measurements were made on a 6 mm inner diameter, a 59.2 mm effective length and a 0.4 mm thickness of Platinum circular test tube which was spot-welded two potential taps on the outer surface of a 69.6 mm heated length. The twisted tapes with twist ratios, y [=H/d=(pitch of 180deg rotation)/d], of 2.39, 3.39 and 4.45 were used in this work. The relation between the swirl velocity and the pump input frequency and that between the fanning friction factor and Reynolds number (Red=2.04x104 to 9.96x104) were clarified. The twisted-tape-induced swirl flow heat transfers with y=2.39, 3.39 and 4.45 were compared with the values calculated by our correlation of the turbulent heat transfer for the empty tube and other worker's one for the circular tube with the twisted-tape-insert. The influence of y and Reynolds numbers based on swirl velocity, Resw, on the twisted-tape-induced swirl flow heat transfer was investigated into details and the widely and precisely predictable correlation of the twisted-tape-induced swirl flow heat transfer was derived based on the experimental data. The correlation can describe for the twisted-tape-induced swirl flow heat transfer for the wide ranges of twist ratios (y=2.39 to 4.45), mass velocities (G=4022 to 15140 kg/m2s) and Reynolds numbers based on swirl velocity (Resw=2.88x104 to 1.22x105) within 0 to +30% difference. (author)

  13. Twisted-tape-induced swirl flow heat transfer and pressure drop in a short circular tube under velocities controlled

    International Nuclear Information System (INIS)

    The twisted-tape-induced swirl flow heat transfer due to exponentially increasing heat inputs with various exponential periods (Q = Q0 exp(t/τ), τ = 7, 14 and 23 s) and the twisted-tape-induced pressure drop were systematically measured with mass velocities, G, ranging from 4022 to 15,140 kg/m2 s by an experimental water loop flow. Measurements were made on a 59.2 mm effective length which was spot-welded two potential taps on the outer surface of a 6 mm inner diameter, a 69.6 mm heated length and a 0.4 mm thickness of platinum circular test tube. The twisted tapes with twist ratios, y [=H/d = (pitch of 180° rotation)/d], of 2.39, 3.39 and 4.45 were used in this work. The relation between the swirl velocity and the pump input frequency and that between the fanning friction factor and Reynolds number (Red = 2.04 × 104 to 9.96 × 104) were clarified. The twisted-tape-induced swirl flow heat transfers with y = 2.39, 3.39 and 4.45 were compared with the values calculated by our correlation of the turbulent heat transfer for the empty tube and other worker's one for the circular tube with the twisted-tape insert. The influence of y and Reynolds numbers based on swirl velocity, Resw, on the twisted-tape-induced swirl flow heat transfer was investigated into details and the widely and precisely predictable correlation of the twisted-tape-induced swirl flow heat transfer was derived based on the experimental data. The correlation can describe for the twisted-tape-induced swirl flow heat transfer for the wide ranges of twist ratios (y = 2.39–4.45), mass velocities (G = 4022–15140 kg/m2 s) and Reynolds numbers based on swirl velocity (Resw = 2.88 × 104 to 1.22 × 105) within −10 to +30% difference.

  14. Experimental investigation of enhanced heat transfer for fined circular tube heat exchanger with rectangular fins

    Institute of Scientific and Technical Information of China (English)

    LI Yong-xing; YANG Dong; CHEN Ting-kuan

    2006-01-01

    Presents a set of data for flow and heat transfer of finned-tube bundle under the condition of high air flow velocity. Air flow and heat transfer over a 4 ×4 ( columns × rows) finned-tube heat exchanger with rectangular fins was investigated experimentally in a wind tunnel with constant wall temperatures condition. The air flow velocity based on the minimum flow cross-section area over flow channel ranged from 13.8 to 50. 2 m/s,the heat transfer rate ranged from 21.8 to 47. 1 kW, and the air temperatures increase ranged from 10. 9 to 19. 8°C. The present results were compared with results calculated from correlations proposed by CSPE. For air flow velocity less than 25 m/s, these two results of heat transfer agreed well with each other, whereas for larger velocity, our test data disagreed with the CSPE correlations. For the friction factor, present data are much higher than the predicted results in the whole range. Finally, correlations for friction factors and heat transfer coefficients are proposed based on the experimental results.

  15. Combined gas radiation and laminar mixed convection in vertical circular tubes

    International Nuclear Information System (INIS)

    A numerical study of the interaction between thermal radiation and laminar mixed convection for ascending flows of emitting and absorbing gases in vertical tubes is presented. The radiative properties of the flowing gases, H2O, CO2 and H2O-CO2 mixtures are modeled by using the global absorption distribution function model. The temperature-dependent thermophysical properties are considered when solving the flow field and energy balance equations. Results are presented in terms of velocity and temperature fields, and of evolution of centerline velocity, friction factor and heat fluxes. The effects of radiation on the regime of reverse flow occurrence are also examined. It is shown that, for heated gases, radiation tends to reduce the velocity distortion effect of buoyancy. Radiative transfer delays then significantly the occurrence of reverse flow for heated gases while, for cooled gases, the flow regime is practically not affected

  16. A comparison of FBP and BPF reconstruction methods for circular X-ray tomography with off-center detector

    NARCIS (Netherlands)

    Schäfer, D.; Grass, M.; Van de Haar, P.

    2011-01-01

    Circular scanning with an off-center planar detector is an acquisi-tion scheme that allows to save detector area while keeping a largefield of view (FOV). Several filtered back-projection (FBP) algorithmshave been proposed earlier. The purpose of this work is to present twonewly developed back-

  17. Numerical prediction of local transitional features of turbulent forced gas flows in circular tubes with strong heating

    International Nuclear Information System (INIS)

    Previous numerical simulation for the laminarization due to heating of the turbulent flow in pipe were assessed by comparison with only macroscopic characteristics such as heat transfer coefficient and pressure drop, since no experimental data on the local distributions of the velocity and temperature in such flow situation was available. Recently, Shehata and McEligot reported the first measurements of local distributions of velocity and temperature for turbulent forced air flow in a vertical circular tube with strongly heating. They carried out the experiments in three situations from turbulent flow to laminarizing flow according to the heating rate. In the present study, we analyzed numerically the local transitional features of turbulent flow evolving laminarizing due to strong heating in their experiments by using the advanced low-Re two-equation turbulence model. As the result, we successfully predicted the local distributions of velocity and temperature as well as macroscopic characteristics in three turbulent flow conditions. By the present study, a numerical procedure has been established to predict the local characteristics such as velocity distribution of the turbulent flow with large thermal-property variation and laminarizing flow due to strong heating with enough accuracy. (author). 60 refs

  18. Characteristics of Spherical Shock Wave and Circular Pulse Jet Generated by Discharge of Propagating Shock Wave at Open End of Tube

    Institute of Scientific and Technical Information of China (English)

    Tsukasa Irie; Tsuyoshi Yasunobu; Hideo Kashimura; Toshiaki Setoguchi; Kazuyasu Matsuo

    2003-01-01

    When the shock wave propagating in the straight circular tube reaches at the open end, the impulsive wave is generated by the emission of a shock wave from an open end, and unsteady pulse jet is formed near the open end behind the impulsive wave under the specific condition. The pulse jet transits to spherical shock wave with the increase in the strength of shock wave. The strength is dependent on the Mach number of shock wave, which attenuates by propagation distance from the open end. In this study, the mechanism of generating the unsteady pulse jet, the characteristics of the pressure distribution in the flow field and the emission of shock wave from straight circular tube which has the infinite flange at open end are analyzed numerically by the TVD method. Strength of spherical shock wave, relation of shock wave Mach number, distance decay of spherical shock wave and directional characteristics are clarified.

  19. Numerical models to predict steady and unsteady thermal-hydraulic behaviour of supercritical water flow in circular tubes

    International Nuclear Information System (INIS)

    Highlights: • A CFD model and 1-D code THRUST are developed to simulate the supercritical water flows. • The supercritical flows with the normal heat transfer and deteriorated heat transfer are simulated. • The numerical results are compared with the experimental data and the errors are reported. • The transient simulations are also carried out using the CFD and THRUST. • The transient results obtained using the CFD and THRUST are compared under different conditions. - Abstract: The present paper is aimed at the development of numerical models to predict steady and unsteady thermal-hydraulic behaviour of supercritical water flow at various operating conditions. A simple one-dimensional numerical thermal-hydraulic model based on a finite-difference scheme has been developed. A detailed CFD analysis based on two turbulence models, Reynolds Stress Model and k–ω SST model, has also been presented in this paper. Seven experimental cases of steady state and vertically up flowing supercritical water in circular tubes operated at various working regimes, such as normal and deteriorated heat transfer regions, are used to validate the numerical models. Comparisons for steady state flow show good agreement between the numerical and experimental results for all normal heat transfer cases and most of the deteriorated heat transfer cases. Next, the numerical models are used for transient simulations. Three case studies are undertaken with a purpose to quantify the time dependent responses from both the 1-D model and CFD model. The comparisons carried out for both the normal and deteriorated heat transfer conditions show a good agreement between the two numerical models

  20. A robust Hough transform algorithm for determining the radiation centers of circular and rectangular fields with subpixel accuracy

    International Nuclear Information System (INIS)

    Uncertainty in localizing the radiation field center is among the major components that contribute to the overall positional error and thus must be minimized. In this study, we developed a Hough transform (HT)-based computer algorithm to localize the radiation center of a circular or rectangular field with subpixel accuracy. We found that the HT method detected the centers of the test circular fields with an absolute error of 0.037 ± 0.019 pixels. On a typical electronic portal imager with 0.5 mm image resolution, this mean detection error was translated to 0.02 mm, which was much finer than the image resolution. It is worth noting that the subpixel accuracy described here does not include experimental uncertainties such as linac mechanical instability or room laser inaccuracy. The HT method was more accurate and more robust to image noise and artifacts than the traditional center-of-mass method. Application of the HT method in Winston-Lutz tests was demonstrated to measure the ball-radiation center alignment with subpixel accuracy. Finally, the method was applied to quantitative evaluation of the radiation center wobble during collimator rotation.

  1. A robust Hough transform algorithm for determining the radiation centers of circular and rectangular fields with subpixel accuracy.

    Science.gov (United States)

    Du, Weiliang; Yang, James

    2009-02-01

    Uncertainty in localizing the radiation field center is among the major components that contribute to the overall positional error and thus must be minimized. In this study, we developed a Hough transform (HT)-based computer algorithm to localize the radiation center of a circular or rectangular field with subpixel accuracy. We found that the HT method detected the centers of the test circular fields with an absolute error of 0.037 +/- 0.019 pixels. On a typical electronic portal imager with 0.5 mm image resolution, this mean detection error was translated to 0.02 mm, which was much finer than the image resolution. It is worth noting that the subpixel accuracy described here does not include experimental uncertainties such as linac mechanical instability or room laser inaccuracy. The HT method was more accurate and more robust to image noise and artifacts than the traditional center-of-mass method. Application of the HT method in Winston-Lutz tests was demonstrated to measure the ball-radiation center alignment with subpixel accuracy. Finally, the method was applied to quantitative evaluation of the radiation center wobble during collimator rotation. PMID:19124954

  2. 77 FR 32508 - Circular Welded Carbon Steel Pipes and Tubes From Turkey: Notice of Preliminary Results of...

    Science.gov (United States)

    2012-06-01

    ... Order; Welded Carbon Steel Standard Pipe and Tube Products From Turkey, 51 FR 17784 (May 15, 1986..., 76 FR 33204, 33208 (June 8, 2011), unchanged in Certain Welded Carbon Steel Pipe and Tube From Turkey... Tube from Turkey; Notice of Preliminary Results of Antidumping Duty Administrative Review, 76 FR...

  3. Study of heat transfer in circular tubes with supercritical fluid by the STAR-CCM+ CFD code

    International Nuclear Information System (INIS)

    Supercritical Cooled-Water Reactor (SCWR) which is planned to be deployed by 2030 derives its concept from Light Water Reactors (Boiling Water Reactor (BWR), Pressurized Water Reactor (PWR) and Fossil Fired Coal Plant but with a simpler design. Due to the strong variations of density at supercritical pressure, the SCWR is likely to inherit some of the issues related to the LWR’s in terms of heat transfer (e.g. thermal crisis). This research was undertaken in order to better understand the phenomena of heat transfer as applied to SCWR and also to test the applicability of Reynolds-Average Navier-Stokes (STARCCM+ CFD code). Kim’s et al., (2005) data which employs supercritical CO2 as a simulant of water at 8 MPa was used to test the applicability. The computational simulation by STAR-CCM+ on the prediction of a 2-D axisymmetric heat transfer of carbon dioxide at supercritical pressure flowing upward through heated cross-section of a circular tube was performed with six (6) low-Reynolds number models; κ -epsilon AKN, EB, standard low- Re and V2F with two κ -ω turbulence models; SST and standard Wilcox with low y+ wall treatment. The results of heat fluxes of 20, 23, 30 and 40 kW/m2 and mass flux of 314 kg/m2s were compared to the experimental data of Kim et al, (2005). The Standard low Reynolds turbulence models were seen to have better capabilities to predict the heat transfer behaviour of supercritical CO2 as observed in the experiment. The κ -ω models did not perform favourably in the prediction of heat transfer deterioration. The V2F turbulence model performed better than the other models quantitatively when compared to the experimental data. The results of the simulation has been found to be able to reproduce the general features exhibited in the experimental data even though they over predicted the observed heat transfer deterioration both quantitatively and qualitatively. (author)

  4. Shock Tube and Ballistic Range Facilities at NASA Ames Research Center

    Science.gov (United States)

    Grinstead, Jay H.; Wilder, Michael C.; Reda, Daniel C.; Cornelison, Charles J.; Cruden, Brett A.; Bogdanoff, David W.

    2010-01-01

    The Electric Arc Shock Tube (EAST) facility and the Hypervelocity Free Flight Aerodynamic Facility (HFFAF) at NASA Ames Research Center are described. These facilities have been in operation since the 1960s and have supported many NASA missions and technology development initiatives. The facilities have world-unique capabilities that enable experimental studies of real-gas aerothermal, gas dynamic, and kinetic phenomena of atmospheric entry.

  5. Fuel assembly mechanical behavior with respect to center guide tube welding points

    International Nuclear Information System (INIS)

    A fuel assembly with modified welding procedure between the center guide tube and sleeves on grid structures is proposed in the work, and some mechanical behavior of the fuel assembly is presented. While all sleeves on grid assemblies are welded to center guide tube in the present design, the modified fuel assembly with reduced welding is proposed. To evaluate mechanical performance of the design, lateral bending deflection test and lateral vibration test were performed in a test facility. Applying a lateral static load at 6-th grid, the fuel assembly deflection at each grid was measured in the lateral static test. In the vibration test, displacement signal at every grid is measured while the fuel assembly is excited by a dynamic shaker at the 6-th grid. Processing the measured signals, modal properties such as natural frequency, damping, and mode shapes can be found based on frequency response functions. The test results, comparing to a previous design with all girds welding to the center guide tube, do not show any notable deviation in the structural behaviors

  6. 77 FR 46713 - Circular Welded Carbon Steel Pipes and Tubes From Turkey: Final Results of Countervailing Duty...

    Science.gov (United States)

    2012-08-06

    ... Steel Pipe and Tube Products From Turkey, 51 FR 7984 (March 7, 1986). \\5\\ See Preliminary Results, 77 FR... Results of Countervailing Duty Administrative Review, 77 FR 19623 (April 2, 2012) (Preliminary Results... Welded Carbon Steel Standard Pipe and Tube from Turkey: Notice of Rescission of Countervailing...

  7. Flow topology, heat transfer characteristic and thermal performance in a circular tube heat exchanger inserted with punched delta winglet vortex generators

    International Nuclear Information System (INIS)

    To improve the heat transfer rate and thermal performance, the punched delta winglet vortex generators, DWVGs, were inserted in the middle of the circular tube heat exchanger. The effects of the flow attack angles and the flow directions were investigated numerically for the Reynolds number Re = 100 – 2000. The finite volume method and the SIMPLE algorithm were used to study. The results are reported in terms of the flow structure, heat transfer behavior and thermal performance evaluation and also compared with the smooth tube with no vortex generators. As the numerical results, the use of the DWVGs in the tube can improve the heat transfer rate and thermal performance by creating the vortex flow through the tested section. The rise of the flow attack angle results in the increasing strength of the vortex flows. The flow attack angle of 25 .deg. performs the highest heat transfer rate and thermal performance, while the flow attack angle of 0 .deg. gives the reversed results. The computational results reveal that the optimum thermal enhancement factor is around 2.80 at Re = 2000, α = 25 .deg., with the winglet tip pointing downstream. The correlations on both the Nusselt number ratio and friction factor ratio for the DWVG in the tube heat exchanger are presented

  8. Digital tomosynthesis (DTS) with a Circular X-ray tube: Its image reconstruction based on total-variation minimization and the image characteristics

    Science.gov (United States)

    Park, Y. O.; Hong, D. K.; Cho, H. S.; Je, U. K.; Oh, J. E.; Lee, M. S.; Kim, H. J.; Lee, S. H.; Jang, W. S.; Cho, H. M.; Choi, S. I.; Koo, Y. S.

    2013-09-01

    In this paper, we introduce an effective imaging system for digital tomosynthesis (DTS) with a circular X-ray tube, the so-called circular-DTS (CDTS) system, and its image reconstruction algorithm based on the total-variation (TV) minimization method for low-dose, high-accuracy X-ray imaging. Here, the X-ray tube is equipped with a series of cathodes distributed around a rotating anode, and the detector remains stationary throughout the image acquisition. We considered a TV-based reconstruction algorithm that exploited the sparsity of the image with substantially high image accuracy. We implemented the algorithm for the CDTS geometry and successfully reconstructed images of high accuracy. The image characteristics were investigated quantitatively by using some figures of merit, including the universal-quality index (UQI) and the depth resolution. For selected tomographic angles of 20, 40, and 60°, the corresponding UQI values in the tomographic view were estimated to be about 0.94, 0.97, and 0.98, and the depth resolutions were about 4.6, 3.1, and 1.2 voxels in full width at half maximum (FWHM), respectively. We expect the proposed method to be applicable to developing a next-generation dental or breast X-ray imaging system.

  9. Two-center interference in molecular photoelectron energy spectra with intense attosecond circularly polarized XUV laser pulses

    Science.gov (United States)

    Yuan, Kai-Jun; Bian, Xue-Bin; Bandrauk, André D.

    2014-08-01

    We study two-center electron interference in molecular photoionization processes by intense attosecond circularly polarized extreme ultraviolet (XUV) laser pulses in both symmetric H2+ and nonsymmetric HHe2+ one-electron diatomic systems. Simulations from numerical solutions of time-dependent Schrödinger equations for the oriented symmetric molecular ion H2+ exhibit a signature of interference with double peaks (minima) in molecular attosecond photoelectron energy spectra (MAPES) at critical angles ϑc between the continuum electron momentum pe and the molecular internuclear R axis. The interference patterns are shown to be influenced by the molecular Coulomb potential, leading to a shift of the critical angle ϑc. Dependence of the two-center interference on the pulse ellipticity is also investigated. Furthermore, it is found that the interference phenomena are critically sensitive to the molecular orbital symmetry. For the nonsymmetric molecular ion HHe2+, such double peaks in MAPES also occur, thus suggesting a method for imaging orbitals in molecules by intense ultrashort circularly polarized XUV pulses on the attosecond time scale.

  10. INTEGRAL TRANSFORM SOLUTION FOR THE FORCED CONVECTION OF HERSCHEL-BULKLEY FLUIDS IN CIRCULAR TUBES AND PARALLEL-PLATES DUCTS

    Directory of Open Access Journals (Sweden)

    J. N. N. QUARESMA

    1998-03-01

    Full Text Available The thermal entry region in laminar forced convection of Herschel-Bulkley fluids is solved analytically through the integral transform technique, for both circular and parallel-plates ducts, which are maintained at a prescribed wall temperature or at a prescribed wall heat flux. The local Nusselt numbers are obtained with high accuracy in both developing and fully-developed thermal regions, and critical comparisons with previously reported numerical results are performed.

  11. 76 FR 27987 - Circular Welded Carbon Steel Pipes and Tubes From Thailand: Amended Final Results of Antidumping...

    Science.gov (United States)

    2011-05-13

    ... Review, 73 FR 61019 (October 15, 2008) (Final Results). FOR FURTHER INFORMATION CONTACT: Jacqueline... Not in Harmony with Final Results of Administrative Review, 75 FR 2487 (January 15, 2010). On February... Tubes From Thailand: Amended Final Results of Antidumping Duty Administrative Review, 75 FR...

  12. 78 FR 286 - Circular Welded Carbon Steel Pipes and Tubes From Turkey; Amended Final Results of Antidumping...

    Science.gov (United States)

    2013-01-03

    ... and Tube From Turkey: Notice of Final Results of Antidumping Duty Administrative Review, 76 FR 76939..., 77 FR 72818 (December 6, 2012) (Final Results). \\2\\ The Borusan Group includes the following entities...., Borusan Ithicat ve Dagitim A.S., and Tubeco Pipe and Steel Corporation. See Final Results, 77 FR at...

  13. 77 FR 72818 - Circular Welded Carbon Steel Pipes and Tubes From Turkey; Final Results of Antidumping Duty...

    Science.gov (United States)

    2012-12-06

    ... Standard Pipe and Tube Products From Turkey, 51 FR 17784, 17784 (May 15, 1986). Notification to Importers... Turkey: Notice of Preliminary Results of Antidumping Duty Administrative Review, 77 FR 32508 (June 1...\\ \\3\\ See id., 77 FR at 32510. \\4\\ See id., 77 FR at 32512. On October 23, 2012, the Department...

  14. 75 FR 73033 - Circular Welded Carbon Steel Pipes and Tubes from Thailand: Amended Final Results of Antidumping...

    Science.gov (United States)

    2010-11-29

    ... Thailand: Final Results of Antidumping Duty Administrative Review, 75 FR 64696 (October 20, 2010). The... clarification, see Antidumping and Countervailing Duty Proceedings: Assessment of Antidumping Duties, 68 FR... Carbon Steel Pipes and Tubes From Thailand: Final Determination of Sales at Less Than Fair Value, 51...

  15. 78 FR 64916 - Circular Welded Carbon Steel Pipes and Tubes From Turkey: Final Results of Countervailing Duty...

    Science.gov (United States)

    2013-10-30

    ... Review; Calendar Year 2011, 78 FR 21107 (April 9, 2013) (Preliminary Results). \\2\\ See Decision... parties. \\3\\ See Countervailing Duty Order: Certain Welded Carbon Steel Pipe and Tube Products From Turkey, 51 FR 7984 (March 7, 1986). \\4\\ See Preliminary Results. \\5\\ Petitioners in this review are...

  16. 75 FR 4529 - Circular Welded Carbon Steel Pipes and Tubes From Thailand: Final Results of Antidumping Duty New...

    Science.gov (United States)

    2010-01-28

    ... Steel Pipes and Tubes from Thailand: Preliminary Results of Antidumping Duty New Shipper Review, 74 FR... New Shipper Review, 74 FR 59961 (November 19, 2009). Scope of the Order The products covered by this... Less Than Fair Value, 51 FR 3384 (January 27, 1986). These cash deposit requirements shall remain...

  17. 75 FR 62366 - Circular Welded Carbon Steel Pipes and Tubes From Taiwan: Final Results of Antidumping Duty...

    Science.gov (United States)

    2010-10-08

    ... Welded Carbon Steel ] Pipes and Tubes From Taiwan, 75 FR 32911 (June 10, 2010) (Preliminary Results...) of the Act. See Preliminary Results, 75 FR at 32913. Those results apply to these final results... accordance with section 773(a)(4) of the Act. See Preliminary Results, 75 FR 32913. Analysis of...

  18. CFD simulation of the effect of particle size on the nanofluids convective heat transfer in the developed region in a circular tube.

    Science.gov (United States)

    Davarnejad, Reza; Barati, Sara; Kooshki, Maryam

    2013-12-01

    The CFD simulation of heat transfer characteristics of a nanofluid in a circular tube under constant heat flux was considered using Fluent software (version 6.3.26) in the laminar flow. Al2O3 nanoparticles in water with concentrations of 0.5%, 1.0%, 1.5%, 2% and 2.5% were used in this simulation. All of the thermo-physical properties of nanofluids were assumed to be temperature independent. Two particle sizes with average size of 20 and 50 nm were used in this research. It was concluded that heat transfer coefficient increased by increasing the Reynolds number and the concentration of nanoparticles. The maximum convective heat transfer coefficient was observed at the highest concentration of nano-particles in water (2.5%). Furthermore, the two nanofluids showed higher heat transfer than the base fluid (water) although the nanofluid with particles size of 20 nm had the highest heat transfer coefficient. PMID:23687629

  19. PENGARUH VARIASI DIAMETER TUBE PIPA EVAPORATOR DENGAN CIRCULAR FINS TERHADAP PRESSURE DROPS ALIRAN REFRIGERANT PADA SISTEM REFRIGERASI

    Directory of Open Access Journals (Sweden)

    Nanang Ruhyat

    2015-02-01

    Full Text Available Kebutuhan akan mesin pendingin udara di Indonesia sangat tinggi karena iklim tropis yang menyebabkan Indonesia memiliki dua musim, yaitu musin kemarau dan musin penghujan. Namun pada beberapa tahun ini, musim kemarau atau secara awam dikatakan musim panas, terasa lebih panjang dibanding musim hujan. Sistem refrigerasi dipilih untuk kebutuhan pendingin udara di Indonesia khususnya dan asia pada umumnya. Sistem refrigrasi terdiri dari evaporator, condenser, kompresser dan katup ekspansi. Efek pendinginan terjadi di evaporator, dimana cairan refrigerant berubah menjadi uap atau yang disebut dengan proses evaporasi. Pada penelitian ini, evaporator dirancang menggunakan beberapa diameter tube  pipa evaporator, yaitu :  0,005435 m, 0,007036 m, 0,008103 m,  0,008407 m, 0,009398 m, 0,010338 m, 0,011278 m, 0,00125 m, 0,012954 m dan 0,014224 m. Perancangan evaporator untuk biaya perancangan yang optimum dipilih pada rancangan dengan Din 0,009398 m dan Dout 0,0127 dengan panjang tube 5,08 m karena ukuran dan panjang tube yang tidak terlalu besar dan panjang.

  20. Performance analysis of turbulent convection heat transfer of Al2O3 water-nanofluid in circular tubes at constant wall temperature

    International Nuclear Information System (INIS)

    The present paper analyzes the turbulent convection of Al2O3-water nanofluid inside a circular section tube subjected to constant wall temperature. The analysis is developed numerically by using the mixture model, which has been proved to be a convenient method to simulate nanofluids behavior. The numerical model is successfully validated by means of analytical equations and experimental correlations. The study is focused on the analysis of the performance of Al2O3-water nanofluid within the considered device. Performance indicators based on the first and second law of thermodynamics are taken into account and analyzed. At the increase of nanofluid concentration, the Nusselt number increases, but entropy generation and pumping power also increase, therefore the penalties overcome the benefits. The results reported in the present paper are believed to be useful for the thermal optimization of nanofluids flow inside tubes. - Highlights: • Turbulent convection of Al2O3-water nanofluid is investigated. • Mixture model is employed in the numerical analysis. • A performance analysis is developed by analyzing entropy generation and PEC

  1. Computational study of twisted-tape-induced swirl flow heat transfer and pressure drop in a vertical circular tube under velocities controlled

    International Nuclear Information System (INIS)

    Highlights: • Measure turbulent heat transfer coefficients in a pipe with twisted-tape insert. • Use a Pt pipe of 6 mm ID and a SUS304 twisted-tape with twist ratio of 3.39. • Solve numerically turbulent heat transfer in a pipe with twisted-tape insert. • Numerical solutions are in good agreement with experimental data. • Clarify thickness of conductive sub-layer in a pipe with twisted-tape insert. -- Abstract: The twisted-tape-induced swirl flow heat transfer due to exponentially increasing heat inputs with various exponential periods and twisted-tape-induced pressure drop were systematically measured with mass velocity G = 4120 to 13 570 kg/m2/s, inlet liquid temperature Tin = 300.13 to 305.78 K and inlet pressure Pin = 866.52 to 945.86 kPa by an experimental water loop flow. Measurements were made on a 59.2 mm effective length and its three sections (upper, mid and lower positions), which were spot-welded four potential taps on the outer surface of a 6 mm inner diameter, a 69.6 mm heated length and a 0.4 mm thickness of Platinum circular test tube with the twisted-tape insert. The SUS304 twisted-tape of width w = 5.6 mm, thickness δT = 0.6 mm, total length l = 372 mm, pitch of 180° rotation H = 20.34 mm and twist ratio y = H/d = 3.39 was employed in this work. On the other hand, theoretical equations for k–ε turbulence model in a circular tube of a 6 mm in diameter and a 636 mm long with the twisted-tape insert were numerically solved for heating of water with heated section of a 6 mm in diameter and a 70 mm long by using PHOENICS code under the same conditions as the experimental ones considering the temperature dependence of thermo-physical properties concerned. The twisted-tape of w = 5.6 mm, δT = 0.6 mm, l = 370 mm, H = 20 mm and y = 3.33 was installed under the same experimental position. The surface heat flux q and the average surface temperature Ts,av on the circular tube with the twisted-tape of y = 3.33 obtained theoretically were

  2. Scientific Animations for Tsunami Hazard Mitigation: The Pacific Tsunami Warning Center's YouTube Channel

    Science.gov (United States)

    Becker, N. C.; Wang, D.; Shiro, B.; Ward, B.

    2013-12-01

    Outreach and education save lives, and the Pacific Tsunami Warning Center (PTWC) has a new tool--a YouTube Channel--to advance its mission to protect lives and property from dangerous tsunamis. Such outreach and education is critical for coastal populations nearest an earthquake since they may not get an official warning before a tsunami reaches them and will need to know what to do when they feel strong shaking. Those who live far enough away to receive useful official warnings and react to them, however, can also benefit from PTWC's education and outreach efforts. They can better understand a tsunami warning message when they receive one, can better understand the danger facing them, and can better anticipate how events will unfold while the warning is in effect. The same holds true for emergency managers, who have the authority to evacuate the public they serve, and for the news media, critical partners in disseminating tsunami hazard information. PTWC's YouTube channel supplements its formal outreach and education efforts by making its computer animations available 24/7 to anyone with an Internet connection. Though the YouTube channel is only a month old (as of August 2013), it should rapidly develop a large global audience since similar videos on PTWC's Facebook page have reached over 70,000 viewers during organized media events, while PTWC's official web page has received tens of millions of hits during damaging tsunamis. These animations are not mere cartoons but use scientific data and calculations to render graphical depictions of real-world phenomena as accurately as possible. This practice holds true whether the animation is a simple comparison of historic earthquake magnitudes or a complex simulation cycling through thousands of high-resolution data grids to render tsunami waves propagating across an entire ocean basin. PTWC's animations fall into two broad categories. The first group illustrates concepts about seismology and how it is critical to

  3. Entropy generation analysis of turbulent convection flow of Al2O3–water nanofluid in a circular tube subjected to constant wall heat flux

    International Nuclear Information System (INIS)

    Highlights: • An optimization methodology for nanofluids based on entropy generation is proposed. • Both concentration and particle dimensions are taken into account. • Constant Re, velocity and mass flow inlet conditions are investigated. • Optimal working conditions are determined for the different cases. - Abstract: A parametric investigation of entropy generation of nanofluid turbulent forced convection inside a circular section tube subjected to constant wall heat flux is presented. The analysis is developed for different inlet conditions (i.e. constant Re, fixed mass flow rate and constant velocity) and in a concentration range from 0% up to 6%. The impact of the dispersed nanoparticles on total, thermal and frictional entropy generation is investigated and optimal working conditions are highlighted. The study shows that at the increase of Re, the optimal particles concentration to minimize entropy generation decreases. The impact of nanoparticles dimension is also taken into account, showing that its effect depends on the flow conditions. When working with constant mass flow rate, an optimal concentration is determined to minimize the frictional entropy generation, whereas thermal entropy generation results to increase. The study shows that to minimize total entropy generation when velocity is kept constant, a low concentration of nanoparticles is necessary

  4. Numerical analysis of mass transfer with graphite oxidation in a laminar flow of multi-component gas mixture through a circular tube

    International Nuclear Information System (INIS)

    In the present paper, mass transfer has been numerically studied in a laminar flow through a circular graphite tube to evaluate graphite corrosion rate and generation rate of carbon monoxide during a pipe rupture accident in a high temperature gas cooled reactor. In the analysis, heterogeneous (graphite oxidation and graphite/carbon dioxide reaction) and homogeneous (carbon monoxide combustion) chemical reactions were dealt in the multi-component gas mixture; helium, oxygen, carbon monoxide and carbon dioxide. Multi-component diffusion coefficients were used in a diffusion term. Mass conservation equations of each gas component, mass conservation equation and momentum conservation equations of the gas mixture were solved by using SIMPLE algorism. Chemical reactions between graphite and oxygen, graphite and carbon dioxide, and carbon monoxide combustion were taken into account in the present numerical analysis. An energy equation for the gas mixture was not solved and temperature was held to be constant in order to understand basic mass transfer characteristics without heat transfer. But, an energy conservation equation for single component gas was added to know heat transfer characteristics without mass transfer. The effects of these chemical reactions on the mass transfer coefficients were quantitatively and qualitatively clarified in the range of 50 to 1000 of inlet Reynolds numbers, 0 to 0.5 of inlet oxygen mass fraction and 800 to 1600degC of temperature. (author)

  5. Study on heat transfer and friction factor characteristics of γ-Al2O3/water through circular tube with twisted tape inserts with different thicknesses

    International Nuclear Information System (INIS)

    An experimental study was carried out to investigate heat transfer and friction factor characteristics of γ-Al2O3/water nano-fluid through circular tube with twisted tape inserts with various thicknesses at constant heat flux. In this work, γ-Al2O3/water nano-fluids with two volume concentrations of 0.5% and 1% were used as the working fluid. The twist ratio of twisted tape remained constant at 3.21, while the thicknesses were changed through three values of 0.5 mm, 1 mm and 2 mm. The experiments were performed in laminar flow regime from 150 to 1600 Reynolds numbers. Results indicated that twisted tape inserts enhanced the average convective heat transfer coefficient, and also more the thickness of twisted tape is more the enhancement of convective heat transfer coefficient is. Also, the highest enhancement was achieved at maximum volume concentration. Results showed that nano-fluids have better heat transfer performance when utilized with thicker twisted tapes. At the same time, the increase in twisted tape thickness leads to an increase in friction factor. In the end, the combined results of these two phenomena result in enhanced convective heat transfer coefficient and thermal performance. Finally, two new correlations were offered for Nusselt number and thermal performance based on our experimental observation. (authors)

  6. FE SIMULATION OF CENTER CRACK OCCURRENCE IN TUBE ROUNDS DURING TWO-ROLL ROTARY ROLLING PROCESS

    Institute of Scientific and Technical Information of China (English)

    S.Z. Li; J. Xu; Y.D. Yin; J.G. Xue; F. Pan; J.M. Zheng; J.H. Yoon

    2007-01-01

    With the aid of FE(finite element) code MSC.Superform 2005, 2-D coupled thermo-mechanical simulation of center-crack occurrence in round billet during 2-roll rotary rolling process was presented using Oyane ductile fracture criteria. A simple modeling is put forward based on the spiral motion of the workpiece as an essential characteristic in movement. The influence of the feed angle and the entry cone angle of the main roll on the process was taken into account in the modeling. The soundness for simplifying the 3-D rotary rolling into a 2-D problem was discussed. By adopting the parameters of Diescher piercer in 140mm mandrel mill of Bao Steel, the distribution and development of strain/stress were analyzed, and the eigen value of ductile fracture as well. The critical percentage of diameter reduction was obtained from the simulation. The result showed a good agreement with the experimental value, and therefore was of widely guiding significance to the practical process for rationally formulating the deformation parameters of steel tube piercing.

  7. Administrative Circulars

    CERN Multimedia

    Département des Ressources humaines

    2004-01-01

    Administrative Circular N° 2 (Rev. 2) - May 2004 Guidelines and procedures concerning recruitment and probation period of staff members This circular has been revised. It cancels and replaces Administrative Circular N° 2 (Rev. 1) - March 2000. Administrative Circular N° 9 (Rev. 3) - May 2004 Staff members contracts This circular has been revised. It cancels and replaces Administrative Circular N° 9 (Rev. 2) - March 2000. Administrative Circular N° 26 (Rev. 4) - May 2004 Procedure governing the career evolution of staff members This circular has also been revised. It Administrative Circulars Administrative Circular N° 26 (Rev. 3) - December 2001 and brings up to date the French version (Rev. 4) published on the HR Department Web site in January 2004. Operational Circular N° 7 - May 2004 Work from home This circular has been drawn up. Operational Circular N° 8 - May 2004 Dealing with alcohol-related problems...

  8. The C-seal trial: colorectal anastomosis protected by a biodegradable drain fixed to the anastomosis by a circular stapler, a multi-center randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Bakker Ilsalien S

    2012-11-01

    Full Text Available Abstract Background Anastomotic leakage is a major complication in colorectal surgery and with an incidence of 11% the most common cause of morbidity and mortality. In order to reduce the incidence of anastomotic leakage the C-seal is developed. This intraluminal biodegradable drain is stapled to the anastomosis with a circular stapler and prevents extravasation of intracolonic content in case of an anastomotic dehiscence. The aim of this study is to evaluate the efficacy of the C-seal in reducing anastomotic leakage in stapled colorectal anastomoses, as assessed by anastomotic leakage leading to invasive treatment within 30 days postoperative. Methods The C-seal trial is a prospective multi-center randomized controlled trial with primary endpoint, anastomotic leakage leading to re-intervention within 30 days after operation. In this trial 616 patients will be randomized to the C-seal or control group (1:1, stratified by center, anastomotic height (proximal or distal of peritoneal reflection and the intention to create a temporary deviating ostomy. Interim analyses are planned after 50% and 75% of patient inclusion. Eligible patients are at least 18 years of age, have any colorectal disease requiring a colorectal anastomosis to be made with a circular stapler in an elective setting, with an ASA-classification Discussion This Randomized Clinical trial is designed to evaluate the effectiveness of the C-seal in preventing clinical anastomotic leakage. Trial registration NTR3080

  9. Online inspection of circular fluorescent lamp

    Science.gov (United States)

    Ang, Beng-Hoe

    1998-10-01

    One step in the manufacture of circular fluorescent lamps is the mercury (Hg) injection process in which a small amount of mercury approximately 20 mg is injected into the fluorescent tube. An on-line detection of mercury is required to ensure that the amount of mercury residual inside the tube is within the acceptable tolerance. This critical operation is to reduce manufacturing overhead by controlling cost and reducing waste of materials. In view of this, an attempt has been made to design and develop an on- line mercury detection system with important benefits to the manufacturers, such as increased throughput, accuracy, reliability and consistency. This paper presents the configuration and development works of the on-line circular fluorescent lamp inspection system developed by Industrial Project Group--Machine Vision Center of Nanyang Polytechnic. The inspection system performs on-line detection of mercury particles (Hg) inside the circular fluorescent lamp. Taking the orientation and translation offsets of the lamp into consideration, it detects the presence/absence as well as the size of the injected mercury. The system has been successfully operating 15 hours per day and inspecting more than 22 thousands lamps in the production plant.

  10. CFD Simulation of Heat Transfer and Friction Factor Augmentation in a Circular Tube Fitted with Elliptic-Cut Twisted Tape Inserts

    Directory of Open Access Journals (Sweden)

    Sami D. Salman

    2013-01-01

    Full Text Available This paper presents the application of a mathematical model for simulation of the swirling flow in a tube induced by elliptic-cut and classical twist tape inserts. Effects of the twist ratio (y=2.93, 3.91, and 4.89 and cut depth (w=0.4, 0.8, and 1.4 cm on heat transfer enhancement (Nu and friction factor (f in laminar flow are numerically investigated. The simulation is carried out using commercial CFD package (FLUENT-6.3.26 to grasp the physical behaviour of the thermal and fluid flows of a constant heat-fluxed tube fitted with elliptic-cut twist tape in the laminar flow regime for the Reynolds number ranging from 200 to 2100. The simulated results matched the literature correlations of plain tube for validation with 8% variation for Nusselt number and 10% for friction factor. The results show that the heat transfer rate and friction factor in the tube equipped with elliptic-cut twist tape (ECT are significantly higher than those fitted with classical twist tape (CTT. Moreover the results also reveal that the Nusselt number and the friction factor in the tube with elliptic-cut twisted tape (ECT increase with decreasing twist ratios (y and cut depths (w.

  11. Information Circulars

    International Nuclear Information System (INIS)

    Information circulars are published from time to time under the symbol INFCIRC/. . . . for the purpose of bringing matters of general interest to the attention of all Members of the Agency. A list of the circulars which were of current interest on 15 January 1969 is given below, followed by an index to their subject matter. Other circulars can be traced by reference to earlier issues of the present document.

  12. Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full -- Part 4: Venturi tubes

    CERN Document Server

    International Organization for Standardization. Geneva

    2003-01-01

    ISO 5167-4:2003 specifies the geometry and method of use (installation and operating conditions) of Venturi tubes when they are inserted in a conduit running full to determine the flowrate of the fluid flowing in the conduit. ISO 5167-4:2003 also provides background information for calculating the flow-rate and is applicable in conjunction with the requirements given in ISO 5167-1. ISO 5167-4:2003 is applicable only to Venturi tubes in which the flow remains subsonic throughout the measuring section and where the fluid can be considered as single-phase. In addition, each of these devices can only be used within specified limits of pipe size, roughness, diameter ratio and Reynolds number. ISO 5167-4:2003 is not applicable to the measurement of pulsating flow. It does not cover the use of Venturi tubes in pipes sized less than 50 mm or more than 1 200 mm, or for where the pipe Reynolds numbers are below 20 000. ISO 5167-4:2003 deals with the three types of classical Venturi tubes: cast, machined and rough welde...

  13. Information circulars

    International Nuclear Information System (INIS)

    Information circulars are published from time to time under the symbol INFCIRC/... for the purpose of bringing matters of general interest to the attention of all Members of the Agency. The present revision contains INFCIRCs published up to mid-August 1994. A complete numerical list of information circulars is reproduced with their titles in the Annex

  14. Information circulars

    International Nuclear Information System (INIS)

    The document summarizes the Information Circulars published by the IAEA for the purpose of bringing matters of general interest to the attention of all Members of the Agency. This revision contains INFCIRCs published up to mid-August 1992. A complete numerical lift of Information Circulars with their titles is reproduced in an Annex

  15. Information circulars

    International Nuclear Information System (INIS)

    The document summarizes the Information Circulars published by the IAEA for the purpose of bringing matters of general interest to the attention of all Member States. This revision contains INFCIRCs published up to the end of May 1999, grouped by field of activity. A complete list of information circulars in numerical order is given in an annex

  16. Information Circulars

    International Nuclear Information System (INIS)

    Information circulars are published from time to time under the symbol INFCIRC/. for the purpose of bringing matters of general interest to the attention of all Members of the Agency. A list of the circulars that were current on 31 December 1964 is given, followed by an index to their subject matter.

  17. Information circulars

    International Nuclear Information System (INIS)

    The document summarizes the Information Circulars published by the IAEA for the purpose of bringing matters of general interest to the attention of all Member States. This revision contains INFCIRCs published up to February 1997, grouped by field of activity. A complete list of information circulars in numerical order is given in an annex

  18. Information circulars

    International Nuclear Information System (INIS)

    Information circulars are published from time to time under the symbol INFCIRC/... for the purpose of bringing matters of general interest to the attention of all Members of the Agency. The present revision contains INFCIRCs published up to the end of April 2002. A complete numerical list of information circulars is reproduced with their titles in the Annex

  19. 75 FR 32911 - Preliminary Results of Antidumping Duty Administrative Review: Circular Welded Carbon Steel Pipes...

