WorldWideScience

Sample records for assessing tube wall

  1. Double wall steam generator tubing

    International Nuclear Information System (INIS)

    Padden, T.R.; Uber, C.F.

    1983-01-01

    Double-walled steam generator tubing for the steam generators of a liquid metal cooled fast breeder reactor prevents sliding between the surfaces due to a mechanical interlock. Forces resulting from differential thermal expansion between the outer tube and the inner tube are insufficient in magnitude to cause shearing of base metal. The interlock is formed by jointly drawing the tubing, with the inside wall of the outer tube being already formed with grooves. The drawing causes the outer wall of the inner tube to form corrugations locking with the grooves. (author)

  2. Assessment of thin-walled cladding tube mechanical properties by segmented expanding Mandrel test

    International Nuclear Information System (INIS)

    Nilsson, Karl-Fredrik

    2015-01-01

    This paper presents the principles of the segmented expanding mandrel test for thin-walled cladding tubes, which can be used as a basic material characterisation test to determine stress-strain curves and ductility or as a test to simulate mechanical pellet-cladding interaction. The paper discusses the strengths and weaknesses of the test method and it illustrates how the test can be used to simulate hydride reorientations in zirconium claddings and quantify how hydride reorientation affects ductility. (authors)

  3. Place Atrium to Water Seal (PAWS): Assessing Wall Suction Versus No Suction for Chest Tubes After Open Heart Surgery.

    Science.gov (United States)

    Kruse, Tamara; Wahl, Sharon; Guthrie, Patricia Finch; Sendelbach, Sue

    2017-08-01

    Traditionally chest tubes are set to -20 cm H 2 O wall suctioning until removal to facilitate drainage of blood, fluid, and air from the pleural or mediastinal space in patients after open heart surgery. However, no clear evidence supports using wall suction in these patients. Some studies in patients after pulmonary surgery indicate that using chest tubes with a water seal is safer, because this practice decreases duration of chest tube placement and eliminates air leaks. To show that changing chest tubes to a water seal after 12 hours of wall suction (intervention) is a safe alternative to using chest tubes with wall suction until removal of the tubes (usual care) in patients after open heart surgery. A before-and-after quality improvement design was used to evaluate the differences between the 2 chest tube management approaches in chest tube complications, output, and duration of placement. A total of 48 patients received the intervention; 52 received usual care. The 2 groups (intervention vs usual care) did not differ significantly in complications (0 vs 2 events; P = .23), chest tube output (H 1 = 0.001, P = .97), or duration of placement (median, 47 hours for both groups). Changing chest tubes from wall suction to water seal after 12 hours of wall suction is a safe alternative to using wall suctioning until removal of the tubes. ©2017 American Association of Critical-Care Nurses.

  4. Failure analysis of the boiler water-wall tube

    OpenAIRE

    S.W. Liu; W.Z. Wang; C.J. Liu

    2017-01-01

    Failure analysis of the boiler water-wall tube is presented in this work. In order to examine the causes of failure, various techniques including visual inspection, chemical analysis, optical microscopy, scanning electron microscopy and energy dispersive spectroscopy were carried out. Tube wall thickness measurements were performed on the ruptured tube. The fire-facing side of the tube was observed to have experienced significant wall thinning. The composition of the matrix material of the tu...

  5. Nondestructive testing of welds on thin-walled tubing

    Science.gov (United States)

    Hagemaier, D. J.; Posakony, G. J.

    1969-01-01

    Special ultrasonic search unit, or transducer assembly, reliably inspects the quality of melt-through welds of fusion welded tubing couplers for hydraulic lines. This instrumentation can also be used to detect faulty braze bonds in thin-walled, small diameter joints and wall thickness of thin-walled metal tubing.

  6. Failure analysis of the boiler water-wall tube

    Directory of Open Access Journals (Sweden)

    S.W. Liu

    2017-10-01

    Full Text Available Failure analysis of the boiler water-wall tube is presented in this work. In order to examine the causes of failure, various techniques including visual inspection, chemical analysis, optical microscopy, scanning electron microscopy and energy dispersive spectroscopy were carried out. Tube wall thickness measurements were performed on the ruptured tube. The fire-facing side of the tube was observed to have experienced significant wall thinning. The composition of the matrix material of the tube meets the requirements of the relevant standards. Microscopic examinations showed that the spheroidization of pearlite is not very obvious. The failure mechanism is identified as a result of the significant localized wall thinning of the boiler water-wall tube due to oxidation.

  7. Leakproof Swaged Joints in Thin-Wall Tubing

    Science.gov (United States)

    Stuckenberg, F. H.; Crockett, L. K.; Snyder, W. E.

    1986-01-01

    Tubular inserts reinforce joints, reducing incidence of leaks. In new swaging technique, tubular inserts placed inside ends of both tubes to be joined. Made from thicker-wall tubing with outside diameter that matches inside diameter of thin tubing swaged, inserts support tube ends at joint. They ensure more uniform contact between swage fitting and tubing. New swaging technique developed for Al/Ti/V-alloy hydraulic supply lines.

  8. Stability of spiral welded tubes in Quay Walls

    NARCIS (Netherlands)

    Gresnigt, A.M.; van Es, S.H.J.

    2013-01-01

    A European research project (RFCS) has started to provide economic and safe guidance for the design of spirally welded tubes in combined walls. The main motivation for this project called COMBITUBE is that the current Eurocode 3 regulations for tubes in quay walls lead to uneconomic designs, because

  9. Impact of plasma tube wall thickness on power coupling in ICP sources

    International Nuclear Information System (INIS)

    Nawaz, Anuscheh; Herdrich, Georg

    2009-01-01

    The inductively heated plasma source at the Institute of Space Systems was investigated with respect to the wall thickness of the plasma tube using an air plasma. For this, the wall thickness of the quartz tube was reduced in steps from 2.5 to 1.25 mm. The significance of reducing the wall thickness was analyzed with respect to both the maximum allowable tube cooling power and the coupling efficiency. While the former results from thermal stresses in the tube's wall, the latter results from a minimization of magnetic field losses near the coil turns of the inductively coupled plasma (ICP) source. Analysis of the thermal stress could be validated by experimental data, i.e. the measurement of the tube cooling power when the respective tube structure failed. The coupling efficiency could be assessed qualitatively by simplified models, and the experimental data recorded show that coupling was improved far more than predicted.

  10. Expander for Thin-Wall Tubing

    Science.gov (United States)

    Pessin, R.

    1983-01-01

    Tool locally expands small-diameter tubes. Tube expander locally expands and deforms tube: Compressive lateral stress induced in elastomeric sleeve by squeezing axially between two metal tool parts. Adaptable to situations in which tube must have small bulge for mechanical support or flow control.

  11. Cell Wall Composition, Biosynthesis and Remodeling during Pollen Tube Growth

    Directory of Open Access Journals (Sweden)

    Jean-Claude Mollet

    2013-03-01

    Full Text Available The pollen tube is a fast tip-growing cell carrying the two sperm cells to the ovule allowing the double fertilization process and seed setting. To succeed in this process, the spatial and temporal controls of pollen tube growth within the female organ are critical. It requires a massive cell wall deposition to promote fast pollen tube elongation and a tight control of the cell wall remodeling to modify the mechanical properties. In addition, during its journey, the pollen tube interacts with the pistil, which plays key roles in pollen tube nutrition, guidance and in the rejection of the self-incompatible pollen. This review focuses on our current knowledge in the biochemistry and localization of the main cell wall polymers including pectin, hemicellulose, cellulose and callose from several pollen tube species. Moreover, based on transcriptomic data and functional genomic studies, the possible enzymes involved in the cell wall remodeling during pollen tube growth and their impact on the cell wall mechanics are also described. Finally, mutant analyses have permitted to gain insight in the function of several genes involved in the pollen tube cell wall biosynthesis and their roles in pollen tube growth are further discussed.

  12. Control of Cell Wall Extensibility during Pollen Tube Growth

    OpenAIRE

    Hepler, Peter K.; Rounds, Caleb M.; Winship, Lawrence J.

    2013-01-01

    Tip-growing pollen tubes achieve rapid elongation while maintaining cell wall integrity by balancing local expansion, controlled by local changes in wall viscosity, against exocytosis, influenced by the activity of the actin cytoskeleton, cellular energetics, and calcium and proton physiology.

  13. Flame oscillations in tubes with nonslip at the walls

    Energy Technology Data Exchange (ETDEWEB)

    Akkerman, V' yacheslav; Bychkov, Vitaly; Petchenko, Arkady [Institute of Physics, Umeaa University, SE-901 87 Umeaa (Sweden); Eriksson, Lars-Erik [Department of Applied Mechanics, Chalmers University of Technology, 412 96 Goeteborg (Sweden)

    2006-06-15

    A laminar premixed flame front propagating in a two-dimensional tube is considered with nonslip at the walls and with both ends open. The problem of flame propagation is solved using direct numerical simulations of the complete set of hydrodynamic equations including thermal conduction, diffusion, viscosity, and chemical kinetics. As a result, it is shown that flame interaction with the walls leads to the oscillating regime of burning. The oscillations involve variations of the curved flame shape and the velocity of flame propagation. The oscillation parameters depend on the characteristic tube width, which controls the Reynolds number of the flow. In narrow tubes the oscillations are rather weak, while in wider tubes they become stronger with well-pronounced nonlinear effects. The period of oscillations increases for wider tubes, while the average flame length scaled by the tube diameter decreases only slightly with increasing tube width. The average flame length calculated in the present work is in agreement with that obtained in the experiments. Numerical results reduce the gap between the theory of turbulent flames and the experiments on turbulent combustion in tubes. (author)

  14. No rotating U.S. Testing of thin walled tubes

    International Nuclear Information System (INIS)

    Furlan, J.; Boulanger, G.; Mogavero, R.

    1981-07-01

    Thin walled tube ultrasonic testing is performed, with Lamb waves, using annular transducers and conical or helicoidal mirrors. The main advantage of this already known system is dispensing with rotation of tube and/or transducer. High speed control (30 cm/s and more) is then allowed. The present paper describes the parameters influencing the sensitivity has been improved by searching, theoretically and practically, the best suited Lamb wave modes, and by using transducers which are well characterized. Practical example of cladding tube U.S. testing is described

  15. Creep behaviour of thin walled composite tubes

    International Nuclear Information System (INIS)

    Thiebaud, F.; Muzic, B.; Perreux, D.; Varchon, D.; Oytana, C.; Lebras, J.

    1993-01-01

    Fiber reinforced composites are more and more employed in high performance structure for nuclear power plant, mainly as water piping tubes. The increase of the use of composites is due to the advantages that they give : high stiffness, large ultimate strength, corrosion resistance. This last advantage is sought for the pieces in contact with water, and it's one of the reason why the composite can be preferred to metal. However the mechanical behaviour of composite is actually poorly known. The high anisotropy is the main difficulty to obtain a realistic model of behaviour. This problem implies that the safety factor used in the design of structure is often too large. In this article a general overview of the mechanical behaviour of tube made in glass epoxy material is proposed. We discuss especially the creep behaviour under biaxial loadings. The form of the proposed model presently allows predicting a nonlinearity of the behaviour and provides a good correlation with the experimental data of several tests not described in this paper. It accounts for the change of the Poisson ratio during creep and cyclic tests. However the complete identification requires long time testings and consequently the model must be corrected to take into account the damage which occurs in these cases

  16. Multi-wall nanotube as tube dislocation

    International Nuclear Information System (INIS)

    Berredo-Peixoto, G. de; Shapiro, I.L.; Katanaev, M.O.; Konstantinova, E.

    2011-01-01

    Full text: The recently invented cylindrical geometric space defect is applied to the electron behaviour in the system which can be regarded as a simplified model of a double-wall nanotube. By solving the Schrodinger equation in the region of space with cylindrical geometric defect we explore the influence of such geometric defect on the energy gap and charge distribution. The effect is qualitatively similar to the one obtained earlier by means of traditional simulation methods. In general, the geometric approach can not compete with the known methods of theoretical study of the nanostructures, such as molecular dynamics. However it may be useful for better qualitative understanding of the electronic properties of the nanosystems. It is obvious that the method based on geometric defects can not compete with the standard approaches based on molecular dynamics. The reason is that the geometric defects method can not take into account full details of the structure of the compound and is, in some sense, too general. At the same time this method may become much more interesting if one develops it further and, in particular, learns how to deal with more sophisticated versions of geometric defects. In particular, it looks possible to take into account the chirality of the nanotube and, also, include the external magnetic field. We expect to consider these issues elsewhere. (author)

  17. Development of the double-wall-tube steam generator. Evaluation of inner tube leak detection system

    International Nuclear Information System (INIS)

    Teraoku, Takuji; Kisohara, Naoyuki

    1995-01-01

    A double-wall-tube steam generator (DWT-SG) is considered to have possibility of eliminating a secondary heat transport system to realize a reliable and simplified FBR plant. Thus, basic tests for inner/outer tube leak detection and prototypical leak tests by use of the 1MWt DWT-SG model have been performed to evaluate the feasibility of DWT-SG. Their results demonstrated that the inner leak detection system can definitely detect a steam leak from an inner tube flaw. Analyses of the inner tube leak and detection behavior obtained in the 1MWt DWT-SG test enabled to estimate the performance of the inner tube detection system of the commercial DWT-SG system. (author)

  18. Geometric Relations for CYLEX Test Tube-Wall Motion

    Science.gov (United States)

    Hill, Larry

    2015-06-01

    The CYLinder EXpansion (CYLEX) test is a (precision, instrumented, high-purity annealed copper) pipe bomb. Its essential measured quantities are detonation speed and tube-wall motion. Its main purpose is to calibrate detonation product equations of state (EOS) by measuring how product fluid pushes metal. In its full complexity, CYLEX is an integral test, for which EOS calibration requires the entire system to be computationally modeled and compared to salient data. Stripped to its essence, CYLEX is a non-integral test for which one may perform the inverse problem, to infer the EOS directly from data. CYLEX analysis can be simplified by the fact that the test constituents achieve a steady traveling wave structure; this allows derivation of several useful geometric relationships regarding tube wall motion. The first such treatment was by G.I. Taylor. Although his analysis was limited to small wall deflection angles, he asserted that the results remain valid for arbitrary ones. I confirm this attribute and present additional useful relationships. In the past decade, CYLEX wall-motion instrumentation has migrated almost entirely from streak camera to PDV, yet discrepancies remain between the two methods. I further present geometric relationships that shed light on this issue. Work supported by the U.S. DOE.

  19. Shock-tube study of fusion plasma-wall interactions

    International Nuclear Information System (INIS)

    Gross, R.A.; Tien, J.K.; Jensen, B.; Panayotou, N.F.; Feinberg, B.

    1977-01-01

    Theoretical and experimental studies have been made of phenomena which occur when a hot (T 1 approximately equal to 6 x 10 6 0 K), dense (n approximately equal to 10 16 cm -3 ), deuterium plasma containing a transverse magnetic field is brought into sudden contact with a cold metal wall. These studies are motivated by the need to understand plasma and metallurgical conditions at the first-wall of a fusion reactor. Experiments were carried out in the Columbia high energy electromagnetic shock tube. Computational simulation was used to investigate the detailed physics of the fusion plasma boundary layer which develops at the wall. The rate of energy transfer from the plasma to the wall was calculated and conditions under which surface melting occurs are estimated. Experimental measurements of plasma-wall heat transfer rates up to 3 x 10 5 watts/cm 2 were obtained and agreement with computed values are good. Fusion reactor first-wall materials have been exposed to 6.0 x 10 21 eV cm -2 (1,000 shots) of deuterium plasma bombardment. Scanning electron micrograph photographs show preferential erosion at grain boundaries, formation of deuterium surface blisters, and evidence of local surface melting. Some cracking is observed along grain boundaries, and a decrease in tensile ductiity is measured

  20. Viability of thin wall tube forming of ATF FeCrAl

    Energy Technology Data Exchange (ETDEWEB)

    Maloy, Stuart Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Aydogan, Eda [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Anderoglu, Osman [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lavender, Curt [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-16

    Fabrication of thin walled tubing of FeCrAl alloys is critical to its success as a candidate enhanced accident-tolerant fuel cladding material. Alloys that are being investigated are Generation I and Generation II FeCrAl alloys produced at ORNL and an ODS FeCrAl alloy, MA-956 produced by Special Metals. Gen I and Gen II FeCrAl alloys were provided by ORNL and MA-956 was provided by LANL (initially produced by Special Metals). Three tube development efforts were undertaken. ORNL led the FeCrAl Gen I and Gen II alloy development and tube processing studies through drawing tubes at Rhenium Corporation. LANL received alloys from ORNL and led tube processing studies through drawing tubes at Century Tubing. PNNL led the development of tube processing studies on MA-956 through pilger processing working with Sandvik Corporation. A summary of the recent progress on tube development is provided in the following report and a separate ORNL report: ORNL/TM-2015/478, “Development and Quality Assessments of Commercial Heat Production of ATF FeCrAl Tubes”.

  1. Pectin and the role of the physical properties of the cell wall in pollen tube growth of Solanum chacoense.

    Science.gov (United States)

    Parre, Elodie; Geitmann, Anja

    2005-02-01

    The cell wall is one of the structural key players regulating pollen tube growth, since plant cell expansion depends on an interplay between intracellular driving forces and the controlled yielding of the cell wall. Pectin is the main cell wall component at the growing pollen tube apex. We therefore assessed its role in pollen tube growth and cytomechanics using the enzymes pectinase and pectin methyl esterase (PME). Pectinase activity was able to stimulate pollen germination and tube growth at moderate concentrations whereas higher concentrations caused apical swelling or bursting in Solanum chacoense Bitt. pollen tubes. This is consistent with a modification of the physical properties of the cell wall affecting its extensibility and thus the growth rate, as well as its capacity to withstand turgor. To prove that the enzyme-induced effects were due to the altered cell wall mechanics, we subjected pollen tubes to micro-indentation experiments. We observed that cellular stiffness was reduced and visco-elasticity increased in the presence of pectinase. These are the first mechanical data that confirm the influence of the amount of pectins in the pollen tube cell wall on the physical parameters characterizing overall cellular architecture. Cytomechanical data were also obtained to analyze the role of the degree of pectin methyl-esterification, which is known to exhibit a gradient along the pollen tube axis. This feature has frequently been suggested to result in a gradient of the physical properties characterizing the cell wall and our data provide, for the first time, mechanical support for this concept. The gradient in cell wall composition from apical esterified to distal de-esterified pectins seems to be correlated with an increase in the degree of cell wall rigidity and a decrease of visco-elasticity. Our mechanical approach provides new insights concerning the mechanics of pollen tube growth and the architecture of living plant cells.

  2. Investigation of the Geometry of Metal Tube Walls after Necking in Uniaxial Tension

    Directory of Open Access Journals (Sweden)

    Chong Li

    2017-03-01

    Full Text Available Abstract: In order to characterize the deformation and true stress–strain relation of metal tubes, the geometry of tube walls after necking in uniaxial tension need to be determined. The paper investigated the necking process of metal tube. A large number of tensile tests and finite element analysis of 1Cr18Ni9Ti tubes with different sizes were conducted. It was found that the geometry of outer tube wall in the necking region can be described using a logistic regression model. The final geometry of the tube is determined by original tube diameter and wall thickness. The offset of tube walls are affected by two competing factors: volume constancy and necking. The offset distances of outer and inner walls are mainly affected by original wall thickness. The length of the necking zone is more influenced by original tube diameter. Tube elongation at fracture increases slightly as tube diameter gets larger, while the wall thickness has almost no impact on the elongation.

  3. Ultrasonic inspection of steam generator tubing for cracks, wall thinning and cross-sectional deformation

    International Nuclear Information System (INIS)

    Meyer, P.A.; Carodiskey, T.J.

    1988-01-01

    Periodic inspection of steam generator tubing is an important consideration in the efficient operation of a power generating facility. Since the operating life of these generators is finite, failures will occur. Due to the chemistry of the environment, thermal cycling, and other factors, flaws may develop that can cause rapid deterioration of the tubing while the overall performance of the unit may appear normal. In earlier presentation, the authors presented an ultrasonic bore-side array transducer which can be used with a conventional flaw detector instrument for the location of circumferential crack type defects on the outside tube surface. since that time, much additional experience has been gained on the performance of these probes. Probe performance has been characterized using fatigue crack samples and these results are reviewed. Probes have also been developed having 16 elements for use in larger diameter (25 mm) tubes. The bore-side array concept has been expanded to normal incidence tube well inspection allowing simultaneous wall thickness and eccentricity measurement which is very useful in the assessment of tube wastage and deformation. Preliminary data obtained in this area is presented

  4. 75 FR 82070 - Light-Walled Rectangular Pipe and Tube From China, Korea, and Mexico

    Science.gov (United States)

    2010-12-29

    ...-Walled Rectangular Pipe and Tube From China, Korea, and Mexico AGENCY: United States International Trade... from China, Korea, and Mexico that were found to be sold at less than fair value. Nacional de Acero S... panel proceeding in Light-Walled Rectangular Pipe and Tube from Mexico, USA-MEX-1904-04, to file...

  5. ANL/CANTIA code for steam generator tube integrity assessment

    International Nuclear Information System (INIS)

    Revankar, S.T.; Wolf, B.; Majumdar, S.; Riznic, J.R.

    2009-01-01

    Steam generator (SG) tubes have an important safety role in CANDU type reactors and Pressurized Water Reactors (PWR) because they constitute one of the primary barriers between the radioactive and non-radioactive sides of the nuclear plant. The SG tubes are susceptible to corrosion and damage. A failure of a single steam generator tube, or even a few tubes, would not be a serious safety-related event in a CANDU reactor. The leakage from a ruptured tube is within makeup capacity of the primary heat transport system, so that as long as the operator takes the correct actions, the off-site consequences will be negligible. A sufficient safety margin against tube rupture used to be the basis for a variety of maintenance strategies developed to maintain a suitable level of plant safety and reliability. Several through-wall flaws may remain in operation and potentially contribute to the total primary-to-secondary leak rate. Assessment of the conditional probabilities of tube failures, leak rates, and ultimately risk of exceeding licensing dose limits has been used for steam generator tube fitness-for-service assessment. The advantage of this type of analysis is that it avoids the excessive conservatism typically present in deterministic methodologies. However, it requires considerable effort and expense to develop all of the failure, leakage, probability of detection, and flaw growth distributions and models necessary to obtain meaningful results from a probabilistic model. The Canadian Nuclear Safety Commission (CNSC) recently developed the CANTIA methodology for probabilistic assessment of inspection strategies for steam generator tubes as a direct effect on the probability of tube failure and primary-to-secondary leak rate Recently Argonne National Laboratory has developed tube integrity and leak rate models under Integrated Steam Generator Tube Integrity Program (ISGTIP-2). These models have been incorporated in the ANL/CANTIA code. This paper presents the ANL

  6. Multiaxial loading of large-diameter, thin-walled tube rock specimens

    International Nuclear Information System (INIS)

    Hecker, S.S.; Petrovic, J.J.

    1981-01-01

    A large-scale mechanical testing facility permits previously impossible thin-walled tube multiaxial loading experiments on rock materials. Constraints are removed regarding tube wall thickness in relation to rock microstructural features and tube diameter as well as test machine load capacity. Thin-walled tube studies clarify the influence of intermediate principal stress sigma 2 on rock fracture and help define a realistic rock fracture criterion for all multiaxial stressing situations. By comparing results of thin-walled and thick-walled tube fracture investigations, effects of stress gradients can be established. Finally, influence of stress path on rock fracture, an area largely ignored in current rock failure criteria, can be examined in detail using controlled loading changes as well as specimen prestrains

  7. Wall thickness measurements of tubes by Internal Rotary Inspection System (IRIS)- a comparative study with metallography

    International Nuclear Information System (INIS)

    Subramanian, C.V.; Joseph, A.; Ramesh, A.S.; Jayakumar, T.; Kalyanasundaram, P.; Baldev Raj

    1996-01-01

    Internal Rotary Inspection System (IRIS) is a relatively new ultrasonic system of heat exchanger/ steam condenser tubes and pipelines for measurement of wall thinning and pitting due to corrosion. The wall thickness measurements made during a scan around the circumference of the tube are displayed as a stationary rectilinear display of circumferential cross section (Bscan) of the tube. The paper describes the results obtained on tubes of various materials used in process industries having corrosion on inner and outer surfaces of the tube. (author)

  8. Analysis of prestressed double-wall tubing for LMFBR steam generators

    International Nuclear Information System (INIS)

    Uber, C.F.; Langford, P.J.

    1981-01-01

    A radial interface pressure is provided between the inner and outer tubes of each double-wall tube in a steam generator design now being developed for commercial breeder reactor plants. This paper describes a finite element analysis of the manufacturing technique used to prestress the double-wall tube. The analytical predictions are compared with experimental measurements of the residual interface pressure. Resulting residual stress states are used as the starting point for operating condition analyses. 9 refs

  9. Current Status on the Development of a Double Wall Tube Steam Generator

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Ho Yun; Choi, Byoung Hae; Kim, Jong Man; Kim, Byung Ho

    2007-12-15

    A fast reactor, which uses sodium as a coolant, has a lot of merits as a next generation nuclear reactor. However, the possibility of a sodium-water reaction occurrence hinders the commercialization of this reactor. As one way to improve the reliability of a steam generator, a double-wall tube steam generator is being developed in GEN-4 program. In this report, the current state of the technical developments for a double-wall tube steam generator are reviewed and a future plan for the development of a double-wall tube steam generator is established. The current focuses of this research are an improvement of the heat transfer capability for a double-wall tube and the development of a proper leak detection method for the failure of a double-wall tube during a reactor operation. The ideal goal is an on-line leak detection of a double wall tube to prevent the sodium-water reaction. However, such a method is not developed as yet. An alternative method is being used to improve the reliability of a steam generator by performing a non-destructive test of a double wall tube during the refueling period of a reactor. In this method a straight double wall tube is employed to perform this test easily, but has a difficulty regarding an absorption of a thermal expansion of the used materials. If an on-line leak detection method is developed, the demerits of a straight double-wall tube are avoided by using a helical type double-wall tube, and the probability of a sodium-water reaction can be reduced to a level less than the design-based accident.

  10. Development of a helical-coil double wall tube steam generator for 4S reactor

    International Nuclear Information System (INIS)

    Kitajima, Yuko; Maruyama, Shigeki; Jimbo, Noboru; Hino, Takehisa; Sato, Katsuhiko

    2011-01-01

    The 4S, Super-Safe Small and Simple, is a small-sized sodium-cooled fast reactor. A fast reactor usually uses sodium as a coolant to transfer heat from core to turbine/generator system. The heat of the intermediate heat transport system and that of the water stream systems are exchanged by the steam generator (SG) tubes. If the tube failure occurs, a sodium/water reaction could be occurred. To prevent the reaction and enhance safety, a helical-coil-type double wall tube with wire mesh interlayer and continuous monitoring systems of tube failure are applied to the SG of the 4S. The development and general features of this type double wall tube were described in Ref. 1) and Ref. 2). Those paper summarized following results; The tubes studied in these references were straight type. To establish this SG, development of manufacturing method of helical-coil-type double wall tube and validation of the tube failure monitoring system are needed. In this study, three demonstration tests have been performed; welding test of the double wall tube to manufacture the tubes with 70-80m length, assembling test of the helical-coil tube, and confirmation test of the tube processing system using the fabricated helical-coil tubes. As a result, following technologies have been successfully established. (1) Development of the welding techniques for manufacturing of the helical-coil-type double wall tube with wire mesh interlayer. (2) The confirmation test for manufacturing the helical coil tube of the SG. (author)

  11. Creep collapse of thick-walled heat transfer tube subjected to external pressure at high temperature

    International Nuclear Information System (INIS)

    Ioka, Ikuo; Kaji, Yoshiyuki; Terunuma, Isao; Nekoya, Shin-ichi; Miyamoto, Yoshiaki

    1994-09-01

    A series of creep collapse tests of thick-walled heat transfer tube were examined experimentally and analytically to confirm an analytical method for creep deformation behavior of a heat transfer tube of an intermediate heat exchanger (IHX) at a depressurization accident of secondary cooling system of HTTR (High Temperature Engineering Test Reactor). The tests were carried out using thick-walled heat transfer tubes made of Hastelloy XR at 950degC in helium gas environment. The predictions of creep collapse time obtained by a general purpose FEM-code ABAQUS were in good agreement with the experimental results. A lot of cracks were observed on the outer surface of the test tubes after the creep collapse. However, the cracks did not pass through the tube wall and, therefore, the leak tightness was maintained regardless of a collapse deformation for all tubes tested. (author)

  12. Reliability of double-wall-tube steam generator for FBR considering water leak accident frequency

    International Nuclear Information System (INIS)

    Ueda, Nobuyuki; Kinoshita, Izumi; Nishi, Yoshihisa

    2000-01-01

    For early realization, a fast breeder reactor (FBR) is required to reduce construction cost. A reactor concept in which the intermediate heat transport system is eliminated by introducing a double-wall-tube steam generator is one convincing approach. The reliability of the double-wall-tube SG in a water leak accident (sodium-water reaction accident) due to tube failure is strongly related to the mitigating system design. The safety design of the double-wall-tube SG approach is investigated to limit the accident occurrence below 10 -7 (1/ry. A tube-to-tube weld is excluded from the reference design, because the welding process is too difficult and complicated to effectively prevent adhesion of the double-wall-tube. The reliability of the tube-to-tube plate was evaluated at 10 -10 (l/hr) for an inner tube and 10 -9 (l/hr) for an outer with reference to the failure experience of previous SGs. The failure must be detected within 30 to 60 minutes. (author)

  13. 78 FR 42546 - Light-Walled Rectangular Pipe and Tube From China, Korea, Mexico, and Turkey: Notice of...

    Science.gov (United States)

    2013-07-16

    ...-Walled Rectangular Pipe and Tube From China, Korea, Mexico, and Turkey: Notice of Commission... countervailing duty order on light-walled rectangular pipe and tube from China and the antidumping duty orders on light-walled rectangular pipe and tube from China, Korea, Mexico, and Turkey would be likely to lead to...

  14. 78 FR 74161 - Light-Walled Rectangular Pipe and Tube From China, Korea, Mexico, and Turkey; Scheduling of Full...

    Science.gov (United States)

    2013-12-10

    ...-Walled Rectangular Pipe and Tube From China, Korea, Mexico, and Turkey; Scheduling of Full Five-Year... the Antidumping Duty Orders on Light-Walled Rectangular Pipe and Tube From China, Korea, Mexico, and... on light- walled rectangular pipe and tube from China, Korea, Mexico, and Turkey would be likely to...

  15. Location and optimization analysis of capillary tube network embedded in active tuning building wall

    International Nuclear Information System (INIS)

    Niu, Fuxin; Yu, Yuebin

    2016-01-01

    In this study, a building wall with a thermal tuning function is further investigated. This design turns the building wall from a passive thermal system to an active system. A capillary tube network is installed inside the wall to manipulate the thermodynamics and realize more flexibility and potentials of the wall. This novel building wall structure performs efficiently in terms of building load reduction and supplementary heating and cooling, and the structure is convenient for applying low grade or natural energy with a wider temperature range. The capillary tube network's location inside the wall greatly impacts the thermal and energy performance of the building wall. The effects of three locations including external, middle and internal side are analyzed. The results indicate that the internal wall surface temperature can be neutralized from the ambient environment when the embedded tubes are fed with thermal water. The wall can work with a wide range of water temperature and the optimal location of the tube network is relatively constant in different modes. Power benefit with the wall changes from 2 W to 39 W when the outdoor air temperature changes, higher in summer than in winter. - Highlights: • A building wall with a tuning function is proposed using a capillary pipe network. • Low-grade thermal water can be used to actively manipulate the thermal mass. • Location of the capillary network is investigated to maximize the performance. • The innovation can potentially lower down the grade of energy use in buildings.

  16. Studying energy absorption in tapered thick walled tubes

    Directory of Open Access Journals (Sweden)

    P. Hosseini Tehrani

    Full Text Available In many engineering structures different energy absorption systems may be used to improve crashworthiness capability of the system and to control damages that may occur in a system during an accident. Therefore, extensive research has been done on the energy-absorbing cells. In this paper, energy absorption in tapered thick walled tubes has been investigated. As a practical case, studies have been focused on the crush element of Siemens ER24PC locomotive. To investigate performance of this part at collision time, it has been modeled in Abaqus software and its collision characteristics have been evaluated. Considering that the crash element is folded at time of collision, an analytical approach has been presented for calculation of instantaneous folding force under axial load. Basis of this method is definition and analysis of main folding mechanism and calculation of average folding force. This method has been used for validation of the results of numerical solution. Since sheet thickness of the crash element is high and may be ruptured at time of collision, some damage models have been used for numerical simulations. One of the three damage models used in this paper is available in the software and coding has been done for two other damage models and desirable damage model has been specified by comparing results of numerical solution with results of laboratory test. In addition, authenticity of the desirable damage model has been studied through ECE R 66 standard. To improve crashworthiness characteristic some attempts, such as use of metal foam and creation of trigger in suitable situations to reduce maximum force resulting from collision, have been performed. Finally though different simulation optimal crush element has been introduced and its performance and efficiency have been evaluated.

  17. Thin-walled beam tubes for the SIS. Construction and manufacturing

    International Nuclear Information System (INIS)

    Malwitz, E.

    1985-06-01

    The vacuum system of the SIS consists essentially of torus-shaped vacuum chamber with an annulus-circumference of 216 m which is composed by several beam-tube and chamber elements. In order to reach the desired final pressure of -11 mbar (5 . 10 -9 Pa) a heating of the whole vacuum system to 300 0 C is required. The beam tubes within magnets have regularly an elliptic tube cross section. Within bending magnets the beam tubes are curved in a plane through the large ellipse axis with a bending radius of 10 m. During the development work for the beam tubes within magnets to construction variants were studied until construction maturity. Generally thin-walled beam tubes with elliptic tube cross section are fabricated similarly to spring bellows as corrugated tubes. In this report however beam tubes with elliptic tube cross section are discussed the tube walls of which are smooth and stabilized against the atmospheric pressure by hard-soldered ribs. The report reproduces mainly the most important know how respectively serves as instruction for new constructions. Such beam tubes are planned for the dipole magnets and the quadrupole group consisting of two long quadrupoles, a short quadrupole, and a sextupole. (orig./HSI) [de

  18. Radiometric measurements of wall temperatures in the 800 K to 1150 K range for a quartz radiant heating tube

    International Nuclear Information System (INIS)

    Blevins, L.G.; Sivathanu, Y.R.; Gore, J.P.; Shahien, M.A.

    1995-01-01

    Many industrial applications require heat transfer to a load in an inert environment, which can be achieved by using gas-fired radiant tubes. A radiant tube consists of a flame confined in a cylindrical metal or ceramic chamber. The flame heats the tube wall, which in turn radiates to the load. One important characteristic of radiant heating tubes is wall temperature uniformity. Numerical models of radiant tubes have been used to predict wall temperatures, but there is a lack of experimental data for validation. Recently, Namazian et al., Singh and Gorski, and Peters et al. have measured wall temperature profiles of radiant tubes using thermocouples. 13 refs., 3 figs

  19. Standard practice for estimating the approximate residual circumferential stress in straight thin-walled tubing

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 A qualitative estimate of the residual circumferential stress in thin-walled tubing may be calculated from the change in outside diameter that occurs upon splitting a length of the tubing. This practice assumes a linear stress distribution through the tube wall thickness and will not provide an estimate of local stress distributions such as surface stresses. (Very high local residual stress gradients are common at the surface of metal tubing due to cold drawing, peening, grinding, etc.) The Hatfield and Thirkell formula, as later modified by Sachs and Espey, provides a simple method for calculating the approximate circumferential stress from the change in diameter of straight, thin-walled, metal tubing. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  20. On the characteristics and application of thin wall welded titanium tubes for heat transfer

    International Nuclear Information System (INIS)

    Nishimura, Takashi; Miyamoto, Yoshiyuki

    1985-01-01

    Because of the excellent corrosion resistance, thin wall welded titanium tubes have become to be used in large number as the heat transfer tubes of condensers and seawater desalting plants using seawater in place of conventional copper alloy tubes. Especially in nuclear power plants, the all titanium condensers using thin wall welded titanium tubes and titanium tube plates were adopted in the almost all plants under construction or expected to be constructed. In this report, the various characteristics of thin wall welded titanium tubes required for using them as heat transfer tubes, such as corrosion resistance, heat transfer characteristics, fatigue strength and expanding characteristics, are outlined, and the state of use is described. At first, relatively thick seamless titanium tubes were used for chemical industry, but thereafter, due to the advance of the mass production techniques, the welded titanium tubes of less than 0.7 mm thickness and high quality have become to be supplied at low cost. In 1969, titanium tubes were used for the first time in Japan for the air cooler in the condenser of Akita Power Station, Tohoku Electric Power Co., Inc. The features of titanium are small specific gravity, small linear expansion coefficient and small Young's modulus. (Kako, I.)

  1. Light hydrogen isotopes in the single - walled carbon nano tube

    International Nuclear Information System (INIS)

    Khugaev, A.V.; Sultanov, R.A.; Guster, D.

    2007-01-01

    Full text: Progress of our understanding of the molecular hydrogen behavior in the nano tube interior open an intriguing possibility for the applications of these knowledge's to the solution of the hydrogen storage problem and light isotopes gas selectivity. That can strongly change the situation at the energy production in the world and completely change our civil life. These investigations underline the influence of the quantum effects on the properties of molecular hydrogen in the nano tube interior and it leads to the pure quantum-mechanical reformulation of the problem for the hydrogen behavior inside carbon nano tube as a problem of molecular quantum system behavior in the external field induced by the regular nano tube surface. In the present paper the molecular hydrogen behavior in the carbon nano tube was considered in the simple quantum mechanical manner. The main attention was paid to the investigation of the quantum sieving selectivity in the dependence of nano tube composition, radius and symmetry properties. For the interaction potential between hydrogen and nano tube surface was taken some phenomenological LJ(12,6) - (Lennard - Jones) potential and the external field induced by the nano tube in its interior is considered as a simple sum over the all nano tube carbon atoms. Influence of the structure of rotation (vibration) spectrum of the energy levels of diatomic molecules, such as H 2 , HD and D 2 on the final results and finite size of the nano tube along the axis of symmetry, its boundary effects is discussed in details. Thermal oscillations of nano tube surface were considered separately in the dependence of the temperature gradient along of the axis of symmetry

  2. Collapse of thin wall tubes with small initial ovality

    International Nuclear Information System (INIS)

    Moreno, A.

    1977-01-01

    A simple model of creep collapse of tubes based on the bending theory of curved beams is developed. The model is compared with more complex models. The main result of this study is the definition of a new model of creep collapse of tubes with a minimum of limited hypothesis. (author) [es

  3. Collapse of thin wall tubes small initial ovality

    International Nuclear Information System (INIS)

    Moreno, A.

    1977-01-01

    In this work a simple model of creep collapse of tubes based on the bending theory of curved beams, is developed. The model is compared with more complex models. The main result of this work is the definition of a new model of creep collapse of tubes with a minimum of limitative hypothesis. (Author) 6 refs

  4. Thermal fatigue crack growth on a thick wall tube containing a semi elliptical circumferential crack

    International Nuclear Information System (INIS)

    Deschanels, H.; Wakai, T.; Lacire, M.H.; Michel, B.

    2001-01-01

    In order to check the ability of the simplified assessment procedure (A16 guide) to predict fatigue crack growth, a benchmark problem was conducted. This work is carried out under the project ''agreement on the Exchange of Information and Collaboration in the field of Research and Development of Fast Breeder Reactor (FBR) between Europe (EU) and Japan''. Experimental work is conducted by PNC using Air cooled Thermal transient Test Facility (ATTF). Specimen is a thick wall tube containing a semi elliptical (3-D) circumferential crack and subjected to cyclic thermal transients. The constitutive material is the 304 austenitic stainless steel type SUS304. Due to thermal shock (650 C-300 C) the stress distribution through the wall is non-linear and well approximated using a 3 rd order polynomial. When comparing computations and tests data we observe a good agreement for the crack propagation in length. In crack depth, accurate results are obtained in the first part of the test, but on the later stage of the experiment the computations slightly underestimate the propagation (deep crack). In addition, we notice the importance of good evaluation of fracture mechanics parameters for non-linear stress distribution through the wall. At present A16 guide handbook gives stress intensity factor solutions for non-linear stress distribution through the wall. (author)

  5. Thin-walled large-diameter zirconium alloy tubes in CANDU reactors

    International Nuclear Information System (INIS)

    Price, E.G.; Richinson, P.J.

    1978-08-01

    The requirements of the thin-walled large-diameter Zircaloy-2 tubing used in CANDU reactors are reviewed. Strength, residual stress patterns, texture and prior deformation contribute to the stability of these tubes. The extent to which the present manufacturing route meets these requirements is discussed. (author)

  6. 77 FR 3497 - Light-Walled Rectangular Pipe and Tube From Taiwan

    Science.gov (United States)

    2012-01-24

    ... Rectangular Pipe and Tube From Taiwan Determination On the basis of the record \\1\\ developed in the subject... order on light-walled rectangular pipe and tube from Taiwan would be likely to lead to continuation or recurrence of material injury to an industry in the United States within a reasonably foreseeable time. \\1...

  7. How to operate safely steam generators with multiple tube through-wall defects

    International Nuclear Information System (INIS)

    Hernalsteen, P.

    1993-01-01

    For a Nuclear Power Plant (NPP) of the Pressurized Water Reactor (PWR) type, the Steam Generator (SG) tube bundle represents the major but also the thinnest part of the primary pressure boundary. To the extent that no tube material has yet been identified to be immune to corrosion, defects may initiate in service and easily propagate through wall. While not a desirable feature, a Through Wall Deep (TWD) defect does not necessarily pose a threat to either the structural integrity or leaktightness and this paper shows how SG can (and indeed, do) operate safely and reliably while having many tubes affected by deep and even TWD defects

  8. Integrity Assessment of GOH Heater Tube

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Bong Sang; Hong, J. H.; Oh, Y. J.; Yoon, J. H.; Oh, J. M. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-08-01

    An assessment of structural integrity of ASTM A312-TP347 GOH heater tube was performed. The surface notches which had been produced during tube manufacturing process were analyzed microscopically. Chemical analysis, hardness tests, tensile tests, and J-Integral fracture resistance tests were carried out to compare the mechanical properties with those of the material specification and also with the other material of the same type. The test results showed the mechanical properties of the GOH tube material are within the specification range. An elastic-plastic fracture mechanics analysis based on the DPFAD method reveals the tube an appropriate safety margin for the normal operation. 13 refs., 5 tabs., 24 figs. (author)

  9. Characterization of Thin Walled Mo Tubing produced by FBCVD

    Energy Technology Data Exchange (ETDEWEB)

    Beaux, Miles Frank [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Usov, Igor Olegovich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-01-21

    The goal of this report is to delineate the results of material characterization performed on Mo tubing produced via the fluidized bed chemical vapor deposition (FBCVD) method. Scanning electron microscopy (SEM) imaging reveals that small randomly oriented grains are achieved in the Mo deposition, but do not persist throughout the entire thickness of the material. Energy dispersive spectroscopy (EDS) reveals the Mo tubes contain residual chlorine and oxygen. EDS measurements on the tube surfaces separated from glass and quartz substrates reveal substrate material adhered to this surface. X-ray diffraction (XRD) revealed the presence of carbon contaminant in the form of Mo2C and oxygen in the form of MoO2. Combustion infrared detection (CID) and inert gas fusion (IGF) performed at Luvak Inc. was used to quantify weight percentages of oxygen and carbon in the tubes produced. Hardness value of the FBCVD Mo was found to be comparable to low carbon arc cast molybdenum.

  10. Current-driven vortex domain wall motion in wire-tube nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Espejo, A. P. [Departamento de Física, Universidad de Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago (Chile); Institute of Nanostructure and Solid State Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg (Germany); Vidal-Silva, N. [Departamento de Física, Universidad de Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago (Chile); López-López, J. A. [Departamento de Física, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile); Goerlitz, D.; Nielsch, K. [Institute of Nanostructure and Solid State Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg (Germany); Escrig, J. [Departamento de Física, Universidad de Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago (Chile); Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Av. Ecuador 3493, 9170124 Santiago (Chile)

    2015-03-30

    We have investigated the current-driven domain wall motion in nanostructures comprised of a pair of nanotube and nanowire segments. Under certain values of external magnetic fields, it is possible to pin a vortex domain wall in the transition zone between the wire and tube segments. We explored the behavior of this domain wall under the action of an electron flow applied in the opposite direction to the magnetic field. Thus, for a fixed magnetic field, it is possible to release a domain wall pinned simply by increasing the intensity of the current density, or conversely, for a fixed current density, it is possible to release the domain wall simply decreasing the magnetic external field. When the domain wall remains pinned due to the competition between the current density and the magnetic external field, it exhibits a oscillation frequency close to 8 GHz. The amplitude of the oscillations increases with the current density and decreases over time. On the other hand, when the domain wall is released and propagated through the tube segment, this shows the standard separation between a steady and a precessional regime. The ability to pin and release a domain wall by varying the geometric parameters, the current density, or the magnetic field transforms these wire-tube nanostructures in an interesting alternative as an on/off switch nano-transistor.

  11. Experimental facility design for a gap heat transfer in a double wall tube

    International Nuclear Information System (INIS)

    Nam, Ho Yun; Hong, Jong Gan; Kim, Jong Man; Kim, Jong Bum; Jeong, Ji Young

    2012-01-01

    A reliable steam generator design is one of the most critical issues in developing a sodium cooled fast reactor (SFR), and various efforts to avoid potential sodium water reaction (SWR) have been made. For this reason, SFR steam generators have been developed to improve its reliability using a double wall tube (DWT), which has two barriers between the sodium and water. Most steam generators for SFRs are the shell and tube type. Steam at high pressure and low temperature flows inside the inner tubes, which are heated by the shell side sodium at low pressure and high temperature. Since the inner and outer tubes of conventional DWTs are made of identical materials, the degree of thermal expansion is somewhat different between the two concentric tubes owing to their temperature difference. Therefore, a greater temperature difference results in less contact pressures between the inner and outer tubes. This feature results in a deterioration of the heat transfer capability of DWTs. Current developments are focused on an improvement of heat transfer capability by investigating the gap conductance between the two concentric tubes. To improve the heat transfer capability of DWTs, it is preferable to use different tube materials (Fig. 1). It is recommended to choose the inner tube material whose thermal expansion coefficient is greater than that of the outer tube by 10 to 15%

  12. Development of laser cladding system to repair wall thinning of 1-inch heat exchanger tube

    International Nuclear Information System (INIS)

    Terada, Takaya

    2013-01-01

    We developed a laser cladding system to repair the inner wall wastage of heat exchanger tubes. Our system, which is designed to repair thinning tube walls within 100 mm from the edge of a heat exchanger tube, consists of a fiber laser, a composite-type optical fiberscope, a coupling device, a laser processing head, and a wire-feeding device. All of these components were reconfigured from the technologies of FBR maintenance. The laser processing head, which has a 15-mm outer diameter, was designed to be inserted into a 1-inch heat exchanger tube. We mounted a heatproof broadband mirror for laser cladding and fiberscope observation with visible light inside the laser processing head. The wire-feeding device continuously supplied 0.4-mm wire to the laser irradiation spot with variable feeding speeds from 0.5 to 20 mm/s. We are planning to apply our proposed system to the maintenance of aging industrial plants. (author)

  13. Evaluation of the inner wall axial cracks of steam generator tubes by eddy current test

    International Nuclear Information System (INIS)

    Hur, Do Haeng; Choi, Myung Sik; Lee, Doek Hyun; Han, Jung Ho

    2001-01-01

    For the enhancement of ECT reliability on the primary water stress corrosion cracks of nuclear steam generator tubes, it is important to comprehend the signal characteristics on crack morphology and to select an appropriate probe type. In this paper, the sizing accuracy and the detectability for the inner wall axial cracks of tubes were quantitatively evaluated using the electric discharge machined notches and the corrosion cracks which were developed on the operating steam generator tubes. The difference of eddy current signal characteristics between pancake and axial coil were also investigated. The results obtained from this study provide a useful information for more precise evaluation on the inner wall axial cracks of steam generator tubes.

  14. Evaluation of Eddy Current Signals from the Inner Wall Axial Cracks of Steam Generator Tubes

    International Nuclear Information System (INIS)

    Choi, Myung Sik; Hur, Do Haeng; Lee, Doek Hyun; Han, Jung Ho; Park, Jung Am

    2001-01-01

    For the enhancement of ECT reliability on the primary water stress corrosion cracks of nuclear steam generator tubes, of which the occurrence is on the increase, it is important to comprehend the signal characteristics on crack morphology and to select an appropriate probe type. In this paper, the sizing accuracy and the detectability for the inner wall axial cracks of tubes were quantitatively evaluated using the following specimens: the electric discharge machined notches and the corrosion cracks which were developed on the operating steam generator tubes. The difference of eddy current signal characteristics between pancake and axial coil were also Investigated. The results obtained from this study provide a useful information for more precise evaluation on the inner wall axial tracks oi steam generator tubes

  15. Hydrogen storage in single-wall carbon nano-tubes by means of laser excitation

    International Nuclear Information System (INIS)

    Oksengorn, B.

    2010-01-01

    A new mode for hydrogen adsorption and storage in single-wall carbon nano-tubes is used, on the basis of laser excitation. Remember that this method has been useful to obtain, in the case of the fullerene C 60 , many complex C 60 -atoms or C 60 -molecules, where atoms or molecular particles are trapped inside the C 60 -molecules. We think this method might be important to store many hydrogen molecules inside carbon nano-tubes. (author)

  16. Hydrogen embrittlement corrosion failure of water wall tubes in large power station boilers

    International Nuclear Information System (INIS)

    Mathur, P.K.

    1981-01-01

    In the present paper, causes and mechanism of hydrogen embrittlement failure of water wall tubes in high pressure boilers have been discussed. A low pH boiler water environment, produced as a result of condenser leakage or some other type of system contamination and presence of internal metal oxide deposits, which permit boiler water solids to concentrate during the process of steam generation, have been ascribed to accelerate the formation of local corrosion cells conducive for acid attack resulting in hydrogen damage failure of water wall tubes. (author)

  17. The effect of atomic hydrogen adsorption on single-walled carbon nano tubes properties

    International Nuclear Information System (INIS)

    Jalili, S.; Majidi, R.

    2007-01-01

    We investigated the adsorption of hydrogen atoms on metallic single-walled carbon nano tubes using ab initio molecular dynamics method. It was found that the geometric structures and the electronic properties of hydrogenated SWNTs can be strongly changed by varying hydrogen coverage. The circular cross sections of the CNTs were changed with different hydrogen coverage. When hydrogen is chemisorbed on the surface of the carbon nano tube, the energy gap will be appeared. This is due to the degree of the Sp 3 hybridization, and the hydrogen coverage can control the band gap of the carbon nano tube

  18. Preparation of tubular urease immobilized on the inner wall of glass tube by radiation-polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Y; Hayashi, T; Kawashima, K [National Food Research Inst., Yatabe, Ibaraki (Japan); Oka, O

    1981-03-01

    A method to prepare immobilized urease on the inner wall of a glass tube by radiation-polymerization under frozen state was investigated. As a part of a continuous flow analyzer, i.w.. Technicon Auto Analyzer II, the immobilized urease tube of 1 cm length was set and used for the routine determination of urea. This flow-through system could measure urea concentration of up to 30 mM at rate of 30 samples per hour. The system were possible to assay 2000 to 3000 samples, continuously in practice. The activity of the urease tube stored in a refrigerator maintained 94% of the initial activity after 115 days.

  19. Preparation of tubular urease immobilized on the inner wall of glass tube by radiation-polymerization

    International Nuclear Information System (INIS)

    Tanaka, Yoshikazu; Hayashi, Toru; Kawashima, Koji; Oka, Osamu.

    1981-01-01

    A method to prepare immobilized urease on the inner wall of a glass tube by radiation-polymerization under frozen state was investigated. As a part of a continuous flow analyzer, i.w.. Technicon Auto Analyzer II, the immobilized urease tube of 1 cm length was set and used for the routine determination of urea. This flow-through system could measure urea concentration of up to 30 mM at rate of 30 samples per hour. The system were possible to assay 2000 to 3000 samples, continuously in practice. The activity of the urease tube stored in a refrigirator maintained 94% of the initial activity after 115 days. (author)

  20. Calculation of nonstationary two-dimensional temperature field in a tube wall in burnout

    International Nuclear Information System (INIS)

    Kashcheev, V.M.; Pykhtina, T.V.; Yur'ev, Yu.S.

    1977-01-01

    Numerically solved is a nonstationary two-dimensional equation of heat conduction for a tube wall of fuel element simulator with arbitrary energy release. The tube is heat-insulated from the outside. The vapour-liquid mixture flows inside the tube. The burnout is realized, when the heat transfer coefficient corresponds to the developed boiling in one part of the tube, and to the deteriorated regime in the other part of it. The thermal losses are regarded on both ends of the tube. Given are the statement of the problem, the algorithm of the solution, the results of the test adjusting problem. Obtained is the satisfactory agreement of calculated fixed temperature with experimental one

  1. Heat transfer enhancement in a tube using circular cross sectional rings separated from wall

    International Nuclear Information System (INIS)

    Ozceyhan, Veysel; Gunes, Sibel; Buyukalaca, Orhan; Altuntop, Necdet

    2008-01-01

    A numerical study was undertaken for investigating the heat transfer enhancement in a tube with the circular cross sectional rings. The rings were inserted near the tube wall. Five different spacings between the rings were considered as p = d/2, p = d, p = 3d/2, p = 2d and p = 3d. Uniform heat flux was applied to the external surface of the tube and air was selected as working fluid. Numerical calculations were performed with FLUENT 6.1.22 code, in the range of Reynolds number 4475-43725. The results obtained from a smooth tube were compared with those from the studies in literature in order to validate the numerical method. Consequently, the variation of Nusselt number, friction factor and overall enhancement ratios for the tube with rings were presented and the best overall enhancement of 18% was achieved for Re = 15,600 for which the spacing between the rings is 3d

  2. Probability of a steam generator tube rupture due to the presence of axial through wall cracks

    International Nuclear Information System (INIS)

    Mavko, B.; Cizelj, L.

    1991-01-01

    Using the Leak-Before-Break (LBB) approach to define tube plugging criteria a possibility to operate with through wall crack(s) in steam generator tubes may be considered. This fact may imply an increase in tube rupture probability. Improved examination techniques (in addition to the 100% tube examination) have been developed and introduced to counterbalance the associated risk. However no estimates of the amount of total increase or decrease of risk due to the introduction of LBB have been made. A scheme to predict this change of risk is proposed in the paper, based on probabilistic fracture mechanics analysis of axial cracks combined with available data of steam generator tube nondestructive examination reliability. (author)

  3. Effects of Two Purification Pretreatments on Electroless Copper Coating over Single-Walled Carbon Nano tubes

    International Nuclear Information System (INIS)

    Zheng, Z.; Li, L.; Dong, Sh.; Li, Sh.; Xiao, A.; Sun, Sh.

    2014-01-01

    To achieve the reinforcement of copper matrix composite by single-walled carbon nano tubes, a three-step-refluxing purification of carbon nano tubes sample with HNO 3 -NaOH-HCl was proposed and demonstrated. A previously reported purification process using an electromagnetic stirring with H 2 O 2 /HCl mixture was also repeated. Then, the purified carbon nano tubes were coated with copper by the same electroless plating process. At the end, the effects of the method on carbon nano tubes themselves and on copper coating were determined by transmission electron microscope spectroscopy, scanning electron microscope spectroscopy, X-ray diffractometry, thermogravimetric analysis, Fourier transformed infrared spectroscopy, and energy dispersive spectrometry. It was clearly confirmed that both of the two processes could remove most of iron catalyst particles and carbonaceous impurities without significant damage to carbon nano tubes. The thermal stability of the sample purified by H 2 O 2 /HCl treatment was slightly higher than that purified by HNO 3 -NaOH-HCl treatment. Nevertheless, the purification by HNO 3 -NaOH-HCl treatment was more effective for carboxyl functionalization on nano tubes than that by H 2 O 2 /HCl treatment. The Cu-coating on carbon nano tubes purified by both purification processes was complete, homogenous, and continuous. However, the Cu-coating on carbon nano tubes purified by H 2 O 2 /HCl was oxidized more seriously than those on carbon nano tubes purified by HNO 3 -NaOH-HCl treatment.

  4. The thin-wall tube drift chamber operating in vacuum (prototype)

    Science.gov (United States)

    Alexeev, G. D.; Glonti, L. N.; Kekelidze, V. D.; Malyshev, V. L.; Piskun, A. A.; Potrbenikov, Yu. K.; Rodionov, V. K.; Samsonov, V. A.; Tokmenin, V. V.; Shkarovskiy, S. N.

    2013-08-01

    The goal of this work was to design drift tubes and a chamber operating in vacuum, and to develop technologies for tubes independent assembly and mounting in the chamber. These design and technology were tested on the prototype. The main features of the chamber are the following: the drift tubes are made of flexible mylar film (wall thickness 36 μm, diameter 9.80 mm, length 2160 mm) using ultrasonic welding along the generatrix; the welding device and methods were developed at JINR. Drift tubes with end plugs, anode wires and spacers were completely assembled outside the chamber. "Self-centering" spacers and bushes were used for precise setting of the anode wires and tubes. The assembled tubes were sealed with O-rings in their seats in the chamber which simplified the chamber assembling. Moreover the tube assembly and the chamber manufacture can be performed independently and in parallel; this sufficiently reduces the total time of chamber manufacture and assembling, its cost and allows tubes to be tested outside the chamber. The technology of independent tube assembling is suitable for a chamber of any shape but a round chamber is preferable for operation in vacuum. Single channel amplifier-discriminator boards which are more stable against cross talks were used for testing the tubes. Independently assembled tubes were mounted into the chamber prototype and its performance characteristic measured under the vacuum conditions. The results showed that both the structure and the tubes themselves normally operate. They are suitable for making a full-scale drift chamber for vacuum.

  5. The thin-wall tube drift chamber operating in vacuum (prototype)

    International Nuclear Information System (INIS)

    Alexeev, G.D.; Glonti, L.N.; Kekelidze, V.D.; Malyshev, V.L.; Piskun, A.A.; Potrbenikov, Yu.K.; Rodionov, V.K.; Samsonov, V.A.; Tokmenin, V.V.; Shkarovskiy, S.N.