    Science.gov (United States)

    2010-06-10

    ... Welded Carbon Steel Pipes and Tubes From Taiwan AGENCY: Import Administration, International Trade... administrative review of the antidumping duty order on circular welded carbon steel pipes and tubes from Taiwan... circular welded carbon steel pipes and tubes from Taiwan. See Certain Circular Welded Carbon Steel...

  20. 76 FR 33210 - Preliminary Results of Antidumping Duty Administrative Review: Circular Welded Carbon Steel Pipes...

    Science.gov (United States)

    2011-06-08

    ... Welded Carbon Steel Pipes and Tubes From Taiwan AGENCY: Import Administration, International Trade... administrative review of the antidumping duty order on circular welded carbon steel pipes and tubes from Taiwan... circular welded carbon steel pipes and tubes from Taiwan. See Certain Circular Welded Carbon Steel...

  1. Circular Updates

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Circular Updates are periodic sequentially numbered instructions to debriefing staff and observers informing them of changes or additions to scientific and specimen...

  2. Information circulars

    International Nuclear Information System (INIS)

    The document summarizes the information circulars published by the IAEA for the purpose of bringing matters of general interest to the attention of all Members of the Agency. In the main body of the document only those documents which are regarded as likely to be of current interest are listed. A complete numerical list of information circulars with their titles is reproduced in the Annex

  3. Ultrasonography for Proper Endotracheal Tube Placement Confirmation in Out-of-hospital Cardiac Arrest Patients: Two-center Experience

    Directory of Open Access Journals (Sweden)

    Jen-Tang Sun

    2014-06-01

    Conclusion: Real-time tracheal ultrasonography is an accurate method for identifying endotracheal tube position during cardiopulmonary resuscitation without the need for interruption of chest compression.

  4. Mechanical behavior and bearing capacity calculation of recycled aggregate concrete-filled circular steel tube columns under eccentric loading%钢管再生混凝土偏压柱受力性能及承载力计算

    Institute of Scientific and Technical Information of China (English)

    陈宗平; 李启良; 张向冈; 薛建阳; 陈宝春

    2012-01-01

    To study the mechanical behavior of recycled aggregate concrete-filled circular steel tube(RACFCST) columns under eccentric loading,15 specimens with different replacement ratio of recycled coarse aggregate,slenderness ratio and eccentricity were tested under the monotonic static loading.The failure modes were observed,and then the curve of the entire loading process as well as the strain distribution over the cross section were obtained.The influence of varying parameters on the mechanical behavior of RACFCST columns was analyzed,and then the ultimate bearing capacity was calculated using existing theories.It is shown that about the failure process and failure mode RACFCST columns are similar to the eccentrically loaded concrete-filled circular steel tube columns,in which the circular steel tube fails eventually in the drum-like buckling mode.It is found that RACFCST columns have high bearing capacity and good deformation performance,and the influences of eccentricity and slenderness ratio on the mechanical behavior of RACFCST columns are obvious,while the influence of aggregate replacement ratio is comparatively unobvious.%为了研究钢管再生混凝土偏压柱的受力性能,设计15个试件进行静力单调加载试验,考虑了再生粗骨料取代率、长细比和偏心距3个变化参数。观察试件的破坏形态,获取试件受力的全过程曲线,给出截面应变的分布情况,分析各变化参数对钢管再生混凝土偏压柱受力性能的影响,利用相关理论方法计算钢管再生混凝土偏压柱的极限承载能力。研究结果表明:钢管再生混凝土偏压柱与普通钢管混凝土偏压柱的受力过程及破坏形态相似,钢管最终表现为鼓曲破坏;钢管再生混凝土偏压柱具有较高的承载能力和良好的变形性能;偏心距、长细比对钢管再生混凝土偏压柱的受力性能影响显著,而再生粗骨料取代率对其影响不大。

  5. Operational Circulars

    CERN Document Server

    2003-01-01

    Operational Circular N° 4 - April 2003 Conditions for use by members of the CERN personnel of vehicles belonging to or rented by CERN - This circular has been drawn up. Operational Circular N° 5 - October 2000 Use of CERN computing facilities - Further details on the personal use of CERN computing facilities Operational Circular N° 5 and its Subsidiary Rules http://cern.ch/ComputingRules defines the rules for the use of CERN computing facilities. One of the basic principles governing such use is that it must come within the professional duties of the user concerned, as defined by the user's divisional hierarchy. However, personal use of the computing facilities is tolerated or allowed provided : a) It is in compliance with Operational Circular N° 5 and not detrimental to official duties, including those of other users; b) the frequency and duration is limited and there is a negligible use of CERN resources; c) it does not constitute a political, commercial and/or profit-making activity; d) it is not...

  6. 微重力下圆管毛细流动解析近似解研究%The analytical approximate solutions of capillary flow in circular tubes under microgravity∗

    Institute of Scientific and Technical Information of China (English)

    李永强; 张晨辉; 刘玲; 段俐; 康琦

    2013-01-01

      应用同伦分析法研究微重力环境下圆管毛细流动解析近似解问题,给出了级数解的表达公式。不同于其他解析近似方法,该方法从根本上克服了摄动理论对小参数的过分依赖,其有效性与所研究的非线性问题是否含有小参数无关,适用范围广。同伦分析法提供了选取基函数的自由,可以选取较好的基函数,更有效地逼近问题的解,通过引入辅助参数和辅助函数来调节和控制级数解的收敛区域和收敛速度,同伦分析法为圆管毛细流动问题的解析近似求解开辟了一个全新的途径。通过具体算例,将同伦分析法与四阶龙格库塔方法数值解做了比较,结果表明,该方法具有很高的计算精度。%The capillary flow in a circular tube under microgravity environment is investigated by the homotopy analysis method (HAM), and the approximate analytical solution in the form of series solution is obtained. Different from other analytical approximate methods, the HAM is totally independent of small physical parameters, and thus it is suitable for most nonlinear problems. The HAM provides us a great freedom to choose basis functions of solution series, so that a nonlinear problem can be approximated more effectively, and it adjusts and controls the convergence region and the convergence rate of the series solution through introducing auxiliary parameter and the auxiliary function. The HAM hews out a new approach to the analytical approximate solutions of capillary flow in a circular tube. Through the specific example and comparing homotopy approximate analytical solution with the numerical solution which is obtained by the fourth-order Runge-Kutta method, the computed result indicate that this method has the good computational accuracy.

  7. Experimental study of the effects of flow acceleration and buoyancy on heat transfer in a supercritical fluid flow in a circular tube

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Eok [Department of Mechanical Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Namgu, Pohang, Kyungbuk 790-784 (Korea, Republic of); Kim, Moo Hwan, E-mail: mhkim@postech.ac.k [Department of Mechanical Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Namgu, Pohang, Kyungbuk 790-784 (Korea, Republic of)

    2010-10-15

    Experiments on turbulent heat transfer by supercritical CO{sub 2} in a vertical upward flow were conducted in a tube with an inner diameter of 4.5 mm. The experiments were performed for bulk fluid temperatures ranging from 29 to 115 {sup o}C, pressures ranging from 74.6 to 102.6 bar, local wall heat fluxes ranging from 38 to 234 kW/m{sup 2}, and mass fluxes ranging from 208 to 874 kg/m{sup 2} s. The wall temperature distributions were significantly influenced by wall heat flux and mass flux. The wall temperature had a noticeable peak value when the wall heat flux was moderate and the mass flux was low. To determine the buoyancy and flow acceleration effects on heat-transfer characteristics, the ratios of the Nusselt numbers obtained from the experimental data and from a reference correlation are compared with Bo* and q{sup +} along the test section. To analyze the changes in the shear stress distribution due to flow acceleration and buoyancy effects, the ratios of the shear stress reduction to wall shear stress due to flow acceleration and buoyancy effects are derived from approximate considerations. A new heat-transfer correlation is proposed, which could be used to predict heat transfer phenomena in a vertical upward flow of a supercritical fluid. The correlation is assessed by comparison with various experimental data.

  8. ADVANCE IN HIGH-STRENGTH CONCRETE FILLED SQUARE STEEL TUBULAR STRUCTURE WITH INNER CFRP CIRCULAR TUBE%内置CFRP圆管的方钢管高强混凝土结构研究进展

    Institute of Scientific and Technical Information of China (English)

    李帼昌; 张春雨; 于洪平

    2012-01-01

    该文进行了内置CFRP圆管的方钢管高强混凝土结构的轴压短柱、轴压中长柱、轴压长柱、纯弯构件、单向偏压短柱、单向偏压中长柱、双向偏压短柱、双向偏压中长柱的试验研究和有限元模拟,分析了内置CFRP圆管的方钢管高强混凝土结构各类基本构件的受力全过程以及破坏模式,并提出了用于计算该结构各类基本构件的承载力以及变形的计算公式.在试验研究和数值模拟的基础上,将此种新型组合结构构件的力学性能与方钢管混凝土构件的力学性能进行了比较分析.%Plentiful experiment researches and the finite element analysis are performed on short and slender columns under axial compression beams, short columns and slender columns under eccentric compression, short columns and slender columns of high-strength concrete filled square steel tube with inner CFRP circular tube under bi-axial eccentric compression. The failure mode and the mechanism of all kinds of members in an entire process are analyzed. And a simplified formula calculating the bearing capacity for each member is proposed. On the basis of above, the comparison between this new composite structure and a traditional concrete filled square steel tubular structure is done.

  9. Information circulars

    International Nuclear Information System (INIS)

    The document summarizes the Information Circulars published by the IAEA under the symbol INFCIRC/ for the purpose of bringing matters of general interest to the attention of all Members of the Agency. A complete list of INFCIRCs in numerical order with their titles is given in the Annex

  10. Experimental Study on Heat Transfer to Supercritical Water Flowing in Circular Tubes%圆管内超临界水上升、下降流动传热实验研究

    Institute of Scientific and Technical Information of China (English)

    赵萌; 李虹波; 张戈; 顾汉洋; 王磊; 程旭

    2012-01-01

    在SWAMUP实验回路中,针对超临界水流动换热开展上升、下降流实验研究,观测到了正常传热、传热恶化、传热强化等现象.实验结果及分析表明:浮升效应导致的第一类传热恶化只会发生在上升流中,加速效应导致的第二类传热恶化与流动方向无关;表征浮升效应和加速效应无量纲参数Bu和πA能较好地从机理上预测第一类、第二类传热恶化.%The experimental studies on heat transfer to supercritical water flowing upward and downward in circular tubes were carried out at the SWAMUP test facility, and the phenomena of normal heat transfer, heat transfer deterioration (HTD) and enhancement heat transfer were recorded. Test results show that HTD caused by buoyancy effect only appears in upward flow and HTD caused by acceleration effect appears both in upward flow and downward flow. In addition, several dimensionless numbers which widely apply in heat transfer correlations are assessed. It is concluded that the dimensionless number Bu and ka show unique effect on heat transfer coefficient.

  11. Crushing characteristics of composite tubes with 'near-elliptical' cross sections

    Science.gov (United States)

    Farley, Gary L.; Jones, Robert M.

    1992-01-01

    An experimental investigation was conducted to determine whether the energy-absorption capability of near-elliptical cross-section composite tubular specimens is a function of included angle. Each half of the near-elliptical cross-section tube is a segment of a circle. The included angle is the angle created by radial lines extending from the center of the circular segment to the ends of the circular segment. Graphite- and Kevlar-reinforced epoxy material was used to fabricate specimens. Tube internal diameters were 2.54, 3.81, and 7.62 cm, and included angles were 180, 160, 135, and 90 degrees. Based upon the test results from these tubes, energy-absorption capability increased between 10 and 30 percent as included angle decreased between 180 and 90 degrees for the materials evaluated. Energy-absorption capability was a decreasing nonlinear function of the ratio of tube internal diameter to wall thickness.

  12. ADMINISTRATIVE CIRCULARS

    CERN Multimedia

    Division des ressources humaines

    2000-01-01

    N° 2 (Rev. 1) - March 2000Guidelines and procedures concerning recruitment and probation period of staff membersN° 9 (Rev. 2) - March 2000Staff members contractsN° 16 (Rev. 2) - January 2000TrainingN° 30 (Rev. 1) - January 2000Indemnities and reimbursements upon taking up appointment and termination of contractN° 32 - February 2000Principles and procedures governing complaints of harassmentThese circular have been amended (No 2, N° 9, N° 16 and N° 30) or drawn up (N° 32).Copies are available in the Divisional Secretariats.Note:\tAdministrative and operational circulars, as well as the lists of those in force, are available for consultation in the server SRV4_Home in the Appletalk zone NOVELL (as GUEST or using your Novell username and password), volume PE Division Data Disk.The Word files are available in the folder COM, folder Public, folder ADM.CIRC.docHuman Resources DivisionTel. 74128

  13. 小规格管坯电弧式中心孔机的试制%Trial Production of Small Size Tube Arc Center Hole Machine

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

      冷拔无缝钢管的壁厚偏差是评定其质量优劣的重要指标,而管坯中心孔的加工是减少壁厚偏差的重要保证。为了解决硬质材料管坯上难于打中心孔的问题,提出一种基于电弧式中心孔机的设计方法。介绍了该机的组成和原理。实际生产表明,该机减小了穿孔毛管壁厚偏差,提高了毛管的质量。%Pipe thickness deviation of cold-drawn seamless steel pipe is an important index to evaluate the quali⁃ty of pipe. Processing a tube center hole is an important guarantee for the reduction of pipe thickness deviation. In order to solve the problem of centering the hard material tube, this paper presents an arc hole center based on machine design method. The paper introduces the characteristics of the machine components and principle. The actual production shows that the machine reduces the pierced shell pipe thickness deviation, and improves the quality of the capillary.

  14. Hollow circular-truncated cone resonator and its hollow variable biconical laser beam

    Science.gov (United States)

    Liu, Jinglun; Chen, Mei; Wang, Qionghua; Sun, Nianchun

    2014-05-01

    To obtain a hollow variable biconical laser beam (HVBLB), a CO2 laser having a hollow circular-truncated cone resonator (HCTCR) is presented. This HCTCR comprises a rotationally symmetric total-reflecting concave mirror at the bottom, a rotationally symmetric part-reflecting convex mirror at the top, and a hollow circular-truncated cone discharge tube at the middle. The cross section of this generated biconical laser beam changes from annulus to circular to annulus and the size of this cross section from big to small to large as the propagation distance increases. So, a kind of laser beam with variable center intensity from zero to peak value to zero is obtained and is known as HVBLB. Due to the inclusion of part of the hollow laser beam (HLB) and solid laser beam, this HVBLB requires no additional beam-shaping element and has broad applications such as optical trapping and commercial manufacturing.

  15. The C-seal trial: colorectal anastomosis protected by a biodegradable drain fixed to the anastomosis by a circular stapler, a multi-center randomized controlled trial

    OpenAIRE

    Bakker Ilsalien S; Morks Annelien N; Hoedemaker Henk O ten Cate; Burgerhof Johannes G M; Leuvenink Henri G; Ploeg Rutger J; Havenga Klaas

    2012-01-01

    Abstract Background Anastomotic leakage is a major complication in colorectal surgery and with an incidence of 11% the most common cause of morbidity and mortality. In order to reduce the incidence of anastomotic leakage the C-seal is developed. This intraluminal biodegradable drain is stapled to the anastomosis with a circular stapler and prevents extravasation of intracolonic content in case of an anastomotic dehiscence. The aim of this study is to evaluate the efficacy of the C-seal in red...

  16. Experimental Study of Mechanical Behavior of Spatial Circular Steel Tube Truss and Concrete Composite Girder%空间圆管桁架混凝土组合梁受力性能试验研究

    Institute of Scientific and Technical Information of China (English)

    陈建兵; 陈荣; 李强

    2014-01-01

    空间圆管桁架混凝土组合结构是一种新型组合结构,为了解其受力特点、破坏机理、变形能力、管桁架杆件的内力分布规律及界面相对滑移等,设计制作了2根弦杆未填充混凝土的不同混凝土翼板厚度的空间圆管桁架混凝土组合梁模型试件,采用三分点对称加载,对其进行受力性能试验研究。研究表明,在对称荷载作用下,组合梁的破坏形式为弯曲破坏,同时伴随有受拉腹杆节点焊缝的强度破坏;空间圆管桁架组合梁具有良好的承载能力和变形能力,相同荷载下,混凝土板厚的组合梁的承载能力高于板薄的组合梁;组合梁破坏时,其跨中挠度约为跨径的1/200;不考虑界面相对滑移的情况下,截面应变满足平截面假定;加载前期,支点截面界面相对滑移量大于 L/8截面,而加载后期,L/8截面界面相对滑移量大于支点截面;腹杆为非轴心受拉或受压杆件,且跨中位置腹杆的轴力较小,梁端位置腹杆的轴力较大。%The spatial steel truss of circular steel tubes and concrete composite structure is a new type of composite structure .In order to examine its load bearing behavior ,failure mechanism , deformability ,internal force distribution law of tubular truss members and interface relative slip -page ,a spatial steel truss of circular tubes and concrete composite girder model was designed and fabricated .The model was characterized by its two chords that are not filled with concrete as well as the concrete flange plates with variable thickness .Loads were symmetrically applied at the 1/3 and 2/3 locations of the calculated span length of the girder proposed .The mechanical behavior of the model was experimentally studied .The results of the study indicate that under the action of symmetric loads ,the composite girder succumbs to bending failure ,concurrently with strength damage at the welding joints of the tensile web

  17. Reconfigurable Plasma Antenna Array by Using Fluorescent Tube for Wi-Fi Application

    OpenAIRE

    H. Ja’afar; M. T. Ali; Dagang, A N; I. P. Ibrahim; N. A. Halili; H. M. Zali

    2016-01-01

    This paper presents a new design of reconfigurable plasma antenna array using commercial fluorescent tube. A round shape reconfigurable plasma antenna array is proposed to collimate beam radiated by an omnidirectional antenna (monopole antenna) operates at 2.4GHz in particular direction. The antenna design is consisted of monopole antenna located at the center of circular aluminum ground. The monopole antenna is surrounded by a cylindrical shell of conducting plasma. The plasma shield consist...

  18. Flow and heat transfer characteristics of falling water film on horizontal circular and non-circular cylinders

    Institute of Scientific and Technical Information of China (English)

    LUO Lin-cong; ZHANG Guan-min; PAN Ji-hong; TIAN Mao-cheng

    2013-01-01

    This paper presents a two-dimensional CFD study of the falling film evaporation of horizontal tubes with different shapes applied in the seawater desalination.The flow and heat transfer characteristics of the falling water film on one circular tube and two non-circular shaped tubes,a drop-shaped tube and an oval-shaped tube,are analyzed,respectively.The Volume Of Fluid (VOF)method is employed to investigate the influence of the mass flow rate and the feeder height on the distribution of the film thickness and the heat transfer performance.The numerical results show that the minimum value of the film thickness appears approximately at the angular positions of 125°,160° and 170° for the smooth circular,oval-and drop-shaped tubes,respectively.The film thickness grows with the increase of the mass flow rate and the decrease of the feeder height,while the variation pattern varies for different tubes.Moreover,compared with the circular tube,the drop-and oval-shaped tubes have a lower dimensionless temperature and a thinner thermal boundary layer,which means a better heat transfer performance.Finally,the numerical results correlate well with the experimental and predicted data in literature.

  19. Circularity and Lambda Abstraction

    DEFF Research Database (Denmark)

    Danvy, Olivier; Thiemann, Peter; Zerny, Ian

    2013-01-01

    In this tribute to Doaitse Swierstra, we present the rst transformation between lazy circular programs a la Bird and strict cir- cular programs a la Pettorossi. Circular programs a la Bird rely on lazy recursive binding: they involve circular unknowns and make sense equa- tionally. Circular...... unknowns from what is done to them, which we lambda-abstract with functions. The circular unknowns then become dead variables, which we eliminate. The result is a strict circu- lar program a la Pettorossi. This transformation is reversible: given a strict circular program a la Pettorossi, we introduce...

  20. Experimental study of thermal–hydraulic performance of cam-shaped tube bundle with staggered arrangement

    International Nuclear Information System (INIS)

    Highlights: • Thermal–hydraulic performance of a non-circular tube bundle has been investigated experimentally. • Tubes were mounted in staggered arrangement with two longitudinal pitch ratios 1.5 and 2. • Drag coefficient and Nusselt number of tubes in second row was measured. • Friction factor of this tube bundle is lower than circular tube bundle. • Thermal–hydraulic performance of this tube bundle is greater than circular tube bundle. - Abstract: Flow and heat transfer from cam-shaped tube bank in staggered arrangement is studied experimentally. Tubes were located in test section of an open loop wind tunnel with two longitudinal pitch ratios 1.5 and 2. Reynolds number varies in range of 27,000 ⩽ ReD ⩽ 42,500 and tubes surface temperature is between 78 and 85 °C. Results show that both drag coefficient and Nusselt number depends on position of tube in tube bank and Reynolds number. Tubes in the first column have maximum value of drag coefficient, while its Nusselt number is minimum compared to other tubes in tube bank. Moreover, pressure drop from this tube bank is about 92–93% lower than circular tube bank and as a result thermal–hydraulic performance of this tube bank is about 6 times greater than circular tube bank

  1. Circular-rubbing Manipulation

    Institute of Scientific and Technical Information of China (English)

    SHEN Guo-quan; XIAO Yuan-chun

    2003-01-01

    @@ "Mo" literally means "rubbing between two things"and "eliminating". Circular-rubbing is one of the earliest manipulations used in clinical practice. Circular-rubbing differs from pressing actually. Pressing is a static manipulation and acts to inhibit motion; circular-rubbing is a movable manipulation and serves to eliminate stationary. Circular-rubbing can be performed by either the palm or the finger.

  2. Effect of tube size on electromagnetic tube bulging

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The commercial finite code ANSYS was employed for the simulation of the electromagnetic tube bulging process. The finite element model and boundary conditions were thoroughly discussed. ANSYS/EMAG was used to model the time varying electromagnetic field in order to obtain the radial and axial magnetic pressure acting on the tube. The magnetic pressure was then used as boundary conditions to model the high velocity deformation of various length tube with ANSYS/LSDYNA. The time space distribution of magnetic pressure on various length tubes was presented. Effect of tube size on the distribution of radial magnetic pressure and axial magnetic pressure and high velocity deformation were discussed. According to the radial magnetic pressure ratio of tube end to tube center and corresponding dimensionless length ratio of tube to coil, the free electromagnetic tube bulging was studied in classification. The calculated results show good agreements with practice.

  3. 海洋条件下竖直圆管内单相传热特性实验研究%Experimental Research on Single-Phase Heat Transfer Characteristics in a Vertical Circular Tube under Marine Conditions

    Institute of Scientific and Technical Information of China (English)

    杜思佳; 张虹; 贾宝山

    2011-01-01

    Experiments have been conducted to study the heat transfer characteristics of single-phase forced circulation when the test tube was under different marine conditions. The experiments measured the wall temperature of test tube to calculate the heat transfer coefficients at different circumferential places.When the test tube was under inclined conditions, the heat transfer coefficient increased at downside and decreased at upside of test tube because of buoyancy effect. When the test tube was under rolling conditions,the heat transfer coefficients fluctuated with the rolling motions, and the Coriolis force dominated the heat transfer fluctuation during the rolling motion. CFD method was used to simulate the heat transfer phenomena under marine conditions, and the results were accord to the experimental phenomena.%进行了海洋条件下圆管内的强迫循环传热实验,通过测量竖直圆管周向的温度分布,从而得到海洋条件下不同位置的传热系数.实验结果表明:倾斜时,靠近上侧管壁附近的传热减弱,而靠近下方的管壁处传热增强;摇摆时,垂直于摇摆轴方向的管壁处传热会发生周期性振荡.采用计算流体力学(CFD)方法对海洋条件下单相传热问题进行了数值模拟,计算结果与实验结果一致.分析结果表明:倾斜时影响传热的主要因素是浮力;摇摆时影响传热的最主要因素是科里奥利力.

  4. Eddy-Current Detection of Cracks in Tubes

    Science.gov (United States)

    Parent, R.; Kettering, D.

    1987-01-01

    Nondestructive device tests narrow, sharply-bent metal tubes. Eddycurrent probe detects incipient cracks inside small metal tubes. Tube-centering device consisting of pair of opposed bars ensures tube centered on eddy-current coil. Probe moves along length of bent tube to inspect repeatably for cracks. Compatible with tubes of different cross sections, oval, flattened, square, rectangular,or irregular. Adapts for inspecting formed tubes in petrochemical, automotive, nuclear, and medical equipment.

  5. PUBLICATION OF ADMINISTRATIVE CIRCULAR

    CERN Multimedia

    HR Department

    2008-01-01

    ADMINISTRATIVE CIRCULAR NO. 23 (REV. 2) – SPECIAL WORKING HOURS Administrative Circular No. 23 (Rev. 2) entitled "Special working hours", approved following discussion in the Standing Concertation Committee meeting of 9 December 2008, will be available on the intranet site of the Human Resources Department as from 19 December 2008: http://cern.ch/hr-docs/admincirc/admincirc.asp It cancels and replaces Administrative Circular No. 23 (Rev. 1) entitled "Stand-by duty" of April 1988. A "Frequently Asked Questions" information document on special working hours will also be available on this site. Paper copies of this circular will shortly be available in departmental secretariats. Human Resources Department Tel. 78003

  6. Publication of administrative circular

    CERN Multimedia

    HR Department

    2009-01-01

    ADMINISTRATIVE CIRCULAR NO. 23 (REV. 2) – SPECIAL WORKING HOURS Administrative Circular No. 23 (Rev. 2) entitled "Special working hours", approved following discussion in the Standing Concertation Committee on 9 December 2008, will be available on the intranet site of the Human Resources Department as from 19 December 2008: http://cern.ch/hr-docs/admincirc/admincirc.asp It cancels and replaces Administrative Circular No. 23 (Rev. 1) entitled "Stand-by duty" of April 1988. A "Frequently Asked Questions" information document on special working hours will also be available on this site. Paper copies of this circular will shortly be available in Departmental Secretariats. Human Resources Department Tel. 78003

  7. Toroidal circular dichroism

    Science.gov (United States)

    Raybould, T. A.; Fedotov, V. A.; Papasimakis, N.; Kuprov, I.; Youngs, I. J.; Chen, W. T.; Tsai, D. P.; Zheludev, N. I.

    2016-07-01

    We demonstrate that the induced toroidal dipole, represented by currents flowing on the surface of a torus, makes a distinct and indispensable contribution to circular dichroism. We show that toroidal circular dichroism supplements the well-known mechanism involving electric dipole and magnetic dipole transitions. We illustrate this with rigorous analysis of the experimentally measured polarization-sensitive transmission spectra of an artificial metamaterial, constructed from elements of toroidal symmetry. We argue that toroidal circular dichroism will be found in large biomolecules with elements of toroidal symmetry and should be taken into account in the interpretation of circular dichroism spectra of organics.

  8. The Circular Camera Movement

    DEFF Research Database (Denmark)

    Hansen, Lennard Højbjerg

    2014-01-01

    It has been an accepted precept in film theory that specific stylistic features do not express specific content. Nevertheless, it is possible to find many examples in the history of film in which stylistic features do express specific content: for instance, the circular camera movement is used...... circular camera movement. Keywords: embodied perception, embodied style, explicit narration, interpretation, style pattern, television style...

  9. Perfect Circular Dichroic Metamirrors

    CERN Document Server

    Wang, Zuojia; Liu, Yongmin

    2015-01-01

    In nature, the beetle Chrysina gloriosa derives its iridescence by selectively reflecting left-handed circularly polarized light only. Here, for the first time, we introduce and demonstrate the optical analogue based on an ultrathin metamaterial, which we term circular dichroic metamirror. A general method to design the circular dichroic metasmirror is presented under the framework of Jones calculus. It is analytically shown that the metamirror can be realized by two layers of anisotropic metamaterial structures, in order to satisfy the required simultaneous breakings of n-fold rotational (n>2) and mirror symmetries. We design an infrared metamirror, which shows perfect reflectance for left-handed circularly polarized light without reversing its handedness, while almost completely absorbs right-handed circularly polarized light. These findings offer new methodology to realize novel chiral optical devices for a variety of applications, including polarimetric imaging, molecular spectroscopy, as well as quantum ...

  10. 内置格构式圆钢管的T形型钢混凝土柱力学性能试验研究%EXPERIMENTAL RESEARCH ON MECHANICAL BEHAVIOR OF LATTICED CIRCULAR TUBES REINFORCED CONCRETE T-SHAPED COLUMNS

    Institute of Scientific and Technical Information of China (English)

    杨远龙; 杨华; 张素梅

    2013-01-01

    异形柱结构较传统框架结构能有效地改善建筑内部的使用空间,但目前应用较多的钢筋混凝土异形柱存在高轴压比下抗震性能不足,对水平荷载的方向性非常敏感等问题,其房屋高度和抗震设防烈度受到严格限制,制约了其在高设防烈度地区进一步的推广和应用.型钢混凝土异形柱相对于钢筋混凝土异形柱,其抗震性能有所改善,为此,该文提出了内部设置格构式圆钢管的T形型钢混凝土柱.进行了格构式型钢混凝土柱轴压、偏压和压弯滞回性能的三组系列试验,研究了上述试件的破坏模式与力学性能,分析了格构式型钢骨架的作用机理和对混凝土破坏模式的影响.试验结果表明,内部格构式型钢骨架能够保持整体工作,同时限制了型钢混凝土的粘结滑移,一定程度上延缓了混凝土的破坏.相对于钢筋混凝土试件,在轴压和偏压荷载工况下,型钢混凝土的承载力和延性显著提高;在压弯滞回荷载工况下,型钢混凝土的承载力和耗能性能得到改善.%Special-shaped column structures might improve residential architectural space effectively, compared with traditional frame structures. However, the widespread special-shaped reinforced concrete (RC) columns present insufficient aseismic behavior with a high axial load ratio and sensitivity to the horizontal loading direction, and have strict limitations in aseismic behaviors, in respect to applicable building height and aseismic fortification intensity, which hampers further generalization and application of special-shaped columns in a high aseismic fortification zone. Special-shaped steel reinforced concrete (SRC) columns behave advantages on the aseismic behaviors over special-shaped RC columns. A kind of T-shaped steel reinforced concrete column with latticed steel tubes in the sectional branch components is introduced. Three series of experimental investigations on the axial, eccentric

  11. 76 FR 36086 - Certain Circular Welded Non-Alloy Steel Pipe From Mexico: Final Results of Antidumping Duty...

    Science.gov (United States)

    2011-06-21

    ... Review: Certain Circular Welded Non-Alloy Steel Pipe and Tube from Mexico, 74 FR 41681 (August 18, 2009... Antidumping Duty Changed Circumstances Review: Certain Circular Welded Non-Alloy Steel Pipe from Mexico, 75 FR... Less Than Fair Value: Circular Welded Non- Alloy Steel Pipe From Mexico, 57 FR 42953 (September...

  12. Circular statistics in R

    CERN Document Server

    Pewsey, Arthur; Ruxton, Graeme D

    2013-01-01

    Circular Statistics in R provides the most comprehensive guide to the analysis of circular data in over a decade. Circular data arise in many scientific contexts whether it be angular directions such as: observed compass directions of departure of radio-collared migratory birds from a release point; bond angles measured in different molecules; wind directions at different times of year at a wind farm; direction of stress-fractures in concretebridge supports; longitudes of earthquake epicentres or seasonal and daily activity patterns, for example: data on the times of day at which animals are c

  13. TC4钛合金薄壁圆管纵缝TIG焊接模拟与分析%Simulation and Analysis on Longitudinal TIG Welding of TC4 Titanium Alloy Thin-walled Circular Tube

    Institute of Scientific and Technical Information of China (English)

    杨凯; 王永军; 云海涛; 白颖; 傅莉

    2015-01-01

    针对钛合金TC4薄壁圆管TIG焊接变形问题,采用SYSWELD焊接模拟软件和双椭球体热源模型,建立了TIG焊接有限元分析模型,对钛合金TC4薄壁圆管纵缝TIG焊接过程进行了模拟仿真。通过激光三维扫描对焊接试件变形情况进行测量,并对焊后温度场以及焊接变形进行了分析。研究表明,焊接变形模拟结果与试验结果规律较吻合,验证了有限元模型的有效性。%Aimed at deformation problem of TC4 titanium alloy thin-wall pipe TIG welding, it adopted welding simulation software SYSWELD and double ellipsoid heat source model to establish a finite element model to simulate TIG welding course of TC4 thin-walled tube. Through three-dimensional laser scanning measure for welded specimen deformation, the temperature field after welding and welding deformation were analyzed. The results indicated that the welding deformation simulation result is consistent with test result;the validity of finite element model was verified.

  14. CIRCULAR RIBBON FLARES AND HOMOLOGOUS JETS

    International Nuclear Information System (INIS)

    Solar flare emissions in the chromosphere often appear as elongated ribbons on both sides of the magnetic polarity inversion line (PIL), which has been regarded as evidence of a typical configuration of magnetic reconnection. However, flares having a circular ribbon have rarely been reported, although it is expected in the fan-spine magnetic topology involving reconnection at a three-dimensional (3D) coronal null point. We present five circular ribbon flares with associated surges, using high-resolution and high-cadence Hα blue wing observations obtained from the recently digitized films of Big Bear Solar Observatory. In all the events, a central parasitic magnetic field is encompassed by the opposite polarity, forming a circular PIL traced by filament material. Consequently, a flare kernel at the center is surrounded by a circular flare ribbon. The four homologous jet-related flares on 1991 March 17 and 18 are of particular interest, as (1) the circular ribbons brighten sequentially, with cospatial surges, rather than simultaneously, (2) the central flare kernels show an intriguing 'round-trip' motion and become elongated, and (3) remote brightenings occur at a region with the same magnetic polarity as the central parasitic field and are co-temporal with a separate phase of flare emissions. In another flare on 1991 February 25, the circular flare emission and surge activity occur successively, and the event could be associated with magnetic flux cancellation across the circular PIL. We discuss the implications of these observations combining circular flare ribbons, homologous jets, and remote brightenings for understanding the dynamics of 3D magnetic restructuring.

  15. 超临界压力下碳氢燃料在竖直圆管内换热特性%Heat transfer characteristics of hydrocarbon fuel at supercritical pressure in vertical circular tubes

    Institute of Scientific and Technical Information of China (English)

    张斌; 张春本; 邓宏武; 徐国强; 朱锟

    2012-01-01

    以国产航空煤油RP-3为对象研究了超临界压力下热流密度和进口温度对碳氢燃料在竖直向上管和竖直向下管的换热特性的影响.实验中热流密度变化范围为300-600kW/m。,进口温度变化范围为293-723K,压力及流量分别保持为5MPa以及3g/s.研究表明:在所有实验工况下,实验进口处将首先出现换热恶化现象,之后随着热边界层的充分发展换热逐渐增强;当管内流体状态从超临界压力液态过渡到超临界状态,由于物性的显著变化将导致换热沿管程方向得到显著强化.当进口油温超过其拟临界温度后,由于碳氢燃料吸热能力迅速降低导致管内出现了换热恶化.对于竖直向上流与竖直向下流,即使浮升力判断因子的值小于10^-5,浮升力的影响仍然不能忽略.最后,在实验结果基础上,提出了超临界压力碳氢燃料在微细管内流动的强迫对流换热经验关系式.%Experimental results of convection heat transfer to supercritical hydrocarbon fuel (RP-3) in heated vertical tubes were reported in this paper. The effects of heat flux, inlet temperature and flow direction (upward and downward) on heat transfer were studied. In the experiments, the pressure and mass flow rate were maintained at 5 MPa and 3 g/s the respectively~ the heat flux changed from 300kW/m2 to 600kW/m2 and the inlet temperature ranged from 293 K to 673 K. Test results indicate that heat transfer deterioration appears firstly at the inlet of the heated test section and then increases after thermal boundary layer is developed totally. In addition, heat transfer is enhanced near the critical point of the fuel due to the significant changes of thermalphysics properties~ when the inlet tempei'ature of RP-3 exceeds its pseudo-critical temperature, heat transfer deterioration occurs again due to the heat capacity of RP-3 decreases rapidly, Furthermore, the heat transfer

  16. Fields in multilayer beam tubes

    International Nuclear Information System (INIS)

    Equations are presented for calculating the fields from a bunched beam that penetrate into the layers of a beam tube of circular cross section. Starting from the radial wave impedance of an outer surface, the wave functions in inner layers are calculated numerically to obtain field strengths or the longitudinal beam impedance. Examples of a vertex-detector region and of an injection kicker are given

  17. Research on Axial Performances of 3D Braided Composite Circular Tubes%三维编织复合材料圆管轴向力学性能试验研究

    Institute of Scientific and Technical Information of China (English)

    黄雨霓; 刘振国

    2014-01-01

    本文针对三维四向、五向编织T700/环氧树脂复合材料,采用四步法编织工艺,编织圆管预成型件,利用VARTM工艺固化成型,并进行拉伸和压缩试验,得到两类材料圆管的轴向性能数据。试验结果表明院三维四向和五向复合材料圆管轴向性能在破坏前基本保持线弹性,四向材料拉伸和压缩模量相近,五向材料压缩模量大于拉伸模量,两者拉伸强度均远大于压缩强度,且五向材料破坏具有脆性特征。此外,三维四向编织复合材料的轴向力学性能低于三维五向编织复合材料。%Tube performs for the 3D 4-directional and 3D 5-directional materials were produced by four step braiding method and T-700/epoxy composites were made by VARTM. A study of tensile and compression properties for the two materials were carried out. The results indicate that the axial performances maintain linear elasticity before failure and the tensile strength is much larger than the compressive strength for the two materials. The tensile elastic modulus of the 3D 4-directional material is similar to the compressive elastic modulus. The compressive elastic modulus is larger than the tensile strength for the 3D 5-directional material and the failure?form is characterized by brittle cracks. Moreover, the axial properties of 3D 4-directional braided composites are lower than that of 3D 5-directional braided composites.

  18. Research on mechanical properties of slender columns made of circular steel tubes filled with steel-reinforced high-strength concrete%钢骨-圆钢管高强混凝土长柱的力学性能研究

    Institute of Scientific and Technical Information of China (English)

    陈兰响; 关萍; 刘晴晴

    2015-01-01

    To study the mechanical properties of slender columns made of circular steel tubes filled with steel-reinforced concrete ( STSRHC) , a mechanical model of the composite columns is estab-lished by the finite element software ABAQUS for the influence of the sender ratio, material strength and thickness of steel tube on the slender columns, etc. In addition, the formula of the ultimate bearing capacity of the slender columns is also established. The results indicate that the mechanical model established in ABAQUS meets the requirements. The slender ratio, eccentricity and thickness of steel tube have greater influence on the mechanical properties, and the influence of material strength and shape of built-in steel is relatively small;the bearing capacity calculated by the simpli-fied formula is in good agreement with the experimental results ( The mean value is 1. 039 , and the deviation is 0. 049), and the formula has a wide range of application.%为了研究钢骨—圆钢管高强混凝土长柱的力学性能,利用ABAQUS有限元分析软件建立组合柱的有限元分析模型,分析长细比、材料强度和钢管壁厚等因素对组合长柱力学性能的影响,并建立长柱的稳定极限承载力公式。研究结果表明:基于ABAQUS软件选取的力学模型符合要求;长细比、偏心率和钢管壁厚对组合长柱的受力性能影响较大,材料强度和型钢截面形状对其影响相对较小;建立的简化承载力公式计算结果与试验结果吻合良好(均值为1.039,偏差为0.046),适用范围广。

  19. Circular Interpolation Algorithms of 5-Axis Simultaneous CNC System

    Institute of Scientific and Technical Information of China (English)

    ZHENG Kuijing; SHANG Bo

    2006-01-01

    Spatial circular arc can be machined conveniently by a 5-axis NC machine tool. Based on the data sampling method, circular interpolation in two-dimensional plane is discussed briefly. The key is to solve the problem of circular center expressed in the workpiece coordinate system by means of the transformation matrix. Circular interpolation in three-dimensional space is analyzed in detail. The method of undetermined coefficient is used to solve the center of the spatial circle and the method of coordinate transformation is used to transform the spatial circle into the XY_plane. Circular arc in three-dimensional space can be machined by the positional 5-axis machining and the conical surface can be machined by the continuous 5-axis machining. The velocity control is presented to avoid the feedrate fluctuation. The interpolation algorithms are tested by a simulation example and the interpolation algorithms are proved feasible. The algorithms are applied to the 5-axis CNC system software.

  20. Compact waveguide circular polarizer

    Energy Technology Data Exchange (ETDEWEB)

    Tantawi, Sami G.

    2016-08-16

    A multi-port waveguide is provided having a rectangular waveguide that includes a Y-shape structure with first top arm having a first rectangular waveguide port, a second top arm with second rectangular waveguide port, and a base arm with a third rectangular waveguide port for supporting a TE.sub.10 mode and a TE.sub.20 mode, where the end of the third rectangular waveguide port includes rounded edges that are parallel to a z-axis of the waveguide, a circular waveguide having a circular waveguide port for supporting a left hand and a right hand circular polarization TE.sub.11 mode and is coupled to a base arm broad wall, and a matching feature disposed on the base arm broad wall opposite of the circular waveguide for terminating the third rectangular waveguide port, where the first rectangular waveguide port, the second rectangular waveguide port and the circular waveguide port are capable of supporting 4-modes of operation.

  1. Circular Ribbon Flares and Homologous Jets

    CERN Document Server

    Wang, Haimin

    2012-01-01

    Solar flare emissions in the chromosphere often appear as elongated ribbons on both sides of the magnetic polarity inversion line (PIL), and this has been regarded as evidence of a typical configuration of magnetic reconnection. However, flares having a closed circular ribbon have rarely been reported, although it is expected in the fan--spine magnetic topology involving reconnection at a three-dimensional (3D) coronal null point. We present five circular ribbon flares with associated surges, using high-resolution and high-cadence \\ha blue wing observations obtained from the recently digitized films of Big Bear Solar Observatory (BBSO). In all the events, a central parasitic magnetic field is encompassed by the opposite magnetic polarity, forming a circular PIL that is also traced by filament material. Consequently, a flare kernel at the center is surrounded by a circular flare ribbon. The four homologous jet-related flares on 1991 March 17 and 18 are of particular interest, as (1) the circular ribbons bright...

  2. Wiimote Experiments: Circular Motion

    Science.gov (United States)

    Kouh, Minjoon; Holz, Danielle; Kawam, Alae; Lamont, Mary

    2013-01-01

    The advent of new sensor technologies can provide new ways of exploring fundamental physics. In this paper, we show how a Wiimote, which is a handheld remote controller for the Nintendo Wii video game system with an accelerometer, can be used to study the dynamics of circular motion with a very simple setup such as an old record player or a…

  3. Gastrostomy Tube (G-Tube)

    Science.gov (United States)

    ... endoscope (a thin, flexible tube with a tiny camera and light at the tip) inserted through the ... Nemours Foundation, iStock, Getty Images, Corbis, Veer, Science Photo Library, Science Source Images, Shutterstock, and Clipart.com

  4. Ear tube insertion

    Science.gov (United States)

    Myringotomy; Tympanostomy; Ear tube surgery; Pressure equalization tubes; Ventilating tubes; Ear infection - tubes; Otitis - tubes ... trapped fluid can flow out of the middle ear. This prevents hearing loss and reduces the risk ...

  5. Analysis and simulation of vircators with step circular waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Y.; Lan, Y.C. [National Tsing Hua Univ., Hsinchu (Taiwan, Province of China). Dept. of Nuclear Engineering

    1994-12-31

    It has been previously shown that higher-power microwaves can be generated from vircators with an abrupt discontinuity in circular waveguides. In this paper the authors investigate the effects of the distance of the waveguide step from the anode on the microwave output and the dominant microwave frequency via the two-dimensional, relativistic, electromagnetic, particle-in-cell code. The parameters of the vircator in this simulation study are: a negative constant voltage of 270 kV applied to the cathode, a constant injection current of 7.3 kA at the cathode surface, 0.46 cm for the cathode to anode distance, 1.3 cm cathode radius, 12.5 cm for the drift tube length, and the radii of the front and the rear section of the drift tube are 4 and 5 cm, respectively. Simulation results show that the dominant microwave frequencies are concentrated in two bands centered roughly at 8.24 and 11 GHz. As the distance of the waveguide step from the anode increases from 0 to 7 cm, the dominant microwave frequency hops between lower- and higher-frequency bands. Among each band, the frequency gradually decreases with increasing distance of the waveguide step. They have demonstrated qualitatively, through time-domain analysis of open cavities containing no sources, the dependence of the dominant microwave frequency on the distance of the waveguide step. The output powers observed in the simulation are greatly enhanced at the waveguide steps of, roughly, 0.8, 1.7, 3.7--4.3, and 7.0 cm from the anode with respective dominant-mode excitation of TM{sub 01}, TM{sub 02}, TM{sub 03}, and TM{sub 04}.

  6. Experiments on a Crossflow Heat Exchanger With Tubes of Lenticular Shape

    OpenAIRE

    Ruth, E. K.

    1983-01-01

    Measurements of pressure losses and heat transfer rates were made for an unconventional crossflow heat exchanger with tubes of lenticular cross section so spaced to reduce variation in the velocity of the fluid outside the tubes, thus reducing separation and drag. The results of these experiments are reported for various tube spacing and demonstrate that the performance of the lenticular tube heat exchanger is superior to that of conventional circular tubes by 20 percent at ...

  7. Angle measurement error and compensation for decentration rotation of circular gratings

    Institute of Scientific and Technical Information of China (English)

    CHEN Xi-jun; WANG Zhen-huan; ZENG Qing-shuang

    2010-01-01

    As the geometric center of circular grating does not coincide with the rotation center,the angle measurement error of circular grating is analyzed.Based on the moire fringe equations in decentration condition,the mathematical model of angle measurement error is derived.It is concluded that the deeentration between the centre of circular grating and the center of revolving shaft leads to the first-harmonic error of angle measurement.The correctness of the result is proved by experimental data.The method of error compensation is presented,and the angle measurement accuracy of the circular grating is effectively improved by the error compensation.

  8. Coiled tubing

    International Nuclear Information System (INIS)

    Oil and gas wells that flow on initial completion eventually reach a condition of liquid loading that kills the wells. This results form declining reservoir pressure, decreased gas volume (velocity), increased water production and other factors that cause liquids to accumulate at the bottom of the well and exert back pressure on the formation. This restricts or in some cases prevents fluid entry into the wellbore form the formation. Flowing production can be restored or increased by reducing surface backpressure, well bore stimulation, pressure maintenance or by installing a string of smaller diameter tubing. This paper reports on installation (hanging off) of a concentric string of coiled tubing inside existing production tubing which is an economically viable, safe, convenient and effective alterative for returning some of these liquid loaded )logged-up) wells to flowing status

  9. Investigating the transitional state between circular plates and shallow spherical shells

    OpenAIRE

    Moayyad Al-Nasra; Mohamad Daoud

    2015-01-01

    The stiffness of circular plates can be increased by inducing a rise at the center of these plates; this rise converts the circular plates from two-dimensional stiffness elements into three-dimensional stiffness elements. This slight change in the geometry shifts the state of stresses from mainly bending stresses to tensilecompressive stresses. The rise at the center of a circular plate is increased gradually to the point where a shell element is formed. This paper focuses on this particul...

  10. Crushing modes of aluminium tubes under axial compression

    OpenAIRE

    Pled, Florent; Yan, Wenyi; Wen, Cui'e

    2014-01-01

    6 pages International audience A numerical study of the crushing of circular aluminium tubes with and without aluminium foam fillers has been carried out to investigate their buckling behaviours under axial compression. A crushing mode classification chart has been established for empty tubes. The influence of boundary conditions on crushing mode has also been investigated. The effect of foam filler on the crushing mode of tubes filled with foam was then examined. The predicted results ...

  11. Circularity-Measuring System

    Science.gov (United States)

    WHIPPO. WALTER B.; Rohrkaste, G. R.; Miller, John E.

    1989-01-01

    Shape gauge and associated computer constitute system measuring deviations of large cylinders from roundness. Shaped and held somewhat like crossbow, measures relative locations of three points on surface of large, round object. By making connected series of measurements around periphery technician using gauge determines deviation of object from perfect circularity. Used to measure straightness, roundness, or complicated shapes of such large geometrical objects as surfaces of aircraft and hulls of ships.

  12. Circular arc structures

    KAUST Repository

    Bo, Pengbo

    2011-07-01

    The most important guiding principle in computational methods for freeform architecture is the balance between cost efficiency on the one hand, and adherence to the design intent on the other. Key issues are the simplicity of supporting and connecting elements as well as repetition of costly parts. This paper proposes so-called circular arc structures as a means to faithfully realize freeform designs without giving up smooth appearance. In contrast to non-smooth meshes with straight edges where geometric complexity is concentrated in the nodes, we stay with smooth surfaces and rather distribute complexity in a uniform way by allowing edges in the shape of circular arcs. We are able to achieve the simplest possible shape of nodes without interfering with known panel optimization algorithms. We study remarkable special cases of circular arc structures which possess simple supporting elements or repetitive edges, we present the first global approximation method for principal patches, and we show an extension to volumetric structures for truly threedimensional designs. © 2011 ACM.

  13. Switchable circular beam deflectors

    Science.gov (United States)

    Shang, Xiaobing; Joshi, Pankaj; Tan, Jin-Yi; De Smet, Jelle; Cuypers, Dieter; Baghdasaryan, Tigran; Vervaeke, Michael; Thienpont, Hugo; De Smet, Herbert

    2016-04-01

    In this work, we report two types of electrically tunable photonic devices with circularly symmetric polarization independent beam steering performance (beam condensing resp. beam broadening). The devices consist of circular micro grating structures combined with nematic liquid crystal (LC) layers with anti-parallel alignment. A single beam deflector converts a polarized and monochromatic green laser beam (λ =543.5 nm) into a diffraction pattern, with the peak intensity appearing at the third order when 0~{{V}\\text{pp}} is applied and at the zeroth order (no deflection) for voltages above 30~{{V}\\text{pp}} . Depending on the shape of the grating structure (non-inverted or inverted), the deflection is inwards or outwards. Both grating types can be made starting from the same diamond-tooled master mold. A polarized white light beam is symmetrically condensed resp. broadened over 2° in the off state and is passed through unchanged in the on state. By stacking two such devices with mutually orthogonal LC alignment layers, polarization independent switchable circular beam deflectors are realized with a high transmittance (>80%), and with the same beam steering performance as the polarization dependent single devices.

  14. Recollision with circular polarization

    Science.gov (United States)

    Mauger, Francois; Kamor, Adam; Bandrauk, Andre; Chandre, Cristel; Uzer, Turgay

    2013-05-01

    Since its identification in the 90s, the recollision scenario has revealed to be very helpful in explaining many phenomena in atomic and molecular systems subjected to strong and short laser pulses, and it is now at the core of the strong field physics and attosecond science. For linearly polarized laser fields, the recollision scenario has been able to explain nonsequential double ionization (NSDI), high harmonic generation (HHG) and laser induced diffraction (LIED), just to cite them. The same scenario also predicts the absence of recollision when the field is circularly polarized, therefore leading to the absence of NSDI, HHG or LIED. Recently, the influence of the ellipticity of the laser has drawn an increasing level of interest in the strong field community as it is seen as a way to control the electronic dynamics and, for instance, HHG. Using classical models, the common belief of the absence of recollision with circularly polarized laser fields has been proven wrong. In my talk I will present classical and quantum evidence of the presence of recollision with circular polarization. I will discuss the conditions under which such recollisions happen and what they imply.

  15. Horizontal beam tubes in FRM-II

    International Nuclear Information System (INIS)

    The new research reactor in Garching FRM-II is equipped with 10 leak tight horizontal beam tubes (BT1 - BT10), each of them consisting of a beam tube structure taking an insert with neutron channels. The design of all beam tube structures is similar whereas the inserts are adapted to the special requirements of the using of each beam tube. Inside the reflector tank the beam tube structures are shaped by the inner cones which are made of Al-alloy with circular and rectangular cross sections. They are located in the region of maximum neutron flux (exception BT10), they are directly connected to the flanges of the reflector tank, their lengths are about 1.5 m (exception BT10) and their axes are directed tagentially to the core centre thus contributing to a low γ-noise at the experiments. (orig.)

  16. Experimental Investigation of Pulsatile Flow in Circular Tubes

    Czech Academy of Sciences Publication Activity Database

    Adamec, J.; Nožička, J.; Hanus, D.; Kořenář, Josef

    2001-01-01

    Roč. 17, č. 5 (2001), s. 1133-1136. ISSN 0748-4658 Institutional research plan: CEZ:AV0Z2060917 Keywords : pulsatile flow * laminar-turbulent transition * reynolds normal stress Subject RIV: BK - Fluid Dynamics Impact factor: 0.418, year: 2001

  17. Ear Tubes

    Science.gov (United States)

    ... of the ear drum or eustachian tube, Down Syndrome, cleft palate, and barotrauma (injury to the middle ear caused by a reduction of air pressure, ... specialist) may be warranted if you or your child has experienced repeated ... fluid in the middle ear, barotrauma, or have an anatomic abnormality that ...

  18. Inversion of the circular averages transform using the Funk transform

    International Nuclear Information System (INIS)

    The integral of a function defined on the half-plane along the semi-circles centered on the boundary of the half-plane is known as the circular averages transform. Circular averages transform arises in many tomographic image reconstruction problems. In particular, in synthetic aperture radar (SAR) when the transmitting and receiving antennas are colocated, the received signal is modeled as the integral of the ground reflectivity function of the illuminated scene over the intersection of spheres centered at the antenna location and the surface topography. When the surface topography is flat the received signal becomes the circular averages transform of the ground reflectivity function. Thus, SAR image formation requires inversion of the circular averages transform. Apart from SAR, circular averages transform also arises in thermo-acoustic tomography and sonar inverse problems. In this paper, we present a new inversion method for the circular averages transform using the Funk transform. For a function defined on the unit sphere, its Funk transform is given by the integrals of the function along the great circles. We used hyperbolic geometry to establish a diffeomorphism between the circular averages transform, hyperbolic x-ray and Funk transforms. The method is exact and numerically efficient when fast Fourier transforms over the sphere are used. We present numerical simulations to demonstrate the performance of the inversion method. Dedicated to Dennis Healy, a friend of Applied Mathematics and Engineering

  19. Simulating radiative shocks in nozzle shock tubes

    CERN Document Server

    van der Holst, B; Sokolov, I V; Daldorff, L K S; Powell, K G; Drake, R P

    2011-01-01

    We use the recently developed Center for Radiative Shock Hydrodynamics (CRASH) code to numerically simulate laser-driven radiative shock experiments. These shocks are launched by an ablated beryllium disk and are driven down xenon-filled plastic tubes. The simulations are initialized by the two-dimensional version of the Lagrangian Hyades code which is used to evaluate the laser energy deposition during the first 1.1ns. The later times are calculated with the CRASH code. This code solves for the multi-material hydrodynamics with separate electron and ion temperatures on an Eulerian block-adaptive-mesh and includes a multi-group flux-limited radiation diffusion and electron thermal heat conduction. The goal of the present paper is to demonstrate the capability to simulate radiative shocks of essentially three-dimensional experimental configurations, such as circular and elliptical nozzles. We show that the compound shock structure of the primary and wall shock is captured and verify that the shock properties a...

  20. Circularly polarized antennas

    CERN Document Server

    Gao, Steven; Zhu, Fuguo

    2013-01-01

    This book presents a comprehensive insight into the design techniques for different types of CP antenna elements and arrays In this book, the authors address a broad range of topics on circularly polarized (CP) antennas. Firstly, it introduces to the reader basic principles, design techniques and characteristics of various types of CP antennas, such as CP patch antennas, CP helix antennas, quadrifilar helix antennas (QHA), printed quadrifilar helix antennas (PQHA), spiral antenna, CP slot antennas, CP dielectric resonator antennas, loop antennas, crossed dipoles, monopoles and CP horns. Adva

  1. Antennas on circular cylinders

    DEFF Research Database (Denmark)

    Knudsen, H. L.

    1959-01-01

    antenna in a circular cylinder. By a procedure similar to the one used by Silver and Saunders, expressions have been derived for the field radiated from an arbitrary surface current distribution on a cylinder surface coaxial with a perfectly conducting cylinder. The cases where the space between the two...... cylindrical surfaces have the sane characteristic constants and different constants are treated separately. Extensive numerical computations of the field radiated from the slot antennas described here are being carried out, but no numerical results are yet available...

  2. Electron tube

    Energy Technology Data Exchange (ETDEWEB)

    Suyama, Motohiro (Hamamatsu, JP); Fukasawa, Atsuhito (Hamamatsu, JP); Arisaka, Katsushi (Los Angeles, CA); Wang, Hanguo (North Hills, CA)

    2011-12-20

    An electron tube of the present invention includes: a vacuum vessel including a face plate portion made of synthetic silica and having a surface on which a photoelectric surface is provided, a stem portion arranged facing the photoelectric surface and made of synthetic silica, and a side tube portion having one end connected to the face plate portion and the other end connected to the stem portion and made of synthetic silica; a projection portion arranged in the vacuum vessel, extending from the stem portion toward the photoelectric surface, and made of synthetic silica; and an electron detector arranged on the projection portion, for detecting electrons from the photoelectric surface, and made of silicon.

  3. Neutron tubes

    Science.gov (United States)

    Leung, Ka-Ngo; Lou, Tak Pui; Reijonen, Jani

    2008-03-11

    A neutron tube or generator is based on a RF driven plasma ion source having a quartz or other chamber surrounded by an external RF antenna. A deuterium or mixed deuterium/tritium (or even just a tritium) plasma is generated in the chamber and D or D/T (or T) ions are extracted from the plasma. A neutron generating target is positioned so that the ion beam is incident thereon and loads the target. Incident ions cause D-D or D-T (or T-T) reactions which generate neutrons. Various embodiments differ primarily in size of the chamber and position and shape of the neutron generating target. Some neutron generators are small enough for implantation in the body. The target may be at the end of a catheter-like drift tube. The target may have a tapered or conical surface to increase target surface area.

  4. Straightening tubes

    International Nuclear Information System (INIS)

    Hexagonal wrapper tubes, especially for nuclear reactor core sub-assemblies, may suffer from unacceptable bow as a result of welding wear pads to the wrapper and heat treatment. Straightening of the bow is effected by a method wherein at each of a series of axially spaced locations the faces or vertices of the tube are measured relative to a reference to determine the direction of bow at the locations. From these measurements, the appropriate axial locations for the application of corrective loading can be determined, whereby by application of the loading at a selected face or vertex for such measurements the bow is reduced. Such loading, by an actuator, can be repeated at the locations until the bow is reduced to within tolerances. (author)

  5. „So it really is a series of tubes.“ Google’s data centers, noo-politics and the architecture of hegemony in cyberspace

    Directory of Open Access Journals (Sweden)

    Thomas Pearce

    2014-01-01

    Full Text Available In recent years, the physical manifestation and infrastructure of the informational age has increasingly drawn the attention both of the popular imagination and of architectural theorists. This paper focuses on an aspect mostly overlooked to date, namely on its artistic representation. It provides a critical analysis of a series of data center photographs published by Google in October 2012 under the name “Where the internet lives”. The photographs are examined as carefully staged constructions of a specific imagination of information technology that, transcending a purely aesthetical or corporate critique, has broad political, socio-geographical and economical implications. A first analysis of their composition, digital manipulation and visual impact situates the images within a recent photographic current of the so called “anthropogenic Sublime”. The paper then zooms out to reframe the photographs as a continuation of the euphoric techno-utopian discourse that surrounded the popular dissemination of the internet in the early nineteen-nineties. This discourse hailed the internet as an inherently moral and emancipatory vehicle that, because of the non-physical nature of cyberspace, would liberate its users from traditional hegemonic dispositifs based on techniques of physical coercion. Tracing the transition from bio-political (Foucault to noo-political dispositifs (Lazarrato, Deleuze and discussing the inextricable connection between information technology, territorial conflict and socio-geographic inequality, the article goes on to account for the demise of the dream of a “bodiless and moral internet”. Finally, the data center images are re-read in more detail and discussed as part of the life-support system of a failed utopia - sustaining a popular yet reductionist understanding of the informational society and its key players.

  6. The method of radiographic testing of tube-to-tube-plate welds for nuclear power plants

    International Nuclear Information System (INIS)

    Non-destructive testing of tube-to-tube-plate welds is a complicated procedure because of small dimensions and inconvenient for control shape of the weld. Especially difficult is testing the joints without nozzle or circular groove in tube plate. The method of examination of these welds, based on the application of the isotopic source and of the compensator of the thickness of absorber is described. The specially developed cameras and equipment are also described. The attained sensitivity of testing enabled meeting the requirements obligatory for nuclear power installations. (author)

  7. Fine positioning manipulator, especially for repair PWR steam generator tubes

    International Nuclear Information System (INIS)

    The remote fine positioning manipulator has a tool support, displacement means at least in a plane parralel to the tube plate. The fine positioning means of the tool support has a camera directed to the tube plate with its axis parralel to the tubes, lighting means oriented to define by contrast the inside contour of the end of a given tube and processors for digitizing and determining the position of the center of the tube and control the movement of the tool support

  8. 77 FR 64478 - Circular Welded Carbon-Quality Steel Pipe From India: Final Determination of Sales at Less Than...

    Science.gov (United States)

    2012-10-22

    ... Preliminary Determination, 77 FR at 32562-63. \\3\\ See Circular Welded Carbon-Quality Steel Pipe From India...; Certain Welded Carbon Steel Standard Pipes and Tubes From India, 51 FR 17384 (May 12, 1986). Therefore... International Trade Administration Circular Welded Carbon-Quality Steel Pipe From India: Final Determination...

  9. 76 FR 78313 - Circular Welded Carbon-Quality Steel Pipe From India, Oman, the United Arab Emirates, and Vietnam

    Science.gov (United States)

    2011-12-16

    ... COMMISSION Circular Welded Carbon-Quality Steel Pipe From India, Oman, the United Arab Emirates, and Vietnam... United Arab Emirates, and Vietnam of circular welded carbon- quality steel pipe, provided for in... October 26, 2011, a petition was filed with the Commission and Commerce by Allied Tube and Conduit,...

  10. Pi, Archimedes and circular splines

    OpenAIRE

    Sablonnière, Paul

    2013-01-01

    In the present paper, we give approximate values of $\\pi$ deduced from the areas of inscribed and circumscribed quadratic and cubic circular splines. Similar results on circular splines of higher degrees and higher approximation orders can be obtained in the same way. We compare these values to those obtained by computing the {\\em perimeters} of those circular splines. We observe that the former are much easier to compute than the latter and give results of the same order. It also appears tha...

  11. photomultiplier tubes

    CERN Multimedia

    photomultiplier tubes. A device to convert light into an electric signal (the name is often abbreviated to PM). Photomultipliers are used in all detectors based on scintillating material (i.e. based on large numbers of fibres which produce scintillation light at the passage of a charged particle). A photomultiplier consists of 3 main parts: firstly, a photocathode where photons are converted into electrons by the photoelectric effect; secondly, a multiplier chain consisting of a serie of dynodes which multiply the number of electron; finally, an anode, which collects the resulting current.

  12. photomultiplier tube

    CERN Multimedia

    photomultiplier tubes. A device to convert light into an electric signal (the name is often abbreviated to PM). Photomultipliers are used in all detectors based on scintillating material (i.e. based on large numbers of fibres which produce scintillation light at the passage of a charged particle). A photomultiplier consists of 3 main parts: firstly, a photocathode where photons are converted into electrons by the photoelectric effect; secondly, a multiplier chain consisting of a serie of dynodes which multiply the number of electron; finally, an anode, which collects the resulting current.

  13. Oscillatory flow in bifurcating tubes

    International Nuclear Information System (INIS)

    Respiratory fluid mechanics is characterized by flow through bifurcating, Y-shaped, tubes. Steady flow through such geometries has been studied in detail by several authors. However, the recent widespread use of high frequency mechanical assistance of ventilation has generated interest in unsteady flows. A symmetric, singly branching pipe has been constructed, with its bifurcation shaped to model pulmonary conditions. The form of the bifurcation is based on CAT scans of human tracheal carinas. Its features include an area change of the parent tube from circular to roughly elliptical near the junction, a pinch-off effect on the parent tube, smoothly curved outer walls at the junction, and a sharp flow divider. Parent and daughter tubes have an l/d ratio of > 50, so that entrance effects are avoided. In order to better understand the effects of unsteadiness, piston driven, laminar, purely oscillatory flow has been established in the pipe for a variety of Womersley numbers. By appropriate choices of flow frequency and amplitude, fluid viscosity, and pipe diameter, tracheal Reynolds and Womersley numbers have been matched for resting breathing (tidal volume of 600 ml to 0.25 Hz), high frequency breathing (50 ml at 5 Hz), and intermediate breathing levels

  14. Circular PVDF Airborne Transducer

    Institute of Scientific and Technical Information of China (English)

    JIAO Li-hua; XU Li-mei; HONG Hu

    2007-01-01

    With the required increased audio pressure of the parametric ultrasonic transducer array and the difficulty to theoretically analyse the complex ultrasonic structure in audio beam application, an computafionally efficient model is desired to describe the characteristic of the parametric ultrasonic transducer array for the system design and optimization. By applying the symmetry boundary conditions at the mid-plane in the thickness direction, a finite element model based on the half thickness simplification is presented to analyze the parametric circular transducer which is designed by gluing the poly Vinylidene fluoride film (PVDF). The validity of the proposed model is confirmed by a comparison of finite element aalysis results with the theoretical value and experimental data, which show that they are making a good agreement with each other.

  15. Operational circular No. 1 (Rev. 1) – Operational circulars

    CERN Multimedia

    HR Department

    2011-01-01

    Operational Circular No. 1 (Rev. 1) is applicable to members of the personnel and other persons concerned. Operational Circular No. 1 (Rev. 1) entitled "Operational circulars", approved following discussion at the Standing Concertation Committee meeting on 4 May 2011, is available on the intranet site of the Human Resources Department: https://hr-docs.web.cern.ch/hr-docs/opcirc/opcirc.asp It cancels and replaces Operational Circular No. 1 entitled "Operational Circulars” of December 1996. This new version clarifies, in particular, that operational circulars do not necessarily arise from the Staff Rules and Regulations, and the functional titles have been updated to bring them into line with the current CERN organigram. Department Head Office  

  16. Comparative Study and Analysis between Helical Coil and Straight Tube Heat Exchanger

    OpenAIRE

    N. D. Shirgire; Amit Thakur

    2014-01-01

    The purpose of this study is to determine the relative advantage of using a helically coiled heat exchanger against a straight tube heat exchanger. It is found that the heat transfer in helical circular tubes is higher as compared to Straight tube due to their shape. Helical coils offer advantageous over straight tubes due to their compactness and increased heat transfer coefficient. The increased heat transfer coefficients are a consequence of the curvature of the coil, which...

  17. Advanced Illness: Feeding Tubes and Ventilators

    Science.gov (United States)

    ... Address, Jewish Lights Publishing, 2000. www.jewishlights.com Bioethics , Thomas Shannon, ed. Paulist Press, 2009 Swallowing Problems , ... 2004 The Feeding Tube Dilemma, The Center for Bioethics and Human Dignity, 1/27/06, cbhd.org ...

  18. Implementing circularity using partial evaluation

    DEFF Research Database (Denmark)

    Lawall, Julia Laetitia

    2001-01-01

    Complex data dependencies can often be expressed concisely by defining a variable in terms of part of its own value. Such a circular reference can be naturally expressed in a lazy functional language or in an attribute grammar. In this paper, we consider circular references in the context of an...

  19. Circular chemiresistors for microchemical sensors

    Science.gov (United States)

    Ho, Clifford K.

    2007-03-13

    A circular chemiresistor for use in microchemical sensors. A pair of electrodes is fabricated on an electrically insulating substrate. The pattern of electrodes is arranged in a circle-filling geometry, such as a concentric, dual-track spiral design, or a circular interdigitated design. A drop of a chemically sensitive polymer (i.e., chemiresistive ink) is deposited on the insulating substrate on the electrodes, which spreads out into a thin, circular disk contacting the pair of electrodes. This circularly-shaped electrode geometry maximizes the contact area between the pair of electrodes and the polymer deposit, which provides a lower and more stable baseline resistance than with linear-trace designs. The circularly-shaped electrode pattern also serves to minimize batch-to-batch variations in the baseline resistance due to non-uniform distributions of conductive particles in the chemiresistive polymer film.

  20. 76 FR 76369 - Circular Welded Non-Alloy Steel Pipe From the Republic of Korea: Preliminary Results of the...

    Science.gov (United States)

    2011-12-07

    ... Less Than Fair Value: Certain Circular Welded Non-Alloy Steel Pipe from Korea, 57 FR 49453 (November 2...: Light- Walled Rectangular Pipe and Tube From Mexico, 73 FR 5515, 5522 (January 30, 2008) (``LWR Pipe... Rectangular Pipe and Tube from Mexico, 73 FR 35649 (June 24, 2008). In particular, we analyze...

  1. 77 FR 32562 - Circular Welded Carbon-Quality Steel Pipe From India: Preliminary Determination of Sales at Less...

    Science.gov (United States)

    2012-06-01

    ... FR at 72164-5. On December 9, 2011, we received comments from a UAE producer named Universal Tube and...: Circular Welded Carbon Quality Steel Pipe from the People's Republic of China, 73 FR 31970 (June 5, 2008... Duty Order; Certain Welded Carbon Steel Standard Pipes and Tubes from India, 51 FR 17384 (May 12,...

  2. Future Circular Colliders

    CERN Document Server

    AUTHOR|(CDS)2108454; Zimmermann, Frank

    2015-01-01

    In response to a request from the 2013 Update of the European Strategy for Particle Physics, the global Future Circular Collider (FCC) study is preparing the foundation for a next-generation large-scale accelerator infrastructure in the heart of Europe. The FCC study focuses on the design of a 100-TeV hadron collider (FCC-hh), to be accommodated in a new ∼100 km tunnel near Geneva. It also includes the design of a high-luminosity electron-positron collider (FCC-ee), which could be installed in the same tunnel as a potential intermediate step, and a lepton-hadron collider option (FCC-he). The scope of the FCC study comprises accelerators, technology, infrastructure, detectors, physics, concepts for worldwide data services, international governance models, and implementation scenarios. Among the FCC core technologies figure 16-T dipole magnets, based on Nb3Sn superconductor, for the FCC-hh hadron collider, and a highly efficient superconducting radiofrequency system for the FCC-ee lepton collider. The interna...

  3. Future Circular Colliders

    CERN Document Server

    AUTHOR|(CDS)2108454; Zimmermann, Frank

    2015-01-01

    In response to a request from the 2013 Update of the European Strategy for Particle Physics, the global Future Circular Collider (FCC) study is preparing the foundation for a next-generation large-scale accelerator infrastructure in the heart of Europe. The FCC study focuses on the design of a 100-TeV hadron collider (FCC-hh), to be accommodated in a new ∼100 km tunnel near Geneva. It also includes the design of a high-luminosity electron-positron collider (FCC-ee), which could be installed in the same tunnel as a potential intermediate step, and a lepton-hadron collider option (FCC-he). The scope of the FCC study comprises accelerators, technology, infrastructure, detector, physics, concepts for worldwide data services, international governance models, and implementation scenarios. Among the FCC core technologies figure 16-T dipole magnets, based on Nb3Sn superconductor, for the FCC-hh hadron collider, and a highly efficient superconducting radiofrequency system for the FCC-ee lepton collider. The internat...

  4. Towards Future Circular Colliders

    CERN Document Server

    AUTHOR|(CDS)2108454; Zimmermann, Frank

    2015-01-01

    The Large Hadron Collider (LHC) at CERN presently provides proton-proton collisions at a centre-of-mass (c.m.) energy of 13 TeV. The LHC design was started more than 30 years ago, and its physics programme will extend through the second half of the 2030’s. The global Future Circular Collider (FCC) study is now preparing for a post-LHC project. The FCC study focuses on the design of a 100-TeV hadron collider (FCC-hh) in a new ∼100 km tunnel. It also includes the design of a high-luminosity electron-positron collider (FCC-ee) as a potential intermediate step, and a lepton-hadron collider option (FCC-he). The scope of the FCC study comprises accelerators, technology, infrastructure, detectors, physics, concepts for worldwide data services, international governance models, and implementation scenarios. Among the FCC core technologies figure 16-T dipole magnets, based on $Nb_3Sn$ superconductor, for the FCC-hh hadron collider, and a highly efficient superconducting radiofrequency system for the FCC-ee lepton c...

  5. Tracheostomy tube - eating

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000464.htm Tracheostomy tube - eating To use the sharing features on ... when you swallow foods or liquids. Eating and Tracheostomy Tubes When you get your tracheostomy tube, or ...

  6. Precision alignment of permanent magnet drift tubes

    International Nuclear Information System (INIS)

    The Lawrence Berkeley National Laboratory (LBNL) technique of drift-tube alignment has been resurrected at Los Alamos for the precision alignment of 1-cm-core drift tubes that carry high gradient rare-earth-cobalt quadrupoles. Because the quadrupoles cannot be switched off, this technique is not applicable to a drift-tube assembly, but tests indicate that individual magnetic centers can be detected with a precision of +/-0.003 mm. Methods of transferring this information to machined alignment flats on the sides of the drift-tube body are discussed. With measurements of drift tubes designed for a 100-mA, 425-MHz drift-tube linac, offsets between the geometric and magnetic axes of up to +/-0.05 mm were detected following final assembly and welding. This degree of offset is serious if not accommodated, because it represents the entire alignment tolerance for the 40-cell tank. The measurement equipment and technique are described

  7. Investigation of electron paramagnetic resonance in carbon tubes

    Science.gov (United States)

    Byszewski, P.; Nabialek, A.

    1996-04-01

    Electron paramagnetic resonance (EPR) on carbon nanotubes was measured in a wide range of temperatures, the resonance disappeared after oxidizing the tubes. The results are discussed in terms of graphite properties and a model introducing a deformation potential to describe tubular structure. It leads to persistent ring currents in the magnetic field due to the carriers circular motion around a tube. A spin angular-momentum interaction is discussed in an attempt to explain the lack of EPR in purified carbon nanotubes.

  8. Large drift tube arrays with external delay line readout

    International Nuclear Information System (INIS)

    The construction and performance of 2 meter long, 5 cm diameter, circular drift tubes made of 1 mm thick bakelite paper coated inside with conductive paint. The longitudinal coordinate is read-out with an external delay line system. The measured spatial resolution obtained from the drift time is close to 180 μm (one standard deviation). A system of 1100 tubes has been built for a muon experiment

  9. Carbon Monoxide Information Center

    Medline Plus

    Full Text Available ... Consumers Businesses Contact CPSC Website Design Feedback Consumers: Español Businesses: Español , 中文 , Tiếng Việt Connect with Us : Twitter YouTube ... Safely Home / Safety Education / Safety Education Centers En Español Carbon Monoxide Information Center The Invisible Killer Carbon ...

  10. Circularly-Polarized Microstrip Antenna

    Science.gov (United States)

    Stanton, P. H.

    1985-01-01

    Microstrip construction compact for mobile applications. Circularly polarized microstrip antenna made of concentric cylindrical layers of conductive and dielectric materials. Coaxial cable feedlines connected to horizontal and vertical subelements from inside. Vertical subelement acts as ground for horizontal subelement.

  11. Titanium condenser tubes

    International Nuclear Information System (INIS)

    The corrosion resistance of titanium in sea water is extremely excellent, but titanium tubes are expensive, and the copper alloy tubes resistant in polluted sea water were developed, therefore they were not used practically. In 1970, ammonia attack was found on the copper alloy tubes in the air-cooled portion of condensers, and titanium tubes have been used as the countermeasure. As the result of the use, the galvanic attack an copper alloy tube plates with titanium tubes as cathode and the hydrogen absorption at titanium tube ends owing to excess electrolytic protection were observed, but the corrosion resistance of titanium tubes was perfect. These problems can be controlled by the application of proper electrolytic protection. The condensers with all titanium tubes adopted recently in USA are intended to realize perfectly no-leak condensers as the countermeasure to the corrosion in steam generators of PWR plants. Regarding large condensers of nowadays, three problems are pointed out, namely the vibration of condenser tubes, the method of joining tubes and tube plates, and the tubes of no coolant leak. These three problems in case of titanium tubes were studied, and the problem of the fouling of tubes was also examined. The intervals of supporting plates for titanium tubes should be narrowed. The joining of titanium tubes and titanium tube plates by welding is feasible and promising. The cleaning with sponge balls is effective to control fouling. (Kako, I.)

  12. Circumferential buckling instability of a growing cylindrical tube

    KAUST Repository

    Moulton, D.E.

    2011-03-01

    A cylindrical elastic tube under uniform radial external pressure will buckle circumferentially to a non-circular cross-section at a critical pressure. The buckling represents an instability of the inner or outer edge of the tube. This is a common phenomenon in biological tissues, where it is referred to as mucosal folding. Here, we investigate this buckling instability in a growing elastic tube. A change in thickness due to growth can have a dramatic impact on circumferential buckling, both in the critical pressure and the buckling pattern. We consider both single- and bi-layer tubes and multiple boundary conditions. We highlight the competition between geometric effects, i.e. the change in tube dimensions, and mechanical effects, i.e. the effect of residual stress, due to differential growth. This competition can lead to non-intuitive results, such as a tube growing to be thinner and yet buckle at a higher pressure. © 2011 Elsevier Ltd. All rights reserved.

  13. Coloring fuzzy circular interval graphs

    OpenAIRE

    Eisenbrand, Friedrich; Niemeier, Martin

    2012-01-01

    Computing the weighted coloring number of graphs is a classical topic in combinatorics and graph theory. Recently these problems have again attracted a lot of attention for the class of quasi-line graphs and more specifically fuzzy circular interval graphs. The problem is NP-complete for quasi-line graphs. For the subclass of fuzzy circular interval graphs however, one can compute the weighted coloring number in polynomial time using recent results of Chudnovsky and Ovetsky and of King and Re...

  14. Analytical modeling of capillary flow in tubes of nonuniform cross section.

    Science.gov (United States)

    Liou, William W; Peng, Yongqing; Parker, Peter E

    2009-05-01

    The interface rise for the flow in a capillary with a nonuniform cross section distribution along a straight center axis is investigated analytically in this paper. Starting from the Navier-Stokes equations, we derive a model equation for the time-dependent rise of the capillary interface by using an approximated three-dimensional flow velocity profiles. The derived nonlinear, second-order differential equation can be solved numerically using the Runge-Kutta method. The nonuniformity effect is included in the inertial and viscous terms of the proposed model. The present model is validated by comparing the solutions for a circular cylindrical tube, rectangular cylindrical microchannels, and convergent-divergent and divergent-convergent capillaries. The validated model has been applied to capillaries with parabolic varying wall, sinusoidal wall, and divergent sinusoidal wall. The inertial and viscous effects on the dynamic capillary rise and the equilibrium height are investigated in detail. PMID:19232635

  15. Circularly polarized open-loop antenna

    OpenAIRE

    Li, Rong-Lin; Fusco, Vincent F.; Nakano, Hisamatsu

    2003-01-01

    A printed circular open-loop antenna is introduced as a simple structure for producing circular polarization; the antenna is fed with a coaxial probe. By introducing a gap within the circular loop a traveling-wave current is excited and thus circularly polarized radiation can be achieved. An optimized circularly polarized antenna is designed through numerical analysis using a so-called parametric method of moment technique. Experimental verification of the new antenna is presented. The antenn...

  16. Claw-free circular-perfect graphs

    OpenAIRE

    Pecher, Arnaud; Zhu, Xuding

    2007-01-01

    The circular chromatic number of a graph is a well studied refinement of the chromatic number. Circular perfect graphs is a superclass of perfect graphs defined by means of this more general coloring concept. This paper studies claw free circular perfect graphs. A consequence of the strong perfect graph theorem is that minimal circular perfect graphs G. In contrast to this result, it is shown in that minimal circular imperfect graphs G can have arbitrarily large independence number and arbitr...

  17. Transfer coefficients for plate fin and elliptical tube heat exchangers

    International Nuclear Information System (INIS)

    In order to determine transfer coefficients for plate fin and elliptical tube exchangers, mass transfer experiments have been performed using the naphthalene sublimation technique. By means of the heat-mass transfer analogy, the results can be converted to heat transfer results. The transfer coefficients were compared with those for circular tube exchangers and the comparison revealed no major differences. This is a positive outcome, since the use of elliptical tubes may reduce substantially the pressure drop, without affecting the transfer characteristics.(Author)

  18. Energy harvesting with piezoelectric circular membrane under pressure loading

    International Nuclear Information System (INIS)

    This paper presents a comprehensive theoretical model for predicting the energy generating performance of an energy harvesting device that uses a piezoelectric circular membrane subject to pressure fluctuation. PVDF (polyvinylidene fluoride) film is adopted for the membrane. In order to predict the power generating performance due to stretching and bending of the membrane, the total stress on the membrane, rather than the stress at the center point of the circular membrane, is determined using the energy method. Analytical results indicate that the theoretically predicted generated power of the device under normal blood pressure variation is close to experimental results available in the literature. This comprehensive model provides a useful design tool during parameter optimization for energy harvesters that use piezoelectric circular membranes for a pressure fluctuating system. (paper)

  19. Heat Transfer Studies in Tube Banks with Integral Wake Splitters

    Directory of Open Access Journals (Sweden)

    Suzairin Md Seri

    2009-09-01

    Full Text Available This paper reports the findings from heat transfer studies with the presence of extended surfaces from tube banks which are termed as integral wake splitter plates. Employing this type of fins, investigations on heat transfer characteristics on a single circular tube as well as tube banks were carried out in cross flow of air in a rectangular duct. Experiments were carried out in the Reynolds number range 5 x 103 to 105 on a single cylinder of various splitter length-to-tube diameter ratios, L/D = 0.5, 1.0, 1.5 and 2.0. Further, tube banks consisting of 12 rows and 3 tubes per row in equilateral triangle arrangements with transverse pitch to diameter ratio, a = 2, were also investigated, the banks being made up of plain tubes or tubes with splitters. Heat transfer characteristics were studied for tubes with L/D = 0, 0.5 and 1.0 under constant heat flux conditions. Tube banks with L/D = 1.0 yielded the highest heat transfer rates. Findings from this work may be adopted to be utilized in various industrial applications such as economizer of a steam boiler, air-conditioning coils or waste heat recovery systems.

  20. High Performance Circularly Polarized Microstrip Antenna

    Science.gov (United States)

    Bondyopadhyay, Probir K. (Inventor)

    1997-01-01

    A microstrip antenna for radiating circularly polarized electromagnetic waves comprising a cluster array of at least four microstrip radiator elements, each of which is provided with dual orthogonal coplanar feeds in phase quadrature relation achieved by connection to an asymmetric T-junction power divider impedance notched at resonance. The dual fed circularly polarized reference element is positioned with its axis at a 45 deg angle with respect to the unit cell axis. The other three dual fed elements in the unit cell are positioned and fed with a coplanar feed structure with sequential rotation and phasing to enhance the axial ratio and impedance matching performance over a wide bandwidth. The centers of the radiator elements are disposed at the corners of a square with each side of a length d in the range of 0.7 to 0.9 times the free space wavelength of the antenna radiation and the radiator elements reside in a square unit cell area of sides equal to 2d and thereby permit the array to be used as a phased array antenna for electronic scanning and is realizable in a high temperature superconducting thin film material for high efficiency.

  1. Podokinetic circular vection: characteristics and interaction with optokinetic circular vection.

    Science.gov (United States)

    Becker, W; Kliegl, K; Kassubek, J; Jürgens, R

    2016-07-01

    Stabilising horizontal body orientation in space without sight on a rotating platform by holding to a stationary structure and circular 'treadmill' stepping in the opposite direction can elicit an illusion of self-turning in space (Bles and Kapteyn in Agressologie 18:325-328, 1977). Because this illusion is analogous to the well-known illusion of optokinetic circular vection (oCV), we call it 'podokinetic circular vection' (pCV) here. Previous studies using eccentric stepping on a path tangential to the rotation found that pCV was always contraversive relative to platform rotation. In contrast, when our subjects stepped at the centre of rotation about their vertical axis, we observed an inverted, ipsiversive pCV as a reproducible trait in many of our subjects. This ipCV occurred at the same latency as the pCV of subjects reporting the actually expected contraversive direction, but had lower gain. In contrast to pCV, the nystagmus accompanying circular treadmill stepping had the same direction in all individuals (slow phase in the direction of platform motion). The direction of an individual's pCV predicted the characteristics of the CV resulting from combined opto- and podokinetic stimulation (circular treadmill stepping while viewing a pattern rotating together with the platform): in individuals with contraversive pCV, latency shortened and both gain and felt naturalness increased in comparison with pure oCV, whereas the opposite (longer latency, reduced gain and naturalness) occurred in individuals with ipCV. Taken together, the reproducibility of ipCV, the constant direction of nystagmus and the fact that pCV direction predicts the outcome of combined stimulation suggest that ipCV is an individual trait of many subjects during compensatory stepping at the centre of rotation. A hypothetical model is presented of how ipCV possibly could arise. PMID:26965438

  2. Low-Reynolds number swimming in a capillary tube

    CERN Document Server

    Zhu, Lailai; Brandt, Luca

    2013-01-01

    We use the boundary element method to study the low-Reynolds number locomotion of a spherical model microorganism in a circular tube. The swimmer propels itself by tangen- tial or normal surface motion in a tube whose radius is on the order of the swimmer size. Hydrodynamic interactions with the tube walls significantly affect the average swimming speed and power consumption of the model microorganism. In the case of swimming parallel to the tube axis, the locomotion speed is always reduced (resp. increased) for swimmers with tangential (resp. normal) deformation. In all cases, the rate of work nec- essary for swimming is increased by confinement. Swimmers with no force-dipoles in the far field generally follow helical trajectories, solely induced by hydrodynamic interactions with the tube walls, and in qualitative agreement with recent experimental observations for Paramecium. Swimmers of the puller type always display stable locomotion at a lo- cation which depends on the strength of their force dipoles: sw...

  3. Critical heat flux in tubes and tight hexagonal rod lattices

    International Nuclear Information System (INIS)

    The critical heat flux (CHF) in small-diameter tubes and in tight hexagonal 7-rod and 37-rod bundles was investigated in the KRISTA test facility, using Freon 12 as the working fluid. The measurements in tubes showed that the influence of the tube diameter on CHF cannot be described as suggested by earlier publications with sufficient accuracy. CHF in bundles is lower than in tubes under comparable conditions. The influence of spacers (grid spacers, wire wraps) on CHF was found to be governed by local steam qualities. A comparison of the test results with some CHF prediction methods showed that the look-up table method reproduces the test results in circular tubes most accurately. Combined with CHF look-up tables, subchannel analysis and Ahmad's fluid-to-fluid scaling law, Freon experiments have proven to be a suitable tool for CHF prediction in water-cooled rod bundles. (orig.)

  4. 3D measurement using circular gratings

    Science.gov (United States)

    Harding, Kevin

    2013-09-01

    3D measurement using methods of structured light are well known in the industry. Most such systems use some variation of straight lines, either as simple lines or with some form of encoding. This geometry assumes the lines will be projected from one side and viewed from another to generate the profile information. But what about applications where a wide triangulation angle may not be practical, particularly at longer standoff distances. This paper explores the use of circular grating patterns projected from a center point to achieve 3D information. Originally suggested by John Caulfield around 1990, the method had some interesting potential, particularly if combined with alternate means of measurement from traditional triangulation including depth from focus methods. The possible advantages of a central reference point in the projected pattern may offer some different capabilities not as easily attained with a linear grating pattern. This paper will explore the pros and cons of the method and present some examples of possible applications.