    2013-01-01

    The goal of this work was to design drift tubes and a chamber operating in vacuum, and to develop technologies for tubes independent assembly and mounting in the chamber. These design and technology were tested on the prototype. The main features of the chamber are the following: the drift tubes are made of flexible mylar film (wall thickness 36 μm, diameter 9.80 mm, length 2160 mm) using ultrasonic welding along the generatrix; the welding device and methods were developed at JINR. Drift tubes with end plugs, anode wires and spacers were completely assembled outside the chamber. “Self-centering” spacers and bushes were used for precise setting of the anode wires and tubes. The assembled tubes were sealed with O-rings in their seats in the chamber which simplified the chamber assembling. Moreover the tube assembly and the chamber manufacture can be performed independently and in parallel; this sufficiently reduces the total time of chamber manufacture and assembling, its cost and allows tubes to be tested outside the chamber. The technology of independent tube assembling is suitable for a chamber of any shape but a round chamber is preferable for operation in vacuum. Single channel amplifier-discriminator boards which are more stable against cross talks were used for testing the tubes. Independently assembled tubes were mounted into the chamber prototype and its performance characteristic measured under the vacuum conditions. The results showed that both the structure and the tubes themselves normally operate. They are suitable for making a full-scale drift chamber for vacuum

  6. The thin-wall tube drift chamber operating in vacuum (prototype)

    Energy Technology Data Exchange (ETDEWEB)

    Alexeev, G.D. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Glonti, L.N., E-mail: glonti@sunse.jinr.ru [Joint Institute for Nuclear Research, Dubna (Russian Federation); Kekelidze, V.D.; Malyshev, V.L.; Piskun, A.A.; Potrbenikov, Yu.K.; Rodionov, V.K.; Samsonov, V.A.; Tokmenin, V.V.; Shkarovskiy, S.N. [Joint Institute for Nuclear Research, Dubna (Russian Federation)

    2013-08-01

    The goal of this work was to design drift tubes and a chamber operating in vacuum, and to develop technologies for tubes independent assembly and mounting in the chamber. These design and technology were tested on the prototype. The main features of the chamber are the following: the drift tubes are made of flexible mylar film (wall thickness 36 μm, diameter 9.80 mm, length 2160 mm) using ultrasonic welding along the generatrix; the welding device and methods were developed at JINR. Drift tubes with end plugs, anode wires and spacers were completely assembled outside the chamber. “Self-centering” spacers and bushes were used for precise setting of the anode wires and tubes. The assembled tubes were sealed with O-rings in their seats in the chamber which simplified the chamber assembling. Moreover the tube assembly and the chamber manufacture can be performed independently and in parallel; this sufficiently reduces the total time of chamber manufacture and assembling, its cost and allows tubes to be tested outside the chamber. The technology of independent tube assembling is suitable for a chamber of any shape but a round chamber is preferable for operation in vacuum. Single channel amplifier-discriminator boards which are more stable against cross talks were used for testing the tubes. Independently assembled tubes were mounted into the chamber prototype and its performance characteristic measured under the vacuum conditions. The results showed that both the structure and the tubes themselves normally operate. They are suitable for making a full-scale drift chamber for vacuum.

  7. Manufacture of thin-walled clad tubes by pressure welding of roll bonded sheets

    Science.gov (United States)

    Schmidt, Hans Christian; Grydin, Olexandr; Stolbchenko, Mykhailo; Homberg, Werner; Schaper, Mirko

    2017-10-01

    Clad tubes are commonly manufactured by fusion welding of roll bonded metal sheets or, mechanically, by hydroforming. In this work, a new approach towards the manufacture of thin-walled tubes with an outer diameter to wall thickness ratio of about 12 is investigated, involving the pressure welding of hot roll bonded aluminium-steel strips. By preparing non-welded edges during the roll bonding process, the strips can be zip-folded and (cold) pressure welded together. This process routine could be used to manufacture clad tubes in a continuous process. In order to investigate the process, sample tube sections with a wall thickness of 2.1 mm were manufactured by U-and O-bending from hot roll bonded aluminium-stainless steel strips. The forming and welding were carried out in a temperature range between RT and 400°C. It was found that, with the given geometry, a pressure weld is established at temperatures starting above 100°C. The tensile tests yield a maximum bond strength at 340°C. Micrograph images show a consistent weld of the aluminium layer over the whole tube section.

  8. Innovation in pressure tube life assessment

    International Nuclear Information System (INIS)

    Guler, B.; Kalenchuk, D.; Celovsky, A.

    2003-01-01

    The hydrogen equivalent concentration and the rate of hydrogen ingress (in particular, deuterium) in pressure tubes are important parameters that must be assessed to determine the fitness-for-service of CANDU reactors. This paper presents the latest refinement in a process referred to as 'Pressure Tube Sampling', which is the only fully qualified and proven method that allows accurate determination of both the hydrogen equivalent concentration and the rate deuterium ingress without performing an expensive fuel channel removal. Pressure Tube Sampling has evolved over the past fifteen years during which over 2,300 samples have been obtained from CANDU reactors around the globe. In-reactor sampling is the standard method for determining the hydrogen equivalent concentrations and deuterium ingress rates in CANDU reactors. Over the past fifteen years, continual improvements in the Pressure Tube Sampling process have resulted in: the capability to obtain circumferential and axial samples, reduced 'on-face' time, reduced cost, reduced dose to workers, and improved analysis accuracy. Most recently, the new Multi-Head Sampling Tool (MHST) has been developed that continues this trend by using one tool to sample at all four axial pressure tube locations in a single visit to the fuel channel, thereby further improving efficiency. In 2001 October, the MHST was successfully deployed at Wolsong 1 by AECL for Korea Hydro and Nuclear Power. The tool was delivered using their Advanced Delivery Machine (ADM) and a total of sixteen samples were obtained from four channels. A significant saving in time was achieved with a rate of one channel (four samples) being sampled every 2 1/2 hours. For a typical 10-channel campaign, this could equate to a 2 to 3 days time/saving, which is significant in terms of outage schedule, cost, and worker dose. This paper provides a description of some of the latest innovations, with specific details on site application, performance, and end results

  9. Structural and leakage integrity assessment of WWER steam generator tubes

    International Nuclear Information System (INIS)

    Splichal, K.; Otruba, J.; Keilova, E.; Krhounek, V.; Turek, J.

    1996-01-01

    The leakage and plugging limits were derived for WWER steam generators based on leak and burst tests using tubes with axial part-through and through-wall defects. The following conclusions were arrived at: (i) The permissible primary-to-secondary leak rate with respect to the permissible through-wall defect size of WWER-440 and WWER-1000 steam generator tubes is 8 l/h. (ii) The primary-to-secondary leak rate is reduced by the blocking of the tube cracks by corrosion product particles and other substances. (iii) The rate of crack penetration through the tube wall is higher than the crack widening. (iv) The validity of the criterion of instability for tubes with through-wall cracks was confirmed experimentally. For the WWER-440 and WWER-1000 steam generators, the critical size of axial through-wall cracks, for the threshold primary-to-secondary pressure difference, is 13.8 and 12.0 mm, respectively. (v) The calculated leakage for the rupture of one tube and for the assumed extreme defects is two orders and one order of magnitude, respectively, higher than the proposed primary water leakage limit of 8 l/h. (vi) The experiments gave evidence that the use of the permissible thinning limit of 80% for the heat exchange tube plugging does not bring about uncontrollable leakage or unstable crack growth. This is consistent with experience gained at WWER-440 type nuclear power plants. 4 tabs., 5 figs., 9 refs

  10. 76 FR 64312 - Light-Walled Welded Rectangular Carbon Steel Tubing From Taiwan: Final Results of the Expedited...

    Science.gov (United States)

    2011-10-18

    ... Rectangular Carbon Steel Tubing From Taiwan: Final Results of the Expedited Sunset Review of the Antidumping... the antidumping duty order on light-walled welded rectangular carbon steel tubing from Taiwan pursuant... steel tubing from Taiwan pursuant to section 751(c) of the Act. See Initiation of Five-Year (``Sunset...

  11. Antimicrobial Activity of Single-Walled Carbon Nano tubes Suspended in Different Surfactants

    International Nuclear Information System (INIS)

    Dong, L.; Alex Henderson, A.; Field, Ch.

    2012-01-01

    We investigated the antibacterial activity of single-walled carbon nano tubes (SWCNTs) dispersed in surfactant solutions of sodium cholate, sodium dodecylbenzene sulfonate, and sodium dodecyl sulfate. Among the three surfactants, sodium cholate demonstrated the weakest antibacterial activity against Salmonella enterica, Escherichia coli, and Enterococcus faecium and thereby was used to disperse bundled SWCNTs in order to study nano tube antibiotic activity. SWCNTs exhibited antibacterial characteristics for both S. enterica and E. coli. With the increase of nano tube concentrations from 0.3 mg/mL to 1.5 mg/mL, the growth curves had plateaus at lower absorbance values whereas the absorbance value was not obviously affected by the incubation ranging from 5?min to 2 h. Our findings indicate that carbon nano tubes could become an effective alternative to antibiotics in dealing with drug-resistant and multidrug-resistant bacterial strains because of the physical mode of bactericidal action that SWCNTs display

  12. Preparation of Multi-walled Carbon Nano tubes/ Natural Rubber Composite by Wet Mixing Method

    International Nuclear Information System (INIS)

    Azira Abdul Aziz; Azira Abdul Aziz; Che Su Mat Saad; Mohamad Rusop Mahmood

    2011-01-01

    Natural rubber/multi-walled carbon nano tubes (Nr/MWCNTs) nanocomposite is formed by incorporating nano tubes in a polymer solution and subsequently evaporating the solvent. Using this technique, nano tubes will be dispersed homogeneously in the NR matrix in an attempt to increase the mechanical properties of these nano composites. Mechanical test results show an increase in the tensile strength for up to 19 times in relation to pure NR. In addition to mechanical testing, the morphology of the MWNTs into NR was studied by Field Emission Scanning Electron Microscopy (FESEM) in order to understand the morphology of the resulting system. Slight shift noted from Raman analyses from each different wt. % of MWCNTs with the NR due to the stress transfer that indicates reinforcement of the nano tubes. (author)

  13. Axial Crushing Behaviors of Thin-Walled Corrugated and Circular Tubes - A Comparative Study

    Science.gov (United States)

    Reyaz-Ur-Rahim, Mohd.; Bharti, P. K.; Umer, Afaque

    2017-10-01

    With the help of finite element analysis, this research paper deals with the energy absorption and collapse behavior with different corrugated section geometries of hollow tubes made of aluminum alloy 6060-T4. Literature available experimental data were used to validate the numerical models of the structures investigated. Based on the results available for symmetric crushing of circular tubes, models were developed to investigate corrugated thin-walled structures behavior. To study the collapse mechanism and energy absorbing ability in axial compression, the simulation was carried in ABAQUS /EXPLICIT code. In the simulation part, specimens were prepared and axially crushed to one-fourth length of the tube and the energy diagram of crushing force versus axial displacement is shown. The effect of various parameters such as pitch, mean diameter, corrugation, amplitude, the thickness is demonstrated with the help of diagrams. The overall result shows that the corrugated section geometry could be a good alternative to the conventional tubes.

  14. Some aspects of metallurgical assessment of boiler tubes-Basic principles and case studies

    International Nuclear Information System (INIS)

    Chaudhuri, Satyabrata

    2006-01-01

    Microstructural changes in boiler tubes during prolong operation at high temperature and pressure decrease load bearing capacity limiting their useful lives. When the load bearing capacity falls below a critical level depending on operating parameters and tube geometry, failure occurs. In order to avoid such failures mainly from the view point of economy and safety, this paper describes some basic principles behind remaining life assessment of service exposed components and also a few case studies related to failure of a reheater tube of 1.25Cr-0.5Mo steel, a carbon steel tube and final superheater tubes of 2.25Cr-1Mo steel and remaining creep life assessment of service exposed but unfailed platen superheater and reheater tubes of 2.25Cr-1Mo steel. Sticking of fly ash particles causing reduction in effective tube wall thickness is responsible for failure of reheater tubes. Decarburised metal containing intergranular cracks at the inner surface of the carbon steel tube exhibiting a brittle window fracture is an indicative of hydrogen embrittlement responsible for this failure. In contrast, final superheater tube showed that the failure took place due to short-term overheating. The influence of prolong service revealed that unfailed reheater tubes exhibit higher tensile properties than that of platen superheater tubes. In contrast both the tubes at 50 MPa meet the minimum creep rupture properties when compared with NRIM data. The remaining creep life of platen superheater tube as estimated at 50 MPa and 570 deg. C (1058 o F) is more than 10 years and that of reheater tube at 50 MPa and 580 deg. C (1076 o F) is 9 years

  15. A new repair criterion for steam generator tubes with axial cracks based on probabilistic integrity assessment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun-Su; Oh, Chang-Kyun [KEPCO Engineering and Construction Company, Inc., 269, Hyeoksin-ro, Gimcheon, Gyeongsangbuk-do 39660 (Korea, Republic of); Chang, Yoon-Suk, E-mail: yschang@khu.ac.kr [Department of Nuclear Engineering, College of Engineering, Kyung Hee University, 1732 Deokyoungdaero, Giheung, Yongin, Gyeonggi 446-701 (Korea, Republic of)

    2017-03-15

    Highlights: • Probabilistic assessment was performed for axially cracked steam generator tubes. • The threshold crack sizes were determined based on burst pressures of the tubes. • A new repair criterion was suggested as a function of operation time. - Abstract: Steam generator is one of the major components in a nuclear power plant, and it consists of thousands of thin-walled tubes. The operating record of the steam generators has indicated that a number of axial cracks due to stress corrosion have been frequently detected in the tubes. Since the tubes are closely related to the safety and also the efficiency of a nuclear power plant, an establishment of the appropriate repair criterion for the defected tubes and its applications are necessary. The objective of this paper is to develop an accurate repair criterion for the tubes with axial cracks. To do this, a thorough review is performed on the key parameters affecting the tube integrity, and then the probabilistic integrity assessment is carried out by considering the various uncertainties. In addition, the sizes of critical crack are determined by comparing the burst pressure of the cracked tube with the required performance criterion. Based on this result, the new repair criterion for the axially cracked tubes is defined from the reasonably conservative value such that the required performance criterion in terms of the burst pressure is able to be met during the next operating period.

  16. Structural and leakage integrity assessment of WWER steam generator tubes

    Energy Technology Data Exchange (ETDEWEB)

    Splichal, K.; Otruba, J. [Nuclear Research Inst., Rez (Switzerland)

    1997-12-31

    The integrity of heat exchange tubes may influence the life-time of WWER steam generators and appears to be an important criterion for the evaluation of their safety and operational reliability. The basic requirement is to assure a very low probability of radioactive water leakage, preventing unstable crack growth and sudden tube rupture. These requirements led to development of permissible limits for primary to secondary leak evolution and heat exchange tubes plugging based on eddy current test inspection. The stress corrosion cracking and pitting are the main corrosion damage of WWER heat exchange tubes and are initiated from the outer surface. They are influenced by water chemistry, temperature and tube wall stress level. They take place under crevice corrosion condition and are indicated especially (1) under the tube support plates, where up to 90-95 % of defects detected by the ECT method occur, and (2) on free spans under tube deposit layers. Both the initiation and crack growth cause thinning of the tube wall and lead to part thickness cracks and through-wall cracks, oriented above all in the axial direction. 10 refs.

  17. Structural and leakage integrity assessment of WWER steam generator tubes

    International Nuclear Information System (INIS)

    Splichal, K.; Otruba, J.

    1997-01-01

    The integrity of heat exchange tubes may influence the life-time of WWER steam generators and appears to be an important criterion for the evaluation of their safety and operational reliability. The basic requirement is to assure a very low probability of radioactive water leakage, preventing unstable crack growth and sudden tube rupture. These requirements led to development of permissible limits for primary to secondary leak evolution and heat exchange tubes plugging based on eddy current test inspection. The stress corrosion cracking and pitting are the main corrosion damage of WWER heat exchange tubes and are initiated from the outer surface. They are influenced by water chemistry, temperature and tube wall stress level. They take place under crevice corrosion condition and are indicated especially (1) under the tube support plates, where up to 90-95 % of defects detected by the ECT method occur, and (2) on free spans under tube deposit layers. Both the initiation and crack growth cause thinning of the tube wall and lead to part thickness cracks and through-wall cracks, oriented above all in the axial direction

  18. Structural and leakage integrity assessment of WWER steam generator tubes

    Energy Technology Data Exchange (ETDEWEB)

    Splichal, K; Otruba, J [Nuclear Research Inst., Rez (Switzerland)

    1998-12-31

    The integrity of heat exchange tubes may influence the life-time of WWER steam generators and appears to be an important criterion for the evaluation of their safety and operational reliability. The basic requirement is to assure a very low probability of radioactive water leakage, preventing unstable crack growth and sudden tube rupture. These requirements led to development of permissible limits for primary to secondary leak evolution and heat exchange tubes plugging based on eddy current test inspection. The stress corrosion cracking and pitting are the main corrosion damage of WWER heat exchange tubes and are initiated from the outer surface. They are influenced by water chemistry, temperature and tube wall stress level. They take place under crevice corrosion condition and are indicated especially (1) under the tube support plates, where up to 90-95 % of defects detected by the ECT method occur, and (2) on free spans under tube deposit layers. Both the initiation and crack growth cause thinning of the tube wall and lead to part thickness cracks and through-wall cracks, oriented above all in the axial direction. 10 refs.

  19. Magnesium diboride on inner wall of copper tube: A test case for superconducting radio frequency cavities

    Directory of Open Access Journals (Sweden)

    Wenura K. Withanage

    2017-10-01

    Full Text Available Superconductor magnesium diboride is considered one of the viable materials to substitute bulk niobium for superconducting radio frequency cavities. Utilizing a MgB_{2} coating on the inner wall of a copper cavity will allow operation at higher temperatures (20–25 K than Nb cavities due to the high transition temperature of MgB_{2} (39 K and the high thermal conductivity of Cu. In this paper, we present results of MgB_{2} coating on Cu tubes with similar dimensions to a 3 GHz cavity, as the first step towards coating the actual cavity, using the hybrid physical chemical vapor deposition technique. The results show successful coating of a uniform MgB_{2} layer on the inner wall of the Cu tubes with T_{c} as high as 37 K.

  20. Magnesium diboride on inner wall of copper tube: A test case for superconducting radio frequency cavities

    Science.gov (United States)

    Withanage, Wenura K.; Lee, N. H.; Penmatsa, Sashank V.; Wolak, M. A.; Nassiri, A.; Xi, X. X.

    2017-10-01

    Superconductor magnesium diboride is considered one of the viable materials to substitute bulk niobium for superconducting radio frequency cavities. Utilizing a MgB2 coating on the inner wall of a copper cavity will allow operation at higher temperatures (20-25 K) than Nb cavities due to the high transition temperature of MgB2 (39 K) and the high thermal conductivity of Cu. In this paper, we present results of MgB2 coating on Cu tubes with similar dimensions to a 3 GHz cavity, as the first step towards coating the actual cavity, using the hybrid physical chemical vapor deposition technique. The results show successful coating of a uniform MgB2 layer on the inner wall of the Cu tubes with Tc as high as 37 K.

  1. The influence of triggers geometry upon the stiffness of cylindrical thin walled tubes

    Science.gov (United States)

    Soica, Adrian; Radu, Gheorghe N.

    2014-06-01

    Today's automobile manufacturers are increasingly using lightweight materials to reduce weight; these include plastics, composites, aluminium, magnesium alloys, and also new types of high strength steels. Many of these materials have limited strength or ductility, therefore in many cases the rupture being serious consequences during crashes, underscore Picketta et al. in their studies. Automotive structures must deform plastically in a short period of time, a few milliseconds, to absorb the crash energy in a controllable manner. It must be light and enable economically mass-production [1]. FE models rapidly gained acceptance among engineers. Many other factors facilitated the development of vehicle models by shell finite elements since most of the geometry of the structural surfaces was already on computer graphic files. Kee Poong Kim and Hoon Huh emphasize that the crashworthiness of each vehicle part needs to be evaluated at the initial stage of design for good performance of an assembled vehicle. As the dynamic behaviour of structural members is different from the static one, the crashworthiness of the vehicle structures has to be assessed by impact analysis. The paper analyzes the influence of trigger geometry upon the compression of thin-walled cylindrical tubes. Simulations performed on a simple model showed the dependence between triggers area and deformation times as well as the maximum deformations obtained for various speeds at which the simulations ware carried out. Likewise, the geometry of trigger leads to different results.

  2. Numerical simulation of heat fluxes in a two-temperature plasma at shock tube walls

    International Nuclear Information System (INIS)

    Kuznetsov, E A; Poniaev, S A

    2015-01-01

    Numerical simulation of a two-temperature three-component Xenon plasma flow is presented. A solver based on the OpenFOAM CFD software package is developed. The heat flux at the shock tube end wall is calculated and compared with experimental data. It is shown that the heat flux due to electrons can be as high as 14% of the total heat flux. (paper)

  3. Numerical simulation of heat fluxes in a two-temperature plasma at shock tube walls

    Science.gov (United States)

    Kuznetsov, E. A.; Poniaev, S. A.

    2015-12-01

    Numerical simulation of a two-temperature three-component Xenon plasma flow is presented. A solver based on the OpenFOAM CFD software package is developed. The heat flux at the shock tube end wall is calculated and compared with experimental data. It is shown that the heat flux due to electrons can be as high as 14% of the total heat flux.

  4. Multi-walled carbon nano-tubes for energy storage and production applications

    International Nuclear Information System (INIS)

    Andrews, R.; Jacques, D.; Likpa, S.; Qian, D.; Rantell, T.; Anthony, J.

    2005-01-01

    Full text of publication follows: Since their discovery, carbon nano-tubes have been proposed as candidate materials for a broad range of applications, including high strength composites, molecular electronics, and energy storage. In many cases, nano-tubes have been proposed to replace traditional carbon materials, such as activated carbons in energy storage devices. In other cases, novel applications have been proposed, such as the use of carbon nano-tube arrays in photovoltaic devices. The use of multi-walled carbon nano-tubes in energy storage devices has generated great interest due to their high inherent conductivity, layered structure, and high surface area per volume compared to traditional graphitic materials. However as produced nano-tubes do not possess ideal properties, and exhibit only modest charge storage. We have explored the charge storage abilities of nano-tubes with varying morphologies (fullerenic versus stacked cones), nano-tubes containing N or B dopants, as well as various post-treatments of the nano-tubes. The use of nano-tubes in charge storage devices will be described, as well as modification of the nano-tube surfaces or morphology to improve this performance. The synthesis of nano-tubes with several differing hetero-atom dopants will also be described, as well as the effect of heat treatment on these structures. One of the most significant problems in organic photovoltaics is the typically low charge-carrier mobility in organic thin films which, coupled with short exciton diffusion lengths, means that photo-generated charge-carrier pairs are more likely to re-combine than reach an electrode to generate current. Two organic systems with high charge-carrier mobilities are carbon nano-tubes (here, MWNTs) and acene-based organic semiconductors. We believe that blended devices based on MWNTs and organic semiconductors could lead to the next class of efficient, flexible and inexpensive organic photovoltaic systems. We have developed methods to

  5. Ultrasonic wall thickness gauging for ferritic steam generator tubing as an in-service inspection tool

    International Nuclear Information System (INIS)

    Haesen, W.M.J.; Tromp, Th.J.

    1980-01-01

    In-service inspection of LWR steam generators is more or less a standard routine operation. The situation can be very different for LMFBRs. For the SNR 300 (Kalkar Power Station) the situation is different because the steam generators have ferritic tubing. The tube walls are comparatively thick, 2 to 4.5 mm. During inservice examinations the steam generators will be drained on both sides, however on the sodium side a sodium film will be present. Furthermore the SNR 300 will have two types of steam generator. A straight tube design and a helical coil design will be used. Both types consist of a evaporator and superheater. The steam generators are of course not radioactive. It is obvious that in this case the eddy current (EC) technique is not an enviable inservice inspection tool. Basically EC is a surface flaw detection technique. Only the saturation magnetisation method will improve the EC technique sufficiently for ferritic material. However the 'in bore examination' with the saturation technique was, in case of the SNR 300 steam generator tubing, considered impossible since the inner diameters are fairly small. Furthermore sodium traces may influence the EC method. Although multifrequency methods can solve this problem, EC is not considered as a useful tool for examining ferritic tubing. Another method is to employ the 'stray flux' method which is under development with the TNO organization in Holland. The EC and stray flux method do have one drawback, these methods do not detect gradual changes in wall thickness. Ultrasonic examinations will be used in the SNR 300 as the main inspection tool for the steam generators. In this paper the reasons why ultrasonic examination was selected are explained. The results of the development work on this subject are discussed

  6. Laminar free convection in a vertical tube with constant wall temperature considering the variation of fluid properties

    International Nuclear Information System (INIS)

    Senna, J.G.

    1981-01-01

    A model to analyze Laminar Free convection with variable properties in the entrance of a vertical open tube with constant wall temperature and for one Prandtl number (0.7), is studied. The velocity and temperature profiles are determined by finite difference methods for different rates of wall to ambient temperatures and different values of the velocity in the entrance of the tube. The results will be compared with those obtained in the same problem with constant properties. (Author) [pt

  7. Dissecting the regulation of pollen tube growth by modelling the interplay of hydrodynamics, cell wall and ion dynamics

    Directory of Open Access Journals (Sweden)

    Junli eLiu

    2014-08-01

    Full Text Available Hydrodynamics, cell wall and ion dynamics are all important properties that regulate pollen tube growth. Currently, the two main pollen tube growth models, the cell wall model and the hydrodynamic model do not appear to be reconcilable. Here we develop an integrative model for pollen tube growth and show that our model reproduces key experimental observations: 1 that the hypertonic condition leads to a much longer oscillatory period and that the hypotonic condition halves the oscillatory period; 2 that oscillations in turgor are experimentally undetectable; 3 that increasing the extracellular calcium concentration or decreasing the pH decreases the growth oscillatory amplitude; 4 that knockout of Raba4d, a member of the Rab family of small GTPase proteins, decreases pollen tube length after germination for 24 hours. Using the model generated here, we reveal that 1 when cell wall extensibility is large, pollen tube may sustain growth at different volume changes and maintain relatively stable turgor; 2 turgor increases if cell wall extensibility decreases; 3 increasing turgor due to decrease in osmolarity in the media, although very small, increases volume change . However, increasing turgor due to decrease in cell wall extensibility decreases volume change. In this way regulation of pollen tube growth by turgor is context dependent. By changing the osmolarity in the media, the main regulatory points are extracellular osmolarity for water flow and turgor for the volume encompassed by the cell wall. However, if the viscosity of cell wall changes, the main regulatory points are turgor for water flow and wall extensibility for the volume encompassed by the cell wall. The novel methodology developed here reveals the underlying context-dependent regulatory principle of pollen tube growth.

  8. Comparative assessment of condensation models for horizontal tubes

    International Nuclear Information System (INIS)

    Schaffrath, A.; Kruessenberg, A.K.; Lischke, W.; Gocht, U.; Fjodorow, A.

    1999-01-01

    The condensation in horizontal tubes plays an important role e.g. for the determination of the operation mode of horizontal steam generators of VVER reactors or passive safety systems for the next generation of nuclear power plants. Two different approaches (HOTKON and KONWAR) for modeling this process have been undertaken by Forschungszentrum Juelich (FZJ) and University for Applied Sciences Zittau/Goerlitz (HTWS) and implemented into the 1D-thermohydraulic code ATHLET, which is developed by the Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH for the analysis of anticipated and abnormal transients in light water reactors. Although the improvements of the condensation models are developed for different applications (VVER steam generators - emergency condenser of the SWR1000) with strongly different operation conditions (e.g. the temperature difference over the tube wall in HORUS is up to 30 K and in NOKO up to 250 K, the heat flux density in HORUS is up to 40 kW/m 2 and in NOKO up to 1 GW/m 2 ) both models are now compared and assessed by Forschungszentrum Rossendorf FZR e.V. Therefore, post test calculations of selected HORUS experiments were performed with ATHLET/KONWAR and compared to existing ATHLET and ATHLET/HOTKON calculations of HTWS. It can be seen that the calculations with the extension KONWAR as well as HOTKON improve significantly the agreement between computational and experimental data. (orig.) [de

  9. 77 FR 5240 - Light-Walled Welded Rectangular Carbon Steel Tubing From Taiwan: Continuation of Antidumping Duty...

    Science.gov (United States)

    2012-02-02

    ... Rectangular Carbon Steel Tubing From Taiwan: Continuation of Antidumping Duty Order AGENCY: Import... revocation of the antidumping duty order on light-walled welded rectangular carbon steel tubing from Taiwan would likely lead to a continuation or recurrence of dumping and material injury to an industry in the...

  10. Thin chest wall is an independent risk factor for the development of pneumothorax after chest tube removal.

    Science.gov (United States)

    Anand, Rahul J; Whelan, James F; Ferrada, Paula; Duane, Therese M; Malhotra, Ajai K; Aboutanos, Michel B; Ivatury, Rao R

    2012-04-01

    The factors contributing to the development of pneumothorax after removal of chest tube thoracostomy are not fully understood. We hypothesized that development of post pull pneumothorax (PPP) after chest tube removal would be significantly lower in those patients with thicker chest walls, due to the "protective" layer of adipose tissue. All patients on our trauma service who underwent chest tube thoracostomy from July 2010 to February 2011 were retrospectively reviewed. Patient age, mechanism of trauma, and chest Abbreviated Injury Scale score were analyzed. Thoracic CTs were reviewed to ascertain chest wall thickness (CW). Thickness was measured at the level of the nipple at the midaxillary line, as perpendicular distance between skin and pleural cavity. Chest X-ray reports from immediately prior and after chest tube removal were reviewed for interval development of PPP. Data are presented as average ± standard deviation. Ninety-one chest tubes were inserted into 81 patients. Patients who died before chest tube removal (n = 11), or those without thoracic CT scans (n = 13) were excluded. PPP occurred in 29.9 per cent of chest tube removals (20/67). When PPP was encountered, repeat chest tube was necessary in 20 per cent of cases (4/20). After univariate analysis, younger age, penetrating mechanism, and thin chest wall were found to be significant risk factors for development of PPP. Chest Abbreviated Injury Scale score was similar in both groups. Logistic regression showed only chest wall thickness to be an independent risk factor for development of PPP.

  11. 76 FR 33200 - Light-Walled Rectangular Pipe and Tube from Turkey; Notice of Preliminary Results of Antidumping...

    Science.gov (United States)

    2011-06-08

    ...) metallic coating; (3) painted/non-painted; (4) perimeter; (5) wall thickness; and (6) shape. See the... pipe and tube from Turkey. Atlas Tube, Inc. and Searing Industries, Inc. are petitioners in this case... through April 2010. Our analysis indicated, based on record evidence, that the appropriate date of sale of...

  12. Anharmonic properties of Raman modes in double wall carbon nano tubes

    Energy Technology Data Exchange (ETDEWEB)

    Marquina, J. [Universidad de los Andes, Facultad de Ciencias, Centro de Estudios Avanzados en Optica, 5101 Merida (Venezuela, Bolivarian Republic of); Power, Ch.; Gonzalez, J. [Universidad de los Andes, Facultad de Ciencias, Centro de Estudios en Semiconductores, 5101 Merida (Venezuela, Bolivarian Republic of); Broto, J. M. [Universite de Toulouse, Laboratoire National des Champs Magnetiques Intenses, CNRS UPR 3228, 31400 Toulouse (France); Flahaut, E., E-mail: castella@ula.v [Universite Paul Sabatier, Laboratoire de Chimie des Materiaux Inorganiques, UMR CNRS 5085, 31062 Toulouse (France)

    2011-07-01

    The temperature dependence of the radial breathing modes (RB Ms) and the zone-center tangential optical phonons (G-bands) of double-walled carbon nano tubes has been investigated between 300 and 700 K using Raman scattering. As expected, with increasing temperature, the frequencies of the Raman peaks, including the RB Ms and G-bands downshift simultaneously. We show here that the temperature dependence of the RB Ms can be fitted by a simple linear dependence and different RB Ms have different frequency shifts. We observe a noticeable nonlinearity in the temperature dependence of the G-band associated with the outer semiconducting tube G+ext (s). The deviation from the linear trend is due to the contribution of the third-order anharmonic term in the lattice potential energy with a pure temperature effect. An estimated value of 1.5 for the Grueneisen parameter of the G+ext (s) band was found. (Author)

  13. A study of cladding technology on tube wall surface by a hand-held laser torch

    International Nuclear Information System (INIS)

    Terada, Takaya; Nishimura, Akihiko; Oka, Kiyoshi; Moriyama, Taku; Matsuda, Hiroyasu

    2015-01-01

    New maintenance technique was proposed using a hand-held laser torch for aging chemical plants and power plants. The hand-held laser torch was specially designed to be able to access limited tubular space in various cases. A composite-type optical fiberscope was composed of a center fiber for beam delivery and surrounded fibers for visible image delivery. Laser irradiation on a work pieces with the best accuracy of filler wire was carried out. And, we found that the optimized wire-feed speed was 2 mm/s in laser cladding. We succeeded to make a line clad on the inner wall of 23 mm tube. This technique was discussed to be applied to the maintenance for cracks or corrosions of tubes in various harsh environments. (author)

  14. Modelling complex draft-tube flows using near-wall turbulence closures

    Energy Technology Data Exchange (ETDEWEB)

    Ventikos, Y.; Sotiropoulos, F. [Georgia Institute of Technology, Atlanta, GA (United States). School of Civil and Environmental Engineering; Patel, V.C. [Univ. of Iowa, Iowa City, IA (United States). Iowa Institute of Hydraulic Research

    1996-12-31

    This paper presents a finite-volume method for simulating flows through complex hydroturbine draft-tube configurations using near-wall turbulence closures. The method employs the artificial-compressibility pressure-velocity coupling approach in conjunction with multigrid acceleration for fast convergence on very fine grids. Calculations are carried out for a draft tube with two downstream piers on a computational mesh consisting of 1.2x10{sup 6} nodes. Comparisons of the computed results with measurements demonstrate the ability of the method to capture most experimental trends with reasonable accuracy. Calculated three-dimensional particle traces reveal very complex flow features in the vicinity of the piers, including horse-shoe longitudinal vortices and and regions of flow reversal.

  15. Studies on transport phenomena in polymer solutions and suspensions flowing through tubes of tortuous wall geometry

    Science.gov (United States)

    Narayanan, C. M.

    2014-02-01

    Attempts have been made to analyse the momentum and heat transfer characteristics in tortuous flow of non-Newtonian fluids such as suspensions and polymer solutions through tubes of diverging-converging geometry. The results of the study indicate that the transfer coefficients are significantly higher in such systems as compared to the conventional couette flow (through uniform cylindrical tubes). Moreover, the simultaneous increase in pressure drop due to the tortuous wall geometry has been observed to be relatively insignificant. Fluids with different rheological characteristics such as Bingham plastic fluids, pseudoplastic fluids, Ellis model fluids and fluids obeying Reiner-Philippoff rheology have been studied. The specific advantages of these geometries in providing enhanced performance efficiency have been effectively highlighted.

  16. Development of an ECT technique for discriminating between a through-wall/non through-wall crack in a steam generator tube

    International Nuclear Information System (INIS)

    Lee, D.H.; Choi, M.S.; Hur, D.H.; Han, J.H.; Lee, U.C.

    2004-01-01

    In a lot of pressurized water reactors, PWSCC (primary water stress corrosion cracking) has been observed in the expansion or u-bend transitions of the alloy 600 steam generator tubes. Particularly, the development of a through-wall crack may cause leakage of the primary coolant during operation and the resultant forced outage, and the in-situ pressure test has often been used to evaluate the integrity and the leakage of the cracked tube during an in-service inspection. However, this process requires additional equipment and hours, and the tested tubes are plugged due to the plastic deformation induced by the internal pressurization. This paper describes a new evaluation technique of the Eddy current test, by which it can be determined whether the crack is through-wall or non through-wall. The technique is based upon the analysis of the characteristics in the Eddy current signals from the crack and also includes the method of measuring exact through-wall length of the crack. The proof and applicability of the technique is discussed with the results of the destructive tests on cracked tubes extracted from a commercial power plant. Also, the effect of crack opening, which reflects the driving force for a crack propagation of non through-wall crack and the leak rate of a through-wall crack, upon the characteristics of the Eddy current signals from the coils of the motorized rotating probe is investigated and discussed using steam generator tube samples with manufactured axial cracks of a through-wall and non through-wall. (orig.)

  17. Condition monitoring and life assessment of lake water cooled admiralty brass condenser tubes of a nuclear power plant

    International Nuclear Information System (INIS)

    De, P.K.; Ghosal, S.K.; Kutty, K.K.; Bhat, H.R.

    2000-01-01

    The present paper deals with the failure of condenser tubes in a nuclear power plant. The tubes were made of arsenical admiralty brass and were cooled using lake water. They were in service for over 25 years. So far about 1000 tubes have been plugged as they failed due to several reasons. In order to assess the remaining life of the existing tubes as well as to investigate the cause of recent tube failures, some of the tubes from the condenser were removed and examined in detail following several procedure. It was observed that in general, wall thickness of the tubes was reduced by 10- 15%. Maximum reduction in wall thickness took place near the water inlet ends. No denting type phenomenon was observed at the tube to tube-support plate crevice locations. At certain locations on ID surfaces of some tubes, small steps, 0.2 mm high, were noticed along the longitudinal direction of the tubes. ID surfaces of the tubes were covered with light gray coloured thin and adherent corrosion products decorated with red spots at places. EDAX analysis showed that these red spots were enriched with copper. While some pits were present on the ID surfaces, the OD surfaces were covered with shining black oxide film. Fracture surfaces of the tubes, which had lost much strength and broke while taking them out of the condenser, showed presence of cleavages with fatigue striations near the OD edges. Mechanical properties of the tubes as such had deteriorated significantly. The tubes were observed to have been degraded to a large extent due to localised corrosion on the ID surfaces and corrosion fatigue damage caused by flow induced vibration. Under the present operational conditions, the tubes are expected to perform satisfactorily for a limited period. (author)

  18. Development of on-line wall thickness gauge for small size seamless tube. Shokei seamless netsukan nikuatsukei no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Okumura, T; Konya, N; Oka, H; Kasuya, T [Kawasaki Steel Corp., Tokyo (Japan)

    1991-03-01

    In order to heighten the accuracy of small size seamless tube wall thickness, hot wall thickness gauge was developed to be installed, immediately behind the finishing/rolling mill, for the on-line measurement, of which the method was by the parallel-beam transmissivity of gamma-ray. The measurement unit, aiming at flexible manufacturing system (FMS), is completely automated in correcting the accuracy, changing the sizes, etc. The damping characteristics of gamma-ray beam can be expressed by a characteristic function, taking the outside diameter and wall thickness of subject tube as parameters. The functional calculation, as based on measurement of transmitted quantity of gamma-ray through the three-dimensional steel material, changes, depending upon the outside diameter, wall thickness and material specification of subject tube. System was so applied as to calculate it therefore on a case-by-case basis. Though in the vicinity of tube end, the transmitted quantity of gamma-ray is largely influenced by the horizontal dislocation, that influence is slack in the middle part of tube. Therefore, the cross sectional division was made dense and sparse in the end part and middle part, respectively of tube, which division could diminish the error from several percent to less than 0.1%. The static noise was compressed by the optimized digital filter. That gauge is presently applied for the operational administration of small size seamless tube rolling. 2 refs., 11 figs., 2 tabs.

  19. Vortical and acoustical mode coupling inside a porous tube with uniform wall suction.

    Science.gov (United States)

    Jankowskia, T A; Majdalani, J

    2005-06-01

    This paper considers the oscillatory motion of gases inside a long porous tube of the closed-open type. In particular, the focus is placed on describing an analytical solution for the internal acoustico-vortical coupling that arises in the presence of appreciable wall suction. This unsteady field is driven by longitudinal oscillatory waves that are triggered by small unavoidable fluctuations in the wall suction speed. Under the assumption of small amplitude oscillations, the time-dependent governing equations are linearized through a regular perturbation of the dependent variables. Further application of the Helmholtz vector decomposition theorem enables us to discriminate between acoustical and vortical equations. After solving the wave equation for the acoustical contribution, the boundary-driven vortical field is considered. The method of matched-asymptotic expansions is then used to obtain a closed-form solution for the unsteady momentum equation developing from flow decomposition. An exact series expansion is also derived and shown to coincide with the numerical solution for the problem. The numerically verified end results suggest that the asymptotic scheme is capable of providing a sufficiently accurate solution. This is due to the error associated with the matched-asymptotic expansion being smaller than the error introduced in the Navier-Stokes linearization. A basis for comparison is established by examining the evolution of the oscillatory field in both space and time. The corresponding boundary-layer behavior is also characterized over a range of oscillation frequencies and wall suction velocities. In general, the current solution is found to exhibit features that are consistent with the laminar theory of periodic flows. By comparison to the Sexl profile in nonporous tubes, the critically damped solution obtained here exhibits a slightly smaller overshoot and depth of penetration. These features may be attributed to the suction effect that tends to

  20. Technical note: Influence of surface roughness and local turbulence on coated-wall flow tube experiments for gas uptake and kinetic studies

    Directory of Open Access Journals (Sweden)

    G. Li

    2018-02-01

    individual flow tube experiment. We use coating thickness values from previous coated-wall flow tube studies to assess potential roughness effects using the δc criterion. In most studies, the coating thickness was sufficiently small to avoid complications, but some may have been influenced by surface roughness and local turbulence effects.

  1. SPECIAL PURPOSE SHOCK TUBE for BLAST ASSESSMENT

    Data.gov (United States)

    Federal Laboratory Consortium — This device is a specially designed shock tube for testing fabric samples in a controlled environment. The device determines the appropriate types of sensors to be...

  2. Integrated probabilistic assessment for DHC initiation, growth and leak-before-break of PHWR pressure tubes

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Young-Jin [Power Engineering Research Institute, KEPCO Engineering and Construction, 188 Gumi-dong, Bundang-gu, Seongnam-si, Gyeonggi-do 463-870 (Korea, Republic of); Chang, Yoon-Suk, E-mail: yschang@khu.ac.kr [Department of Nuclear Engineering, Kyung Hee University, 1732 Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 446-701 (Korea, Republic of)

    2014-08-15

    Highlights: • We develop an integrated approach for probabilistic assessment of PHWR pressure tube. • We examine probabilities of DHC initiation, growth, penetration and LBB failure. • The proposed approach is helpful to calculate rupture probabilities in reactor flaws even in the case of very low rupture probability. - Abstract: A few hundred zirconium alloy pressure tubes in a pressurized heavy water reactor (PHWR) serve as the nuclear fuel channel, as well as the reactor coolant pressure boundary. The pressure tubes are inspected periodically and a fitness-for-service assessment (FFSA) must be conducted if any flaw is detected in the inspection. A Canadian standard provides FFSA procedures of PHWR pressure tubes, which include probabilistic assessment for flaws considering delayed hydride cracking (DHC) and leak-before-break (LBB). In the present study, an integrated approach with detailed stepwise calculation procedures and integration methodology for probabilistic assessment of pressure tube was developed. In the first step of this approach, a probability of the DHC initiation, growth and penetration for single initial flaw is calculated. In the next step, a probability of LBB failure, which means tube rupture, for single through-wall crack (TWC) is calculated. Finally, a rupture probability for all initial flaws in a reactor can be calculated using the penetration probability for single flaw and the LBB failure probability for single TWC, as well as the predicted total number of initial flaw in the reactor.

  3. Integrated probabilistic assessment for DHC initiation, growth and leak-before-break of PHWR pressure tubes

    International Nuclear Information System (INIS)

    Oh, Young-Jin; Chang, Yoon-Suk

    2014-01-01

    Highlights: • We develop an integrated approach for probabilistic assessment of PHWR pressure tube. • We examine probabilities of DHC initiation, growth, penetration and LBB failure. • The proposed approach is helpful to calculate rupture probabilities in reactor flaws even in the case of very low rupture probability. - Abstract: A few hundred zirconium alloy pressure tubes in a pressurized heavy water reactor (PHWR) serve as the nuclear fuel channel, as well as the reactor coolant pressure boundary. The pressure tubes are inspected periodically and a fitness-for-service assessment (FFSA) must be conducted if any flaw is detected in the inspection. A Canadian standard provides FFSA procedures of PHWR pressure tubes, which include probabilistic assessment for flaws considering delayed hydride cracking (DHC) and leak-before-break (LBB). In the present study, an integrated approach with detailed stepwise calculation procedures and integration methodology for probabilistic assessment of pressure tube was developed. In the first step of this approach, a probability of the DHC initiation, growth and penetration for single initial flaw is calculated. In the next step, a probability of LBB failure, which means tube rupture, for single through-wall crack (TWC) is calculated. Finally, a rupture probability for all initial flaws in a reactor can be calculated using the penetration probability for single flaw and the LBB failure probability for single TWC, as well as the predicted total number of initial flaw in the reactor

  4. Simultaneous and long-lasting hydrophilization of inner and outer wall surfaces of polytetrafluoroethylene tubes by transferring atmospheric pressure plasmas

    International Nuclear Information System (INIS)

    Chen, Faze; Song, Jinlong; Huang, Shuai; Xu, Wenji; Sun, Jing; Liu, Xin; Xu, Sihao; Xia, Guangqing; Yang, Dezheng

    2016-01-01

    Plasma hydrophilization is a general method to increase the surface free energy of materials. However, only a few works about plasma modification focus on the hydrophilization of tube inner and outer walls. In this paper, we realize simultaneous and long-lasting plasma hydrophilization on the inner and outer walls of polytetrafluoroethylene (PTFE) tubes by atmospheric pressure plasmas (APPs). Specifically, an Ar atmospheric pressure plasma jet (APPJ) is used to modify the PTFE tube’s outer wall and meanwhile to induce transferred He APP inside the PTFE tube to modify its inner wall surface. The optical emission spectrum (OES) shows that the plasmas contain many chemically active species, which are known as enablers for various applications. Water contact angle (WCA) measurements, x-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) are used to characterize the plasma hydrophilization. Results demonstrate that the wettability of the tube walls are well improved due to the replacement of the surface fluorine by oxygen and the change of surface roughness. The obtained hydrophilicity decreases slowly during more than 180 d aging, indicating a long-lasting hydrophilization. The results presented here clearly demonstrate the great potential of transferring APPs for surface modification of the tube’s inner and outer walls simultaneously. (paper)

  5. Guidelines for Selecting Plugs Used in Thin-Walled Tube Drawing Processes of Metallic Alloys

    Directory of Open Access Journals (Sweden)

    Eva María Rubio

    2017-12-01

    Full Text Available In this paper, some practical guidelines to select the plug or set of plugs more adequate to carry out drawing processes of thin-walled tubes carried out with fixed conical inner plug are presented. For this purpose, the most relevant input parameters have been considered in this study: the tube material, the most important geometrical parameters of the process (die semiangle, α , and cross-sectional area reduction, r and the friction conditions (Coulomb friction coefficients, μ 1 , between the die and the tube outer surface, and μ 2 , between the plug and the tube inner surface. Three work-hardening materials are analyzed: the annealed copper UNS C11000, the aluminum UNS A91100, and the stainless steel UNS S34000. The analysis is realized by means of the upper bound method (UBM, modelling the plastic deformation zone by triangular rigid zones (TRZ, under the validated assumption that the process occurs under plane strain conditions. The obtained results allow establishing, for each material, a group of geometrical parameters, friction conditions, a set of plugs that make possible to carry out the process under good conditions, and the optimum plug to carry out the process using the minimum amount of energy. The proposed model is validated by means of an own finite element analysis (FEA carried out under different conditions and, in addition, by other finite element method (FEM simulations and real experiments taken from other researchers found in the literature (called literature simulations and literature experimental results, respectively. As a main conclusion, it is possible to affirm that the plug that allows carrying out the process with minimum quantity of energy is cylindrical in most cases.

  6. Low-cost fabrication of thin-walled solid electrolyte tubes from doctor-bladed ceramic tape

    Energy Technology Data Exchange (ETDEWEB)

    Dirstine, R T

    1979-01-01

    Sodium ..beta..-Al/sub 2/O/sub 3/ tubes having wall thicknesses of typically 0.4 mm were fabricated from doctor-bladed (cast) ceramic tape by use of proprietary organic slip compositions and zeta-processed, lithia-stabilized alumina power. The ceramic tubes fabricated from cast tape had low porosity, low resistivity (approx. 4 ohm-cm at 300/sup 0/C), and good mechanical strength. Alternative fabrication techniques for manufacture of tubes from tape were evaluated, and the primary processing requirements/obstacls were identified. Closed-end tubes, nominally 10 mm outer diameter, 60 mm in length, and with a wall thickness of 0.3 mm, were supplied to the Department of Energy. 26 figures, 10 tables.

  7. Electrophoretic deposition (EPD) of multi-walled carbon nano tubes (MWCNT) onto indium-tin-oxide (ITO) glass substrates

    International Nuclear Information System (INIS)

    Mohd Roslie Ali; Shahrul Nizam Mohd Salleh

    2009-01-01

    Full text: Multi-Walled Carbon Nano tubes (MWCNT) were deposited onto Indium-Tin-Oxide (ITO)-coated glass substrates by introducing the use of Electrophoretic Deposition (EPD) as the method. The Multi-Walled Carbon Nano tubes (MWCNT) were dispersed ultrasonically in ethanol and sodium hydroxide (NaOH) to form stable suspension. The addition of Sodium Hydroxide in ethanol can stabilize the suspension, which was very important step before the deposition take place. Two substrates of Indium-Tin-Oxide(ITO)-coated glass placed in parallel facing each other (conductive side) into the suspension. The deposition occurs at room temperature, which the distance fixed at 1 cm between both electrodes and the voltage level applied was fixed at 400 V, respectively. The deposition time also was fixed at 30 minutes. The deposited ITO-Glass with Multi-Walled Carbon Nano tubes (MWCNT) will be characterized using Scanning Electron Microscope (SEM), Atomic Force Microscope (AFM), and Raman Microscope. The images of SEM shows that the Multi -Walled Carbon Nano tubes (MWCNT) were distributed uniformly onto the surface of ITO-Glass. The deposited ITO-Glass with Multi-Walled Carbon Nano tubes (MWCNT) could be the potential material in various practical applications such as field emission devices, fuel cells, and super capacitors. Electrophoretic deposition (EPD) technique was found to be an efficient technique in forming well distribution of Multi-Walled Carbon Nano tubes (MWCNT) onto ITO-Glass substrates, as proved in characterization methods, in which the optimum conditions will play the major role. (author)

  8. Thick-walled anisotropic elliptic tube analyzed via curvilinear tensor calculus

    Directory of Open Access Journals (Sweden)

    Mareš T.

    2007-10-01

    Full Text Available After a brief introduction into the tensor calculus, the thick-walled anisotropic elliptic tube is analyzed. A procedure of the analysis is described in a stepwise manner. A choice of the appropriate coordinate systems is the first step. The second step consists of the determination of corresponding metric tensors. Then the elasticity tensor of a local orthotropy is transformed into a global computational coordinate system. Next the appropriate Christoffel symbols of the second kind are determined and the total potential energy of the system is expressed. At the end the solution is approximated by a Fourier series and for given geometrical values and loading the numerical results are obtained and graphically represented.It must be said that throughout the calculation the free software only was used and for the numerical operations an old laptop is sufficient. The author regards both the former and the latter as a great advantage of the demonstrated method.

  9. Thin walled Nb tubes for suspending test masses in interferometric gravitational wave detectors

    Energy Technology Data Exchange (ETDEWEB)

    Lee, B.H. [School of Physics, University of Western Australia, Crawley 6009, WA (Australia)]. E-mail: bhl@physics.uwa.edu.au; Ju, L. [School of Physics, University of Western Australia, Crawley 6009, WA (Australia); Blair, D.G. [School of Physics, University of Western Australia, Crawley 6009, WA (Australia)

    2006-02-13

    In a previous Letter, we have shown that the use of orthogonal ribbons could provide a better mirror suspension technique in interferometric gravitational wave antennas. One of the key improvements presented by the orthogonal ribbon is the reduction in the number of violin string modes in the direction of the laser. We have considered more elaborate geometries in recent simulations and obtained a suspension that provides further reduction in the number of violin string modes in the direction of the laser, as well as in the direction orthogonal to the laser. This thin walled niobium tube suspension exhibits a reduction in the number of violin modes to 5 in each direction up to a frequency of 5 kHz. Furthermore, the violin mode thermal noise peaks can be reduced in amplitude by 30 dB.

  10. Thin walled Nb tubes for suspending test masses in interferometric gravitational wave detectors

    International Nuclear Information System (INIS)

    Lee, B.H.; Ju, L.; Blair, D.G.

    2006-01-01

    In a previous Letter, we have shown that the use of orthogonal ribbons could provide a better mirror suspension technique in interferometric gravitational wave antennas. One of the key improvements presented by the orthogonal ribbon is the reduction in the number of violin string modes in the direction of the laser. We have considered more elaborate geometries in recent simulations and obtained a suspension that provides further reduction in the number of violin string modes in the direction of the laser, as well as in the direction orthogonal to the laser. This thin walled niobium tube suspension exhibits a reduction in the number of violin modes to 5 in each direction up to a frequency of 5 kHz. Furthermore, the violin mode thermal noise peaks can be reduced in amplitude by 30 dB

  11. Nonlinear free vibration of single walled Carbone NanoTubes conveying fluid

    Directory of Open Access Journals (Sweden)

    Azrar A.

    2014-04-01

    Full Text Available Nonlinear free vibration of single-walled carbon nanotubes (CNTs conveying fluid are modeled and numerically simulated based on von Kármán geometric nonlinearity and Eringen’s nonlocal elasticity theory. The CNTs are modelled as nanobeams where the effects of transverse shear deformation and rotary inertia are considered within the framework of Timoshenko beam theory. The governing equations and boundary conditions are derived using the Hamilton’s principle and the nonlinear equation of motion is solved by the Galerkin’s method. The small scale parameter and the fluid-tube interaction effects on the dynamic behaviours of the CNT-fluid system as well as the instabilities induced by the fluid-velocity can be investigated. The critical fluid-velocity and frequency-amplitude relationships as well as the flutter and divergence instability types and the associated time responses are obtained based on the presented methodological approach.

  12. Hydrogen adsorption in microporous alkali-doped carbons (single-wall carbon nano-tubes and activated carbons)

    International Nuclear Information System (INIS)

    Laurent Duclaux; Szymon Los; Michel Letellier; Philippe Azais; Roland Pellenq; Thomas Roussel; Xavier Fuhr

    2006-01-01

    Doping of microporous carbon by Li or K leads to an increase in the energy of adsorption of H 2 or D 2 molecules. Thus, the room temperature sorption capacities (at P≤3 MPa) can be higher than the ones of the raw materials after slight doping. However, the maximum H 2 (or D 2 ) storage uptake measured at T≤ 77 K is lower than the one of pristine materials as the sites of adsorption are occupied by alkali ions inserted in the micropores. The microporous adsorption sites of doped single-walled carbon nano-tubes, identified by neutron diffraction, are both the interstitial voids (in electric-arc or HiPCO tubes) in between the tubes and the central canals of the tubes (only in HiPCO tubes). (authors)

  13. Evaluation of plugging criteria on steam generator tubes and coalescence model of collinear axial through-wall cracks

    International Nuclear Information System (INIS)

    Lee, Jin Ho; Park, Youn Won; Song, Myung Ho; Kim, Young Jin; Moon, Seong In

    2000-01-01

    In a nuclear power plant, steam generator tubes cover a major portion of the primary pressure-retaining boundary. Thus very conservative approaches have been taken in the light of steam generator tube integrity. According to the present criteria, tubes wall-thinned in excess 40% should be plugged whatever causes are. However, many analytical and experimental results have shown that no safety problems exist even with thickness reductions greater than 40%. The present criterion was developed about twenty years ago when wear and pitting were dominant causes for steam generator tube degradation. And it is based on tubes with single cracks regardless of the fact that the appearance of multiple cracks is more common in general. The objective of this study is to review the conservatism of the present plugging criteria of steam generator tubes and to propose a new coalescence model for two adjacent through-wall cracks existing in steam generator tubes. Using the existing failure models and experimental results, we reviewed the conservatism of the present plugging criteria. In order to verify the usefulness of the proposed new coalescence model, we performed finite element analysis and some parametric studies. Then, we developed a coalescence evaluation diagram

  14. Conservatism of present plugging criteria on steam generator tubes and coalescence model of collinear through-wall axial cracks

    International Nuclear Information System (INIS)

    Lee, Jin Ho; Park, Youn Won; Song, Myung Ho; Kim, Young Jin; Moon, Seong In

    1999-01-01

    The steam generator tubing covers a major portion of the primary pressure-retaining boundary, so that very conservative approaches were taken in the light of steam generator tube integrity. According to the present criteria, tubes wall-thinned in excess of 40% should be plugged whatever the cause was. However, it is reported that there is no safety problem even with thickness reductions greater than 40%. Recently, the plant specific plugging criteria are introduced in many countries by demonstrating that the cracked tube has a sufficient safety margin. One of the drawbacks of such criteria, even though not yet codified, is that it is developed based on tubes with single cracks regardless of the fact that the appearance of multiple cracks is general. Their failure analyses have been, therefore, carried out using an idealized single crack to reduce complexity till now. The objective of this paper is to review the conservatism of the present plugging criteria of steam generator tubes and to propose a new coalescence criterion for twin through-wall cracks existing in steam generator tubes. Using the existing failure models and experimental results, we review the conservatism of the present plugging criteria. In order to verify the usefulness of the proposed new coalescence criterion, we perform finite element analysis

  15. A tale of two neglected systems - structure and function of the thin- and thick-walled sieve tubes in monocotyledonous leaves.

    Directory of Open Access Journals (Sweden)

    Ted eBotha

    2013-08-01

    Full Text Available There is a large body of information relating to the ontogeny, development and the vasculature of eudicotyledonous leaves. However there is less information available concerning the vascular anatomy of monocotyledonous leaves. This is surprising, given that there are two uniquely different phloem systems present in large groups such as grasses and sedges. Monocotyledonous leaves contain marginal, large, intermediate and small longitudinal veins that are interconnected by numerous transverse veins. The longitudinal veins contain two metaphloem sieve tube types, which, based upon their ontogeny and position within the phloem, are termed early (thin-walled and late (thick-walled sieve tubes. Early metaphloem comprises sieve tubes, companion cells and vascular parenchyma cells, whilst the late metaphloem, contains thick-walled sieve tubes that lack companion cells. Thick-walled sieve tubes are generally adjacent to, or no more than one cell removed from the metaxylem. Unlike thin-walled sieve tube-companion cell complexes, thick-walled sieve tubes are connected to parenchyma by pore-plasmodesma units and are generally symplasmically isolated from the thin walled sieve tubes. This paper addresses key structural and functional differences between thin- and thick-walled sieve tubes and explores the unique advantages of alternate transport strategies that this 5 to 7 million year old dual system may offer. It would seem that these two systems may enhance, add to, or play a significant role in increasing the efficiency of solute retrieval as well as of assimilate transfer.