  5. TRIPLET CIRCULAR HOUGH TRANSFORM FOR CIRCLE DETECTION

    Institute of Scientific and Technical Information of China (English)

    Luo Daisheng; He Xiaohai; Teng Qizhi; Tao Qingchuan

    2002-01-01

    A new method, triplet circular Hough transform, is proposed for circle detection in image processing and pattern recognition. In the method, a curve in an image is first detected.Next, a sequence of three points on the curve are selected, a sequence of parameters (a,b,r)corresponding to the three points are calculated by solving the circle equation of the curve, and two 2-D accumulators A(a,b) and R(a,b) are accumulated with 1 and r, respectively. Then the parameters {(a, b, r)} of the circles fitting the curve are determined from A(a, b) and R(a, b) by searching for the local maximum over A(a,b). Because no computation loops over center (a, b)and/or radius r are needed, the method is faster than the basic and directional gradient methods.It needs also much smaller memory for accumulation.

  6. Circular RNA expands its territory.

    Science.gov (United States)

    Bao, Chunyang; Lyu, Dongbin; Huang, Shenglin

    2016-03-01

    Circular RNAs (circRNAs) represent a novel class of widespread non-coding RNAs in eukaryotes. They are unusually stable RNA molecules with cell type-specific expression patterns, and are predominantly present in the cytoplasm. We recently demonstrated the existence of abundant circRNAs in exosomes and suggest a potential application of exosomal circRNAs for cancer detection. PMID:27308606

  7. High intensity circular proton accelerators

    International Nuclear Information System (INIS)

    Circular machines suitable for the acceleration of high intensity proton beams include cyclotrons, FFAG accelerators, and strong-focusing synchrotrons. This paper discusses considerations affecting the design of such machines for high intensity, especially space charge effects and the role of beam brightness in multistage accelerators. Current plans for building a new generation of high intensity 'kaon factories' are reviewed. 47 refs

  8. Circular polarization observed in bioluminescence

    NARCIS (Netherlands)

    Wijnberg, Hans; Meijer, E.W.; Hummelen, J.C.; Dekkers, H.P.J.M.; Schippers, P.H.; Carlson, A.D.

    1980-01-01

    While investigating circular polarization in luminescence, and having found it in chemiluminescence, we have studied bioluminescence because it is such a widespread and dramatic natural phenomenon. We report here that left and right lanterns of live larvae of the fireflies, Photuris lucicrescens and

  9. Application of circular filter inserts

    International Nuclear Information System (INIS)

    High efficiency particulate air (HEPA) filters are used in the ventilation of nuclear plant as passive clean-up devices. Traditionally, the work-horse of the industry has been the rectangular HEPA filter. An assessment of the problems associated with remote handling, changing, and disposal of these rectangular filters suggested that significant advantages to filtration systems could be obtained by the adoption of HEPA filters with circular geometry for both new and existing ventilation plants. This paper covers the development of circular geometry filters and highlights the advantages of this design over their rectangular counterparts. The work has resulted in a range of commercially available filters for flows from 45 m3/h up to 3400 m3/h. This paper also covers the development of a range of sizes and types of housings that employ simple change techniques which take advantage of the circular geometry. The systems considered here have been designed in response to the requirements for shielded (remote filter change) and for unshielded facilities (potentially for bag changing of filters). Additionally the designs have allowed for the possibility of retrofitting circular geometry HEPA filters in place of the rectangular geometry filter

  10. Giant polygons and circular graben in western Utopia basin, Mars: Exploring possible formation mechanisms

    Science.gov (United States)

    Buczkowski, Debra L.; Seelos, Kim D.; Cooke, Michele L.

    2012-08-01

    Large-scale fracture systems surrounding the Utopia basin include giant polygons and circular graben. Data covering the northern Utopia basin now allow high-resolution mapping of these features in all regions of the basin. Giant polygons to the north and south of the basin are different in both size and morphology, leading to the polygon classifications (1) S-style, (2) subdued S-style, (3) northern S-style and (4) N-style. Also, ten circular graben have been identified to the north of the Utopia basin. These have generally larger diameters than southern circular graben, and their fracture morphology is similar to N-style giant polygons. As with southern circular graben, the surface relief of the depression inside the northern circular graben scales directly with diameter. However, northern circular graben have less steep trend slopes, larger average diameters and greater ring spacing compared to southern circular graben of the same diameter and similar distance to the center of the Utopia basin. Both the giant polygons and circular graben of Utopia Planitia are consistent with formation by volumetric compaction of a fine-grained sedimentary material covering an uneven buried surface. Giant polygon size variations can be explained by the material being wet to the south but frozen or partially frozen to the north, while differences between northern and southern circular graben may be attributed to changes in cover thickness. Differences in fracture morphology can be explained by subsequent alteration of the northern troughs due to polar processes.

  11. Neural Tube Defects

    Science.gov (United States)

    Neural tube defects are birth defects of the brain, spine, or spinal cord. They happen in the first month ... that she is pregnant. The two most common neural tube defects are spina bifida and anencephaly. In spina bifida, ...

  12. Tracheostomy tube - speaking

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000465.htm Tracheostomy tube - speaking To use the sharing features on ... are even speaking devices that can help you. Tracheostomy Tubes and Speaking Air passing through vocal cords ( ...

  13. Gastrostomy feeding tube - bolus

    Science.gov (United States)

    ... a gastrostomy tube. Delmar’s Fundamental and Advanced Nursing Skills . 2nd Ed. Albany, NY: Delmar Thomson Learning; 2003: 742-749. Simmons, Remmington R.The percutaneous endoscopic gastrostomy tube: a nurse's guide to PEG tubes. Medsurg Nurs . 2013 Mar- ...

  14. KER-2 tube history

    Energy Technology Data Exchange (ETDEWEB)

    Banister, W.C.

    1963-08-16

    Zirconium process tube No. 1986 was installed in KE Reactor tube channel No. 2864 on April 16, 1959. This report describes the history and the conditions to which it was exposed during its residence in the reactor. The tube was removed on May 31, 1963.

  15. Substrate Integrated Waveguide Diplexer Based on Circular Triplet Combline Filters

    OpenAIRE

    Sirci, Stefano; Martínez Pérez, Jorge Daniel; Vague Cardona, José Joaquín; Boria Esbert, Vicente Enrique

    2015-01-01

    The design of substrate integrated waveguide (SIW) diplexers, based on combline triplet sections with transmission zeros (TZs) placed below and above the passband, is presented. In order to control the location of the TZs, positive and negative couplings are conveniently provided. A highly compact implementation based on circular substrate integrated coaxial resonators is proposed. An X band diplexer with channel center frequencies at 9.5 and 10.5 GHz and absolute bandwidths of 400 MHz is ...

  16. Opportunities with top quarks at future circular colliders

    CERN Document Server

    Fuks, Benjamin

    2014-01-01

    We describe various studies relevant for top physics at future circular collider projects currently under discussion. We show how highly-massive top-antitop systems produced in proton-proton collisions at a center-of-mass energy of 100 TeV could be observed and employed for constraining top dipole moments, investigate the reach of future proton-proton and electron-positron machines to top flavor-changing neutral interactions, and discuss top parton densities.

  17. Convex mappings on some circular domains

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this paper,we consider some circular domains.And we give an extension theorem for some normalized biholomorphic convex mapping on some circular domains.Especially,we discover the normalized biholomorphic convex mapping on some circular domains have the form f(z) =(f1(z1),...,fn(zn)),where fj:D → C are normalized biholomorphic convex mapping.

  18. A selected ion flow tube study of the reactions of H3O+, NO+ and O-2(+center dot) with seven isomers of hexanol in support of SIFT-MS

    Czech Academy of Sciences Publication Activity Database

    Smith, D.; Sovová, Kristýna; Španěl, Patrik

    2012-01-01

    Roč. 319, MAY 1 2012 (2012), s. 25-30. ISSN 1387-3806 R&D Projects: GA ČR GA203/09/0256 Institutional support: RVO:61388955 Keywords : selected ion flow tube mass spectrometry * proton transfer * ion molecule reaction Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.142, year: 2012

  19. 大连国际会议中心支撑筒设计与试验研究%Design and test research on the support tube in Dalian International Conference Center

    Institute of Scientific and Technical Information of China (English)

    王立长; 王国雷; 刘楠; 左清林; 曹万林; 纪大海; 曲鑫蕃

    2012-01-01

    The structure of Dalian International Conference Center consists of 14 concealed steel frame reinforced concrete transport cylinders resisting the entire building vertical load and horizontal lateral.Due to the peculiar structure of the cylinder,the force is different from the traditional structure of the high-rise building of the core barrel.In order to meet the aseismic design and connection construction of structure,the hide inside with inclined brace steel truss concrete composite cylinder was used in this project,and tectonic measures were taken according to the necessary stress characteristics.For the further study of the cylinder performance,the scale cylinder model experiment was studied on the seismic behavior combined with practical engineering,including its stiffness and deterioration process,bearing capacity,ductility,energy dissipation capacity,failure characteristics and tectonic measures effectiveness.Based on the test results,further measures were taken for the test of weak parts in the engineering in order to improve the seismic capacity of cylinder.Research shows that inside with inclined brace steel frame reinforced concrete combined cylinder has high bearing capacity.Concealed steel frame can obviously improve the cylinder bearing capacity,ductility,stiffness degradation of cylinder block.Irregular hole forms a weak position,although a number of measures are taken,the bearing capacity of support tube is still obviously decreased.Therefore,minimizing openings in the short wall is necessary and the same section should not have more than one hole.%大连国际会议中心工程以平面分布不规则的14个筒体为整个工程结构水平和竖向主要支承构件。由于结构形式的特殊性,筒体受力形式有别于传统高层建筑结构中的核心筒。为满足抗震设计及结构连接构造的需要,工程采用内藏带斜支撑型钢桁架混凝土组合筒体,并针对受力特点采取必要的构造措施。为深入研究

  20. 21 CFR 868.5800 - Tracheostomy tube and tube cuff.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Tracheostomy tube and tube cuff. 868.5800 Section... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5800 Tracheostomy tube and tube cuff. (a) Identification. A tracheostomy tube and tube cuff is a device intended to be placed into...

  1. Capacitance of circular patch resonator

    International Nuclear Information System (INIS)

    In this paper the capacitance of the circular microstrip patch resonator is computed. It is shown that the electrostatic problem can be formulated as a system of dual integral equations, and the most interesting techniques of solutions of these systems are reviewed. Some useful approximated formulas for the capacitance are derived and plots of the capacitance are finally given in a wide range of dielectric constants

  2. Capacitance of circular patch resonator

    Energy Technology Data Exchange (ETDEWEB)

    Miano, G.; Verolino, L. [Dip. di Ingegneria Elettrica, Ist. Nazionale di Fisica Nucleare, Naples (Italy); Panariello, G. [Dip. di Ingegneria Elettronica, Naples (Italy); Vaccaro, V.G. [Ist. Nazionale di Fisica Nucleare, Naples (Italy). Dipt. di Scienze Fisiche

    1995-11-01

    In this paper the capacitance of the circular microstrip patch resonator is computed. It is shown that the electrostatic problem can be formulated as a system of dual integral equations, and the most interesting techniques of solutions of these systems are reviewed. Some useful approximated formulas for the capacitance are derived and plots of the capacitance are finally given in a wide range of dielectric constants.

  3. Longitudinal motion in circular accelerators

    International Nuclear Information System (INIS)

    A general description is given of the longitudinal motion of an idealized synchronous particle, exactly in step with the radiofrequency field of a circular accelerator, and a domain in phase and energy, called a bucket, around this particle within which particles are focused around the synchronous particle. This general picture is then made more precise and quantitative. The equations of longitudinal motion and their solutions and the resulting motion are discussed, followed by applications and amplication of the theory. 7 refs., 8 figs

  4. Heat exchanger tube tool

    International Nuclear Information System (INIS)

    Certain types of heat-exchangers have tubes opening through a tube sheet to a manifold having an access opening offset from alignment with the tube ends. A tool for inserting a device, such as for inspection or repair, is provided for use in such instances. The tool is formed by a flexible guide tube insertable through the access opening and having an inner end provided with a connector for connection with the opening of the tube in which the device is to be inserted, and an outer end which remains outside of the chamber, the guide tube having adequate length for this arrangement. A flexible transport hose for internally transporting the device slides inside of the guide tube. This hose is long enough to slide through the guide tube, into the heat-exchanger tube, and through the latter to the extent required for the use of the device. The guide tube must be bent to reach the end of the heat-exchanger tube and the latter may be constructed with a bend, the hose carrying anit-friction elements at interspaced locations along its length to make it possible for the hose to negotiate such bends while sliding to the location where the use of the device is required

  5. Analytical model of the pulse tube engine

    International Nuclear Information System (INIS)

    The pulse tube engine represents the thermodynamic inversion of the pulse tube refrigerator used in cryogenic cooling applications. It has a high potential to be used as a prime mover for the conversion of low grade waste heat into mechanical or electrical energy. This paper describes an analytical analysis of the pulse tube engine based on a zero-dimensional model. During compression and expansion, the engine components are considered as isothermal with characteristic temperatures. At the piston's dead centers, a thermal relaxation model is used to switch between these temperatures. Analytical relations for the pV–work developed by the pulse tube engine and its efficiency are derived. The irreversible nature of the pulse tube engine is studied by calculating the entropy production in the components. Furthermore, the thermodynamic cycle is investigated analytically under variation of design features and operating conditions. The results are compared to prior numerical studies. The minimal temperature ratio above which the engine provides a work output is derived analytically and compared to experimental observations. Fundamental characteristics and application limitations of the pulse tube engine are disclosed. An upper limit for the efficiency of the pulse tube engine is derived theoretically and confirmed experimentally as well as through numerically calculations. - Highlights: • An analytical expression for the pV-work of the pulse tube engine is derived. • The irreversible nature of the pulse tube engine is shown mathematically. • The temperature ratio above which the engine operates is calculated and measured. • An upper limit for the pulse tube engine's efficiency is derived

  6. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... NEI YouTube Videos > NEI YouTube Videos: Amblyopia NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration ... Retinopathy of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia NEI on Twitter NEI on YouTube ...

  7. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... YouTube Videos > NEI YouTube Videos: Amblyopia NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration Amblyopia ... of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia NEI on Twitter NEI on YouTube NEI ...

  8. Circular Polarization in Pulsar Integrated Profiles: Updates

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    We update the systematic studies of circular polarization in integrated pulse profiles by Han et al. Data of circular polarization profiles are compiled. Sense reversals can occur in core or cone components, or near the intersection between components. The correlation between the sense of circular polarization and the sense of position angle variation for conal-double pulsars is confirmed with a much large database. Circular polarization of some pulsars has clear changes with frequency.Circular polarization of millisecond pulsars is marginally different from that of normal pulsars.

  9. Total positive curvature of circular DNA

    DEFF Research Database (Denmark)

    Bohr, Jakob; Olsen, Kasper Wibeck

    2013-01-01

    micro-DNAs longer than the minimum length must be concave, a result that is consistent with typical atomic force microscopy images of plasmids. Predictions for the total positive curvature of circular micro-DNAs are given as a function of length, and comparisons with circular DNAs from the literature...... molecules, e.g., plasmids, it is shown to have implications for the total positive curvature integral. For small circular micro-DNAs it follows as a consequence of Fenchel's inequality that there must exist a minimum length for the circular plasmids to be double stranded. It also follows that all circular...

  10. The effect of tube-support interaction on the dynamic response of heat exchanger tubes

    International Nuclear Information System (INIS)

    As a part of ANL's Flow-Induced Vibration Program in support of the Clinch River Breeder Reactor Plant (CRBRP) steam generator design activity, tube/support interaction experiments are being performed not only to gain the insight into the dynamic behavior of CRBRP steam generator tubes, but also to provide the basis for developing design guidance. In the experiment, the tube and supports are prototypic, the tube spans nearly prototypic, and overall length approximately one-third that of a straight tube segment of the CRBRP steam generator. The test model features a 15.88 mm dia.x3.18 mm thick x 5.08 m long tube (2-1/4% Cr - 1% Mo) surrounded by water, a 101.60 mm thick tubesheet, seven 25.44 mm thick stainless steel supports with 0.254 mm tube-to-support hole clearances and two closely-spaced supports adjacent to the excitation span. The tube is excited by electromagnetic coils simulating crossflow excitation; two displacement transducers, orthogonal to one another, are positioned at the center of each span. Tube response of the midspan locations were measured as a function of various input excitation levels and frequencies. Test results were compared with analytical results based on multispan tube with 'knife-edge' supports at the support locations. Test results show that the resonant frequencies are close to those of the analytical results; experimental modes are in good agreement with analytical predictions or the tube/support configuration tested, peak displacement amplitudes are always lower than those of analytical results; closely-spaced double supports do not effectively dampen out the vibration responses of the adjacent spans and significant orbital motions exist in the spans away from the excitation. It is concluded that a mathematical model assuming a multi-span beam fixed at the tubesheet with intermediate 'knife-edge' supports satisfactorily predicts natural frequencies and mode shapes for the tube/support configuration studied

  11. Oil shale generators with circular retorting chamber

    International Nuclear Information System (INIS)

    The method of semi-coking oil shale in the circular retorting chamber makes it possible to ensure a more uniform distribution of the heat carriers gas across the shale bed, than in the vertically placed retorting chambers with cross-current heat carrier flow, and in the generators using the counter-current method of heat exchange. This also ensures the most favourable conditions for effective heat transfer in the retorting chamber from the gas flow to the shale bed due to the following factors: absence of the lateral outer walls in the retorting chamber; the concentrical arrangement of the retorting chamber and the passage of the gaseous heat carrier through the shale bed from the periphery of the retort to its center; the bulk of the oil shale charged passes through the hot part of the retorting chamber (i.e. on the side of inlet of the gaseous heat carrier into the shale bed). As a result, processing the oil shale in the generators with circular retorting chambers leads to a decrease in the temperature of oil vapours at the gas outlet on an average from 220 to 150o C and the reduction of the specific air consumption for the process - from 360 to 250 m3/t. According to the calculated data, it ensures an increase in oil yield from 78 to 84% of the Fischer assay oil. The application of the circular retorting chamber in the generators, creates conditions for increased unit throughput rates of the retorts 1.5-2.0 times with a simultaneous increase in the oil yield. For processing oil shales rich in organic material, which readily bitumenize, retorts for a throughput of 1500 tonnes per day have been developed and are already under construction at the P O 'Slantsekhim'. Project designs for the leaner shales can be developed for throughput rates in excess of 5000-6000 tonnes per day. The retorts will have a comparatively small diameter and a simpler design than the 1000 t/day generators being now in operation. (author). 14 refs., 2 tabs., fig

  12. Pediatric cuffed endotracheal tubes

    Directory of Open Access Journals (Sweden)

    Neerja Bhardwaj

    2013-01-01

    Full Text Available Endotracheal intubation in children is usually performed utilizing uncuffed endotracheal tubes for conduct of anesthesia as well as for prolonged ventilation in critical care units. However, uncuffed tubes may require multiple changes to avoid excessive air leak, with subsequent environmental pollution making the technique uneconomical. In addition, monitoring of ventilatory parameters, exhaled volumes, and end-expiratory gases may be unreliable. All these problems can be avoided by use of cuffed endotracheal tubes. Besides, cuffed endotracheal tubes may be of advantage in special situations like laparoscopic surgery and in surgical conditions at risk of aspiration. Magnetic resonance imaging (MRI scans in children have found the narrowest portion of larynx at rima glottides. Cuffed endotracheal tubes, therefore, will form a complete seal with low cuff pressure of <15 cm H 2 O without any increase in airway complications. Till recently, the use of cuffed endotracheal tubes was limited by variations in the tube design marketed by different manufacturers. The introduction of a new cuffed endotracheal tube in the market with improved tracheal sealing characteristics may encourage increased safe use of these tubes in clinical practice. A literature search using search words "cuffed endotracheal tube" and "children" from 1980 to January 2012 in PUBMED was conducted. Based on the search, the advantages and potential benefits of cuffed ETT are reviewed in this article.

  13. Cytoskeleton in Pollen and Pollen Tubes of Ginkgo biloba L.

    Institute of Scientific and Technical Information of China (English)

    Jun-Mei LIU; Hong ZHANG; Yan LI

    2005-01-01

    The distribution of F-actin and microtubules was investigated in pollen and pollen tubes of Ginkgo biloba L. using a confocal laser scanning microscope after fluorescence and immunofluorescence labeling. A dense F-actin network was found in hydrated Ginkgo pollen. When Ginkgo pollen was germinating,F-actin mesh was found under the plasma membrane from which the pollen tube would emerge. After pollen germination, F-actin bundles were distributed axially in long pollen tubes of G. biloba. Thick F-actin bundles and network were found in the tip of the Ginkgo pollen tube, which is opposite to the results reported for the pollen tubes of some angiosperms and conifers. In addition, a few circular F-actin bundles were found in Ginkgo pollen tubes. Using immunofluorescence labeling, a dense microtubule network was found in hydrated Ginkgo pollen under confocal microscope. In the Ginkgo pollen tube, the microtubules were distributed along the longitudinal axis and extended to the tip. These results suggest that the cytoskeleton may have an essential role in the germination of Ginkgo pollen and tube growth.

  14. Improved Traveling-Wave Tube

    Science.gov (United States)

    Rousseau, Art; Tammaru, Ivo; Vaszari, John

    1988-01-01

    New space traveling-wave tube (TWT) provides coherent source of 75 watts of continuous-wave power output over bandwidth of 5 GHz at frequency of 65 GHz. Coupled-cavity TWT provides 50 dB of saturated gain. Includes thermionic emitter, M-type dispenser cathode providing high-power electron beam. Beam focused by permanent magnets through center of radio-frequency cavity structure. Designed for reliable operation for 10 years, and overall efficiency of 35 percent minimizes prime power input and dissipation of heat.

  15. Reconfigurable Plasma Antenna Array by Using Fluorescent Tube for Wi-Fi Application

    Directory of Open Access Journals (Sweden)

    H. Ja’afar

    2016-06-01

    Full Text Available This paper presents a new design of reconfigurable plasma antenna array using commercial fluorescent tube. A round shape reconfigurable plasma antenna array is proposed to collimate beam radiated by an omnidirectional antenna (monopole antenna operates at 2.4GHz in particular direction. The antenna design is consisted of monopole antenna located at the center of circular aluminum ground. The monopole antenna is surrounded by a cylindrical shell of conducting plasma. The plasma shield consists of 12 commercial fluorescent tubes aligned in series containing a mixture of Argon gas and mercury vapor which upon electrification forms plasma columns. The plasma behaves as a conductor and acts as a reflector in radiation, in the condition where plasma frequency,ωp is higher than operating frequency. From this concepts, when all plasma elements are activated or switched to ON, the radiation signal from monopole antenna will trapped inside the plasma blanket and meanwhile when one or more plasma elements is deactivated (switched OFF, the radiation from monopole antenna will escape. This antenna has the capability to change its patterns with beam direction at 0°, 30°, 60°, 90°, 120°, 150°, 180°, 210°, 240°, 270°, 300° and 330° at frequency 2.4 GHz. The proposed antenna has been successfully fabricated and measured with conclusive results.

  16. Local Heat Transfer for Finned-Tube Heat Exchangers using Oval Tubes

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, James Edward; Sohal, Manohar Singh

    2000-08-01

    This paper presents the results of an experimental study of forced convection heat transfer in a narrow rectangular duct fitted with either a circular tube or an elliptical tube in crossflow. The duct was designed to simulate a single passage in a fin-tube heat exchanger. Heat transfer measurements were obtained using a transient technique in which a heated airflow is suddenly introduced to the test section. High-resolution local fin-surface temperature distributions were obtained at several times after initiation of the transient using an imaging infrared camera. Corresponding local fin-surface heat transfer coefficient distributions were then calculated from a locally applied one-dimensional semi-infinite inverse heat conduction model. Heat transfer results were obtained over an airflow rate ranging from 1.56 x 10-3 to 15.6 x 10-3 kg/s. These flow rates correspond to a duct-height Reynolds number range of 630 – 6300 with a duct height of 1.106 cm and a duct width-toheight ratio, W/H, of 11.25. The test cylinder was sized such that the diameter-to-duct height ratio, D/H is 5. The elliptical tube had an aspect ratio of 3:1 and a/H equal to 4.33. Results presented in this paper reveal visual and quantitative details of local fin-surface heat transfer distributions in the vicinity of circular and oval tubes and their relationship to the complex horseshoe vortex system that forms in the flow stagnation region. Fin surface stagnation-region Nusselt numbers are shown to be proportional to the square-root of Reynolds number.

  17. CFD simulation of the gas flow in a pulse tube cryocooler with two pulse tubes

    Science.gov (United States)

    Yin, C. L.

    2015-12-01

    In this paper, in order to instruct the next optimization work, a two-dimension Computational Fluid Dynamics (CFD) model is developed to simulate temperature distribution and velocity distribution of oscillating fluid in the DPTC by individual phase-shifting. It is found that the axial temperature distribution of regenerator is generally uniform and the temperatures near the center at the same cross setion of two pulse tubes are obviously higher than their near wall temperatures. The wall temperature difference about 0-7 K exists between the two pulse tubes. The velocity distribution near the center of the regenerator is uniform and there is obvious injection stream coming at the center of the pulse tubes from the hot end. The formation reason of temperature distribution and velocity distribution is explained.

  18. Conduction cooled tube supports

    Science.gov (United States)

    Worley, Arthur C.; Becht, IV, Charles

    1984-01-01

    In boilers, process tubes are suspended by means of support studs that are in thermal contact with and attached to the metal roof casing of the boiler and the upper bend portions of the process tubes. The support studs are sufficiently short that when the boiler is in use, the support studs are cooled by conduction of heat to the process tubes and the roof casing thereby maintaining the temperature of the stud so that it does not exceed 1400.degree. F.

  19. Tubing weld cracking test

    International Nuclear Information System (INIS)

    A tubing weld cracking (TWC) test was developed for applications involving advanced austenitic alloys (such as modified 800H and 310HCbN). Compared to the Finger hot cracking test, the TWC test shows an enhanced ability to evaluate the crack sensitivity of tubing materials. The TWC test can evaluate the cracking tendency of base as well as filter materials. Thus, it is a useful tool for tubing suppliers, filler metal producers and fabricators

  20. Deterministic Circular Self Test Path

    Institute of Scientific and Technical Information of China (English)

    WEN Ke; HU Yu; LI Xiaowei

    2007-01-01

    Circular self test path (CSTP) is an attractive technique for testing digital integrated circuits(IC) in the nanometer era, because it can easily provide at-speed test with small test data volume and short test application time. However, CSTP cannot reliably attain high fault coverage because of difficulty of testing random-pattern-resistant faults. This paper presents a deterministic CSTP (DCSTP) structure that consists of a DCSTP chain and jumping logic, to attain high fault coverage with low area overhead. Experimental results on ISCAS'89 benchmarks show that 100% fault coverage can be obtained with low area overhead and CPU time, especially for large circuits.

  1. An iterative neighborhood search approach for minimum zone circularity evaluation from coordinate measuring machine data

    International Nuclear Information System (INIS)

    An iterative neighborhood search approach (INSA) was proposed to precisely evaluate the circularity error under minimum zone conditions without directly solving nonlinear equations from coordinate measurement machine (CMM) data. The method starts with calculating the initial location and radius of an initial circular search scope. The location is the center of the circle based on an approximate least-squares method of all measurement data points uniformly sampled around the circle, and the radius is the circularity error value by using the approximate center as the datum center of two concentric circles enclosing all measurement data points. Then the circular search scope was divided according to some concentric circles and radials with some radius and angle step lengths. Intersections of the circles and radials were candidate centers for circularity evaluation under the minimum zone criteria. An optimal center with minimum circularity error value was picked out as a new location of the search scope. The distance from the old location was the radius of the new search scope. Further it was divided and the intersections were evaluated until the optimal solution was met. Some examples in the literature were used to verify the validity of this method. The results are the same as or better than those minimum zone solutions adopted from previous work, and computation time is no more than 0.07 s implementing on an IBM ThinkPad R40 laptop for all examples. The computation and comparison show that the proposed INSA is a precise, fast, convergent and simple approach which solved circularity evaluation problems effectively. (technical design note)

  2. Categorising YouTube

    OpenAIRE

    Thomas Mosebo Simonsen

    2011-01-01

    This article provides a genre analytical approach to creating a typology of the User Generated Content (UGC) of YouTube. The article investigates the construction of navigation processes on the YouTube website. It suggests a pragmatic genre approach that is expanded through a focus on YouTube’s technological affordances. Through an analysis of the different pragmatic contexts of YouTube, it is argued that a taxonomic understanding of YouTube must be analysed in regards to the vacillation of a...

  3. Calibrations of photomultiplier tubes

    International Nuclear Information System (INIS)

    The experimental methods for calibration photomultiplier tubes used in the multichannel fast-pulse-detection system of Thomson scattering measurements for nuclear fusion devices is reported. The most important parameters of the photomultiplier tubes to be calibrated include: linearity of output electric signals to input light signals, response time of pulsed light, spectral response, absolute responsibility, and sensitivity as a function of the chain voltage. The calibrations of all these parameters are carried out by using EMI 9558 B and RCA 7265 photomultiplier tubes respectively. The experimental methods presented in the paper are common to those quantitative measurements that require phomultiplier tubes as detectors

  4. Composite Pulse Tube

    Science.gov (United States)

    Martin, Jerry L.; Cloyd, Jason H.

    2007-01-01

    A modification of the design of the pulse tube in a pulse-tube cryocooler reduces axial thermal conductance while preserving radial thermal conductance. It is desirable to minimize axial thermal conductance in the pulse-tube wall to minimize leakage of heat between the warm and cold ends of the pulse tube. At the same time, it is desirable to maximize radial thermal conductance at the cold end of the pulse tube to ensure adequate thermal contact between (1) a heat exchanger in the form of a stack of copper screens inside the pulse tube at the cold end and (2) the remainder of the cold tip, which is the object to which the heat load is applied and from which heat must be removed. The modified design yields a low-heat-leak pulse tube that can be easily integrated with a cold tip. A typical pulse tube of prior design is either a thin-walled metal tube or a metal tube with a nonmetallic lining. It is desirable that the outer surface of a pulse tube be cylindrical (in contradistinction to tapered) to simplify the design of a regenerator that is also part of the cryocooler. Under some conditions, it is desirable to taper the inner surface of the pulse tube to reduce acoustic streaming. The combination of a cylindrical outer surface and a tapered inner surface can lead to unacceptably large axial conduction if the pulse tube is made entirely of metal. Making the pulse-tube wall of a nonmetallic, lowthermal- conductivity material would not solve the problem because the wall would not afford the needed thermal contact for the stack of screens in the cold end. The modified design calls for fabricating the pulse tube in two parts: a longer, nonmetallic part that is tapered on the inside and cylindrical on the outside and a shorter, metallic part that is cylindrical on both the inside and the outside. The nonmetallic part can be made from G-10 fiberglass-reinforced epoxy or other low-thermal-conductivity, cryogenically compatible material. The metallic part must have high

  5. Manual tube welding torch

    International Nuclear Information System (INIS)

    In a welding torch which fits over a tube intermediate the ends thereof for welding the juncture between the tube and a boss on the back side of a tube plate, a split housing encloses a tungsten electrode, a filler wire duct and a fiber optic bundle arranged to observe the welding process. A shielding gas duct is provided in the housing. A screw is provided for setting electrode/work distance. Difficult remote tube welding operations can be performed with the apparatus. (author)

  6. Steam generator tube performance

    International Nuclear Information System (INIS)

    A survey of steam generator operating experience for 1986 has been carried out for 184 pressurized water and pressurized heavy-water reactors, and 1 water-cooled, graphite-moderated reactor. Tubes were plugged at 75 of the reactors (40.5%). In 1986, 3737 tubes were plugged (0.14% of those in service) and 3148 tubes were repaired by sleeving. A small number of reactors accounted for the bulk of the plugged tubes, a phenomenon consistent with previous years. For 1986, the available tubesheet sludge data for 38 reactors has been compiled into tabular form, and sludge/deposit data will be incorporated into all future surveys

  7. Physics at Future Circular Colliders

    Science.gov (United States)

    Kotwal, Ashutosh

    2016-03-01

    The Large Hadron Collider has been a grand success with the discovery of the Higgs boson, with bright prospects for additional discoveries since the recent increase in collider energy and the anticipated large datasets. Big open questions such as the nature of dark matter, the origin of the matter-antimatter asymmetry in the Universe, and the theoretical puzzle of the finely-tuned parameters in the Higgs sector, demand new physics principles that extend the established Standard Model paradigm. Future circular colliders in a substantially larger tunnel can house both a high luminosity electron-positron collider for precision measurements of Higgs and electroweak parameters, as well as a very high energy proton-proton collider which can directly manifest particles associated with these new physics principles. We discuss the physics goals of these future circular colliders, and the prospects for elucidating fundamental new laws of nature that will significantly extend our understanding of the Universe. Detailed studies of the discovery potential in specific benchmark models will be presented, with implications for detector design.

  8. Steam generator tube failures

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, P.E.; Shah, V.N.; Ward, L.W.; Ellison, P.G.

    1996-04-01

    A review and summary of the available information on steam generator tubing failures and the impact of these failures on plant safety is presented. The following topics are covered: pressurized water reactor (PWR), Canadian deuterium uranium (CANDU) reactor, and Russian water moderated, water cooled energy reactor (VVER) steam generator degradation, PWR steam generator tube ruptures, the thermal-hydraulic response of a PWR plant with a faulted steam generator, the risk significance of steam generator tube rupture accidents, tubing inspection requirements and fitness-for-service criteria in various countries, and defect detection reliability and sizing accuracy. A significant number of steam generator tubes are defective and are removed from service or repaired each year. This wide spread damage has been caused by many diverse degradation mechanisms, some of which are difficult to detect and predict. In addition, spontaneous tube ruptures have occurred at the rate of about one every 2 years over the last 20 years, and incipient tube ruptures (tube failures usually identified with leak detection monitors just before rupture) have been occurring at the rate of about one per year. These ruptures have caused complex plant transients which have not always been easy for the reactor operators to control. Our analysis shows that if more than 15 tubes rupture during a main steam line break, the system response could lead to core melting. Although spontaneous and induced steam generator tube ruptures are small contributors to the total core damage frequency calculated in probabilistic risk assessments, they are risk significant because the radionuclides are likely to bypass the reactor containment building. The frequency of steam generator tube ruptures can be significantly reduced through appropriate and timely inspections and repairs or removal from service.

  9. Steam generator tube failures

    International Nuclear Information System (INIS)

    A review and summary of the available information on steam generator tubing failures and the impact of these failures on plant safety is presented. The following topics are covered: pressurized water reactor (PWR), Canadian deuterium uranium (CANDU) reactor, and Russian water moderated, water cooled energy reactor (VVER) steam generator degradation, PWR steam generator tube ruptures, the thermal-hydraulic response of a PWR plant with a faulted steam generator, the risk significance of steam generator tube rupture accidents, tubing inspection requirements and fitness-for-service criteria in various countries, and defect detection reliability and sizing accuracy. A significant number of steam generator tubes are defective and are removed from service or repaired each year. This wide spread damage has been caused by many diverse degradation mechanisms, some of which are difficult to detect and predict. In addition, spontaneous tube ruptures have occurred at the rate of about one every 2 years over the last 20 years, and incipient tube ruptures (tube failures usually identified with leak detection monitors just before rupture) have been occurring at the rate of about one per year. These ruptures have caused complex plant transients which have not always been easy for the reactor operators to control. Our analysis shows that if more than 15 tubes rupture during a main steam line break, the system response could lead to core melting. Although spontaneous and induced steam generator tube ruptures are small contributors to the total core damage frequency calculated in probabilistic risk assessments, they are risk significant because the radionuclides are likely to bypass the reactor containment building. The frequency of steam generator tube ruptures can be significantly reduced through appropriate and timely inspections and repairs or removal from service

  10. 77 FR 64473 - Circular Welded Carbon-Quality Steel Pipe From the Sultanate of Oman: Final Affirmative...

    Science.gov (United States)

    2012-10-22

    ..., 77 FR 19635 (April 2, 2012) (``Preliminary Determination''). We received comments from Wheatland Tube...\\ See Antidumping Duties; Countervailing Duties, 62 FR 27296, 27323 (May 19, 1997) and Circular Welded... Republic of Vietnam: Initiation of Countervailing Duty Investigations, 76 FR 72173 (November 22,...

  11. 75 FR 44763 - Certain Circular Welded Non-Alloy Steel Pipe From Mexico; Extension of Time Limit for Preliminary...

    Science.gov (United States)

    2010-07-29

    ... and Request for Revocation in Part, 74 FR 68229 (December 23, 2009). The current deadline for the... International Trade Administration Certain Circular Welded Non-Alloy Steel Pipe From Mexico; Extension of Time... Department) received a timely request from domestic interested parties Allied Tube and Conduit...

  12. 75 FR 34980 - Circular Welded Non-Alloy Steel Pipe from the Republic of Korea: Final Results of the Antidumping...

    Science.gov (United States)

    2010-06-21

    ... Welded Non-Alloy Steel Pipe and Tube From Brazil, the Republic of Korea, Mexico, and Venezuela, 61 FR... Sales at Less Than Fair Value: Certain Circular Welded Non-Alloy Steel Pipe from Korea, 57 FR 49453... Korea: Preliminary Results and Rescission in Part of the Antidumping Duty Administrative Review, 74...

  13. Mixing in Circular and Non-circular Jets in Crossflow

    DEFF Research Database (Denmark)

    Salewski, Mirko; Stankovic, D.; Fuchs, L.

    2008-01-01

    are compared for circular, elliptic, and square nozzles. For the latter configurations, effects of orientation are considered. The computations reveal that the distribution of a passive scalar in a cross-sectional plane can be single- or double-peaked, depending on the nozzle shape and orientation. A proper...... orthogonal decomposition of the transverse velocity indicates that coherent structures may be responsible for this phenomenon. Nozzles which have a single-peaked distribution have stronger modes in transverse direction. The global mixing performance is superior for these nozzle types. This is the case...... for the blunt square nozzle and for the elliptic nozzle with high aspect ratio. It is further demonstrated that the flow field contains large regions in which a passive scalar is transported up the mean gradient (counter-gradient transport) which implies failure of the gradient diffusion hypothesis....

  14. CIRCULAR ECONOMY IN ROMANIA WITHIN EUROPEAN CONTEXT

    OpenAIRE

    Cornelia Marcela Danu; Valentin Nedeff

    2015-01-01

    In the present paper we have approached some conceptual and coordinated marks of the societal reality connected to the circular economy. Generated by „the limits of certainty” regarding the future of the world business, the operationalization of the circular economy has become a part of the EU strategies and started the various stages of implementation as an active process in all countries. We have highlighted the opportunities and the risks related to the circular economy, the European dimen...

  15. A COMPACT CIRCULARLY POLARIZED SLOTTED MICROSTRIP ANTENNA

    OpenAIRE

    V. Jebaraj; K.R.S. Ravi Kumar; D. Mohanageetha

    2014-01-01

    Slot antennas are often used at UHF and microwave frequencies. In slot antenna for RFID reader applications the frequency ranges from 902-923MHz to achieve circular polarization. The shapes and size of the slot, as well as the driving frequency, determine the radiation distribution pattern. The proposed compact size circularly polarized slotted microstrip antenna are summarized with design rules. The circularly polarized radiation in square patch antenna can be obtained by perturbation techni...

  16. Reconfigurable Monopole Antennas With Circular Polarization

    OpenAIRE

    Panahi, Afshin

    2015-01-01

    This thesis presents research on printed circularly-polarized monopole antennas and their application in reconfigurable monopole antennas. The proposed circularly-polarised monopole antennas benefit from advantages such as small size, low-cost, low-profile and simple designs. The first part of this thesis introduces three printed circularly-polarized monopole antennas for global navigation satellite systems and Wi-Fi applications. The primary focus is on the ground plane which is used as a ra...

  17. Pyrotechnic Tubing Connector

    Science.gov (United States)

    Graves, Thomas J.; Yang, Robert A.

    1988-01-01

    Tool forms mechanical seal at joint without levers or hydraulic apparatus. Proposed tool intended for use in outer space used on Earth by heavily garbed workers to join tubing in difficult environments. Called Pyrotool, used with Lokring (or equivalent) fittings. Piston slides in cylinder when pushed by gas from detonating pyrotechnic charge. Impulse of piston compresses fittings, sealing around butting ends of tubes.

  18. Welding Tubes In Place

    Science.gov (United States)

    Meredith, R.

    1984-01-01

    Special welding equipment joins metal tubes that carry pressurized cyrogenic fluids. Equipment small enough to be used in confined spaces in which such tubes often mounted. Welded joints lighter in weight and more leak-proof than joints made with mechanical fittings.

  19. Circular Samples as Objects for Magnetic Resonance Imaging - Mathematical Simulation, Experimental Results

    Science.gov (United States)

    Frollo, Ivan; Krafčík, Andrej; Andris, Peter; Přibil, Jiří; Dermek, Tomáš

    2015-12-01

    Circular samples are the frequent objects of "in-vitro" investigation using imaging method based on magnetic resonance principles. The goal of our investigation is imaging of thin planar layers without using the slide selection procedure, thus only 2D imaging or imaging of selected layers of samples in circular vessels, eppendorf tubes,.. compulsorily using procedure "slide selection". In spite of that the standard imaging methods was used, some specificity arise when mathematical modeling of these procedure is introduced. In the paper several mathematical models were presented that were compared with real experimental results. Circular magnetic samples were placed into the homogenous magnetic field of a low field imager based on nuclear magnetic resonance. For experimental verification an MRI 0.178 Tesla ESAOTE Opera imager was used.

  20. Molecular alignment using circularly polarized laser pulses

    CERN Document Server

    Smeenk, C T L

    2013-01-01

    We show that circularly polarized femtosecond laser pulses produce field-free alignment in linear and planar molecules. We study the rotational wavepacket evolution of O$_2$ and benzene created by circularly polarized light. For benzene, we align the molecular plane to the plane of polarization. For O$_2$, we demonstrate that circular polarization yields a net alignment along the laser propagation axis at certain phases of the evolution. Circular polarization gives us the ability to control alignment of linear molecules outside the plane of polarization, providing new capabilities for molecular imaging.

  1. Turbulence-induced secondary motion in a buoyancy-driven flow in a circular pipe

    OpenAIRE

    Hallez, Yannick; Magnaudet, Jacques

    2009-01-01

    We analyze the results of a direct numerical simulation of the turbulent buoyancy-driven flow that sets in after two miscible fluids of slightly different densities have been initially superimposed in an unstable configuration in an inclined circular pipe closed at both ends. In the central region located midway between the end walls, where the flow is fully developed, the resulting mean flow is found to exhibit nonzero secondary velocity components in the tube cross section. We present a det...

  2. Thickness-shear vibration of a circular cylindrical ceramic cylinder with unattached electrodes and air gaps

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    We analyze thickness-shear vibration of an axially poled circular cylindrical tube with unattached electrodes and air gaps. Both free and electrically forced vibrations are studied. Exact solutions are obtained from the equations of linear piezoelectricity. Resonant frequencies and the impedance of the transducer are calculated from the solution. Results show that the resonant frequencies are sensitive to the dimensions of the air gaps when the gaps are thin. The impedance depends strongly on the air gaps.

  3. Nonlocal theory of sound propagation in porous media: case of circular pores

    OpenAIRE

    Nemati, Navid; Lafarge, Denis

    2013-01-01

    Elaborating on a Maxwellian representation of longitudinal wave propagation in a viscothermal fluid, a general nonlocal macroscopic theory of sound propagation in homogeneous porous media saturated with a viscothermal fluid has been recently proposed. The present paper validates this new nonlocal Maxwellian theory by showing that, in the case of the propagation in straight circular tubes, it is in complete agreement with the long known Kirchhoff-Langevin's full solutions.

  4. Elastic unloading of a disk after plastic deformation by a circular heat source

    International Nuclear Information System (INIS)

    Subject of the investigation is the transient stress distribution in an elastic-plastic disk acted upon by a circular heat source. The disk serves as a mechanical model of the rotating anode of an X-ray-tube. The calculation is based on Tresca's yield criterion and the flow rule associatd to it. During heating, a plastic region spreads around the source, which is absorbed by an unloaded zone after the removal of the source. (orig.)

  5. Categorising YouTube

    DEFF Research Database (Denmark)

    Simonsen, Thomas Mosebo

    2011-01-01

    This article provides a genre analytical approach to creating a typology of the User Generated Content (UGC) of YouTube. The article investigates the construction of navigation processes on the YouTube website. It suggests a pragmatic genre approach that is expanded through a focus on YouTube’s...... technological affordances. Through an analysis of the different pragmatic contexts of YouTube, it is argued that a taxonomic understanding of YouTube must be analysed in regards to the vacillation of a user-driven bottom-up folksonomy and a hierarchical browsing system that emphasises a culture of competition...... and which favours the already popular content of YouTube. With this taxonomic approach, the UGC videos are registered and analysed in terms of empirically based observations. The article identifies various UGC categories and their principal characteristics. Furthermore, general tendencies of the UGC...

  6. TRIPLET CIRCULAR HOUGH TRANSFORM FOR CIRCLE DETECTION

    Institute of Scientific and Technical Information of China (English)

    LuoDaisheng; HeXiaohai; 等

    2002-01-01

    A new method,triplet circular Hough transform,is proposed for circle detection in image processing and pattern recognition.In the method,a curve in an image is first detected.Next,a sequence of three points on the curve are selected.a sequence of parameters(a,b,r)corresponding to the three points are calculated by solving the circle equation of the curve,and two 2-D accumulators A(a,b)and R(a,b)are accumulated with 1 and r,respectively,Then the parameters{(a,b,r)}of the circles fitting the curve are determined from A(a,b)and R(a,b) by searching for the local maximum over A(a,b).Because no computation loops over center(a,b) and/or radius r are needed,the method is faster than the basic and directional gradient methods It needs also much smaller memory for accumulation.

  7. Digital Radiography Qualification of Tube Welding

    Science.gov (United States)

    Carl, Chad

    2012-01-01

    The Orion Project will be directing Lockheed Martin to perform orbital arc welding on commodities metallic tubing as part of the Multi Purpose Crew Vehicle assembly and integration process in the Operations and Checkout High bay at Kennedy Space Center. The current method of nondestructive evaluation is utilizing traditional film based x-rays. Due to the high number of welds that are necessary to join the commodities tubing (approx 470), a more efficient and expeditious method of nondestructive evaluation is desired. Digital radiography will be qualified as part of a broader NNWG project scope.

  8. La raó circular

    OpenAIRE

    Pinyol i Bori, Francesc

    2007-01-01

    És un text epistemològic sobre les qüestions cognitives circulars que apareixen: a) Quan el subjecte forma part de l'objecte estudiat; b) En la recerca de les bases del coneixement; c) Al voler justificar la inducció; d) En algunes interpretacions filosòfiques i científiques. S'hi explica l'estat del punt a) el més problemàtic, i s'aclareixen els altres tres punts: els b) i c) pel fet científic que l'evolució cognitiva humana ha anat acoblada a l'evolució biològica, la qual ha generat els a p...

  9. Power Transmittance of a Laterally Shifted Gaussian Beam through a Circular Aperture

    CERN Document Server

    Khwaja, Tariq Shamim

    2016-01-01

    Gaussian beams are often used in optical systems. The fundamental Gaussian TEM00 mode is the most common of the Gaussian modes present in various optical devices, systems and equipment. Within an optical system, it is common that this Gaussian TEM00 beam passes through a circular aperture of a finite diameter. Such circular apertures include irises, spatial filters, circular Photo-Detectors (PDs) and optical mounts with circular rims. The magnitude of optical power passing through a finite-sized circular aperture is well-documented for cases where the Gaussian beam passes through the center of the clear circular aperture, and is chopped off symmetrically in all radial directions on a given plane. More often than not, a non-axial incident Gaussian Beam is not blocked in a radially uniform manner by a circular aperture. Such situations arise due to a lateral displacement of the beam from tilted glass blocks, manufacturing errors and imperfect surface flatness or parallelness of surfaces. The fraction of optical...

  10. Pressure tube type reactor

    International Nuclear Information System (INIS)

    Heretofore, a pressure tube type reactor has a problem in that the evaluation for the reactor core performance is complicate and no sufficient consideration is made for the economical property, to increase the size of a calandria tank and make the cost expensive. Then, in the present invention, the inner diameter of a pressure tube is set to greater than 50% of the lattice gap in a square lattice like arrangement, and the difference between the inner and the outer diameters of the calandria tube is set smaller than 20% of the lattice gap. Further, the inner diameter of the pressure tube is set to greater than 40% and the difference between the inner and the outer diameters of the calandria tube is set smaller than 30% of the lattice gap in a triangle lattice arrangement. Then, heavy water-to-fuel volume ratio can be determined appropriately and the value for the coolant void coefficient is made more negative side, to improve the self controllability inherent to the reactor. In particular, when 72 to 90 fuel rods are arranged per one pressure tube, the power density per one fuel rod is can be increased by about twice. Accordingly, the number of the pressure tubes can be reduced about to one-half, thereby enabling to remarkably decrease the diameter of the reactor core and to reduce the size of the calandria, which is economical. (N.H.)

  11. A new multichannel detector for proteomics studies and circular dichroism

    International Nuclear Information System (INIS)

    The conventional instrument for the measurement of Circular Dichroism (CD) comprises of a single anode photomultiplier tube (PMT) detector connected to a 'lock-in' amplifier. This requires the sequential scanning across the wavelength spectrum, making it a useful method for structure determination but not for time-resolved measurements and the observation of structural changes. In this paper, we report on our progress to develop a novel system based on a semiconductor linear array detector that will overcome the limitations of the conventional systems and will allow for the observation of dynamic phenomena to the time limits imposed by the technique itself, i.e. 20 μs with conventional light modulation methods. Our final aim is to develop an instrument that will enable the simultaneous measurement of both spectroscopic and time resolved CD by the realisation of energy-dispersive experiments (EDE-CD)

  12. 3-D NUMERICAL STUDY AND COMPARISON OF ECCENTRIC AND CONCENTRIC ANNULAR-FINNED TUBE HEAT EXCHANGERS

    OpenAIRE

    FAROUK TAHROUR; ABDELMOUMENE HAKIM BENMACHICHE; MOUNIR AKSAS; CHERIF BOUGRIOU

    2015-01-01

    The use of 3-D computational fluid dynamics (CFD) is proposed to simulate the conjugate conduction-convection of heat transfer problems in eccentric annularfinned tube heat exchangers. The numerical simulation results allow us to evaluate the heat transfer coefficient over fin surfaces, the fin efficiency and the pressure drop. The aim of the present paper is to determine the optimum tube position in the circular fin that maximizes heat dissipation and minimizes pressure drop. In addition, th...

  13. Microstrip Antenna Generates Circularly Polarized Beam

    Science.gov (United States)

    Huang, J.

    1986-01-01

    Circular microstrip antenna excited with higher order transverse magnetic (TM) modes generates circularly polarized, conical radiation patterns. Found both theoretically and experimentally that peak direction of radiation pattern is varied within wide angular range by combination of mode selection and loading substrate with materials of different dielectric constants.

  14. Circular Loudspeaker Array with Controllable Directivity

    DEFF Research Database (Denmark)

    Møller, Martin; Olsen, Martin; Agerkvist, Finn T.;

    2010-01-01

    Specific directivity patterns for circular arrays of loudspeakers can be achieved by utilizing the concept of phase-modes, which expands the directivity pattern into a series of circular harmonics. This paper investigates the applicability of this concept applied on a loudspeaker array on a...

  15. Boiling two-phase flow and heat transfer in concentric annular tube

    International Nuclear Information System (INIS)

    The boiling flow resistance and heat transfer characteristics is experimentally investigated under the outer tube wall heating condition in a concentric annular tube with 2.1 mm gap size. The results show that the flow resistance in the annular tube is greater than that in circular tube, as well as the boiling heat transfer becomes enhanced. The heat transfer coefficient has close relationship with the pressure, thermal equilibrium quality, mass flux, heat flux, gap size of the annular tube, and heat models as well. The physical explanation about the enhancement boiling heat transfer in the annular tube is proposed with both micro-film evaporation mechanics and bubble disturbance mechanics. The correlations to calculate the flow friction coefficient and heat transfer coefficient are proposed based on the experimental data. (authors)

  16. CIRCULAR ECONOMY IN ROMANIA WITHIN EUROPEAN CONTEXT

    Directory of Open Access Journals (Sweden)

    Cornelia Marcela Danu

    2015-07-01

    Full Text Available In the present paper we have approached some conceptual and coordinated marks of the societal reality connected to the circular economy. Generated by „the limits of certainty” regarding the future of the world business, the operationalization of the circular economy has become a part of the EU strategies and started the various stages of implementation as an active process in all countries. We have highlighted the opportunities and the risks related to the circular economy, the European dimension and, in particular, the Romanian one of this process, the role of the triad: consumer-company-natural environment, while implementing the circular economy. Circular economy is both a new approach of the societal life, based on changing the mentalities of the individuals having the role of decision makers at the company level and public administration and the decision makers – consumers, as well as a policy meant to be made operational across all entities: governmental, entrepreneurial, individually – human.

  17. Gauge-Invariant Formulation of Circular Dichroism.

    Science.gov (United States)

    Raimbault, Nathaniel; de Boeij, Paul L; Romaniello, Pina; Berger, J A

    2016-07-12

    Standard formulations of magnetic response properties, such as circular dichroism spectra, are plagued by gauge dependencies, which can lead to unphysical results. In this work, we present a general gauge-invariant and numerically efficient approach for the calculation of circular dichroism spectra from the current density. First we show that in this formulation the optical rotation tensor, the response function from which circular dichroism spectra can be obtained, is independent of the origin of the coordinate system. We then demonstrate that its trace is independent of the gauge origin of the vector potential. We also show how gauge invariance can be retained in practical calculations with finite basis sets. As an example, we explain how our method can be applied to time-dependent current-density-functional theory. Finally, we report gauge-invariant circular dichroism spectra obtained using the adiabatic local-density approximation. The circular dichroism spectra we thus obtain are in good agreement with experiment. PMID:27295541

  18. Nanofocusing in circular sector-like nanoantennas

    DEFF Research Database (Denmark)

    Zenin, Volodymyr; Pors, Anders Lambertus; Han, Zhanghua;

    2014-01-01

    Gold circular sector-like nanoantennas (with a radius of 500 nm and a taper angle of 60°, 90°, and 120°) on glass are investigated in a near-infrared wavelength range (900 - 2100 nm). Amplitude- and phase-resolved near-field images of circular sector-like antenna modes at telecom wavelength feature...... a concentric circular line of phase contrast, demonstrating resonant excitation of a standing wave of counter-propagating surface plasmons, travelling between a tip and opposite circular edge of the antenna. Transmission spectra obtained in the range 900 - 2100 nm are in good agreement with...... makes circular sector-like nanoantennas very promising for implementing bowtie antennas and attractive for many applications....

  19. Three dimensional MHD effects studies in a manifold circular pipe

    International Nuclear Information System (INIS)

    Some new experimental results ar carried out in a manifold circular pipe for liquid metal MHD (Magneto-hydrodynamic) fluid flow. The velocity distributions are measured on the center plane of cross section of joint of manifold pipe. The instabilities of vortex street are observed in cross section of the pipe. It is obtained to the expression formula of three-dimensional (3D) additional MHD pressured drop due to the manifold junction. It also is discussed to the affections of 2D effect and non-fully developed flow in the experiment results

  20. Circular filter bag change ladderack system video presentation

    International Nuclear Information System (INIS)

    A great deal of research and development at Harwell over the last few years has centered around the design of circular radial flow HEPA filters as alternatives to the traditional rectangular HEPA filter. With a circular insert there are inherent features which give this geometry certain advantages over its counterpart, such as ease of sealing, compatibility with remote handling and disposal routes; these have been well publicized in previous works. A mock-up is shown of a bag change ladderack system of 3400m3/h circular filter. It highlights the space requirements for bag changing and demonstrates the ease with which a filter may be replaced. The filter throat incorporates a silicone rubber lip seal which forms a flap seal against a tapered spigot feature built into the wall. The novelty of this filter design is that the bag is an integral part of the filter and is attached onto the filter flange. This enables the inside of the filter, where the contamination particulate has collected, to be sealed/bagged off and hence the dust burden retained

  1. Magnetic flux tube tunneling

    International Nuclear Information System (INIS)

    We present numerical simulations of the collision and subsequent interaction of orthogonal magnetic flux tubes. The simulations were carried out using a parallelized spectral algorithm for compressible magnetohydrodynamics. It is found that, under a wide range of conditions, the flux tubes can open-quotes tunnelclose quotes through each other, a behavior not previously seen in studies of either vortex tube or magnetic flux tube interactions. Two conditions must be satisfied for tunneling to occur: the magnetic field must be highly twisted with a field line pitch >1, and the Lundquist number must be somewhat large, ≥2880. An examination of magnetic field lines suggests that tunneling is due to a double-reconnection mechanism. Initially orthogonal field lines reconnect at two specific locations, exchange interacting sections, and open-quotes passclose quotes through each other. The implications of these results for solar and space plasmas are discussed. copyright 1997 The American Physical Society

  2. Integrated structure vacuum tube

    Science.gov (United States)

    Dimeff, J.; Kerwin, W. J. (Inventor)

    1976-01-01

    High efficiency, multi-dimensional thin film vacuum tubes suitable for use in high temperature, high radiation environments are described. The tubes are fabricated by placing thin film electrode members in selected arrays on facing interior wall surfaces of an alumina substrate envelope. Cathode members are formed using thin films of triple carbonate. The photoresist used in photolithography aids in activation of the cathodes by carbonizing and reacting with the reduced carbonates when heated in vacuum during forming. The finely powdered triple carbonate is mixed with the photoresist used to delineate the cathode locations in the conventional solid state photolithographic manner. Anode and grid members are formed using thin films of refractory metal. Electron flow in the tubes is between grid elements from cathode to anode as in a conventional three-dimensional tube.

  3. Neural Tube Defects

    OpenAIRE

    Greene, Nicholas D. E.; Copp, Andrew J.

    2014-01-01

    Neural tube defects (NTDs), including spina bifida and anencephaly, are severe birth defects of the central nervous system that originate during embryonic development when the neural tube fails to close completely. Human NTDs are multifactorial, with contributions from both genetic and environmental factors. The genetic basis is not yet well understood, but several nongenetic risk factors have been identified as have possibilities for prevention by maternal folic acid supplementation. Mechani...

  4. Power vacuum tubes handbook

    CERN Document Server

    Whitaker, Jerry

    2012-01-01

    Providing examples of applications, Power Vacuum Tubes Handbook, Third Edition examines the underlying technology of each type of power vacuum tube device in common use today. The author presents basic principles, reports on new development efforts, and discusses implementation and maintenance considerations. Supporting mathematical equations and extensive technical illustrations and schematic diagrams help readers understand the material. Translate Principles into Specific Applications This one-stop reference is a hands-on guide for engineering personnel involved in the design, specification,

  5. Aeronautical tubes and pipes

    Science.gov (United States)

    Beauclair, N.

    1984-12-01

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

  6. DRA-8. Friction reduction in corrugated tubes

    Energy Technology Data Exchange (ETDEWEB)

    Bjurstroem, H.; Nilsson, Jarl [AaF Energikonsult Stockholm AB (Sweden)

    1996-06-01

    The effect of wall roughness on friction reduction with micellar additives has been studied using Habon-G or Dobon-G as additive and three corrugated pipes as model rough-walled pipes. The k{sub s}/D ratios that could be calculated for these three tubes are 0.04, 0.01 and 0.008 respectively. A fourth sample of rough-walled pipe was provided by a naturally rough pipe: k{sub s}/D=8{center_dot}10{sup -4}. Within the range of flow rates attainable in the test loop, flow is fully rough in the narrowest corrugated pipe (k{sub s}/D=0.04). Flow in the other two corrugated pipes and in the naturally rough tube is transitionally rough. Wall roughness deteriorates friction reduction in the narrowest corrugated tube and in the naturally rough tube. The lowering of pressure drop and mean wall shear stress is reduced, from 82 percent in a smooth tube to 70 percent in the naturally rough tube and 60 percent in the corrugated tube. The upper temperature limit for friction reduction is a few degrees lower than for a smooth pipe. However, the maximum mean wall shear stress that can be withstood by the friction reducing solution increases. It is almost doubled in the case of the corrugated pipe. In the other two corrugated pipes, neither the extent of friction reduction nor the critical mean wall shear stresses are affected. It seems thus that, as far as regular roughness patterns are concerned, they do not influence friction reduction in the transitionally rough regime. 32 refs, 20 figs, 10 tabs

  7. An investigation of wall thinning and cross sectional geometry change of bent tube of small diameters

    Energy Technology Data Exchange (ETDEWEB)

    Van, Nguyen Dang; Ihn, Namgung [KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)

    2014-10-15

    The ununiformed deformation of cross section of bent tube also occurs, which is not perfectly circular and uniform but a significant ovality can result in from the fabrication process. In this study, an investigation of the deformation profile of bent tube such as wall thickening/thinning and cross-sectional distortion in cold bending process will be performed. The finite element model, using ANSYS 14.5, is developed and simulated the bending process. The results will be investigated for any change of diameter and circularity perpendicular to the bending axis. The analyses showed that the change of wall thickness of tube will happen in bending process. Consequently, the bend region of tube appears thicker wall at intrados and thinner wall at extrados. Moreover, bending process affects the ovality of tube cross section at bend region. From these results, wall thinning and cross-sectional ovality change need to be considered in the application and design of tube. In case of ICI guide tube, the inner circularity very important since ICI probe has to pass through the bend elbow, and any deviation from the tolerance causes stuck of ICI probe in the bend region. This is one of the particular applications where geometric deviations need to be carefully monitored. In fluid application of tube, the thinning is more of concern than the ovality of cross section. Hence there is also limit on how much wall thinning be allowed. The simulation presented in this paper is focused on the estimation of geometric variation resulted in bending process of tube with typical bending process.

  8. AC losses in circular arrangements of parallel superconducting tapes

    DEFF Research Database (Denmark)

    Kühle (fratrådt), Anders Van Der Aa; Træholt, Chresten; Däumling, Manfred; Olsen, Søren Krüger; Tønnesen, Ole

    The DC and AC properties of superconducting tapes connected in parellel and arranged in a single closed layer on two tubes (correspondig to power cable models with infinite pitch) with different diameters are compared. We find that the DC properties, i.e. the critical currents of the two arrangem......The DC and AC properties of superconducting tapes connected in parellel and arranged in a single closed layer on two tubes (correspondig to power cable models with infinite pitch) with different diameters are compared. We find that the DC properties, i.e. the critical currents of the two...... arrangements, scale with the number of tapes and hence appear to be independent of the diameter.However, the AC loss per tape (for a given current per tape) appears to decrease with increasing diameter of the circular arrangement. Compared to a model for the AC loss in a continuous superconducting layer...... (Monoblock model) the measured values are about half an order of magnitude higher than expected for the small diameter arrangement. When compared to the AC loss calculated for N individual superconducting tapes using a well known model ( Norris elliptical) the difference is slightly smaller....

  9. AC losses in circular arrangements of parallel superconducting tapes

    DEFF Research Database (Denmark)

    Kühle (fratrådt), Anders Van Der Aa; Træholt, Chresten; Däumling, Manfred;

    1998-01-01

    The DC and AC properties of superconducting tapes connected in parellel and arranged in a single closed layer on two tubes (correspondig to power cable models with infinite pitch) with different diameters are compared. We find that the DC properties, i.e. the critical currents of the two arrangem......The DC and AC properties of superconducting tapes connected in parellel and arranged in a single closed layer on two tubes (correspondig to power cable models with infinite pitch) with different diameters are compared. We find that the DC properties, i.e. the critical currents of the two...... arrangements, scale with the number of tapes and hence appear to be independent of the diameter.However, the AC loss per tape (for a given current per tape) appears to decrease with increasing diameter of the circular arrangement. Compared to a model for the AC loss in a continuous superconducting layer...... (Monoblock model) the measured values are about half an order of magnitude higher than expected for the small diameter arrangement. When compared to the AC loss calculated for N individual superconducting tapes using a well known model ( Norris elliptical) the difference is slightly smaller....

  10. Steam generator tube fretting - Darlington NGS experience

    International Nuclear Information System (INIS)

    Early signs of tube fretting in the U-bend region of Darlington NGS Steam Generators (SGs) were observed during the metallurgical examination of the removed peripheral tube U-bend sections from Unit 4 SG3 in 1995. During a forced outage in early 1998, Eddy Current (ECT) tube inspections in Unit 2 SG4 revealed more extensive fretting of the tubes at the U-bend AVB support locations. Subsequently in the period of 1999-2001, planned Eddy Current tube inspections have been carried out in all units covering all SGs. These inspections have revealed considerable U-bend tube fretting with a number of these fret depths in excess of 40% tw. Evaluation of the ECT and UT results, in conjunction with engineering assessment of the SG design and construction, have determined tube fretting in the U-bend region as an active and reportable degradation mechanism in these SGs. To date, all 16 Darlington SGs have undergone a major ECT inspection. In these inspections as a minimum, the identified fretting region of the U-bend has been adequately covered. Analyses of the inspection results have been carried out to provide trends and observations of the fretting in the U-bend. These showed the fretted U-bend tubes to be localized in the area bounded by Rows 70 and above, and Columns 39 to 83 which has been defined as the 'Area at Risk' of U-bend fretting for Darlington SGs. In the distribution of the frets at the U-bend support locations, they showed a strong biasing of the fretting towards the cold leg supports with the mean centered a third the way between CU4 and CU3. A general understanding of the 'Root Cause of Fretting' shows it to be associated with tube clearance, which invariably results and acts together with conditions of insufficient support preload. While the fretting by tube tends to exhibit a certain degree of randomness, the fretting remains localized to the 'Area at Risk'. This offers a unique opportunity of localized corrective measures that are both simpler in design

  11. Breaking the fault tree circular logic

    International Nuclear Information System (INIS)

    Event tree - fault tree approach to model failures of nuclear plants as well as of other complex facilities is noticeably dominant now. This approach implies modeling an object in form of unidirectional logical graph - tree, i.e. graph without circular logic. However, genuine nuclear plants intrinsically demonstrate quite a few logical loops (circular logic), especially where electrical systems are involved. This paper shows the incorrectness of existing practice of circular logic breaking by elimination of part of logical dependencies and puts forward a formal algorithm, which enables the analyst to correctly model the failure of complex object, which involves logical dependencies between system and components, in form of fault tree. (author)

  12. Entanglement of quantum circular states of light

    Science.gov (United States)

    Horoshko, D. B.; De Bièvre, S.; Kolobov, M. I.; Patera, G.

    2016-06-01

    We present a general approach to calculating the entanglement of formation for superpositions of two-mode coherent states, placed equidistantly on a circle in phase space. We show that in the particular case of rotationally invariant circular states the Schmidt decomposition of two modes, and therefore the value of their entanglement, are given by analytical expressions. We analyze the dependence of the entanglement on the radius of the circle and number of components in the superposition. We also show that the set of rotationally invariant circular states creates an orthonormal basis in the state space of the harmonic oscillator, and this basis is advantageous for representation of other circular states of light.

  13. Symmetric Circular Matchings and RNA Folding

    DEFF Research Database (Denmark)

    Hofacker, Ivo L.; Reidys, Christian; Stadler, Peter F.

    2012-01-01

    RNA secondary structures can be computed as optimal solutions of certain circular matching problems. An accurate treatment of this energy minimization problem has to account for the small --- but non-negligible --- entropic destabilization of secondary structures with non-trivial automorphisms....... Such intrinsic symmetries are typically excluded from algorithmic approaches, however, because the effects are small, they play a role only for RNAs with symmetries at sequence level, and they appear only in particular settings that are less frequently used in practical application, such as circular...... asymptotic results for both the circular and the co-folding version are derived....

  14. Circular polarization memory in polydisperse scattering media

    CERN Document Server

    Macdonald, Callum M; Meglinski, Igor

    2015-01-01

    We investigate the survival of circularly polarized light in random scattering media. The surprising persistence of this form of polarization has a known dependence on the size and refractive index of scattering particles, however a general description regarding polydisperse media is lacking. Through analysis of Mie theory, we present a means of calculating the magnitude of circular polarization memory in complex media, with total generality in the distribution of particle sizes and refractive indices. Quantification of this memory effect enables an alternate pathway towards recovering particle size distribution, based on measurements of diffusing circularly polarized light.

  15. Tube of (Circle F, D0, D2) Bound State in Melvin Background

    OpenAIRE

    Huang, Wung-Hong

    2004-01-01

    By using the Born-Infeld action we show that the $m$ circular fundamental strings, $n$ D2-branes and $k$ D0-branes could become a tubular bound state which is prevented from collapsing by the magnetic force in the Melvin background. However, if the ratio $m/n$ is larger then a critical value the tube will become unstable and collapse to zero radius. We make analyses to find the critical value and tube radius therein. The tube configurations we found are different from the well known tubular b...

  16. Geiger-Muller tubes

    International Nuclear Information System (INIS)

    A Geiger-Muller tube designed for use in an environment (for example, mounted on a rock drill) where subjected to mechanical shock and vibration has a tensioned anode wire secured by welding to securement members between first and second mounts at opposite ends of the tube envelope. The wire tension is adjusted to a high value with a screwable-adjustment means which is locked eg. by a spot-weld or by a locking nut, in the adjusted position, so that the natural frequency of the vibration of the tensioned wire does not resonate with (and may be much higher than) the frequencies to which the tube is subjected in use. The wire frequency is typically in excess of 400Hz and even 500Hz. The adjustment means may be included in the mount via which the envelope is evacuated and back-filled with the ionizible gas, and a gas-tight seal can be provided around this part of the mount, for example by sealing off the gas pump tube. However the adjustment means may be designed into another part of the tube, for example using telescopic parts of the envelope whose sliding junction is made gas tight with a flexible seal. (author)

  17. Categorising YouTube

    Directory of Open Access Journals (Sweden)

    Thomas Mosebo Simonsen

    2011-09-01

    Full Text Available This article provides a genre analytical approach to creating a typology of the User Generated Content (UGC of YouTube. The article investigates the construction of navigationprocesses on the YouTube website. It suggests a pragmatic genre approach that is expanded through a focus on YouTube’s technological affordances. Through an analysis of the different pragmatic contexts of YouTube, it is argued that a taxonomic understanding of YouTube must be analysed in regards to the vacillation of a user-driven bottom-up folksonomy and a hierarchical browsing system that emphasises a culture of competition and which favours the already popular content of YouTube. With this taxonomic approach, the UGC videos are registered and analysed in terms of empirically based observations. The article identifies various UGC categories and their principal characteristics. Furthermore, general tendencies of the UGC within the interacting relationship of new and old genres are discussed. It is argued that the utility of a conventional categorical system is primarily of analytical and theoretical interest rather than as a practical instrument.

  18. 77 FR 42077 - Environmental Justice: Final Circular

    Science.gov (United States)

    2012-07-17

    ... social service providers to identify transportation challenges and mitigation strategies. FTA is... Register notice (76 FR 60590). II. Chapter-by-Chapter Analysis A. General Comments This section addresses... Circular does not contain any new responsibilities for recipients. Recipients' responsibilities...

  19. Dual frequency launcher for circularly polarized antenna

    Science.gov (United States)

    Chen, Ming H.

    1989-10-01

    A dual frequency antenna feed is formed from a central, circular waveguide connected to the flat boundry of circular, disk-shaped resonant cavity. A second circular waveguide is connected one end of a disk-shaped resonant cavity. Energy of one frequency enters and exits the cavity along the common axis of the waveguides. Energy of the second frequency is introduced to the same resonant cavity by way of a plurality of bandpass filters, also connected to the cavity. This energy enters by way of slots in the cylindrical walls of the cavity. The central circular waveguide is propagating at one frequency but cut off at the second frequency. These bandpass filters are at this pass band for the second frequency, but at the rejection band for the first frequency. Therefore, the isolation between these two input ports are obtained.

  20. Unleashing the Power of the Circular Economy

    Energy Technology Data Exchange (ETDEWEB)

    Kok, L.; Wurpel, G.; Ten Wolde, A. [IMSA Amsterdam, Amsterdam (Netherlands)

    2013-04-15

    The concept of circular economy is an economic and industrial system that focuses on the reusability of products and raw materials, reduces value destruction in the overall system and aims at value creation within each tier of the system. This report for Circle Economy (CE) outlines the general direction and concrete steps that must be taken to accomplish a breakthrough to a circular economy. It also provides a knowledge base behind the concept, connecting it to sustainability.

  1. Construction of Circular Economy Industrial System

    Institute of Scientific and Technical Information of China (English)

    Cao Man; Ye Wenhu

    2007-01-01

    It is difficult to realize the transformation from traditional economy industrial system to circular economy industrial system.Regarding primary raw materials as the indicators,the industrial system has been specified according to the divergence among the indicators and the circular utilization modes.In comparison with the association among industrial systems,the relationship among industrial sub-systems is named as industrial cross-linking in this paper.The industrial system which could completely utilize and recycle the indicators should be increased and strengthened,and the circular economy industrial system with complete industrial association and industrial cross-linking should also be constructed.Taking the development of circular agricultural system basing on the traditional agricultural system as an example,the traditional agricultural products are regarded as the indicators which have been divided into foodstuff and crop straws which are used to produce food and articlesfor use,like fertilizer,energy and papers etc.The way to construct the circular agricultural industrial system is to increase the industrial systems that could utilize the products generated from crop straws,feces and other castoffs and transform the wastewater and other trucks into environmental friendly products.It has also been pointed out that the construction of circular economy industrial system is conducive to the foundation of circular industrial economics and the establishment of the construction layout of circular economy and the application schemes.Suggestions to the theoretical and practical work of the next step have also been brought forward in this paper.

  2. A Conceptual Framework for Circular Design

    Directory of Open Access Journals (Sweden)

    Mariale Moreno

    2016-09-01

    Full Text Available Design has been recognised in the literature as a catalyst to move away from the traditional model of take-make-dispose to achieve a more restorative, regenerative and circular economy. As such, for a circular economy to thrive, products need to be designed for closed loops, as well as be adapted to generate revenues. This should not only be at the point of purchase, but also during use, and be supported by low-cost return chains and reprocessing structures, as well as effective policy and regulation. To date, most academic and grey literature on the circular economy has focused primarily on the development of new business models, with some of the latter studies addressing design strategies for a circular economy, specifically in the area of resource cycles and design for product life extension. However, these studies primarily consider a limited spectrum of the technical and biological cycles where materials are recovered and restored and nutrients (e.g., materials, energy, water are regenerated. This provides little guidance or clarity for designers wishing to design for new circular business models in practice. As such, this paper aims to address this gap by systematically analysing previous literature on Design for Sustainability (DfX (e.g., design for resource conservation, design for slowing resource loops and whole systems design and links these approaches to the current literature on circular business models. A conceptual framework is developed for circular economy design strategies. From this conceptual framework, recommendations are made to enable designers to fully consider the holistic implications for design within a circular economy.

  3. Dual-band Omnidirectional Circularly Polarized Antenna

    OpenAIRE

    Narbudowicz, Adam; Bao, Xiulong; Ammann, Max

    2013-01-01

    A dual-band omnidirectional circularly polarized antenna is proposed. The antenna comprises back-to-back microstrip patches fed by a coplanar waveguide. A very low frequency ratio of 1.182 has been achieved, which can be easily tuned by adjusting four lumped capacitors incorporated into the antenna. An analysis of the omnidirectional circular polarization mechanism as well the dual band operation is provided and confirmed by numerical and experimental data. Key parameters to tune the resonant...

  4. Single particle dynamics in circular accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Ruth, R.D.

    1986-10-01

    The purpose of this paper is to introduce the reader to the theory associated with the transverse dynamics of single particle, in circular accelerators. The discussion begins with a review of Hamiltonian dynamics and canonical transformations. The case of a single particle in a circular accelerator is considered with a discussion of non-linear terms and chromaticity. The canonical perturbation theory is presented and nonlinear resonances are considered. Finally, the concept of renormalization and residue criterion are examined. (FI)

  5. On the circular polarization of pulsar radiation

    OpenAIRE

    Lyubarskii, Y. E.; Petrova, S. A.

    1999-01-01

    We consider the polarization behaviour of radio waves propagating through an ultrarelativistic highly magnetized electron-positron plasma in a pulsar magnetosphere. The rotation of magnetosphere gives rise to the wave mode coupling in the polarization-limiting region. The process is shown to cause considerable circular polarization in the linearly polarized normal waves. Thus, the circular polarization observed for a number of pulsars, despite the linear polarization of the emitted normal wav...

  6. Kajian Efektifitas Sistem Struktur Tube Dengan Sistem Struktur Tube In Tube Di Bawah Beban Gempa

    OpenAIRE

    Sihotang, Dian Frisca

    2010-01-01

    Berkembangnya teknologi telah melahirkan berbagai sistem struktur bangunan tahan gempa, seperti penggunaan sistem tube.Tube adalah merupakan frame penahan gaya yang menahan gaya gaya lateral dengan struktur kantilever kotak yang memiliki jarak kolom yang berdekatan yang dipasang pada sekeliling gedung, sehingga penampilan wajah depan gedung seperti lubang jendela jendela yang terbuka. Rancangan tube ini kemudian dimodifikasi lagi dengan menambah pengaku pada bagian dalam ( konsep tube in tube...

  7. Angle-resolved x-ray circular and magnetic circular dichroisms: Definitions and applications

    OpenAIRE

    Tong, DSY; X Guo; Tobin, JG; Waddill, GD

    1996-01-01

    We introduce definitions of angle-resolved x-ray circular dichroism (ARXCD) and magnetic x-ray circular dichroism (ARMXCD). As defined, the much larger effect of circular dichroism (ARXCD) is separated from the smaller magnetic (ARMXCD) effect. In all materials, ARXCD is zero along mirror planes while nonzero elsewhere. ARMXCD is nonzero only in magnetic materials. The measurement and analysis of ARMXCD allow element specific surface magnetism and surface structure as well as their inter-rela...

  8. Broadband circularly polarized planar antenna using partially covered circular wide-slot and L-probe

    OpenAIRE

    Fukusako, Takeshi; Sakami, Ryo; Iwata, Kazuki; フクサコ, タケシ; サカミ, リョウ; イワタ, カズキ; 福迫, 武; 酒見, 遼; 岩田, 一樹

    2008-01-01

    The novel structure of a unique circularly polarized broadband antenna that combines an L-shaped probe with a partially covered circular slot has been presented. A principle that can be used to generate CP using the proposed structure has been presented using an L-shaped probe and a modified circular wide slot. Using the above, a 3 -dB AR bandwidth of 58% and matching bandwidth of 57% were obtained at 3.2 GHz.

  9. Neural tube defects

    OpenAIRE

    M.E. Marshall

    1981-01-01

    Neural tube defects refer to any defect in the morphogenesis of the neural tube, the most common types being spina bifida and anencephaly. Spina bifida has been recognised in skeletons found in north-eastern Morocco and estimated to have an age of almost 12 000 years. It was also known to the ancient Greek and Arabian physicians who thought that the bony defect was due to the tumour. The term spina bifida was first used by Professor Nicolai Tulp of Amsterdam in 1652. Many other terms have bee...

  10. Exciton circular dichroism in channelrhodopsin.

    Science.gov (United States)

    Pescitelli, Gennaro; Kato, Hideaki E; Oishi, Satomi; Ito, Jumpei; Maturana, Andrés Daniel; Nureki, Osamu; Woody, Robert W

    2014-10-16

    Channelrhodopsins (ChRs) are of great interest currently because of their important applications in optogenetics, the photostimulation of neurons. The absorption and circular dichroism (CD) spectra of C1C2, a chimera of ChR1 and ChR2 of Chlamydomonas reinhardtii, have been studied experimentally and theoretically. The visible absorption spectrum of C1C2 shows vibronic fine structure in the 470 nm band, consistent with the relatively nonpolar binding site. The CD spectrum has a negative band at 492 nm (Δε(max) = -6.17 M(-1) cm(-1)) and a positive band at 434 nm (Δε(max) = +6.65 M(-1) cm(-1)), indicating exciton coupling within the C1C2 dimer. Time-dependent density functional theory (TDDFT) calculations are reported for three models of the C1C2 chromophore: (1) the isolated protonated retinal Schiff base (retPSB); (2) an ion pair, including the retPSB chromophore, two carboxylate side chains (Asp 292, Glu 162), modeled by acetate, and a water molecule; and (3) a hybrid quantum mechanical/molecular mechanical (QM/MM) model depicting the binding pocket, in which the QM part consists of the same ion pair as that in (2) and the MM part consists of the protein residues surrounding the ion pair within 10 Å. For each of these models, the CD of both the monomer and the dimer was calculated with TDDFT. For the dimer, DeVoe polarizability theory and exciton calculations were also performed. The exciton calculations were supplemented by calculations of the coupling of the retinal transition with aromatic and peptide group transitions. For the dimer, all three methods and three models give a long-wavelength C2-axis-polarized band, negative in CD, and a short-wavelength band polarized perpendicular to the C2 axis with positive CD, differing in wavelength by 1-5 nm. Only the retPSB model gives an exciton couplet that agrees qualitatively with experiment. The other two models give a predominantly or solely positive band. We further analyze an N-terminal truncated mutant

  11. PLANAR MOTION OF A SLIGHTLY DISTORTED CIRCULAR CYLINDER AROUND ANOTHER CIRCULAR ONE

    Institute of Scientific and Technical Information of China (English)

    SUN Ren; CHWANG Allen T.

    2004-01-01

    Accurate prediction of the motion of a body moving around another one in an unbounded fluid and determi-nation of the hydrodynamic interaction between them are im-portant in the coastal and offshore engineering. For two-dimensional cases, most of the previous studies were focused on the interaction between circular cylinders without considering the non-circular situation. To break through the limitation of"circular" bodies, in the present paper the boundary perturbation method was employed to investigate the motion of a slightly distorted circular cylinder around a circular one. An approximate complex velocity potential in terms of double infinite series expanded at two singular points was derived using the method of continued fractions. The hydrodynamic interaction between two cylinders was computed by solving the dynamical equations of motion. In a relative coordinate system moving with the uniform stream, the kinetic energy of the fluid was expressed as a function of fifteen added masses. Approximate analytical solutions of added masses in the series form were obtained and applied to determine the trajectories of the slightly distorted circular cylinder around a fixed circular one. Numerical results show that the presence of the circular cylinder affects the planar motion of the slightly distorted cirular cylinder and the initial configuration of the slightly distorted circular cylinder has a decisive influence on the development of its rotational motion.

  12. Development of a shock tube for nondestructive evaluation in concrete structures

    International Nuclear Information System (INIS)

    This paper is concerned with the development of a shock tube suited for nondestructive evaluation in concrete structures. For this purpose, a shock wave is developed from the reaction of propane-air mixtures in a long circular cylindrical tube. The propane and air mixture is injected into reaction chamber from a mixing chamber. Ignited the mixture, a detonation wave goes through into the atmosphere from the open end of the shock tube. The performance of the tube was evaluated by measuring the pressure distribution on specimen surface and experiments of defect detection for a concrete specimen. In the pressure measurement, triangular wave with a pressure of 4 kPa and duration of 0.4 ms was obtained at 500 mm distance from the shock tube. In the defect detection, we could detect a defect with a diameter of 200 mm and a depth of 50 mm clearly. (orig.)

  13. Hough transform method for track finding in center drift chamber

    Science.gov (United States)

    Azmi, K. A. Mohammad Kamal; Wan Abdullah, W. A. T.; Ibrahim, Zainol Abidin

    2016-01-01

    Hough transform is a global tracking method used which had been expected to be faster approach for tracking the circular pattern of electron moving in Center Drift Chamber (CDC), by transforming the point of hit into a circular curve. This paper present the implementation of hough transform method for the reconstruction of tracks in Center Drift Chamber (CDC) which have been generated by random number in C language programming. Result from implementation of this method shows higher peak of circle parameter value (xc,yc,rc) that indicate the similarity value of the parameter needed for circular track in CDC for charged particles in the region of CDC.

  14. Hough transform method for track finding in center drift chamber

    Energy Technology Data Exchange (ETDEWEB)

    Azmi, K. A. Mohammad Kamal, E-mail: khasmidatul@siswa.um.edu.my; Wan Abdullah, W. A. T., E-mail: wat@um.edu.my; Ibrahim, Zainol Abidin [National Centre for Particle Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2016-01-22

    Hough transform is a global tracking method used which had been expected to be faster approach for tracking the circular pattern of electron moving in Center Drift Chamber (CDC), by transforming the point of hit into a circular curve. This paper present the implementation of hough transform method for the reconstruction of tracks in Center Drift Chamber (CDC) which have been generated by random number in C language programming. Result from implementation of this method shows higher peak of circle parameter value (xc,yc,rc) that indicate the similarity value of the parameter needed for circular track in CDC for charged particles in the region of CDC.