  16. Life Cycle Assessment of Wall Systems

    Science.gov (United States)

    Ramachandran, Sriranjani

    Natural resource depletion and environmental degradation are the stark realities of the times we live in. As awareness about these issues increases globally, industries and businesses are becoming interested in understanding and minimizing the ecological footprints of their activities. Evaluating the environmental impacts of products and processes has become a key issue, and the first step towards addressing and eventually curbing climate change. Additionally, companies are finding it beneficial and are interested in going beyond compliance using pollution prevention strategies and environmental management systems to improve their environmental performance. Life-cycle Assessment (LCA) is an evaluative method to assess the environmental impacts associated with a products' life-cycle from cradle-to-grave (i.e. from raw material extraction through to material processing, manufacturing, distribution, use, repair and maintenance, and finally, disposal or recycling). This study focuses on evaluating building envelopes on the basis of their life-cycle analysis. In order to facilitate this analysis, a small-scale office building, the University Services Building (USB), with a built-up area of 148,101 ft2 situated on ASU campus in Tempe, Arizona was studied. The building's exterior envelope is the highlight of this study. The current exterior envelope is made of tilt-up concrete construction, a type of construction in which the concrete elements are constructed horizontally and tilted up, after they are cured, using cranes and are braced until other structural elements are secured. This building envelope is compared to five other building envelope systems (i.e. concrete block, insulated concrete form, cast-in-place concrete, steel studs and curtain wall constructions) evaluating them on the basis of least environmental impact. The research methodology involved developing energy models, simulating them and generating changes in energy consumption due to the above mentioned

  17. Study of tensile test behavior of austenitic stainless steel type 347 seamless thin-walled tubes in cold worked condition

    Energy Technology Data Exchange (ETDEWEB)

    Terui, Clarice, E-mail: clarice.terui@marinha.mil.br [Centro Tecnológico da Marinha em São Paulo (CINA/CTMSP), Iperó, SP (Brazil). Centro Industrial Nuclear da Marinha; Lima, Nelson B. de, E-mail: nblima@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNE-SP), Sao Paulo, SP (Brazil)

    2017-07-01

    These austenitic stainless steel type 347 seamless thin-walled tubes are potential candidates to be used in fuel elements of nuclear power plants (as PWR - Pressurized Water Reactor). So, their metallurgical condition and mechanical properties, as the tensile strength and yield strength, normally are very restrict in demanding project and design requirements. Several full size tensile tests at room temperature and high temperature (315 deg C) were performed in these seamless tubes in cold-worked condition. The results of specified tensile and yield strengths were achieved but the elongation of the tube, in the geometry of the component, could not be measured at high temperature due to unconventional mode of rupture (helical mode without separation of parts). The average value of elongation was obtained from stress-strain curves of hot tensile tests and was around 5%. The results obtained in this research show that this behavior of the full size tensile test samples of thin-walled tube (wall thickness less than 0.5 mm) in high temperature (315°C) is due to the combination of the manufacturing process, the material (crystallographic structure and chemical composition) and the final geometry of the component. In other words, the strong crystallographic texture of material induced by tube drawing process in addition with the geometry of the component are responsible for the behavior in hot uniaxial tensile tests. (author)

  18. Two simple methods for calculating the penetration time of a longitudinal magnetic field through the wall of a metallic tube

    International Nuclear Information System (INIS)

    Jimenez D, H.; Colunga S, S.; Lopez C, R.; Melendez L, L.; Ramos S, J.; Cabral P, A.; Gonzalez T, L.; Chavez A, E.; Valencia A, R.

    1991-06-01

    Two simple and fast methods to calculate the penetration time of a longitudinal magnetic field through the wall of a long metallic tube of circular cross section are presented. The first method is based upon the proposition of an 'effective penetration thickness' given by the polar angle average of all possible straight-line transverse penetration paths of field lines through the tube wall. This method provides a quick calculation that yields a remarkably good approximation to experimental and reported values of the penetration time. In the second method the tube is considered as a RL circuit. Thus the penetration time is given by the ratio L T /R T where L T is the inductance of the tube considered as a one turn coil, and R T is the tube resistance. This method is faster to apply than the previous one but the values obtained provide only a rough approximation to the penetration time. Applications of the two methods are given for the tokamak chambers of the Japanese 'HYBTOK', the Brazilian 'TBR' and the Mexican 'Novillo'. The resulting values of the penetration time approximate very well to the reported ones in the first two cases and to the experimental one in the last. The methods are also applied to calculate the penetration time in two long tubes, one of aluminum and other of copper. Calculated values approximate very well to measured values. (Author)

  19. Complete Status Report Documenting Weld Development for Thin Wall Tubing of ODS Ferritic Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hoelzer, David T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Edmondson, Philip D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Tang, Wei [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Feng, Zhili [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-16

    Beginning in 2015, research in the FCRD program began the development of FSW for joining thin sections of 14YWT in the form of thin (0.5 mm) plate and ultimately thin wall tubing. In the previous fiscal year, a ~1 mm thick plate, or sheet, of 14YWT was produced by hot rolling with no edge cracking. The initial FSW experiment was performed on the 1 mm thick plate and involved a bead-on-plate weld in which the spinning pin tool is plunged into the plate surface, but does not penetrate the thickness of the plate, and then travels the length of the plate. The FSW run successfully produced a bead-on-plate stir zone on the 1 mm thick plate of 14YWT, but no characterization studies of the stir zone were performed by the end of FY15. Therefore, the results presented in this report cover the microstructural analysis of the bead-on-plate stir zone and the initial research task on obtaining tensile properties of the stir zone using the digital image correlation (DIC) approach during testing of miniature tensile specimens to assess the quality of the FSW parameters used in the initial experiment. The results of the microstructural characterization study using optical, scanning electron and scanning transmission electron microscopies showed the grain structure in the SZ to have isotropic and irregular shape but very similar size compared to the highly elongated grains oriented horizontally with the plane of the plate that were observed in the unaffected zone of 14YWT. Several cracks oriented horizontally were observed mostly on the retreating side of the SZ in both the SZ and TMAZ. These cracks may have formed due to insufficient pressure being exerted on the top surface of the plate by the shoulder and pin tool during the FSW run. High resolution STEM-EDS analysis showed the presence of the Y-Ti-O particles in the SZ, but that some particles exhibited coarsening. Overall, the FSW parameters used to produce the bead-on-plate SZ in the 0.1 cm thick plate of 14YWT were nearly

  20. Structural integrity assessment of steam generator tubes deteriorated through primary water stress corrosion cracking in transition region of tube expansion

    International Nuclear Information System (INIS)

    Silveira, Helvecio Carlos Klinke da

    2002-01-01

    In PWR plants, steam generator tube degradation has been one of the most important economical concerns, besides causing operational safety problems. In this work, a survey of steam generator tube degradation modes is done. Degradation mechanisms and influence factors are introduced and discussed. The importance of stress corrosion cracking, especially in transition region of tube expansion zone, is underlined. The actual steam generator tube plugging criteria are conservative. Proposed alternative criteria are introduced and discussed. Distinction is done to structural integrity assessment of defective tubes. Real data of tube defect indications of axial cracks in expansion transition zone due to primary water stress corrosion cracking are used in analysis. Results allow discussing application aspects of deterministic and probabilistic criteria on structural integrity assessment of tubes with defect indications. Applied models are specifics, but the application of concept may be extended to other steam generator tube degradation modes. (author)

  1. Radiant and convective heat transfer for flow of a transparent gas in a short tube with prescribed sinusoidal wall heat flux

    International Nuclear Information System (INIS)

    de Lemos, M.J.S.

    1982-01-01

    The present analysis accounts for radiant and convective heat transfer for a transparent fluid flowing in a short tube with prescribed wall heat flux. The heat flux distribution used was of sine shape with maximum at the middle of the tube. Such a solution is the approximate one for axial power in a nuclear reactor. The solutions for the tube wall and gas bulk temperatures were obtained by successive substitutions for the wall and gas balance energy equations. The results show a decrease of 30% for the maximum wall temperature using black surface (e = 1). In this same case, the increasing in the gas temperature shows a decrease of 58%

  2. Status of Joining Thin Sheet and Thin Wall Tubes of 14YWT

    Energy Technology Data Exchange (ETDEWEB)

    Hoelzer, David T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Unocic, Kinga A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Tang, Wei [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Feng, Zhili [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-09-18

    Beginning this fiscal year, the FCRD research project initiated an investigation on joining thin sections of the advanced ODS 14YWT ferritic alloy. Friction stir welding (FSW) was investigated as a method to join thin plate and tubing of 14YWT since it is a solid state joining method that has been shown in past studies to be a promising method for joining plates of ODS alloys, such as 14YWT. However, this study will attempt to be the first to demonstrate if FSW can successfully join thin plates and thin wall tubing of 14YWT. In the first FSW attempt, a 1.06 cm thick plate of 14YWT (SM13 heat) was successfully rolled at 1000ºC to the target thickness of 0.1 cm with no edge cracking. This achievement is a highlight since previous attempts to roll 14YWT plates have resulted in extensive cracking. For the FSW run, a pin tool being developed by the ORNL FSW Process Development effort was used. The first FSW run successfully produced a bead-on-plate weld in the 0.1 cm thick plate. The quality of the weld zone appears very good with no evidence of large defects such as cavities. The microstructural characterization study of the bead-on-plate weld zone has been initiated to compare the results of the microstructure analysis with those obtained in the reference microstructural analysis of the 14YWT (SM13 heat) that showed ultra-fine grain size of 0.43 μm and a high number density of ~2-5 nm sizes oxygen-enriched nanoclusters.

  3. The apical actin fringe contributes to localized cell wall deposition and polarized growth in the lily pollen tube.

    Science.gov (United States)

    Rounds, Caleb M; Hepler, Peter K; Winship, Lawrence J

    2014-09-01

    In lily (Lilium formosanum) pollen tubes, pectin, a major component of the cell wall, is delivered through regulated exocytosis. The targeted transport and secretion of the pectin-containing vesicles may be controlled by the cortical actin fringe at the pollen tube apex. Here, we address the role of the actin fringe using three different inhibitors of growth: brefeldin A, latrunculin B, and potassium cyanide. Brefeldin A blocks membrane trafficking and inhibits exocytosis in pollen tubes; it also leads to the degradation of the actin fringe and the formation of an aggregate of filamentous actin at the base of the clear zone. Latrunculin B, which depolymerizes filamentous actin, markedly slows growth but allows focused pectin deposition to continue. Of note, the locus of deposition shifts frequently and correlates with changes in the direction of growth. Finally, potassium cyanide, an electron transport chain inhibitor, briefly stops growth while causing the actin fringe to completely disappear. Pectin deposition continues but lacks focus, instead being delivered in a wide arc across the pollen tube tip. These data support a model in which the actin fringe contributes to the focused secretion of pectin to the apical cell wall and, thus, to the polarized growth of the pollen tube. © 2014 American Society of Plant Biologists. All Rights Reserved.

  4. Copper hexacyanoferrate functionalized single-walled carbon nano-tubes for selective cesium extraction

    International Nuclear Information System (INIS)

    Draouil, H.; Alvarez, L.; Bantignies, J.L.; Causse, J.; Cambedouzou, J.; Flaud, V.; Zaibi, M.A.; Oueslati, M.

    2017-01-01

    Single-walled carbon nano-tubes (SWCNTs) are functionalized with copper hexacyanoferrate (CuHCF) nanoparticles to prepare solid substrates for sorption of cesium ions (Cs + ) from liquid outflows. The high mechanical resistance and large electrical conductivity of SWCNTs are associated with the ability of CuHCF nanoparticles to selectively complex Cs + ions in order to achieve membrane-like buckypapers presenting high loading capacity of cesium. The materials are thoroughly characterized using electron microscopy, Raman scattering, X-ray photoelectron spectroscopy and thermogravimetric analyses. Cs sorption isotherms are plotted after having measured the Cs + concentration by liquid phase ionic chromatography in the solution before and after exposure to the materials. It is found that the total sorption capacity of the material reaches 230 mg.g -1 , and that about one third of the sorbed Cs (80 mg.g -1 ) is selectively complexed in the CuHCF nanoparticles grafted on SWCNTs. The quantification of Cs + ions on different sorption sites is made for the first time, and the high sorption rates open interesting outlooks in the integration of such materials in devices for the controlled sorption and desorption of these ions. (authors)

  5. Bioactive surface modifications on inner walls of poly-tetra-fluoro-ethylene tubes using dielectric barrier discharge

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yong Ki [Department of Physics, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Heat Treatment and Surface Engineering R and D Group, Korea Institute of Industrial Technology, Incheon 406-840 (Korea, Republic of); Park, Daewon; Kim, Hoonbae [Department of Physics, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Lee, Hyerim; Park, Heonyong [Department of Molecular Biology, Dankook University, Yongin 448-701 (Korea, Republic of); Kim, Hong Ja [Department of Internal Medicine, Dankook University, Cheonan 330-714 (Korea, Republic of); Jung, Donggeun, E-mail: djung@skku.ac.kr [Department of Physics, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2014-03-01

    Graphical abstract: - Highlights: • The surface modification of the inner walls of poly-tetra-fluoro-ethylene (PTFE) tubing was carried out to improve vascular grafts. • Focus was centered on the cell attachment of the inner wall of the PTFE by sequential processes of hydrogen plasma treatment, hydrocarbon deposition, and reactive plasma treatment using micro plasma discharge. - Abstract: Bioactive surface modification can be used in a variety of medical polymeric materials in the fields of biochips and biosensors, artificial membranes, and vascular grafts. In this study, the surface modification of the inner walls of poly-tetra-fluoro-ethylene (PTFE) tubing was carried out to improve vascular grafts, which are made of biocompatible material for the human body in the medical field. Focus was centered on the cell attachment of the inner wall of the PTFE by sequential processes of hydrogen plasma treatment, hydrocarbon deposition, and reactive plasma treatment on the PFTE surface using micro plasma discharge. Micro plasma was generated by a medium-frequency alternating current high-voltage generator. The preliminary modification of PTFE was conducted by a plasma of hydrogen and argon gases. The hydrocarbon thin film was deposited on modified PTFE with a mixture of acetylene and argon gases. The reactive plasma treatment using oxygen plasma was done to give biocompatible functionality to the inner wall surface. The hydrophobic surface of bare PTFE is made hydrophilic by the reactive plasma treatment due to the formation of carbonyl groups on the surface. The reactive treatment could lead to improved attachment of smooth muscle cells (SMCs) on the modified PTFE tubing. Fourier transform infrared absorption spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and water contact angle measurement were used for the analysis of the surface modification. The SMC-attached PTFE tube developed will be applicable to in vitro human vasculature

  6. Bioactive surface modifications on inner walls of poly-tetra-fluoro-ethylene tubes using dielectric barrier discharge

    International Nuclear Information System (INIS)

    Cho, Yong Ki; Park, Daewon; Kim, Hoonbae; Lee, Hyerim; Park, Heonyong; Kim, Hong Ja; Jung, Donggeun

    2014-01-01

    Graphical abstract: - Highlights: • The surface modification of the inner walls of poly-tetra-fluoro-ethylene (PTFE) tubing was carried out to improve vascular grafts. • Focus was centered on the cell attachment of the inner wall of the PTFE by sequential processes of hydrogen plasma treatment, hydrocarbon deposition, and reactive plasma treatment using micro plasma discharge. - Abstract: Bioactive surface modification can be used in a variety of medical polymeric materials in the fields of biochips and biosensors, artificial membranes, and vascular grafts. In this study, the surface modification of the inner walls of poly-tetra-fluoro-ethylene (PTFE) tubing was carried out to improve vascular grafts, which are made of biocompatible material for the human body in the medical field. Focus was centered on the cell attachment of the inner wall of the PTFE by sequential processes of hydrogen plasma treatment, hydrocarbon deposition, and reactive plasma treatment on the PFTE surface using micro plasma discharge. Micro plasma was generated by a medium-frequency alternating current high-voltage generator. The preliminary modification of PTFE was conducted by a plasma of hydrogen and argon gases. The hydrocarbon thin film was deposited on modified PTFE with a mixture of acetylene and argon gases. The reactive plasma treatment using oxygen plasma was done to give biocompatible functionality to the inner wall surface. The hydrophobic surface of bare PTFE is made hydrophilic by the reactive plasma treatment due to the formation of carbonyl groups on the surface. The reactive treatment could lead to improved attachment of smooth muscle cells (SMCs) on the modified PTFE tubing. Fourier transform infrared absorption spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and water contact angle measurement were used for the analysis of the surface modification. The SMC-attached PTFE tube developed will be applicable to in vitro human vasculature

  7. State-variable analysis of inelastic deformation of thin-walled tubes. II. Data analysis and simulations

    International Nuclear Information System (INIS)

    Wire, G.L.; Duncan, D.R.; Cannon, N.S.; Johnson, G.D.; Alexopoulos, P.S.; Li, C.Y.

    Inelastic analysis is performed to calculate the deformation of thin-walled, internally pressurized, tube under a variety of loading modes. A state-variable approach was used to describe the material properties. The material parameters of the constitutive equations used were determined based on uniaxial, load relaxation, tensile tests, and internally pressurized tubes under creep and constant-displacement-rate modes of loading. The simulated results were compared with the experimental data. The significance of the comparison is discussed in terms of the validity of a state-variable approach used to describe the deformation properties in mechanical testing

  8. Effect of two dimensional heat conduction within the wall on heat transfer of a tube partially heated on its circumference

    International Nuclear Information System (INIS)

    Satoh, Isao; Kurosaki, Yasuo

    1987-01-01

    This paper dealt with the numerical calculations of the heat transfer of a tube partially heated on its circumference, considering two-dimensional heat conduction within the wall. The contribution of the unheated region of the tube wall to heat tranfer of the heated region was explained by the term of 'fin efficiency of psuedo-fin', it was clarified that the fin efficiency of the unheated region was little affected by the temperature difference between the inner and outer surfaces of the wall, and could be approximated by the fin efficency of a rectangular fin. Both the circumferential and radial heat conductions within the wall affected the temperature difference between the inner and outer surfaces of the heated region; however, the effect of the temperature difference on the circumferentially average Nusselt number could be obtained by using the analytical solution of radially one-dimensional heat conduction. Using these results, a diagram showing the effect of wall conduction on heat transfer, which is useful for designing the circumferentially nonuniformly heated coolant passages, was obtained. (author)

  9. Mathematical Model for Thin-walled Corrugated Tube under Axial Compression

    Directory of Open Access Journals (Sweden)

    Eyvazian Arameh

    2016-01-01

    Full Text Available In this research, theoretical investigation of corrugated aluminum tubes is performed to predicting the energy absorption characteristics. Aim to deform plastic tubes in predetermined intervals, corrugations are introduced on its surface. Theoretical relations are presented for predicting the energy absorption and mean crushing load of corrugated tubes. Other than that, corrugation helps to control the failure mode.

  10. Analysis of a multi pass weld of a thick walled tube made of austenitic stainless steel X6 CrNiNb 18 10

    International Nuclear Information System (INIS)

    Scholtes, B.; Zinn, W.; Ilg, U.; Backfisch, W.; Gibmeier, J.; Kirch, D.

    2006-01-01

    In this paper, microstructure and residual stresses of a multi pass welding of a thick-walled tube made of austenitic stainless steel X6 CrNiNb 18 10 (1.4550) are systematically characterized and assessed. Results of microstructural and phase analyses, residual stress and hardness measurements as well as of a tensile test using micro specimen and SEM analyses are presented. Using these data, plastic deformations occurring during the welding process in the vicinity of the weld seam are evaluated. Finally, consequences of an additional heat treatment at 400 C/24 h are studied. (Abstract Copyright [2006], Wiley Periodicals, Inc.) [de

  11. Flow and axial dispersion in a sinusoidal-walled tube: Effects of inertial and unsteady flows

    Science.gov (United States)

    Richmond, Marshall C.; Perkins, William A.; Scheibe, Timothy D.; Lambert, Adam; Wood, Brian D.

    2013-12-01

    In this work, we consider a sinusoidal-walled tube (a three-dimensional tube with sinusoidally-varying diameter) as a simplified conceptualization of flow in porous media. Direct numerical simulation using computational fluid dynamics (CFD) methods was used to compute velocity fields by solving the Navier-Stokes equations, and also to numerically solve the volume averaging closure problem, for a range of Reynolds numbers (Re) spanning the low-Re to inertial flow regimes, including one simulation at Re=449 for which unsteady flow was observed. The longitudinal dispersion observed for the flow was computed using a random walk particle tracking method, and this was compared to the longitudinal dispersion predicted from a volume-averaged macroscopic mass balance using the method of volume averaging; the results of the two methods were consistent. Our results are compared to experimental measurements of dispersion in porous media and to previous theoretical results for both the low-Re, Stokes flow regime and for values of Re representing the steady inertial regime. In the steady inertial regime, a power-law increase in the effective longitudinal dispersion (DL) with Re was found, and this is consistent with previous results. This rapid rate of increase is caused by trapping of solute in expansions due to flow separation (eddies). One unsteady (but non-turbulent) flow case (Re=449) was also examined. For this case, the rate of increase of DL with Re was smaller than that observed at lower Re. Velocity fluctuations in this regime lead to increased rates of solute mass transfer between the core flow and separated flow regions, thus diminishing the amount of tailing caused by solute trapping in eddies and thereby reducing longitudinal dispersion. The observed tailing was further explored through analysis of concentration skewness (third moment) and its assymptotic convergence to conventional advection-dispersion behavior (skewness = 0). The method of volume averaging was

  12. Assessment of beam tube performance for the maple research reactor

    International Nuclear Information System (INIS)

    Lee, A.G.

    1986-06-01

    The MAPLE research reactor is a versatile new research facility that can be adapted to meet the requirements of a variety of reactor applications. A particular group of reactor applications involves the use of beams of radiation extracted from the reactor core via tubes that penetrate through the biological shield and terminate in the reflector surrounding the fuelled core. An assessment is given of the neutron and gamma radiation fields entering beam tubes that are located radially or tangentially with respect to the core

  13. Assessing corrosion of MSE wall reinforcement.

    Science.gov (United States)

    2010-09-01

    The primary objective of this study was to extract reinforcement coupons from select MSE walls and document the extent of corrosion. In doing this, a baseline has been established against which coupons extracted in the future can be compared. A secon...

  14. A Eutectic Melting Study of Double Wall Cladding Tubes of FeCrAl and Zircaloy-4

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Woojin; Son, Seongmin; Lee, You Ho; Lee, Jeong Ik; Ryu, Ho Jin [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Jeong, Eun [Kyunghee University, Yongin (Korea, Republic of)

    2015-10-15

    The eutectic melting behavior of FeCrAl/Zircaloy-4 double wall cladding tubes was investigated by annealing at various temperatures ranging from 900 .deg. C to 1300 .deg. C. It was found that significant eutectic melting occurred after annealing at temperatures equal to or higher than 1150 .deg. C. It means that an additional diffusion barrier layer is necessary to limit the eutectic melting between FeCrAl and Zircaloy-4 alloy cladding tubes. Coating of FeCrAl layers on the Zr alloy cladding tube is being investigated for the development of accident tolerant fuel by exploiting of both the oxidation resistance of FeCrAl alloys and the neutronic advantages of Zr alloys. Coating of FeCrAl alloys on Zr alloy cladding tubes can be performed by various techniques including thermal spray, laser cladding, and co-extrusion. Son et al. also reported the fabrication of FeCrAl/Zr ally double wall cladding by the shrink fit method. For the double layered cladding tubes, the thermal expansion mismatch between the dissimilar materials, severe deformation or mechanical failure due to the evolution of thermal stresses can occur when there is a thermal cycling. In addition to the thermal stress problems, chemical compatibilities between the two different alloys should be investigated in order to check the stability and thermal margin of the double wall cladding at a high temperature. Generally, it is considered that Zr alloy cladding will maintain its mechanical integrity up to 1204 .deg. C (2200 .deg. F) to satisfy the acceptance criteria for emergency core cooling systems.

  15. Assessment for hydrodynamic masses of HANARO flow tubes

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Jeong Soo; Cho, Yeong Garp; Kim, Doo Kie; Woo, Jong Sug; Park, Jin Ho

    2000-06-01

    The effect of hydrodynamic masses is investigated in dynamic characteristics and seismic response analyses of the submerged HANARO hexagonal flow tubes. Consistent hydrodynamic masses of the surrounding water are evaluated by the prepared program using the finite element method, in which arbitrary cross-sections of submerged structures and boundary conditions of the surrounding fluid can be considered. Also lumped hydrodynamic masses are calculated using simple formula applied to hexagonal flow tubes in the infinite fluid. Modal analyses and seismic response spectrum analyses were performed using hydrodynamic masses obtained by the finite element method and the simple formula. The results of modal analysis were verified by comparing the results measured from modal tests. And the displacement results of the seismic response spectrum analysis were assessed by comparing the consistent and the lumped hydrodynamic masses obtained by various methods. Finally practical criteria based on parametric studies are proposed as the lumped hydrodynamic masses for HANARO flow tubes.

  16. Assessment for hydrodynamic masses of HANARO flow tubes

    International Nuclear Information System (INIS)

    Ryu, Jeong Soo; Cho, Yeong Garp; Kim, Doo Kie; Woo, Jong Sug; Park, Jin Ho

    2000-06-01

    The effect of hydrodynamic masses is investigated in dynamic characteristics and seismic response analyses of the submerged HANARO hexagonal flow tubes. Consistent hydrodynamic masses of the surrounding water are evaluated by the prepared program using the finite element method, in which arbitrary cross-sections of submerged structures and boundary conditions of the surrounding fluid can be considered. Also lumped hydrodynamic masses are calculated using simple formula applied to hexagonal flow tubes in the infinite fluid. Modal analyses and seismic response spectrum analyses were performed using hydrodynamic masses obtained by the finite element method and the simple formula. The results of modal analysis were verified by comparing the results measured from modal tests. And the displacement results of the seismic response spectrum analysis were assessed by comparing the consistent and the lumped hydrodynamic masses obtained by various methods. Finally practical criteria based on parametric studies are proposed as the lumped hydrodynamic masses for HANARO flow tubes

  17. A standardized procedure for eddy-current testing of stainless steel, thin-walled nuclear fuel element cladding tubes

    International Nuclear Information System (INIS)

    Barat, P.; Raj, B.; Bhattacharya, D.K.

    1982-01-01

    Thin-walled nuclear fuel cladding tubes made of AISI 316 stainless steel have been examined by eddy-current testing. Standardization of the procedures has required investigations on optimizing the test frequency, finding a method to locate a defect with respect to the probe reference end, and the use of standard defects and sequential metallography of natural defects detected by eddy-current testing, to understand the influence of the nature of defects on the impedance output signals. Test frequency and method of locating the defect were optimized by the use of standard defects made by machining in reference cladding tubes. Subsequent metallography of natural defects detected by eddy-current testing revealed mainly clusters of inclusions but also other types of defects. The effect of the distribution of inclusions along the length of the tube on the impedance output is discussed. (author)

  18. Standardized procedure for eddy-current testing of stainless steel, thin-walled nuclear fuel element cladding tubes

    Energy Technology Data Exchange (ETDEWEB)

    Barat, P; Raj, B; Bhattacharya, D K [Reactor Research Centre, Kalpakkam (India)

    1982-10-01

    Thin-walled nuclear fuel cladding tubes made of AISI 316 stainless steel have been examined by eddy-current testing. Standardization of the procedures has required investigations on optimizing the test frequency, finding a method to locate a defect with respect to the probe reference end, and the use of standard defects and sequential metallography of natural defects detected by eddy-current testing, to understand the influence of the nature of defects on the impedance output signals. Test frequency and method of locating the defect were optimized by the use of standard defects made by machining in reference cladding tubes. Subsequent metallography of natural defects detected by eddy-current testing revealed mainly clusters of inclusions but also other types of defects. The effect of the distribution of inclusions along the length of the tube on the impedance output is discussed.

  19. Developmental evolution of flowering plant pollen tube cell walls: callose synthase (CalS gene expression patterns

    Directory of Open Access Journals (Sweden)

    Abercrombie Jason M

    2011-07-01

    Full Text Available Abstract Background A number of innovations underlie the origin of rapid reproductive cycles in angiosperms. A critical early step involved the modification of an ancestrally short and slow-growing pollen tube for faster and longer distance transport of sperm to egg. Associated with this shift are the predominantly callose (1,3-β-glucan walls and septae (callose plugs of angiosperm pollen tubes. Callose synthesis is mediated by callose synthase (CalS. Of 12 CalS gene family members in Arabidopsis, only one (CalS5 has been directly linked to pollen tube callose. CalS5 orthologues are present in several monocot and eudicot genomes, but little is known about the evolutionary origin of CalS5 or what its ancestral function may have been. Results We investigated expression of CalS in pollen and pollen tubes of selected non-flowering seed plants (gymnosperms and angiosperms within lineages that diverged below the monocot/eudicot node. First, we determined the nearly full length coding sequence of a CalS5 orthologue from Cabomba caroliniana (CcCalS5 (Nymphaeales. Semi-quantitative RT-PCR demonstrated low CcCalS5 expression within several vegetative tissues, but strong expression in mature pollen. CalS transcripts were detected in pollen tubes of several species within Nymphaeales and Austrobaileyales, and comparative analyses with a phylogenetically diverse group of sequenced genomes indicated homology to CalS5. We also report in silico evidence of a putative CalS5 orthologue from Amborella. Among gymnosperms, CalS5 transcripts were recovered from germinating pollen of Gnetum and Ginkgo, but a novel CalS paralog was instead amplified from germinating pollen of Pinus taeda. Conclusion The finding that CalS5 is the predominant callose synthase in pollen tubes of both early-diverging and model system angiosperms is an indicator of the homology of their novel callosic pollen tube walls and callose plugs. The data suggest that CalS5 had transient expression

  20. Removal of Malachite Green Dye from Aqueous Solution Using Multi-Walled Carbon Nano tubes: An Application of Experimental Design

    International Nuclear Information System (INIS)

    Siti Aminah Zulkepli; Md Pauzi Abdullah; Md Pauzi Abdullah; Wan Mohd Afiq Wan Mohd Khalik

    2016-01-01

    An experimental design methodology was performed in the optimization of removal of malachite green dye by multi-walled carbon nano tubes. A Central Composite Design (25) was chosen to develop a mathematical model and determine the optimum condition for adsorption of malachite green by carbon nano tubes. Five experimental factors, namely initial dye concentration, mass of adsorbent, pH, contact time and agitation speed were studied. Maximum adsorption of malachite green was achieved at the suggested optimum conditions: initial dye concentration (20 ppm), weight of adsorbent (0.03 g), pH solution (7) contact time (17 min) and agitation speed (150 strokes per min). The experimental value of adsorption by multi-walled carbon nano tubes were found to be in good agreement with the predicted value (R"2 = 0.922).The experimental equilibrium data were best fitted to isotherm model (Langmuir) and kinetic model (pseudo second-order) respectively. Maximum adsorption by carbon nano tubes at monolayer for malachite green was obtained at 112.36 mg/ g while kinetic rate constant was calculated to be 0.0017 g mg"-"1 min"-"1. (author)

  1. Perspectives of Single-Wall Carbon Nano-tube Production in the Arc Discharge Process

    International Nuclear Information System (INIS)

    Krestinin, A.V.; Kiselev, N.A.; Raevskii, A.V; Ryabenko, A.G.; Zakharov, D.N.; Zvereva, G.I.

    2003-01-01

    Single-wall carbon nano tubes (SWNTs) promise wide applications in many technical fields. As a result purified SWNT material is sold now on the West market at more than 1000 dollars per 1 gram. Thus developing an effective technology for SWNTs production rises to a very important sintofene problem. The perspectives of three existing methods providing raw material in the technology of SWNT production have been analyzed. They are i) pulsed laser evaporation of graphite/metal composites, ii) evaporation of graphite electrodes with metal content in the are discharge process, and iii) catalytic decomposition of the mixture of CO and metal carbonyl catalyst precursor. The observed dynamites of SWNT market points to replacing the laser method of SWNTs production by the are process. The conclusion has been made that the technology based on the are process will be the major one for the fabrication of purified SWNTs at least for the next five years. A reliable estimation of a low price limit of SWNTs was derived from a comparison of two technologies based on the are discharge process: the first one is the production of SWNTs and the second one is the production of a fullerene mixture C 6 0 + C 7 0. The main conclusion was made that the price of purified SWNTs should always be more by 2-3 times the price of fullerene mixture. The parameters of a lab-scale technology for the production of purified SWNTs are listed. A large-scale application of the developed technology is expected to reduce the price of purified SWNTs by approximately ten times. The methods now employed for the characterization of products containing SWNTs are briefly observed. It is concluded that electron microscopy, thermogravimetric analysis, absorption and Raman spectroscopy, measurement of the specific surface aria, optical microscopy - each in separation is not enough for extensive characterization of a sample containing SWNTs, and all these methods should be used together. (author)

  2. Uptake of gaseous formaldehyde onto soil surfaces: a coated-wall flow tube study

    Science.gov (United States)

    Li, Guo; Su, Hang; Li, Xin; Meusel, Hannah; Kuhn, Uwe; Pöschl, Ulrich; Shao, Min; Cheng, Yafang

    2015-04-01

    Gaseous formaldehyde (HCHO) is an important intermediate molecule and source of HO2 radicals. However, discrepancies exist between model simulated and observed HCHO concentrations, suggesting missing sources or sinks in the HCHO budget. Multiphase processes on the surface of soil and airborne soil-derived particles have been suggested as an important mechanism for the production/removal of atmospheric trace gases and aerosols. In this work, the uptake of gaseous HCHO on soil surfaces were investigated through coated-wall flow tube experiments with HCHO concentration ranging from 10 to 40 ppbv. The results show that the adsorption of HCHO occurred on soil surfaces, and the uptake coefficient dropped gradually (i.e., by a factor of 5 after 1 hour) as the reactive surface sites were consumed. The HCHO uptake coefficient was found to be affected by the relative humidity (RH), decreasing from (2.4 ± 0.5) × 10-4 at 0% RH to (3.0 ± 0.08) × 10-5 at 70% RH, due to competition of water molecule absorption on the soil surface. A release of HCHO from reacted soil was also detected by applying zero air, suggesting the nature of reversible physical absorption and the existence of an equilibrium at the soil-gas interface. It implies that soil could be either a source or a sink for HCHO, depending on the ambient HCHO concentration. We also develop a Matlab program to calculate the uptake coefficient under laminar flow conditions based on the Cooney-Kim-Davis method.

  3. Convective heat transport of high-pressure flows inside active, thick walled-tubes with isothermal outer surfaces: usage of Nusselt correlation equations for an inactive, thin walled-tube

    Energy Technology Data Exchange (ETDEWEB)

    Campo, Antonio [Idaho State Univ., Nuclear Engineering Dept., Pocatello, ID (United States); Sanchez, Alejo [Universidad de los Andes, Depto. de Ingenieria Mecanica, Merida (Venezuela)

    1998-03-01

    A semi-analytical analysis was conducted for the prediction of the mean bulk- and interface temperatures of gaseous and liquid fluids moving laminarly at high pressures inside thick-walled metallic tubes. The outer surfaces of the tubes are isothermal. The central goal of this article is to critically examine the thermal response of this kind of in-tube flows utilizing two versions of the 1-D lumped model: one is differential-numerical while the other is differential-algebraic. For the former, the local Nusselt number characterizing an inactive, isothermal tube was taken from correlation equations reported in the heat transfer literature. For the latter, a streamwise-mean Nusselt number associated with an active, isothermal tube was taken from standard correlation equations that appear in text-books on basic heat transfer. For the two different versions of the 1-D lumped model tested, the computed results consistently demonstrate that the differential-algebraic, provides accurate estimates of both the mean bulk- and the interface temperatures when compared with those temperature results computed with formal 2-D differential models. (author)

  4. Evaluation on double-wall-tube residual stress distribution of sodium-heated steam generator by neutron diffraction and numerical analysis

    International Nuclear Information System (INIS)

    Kisohara, N.; Suzuki, H.; Akita, K.; Kasahara, N.

    2012-01-01

    A double-wall-tube is nominated for the steam generator heat transfer tube of future sodium fast reactors (SFRs) in Japan, to decrease the possibility of sodium/water reaction. The double-wall-tube consists of an inner tube and an outer tube, and they are mechanically contacted to keep the heat transfer of the interface between the inner and outer tubes by their residual stress. During long term SG operation, the contact stress at the interface gradually falls down due to stress relaxation. This phenomenon might increase the thermal resistance of the interface and degrade the tube heat transfer performance. The contact stress relaxation can be predicted by numerical analysis, and the analysis requires the data of the initial residual stress distributions in the tubes. However, unclear initial residual stress distributions prevent precious relaxation evaluation. In order to resolve this issue, a neutron diffraction method was employed to reveal the tri-axial (radius, hoop and longitudinal) initial residual stress distributions in the double-wall-tube. Strain gauges also were used to evaluate the contact stress. The measurement results were analyzed using a JAEA's structural computer code to determine the initial residual stress distributions. Based on the stress distributions, the structural computer code has predicted the transition of the relaxation and the decrease of the contact stress. The radial and longitudinal temperature distributions in the tubes were input to the structural analysis model. Since the radial thermal expansion difference between the inner (colder) and outer (hotter) tube reduces the contact stress and the tube inside steam pressure contributes to increasing it, the analytical model also took these effects into consideration. It has been conduced that the inner and outer tubes are contacted with sufficient stresses during the plant life time, and that effective heat transfer degradation dose not occur in the double-wall-tube SG. (authors)

  5. Probabilistic methodology for assessing steam generator tube inspection - Phase II: CANTIA - a probabilistic method for assessing steam generator tube inspections

    International Nuclear Information System (INIS)

    Harris, J.E.; Gorman, J.A.; Turner, A.P.L.

    1997-03-01

    The objectives of this project were to develop a computer-based method for probabilistic assessment of inspection strategies for steam generator tubes, and to document the source code and to provide a user's manual for it. The program CANTIA was created to fulfill this objective, and the documentation and verification of the code is provided in this volume. The user's manual for CANTIA is provided as a separate report. CANTIA uses Monte Carlo techniques to determine approximate probabilities of steam generator tube failures under accident conditions and primary-to-secondary leak rates under normal and accident conditions at future points in time. The program also determines approximate future flaw distributions and non-destructive examination results from the input data. The probabilities of failure and leak rates and the future flaw distributions can be influenced by performing inspections of the steam generator tubes at some future points in time, and removing defective tubes from the population. The effect of different inspection and maintenance strategies can therefore be determined as a direct effect on the probability of tube failure and primary-to-secondary leak rate

  6. 3D cardiac wall thickening assessment for acute myocardial infarction

    Science.gov (United States)

    Khalid, A.; Chan, B. T.; Lim, E.; Liew, Y. M.

    2017-06-01

    Acute myocardial infarction (AMI) is the most severe form of coronary artery disease leading to localized myocardial injury and therefore irregularities in the cardiac wall contractility. Studies have found very limited differences in global indices (such as ejection fraction, myocardial mass and volume) between healthy subjects and AMI patients, and therefore suggested regional assessment. Regional index, specifically cardiac wall thickness (WT) and thickening is closely related to cardiac function and could reveal regional abnormality due to AMI. In this study, we developed a 3D wall thickening assessment method to identify regional wall contractility dysfunction due to localized myocardial injury from infarction. Wall thickness and thickening were assessed from 3D personalized cardiac models reconstructed from cine MRI images by fitting inscribed sphere between endocardial and epicardial wall. The thickening analysis was performed in 5 patients and 3 healthy subjects and the results were compared against the gold standard 2D late-gadolinium-enhanced (LGE) images for infarct localization. The notable finding of this study is the highly accurate estimation and visual representation of the infarct size and location in 3D. This study provides clinicians with an intuitive way to visually and qualitatively assess regional cardiac wall dysfunction due to infarction in AMI patients.

  7. Strength and Stability Analysis of a Single Walled Black Phosphorus Tube under Axial Compression

    OpenAIRE

    Cai, Kun; Wan, Jing; Wei, Ning; Qin, Qinghua

    2016-01-01

    Few-layered black phosphorus materials recently attract much attention due to its special electronic properties. As a Consequence, the nano-tube from a single-layer black phosphorus has been theoretically built. The corresponding electronic properties of such black phosphorus nano-tube were also evaluated numerically.

  8. Methods of Investigation of Equations that Describe Waves in Tubes with Elastic Walls and Application of the Theory of Reversible and Weak Dissipative Shocks

    Science.gov (United States)

    Bakholdin, Igor

    2018-02-01

    Various models of a tube with elastic walls are investigated: with controlled pressure, filled with incompressible fluid, filled with compressible gas. The non-linear theory of hyperelasticity is applied. The walls of a tube are described with complete membrane model. It is proposed to use linear model of plate in order to take the bending resistance of walls into account. The walls of the tube were treated previously as inviscid and incompressible. Compressibility of material of walls and viscosity of material, either gas or liquid are considered. Equations are solved numerically. Three-layer time and space centered reversible numerical scheme and similar two-layer space reversible numerical scheme with approximation of time derivatives by Runge-Kutta method are used. A method of correction of numerical schemes by inclusion of terms with highorder derivatives is developed. Simplified hyperbolic equations are derived.

  9. The role of the velocity gradient in laminar convective heat transfer through a tube with a uniform wall heat flux

    International Nuclear Information System (INIS)

    Wang Liangbi; Zhang Qiang; Li Xiaoxia

    2009-01-01

    This paper aims to contribute to a better understanding of convective heat transfer. For this purpose, the reason why thermal diffusivity should be placed before the Laplacian operator of the heat flux, and the role of the velocity gradient in convective heat transfer are analysed. The background to these analyses is that, when the energy conservation equation of convective heat transfer is used to explain convective heat transfer there are two points that are difficult for teachers to explain and for undergraduates to understand: thermal diffusivity is placed before the Laplacian operator of temperature; on the wall surface (the fluid side) the velocity is zero, a diffusion equation of temperature is gained from energy conservation equation, however, temperature cannot be transported. Consequently, the real physical meaning of thermal diffusivity is not clearly reflected in the energy conservation equation, and whether heat transfer occurs through a diffusion process or a convection process on the wall surface is not clear. Through a simple convective heat transfer case: laminar convective heat transfer in a tube with a uniform wall heat flux on the tube wall, this paper explains these points more clearly. The results declare that it is easier for teachers to explain and for undergraduates to understand these points when a description of heat transfer in terms of the heat flux is used. In this description, thermal diffusivity is placed before the Laplacian operator of the heat flux; the role of the velocity gradient in convective heat transfer appears, on the wall surface, the fact whether heat transfer occurs through a diffusion process or a convection process can be explained and understood easily. The results are not only essential for teachers to improve the efficiency of university-level physics education regarding heat transfer, but they also enrich the theories for understanding heat transfer

  10. Sonographic assessment of splanchnic arteries and the bowel wall

    Energy Technology Data Exchange (ETDEWEB)

    Dietrich, C.F. [Medical Department II, Caritas-Krankenhaus, Uhlandstr. 7, D-97980 Bad Mergentheim (Germany)], E-mail: Christoph.dietrich@ckbm.de; Jedrzejczyk, M.; Ignee, A. [Medical Department II, Caritas-Krankenhaus, Uhlandstr. 7, D-97980 Bad Mergentheim (Germany)

    2007-11-15

    The intestinal wall can be visualized using high resolution transabdominal ultrasound. The normal intestinal wall thickness in the terminal ileum, cecum, and right and left colon is <2 mm when examined with graded compression. It is important to appreciate that a contracted intestinal segment can be misinterpreted as a thickened wall. Vascularisation can be mainly displayed in the second hyperechoic layer (submucosal layer) as well as vessels penetrating the muscularis propria. Imaging of the gastrointestinal wall is dependent on the experience of the examiner as well dependent on the equipment used. Acute or chronic inflammation of the intestinal wall is accompanied by increased perfusion of the mesentery, which can be displayed non-quantitatively with colour duplex. In contrast, ischemia is characterised by hypoperfusion of the mesenteric arteries and the bowel wall. The most promising sonographic approach in assessing splanchnic arteries and the bowel wall is combining the analysis of superior and inferior mesenteric inflow by pulsed Doppler scanning (systolic and diastolic velocities, resistance index) with the end-organ vascularity by colour Doppler imaging diminishing the influence of examination technique only displaying bowel wall vascularity. Colour Doppler imaging has been described as helpful in a variety of gastrointestinal disorders, particularly in patients with Crohn's disease, celiac disease, mesenteric artery stenosis and other ischemic gastrointestinal diseases, graft versus host disease and hemorrhagic segmental colitis.

  11. Assessment and management of ageing of major nuclear power plant components important to safety: CANDU pressure tubes

    International Nuclear Information System (INIS)

    1998-08-01

    The report documents the current practices for assessment and management of the ageing of the pressure tubes in CANDU reactors and Indian PHWTRs. Chapter headings are: fuel channel and pressure tube description, design basis for the fuel channel and pressure tube, degradation mechanisms and ageing concerns for pressure tubes, inspection and monitoring methods for pressure tubes,assessment methods and fitness-for-service guidelines for pressure tubes, mitigation methods for pressure tubes, and pressure tube ageing management programme

  12. Heat transfer augmentation along the tube wall of a louvered fin heat exchanger using practical delta winglets

    Energy Technology Data Exchange (ETDEWEB)

    Lawson, Michael J.; Thole, Karen A. [Mechanical and Nuclear Engineering Department, The Pennsylvania State University, University Park, PA 16802 (United States)

    2008-05-15

    Delta winglets are known to induce the formation of streamwise vortices and increase heat transfer between a working fluid and the surface on which the winglets are placed. This study investigates the use of delta winglets to augment heat transfer on the tube surface of louvered fin heat exchangers. It is shown that delta winglets placed on louvered fins produce augmentations in heat transfer along the tube wall as high as 47% with a corresponding increase of 19% in pressure losses. Manufacturing constraints are considered in this study whereby piercings in the louvered fins resulting from stamping the winglets into the louvered fins are simulated. Comparisons of measured heat transfer coefficients with and without piercings indicate that piercings reduce average heat transfer augmentations, but significant increases still occur with respect to no winglets present. (author)

  13. Bioactive surface modifications on inner walls of poly-tetra-fluoro-ethylene tubes using dielectric barrier discharge

    Science.gov (United States)

    Cho, Yong Ki; Park, Daewon; Kim, Hoonbae; Lee, Hyerim; Park, Heonyong; Kim, Hong Ja; Jung, Donggeun

    2014-03-01

    Bioactive surface modification can be used in a variety of medical polymeric materials in the fields of biochips and biosensors, artificial membranes, and vascular grafts. In this study, the surface modification of the inner walls of poly-tetra-fluoro-ethylene (PTFE) tubing was carried out to improve vascular grafts, which are made of biocompatible material for the human body in the medical field. Focus was centered on the cell attachment of the inner wall of the PTFE by sequential processes of hydrogen plasma treatment, hydrocarbon deposition, and reactive plasma treatment on the PFTE surface using micro plasma discharge. Micro plasma was generated by a medium-frequency alternating current high-voltage generator. The preliminary modification of PTFE was conducted by a plasma of hydrogen and argon gases. The hydrocarbon thin film was deposited on modified PTFE with a mixture of acetylene and argon gases. The reactive plasma treatment using oxygen plasma was done to give biocompatible functionality to the inner wall surface. The hydrophobic surface of bare PTFE is made hydrophilic by the reactive plasma treatment due to the formation of carbonyl groups on the surface. The reactive treatment could lead to improved attachment of smooth muscle cells (SMCs) on the modified PTFE tubing. Fourier transform infrared absorption spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and water contact angle measurement were used for the analysis of the surface modification. The SMC-attached PTFE tube developed will be applicable to in vitro human vasculature-mimetic model systems, and to medical vascular grafts.

  14. The effect of water jet lancing on furnace wall tubes of high slagged deposit fuel-fired boilers

    Energy Technology Data Exchange (ETDEWEB)

    Vasiliev, V V; Kovalevitch, I A; Maidanik, M N [All-Union Heat Engineering Institute, Siberian Branch, Krasnoyarsk (USSR)

    1990-01-01

    In this paper the results of investigating the effectiveness of water jet lancing on furnace wall tubes of slagged deposits fuels fired boilers type E-500, P-64, P-67 are given. The boilers of these types are designed to burn Jugoslavian lignites are Beresovo lignites of the Kansk-Achinsk deposits. Recommendations for usage of low retractable, long retractable and long-range water blowers, depending on the design, produced in the USSR, the furnace dimension and stability of deposits are given as well.

  15. Complete Status Report Documenting Development of Friction Stir Welding for Joining Thin Wall Tubing of ODS Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hoelzer, David T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bunn, Jeffrey R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-08-01

    The development of friction stir welding (FSW) for joining thin sections of the advanced oxide dispersion strengthened (ODS) 14YWT ferritic alloy was initiated in Fuel Cycle Research and Development (FCRD), now the Nuclear Technology Research and Development (NTRD), in 2015. The first FSW experiment was conducted in late FY15 and successfully produced a bead-on-plate stir zone (SZ) on a 1 mm thick plate of 14YWT (SM13 heat). The goal of this research task is to ultimately demonstrate that FSW is a feasible method for joining thin wall (0.5 mm thick) tubing of 14YWT.

  16. Dynamic behavior of radiant cooling system based on capillary tubes in walls made of high performance concrete

    DEFF Research Database (Denmark)

    Mikeska, Tomás; Svendsen, Svend

    2015-01-01

    elements made of high performance concrete. The influence of the radiant cooling system on the indoor climate of the test room in terms of the air, surface and operative temperatures and velocities was investigated.The results show that the temperature of the room air can be kept in a comfortable range...... using cooling water for the radiant cooling system with a temperature only about 4K lower than the temperature of the room air. The relatively high speed reaction of the designed system is a result of the slim construction of the sandwich wall elements made of high performance concrete. (C) 2015...... the small amount of fresh air required by standards to provide a healthy indoor environment.This paper reports on experimental analyses evaluating the dynamic behavior of a test room equipped with a radiant cooling system composed of plastic capillary tubes integrated into the inner layer of sandwich wall...

  17. Theoretical Analysis of Effects of Wall Suction on Entropy Generation Rate in Laminar Condensate Layer on Horizontal Tube

    Directory of Open Access Journals (Sweden)

    Tong-Bou Chang

    2014-01-01

    Full Text Available The effects of wall suction on the entropy generation rate in a two-dimensional steady film condensation flow on a horizontal tube are investigated theoretically. In analyzing the liquid flow, the effects of both the gravitational force and the viscous force are taken into account. In addition, a film thickness reduction ratio, Sf, is introduced to evaluate the effect of wall suction on the thickness of the condensate layer. The analytical results show that, the entropy generation rate depends on the Jakob number Ja, the Rayleigh number Ra, the Brinkman number Br, the dimensionless temperature difference ψ, and the wall suction parameter Sw. In addition, it is shown that in the absence of wall suction, a closed-form correlation for the Nusselt number can be derived. Finally, it is shown that the dimensionless entropy generation due to heat transfer, NT, increases with an increasing suction parameter Sw, whereas the dimensionless entropy generation due to liquid film flow friction, NF, decreases.

  18. Noninvasive assessment of right ventricular wall motion by radionuclide cardioangiography

    International Nuclear Information System (INIS)

    Nishimura, Tsunehiko; Uehara, Toshiisa; Naito, Hiroaki; Hayashida, Kohei; Kozuka, Takahiro

    1981-01-01

    Radionuclide cardioangiography is a useful method to evaluate the left ventricular wall motion in various heart diseases. It has been also attempted to assess the right ventricular wall motion simultaneously by radionuclide method. In this study, using the combination of first-pass (RAO 30 0 ) and multi-gate (LAO 40 0 ) method, the site of right vetricle was classified in five. (1 inflow, 2 sinus, 3 outflow, 4 septal, 5 lateral) and the degree of wall motion was classified in four stages (dyskinesis, akinesis, hypokinesis, normal) according to the AHA committee report. These methods were applied clinically to forty-eight patients with various heart diseases. In the cases with right ventricular pressure or volume overload such as COLD, pulmonary infarction, the right ventricle was dilated and the wall motion was reduced in all portions. Especially, in the cases with right ventricular infarction, the right ventricular wall motion was reduced in the infarcted area. The findings of radionuclide method were in good agreement with those of contrast right ventriculography or echocardiography. In conclusion, radionuclide cardioangiography is a useful and noninvasive method to assess not only the left but also the right ventricular wall motion. (author)

  19. Fatigue of thin walled tubes in copper alloy CuNi10

    DEFF Research Database (Denmark)

    Lambertsen, Søren Heide; Damkilde, Lars; Jepsen, Michael S.

    2016-01-01

    The current work concerns the investigation of the fatigue resistance of CuNi10 tubes, which are frequently used in heat exchangers of large ship engines. The lifetime performances of the exchanger tubes are greatly affected by the environmental conditions, where especially the temperature...... by means of the ASTM E739 guideline and one-sided tolerance limits factor method. The tests show good fatigue resistance and the risk for a failure is low in aspect to the case of a ship heat exchanger....

  20. Effects of tube diameter and chirality on the stability of single-walled carbon nanotubes under ion irradiation

    International Nuclear Information System (INIS)

    Xu Zijian; Zhang Wei; Zhu Zhiyuan; Ren Cuilan; Li Yong; Huai Ping

    2009-01-01

    Using molecular dynamics method, we investigated the influence of tube diameter and chirality on the stability of single-walled carbon nanotubes (CNTs) under ion irradiation. We found that in the energy range below 1 keV, the dependence of CNT stability on the tube diameter is no longer monotonic under C ion irradiation, and the thinner (5, 5) CNT may be more stable than the thicker (7, 7) CNT, while under Ar irradiation, the CNT stability increases still monotonically with the CNT diameter. This stability behavior was further verified by the calculations of the threshold ion energies to produce displacement damage in CNTs. The abnormal stability of thin CNTs is related to their resistance to the instantaneous deformation in the wall induced by ion pushing, the high self-healing capacity, as well as the different interaction properties of C and Ar ions with CNT atoms. We also found that under ion irradiation the stability of a zigzag CNT is better than that of an armchair CNT with the same diameter. This is because of the bonding structure difference between the armchair and the zigzag CNTs with respect to the orientations of graphitic networks as well as the self-healing capacity difference.

  1. Design of welding parameters for laser welding of thin-walled stainless steel tubes using numerical simulation

    Science.gov (United States)

    Nagy, M.; Behúlová, M.

    2017-11-01

    Nowadays, the laser technology is used in a wide spectrum of applications, especially in engineering, electronics, medicine, automotive, aeronautic or military industries. In the field of mechanical engineering, the laser technology reaches the biggest increase in the automotive industry, mainly due to the introduction of automation utilizing 5-axial movements. Modelling and numerical simulation of laser welding processes has been exploited with many advantages for the investigation of physical principles and complex phenomena connected with this joining technology. The paper is focused on the application of numerical simulation to the design of welding parameters for the circumferential laser welding of thin-walled exhaust pipes from theAISI 304 steel for automotive industry. Using the developed and experimentally verified simulation model for laser welding of tubes, the influence of welding parameters including the laser velocity from 30 mm.s-1 to 60 mm.s-1 and the laser power from 500 W to 1200 W on the temperature fields and dimensions of fusion zone was investigated using the program code ANSYS. Based on obtained results, the welding schedule for the laser beam welding of thin-walled tubes from the AISI 304 steel was suggested.

  2. Failure assessment and evaluation of critical crack length for a fresh Zr-2 pressure tube of an Indian PHWR

    International Nuclear Information System (INIS)

    Krishnan, Suresh; Bhasin, Vivek; Kushwaha, H.S.; Mahajan, S.C.; Kakodkar, A.

    1996-01-01

    Fracture analysis of Zr-2 pressure tubes having through wall axial crack was done using finite element method. The analysis was done for tubes in as received condition. During reactor operation the mechanical properties of Zr-2 undergo changes. The analysis is valid for pressure tubes of newly commissioned reactors. The main aim of the study was to determine critical crack length of pressure tubes in normal operating conditions. Elastic plastic fracture analysis was done for different crack lengths to determine applied J-integral values. Tearing modulus instability concept was used to evaluate critical crack length. One of the important parameter studied was, the effect of crack face pressure, which leaking fluid exert on the crack faces/lips of through wall axial crack. Its effect was found to be significant for pressure tubes. It increases the applied J-integral values. Approximate analytical solutions which takes into account the plasticity ahead of crack tip, are available and widely used. These formulae do not take into account the crack face pressure. Since, for the present situation the effect of crack face pressure is significant hence, detailed finite analysis was necessary. Detailed 3D finite element analysis gives an insight into the variation of J-integral values over the thickness of pressure tube. It was found that J values are maximum at the middle layer of the tube. A peak factor on J values was defined and evaluated as ratio of maximum J to average J across the thickness, crack opening area for each length was also evaluated. The knowledge of crack opening area is useful for leak before break studies. The failure assessment was also done using Central Electricity Generating Board (CEGB) R-6 method considering the ductile tearing. The reserve factors (or safety margins) for different crack lengths was evaluated using R-6 method. (author). 30 refs., 21 figs., 34 tabs

  3. A Study On Critical Thinning In Thin-walled Tube Bending Of Al-Alloy 5052O Via Coupled Ductile Fracture Criteria

    International Nuclear Information System (INIS)

    Li Heng; Yang He; Zhan Mei

    2010-01-01

    Thin-walled tube bending(TWTB) method of Al-alloy tube has attracted wide applications in aerospace, aviation and automobile,etc. While, under in-plane double tensile stress states at the extrados of bending tube, the over-thinning induced ductile fracture is one dominant defect in Al-alloy tube bending. The main objective of this study is to predict the critical wall-thinning of Al-alloy tube bending by coupling two ductile fracture criteria(DFCs) into FE simulation. The DFCs include Continuum Damage Mechanics(CDM)-based model and GTN porous model. Through the uniaxial tensile test of the curved specimen, the basic material properties of the Al-alloy 5052O tube is obtained; via the inverse problem solution, the damage parameters of both the two fracture criteria are interatively determined. Thus the application study of the above DFCs in the TWTB is performed, and the more reasonable one is selected to obtain the critical thinning of Al-alloy tube in bending. The virtual damage initiation and evolution (when and where the ductile fracture occurs) in TWTB are investigated, and the fracture mechanisms of the voided Al-alloy tube in tube bending are consequently discussed.

  4. Strategy for assessment of WWER steam generator tube integrity. Report prepared within the framework of the coordinated research project on verification of WWER steam generator tube integrity

    International Nuclear Information System (INIS)

    2007-12-01

    Steam generator heat exchanger tube degradations happen in WWER Nuclear Power Plant (NPP). The situation varies from country to country and from NPP to NPP. More severe degradation is observed in WWER-1000 NPPs than in case of WWER-440s. The reasons for these differences could be, among others, differences in heat exchanger tube material (chemical composition, microstructure, residual stresses), in thermal and mechanical loadings, as well as differences in water chemistry. However, WWER steam generators had not been designed for eddy current testing which is the usual testing method in steam generators of western PWRs. Moreover, their supplier provided neither adequate methodology and criteria nor equipment for planning and implementing In-Service Inspection (ISI). Consequently, WWER steam generator ISI infrastructure was established with delay. Even today, there are still big differences in the eddy current inspection strategy and practice as well as in the approach to steam generator heat exchanger tube structural integrity assessment (plugging criteria for defective tubes vary from 40 to 90% wall thickness degradation). Recognizing this situation, the WWER operating countries expressed their need for a joint effort to develop methodology to establish reasonable commonly accepted integrity assessment criteria for the heat exchanger tubes. The IAEA's programme related to steam generator life management is embedded into the systematic activity of its Technical Working Group on Life Management of Nuclear Power Plants (TWG-LMNPP). Under the advice of the TWG-LMNPP, an IAEA coordinated research project (CRP) on Verification of WWER Steam Generator Tube Integrity was launched in 2001. It was completed in 2005. Thirteen organizations involved in in-service inspection of steam generators in WWER operating countries participated: Croatia, Czech Republic, Finland, France, Hungary, Russian Federation, Slovakia, Spain, Ukraine, and the USA. The overall objective was to

  5. Single-Walled Carbon Nano tubes as Fluorescence Biosensors for Pathogen Recognition in Water Systems

    International Nuclear Information System (INIS)

    Upadhyayula, V.K.K

    2008-01-01

    The possibility of using single-walled carbon nanotubes (SWCNTs) aggregates as fluorescence sensors for pathogen recognition in drinking water treatment applications has been studied. Batch adsorption study is conducted to adsorb large concentrations of Staphylococcus aureus aureus SH 1000 and Escherichia coli pKV-11 on single-walled carbon nanotubes. Subsequently the immobilized bacteria are detected with confocal microscopy by coating the nanotubes with fluorescence emitting antibodies. The Freundlich adsorption equilibrium constant (k) for S.aureus and E.coli determined from batch adsorption study was found to be 9 x108 and 2 x108 ml/g, respectively. The visualization of bacterial cells adsorbed on fluorescently modified carbon nanotubes is also clearly seen. The results indicate that hydrophobic single-walled carbon nanotubes have excellent bacterial adsorption capacity and fluorescent detection capability. This is an important advancement in designing fluorescence biosensors for pathogen recognition in water systems.

  6. Fragility assessment method of Concrete Wall Subjected to Impact Loading

    International Nuclear Information System (INIS)

    Hahm, Daegi; Shin, Sang Shup; Choi, In-Kil

    2014-01-01

    These studies have been aimed to verify and ensure the safety of the targeted walls and structures especially in the viewpoint of the deterministic approach. However, recently, the regulation and the assessment of the safety of the nuclear power plants (NPPs) against to an aircraft impact are strongly encouraged to adopt a probabilistic approach, i.e., the probabilistic risk assessment of an aircraft impact. In Korea, research to develop aircraft impact risk quantification technology was initiated in 2012 by Korea Atomic Energy Research Institute (KAERI). In this paper, for the one example of the probabilistic safety assessment approach, a method to estimate the failure probability and fragility of concrete wall subjected to impact loading caused by missiles or engine parts of aircrafts will be introduced. This method and the corresponding results will be used for the total technical roadmap and the procedure to assess the aircraft impact risk (Fig.1). A method and corresponding results of the estimation of the failure probability and fragility for a concrete wall subjected to impact loadings caused by missiles or engine parts of aircrafts was introduced. The detailed information of the target concrete wall in NPP, and the example aircraft engine model is considered safeguard information (SGI), and is not contained in this paper

  7. Assessment of a Pressure Tube Rupture with a Poisoned Moderator

    International Nuclear Information System (INIS)

    Kim, S. R.; Kim, B. G.; Kim, S. C.; Kim, E. K.

    2005-01-01

    The postulated in-core LOCA has been analyzed and evaluated while the reactor is operating normally with a low moderator poison concentration for CANDU. However, when the reactor is operating with a relatively large amount of boron and/or gadolinium poison in the moderator, an assessment of the fuel integrity was required for the pressure tube rupture (PTR) accident. Poisoned moderator exists mainly during a startup after a prolonged shutdown lasting for more than one day. For the case of a reactor regulating system (RRS) working, the methodology of the PTR assessment with a poisoned moderator has been developed to determine the effective trip parameters, evaluate the fuel integrity, and establish the standard reactor start-up model for the Wolsong Nuclear Power Plants recently. The developed methodology and results are presented

  8. Thermodynamic optimization of a coiled tube heat exchanger under constant wall heat flux condition

    International Nuclear Information System (INIS)

    Satapathy, Ashok K.

    2009-01-01

    In this paper the second law analysis of thermodynamic irreversibilities in a coiled tube heat exchanger has been carried out for both laminar and turbulent flow conditions. The expression for the scaled non-dimensional entropy generation rate for such a system is derived in terms of four dimensionless parameters: Prandtl number, heat exchanger duty parameter, Dean number and coil to tube diameter ratio. It has been observed that for a particular value of Prandtl number, Dean number and duty parameter, there exists an optimum diameter ratio where the entropy generation rate is minimum. It is also found that with increase in Dean number or Reynolds number, the optimum value of the diameter ratio decreases for a particular value of Prandtl number and heat exchanger duty parameter.

  9. Development and quality assessments of commercial heat production of ATF FeCrAl tubes

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-09-01

    Development and quality assessment of the 2nd generation ATF FeCrAl tube production with commercial manufacturers were conducted. The manufacturing partners include Sophisticated Alloys, Inc. (SAI), Butler, PA for FeCrAl alloy casting via vacuum induction melting, Oak Ridge National Laboratory (ORNL) for extrusion process to prepare the master bars/tubes to be tube-drawn, and Rhenium Alloys, Inc. (RAI), North Ridgeville, OH, for tube-drawing process. The masters bars have also been provided to Los Alamos National Laboratory (LANL) who works with Century Tubes, Inc., (CTI), San Diego, CA, as parallel tube production effort under the current program.

  10. Sucrose Synthase Is Associated with the Cell Wall of Tobacco Pollen Tubes

    NARCIS (Netherlands)

    Persia, D.; Cai, G.; Casino, C.; Willemse, M.T.M.; Cresti, M.

    2008-01-01

    Sucrose synthase (Sus; EC 2.4.1.13) is a key enzyme of sucrose metabolism in plant cells, providing carbon for respiration and for the synthesis of cell wall polymers and starch. Since Sus is important for plant cell growth, insights into its structure, localization, and features are useful for

  11. SPONTANEOUS FALLOPIAN TUBE EVISCERATION IN PROCIDENTIA AND PERFORATING CARCINOMATOUS VAGINAL WALL ULCER – CASE REPORT

    Directory of Open Access Journals (Sweden)

    Marijan Lužnik

    2018-02-01

    Full Text Available Background. Total prolapse of female pelvic organs is not only painful and troublesome because of difficulties with micturition and defecation but it could be very dangerous since prolapsed vagina presents a predilection area for ulcer and/or rupture of different etiology and with evisceration of abdominal content. Eviscerations usually occur rarely, but when they do occur, it is important to intervene quickly. Most frequent is the evisceration of small bowel, rarely omentum and sporadically other abdominal structures. Neither in literature nor on the internet there were not any examples of primary eviscerated fallopian tube which was not a consequence of preceeding gynecological-surgical procedure found. Methods. 77-year-old woman was appointed to our out patient department with diagnosis of Prolapsus uteri totalis and Dolores abdominalis. In history there was prevulvar bulge in the size of an apple, which persisted for 20 years, and almost disappeared when lying supine. Three days before admission to the hospital the bulge was exceedingly enlarged by straining and did not diminish when lying supine. The patient walked only hardly and could not sit. Micturition and defecation was possible only in the upright position. There were also difficulties while placing the patient on a gynecologic chair, because between her legs there was a bulge in the size of 14 × 10 × 9 cm3 with fallopian tube hanging out (Figure 1. On the outermost part of total uterovaginal prolapse the outer ostium of the cervical canal was recognizable. The bulge was fully stretched, painful and unreponible. Around a hole where a fallopian tube exits, vagina was eritematous, rough folded – swollen and vulnerable (Figure 2. In outpatient department eviscerated fallopian tube and prolapsed vagina with its contents were aseptically treated and Dalacin and Orho Gynest crème were applicated. Foley catheter was inserted. Prolapsed vagina with uterus and other contents remained

  12. Characterization of mechanical properties of hydroxyapatite-silicon-multi walled carbon nano tubes composite coatings synthesized by EPD on NiTi alloys for biomedical application.

    Science.gov (United States)

    Khalili, Vida; Khalil-Allafi, Jafar; Sengstock, Christina; Motemani, Yahya; Paulsen, Alexander; Frenzel, Jan; Eggeler, Gunther; Köller, Manfred

    2016-06-01

    Release of Ni(1+) ions from NiTi alloy into tissue environment, biological response on the surface of NiTi and the allergic reaction of atopic people towards Ni are challengeable issues for biomedical application. In this study, composite coatings of hydroxyapatite-silicon multi walled carbon nano-tubes with 20wt% Silicon and 1wt% multi walled carbon nano-tubes of HA were deposited on a NiTi substrate using electrophoretic methods. The SEM images of coated samples exhibit a continuous and compact morphology for hydroxyapatite-silicon and hydroxyapatite-silicon-multi walled carbon nano-tubes coatings. Nano-indentation analysis on different locations of coatings represents the highest elastic modulus (45.8GPa) for HA-Si-MWCNTs which is between the elastic modulus of NiTi substrate (66.5GPa) and bone tissue (≈30GPa). This results in decrease of stress gradient on coating-substrate-bone interfaces during performance. The results of nano-scratch analysis show the highest critical distance of delamination (2.5mm) and normal load before failure (837mN) as well as highest critical contact pressure for hydroxyapatite-silicon-multi walled carbon nano-tubes coating. The cell culture results show that human mesenchymal stem cells are able to adhere and proliferate on the pure hydroxyapatite and composite coatings. The presence of both silicon and multi walled carbon nano-tubes (CS3) in the hydroxyapatite coating induce more adherence of viable human mesenchymal stem cells in contrast to the HA coated samples with only silicon (CS2). These results make hydroxyapatite-silicon-multi walled carbon nano-tubes a promising composite coating for future bone implant application. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Assessing forest resources in Denmark using wall-to-wall remote sensing data

    DEFF Research Database (Denmark)

    Schumacher, Johannes

    then be applied to estimate resources on both small and large scales. Numerous studies have investigated the possibilities of using remote sensing data for forest monitoring at plot or single tree levels. However, experience of estimating these properties for larger areas, for example regional or country...... assessments, is lacking. In this thesis wall-to-wall remote sensing data (from aerial images, airborne LiDAR, and space-borne SAR) were combined with ground reference data (from NFI plots and tree species experiments) to build and evaluate models estimating properties such as basal area, timber volume......, the thesis extends the application of remote sensing methods to estimate important variables with relevance to water catchment management....

  14. Standard guide for mutual inductance bridge applications for wall thickness determinations in boiler tubing

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This guide describes a procedure for obtaining relative wall thickness indications in ferromagnetic and non-ferromagnetic steels using the mutual inductance bridge method. The procedure is intended for use with instruments capable of inducing two substantially identical magnetic fields and noting the change in inductance resulting from differing amounts of steel. It is used to distinguish acceptable wall thickness conditions from those which could place tubular vessels or piping at risk of bursting under high temperature and pressure conditions. 1.2 This guide is intended to satisfy two general needs for users of industrial Mutual Inductance Bridge (MIB) equipment: (1) the need for a tutorial guide addressing the general principles of Mutual Inductance Bridges as they apply to industrial piping; and (2) the need for a consistent set of MIB performance parameter definitions, including how these performance parameters relate to MIB system specifications. Potential users and buyers, as well as experienced M...

  15. Assessment of corrosion failure in copper tube of refrigerator unit

    International Nuclear Information System (INIS)

    Mohd Harun; Hafizal Yazid; Zaiton Selamat; Mohd Shariff Sattar; Muhamamd Jalil

    2007-01-01

    The copper tubes of the refrigerator unit have been coated with red and white color paints. According to the date of purchase and complaint recorded, the tube leaked after operation about one year. It was observed that the tubes became black and green in color at U-bend of the tube. No corrosion occurred on the internal surface of the tube. The leaking started at outer surface of the tube. The leaking started at outer surface and propagated to the internal surface of the tubes. The leaking damage was caused by corrosive species either from atmospheric corrosion or the paint contained chloride and sulfur elements. The corrosive species of sulfur and chlorine were a main factor in pitting corrosion. (author)

  16. Stress in closed thin-walled tubes of single box subjected by shear forces and application to airfoils

    Directory of Open Access Journals (Sweden)

    Zebbiche Toufik

    2014-09-01

    Full Text Available The presented work is to develop a numerical computation program to determine the distribution of the shear stress to shear in closed tubes with asymmetric single thin wall section with a constant thickness and applications to airfoils and therefore determining the position and value of the maximum stress. In the literature, there are exact analytical solutions only for some sections of simple geometries such as circular section. Hence our interest is focused on the search of approximate numerical solutions for more complex sections used in aeronautics. In the second stage the position of the shear center is determined so that the section does not undergo torsion. The analytic function of the boundary of the airfoil is obtained by using the cubic spline interpolation since it is given in the form of tabulated points.

  17. The Effect of DNA and Sodium Cholate Dispersed Single-Walled Carbon Nano tubes on the Green Algae Chlamydomonas reinhardtii

    International Nuclear Information System (INIS)

    Williams, R.M.; Cox, Z.; Dolash, B.D.; Sooter, L.J.; Williams, R.M.; Taylor, H.K.; Thomas, J.

    2014-01-01

    Increasing use of single-walled carbon nano tubes (SWCNTs) will lead to their increased release into the environment. Previous work has shown negative effects of SWCNT on growth and survival of model organisms. The aim of the current study was to determine the effect of SWCNT well-dispersed by either DNA or sodium cholate (SC) on the unicellular green algae Chlamydomonas reinhardtii in stagnant water conditions. Growth measurements were taken up to ten days for algae treated with varied levels of DNA:SWCNT or SC:SWCNT or controls, and chlorophyll content after 10 days was determined. Results show no effect on either growth or chlorophyll content of algae at any concentration or duration. This is in contradiction to prior work showing toxicity of SWCNT to environmental model organisms.

  18. An assessment for the erosion rate of DEMO first wall

    Science.gov (United States)

    Tokar, M. Z.

    2018-01-01

    In a fusion reactor a significant fraction of plasma particles lost from the confined volume will reach the vessel wall. The recombination of these charged species, electrons and ions of hydrogen isotopes, is a source of neutral molecules and atoms, recycling back into the plasma. Here they participate, in particular, in charge-exchange (c-x) collisions with the plasma ions and, as a result, atoms of high energies with chaotically oriented velocities are generated. A significant fraction of these hot neutrals will hit the wall, leading, as well as the outflowing fuel and impurity ions, to its erosion, limiting the reactor operation time. The rate of the wall erosion in DEMO is assessed by applying a one-dimensional model which takes into account the transport of charged and neutral species across the flux surfaces in the main part of the scrape-off layer, beyond the X-point vicinity and divertor, and by considering the shift of the centers of flux surfaces, their elongation and triangularity. Atoms generated by c-x of recycling neutrals are modeled kinetically to define firmly their energy spectrum, being of particular importance for the erosion assessment. It is demonstrated the erosion rate of the DEMO wall armor of tungsten will have a pronounced ballooning character with a significant maximum of 0.3 mm per full power year at the low field side, decreasing with an increase in the anomalous perpendicular transport in the ‘far’ SOL or the plasma density at the separatrix.

  19. Mathematical Model of Stress-Strain State of Curved Tube of Non-Circular Cross-Section with Account of Technological Wall Thickness Variation

    Science.gov (United States)

    Pirogov, S. P.; Ustinov, N. N.; Smolin, N. I.

    2018-05-01

    A mathematical model of the stress-strain state of a curved tube of a non-circular cross-section is presented, taking into account the technological wall thickness variation. On the basis of the semi-membrane shell theory, a system of linear differential equations describing the deformation of a tube under the effect of pressure is obtained. To solve the boundary value problem, the method of shooting is applied. The adequacy of the proposed mathematical model is verified by comparison with the experimental data and the results of the calculation of tubes by the energy method.

  20. Analysis of the ballooning deformation of an internally pressurized thin-wall tube during fast thermal transients

    International Nuclear Information System (INIS)

    Lin, E.I.H.

    1977-01-01

    A large-strain time-dependent thermoplastic analysis has been developed for the ballooning deformation of a thin-wall tube subjected to internal pressure, axial loading, and fast thermal transients. This deformation initiates with the onset of plastic instability in the material, the onset being determined by a plastic-instability criterion for strain-rate sensitive materials. The interaction among the local ballooning geometry, the state of stress, and the plastic flow process was considered, and integration of the flow equations yields the local curvature and the states of stress and strain in the vicinity of the maximum ballooning site. The effects of axial constraint and heating rate were also discussed. The analysis was applied to a LWR Zircaloy cladding subjected to a constant heating rate and a range of internal pressures. The results agree very well with experimental strain-time data obtained from tube-burst tests. In most cases, the time of rupture was accurately predicted despite the lack of complete material-property data

  1. Biliary peritonitis caused by a leaking T-tube fistula disconnected at the point of contact with the anterior abdominal wall: a case report

    Directory of Open Access Journals (Sweden)

    Nikolić Marko

    2008-09-01

    Full Text Available Abstract Introduction Operations on the common bile duct may lead to potentially serious complications such as biliary peritonitis. T-tube insertion is performed to reduce the risk of this occurring postoperatively. Biliary leakage at the point of insertion into the common bile duct, or along the fistula, can sometimes occur after T-tube removal and this has been reported extensively in the literature. We report a case where the site at which the T-tube fistula leaked proved to be the point of contact between the fistula and the anterior abdominal wall, a previously unreported complication. Case presentation A 36-year-old sub-Saharan African woman presented with gallstone-induced pancreatitis and, once her symptoms settled, laparoscopic cholecystectomy was performed, common bile duct stones were removed and a T-tube was inserted. Three weeks later, T-tube removal led to biliary peritonitis due to the disconnection of the T-tube fistula which was recannulated laparoscopically using a Latex drain. Conclusion This case highlights a previously unreported mechanism for bile leak following T-tube removal caused by detachment of a fistula tract at its contact point with the anterior abdominal wall. Hepatobiliary surgeons should be aware of this mechanism of biliary leakage and the use of laparoscopy to recannulate the fistula.

  2. Investigation on Nano composite Membrane of Multi walled Carbon Nano tube Reinforced Polycarbonate Blend for Gas Separation

    International Nuclear Information System (INIS)

    Kausar, A.

    2016-01-01

    Carbon nano tube has been explored as a nano filler in high performance polymeric membrane for gas separation. In this regard, nano composite membrane of polycarbonate (PC), poly(vinylidene fluoride-co-hexafluoropropylene) (PVFHFP), and multi walled carbon nano tube (MWCNT) was fabricated via phase inversion technique. Poly (ethylene glycol) (PEG) was employed for the compatibilization of the blend system. Two series of PC/PVFHFP/PEG were developed using purified P-MWCNT and acid functional A-MWCNT nano filler. Scanning and transmission electron micrographs have shown fine nano tube dispersion and wetting by matrix, compared with the purified system. Tensile strength and Young s modulus of PC/PVFHFP/PEG/MWCNT-A 1-5 were found to be in the range of 63.6-72.5 MPa and 110.6-122.1 MPa, respectively. The nano composite revealed 51% increase in Young s modulus and 28% increase in tensile stress relative to the pristine blend. The A-MWCNT was also effective in enhancing the perm selectivity αCO 2 /N 2 (31.2-39.9) of nano composite membrane relative to the blend membrane (21.6). The permeability ρCO 2 of blend was 125.6 barrer; however, the functional series had enhancedρCO 2 values ranging from 142.8 to 186.6 barrer. Moreover, A-MWCNT loading improved the gas diffusivity of PC/PVFHFP/PEG/MWCNT-A 1-5; however, filler content did not significantly influence the CO 2 and N 2 solubility.

  3. Failure analysis of large tube of maraging steel 350 (145 mm dia, 1 mm wall thickness)

    International Nuclear Information System (INIS)

    Shamim, A.

    1997-01-01

    A steady of opening mode of crack initiation in maraging steel 350 rotor tubes aged and rolled condition (1 mm thick sheet) has been constructed, with the aid of a (NEOPHOT 2) microscope. Observations were made from several orientations including the top view of the specimen which showed the profile and the edge view of the specimen which showed the entire notch front along the specimen thickness. It was found that the edge view exhibited the first signs of permanent deformation. These changes took the form of deformation bends which were aligned in direction of the tensile axis and apparently defined limiting regions of homogeneous slip. It is felt that the appearance of microcracks at loads approaching the breaking strength was of fundamental importance in the formation of the final fracture surface. Many of these microcracks were initiated at intermetallic particles and other metallurgically weak regions on the notch surface. (author)

  4. A comparison and assessment of approaches for modelling flow over in-line tube banks

    International Nuclear Information System (INIS)

    Iacovides, Hector; Launder, Brian; West, Alastair

    2014-01-01

    Highlights: • We present wall-resolved LES and URANS simulations of periodic flow in heated in-line tube banks. • Simulations of flow in a confined in-line tube-bank are compared with experimental data. • When pitch-to-diameter (P/D) ratio becomes less than 1.6, the periodic flow becomes skewed. • URANS tested here unable to mimic the periodic flow at P/D = 1.6. • In confined tube banks URANS suggest alternate, in the axial direction, flow deflection. - Abstract: The paper reports experiences from applying alternative strategies for modelling turbulent flow and local heat-transfer coefficients around in-line tube banks. The motivation is the simulation of conditions in the closely packed cross-flow heat exchangers used in advanced gas-cooled nuclear reactors (AGRs). The main objective is the flow simulation in large-scale tube banks with confining walls. The suitability and accuracy of wall-resolved large-eddy simulation (LES) and Unsteady Reynolds-Averaged Navier–Stokes (URANS) approaches are examined for generic, square, in-line tube banks, where experimental data are limited but available. Within the latter approach, both eddy-viscosity and Reynolds-stress-transport models have been tested. The assumption of flow periodicity in all three directions is investigated by varying the domain size. It is found that the path taken by the fluid through the tube-bank configuration differs according to the treatment of turbulence and whether the flow is treated as two- or three-dimensional. Finally, the important effect of confining walls has been examined by making direct comparison with the experiments of the complete test rig of Aiba et al. (1982)

  5. Assessment of need for transport tubes when continuously monitoring for radioactive aerosols.

    Science.gov (United States)

    Whicker, J J; Rodgers, J C; Lopez, R C

    1999-09-01

    Aerosol transport tubes are often used to draw aerosol from desirable sampling locations to nearby air sampling equipment that cannot be placed at that location. In many plutonium laboratories at Los Alamos National Laboratory, aerosol transport tubes are used to transport aerosol from the front of room ventilation exhaust registers to continuous air monitors (CAMs) that are mounted on nearby walls. Transport tubes are used because past guidance suggests that extraction of aerosol samples from exhaust locations provides the most sensitive and reliable detection under conditions where the rooms have unpredictable release locations and significant spatial variability in aerosol concentrations after releases, and where CAMs cannot be located in front of exhaust registers without blocking worker walkways. Despite designs to minimize particle loss in tubes, aerosol transport model predictions suggest losses occur lowering the sensitivity of CAMs to accidentally released plutonium aerosol. The goal of this study was to test the hypotheses that the reliability, speed, and sensitivity of aerosol detection would be equal whether the sample was extracted from the front of the exhaust register or from the wall location of CAMs. Polydisperse oil aerosols were released from multiple locations in two plutonium laboratories to simulate plutonium aerosol releases. Networked laser particle counters (LPCs) were positioned to simultaneously measure time-resolved aerosol concentrations at each exhaust register (representative of sampling with transport tubes) and at each wall-mounted CAM location (representative of sampling without transport tubes). Results showed no significant differences in detection reliability, speed, or sensitivity for LPCs positioned at exhaust locations when compared to LPCs positioned at the CAM wall location. Therefore, elimination of transport tubes would likely improve CAM performance.

  6. Radiographic testing methods for welds of thin titanium plates and thin wall tubes

    International Nuclear Information System (INIS)

    1984-01-01

    This standard stipulates the testing method by X-ray radiography for the welded parts of titanium plates and titanium tubes with thickness not exceeding 8 mm. The other items than those stipulated here shall be in accordance with JIS Z 3107-1973 ''Testing method by radiography for the welded part of titanium and method of grade classification of radiographs''. As the photographing method of radiographs, the performance of the equipment and materials for testing, the direction of X-ray irradiation, the thickness of parent materials and welds, the use of penetrameters, the arrangement for photographing, the requirement for radiographs and the observation of radiographs are specified. The X-ray apparatuses, photo-sensitive materials and the tools for photographing and observation must be such that the radiographs clearly showing the defects in the welds being tested can be taken or observed. The JIS Z 3107 is insufficient for the test of thin materials like titanium, therefore, this standard was set down. As the thickness of welds, the thickness of parent materials was taken. In this standard, the titanium penetrameters were adopted because they can be made and they conform to practical state. If magnified photographing is carried out with microfocus X-ray apparatuses, precise photographing can be made. (Kako, I.)

  7. Thin-walled composite tubes using fillers subjected to quasistatic axial compression

    International Nuclear Information System (INIS)

    AL-Qrimli, Haidar F; Mahdi, Fadhil A; Ismail, Firas B; Alzorqi, Ibrahim S

    2015-01-01

    It has been demonstrated that composites are lightweight, fatigue resistant and easily melded, a seemingly attractive alternative to metals. However, there has been no widespread switch from metals to composites in the automotive sector. This is because there are a number of technical issues relating to the use of composite materials that still need to be resolved including accurate material characterization, manufacturing and joining process. The total of 36 specimens have been fabricated using the fibre-glass and resin (epoxy) with a two different geometries (circular and corrugated) each one will be filled with five types of filler (Rice Husk, Wood Chips, Aluminium Chips, Coconut Fibre, Palm Oil Fibre) all these type will be compared with empty Tubes for circular and corrugated in order to comprehend the crashworthiness parameters (initial failure load, average load, maximum crushing load, load ratio, energy absorption, specific energy absorption, volumetric energy absorption, crushing force efficiency and crush strain relation) which are considered very sufficient parameters in the design of automotive industry parts. All the tests have been done using the “INSTRON Universal machine” which is computerized in order to simply give a high precision to the collection of the results, along with the use of quasi-static load to test and observe the behaviour of the fabricated specimens. (paper)

  8. Thin-walled composite tubes using fillers subjected to quasistatic axial compression

    Science.gov (United States)

    AL-Qrimli, Haidar F.; Mahdi, Fadhil A.; Ismail, Firas B.; Alzorqi, Ibrahim S.

    2015-04-01

    It has been demonstrated that composites are lightweight, fatigue resistant and easily melded, a seemingly attractive alternative to metals. However, there has been no widespread switch from metals to composites in the automotive sector. This is because there are a number of technical issues relating to the use of composite materials that still need to be resolved including accurate material characterization, manufacturing and joining process. The total of 36 specimens have been fabricated using the fibre-glass and resin (epoxy) with a two different geometries (circular and corrugated) each one will be filled with five types of filler (Rice Husk, Wood Chips, Aluminium Chips, Coconut Fibre, Palm Oil Fibre) all these type will be compared with empty Tubes for circular and corrugated in order to comprehend the crashworthiness parameters (initial failure load, average load, maximum crushing load, load ratio, energy absorption, specific energy absorption, volumetric energy absorption, crushing force efficiency and crush strain relation) which are considered very sufficient parameters in the design of automotive industry parts. All the tests have been done using the “INSTRON Universal machine” which is computerized in order to simply give a high precision to the collection of the results, along with the use of quasi-static load to test and observe the behaviour of the fabricated specimens.

  9. Analytic model of the stress waves propagation in thin wall tubes, seeking the location of a harmonic point source in its surface

    International Nuclear Information System (INIS)

    Boaratti, Mario Francisco Guerra

    2006-01-01

    Leaks in pressurized tubes generate acoustic waves that propagate through the walls of these tubes, which can be captured by accelerometers or by acoustic emission sensors. The knowledge of how these walls can vibrate, or in another way, how these acoustic waves propagate in this material is fundamental in the detection and localization process of the leak source. In this work an analytic model was implemented, through the motion equations of a cylindrical shell, with the objective to understand the behavior of the tube surface excited by a point source. Since the cylindrical surface has a closed pattern in the circumferential direction, waves that are beginning their trajectory will meet with another that has already completed the turn over the cylindrical shell, in the clockwise direction as well as in the counter clockwise direction, generating constructive and destructive interferences. After enough time of propagation, peaks and valleys in the shell surface are formed, which can be visualized through a graphic representation of the analytic solution created. The theoretical results were proven through measures accomplished in an experimental setup composed of a steel tube finished in sand box, simulating the condition of infinite tube. To determine the location of the point source on the surface, the process of inverse solution was adopted, that is to say, known the signals of the sensor disposed in the tube surface , it is determined through the theoretical model where the source that generated these signals can be. (author)

  10. Assessment of seismic design response factors of concrete wall buildings

    Science.gov (United States)

    Mwafy, Aman

    2011-03-01

    To verify the seismic design response factors of high-rise buildings, five reference structures, varying in height from 20- to 60-stories, were selected and designed according to modern design codes to represent a wide range of concrete wall structures. Verified fiber-based analytical models for inelastic simulation were developed, considering the geometric nonlinearity and material inelasticity of the structural members. The ground motion uncertainty was accounted for by employing 20 earthquake records representing two seismic scenarios, consistent with the latest understanding of the tectonic setting and seismicity of the selected reference region (UAE). A large number of Inelastic Pushover Analyses (IPAs) and Incremental Dynamic Collapse Analyses (IDCAs) were deployed for the reference structures to estimate the seismic design response factors. It is concluded that the factors adopted by the design code are adequately conservative. The results of this systematic assessment of seismic design response factors apply to a wide variety of contemporary concrete wall buildings with various characteristics.

  11. Moisture Durability Assessment of Selected Well-insulated Wall Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Pallin, Simon B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Boudreaux, Philip R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kehrer, Manfred [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hun, Diana E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jackson, Roderick K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Desjarlais, Andre Omer [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-12-01

    This report presents the results from studying the hygrothermal performance of two well-insulated wall assemblies, both complying with and exceeding international building codes (IECC 2015 2014, IRC 2015). The hygrothermal performance of walls is affected by a large number of influential parameters (e.g., outdoor and indoor climates, workmanship, material properties). This study was based on a probabilistic risk assessment in which a number of these influential parameters were simulated with their natural variability. The purpose of this approach was to generate simulation results based on laboratory chamber measurements that represent a variety of performances and thus better mimic realistic conditions. In total, laboratory measurements and 6,000 simulations were completed for five different US climate zones. A mold growth indicator (MGI) was used to estimate the risk of mold which potentially can cause moisture durability problems in the selected wall assemblies. Analyzing the possible impact on the indoor climate due to mold was not part of this study. The following conclusions can be reached from analyzing the simulation results. In a hot-humid climate, a higher R-value increases the importance of the airtightness because interior wall materials are at lower temperatures. In a cold climate, indoor humidity levels increase with increased airtightness. Air leakage must be considered in a hygrothermal risk assessment, since air efficiently brings moisture into buildings from either the interior or exterior environment. The sensitivity analysis of this study identifies mitigation strategies. Again, it is important to remark that MGI is an indicator of mold, not an indicator of indoor air quality and that mold is the most conservative indicator for moisture durability issues.

  12. Comparison of characteristics parameters in the evaluation of wall thickness diminishing in admiralty brass tubes of the steam condenser, tested by eddy currents

    International Nuclear Information System (INIS)

    Obrutsky, Alba E.; Mendez, Jorge A.; Acosta, Cesar D.; Scopelliti, Jose D.

    1999-01-01

    This work is aimed to appraise the measure of the wall thickness diminishing in the signals evaluation obtained in the inspection of steam condenser by eddy currents. In the analysis of the obtained signals were observed in the brass tubes a great quantity of internal defects whose signal indicates that there were diminishing of the wall thickness between 80% and 100%. With all this information and analyzing the data acquired, the tubes with more important indications were selected to make a more exhaustive study of the found defectology. As first test, it was measured the thickness of the worn tubes, comparing them with the original ones that are in stock. It was verified that the tubes separated for this study presented a 30% less thickness in comparison with the new tubes. A semiquantitative chemical test (EDAX) was made to verify if it was the same material. One of the extracted tubes (066 Y1) was reinspected in order to isolate the area with indications. Once this was performed, it was decided to cut the tube to make a visual inspection and to evaluate to what type of defect corresponds to the signals obtained. In the metallography it was confirm that it was a horseshoe type defect. When performing a dimensional control test of the found real defect, it was checked that the information obtained by eddy currents regarding the diminishing of the wall thickness diminishing was valid. At a last stage of the test, it was proceed to make an study and verification of the used parameters, probes, standards and finally determine which shall be the convenient modifications to minimize errors. (author)

  13. Assessment of RELAP5/MOD3.2 with condensation experiment in the presence of noncondensables in a vertical tube

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyun Sik; No, Hee Cheon [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1999-12-31

    The standard RELAP5/MOD3.2 code were assessed with the condensation experiment in the presence of noncondensable gas in a vertical tube of PCCS of CP-1300. There are two wall film condensation models, the default model and the alternative model, in RELAP5/MOD3.2. The experimental apparatus was modeled with the two models, and simulations were performed for several sub-tests to be compared with the experimental results. In overall sense the simulation results showed that the default model of RELAP5/MOD3.2 under-predicts the heat transfer coefficients, while the alternative model over-predicts them throughout the condensing tube. 10 refs., 6 figs. (Author)

  14. Assessment of RELAP5/MOD3.2 with condensation experiment in the presence of noncondensables in a vertical tube

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyun Sik; No, Hee Cheon [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1998-12-31

    The standard RELAP5/MOD3.2 code were assessed with the condensation experiment in the presence of noncondensable gas in a vertical tube of PCCS of CP-1300. There are two wall film condensation models, the default model and the alternative model, in RELAP5/MOD3.2. The experimental apparatus was modeled with the two models, and simulations were performed for several sub-tests to be compared with the experimental results. In overall sense the simulation results showed that the default model of RELAP5/MOD3.2 under-predicts the heat transfer coefficients, while the alternative model over-predicts them throughout the condensing tube. 10 refs., 6 figs. (Author)

  15. Augmentative effect of pulsatility on the wall shear stress in tube flow.

    Science.gov (United States)

    Nakata, M; Tatsumi, E; Tsukiya, T; Taenaka, Y; Nishimura, T; Nishinaka, T; Takano, H; Masuzawa, T; Ohba, K

    1999-08-01

    Wall shear stress (WSS) has been considered to play an important role in the physiological and metabolic functions of the vascular endothelial cells. We investigated the effects of the pulse rate and the maximum flow rate on the WSS to clarify the influence of pulsatility. Water was perfused in a 1/2 inch transparent straight cylinder with a nonpulsatile centrifugal pump and a pulsatile pneumatic ventricular assist device (VAD). In nonpulsatile flow (NF), the flow rate was changed 1 to 6 L/min by 1 L/min increments to obtain standard values of WSS at each flow rate. In pulsatile flow (PF), the pulse rate was controlled at 40, 60, and 80 bpm, and the maximum flow rate was varied from 3.3 to 12.0 L/min while the mean flow rate was kept at 3 L/min. The WSS was estimated from the velocity profile at measuring points using the laser illuminated fluorescence method. In NF, the WSS was 12.0 dyne/cm2 at 3 L/min and 33.0 dyne/cm2 at 6 L/min. In PF, the pulse rate change with the same mean, and the maximum flow rate did not affect WSS. On the other hand, the increase in the maximum flow rate at the constant mean flow rate of 3 L/min augmented the mean WSS from 13.1 to 32.9 dyne/cm2. We concluded that the maximum flow rate exerted a substantial augmentative effect on WSS, and the maximum flow rate was a dominant factor of pulsatility in this effect.

  16. Main results of assessing integrity of RNPP-3 steam generator heat exchange tubes in accident management

    International Nuclear Information System (INIS)

    Shugajlo, Al-j P.; Mustafin, M.A.; Shugajlo, Al-r P.; Ryzhov, D.I.; Zhabin, O.I.

    2017-01-01

    Tubes integrity evaluation under accident conditions considering drain of SG and current technical state of steam exchange tubes is an important question regarding SG long-term operation and improvement of accident management strategy.The main investigation results prepared for heat exchange surface of RNPP-3 steam generator are presented in this research aimed at assessing integrity of heat exchange tubes under accident conditions, which lead to full or partial drain of heat exchange surface, in particular during station blackout.

  17. The Apical Actin Fringe Contributes to Localized Cell Wall Deposition and Polarized Growth in the Lily Pollen Tube1[W][OPEN

    Science.gov (United States)

    Rounds, Caleb M.; Hepler, Peter K.; Winship, Lawrence J.

    2014-01-01

    In lily (Lilium formosanum) pollen tubes, pectin, a major component of the cell wall, is delivered through regulated exocytosis. The targeted transport and secretion of the pectin-containing vesicles may be controlled by the cortical actin fringe at the pollen tube apex. Here, we address the role of the actin fringe using three different inhibitors of growth: brefeldin A, latrunculin B, and potassium cyanide. Brefeldin A blocks membrane trafficking and inhibits exocytosis in pollen tubes; it also leads to the degradation of the actin fringe and the formation of an aggregate of filamentous actin at the base of the clear zone. Latrunculin B, which depolymerizes filamentous actin, markedly slows growth but allows focused pectin deposition to continue. Of note, the locus of deposition shifts frequently and correlates with changes in the direction of growth. Finally, potassium cyanide, an electron transport chain inhibitor, briefly stops growth while causing the actin fringe to completely disappear. Pectin deposition continues but lacks focus, instead being delivered in a wide arc across the pollen tube tip. These data support a model in which the actin fringe contributes to the focused secretion of pectin to the apical cell wall and, thus, to the polarized growth of the pollen tube. PMID:25037212

  18. Electromechanical properties of multi-walled carbon nano-tubes; Proprietes electromecaniques des nanotubes de carbone multiparois

    Energy Technology Data Exchange (ETDEWEB)

    Lefevre, R

    2005-12-15

    In this PhD thesis, we tackled theoretically and experimentally the problem of designing nano-electromechanical systems (NEMS) based on multi-walled carbon nano-tubes (MWCNTs). Furthermore, we applied our know-how to perform components like switches. We developed a theoretical model to describe the deflection of a suspended MWCNT stressed by an attractive electrostatic force. Our model highlights a scaling law linking up the electrostatic deflection, geometrical, electrical and physical parameters of MWCNTs based NEMS. This result constitutes a practical designing tool because it predicts their electromechanical behaviour on a 'large' range of operational parameters. At the same time, we developed several processes to fabricate nano-structures incorporating a suspended MWCNT electrostatically actuated. Among these different structures, the simplest was used to develop a method for probing electromechanical properties of MWCNTs. Our method is based on atomic force microscopy measurements on a doubly clamped suspended MWCNT electrostatically deflected by a drive voltage. These measurements show clearly for different MWCNTs (different diameter and length) the existence of such scaling law in agreement with the continuum model prediction. From these results, we extracted the Young's modulus of MWCNTs. For diameters smaller than 30 nm it is constant and its average value equals 400 GPa. Above, we observed a strong decrease that could be explained by the entry in a non-linear regime of deformation. Finally, we show the realization of an electromechanical switch based on a suspended MWCNT which presents good switching behaviour. (author)

  19. Nonlinear optical properties of polyaniline and poly (o-toluidine) composite thin films with multi walled carbon nano tubes

    Energy Technology Data Exchange (ETDEWEB)

    Nagaraja, K.K. [National University of Science and Technology “MISiS”, Leninskii pr. 4, Moscow 119049 (Russian Federation); Pramodini, S. [Department of Physics, School of Engineering and Technology, Jain University, Jakkasandra Post, Bengaluru 5621112, Karnataka (India); Poornesh, P., E-mail: poorneshp@gmail.com [Nonlinear Optics Research Laboratory, Department of Physics, Manipal Institute of Technology, Manipal University, Manipal 576 104, Karnataka (India); Telenkov, M.P. [National University of Science and Technology “MISiS”, Leninskii pr. 4, Moscow 119049 (Russian Federation); Kityk, I.V. [Electrical Engineering Department, Czestochowa University Technology, Czestochowa (Poland)

    2017-05-01

    We report the improved third-order nonlinear optical properties of polyaniline and poly (o-toluidine) with different doping concentrations of multi walled carbon nano tube (MWCNTs) composite thin films investigated using z-scan technique and continuous wave He–Ne laser at 633 nm wavelength was used as source of excitation. Thin films were prepared by spin coating technique on glass substrate. The structural properties of the composite films were analysed by X-ray diffraction studies and the characteristic peaks corresponding to MWCNTs and polymers have been observed. The surface morphology of the deposited films was analysed using scanning electron microscopy and it confirms that the polymer in the composites has been coated on the MWCNTs homogeneously. The z-scan results reveal that the films exhibit reverse saturable absorption and self-defocusing nonlinearity. The third-order nonlinear optical susceptibility χ{sup (3)} is found to be of the order of 10{sup −3} esu. Also, optical power limiting and clamping experiment was performed. The clamping values increases with increase in concentration and the lowest clamping observed for composite films are 1 mW and 0.7 mW.

  20. Electromechanical properties of multi-walled carbon nano-tubes; Proprietes electromecaniques des nanotubes de carbone multiparois

    Energy Technology Data Exchange (ETDEWEB)

    Lefevre, R.

    2005-12-15

    In this PhD thesis, we tackled theoretically and experimentally the problem of designing nano-electromechanical systems (NEMS) based on multi-walled carbon nano-tubes (MWCNTs). Furthermore, we applied our know-how to perform components like switches. We developed a theoretical model to describe the deflection of a suspended MWCNT stressed by an attractive electrostatic force. Our model highlights a scaling law linking up the electrostatic deflection, geometrical, electrical and physical parameters of MWCNTs based NEMS. This result constitutes a practical designing tool because it predicts their electromechanical behaviour on a 'large' range of operational parameters. At the same time, we developed several processes to fabricate nano-structures incorporating a suspended MWCNT electrostatically actuated. Among these different structures, the simplest was used to develop a method for probing electromechanical properties of MWCNTs. Our method is based on atomic force microscopy measurements on a doubly clamped suspended MWCNT electrostatically deflected by a drive voltage. These measurements show clearly for different MWCNTs (different diameter and length) the existence of such scaling law in agreement with the continuum model prediction. From these results, we extracted the Young's modulus of MWCNTs. For diameters smaller than 30 nm it is constant and its average value equals 400 GPa. Above, we observed a strong decrease that could be explained by the entry in a non-linear regime of deformation. Finally, we show the realization of an electromechanical switch based on a suspended MWCNT which presents good switching behaviour. (author)

  1. Mount Protects Thin-Walled Glass or Ceramic Tubes from Large Thermal and Vibration Loads

    Science.gov (United States)

    Amato, Michael; Schmidt, Stephen; Marsh. James; Dahya, Kevin

    2011-01-01

    The design allows for the low-stress mounting of fragile objects, like thin walled glass, by using particular ways of compensating, isolating, or releasing the coefficient of thermal expansion (CTE) differences between the mounted object and the mount itself. This mount profile is lower than true full kinematic mounting. Also, this approach enables accurate positioning of the component for electrical and optical interfaces. It avoids the higher and unpredictable stress issues that often result from potting the object. The mount has been built and tested to space-flight specifications, and has been used for fiber-optic, optical, and electrical interfaces for a spaceflight mission. This mount design is often metal and is slightly larger than the object to be mounted. The objects are optical or optical/electrical, and optical and/or electrical interfaces are required from the top and bottom. This requires the mount to be open at both ends, and for the object s position to be controlled. Thin inside inserts at the top and bottom contact the housing at defined lips, or edges, and hold the fragile object in the mount. The inserts can be customized to mimic the outer surface of the object, which further reduces stress. The inserts have the opposite CTE of the housing material, partially compensating for the CTE difference that causes thermal stress. A spring washer is inserted at one end to compensate for more CTE difference and to hold the object against the location edge of the mount for any optical position requirements. The spring also ensures that any fiber-optic or optic interface, which often requires some pressure to ensure a good interface, does not overstress the fragile object. The insert thickness, material, and spring washer size can be traded against each other to optimize the mount and stresses for various thermal and vibration load ranges and other mounting requirements. The alternate design uses two separate, unique features to reduce stress and hold the

  2. Flow instability research on steam generator with straight double-walled heat transfer tube for FBR. Pressure drop under high pressure condition

    International Nuclear Information System (INIS)

    Liu, Wei; Tamai, Hidesada; Yoshida, Hiroyuki; Takase, Kazuyuki; Hayafune, Hiroki; Futagami, Satoshi; Kisohara, Naoyuki

    2008-01-01

    For the Steam Generator (SG) with straight double-walled heat transfer tube that used in sodium cooled Faster Breeder Reactor, flow instability is one of the most important items need researching. As the first step of the research, thermal hydraulics experiments were performed under high pressure condition in JAEA with using a straight tube. Pressure drop, heat transfer coefficients and void fraction data were derived. This paper evaluates the pressure drop data with TRAC-BF1 code. The Pffan's correlation for single phase flow and the Martinelli-Nelson's two-phase flow multiplier are found can be well predicted the present pressure drop data under high pressure condition. (author)

  3. The aspects regarding plugging the defective tubes of the steam generator using plastic deformation of the plug wall by conventional or unconventional techniques

    International Nuclear Information System (INIS)

    Gyongyosi, Tiberiu

    2006-01-01

    After a brief introduction the advantages and disadvantages of two plugging methods of the defective tubes from steam generator by plastic deformation of the wall of the plug, deformation performed by mechanical rolling (conventional technique) and by electrohydraulic shock (unconventional technique), respectively, are showed. The paper gives the results of the experimental tests to install the plugs at the end of the tube having the same geometry with those of the steam generator, the performance reached in this stage and some conclusions in the end

  4. Blood compatibility assessment of graft copolymer (NR-g-DMAA) tubes

    International Nuclear Information System (INIS)

    Razzak, M.T.; Otsuhata, Kazushige; Tabata, Yoneho; Ohashi, Fumio; Takeuchi, Atsuki

    1992-01-01

    Graft copolymer (NR-g-DMAA) tubes have been prepared using simultaneous radiation induced grafting of N,N-dimethyl-acrylamide, (DMAA) onto natural rubber (NR) tubes. The blood compatibility of the NR-g-DMAA tubes was assessed with three methods, namely in vitro test, ex vivo once through test and ex vivo loops test. In the case of the in vitro test, a simple whole blood contacting procedure has been employed. The ex vivo once through test involves the exposing of NR-g-DMAA tubes with once through flow of fresh canine blood and then it was inspected for any evidence of clot. In the case of ex vivo loops test, the NR-g-DMAA tube was implanted at external jugular vein of a mongrel canine and the blood flow in the NR-g-DMAA tube was detected with an ultrasonic flow meter. It was found that the blood compatibility of NR-g-DMAA tubes is improved significantly with the increasing degree of grafting. All the NR-g-DMAA tubes having a degree of grafting of about 30 wt% or more exhibit good blood compatibility. It was found that the blood compatibility of the NR-g-DMAA tube is better than that of a medical grade silicon rubber (SiR) tube. (Author)

  5. Effects of Gas-Wall Partitioning in Teflon Tubing, Instrumentation and Other Materials on Time-Resolved Measurements of Gas-Phase Organic Compounds

    Science.gov (United States)

    Pagonis, D.; Deming, B.; Krechmer, J. E.; De Gouw, J. A.; Jimenez, J. L.; Ziemann, P. J.

    2017-12-01

    Recently it has been shown that gas-phase organic compounds partition to and from the walls of Teflon environmental chambers. This process is fast, reversible, and can be modeled as absorptive partitioning. Here these studies were extended to investigate gas-wall partitioning inside Teflon tubing by introducing step function changes in the concentration of compounds being sampled and measuring the delay in the response of a proton transfer reaction-mass spectrometer (PTR-MS). We find that these delays are significant for compounds with a saturation vapor concentration (c*) below 106 μg m-3, and that the Teflon tubing and the PTR-MS both contribute to the delays. Tubing delays range from minutes to hours under common sampling conditions and can be accurately predicted by a simple chromatography model across a range of tubing lengths and diameters, flow rates, compound functional groups, and c*. This method also allows one to determine the volatility-dependent response function of an instrument, which can be convolved with the output of the tubing model to correct for delays in instrument response time for these "sticky" compounds. This correction is expected to be of particular interest to researchers utilizing and developing chemical ionization mass spectrometry (CIMS) techniques, since many of the multifunctional organic compounds detected by CIMS show significant tubing and instrument delays. These results also enable better design of sampling systems, in particular when fast instrument response is needed, such as for rapid transients, aircraft, or eddy covariance measurements. Additional results presented here extend this method to quantify the relative sorptive capacities for other commonly used tubing materials, including PFA, FEP, PTFE, PEEK, glass, copper, stainless steel, and passivated steel.

  6. Probabilistic fracture mechanics applied for DHC assessment in the cool-down transients for CANDU pressure tubes

    Energy Technology Data Exchange (ETDEWEB)

    Radu, Vasile, E-mail: vasile.radu@nuclear.ro [Institute for Nuclear Research Pitesti, 1st Campului Street, 115400 Mioveni, Arges, P.O. Box 78, Mioveni (Romania); Roth, Maria [Institute for Nuclear Research Pitesti, 1st Campului Street, 115400 Mioveni, Arges, P.O. Box 78, Mioveni (Romania)

    2012-12-15

    For CANDU pressure tubes made from Zr-2.5%Nb alloy, the mechanism called delayed hydride cracking (DHC) is widely recognized as main mechanism responsible for crack initiation and propagation in the pipe wall. Generation of some blunt flaws at the inner pressure tube surface during refueling by fuel bundle bearing pad or by debris fretting, combined with hydrogen/deuterium up-take (20-40 ppm) from normal corrosion process with coolant, may lead to crack initiation and growth. The process is governed by hydrogen hysteresis of terminal solid solubility limits in Zirconium and the diffusion of hydrogen atoms in the stress gradient near to a stress spot (flaw). Creep and irradiation growth under normal operating conditions promote the specific mechanisms for Zirconium alloys, which result in circumferential expansion, accompanied by wall thinning and length increasing. These complicate damage mechanisms in the case of CANDU pressure tubes that are also are affected by irradiation environment in the reactor core. The structural integrity assessment of CANDU fuel channels is based on the technical requirements and methodology stated in the Canadian Standard N285.8. Usually it works with fracture mechanics principles in a deterministic manner. However, there are inherent uncertainties from the in-service inspection, which are associated with those from material properties determination; therefore a necessary conservatism in deterministic evaluation should be used. Probabilistic approach, based on fracture mechanics principle and appropriate limit state functions defined as fracture criteria, appears as a promising complementary way to evaluate structural integrity of CANDU pressure tubes. To perform this, one has to account for the uncertainties that are associated with the main parameters for pressure tube assessment, such as: flaws distribution and sizing, initial hydrogen concentration, fracture toughness, DHC rate and dimensional changes induced by long term

  7. Calculation of concrete shielding wall thickness for 450kVp X-ray tube with MCNP simulation and result comparison with half value layer method calculation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Heon; Lee, Eun Joong; Kim, Chan Kyu; Cho, Gyu Seong [Dept. of Nuclear and Quantum Engineering, KAIST, Daejeon (Korea, Republic of); Hur, Sam Suk [Sam Yong Inspection Engineering Co., Ltd., Seoul (Korea, Republic of)

    2016-11-15

    Radiation generating devices must be properly shielded for their safe application. Although institutes such as US National Bureau of Standards and National Council on Radiation Protection and Measurements (NCRP) have provided guidelines for shielding X-ray tube of various purposes, industry people tend to rely on 'Half Value Layer (HVL) method' which requires relatively simple calculation compared to the case of those guidelines. The method is based on the fact that the intensity, dose, and air kerma of narrow beam incident on shielding wall decreases by about half as the beam penetrates the HVL thickness of the wall. One can adjust shielding wall thickness to satisfy outside wall dose or air kerma requirements with this calculation. However, this may not always be the case because 1) The strict definition of HVL deals with only Intensity, 2) The situation is different when the beam is not 'narrow'; the beam quality inside the wall is distorted and related changes on outside wall dose or air kerma such as buildup effect occurs. Therefore, sometimes more careful research should be done in order to verify the effect of shielding specific radiation generating device. High energy X-ray tubes which is operated at the voltage above 400 kV that are used for 'heavy' nondestructive inspection is an example. People have less experience in running and shielding such device than in the case of widely-used low energy X-ray tubes operated at the voltage below 300 kV. In this study, Air Kerma value per week, outside concrete shielding wall of various thickness surrounding 450 kVp X-ray tube were calculated using MCNP simulation with the aid of Geometry Splitting method which is a famous Variance Reduction technique. The comparison between simulated result, HVL method result, and NCRP Report 147 safety goal 0.02 mGy wk-1 on Air Kerma for the place where the public are free to pass showed that concrete wall of thickness 80 cm is needed to achieve the

  8. Calculation of concrete shielding wall thickness for 450kVp X-ray tube with MCNP simulation and result comparison with half value layer method calculation

    International Nuclear Information System (INIS)

    Lee, Sang Heon; Lee, Eun Joong; Kim, Chan Kyu; Cho, Gyu Seong; Hur, Sam Suk

    2016-01-01

    Radiation generating devices must be properly shielded for their safe application. Although institutes such as US National Bureau of Standards and National Council on Radiation Protection and Measurements (NCRP) have provided guidelines for shielding X-ray tube of various purposes, industry people tend to rely on 'Half Value Layer (HVL) method' which requires relatively simple calculation compared to the case of those guidelines. The method is based on the fact that the intensity, dose, and air kerma of narrow beam incident on shielding wall decreases by about half as the beam penetrates the HVL thickness of the wall. One can adjust shielding wall thickness to satisfy outside wall dose or air kerma requirements with this calculation. However, this may not always be the case because 1) The strict definition of HVL deals with only Intensity, 2) The situation is different when the beam is not 'narrow'; the beam quality inside the wall is distorted and related changes on outside wall dose or air kerma such as buildup effect occurs. Therefore, sometimes more careful research should be done in order to verify the effect of shielding specific radiation generating device. High energy X-ray tubes which is operated at the voltage above 400 kV that are used for 'heavy' nondestructive inspection is an example. People have less experience in running and shielding such device than in the case of widely-used low energy X-ray tubes operated at the voltage below 300 kV. In this study, Air Kerma value per week, outside concrete shielding wall of various thickness surrounding 450 kVp X-ray tube were calculated using MCNP simulation with the aid of Geometry Splitting method which is a famous Variance Reduction technique. The comparison between simulated result, HVL method result, and NCRP Report 147 safety goal 0.02 mGy wk-1 on Air Kerma for the place where the public are free to pass showed that concrete wall of thickness 80 cm is needed to achieve the safety goal

  9. High-speed growth of TiO2 nanotube arrays with gradient pore diameter and ultrathin tube wall under high-field anodization

    Science.gov (United States)

    Yuan, Xiaoliang; Zheng, Maojun; Ma, Li; Shen, Wenzhong

    2010-10-01

    Highly ordered TiO2 nanotubular arrays have been prepared by two-step anodization under high field. The high anodizing current densities lead to a high-speed film growth (0.40-1.00 µm min - 1), which is nearly 16 times faster than traditional fabrication of TiO2 at low field. It was found that an annealing process of Ti foil is an effective approach to get a monodisperse and double-pass TiO2 nanotubular layer with a gradient pore diameter and ultrathin tube wall (nearly 10 nm). A higher anodic voltage and longer anodization time are beneficial to the formation of ultrathin tube walls. This approach is simple and cost-effective in fabricating high-quality ordered TiO2 nanotubular arrays for practical applications.

  10. High-speed growth of TiO{sub 2} nanotube arrays with gradient pore diameter and ultrathin tube wall under high-field anodization

    Energy Technology Data Exchange (ETDEWEB)

    Yuan Xiaoliang; Zheng Maojun; Shen Wenzhong [Key Laboratory of Artificial Structures and Quantum Control, Ministry of Education, Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Ma Li, E-mail: mjzheng@sjtu.edu.cn [School of Chemistry and Chemical Technology, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2010-10-08

    Highly ordered TiO{sub 2} nanotubular arrays have been prepared by two-step anodization under high field. The high anodizing current densities lead to a high-speed film growth (0.40-1.00 {mu}m min{sup -1}), which is nearly 16 times faster than traditional fabrication of TiO{sub 2} at low field. It was found that an annealing process of Ti foil is an effective approach to get a monodisperse and double-pass TiO{sub 2} nanotubular layer with a gradient pore diameter and ultrathin tube wall (nearly 10 nm). A higher anodic voltage and longer anodization time are beneficial to the formation of ultrathin tube walls. This approach is simple and cost-effective in fabricating high-quality ordered TiO{sub 2} nanotubular arrays for practical applications.

  11. A numerical study on the heat transfer in a swirl-tube heated/cooled on the half periphery of the tube wall

    International Nuclear Information System (INIS)

    Aoyama, Yoshiyuki; Kunugi, Tomoaki

    2002-01-01

    Convection heat transfer in a swirl tube was numerically analyzed so as to investigate a characteristic of heat removal when the cooling fluid flows within the swirl tube mounted in a solid structure represented as like a slab. Since the condition of heat inflow was treated as being transmitted only on the one-side surface of the structure, heat conduction through the structure was analyzed in linkage with the convection. Some results for the change in the coefficient of heat transmission along the tube axis are shown. The performance of heat removal was found to be strengthened due to the continuous renovation of thermal boundary layer close to the inside tube surface because the fluid flows in helical motion to shift the range alternate higher and lower temperature. (author)

  12. Effects of gas–wall partitioning in Teflon tubing and instrumentation on time-resolved measurements of gas-phase organic compounds

    Directory of Open Access Journals (Sweden)

    D. Pagonis

    2017-12-01

    Full Text Available Recent studies have demonstrated that organic compounds can partition from the gas phase to the walls in Teflon environmental chambers and that the process can be modeled as absorptive partitioning. Here these studies were extended to investigate gas–wall partitioning of organic compounds in Teflon tubing and inside a proton-transfer-reaction mass spectrometer (PTR-MS used to monitor compound concentrations. Rapid partitioning of C8–C14 2-ketones and C11–C16 1-alkenes was observed for compounds with saturation concentrations (c∗ in the range of 3 × 104 to 1 × 107 µg m−3, causing delays in instrument response to step-function changes in the concentration of compounds being measured. These delays vary proportionally with tubing length and diameter and inversely with flow rate and c∗. The gas–wall partitioning process that occurs in tubing is similar to what occurs in a gas chromatography column, and the measured delay times (analogous to retention times were accurately described using a linear chromatography model where the walls were treated as an equivalent absorbing mass that is consistent with values determined for Teflon environmental chambers. The effect of PTR-MS surfaces on delay times was also quantified and incorporated into the model. The model predicts delays of an hour or more for semivolatile compounds measured under commonly employed conditions. These results and the model can enable better quantitative design of sampling systems, in particular when fast response is needed, such as for rapid transients, aircraft, or eddy covariance measurements. They may also allow estimation of c∗ values for unidentified organic compounds detected by mass spectrometry and could be employed to introduce differences in time series of compounds for use with factor analysis methods. Best practices are suggested for sampling organic compounds through Teflon tubing.

  13. Effects of gas-wall partitioning in Teflon tubing and instrumentation on time-resolved measurements of gas-phase organic compounds

    Science.gov (United States)

    Pagonis, Demetrios; Krechmer, Jordan E.; de Gouw, Joost; Jimenez, Jose L.; Ziemann, Paul J.

    2017-12-01

    Recent studies have demonstrated that organic compounds can partition from the gas phase to the walls in Teflon environmental chambers and that the process can be modeled as absorptive partitioning. Here these studies were extended to investigate gas-wall partitioning of organic compounds in Teflon tubing and inside a proton-transfer-reaction mass spectrometer (PTR-MS) used to monitor compound concentrations. Rapid partitioning of C8-C14 2-ketones and C11-C16 1-alkenes was observed for compounds with saturation concentrations (c∗) in the range of 3 × 104 to 1 × 107 µg m-3, causing delays in instrument response to step-function changes in the concentration of compounds being measured. These delays vary proportionally with tubing length and diameter and inversely with flow rate and c∗. The gas-wall partitioning process that occurs in tubing is similar to what occurs in a gas chromatography column, and the measured delay times (analogous to retention times) were accurately described using a linear chromatography model where the walls were treated as an equivalent absorbing mass that is consistent with values determined for Teflon environmental chambers. The effect of PTR-MS surfaces on delay times was also quantified and incorporated into the model. The model predicts delays of an hour or more for semivolatile compounds measured under commonly employed conditions. These results and the model can enable better quantitative design of sampling systems, in particular when fast response is needed, such as for rapid transients, aircraft, or eddy covariance measurements. They may also allow estimation of c∗ values for unidentified organic compounds detected by mass spectrometry and could be employed to introduce differences in time series of compounds for use with factor analysis methods. Best practices are suggested for sampling organic compounds through Teflon tubing.