  15. Hough transform method for track finding in center drift chamber

    International Nuclear Information System (INIS)

    Hough transform is a global tracking method used which had been expected to be faster approach for tracking the circular pattern of electron moving in Center Drift Chamber (CDC), by transforming the point of hit into a circular curve. This paper present the implementation of hough transform method for the reconstruction of tracks in Center Drift Chamber (CDC) which have been generated by random number in C language programming. Result from implementation of this method shows higher peak of circle parameter value (xc,yc,rc) that indicate the similarity value of the parameter needed for circular track in CDC for charged particles in the region of CDC

  16. Prawns in Bamboo Tube

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Ingredients: 400 grams Jiwei prawns, 25 grams pork shreds, 5 grams sliced garlic. Condiments: 5 grams cooking oil, minced ginger root and scallions, cooking wine, salt, pepper and MSG (optional) Method: 1. Place the Shelled prawns into a bowl and mix with all the condiments. 2. Stuff the prawns into a fresh bamboo tube,

  17. Thoughts of accelerator tubes

    International Nuclear Information System (INIS)

    A brief, subjective review is given of mechanisms that may be limiting electrostatic accelerator tubes to present levels of performance. Suggestions are made for attacking these limitations with the purpose of stimulating the thinking of designers and users of electrostatic accelerators

  18. Prevalência dos defeitos de fechamento do tubo neural em recém-nascidos do Centro de Atenção à Mulher do Instituto Materno Infantil Prof. Fernando Figueira, IMIP: 2000-2004 Neural tube defects prevalence in newborn infants in the Women Care Center of the Instituto Materno Infantil Prof. Fernando Figueira, IMIP: 2000-2004

    Directory of Open Access Journals (Sweden)

    Sâmya Silva Pacheco

    2006-05-01

    Full Text Available OBJETIVOS: conhecer a prevalência de defeito de fechamento do tubo neural (DFTN em crianças nascidas na maternidade do Centro de Atenção à Mulher do Instituto Materno Infantil Prof. Fernando Figueira (IMIP no período de 2000 a 2004. MÉTODOS: estudo descritivo, do tipo corte transversal, cujos dados foram coletados de um banco de dados do Sistema de Informações sobre Nascidos Vivos do qual foram selecionados todos os registros de recém-nascidos com malformação fetal. A partir daí selecionaram-se os recém-nascidos com DFTN ocorridos no período considerado. RESULTADOS: entre os 24.964 nascimentos, foram registrados 709 recém-nascidos apresentando alguma malformação ao nascer. Ao se considerar apenas os recém nascidos com DFTN, observaram-se 124 registros, representando uma prevalência de 0,5% entre nascimentos naquele período. Os recém-nascidos com DFTN apresentaram características semelhantes aos recém-nascidos com malformações, de uma forma geral. A maioria (68,5% desses recém-nascidos era de parto cesariano e 37,7% apresentaram baixo peso ao nascer. CONCLUSÕES: a prevalência de DFTN entre os nascimentos registrados no Centro de Atenção à Mulher do Instituto Materno Infantil Prof. Fernando Figueira foi elevada (5/1000 nascimentos e isso, provavelmente é reflexo do fato de a maternidade ser referência para gestações de alto-risco.OBJECTIVES: to determine neural tube closing defects in newborns delivered in the maternity ward of the Women Care Center of the Instituto Materno Infantil Prof. Fernando Figueira (IMIP. METHODS: a descriptive cross-sectional cohort study, with data collected from a Born Alive Information System from which all records of newborns with fetal malformation were selected. From these records the ones pertaining to newborns between 2000 and 2004 with the neural tube closing defect were considered. RESULTS: of 24.964 births, 709 newborns with some type of malformation were registered. When

  19. Eccentricity error compensation for geometric camera calibration based on circular features

    International Nuclear Information System (INIS)

    Circular features are very common in geometric camera calibration. The projection of a circular feature is generally a deformed ellipse, not a true ellipse, due to the presence of lens distortion. The center of the deformed ellipse, obtained by fitting the boundary points with an ellipse, does not necessarily coincide with the distorted point corresponding to the center of the undistorted projection of the circular feature. An eccentricity error will be introduced if the two points are considered to be coincident. In this study three main factors that affect the amount of the eccentricity error are discussed, including the form and amount of lens distortion, the size of the circular feature and the tilt of the supporting plane. Then, an effective geometric camera calibration method is proposed where the eccentricity error is compensated by establishing the correspondence between the estimated model position and the real position of the fitted center of the deformed ellipse. Both simulation and measurement data verify the existence of the eccentricity error and the effectiveness of the proposed method. (paper)

  20. OPERATIONAL CIRCULAR NO 6 - JUNE 2001 'CERN SCIENTIFIC DOCUMENTS'

    CERN Multimedia

    Human Resources Division

    2001-01-01

    This new operational circular has been drawn up. It cancels and replaces Administrative Circular N° 29 entitled "Principles and procedures governing CERN publications and reports and other publications arising from CERN work". Copies are available from Divisional Secretariats. Note : Administrative and operational circulars, as well as the lists of those in force, are available for consultation on WWW : ADMINISTRATIVE CIRCULARSOPERATIONAL CIRCULARS

  1. Sedimentation of an oblate ellipsoid in narrow tubes

    Science.gov (United States)

    Yang, Xin; Huang, Haibo; Lu, Xiyun

    2015-12-01

    Sedimentation behaviors of an oblate ellipsoidal particle inside narrow [R /a ∈(1.2 ,2.0 )] infinitely long circular tubes are studied by the lattice Boltzmann method, where R and a are the radius of the tube and the length of the semimajor axis of the ellipsoid, respectively. The Archimedes numbers (Ar) up to 70 are considered. Four periodic and two steady sedimentation modes are identified. It is the first time that the anomalous mode has been found in a circular tube for an ellipsoidal particle. The phase diagram of the modes as a function of Ar and R /a is obtained. The anomalous mode is observed in the larger R /a and lower-Ar regime. Through comparisons between the anomalous and oscillatory modes, it is found that R/a plays a critical role for the anomalous mode. Some constrained cases with two steady modes are simulated. It is found that the particle settles faster in the unconstrained modes than in the corresponding constrained modes. This might inspire further study on why the particle adopts a specific mode under a certain circumstance.

  2. Condensation Analysis of Steam/Air Mixtures in Horizontal Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kwon Yeong; Bae, Sung Won [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Moo Hwan [Pohang University of Science and Technology, Pohang (Korea, Republic of)

    2008-05-15

    Perhaps the most common flow configuration in which a convective condensation occurs is a flow in a horizontal circular tube. This configuration is encountered in air-conditioning and refrigeration condensers as well as condensers in Rankine power cycles. Although a convective condensation is also sometimes contrived to occur in a co-current vertical downward flow, a horizontal flow is often preferred because the flow can be repeatedly passed through the heat exchanger core in a serpentine fashion without trapping liquid or vapor in the return bends. Many researchers have investigated a in-tube condensation for horizontal heat exchangers. However, almost all of them obtained tube section-averaged data without a noncondensable gas. Recently, Wu and Vierow have experimentally studied the condensation of steam in a horizontal heat exchanger with air present. In order to measure the condenser tube inner surface temperatures and to calculate the local heat fluxes, they developed an innovative thermocouple design that allowed for nonintrusive measurements. Here we developed a theoretical model using the heat and mass analogy to analyze a steam condensation with a noncondensable gas in horizontal tubes.

  3. Steam generator tube laser sleeving

    International Nuclear Information System (INIS)

    For many years, Framatome has been used with different techniques and means to perform the steam generator tube sleeving operation, such as the 'mechanical' either GTAW welded or kinetic welding process. As soon as first power laser units appeared on the market we felt right interested in applying this process to the sleeving operation. After comparison between all the processes and equipments existing at that time (that is to say CO2 and YAG laser units), we chose the YAG and bought a 1.2 kW NEC laser unit in 1988. As it was installed in our Welding Center of Le Creusot, this equipment enabled us carrying out a preliminary test programme which targets were: getting the mastery of the equipment and associated technologies, implementing this process for the sleeve welding operation by improvement of the welding-pen. The NEC laser unit became afterwards transferred to our workshop in Chalon-sur-Saone (June 1990), where we achieved the final tests of the process at the same time we were investigating the development of industrial operation means. The actual program is mainly focused on 7/8'' tube steam generator repair process at tubesheet outlet. Yet made sure that our methods and means apply as well to 3/4'' tubes up to second tube support-plate level. Sleeves are made of heat-treated Inconel 690. The sleeved unit has been designed to provide the same breaking strength and leak-tightness as the tube. The upper part of sleeve consists of an anti-pop out length which ensures some locking-up in case the tube breaks in upper transition expansion area. Preliminary tests dealt with the various parameters which may exert an influence on geometry and quality of the, weld bead, as: - laser beam power (for continuous and pulsed modes), - welding speed, - focal spot size and location from the surface to be welded, - protective gas. After performance of preliminary tests on many thousands of weld beads we decided to use the process according to following criteria: Weld quality

  4. Flow Characteristics of a Liquid Crystal Mixture in a Circular Pipe Electrode

    Science.gov (United States)

    Tsukiji, Tetsuhiro; Koyabu, Eitaro

    A circular pipe electrode was developed to control the pressure and the flow rate of the ER(Electro-rheological) fluids by one of the authors. The shape of the electrode is a circular pipe and some parts of the inner surface of the pipe are the electrode. The diameter of the tube is 1mm and the four pairs of the electrode are used. In the present study a liquid crystal mixture is selected for a homogeneous ER fluid and the pressure drop of the circular pipe electrode is measured for the constant flow rates under application of the voltages. The voltages are added in the peripheral direction. The director which is the average direction of the molecular of the liquid crystal is perpendicular to the flow direction. On the other hands, numerical analysis of the electric fields and the flow in the circular pipe electrode is conducted and the relations between the flow rate and the pressure are obtained for various electric field intensities, which almost agree with experimental results. The emphasized point of the present flow analysis is assuming that the viscosity of a liquid crystal mixture distributes in the flow field. Furthermore the pulse-wave voltages are added to the electrodes to control the pressure drop using the pulse width modulation. It is found that the pressure can be controlled using the pulse width modulation in the some range of the parameters.

  5. Researches on Relationship between Circular Agriculture and Industrial Diversity

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    First, this paper establishes the conceptual model of circular agriculture, conducts systematic analysis on the circular agriculture on the basis of conceptual model, and discusses the characteristics of closeness and openness of circular agriculture and relationship between closeness and openness of circular agriculture. Second, this paper introduces the industrial diversity related to circular agriculture, defines the concept of industry and the concept of industries related to agriculture, and illustrates the related industries that are conducive to circular agriculture and the related industries that are not conducive to circular agriculture. Finally, this paper analyzes the mutual relationship between circular agriculture and industrial diversity as follows: in the system of circular agriculture, the industrial diversity can transform the wastes in upstream industries into resources in downstream industries; the industrial diversity creates possibility for recycling of agricultural byproducts; the industrial diversity is conducive to the diversification of industries related to circular agriculture.

  6. American Geriatrics Society feeding tubes in advanced dementia position statement.

    Science.gov (United States)

    2014-08-01

    When eating difficulties arise, feeding tubes are not recommended for older adults with advanced dementia. Careful hand feeding should be offered because hand feeding has been shown to be as good as tube feeding for the outcomes of death, aspiration pneumonia, functional status, and comfort. Moreover, tube feeding is associated with agitation, greater use of physical and chemical restraints, healthcare use due to tube-related complications, and development of new pressure ulcers. Efforts to enhance oral feeding by altering the environment and creating patient-centered approaches to feeding should be part of usual care for older adults with advanced dementia. Tube feeding is a medical therapy that an individual's surrogate decision-maker can decline or accept in accordance with advance directives, previously stated wishes, or what it is thought the individual would want. It is the responsibility of all members of the healthcare team caring for residents in long-term care settings to understand any previously expressed wishes of the individuals (through review of advance directives and with surrogate caregivers) regarding tube feeding and to incorporate these wishes into the care plan. Institutions such as hospitals, nursing homes, and other care settings should promote choice, endorse shared and informed decision-making, and honor preferences regarding tube feeding. They should not impose obligations or exert pressure on individuals or providers to institute tube feeding. PMID:25039796

  7. Total and Differential Efficiencies for a Circular Detector Viewing a Circular Radiator of Finite Thickness

    International Nuclear Information System (INIS)

    Total and differential detection efficiencies have been computed for a circular detector viewing a circular radiator of finite thickness. Isotropic, cosines and n-p scattering angular emission distributions of the radiated particles are considered. Tables are given for the total efficiencies as well as for the differential efficiencies in the n-p scattering case

  8. Quarter-wave pulse tube

    Science.gov (United States)

    Swift, G. W.; Gardner, D. L.; Backhaus, S. N.

    2011-10-01

    In high-power pulse-tube refrigerators, the pulse tube itself can be very long without too much dissipation of acoustic power on its walls. The pressure amplitude, the volume-flow-rate amplitude, and the time phase between them evolve significantly along a pulse tube that is about a quarter-wavelength long. Proper choice of length and area makes the oscillations at the ambient end of the long pulse tube optimal for driving a second, smaller pulse-tube refrigerator, thereby utilizing the acoustic power that would typically have been dissipated in the first pulse-tube refrigerator's orifice. Experiments show that little heat is carried from the ambient heat exchanger to the cold heat exchanger in such a long pulse tube, even though the oscillations are turbulent and even when the tube is compactly coiled.

  9. Drift tubes of Linac 2

    CERN Multimedia

    Photographic Service

    1977-01-01

    Being redied for installation, those at the right are for tank 1, those on the left for tank 2. Contrary to Linac 1, which had drift-tubes supported on stems, here the tubes are suspended, for better mechanical stability.

  10. Laser welding of a tube

    International Nuclear Information System (INIS)

    For sleeving PWR steam generator tubes, the welding laser work is made under protection of a primary gas going out by the crossing window of the laser and under a secondary gas flowing axially through the head and the tube

  11. Tubing For Sampling Hydrazine Vapor

    Science.gov (United States)

    Travis, Josh; Taffe, Patricia S.; Rose-Pehrsson, Susan L.; Wyatt, Jeffrey R.

    1993-01-01

    Report evaluates flexible tubing used for transporting such hypergolic vapors as those of hydrazines for quantitative analysis. Describes experiments in which variety of tubing materials, chosen for their known compatibility with hydrazine, flexibility, and resistance to heat.

  12. A broadband, circular-polarization selective surface

    Science.gov (United States)

    Momeni Hasan Abadi, Seyed Mohamad Amin; Behdad, Nader

    2016-06-01

    We introduce a new technique for designing wideband circular-polarization selective surfaces (CPSSs) based on anisotropic miniaturized element frequency selective surfaces. The proposed structure is a combination of two linear-to-circular polarization converters sandwiching a linear polarizer. This CPSS consists of a number of metallic layers separated from each other by thin dielectric substrates. The metallic layers are in the form of two-dimensional arrays of subwavelength capacitive patches and inductive wire grids with asymmetric dimensions and a wire grid polarizer with sub-wavelength period. The proposed device is designed to offer a wideband circular-polarization selection capability allowing waves with left-hand circular polarization to pass through while rejecting those having right-hand circular polarization. A synthesis procedure is developed that can be used to design the proposed CPSS based on its desired band of operation. Using this procedure, a prototype of the proposed CPSS operating in the 12-18 GHz is designed. Full-wave electromagnetic simulations are used to predict the response of this structure. These simulation results confirm the validity of the proposed design concept and synthesis procedure and show that proposed CPSS operates within a fractional bandwidth of 40% with a co-polarization transmission discrimination of more than 15 dB. Furthermore, the proposed design is shown to be capable of providing an extremely wide field of view of ±60°.

  13. Environmental issues elimination through circular economy

    Science.gov (United States)

    Špirková, M.; Pokorná, E.; Šujanová, J.; Samáková, J.

    2016-04-01

    Environmental efforts of European Union are currently going towards circular economy. Tools like Extended Producer Responsibility and Eco-design were established. The circular economy deals with resources availability issue on one hand and waste management on the other hand. There are few pioneering companies all over the world with some kind of circular economy practice. Generally the concept is not very wide-spread. The paper aims to evaluate possibility of transition towards circular economy in Slovak industrial companies. They need to have an active approach to material treatment of their products after usage stage. Innovation is another important pre-condition for the transition. Main problem of current cradle to grave system is landfilling of valuable materials after one cycle of usage. Their potential value for next manufacturing cycles is lost. Companies may do not see connection between waste management and material resource prices and volatility of supplies. Municipalities are responsible for municipal waste collection and treatment in Slovakia. The circular economy operates by cradle to cradle principle. Company manages material flow until the material comes back to the beginning of manufacturing process by itself or by another partners. Stable material supplies with quite low costs are provided this way. It is necessary to deal with environmental problems in phase of product design. Questionnaire survey results show on one hand low involvement of industrial companies in waste management area, however on the other hand they are open to environmental innovations in future.

  14. A COMPACT CIRCULARLY POLARIZED SLOTTED MICROSTRIP ANTENNA

    Directory of Open Access Journals (Sweden)

    V. Jebaraj

    2014-12-01

    Full Text Available Slot antennas are often used at UHF and microwave frequencies. In slot antenna for RFID reader applications the frequency ranges from 902-923MHz to achieve circular polarization. The shapes and size of the slot, as well as the driving frequency, determine the radiation distribution pattern. The proposed compact size circularly polarized slotted microstrip antenna are summarized with design rules. The circularly polarized radiation in square patch antenna can be obtained by perturbation technique with different shapes of slot in the orthogonal direction. A single feed configuration based symmetric slotted microstrip antenna is adapted to realize the compact circularly polarized microstrip antennas. Based on the perimeter, the size of the slot on microstrip slot antenna are studied and compared. The Operating frequency of the antenna is 912MHz that can be tuned by varying the perimeter of the slot while the keeping the circularly polarized radiation unchanged. The schematic and layout are configured by using Advanced Design System (ADS. Return loss, Resonant Frequency, Axial Ratio (AR, and Gain were determined for the proposed system using ADS. A measured 3dB Axial Ratio (AR bandwidth around 6MHz with 16MHz impedance bandwidth has been achieved for the antenna on a RO3004C substrate with dielectric constant 3.38.

  15. Ultrasonic nondestructive tubing inspection system

    International Nuclear Information System (INIS)

    A system for measuring the extent of tube wall erosion in an inspection region of a heat exchanger tube of a nuclear steam generator, uses an ultrasonic means driven helically inside the eroded tube which may be filled with a fluid (e.g., water) to minimize ultrasonic wave attenuation. A control means cooperates with the ultrasonic means to produce a map of the tube wall thickness in an inspection region

  16. Sleeve puller salvages welded tubes

    Science.gov (United States)

    Weaver, J. F.

    1980-01-01

    Tool removes sleeve remnants without distorting or damaging tubes, unlike pliers and other conventional handtools. Tubes can be reused, saving time, labor, and material in many applications. Sleeve-removal fixture consists of pressure screw, swing arm, locking screws, and base. It removes sleeve remnant from tubing after welded joint has been sawed through.

  17. Circularly symmetric light scattering from nanoplasmonic spirals.

    Science.gov (United States)

    Trevino, Jacob; Cao, Hui; Dal Negro, Luca

    2011-05-11

    In this paper, we combine experimental dark-field imaging, scattering, and fluorescence spectroscopy with rigorous electrodynamics calculations in order to investigate light scattering from planar arrays of Au nanoparticles arranged in aperiodic spirals with diffuse, circularly symmetric Fourier space. In particular, by studying the three main types of Vogel's spirals fabricated by electron-beam lithography on quartz substrates, we demonstrate polarization-insensitive planar light diffraction in the visible spectral range. Moreover, by combining dark-field imaging with analytical multiparticle calculations in the framework of the generalized Mie theory, we show that plasmonic spirals support distinctive structural resonances with circular symmetry carrying orbital angular momentum. The engineering of light scattering phenomena in deterministic structures with circular Fourier space provides a novel strategy for the realization of optical devices that fully leverage on enhanced, polarization-insensitive light-matter coupling over planar surfaces, such as thin-film plasmonic solar cells, plasmonic polarization devices, and optical biosensors. PMID:21466155

  18. Analytical Optimization of Piezoelectric Circular Diaphragm Generator

    Directory of Open Access Journals (Sweden)

    S. Mohammadi

    2013-01-01

    Full Text Available This paper presents an analytical study of the piezoelectric circular diaphragm microgenerator using strain energy method. Piezoelectrics are the intelligent materials that can be used as transducer to convert mechanical energy into electrical energy and vice versa. The aim of this paper is to optimize produced electrical energy from mechanical pressure. Therefore, the circular metal plate equipped with piezoelectric circular patch has been considered with simply and clamped supports. A comprehensive modeling, parametrical study and the effect of the boundary conditions on the performance of the microgenerator have been investigated. The system is under variable pressure from an oscillating pressure source. Results are presented for PZT and PMN-PT piezoelectric materials with steel and aluminum substrates. An optimal value for the radius and thickness of the piezoelectric layer with a special support condition has been obtained.

  19. Charged Particle Optics in Circular Higgs Factory

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yunhai [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-02-26

    Similar to a super B-factory, a circular Higgs factory will require strong focusing systems near the interaction points and a low-emittance lattice in arcs to achieve a factory luminosity. At electron beam energy of 120 GeV, beamstrahlung effects during the collision pose an additional challenge to the collider design. In particular, a large momentum acceptance at 2 percent level is necessary to retain an adequate beam lifetime. This turns out to be the most challenging aspect in the design of circular Higgs factory. In this paper, an example will be provided to illustrate the beam dynamics in circular Higgs factory, emphasizing on the chromatic optics. Basic optical modules and advanced analysis will be presented. Most important, we will show that 2% momentum aperture is achievable

  20. Circular object recognition based on shape parameters

    Institute of Scientific and Technical Information of China (English)

    Chen Aijun; Li Jinzong; Zhu Bing

    2007-01-01

    To recognize circular objects rapidly in satellite remote sensing imagery, an approach using their geometry properties is presented.The original image is segmented to be a binary one by one dimension maximum entropy threshold algorithm and the binary image is labeled with an algorithm based on recursion technique.Then, shape parameters of all labeled regions are calculated and those regions with shape parameters satisfying certain conditions are recognized as circular objects.The algorithm is described in detail, and comparison experiments with the randomized Hough transformation (RHT) are also provided.The experimental results on synthetic images and real images show that the proposed method has the merits of fast recognition rate, high recognition efficiency and the ability of anti-noise and anti-jamming.In addition, the method performs well when some circular objects are little deformed and partly misshapen.

  1. Chaotic Motion of Corrugated Circular Plates

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Large deflection theory of thin anisotropic circular plates was used to analyze the bifurcation behavior and chaotic phenomena of a corrugated thin circular plate with combined transverse periodic excitation and an in-plane static boundary load. The nonlinear dynamic equation for the corrugated plate was derived by employing Galerkin's technique. The critical conditions for occurrence of the homoclinic and subharmonic bifurcations as well as chaos were studied theoretically using the Melnikov function method. The chaotic motion was also simulated numerically using Maple, with the Poincaré map and phase curve used to evaluate when chaotic motion appears. The results indicate some chaotic motion in the corrugated plate. The method is directly applicable to chaotic analysis of an isotropic circular plate.

  2. Neural tube defects

    Directory of Open Access Journals (Sweden)

    M.E. Marshall

    1981-09-01

    Full Text Available Neural tube defects refer to any defect in the morphogenesis of the neural tube, the most common types being spina bifida and anencephaly. Spina bifida has been recognised in skeletons found in north-eastern Morocco and estimated to have an age of almost 12 000 years. It was also known to the ancient Greek and Arabian physicians who thought that the bony defect was due to the tumour. The term spina bifida was first used by Professor Nicolai Tulp of Amsterdam in 1652. Many other terms have been used to describe this defect, but spina bifida remains the most useful general term, as it describes the separation of the vertebral elements in the midline.

  3. X-ray tubes

    International Nuclear Information System (INIS)

    An improved form of x-ray tube is described which consists of a rotatable anode disc and an electron beam source enclosed in an envelope. The beam of electrons strikes the edge of the anode disc at an acute angle, producing x-rays which are transmitted through a window in the envelope. To improve performance and life of the anode disc it is additionally reciprocated back and forth along its axis of rotation. Dimensions are specified. (U.K.)

  4. Primary fallopian tube carcinoma

    Directory of Open Access Journals (Sweden)

    Mladenović-Segedi Ljiljana

    2009-01-01

    Full Text Available Introduction. Primary fallopian tube carcinoma is extremely rare, making 0.3-1.6% of all female genital tract malignancies. Although the etymology of this tumor is unknown, it is suggested to be associated with chronic tubal inflammation, infertility, tuberculous salpingitis and tubal endometriosis. High parity is considered to be protective. Cytogenetic studies show the disease to be associated with over expression of p53, HER2/neu and c-myb. There is also some evidence that BRCA1 and BRCA2 mutations have a role in umorogeneis. Clinical features. The most prevailing symptoms with fallopian tube carcinoma are abdominal pain, abnormal vaginal discharge/bleeding and the most common finding is an adnexal mass. In many patients, fallopian tube carcinoma is asymptomatic. Diagnosis. Due to its rarity, preoperative diagnosis of primary fallopian tube carcinoma is rarely made. It is usually misdiagnosed as ovarian carcinoma, tuboovarian abscess or ectopic pregnancy. Sonographic features of the tumor are non-specific and include the presence of a fluid-filled adnexal structure with a significant solid component, a sausage-shaped mass, a cystic mass with papillary projections within, a cystic mass with cog wheel appearance and an ovoid-shaped structure containing an incomplete separation and a highly vascular solid nodule. More than 80% of patients have elevated pretreatment serum CA-125 levels, which is useful in follow-up after the definite treatment. Treatment. The treatment approach is similar to that of ovarian carcinoma, and includes total abdominal hysterectomy and bilateral salpingo-oophorectomy. Staging is followed with chemotherapy.

  5. Fabrication of seamless calandria tubes

    International Nuclear Information System (INIS)

    Full text: Calandria tube is a large diameter, thin walled zircaloy-4 tube and is an important structural component of PHWR type of reactors. These tubes are lifetime components and remain during the full life of the reactor. Calandria tubes are classified as extremely thin walled tubes with a diameter to wall thickness ratio of around 96. Such thin walled tubes are conventionally produced by seam welded route comprising of extrusion of slabs followed by a series of hot and rolling passes, shaping into O-shape and eventual welding. An alternative and superior method of fabricating the calandria tubes, the seamless route, has been developed, which involves hot extrusion of mother blanks followed by three successive cold pilger reductions. Eccentricity correction of the extruded blanks is carried out on a special purpose grinding equipment to bring the wall thickness variation within permissible limits. Predominant wall thickness reductions are given during cold pilgering to ensure high Q-factor values. The texture in the finished tubes could be closely, controlled with an average fr value of 0.65. Pilgering parameters and tube guiding system have been specially designed to facilities rolling of thin walled tubes. Seamless calandria tubes have distinct advantages over welded tubes. In addition to the absence of weld, they are dimensionally more stable, lighter in weight and possess uniform grains with superior grain size. The cycle time from billet to finished product is substantially reduced and the product is amenable to high level of quality assurance. The most significant feature of the seamless route is its material recovery over welded route. Residual stresses measured in the tubes indicate that these are negligible and uniform along the length of the tube. In view of their superior quality, the first charge of seamless calandria tubes will be rolled into the first 500 MWe Pressurised Heavy Water Reactor at Tarapur

  6. Clogging of feeding tubes.

    Science.gov (United States)

    Marcuard, S P; Perkins, A M

    1988-01-01

    This is a report of an in vitro study evaluating clotting ability of some formulas with intact protein and hydrolyzed protein sources in a series of buffers ranging from a pH of 1 thru 10. The following 10 products were tested: Ensure Plus, Ensure, Enrich, Osmolite, Pulmocare, Citrotein, Resource, Vivonex TEN, Vital, and Hepatic Acid II. Protein (10 and 20 g/liter) was added to Citrotein and Ensure Plus. All formulas were tested at full and some at half strength. Clotting occurred only in premixed intact protein formulas (Pulmocare, Ensure Plus, Osmolite, Enrich, Ensure) and in Resource. No clotting was observed for Citrotein (intact protein formula in powder form), Vital, Vivonex TEN, and Hepatic Aid II. Adding protein did not cause or increase clotting. In summary, clotting of some liquid formula diet appears to be an important factor causing possible gastric feeding tube occlusion. The following measures may help in preventing this problem: flushing before and after aspirating for gastric residuals to eliminate acid precipitation of formula in the feeding tube, advance the nasogastric feeding tube into the duodenum if possible, and avoid mixing these products with liquid medications having a pH value of 5.0 or less. PMID:3138452

  7. Traveling-Wave Tubes

    Science.gov (United States)

    Kory, Carol L.

    1998-01-01

    The traveling-wave tube (TWT) is a vacuum device invented in the early 1940's used for amplification at microwave frequencies. Amplification is attained by surrendering kinetic energy from an electron beam to a radio frequency (RF) electromagnetic wave. The demand for vacuum devices has been decreased largely by the advent of solid-state devices. However, although solid state devices have replaced vacuum devices in many areas, there are still many applications such as radar, electronic countermeasures and satellite communications, that require operating characteristics such as high power (Watts to Megawatts), high frequency (below 1 GHz to over 100 GHz) and large bandwidth that only vacuum devices can provide. Vacuum devices are also deemed irreplaceable in the music industry where musicians treasure their tube-based amplifiers claiming that the solid-state and digital counterparts could never provide the same "warmth" (3). The term traveling-wave tube includes both fast-wave and slow-wave devices. This article will concentrate on slow-wave devices as the vast majority of TWTs in operation fall into this category.

  8. Domain structure of circular and ring magnets

    International Nuclear Information System (INIS)

    We present the results of a study of the domain structure and the magnetization reversal processes in arrays of circular and ring magnets, obtained by magnetic force microscopy and magnetization measurements. The particles, with outer diameter 0.55 and 2.2 μm, were made of Permalloy films of thickness 24 and 66 nm. In the circular elements two domain configurations were observed: a vortex structure with perpendicular magnetization at the core and a 'bud' state. In the ring elements the domain structure was found to depend on the ring width: a flux closed state was formed in wide rings and the 'onion' state was observed in narrow rings

  9. Circular economy in China and recommendations

    Institute of Scientific and Technical Information of China (English)

    Zhou Hongchun

    2006-01-01

    @@ It is an overall, urgent and long-term strategic task for China to vigorously develop the circular economy and build a resource-saving and environmental-friendly society. China is now at the accelerating stage of industrialization and urbanization.Lower per-capita resource amount and tendency of environmental deterioration has not been fundamentally averted. Therefore a circular economy development is an inevitable choice to realize the goal of building a well-off society, ensure sustainable development of national economy, and coordinate the relationship between mankind and nature.

  10. Circularly polarized U-Slot antenna

    OpenAIRE

    Tong, K. F.; Wong, T P

    2007-01-01

    Circularly polarized single-layer U-slot microstrip patch antenna has been proposed. The suggested asymmetrical U-slot can generate the two orthogonal modes for circular polarization without chamfering any corner of the probe-fed square patch microstrip antenna. A parametric study has been carried out to investigate the effects caused by different arm lengths of the U-slot. The thickness of the foam substrate is about 8.5% of the wavelength at the operating frequency. The 3 dB axial ratio ban...

  11. Broadband Suspended Microstrip Antenna For Circular Polarization

    OpenAIRE

    Kasabegoudar, VG; Vinoy, KJ

    2009-01-01

    In this paper we propose a circularly polarized (CP) microstrip antenna on a suspended substrate with a coplanar capacitive feed and a slot within the rectangular patch. The antenna has an axial ratio bandwidth (< 3 dB) of 7.1%. The proposed antenna exhibits a much higher impedance bandwidth of about 49% (S11 < -10 dB) and also yields return loss better than -15 dB in the useful range of circular polarization. Measured characteristics of the antenna are in good agreement with the simulated re...

  12. Free vibrations of circular cylindrical shells

    CERN Document Server

    Armenàkas, Anthony E; Herrmann, George

    2013-01-01

    Free Vibrations of Circular Cylindrical Shells deals with thin-walled structures that undergo dynamic loads application, thereby resulting in some vibrations. Part I discusses the treatment of problems associated with the propagation of plane harmonic waves in a hollow circular cylinder. In such search for solutions, the text employs the framework of the three-dimensional theory of elasticity. The text explains the use of tables of natural frequencies and graphs of representative mode shapes of harmonic elastic waves bounding in an infinitely long isotropic hollow cylinder. The tables are

  13. Circularly Polarized Luminescence from Simple Organic Molecules.

    Science.gov (United States)

    Sánchez-Carnerero, Esther M; Agarrabeitia, Antonia R; Moreno, Florencio; Maroto, Beatriz L; Muller, Gilles; Ortiz, María J; de la Moya, Santiago

    2015-09-21

    This article aims to show the identity of "circularly polarized luminescent active simple organic molecules" as a new concept in organic chemistry due to the potential interest of these molecules, as availed by the exponentially growing number of research articles related to them. In particular, it describes and highlights the interest and difficulty in developing chiral simple (small and non-aggregated) organic molecules able to emit left- or right-circularly polarized light efficiently, the efforts realized up to now to reach this challenging objective, and the most significant milestones achieved to date. General guidelines for the preparation of these interesting molecules are also presented. PMID:26136234

  14. Rectangular-to-circular groove waveguide junction

    Institute of Scientific and Technical Information of China (English)

    CUI; Licheng; (崔立成); YANG; Hongsheng; (杨鸿生)

    2003-01-01

    Mode matching method is used to analyze the scattering characteristics of the rectangular-to-circular groove waveguide junction. Firstly, the scattering matrix equation is obtained by matching the electromagnetic fields at the boundary of the junction. The scattering coefficients can be obtained from the equation. Secondly the scattering characteristics of the iris with rectangular window positioned in circular groove waveguide are briefly analyzed. Thirdly, the convergent problem is discussed and the numerical results are given. At last experiment is made and good agreement is found between the calculated results and the measured results.

  15. Augmentation of laminar flow and heat transfer in flat tubes by means of helical screw-tape inserts

    International Nuclear Information System (INIS)

    The heat transfer a characteristics and friction factor in the horizontal double pipes of flat tubes with full length helical screw element of different twist ratio and helical screw inserts with different spacer length are investigated. Cold and hot water are used as working fluid in tube side and shell side respectively. The experiments covered a range of Reynolds numbers 5.7 x 102 ≤ Re ≤ 1.31 x 103. The effect of spacer length on the heat transfer augmentation and friction factor and the effect of twist ratio on heat transfer augmentation and friction factor have been presented separately. The study shows that, the Nusslet number (Nu) and friction factor (f) decrease with the increase of S or Y for flat tube. The comparison between the data of present plain circular with that of previous plain circular tube showed a good agreement between them but the data of present plain flat tube showed a higher in heat transfer and pressure drop than that of plain circular tube. The correlations of average Nusselt number and friction factor with Re, S and Y are presented.

  16. Augmentation of laminar flow and heat transfer in flat tubes by means of helical screw-tape inserts

    Energy Technology Data Exchange (ETDEWEB)

    Ibrahim, E.Z., E-mail: emadz20022000@yahoo.co [Faculty of Engineering, Zagazig University, 44519 Zagazig (Egypt)

    2011-01-15

    The heat transfer a characteristics and friction factor in the horizontal double pipes of flat tubes with full length helical screw element of different twist ratio and helical screw inserts with different spacer length are investigated. Cold and hot water are used as working fluid in tube side and shell side respectively. The experiments covered a range of Reynolds numbers 5.7 x 10{sup 2} {<=} Re {<=} 1.31 x 10{sup 3}. The effect of spacer length on the heat transfer augmentation and friction factor and the effect of twist ratio on heat transfer augmentation and friction factor have been presented separately. The study shows that, the Nusslet number (Nu) and friction factor (f) decrease with the increase of S or Y for flat tube. The comparison between the data of present plain circular with that of previous plain circular tube showed a good agreement between them but the data of present plain flat tube showed a higher in heat transfer and pressure drop than that of plain circular tube. The correlations of average Nusselt number and friction factor with Re, S and Y are presented.

  17. CRL X-RAY TUBE

    OpenAIRE

    Kolchevsky, N. N.; Petrov, P. V.

    2015-01-01

    A novel types of X-ray tubes with refractive lenses are proposed. CRL-R X-ray tube consists of Compound Refractive Lens- CRL and Reflection X-ray tube. CRL acts as X-ray window. CRL-T X-ray consists of CRL and Transmission X-ray tube. CRL acts as target for electron beam. CRL refractive lens acts as filter, collimator, waveguide and focusing lens. Properties and construction of the CRL X-ray tube are discussed.

  18. Spectrometer beam tube dimensional optimization

    International Nuclear Information System (INIS)

    This project examined the optimization of the design of a beam tube. An ANSYS model was used to find the minimum tube thickness and the best camber in a beam tube under vacuum and preloaded by a pair of magnet poles. After the tube was modeled one version of it was built for use in the accelerator. This beam tube was put under a vacuum and the dimensional changes were recorded and compared to the ANSYS predictions. These deflection results were quite close to the predicted numbers and would suggest that the stresses are similar to the predictions as well

  19. Circular depolarization ratios of single water droplets and finite ice circular cylinders: a modeling study

    Directory of Open Access Journals (Sweden)

    M. Nicolet

    2011-11-01

    Full Text Available Computations of the phase matrix elements for single water droplets and ice crystals in fixed orientations are presented to determine if circular depolarization δ±C is more accurate than linear depolarization for phase discrimination. T-matrix simulations were performed to calculate right-handed and left-handed circular depolarization ratios δ+C, respectively δ−C and to compare them with linear ones. Ice crystals are assumed to have a circular cylindrical shape where their surface-equivalent diameters range up to 5 μm. The circular depolarization ratios of ice particles were generally higher than linear depolarization and depended mostly on the particle orientation as well as their sizes. The fraction of non-detectable ice crystals (δ < 0.05 was smaller considering a circular polarized light source, reaching 4.5%. However, water droplets also depolarized light circularly for scattering angles smaller than 179° and size parameters smaller than 6 at side- and backscattering regions. Differentiation between ice crystals and water droplets might be difficult for experiments performing at backscattering angles which deviate from 180° unlike lidar applications. If the absence of the liquid phase is confirmed, the use of circular depolarization in single particle detection is more sensitive and less affected by particle orientation.

  20. Reliability of steam generator tubing

    Energy Technology Data Exchange (ETDEWEB)

    Kadokami, E. [Mitsubishi Heavy Industries Ltd., Hyogo-ku (Japan)

    1997-02-01

    The author presents results on studies made of the reliability of steam generator (SG) tubing. The basis for this work is that in Japan the issue of defects in SG tubing is addressed by the approach that any detected defect should be repaired, either by plugging the tube or sleeving it. However, this leaves open the issue that there is a detection limit in practice, and what is the effect of nondetectable cracks on the performance of tubing. These studies were commissioned to look at the safety issues involved in degraded SG tubing. The program has looked at a number of different issues. First was an assessment of the penetration and opening behavior of tube flaws due to internal pressure in the tubing. They have studied: penetration behavior of the tube flaws; primary water leakage from through-wall flaws; opening behavior of through-wall flaws. In addition they have looked at the question of the reliability of tubing with flaws during normal plant operation. Also there have been studies done on the consequences of tube rupture accidents on the integrity of neighboring tubes.

  1. Explosive Tube-to-fitting Joining of Small-diameter Tubes

    Science.gov (United States)

    Bement, L. J.

    1985-01-01

    An effort is currently under way by NASA Marshall Space Flight Center to upgrade the space shuttle main engine through the use of improved materials and processes. Under consideration is the use of the Langley Research Center explosive seam welding process. The objective is to demonstrate the feasibility of joining space shuttle main engine tube to fitting components in an oxygen heat exchanger, using the NASA LaRC explosive seam welding process. It was concluded that LaRC explosive joining is viable for this application; that there is no incompatability of materials; that ultrasonic inspection is the best nondestructive testing method; and that the .500 DIA joint experiences interface problems.

  2. Microdischarges in DC accelerator tubes

    International Nuclear Information System (INIS)

    Voltage tests on the Daresbury ceramic/titanium accelerator tube have shown that microdischarges play an important role in the conditioning process. It has been found that the voltage onset for microdischarges in a tube is dependent on the surface contamination of the electrodes and the tube geometry (in particular the tube length). This geometrical effect can be related to the trajectories of secondary ions emitted from the electrode surfaces. Sensitive diagnostic techniques have been developed to study the mass and energy distribution of ions emitted along the axis of the tube during these predischarges. The energy distribution of protons (and H- ions) can be related to the origins of the discharges in the tube. Detailed results are presented for a particular tube geometry. (author)

  3. Electron Interference in Molecular Circular Polarization Attosecond XUV Photoionization

    Directory of Open Access Journals (Sweden)

    Kai-Jun Yuan

    2015-01-01

    Full Text Available Two-center electron interference in molecular attosecond photoionization processes is investigated from numerical solutions of time-dependent Schrödinger equations. Both symmetric H\\(_2^+\\ and nonsymmetric HHe\\(^{2+}\\ one electron diatomic systems are ionized by intense attosecond circularly polarized XUV laser pulses. Photoionization of these molecular ions shows signature of interference with double peaks (minima in molecular attosecond photoelectron energy spectra (MAPES at critical angles \\(\\vartheta_c\\ between the molecular \\(\\textbf{R}\\ axis and the photoelectron momentum \\(\\textbf{p}\\. The interferences are shown to be a function of the symmetry of electronic states and the interference patterns are sensitive to the molecular orientation and pulse polarization. Such sensitivity offers possibility for imaging of molecular structure and orbitals.

  4. Ultrasonic inspection of tube to tube plate welds

    International Nuclear Information System (INIS)

    To monitor the deterioration of a weld between a tube and tube plate which has been repaired by a repair sleeve inside the tube and brazed at one end to the tube, ultrasound from a crystal at the end of a rod is launched, in the form of Lamb-type waves, into the tube through the braze and allowed to travel along the tube to the weld and be reflected back along the tube. The technique may also be used for the type of heat exchanger in which, during construction, the tubes are welded to the tube plate via external sleeves in which case the ultrasound is used in a similar manner to inspect the sleeve/tube plate weld. an electromagnetic transducer may be used to generate the ultrasound. The ultrasonic head comprising the crystal and an acoustic baffle is mounted on a Perspex (RTM) rod which may be rotated by a stepping motor. Echo signals from the region of deterioration may be isolated by use of a time gate in the receiver. The device primarily detects circumferentially orientated cracks, and may be used in heat exchangers in nuclear power plants. (author)

  5. Structural response of circular concrete filled tube piers in integral bridges

    OpenAIRE

    Kovac, Borisa

    2010-01-01

    Nowadays most of the bridges are designed with movable joints and bearings. They are used to allow for bridge deck displacements produced by: expansion and contraction of the bridge deck due to temperature changes, breaking or accelerating forces of vehicles and by long term changes of concrete such as creeping and shrinking. Joints and bearings are susceptible to durability problems and require maintenance and replacements. In order to reduce the maintenance costs and to lower the init...

  6. DNS of forced gas flows in circular tubes at sub-turbulent flow

    International Nuclear Information System (INIS)

    Full text of publication follows: A direct numerical simulation (DNS) with turbulent transport of a variable property has been carried out to grasp and understand a laminarization phenomena caused by a strong heating. In this study, the inlet Reynolds number based on a bulk velocity and a pipe diameter was set to be constant; Re = 6000. The temperature distribution taken from the experiments by Shehata and McEligot (1998) was applied to the wall as a thermal boundary condition. Their experiments concentrated on three characteristics cases with gas property variation: turbulent, laminarizing and intermediate or 'sub-turbulent'. In our previous study regarding the variable property turbulent pipe flow (Satake et al., 2000), the DNS result has been shown in good agreement with one case for their experimental data (RUN445, laminarizing case). In present results, the flow parameter was set to be RUN635 and RUN618 by Shehata and McEligot (1998). The number of computational grids used in this study was 768 x 64 x 128 in the z-, r- and Φ-directions, respectively. The turbulent quantities such as the mean flow, temperature fluctuations, turbulent stresses and the turbulent statistics were obtained via present DNS. The turbulent drag for RUN635 decreases along the stream-wise direction. The turbulent intensities also reduced for RUN635. But in RUN618, the turbulent intensity for stream-wise component still remains to the stream direction. The reason of these phenomena can be considered that the fluid property cannot change for developing temperature boundary layer. That is, the developing the velocity boundary layer delay for the developing thermal boundary layer. The pipe length as a computational domain is exactly the same one of the experimental set-up (Shehata and McEligot, 1998). The experimental data are provided as a basis of the comparison with the computational results. This condition exactly corresponds to the RUN635 and RUN618 of the Shehata and McEligot's experiments. Mean velocity profiles with heating via DNS and the experimental result are shown. Regarding the results with heating obtained from the DNS and the experiment, the friction velocity is increased by the properties change near the wall region due to the heating eventually the slope decreases in the logarithmic region. This result is in good agreement with that of the experimental data. (authors)

  7. A simple heat transfer correlation for SC fluid flow in circular tubes

    International Nuclear Information System (INIS)

    This paper presents a new method of heat transfer prediction in supercritical fluids. Emphasis is put on the simplicity of the correlation structure and its explicit coupling with physical phenomena. Assessment of qualitative behaviour of heat transfer is carried out based on existing test data and experience gathered in the open literature. Based on phenomenological analysis and test data evaluation, a single dimensionless number, the acceleration number, is introduced to correct the deviation of heat transfer from its conventional behaviour which is predicted by the Dittus-Boelter equation. The new correlation structure excludes direct dependence of heat transfer coefficient on the wall surface temperature, and eliminates possible numerical convergence. The uncertainty analysis of test data provides information about the sources and the levels of uncertainties of various parameters, and is highly required for the selection of both the dimensionless parameters implemented into the heat transfer correlation and the test data for the development and validation of new correlations. Comparison of various heat transfer correlations with the selected test data shows that the new correlation gives better agreement with the test data than other correlations selected from the open literature. (author)

  8. Heat transfer augmentation of a circular pipe flow using nano-particle layers

    Energy Technology Data Exchange (ETDEWEB)

    Yamagishi, Akira; Yuki, Kazuhisa; Sato, Tomoaki; Hashizume, Hidetoshi [Tohoku Univ. (Japan). Dept. of Quantum Science and Energy Engineering; Kunugi, Tomoaki [Kyoto Univ. (Japan). Faculty of Engineering; Sagara, Akio [National Inst. for Fusion Science (Japan)

    2007-07-01

    For the advanced fusion reactor FFHR2 (Force Free Helical Reactor) that has been proposed by NIFS, molten salt Flibe (LiF:BeF2=64:36) breeder blanket system is selected because of Flibe's features such as chemical stability, low-pressure operation and low electric conductivity. The Flibe is however high Prandtl number fluid since it has high viscosity and low thermal conductivity. Therefore its heat transfer performance is low compared with liquid Li or Pb-Li. In addition to heat removal of 1MW/m2 on the first wall, electrolysis of molten salt due to MHD effect will take place under high flow rate condition. This indicates that heat transfer enhancement under low flow rate is essential for the Flibe blanket system. In our laboratory, heat transfer characteristics of molten salt HTS (KNO3:NaNO2:NaNO3=53:40:7), have been evaluated, which is used as a simulant fluid of Flibe from the points of view of Be's toxicity and similar Prandtl number. In this paper, we adopt nano-particle layer method to form nano{proportional_to}micro scale structure on a heating surface using an acid or an alkali includes nano particles. There exist two methods to form nano particle layer. One is NPLS (Nano Particle Layer Structure) method which uses a chemical etching with an acid or an alkali including copper-oxide nano-particles. The other is FP (Fine Particle) method which employs electroless plating with inorganic metal salt solution. At first, immersion experiments of NPLS or FP layers into melted HTS shows that erosion of the FP sample is much less than that of the NPLS sample. Furthermore, a forced-convention heat transfer experiments with a circular tube whose inner surface has the nano-particle layer by the FP method is carried out in a large molten salt circulating loop named as TNT loop. Results show that average Nusselt numbers of the circular tube flow are about 1.3 times higher than that of a bared tube in the range of 3000

  9. CFD simulation of mechanical draft tube mixing in anaerobic digester tanks.

    Science.gov (United States)

    Meroney, Robert N; Colorado, P E

    2009-03-01

    Computational Fluid Dynamics (CFD) was used to simulate the mixing characteristics of four different circular anaerobic digester tanks (diameters of 13.7, 21.3, 30.5, and 33.5m) equipped with single and multiple draft impeller tube mixers. Rates of mixing of step and slug injection of tracers were calculated from which digester volume turnover time (DVTT), mixture diffusion time (MDT), and hydraulic retention time (HRT) could be calculated. Washout characteristics were compared to analytic formulae to estimate any presence of partial mixing, dead volume, short-circuiting, or piston flow. CFD satisfactorily predicted performance of both model and full-scale circular tank configurations. PMID:19135698

  10. Beam Dynamics and Beam Losses - Circular Machines

    CERN Document Server

    Kain, V

    2016-01-01

    A basic introduction to transverse and longitudinal beam dynamics as well as the most relevant beam loss mechanisms in circular machines will be presented in this lecture. This lecture is intended for physicists and engineers with little or no knowledge of this subject.

  11. The Global Future Circular Colliders Effort

    CERN Document Server

    Benedikt, Michael

    2013-01-01

    This presentation has been given during the P5 Workshop at BNL Brookhaven (US). It contains - Global Future Circular Collier Studies Overview and Status - Main challenges and R&D areas for hadron collider - Main challenges and R&D areas for lepton collider - Conclusions

  12. Circular Vibration Planing of Inconel 718

    Science.gov (United States)

    Hettiarachchi, Nandita Kalyanakumara; Moriwaki, Toshimichi; Shibasaka, Toshiro; Nakamoto, Keiichi

    Circular vibration milling (CVM) is achieved by vibrating a milling cutter about the machine tool spindle axis in a circular path, in addition to its rotary motion. CVM has been proven capable of producing better surface finishes on difficult to cut materials. However, the CVM process is far slower than conventional milling process. In circular vibration planing (CVP) process, the cutting tool is clamped without rotation and fed at a speed comparable to the feed speed of conventional milling. By superimposing circular vibration motion, necessary cutting speed could be achieved keeping the feed speed at realistic values. Inconel 718 was machined by CVP and conventional milling at a similar feed rate. It was observed that CVP could reduce tool wear and hence produce better surface finishes than conventional milling. A geometric simulation showed a major difference between uncut chip shapes of the two processes. The difference of uncut chip shapes suggests that in CVP process, less rubbing occurs between tool flank face and work before the tool penetrates in to the work to form a chip. The reduced rubbing of the flank face is proposed as the reson for reduced tool wear in CVP when compared with conventional milling.

  13. Numerical simulation of flow past circular duct

    Directory of Open Access Journals (Sweden)

    Ze-gao YIN

    2010-06-01

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

  14. Dynamics of the circular bosonic string

    International Nuclear Information System (INIS)

    After a brief discussion about the Nambu-Goto action, we introduce the concept of transverse velocity and find it for a closed circular bosonic string, then we study and solve the string's equations of movement by using the energy conservation law and finally we sketch its corresponding world sheet. (author).

  15. Discrete Fresnel Transform and Its Circular Convolution

    CERN Document Server

    Ouyang, Xing; Gunning, Fatima; Zhang, Hongyu; Guan, Yong Liang

    2015-01-01

    Discrete trigonometric transformations, such as the discrete Fourier and cosine/sine transforms, are important in a variety of applications due to their useful properties. For example, one well-known property is the convolution theorem for Fourier transform. In this letter, we derive a discrete Fresnel transform (DFnT) from the infinitely periodic optical gratings, as a linear trigonometric transform. Compared to the previous formulations of DFnT, the DFnT in this letter has no degeneracy, which hinders its mathematic applications, due to destructive interferences. The circular convolution property of the DFnT is studied for the first time. It is proved that the DFnT of a circular convolution of two sequences equals either one circularly convolving with the DFnT of the other. As circular convolution is a fundamental process in discrete systems, the DFnT not only gives the coefficients of the Talbot image, but can also be useful for optical and digital signal processing and numerical evaluation of the Fresnel ...

  16. Helically corrugated circular waveguides as antenna feeders

    Science.gov (United States)

    Jecko, F.; Papiernik, A.

    1983-07-01

    Rotation of the plane of polarization of the TE(11)-mode is predicted and observed in a helically corrugated circular waveguide. Rotation is suppressed by a longitudinal deformation produced on the corrugation. This modified structure can be used as an antenna feeder with low losses.

  17. Numerical simulation of flow past circular duct

    Institute of Scientific and Technical Information of China (English)

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

    2010-01-01

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

  18. Oblique stability of circularly polarized MHD waves

    International Nuclear Information System (INIS)

    The stability of finite-amplitude weakly dispersive circularly polarized MHD wave trains with respect to oblique modulations is investigated. The mathematical model is a multi-dimensional extension of the DNLS equation. It is found that the right-hand-polarized wave, which is stable with respect to parallel modulations, is unstable with respect to certain oblique modulations for most primary wavenumbers. (author)

  19. Time can't be circular

    CERN Multimedia

    2003-01-01

    "Delivering the Albert Einstein lecture at the Centre for Philosophy and Foundations of Science on Tuesday, Nobel Laureate Professor Gerard Hooft said that any notion of time can not be circular or have loops or multi dimensionality" (1/2 page).

  20. Nuclear spin circular dichroism in fullerenes

    Czech Academy of Sciences Publication Activity Database

    Straka, Michal

    Brno : Masaryk University Press, 2015 - (Sklenář, V.). s. 153 ISBN 978-80-210-7890-1. [EUROMAR 2015. 05.07.2015-10.07.2015, Praha] R&D Projects: GA ČR(CZ) GA14-03564S Institutional support: RVO:61388963 Keywords : nuclear spin circular dichroism * fullerenes Subject RIV: CF - Physical ; Theoretical Chemistry

  1. Vibrational circular dichroism of nucleic acids

    Czech Academy of Sciences Publication Activity Database

    Andrushchenko, Valery; Wieser, H.; Bouř, Petr

    Brescia, 2009. s. 60-60. [International Conference on Circular Dichroism /12./. Interdisciplinary Symposium on Biological Chirality /5./. 30.08.2009-04.09.2009, Brescia] Institutional research plan: CEZ:AV0Z40550506 Keywords : VCD * G-quadruplex Subject RIV: CF - Physical ; Theoretical Chemistry

  2. Self-organization in circular shear layers

    DEFF Research Database (Denmark)

    Bergeron, K.; Coutsias, E.A.; Lynov, Jens-Peter;

    1996-01-01

    Experiments on forced circular shear layers performed in both magnetized plasmas and in rotating fluids reveal qualitatively similar self-organization processes leading to the formation of patterns of coherent vortical structures with varying complexity. In this paper results are presented from...

  3. CIRCULAR CHROMATIC NUMBER AND MYCIELSKI GRAPHS

    Institute of Scientific and Technical Information of China (English)

    Liu Hongmei

    2006-01-01

    For a general graph G, M(G) denotes its Mycielski graph. This article gives a number of new sufficient conditions for G to have the circular chromatic number xc (M(G))equals to the chromatic number x(M(G)), which have improved some best sufficient conditions published up to date.

  4. Senior Centers

    Medline Plus

    Full Text Available ... to do as long as they can. Senior centers, adult day care, transportation, and meals programs are ... older adults to remain in their homes. Senior centers are places where older adults who live independently ...

  5. Ultrasonic excitation of a bubble inside a deformable tube: Implications for ultrasonically induced hemorrhage

    OpenAIRE

    Miao, Hongyu; Gracewski, Sheryl M.; Dalecki, Diane

    2008-01-01

    Various independent investigations indicate that the presence of microbubbles within blood vessels may increase the likelihood of ultrasound-induced hemorrhage. To explore potential damage mechanisms, an axisymmetric coupled finite element and boundary element code was developed and employed to simulate the response of an acoustically excited bubble centered within a deformable tube. As expected, the tube mitigates the expansion of the bubble. The maximum tube dilation and maximum hoop stress...

  6. Building lab-scale x-ray tube based irradiators

    Science.gov (United States)

    Haff, Ron; Jackson, Eric; Gomez, Joseph; Light, Doug; Follett, Peter; Simmons, Greg; Higbee, Brad

    2016-04-01

    Here we report the use of x-ray tube based irradiators as alternatives to gamma sources for laboratory scale irradiation. Irradiators were designed with sample placement in closest possible proximity to the source, allowing high dose rates for small samples. Designs using 1000 W x-ray tubes in single tube, double tube, and four tube configurations are described, as well as various cabinet construction techniques. Relatively high dose rates were achieved for small samples, demonstrating feasibility for laboratory based irradiators for research purposes. Dose rates of 9.76, 5.45, and 1.7 Gy/min/tube were measured at the center of a 12.7 cm container of instant rice at 100 keV, 70 keV, and 40 keV, respectively. Dose uniformity varies dramatically as the distance from source to container. For 2.54 cm diameter sample containers containing adult Navel Orangeworm, dose rates of 50-60 Gy/min were measured in the four tube system.

  7. Does circular polarisation reveal the rotation of quasar engines?

    CERN Document Server

    Ensslin, T A

    2003-01-01

    Many radio sources like quasars, blazars, radio galaxies, and micro-quasars exhibit circular polarisation (CP) with surprising temporal persistent handedness. As a possible explanation we propose that the CP is due to Faraday conversion (FC) of linear polarisation synchrotron light which propagates along a line-of-sight (LOS) through twisted magnetic fields. The rotational nature of accretion flows onto black holes naturally generates the required magnetic twist in the emission region, independent of whether it is a jet or an ADAF. The expected twist in both types of flows is of the order of what is required for optimal CP generation, relaxing constraints on the plasma parameters, that were given in scenarios which rely on Faraday rotation (FR). The mechanism works in electron-positron (e+/e-) as well as electron-proton (e/p) plasma. In the latter case, the emission region should consist of individual flux tubes with independent polarities in order to suppress too strong FR. The predominant CP is expected to ...

  8. Ultrasonic excitation of a bubble inside a deformable tube: implications for ultrasonically induced hemorrhage.

    Science.gov (United States)

    Miao, Hongyu; Gracewski, Sheryl M; Dalecki, Diane

    2008-10-01

    Various independent investigations indicate that the presence of microbubbles within blood vessels may increase the likelihood of ultrasound-induced hemorrhage. To explore potential damage mechanisms, an axisymmetric coupled finite element and boundary element code was developed and employed to simulate the response of an acoustically excited bubble centered within a deformable tube. As expected, the tube mitigates the expansion of the bubble. The maximum tube dilation and maximum hoop stress were found to occur well before the bubble reached its maximum radius. Therefore, it is not likely that the expanding low pressure bubble pushes the tube wall outward. Instead, simulation results indicate that the tensile portion of the acoustic excitation plays a major role in tube dilation and thus tube rupture. The effects of tube dimensions (tube wall thickness 1-5 microm), material properties (Young's modulus 1-10 MPa), ultrasound frequency (1-10 MHz), and pressure amplitude (0.2-1.0 MPa) on bubble response and tube dilation were investigated. As the tube thickness, tube radius, and acoustic frequency decreased, the maximum hoop stress increased, indicating a higher potential for tube rupture and hemorrhage. PMID:19062875

  9. Excel Center

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Citigroup,one of the World top 500 companies,has now settled in Excel Center,Financial Street. The opening ceremony of Excel Center and the entry ceremony of Citigroup in the center were held on March 31.Government leaders of Xicheng District,the Excel CEO and the heads of Asia-Pacific Region leaders of Citibank all participated in the ceremony.

  10. Fabrication of seamless calandria tubes by cold pilgering route using 3-pass and 2-pass schedules

    Science.gov (United States)

    Saibaba, N.

    2008-12-01

    Calandria tube is a large diameter, extremely thin walled zirconium alloy tube which has diameter to wall thickness ratio as high as 90-95. Such tubes are conventionally produced by the 'welded route', which involves extrusion of slabs followed by a series of hot and cold rolling passes, intermediate anneals, press forming of sheets into circular shape and closing the gap by TIG welding. Though pilgering is a well established process for the fabrication of seamless tubes, production of extremely thin walled tubes offers several challenges during pilgering. Nuclear fuel complex (NFC), Hyderabad, has successfully developed a process for the production of Zircaloy-4 calandria tubes by adopting the 'seamless route' which involves hot extrusion of mother blanks followed by three-pass pilgering or two-pass pilgering schedules. This paper deals with standardization of the seamless route processes for fabrication of calandria tubes, comparison between the tubes produced by 2-pass and 3-pass pilgering schedules, role of ultrasonic test charts for control of process parameters, development of new testing methods for burst testing and other properties.

  11. Fabrication of seamless calandria tubes by cold pilgering route using 3-pass and 2-pass schedules

    International Nuclear Information System (INIS)

    Calandria tube is a large diameter, extremely thin walled zirconium alloy tube which has diameter to wall thickness ratio as high as 90-95. Such tubes are conventionally produced by the 'welded route', which involves extrusion of slabs followed by a series of hot and cold rolling passes, intermediate anneals, press forming of sheets into circular shape and closing the gap by TIG welding. Though pilgering is a well established process for the fabrication of seamless tubes, production of extremely thin walled tubes offers several challenges during pilgering. Nuclear fuel complex (NFC), Hyderabad, has successfully developed a process for the production of Zircaloy-4 calandria tubes by adopting the 'seamless route' which involves hot extrusion of mother blanks followed by three-pass pilgering or two-pass pilgering schedules. This paper deals with standardization of the seamless route processes for fabrication of calandria tubes, comparison between the tubes produced by 2-pass and 3-pass pilgering schedules, role of ultrasonic test charts for control of process parameters, development of new testing methods for burst testing and other properties

  12. Novel rotating field probe for inspection of tubes

    Science.gov (United States)

    Xin, J.; Tarkleson, E.; Lei, N.; Udpa, L.; Udpa, S. S.

    2012-05-01

    Inspection of steam generator tubes in nuclear power plants is extremely critical for safe operation of the power plant. In the nuclear industry, steam generator tube inspection using eddy current techniques has evolved over the years from a single bobbin coil, to rotating probe coil (RPC) and array probe, in an attempt to improve the speed and reliability of inspection. The RPC probe offers the accurate spatial resolution but involves complex mechanical rotation. This paper presents a novel design of eddy current probes based on rotating fields produced by three identical coils excited by a balanced three-phase supply. The sensor thereby achieves rotating probe functionality by electronic means and eliminates the need for mechanical rotation. The field generated by the probe is largely radial that result in induced currents that flow circularly around the radial axis and rotating around the tube at a synchronous speed effectively producing induced eddy currents that are multidirectional. The probe will consequently be sensitive to cracks of all orientations in the tube wall. The finite element model (FEM) results of the rotating fields and induced currents are presented. A prototype probe is being built to validate simulation results.

  13. Device for reshaping the end of steam generator tube

    International Nuclear Information System (INIS)

    The device comprises a support fixed to the inlet face of the steam generator tube plate, a cylindrical sleeve integral with the support and coaxial to the tube, and an assembly which moves within the sleeve in the axial direction with regard to the tube. The sleeve is the chamber of a pneumatic and hydraulic cylinder. The movable assembly comprises an axial rod integral with the piston of the cylinder and a reshaping screw. The reshaping screw rotates, and is connected to the rod by means of centering and holding means. These means constitute an articulated assembly operating while the screw penetrates, and a rigid centering device with a rigid support surface when the screw withdraws. The invention concerns more particularly, the maintenance operations of pressurized water nuclear reactors

  14. High-cadence and High-resolution Hα Imaging Spectroscopy of a Circular Flare's Remote Ribbon with IBIS

    Science.gov (United States)

    Deng, Na; Tritschler, Alexandra; Jing, Ju; Chen, Xin; Liu, Chang; Reardon, Kevin; Denker, Carsten; Xu, Yan; Wang, Haimin

    2013-06-01

    We present an unprecedented high-resolution Hα imaging spectroscopic observation of a C4.1 flare taken with the Interferometric Bidimensional Spectrometer (IBIS) in conjunction with the adaptive optics system at the 76 cm Dunn Solar Telescope on 2011 October 22 in the active region NOAA 11324. Such a two-dimensional spectroscopic observation covering the entire evolution of a flare ribbon with high spatial (0.''1 pixel-1 image scale), cadence (4.8 s), and spectral (0.1 Å step size) resolution is rarely reported. The flare consists of a main circular ribbon that occurred in a parasitic magnetic configuration and a remote ribbon that was observed by the IBIS. Such a circular-ribbon flare with a remote brightening is predicted in three-dimensional fan-spine reconnection but so far has been rarely studied. During the flare impulsive phase, we define "core" and "halo" structures in the observed ribbon based on IBIS narrowband images in the Hα line wing and line center. Examining the Hα emission spectra averaged in the flare core and halo areas, we find that only those from the flare cores show typical nonthermal electron beam heating characteristics that have been revealed by previous theoretical simulations and observations of flaring Hα line profiles. These characteristics include broad and centrally reversed emission spectra, excess emission in the red wing with regard to the blue wing (i.e., red asymmetry), and redshifted bisectors of the emission spectra. We also observe rather quick timescales for the heating (~30 s) and cooling (~14-33 s) in the flare core locations. Therefore, we suggest that the flare cores revealed by IBIS track the sites of electron beam precipitation with exceptional spatial and temporal resolution. The flare cores show two-stage motion (a parallel motion along the ribbon followed by an expansion motion perpendicular to the ribbon) during the two impulsive phases of the flare. Some cores jump quickly (30 km s-1) between discrete

  15. Modeling the Effects of Viscosity and Thermal Conduction on Acoustic Propagation in Rigid Tubes with Various Cross-Sectional Shapes

    DEFF Research Database (Denmark)

    Christensen, René

    2011-01-01

    When modeling acoustics with viscothermal effects included, typically of importance for narrow tubes and slits, one can often use the so-called low reduced frequency model. With this model a characteristic length is assumed for which the sound pressure is constant. For example for a circular cyli...

  16. Lattice Boltzmann simulation of flow around two, three and four circular cylinders in close proximity

    Science.gov (United States)

    Kang, XiuYing; Su, YanPing

    2012-10-01

    Cross-flows around two, three and four circular cylinders in tandem, side-by-side, isosceles triangle and square arrangements are simulated using the incompressible lattice Boltzmann method with a second-order accurate curved boundary condition at Reynolds number 200 and the cylinder center-to-center transverse or/and longitudinal spacing 1.5 D, where D is the identical circular cylinder diameter. The wake patterns, pressure and force distributions on the cylinders and mechanism of flow dynamics are investigated and compared among the four cases. The results also show that flows around the three or four cylinders significantly differ from those of the two cylinders in the tandem and side-by-side arrangements although there are some common features among the four cases due to their similarity of structures, which are interesting, complex and useful for practical applications. This study provides a useful database to validate the simplicity, accuracy and robustness of the Lattice Boltzmann method.

  17. Solid Angle Computations for a Circular Radiator and a Circular Detector

    International Nuclear Information System (INIS)

    The problem of particle detection, when using an isotropic neutron point source at different distances from a circular target or a radioactive source as seen by a circular detector, e. g. a solid state counter, is dealt with. Tables are given for different distances of the source when the reaction at the target has an isotropic or a cosine angular distribution in the laboratory system

  18. Circular depolarization ratios of single water droplets and finite ice circular cylinders: a modeling study

    Directory of Open Access Journals (Sweden)

    M. Nicolet

    2012-05-01

    Full Text Available Computations of the phase matrix elements for single water droplets and ice crystals in fixed orientations are presented to determine if circular depolarization δC is more accurate than linear depolarization for phase discrimination. T-matrix simulations were performed to calculate right-handed and left-handed circular depolarization ratios δ+C, respectively δ−C and to compare them with linear ones. Ice crystals are assumed to have a circular cylindrical shape where their surface-equivalent diameters range up to 5 μm. The circular depolarization ratios of ice particles were generally higher than linear depolarization and depended mostly on the particle orientation as well as their sizes. The fraction of non-detectable ice crystals (δ<0.05 was smaller considering a circular polarized light source, reaching 4.5%. However, water droplets also depolarized light circularly for scattering angles smaller than 179° and size parameters smaller than 6 at side- and backscattering regions. Differentiation between ice crystals and water droplets might be difficult for experiments performed at backscattering angles which deviate from 180° unlike LIDAR applications. Instruments exploiting the difference in the P44/P11 ratio at a scattering angle around 115° are significantly constrained in distinguishing between water and ice because small droplets with size parameters between 5 and 10 do cause very high circular depolarizations at this angle. If the absence of the liquid phase is confirmed, the use of circular depolarization in single particle detection is more sensitive and less affected by particle orientation.

  19. A simple circular-polarized antenna: Circular waveguide horn coated with lossy magnetic material

    Science.gov (United States)

    Lee, Choon S.; Justice, D. W.; Lee, Shung-Wu

    1988-02-01

    It is shown that a circular waveguide horn coated with a lossy material in its interior wall can be used as an alternative to a corrugated waveguide for radiating a circularly polarized (CP) field. To achieve good CP radiation, the diameter of the structure must be larger than the free-space wavelength, and the coating material must be sufficiently lossy and magnetic. The device is cheaper and lighter in weight than the corrugated one.

  20. Collapse Behaviour and Energy Absorption of Aluminium Tubes Filled with Wood Sawdust

    Directory of Open Access Journals (Sweden)

    Raj Kiran

    2015-10-01

    Full Text Available Experiments on filled and empty circular thin walled Aluminium AA6063 tubes with varying L/D ratios have been performed to study load compression and energy absorbed for quasi static axial and oblique loading. Dependence of deformation characteristics and energy absorption responses have been studied. Energy absorption was measured from load-displacement graph obtained from UTM using MATLAB. Tubes were clamped at the lower end and axial and oblique loads were applied by applying a force at upper end with different angles to the centreline of column. Peak loads and absorbed energies have been compared for filled and empty tubes for same L/D ratio. Experimental results are used to determine energy absorption capacity due to plastic deformation of thin walled tube. The goal of the research was to study the interaction between the forming and crash response of Al AA6063 in order to evaluate its potential for use in vehicle design for crashworthiness.

  1. Steam generator tube integrity program

    Energy Technology Data Exchange (ETDEWEB)

    Dierks, D.R.; Shack, W.J. [Argonne National Laboratory, IL (United States); Muscara, J.

    1996-03-01

    A new research program on steam generator tubing degradation is being sponsored by the U.S. Nuclear Regulatory Commission (NRC) at Argonne National Laboratory. This program is intended to support a performance-based steam generator tube integrity rule. Critical areas addressed by the program include evaluation of the processes used for the in-service inspection of steam generator tubes and recommendations for improving the reliability and accuracy of inspections; validation and improvement of correlations for evaluating integrity and leakage of degraded steam generator tubes, and validation and improvement of correlations and models for predicting degradation in steam generator tubes as aging occurs. The studies will focus on mill-annealed Alloy 600 tubing, however, tests will also be performed on replacement materials such as thermally-treated Alloy 600 or 690. An overview of the technical work planned for the program is given.

  2. Sealed ion accelerator tubes (survey)

    International Nuclear Information System (INIS)

    The first publications on developing commercial models of small-scale sealed accelerator tubes in which neutrons are generated appeared in the foreign press in 1954 to 1957; they were very brief and were advertising-oriented. The tubes were designed for neutron logging of oil wells instead of ampule neutron sources (Po + Be, Ra + Be). Later, instruments of this type began to be called neutron tubes from the resulting neutron radiation that they gave off. In Soviet Union a neutron tube was developed in 1958 in connection with the development of the pulsed neutron-neutron method of studying the geological profile of oil wells. At that time the tube developed was intended, in the view of its inventors, to replace standard isotope sources with constant neutron yield. A fairly detailed survey of neutron tubes was made in the studies. 8 refs., 8 figs

  3. Job center

    Science.gov (United States)

    To better meet the needs of AGU members, a program has been started to increase the effectiveness of the Job Center activity at the Spring and Fall Meetings. As a result, participation in the Job Center at the 1988 AGU Spring Meeting in Baltimore increased substantially compared to previous Spring Meetings. The number of employers, applicants, and interviews scheduled more than doubled compared to the 1987 Spring Job Center.In order to make the meeting Job Centers even better, a survey is being conducted of employers and applicants who participated in the 1988 Spring Job Center. Evaluation of this survey will be useful in continuing increased participation in and the effectiveness of the Job Center at the 1988 Fall Meeting. Past participants and those interested in the future of the Job Center are encouraged to forward comments and suggestions to AGU, Member Programs Division, 2000 Florida Ave., N.W., Washington, DC 20009.

  4. Circular Economy Development Mode Based on System Theory

    Institute of Scientific and Technical Information of China (English)

    Xiao Huamao; Wang Fengqi

    2007-01-01

    The paper tries to explore circular economy from the viewpoint of the system theory.Circular economy is a kind of complicated economic acdvity,and it is a wholly new ecotype economy pmposed by Western countries after they had summed up many experiences and lessons from traditional economy.It is an entirety and has many layers.It keeps an open and dynamic balance.Because the system theory is the theoretical foundation of circular economy,we should systemically analyze and study circular economy from the macroscopic view,correctly grasp its operational laws,improve its service functions,and realize human beings's ustainable development.The paper introduces the content and general characteristics of the system theory and the idea of circular economy.Then it analyzes circular economy based on the systemtheory.The paper concludes that the intonation of circular economy and the system theory can promote the functions of circular economy.

  5. SOME RESULTS ON CIRCULAR PERFECT GRAPHS AND PERFECT GRAPHS

    Institute of Scientific and Technical Information of China (English)

    XU Baogang

    2005-01-01

    An r-circular coloring of a graph G is a map f from V(G) to the set of open unit intervals of an Euclidean circle of length r,such that f(u) ∩ f(v) = φ whenever uv ∈ E(G).Circular perfect graphs are defined analogously to perfect graphs by means of two parameters,the circular chromatic number and the circular clique number.In this paper,we study the properties of circular perfect graphs.We give (1) a necessary condition for a graph to be circular perfect,(2) some circular critical imperfect graphs,and (3) a characterization of graphs with the property that each of their induced subgraphs has circular clique number the same as its clique number,and then the two conjectures that are equivalent to the perfect graph conjecture.

  6. Influence of tube shape on falling water film thickness and Nusselt number outside horizontal tube%管形对水平管降膜圆周膜厚和Nusselt数的影响

    Institute of Scientific and Technical Information of China (English)

    罗林聪; 潘继红; 田茂诚; 黄涛; 任毓程

    2013-01-01

    针对海水淡化系统的水平管降膜蒸发,建立了二维数值模型,分析了光滑圆管和6种不同截面形状的蛋形管外降膜流动及传热特性.采用VOF方法考察了不同管型对管外液膜分布和传热特性的影响.数值结果表明:蛋形管外液体沿周向流动较圆管稍快,且可获得更均匀更薄的液膜;液膜厚度随半轴比e增大而减小,随周向先逐渐减小后迅速增加,圆管和蛋形管的液膜最小值分别出现在周向相对坐标0.69和0.70~0.84附近.蛋形管的膜内量纲1温度较圆管的小,其热边界层厚度较薄,具有更好的传热性能.拟合数据得到,e为2.4的蛋形管具有最好的传热性能,其Nusselt数可达0.32,较圆管的高出12.68%.最后,将数值模拟结果与文献中的数据进行了对比,验证了数值模型的可行性和合理性.%The flow and heat transfer characteristics of falling water film outside horizontal tubes in falling film evaporators in seawater desalination were investigated with two-dimensional numerical simulation.Two types of tubes,including a smooth circular tube and six oval-shaped tubes were employed in the simulation.The physical model and mathematical equations for the circular tube and oval-shaped tubes are represented separately.Volume of fluid method is employed to investigate the influence of sectional shape of tube on distribution of film thickness and heat transfer performance.The numerical results indicate that the flow velocity of falling film on the oval-shaped tubes is larger and the film around the oval-shaped tube is more uniform and thinner than that around the circular tube.The film thickness grows with increasing semi-axis ratio,ε,and decreases gradually at first and then increases rapidly along the circumference.The minimum value of the film thickness appears approximately at the circumferential dimensionless position of 0.69 and 0.70-0.84 for the smooth circular tube and oval-shaped tubes

  7. Alternate tube plugging criteria for steam generator tubes

    Energy Technology Data Exchange (ETDEWEB)

    Cueto-Felgueroso, C.; Aparicio, C.B. [Tecnatom, S.A., Madrid (Spain)

    1997-02-01

    The tubing of the Steam Generators constitutes more than half of the reactor coolant pressure boundary. Specific requirements governing the maintenance of steam generator tubes integrity are set in Plant Technical Specifications and in Section XI of the ASME Boiler and Pressure Vessel Code. The operating experience of Steam Generator tubes of PWR plants has shown the existence of some types of degradatory processes. Every one of these has an specific cause and affects one or more zones of the tubes. In the case of Spanish Power Plants, and depending on the particular Plant considered, they should be mentioned the Primary Water Stress Corrosion Cracking (PWSCC) at the roll transition zone (RTZ), the Outside Diameter Stress Corrosion Cracking (ODSCC) at the Tube Support Plate (TSP) intersections and the fretting with the Anti-Vibration Bars (AVBs) or with the Support Plates in the preheater zone. The In-Service Inspections by Eddy Currents constitutes the standard method for assuring the SG tubes integrity and they permit the monitoring of the defects during the service life of the plant. When the degradation reaches a determined limit, called the plugging limit, the SG tube must be either repaired or retired from service by plugging. Customarily, the plugging limit is related to the depth of the defect. Such depth is typically 40% of the wall thickness of the tube and is applicable to any type of defect in the tube. In its origin, that limit was established for tubes thinned by wastage, which was the predominant degradation in the seventies. The application of this criterion for axial crack-like defects, as, for instance, those due to PWSCC in the roll transition zone, has lead to an excessive and unnecessary number of tubes being plugged. This has lead to the development of defect specific plugging criteria. Examples of the application of such criteria are discussed in the article.

  8. Chirality and Circular Polarization in Models of Inflation

    CERN Document Server

    Alexander, Stephon; Sims, Robert

    2016-01-01

    We investigate the possibility that a chiral asymmetry during inflation can manifest as net circular polarization in photons. Using an example known to produce a helicity imbalance in fermions, we show that superhorizon photon modes produced during inflation acquire net circular polarization. Modes that reenter the horizon around last scattering can thermalize into the Cosmic Microwave Background while retaining a portion of their net circular polarization. We also consider the possibility of direct detection of the circular polarization in the CMB.

  9. Electron tubes for industrial applications

    Science.gov (United States)

    Gellert, Bernd

    1994-05-01

    This report reviews research and development efforts within the last years for vacuum electron tubes, in particular power grid tubes for industrial applications. Physical and chemical effects are discussed that determine the performance of todays devices. Due to the progress made in the fundamental understanding of materials and newly developed processes the reliability and reproducibility of power grid tubes could be improved considerably. Modern computer controlled manufacturing methods ensure a high reproducibility of production and continuous quality certification according to ISO 9001 guarantees future high quality standards. Some typical applications of these tubes are given as an example.

  10. Dermatology on YouTube

    OpenAIRE

    Boyers, Lindsay N.; Quest, Tyler; Karimkhani, Chante; Connett, Jessica; Dellavalle, Robert P.

    2014-01-01

    YouTube, reaches upwards of six billion users on a monthly basis and is a unique source of information distribution and communication. Although the influence of YouTube on personal health decision-making is well established, this study assessed the type of content and viewership on a broad scope of dermatology related content on YouTube. Select terms (i.e. dermatology, sun protection, skin cancer, skin cancer awareness, and skin conditions) were searched on YouTube. Overall, the results inclu...

  11. YouTube and 'psychiatry'.

    Science.gov (United States)

    Gordon, Robert; Miller, John; Collins, Noel

    2015-12-01

    YouTube is a video-sharing website that is increasingly used to share and disseminate health-related information, particularly among younger people. There are reports that social media sites, such as YouTube, are being used to communicate an anti-psychiatry message but this has never been confirmed in any published analysis of YouTube clip content. This descriptive study revealed that the representation of 'psychiatry' during summer 2012 was predominantly negative. A subsequent smaller re-analysis suggests that the negative portrayal of 'psychiatry' on YouTube is a stable phenomenon. The significance of this and how it could be addressed are discussed. PMID:26755987

  12. The Study of Heat Transfer on a Heated Circular Surface by an Impinging, Circular Water Jet with the Low Velocity Against the Direction of Gravity

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Tae; Eom, Yong Kyoon [Andong National University, Andong (Korea, Republic of)

    2009-12-15

    The heat transfer phenomenon was investigated on this study when a circular water jet with low velocity flows to the downward facing heated circular plate and against the direction of gravity. Data are presented for jet flow rate between 0.23 and 2.3 l/min, jet fluid temperature of 24 .deg. C, heat fluxes between 345 and 687 W/m{sup 2}, H/D=1, 2 and 3 with a single round jet diameter 2mm. The effects of heat flux, jet velocity and H/D on the local heat transfer are investigated in for the various regions of jet impingement. The local heat transfer distributions are analyzed based on the visualization of jet flow field. Data from experimental results are correlated by expressions of the from Nu = 0.01Re{sup 0.58} {center_dot} Pr{sup 0.4}.

  13. Learning from YouTube [Video Book

    Science.gov (United States)

    Juhasz, Alexandra

    2011-01-01

    YouTube is a mess. YouTube is for amateurs. YouTube dissolves the real. YouTube is host to inconceivable combos. YouTube is best for corporate-made community. YouTube is badly baked. These are a few of the things Media Studies professor Alexandra Juhasz (and her class) learned about YouTube when she set out to investigate what actually happens…

  14. Prediction of the mean folding force during the axial compression in foam-filled grooved tubes by theoretical analysis

    International Nuclear Information System (INIS)

    Highlights: ► This article studies folding process in foam-filled circular grooved tubes. ► Mean folding force in polyurethane foam-filled tubes is predicted, theoretically. ► Also, total absorbed energy per unit of tube length is calculated, theoretically. ► The specific absorbed energy by filled grooved tube is predicted, theoretically. ► Comparison of theoretical and experimental results shows a good correlation. -- Abstract: In this article, some theoretical relations are derived to predict the mean folding force, total absorbed energy per unit of tube length and specific absorbed energy per unit of total mass by the polyurethane foam-filled grooved tubes with circular cross section under the axial compression process. During the folding process, a new theoretical model of deformation is introduced for the polyurethane foam-filler. The theoretical analysis is developed on the basis of the energy method. Some foam-filled grooved specimens were prepared and axially compressed to obtain the experimental diagram of the folding force versus the axial displacement. Comparison of the theoretical predictions with the experimental results showed a good agreement. Then, by considering the interaction effect between the polyurethane foam and the inner wall of grooved tubes, a semi-empirical relation was derived. Predictions along with considering the interaction factor obtained from the semi-empirical relation indicate a better correlation with those of the experiments.

  15. Novel X band Compact Waveguide Dual Circular Polarizer

    CERN Document Server

    Xu, Chen; Wang, Juwen

    2014-01-01

    A novel type of dual circular polarizer is developed to convert the TE10 mode into two different polarization TE11 modes in a circular waveguide. This design consists two major parts: a TE10 to TE10/TE20 converter and an overmoded TE10/TE20 to circular TE11 modes converter.

  16. Photoinduced Circular Anisotropy in Side-Chain Azobenzene Polyesters

    DEFF Research Database (Denmark)

    Nikolova, L.; Todorov, T.; Ivanov, M.;

    1997-01-01

    We report for the first time the inducing of large circular anisotropy in previously unoriented films of side-chain azobenzene polyesters on illumination with circularly polarized light at a wavelength of 488 nm. The circular dichroism and optical activity are measured simultaneously in real time...

  17. DNA as a Model for Probing Polymer Entanglements: Circular Polymers and Non-Classical Dynamics

    Directory of Open Access Journals (Sweden)

    Kathryn Regan

    2016-09-01

    Full Text Available Double-stranded DNA offers a robust platform for investigating fundamental questions regarding the dynamics of entangled polymer solutions. The exceptional monodispersity and multiple naturally occurring topologies of DNA, as well as a wide range of tunable lengths and concentrations that encompass the entanglement regime, enable direct testing of molecular-level entanglement theories and corresponding scaling laws. DNA is also amenable to a wide range of techniques from passive to nonlinear measurements and from single-molecule to bulk macroscopic experiments. Over the past two decades, researchers have developed methods to directly visualize and manipulate single entangled DNA molecules in steady-state and stressed conditions using fluorescence microscopy, particle tracking and optical tweezers. Developments in microfluidics, microrheology and bulk rheology have also enabled characterization of the viscoelastic response of entangled DNA from molecular levels to macroscopic scales and over timescales that span from linear to nonlinear regimes. Experiments using DNA have uniquely elucidated the debated entanglement properties of circular polymers and blends of linear and circular polymers. Experiments have also revealed important lengthscale and timescale dependent entanglement dynamics not predicted by classical tube models, both validating and refuting new proposed extensions and alternatives to tube theory and motivating further theoretical work to describe the rich dynamics exhibited in entangled polymer systems.

  18. Design of circular differential microphone arrays

    CERN Document Server

    Benesty, Jacob; Cohen, Israel

    2015-01-01

    Recently, we proposed a completely novel and efficient way to design differential beamforming algorithms for linear microphone arrays. Thanks to this very flexible approach, any order of differential arrays can be designed. Moreover, they can be made robust against white noise amplification, which is the main inconvenience in these types of arrays. The other well-known problem with linear arrays is that electronic steering is not really feasible.  In this book, we extend all these fundamental ideas to circular microphone arrays and show that we can design small and compact differential arrays of any order that can be electronically steered in many different directions and offer a good degree of control of the white noise amplification problem, high directional gain, and frequency-independent response. We also present a number of practical examples, demonstrating that differential beamforming with circular microphone arrays is likely one of the best candidates for applications involving speech enhancement (i....

  19. Shock structure in non-circular jets

    Science.gov (United States)

    Morris, Philip J.; Bhat, Thonse R. S.

    1989-01-01

    The shock-cell structure of supersonic jets with non-circular exit geometry is modeled using a linearized analysis. The model takes into account the finite thickness of the jet shear layer using realistic velocity and density profiles. The effects of the shear layer turbulence are included by incorporating eddy-viscosity terms. A finite-difference numerical method is used to solve the steady linearized equations of motion. A body-fitted coordinate system is used to describe the shear layer. The variation of the pressure fluctuation with downstream distance is given for circular jets and for an elliptic jet of aspect ratio 2.0. Comparisons with experimental data are made. Difficulties with the numerical technique are also discussed.

  20. The Biogenesis of Nascent Circular RNAs

    Directory of Open Access Journals (Sweden)

    Yang Zhang

    2016-04-01

    Full Text Available Steady-state circular RNAs (circRNAs have been mapped to thousands of genomic loci in mammals. We studied circRNA processing using metabolic tagging of nascent RNAs with 4-thiouridine (4sU. Strikingly, the efficiency of circRNA processing from pre-mRNA is extremely low endogenously. Additional studies revealed that back-splicing outcomes correlate with fast RNA Polymerase II elongation rate and are tightly controlled by cis-elements in vivo. Additionally, prolonged 4sU labeling in cells shows that circRNAs are largely processed post-transcriptionally and that circRNAs are stable. Circular RNAs that are abundant at a steady-state level tend to accumulate. This is particularly true in cells, such as neurons, that have slow division rates. This study uncovers features of circRNA biogenesis by investigating the link between nascent circRNA processing and transcription.

  1. Circular machine design techniques and tools

    International Nuclear Information System (INIS)

    Some of the basic optics principles involved in the design of circular accelerators such as Alternating Gradient Synchrotrons, Storage and Collision Rings, and Pulse Stretcher Rings are outlined. Typical problems facing a designer are defined, and the main references and computational tools are reviewed that are presently available. Two particular classes of problems that occur typically in accelerator design are listed - global value problems, which affect the control of parameters which are characteristic of the complete closed circular machine, and local value problems. Basic mathematical formulae are given that are considered useful for a first draft of a design. The basic optics building blocks that can be used to formulate an initial machine design are introduced, giving only the elementary properties and transfer matrices only in one transverse plane. Solutions are presented for some first-order and second-order design problems

  2. Circular polarization sensitive absorbers based on graphene

    Science.gov (United States)

    Yang, Kunpeng; Wang, Min; Pu, Mingbo; Wu, Xiaoyu; Gao, Hui; Hu, Chenggang; Luo, Xiangang

    2016-01-01

    It is well known that the polarization of a linearly polarized (LP) light would rotate after passing through a single layer graphene under the bias of a perpendicular magnetostatic field. Here we show that a corresponding phase shift could be expected for circularly polarized (CP) light, which can be engineered to design the circular polarization sensitive devices. We theoretically validate that an ultrathin graphene-based absorber with the thickness about λ/76 can be obtained, which shows efficient absorption >90% within incident angles of ±80°. The angle-independent phase shift produced by the graphene is responsible for the nearly omnidirectional absorber. Furthermore, a broadband absorber in frequencies ranging from 2.343 to 5.885 THz with absorption over 90% is designed by engineering the dispersion of graphene. PMID:27034257

  3. Tangent hyperbolic circular frequency diverse array radars

    OpenAIRE

    Sarah Saeed; Ijaz Mansoor Qureshi; Waseem Khan; Ayesha Salman

    2016-01-01

    Frequency diverse array (FDA) with uniform frequency offset (UFO) has been in spot light of research for past few years. Not much attention has been devoted to non-UFOs in FDA. This study investigates tangent hyperbolic (TH) function for frequency offset selection scheme in circular FDAs (CFDAs). Investigation reveals a three-dimensional single-maximum beampattern, which promises to enhance system detection capability and signal-to-interference plus noise ratio. Furthermore, by utilising the ...

  4. Resonant Laser Cooling of Circular Accelerator Beams

    OpenAIRE

    Tumanian, R. V.