  14. Integrated straight - through automatic non-destructive examination and data acquisition system for thin-wall tubes

    International Nuclear Information System (INIS)

    Stoessel, A.; Boulanger, G.; Furlan, J.; Mogavero, R.

    1981-09-01

    This non-destructive testing unit inspects the cladding tubes for the SUPER-PHENIX fast neutron reactor. The quality level demanded for these tubes, as well as their number, required designing an installation that combined high performance with a great testing rate and complete automation. The testing is effected under immersion by means of six transducers, focused in line, working at 30 MHz. The tubes are numbered on an automatic rig; marking is by dark rings obtained by superficial electrolysis of the tube and regularly distributed on the abscissa; the quality of the tube is not affected by this. The advantage of this numbering system is that it enables the tubes to be fed to the test set in any order. An acquisition unit, constituted of a microprocessor, a semi-graphical printer and a double floppy disk unit, makes it possible to enter, edit and store the information for each tube [fr

  15. Influence of Mn contents in 0Cr18Ni10Ti thin wall stainless steel tube on TIG girth weld quality

    Science.gov (United States)

    Liu, Bo

    2017-03-01

    Three kinds of cold worked 0Cr18Ni10Ti thin wall stainless steel tubes with the manganese contents of 1.27%, 1.35% and 1.44% and the cold worked 0Cr18Ni10Ti stainless steel end plug with manganese content of 1.35% were used for TIG girth welding in the present investigation. The effect of different manganese contents in stainless steel tube on weld quality was studied. The results showed that under the same welding conditions, the metallographic performance of the girth weld for the thin wall stainless steel tube with the manganese element content 1.44% welded with end plug was the best. Under the appropriate welding conditions, the quality of the girth weld increased with the increase of the manganese content till 1.44%. It was found that in the case of the Mn content of 1.44%, and under the proper welding condition the welding defects, such as welding cracks were effectively avoided, and the qualified weld penetration can be obtained.. It is concluded that the appropriate increase of the manganese content can significantly improve the TIG girth weld quality of the cold worked 0Cr18Ni10Ti stainless steel tube.

  16. Residual life assessment of thick wall boiler parts

    International Nuclear Information System (INIS)

    Mehdizadeh, M.; Rayatpour, M.

    2004-01-01

    Thick wall components of boiler, such as headers, main steam lines and hot reheat lines, operate at high temperature and stress condition. This condition makes various failure mechanisms to activate during service exposure that gradually deteriorate the microstructure of components. Consequently, knowing about metallurgical condition and remaining life sensitive components particularly in power plants with at least 100,000 her life time is of considerable importance. In this regard, to eliminate unexpected interruptions and reduce the repairing costs, life assessment technology is being used. Various life assessment methods have been developed for power plants components and entered industrial fields. In the present work, remaining life of drums, headers and main steam lines of a power plant were evaluated, using microstructural, hardness changes and dimensional checking methods with non destructive tests. The results show that, the components have appropriate condition according to their service life. Further more, it was revealed that hardness evaluation technique is not a reliable evaluation criteria and various methods should be used for accurate life assessment

  17. Assessment of need for transport tubes when continuously monitoring for radioactive aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Whicker, J.J.; Rodgers, J.C.; Lopez, R.C.

    1999-09-01

    Aerosol transport tubes are often used to draw aerosol from desirable sampling locations to nearby air sampling equipment that cannot be placed at that location. In many plutonium laboratories at Los Alamos National Laboratory, aerosol transport tubes are used to transport aerosol from the front of room ventilation exhaust registers to continuous air monitors (CAMs) that are mounted on nearby walls. Despite designs to minimize particle loss in tubes, aerosol transport model predictions suggest losses occur lowering the sensitivity of CAMs to accidentally released plutonium aerosol. The goal of this study was to test the hypotheses that the reliability, speed, and sensitivity of aerosol detection would be equal whether the sample was extracted from the front of the exhaust register or from the wall location of CAMs. Polydisperse oil aerosols were released from multiple locations in two plutonium laboratories to simulate plutonium aerosol releases. Networked laser particle counters (LPCs) were positioned to simultaneously measure time-resolved aerosol concentrations at each exhaust register and at each wall-mounted CAM location.

  18. Application of elastic wave dispersion relations to estimate thermal properties of nanoscale wires and tubes of varying wall thickness and diameter

    International Nuclear Information System (INIS)

    Bifano, Michael F P; Kaul, Pankaj B; Prakash, Vikas

    2010-01-01

    This paper reports dependency of specific heat and ballistic thermal conductance on cross-sectional geometry (tube versus rod) and size (i.e., diameter and wall thickness), in free-standing isotropic non-metallic crystalline nanostructures. The analysis is performed using dispersion relations found by numerically solving the Pochhammer-Chree frequency equation for a tube. Estimates for the allowable phonon dispersion relations within the crystal lattice are obtained by modifying the elastic acoustic dispersion relations so as to account for the discrete nature of the material's crystal lattice. These phonon dispersion relations are then used to evaluate the specific heat and ballistic thermal conductance in the nanostructures as a function of the nanostructure geometry and size. Two major results are revealed in the analysis: increasing the outer diameter of a nanotube while keeping the ratio of the inner to outer tube radius (γ) fixed increases the total number of available phonon modes capable of thermal population. Secondly, decreasing the wall thickness of a nanotube (i.e., increasing γ) while keeping its outer diameter fixed, results in a drastic decrease in the available phonon mode density and a reduction in the frequency of the longitudinal and flexural acoustic phonon modes in the nanostructure. The dependency of the nanostructure's specific heat on temperature indicates 1D, 2D, and 3D geometric phonon confinement regimes. Transition temperatures for each phonon confinement regime are shown to depend on both the nanostructure's wall thickness and outer radius. Compared to nanowires (γ = 0), the frequency reduction of acoustic phonon modes in thinner walled nanotubes (γ = 0.96) is shown to elevate the ballistic thermal conductance of the thin-walled nanotube between 0.2 and 150 K. At 20 K, the ballistic thermal conductance of the thin-walled nanotube (γ = 0.96) becomes 300% greater than that of a solid nanowire. For temperatures above 150 K, the trend

  19. Probabilistic integrity assessment of pressure tubes in an operating pressurized heavy water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Young-Jin; Park, Heung-Bae [KEPCO E and C, 188 Gumi-dong, Bundang-gu, Seongnam-si, Gyeonggi-do 463-870 (Korea, Republic of); Lee, Jung-Min; Kim, Young-Jin [School of Mechanical Engineering, Sungkyunkwan University, 300 Chunchun-dong, Jangan-gu, Suwon-si, Gyeonggi-do 440-746 (Korea, Republic of); Ko, Han-Ok [Korea Institute of Nuclear Safety, 34 Gwahak-ro, Yuseong-gu, Daejeon-si 305-338 (Korea, Republic of); Chang, Yoon-Suk, E-mail: yschang@khu.ac.kr [Department of Nuclear Engineering, Kyung Hee University, 1 Seocheon-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-701 (Korea, Republic of)

    2012-02-15

    Even though pressure tubes are major components of a pressurized heavy water reactor (PHWR), only small proportions of pressure tubes are sampled for inspection due to limited inspection time and costs. Since the inspection scope and integrity evaluation have been treated by using a deterministic approach in general, a set of conservative data was used instead of all known information related to in-service degradation mechanisms because of inherent uncertainties in the examination. Recently, in order that pressure tube degradations identified in a sample of inspected pressure tubes are taken into account to address the balance of the uninspected ones in the reactor core, a probabilistic approach has been introduced. In the present paper, probabilistic integrity assessments of PHWR pressure tubes were carried out based on accumulated operating experiences and enhanced technology. Parametric analyses on key variables were conducted, which were periodically measured by in-service inspection program, such as deuterium uptake rate, dimensional change rate of pressure tube and flaw size distribution. Subsequently, a methodology to decide optimum statistical distribution by using a robust method adopting a genetic algorithm was proposed and applied to the most influential variable to verify the reliability of the proposed method. Finally, pros and cons of the alternative distributions comparing with corresponding ones derived from the traditional method as well as technical findings from the statistical assessment were discussed to show applicability to the probabilistic assessment of pressure tubes.

  20. Experimental Assessment of Mechanical Night Ventilation on Inner Wall Surfaces

    DEFF Research Database (Denmark)

    Ji, Wenhui; Heiselberg, Per Kvols; Wang, Houhua

    2016-01-01

    The cooling potential of night ventilation largely depends on the heat exchange at the internal room surfaces. During night time, increased heat transfer on a vertical wall is expected due to cool supply air that flows along the internal wall surface from the top of the wall. This paper presents ...... an experimental study of the cooling of wall surfaces in a test room by mechanical night-time ventilation. Significant improvement of indoor thermal environment is presented resulting from the enhanced internal convection heat transfer....

  1. Maximum utilization of primary reformer catalyst tubes careful assessment of remaining life-An experience at an ammonia plant

    International Nuclear Information System (INIS)

    Malik, M.A.

    2005-01-01

    Condition evaluation and residual life assessment of Reformer Catalyst Tubes has always been a point of concern for Ammonia and Methanol Plant operators. Failure of catalyst tubes results in total plant shutdown and consequent production loss. On the other hand, replacement of these tubes entails major cost impact on the company's budget, being a capital expenditure. A careful Residual Life Assessment of the tubes is therefore of utmost importance for maximum utilization of these tubes without jeopardizing plant operational reliability. This paper presents an experience of extracting maximum service life from the catalyst tubes of Primary Reformer of an Ammonia Plant. Fauji Fertilizer Company (FFC) has been operating the plant since 1982, having a designed capacity of 1100 MTPD. Its Primary Reformer has 288 catalyst tubes of IN-519 material (24Cr-24Ni-Nb). The design temperature and pressures are 925 degree C and 38kg/Cm respectively. Thanks to the optimum operating conditions, regular inspections and careful assessment of the residual life, the tubes have achieved more than double of the designed life and are still operating reliably. To evaluate the tube's health, Ultrasonic Inspection (UT) was carried out in 1987 and 1994 using attenuation technique. The tubes with maximum attenuation were marked for further evaluation. Accelerated Creep Rupture Test was carried out on sample tubes periodically (1996, 2001 and 2004). Tubes were selected on the basis of UT results, TMT (Tube Metal Temperature) monitoring and Inspection findings. Based on the combined results of DT, NDT, equipment history and foreseen operational parameters, the life of these tubes was carefully assessed periodically. The tubes have been in service for more than 23 years (design life: 11 years) and a further life of 04 years has been predicted as per last assessment.The experience of successful health evaluation and residual life assessment has saved substantial cost involved in tubes replacement

  2. Collapse of thin wall tubes small initial ovality; Colapso de tubos de pared delgada con pequena ovalidad inicial

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, A

    1977-07-01

    In this work a simple model of creep collapse of tubes based on the bending theory of curved beams, is developed. The model is compared with more complex models. The main result of this work is the definition of a new model of creep collapse of tubes with a minimum of limitative hypothesis. (Author) 6 refs.

  3. Efficiency analysis and assessment of interlocking PVC sheet piling walls

    International Nuclear Information System (INIS)

    Emam, A.A.

    2005-01-01

    The use of PVC sheet piling in marine environments offers a number of unique advantages that include weight saving, corrosion resistance and environmentally safe material. In this study, one of the widely used classical methods as well as a finite element analysis are used to analyze such sheet piling walls. The analysis focuses on the effect of some important parameters on the wall global behavior, bending moments, stresses and deflections. The parameters include wall cross-section, wall height, embedment depth, number and spacing of anchor rods, and type of soil and loading conditions. Furthermore, the effect of the shape of the wall cross-section and the location of the interlocking joints has been studied by using plane frame and arch-like models. Results indicate that the finite element modeling is an effective tool for numerical approximation of soil-structure interaction problems. The required theoretical embedment depth is nearly 30 % of the clear wall height. Also, the modulus of subgrade reaction has a minor effect on both cantilever wall and one anchor sheet-pile wall. Finally, lateral (horizontal) action shows that deep sections tend to behave like an arch under radial loading which might increase normal stresses at some critical sections

  4. Tracheal palpation to assess endotracheal tube depth: an exploratory study.

    Science.gov (United States)

    McKay, William P; Klonarakis, Jim; Pelivanov, Vladko; O'Brien, Jennifer M; Plewes, Chris

    2014-03-01

    Correct placement of the endotracheal tube (ETT) occurs when the distal tip is in mid-trachea. This study compares two techniques used to place the ETT at the correct depth during intubation: tracheal palpation vs placement at a fixed depth at the patient's teeth. With approval of the Research Ethics Board, we recruited American Society of Anesthesiologists physical status I-II patients scheduled for elective surgery with tracheal intubation. Clinicians performing the tracheal intubations were asked to "advance the tube slowly once the tip is through the cords". An investigator palpated the patient's trachea with three fingers spread over the trachea from the larynx to the sternal notch. When the ETT tip was felt in the sternal notch, the ETT was immobilized and its position was determined by fibreoptic bronchoscopy. The position of the ETT tip was compared with our hospital standard, which is a depth at the incisors or gums of 23 cm for men and 21 cm for women. The primary outcome was the incidence of correct placement. Correct placement of the ETT was defined as a tip > 2.5 cm from the carina and > 3.5 cm below the vocal cords. Movement of the ETT tip was readily palpable in 77 of 92 patients studied, and bronchoscopy was performed in 85 patients. Placement by tracheal palpation resulted in more correct placements (71 [77%]; 95% confidence interval [CI] 74 to 81) than hospital standard depth at the incisors or gums (57 [61%]; 95% CI 58 to 66) (P = 0.037). The mean (SD) placement of the ETT tip in palpable subjects was 4.1 (1.7) cm above the carina, 1.9 cm (1.5-2.3 cm) below the ideal mid-tracheal position. Tracheal palpation requires no special equipment, takes only a few seconds to perform, and may improve ETT placement at the correct depth. Further studies are warranted.

  5. 75 FR 33779 - Light-Walled Rectangular Pipe and Tube from Turkey; Notice of Preliminary Results of Antidumping...

    Science.gov (United States)

    2010-06-15

    ..., Inc. and Searing Industries, Inc. are petitioners in this case. The review covers exports of the..., Atlas Tube, Inc. and Searing Industries, Inc. (``Petitioners'') made an entry of appearance in this...

  6. AC dielectrophoresis alignment of single-walled carbon nano tubes (SWNTS) and palladium nano wires for hydrogen gas sensor

    International Nuclear Information System (INIS)

    Nur Ubaidah Saidin; Nur Ubaidah Saidin; Ying, K.K.; KKhuan, N.I.; Mohammad Hafizuddin Jumali

    2013-01-01

    Full-text: Using AC electric field, nano wires or nano tubes can be aligned, chained or accelerated in a direction parallel to the applied field, oriented or concentrated onto designated locations as well as dispersed in controlled manner under high efficiencies. In this work, systematic study on the alignment of nano wires/ nano tubes across the 3 μm-gaps between pairs of micro fabricated gold electrodes was carried out using AC dielectrophoresis technique. Densities and alignment of the nano wires/ nano tubes across the gaps of the electrodes were controlled by the applied AC field strengths and frequencies on the electrodes. Good alignments of SWNTs and Pd nano wires were achieved at an applied frequency of 5 MHz and a field strength as high as 25 V pp for Pd nano wires compared to only 2 V pp for SWNTs. The aligned nano wires/ nano tubes will be functioned as sensor elements for hydrogen gas sensing. (author)

  7. Assessment of Soil Arching Factor for Retaining Wall Pile Foundations

    Science.gov (United States)

    2017-03-31

    Despite the prevalence of the soldier piles retaining wall systems as temporary and even permanent shoring systems along state highways, relatively little is known on the effect of the foreslope bench width and the slope inclination on the arching ca...

  8. Mechanical performance and sustainability assessment of reinforced soil walls

    OpenAIRE

    Puig Damians, Ivan

    2016-01-01

    Soil reinforced retaining wall structures are materiallymore efficientthan competing construction solutions such as gravity and cantilever walls. Nevertheless, the behaviour and interactions between the com ponent materials are com plex and not fully understood. Current design methods are typically limited to simple cases with respect to material properties, geometry, and boundary conditions. Advanced numerical models using finite element and/or finite difference methods offer the possibility...

  9. Full Scale Measurements and CFD Investigations of a Wall Radiant Cooling System Based on Plastic Capillary Tubes in Thin Concrete Walls

    DEFF Research Database (Denmark)

    Mikeska, Tomás; Fan, Jianhua; Svendsen, Svend

    2017-01-01

    Densely occupied spaces such as classrooms can very often have problems with overheating. It can be difficult to cool such spaces by means of a ventilation system without creating draughts and causing discomfort for occupants. The use of a wall radiant cooling system is a suitable option for spaces...

  10. Application of Response Surface Methodology for Optimization of Urea Grafted Multi walled Carbon Nano tubes in Enhancing Nitrogen Use Efficiency and Nitrogen Uptake by Paddy Plants

    International Nuclear Information System (INIS)

    Yatim, N. M.; Shaaban, A.; Dimin, M. F.; Yusof, F.; Abo Razak, J.

    2016-01-01

    Efficient use of urea fertilizer (UF) as important nitrogen (N) source in the world’s rice production has been a concern. Carbon-based materials developed to improve UF performance still represent a great challenge to be formulated for plant nutrition. Advanced N nano carrier is developed based on functionalized multi wall carbon nano tubes (f-MWCNTs) grafted with UF to produce urea-multi wall carbon nano tubes (UF-MWCNTs) for enhancing the nitrogen uptake (NU) and use efficiency (NUE). The grafted N can be absorbed and utilized by rice efficiently to overcome the N loss from soil-plant systems. The individual and interaction effect between the specified factors of f-MWCNTs amount (0.10-0.60 wt%) and functionalization reflux time (12-24 hrs) with the corresponding responses (NUE, NU) were structured via the Response Surface Methodology (RSM) based on five-level CCD. The UF-MWCNTs with optimized 0.5 wt% f-MWCNTs treated at 21 hrs reflux time achieve tremendous NUE up to 96% and NU at 1180 mg/pot. Significant model terms (Þ value < 0.05) for NUE and NU responses were confirmed by the ANOVA. Homogeneous dispersion of UF-MWCNTs was observed via FESEM and TEM. The chemical changes were monitored by FT-IR and Raman spectroscopy. Hence, this UF-MWCNTs’ approach provides a promising strategy in enhancing plant nutrition for rice.

  11. Influence of a boatlanding and j-tubes on wave loads and wall thickness of the monopile support structure design

    NARCIS (Netherlands)

    Segeren, M.L.A.

    2011-01-01

    Support structures for offshore wind turbines play a significant part in the cost of offshore wind energy. With current access systems a conventional boat landing is not necessary. Secondary steel, such as a boat landing and J-tube, influences wave loads. A way of taking the secondary steel items

  12. Sealing device and method for sealing fractures or leaks in wall or formation surrounding tube-shaped channel

    DEFF Research Database (Denmark)

    2014-01-01

    The sealing device (1) includes an elongated body (5) adapted to be introduced into a tube-shaped channel (2) and including a sealing fluid placement section (6) arranged between a first and a second annular flow barrier (7, 8). The elongated body further includes a sealing fluid activation secti...

  13. Intraoperative CT in the assessment of posterior wall acetabular fracture stability.

    Science.gov (United States)

    Cunningham, Brian; Jackson, Kelly; Ortega, Gil

    2014-04-01

    Posterior wall acetabular fractures that involve 10% to 40% of the posterior wall may or may not require an open reduction and internal fixation. Dynamic stress examination of the acetabular fracture under fluoroscopy has been used as an intraoperative method to assess joint stability. The aim of this study was to demonstrate the value of intraoperative ISO computed tomography (CT) examination using the Siemens ISO-C imaging system (Siemens Corp, Malvern, Pennsylvania) in the assessment of posterior wall acetabular fracture stability during stress examination under anesthesia. In 5 posterior wall acetabular fractures, standard fluoroscopic images (including anteroposterior pelvis and Judet radiographs) with dynamic stress examinations were compared with the ISO-C CT imaging system to assess posterior wall fracture stability during stress examination. After review of standard intraoperative fluoroscopic images under dynamic stress examination, all 5 cases appeared to demonstrate posterior wall stability; however, when the intraoperative images from the ISO-C CT imaging system demonstrated that 1 case showed fracture instability of the posterior wall segment during stress examination, open reduction and internal fixation was performed. The use of intraoperative ISO CT imaging has shown an initial improvement in the surgeon's ability to assess the intraoperative stability of posterior wall acetabular fractures during stress examination when compared with standard fluoroscopic images. Copyright 2014, SLACK Incorporated.

  14. Safety assessment of pipes with multiple local wall thinning defects under pressure and bending moment

    International Nuclear Information System (INIS)

    Peng Jian; Zhou Changyu; Xue Jilin; Dai Qiao; He Xiaohua

    2011-01-01

    The safety assessment of pipes with local wall thinning defects is highly important in engineering. Most attention has been paid on the safety assessment of pipe with single local wall thinning defect, while the studies about multiple local wall thinning defects are not nearly enough. However, the interaction of multiple local wall thinning defects in some conditions is great, and may have a great impact on the safety assessment. In the present standard API 579/ASME FFS, the safety assessment of pipes with multiple local wall thinning defects is given, while as well as the influence of load condition, the influences of arrangement and relative depth of defects are ignored, which may influence the safety assessment considerably. In this paper, the influence of the interaction between multiple local wall thinning defects on the remaining strength of pipes at different arrangements and depths of defects under different load conditions (pressure, tension-bending moment and compression-bending moment) are studied. A quantified index is defined to describe the interaction between defects quantitatively. For different arrangements and relative depths of defects, based on a limit value 0.05 of the quantified index of the interaction between defects, a relatively systematic safety assessment of pipes with multiple local wall thinning defects under different load conditions has been proposed.

  15. Assessment of microstructure and tensile behavior of continuous drive friction welded titanium tubes

    International Nuclear Information System (INIS)

    Palanivel, R.; Dinaharan, I.; Laubscher, R.F.

    2017-01-01

    Friction welding process has been applied to join Grade 2 titanium alloy tubes of outer diameter 60 mm and wall thickness 3.9 mm. In this research work, five different friction times (24, 28, 32, 36 and 40 s) were used to evaluate the ultimate tensile strength (UTS) and microstructure of welded tubes. Recording of the process parameters during welding was done. Optical microscopy, electron back scattered diffraction and transmission electron microscopy were used to study the microstructure. The results showed that the friction time had a significant influence on the microstructure and UTS. The rate of deformation increased with friction time and refined the grains in the weld zone. Coarse grain structure was observed from the center of the weld zone towards the flash. Identical grain structure was observed in the heat affected zone (HAZ) and the parent metal. It was found that a maximum joint efficiency of 98.3% was achieved at a friction time of 32 s.The details of microhardness, failure location and fracture surface of the welded tubes were reported.

  16. Assessment of microstructure and tensile behavior of continuous drive friction welded titanium tubes

    Energy Technology Data Exchange (ETDEWEB)

    Palanivel, R., E-mail: rpalanivelme@gmail.com; Dinaharan, I., E-mail: dinaweld2009@gmail.com; Laubscher, R.F., E-mail: rflaubscher@uj.ac.za

    2017-02-27

    Friction welding process has been applied to join Grade 2 titanium alloy tubes of outer diameter 60 mm and wall thickness 3.9 mm. In this research work, five different friction times (24, 28, 32, 36 and 40 s) were used to evaluate the ultimate tensile strength (UTS) and microstructure of welded tubes. Recording of the process parameters during welding was done. Optical microscopy, electron back scattered diffraction and transmission electron microscopy were used to study the microstructure. The results showed that the friction time had a significant influence on the microstructure and UTS. The rate of deformation increased with friction time and refined the grains in the weld zone. Coarse grain structure was observed from the center of the weld zone towards the flash. Identical grain structure was observed in the heat affected zone (HAZ) and the parent metal. It was found that a maximum joint efficiency of 98.3% was achieved at a friction time of 32 s.The details of microhardness, failure location and fracture surface of the welded tubes were reported.

  17. Assessment of Real Heat Transfer Coefficients through Shell and Tube and Plate Heat Exchangers

    Directory of Open Access Journals (Sweden)

    Dan CONSTANTINESCU

    2011-07-01

    Full Text Available The purpose of this paper is to present a procedure used in the assessment of the real heat transfer characteristic of shell and tube and plate heat exchangers. The theoretical fundamentals of the procedure are introduced as well as the measured data collection and processing. The theoretical analysis is focused on the adoption of criterial equations which, subjected to certain verification criteria presented in the paper, provide the most credible value of the convection heat transfer coefficients inside the circular and flat tubes. In the end two case studies are presented, one concerning a shell and tube heat exchanger operational at INCERC Thermal Substation and the other concerning a plate heat exchanger tested on the Laboratory Stand of the Department of Building Services and Efficient Use of Energy in Buildings of INCERC Bucharest.

  18. Assessment of turbulent flow effects on the vessel wall using four-dimensional flow MRI.

    Science.gov (United States)

    Ziegler, Magnus; Lantz, Jonas; Ebbers, Tino; Dyverfeldt, Petter

    2017-06-01

    To explore the use of MR-estimated turbulence quantities for the assessment of turbulent flow effects on the vessel wall. Numerical velocity data for two patient-derived models was obtained using computational fluid dynamics (CFD) for two physiological flow rates. The four-dimensional (4D) Flow MRI measurements were simulated at three different spatial resolutions and used to investigate the estimation of turbulent wall shear stress (tWSS) using the intravoxel standard deviation (IVSD) of velocity and turbulent kinetic energy (TKE) estimated near the vessel wall. Accurate estimation of tWSS using the IVSD is limited by the spatial resolution achievable with 4D Flow MRI. TKE, estimated near the wall, has a strong linear relationship to the tWSS (mean R 2  = 0.84). Near-wall TKE estimates from MR simulations have good agreement to CFD-derived ground truth (mean R 2  = 0.90). Maps of near-wall TKE have strong visual correspondence to tWSS. Near-wall estimation of TKE permits assessment of relative maps of tWSS, but direct estimation of tWSS is challenging due to limitations in spatial resolution. Assessment of tWSS and near-wall TKE may open new avenues for analysis of different pathologies. Magn Reson Med 77:2310-2319, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  19. Power spectral estimation of high-harmonics in echoes of wall resonances to improve resolution in non-invasive measurements of wall mechanical properties in rubber tube and ex-vivo artery.

    Science.gov (United States)

    Bazan, I; Ramos, A; Balay, G; Negreira, C

    2018-07-01

    The aim of this work is to develop a new type of ultrasonic analysis of the mechanical properties of an arterial wall with improved resolution, and to confirm its feasibility under laboratory conditions. it is expected that this would facilitate a non-invasive path for accurate predictive diagnosis that enables an early detection & therapy of vascular pathologies. In particular, the objective is to detect and quantify the small elasticity changes (in Young's modulus E) of arterial walls, which precede pathology. A submicron axial resolution is required for this analysis, as the periodic widening of the wall (under oscillatory arterial pressure) varies between ±10 and 20 μm. This high resolution represents less than 1% of the parietal thickness (e.g., harmonics of the wall internal resonance f 0 . This was attained via the implementation of an autoregressive parametric algorithm that accurately detects parietal echo-dynamics during a heartbeat. Thus, it was possible to measure the punctual elasticity of the wall, with a higher resolution (> an order of magnitude) compared to conventional approaches. The resolution of a typical ultrasonic image is limited to several hundred microns, and thus, such small changes are undetected. The proposed procedure provides a non-invasive and direct measure of elasticity by doing an estimation of changes in the Nf 0 harmonics and wall thickness with a resolution of 0.1%, for first time. The results obtained by using the classic temporal cross-correlation method (TCC) were compared to those obtained with the new procedure. The latter allowed the evaluation of alterations in the elastic properties of arterial walls that are 30 times smaller than those being detectable with TCC; in fact, the depth resolution of the TCC approach is limited to ≈20 μm for typical SNRs. These values were calculated based on echoes obtained using a reference pattern (rubber tube). The application of the proposed procedure was also confirmed via

  20. A quality assessment of cardiac auscultation material on YouTube.

    Science.gov (United States)

    Camm, Christian F; Sunderland, Nicholas; Camm, A John

    2013-02-01

    YouTube is a highly utilized Web site that contains a large amount of medical educational material. Although some studies have assessed the education material contained on the Web site, little analysis of cardiology content has been made. This study aimed to assess the quality of videos relating to heart sounds and murmurs contained on YouTube. We hypothesized that the quality of video files purporting to provide education on heart auscultation would be highly variable. Videos were searched for using the terms "heart sounds," "heart murmur," and "heart auscultation." A built-in educational filter was employed, and manual rejection of non-English language and nonrelated videos was undertaken. Remaining videos were analyzed for content, and suitable videos were scored using a purpose-built tool. YouTube search located 3350 videos in total, and of these, 22 were considered suitable for scoring. The average score was 4.07 out of 7 (standard deviation, 1.35). Six videos scored 5.5 or greater and 5 videos scoring 2.5 or less. There was no correlation between video score and YouTube indices of preference (hits, likes, dislikes, or search page). The quality of videos found in this study was highly variable. YouTube indications of preference were of no value in determining the value of video content. Therefore, teaching institutions or professional societies should endeavor to identify and highlight good online teaching resources. YouTube contains many videos relating to cardiac auscultation, but very few are valuable education resources. © 2012 Wiley Periodicals, Inc.

  1. Safety assessment of the potential for foreign object - caused fretting - wear damages on PWR steam generator U-tubes

    International Nuclear Information System (INIS)

    Jo, Jong Chull; Jhung, Myung Jo; Kim, Woong Sik; Kim, Hho Jung

    2003-01-01

    This study investigates the safety assessment of the potential for fretting-wear damages on Steam Generator (SG) U-tubes caused by foreign object in operating nuclear power plants. The operating SG shell-side flow field conditions are obtained from three-dimensional SG flow calculation using the ATHOS3 code. Modal analyses are performed for the finite element modelings of U-tubes to get the natural frequency, corresponding mode shape and participation factor. The wear rate of U-tube caused by foreign object is calculated using the Archard formula and the remaining life of the tube is predicted. Also, discussed in this study are the effects of flow velocity, internal pressure, tube-to-foreign object contact angle, and vibration of the tube on the remaining life of the tube

  2. Chamber wall response to target implosion in inertial fusion reactors: new and critical assessments

    International Nuclear Information System (INIS)

    Hassanein, A.; Morozov, V.

    2002-01-01

    The chamber walls in inertial fusion energy (IFE) reactors are exposed to harsh conditions following each target implosion. Key issues of the cyclic IFE operation include intense photon and ion deposition, wall thermal and hydrodynamic evolution, wall erosion and fatigue lifetime, and chamber clearing and evacuation to ensure desirable conditions prior to next target implosion. Several methods for wall protection have been proposed in the past, each having its own advantages and disadvantages. These methods include use of solid bare walls, gas-filled cavities, and liquid walls/jets. Detailed models have been developed for reflected laser light, emitted photons, and target debris deposition and interaction with chamber components and have been implemented in the comprehensive HEIGHTS software package. The focus of this study is to critically assess the reliability and the dynamic response of chamber walls in IFE systems. Of particular concern is the effect on wall erosion lifetime due to various erosion mechanisms, such as vaporization, chemical and physical sputtering, melt/liquid splashing and explosive erosion, and fragmentation of liquid walls

  3. Chamber wall response to target implosion in inertial fusion reactors : new and critical assessments

    International Nuclear Information System (INIS)

    Hassanein, A.; Morozov, V.

    2002-01-01

    The chamber walls in inertial fusion energy (IFE) reactors are exposed to harsh conditions following each target implosion. Key issues of the cyclic IFE operation include intense photon and ion deposition, wall thermal and hydrodynamic evolution, wall erosion and fatigue lifetime, and chamber clearing and evacuation to ensure desirable conditions prior to target implosion. Several methods for wall protection have been proposed in the past, each having its own advantages and disadvantages. These methods include use of solid bare walls, gas-filled cavities, and liquid walls/jets. Detailed models have been developed for reflected laser light, emitted photons, and target debris deposition and interaction with chamber components and have been implemented in the comprehensive HEIGHTS software package. The hydrodynamic response of gas filled cavities and photon radiation transport of the deposited energy has been calculated by means of new and advanced numerical techniques. Fragmentation models of liquid jets as a result of the deposited energy have also been developed, and the impact on chamber clearing dynamics has been evaluated. Th focus of this study is to critically assess the reliability and the dynamic response of chamber walls in various proposed protection methods for IFE systems. Of particular concern is the effect on wall erosion lifetime of various erosion mechanisms, such as vaporization, chemical and physical sputtering, melt/liquid splashing and explosive erosion, and fragmentation of liquid walls

  4. Structural integrity assessments of steam generator tubes using the FAD methodology

    Energy Technology Data Exchange (ETDEWEB)

    Bergant, Marcos A., E-mail: marcos.bergant@cab.cnea.gov.ar [Gerencia CAREM, Centro Atómico Bariloche (CNEA), Av. Bustillo 9500, San Carlos de Bariloche 8400 (Argentina); Yawny, Alejandro A., E-mail: yawny@cab.cnea.gov.ar [División Física de Metales, Centro Atómico Bariloche (CNEA)/CONICET, Av. Bustillo 9500, San Carlos de Bariloche 8400 (Argentina); Perez Ipiña, Juan E., E-mail: juan.perezipina@fain.uncoma.edu.ar [Grupo Mecánica de Fractura, Universidad Nacional del Comahue/CONICET, Buenos Aires 1400, Neuquén 8300 (Argentina)

    2015-12-15

    Highlights: • The Failure Assessment Diagram (FAD) is used to assess cracked steam generator tubes. • Typical loading conditions and reported tensile and fracture properties are used. • The FAD is capable to predict the failure mode for different cracks and loads. • The FAD can be used to reduce the conservatism of the current plugging criteria. • Appropriate tensile and fracture properties at operating conditions are required. - Abstract: Steam generator tubes (SGTs) represents up to 60% of the total primary pressure retaining boundary area of a nuclear power plant. They have been found susceptible to diverse degradation mechanisms during service. Due to the significance of a SGT failure on the plant safe operation, nuclear regulatory authorities have established tube plugging or repairing criteria which are based on the defect depth. The widespreadly used “40% criterion” proposed in the 70s is an example whose use is still recommended in the last editions of the ASME Boiler and Pressure Vessel Code. In the present work, an alternative, more realistic and less conservative methodology for SGT integrity evaluation is proposed. It is based on the Failure Assessment Diagram (FAD) and takes advantage of the recent developments in non-destructive techniques which allow a more comprehensive characterization of tube defects, i.e., depth, length, orientation and type. The proposed approach has been applied to: the study of the influence of primary and secondary stresses on tube integrity; the prediction of failure mode (i.e., ductile fracture or plastic collapse) of defective SGTs for varied crack geometries and loading conditions; the analysis of the sensibility of tensile and fracture properties with temperature. The potentiality of the FAD as a comprehensive methodology for predicting the failure loads and failure modes of flawed SGTs is highlighted.

  5. Structural integrity assessments of steam generator tubes using the FAD methodology

    International Nuclear Information System (INIS)

    Bergant, Marcos A.; Yawny, Alejandro A.; Perez Ipiña, Juan E.

    2015-01-01

    Highlights: • The Failure Assessment Diagram (FAD) is used to assess cracked steam generator tubes. • Typical loading conditions and reported tensile and fracture properties are used. • The FAD is capable to predict the failure mode for different cracks and loads. • The FAD can be used to reduce the conservatism of the current plugging criteria. • Appropriate tensile and fracture properties at operating conditions are required. - Abstract: Steam generator tubes (SGTs) represents up to 60% of the total primary pressure retaining boundary area of a nuclear power plant. They have been found susceptible to diverse degradation mechanisms during service. Due to the significance of a SGT failure on the plant safe operation, nuclear regulatory authorities have established tube plugging or repairing criteria which are based on the defect depth. The widespreadly used “40% criterion” proposed in the 70s is an example whose use is still recommended in the last editions of the ASME Boiler and Pressure Vessel Code. In the present work, an alternative, more realistic and less conservative methodology for SGT integrity evaluation is proposed. It is based on the Failure Assessment Diagram (FAD) and takes advantage of the recent developments in non-destructive techniques which allow a more comprehensive characterization of tube defects, i.e., depth, length, orientation and type. The proposed approach has been applied to: the study of the influence of primary and secondary stresses on tube integrity; the prediction of failure mode (i.e., ductile fracture or plastic collapse) of defective SGTs for varied crack geometries and loading conditions; the analysis of the sensibility of tensile and fracture properties with temperature. The potentiality of the FAD as a comprehensive methodology for predicting the failure loads and failure modes of flawed SGTs is highlighted.

  6. Heat transfer improvement due to the imposition of non-uniform wall heating for in-tube laminar forced convection

    International Nuclear Information System (INIS)

    Hajmohammadi, M.R.; Poozesh, S.; Rahmani, M.; Campo, A.

    2013-01-01

    This paper explores the bearing that a non-uniform distribution of heat flux used as a wall boundary condition exerts on the heat transfer improvement in a round pipe. Because the overall heat load is considered fixed, the heat transfer improvement is viewed through a reduction in the maximum temperature (‘hot spot’) by imposing optimal distribution of heat flux. Two cases are studied in detail 1) fully developed and 2) developing flow. Peak temperatures in the heated pipe wall are calculated via an analytical approach for the fully developed case, while a numerical simulation based on CFD is employed for the developing case. By relaxing the heat flux distribution on the pipe wall, the numerical results imply that the optimum distribution of heat flux, which minimizes the peak temperatures corresponds with the ‘descending’ distribution. Given that the foregoing approach is quite different from the ‘ascending’ heat flux distribution recommended in the literature by means of the entropy generation minimization (EGM) method, it is inferred that the optimization of heat transfer and fluid flow, in comparison with the thermodynamic optimization, may bring forth quite different guidelines for the designs of thermal systems under the same constraints and circumstances. -- Highlights: • Considered the bearing of non-uniform distribution of heat flux on the hot spots. • Determined the optimal distribution of heat flux that minimizes the hot spots. • Results are compared with those obtained by EGM method

  7. Electronic setup for fluorescence emission measurements and long-time constant-temperature maintenance of Single-Walled Carbon Nano-Tubes in water solutions

    Directory of Open Access Journals (Sweden)

    De Rosa Matteo

    2017-03-01

    Full Text Available In our previous research we have observed that the fluorescence emission from water solutions of Single-Walled Carbon Nano-Tubes (SWCNT, excited by a laser with a wavelength of 830nm, diminishes with the time. We have already proved that such a fading is a function of the storage time and the storage temperature. In order to study the emission of the SWCNT as a function of these two parameters we have designed and realized a special measurement compartment with a cuvette holder where the SWCNT solutions can be measured and stored at a fixed constant temperature for periods of time as long as several weeks. To maintain the measurement setup under a constant temperature we have designed special experimental setup based on two Peltier cells with electronic temperature control.

  8. A Systematic Method of Assessing the Durability of Wood-Frame Wall Assemblies

    DEFF Research Database (Denmark)

    Lacasse, Michael A.; Morelli, Martin

    2016-01-01

    The long-term performance in respect to moisture management within any wall assembly depends on the hygrothermal response of the wall. Critical factors in estimating the longevity of wood-frame structures include limiting the temperature range, wood moisture content, and time of exposure to condi......The long-term performance in respect to moisture management within any wall assembly depends on the hygrothermal response of the wall. Critical factors in estimating the longevity of wood-frame structures include limiting the temperature range, wood moisture content, and time of exposure...... to the effects of moisture accumulation in wall cavities. Several approaches to assessing the vulnerability of wood-frame structures to deterioration have been developed in recent years, some of which suggest applying a limit-states design approach to the performance assessment of the assembly. In this paper......, a limit-states design approach is described that forms the basis of a performance assessment method for wood-frame wall assemblies. The approach is based on the requirements set out in ISO 13823. The approach, developed for the Moisture Management of Exterior Wall Systems (MEWS) project, is described...

  9. Bioactivity and electrochemical behavior of hydroxyapatite-silicon-multi walled carbon nano-tubes composite coatings synthesized by EPD on NiTi alloys in simulated body fluid

    Energy Technology Data Exchange (ETDEWEB)

    Khalili, V., E-mail: V_khalili@sut.ac.ir [Department of Materials Engineering, Engineering Faculty, University of Bonab, Bonab (Iran, Islamic Republic of); Khalil-Allafi, J. [Research Center for Advanced Materials and Mineral Processing, Faculty of Materials Engineering, Sahand University of Technology, Tabriz (Iran, Islamic Republic of); Frenzel, J.; Eggeler, G. [Institute for Materials, Faculty of Mechanical Engineering, Ruhr-University Bochum, 44801 Bochum (Germany)

    2017-02-01

    In order to improve the surface bioactivity of NiTi bone implant and corrosion resistance, hydroxyapatite coating with addition of 20 wt% silicon, 1 wt% multi walled carbon nano-tubes and both of them were deposited on a NiTi substrate using a cathodic electrophoretic method. The apatite formation ability was estimated using immersion test in the simulated body fluid for 10 days. The SEM images of the surface of coatings after immersion in simulated body fluid show that the presence of silicon in the hydroxyapatite coatings accelerates in vitro growth of apatite layer on the coatings. The Open-circuit potential and electrochemical impedance spectroscopy were measured to evaluate the electrochemical behavior of the coatings in the simulated body fluid at 37 °C. The results indicate that the compact structure of hydroxyapatite-20 wt% silicon and hydroxyapatite-20 wt% silicon-1 wt% multi walled carbon nano-tubes coatings could efficiently increase the corrosion resistance of NiTi substrate. - Highlights: • The composite coatings of HA, Si and MWCNTs was prepared using electrophoretic deposition. • The presence of 1 wt.% MWCNTs in the HA coating provides more nucleation cites of apatite crystallites in SBF. • The presence of Si in HA coating increases the growth rate of apatite crystallites with the Ca/P atomic ratio of 1.67. • The EIS indicate the compact HA-20%Si and HA-20%Si-1%MWCNTs coatings efficiently increase corrosion resistance of NiTi. • The porous HA and HA-1%MWCNTs do not increase significantly corrosion resistance due to the easy diffusion path.

  10. Investigation of Mild Steel Thin-Wall Tubes in Unfilled and Foam-Filled Triangle, Square, and Hexagonal Cross Sections Under Compression Load

    Science.gov (United States)

    Rajak, Dipen Kumar; Kumaraswamidhas, L. A.; Das, S.

    2018-02-01

    This study has examined proposed structures with mild steel-reinforced LM30 aluminum (Al) alloy having diversely unfilled and 10 wt.% SiCp composite foam-filled tubes for improving axial compression performance. This class of material has novel physical, mechanical, and electrical properties along with low density. In the present experiment, Al alloy foams were prepared by the melt route technique using metal hydride powder as a foaming agent. Crash energy phenomena for diverse unfilled and foam-filled in mild steel thin-wall tubes (triangular, square and hexagonal) were studied as well. Compression deformation investigation was conducted at strain rates of 0.001-0.1/s for evaluating specific energy absorption (SEA) under axial loading conditions. The results were examined to measure plateau stress, maximum densification strain, and deformation mechanism of the materials. Specific energy absorption and total energy absorption capacities of the unfilled and filled sections were determined from the compressive stress-strain curves, which were then compared with each other.

  11. Assessment of YouTube videos as a source of information on medication use in pregnancy.

    Science.gov (United States)

    Hansen, Craig; Interrante, Julia D; Ailes, Elizabeth C; Frey, Meghan T; Broussard, Cheryl S; Godoshian, Valerie J; Lewis, Courtney; Polen, Kara N D; Garcia, Amanda P; Gilboa, Suzanne M

    2016-01-01

    When making decisions about medication use in pregnancy, women consult many information sources, including the Internet. The aim of this study was to assess the content of publicly accessible YouTube videos that discuss medication use in pregnancy. Using 2023 distinct combinations of search terms related to medications and pregnancy, we extracted metadata from YouTube videos using a YouTube video Application Programming Interface. Relevant videos were defined as those with a medication search term and a pregnancy-related search term in either the video title or description. We viewed relevant videos and abstracted content from each video into a database. We documented whether videos implied each medication to be "safe" or "unsafe" in pregnancy and compared that assessment with the medication's Teratogen Information System (TERIS) rating. After viewing 651 videos, 314 videos with information about medication use in pregnancy were available for the final analyses. The majority of videos were from law firms (67%), television segments (10%), or physicians (8%). Selective serotonin reuptake inhibitors (SSRIs) were the most common medication class named (225 videos, 72%), and 88% of videos about SSRIs indicated that they were unsafe for use in pregnancy. However, the TERIS ratings for medication products in this class range from "unlikely" to "minimal" teratogenic risk. For the majority of medications, current YouTube video content does not adequately reflect what is known about the safety of their use in pregnancy and should be interpreted cautiously. However, YouTube could serve as a platform for communicating evidence-based medication safety information. Copyright © 2015 John Wiley & Sons, Ltd.

  12. Assessment of dry-stone terrace wall degradation with a 3D approach

    Science.gov (United States)

    Djuma, Hakan; Camera, Corrado; Faka, Marina; Bruggeman, Adriana; Hermon, Sorin

    2016-04-01

    In the Mediterranean basin, terracing is a common element of agricultural lands. Terraces retained by dry-stone walls are used to conserve arable soil, delay erosion processes and retain rainfall runoff. Currently, agricultural land abandonment is widespread in the Mediterranean region leading to terrace wall failure due to lack of maintenance and consequently an increase in soil erosion. The objective of this study is to test the applicability of digital 3D documentation on mountainous agricultural areas for assessing changes in terrace wall geometry, including terrace wall failures and associated soil erosion. The study area is located at 800-1100 m above sea level, in the Ophiolite complex of the Troodos Mountains in Cyprus. Average annual precipitation is 750 mm. Two sites with dry-stone terraces were selected for this study. The first site had a sequence of three terrace walls that were surveyed. The uppermost terrace wall was collapsed at several locations; the middle at few locations; and the lowest was still intact. Three fieldwork campaigns were conducted at this site: during the dry season (initial conditions), the middle and end of the wet season. The second site had one terrace wall that was almost completely collapsed. This terrace was restored during a communal terrace rehabilitation event. Two fieldwork campaigns were conducted for this terrace: before and after the terrace wall restoration. Terrace walls were documented with a set of digital images, and transformed into a 3D point cloud (using web-based services and commercial software - Autodesk 123D catch and Menci Software uMap, respectively). A set of points, registered with the total station and geo-referenced with a GPS, enabled the scaling of the 3D model and aligning the terrace walls within the same reference system. The density (distance between each point) of the reconstructed point clouds is 0.005 m by Umap and 0.025 m by 123D Catch. On the first site, the model analysis identified wall

  13. Risk assessment of severe accident-induced steam generator tube rupture

    International Nuclear Information System (INIS)

    1998-03-01

    This report describes the basis, results, and related risk implications of an analysis performed by an ad hoc working group of the U.S. Nuclear Regulatory Commission (NRC) to assess the containment bypass potential attributable to steam generator tube rupture (SGTR) induced by severe accident conditions. The SGTR Severe Accident Working Group, comprised of staff members from the NRC's Offices of Nuclear Reactor Regulation (NRR) and Nuclear Regulatory Research (RES), undertook the analysis beginning in December 1995 to support a proposed steam generator integrity rule. The work drew upon previous risk and thermal-hydraulic analyses of core damage sequences, with a focus on the Surry plant as a representative example. This analysis yielded new results, however, derived by predicting thermal-hydraulic conditions of selected severe accident scenarios using the SCDAP/RELAP5 computer code, flawed tube failure modeling, and tube failure probability estimates. These results, in terms of containment bypass probability, form the basis for the findings presented in this report. The representative calculation using Surry plant data indicates that some existing plants could be vulnerable to containment bypass resulting from tube failure during severe accidents. To specifically identify the population of plants that may pose a significant bypass risk would require more definitive analysis considering uncertainties in some assumptions and plant- and design-specific variables. 46 refs., 62 figs., 37 tabs

  14. Measuring a film flowing down a tube inner wall using a laser focus displacement meter and an image-processing method

    International Nuclear Information System (INIS)

    Takamasa, Tomoji; Kobayashi, Kenji

    1999-01-01

    To elucidate details of the fascinating nonlinear phenomena of waves on a film, spatial temporal knowledge of the interfacial waves is essential. This paper presents an experimental study on waves on a film flowing down a vertical tube inner wall measured with a laser focus displacement meter (LFD) and an image-processing method. As a result, the film thickness was measured within a 1% margin of error by LFD, and the wave velocity was measured within a 10% margin of error by the image-processing. The experimental results are summarized as follows: At entry length L = 900 mm, the wave becomes a two-wave system. In the entry region, L = 216 mm, and 400 mm, the wave amplitude decreases as the flow rate increases, in the same manner as that in a film flowing down a plate wall. The velocity measured by the image processing agreed well with that calculated using Nusselt's theoretical equation and the Ito-Sasaki empirical equation for Reynolds numbers < 250. (author)

  15. Automated image segmentation and registration of vessel wall MRI for quantitative assessment of carotid artery vessel wall dimensions and plaque composition

    NARCIS (Netherlands)

    Klooster, Ronald van 't

    2014-01-01

    The main goal of this thesis was to develop methods for automated segmentation, registration and classification of the carotid artery vessel wall and plaque components using multi-sequence MR vessel wall images to assess atherosclerosis. First, a general introduction into atherosclerosis and

  16. Investigation and assessment of wall heat transfer correlations in SPACE code

    International Nuclear Information System (INIS)

    Kim, Jung Woo; Kim, Kyung Doo; Moon, Sang Ki; Choi, Ki Yong; Park, Hyun Sik

    2010-06-01

    SPACE, which is a safety analysis code for nuclear power plants, has been developed to analyze the multidimensional, two-component and three-field flow. This code can be applied to safety analysis for approval which is thermal-hydraulic analysis to support the nuclear power station design, establishment of accident ease strategy, development of operating guide line, experiment plan and analysis. To do so, SPACE code has 12 wall heat transfer mode and the corresponding models and correlations to deal with the physical heat transfer phenomenon in wall surface. In this report, the physical correlation models regarding the wall heat transfer are explained and their performance is assessed against several SET

  17. Prediction of the Wall Factor of Arbitrary Particle Settling through Various Fluid Media in a Cylindrical Tube Using Artificial Intelligence

    Directory of Open Access Journals (Sweden)

    Mingzhong Li

    2014-01-01

    Full Text Available Considering the influence of particle shape and the rheological properties of fluid, two artificial intelligence methods (Artificial Neural Network and Support Vector Machine were used to predict the wall factor which is widely introduced to deduce the net hydrodynamic drag force of confining boundaries on settling particles. 513 data points were culled from the experimental data of previous studies, which were divided into training set and test set. Particles with various shapes were divided into three kinds: sphere, cylinder, and rectangular prism; feature parameters of each kind of particle were extracted; prediction models of sphere and cylinder using artificial neural network were established. Due to the little number of rectangular prism sample, support vector machine was used to predict the wall factor, which is more suitable for addressing the problem of small samples. The characteristic dimension was presented to describe the shape and size of the diverse particles and a comprehensive prediction model of particles with arbitrary shapes was established to cover all types of conditions. Comparisons were conducted between the predicted values and the experimental results.

  18. Prediction of the Wall Factor of Arbitrary Particle Settling through Various Fluid Media in a Cylindrical Tube Using Artificial Intelligence

    Science.gov (United States)

    Li, Mingzhong; Xue, Jianquan; Li, Yanchao; Tang, Shukai

    2014-01-01

    Considering the influence of particle shape and the rheological properties of fluid, two artificial intelligence methods (Artificial Neural Network and Support Vector Machine) were used to predict the wall factor which is widely introduced to deduce the net hydrodynamic drag force of confining boundaries on settling particles. 513 data points were culled from the experimental data of previous studies, which were divided into training set and test set. Particles with various shapes were divided into three kinds: sphere, cylinder, and rectangular prism; feature parameters of each kind of particle were extracted; prediction models of sphere and cylinder using artificial neural network were established. Due to the little number of rectangular prism sample, support vector machine was used to predict the wall factor, which is more suitable for addressing the problem of small samples. The characteristic dimension was presented to describe the shape and size of the diverse particles and a comprehensive prediction model of particles with arbitrary shapes was established to cover all types of conditions. Comparisons were conducted between the predicted values and the experimental results. PMID:24772024

  19. Experimental assessment of borehole wall drilling damage in basaltic rocks

    International Nuclear Information System (INIS)

    Fuenkajorn, K.; Daemen, J.J.K.

    1986-06-01

    Ring tension tests, permeability tests, and microscopic fracture studies have been performed to investigate the borehole damage induced at low confining pressure by three drilling techniques (diamond, percussion and rotary). Specimens are drilled with three hole sizes (38, 76, and 102 mm diameter) in Pomona basalt and Grande basaltic andesite. The damaged zone is characterized in terms of fractures and fracture patterns around the hole, and in terms of tensile strength reduction of the rock around the holes. Experimental results show that the thickness of the damaged zone around the hole ranges from 0.0 to 1.7 mm. A larger drill bit induces more wall damage than does a smaller one. Different drilling techniques show different damage characteristics (intensity and distribution). Damage characteristics are governed not only by drilling parameters (bit size, weight on bit, rotational speed, diamond radius, and energy), but also by properties of the rock. The weaker rock tends to show more intense damage than does the stronger one. Cracks within grains or cleavage fractures are predominant in slightly coarser grained rock (larger than 0.5 mm grain size) while intergranular cracks are predominant in very fine grained rock (smaller than 0.01 mm grain size). The damaged zones play no significant role in the flow path around a borehole plug

  20. Economic assessment of single-walled carbon nanotube processes

    Science.gov (United States)

    Isaacs, J. A.; Tanwani, A.; Healy, M. L.; Dahlben, L. J.

    2010-02-01

    The carbon nanotube market is steadily growing and projected to reach 1.9 billion by 2010. This study examines the economics of manufacturing single-walled carbon nanotubes (SWNT) using process-based cost models developed for arc, CVD, and HiPco processes. Using assumed input parameters, manufacturing costs are calculated for 1 g SWNT for arc, CVD, and HiPco, totaling 1,906, 1,706, and 485, respectively. For each SWNT process, the synthesis and filtration steps showed the highest costs, with direct labor as a primary cost driver. Reductions in production costs are calculated for increased working hours per day and for increased synthesis reaction yield (SRY) in each process. The process-based cost models offer a means for exploring opportunities for cost reductions, and provide a structured system for comparisons among alternative SWNT manufacturing processes. Further, the models can be used to comprehensively evaluate additional scenarios on the economics of environmental, health, and safety best manufacturing practices.

  1. Economic assessment of single-walled carbon nanotube processes

    Energy Technology Data Exchange (ETDEWEB)

    Isaacs, J. A., E-mail: jaisaacs@coe.neu.ed [Northeastern University, NSF Center for High-rate Nanomanufacturing (United States); Tanwani, A. [Infojini Solutions Inc. (United States); Healy, M. L. [Babcock Power Inc. (United States); Dahlben, L. J. [Northeastern University, NSF Center for High-rate Nanomanufacturing (United States)

    2010-02-15

    The carbon nanotube market is steadily growing and projected to reach $1.9 billion by 2010. This study examines the economics of manufacturing single-walled carbon nanotubes (SWNT) using process-based cost models developed for arc, CVD, and HiPco processes. Using assumed input parameters, manufacturing costs are calculated for 1 g SWNT for arc, CVD, and HiPco, totaling $1,906, $1,706, and $485, respectively. For each SWNT process, the synthesis and filtration steps showed the highest costs, with direct labor as a primary cost driver. Reductions in production costs are calculated for increased working hours per day and for increased synthesis reaction yield (SRY) in each process. The process-based cost models offer a means for exploring opportunities for cost reductions, and provide a structured system for comparisons among alternative SWNT manufacturing processes. Further, the models can be used to comprehensively evaluate additional scenarios on the economics of environmental, health, and safety best manufacturing practices.

  2. Assessment of inferior wall in 123I-metaiodobenzylguanidine myocardial SPECT in diabetic patients

    International Nuclear Information System (INIS)

    Fukumoto, Yoshihiro; Kuroda, Yasuhisa; Ohta, Jun; Osono, Ken; Saitou, Miyoko; Suzuki, Mituaki; Nakajima, Toshiki

    1994-01-01

    A phantom experiment and a clinical assessment have been made with the purpose of investigating the causes of low accumulation and deficiency of the inferior wall in 123 I-metaiodobenzylguanidine (MIBG) myocardial SPECT and the method for its evaluation. By the phantom experiment, assessments were made regarding (1) influence of the liver positioned adjacently; and (2) involvement of absorption and attenuation of the inferior wall. For the clinical assessment, 84 patients with diabetes in whom no abnormality was observed by exercise myocardial SPECT ( 201 TlCl) and 5 cases of inferior myocardial infarction (OMI group) were adopted as subjects. The inferior walls were evaluated as visually deficient because of the adjacently-positioned liver, but no low value was exhibited by quantitative evaluation. By pulmonary mediastinal phantom (-), improvement of the inferior wall was observed visually and quantitatively, compared with pulmonary mediastinal phantom (+). By quantitative evaluation, the patients were classified into normal MIBG group (N group); segmentally deficient group (S group); and non-accumulated group (DH group). In addition, S group was classified by severity score into those from S 1 to S 4 groups. No significant difference was observed in Relative Regional Uptake (RRU) in the inferior wall between S 4 group and OMI group. To sum up, we considered the causes for low accumulation and deficiency of the inferior wall, (1) adjacently-positioned liver; (2) absorption and attenuation; and (3) the lesion itself. Visual evaluation is not sufficient as the evaluating method. Quantitative evaluation becomes necessary. (author)

  3. Corrosion and Heat Transfer Characteristics of Water Dispersed with Carboxylate Additives and Multi Walled Carbon Nano Tubes

    Science.gov (United States)

    Moorthy, Chellapilla V. K. N. S. N.; Srinivas, Vadapalli

    2016-10-01

    This paper summarizes a recent work on anti-corrosive properties and enhanced heat transfer properties of carboxylated water based nanofluids. Water mixed with sebacic acid as carboxylate additive found to be resistant to corrosion and suitable for automotive environment. The carboxylated water is dispersed with very low mass concentration of carbon nano tubes at 0.025, 0.05 and 0.1 %. The stability of nanofluids in terms of zeta potential is found to be good with carboxylated water compared to normal water. The heat transfer performance of nanofluids is carried out on an air cooled heat exchanger similar to an automotive radiator with incoming air velocities across radiator at 5, 10 and 15 m/s. The flow Reynolds number of water is in the range of 2500-6000 indicating developing flow regime. The corrosion resistance of nanofluids is found to be good indicating its suitability to automotive environment. There is a slight increase in viscosity and marginal decrease in the specific heat of nanofluids with addition of carboxylate as well as CNTs. Significant improvement is observed in the thermal conductivity of nanofluids dispersed with CNTs. During heat transfer experimentation, the inside heat transfer coefficient and overall heat transfer coefficient has also improved markedly. It is also found that the velocity of air and flow rate of coolant plays an important role in enhancement of the heat transfer coefficient and overall heat transfer coefficient.