    2004-01-01

    The resonant laser cooling of circular accelerator beams of relativistic charged particle is studied. It is shown that in the approximation of the given external electromagnetic wave amplitude (small gain free electron laser) the emittance of a beam of charged particles decreases. In the field of particle energy about 100 in the mass energy units the beam energy losses are negligible. The discovered effect can be used for cooling of charged particle beams in various accelerators. The signific...

  5. Circular Proteins from Plants and Fungi*

    OpenAIRE

    Göransson, Ulf; Burman, Robert; Gunasekera, Sunithi; Strömstedt, Adam A.; Rosengren, K. Johan

    2012-01-01

    Circular proteins, defined as head-to-tail cyclized polypeptides originating from ribosomal synthesis, represent a novel class of natural products attracting increasing interest. From a scientific point of view, these compounds raise questions of where and why they occur in nature and how they are formed. From a rational point of view, these proteins and their structural concept may be exploited for crop protection and novel pharmaceuticals. Here, we review the current knowledge of three prot...

  6. SEAMLESS TECHNOLOGY ON CIRCULAR KNITTING MACHINES

    OpenAIRE

    CRETU Viorica

    2014-01-01

    With industrial progress, the advancements in garment manufacturing have evolved from cut & sew to complete garment knitting, which produces one entire garment without sewing or linking process. Seamless knitting technology is similar to sock manufacture, the specialized circular knitting machines producing 3 dimensional garments with no side seams, with the waistband integrated with body of the garment and with knitted washing instructions and logos. The paper starts by presenting the main a...

  7. FROM CIRCULAR ECONOMY TO BLUE ECONOMY

    OpenAIRE

    Iustin-Emanuel, ALEXANDRU; Alexandru, TASNADI

    2014-01-01

    Addressing the subject of this essay is based on the background ideas generated by a new branch of science - Biomimicry. According to European Commissioner for the Environment, "Nature is the perfect model of circular economy". Therefore, by imitating nature, we are witnessing a process of cycle redesign: production-consumption-recycling. The authors present some reflections on the European Commission's decision to adopt after July 1, 2014 new measures concerning the development of more circu...

  8. Circular symmetrization of condensers on Riemann surfaces

    Science.gov (United States)

    Dubinin, V. N.

    2015-01-01

    We give a simplified definition of the new version of circular symmetrization which has previously been suggested by the author for solving extremal problems in geometric function theory. A proof of the symmetrization principle for the capacities of condensers on Riemann surfaces is presented. In addition, the class of condensers under consideration is extended and all the cases of equality in the symmetrization principle are found. Bibliography: 22 titles.

  9. Gravitational collapse of a circularly symmetric star

    OpenAIRE

    Sharma, Ranjan; Das, Shyam; Rahaman, Farook; Shit, Gopal Chandra

    2015-01-01

    We investigate the collapse of a circularly symmetric star with outgoing radiation in ($2+1$)-dimensional anti-de Sitter spacetime. The exterior spacetime of the collapsing star is assumed to be described by the non-static generalization of the Ba\\~nados, Teitelboim and Zanelli [{\\em Phys. Rev. Lett.} {\\bf 69} (1992) 1849 ] metric. Making use of the junction conditions joining smoothly the interior and the exterior spacetimes across the boundary, we analyze the impacts of various factors on t...

  10. Introduction to transfer lines and circular machines

    International Nuclear Information System (INIS)

    This course was given in the 1983-84 Academic Training Programme. It is designed as an elementary introduction to both the theory and the hardware for transfer lines and circular machines. The course is limited to linear problems and treates the topics of single particle motion in the transverse and longitudinal planes, emittance ellipses, parameterisation, optical properties of some specific modules, stabilities in the transverse and longitudinal planes, field and gradient errors, and scattering in thin windows. (orig.)

  11. Circular Modes for Flat Beams in LHC

    CERN Document Server

    Burov, A

    2013-01-01

    Typically x/y optical coupling is considered as unwanted and thus suppressed--particular exclusions are electron and ionization coolers. Could some special coupled modes be effectively applied for the LHC complex? Apparently, the answer is positive: use of the circular modes in the injectors with their transformation into planar modes in the LHC allows both the space charge and beam-beam luminosity limitations to be significantly reduced, if not practically eliminated.

  12. Drops with non-circular footprints

    OpenAIRE

    Ravazzoli, Pablo D.; González, Alejandro G.; Diez, Javier A.

    2015-01-01

    In this paper we study the morphology of drops formed on partially wetting substrates, whose footprint is not circular. This type of drops is a consequence of the breakup processes occurring in thin films when anisotropic contact line motions take place. The anisotropy is basically due to hysteresis effects of the contact angle since some parts of the contact line are wetting, while others are dewetting. Here, we obtain a peculiar drop shape from the rupture of a long liquid filament sitting ...

  13. Circular Intensity Differential Scattering of chiral molecules

    Energy Technology Data Exchange (ETDEWEB)

    Bustamante, C.J.

    1980-12-01

    In this thesis a theory of the Circular Intensity Differential Scattering (CIDS) of chiral molecules as modelled by a helix oriented with respect to the direction of incidence of light is presented. It is shown that a necessary condition for the existence of CIDS is the presence of an asymmetric polarizability in the scatterer. The polarizability of the scatterer is assumed generally complex, so that both refractive and absorptive phenomena are taken into account.

  14. Broadband circularly polarized antennas for UHF SATCOM

    OpenAIRE

    Tekin, İbrahim; Tekin, Ibrahim; Manzhura, Oksana; Niver, Edip

    2011-01-01

    Novel circularly polarized (CP) antenna configurations derived from Moxon type antenna (bent dipole element over a ground plane) for broadband VHF SATCOM applications. A sequence of topologies starting from a single vertical element to two vertical elements of the Moxon arms, then widened strip arm elements were studied. Further, arms were widened to bow tie structures with bents at 900.for achieving broadband operation. Bow tie elements were further split and optimized at a certain angle to...

  15. Covalently closed circular deoxyribonucleic acids in spiroplasmas.

    OpenAIRE

    Ranhand, J M; Mitchell, W. O.; Popkin, T J; Cole, R. M.

    1980-01-01

    Ten of twelve spiroplasma strains from different sources carried multiple covalently closed circular duplex deoxyribonucleic acid molecules, as shown by ethidium bromide-cesium chloride gradient centrifugation of cell lysates and examination of resulting bands by electron microscopy and agarose gel electrophoresis. Two to eight size classes per strain, comprising molecules of masses from 1 X 10(6) to 26 X 10(6), were detected. Several size classes of molecules were found in common in differen...

  16. Nondestructive test of brazed cooling tubes of prototype bolometer camera housing using active infrared thermography.

    Science.gov (United States)

    Tahiliani, Kumudni; Pandya, Santosh P; Pandya, Shwetang; Jha, Ratneshwar; Govindarajan, J

    2011-01-01

    The active infrared thermography technique is used for assessing the brazing quality of an actively cooled bolometer camera housing developed for steady state superconducting tokamak. The housing is a circular pipe, which has circular tubes vacuum brazed on the periphery. A unique method was adopted to monitor the temperature distribution on the internal surface of the pipe. A stainless steel mirror was placed inside the pipe and the reflected IR radiations were viewed using an IR camera. The heat stimulus was given by passing hot water through the tubes and the temperature distribution was monitored during the transient phase. The thermographs showed a significant nonuniformity in the brazing with a contact area of around 51%. The thermography results were compared with the x-ray radiographs and a good match between the two was observed. Benefits of thermography over x-ray radiography testing are emphasized. PMID:21280850

  17. Nasogastric tube syndrome induced by an indwelling long intestinal tube.

    Science.gov (United States)

    Sano, Naoki; Yamamoto, Masayoshi; Nagai, Kentaro; Yamada, Keiichi; Ohkohchi, Nobuhiro

    2016-04-21

    The nasogastric tube (NGT) has become a frequently used device to alleviate gastrointestinal symptoms. Nasogastric tube syndrome (NTS) is an uncommon but potentially life-threatening complication of an indwelling NGT. NTS is characterized by acute upper airway obstruction due to bilateral vocal cord paralysis. We report a case of a 76-year-old man with NTS, induced by an indwelling long intestinal tube. He was admitted to our hospital for treatment of sigmoid colon cancer. He underwent sigmoidectomy to release a bowel obstruction, and had a long intestinal tube inserted to decompress the intestinal tract. He presented acute dyspnea following prolonged intestinal intubation, and bronchoscopy showed bilateral vocal cord paralysis. The NGT was removed immediately, and tracheotomy was performed. The patient was finally discharged in a fully recovered state. NTS be considered in patients complaining of acute upper airway obstruction, not only with a NGT inserted but also with a long intestinal tube. PMID:27099450

  18. Explosive welding of a tube into a tube sheet

    Science.gov (United States)

    Green, Sheryll C.; Linse, Vonne D.

    1978-10-03

    A cartridge containing an explosive charge is placed within a tube assembled within a tube sheet. The charge is detonated through use of a detonator cord containing a minimum but effective amount of explosive material. The cord is contained inside a tubular shield throughout most of its length within the cartridge. A small length of the cord extends beyond the tubular shield to contact and detonate the explosive charge in its rear portion near the cartridge base. The cartridge base is provided of substantial mass and thickness in respect to side and front walls of the cartridge to minimize bulging beyond the rear face of the tube sheet. For remote activation an electrically activated detonator of higher charge density than the cord is attached to the cord at a location spaced from the tube sheet, cartridge and tube.

  19. FROM CIRCULAR ECONOMY TO BLUE ECONOMY

    Directory of Open Access Journals (Sweden)

    Iustin-Emanuel, ALEXANDRU

    2014-11-01

    Full Text Available Addressing the subject of this essay is based on the background ideas generated by a new branch of science - Biomimicry. According to European Commissioner for the Environment, "Nature is the perfect model of circular economy". Therefore, by imitating nature, we are witnessing a process of cycle redesign: production-consumption-recycling. The authors present some reflections on the European Commission's decision to adopt after July 1, 2014 new measures concerning the development of more circular economies. Starting from the principles of Ecolonomy, which is based on the whole living paradigm, this paper argues for the development within each economy of entrepreneurial policies related to the Blue economy. In its turn, Blue economy is based on scientific analyses that identify the best solutions in a business. Thus, formation of social capital will lead to healthier and cheaper products, which will stimulate entrepreneurship. Blue economy is another way of thinking economic practice and is a new model of business design. It is a healthy, sustainable business, designed for people. In fact, it is the core of the whole living paradigm through which, towards 2020, circular economy will grow more and more.

  20. Continuous-wave circular polarization terahertz imaging

    Science.gov (United States)

    Martin, Jillian P.; Joseph, Cecil S.; Giles, Robert H.

    2016-07-01

    Biomedical applications of terahertz (THz) radiation are appealing because THz radiation is nonionizing and has the demonstrated ability to detect intrinsic contrasts between cancerous and normal tissue. A linear polarization-sensitive detection technique for tumor margin delineation has already been demonstrated; however, utilization of a circular polarization-sensitive detection technique has yet to be explored at THz frequencies. A reflective, continuous-wave THz imaging system capable of illuminating a target sample at 584 GHz with either linearly or circularly polarized radiation, and capable of collecting both cross- and copolarized signals remitted from the target, is implemented. To demonstrate the system's utility, a fresh ex vivo human skin tissue specimen containing nonmelanoma skin cancer was imaged. Both polarization-sensitive detection techniques showed contrast between tumor and normal skin tissue, although some differences in images were observed between the two techniques. Our results indicate that further investigation is required to explain the contrast mechanism, as well as to quantify the specificity and sensitivity of the circular polarization-sensitive detection technique.

  1. Pulsed Accretion onto Eccentric and Circular Binaries

    CERN Document Server

    Muñoz, Diego J

    2016-01-01

    We present numerical simulations of circumbinary accretion onto eccentric and circular binaries using the moving-mesh code AREPO. This is the first set of simulations to tackle the problem of binary accretion using a finite-volume scheme on a freely moving mesh, which allows for accurate measurements of accretion onto individual stars for arbitrary binary eccentricity. While accretion onto a circular binary shows bursts with period of ~5 times the binary period P_b,accretion onto an eccentric binary is predominantly modulated at the period ~1P_b. For an equal-mass circular binary, the accretion rates onto individual stars are quite similar to each other, following the same variable pattern in time. By contrast, for eccentric binaries, one of the stars can accrete at a rate 10-20 times larger than its companion. This "symmetry breaking" between the stars, however, alternates over timescales of order 200 P_b, and can be attributed to a slowly precessing, eccentric circumbinary disk. Over longer timescales, the ...

  2. Application of circular polarized synchrotron radiation

    International Nuclear Information System (INIS)

    The idea of using the polarizing property of light for physical experiment by controlling it variously has been known from old time, and the Faraday effect and the research by polarizing microscopy are its examples. The light emitted from the electron orbit of an accelerator has the different polarizing characteristics from those of the light of a laboratory light source, and as far as observing it within the electron orbit plane, it becomes linearly polarized light. By utilizing this property well, research is carried out at present in synchrotron experimental facilities. Recently, the technology related to the insert type light cources using permanent magnets has advanced remarkably, and circular polarized light has become to be producible. If the light like this can be obtained with the energy not only in far ultraviolet region but also to x-ray region at high luminance, new possibility should open. At the stage that the design of an insert type light source was finished, and its manufacture was started, the research on the method of evaluating the degree of circular polarization and the research on the utilization of circular polarized synchrotron radiation are earnestly carried out. In this report, the results of researches presented at the study meeting are summarized. Moreover, the design and manufacture of the beam lines for exclusive use will be carried out. (Kako, I.)

  3. Jose Cabrera (Zorita) tube examination

    International Nuclear Information System (INIS)

    Jose Cabrera (Zorita) tube examination procedures are discussed. This plant continues to use phosphate water chemistry (sodium/phosphate ratio = 2.1). Three hot leg tube segments were pulled from the Jose Cabera (Zorita) plant in 1985. One tube had a field EC indication on the OD at the first tube support plate and the other two had field EC indications on their ID about 3 inches above the bottom of the tube sheet. All three tubes were initially sent to Battelle for preliminary NDE and decontamination. Segments of two tubes were sent to Westinghouse for destructive examination. The results of the laboratory eddy current and radiographic examinations are given. The results of the visual examinations are also given. The tube with OD indications was destructively examined and shallow intergranular pitting and intergranular attack, up to 2 mils deep, were found on the OD in the tube sheet region. Local areas of IGA, up to 5 mils deep, were found on the OD within the tube support plate region. A summary of this information together with supporting micrographs is given. It was hypothesized that a caustic crevice environment was the cause of this mild degradation. Shallow areas of thinning or wastage, up to 3 mils, were found just above the top of the tube sheet in the sludge pile region. Even more shallow wastage was found at the edges of support plate locations. This wastage is believed to be the remnant of early plant chemistry when a higher sodium/phosphate ratio and higher phosphate concentration were allowed

  4. Piezoelectric Rotary Tube Motor

    Science.gov (United States)

    Fisher, Charles D.; Badescu, Mircea; Braun, David F.; Culhane, Robert

    2011-01-01

    A custom rotary SQUIGGLE(Registered TradeMark) motor has been developed that sets new benchmarks for small motor size, high position resolution, and high torque without gear reduction. Its capabilities cannot be achieved with conventional electromagnetic motors. It consists of piezoelectric plates mounted on a square flexible tube. The plates are actuated via voltage waveforms 90 out of phase at the resonant frequency of the device to create rotary motion. The motors were incorporated into a two-axis postioner that was designed for fiber-fed spectroscopy for ground-based and space-based projects. The positioner enables large-scale celestial object surveys to take place in a practical amount of time.

  5. Chapter 11. Digestive tube

    International Nuclear Information System (INIS)

    Exploration of the digestive tube by radioactive tracers relates mainly to the functional study of certain digestion or absorption troubles. The tracer absorbed by the digestibe system was followed by counting of the stools, successive measurements of the plasma radioactivity, measurements of urinary elimination or uptake on a storage organ such as the liver in the case of vitamin B12, measurement of whole-body radioactivity for vitamin B12 and iron. The different isotopic techniques used to study intestinal absorption of lipids, proteins and aminoacids, vitamin B 12 and iron were described and their contribution to the detection of exudative enteropathies and digestive haemorrhage was shown. It was pointed out that the stomach is one of the organs most accessible to standard exploration techniques. The role of sup(99m)Tc in both the morphological exploration of stomach and the study of gastric secretion, of 51Cr and 129Cs in the study of gastric evacuation were demonstrated

  6. RWGSCAT/CWGSCAT - RECTANGULAR AND CIRCULAR WAVEGUIDE JUNCTION SCATTERING PACKAGE

    Science.gov (United States)

    Hoppe, D. J.

    1994-01-01

    Accurate computer modeling of passive circular or rectangular waveguide components is often required during the design phase for optimizing frequency response and/or determining the tolerance required on components in order to meet radio frequency specifications. RWGSCAT/CWGSCAT is capable of modeling both types of waveguide components. The Scattering Matrix Program for Circular Waveguide Junctions, CWGSCAT, computes the scattering matrix for a circular waveguide. This includes a dual mode horn and certain types of corrugated horns. RWGSCAT, Rectangular WaveGuide junction SCATtering program, solves for the scattering properties of a rectangular waveguide device, such as a smooth or corrugated rectangular horn, step transformer, or filter. RWGSCAT and CWGSCAT are also available separately as NPO-19091 and NPO-18708, respectively. Many circular waveguide devices can be represented either exactly or approximately as a series of circular waveguide sections which have a common center. In addition, smooth tapers and horns of arbitrary profile may be approximated by a series of small steps. Devices that may be analyzed in this fashion include a simple waveguide step discontinuity, such as that used in a dual mode horn, a stepped matching section, or a corrugated waveguide section with constant varying slot depth. CWGSCAT will accurately predict the reflection and transmission characteristics of such devices, taking into account higher order mode excitation if it occurs as well as multiple reflections and stored energy at each discontinuity. For large devices, with respect to a wavelength where many modes may propagate, the reflection and transmission properties may be required for a higher order mode or series of modes exciting the device. Such interactions are represented best by defining a scattering matrix for the device. The matrix can be determined by using mode matching at each discontinuity present. The results for individual discontinuities are then cascaded to

  7. Functional Centering

    CERN Document Server

    Hahn, M

    1996-01-01

    Based on empirical evidence from a free word order language (German) we propose a fundamental revision of the principles guiding the ordering of discourse entities in the forward-looking centers within the centering model. We claim that grammatical role criteria should be replaced by indicators of the functional information structure of the utterances, i.e., the distinction between context-bound and unbound discourse elements. This claim is backed up by an empirical evaluation of functional centering.

  8. Plane Wall Effect of Flow around Two Circular Cylinders in Tandem Arrangement

    OpenAIRE

    Triyogi Yuwono,; Wawan Aries Widodo; Heru Mirmanto; Fahmi Fahreza

    2011-01-01

    The flow characteristic around two circular cylinders in tandem arrangement located near a plane wall were investigated experimentally in a uniform flow at a Reynolds Number of 5.3 x 104. The center to center spacing between the two cylinders relative to the cylinder diameter was constantly maintained at P/D = 1.5. The pressure distributions along the surface of the cylinder and the plane wall were measured by varying the gap-to-diameter of cylinder ratio (G/D) in the range of 0 < G/D < 0.467...

  9. Numerical simulation of cross-flow in a bank of tubes with three rows in the subcritical region of Reynolds

    International Nuclear Information System (INIS)

    The present work focused on 2-dimensional unsteady numerical simulation in predicting hydrodynamics and thermal characteristics of air flow across circular tube banks with integral wake splitters. The tube banks studied consist of three rows of tubes in staggered arrangement. The lengths of the splitter are 0, 0.5, 1.0, 1.5 and 2.0 times the tube diameter. The range of Reynolds number investigated is in the range of 1000 to 10000, which is in the sub-critical region of Reynolds number. The flow condition within this range is incompressible since the maximum Mach number is less than 0.3. The numerical approach was validated against the experimental works of Zukauskas (1985) and Anderson (1997). Local pressure coefficient for flow around a single tube with integral wake splitter is also presented for comparison. It was found that the present of the wake splitters was able to improve the overall heat transfer of the system

  10. Numerical simulation of cross-flow in a bank of tubes with three rows in the subcritical region of Reynolds

    Science.gov (United States)

    Suzairin; Faizal, Mohd; Raghavan, V. R.; Ambri, Zainal

    2013-12-01

    The present work focused on 2-dimensional unsteady numerical simulation in predicting hydrodynamics and thermal characteristics of air flow across circular tube banks with integral wake splitters. The tube banks studied consist of three rows of tubes in staggered arrangement. The lengths of the splitter are 0, 0.5, 1.0, 1.5 and 2.0 times the tube diameter. The range of Reynolds number investigated is in the range of 1000 to 10000, which is in the sub-critical region of Reynolds number. The flow condition within this range is incompressible since the maximum Mach number is less than 0.3. The numerical approach was validated against the experimental works of Zukauskas (1985) and Anderson (1997). Local pressure coefficient for flow around a single tube with integral wake splitter is also presented for comparison. It was found that the present of the wake splitters was able to improve the overall heat transfer of the system.

  11. Architectural Surfaces and Structures from Circular Arcs

    KAUST Repository

    Shi, Ling

    2013-12-01

    In recent decades, the popularity of freeform shapes in contemporary architecture poses new challenges to digital design. One of them is the process of rationalization, i.e. to make freeform skins or structures affordable to manufacture, which draws the most attention from geometry researchers. In this thesis, we aim to realize this process with simple geometric primitives, circular arcs. We investigate architectural surfaces and structures consisting of circular arcs. Our focus is lying on how to employ them nicely and repetitively in architectural design, in order to decrease the cost in manufacturing. Firstly, we study Darboux cyclides, which are algebraic surfaces of order ≤ 4. We provide a computational tool to identify all families of circles on a given cyclide based on the spherical model of M ̈obius geometry. Practical ways to design cyclide patches that pass through certain inputs are presented. In particular, certain triples of circle families on Darboux cyclides may be suitably arranged as 3-webs. We provide a complete classification of all possible 3-webs of circles on Darboux cyclides. We then investigate the circular arc snakes, which are smooth sequences of circu- lar arcs. We evolve the snakes such that their curvature, as a function of arc length, remains unchanged. The evolution of snakes is utilized to approximate given surfaces by circular arcs or to generated freeform shapes, and it is realized by a 2-step pro- cess. More interestingly, certain 6-arc snake with boundary constraints can produce a smooth self motion, which can be employed to build flexible structures. Another challenging topic is approximating smooth freeform skins with simple panels. We contribute to this problem area by approximating a negatively-curved 5 surface with a smooth union of rational bilinear patches. We provide a proof for vertex consistency of hyperbolic nets using the CAGD approach of the rational B ́ezier form. Moreover, we use Darboux transformations for the

  12. Background, Pattern and Policy of China for Developing Circular Economy

    Institute of Scientific and Technical Information of China (English)

    Zhu Dajian

    2008-01-01

    Circular economy has become one of China's important strategies to realize scientific development and build ecological civilization at present. As in China circular economy was put forward as a new economic pattern, the international community generally holds that this is an innovative move for China's economy to realize leap-forward development and hopes to learn more about the theory, policy and practice relating to China's circular economy. This article introduces and comments on the necessity to develop circular economy in China, implications and characteristics of China's circular economy, and China's main practices and policies to promote it at present.

  13. Measurement of heat transfer coefficient in the transition region of tube flow

    International Nuclear Information System (INIS)

    Heat transfer coefficient and friction factor were obtained experimentally for a circular tube in the transition region from the laminar to the turbulent flow. The measurements were made for two different kinds of intermittently turbulent regions; i.e., puff and slug. A relation between the heat transfer coefficient and the intermittency was examined. Variation of gas temperature was observed and found to be also intermittent. (author)

  14. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... Vision Research & Ophthalmology (DIVRO) Student Training Programs NEI Home About NEI Health Information News and Events Grants ... Research at NEI Education Programs Training and Jobs Home > NEI YouTube Videos > NEI YouTube Videos: Amblyopia NEI ...

  15. Gastrostomy feeding tube - pump - child

    Science.gov (United States)

    Feeding - gastrostomy tube - pump; G-tube - pump; Gastrostomy button - pump; Bard Button - pump; MIC-KEY - pump ... Gather supplies: Feeding pump (electronic or battery powered) Feeding set that matches the feeding pump (includes a feeding bag, drip chamber, roller clamp, ...

  16. Flaming on YouTube

    NARCIS (Netherlands)

    Moor, Peter J.; Heuvelman, Ard; Verleur, Ria

    2010-01-01

    In this explorative study, flaming on YouTube was studied using surveys of YouTube users. Flaming is defined as displaying hostility by insulting, swearing or using otherwise offensive language. Three general conclusions were drawn. First, although many users said that they themselves do not flame,

  17. Characterization of tube support alloys

    International Nuclear Information System (INIS)

    The involvement and relationship of carbon steel corrosion products in the tube denting phenomenon promoted an intensive research effort to: 1) understand, reproduce, and arrest the denting process, and 2) evaluate alternative tube support materials to provide additional corrosion resistance. The paper summarizes a corrosion testing program for the verification of type 405 stainless steel under acid or all volatile treatment conditions

  18. Circular hydraulic jump on finite surfaces with capillary limit

    Science.gov (United States)

    Mohajer, Behzad; Li, Ri

    2015-11-01

    A round liquid jet impinging on a circular disc with free edge generates a thin liquid film in the center surrounded by a thick film. For low flow rates, the thick film is bounded by a stable rim around the disc edge and flows off only from one spot at the edge. The outer Froude number remains constant for varied flow rates and disc sizes but changes with the surface tension of the fluid. The jump radius increases linearly with the flow rate, and the linear slope varies with the surface tension. Due to the stable-rim edge condition, the constant outer Froude numbers observed in our study are different from the constant value reported by Duchesne et al. ["Constant Froude number in a circular hydraulic jump and its implication on the jump radius selection," Europhys. Lett. 107, 54002 (2014)]. Despite the constant outer Froude numbers being independent of the flow rate, the inner Froude number changes with the flow rate, which is due to the surface tension force at the jump location. Force analysis is conducted by taking into account the stable rim, and the derived equations provide the relationship of jump radius with the contact angle of the stable rim, disc size, and jet flow. The maximum outer Froude number and the minimum inner Froude number are theoretically analyzed. Depending on the pre-jump velocity profile and the surface tension force at the jump, the maximum outer Froude number could be larger than unity. The shape of free surface at the jump is analyzed to evaluate the theoretical assumption of steep jump.

  19. 'Inca City' is Part of a Circular Feature

    Science.gov (United States)

    2002-01-01

    MGS MOC Release No. MOC2-319, 8 August 2002 [figure removed for brevity, see original site] 'Inca City' is the informal name given by Mariner 9 scientists in 1972 to a set of intersecting, rectilinear ridges that are located among the layered materials of the south polar region of Mars. Their origin has never been understood; most investigators thought they might be sand dunes, either modern dunes or, more likely, dunes that were buried, hardened, then exhumed. Others considered them to be dikes formed by injection of molten rock (magma) or soft sediment into subsurface cracks that subsequently hardened and then were exposed at the surface by wind erosion. The Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) has provided new information about the 'Inca City' ridges, though the camera's images still do not solve the mystery. The new information comes in the form of a MOC red wide angle context frame taken in mid-southern spring, shown above left and above right. The original Mariner 9 view of the ridges is seen at the center. The MOC image shows that the 'Inca City' ridges, located at 82oS, 67oW, are part of a larger circular structure that is about 86 km (53 mi) across. It is possible that this pattern reflects an origin related to an ancient, eroded meteor impact crater that was filled-in, buried, then partially exhumed. In this case, the ridges might be the remains of filled-in fractures in the bedrock into which the crater formed, or filled-in cracks within the material that filled the crater. Or both explanations could be wrong. While the new MOC image shows that 'Inca City' has a larger context as part of a circular form, it does not reveal the exact origin of these striking and unusual martian landforms.

  20. Bilamellar type streak tube design

    International Nuclear Information System (INIS)

    In ICF experiments, high dynamic range, high temporal and spatial resolution X-ray streak camera is a necessary diagnosis tool. To meet this requirement, a streak tube which uses bilamellar electrode lens and quadrupolar lens to focus electrons has been designed. This tube uses different ways to focus electrons in temporal axis and spatial axis. In temporal axis, it uses two effectively. The spatial resolution of this tube reaches 40 lp/mm even at the edge of photocathode, the temporal resolution is about 10 ps and the effective length of photocathode is 20 mm. Using different focusing ways in temporal and spatial directions, the tube will not focus electrons to a small spot, compared with conventional rotary and symmetric tubes, and thus its space charge effect is much weaker, and dynamic range is much larger. (authors)

  1. The rotating tubing hanger system

    International Nuclear Information System (INIS)

    Beam pump systems are among the most cost efficient artificial lift systems in the industry, assuming a long run time between pulling jobs to repair tubing failures caused by rod wear. The tubing string represents the second largest investment in the well. The longer the period of time the well can be kept on-line and producing between pulling jobs, the more efficient and cost effective is the beam pump system. This paper describes in detail the conception, development and implementation of a new system that extends tubing life on rod pumped wells. The system uses a very simple concept; rotate the tubing string to extend the length of time between tubing failures and the resultant pulling jobs. The system is powered directly from the walking beam and requires no additional power source; nor does the system use any additional energy

  2. Development of database on circular abandoned channel in Japan

    International Nuclear Information System (INIS)

    To develop a method for estimating late Quaternary uplift rates of inland mountainous terrains where fluvial terraces are poorly developed, we focused on 'circular abandoned channels', formed by meander cut-offs or river capture of an incised meandering river. We studied about 1,000 circular abandoned channels distributed throughout the Islands of Japan, and developed GIS database on circular abandoned channel in Japan. This database contains formation process, relative heights, degree of dissection and bedrocks of circular abandoned channels. Circular abandoned channels are distributed in inland mountainous terrains, where late Quaternary uplift rates are unknown, and indicate different relative heights along the same river. Relative heights tend to correlate with degree of dissection of the circular abandoned channels, which may indicate that degree of dissection correlate with ages of abandonment of circular abandoned channels. A CD-ROM is attached as an appendix. (J.P.N.)

  3. Nanoconfined circular and linear DNA - equilibrium conformations and unfolding kinetics

    CERN Document Server

    Alizadehheidari, M; Noble, C; Reiter-Schad, M; Nyberg, L K; Fritzsche, J; Mehlig, B; Tegenfeldt, J O; Ambjörnsson, T; Persson, F; Westerlund, F

    2016-01-01

    Studies of circular DNA confined to nanofluidic channels are relevant both from a fundamental polymer-physics perspective and due to the importance of circular DNA molecules in vivo. We here observe the unfolding of DNA from the circular to linear configuration as a light-induced double strand break occurs, characterize the dynamics, and compare the equilibrium conformational statistics of linear and circular configurations. This is important because it allows us to determine to which extent existing statistical theories describe the extension of confined circular DNA. We find that the ratio of the extensions of confined linear and circular DNA configurations increases as the buffer concentration decreases. The experimental results fall between theoretical predictions for the extended de Gennes regime at weaker confinement and the Odijk regime at stronger confinement. We show that it is possible to directly distinguish between circular and linear DNA molecules by measuring the emission intensity from the DNA....

  4. Distribution center

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    Distribution center is a logistics link fulfill physical distribution as its main functionGenerally speaking, it's a large and hiahly automated center destined to receive goods from various plants and suppliers,take orders,fill them efficiently,and deliver goods to customers as quickly as possible.

  5. HF electronic tubes. Technologies, grid tubes and klystrons

    International Nuclear Information System (INIS)

    This article gives an overview of the basic technologies of electronic tubes: cathodes, electronic optics, vacuum and high voltage. Then the grid tubes, klystrons and inductive output tubes (IOT) are introduced. Content: 1 - context and classification; 2 - electronic tube technologies: cathodes, electronic optics, magnetic confinement (linear tubes), periodic permanent magnet (PPM) focussing, collectors, depressed collectors; 3 - vacuum technologies: vacuum quality, surface effects and interaction with electrostatic and RF fields, secondary emission, multipactor effect, thermo-electronic emission; 4 - grid tubes: operation of a triode, tetrodes, dynamic operation and classes of use, 'common grid' and 'common cathode' operation, ranges of utilisation and limitations, operation of a tetrode on unadjusted load, lifetime of a tetrode, uses of grid tubes; 5 - klystrons: operation, impact of space charge, multi-cavity klystrons, interaction efficiency, extended interaction klystrons, relation between interaction efficiency, perveance and efficiency, ranges of utilization and power limitations, multi-beam klystrons and sheet beam klystrons, operation on unadjusted load, klystron band pass and lifetime, uses; 6 - IOT: principle of operation, ranges of utilisation and limitations, interaction efficiency and depressed collector IOT, IOT lifetime and uses. (J.S.)

  6. Magnetic Heat Transfer Enhancements on Fin-Tube Heat Exchangers

    Institute of Scientific and Technical Information of China (English)

    Yan SU; C.T. HSU

    2007-01-01

    通过DNS方法解耦合的三维非稳态流动和固流体能量方程组,本文研究了两平行磁质平板和圆管所组成的肋片式圆管换热器单元与震荡流体间的传热过程.对不同的磁场频率和振幅的三维动态流热场的模拟结果表明增强磁场频率和振幅能很有效地增加周期平均传热强度达到强化传热的目的.%Two narrowly-gapped magnetic parallel plates embedding a circular disk was considered as a unit-cell to represent the fin-tube heat exchanger where heat from a circular tube was dissipated by a series of parallel equally-spaced thin plates in normal to the tube. The unsteady 3-D continuity,Navier-Stokes and energy equations for fluids and solids describing the convective heat transfer for the unit-cell geometry were solved numerically with DNS method. The present study aims on using oscillating flows and magnetic fields to enhance the heat transfer for various amplitudes and frequencies of the magnetic field. Results from cycle-averaged heat fluxes from the cylinder wall show that the increase in magnetic amplitude and frequency will greatly enhance the heat transfer. The effects of the oscillating magnetic field were discussed and the three dimensional flow and temperature fields were also presented.

  7. [Isolated torsion of the fallopian tube: about two cases].

    Science.gov (United States)

    Bouguern, H; Bouchikhi, C; Chaara, H; Melhouf, M A; Banani, A

    2008-02-01

    Isolated torsion of the fallopian tube is extremely rare and difficult to diagnose, requires a coelioscopy, or a laparotomy in centers which do not have coelioscpie; often carried out too tardily, to allow the conservation of the horn. We report two observations of isolated torsion of the fallopian tube and we recall through the two clinical cases the diagnostic difficulties, the useful complementary examinations, the treatment and the causes of this pathology which must be systematically evoked in front of any acute abdominal syndrome in order to hope for an early surgical treatment and if possible conservative. PMID:18372548

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

    Science.gov (United States)

    Ciccarelli, G.; Cross, M.

    2016-06-01

    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. Computational simulations of hydrogen circular migration in protonated acetylene induced by circularly polarized light.

    Science.gov (United States)

    Shi, Xuetao; Li, Wen; Schlegel, H Bernhard

    2016-08-28

    The hydrogens in protonated acetylene are very mobile and can easily migrate around the C2 core by moving between classical and non-classical structures of the cation. The lowest energy structure is the T-shaped, non-classical cation with a hydrogen bridging the two carbons. Conversion to the classical H2CCH(+) ion requires only 4 kcal/mol. The effect of circularly polarized light on the migration of hydrogens in oriented C2H3 (+) has been simulated by Born-Oppenheimer molecular dynamics. Classical trajectory calculations were carried out with the M062X/6-311+G(3df,2pd) level of theory using linearly and circularly polarized 32 cycle 7 μm cosine squared pulses with peak intensity of 5.6 × 10(13) W/cm(2) and 3.15 × 10(13) W/cm(2), respectively. These linearly and circularly polarized pulses transfer similar amounts of energy and total angular momentum to C2H3 (+). The average angular momentum vectors of the three hydrogens show opposite directions of rotation for right and left circularly polarized light, but no directional preference for linearly polarized light. This difference results in an appreciable amount of angular displacement of the three hydrogens relative to the C2 core for circularly polarized light, but only an insignificant amount for linearly polarized light. Over the course of the simulation with circularly polarized light, this corresponds to a propeller-like motion of the three hydrogens around the C2 core of protonated acetylene. PMID:27586924

  10. Conditioning and breakdown phenomena in accelerator tubes

    International Nuclear Information System (INIS)

    Important breakdown mechanisms in accelerator tubes are reviewed, and discharge phenomena in NEC tubes are deduced from the surface appearance of the electrodes and insulators of a used tube. Microphotos of these surfaces are shown

  11. Eddy current signal comparison for tube identification

    Science.gov (United States)

    Glass, S. W.; Vojvodic, R.

    2015-03-01

    Inspection of nuclear power plant steam generator tubes is required to justify continued safe plant operation. The steam generators consist of thousands of tubes with nominal diameters of 15 to 22mm, approximately 1mm wall thickness, and 20 to 30m in length. The tubes are inspected by passing an eddy current probe through the tubes from tube end to tube end. It is critical to know exactly which tube identification (row and column) is associated with each tube's data. This is controlled by a precision manipulator that provides the tube ID to the eddy current system. Historically there have been some instances where the manipulator incorrectly reported the tube ID. This can have serious consequences including lack of inspection of a tube, or if a pluggable indication is detected, the tube is likely to be mis-plugged thereby risking a primary to secondary leak.

  12. Eddy current signal comparison for tube identification

    International Nuclear Information System (INIS)

    Inspection of nuclear power plant steam generator tubes is required to justify continued safe plant operation. The steam generators consist of thousands of tubes with nominal diameters of 15 to 22mm, approximately 1mm wall thickness, and 20 to 30m in length. The tubes are inspected by passing an eddy current probe through the tubes from tube end to tube end. It is critical to know exactly which tube identification (row and column) is associated with each tube's data. This is controlled by a precision manipulator that provides the tube ID to the eddy current system. Historically there have been some instances where the manipulator incorrectly reported the tube ID. This can have serious consequences including lack of inspection of a tube, or if a pluggable indication is detected, the tube is likely to be mis-plugged thereby risking a primary to secondary leak

  13. Vidicon storage tube electrical input/output

    Science.gov (United States)

    Lipoma, P.

    1972-01-01

    Electrical data storage tube is assembled from standard vidicon tube using conventional amplification and control circuits. Vidicon storage tube is simple, inexpensive and has an erase and preparation time of less than 5 microseconds.

  14. Vacuum distribution in the Vivitron accelerating tube

    International Nuclear Information System (INIS)

    Outgassing and conductance performances of HVEC type accelerating tube sections are calculated, measured and discussed. Based on the proposed Vivitron terminal stripping arrangement and tube pumping system, the vacuum pressure distribution along the accelerating tube has been determined

  15. Propagation and radiation characteristics of the circular electric, circular magnetic and hybrid waveguide modes

    International Nuclear Information System (INIS)

    The field distributions and propagation constants of the circular electric, circular magnetic and hybrid modes of oversized waveguides are expressed, taking the effects of walls into account. The near and far field patterns are derived in the case of real wall functions. It is shown that, for very oversized waveguides, the terms containing wall functions can be ignored in the calculations, and it results that the expressions of fields and propagation constants become independent of the types of waveguides. An application to corrugated waveguides for Electron Cyclotron Resonance Heating experiments shows the variations of the radiation characteristics versus geometric parameters of the corrugations and determines the ranges of interest for these parameters. (author)

  16. Multipole Analysis of Circular Cylindircal Magnetic Systems

    Energy Technology Data Exchange (ETDEWEB)

    J Selvaggi

    2006-01-09

    This thesis deals with an alternate method for computing the external magnetic field from a circular cylindrical magnetic source. The primary objective is to characterize the magnetic source in terms of its equivalent multipole distribution. This multipole distribution must be valid at points close to the cylindrical source and a spherical multipole expansion is ill-equipped to handle this problem; therefore a new method must be introduced. This method, based upon the free-space Green's function in cylindrical coordinates, is developed as an alternative to the more familiar spherical harmonic expansion. A family of special functions, called the toroidal functions or Q-functions, are found to exhibit the necessary properties for analyzing circular cylindrical geometries. In particular, the toroidal function of zeroth order, which comes from the integral formulation of the free-space Green's function in cylindrical coordinates, is employed to handle magnetic sources which exhibit circular cylindrical symmetry. The toroidal functions, also called Q-functions, are the weighting coefficients in a ''Fourier series-like'' expansion which represents the free-space Green's function. It is also called a toroidal expansion. This expansion can be directly employed in electrostatic, magnetostatic, and electrodynamic problems which exhibit cylindrical symmetry. Also, it is shown that they can be used as an alternative to the Elliptic integral formulation. In fact, anywhere that an Elliptic integral appears, one can replace it with its corresponding Q-function representation. A number of problems, using the toroidal expansion formulation, are analyzed and compared to existing known methods in order to validate the results. Also, the equivalent multipole distribution is found for most of the solved problems along with its corresponding physical interpretation. The main application is to characterize the external magnetic field due to a six

  17. MHD stability of an almost circular tokamak

    International Nuclear Information System (INIS)

    In a tokamak, the ratio β between the plasma pressure and that of the magnetic field is limited by the appearance of instabilities. The magnetic field in a tokamak reactor will always be limited by technological constraints. It is therefore crucial to know what factors have an effect on the β limit, since a zero resistivity plasma fluid model allows for theoretical reproduction of the β limits observed experimentally. Theoretical studies have shown that the distributions of pressure and current density may have a substantial effect on the β limit. The effect of the current density and pressure distributions on the β limit has been studied for tokamak with a circular core section. The best results are obtained when the current density is concentrated in the centre of the section and is nil at the periphery. But the second region of stability against ballooning modes cannot be obtained in a circular tokamak owing to the destabilisation of the universal modes. This study was then extended to the stability of plasmas the section of which is almost circular and has a point of reflection. Such configurations are vital for fusion since they allow systems in which the confinement time does not deteriorate with an increase in the additional heating power. The β limit was calculated for different positions of the reflection point. The results show that when it is displaced from the interior towards the exterior of the torus, the stability of the overall modes is progressively improved until it is vertical. But if the point of reflection is further displaced from this vertical position towards the exterior of the torus, localised modes close to the edge of the plasma are destabilised and bring about a drop in the β limit. (author) figs., tabs., 80 refs

  18. Porphyrin Protonation Studied by Magnetic Circular Dichroism

    Czech Academy of Sciences Publication Activity Database

    Štěpánek, Petr; Andrushchenko, Valery; Ruud, K.; Bouř, Petr

    2012-01-01

    Roč. 116, č. 1 (2012), s. 778-783. ISSN 1089-5639 R&D Projects: GA ČR GAP208/11/0105; GA ČR GA203/09/2037; GA ČR GAP208/10/0559; GA MŠk(CZ) LH11033 Institutional research plan: CEZ:AV0Z40550506 Keywords : magnetic circular dichroism (MCD) * TPPS * spectra simulations * porphyrin protonation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.771, year: 2012

  19. The radiating part of circular sources

    OpenAIRE

    Carley, Michael

    2010-01-01

    An analysis is developed linking the form of the sound field from a circular source to the radial structure of the source, without recourse to far-field or other approximations. It is found that the information radiated into the field is limited, with the limit fixed by the wavenumber of source multiplied by the source radius (Helmholtz number). The acoustic field is found in terms of the elementary fields generated by a set of line sources whose form is given by Chebyshev polynomials of the ...

  20. Wideband Circularly Polarized Dielectric Rod Antenna

    OpenAIRE

    Min Guo; Ji-Jun Yan; Shun-Shi Zhong; Zhu Sun

    2012-01-01

    A new dielectric rod antenna (DRA) is introduced to produce circular polarization (CP) over a wide frequency band without a complex feed network. Along with the simulated results, measured results of the antenna prototype are presented, showing a 3 dB axial ratio (AR) CP bandwidth of 17.7%. The radiation characteristics of the fabricated antenna are also demonstrated showing the measured gain of better than 6.2 dBi. Moreover, the measured impedance bandwidth (VSWR ≤2) reaches 20.1%, from 8.75...