  4. Preparing hydroxyapatite-silicon composite suspensions with homogeneous distribution of multi-walled carbon nano-tubes for electrophoretic coating of NiTi bone implant and their effect on the surface morphology

    International Nuclear Information System (INIS)

    Khalili, Vida; Khalil-Allafi, Jafar; Xia, Wei; Parsa, Alireza B.; Frenzel, Jan; Somsen, Christoph; Eggeler, Gunther

    2016-01-01

    Graphical abstract: - Highlights: • The stable composite suspensions of hydroxyapatite, silicon and multi-walled carbon nano-tubes was prepared using functionalization of and multi-walled carbon nano-tubes in HNO_3 vapor and triethanolamine as dispersing agent. • The zeta potential of composite suspensions is less than that of hydroxyapatite suspension. • The silicon particles presence in suspension causes to decrease the charge carrier in suspension and current density during electrophoretic deposition. • The orientation of multi-walled carbon nano-tubes to parallel direction of the applied electric field during electrophoretic deposition can facilitate their moving towards the cathode and increase current density. • The more zeta potential of suspension, the lower roughness of coatings during electrophoretic deposition. - Abstract: Preparing a stable suspension is a main step towards the electrophoretically depositing of homogeneous and dense composite coatings on NiTi for its biomedical application. In the present study, different composite suspensions of hydroxyapatite, silicon and multi-walled carbon nano-tubes were prepared using n-butanol and triethanolamine as media and dispersing agent, respectively. Multi-walled carbon nanotubes were first functionalized in the nitric acid vapor for 15 h at 175 °C, and then mixed into suspensions. Thermal desorption spectroscopy profiles indicate the formation of functional groups on multi-walled carbon nano-tubes. An excellent suspension stability can be achieved for different amounts of triethanolamine. The amount of triethanolamine can be increased by adding a second component to a stable hydroxyapatite suspension due to an electrostatic interaction between components in suspension. The stability of composite suspension is less than that of the hydroxyapatite suspension, due to density differences, which under the gravitational force promote the demixing. The scanning electron microscopy images of the

  5. Fallopian tube recanalisation using dedicated radiographic tubal assessment set in angiography suite

    International Nuclear Information System (INIS)

    Al-Omari, M.H; Rousan, L.; Al-balas, H.; Alawneh, K.; El-heis, M.; Al-mnayyis, A.; Obeidat, N.; Amarin, Z.; Zayed, F.; Omari, Z.; Hanania, R.

    2014-01-01

    Fallopian tube recanalisation (FTR) for proximal fallopian tube obstruction (PFTO) is considered a good treatment option for tubal infertility. The aim of this study was to assess the safety and the technical and clinical success rates of FTR using a dedicated radiographic tubal assessment set (FluoroSet®) in the angiography suite. This study is a retrospective analysis of data prospectively collected between February 2007 and June 2011 at King Abdullah University Hospital, Irbid, Jordan. During this period, 61 patients affected by PFTO underwent FTR using FluoroSet® at our institution. The mean age of patients was 34 years (range 20-45 years), and the mean duration of infertility was 4 years (range 2-14 years). The procedure was performed with conscious sedation under fluoroscopic guidance in the angiography suite. The obstructed tube was accessed with a 5-Fr multipurpose catheter, and the obstruction was crossed with a 0.35-Fr hydrophilic guide wire until the wire coiled freely into the peritoneal cavity. Patency of the tube was then confirmed by selective salpingiogram. Technical success rate was recorded, and patients were followed up for evidence of pregnancy over 12 months. The procedure was technically successful in all patients. Minor bleeding and postprocedural pain occurred in most patients; however, there were no major complications encountered. Twenty-five patients (41%) became pregnant. Successful deliveries of full-term infants were reported in 21 patients (84%). Miscarriage was reported in four patients (16%). No ectopic pregnancies were detected, and all deliveries were full-term. The technical success rate was 100% and the clinical success rate was 41%. Selective salpingography and FTR using FluoroSet® is a safe and effective method. FTR is recommended as the first intervention in patients with PFTO. In experienced hands with dedicated equipment and in an appropriate setting, the success rate is high, and this treatment should be offered to

  6. Analysis of the ballooning deformation of an internally pressurized thin-wall tube during fast thermal transients

    International Nuclear Information System (INIS)

    Lin, E.I.H.

    1977-01-01

    A large-strain, time-dependent thermoplastic analysis of ballooning deformation was developed. The true (or lagorithmic) strains, the Von Mises yield criterion and Prandtl-Reuss flow rules were used. The constitutive equation was expressed in terms of the temperature, effective stress, strain and strain rate. Material isotropy was assumed as a first approximation; note that at high temperatures even zircaloy tends to lose a substantial amount of its low-temperature anisotropy. The axisymmetry of ballooning was also assumed, which has actually been verified by numerous experiments to be accurate throughout the course of ballooning, except in the final stage when rupture is imminent. The thin-shell approximation was made, which proved to be adequate for the standard fuel claddings and which was advantageous in that the averaged state of stress was rendered determinate. The analysis led to a set of non-linear ordinary differential equations, which was then integrated by a fifth-order Runge-Kutta routine. The general formulation allows for a direct interpretation of the experimentally-observed effects of the heating rate and cladding axial constraints on the ballooning behavior. Its implications on the flow-blockage and cladding-rupture evaluations were discussed. The analysis was applied to zircaloy claddings subjected to simulated thermal transient conditions. Most of the required material properties were taken from the existing uniaxial tensile test data. Analyses were performed at a uniform heating rate of 115 0 C/sec with internal pressures ranging from 100 to 1200 psi. Satisfactory agreement was obtained between the predictions and the diametral strain-time data available from tube-burst tests

  7. Room temperature elastic--plastic response of thin-walled tubes subjected to nonradial combinations of axial and torsional loadings

    International Nuclear Information System (INIS)

    Liu, K.C.

    1975-01-01

    Two tubular specimens of type 304 stainless steel with uniform thin walls were subjected to a program of segmental combined tension/compression and torsion loadings at room temperature. A proportional, or radial, loading into the plastic range was initially applied to each specimen. Two nonproportional (nonradial) loadings along straight line segments for which neither the loading paths nor their linear extrapolations passed through the origin of the stress space were then applied. The axial and torsional stress-strain curves for these segmental prestress loadings were plotted. Hence, the stress-strain response characteristics for nonproportional loadings as well as for proportional loading can be studied. In addition, the axial and torsional plastic strain components were calculated, and the total plastic strain trajectories were plotted in a plastic strain space. Finally, using results from a detailed study of yield surfaces, which was performed for the first specimen, a spectrum of initial and subsequent yield curves corresponding to the segmental prestress loadings is presented. (U.S.)

  8. Assessment of CCFL model of RELAP5/MOD3 against simple vertical tubes and rod bundle tests

    International Nuclear Information System (INIS)

    Cho, Sung Jae; Arne, Nam Sung; Chung, Bub Dong; Kim, Hho Jung

    1991-01-01

    The CCFL model used in RELAP5/MOD3 version 5m5 has been assessed against simple vertical tubes and rod bundle tests performed at a facility of Korea Atomic Energy Research Institute. The effect of changes in tube diameter and nodalization of tube section were investigated. The roles of interfacial drags on the flooding characteristics are discussed. Difference between the calculation and the experiment are also discussed. A comparison between model assessment results and the test data showed that the calculated value lay well on the experimental flooding curve specified by user, but the pressure jump before onset of flooding was not calculated

  9. Metabolic assessment and enteral tube feeding usage in children with acute neurological diseases

    Directory of Open Access Journals (Sweden)

    Heitor Pons Leite

    Full Text Available OBJECTIVE: To report on acquired experience of metabolic support for children with acute neurological diseases, emphasizing enteral tube feeding usage and metabolic assessment, and also to recommend policies aimed towards improving its implementation. DESIGN: Retrospective analysis. SETTING: Pediatric Intensive Care Unit of Hospital do Servidor Público Estadual de São Paulo. SUBJECTS: 44 patients consecutively admitted to the Pediatric ICU over a period of 3 years who were given nutrition and metabolic support for at least 72 hours. Head trauma, CNS infections and craniotomy post-operative period following tumor exeresis were the main diagnoses. MEASUREMENTS: Records of protein-energy intake, nutrient supply route, nitrogen balance and length of therapy. RESULTS: From a total of 527 days of therapy, single parenteral nutrition was utilized for 34.3% and single enteral tube feeding for 79.1% of that period. 61.4% of the children were fed exclusively via enteral tube feeding, 9.1% via parenteral and 39.5 % by both routes. The enteral tube feeding was introduced upon admission and transpyloric placement was successful in 90% of the cases. Feeding was started 48 hours after ICU admission. The caloric goal was achieved on the 7th day after admission, and thereafter parenteral nutrition was interrupted. The maximum energy supply was 104.2 ± 23.15 kcal/kg. The median length of therapy was 11 days (range 4-38. None of the patients on tube feeding developed GI tract bleeding, pneumonia or bronchoaspiration episodes and, of the 4 patients who were given exclusive TPN, 2 developed peptic ulcer. The initial urinary urea nitrogen was 7.11 g/m2 and at discharge 6.44 g/m2. The protein supply increased from 1.49 g/kg to 3.65 g/kg (p< 0.01. The nitrogen balance increased from -7.05 to 2.2 g (p< 0.01. CONCLUSIONS: Children with acute neurological diseases are hypercatabolic and have high urinary nitrogen losses. The initial negative nitrogen balance can be

  10. Assessment of horizontal in-tube condensation models using MARS code. Part I: Stratified flow condensation

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Seong-Su [Department of Engineering Project, FNC Technology Co., Ltd., Bldg. 135-308, Seoul National University, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Department of Nuclear Engineering, Seoul National University, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Hong, Soon-Joon, E-mail: sjhong90@fnctech.com [Department of Engineering Project, FNC Technology Co., Ltd., Bldg. 135-308, Seoul National University, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Park, Ju-Yeop; Seul, Kwang-Won [Korea Institute of Nuclear Safety, 19 Kuseong-dong, Yuseong-gu, Daejon (Korea, Republic of); Park, Goon-Cherl [Department of Nuclear Engineering, Seoul National University, Gwanak-gu, Seoul 151-744 (Korea, Republic of)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer This study collected 11 horizontal in-tube condensation models for stratified flow. Black-Right-Pointing-Pointer This study assessed the predictive capability of the models for steam condensation. Black-Right-Pointing-Pointer Purdue-PCCS experiments were simulated using MARS code incorporated with models. Black-Right-Pointing-Pointer Cavallini et al. (2006) model predicts well the data for stratified flow condition. Black-Right-Pointing-Pointer Results of this study can be used to improve condensation model in RELAP5 or MARS. - Abstract: The accurate prediction of the horizontal in-tube condensation heat transfer is a primary concern in the optimum design and safety analysis of horizontal heat exchangers of passive safety systems such as the passive containment cooling system (PCCS), the emergency condenser system (ECS) and the passive auxiliary feed-water system (PAFS). It is essential to analyze and assess the predictive capability of the previous horizontal in-tube condensation models for each flow regime using various experimental data. This study assessed totally 11 condensation models for the stratified flow, one of the main flow regime encountered in the horizontal condenser, with the heat transfer data from the Purdue-PCCS experiment using the multi-dimensional analysis of reactor safety (MARS) code. From the assessments, it was found that the models by Akers and Rosson, Chato, Tandon et al., Sweeney and Chato, and Cavallini et al. (2002) under-predicted the data in the main condensation heat transfer region, on the contrary to this, the models by Rosson and Meyers, Jaster and Kosky, Fujii, Dobson and Chato, and Thome et al. similarly- or over-predicted the data, and especially, Cavallini et al. (2006) model shows good predictive capability for all test conditions. The results of this study can be used importantly to improve the condensation models in thermal hydraulic code, such as RELAP5 or MARS code.

  11. A risk-informed approach to the assessment of DHC initiation in pressure tubes

    International Nuclear Information System (INIS)

    Sahoo, A.K.; Pandey, M.D.

    2009-01-01

    The delayed hydride cracking (DHC) of pressure tubes is a serious form of degradation in the reactor core. Flaws in pressure tubes generated by fretting or any other mechanism are potential stress raisers that could become sites of DHC initiation under right circumstances. CSA standard N285.8 recommends deterministic and probabilistic procedures for the assessment of potential for DHC initiation from planar flaws. The deterministic method is simple, but it lacks a risk-informed basis for the assessment. A full probabilistic method based on simulations is tedious to implement. This paper presents an innovative, semi-probabilistic method that bridges the gap between a simple deterministic analysis and complex simulations. In the proposed method, the deterministic assessment criterion of CSA N285.8 standard is calibrated to specified target probabilities of DHC initiation using the concept of partial factors. The main advantage of the proposed approach is that it provides a practical, risk-informed basis for DHC initiation assessment while retaining the simplicity of the deterministic method. (author)

  12. In vitro assessment of some sperm function following exposure to levonorgestrel in human fallopian tubes

    Directory of Open Access Journals (Sweden)

    Hermanny Alexia

    2012-01-01

    Full Text Available Abstract Background The mechanism of action of levonorgestrel (LNG as emergency contraception (EC remains a subject of debate and its effect on sperm function has been only partially explained. The aim of this study was to assess whether LNG at a similar dose to those found in serum following oral intake for EC could affect spermatozoa when exposed to human fallopian tubes in vitro. Methods Fifteen mini-laparotomies were performed, the side on which ovulation occurred was recorded, and both tubes were removed and perfused with a suspension containing 1 × 10(6 motile spermatozoa, with or without LNG. Following 4-hour incubation, the tubes were sectioned to separate the isthmus and the ampulla. Each segment was flushed and the material was evaluated to quantify the number of motile sperm, the number of spermatozoa adhering to the oviductal epithelium and the acrosome reaction (AR rate. Results The addition of LNG did not significantly alter the number of recovered motile spermatozoa either at the isthmus or at the ampulla, nor did it have any effect on the number of recovered spermatozoa adhered to the human tubal epithelium. Furthermore, LNG did not affect the AR rate. No significant differences were found even when the side on which ovulation occurred was taken into account. Conclusions In a similar dose to that observed in serum following oral intake for EC, LNG had no effect on the number of motile spermatozoa recovered from the human fallopian tubes in vitro, on their adhesion to the tubal epithelium, distribution or AR rate. The possible effect of LNG as EC on sperm function remains poorly understood.

  13. A review of recent advances in the role of leak-before-break concept in assessments of flaws detected in CANDU pressure tubes

    International Nuclear Information System (INIS)

    Crespi, J.C.

    1994-01-01

    If a crack develops in a pressure tube, the leak is detected by monitoring the moisture in the gas annulus and the reactor shutdown before it becomes unstable. Because the delayed hydride cracking has been associated to date with all pressure tube failures at a rolled joints, the delayed hydride cracking is considered to be the dominant mecanism by which the flaws can grow to a size which exceeds the critical crack length. For the delayed hydride cracking failure mode leak-before-break is used as defense in depth against unstable rupture. The methodology depends on showing than the time available to detect a delayed hydride crack is much greater that the time required to detect it in the gas annulus. The time available is estimated from measurements of: (a) axial delayed hydride crack growth rates, (b) crack lengths at penetrations of the tube wall when leakage first occurs and (c) critical crack lengths at instability when a crack is growing by the delayed hydride cracking mechanism. A review of recent advances in the experimental data used in leak-before-break assessment are presented and discussed. (author). 17 refs, 6 figs, 2 tabs

  14. Numerical assessment and comparison of heat transfer characteristics of supercritical water in bare tubes and tubes with heat transfer enhancing appendages

    International Nuclear Information System (INIS)

    Farah, Amjad; Harvel, Glenn; Pioro, Igor

    2015-01-01

    Computational Fluid Dynamics (CFD) is a numerical approach to model fluids in multidimensional space using the Navier-Stokes equations and databases of fluid properties to arrive at a full simulation of a fluid dynamics and heat transfer system. A numerical study on heat transfer to supercritical water (SCW) flowing in a vertical tube is carried out using the ANSYS FLUENT code and employing the SST k-ω turbulence model. The 3D mesh consists of a 1/8 section (45deg radially) of a bare tube. The numerical results on wall temperature distributions under normal and deteriorated heat transfer conditions are compared to experimental results. The same geometry is then simulated with an orifice to study the effect of geometrical perturbation on the flow and heat transfer characteristics of SCW. The orifice is placed areas to test the effect on normal, deteriorated and enhanced heat transfer regimes. The flow effects and heat transfer characteristics will be studied around the appendages to arrive at a fundamental understanding of the phenomena related to supercritical water turbulence. (author)

  15. Functionalized Multi walled Carbon Nano tubes-Reinforced Viny lester/Epoxy Blend Based Nano composites: Enhanced Mechanical, Thermal, and Electrical Properties

    International Nuclear Information System (INIS)

    Praharaj, A. P.; Behera, D.; Bastia, T. K.; Rout, A. K.

    2015-01-01

    This paper presents a study on the mechanical, thermal, and electrical characterization of a new class of low cost multiphase nano composites consisting of Vinyl ester resin/epoxy (VER/EP) blend (40:60 w/w) reinforced with amine functionalized multi walled carbon nano tubes (f-MWCNTs). Five different sets of VER/EP nano composites are fabricated with addition of 0, 1, 3, 5, and 7 wt.% of f-MWCNTs. A detailed investigation of mechanical properties like tensile strength, impact strength, Young’s modulus, and hardness, thermal properties like thermogravimetric analysis (TGA) and thermal conductivity, electrical properties like dielectric strength, dielectric constant, and electrical conductivity, and corrosive and swelling properties of the nano composites has been carried out. Here, we report significant improvement in all the above properties of the fabricated nano composites with nano filler (f-MWCNTs) addition compared to the virgin blend (0 wt. nano filler loading). The properties are best observed in case of 5 wt.% nano filler loading with gradual deterioration thereafter which may be due to the nucleating tendency of the nano filler particles. Thus the above nano composites could be a preferable candidate for a wide range of structural, thermal, electrical, and solvent based applications.

  16. Determining the Surfactant Consistent with Concrete in order to Achieve the Maximum Possible Dispersion of Multi walled Carbon Nano tubes in Keeping the Plain Concrete Properties

    International Nuclear Information System (INIS)

    Adresi, M.; Hassani, A.; Javadian, S.; Tulliani, J. M.

    2016-01-01

    A new surfactant combination compatible with concrete formulation is proposed to avoid unwanted air bubbles created during mixing process in the absence of a defoamer and to achieve the uniform and the maximum possible dispersion of multi walled carbon nano tubes (MWCNTs) in water and subsequently in concrete. To achieve this goal, three steps have been defined: (1) concrete was made with different types and amount of surfactants containing a constant amount of MWCNTs (0.05 wt%) and the air bubbles were eliminated with a proper defoamer. (2) Finding a compatible surfactant with concrete compositions and eliminating unwanted air bubbles in the absence of a common defoamer are of fundamental importance to significantly increase concrete mechanical properties. In this step, the results showed that the poly carboxylate super plasticizer (SP-C) (as a compatible surfactant) dispersed MWCNTs worse than SDS/DTAB but unwanted air bubbles were removed, so the defoamer can be omitted in the mixing process. (3) To solve the problem, a new compatible surfactant composition was developed and different ratios of surfactants were tested and evaluated by means of performance criteria mentioned above. The results showed that the new surfactant composition (SDS and SP-C) can disperse MWCNTs around 24% more efficiently than the other surfactant compositions.

  17. Using a Bedside Video-assisted Test Tube Test to Assess Stoma Viability: A Report of 4 Cases.

    Science.gov (United States)

    Ahmad, Sarwat; Turner, Keli; Shah, Paulesh; Diaz, Jose

    2016-07-01

    Mucosal discoloration of an intestinal stoma may indicate self-limited venous congestion or necrosis necessitating operative revision. A common bedside technique to assess stoma viability is the "test tube test". A clear tube is inserted into the stoma and a hand-held light is used to assess the color of the stoma. A technique (video-assisted test tube test [VATTT]) developed by the authors utilizes a standard video bronchoscope inserted into a clear plastic blood collection tube to visually inspect and assess the mucosa. This technique was evaluated in 4 patients (age range 49-72 years, all critically ill) with a discolored stoma after emergency surgery. In each case, physical exam revealed ischemic mucosa at the surface either immediately after surgery or after worsening hypotension weeks later. Serial test tube test assessments were ambiguous when trying to assess deeper mucosa. The VATTT assessment showed viable pink mucosa beneath the surface and until the fascia was revealed in 3 patients. One (1) patient had mucosal ischemia down to the fascia, which prompted operative revision of the stoma. The new stoma was assessed with a VATTT and was viable for the entire length of the stoma. VATTT provided an enhanced, magnified, and clearer way to visually assess stoma viability in the postoperative period that can be performed at the bedside with no adverse events. It may prevent unnecessary relaparotomy or enable earlier diagnosis of deep ostomy necrosis. Validity and reliability studies are warranted.

  18. Approach to Assessing the Long-term Performance of Wall Assemblies – Durability of Low-rise Wood-frame walls

    DEFF Research Database (Denmark)

    Lacasse, Michael A.; Morelli, Martin

    2017-01-01

    a limit-states design (LSD) approach to the performance assessment of the assembly. In this paper emphasis is placed on a further development of the LSD approach within the context of requirements set out in ISO 13823 “General principles on the design of structures for durability”. An example is presented...... in which the LSD approach is applied to low-rise wood-frame walls, as are built in North America, and that incorporate drainage components, such components forming part of a rain screen wall assembly. The use of this approach permits determining whether wall assemblies incorporating novel components...

  19. pH within pores in plant fiber cell walls assessed by Fluorescence Ratio Imaging

    DEFF Research Database (Denmark)

    Hidayat, Budi Juliman; Thygesen, Lisbeth Garbrecht; Johansen, Katja Salomon

    2013-01-01

    The pH within cell wall pores of filter paper fibers and hemp fibers was assessed by Fluorescence Ratio Imaging (FRIM). It was found that the Donnan effect affected the pH measured within the fibers. When the conductivity of the added liquid was low (0. 7 mS), pH values were lower within the cell...

  20. Assessment of Eustachian tube function in patients with tympanic membrane retraction and in normal subjects.

    Science.gov (United States)

    Canali, Inesângela; Petersen Schmidt Rosito, Letícia; Siliprandi, Bruno; Giugno, Cláudia; Selaimen da Costa, Sady

    The diagnosis of Eustachian tube dysfunctions is essential for better understanding of the pathogenesis of chronic otitis media. A series of tests to assess tube function are described in the literature; however, they are methodologically heterogeneous, with differences ranging from application protocols to standardization of tests and their results. To evaluate the variation in middle ear pressure in patients with tympanic membrane retraction and in normal patients during tube function tests, as well as to evaluate intra-individual variation between these tests. An observational, contemporary, cross-sectional study was conducted, in which the factor under study was the variation in middle ear pressure during tube function tests (Valsalva maneuver, sniff test, Toynbee maneuver) in healthy patients and in patients with mild and moderate/severe tympanic retraction. A total of 38 patients (76 ears) were included in the study. Patients underwent tube function tests at two different time points to determine pressure measurements after each maneuver. Statistical analysis was performed using SPSS software, version 18.0, considering p-values <0.05 as statistically significant. Mean (standard deviation) age was 11 (2.72) years; 55.3% of patients were male and 44.7% female. The prevalence of type A tympanogram was higher among participants with healthy ears and those with mild retraction, whereas type C tympanograms were more frequent in the moderate/severe retraction group. An increase in middle ear pressure was observed during the Valsalva maneuver at the first time point evaluated in all three groups of ears (p=0.012). The variation in pressure was not significant either for the sniff test or for the Toynbee maneuver at the two time points evaluated (p≥0.05). Agreement between measurements obtained at the two different time points was weak to moderate for all tests in all three groups of ears, and the variations in discrepancy between measurements were higher in ears

  1. Assessing the Content of YouTube Videos in Educating Patients Regarding Common Imaging Examinations.

    Science.gov (United States)

    Rosenkrantz, Andrew B; Won, Eugene; Doshi, Ankur M

    2016-12-01

    To assess the content of currently available YouTube videos seeking to educate patients regarding commonly performed imaging examinations. After initial testing of possible search terms, the first two pages of YouTube search results for "CT scan," "MRI," "ultrasound patient," "PET scan," and "mammogram" were reviewed to identify educational patient videos created by health organizations. Sixty-three included videos were viewed and assessed for a range of features. Average views per video were highest for MRI (293,362) and mammography (151,664). Twenty-seven percent of videos used a nontraditional format (eg, animation, song, humor). All videos (100.0%) depicted a patient undergoing the examination, 84.1% a technologist, and 20.6% a radiologist; 69.8% mentioned examination lengths, 65.1% potential pain/discomfort, 41.3% potential radiation, 36.5% a radiology report/results, 27.0% the radiologist's role in interpretation, and 13.3% laboratory work. For CT, 68.8% mentioned intravenous contrast and 37.5% mentioned contrast safety. For MRI, 93.8% mentioned claustrophobia, 87.5% noise, 75.0% need to sit still, 68.8% metal safety, 50.0% intravenous contrast, and 0.0% contrast safety. For ultrasound, 85.7% mentioned use of gel. For PET, 92.3% mentioned radiotracer injection, 61.5% fasting, and 46.2% diabetic precautions. For mammography, unrobing, avoiding deodorant, and possible additional images were all mentioned by 63.6%; dense breasts were mentioned by 0.0%. Educational patient videos on YouTube regarding common imaging examinations received high public interest and may provide a valuable patient resource. Videos most consistently provided information detailing the examination experience and less consistently provided safety information or described the presence and role of the radiologist. Copyright © 2016 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  2. Emission of ammonia from indoor concrete wall and assessment of human exposure.

    Science.gov (United States)

    Bai, Z; Dong, Y; Wang, Z; Zhu, T

    2006-04-01

    Addition of urea-based antifreeze admixtures during cement mixing can make it possible to produce concrete cement in construction of buildings in cold weather; this, however, has led to increasing indoor air pollution due to continuous transformation and emission from urea to gaseous ammonia in indoor concrete wall. It is believed that ammonia is harmful to human body and exposure to ammonia can cause some serious symptoms such as headaches, burns, and even permanent damage to the eyes and lungs. In order to understand the emission of ammonia from indoor concrete wall in civil building and assess the health risk of people living in these buildings, the experimental pieces of concrete wall were first prepared by concreting cement and urea-based antifreeze admixtures to simulate the indoor wall in civil building in this work. Then environmental chamber was adopted for studying the effect of temperature, relative humility and air exchange rate on emission of ammonia from experimental pieces of concrete wall. Also the field experiment was made at selected rooms in given civil buildings. Exposure and potential dose of adult and children exposed to indoor/outdoor ammonia in summer and in winter are calculated and evaluated by using Scenario Evaluation Approach. The results indicated that high air exchange rate leads to decreased ammonia concentration, and elevation of temperature causes increasing ammonia concentration and volatilizing rate in chamber. The complete emission of ammonia from the wall containing urea-based antifreeze admixtures needs more than 10 years in general. Ventilating or improving air exchange can play a significant role in reducing ammonia concentration in actual rooms in field experiments. Urea-based antifreeze admixtures in concrete wall can give rise to high exposure and potential dose, especially in summer. Generally, adults have a high potential dose than children, while children have personal average dose rate beyond adults in the same

  3. Technique for joining metal tubing

    Science.gov (United States)

    Wright, H. W.

    1976-01-01

    Uniform wall thickness and uninterrupted heat transfer is achieved by using shaped metal insert as wall material for joint. Insert acts as support during brazing, after which excess material is ground away to bring joint to original tubing size.

  4. Reliability assessment for thickness measurements of pipe wall using probability of detection

    International Nuclear Information System (INIS)

    Nakamoto, Hiroyuki; Kojima, Fumio; Kato, Sho

    2013-01-01

    This paper proposes a reliability assessment method for thickness measurements of pipe wall using probability of detection (POD). Thicknesses of pipes are measured by qualified inspectors with ultrasonic thickness gauges. The inspection results are affected by human factors of the inspectors and include some errors, because the inspectors have different experiences and frequency of inspections. In order to ensure reliability for inspection results, first, POD evaluates experimental results of pipe-wall thickness inspection. We verify that the results have differences depending on inspectors including qualified inspectors. Second, two human factors that affect POD are indicated. Finally, it is confirmed that POD can identify the human factors and ensure reliability for pipe-wall thickness inspections. (author)

  5. WWER steam generator tube structural and leakage integrity

    International Nuclear Information System (INIS)

    Splichal, K.; Krhounek, Vl.; Otruba, J.; Ruscak, M.

    1998-01-01

    The integrity of heat exchange tubes may influence the lifetime of WWER steam generators and appears to be an important criterion for the evaluation of their safety and operational reliability. The basic requirements are to assure very low probability of radioactive water leakage, preventing unstable crack growth and sudden tube rupture. These requirements led to development of permissible limits for primary to secondary leak evaluation and heat exchange tubes plugging. The stress corrosion cracking and pitting are the main corrosion damages of WWER heat exchange tubes and are initiated from the outer surface. Both the initiation and crack growth cause thinning of the tube wall and lead to part thickness cracks and through wall cracks, oriented preferentially in the axial direction. The paper presents the leakage and plugging limits for WWER steam generators, which have been determined from leak tests and burst tests. The tubes with axial part-through and through-wall defects have been used. The permissible value of primary to secondary leak rate was evaluated with respect to permissible axial through-wall defect size of WWER 440 and 1000 steam generator tubes. Blocking of the tube cracks by corrosion product particles and other compounds reduces the primary to secondary leak rate. The plugging limits involve the following factors: permissible tube wall thickness which determine further operation of the tubes with defects and assures their integrity under operating conditions and permissible size of a through-wall crack which is sufficiently stable under normal and accident conditions in relation to the critical crack length. For the evaluation of burst test of heat exchange tubes with longitudinal through-wall defects the instability criterion has been used and the dependence of the normalised burst pressure on the normalised length of an axial through-wall defect has been determined. The validity of the criterion of instability for WWER tubes with through-wall

  6. Development and preliminary assessment of the wall condensation heat transfer models for the SPACE code

    International Nuclear Information System (INIS)

    Park, Hyun Sik; Choi, Ki Yong; Moon, Sang Ki; Kim, Jung Woo; Kim, Kyung Doo

    2009-01-01

    The wall condensation heat transfer models are developed for the SPACE code and are assessed for various condensation conditions. Both default and alternative models were selected through an extensive literature survey. For a pure steam condensation, a maximum value among the Nusselt, Chato, and Shah's correlations is used in order to consider the geometric and turbulent effects. In the presence of non-condensable gases, the Colburn-Hougen's diffusion model was used as a default model and a non-iterative condensation model proposed by No and Park was selected as an alternative model. The wall condensation heat transfer models were assessed preliminarily by using arbitrary test conditions. Both wall condensation models could simulate the heat transfer coefficients and heat fluxes in the vertical, horizontal and turbulent conditions quite reasonably for a pure steam condensation. Both the default and alternative wall condensation models were also verified for the condensation heat transfer coefficient and heat flux in the presence of noncondensable gas. However, some improvements and further detailed verification are necessary for the condensation phenomena in the presence of noncondensable gas

  7. Damage assessment for seismic response of recycled concrete filled steel tube columns

    Science.gov (United States)

    Huang, Yijie; Xiao, Jianzhuang; Shen, Luming

    2016-09-01

    A model for evaluating structural damage of recycled aggregate concrete filled steel tube (RCFST) columns under seismic effects is proposed in this paper. The proposed model takes the lateral deformation and the effect of repeated cyclic loading into account. Available test results were collected and utilized to calibrate the parameters of the proposed model. A seismic test for six RCFST columns was also performed to validate the proposed damage assessment model. The main test parameters were the recycled coarse aggregate (RCA) replacement percentage and the bond-slip property. The test results indicated that the seismic performance of the RCFST member depends on the RCA contents and their damage index increases as the RCA replacement percentage increases. It is also indicated that the damage degree of RCFST changes with the variation of the RCA replacement percentage. Finally, comparisons between the RCA contents, lateral deformation ratio and damage degree were implemented. It is suggested that an improvement procedure should be implemented in order to compensate for the performance difference between the RCFST and normal concrete filled steel tubes (CFST).

  8. Assessment of the integrity of degraded steam generator tube by the use of heterogeneous finite element method

    International Nuclear Information System (INIS)

    Duan, X.; Kozluk, M.; Pagan, S.; Mills, B.

    2006-01-01

    Steam generator tubes at Ontario Power Generation (OPG) have been experiencing a variety of degradations such as pitting, fretting wear, erosion-corrosion, thinning and denting. To assist with steam generator life cycle management, OPG has developed Fitness-For-Service Guidelines (FFSG) for steam generator tubes. The FFSG are intended to provide standard acceptance criteria and evaluation procedures for assessing the condition of steam generator tubes for structural integrity, operational leak rate, and consequential leakage during an upset or abnormal event. Based on inspection results in conjunction with representative, postulated distributions of flaws in the un-inspected tubes, the FFSG provide an acceptable method of satisfying the intent of CSA-N285.4 and justifying the continued operation of degraded steam generator tubes. Some non-mandatory empirical axial and circumferential flaw models are also provided in the FFSG for structural integrity assessments. The test data from the OPG Steam Generator Tube Test Program (SGTTP) showed that the FFSG axial flaw model is conservative for a wide range of defect morphologies. A defect-specific axial flaw model was proposed for lattice-bar fret defects in I800 tubes by utilizing the SGTTP database of extensive test results. A defect-specific flaw model for outer diameter (OD) pitting and inner diameter (ID) intergranular attack in Monel 400 tubes was also developed using the SGTTP test data. More tests have been scheduled to support the development of defect specific models for axial flaws (OD cracks or ID laps) in Monel 400 and to supplement the database for Monel 400 pits. This paper explores the use of simulated testing for use in developing defect specific flaw models to reduce the amount of expensive tests. The Heterogeneous Finite Element Model (HFEM) has been developed and successfully applied to predict the failure behaviour of ductile metals under various deformation modes, i.e. plane stress, plane strain and

  9. An assessment of prediction methods of CHF in tubes with a large experimental data bank

    International Nuclear Information System (INIS)

    Leung, L.K.H.; Groeneveld, D.C.

    1993-01-01

    An assessment of prediction methods of CHF in tubes has been carried out using an expanded CHF data bank at Chalk River Laboratories (CRL). It includes eight different CHF look-up tables (two AECL versions and six USSR (or Russian) versions) and three empirical correlations. These prediction methods were developed from relatively large data bases and therefore have a wide range of application. Some limitations, however, were imposed in this study, to avoid any invalid predictions due to extrapolation of these methods. Therefore, these comparisons are limited to the specific data base that is tailored to suit the range of an individual method. This has resulted in a different number of data used in each case. The comparison of predictions against the experimental data is based on the constant inlet-condition approach (i.e., the pressure, mass flux, inlet fluid temperature and tube geometry are the primary parameters). Overall, the AECL tables have the widest range of application. They are assessed with 21 771 data points and the root-mean-square error is only 8.3%. About 60% of these data were used in the development of the AECL tables. The best version of the USSR/Russian CHF table is valid for 13 300 data points with a root-mean-square error of 8.8%. The USSR/Russian table that has the widest range of application covers a total of 18 800 data points, but the error increases to 9.3%. The range of application for empirical correlations, however, are generally much narrower than those covered by the CHF tables. The number of data used to assess these correlations is therefore further limited. Among the tested correlations, the Becker and Persson correlation covers the least amount of data (only 7 499 data points), but has the best accuracy (with a root-mean-square error of 9.71%). 33 refs., 2 figs., 3 tabs

  10. Ultrasonic measurements for in-service assessment of wrought Inconel 625 cracker tubes of heavy water plants

    International Nuclear Information System (INIS)

    Kumar, Anish; Rajkumar, K.V.; Jayakumar, T.; Raj, Baldev; Mishra, B.

    2006-01-01

    The degradation in mechanical properties of Inconel 625 ammonia cracker tubes occurs during the service for long duration in heavy water plants. The present study brings out the possibility of using Poisson's ratio (derived from measurement of time of flight of ultrasonic waves) in combination with hardness measurements, as an effective non-destructive tool for assessment of in-service degradation of Inconel 625 cracker tubes and qualification of re-solution annealing heat treatment for their rejuvenation. Further, the study also indicates the feasibility of extending the life of some of the tubes beyond the presently followed 120 000 h, before they are taken up for re-solution annealing, without affecting their serviceability. However, further studies are required to identify quantitative criterion for Poisson's ratio and hardness values, for deciding on the basis for removal of the tubes for rejuvenation

  11. Fabrication of seamless calandria tubes

    International Nuclear Information System (INIS)

    Saibaba, N.; Phanibabu, C.; Bhaskara Rao, C.V.; Kalidas, R.; Ganguly, C.

    2002-01-01

    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 f r 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

  12. Uncertainty assessment of a dike with an anchored sheet pile wall using FEM

    Directory of Open Access Journals (Sweden)

    Rippi Aikaterini

    2016-01-01

    Full Text Available The Dutch design codes for the dikes with retaining walls rely on Finite Element Analysis (FEM in combination with partial safety factors. However, this can lead to conservative designs. For this reason, in this study, a reliability analysis is carried out with FEM calculations aiming to demonstrate the feasibility of reliability analysis for a dike with an anchored sheet pile wall modelled in the 2D FEM, Plaxis. Sensitivity and reliability analyses were carried out and enabled by coupling the uncertainty package, OpenTURNS and Plaxis. The most relevant (ultimate limit states concern the anchor, the sheet pile wall, the soil body failure (global instability and finally the system. The case was used to investigate the applicability of the First Order Reliability Method (FORM and Directional Sampling (DS to analysing these limit states. The final goal is to estimate the probability of failure and identify the most important soil properties that affect the behaviour of each component and the system as a whole. The results of this research can be used to assess and optimize the current design procedure for dikes with retaining walls.

  13. Extraction of Vertical Walls from Mobile Laser Scanning Data for Solar Potential Assessment

    Directory of Open Access Journals (Sweden)

    Martin Rutzinger

    2011-03-01

    Full Text Available In recent years there has been an increasing demand among home owners for cost effective sustainable energy production such as solar energy to provide heating and electricity. A lot of research has focused on the assessment of the incoming solar radiation on roof planes acquired by, e.g., Airborne Laser Scanning (ALS. However, solar panels can also be mounted on building facades in order to increase renewable energy supply. Due to limited reflections of points from vertical walls, ALS data is not suitable to perform solar potential assessment of vertical building facades. This paper focuses on a new method for automatic solar radiation modeling of facades acquired by Mobile Laser Scanning (MLS and uses the full 3D information of the point cloud for both the extraction of vertical walls covered by the survey and solar potential analysis. Furthermore, a new method isintroduced determining the interior and exterior face, respectively, of each detected wall in order to calculate its slope and aspect angles that are of crucial importance for solar potential assessment. Shadowing effects of nearby objects are considered by computing the 3D horizon of each point of a facade segment within the 3D point cloud.

  14. An assessment of the waterside corrosion and hydrogen pick-up in the zircaloy-2 pressure tubes of PHWR

    International Nuclear Information System (INIS)

    Sah, D.N.

    1992-01-01

    In view of the deleterious effect of hydriding on the operating life of zircaloy-2 pressure tubes in PHWRs there is an urgent need for the assessment of the status of the pressure tubes with respect to corrosion and hydrogen pick-up in the operating PHWRs. A model has been developed for analysing the waterside corrosion and hydrogen pick-up in the zircaloy-2 pressure tubes under reactor operating conditions. This model predicts the axial profiles of oxide layer thickness and hydrogen pick-up in the pressure tubes as a function of the operating time of the reactor. The prediction of hydrogen pick-up by the model in the F-10 pressure tube of RAPS-I have been found to be in good agreement with the measured value of hydrogen content. This report gives a brief description of the model and its predictions on the present status of hydrogen pick-up in the pressure tubes of lead reactor RAPS-II. (author). 6 refs., 5 figs., 2 tabs

  15. Folate status in women of reproductive age as basis of neural tube defect risk assessment.

    Science.gov (United States)

    Bailey, Lynn B; Hausman, Dorothy B

    2018-02-01

    Reliable folate status data for women of reproductive age (WRA) to assess global risk for neural tube defects (NTDs) are needed. We focus on a recent recommendation by the World Health Organization that a specific "optimal" red blood cell (RBC) folate concentration be used as the sole indicator of NTD risk within a population and discuss how to best apply this guidance to reach the goal of assessing NTD risk globally. We also emphasize the importance of using the microbiologic assay (MBA) as the most reliable assay for obtaining comparable results for RBC folate concentration across time and countries, the need for harmonization of the MBA through use of consistent key reagents and procedures within laboratories, and the requirement to apply assay-matched cutoffs for folate deficiency and insufficiency. To estimate NTD risk globally, the ideal scenario would be to have country-specific population-based surveys of RBC folate in WRA determined utilizing a harmonized MBA, as was done in recent studies in Guatemala and Belize. We conclude with guidance on next steps to best navigate the road map toward the goal of generating reliable folate status data on which to assess NTD risk in WRA in low- and middle-income countries. © 2017 The Authors. Annals of the New York Academy of Sciences published by Wiley Periodicals, Inc. on behalf of New York Academy of Sciences.

  16. Novel device (AirWave) to assess endotracheal tube migration: a pilot study.

    Science.gov (United States)

    Nacheli, Gustavo Cumbo; Sharma, Manish; Wang, Xiaofeng; Gupta, Amit; Guzman, Jorge A; Tonelli, Adriano R

    2013-08-01

    Little is known about endotracheal tube (ETT) migration during routine care among critically ill patients. AirWave is a novel device that uses sonar waves to measure ETT migration and obstructions in real time. The aim of the present study is to assess the accuracy of the AirWave to evaluate ETT migration. In addition, we determined the degree of variation in ETT position and tested whether more pronounced migration occurs in specific clinical scenarios. After institutional review board approval, we included mechanically ventilated patients from February 2012 to May 2012. A chest radiography (CXR) was obtained at baseline and 24 hours when clinically indicated. The ETT distance at the lips was recorded at baseline and every 4 hours. The AirWave system continuously recorded ETT position changes from baseline, and luminal obstructions. A total of 42 patients (age: 61 [SD ±13] years, men: 52%) were recruited. A total of 19 patients had measurements of ETT migration at 24 hours by the 3 methodologies used in this study. The mean (SD) of the ETT migration at 24 hours was +0.04 (1.2), -0.42 (0.7) and +0.34 (1.81) cm when measured by portable CXR, ETT distance at the teeth and AirWave device, respectively. Bland-Altman analysis of tube migration at 24 hours comparing the AirWave with CXR readings showed a bias of 0.1 cm with 95% limit of agreement of -3.8 and +4.3 cm. Comparison of tube migration at 24 hours determined by AirWave with ETT distance at the lips revealed a bias of -0.4 with 95% limit of agreement -3.7 to +3 cm, similar to the values observed between CXR and ETT distance at the lips (bias of -0.3 cm, 95% limit of agreement of -3.4 to +2.8 cm). Factors associated with ETT migration at 24 hours were ETT size and initial measurement from ETT tip to carina by portable CXR. AirWave detected in eight patients some degree of ETT obstruction (30% ± 9.6%) that resolved with prompt ETT catheter suction. The AirWave may provide useful information regarding ETT

  17. Methodologies for assessment of the service life of pressure tubes in Indian PHWRs

    International Nuclear Information System (INIS)

    Sinha, R.K.; Sharma, A.; Madhusoodanan, K.; Sinha, S.K.; Malshe, U.D.

    1997-01-01

    For estimating safe service life of pressure tubes in Indian PHWRs, analytical methodologies have been developed to evaluate creep deformation, deuterium pick-up rate, blister growth at cold spot, and operating domain required for achieving leak-before-break. The paper provides an overview of these methodologies, and results of some studies carried out towards evolution of proposed fitness-for-service criteria for a pressure tube in contact with its calandria tube. (author)

  18. Qualitative assessment of precocious puberty-related user-created contents on YouTube

    Directory of Open Access Journals (Sweden)

    Hyo-Kyoung Nam

    2015-09-01

    Full Text Available PurposeUser-created content (UCC has provided a considerable amount of medical information and become an important source. We aimed to evaluate the quality and scientific accuracy of precocious puberty-related UCC on YouTube.MethodsThe keywords "precocious puberty", "early puberty", "sexual precocity", and "precocity" were searched for on YouTube during June and July 2014. More than 1,500 UCC matched the keywords. According to the information provider, UCC was classified as medical, oriental, or commercial & others. We evaluated the quality and scientific accuracy of the information provided in UCC using the DISCERN instrument and information scores, respectively.ResultsWe selected 51 UCC, which were categorized into three types: medical (n=17, oriental (n=17, or commercial & others (n=17. The overall quality score for medical UCC (3.4 was significantly higher relative to those of oriental and commercial & others UCC (2.8 and 2.3, respectively (P<0.001. In the assessment of scientific accuracy, the mean information score for medical UCC (30.7 was significantly higher than those of oriental and commercial & others UCC (15.9 and 5.1, respectively (P<0.001. The mean duration of oriental UCC was the longest (P<0.001, however, it was viewed less frequently among them (P=0.086.ConclusionThe quality and accuracy of precocious puberty-related health information in UCC were variable and often unreliable. The overall quality of UCC regarding precocious puberty was moderate. Only medical UCC provided scientifically accurate information. As UCC becomes a popular source of health information, it is important to provide reliable, scientifically accurate information.

  19. Assessment of "YouTube" Content for Distal Radius Fracture Immobilization.

    Science.gov (United States)

    Addar, Abdullah; Marwan, Yousef; Algarni, Nizar; Berry, Gregory

    Distal radius fractures (DRFs) are the most common orthopedic fractures, with >70% of cases treated by closed immobilization using a short arm cast or a sugar tong splint. However, inadequate immobilization is a risk factor for loss of reduction requiring repeat reduction or surgical treatment. Therefore, education of clinical skills for appropriate immobilization of DRFs is important. With the increasing use of web-based information by medical learners, our aim was to assess the quality and quantity of videos regarding closed immobilization of DRFs on YouTube. Retrospective review of YouTube videos on distal radius fracture immobilization using specific search terms. Identified videos were analyzed for their educational value, quality of the technical skill demonstrated, and overall metrics. Educational value was scored on a 5-point scale, with "1" indicative of low quality and "5" of high quality. Not applicable. Among the 68,366 videos identified, 16 met our inclusion criteria of being in English; performed by a health care professional or institution; and with casting being the major theme of the educational information provided. Of these 16 videos, 6 had an educational value score of 4 or 5, with the remaining 10 having a score ≤3. Although immobilization was demonstrated by cast technician specialized in orthopedics, skills were also performed by orthopedic attendants, urgent care physicians, orthopedic residents, and nurse practitioners. The credentials of the performer in 3 videos were not identified. There is a need to promote high-quality educational videos produced by established medical school faculty members on open, web-based, portals. Copyright © 2017 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

  20. Isometric abdominal wall muscle strength assessment in individuals with incisional hernia: a prospective reliability study

    DEFF Research Database (Denmark)

    Jensen, K. K.; Kjær, Michael; Jorgensen, L. N.

    2016-01-01

    Purpose To determine the reliability of measurements obtained by the Good Strength dynamometer, determining isometric abdominal wall and back muscle strength in patients with ventral incisional hernia (VIH) and healthy volunteers with an intact abdominal wall. Methods Ten patients with VIH and ten...... and extension showed excellent test–retest reliability for both patients with VIH (ICC 0.91 and 0.99) and healthy controls (ICC 0.97 and 0.96). Bland and Altman plots showed that no systematic bias was present for neither truncal flexion nor extension when assessing reliability. For patients with VIH...... and IPAQ was found. Conclusions The Good Strength dynamometer provided a reliable, low-cost measure of truncal flexion and extension in patients with VIH....

  1. Guide tube sleeve

    International Nuclear Information System (INIS)

    Attix, D.J.

    1983-01-01

    The invention increases the operating capacity of a nuclear reactor by causing a modification in the flow pattern of the coolant which enhances the coolant's effectiveness. The apparatus provides a thin-walled tubular sleeve closely surrounding but not attached to the exterior surface of a guide tube in a fuel assembly. The wall of the sleeve has tabs projecting outwardly into adjacent flow channels. The sleeve is attached to the wall of a cellular void through which passes the guide tube associated with said sleeve. The tabs increase the flow of water in the channel and thus increase the heat transfer

  2. Isometric abdominal wall muscle strength assessment in individuals with incisional hernia: a prospective reliability study.

    Science.gov (United States)

    Jensen, K K; Kjaer, M; Jorgensen, L N

    2016-12-01

    To determine the reliability of measurements obtained by the Good Strength dynamometer, determining isometric abdominal wall and back muscle strength in patients with ventral incisional hernia (VIH) and healthy volunteers with an intact abdominal wall. Ten patients with VIH and ten healthy volunteers with an intact abdominal wall were each examined twice with a 1 week interval. Examination included the assessment of truncal flexion and extension as measured with the Good Strength dynamometer, the completion of the International Physical Activity Questionnaire (IPAQ) and the self-assessment of truncal strength on a visual analogue scale (SATS). The test-retest reliability of truncal flexion and extension was assessed by interclass correlation coefficient (ICC), and Bland and Altman graphs. Finally, correlations between truncal strength, and IPAQ and SATS were examined. Truncal flexion and extension showed excellent test-retest reliability for both patients with VIH (ICC 0.91 and 0.99) and healthy controls (ICC 0.97 and 0.96). Bland and Altman plots showed that no systematic bias was present for neither truncal flexion nor extension when assessing reliability. For patients with VIH, no significant correlations between objective measures of truncal strength and IPAQ or SATS were found. For healthy controls, both truncal flexion (τ 0.58, p = 0.025) and extension (τ 0.58, p = 0.025) correlated significantly with SATS, while no other significant correlation between truncal strength measures and IPAQ was found. The Good Strength dynamometer provided a reliable, low-cost measure of truncal flexion and extension in patients with VIH.

  3. MDCT assessment of airway wall thickness in COPD patients using a new method: correlations with pulmonary function tests

    International Nuclear Information System (INIS)

    Achenbach, Tobias; Weinheimer, Oliver; Schmitt, Sabine; Freudenstein, Daniela; Kunz, Richard Peter; Dueber, Christoph; Biedermann, Alexander; Buhl, Roland; Goutham, Edula; Heussel, Claus Peter

    2008-01-01

    Quantitative assessment of airway-wall dimensions by computed tomography (CT) has proven to be a marker of airway-wall remodelling in chronic obstructive pulmonary disease (COPD) patients. The objective was to correlate the wall thickness of large and small airways with functional parameters of airflow obstruction in COPD patients on multi-detector (MD) CT images using a new quantification procedure from a three-dimensional (3D) approach of the bronchial tree. In 31 patients (smokers/COPD, non-smokers/controls), we quantitatively assessed contiguous MDCT cross-sections reconstructed orthogonally along the airway axis, taking the point-spread function into account to circumvent over-estimation. Wall thickness and wall percentage were measured and the per-patient mean/median correlated with FEV1 and FEV1%. A median of 619 orthogonal airway locations was assessed per patient. Mean wall percentage/mean wall thickness/median wall thickness in non-smokers (29.6%/0.69 mm/0.37 mm) was significantly different from the COPD group (38.9%/0.83 mm/0.54 mm). Correlation coefficients (r) between FEV1 or FEV1% predicted and intra-individual means of the wall percentage were -0.569 and -0.560, respectively, with p<0.001. Depending on the parameter, they were increased for airways of 4 mm and smaller in total diameter, being -0.621 (FEV1) and -0.537 (FEV1%) with p < 0.002. The wall thickness was significantly higher in smokers than in non-smokers. In COPD patients, the wall thickness measured as a mean for a given patient correlated with the values of FEV1 and FEV1% predicted. Correlation with FEV1 was higher when only small airways were considered. (orig.)

  4. Failure probability assessment of wall-thinned nuclear pipes using probabilistic fracture mechanics

    International Nuclear Information System (INIS)

    Lee, Sang-Min; Chang, Yoon-Suk; Choi, Jae-Boong; Kim, Young-Jin

    2006-01-01

    The integrity of nuclear piping system has to be maintained during operation. In order to maintain the integrity, reliable assessment procedures including fracture mechanics analysis, etc., are required. Up to now, this has been performed using conventional deterministic approaches even though there are many uncertainties to hinder a rational evaluation. In this respect, probabilistic approaches are considered as an appropriate method for piping system evaluation. The objectives of this paper are to estimate the failure probabilities of wall-thinned pipes in nuclear secondary systems and to propose limited operating conditions under different types of loadings. To do this, a probabilistic assessment program using reliability index and simulation techniques was developed and applied to evaluate failure probabilities of wall-thinned pipes subjected to internal pressure, bending moment and combined loading of them. The sensitivity analysis results as well as prototypal integrity assessment results showed a promising applicability of the probabilistic assessment program, necessity of practical evaluation reflecting combined loading condition and operation considering limited condition

  5. Trypan blue to assess Baerveldt tube patency after repair of its obstruction.

    Science.gov (United States)

    Grigg, John; Jang, John D W; Fung, Adrian T; Hunyor, Alex P; Wilson, Trevor

    2011-12-01

    Tubal obstruction is a recognized complication of glaucoma drainage implants. In correcting a blocked tube, the surgeon may be uncertain about shunt competence even after removing the suspected cause of obstruction. We report the use of trypan blue dye to show tubal patency directly after the repair of a blocked Baerveldt tube.

  6. Pressure tests to assess the significance of defects in boiler and superheater tubing

    International Nuclear Information System (INIS)

    Guest, J.C.; Hutchings, J.A.

    1975-01-01

    Internal pressure tests on 9 per cent Cr-1 per cent Mo steel tubing containing artificial defects demonstrated that the resultant loss of strength was less than a simple calculation based on the reduced tube thickness would suggest. Bursting tests on tubes containing longitudinal defects of varying length, depth and acuity showed notch strengthening at ambient temperature and at 550 0 C. A flow stress concept developed for simple bursting tests was shown to apply to creep conditions at 550 0 C. Results of creep and short-term bursting tests show that the length as well as the depth of the defect is an important factor affecting the life of bursting strength of the tubes. Defects less than 10 per cent of the tube thickness were found to have an insignificant effect. (author)

  7. Methodology for failure assessment of SMART SG tube with once-through helical-coiled type

    International Nuclear Information System (INIS)

    Kim, Young Jin; Choi, Shin Beom; Cho, Doo Ho; Chang, Yoon Suk

    2010-09-01

    In this research project, existing integrity evaluation method for SMART steam generator tube with crack-like flaw was reviewed to determine subject analysis model and investigate possibility of failure under crack closure behavior. Furthermore, failure pressure estimation was proposed for SMART steam generator tubes containing wear-type defects. For each subject, the following issues are addressed: 1. Determination of subject analysis model for SMART SG tube contaning crack-like flaw 2. Applicability review on existing integrity evaluation method and investigation of failure possibility for SMART SG tube containing crack-like flaw 3. Development of failure pressure estimation model for SMART SG tube with wear type defect It is anticipated that if the technologies developed in this study are applied, structural integrity can be estimated accurately

  8. Development and validation of an elastic and inelastic calculation method for tubes, based on beam models and taking into account the thermal stresses on the wall

    International Nuclear Information System (INIS)

    Krakowiak, C.

    1989-11-01

    A simplified model for the elastic-plastic calculations of thin and flexible tubes submitted to thermal stresses is presented. The method is based on beam models and provides satisfactory results concerning the displacement of the whole tube system. These results can be justified by the fact that the modifications of the tube cross sections (from circular to elliptical), the flexibility of the elbow joints and the radial temperature profile are included in the calculations. The thermoplasticity analysis is performed by defining independent and general flow directions and determining the corresponding behavior laws. The model is limited to proportional monotonous charging, however the obtained results are promissing [fr

  9. Assessment of posterior vaginal wall prolapse: comparison of physical findings to cystodefecoperitoneography.

    Science.gov (United States)

    Altman, Daniel; López, Annika; Kierkegaard, Jonas; Zetterström, Jan; Falconer, Christian; Pollack, Johan; Mellgren, Anders

    2005-01-01

    The aim of the present study was to compare clinical and radiological findings when assessing posterior vaginal wall prolapse. Defecography can be used to complement the clinical evaluation in patients with posterior vaginal wall prolapse. Further development of the defecography technique, using contrast medium in the urinary bladder and intraperitoneally, have resulted in cystodefecoperitoneography (CDP). Thirty-eight women underwent clinical examination using the pelvic organ prolapse quantification system (POP-Q) followed by CDP. All patients answered a standardized bowel function questionnaire. Statistical analysis measuring correlation between POP-Q and CDP using Pearson's correlation coefficient (r) and Spearman's rank order correlation coefficient (rs) demonstrated a poor to moderate correlation, r=0.49 and rs=0.55. Although there was a strong association between large rectoceles (>3 cm) at CDP and symptoms of rectal emptying difficulties (p<0.001), severity and prevalence of bowel dysfunction showed poor coherence with clinical prolapse staging and findings at radiological imaging. Vaginal topography and POP-Q staging predict neither radiological size nor visceral involvement in posterior vaginal wall prolapse. Radiological evaluation may therefore be a useful complement in selected patients.

  10. Assessment of the impact that the capsule fill tube has on implosions conducted with high density carbon ablators

    Science.gov (United States)

    Pak, Arthur; Benedetti, L. R.; Berzak Hopkins, L. F.; Clark, D.; Divol, L.; Dewald, E. L.; Fittinghoff, D.; Izumi, N.; Khan, S. F.; Landen, O.; Lepape, S.; Ma, T.; Marley, E.; Nagel, S.; Volegov, P.; Weber, C.; Bradley, D. K.; Callahan, D.; Grim, G.; Hurricane, O. A.; Patel, P.; Schneider, M. B.; Edwards, M. J.

    2017-10-01

    In recent inertial confinement implosion experiments conducted at the National Ignition Facility, bright and spatially localized x-ray emission within the hot spot at stagnation has been observed. This emission is associated with higher Z ablator material that is injected into the hot spot by the hydrodynamic perturbation induced by the 5-10 um diameter capsule fill tube. The reactivity of the DT fuel and subsequent yield of the implosion are strongly dependent on the density, temperature, and confinement time achieved throughout the stagnation of the implosion. Radiative losses from higher Z ablator material that mixes into the hot spot as well as non-uniformities in the compression and confinement induced by the fill tube perturbation can degrade the yield of the implosion. This work will examine the impact to conditions at stagnation that results from the fill tube perturbation. This assessment will be based from a pair of experiments conducted with a high density carbon ablator where the only deliberate change was reduction in fill tube diameter from 10 to 5 um. An estimate of the radiative losses and impact on performance from ablator mix injected into the hot spot by the fill tube perturbation will be presented. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  11. Probabilistic methodology for assessing steam generator tube inspection - Phase II: User's manual for CANTIA Version 1.1

    International Nuclear Information System (INIS)

    Harris, J.E.; Gorman, J.A.; Turner, A.P.L.

    1997-03-01

    The objectives of this project were to develop a computer-based method for probabilistic assessment of inspection strategies for steam generator tubes, and to document the source code and to provide a user's manual for it. The program CANTIA was created to fulfill this objective, and the user's manual is provided in this volume. The documentation and verification of the CANTIA code is provided as a separate report. CANTIA uses Monte Carlo techniques to determine approximate probabilities of steam generator tube failures under accident conditions and primary-to-secondary leak rates under normal and accident conditions at future points in time. The program also determines approximate future flaw distributions and non-destructive examination results from the input data. The probabilities of failure and leak rates and the future flaw distributions can be influenced by performing inspections of the steam generator tubes at some future points in time, and removing defective tubes from the population. The effect of different inspection and maintenance strategies can therefore be determined as a direct effect on the probability of tube failure and primary-to-secondary leak rate

  12. Some Observations on Carbon Nano tubes Susceptibility to Cell Phagocytosis

    International Nuclear Information System (INIS)

    Fraczek-Szczypta, A.; Menaszek, E.; Blazewicz, S.; Menaszek, E.

    2011-01-01

    The aim of this study was to assess the influence of different types of carbon nano tubes (CNTs) on cell phagocytosis. Three kinds of carbon nano tubes: single-walled carbon nano horns (SWCNHs), multi walled carbon nano tubes (MWCNTs), and ultra-long single-walled carbon nano tubes (ULSWCNTs) before and after additional chemical functionalization were seeded with macrophage cell culture. Prior to biological testing, the CNTs were subjected to dispersion process with the use of phosphate buffered solution (PBS) and PBS containing surfactant (Tween 20) or dimethyl sulfoxide (DMSO). The results indicate that the cells interaction with an individual nano tube is entirely different as compared to CNTs in the form of aggregate. The presence of the surfactant favors the CNTs dispersion in culture media and facilitates phagocytosis process, while it has disadvantageous influence on cells morphology. The cells phagocytosis is a more effective for MWCNTs and SWCNHs after their chemical functionalization. Moreover, these nano tubes were well dispersed in culture media without using DMSO or surfactant. The functionalized carbon nano tubes were easily dispersed in pure PBS and seeded with cells

  13. Assessment Using ANL Experiments on Void Fraction in a Vertical Tube

    Energy Technology Data Exchange (ETDEWEB)

    Han, KyuHyun; Bang, YoungSeok [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2015-05-15

    A licensing application of a safety analysis code, SPACE, was submitted and is currently under KINS' review. This code was developed to consider three fluid fields, i.e. liquid, vapor and droplet, for a realistic simulation of accident phenomena. Therefore, there may be a concern that this code could predict different behavior compared to the existing codes. To assess the important performance independently and to compare with prediction results of SPACE might be helpful to regulatory review for identifying validity of the code. The interfacial friction could largely affect prediction of thermal hydraulic phenomena during LOCA or non- LOCA. This paper provides MARS-KS prediction of void fraction experiments in a vertical tube by ANL and compares with SPACE prediction results. It was found that the similar interfacial friction model adopting the drift flux correlations were implemented in both codes. Experimental void fractions of the ANL test presented in this paper correspond to bubbly, slug and churn flow regions. Agreements in general sense between the experiment and the predicted values were identified through calculations. Thus, similar accuracy for this experiment can be expected in SPACE and MARS-KS. It was also shown that drift flux interfacial friction model for intermediate flow channel (diameter of 7cm) is valid.

  14. Use of CATHENA to model calandria-tube/moderator heat transfer after pressure-tube/calandria-tube ballooning contact

    International Nuclear Information System (INIS)

    Fan, H.Z.; Bilanovic, Z.; Nitheanandan, T.

    2004-01-01

    A study was performed to assess the effect of the calandria-tube/moderator heat transfer after pressure-tube/calandria tube ballooning contact using CATHENA. Results of this study indicated that the analytical tool, CATHENA, can be applied for pool boiling heat transfer on the external surface of a large diameter tube, such as the calandria tube used in CANDU reactors. The methodology in such CANDU-generic study can be used to simulate the tube surface with multiple boiling regimes and to assess the benefits of closely coupling thermalhydraulics modelling and fuel/fuel channel behaviour modelling. CATHENA (Canadian Algorithm for THErmalhydraulic Network Analysis) is a one-dimensional, two-fluid thermalhydraulic simulation code designed by AECL to analyse two-phase flow and heat transfer in piping networks. The detailed heat transfer package in CATHENA allows a connection to be established from the multiple solid surfaces of tubes to the surrounding large amount of moderator water, which acts as a heat sink during a postulated loss of coolant event. The generalized heat transfer package within CATHENA allows the tube walls to be divided into several layers in the radial direction and several sectors in the circumferential direction, to account for heat transfer conditions in these two directions. The CATHENA code with the generalized heat transfer package is capable of capturing key pool-boiling phenomena such as nucleate, transition and film boiling heat transfer as well as an ability to model the rewet phenomenon to some extent. A CATHENA input model was generated and used in simulations of selected contact boiling experiment test cases. The transient wall temperatures have been calculated in different portions of the calandria tube. By using this model an adequate agreement was achieved between CATHENA calculation and experimental measurement The CATHENA code enables one to investigate the transient and local thermal-mechanical behaviour of the calandria tube

  15. Methodology for full comparative assessment of direct gross glycerin combustion in a flame tube furnace

    Energy Technology Data Exchange (ETDEWEB)

    Maturana, Aymer Yeferson; Pagliuso, Josmar D. [Dept. of Mechanical Engineering. Sao Carlos School of Engineering. University of Sao Paulo, Sao Carlos, SP (Brazil)], e-mails: aymermat@sc.usp.br, josmar@sc.usp.br

    2010-07-01

    This study is to develop a methodology to identify and evaluate the emissions and heat transfer associated to combustion of gross glycerin a by-product of the Brazilian biodiesel manufacture process as alternative energy source. It aims to increase the present knowledge on the matter and to contribute to the improvement of the economic and environmental perspective of biodiesel industry. This methodology was considered to be used for assessment of gross glycerin combustion from three different types of biodiesel (bovine tallow, palm and soy). The procedures for evaluation and quantification of emissions of sulphur and nitrogen oxides, total hydrocarbons, carbon monoxide, carbon dioxide, and acrolein were analyzed, described and standardized. Experimental techniques for mutagenic and toxic effects assessment of gases similarly were analyzed and standardized, as well as the calorific power, the associate heat transfer and fundamentals operational parameters. The methodology was developed, using a full-instrumented flame tube furnace, continuous gas analyzers, a chromatograph, automatic data acquisition systems and other auxiliary equipment. The mutagenic and toxic effects of the study was based on Tradescantia clone KU-20, using chambers of intoxication and biological analytical techniques previously developed and others were specially adapted. The benchmark for the initial set up was based on the performance evaluation of the previous equipment tested with diesel considering its behavior during direct combustion. Finally, the following factors were defined for the combustion of crude glycerin, configurations of equipment types, operational parameters such as air fuel ratio adiabatic temperature and other necessary aspect for successful application of the methodology. The developed and integrated methodology was made available to the concern industry, environmental authorities and researchers as procedures to access the viability of gross glycerin or similar fuels as

  16. Use of response envelopes for seismic margin assessment of reinforced concrete walls and slabs

    Energy Technology Data Exchange (ETDEWEB)

    Ile, Nicolas; Frau, Alberto, E-mail: alberto.frau@cea.fr

    2017-04-01

    Highlights: • Proposal of a method for application of the elliptical envelope to RC shell elements. • Proposal of new algorithms for the seismic margin evaluation for RC shell elements. • Verification of a RC wall 3D structure, using the proposed assessment approach. - Abstract: Seismic safety evaluations of existing nuclear facilities are usually based on the assumption of structural linearity. For the design basis earthquake (DBE), it is reasonable to apply a conventional evaluation of the seismic safety of building structures and carry out a linear elastic analysis to assess the load effects on structural elements. Estimating the seismic capacity of a structural element requires an estimation of the critical combination of responses acting in this structural element and compare this combination with the capacity of the element. By exploiting the response-spectrum-based procedure for predicting the response envelopes in linear structures formulated by Menun and Der Kiureghian (2000a), algorithms are developed for the seismic margin assessment of reinforced concrete shell finite elements. These algorithms facilitate the comparison of the response-spectrum-based envelopes to prescribed capacity surfaces for the purpose of assessing the safety margin of this kind of structures. The practical application of elliptical response envelopes in case of shell finite elements is based on the use of layer models such as those developed by Marti (1990), which transfer the generalized stress field to three layers under the assumption that the two outer layers carry membrane forces and the internal layer carries only the out-of-plane shears. The utility of the assessment approach is discussed with reference to a case study of a 3D structure made of reinforced concrete walls.

  17. Use of response envelopes for seismic margin assessment of reinforced concrete walls and slabs

    International Nuclear Information System (INIS)

    Ile, Nicolas; Frau, Alberto

    2017-01-01

    Highlights: • Proposal of a method for application of the elliptical envelope to RC shell elements. • Proposal of new algorithms for the seismic margin evaluation for RC shell elements. • Verification of a RC wall 3D structure, using the proposed assessment approach. - Abstract: Seismic safety evaluations of existing nuclear facilities are usually based on the assumption of structural linearity. For the design basis earthquake (DBE), it is reasonable to apply a conventional evaluation of the seismic safety of building structures and carry out a linear elastic analysis to assess the load effects on structural elements. Estimating the seismic capacity of a structural element requires an estimation of the critical combination of responses acting in this structural element and compare this combination with the capacity of the element. By exploiting the response-spectrum-based procedure for predicting the response envelopes in linear structures formulated by Menun and Der Kiureghian (2000a), algorithms are developed for the seismic margin assessment of reinforced concrete shell finite elements. These algorithms facilitate the comparison of the response-spectrum-based envelopes to prescribed capacity surfaces for the purpose of assessing the safety margin of this kind of structures. The practical application of elliptical response envelopes in case of shell finite elements is based on the use of layer models such as those developed by Marti (1990), which transfer the generalized stress field to three layers under the assumption that the two outer layers carry membrane forces and the internal layer carries only the out-of-plane shears. The utility of the assessment approach is discussed with reference to a case study of a 3D structure made of reinforced concrete walls.

  18. Flow pattern assessment in tubes with wire coil inserts in laminar and transition regimes

    International Nuclear Information System (INIS)

    Garcia, A.; Solano, J.P.; Vicente, P.G.; Viedma, A.

    2007-01-01

    The paper presents an analysis of the flow mechanisms in tubes with wire coils using hydrogen bubble visualization and PIV techniques. Results have been contrasted with experimental data on pressure drop. The relation between the observed flow patterns and the friction factor has been analysed. The experimental analysis that has been carried out allows one to state that at low Reynolds numbers (Re < 400) the flow in tubes with wire coils is basically similar to the flow in smooth tubes. At Reynolds numbers between 500 and 700 and in short pitch wire coils a recirculating flow appears. The insertion of wires coils in a smooth tube accelerates significantly the transition to turbulence. This is produced at Reynolds numbers between 700 and 1000 depending on the wire pitch

  19. Assessing a nephrology-focused YouTube channel's potential to educate health care providers.

    Science.gov (United States)

    Desai, Tejas; Sanghani, Vivek; Fang, Xiangming; Christiano, Cynthia; Ferris, Maria

    2013-01-01

    YouTube has emerged as a potential teaching tool. Studies of the teaching potential of YouTube videos have not addressed health care provider (HCP) satisfaction; a necessary prerequisite for any teaching tool. We conducted a 4-month investigation to determine HCP satisfaction with a nephrology-specific YouTube channel. The Nephrology On-Demand YouTube channel was analyzed from January 1 through April 30, 2011. Sixty-minute nephrology lectures at East Carolina University were compressed into 10-minute videos and uploaded to the channel. HCPs were asked to answer a 5-point Likert questionnaire regarding the accuracy, currency, objectivity and usefulness of the digital format of the teaching videos. Means, standard deviations and 2-sided chi-square testing were performed to analyze responses. Over 80% of HCPs considered the YouTube channel to be accurate, current and objective. A similar percentage considered the digital format useful despite the compression of videos and lack of audio. The nephrology-specific YouTube channel has the potential to educate HCPs of various training backgrounds. Additional studies are required to determine if such specialty-specific channels can improve knowledge acquisition and retention.

  20. Quantitative assessment of left ventricular systolic wall thickening using multidetector computed tomography

    DEFF Research Database (Denmark)

    Kristensen, Thomas S; Kofoed, Klaus F; Møller, Daniel V

    2009-01-01

    BACKGROUND: Multidetector computed tomography (MDCT) of the heart provides both anatomical and functional information. The objective of this study was to evaluate the accuracy of quantitative assessment of left ventricular contractile function in relation to two-dimensional transthoracic echocard......BACKGROUND: Multidetector computed tomography (MDCT) of the heart provides both anatomical and functional information. The objective of this study was to evaluate the accuracy of quantitative assessment of left ventricular contractile function in relation to two-dimensional transthoracic...... echocardiography (TTE). MATERIALS AND METHODS: Sixty-four patients with known or suspected coronary artery disease underwent ECG-gated 64-slice MDCT and TTE. Regional left ventricular contractile function was measured by percent systolic wall thickening (SWT) in 16 myocardial segments using MDCT, and compared...

  1. Progress in the engineering design and assessment of the European DEMO first wall and divertor plasma facing components

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, Thomas R., E-mail: tom.barrett@ukaea.uk [CCFE, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Ellwood, G.; Pérez, G.; Kovari, M.; Fursdon, M.; Domptail, F.; Kirk, S.; McIntosh, S.C.; Roberts, S.; Zheng, S. [CCFE, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Boccaccini, L.V. [KIT, INR, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); You, J.-H. [Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching (Germany); Bachmann, C. [EUROfusion, PPPT, Boltzmann Str. 2, 85748 Garching (Germany); Reiser, J.; Rieth, M. [KIT, IAM, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Visca, E.; Mazzone, G. [ENEA, Unità Tecnica Fusione, ENEA C. R. Frascati, via E. Fermi 45, 00044 Frascati (Italy); Arbeiter, F. [KIT, INR, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Domalapally, P.K. [Research Center Rez, Hlavní 130, 250 68 Husinec – Řež (Czech Republic)

    2016-11-01

    Highlights: • The engineering of the plasma facing components for DEMO is an extreme challenge. • PFC overall requirements, methods for assessment and designs status are described. • Viable divertor concepts for 10 MW/m{sup 2} surface heat flux appear to be within reach. • The first wall PFC concept will need to vary poloidally around the wall. • First wall coolant, structural material and PFC topology are open design choices. - Abstract: The European DEMO power reactor is currently under conceptual design within the EUROfusion Consortium. One of the most critical activities is the engineering of the plasma-facing components (PFCs) covering the plasma chamber wall, which must operate reliably in an extreme environment of neutron irradiation and surface heat and particle flux, while also allowing sufficient neutron transmission to the tritium breeding blankets. A systems approach using advanced numerical analysis is vital to realising viable solutions for these first wall and divertor PFCs. Here, we present the system requirements and describe bespoke thermo-mechanical and thermo-hydraulic assessment procedures which have been used as tools for design. The current first wall and divertor designs are overviewed along with supporting analyses. The PFC solutions employed will necessarily vary around the wall, depending on local conditions, and must be designed in an integrated manner by analysis and physical testing.

  2. An assessment of heat transfer models of water flow in helically coiled tubes based on selected experimental datasets

    International Nuclear Information System (INIS)

    Gou, Junli; Ma, Haifu; Yang, Zijiang; Shan, Jianqiang

    2017-01-01

    Highlights: •A review of heat transfer characteristics for water flow in helically coiled tubes are conducted. •An assessment of heat transfer models under different heat transfer modes in helically coiled tubes are performed. •This work could provide references for the use of the correlations and for further studies. -- Abstract: This paper presents an assessment of the heat transfer models under different heat transfer modes for water flow in helically coiled tubes based on the compiled datasets from the reviewed literatures. For single phase flow, most of the correlations of the heat transfer coefficient can fit well to the experiments. The correlations of Xin-Ebadian, Dravid and Kalb-Seader for laminar flow and those of Seban-McLaughlim, Mori-Nakayama, Xin-Ebadian, Hardik, Rogers-Mayhew, Mikaila-Poskas and El-Genk-Schriener for turbulent flow are recommended. For flow boiling heat transfer, Steiner-Taborek correlation could be utilized to predict the boiling heat transfer coefficients in helically coiled tubes for a relatively wide range of parameters. For dryout quality, the correlations of Hwang et al. and Santini et al. give relatively better predictions than others. However, more accurate correlations for flow boiling heat transfer coefficient and dryout quality need to be developed based on further investigations with wider parameter ranges in the future. The present work could provide references for the investigators for future uses of those correlations and for performing further investigations on the heat transfer characteristics of water flow in helically coiled tubes.

  3. 'How to stop a nosebleed': an assessment of the quality of epistaxis treatment advice on YouTube.

    Science.gov (United States)

    Haymes, A T; Harries, V

    2016-08-01

    Video hosting websites are increasingly being used to disseminate health education messages. This study aimed to assess the quality of advice contained within YouTube videos on the conservative management of epistaxis. YouTube.com was searched using the phrase 'how to stop a nosebleed'. The first 50 videos were screened. Objective advice scores and subjective production quality scores were attributed by independent raters. Forty-five videos were analysed. The mean advice score was 2.0 out of 8 and the mean production quality score was 1.6 out of 3. There were no correlations between a video's advice score and its search results rank (ρ = -0.28, p = 0.068), its view count (ρ = 0.20, p = 0.19) or its number of 'likes' (ρ = 0.21, p = 0.18). The quality of information on conservative epistaxis management within YouTube videos is extremely variable. A high search rank is no indication of video quality. Many videos proffer inappropriate and dangerous 'alternative' advice. We do not recommend YouTube as a source for patient information.

  4. A clinically relevant in vivo model for the assessment of scaffold efficacy in abdominal wall reconstruction

    Directory of Open Access Journals (Sweden)

    Jeffrey CY Chan

    2016-12-01

    Full Text Available An animal model that allows for assessment of the degree of stretching or contraction of the implant area and the in vivo degradation properties of biological meshes is required to evaluate their performance in vivo. Adult New Zealand rabbits underwent full thickness subtotal unilateral rectus abdominis muscle excision and were reconstructed with the non-biodegradable Peri-Guard®, Prolene® or biodegradable Surgisis® meshes. Following 8 weeks of recovery, the anterior abdominal wall tissue samples were collected for measurement of the implant dimensions. The Peri-Guard and Prolene meshes showed a slight and obvious shrinkage, respectively, whereas the Surgisis mesh showed stretching, resulting in hernia formation. Surgisis meshes showed in vivo biodegradation and increased collagen formation. This surgical rabbit model for abdominal wall defects is advantageous for evaluating the in vivo behaviour of surgical meshes. Implant area stretching and shrinkage were detected corresponding to mesh properties, and histological analysis and stereological methods supported these findings.

  5. The use of cone beam computed tomography in the postoperative assessment of orbital wall fracture reconstruction.

    Science.gov (United States)

    Tsao, Kim; Cheng, Andrew; Goss, Alastair; Donovan, David

    2014-07-01

    Computed tomography (CT) is currently the standard in postoperative evaluation of orbital wall fracture reconstruction, but cone beam computed tomography (CBCT) offers potential advantages including reduced radiation dose and cost. The purpose of this study is to examine objectively the image quality of CBCT in the postoperative evaluation of orbital fracture reconstruction, its radiation dose, and cost compared with CT. Four consecutive patients with orbital wall fractures in whom surgery was indicated underwent orbital reconstruction with radio-opaque grafts (bone, titanium-reinforced polyethylene, and titanium plate) and were assessed postoperatively with orbital CBCT. CBCT was evaluated for its ability to provide objective information regarding the adequacy of orbital reconstruction, radiation dose, and cost. In all patients, CBCT was feasible and provided hard tissue image quality comparable to CT with significantly reduced radiation dose and cost. However, it has poorer soft tissue resolution, which limits its ability to identify the extraocular muscles, their relationship to the reconstructive graft, and potential muscle entrapment. CBCT is a viable alternative to CT in the routine postoperative evaluation of orbital fracture reconstruction. However, in the patient who develops gaze restriction postoperatively, conventional CT is preferred over CBCT for its superior soft tissue resolution to exclude extraocular muscle entrapment.

  6. Tube-in-shell heat exchangers

    International Nuclear Information System (INIS)

    Richardson, J.

    1976-01-01

    Tube-in-shell heat exchangers normally comprise a bundle of parallel tubes within a shell container, with a fluid arranged to flow through the tubes in heat exchange with a second fluid flowing through the shell. The tubes are usually end supported by the tube plates that separate the two fluids, and in use the tube attachments to the tube plates and the tube plates can be subject to severe stress by thermal shock and frequent inspection and servicing are required. Where the heat exchangers are immersed in a coolant such as liquid Na such inspection is difficult. In the arrangement described a longitudinally extending central tube is provided incorporating axially spaced cylindrical tube plates to which the opposite ends of the tubes are attached. Within this tube there is a tubular baffle that slidably seals against the wall of the tube between the cylindrical tube plates to define two co-axial flow ducts. These ducts are interconnected at the closed end of the tube by the heat exchange tubes and the baffle comprises inner and outer spaced walls with the interspace containing Ar. The baffle is easily removable and can be withdrawn to enable insertion of equipment for inspecting the wall of the tube and tube attachments and to facilitate plugging of defective tubes. Cylindrical tube plates are believed to be superior for carrying pressure loads and resisting the effects of thermal shock. Some protection against thermal shock can be effected by arranging that the secondary heat exchange fluid is on the tube side, and by providing a thermal baffle to prevent direct impingement of hot primary fluid on to the cylindrical tube plates. The inner wall of the tubular baffle may have flexible expansible region. Some nuclear reactor constructions incorporating such an arrangement are described, including liquid metal reactors. (U.K.)

  7. A new approach combining analytical methods for workplace exposure assessment of inhalable multi-walled carbon nanotubes

    NARCIS (Netherlands)

    Tromp, P.C.; Kuijpers, E.; Bekker, C.; Godderis, L.; Lan, Q.; Jedynska, A.D.; Vermeulen, R.; Pronk, A.

    2017-01-01

    To date there is no consensus about the most appropriate analytical method for measuring carbon nanotubes (CNTs), hampering the assessment and limiting the comparison of data. The goal of this study is to develop an approach for the assessment of the level and nature of inhalable multi-wall CNTs

  8. Heat Exchanger Tube Inspection of Nuclear Power Plants using IRIS Technique

    International Nuclear Information System (INIS)

    Yoon, Byung Sik; Yang, Seung Han; Song, Seok Yoon; Kim, Yong Sik; Lee, Hee Jong

    2005-01-01

    Inspection of heat exchange tubing include steam generator of nuclear power plant mostly performed with eddy current method. Recently, various inspection technique is available such as remote field eddy current, flux leakage and ultrasonic methods. Each of these techniques has its merits and limitations. Electromagnetic techniques are very useful to locate areas of concern but sizing is hard because of the difficult interpretation of an electric signature. On the other hand, ultrasonic methods are very accurate in measuring wall loss damage, and are reliable for detecting cracks. Additionally ultrasound methods is not affected by support plates or tube sheets and variation of electrical conductivity or permeability. Ultrasound data is also easier to analyze since the data displayed is generally the remaining wall thickness. It should be emphasized that ultrasound is an important tool for sizing defects in tubing. In addition, it can be used in situations where eddy current or remote field eddy current is not reliable, or as a flaw assessment tool to supplement the electromagnetic data. The need to develop specialized ultrasonic tools for tubing inspection was necessary considering the limitations of electromagnetic techniques to some common inspection problems. These problems the sizing of wall loss in carbon steel tubes near the tube sheet or support plate, sizing internal erosion damage, and crack detection. This paper will present an IRIS(Internal Rotating Inspection System) ultrasonic tube inspection technique for heat exchanger tubing in nuclear power plant and verify inspection reliability for artificial flaw embedded to condenser tube

  9. Assessment of hypervapotron heat sink performance using CFD under DEMO relevant first wall conditions

    Energy Technology Data Exchange (ETDEWEB)

    Domalapally, Phani, E-mail: p_kumar.domalapally@cvrez.cz

    2016-11-01

    Highlights: • Performance of Hypervapotron heat sink was tested for First wall limiter application. • Two different materials were tested Eurofer 97 and CuCrZr at PWR conditions. • Simulations were performed to see the effect of the different inlet conditions and materials on the maximum temperature. • It was found that CuCrZr heat sink performance is far better than Eurofer heat sink at the same operating conditions. - Abstract: Among the proposed First Wall (FW) cooling concepts for European Demonstration Fusion Power Plant (DEMO), water cooled FW is one of the options. The heat flux load distribution on the FW of the DEMO reactor is not yet precisely defined. But if the heat loads on the FW are extrapolated from ITER conditions, the numbers are quite high and have to be handled none the less. The design of the FW itself is challenging as the thermal conductivity ratio of heat sink materials in ITER (CuCrZr) and in DEMO (Eurofer 97) is ∼10–12 and the operating conditions are of Pressurized Water Reactor (PWR) in DEMO instead of 70 °C and 4 MPa as in ITER. This paper analyzes the performance of Hypervapotron (HV) heat sink for FW limiter application under DEMO conditions. Where different materials, temperatures, heat fluxes and velocities are considered to predict the performance of the HV, to establish its limits in handling the heat loads before reaching the upper limits from temperature point of view. In order to assess the performance, numerical simulations are performed using commercial CFD code, which was previously validated in predicting the thermal hydraulic performance of HV geometry. Based on the results the potential usage of HV heat sink for DEMO will be assessed.

  10. Advantages and disadvantages of hysterosonosalpingography in the assessment of the reproductive status of uterine cavity and fallopian tubes

    International Nuclear Information System (INIS)

    Radic, Vanja; Canic, Tomislav; Valetic, Josip; Duic, Zeljko

    2005-01-01

    Background: Hysterosonosalpingography as a contrast ultrasound method is safer, cheaper and easier to perform than hysterosalpingography in the assessment of the uterine cavity and fallopian tubes. Is it feasible for all patients? Which is the main problem in the evaluation of target structures by ultrasound? Methods: In a prospective study, 68 patients in the initial stage of the infertility treatment were examined by hysterosonosalpingography using saline NaCl infundibile[reg] and Echovist[reg] as contrast media. Subsequently, further status of the tubes and uterine cavity was assessed by the 'gold standards', laparoscopy and hysteroscopy. Results: Sensitivity and specificity of hysterosonosalpingography using NaCl infundibile[reg] for evaluation of the uterine cavity was 100 and 88.8%, respectively. Negative predictive value was 100% and positive predictive value 97%. Sensitivity and specificity of the method for the assessment of the tubal status was 100 and 66%, respectively, negative predictive value was 100% and positive predictive value was 61%. For the assessment of tubal patency using positive contrast Echovist[reg] the method has shown 100% sensibility and negative predictive value again but it reached a specificity of 77% and a positive predictive value of 70%. There were no evident complications during or after the procedure. Conclusion: Hysterosonosalpingography is useful in making decisions regarding further procedures for the diagnosis and treatment of infertility. Uterine cavity evaluation using saline is the method of choice. Tubal patency can be assessed only under ideal sonographic conditions. The method is feasible for early assessment of the reproductive status of uterine cavity and fallopian tubes as a simple, safe and cheap outpatient method prior to any following invasive procedure or even histerosalpingography

  11. Advantages and disadvantages of hysterosonosalpingography in the assessment of the reproductive status of uterine cavity and fallopian tubes

    Energy Technology Data Exchange (ETDEWEB)

    Radic, Vanja; Canic, Tomislav; Valetic, Josip; Duic, Zeljko

    2005-02-01

    Background: Hysterosonosalpingography as a contrast ultrasound method is safer, cheaper and easier to perform than hysterosalpingography in the assessment of the uterine cavity and fallopian tubes. Is it feasible for all patients? Which is the main problem in the evaluation of target structures by ultrasound? Methods: In a prospective study, 68 patients in the initial stage of the infertility treatment were examined by hysterosonosalpingography using saline NaCl infundibile[reg] and Echovist[reg] as contrast media. Subsequently, further status of the tubes and uterine cavity was assessed by the 'gold standards', laparoscopy and hysteroscopy. Results: Sensitivity and specificity of hysterosonosalpingography using NaCl infundibile[reg] for evaluation of the uterine cavity was 100 and 88.8%, respectively. Negative predictive value was 100% and positive predictive value 97%. Sensitivity and specificity of the method for the assessment of the tubal status was 100 and 66%, respectively, negative predictive value was 100% and positive predictive value was 61%. For the assessment of tubal patency using positive contrast Echovist[reg] the method has shown 100% sensibility and negative predictive value again but it reached a specificity of 77% and a positive predictive value of 70%. There were no evident complications during or after the procedure. Conclusion: Hysterosonosalpingography is useful in making decisions regarding further procedures for the diagnosis and treatment of infertility. Uterine cavity evaluation using saline is the method of choice. Tubal patency can be assessed only under ideal sonographic conditions. The method is feasible for early assessment of the reproductive status of uterine cavity and fallopian tubes as a simple, safe and cheap outpatient method prior to any following invasive procedure or even histerosalpingography.

  12. Utilization of YouTube as a Tool to Assess Patient Perception Regarding Implanted Cardiac Devices.

    Science.gov (United States)

    Hayes, Kevin; Mainali, Prajeena; Deshmukh, Abhishek; Pant, Sadip; Badheka, Apurva O; Paydak, Hakan

    2014-07-01

    The outreach of YouTube may have a dramatic role in the widespread dissemination of knowledge on implantable cardioverter devices (ICD). This study was designed to review and analyze the information available on YouTube pertaining to implantable cardiac devices such as implantable cardioverter defibrillators (ICDs) and pacemakers. YouTube was queried for the terms "ICD", "Implantable Cardioverter Defibrillator", and "Pacemaker". The videos were reviewed and categorized as according to content; number of views and "likes" or "dislikes" was recorded by two separate observers. Of the 55 videos reviewed, 18 of the videos were categorized as patient education, 12 were advertisements, 8 were intraoperative videos documenting the device implantation procedures, 7 of the videos were produced to document personal patient experiences, and 4 were categorized as documentation of a public event. 3 were intended to educate health care workers. The remaining 3 were intended to raise public awareness about sudden cardiac death. The videos portraying intraoperative procedures generated the most "likes" or "dislikes" per view. While YouTube provides a logical platform for delivery of health information, the information on this platform is not regulated. Initiative by reputed authorities and posting accurate information in such platform can be a great aid in public education regarding device therapy.

  13. Residual indicator bacteria in autosampler tubing: a field and laboratory assessment.

    Science.gov (United States)

    Hathaway, J M; Hunt, W F; Guest, R M; McCarthy, D T

    2014-01-01

    Microbial contamination in surface waters has become a worldwide cause for concern. As efforts are made to reduce this contamination, monitoring is integral to documenting and evaluating water quality improvements. Autosamplers are beneficial in such monitoring efforts, as large data sets can be generated with minimized effort. The extent to which autosamplers can be utilized for microbial monitoring is largely unknown due to concerns over contamination. Strict sterilization regimes for components contacting the water being sampled are difficult, and sometimes logistically implausible, when utilizing autosamplers. Field experimentation showed contamination of fecal coliform in autosamplers to be more of a concern than that of Escherichia coli. Further study in a controlled laboratory environment suggested that tubing configuration has a significant effect on residual E. coli concentrations in sampler tubing. The amount of time that passed since the last sample was collected from a given sampler (antecedent dry weather period - DWP) tubing was also a significant factor. At a DWP of 7 days, little to no contamination was found. Thus, simple protocols such as providing positive drainage of tubing between sample events and programming samplers to include rinses will reduce concerns of contamination in autosamplers.

  14. Fiber Fabry-Perot Force Sensor with Small Volume and High Performance for Assessing Fretting Damage of Steam Generator Tubes.

    Science.gov (United States)

    Huang, Peijian; Wang, Ning; Li, Junying; Zhu, Yong; Zhang, Jie

    2017-12-13

    Measuring the radial collision force between the steam generator tube (SGT) and the tube support plate (TSP) is essential to assess the fretting damage of the SGT. In order to measure the radial collision force, a novel miniaturized force sensor based on fiber Fabry-Perot (F-P) was designed, and the principle and characteristics of the sensor were analyzed in detail. Then, the F-P force sensor was successfully fabricated and calibrated, and the overall dimensions of the encapsulated fiber F-P sensor were 17 mm × 5 mm × 3 mm (L × W × H). The sensor works well in humid, high pressure (10 MPa), high temperature (350 °C), and vibration (40 kHz) environments. Finally, the F-P force sensors were installed in a 1:1 steam generator test loop, and the radial collision force signals between the SGT and the TSP were obtained. The experiments indicated that the F-P sensor with small volume and high performance could help in assessing the fretting damage of the steam generator tubes.

  15. Clinical assessment compared with chest X-Ray after removal of chest tube to diagnose pneumothorax

    International Nuclear Information System (INIS)

    Majeed, F. A.; Noor, Q. U. H.; Mehmood, U.; Imtiaz, T.; Zafar, U.

    2017-01-01

    Objective: To evaluate clinical judgment in ruling out pneumothorax during the removal of the chest tube by auscultating the chest before removal and after the extubation of the chest tube in comparison to x ray radiological results. Study Design: Descriptive cross sectional study. Place and Duration of Study: Combined Military Hospital (CMH) Lahore Pakistan, from August 2015 to March 2016. Material and Methods: A sample size of 100 was calculated. Patients were selected via non probability purposive sampling. Children under 14 years were not included. The patients with mal-positioned chest tube, surgical site infection, air leak and the patients with more than one chest tube on one side were excluded. A proforma was made and filled by one person. Chest tubes were removed by two trained senior registrars according to a protocol devised. It was ensured that there was no air leak present before removal clinically and radiologically. Another chest x-ray was done within 24 hours of extubation to detect any pathology that might have occurred during the process. Any complication in the patient clinically was observed till the x-ray film became available. Two sets of readings were obtained. Set A included auscultation findings and set B included x ray results. Results: Out of 100 patients, 60 (60 percent) were males and 40 (40 percent) females. The ages of the patients ranged between 17-77 years. Mean age of the patient was 43.27 ± 17.05 years. In set A out of 100 (100 percent) no pneumothorax developed clinically. In set B out of 100 patients 99 (99 percent) showed no pneumothorax on chest x ray, only 1 (1 percent) showed pneumothorax which was not significant (less than 15 percent on X ray). However, the patient remained asymptomatic clinically and there was no need of reinsertion of the chest tube. Conclusion: Auscultatory findings in diagnosing a significant pneumothorax are justified. Hence, if the chest tube is removed according to the protocol, clinically by

  16. Contribution to the study of turbulent flow in cylindrical tubing with porous walls; Contribution a l'etude de l'ecoulement turbulent dans une conduite cylindrique a paroi poreuse

    Energy Technology Data Exchange (ETDEWEB)

    Burnage, H

    1962-07-01

    A theoretical study has been made of a fully developed turbulent flow in cylindrical tubing of circular cross-section subjected to a uniform suction through the walls. This study has made it possible to find a relationship giving the friction coefficient at the wall in terms of the amount of local suction and of the longitudinal static pressure gradient. A method for calculating the Reynolds tensions from the pressure measurements has been devised. An experimental system has been developed. Pressure measurements have been made. By using experimental results it has been possible to obtain a semi empirical expression for the friction coefficient at the wall, in terms of the amount of suction of the inlet Reynolds number, and of the abscissa. (author) [French] Une etude theorique de refoulement turbulent pleinement developpe dans une conduite cylindrique de section circulaire soumise a une aspiration parietale uniforme a ete entreprise. Elle a permis de trouver une relation donnant le coefficient de frottement a la paroi en fonction du taux d'aspiration local et du gradient de pression statique longitudinal. Une methode de calcul des tensions de Reynolds a partir des mesures de pression a ete etablie. Un dispositif experimental a ete realise et mis au point. Des mesures de pression ont ete effectuees. L'utilisation des resultats experimentaux a permis d'obtenir une expression semi-empirique du coefficient de frottement a la paroi en fonction du taux d'aspiration, du nombre de Reynolds d'entree et de l'abscisse. (auteur)

  17. Assessment of First Wall and Blanket Options with the Use of Liquid Breeder

    International Nuclear Information System (INIS)

    Wong, C.P.C.; Malang, S.; Sawan, M.

    2005-01-01

    As candidate blanket concepts for a U.S. advanced reactor power plant design, with consideration of the time frame for ITER development, we assessed first wall and blanket design concepts based on the use of reduced activation ferritic steel as structural material and liquid breeder as the coolant and tritium breeder. The liquid breeder choice includes the conventional molten salt Li 2 BeF 4 and the low melting point molten salts such as LiBeF 3 and LiNaBeF 4 (FLiNaBe). Both self-cooled and dual coolant molten salt options were evaluated. We have also included the dual coolant leadeutectic Pb-17Li design in our assessment. We take advantage of the molten salt low electrical and thermal conductivity to minimize impacts from the MHD effect and the heat losses from the breeder to the actively cooled steel structure. For the Pb-17Li breeder we employ flow channel inserts of SiC f /SiC composite with low electrical and thermal conductivity to perform respective insulation functions. We performed preliminary assessments of these design options in the areas of neutronics, thermal-hydraulics, safety, and power conversion system. Status of the R and D items of selected high performance blanket concepts is reported. Results from this study will form the technical basis for the formulation of the U.S. ITER test module program and corresponding test plan

  18. Steam Generator Tube Integrity Program: Surry Steam Generator Project, Hanford site, Richland, Benton County, Washington: Environmental assessment

    International Nuclear Information System (INIS)

    1980-03-01

    The US Nuclear Regulatory Commission (NRC) has placed a Nuclear Regulatory Research Order with the Richland Operations Office of the US Department of Energy (DOE) for expanded investigations at the DOE Pacific Northwest Laboratory (PNL) related to defective pressurized water reactor (PWR) steam generator tubing. This program, the Steam Generator Tube Integrity (SGTI) program, is sponsored by the Metallurgy and Materials Research Branch of the NRC Division of Reactor Safety Research. This research and testing program includes an additional task requiring extensive investigation of a degraded, out-of-service steam generator from a commercial nuclear power plant. This comprehensive testing program on an out-of-service generator will provide NRC with timely and valuable information related to pressurized water reactor primary system integrity and degradation with time. This report presents the environmental assessment of the removal, transport, and testing of the steam generator along with decontamination/decommissioning plans

  19. Assessment of ventricular wall motion with focused echocardiography during cardiac arrest to predict survival

    Directory of Open Access Journals (Sweden)

    Can Ozen

    2016-03-01

    Full Text Available Objectives: Our primary goal is to investigate the hypothesis that in patients with a detectable ventricular wall motion (VWM in cardiac ultrasonography (US during cardiopulmonary resuscitation (CPR, survival rate is significantly more than in patients without VWM in US. Material and methods: In our prospective, single center study, 129 adult cardiac arrest (CA patients were enrolled. Cardiac US according to Focus Assessed Transthoracic Echo (FATE protocol was performed before CPR. Presence of VWM was recorded on forms along with demographic data, initial rhythm, CA location, presence of return of spontaneous circulation (ROSC and time until ROSC was obtained. Results: 129 patients were included. ROSC was obtained in 56/77 (72.7% patients with VWM and 3/52 (5.8% patients without VWM which is statistically significant (p > 0.001. Presence of VWM is 95% (95% CI: 0.95–0.99 sensitive and 70% (95% CI: 0.58–0.80 specific for ROSC. 43/77 (55.8% patients with VWM and 1 (1.9% of 52 patients without VWM survived to hospital admission which was statistically significant (p < 0.001. Presence of VWM was 100% (95% CI: 0.87–1.00 sensitive and 54% (95% CI: 0.43–0.64 specific for survival to hospital admission. Conclusion: No patient without VWM in US survived to hospital discharge. Only 3 had ROSC in emergency department and only 1 survived to hospital admission. This data suggests no patient without VWM before the onset of CPR survived to hospital discharge and this may be an indication to end resuscitative efforts early in these patients. Keywords: Cardiopulmonary resuscitation, Ultrasonography, Echocardiography, Ventricular wall motion

  20. NON-INVASIVE METHODS OF THE WORK-UP FOR ASSESSMENT OF MORPHOLOGIC AND FUNCTIONAL STATE OF THE SIGMOID WALL

    Directory of Open Access Journals (Sweden)

    A. E. Mashkov

    2015-01-01

    Full Text Available Background: Prolonged colonic congestion in children with chronic constipation and dolichosigma are characterized  by a permanent imbalance of gut microflora, secondary inflammation and degeneration of the sigmoid wall. There is plenty of research papers on the optic non-invasive diagnostics in medicine, based on spectrophotometry and laser spectral analysis. Aim: To study morphologic and functional state  of the sigmoid wall for detection of inflammation  and  degeneration in the  sigmoid  wall and  optimization  of treatment of children with dolichosigma  and long-standing constipation. Materials and methods: From 2009 to 2014, 30 children with dolichosigma  were seen in the Department of Pediatric surgery of MONIKI. All patients  were  hospitalized  after unsuccessful conservative  treatment in in-patient  clinics of the Moscow Region. The children underwent a set of investigations  for objective assessment of degree of the secondary  inflammatory and degenerative abnormalities  in the sigmoid wall, such as microbiological assessment, cytological assessment and fluorescent  diagnostics.  Results:  There  was  no   caused  by dolichosigma. It maintains  chronic inflammation  and  may play an indirect  role in abnormalities  of gut  motor  function. Inflammatory and  degenerative abnormalities  were  confirmed by a cytological investigation  of wall-adjacent biopsy of the  sigma. The results of the  complex assessment showed  moderate inflammation  and degeneration in the  sigmoid wall in 20 children; subsequent conservative treatment of chronic colostasis was effective. Ten children had advanced secondary inflammatory and degenerative abnormalities of the  sigmoid  wall, with high  levels of elastin and collagen in the colon wall. Surgery was performed in 6 children with the highest degree of fibrous transformation of the sigma. Conclusion: Complex assessment of the sigmoid wall, including

  1. Optical Fiber Demodulation System with High Performance for Assessing Fretting Damage of Steam Generator Tubes.

    Science.gov (United States)

    Huang, Peijian; Wang, Ning; Li, Junying; Zhu, Yong; Zhang, Jie; Xi, Zhide

    2018-01-12

    In order to access the fretting damage of the steam generator tube (SGT), a fast fiber Fabry-Perot (F-P) non-scanning correlation demodulation system based on a super luminescent light emitting diode (SLED) was performed. By demodulating the light signal coming out from the F-P force sensor, the radial collision force between the SGT and the tube support plate (TSP) was interrogated. For higher demodulation accuracy, the effects of the center wavelength, bandwidth, and spectrum noise of SLED were discussed in detail. Specially, a piezoelectric ceramic transducer (PZT) modulation method was developed to get rid of the interference of mode coupling induced by different types of fiber optics in the demodulation system. The reflectivity of optical wedge and F-P sensor was optimized. Finally, the demodulation system worked well in a 1:1 steam generator test loop and successfully demodulated a force signal of 32 N with a collision time of 2 ms.

  2. Reliability assessment of serviceability performance of braced retaining walls using a neural network approach

    Science.gov (United States)

    Goh, A. T. C.; Kulhawy, F. H.

    2005-05-01

    In urban environments, one major concern with deep excavations in soft clay is the potentially large ground deformations in and around the excavation. Excessive movements can damage adjacent buildings and utilities. There are many uncertainties associated with the calculation of the ultimate or serviceability performance of a braced excavation system. These include the variabilities of the loadings, geotechnical soil properties, and engineering and geometrical properties of the wall. A risk-based approach to serviceability performance failure is necessary to incorporate systematically the uncertainties associated with the various design parameters. This paper demonstrates the use of an integrated neural network-reliability method to assess the risk of serviceability failure through the calculation of the reliability index. By first performing a series of parametric studies using the finite element method and then approximating the non-linear limit state surface (the boundary separating the safe and failure domains) through a neural network model, the reliability index can be determined with the aid of a spreadsheet. Two illustrative examples are presented to show how the serviceability performance for braced excavation problems can be assessed using the reliability index.

  3. Array-Based Ultrawideband through-Wall Radar: Prediction and Assessment of Real Radar Abilities

    Directory of Open Access Journals (Sweden)

    Nadia Maaref

    2013-01-01

    Full Text Available This paper deals with a new through-the-wall (TTW radar demonstrator for the detection and the localisation of people in a room (in a noncooperative way with the radar situated outside but in the vicinity of the first wall. After modelling the propagation through various walls and quantifying the backscattering by the human body, an analysis of the technical considerations which aims at defining the radar design is presented. Finally, an ultrawideband (UWB frequency modulated continuous wave (FMCW radar is proposed, designed, and implemented. Some representative trials show that this radar is able to localise and track moving people behind a wall in real time.

  4. Assessment of RELAP5/MOD3.3 condensation models for the tube bundle condensation in the PCCS of ESBWR

    International Nuclear Information System (INIS)

    Zhou, W.; Wolf, B.; Revankar, S.T.

    2011-01-01

    The passive containment condenser system (PCCS) in an ESBWR reactor consists of vertical tube bundle submerged in a large pool of water. The condensation model for the PCCS in a thermalhydraulics code RELAP5/MOD3.3 consists of the default Nusselt model and an alternate condensation model from UCB condensation correlation. An assessment of the PCCS condensation model in RELAP5/MOD3.3 was carried out using experiments conducted on a single tube and tube bundle PCCS tests at Purdue University. The experimental conditions were simulated with the default and the alternate condensation models in the REALP5/MOD3.3 beta version of the code. The default model and the UCB model (alternate model) give quite different results on condensation heat transfer for the PCCS. The default model predicts complete condensation well whereas the UCB model predicts the through flow condensation well. Based on this study it was found that none of the models in REALP5 can predict complete condensation as well as the through flow condensation well. (author)

  5. Assessment of RELAP5/MOD3.3 condensation models for the tube bundle condensation in the PCCS of ESBWR

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, W., E-mail: wenzzhou@cityu.edu.hk [Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong (China); Wolf, B. [Purdue University, West Lafayette, IN 47907 (United States); Revankar, S. [Purdue University, West Lafayette, IN 47907 (United States); POSTECH, Pohang (Korea, Republic of)

    2013-11-15

    The passive containment condenser system (PCCS) in an ESBWR reactor consists of vertical tube bundle submerged in a large pool of water. The condensation model for the PCCS in a thermalhydraulics code RELAP5/MOD3.3 consists of the default Nusselt model and an alternate condensation model from UCB condensation correlation. An assessment of the PCCS condensation model in RELAP5/MOD3.3 was carried out using experiments conducted on a single tube and tube bundle PCCS tests at Purdue University. The experimental conditions were simulated with the default and the alternate condensation models in the REALP5/MOD3.3 beta version of the code. The default model and the UCB model (alternate model) give quite different results on condensation heat transfer for the PCCS. The default model predicts complete condensation well whereas the UCB model predicts the through flow condensation well. Based on this study it was found that none of the models in REALP5 can predict complete condensation as well as the through flow condensation well.

  6. Flowmeter with silicon flow tube

    NARCIS (Netherlands)

    Lammerink, Theodorus S.J.; Dijkstra, Marcel; Haneveld, J.; Lötters, Joost Conrad

    2009-01-01

    A flowmeter comprising a system chip with a silicon substrate provided on a carrier, in an opening whereof at least one silicon flow tube is provided for transporting a medium whose flow rate is to be measured, said tube having two ends that issue via a wall of the opening into channels coated with

  7. Flow laminarization and heat transfer crisis in tubes while intense heating of turbulent flow of a gas endothermically dissociating on a wall

    International Nuclear Information System (INIS)

    Kurganov, V.A.; Gladuntsov, A.I.

    1977-01-01

    Analysed are the experimental data obtained for heat transfer to gaseous dissociating ammonium (NH 3 ) under heating in round pipes (steel Kh18N10T) at developed eddying input flow and marginal condition of heat supply gsub(c) approximately equal to const in the ranges of the following parameters: p=3-10 atm; Tsub(input)=310-720 K; Tsub(c) ( 3 ; gsub(c)/-anti rho W 8.8 kJ/kg; gsub(c)/(anti rho WCsub(p) sub(input)Tsub(input)) (<=) 0.0104; 1/d (<=) 150 (where Tsub(c) is the wall temperature, gsub(c) the heat flow density on wall, and anti rho W velocity). The discussion involves phenomena of worsened heat transfer at high heat loads. The authors show the basic relationship between these phenomena and laminarization of the near-wall flow at the input site of the pipe. The regularities of heat transfer were noted to undergo substantial transformation under laminarized flow

  8. Enhanced Hot Tensile Ductility of Mg-3Al-1Zn Alloy Thin-Walled Tubes Processed Via a Combined Severe Plastic Deformation

    Science.gov (United States)

    Fata, A.; Eftekhari, M.; Faraji, G.; Mosavi Mashhadi, M.

    2018-05-01

    In the current study, combined parallel tubular channel angular pressing (PTCAP) and tube backward extrusion (TBE), as a recently developed severe plastic deformation (SPD) method, were applied at 300 °C on a commercial Mg-3Al-1Zn alloy tubes to achieve an ultrafine grained structure. Then, the microstructure, hardness, tensile properties, and fractography evaluations were done at room temperature on the SPD-processed samples. Also, to study the hot tensile ductility of the SPD-processed samples, tensile testing was performed at an elevated temperature of 400 °C, and then, the fractured surface of the tensile samples was studied. It was observed that a bimodal microstructure, with large gains surrounded by many tiny ones, was created in the sample processed by PTCAP followed by TBE. This microstructure led to reach higher hardness and higher strength at room temperature and also led to reach very high elongation to failure ( 181%) at 400 °C. Also, the value of elongation to failure for this sample was 14.1% at room temperature. The fractographic SEM images showed the occurrence of predominately ductile fracture in the samples pulled at 400 °C. This was mostly due to the nucleation of microvoids and their subsequent growth and coalescence with each other.

  9. Pressure tube reactor

    International Nuclear Information System (INIS)

    Seki, Osamu; Kumasaka, Katsuyuki.

    1988-01-01

    Purpose: To remove the heat of reactor core using a great amount of moderators at the periphery of the reactor core as coolants. Constitution: Heat of a reactor core is removed by disposing a spontaneous recycling cooling device for cooling moderators in a moderator tank, without using additional power driven equipments. That is, a spontaneous recycling cooling device for cooling the moderators in the moderator tank is disposed. Further, the gap between the inner wall of a pressure tube guide pipe disposed through the vertical direction of a moderator tank and the outer wall of a pressure tube inserted through the guide pipe is made smaller than the rupture distortion caused by the thermal expansion upon overheating of the pressure tube and greater than the minimum gap required for heat shiels between the pressure tube and the pressure tube guide pipe during usual operation. In this way, even if such an accident as can not using a coolant cooling device comprising power driven equipment should occur in the pressure tube type reactor, the rise in the temperature of the reactor core can be retarded to obtain a margin with time. (Kamimura, M.)

  10. PEG Tube Placement

    Directory of Open Access Journals (Sweden)

    Saptarshi Biswas

    2014-01-01

    Full Text Available Percutaneous endoscopic gastrostomy (PEG has been used for providing enteral access to patients who require long-term enteral nutrition for years. Although generally considered safe, PEG tube placement can be associated with many immediate and delayed complications. Buried bumper syndrome (BBS is one of the uncommon and late complications of percutaneous endoscopic gastrostomy (PEG placement. It occurs when the internal bumper of the PEG tube erodes into the gastric wall and lodges itself between the gastric wall and skin. This can lead to a variety of additional complications such as wound infection, peritonitis, and necrotizing fasciitis. We present here a case of buried bumper syndrome which caused extensive necrosis of the anterior abdominal wall.

  11. Are we fearful of tubeless percutaneous nephrolithotomy? Assessing the need for tube drainage following percutaneous nephrolithotomy

    Directory of Open Access Journals (Sweden)

    Joel E Abbott

    2016-01-01

    Conclusion: Tubeless and totally tubeless PCNL demonstrates equivalent outcomes in the properly selected patient group when compared to PCNL performed with a nephrostomy tube. Although this is not the first study to demonstrate this, a large majority of urologists continue standard nephrostomy placement after PCNL. More studies are needed that demonstrate safety of this practice to shift the pendulum of care. Thus, tubeless and totally tubeless PCNL can be performed safely and effectively, which has previously been shown to improve cost, patient pain profiles, and length of hospitalization.

  12. Everything is ok on YouTube! Quality assessment of YouTube videos on the topic of phacoemulsification in eyes with small pupil.

    Science.gov (United States)

    Aykut, Aslan; Kukner, Amber Senel; Karasu, Bugra; Palancıglu, Yeliz; Atmaca, Fatih; Aydogan, Tumay

    2018-01-22

    Usage of YouTube as an educational tool is gaining attention in academic research. To date, there has been no study on the content and quality of eye surgery videos on YouTube. The aim of this study was to analyze YouTube videos on phacoemulsification in eyes with small pupil. We searched for the phrases "small pupil cataract surgery," "small pupil phacoemulsification," "small pupil cataract surgery complications," and "small pupil phacoemulsification complications" in January 2015. Each resulting video was evaluated by all authors, and Krippendorff's alpha was calculated to measure agreement. Videos were classified according to pupil size (small/very small) in the beginning of the surgery, and whether pupillary diameter was large enough to continue surgery safely after pupillary dilation by the surgeon in the video (safe/not safe). Methods of dilatation were also analyzed. Any stated ocular comorbidity or surgical complications were noted. A total of 96 videos were reviewed. No mechanical intervention for pupillary dilatation was performed in 46 videos. Fifty-eight operated eyes had no stated ocular comorbidity. Ninety-five operations ended successfully without major complication. There was fair agreement between the evaluators regarding pupil sizes (Kα = 0.670) but poor agreement regarding safety (Kα = 0.337). YouTube videos on small pupil phacoemulsification have low complication rates when compared to the literature, although no reliable mechanical dilatation methods are used in almost half of these videos. Until YouTube's place in e-learning becomes clearer, we suggest that viewers be cautious regarding small pupil phacoemulsification videos on YouTube.

  13. Tube plug

    International Nuclear Information System (INIS)

    Zafred, P. R.

    1985-01-01

    The tube plug comprises a one piece mechanical plug having one open end and one closed end which is capable of being inserted in a heat exchange tube and internally expanded into contact with the inside surface of the heat exchange tube for preventing flow of a coolant through the heat exchange tube. The tube plug also comprises a groove extending around the outside circumference thereof which has an elastomeric material disposed in the groove for enhancing the seal between the tube plug and the tube

  14. Anti-corrosive Effects of Multi-Walled Carbon Nano Tube and Zinc Particle Shapes on Zinc Ethyl Silicate Coated Carbon Steel

    Energy Technology Data Exchange (ETDEWEB)

    Jang, JiMan; Shon, MinYoung; Kwak, SamTak [Pukyong National University, Busan (Korea, Republic of)

    2016-01-15

    Zinc ethyl silicate coatings containing multi walled carbon nanotubes (MWCNTs) were prepared, to which we added spherical and flake shaped zinc particles. The anti-corrosive effects of MWCNTs and zinc shapes on the zinc ethyl silicate coated carbon steel was examined, using electrochemical impedance spectroscopy and corrosion potential measurement. The results of EIS and corrosion potential measurement showed that the zinc ethyl silicate coated with flake shaped zinc particles and MWCNT showed lesser protection to corrosion. These outcomes were in agreement with previous results of corrosion potential and corrosion occurrence.

  15. Code Assessment of SPACE 2.19 using LSTF Steam Generator Tube Rupture Test

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Minhee; Kim, Seyun [KHNP CRI, Daejeon (Korea, Republic of)

    2016-10-15

    The SPACE is a best estimated two-phase three-field thermal-hydraulic analysis code used to analyze the safety and performance of pressurized water reactors. As a result of the development, the 2.19 version of the code was released through the successive various verification and validation works. The present work is on the line of expanding the work by Kim et al. In this study, results produced by the SPACE 2.19 code were compared with the experimental data from JAERI's LSTF Test Run LSTF SB-SG-06 experiment simulating a Steam Generator Tube Rupture (SGTR) transient. In order to identify the predictability of SPACE 2.19, the LSTF steam generator tube rupture test was simulated. To evaluate the computed results, LSTF SB-SG-06 test data simulating the SGTR and the RELAP5/ MOD3.1 are used. The calculation results indicate that the SPACE 2.19 code predicted well the sequence of events and the major phenomena during the transient, such as the asymmetric loop behavior, reactor coolant system cooldown and heat transfer by natural circulation, the primary and secondary system depressurization by the pressurizer auxiliary spray and the steam dump using the intact loop steam generator relief valve.

  16. Optical Fiber Demodulation System with High Performance for Assessing Fretting Damage of Steam Generator Tubes

    Directory of Open Access Journals (Sweden)

    Peijian Huang

    2018-01-01

    Full Text Available In order to access the fretting damage of the steam generator tube (SGT, a fast fiber Fabry-Perot (F-P non-scanning correlation demodulation system based on a super luminescent light emitting diode (SLED was performed. By demodulating the light signal coming out from the F-P force sensor, the radial collision force between the SGT and the tube support plate (TSP was interrogated. For higher demodulation accuracy, the effects of the center wavelength, bandwidth, and spectrum noise of SLED were discussed in detail. Specially, a piezoelectric ceramic transducer (PZT modulation method was developed to get rid of the interference of mode coupling induced by different types of fiber optics in the demodulation system. The reflectivity of optical wedge and F-P sensor was optimized. Finally, the demodulation system worked well in a 1:1 steam generator test loop and successfully demodulated a force signal of 32 N with a collision time of 2 ms.

  17. Experimental study of heat transfer to the N2O4 dissociating coolant in the circular tube with variable heat load on the wall

    International Nuclear Information System (INIS)

    Golovnya, V.N.; Kolykhan, L.I.

    1983-01-01

    The results of the experimental study of heat transfer to N 2 O 4 dissociating coolant with a sinusoidal law of heat flux density variation by length are presented. The heat transfer process has been studied at subcritical and supercritical parameters and different substance aggregation states. Maximum error of heat transfer coefficient determination don't exceed 15%. The esimation of the effect of variable heat load on heat transfer has been condUcted by comparison of experimental data on the Nusselt number change along the tube length with that calculated using conventional relations for the conditions of uniform heat release. It is shown that heat transfer is enhanced in the region of heat load qsub(c) growth while its intensity is decreased in the region of heat flux reduction. The quantitative effect of qsub(c) variation on heat transfer can be regarded for by the method of superpositions

  18. The impact of a chest tube management protocol on the outcome of trauma patients with tube thoracostomy.

    Science.gov (United States)

    de Abreu, Emanuelle Maria Sávio; Machado, Carla Jorge; Pastore Neto, Mario; de Rezende Neto, João Baptista; Sanches, Marcelo Dias

    2015-01-01

    to investigate the effect of standardized interventions in the management of tube thoracostomy patients and to assess the independent effect of each intervention. A chest tube management protocol was assessed in a retrospective cohort study. The tube thoracostomy protocol (TTP) was implemented in August 2012, and consisted of: antimicrobial prophylaxis, chest tube insertion in the operating room (OR), admission post chest tube thoracostomy (CTT) in a hospital floor separate from the emergency department (ED), and daily respiratory therapy (RT) sessions post-CTT. The inclusion criteria were, hemodynamic stability, patients between the ages of 15 and 59 years, and injury severity score (ISS) chest wall, lung, and pleura. During the study period 92 patients were managed according to the standardized protocol. The outcomes of those patients were compared to 99 patients treated before the TTP. Multivariate logistic regression analysis was performed to assess the independent effect of each variable of the protocol on selected outcomes. Demographics, injury severity, and trauma mechanisms were similar among the groups. As expected, protocol compliance increased after the implementation of the TTP. There was a significant reduction (pchest tube days. Respiratory therapy was independently linked to significant reduction (pchest tube insertion was associated with significant (ptrauma patients.

  19. Gastrostomy Tube (G-Tube)

    Science.gov (United States)

    ... any of these problems: a dislodged tube a blocked or clogged tube any signs of infection (including redness, swelling, or warmth at the tube site; discharge that's yellow, green, or foul-smelling; fever) excessive bleeding or drainage from the tube site severe abdominal pain lasting ...

  20. TRACE assessment on local condensation heat transfer in presence of non-condensable gas inside a vertical tube

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yong Jin; Ahn, Seung Hoon; Kim, Kap; Kim, Hho Jung [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2009-07-01

    TRACE assessment was performed to investigate local condensation heat transfer coefficients in the presence of a noncondensable gas inside a vertical tube. The data obtained from pure steam and steam/nitrogen mixture condensation experiments were compared to study the effects of noncondensable nitrogen gas on the annular film condensation phenomena. The condenser tube had a small inner diameter of 13mm (about 1/2-in.) and this experiment had been performed to prove the effectiveness of the a Passive Residual Heat Removal System (PRHRS) of SMART (System-integrated Modular Advanced ReacTor), which is a small modular integral-type pressurized water reactor that is developed for the dual purposes of seawater desalination and small-scaled power generation. In the case of nitrogen presence, TRACE results show the converged results but the prediction is different from experimental data. The candidate reasons can be focused on several models, such as the film thickness calculation, surface area, and condensation heat transfer correlations, etc. In the case of pure steam condensation case, TRACE results shows large oscillations and do not converge. This should be investigated in detail to identify the reason. Until now, the oscillation in thermal hydraulic parameters results from the film thickness calculation and surface area calculation. For future works, the whole sets of the experiment will be assessed and the improvement of TRACE will be performed.

  1. TRACE assessment on local condensation heat transfer in presence of non-condensable gas inside a vertical tube

    International Nuclear Information System (INIS)

    Cho, Yong Jin; Ahn, Seung Hoon; Kim, Kap; Kim, Hho Jung

    2009-01-01

    TRACE assessment was performed to investigate local condensation heat transfer coefficients in the presence of a noncondensable gas inside a vertical tube. The data obtained from pure steam and steam/nitrogen mixture condensation experiments were compared to study the effects of noncondensable nitrogen gas on the annular film condensation phenomena. The condenser tube had a small inner diameter of 13mm (about 1/2-in.) and this experiment had been performed to prove the effectiveness of the a Passive Residual Heat Removal System (PRHRS) of SMART (System-integrated Modular Advanced ReacTor), which is a small modular integral-type pressurized water reactor that is developed for the dual purposes of seawater desalination and small-scaled power generation. In the case of nitrogen presence, TRACE results show the converged results but the prediction is different from experimental data. The candidate reasons can be focused on several models, such as the film thickness calculation, surface area, and condensation heat transfer correlations, etc. In the case of pure steam condensation case, TRACE results shows large oscillations and do not converge. This should be investigated in detail to identify the reason. Until now, the oscillation in thermal hydraulic parameters results from the film thickness calculation and surface area calculation. For future works, the whole sets of the experiment will be assessed and the improvement of TRACE will be performed

  2. Strong, corrosion-resistant aluminum tubing

    Science.gov (United States)

    Reed, M. W.; Adams, F. F.

    1980-01-01

    When aluminum tubing having good corrosion resistance and postweld strength is needed, type 5083 alloy should be considered. Chemical composition is carefully controlled and can be drawn into thin-wall tubing with excellent mechanical properties. Uses of tubing are in aircraft, boats, docks, and process equipment.

  3. Development of assessment methodology for locally wall-thinned pipe under combined loading

    International Nuclear Information System (INIS)

    Shim, Do Jun; Kim, Yun Jae; Kim, Young Jin; Park, Chi Yong

    2005-01-01

    Recently authors have proposed a new method to estimate failure strength of a pipe with local wall thinning subject to either internal pressure or global bending. The proposed method was based on the equivalent stress averaged over the minimum ligament in the locally wall thinned region, and the simple scheme to estimate the equivalent stress in the minimum ligament was proposed, based on the reference stress concept. This paper extends the new method to combined internal pressure and global bending. The proposed method is validated against FE results for various geometries of local wall thinning under combined loading. The effect of internal pressure is also investigated in the present study. Comparison of maximum moments, predicted according to the proposed method, with published full-scale pipe test data for locally wall-thinned pipes under combined internal pressure and global bending, shows good agreement

  4. Experimental assessment of dry stone retaining wall stability on a rigid foundation

    OpenAIRE

    Villemus , B.; Morel , J.C.; Boutin , C.

    2007-01-01

    International audience; Dry stone masonry retaining walls are present in the majority of mountainous areas all around the world, but the technique is marginal today in developed countries. The emergence of the concept of sustainable development calls for renewed use of this technique, both for the repair of existing retaining walls and the building of new ones. The objective of this research was to seek the knowledge necessary to ensure the stability of these structures, using experimental in...

  5. Performance Assessment in a Heat Exchanger Tube with Opposite/Parallel Wing Twisted Tapes

    Directory of Open Access Journals (Sweden)

    S. Eiamsa-ard

    2015-02-01

    Full Text Available The thermohydraulic performance in a tube containing a modified twisted tape with alternate-axes and wing arrangements is reported. This work aims to investigate the effects of wing arrangements (opposite (O and parallel (P wings at different wing shapes (triangle (Tri, rectangular (Rec, and trapezoidal (Tra wings and on the thermohydraulic performance characteristics. The obtained results show that wing twisted tapes with all wing shape arrangements (O-Tri/O-Rec/O-Tra/P-Tri/P-Rec/P-Tra give superior thermohydraulic performance and heat transfer rate to the typical twisted tape. In addition, the tapes with opposite wing arrangement of O-Tra, O-Rec, and O-Tri give superior thermohydraulic performances to those with parallel wing arrangement of P-Tra, P-Rec, and P-Tri around 2.7%, 3.5%, and 3.2%, respectively.

  6. ['FLEXIBLE WALLS' IN HOSPITALS - ASSESSING THE 'VALUE' OF SOCIAL IMPACT ON ARCHITECTURE].

    Science.gov (United States)

    Tal, Orna; Tal, Shy-Lee

    2018-05-01

    : The development of hospital architecture is influenced by social trends, with mutual influence. Architecture enables 'organic-design' that leads to development, growth and adaptation of the structure to changing functions. A literature review reveals different perceptions of the flexibility of adapting hospital structure to changing needs, focusing on external forces pressures (expensive technologies, budgetary constraints limiting innovation implementation and regulatory barriers), as well as patients' demands. The degree of contribution of structural changes to the measured or perceived benefit to the patient and staff, has not yet been fully assessed. Expressions of this benefit are infection-control and increasing operational efficiency by energy saving and sustainability. To examine workers' perceptions towards value-based-architecture in relation to the patient or staff in a hospital setting. A survey was conducted among health care workers who underwent management training, using a structured questionnaire. Sixty responders ranked hospital leadership and relevant professionals (engineers and architects) as key players in the decision to change architecture in a hospital; economists, doctors and nurses were ranked as less important, while patients and families were ranked the lowest. Among the factors that contribute to the 'value' of the decision were the agility to adapt to emergency, and to changing morbidity trends in an efficient way. Factors ranked as being of medium importance were the contribution to hospital profitability and, to a lesser extent, the contribution to branding and improved service. 'Flexible walls' (shifting rooms between departments according to clinical need) can provide a response to morbidity changes. Hospital workers can play a role in the process of value-based architecture, thereby improving decisions concerning hospital construction and increasing their commitment to additional quality processes.

  7. Grooved tube plug rolls in

    International Nuclear Information System (INIS)

    Krausser, P.

    1991-01-01

    The removable plugs used to date by the Power Generation Group (KWU) of Siemens to seal defective steam generator tubes have a good track record. Their sealing principle is based on the elastic tensioning of three seal disks against the inside wall of the tube. Now a further removable plug is available -a roll-in plug with a metal-coated surface. It is particularly suitable for use in the roller-expanded zone of the tubes at the tube sheet. The plugs can be used in both Siemens-KWU steam generators and in steam generators manufactured in compliance with the guidelines of the ASME Code. (author)

  8. Theoretical-experimental assessment of the variables affecting fretting of Atucha I nuclear power plant utility steam generators tubes

    International Nuclear Information System (INIS)

    Kulichevsky, Raul M.

    1995-01-01

    Fretting wear of Steam Generator tubes caused by flow induced vibrations generates uncertainty on their integrity. The knowledge of the controlling variables of the wear process may give a criterion to evaluate the tubes residual life. Information on vibratory response and dynamic interaction between tubes and their supports are prerequisites for understanding the relationship between fretting wear and tube vibration. Experimental results of the vibratory response of an Atucha-I nuclear power plant type U-tube, the influence of tube/support clearance on this response and a study of tube/support dynamic interaction, which allow the verification of a finite element model of this type of tubes, are presented in this work. Also wear results for the Incoloy 800/DIN 1.4550 austenitic stainless steel pair of materials and a first evaluation of the wear constant of this pair are presented. (author)

  9. Quantifying Intracranial Aneurysm Wall Permeability for Risk Assessment Using Dynamic Contrast-Enhanced MRI: A Pilot Study.

    Science.gov (United States)

    Vakil, P; Ansari, S A; Cantrell, C G; Eddleman, C S; Dehkordi, F H; Vranic, J; Hurley, M C; Batjer, H H; Bendok, B R; Carroll, T J

    2015-05-01

    Pathological changes in the intracranial aneurysm wall may lead to increases in its permeability; however the clinical significance of such changes has not been explored. The purpose of this pilot study was to quantify intracranial aneurysm wall permeability (K(trans), VL) to contrast agent as a measure of aneurysm rupture risk and compare these parameters against other established measures of rupture risk. We hypothesized K(trans) would be associated with intracranial aneurysm rupture risk as defined by various anatomic, imaging, and clinical risk factors. Twenty-seven unruptured intracranial aneurysms in 23 patients were imaged with dynamic contrast-enhanced MR imaging, and wall permeability parameters (K(trans), VL) were measured in regions adjacent to the aneurysm wall and along the paired control MCA by 2 blinded observers. K(trans) and VL were evaluated as markers of rupture risk by comparing them against established clinical (symptomatic lesions) and anatomic (size, location, morphology, multiplicity) risk metrics. Interobserver agreement was strong as shown in regression analysis (R(2) > 0.84) and intraclass correlation (intraclass correlation coefficient >0.92), indicating that the K(trans) can be reliably assessed clinically. All intracranial aneurysms had a pronounced increase in wall permeability compared with the paired healthy MCA (P risk in anatomic (P = .02) and combined anatomic/clinical (P = .03) groups independent of size. We report the first evidence of dynamic contrast-enhanced MR imaging-modeled contrast permeability in intracranial aneurysms. We found that contrast agent permeability across the aneurysm wall correlated significantly with both aneurysm size and size-independent anatomic risk factors. In addition, K(trans) was a significant and size-independent predictor of morphologically and clinically defined high-risk aneurysms. © 2015 by American Journal of Neuroradiology.

  10. FIELD DEMONSTRATION OF INNOVATIVE CONDITION ASSESSMENT TECHNOLOGIES FOR WATER MAINS: ACOUSTIC PIPE WALL ASSESSMENT, INTERNAL INSPECTION, AND EXTERNAL INSPECTIONVOLUME 1: TECHNICAL REPORT AND VOLUME 2: APPENDICES

    Science.gov (United States)

    Nine pipe wall integrity assessment technologies were demonstrated on a 76-year-old, 2,057-ft-long portion of a cement-lined, 24-in. cast iron water main in Louisville, KY. This activity was part of a series of field demonstrations of innovative leak detection/location and condi...

  11. Assessment of wall-thinning in carbon steel pipe by using laser-generated guided wave

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Do Yong; Cho, Youn Ho; Lee, Joon Hyun [Pusan National University, School of Mechanical Engineering, Busan (Korea, Republic of)

    2010-10-15

    The objective of this research is to estimate the crack location and size of a carbon steel pipe by using a laser ultrasound guided wave for the wall thinning evaluation of an elbow. The wall thinning of the carbon steel pipe is one of the most serious problems in nuclear power plants, especially the wall thinning of the carbon steel elbow caused by Flow-Accelerated Corrosion (FAC). Therefore, a non-destructive inspection method of elbow is essential for the nuclear power plants to operate safely. The specimens used in this study were carbon steel elbows, which represented the main elements of real nuclear power plants. The shape of the wall thinning was an oval with a width of 120mm, a length of 80mm, and a depth of 5mm. The L(0,1) and L(0,2) modes variation of the ultrasound guided wave signal is obtained from the response of the laser generation/air-coupled detection ultrasonic hybrid system represent the characteristics of the defect. The trends of these characteristics and signal processing were use dto estimate the size and location of wall thinning

  12. Assessment of wall-thinning in carbon steel pipe by using laser-generated guided wave

    International Nuclear Information System (INIS)

    Kim, Do Yong; Cho, Youn Ho; Lee, Joon Hyun

    2010-01-01

    The objective of this research is to estimate the crack location and size of a carbon steel pipe by using a laser ultrasound guided wave for the wall thinning evaluation of an elbow. The wall thinning of the carbon steel pipe is one of the most serious problems in nuclear power plants, especially the wall thinning of the carbon steel elbow caused by Flow-Accelerated Corrosion (FAC). Therefore, a non-destructive inspection method of elbow is essential for the nuclear power plants to operate safely. The specimens used in this study were carbon steel elbows, which represented the main elements of real nuclear power plants. The shape of the wall thinning was an oval with a width of 120mm, a length of 80mm, and a depth of 5mm. The L(0,1) and L(0,2) modes variation of the ultrasound guided wave signal is obtained from the response of the laser generation/air-coupled detection ultrasonic hybrid system represent the characteristics of the defect. The trends of these characteristics and signal processing were use dto estimate the size and location of wall thinning

  13. Experimental assessment of air permeability in a concrete shear wall subjected to simulated seismic loading

    International Nuclear Information System (INIS)

    Girrens, S.P.; Farrar, C.R.

    1991-07-01

    A safety concern for the proposed Special Nuclear Materials Laboratory (SNML) facility at the Los Alamos National Laboratory was air leakage from the facility if it were to experience a design basis earthquake event. To address this concern, a study was initiated to estimate air leakage, driven by wind-generated pressure gradients, from a seismically damaged concrete structure. This report describes a prototype experiment developed and performed to measure the air permeability in a reinforced concrete shear wall, both before and after simulated seismic loading. A shear wall test structure was fabricated with standard 4000-psi concrete mix. Static load-cycle testing was used to simulate earthquake loading. Permeability measurements were made by pressurizing one side of the shear wall above atmospheric conditions and recording the transient pressure decay. As long as the structure exhibited linear load displacement response, no variation in the air permeability was detected. However, experimental results indicate that the air permeability in the shear wall increased by a factor of 40 after the wall had been damaged (cracked). 17 figs., 8 tabs

  14. PRODUCTION OF URANIUM TUBING

    Science.gov (United States)

    Creutz, E.C.

    1958-04-15

    The manufacture of thin-walled uranium tubing by the hot-piercing techique is described. Uranium billets are preheated to a temperature above 780 d C. The heated billet is fed to a station where it is engaged on its external surface by three convex-surfaced rotating rollers which are set at an angle to the axis of the billet to produce a surface friction force in one direction to force the billet over a piercing mandrel. While being formed around the mandrel and before losing the desired shape, the tube thus formed is cooled by a water spray.

  15. Quality assessment of studies on interventional recanalization of fallopian tube in China

    International Nuclear Information System (INIS)

    Lu Liming; Zhou Weisheng; Yan Ying; Zeng Jingchun

    2009-01-01

    Objective: To evaluate the current status of studies on interventional recanalization of fallopian tube. Methods: According to the standard of evidence-based medicine, literatures were analyzed by two readers in three time periods: 1997 to 2000, 2001 to 2004 and 2005 to 2008. Two separate evaluation results were tested by the statistical method Kappa to test its consistency. Scores of clinical controlled trials (CCT) and randomized controlled trials (RCT) were calculated according to Jadad score scale. The accurate criteria of case selection, case exclusion, and effect determination; the method of randomization; the number of samples; the comparability of baseline; the blinded procedure; the therapeutic method; the method of statistical analysis; the follow-up cases; the drop-out cases and the conclusions derivation of RCT and CCT into descriptive analysis were evaluated. Results: One hundred and fifty seven therapeutic articles were searched and 30 RCT and CCT articles (25 RCT and 5 CCT) were analyzed. The Kappa value was 0.85 and P<0.05 indicating that the evaluation was in good consistency. 2, 15 and 8 RCT received 0 point, 1 point and 2 points respectively in Jadad score scale. RCT and CCT contained 9 articles (30.0%) fulfilled the accurate criteria of case selection and exclusion; 12 articles (40.0%) met the accurate criteria of effect determination; 4 articles (13.3%) utilized the definite method of randomization; 27 articles (90.0%) had the number of sample beyond 60; 14 articles (46.7%) met the baseline comparability; only 1 article (3.3%) used the single-blinded method, 17 articles (56.7%) utilized the method of statistical analysis; 13 (43.3%) mentioned follow-up in articles; 4 (13.3%) mentioned drop-out cases in the articles and 14 (46.7%) articles had the conclusions derived by considering the statistical significance and clinical significance. Conclusion: The quality of studies on interventional recanalization of fallopian tube is poor and could not

  16. Assessment of left ventricular wall motion and function by cross-sectional echocardiography

    International Nuclear Information System (INIS)

    Ono, Akifumi; Hirata, Shunkichi; Ishikawa, Kyozo

    1982-01-01

    The clinical efficacy of cross-sectional echocardiography (CSE) was evaluated with M-mode echocardiography and radionuclide cardioangiography (RCG) in 50 cases including 30 patients with myocardial infarction. Segmental wall motion by CSE was highly correlated with segmental wall motion and left ventricular ejection fraction by RCG (r = 0.89 in the former, r = -0.84 in the latter). On the other hand, the left ventricular ejection fraction by M-mode echocardiography revealed a fairly well correlation with that by RCG ( r = 0.68). These results suggest that, as compared with RCG, CSE is quite useful in an evaluation of left ventricular function and in a detection of segmental wall motion abnormalities. (author)

  17. An investigation on vulnerability assessment of steel structures with thin steel shear wall through development of fragility curves

    OpenAIRE

    Mohsen Gerami; Saeed Ghaffari; Amir Mahdi Heidari Tafreshi

    2017-01-01

    Fragility curves play an important role in damage assessment of buildings. Probability of damage induction to the structure against seismic events can be investigated upon generation of afore mentioned curves. In current research 360 time history analyses have been carried out on structures of 3, 10 and 20 story height and subsequently fragility curves have been adopted. The curves are developed based on two indices of inter story drifts and equivalent strip axial strains of the shear wall. T...

  18. Cooling performance assessment of horizontal earth tube system and effect on planting in tropical greenhouse

    International Nuclear Information System (INIS)

    Mongkon, S.; Thepa, S.; Namprakai, P.; Pratinthong, N.

    2014-01-01

    Graphical abstract: - Highlights: • The cooling ability of HETS is studied for planting in tropical greenhouse. • The effective of system was moderate with COP more than 2.0. • Increasing diameter and air velocity increase COP more than other parameters. • The plant growth with HETS was significantly better than no-HETS plant. - Abstract: The benefit of geothermal energy is used by the horizontal earth tube system (HETS); which is not prevalent in tropical climate. This study evaluated geothermal cooling ability and parameters studied in Thailand by mathematical model. The measurement of the effect on plant cultivation was carried out in two identical greenhouses with 30 m 2 of greenhouse volume. The HETS supplied cooled air to the model greenhouse (MGH), and the plant growth results were compared to the growth results of a conventional greenhouse (CGH). The prediction demonstrated that the coefficient of performance (COP) in clear sky day would be more than 2.0 while in the experiment it was found to be moderately lower. The parameters study could be useful for implementation of a system for maximum performance. Two plants Dahlias and head lettuce were grown satisfactory. The qualities of the plants with the HETS were better than the non-cooled plants. In addition, the quality of production was affected by variations of microclimate in the greenhouses and solar intensity throughout the cultivation period

  19. Perfusion CT assessment of the colon and rectum: Feasibility of quantification of bowel wall perfusion and vascularization

    International Nuclear Information System (INIS)

    Khan, Sairah; Goh, Vicky; Tam, Emily; Wellsted, David; Halligan, Steve

    2012-01-01

    The aim was to determine the feasibility of vascular quantification of the bowel wall for different anatomical segments of the colorectum. Following institutional ethical approval and informed consent, 39 patients with colorectal cancer underwent perfusion CT. Blood flow (BF), blood volume (BV), mean transit time (MTT), and permeability surface area product (PS) were assessed for different segments of the colorectum: ascending, transverse, descending colon, sigmoid, or rectum, that were distant from the tumor, and which were proven normal on contemporary colonoscopy, and subsequent imaging and clinical follow up. Mean (SD) for BF, BV, MTT and PS for the different anatomical colorectal segments were obtained and compared using a pooled t-test. Significance was at 5%. Assessment was not possible in 9 of 39 (23%) patients as the bowel wall was ≤5 mm precluding quantitative analysis. Forty-four segments were evaluated in the remaining 30 patients. Mean BF was higher in the proximal than distal colon: 24.0 versus 17.8 mL/min/100 g tissue; p = 0.009; BV, MTT and PS were not significantly different; BV: 3.46 versus 3.15 mL/100 g tissue, p = 0.45; MTT: 15.1 versus 18.3 s; p = 0.10; PS: 6.84 versus 8.97 mL/min/100 tissue, p = 0.13, respectively. In conclusion, assessment of bowel wall perfusion may fail in 23% of patients. The colorectum demonstrates segmental differences in perfusion.

  20. Assessment of RELAP5/MOD3 with condensation experiment for pure steam condensation in a vercal tube

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Jae; No, Hee Cheon [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1999-12-31

    The film condensation models in RELAP5/MOD3.1 and RELAP5/MOD3.2 are assessed with the data of experiment performed in the scaled down condensation experimental facility with a single vertical tube of inner diameter of 46 mm in the range of pressure 0.1 {approx} 7.5 MPa for the PSCS(Passive Secondary Condenser System). Both MOD3.1 and MOD3.2 don`t shows any reliable predictions of the experimental data. The RELAP5/MOD3.1 overpredicts the heat transfer coefficients of experiment, whereas the RELAP5/MOD3.2 underpredicts those data. It is recommended that the film condensation model in RELAP5/MOD3.2 should be modified to have a larger heat transfer coefficient than those of the present model to give the reliable predictions. 7 refs., 6 figs., 1 tab. (Author)

  1. Assessment of RELAP5/MOD3 with condensation experiment for pure steam condensation in a vercal tube

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Jae; No, Hee Cheon [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1998-12-31

    The film condensation models in RELAP5/MOD3.1 and RELAP5/MOD3.2 are assessed with the data of experiment performed in the scaled down condensation experimental facility with a single vertical tube of inner diameter of 46 mm in the range of pressure 0.1 {approx} 7.5 MPa for the PSCS(Passive Secondary Condenser System). Both MOD3.1 and MOD3.2 don`t shows any reliable predictions of the experimental data. The RELAP5/MOD3.1 overpredicts the heat transfer coefficients of experiment, whereas the RELAP5/MOD3.2 underpredicts those data. It is recommended that the film condensation model in RELAP5/MOD3.2 should be modified to have a larger heat transfer coefficient than those of the present model to give the reliable predictions. 7 refs., 6 figs., 1 tab. (Author)

  2. Comparison of Enzymatic Assay and Multiple Tube Fermentation Technique in the Assessment of Microbial Quality of the Karoon River

    Directory of Open Access Journals (Sweden)

    Mahnaz Nikaeen

    2010-09-01

    Full Text Available Microbiological monitoring of surface waters designated for use as drinking water is essential by water utilities for the design and operation of drinking water treatment plants. Enzymatic assays have been applied as a rapid alternative approach to assess the microbiological quality of freshwater. In this study, the LMX broth (LMX as an enzymatic assay was compared with the standard method of multiple tube fermentation technique (MTF for the microbial monitoring of the Karoon River. Enumeration of total coliforms and E. coli averaged 9928 and 6684 MPN/ 100 ml by the LMX and 7564 and 6546 MPN/ 100 ml for the MTF, respectively. This difference was statistically significant for TC but the overall analysis revealed no difference between E. coli recoveries on LMX and MTF. In conclusion, LMX can be used for the enumeration of coliforms and E. coli in surface waters as it is less lobar-intensive, yields faster result, and simultaneously detects both total coliforms and E. coli.

  3. [Assessment of central hemodynamic properties of the arterial wall in women with previous preeclampsia].

    Science.gov (United States)

    Polónia, Jorge; Olival, Catarina; Ribeiro, Sílvia; Silva, José A; Barbosa, Loide

    2014-06-01

    We investigated viscoelastic properties of the arterial wall in women with previous preeclampsia (PE) compared to those with normal pregnancy (NP). In a cross-sectional study 45 women with previous PE and 55 with NP were included, matched for age (PE 38±6 vs. NP 38±5 years, NS) and body mass index: (PE 25±4 vs. NP 26±4 kg/m(2), NS) studied, respectively, 76±34 and 86±48 months after delivery. We assessed arterial distensibility - pulse wave velocity (PWV, Complior) and reflected waves (augmentation pressure [AP], mmHg) and augmentation index (AIx) - in the central pressure wave and blood pressure (BP) on 24-h ambulatory BP monitoring (ABPM). PE showed higher (p<0.01) peripheral systolic blood pressure (SBP): PE 131±18 vs. NP 121±19, and central SBP: PE 122±18 vs. NP 110±19 mmHg, with less amplification of central-peripheral pressure: PE 10±4 vs. NP 12±5, p=0.041, and higher (p<0.05) AP: PE 10±3 vs. NP 8±2, and AIx: PE 26±5 vs. NP 20±5 mmHg, but PE and NP did not differ in pulse wave velocity. On ABPM, PE (n=39) vs. NP (n=33) had higher nighttime SBP: PE 121±10 vs. NP 108±10 mmHg and lower percentage nocturnal SBP fall: PE 11±6 vs. NP 18±11%, both p<0.02. During follow-up, the need for antihypertensive medication was seven times higher in PE than in NP. Women with previous PE have a greater risk of hypertension, higher nighttime BP values, blunted nocturnal BP fall and changes in central pressure suggestive of increased reflected waves and peripheral vascular resistance. These factors may contribute to their higher cardiovascular risk after pregnancy. Copyright © 2013 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

  4. Assessment of an organ‐based tube current modulation in thoracic computed tomography

    Science.gov (United States)

    Sugai, Mai; Toyoda, Asami; Koshida, Haruka; Sakuta, Keita; Takata, Tadanori; Koshida, Kichiro; Iida, Hiroji; Matsui, Osamu

    2012-01-01

    Recently, specific computed tomography (CT) scanners have been equipped with organ‐based tube current modulation (TCM) technology. It is possible that organ‐based TCM will replace the conventional dose‐reduction technique of reducing the effective milliampere‐second. The aim of this study was to determine if organ‐based TCM could reduce radiation exposure to the breasts without compromising the image uniformity and beam hardening effect in thoracic CT examinations. Breast and skin radiation doses and the absorbed radiation dose distribution within a single section were measured with an anthropomorphic phantom and radiophotoluminescent glass dosimeters using four approaches to thoracic CT (reference, organ‐based TCM, copper shielding, and the combination of the above two techniques, hereafter referred to as the combination technique). The CT value and noise level were measured using the same calibration phantom. Organ‐based TCM and copper shielding reduced radiation doses to the breast by 23.7% and 21.8%, respectively. However, the CT value increased, especially in the anterior region, using copper shielding. In contrast, the CT value and noise level barely increased using organ‐based TCM. The combination technique reduced the radiation dose to the breast by 38.2%, but greatly increased the absorbed radiation dose from the central to the posterior regions. Moreover, the CT value increased in the anterior region and the noise level increased by more than 10% in the entire region. Therefore, organ‐based TCM can reduce radiation doses to breasts with only small increases in noise levels, making it preferable for specific groups of patients, such as children and young women. PACS numbers: 87.53.Bn; 87.57.Q‐; 87.57.qp PMID:22402390

  5. Assessment of an organ-based tube current modulation in thoracic computed tomography.

    Science.gov (United States)

    Matsubara, Kosuke; Sugai, Mai; Toyoda, Asami; Koshida, Haruka; Sakuta, Keita; Takata, Tadanori; Koshida, Kichiro; Iida, Hiroji; Matsui, Osamu

    2012-03-08

    Recently, specific computed tomography (CT) scanners have been equipped with organ-based tube current modulation (TCM) technology. It is possible that organ-based TCM will replace the conventional dose-reduction technique of reducing the effective milliampere-second. The aim of this study was to determine if organ-based TCM could reduce radiation exposure to the breasts without compromising the image uniformity and beam hardening effect in thoracic CT examinations. Breast and skin radiation doses and the absorbed radiation dose distribution within a single section were measured with an anthropomorphic phantom and radiophotoluminescent glass dosimeters using four approaches to thoracic CT (reference, organ-based TCM, copper shielding, and the combination of the above two techniques, hereafter referred to as the combination technique). The CT value and noise level were measured using the same calibration phantom. Organ-based TCM and copper shielding reduced radiation doses to the breast by 23.7% and 21.8%, respectively. However, the CT value increased, especially in the anterior region, using copper shielding. In contrast, the CT value and noise level barely increased using organ-based TCM. The combination technique reduced the radiation dose to the breast by 38.2%, but greatly increased the absorbed radiation dose from the central to the posterior regions. Moreover, the CT value increased in the anterior region and the noise level increased by more than 10% in the entire region. Therefore, organ-based TCM can reduce radiation doses to breasts with only small increases in noise levels, making it preferable for specific groups of patients, such as children and young women.

  6. Correlation between posterior vaginal wall defects assessed by clinical examination and by defecography

    NARCIS (Netherlands)

    Groenendijk, Annette G.; van der Hulst, Victor P.; Birnie, Erwin; Bonsel, Gouke J.

    2008-01-01

    To estimate the accuracy of clinical examination and the indications for defecography in patients with primary posterior wall prolapse. Fifty-nine patients with primary pelvic organ prolapse were evaluated with a questionnaire, clinical examination and defecography. Defecography was used as

  7. Uncertainty assessment of a dike with an anchored sheet pile wall using FEM

    NARCIS (Netherlands)

    Rippi, Aikaterini; Nuttall, Jonathan; Teixeira, Ana; Schweckendiek, T.; Lang, M.; Klijn, F.; Samuels, P.

    2016-01-01

    The Dutch design codes for the dikes with retaining walls rely on Finite Element Analysis (FEM) in combination with partial safety factors. However, this can lead to conservative designs. For this reason, in this study, a reliability analysis is carried out with FEM calculations aiming to

  8. An assessment of CFD-based wall heat transfer models in piston engines

    Energy Technology Data Exchange (ETDEWEB)

    Sircar, Arpan [Pennsylvania State Univ., University Park, PA (United States); Paul, Chandan [Pennsylvania State Univ., University Park, PA (United States); Ferreyro-Fernandez, Sebastian [Pennsylvania State Univ., University Park, PA (United States); Imren, Abdurrahman [Pennsylvania State Univ., University Park, PA (United States); Haworth, Daniel C [Pennsylvania State Univ., University Park, PA (United States)

    2017-04-26

    The lack of accurate submodels for in-cylinder heat transfer has been identified as a key shortcoming in developing truly predictive, physics-based computational fluid dynamics (CFD) models that can be used to develop combustion systems for advanced high-efficiency, low-emissions engines. Only recently have experimental methods become available that enable accurate near-wall measurements to enhance simulation capability via advancing models. Initial results show crank-angle dependent discrepancies with respect to previously used boundary-layer models of up to 100%. However, available experimental data is quite sparse (only few data points on engine walls) and limited (available measurements are those of heat flux only). Predictive submodels are needed for medium-resolution ("engineering") LES and for unsteady Reynolds-averaged simulations (URANS). Recently, some research groups have performed DNS studies on engine-relevant conditions using simple geometries. These provide very useful data for benchmarking wall heat transfer models under such conditions. Further, a number of new and more sophisticated models have also become available in the literature which account for these engine-like conditions. Some of these have been incorporated while others of a more complex nature, which include solving additional partial differential equations (PDEs) within the thin boundary layer near the wall, are underway. These models will then be tested against the available DNS/experimental data in both SI (spark-ignition) and CI (compression-ignition) engines.

  9. Fracture toughness determination in steam generator tubes

    International Nuclear Information System (INIS)

    Bergant M; Yawny, A; Perez Ipina, J

    2012-01-01

    The assessment of the structural integrity of steam generator tubes in nuclear power plants deserved increasing attention in the last years due to the negative impact related to their failures. In this context, elastic plastic fracture mechanics (EPFM) methodology appears as a potential tool for the analysis. The application of EPFM requires, necessarily, knowledge of two aspects, i.e., the driving force estimation in terms of an elastic plastic toughness parameter (e.g., J) and the experimental measurement of the fracture toughness of the material (e.g., the material J-resistance curve). The present work describes the development of a non standardized experimental technique aimed to determine J-resistance curves for steam generator tubes with circumferential through wall cracks. The tubes were made of Incoloy 800 (Ni: 30.0-35.0; Cr: 19.0-23.0; Fe: 35.5 min, % in weight). Due to its austenitic microstructure, this alloy shows very high toughness and is widely used in applications where a good corrosion resistance in aqueous environment or an excellent oxidation resistance in high temperature environment is required. Finally, a procedure for the structural integrity analysis of steam generator tubes with crack-like defects, based on a FAD diagram (Failure Assessment Diagram), is briefly described (author)

  10. Combined application of GPR and ERT for the assessment of a wall structure at the Heptapyrgion fortress (Thessaloniki, Greece)

    Science.gov (United States)

    Angelis, Dimitrios; Tsourlos, Panagiotis; Tsokas, Gregory; Vargemezis, George; Zacharopoulou, Georgia; Power, Christopher

    2018-05-01

    Non-destructive investigation of monuments can be an extremely valuable tool to evaluate potential structural defects and assist in developing any restoration plans. In this work, both Ground Penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT) techniques were applied to a tower wall of the Heptapyrgion fortress located in Thessaloniki, Greece, which was facing significant moisture problems. GPR cross sections, mainly obtained with a 500 MHz centre frequency antenna, and ERT profiles were collected along the same survey grid on the tower wall. The gprMax numerical solver was used for the GPR forward modelling. In addition, an auxiliary program was used to design and import into gprMax complicated structures and this allowed to simulate more realistically the wall defects and moisture. The GPR simulator was used to assess and optimize the field data acquisition and processing parameters, and to assist in interpreting the GPR cross sections. The ERT sections were inverted as individual 2D lines and also, as a full 3D dataset. The final GPR and ERT data were jointly interpreted in view of the studied problem as results of both methods are highly correlated. A high moisture content area at the eastern part of the wall was identified in both GPR and ERT data, along with the interface between different phases of construction. Through the GPR data we were also able to delineate possible structural defects (cracks, small voids) which was not possible with just using the ERT data. Furthermore, a very good matching was evident between the simulated GPR modelling results incorporating field-interpreted features, and the actual field GPR results, thereby validating the proposed data interpretation. The overall survey and modelling approach produces results that are in a very good agreement between them and proved very useful in accessing the wall structure.

  11. Airway wall thickness of allergic asthma caused by weed pollen or house dust mite assessed by computed tomography.

    Science.gov (United States)

    Liu, Liping; Li, Guangrun; Sun, Yuemei; Li, Jian; Tang, Ningbo; Dong, Liang

    2015-03-01

    Little was known about Airway wall thickness of asthma patients with different allergen allergy. So we explored the possible difference of Airway wall thickness of asthma patients mono-sensitized to weed pollen or HDM using high-resolution computed tomography. 85 severe asthma patients were divided into weed pollen group and HDM group according to relevant allergen. 20 healthy donors served as controls. Airway wall area, percentage wall area and luminal area at the trunk of the apical bronchus of the right upper lobe were quantified using HRCT and compared. The values of pulmonary function were assessed as well. There were differences between HDM group and weed pollen group in WA/BSA,WA% and FEF25-75% pred, and no significant difference in FEV1%pred, FEV1/FVC and LA/BSA. In weed pollen group, WA/BSA was observed to correlate with the duration of rhinitis, whereas in HDM group, WA/BSA and LA/BSA was observed to correlate with the duration of asthma. In weed pollen group, FEV1/FVC showed a weak but significant negative correlation with WA%, but in HDM group FEV1/FVC showed a significant positive correlation with WA% and a statistical negative correlation with LA/BSA. FEV1/FVC and FEF25-75% pred were higher and WA/BSA and LA/BSA were lower in healthy control group than asthma group. FEV1%pred and WA% was no significant difference between asthma patients and healthy subjects. There are differences between HDM mono-sensitized subjects and weed pollen mono-sensitized subjects, not only in airway wall thickness, but also small airway obstruction. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Monte Carlo assessment of the finger shallow dose from direct contact with a microcentrifuge tube containing common biotechnology isotopes in solution.

    Science.gov (United States)

    Cutright, Dan; Medich, David; Ring, Joseph

    2012-04-01

    Eppendorf tubes often are used in biomedical research labs and contain radioactive tracers. Although the associated direct contact finger doses are typically small, it is suggested (and in line with the principle of ALARA) to handle these tubes from the cap of the tube. When containing radioactive material, handling a tube near the bottom conical section would unnecessarily increase the skin dose to the fingers. This investigation modeled a 2.0-mL Eppendorf tube containing various individual beta emitting isotopes commonly used in a biomedical research environment (i.e., (14)C, (3)H, (131)I, (32)P, and (35)S) to determine the skin dose when directly handling the tube at the cap end and when handling it at the bottom conical section. The primary goal of this paper is to assess how significantly this dose is altered by handling geometry. The skin dose to a single finger was calculated with Monte Carlo simulations using MCNP5 and determined at a depth of 0.007 cm(2) in water averaged over 10 cm as described in 10CFR20. Results show that the dose rate may vary by as much as a factor of 700 depending on handling geometry.

  13. Bull Moose Tube Company

    Science.gov (United States)

    The EPA is providing notice of a proposed Administrative Penalty Assessment against the Bull Moose Tube Company, a business located at 1819 Clarkson Road, Chesterfield, MO, 63017, for alleged violations at the facility located at 406 East Industrial Drive,

  14. Ultrasonic imaging of tube/support structure of power plant steam generators

    International Nuclear Information System (INIS)

    Saniie, J.; Nagle, D.T.

    1987-01-01

    The corrosion and erosion of steam generator tubing in nuclear power plants can present problems of both safety and economics. In steam generators, the inconel tubes are fit loosely through holes drilled in carbon steel support plates. Corrosion is of particular concern with such tube/support plate structures. Non-protective magnetite can build up on the inner surface of the support plate holes, and allowed to continue unchecked, will fill the gap, eventually denting and fracturing the tube walls. Therefore, periodic nondestructive inspection can be valuable in characterizing corrosion and can be used in evaluating the effectiveness of chemical treatments used to control or reduce corrosion. Presently, they are investigating the feasibility and practicality of using ultrasound in routing testing for gap measurement, for evaluating the corrosion and assessing the degree of denting. The tube/support structure can be modeled as a multilayer, reverberant target, which when tested with ultrasound results in two sets of reverberating echoes [1]. One set corresponds to the tube wall and the other to the support plate. These echoes must be decomposed and identified in order to evaluate the tube/support structure. This report presents experimental results along with a discussion of various measurements and processing techniques for decomposing and interpreting tube/support echoes at different stages of corrosion

  15. Is MSAFP still a useful test for detecting open neural tube defects and ventral wall defects in the era of first-trimester and early second-trimester fetal anatomical ultrasounds?

    Science.gov (United States)

    Roman, Ashley S; Gupta, Simi; Fox, Nathan S; Saltzman, Daniel; Klauser, Chad K; Rebarber, Andrei

    2015-01-01

    To evaluate whether maternal serum α-fetoprotein (MSAFP) improves the detection rate for open neural tube defects (ONTDs) and ventral wall defects (VWD) in patients undergoing first-trimester and early second-trimester fetal anatomical survey. A cohort of women undergoing screening between 2005 and 2012 was identified. All patients were offered an ultrasound at between 11 weeks and 13 weeks and 6 days of gestational age for nuchal translucency/fetal anatomy followed by an early second-trimester ultrasound at between 15 weeks and 17 weeks and 6 days of gestational age for fetal anatomy and MSAFP screening. All cases of ONTD and VWD were identified via query of billing and reporting software. Sensitivity and specificity for detection of ONTD/VWD were calculated, and groups were compared using the Fisher exact test, with p met the criteria for inclusion. Overall, 15 cases of ONTD and 17 cases of VWD were identified; 100% of cases were diagnosed by ultrasound prior to 18 weeks' gestation; none were diagnosed via MSAFP screening (p < 0.001). First-trimester and early second-trimester ultrasound had 100% sensitivity and 100% specificity for diagnosing ONTD/VWD. Ultrasound for fetal anatomy during the first and early second trimester detected 100% of ONTD/VWD in our population. MSAFP is not useful as a screening tool for ONTD and VWD in the setting of this ultrasound screening protocol. © 2014 S. Karger AG, Basel.

  16. SEISMIC RESISTING PERFORMANCE OF A NEW DOUBLE TUBE HYBRID SYSTEM FOR MULTI-STORY BUILDINGS

    OpenAIRE

    Nasruddin

    2012-01-01

    Investigation on Double Tube Hybrid System (DTHS) through experimental work and analytical study are conducted as a part of the proposal on the seismic design method for Double Tubes Hybrid System (DTHS) for buildings. This structural system comprises Energy Dissipation Structural Walls (EDSW) as the interior tube and Spandrel Wall Frame (SWF) as the exterior tube. EDSW is composed of two reinforced concrete walls linked by steel coupling girders. The RC walls are not anchored to the foundati...

  17. Assessment of the Manufacturing Possibility of Thin-Walled Robotic Portals for Conveyor Worklace

    Directory of Open Access Journals (Sweden)

    Peter Michalik

    2018-03-01

    Full Text Available The paper discusses evaluation of machining solutions for oversized thin-walled robotic portal component for conveyance workplaces. The following portal CNC machining centers have been selected. Firstly, a FSGC 300 “portal type” portal was proposed, with a 50000 mm “X” axis and Heidenhain control system, the second portal was a DMU 340 portal with the maximum axis “X” of 6000 mm and Siemens Sinumerik control system and the last portal was the VF-10 / 40 one, with the maximum axis “X” of 3048 mm and Fanuc control system. Further, the method of fixing a thin-walled robotic portal is designed and individual options are evaluated for their economy. The CAM software application used for programming the production was SolidWorks.

  18. Wall Street's assessment of plastic surgery--related technology: a clinical and financial analysis.

    Science.gov (United States)

    Krieger, L M; Shaw, W W

    2000-02-01

    Many plastic surgeons develop technologies that are manufactured by Wall Street-financed companies. Others participate in the stock market as investors. This study examines the bioengineered skin industry to determine whether it integrates clinical and financial information as Wall Street tenets would predict, and to see whether the financial performance of these companies provides any lessons for practicing plastic surgeons. In efficient markets, the assumptions on which independent financial analysts base their company sales and earnings projections are clinically reasonable, the volatility of a company's stock price does not irrationally differ from that of its industry sector, and the buy/sell recommendations of analysts are roughly congruent. For the companies in this study, these key financial parameters were compared with a benchmark index of 69 biotech companies of similar age and annual revenues (Student's t test). Five bioengineered skin companies were included in the study. Analysts estimated that each company would sell its product to between 24 and 45 percent of its target clinical population. The average stock price volatility was significantly higher for study companies than for those in the benchmark index (p companies were significantly less congruent than those for the benchmark companies (p invest in the stock market, because of their unique clinical experience, may sometimes be in the position to evaluate new technologies and companies better than Wall Street experts. Well-timed trades that use this expertise can result in opportunities for profit.

  19. Tuning into YouTube in the Classroom: Improving Assessment Scores through Social Media

    Science.gov (United States)

    Younger, Dylinda W.; Duncan, Jan E.; Hart, LaToya M.

    2013-01-01

    Despite the consistent tendencies of higher-education faculty to utilize single testing measures (i.e. essay or multiple choice), education research indicates effective assessment of student learning must incorporate multiple formats. With the surge of online courses, programs, and universities in the last 20 years, there is an increasing need to…

  20. Infertility in Women: Hysterosalpingographic Assessment of the Fallopian Tubes in Lagos, Nigeria

    Science.gov (United States)

    Akinola, R. A.; Akinola, O. I.; Fabamwo, A. O.

    2009-01-01

    Tubal disease constitutes a major factor in infertility especially in developing countries. This study was undertaken to assess the hysterosalpingographic patterns seen in infertile patients in an urban centre in Lagos. Two hundred and twenty patients who reported from the gynaecology clinic to the radiology department of Lagos State University…

  1. Virtual gap dielectric wall accelerator

    Science.gov (United States)

    Caporaso, George James; Chen, Yu-Jiuan; Nelson, Scott; Sullivan, Jim; Hawkins, Steven A

    2013-11-05

    A virtual, moving accelerating gap is formed along an insulating tube in a dielectric wall accelerator (DWA) by locally controlling the conductivity of the tube. Localized voltage concentration is thus achieved by sequential activation of a variable resistive tube or stalk down the axis of an inductive voltage adder, producing a "virtual" traveling wave along the tube. The tube conductivity can be controlled at a desired location, which can be moved at a desired rate, by light illumination, or by photoconductive switches, or by other means. As a result, an impressed voltage along the tube appears predominantly over a local region, the virtual gap. By making the length of the tube large in comparison to the virtual gap length, the effective gain of the accelerator can be made very large.

  2. Steam generator tube failures

    International Nuclear Information System (INIS)

    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

  3. Tube to limit a bundle of penetrating rays

    International Nuclear Information System (INIS)

    Arauner, A.

    1980-01-01

    The tube of the X-ray therapy equipment, which is adjustable in width, guarantees the same dose rate in the edge zone for all tube widths which can be set. The tube for this purpose consists of wall segments, which can be individually moved via shafts at right angles to their own axis and the axis of symmetry of the tube. The inclination of the wall elements to the axis of symmetry is adjustable by levers running in a curve. (RW) [de

  4. Engineering assessment of inactive uranium mill tailings, Tube City site, Tuba City, Arizona

    International Nuclear Information System (INIS)

    1981-09-01

    Ford, Bacon and Davis Utah Inc. has reevaluated the Tuba City site in order to revise the March 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Tuba City, Arizona. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 0.8 million tons of tailings at the Tuba City site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors. The four alternative actions presented in this engineering assessment range from millsite decontamination with the addition of 3 m of stabilization cover material (Option I), to rterial (Option I), to rema densitometers for measuring cross-sectionally averaged mass velocity in steady steam-water flow are presented. The results are interpreted ntation

  5. Application of dynamic probabilistic safety assessment approach for accident sequence precursor analysis: Case study for steam generator tube rupture

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Han Sul; Heo, Gyun Young [Kyung Hee University, Yongin (Korea, Republic of); Kim, Tae Wan [Incheon National University, Incheon (Korea, Republic of)

    2017-03-15

    The purpose of this research is to introduce the technical standard of accident sequence precursor (ASP) analysis, and to propose a case study using the dynamic-probabilistic safety assessment (D-PSA) approach. The D-PSA approach can aid in the determination of high-risk/low-frequency accident scenarios from all potential scenarios. It can also be used to investigate the dynamic interaction between the physical state and the actions of the operator in an accident situation for risk quantification. This approach lends significant potential for safety analysis. Furthermore, the D-PSA approach provides a more realistic risk assessment by minimizing assumptions used in the conventional PSA model so-called the static-PSA model, which are relatively static in comparison. We performed risk quantification of a steam generator tube rupture (SGTR) accident using the dynamic event tree (DET) methodology, which is the most widely used methodology in D-PSA. The risk quantification results of D-PSA and S-PSA are compared and evaluated. Suggestions and recommendations for using D-PSA are described in order to provide a technical perspective.

  6. Assessment of heavy metals in the industrial effluents, tube-wells and municipal supplied water of Dehradun, India.

    Science.gov (United States)

    Kulshrestha, Shail; Awasthi, Alok; Dabral, S K

    2013-07-01

    The bio-geochemical cycles of metals involve the lands, rivers, oceans and the atmosphere. Although a large number of metals are introduced to the water bodies during their mining and extraction processes and geochemical weathering of rocks, but the role of domestic and industrial wastes is predominant and of much concern. Increased industrial activities has increased the incidence of percolation of toxic metal ions to the soil and water bodies and presently their presence in ecosystem, have reached to an alarming level that environmentalists are finding it difficult to enforce control measures. Human activities and large number of small and big industrial units are increasingly discharging deleterious metals present in the effluents and wastes, to the environment and aquatic systems and have contaminated heavily even the ground water. The toxic metals have a great tendency of bioaccumulation through which they enter the food chain system and ultimately affect adversely the life on this planet Earth in various ways. Further, due to contamination of irrigation system by the harmful Chemicals and toxic metals, the farm products, vegetables, fruits, potable water and even milk is not spared. This paper describes the assessment of the heavy metal concentration in various industrial effluents of the surrounding area. Various physico-chemical characteristics of the effluents collected from various sites are also reported. To assess the status of ground water quality, water samples from four tube wells of different localities of the area and four drinking water samples supplied by Municipal Distribution System were also analyzed.

  7. Application of dynamic probabilistic safety assessment approach for accident sequence precursor analysis: Case study for steam generator tube rupture

    International Nuclear Information System (INIS)

    Lee, Han Sul; Heo, Gyun Young; Kim, Tae Wan

    2017-01-01

    The purpose of this research is to introduce the technical standard of accident sequence precursor (ASP) analysis, and to propose a case study using the dynamic-probabilistic safety assessment (D-PSA) approach. The D-PSA approach can aid in the determination of high-risk/low-frequency accident scenarios from all potential scenarios. It can also be used to investigate the dynamic interaction between the physical state and the actions of the operator in an accident situation for risk quantification. This approach lends significant potential for safety analysis. Furthermore, the D-PSA approach provides a more realistic risk assessment by minimizing assumptions used in the conventional PSA model so-called the static-PSA model, which are relatively static in comparison. We performed risk quantification of a steam generator tube rupture (SGTR) accident using the dynamic event tree (DET) methodology, which is the most widely used methodology in D-PSA. The risk quantification results of D-PSA and S-PSA are compared and evaluated. Suggestions and recommendations for using D-PSA are described in order to provide a technical perspective

  8. Developing effective campaign messages to prevent neural tube defects: a qualitative assessment of women's reactions to advertising concepts.

    Science.gov (United States)

    Massi Lindsey, Lisa L; Silk, Kami J; Von Friederichs-Fitzwater, Marlene M; Hamner, Heather C; Prue, Christine E; Boster, Franklin J

    2009-03-01

    The incidence of neural tube defects (NTDs), serious birth defects of the brain and spine that affect approximately 3,000 pregnancies in the United States each year, can be reduced by 50-70% with daily periconceptional consumption of the B vitamin folic acid. Two studies were designed to assess college women's reactions to and perceptions of potential campaign advertising concepts derived from preproduction formative research to increase folic acid consumption through the use of a daily multivitamin. Study one assessed draft advertising concepts in eight focus groups (N = 71) composed of college-enrolled women in four cities geographically dispersed across the United States. Based on study one results, the concepts were revised and reassessed in study two with a different sample (eight focus groups; N = 73) of college women in the same four cities. Results indicated that participants generally responded favorably to concepts in each of the two studies, and provided insight into individual concepts to increase their overall appeal and effectiveness. The specific findings and implications of these results are discussed.

  9. A review on the conservatism embodied in the integrity assessment procedure of CANDU pressure tubes

    International Nuclear Information System (INIS)

    Chung, Han Sub; Kim, Hong Duk

    2009-01-01

    Excessive conservatism may be embodied in the integrity assessment procedure for PTs of CANDUs, as guided in the CSA N285.8-05 code. Four sources of conservatism are suggested as (1) the effect of thermal history on DHC, (2) the effect of manufacturing variables on properties of PTs, (3) poor definition or limited availability of databases regarding the aging degradation trends and probability density functions of important material properties, and (4) the simplified equations defining threshold condition for the initiation of DHC at the volumetric flaws. It is suggested that both extensive review of databases available and extensive calculation case studies are required to remove the potential excessive conservatism.

  10. Assessment on Event Classification of One Steam Generator Tube Rupture in EU-APR

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Hwan; Kim, Yong Soo [KHNP CRI, Daejeon (Korea, Republic of)

    2016-10-15

    The Fukushima Daiichi nuclear power plant accident showed the vulnerability of coping strategy to beyond design natural disaster such as beyond design earthquake and tsunami. In Korea, the government and industry performed comprehensive safety inspection on all domestic nuclear power plants against beyond design basis external events and fifty action items have been issued. In addition to post- Fukushima action items, the stress tests for all domestic nuclear power plants are on the way to enhance the safety of domestic nuclear power plants through finding the vulnerabilities in intentional stress conditions initiated by beyond design natural disaster. Recently, the stress tests for WOLSONG Unit 1 and KORI Unit 1 have been performed and their assessment results have been reviewed by Korean regulatory body. The assessment of the coping capability of KORI Unit 1 has been performed under simultaneous the extended loss of AC power and loss of ultimate heat sink initiated by beyond design natural disaster. It is concluded that KORI Unit 1 has the capability, in the event of loss of safety functions by beyond design natural disaster, to sufficiently cool down the reactor core without fuel damage, to keep pressure boundaries of the reactor coolant system in transient condition and to control containment and temperature to maintain the integrity of the containment buildings. The several additional items for safety improvement has been drawn to enhance the coping capability for loss of safety functions under beyond design natural disaster in addition to post Fukushima action items.

  11. Assessment on Event Classification of One Steam Generator Tube Rupture in EU-APR

    International Nuclear Information System (INIS)

    Kim, Ji Hwan; Kim, Yong Soo

    2016-01-01

    The Fukushima Daiichi nuclear power plant accident showed the vulnerability of coping strategy to beyond design natural disaster such as beyond design earthquake and tsunami. In Korea, the government and industry performed comprehensive safety inspection on all domestic nuclear power plants against beyond design basis external events and fifty action items have been issued. In addition to post- Fukushima action items, the stress tests for all domestic nuclear power plants are on the way to enhance the safety of domestic nuclear power plants through finding the vulnerabilities in intentional stress conditions initiated by beyond design natural disaster. Recently, the stress tests for WOLSONG Unit 1 and KORI Unit 1 have been performed and their assessment results have been reviewed by Korean regulatory body. The assessment of the coping capability of KORI Unit 1 has been performed under simultaneous the extended loss of AC power and loss of ultimate heat sink initiated by beyond design natural disaster. It is concluded that KORI Unit 1 has the capability, in the event of loss of safety functions by beyond design natural disaster, to sufficiently cool down the reactor core without fuel damage, to keep pressure boundaries of the reactor coolant system in transient condition and to control containment and temperature to maintain the integrity of the containment buildings. The several additional items for safety improvement has been drawn to enhance the coping capability for loss of safety functions under beyond design natural disaster in addition to post Fukushima action items

  12. Assessing mechanical deconstruction of softwood cell wall for cellulosic biofuels production

    Science.gov (United States)

    Jiang, Jinxue

    Mechanical deconstruction offers a promising strategy to overcome biomass recalcitrance for facilitating enzymatic hydrolysis of pretreated substrates with zero chemicals input and presence of inhibitors. The goal of this dissertation research is to gain a more fundamental understanding on the impact of mechanical pretreatment on generating digestible micronized-wood and how the physicochemical characteristics influence the subsequent enzymatic hydrolysis of micronized wood. The initial moisture content of feedstock was found to be the key factor affecting the development of physical features and enzymatic hydrolysis of micronized wood. Lower moisture content resulted in much rounder particles with lower crystallinity, while higher moisture content resulted in the milled particles with larger aspect ratio and crystallinity. The enzymatic hydrolysis of micronized wood was improved as collectively increasing surface area (i.e., reducing particle size and aspect ratio) and decreasing crystallinity during mechanical milling pretreatment. Energy efficiency analysis demonstrated that low-moisture content feedstock with multi-step milling process would contribute to cost-effectiveness of mechanical pretreatment for achieving more than 70% of total sugars conversion. In the early stage of mechanical pretreatment, the types of cell fractures were distinguished by the initial moisture contents of wood, leading to interwall fracture at the middle lamella region for low moisture content samples and intrawall fracture at the inner cell wall for high moisture content samples. The changes in cell wall fractures also resulted in difference in the distribution of surface chemical composition and energy required for milling process. In an effort to exploit the underlying mechanism associated with the reduced recalcitrance in micronized wood, we reported the increased enzymatic sugar yield and correspondingly structural and accessible properties of micronized feedstock. Electronic

  13. Refinements to calandria tube - liquid injection nozzle (CT-LIN) contact assessments

    International Nuclear Information System (INIS)

    Sedran, P.J.

    2012-01-01

    In recent years, the issue of CT-LIN contact, which first gained attention in 1989, has been addressed through CT-LIN gap measurements, followed by analytical predictions of time-to-contact. CT-LIN time-to-contact predictions have been preformed independently by CPUS Limited for Point Lepreau and Gentilly-2 and by AECL Sheridan Park (now Candu Energy Inc.) for Bruce Power and Gentilly-2. Both companies used the CDEPTH code in combination with CT-LIN gap measurements. Subsequent to the assessments for Point Lepreau and Gentilly-2, a recommended approach for future assessments was presented at the 2008 CANDU maintenance conference. Since that time, a number of refinements to the overall strategy for predicting CT-LIN time-to-contact have been developed and are outlined in this paper. The refinements include: 1. The use of ultrasonic LIN elevation measurements to confirm LIN creep sag behaviour 2. The development of a non-linear empirical CT Creep Sag Model 3. The development of a rationale for discrepancies observed in repeated optical CT-LIN gap measurements and a discussion of alternative CT-LIN gap measurements With these refinements, more accurate CT-LIN time-to-contact predictions can be obtained. For stations that plan to refurbish by 210,000 EFPH, the improvement in time-to-contact predictions resulting from the fore mentioned refinements will not be of any real benefit.. However, for stations that are planning life extensions in order to operate beyond 210,000 EFPH, CT-LIN contact will be an issue. For these stations, improvements in CT-LIN contact time predictions would be beneficial. This paper presents a summary of the proposed refinements and demonstrates how they would impact CT-LIN time-to-contact predictions. (author)

  14. Reliability assessment and probability based design of reinforced concrete containments and shear walls

    International Nuclear Information System (INIS)

    Hwang, H.; Reich, M.; Ellingwood, B.; Shinozuka, M.

    1986-03-01

    This report summarizes work completed under the program entitled, ''Probability-Based Load Combinations for Design of Category I Structures.'' Under this program, the probabilistic models for various static and dynamic loads were formulated. The randomness and uncertainties in material strengths and structural resistance were established. Several limit states of concrete containments and shear walls were identified and analytically formulated. Furthermore, the reliability analysis methods for estimating limit state probabilities were established. These reliability analysis methods can be used to evaluate the safety levels of nuclear structures under various combinations of static and dynamic loads. They can also be used to generate analytically the fragility data for PRA studies. In addition to the development of reliability analysis methods, probability-based design criteria for concrete containments and shear wall structures have also been developed. The proposed design criteria are in the load and resistance factor design (LRFD) format. The load and resistance factors are determined for several limit states and target limit state probabilities. Thus, the proposed design criteria are risk-consistent and have a well-established rationale. 73 refs., 18 figs., 16 tabs

  15. Formative assessment to develop oral communication competency using YouTube: self- and peer assessment in engineering

    Science.gov (United States)

    Nikolic, Sasha; Stirling, David; Ros, Montserrat

    2018-07-01

    Obtaining oral communication competency is an important skill for engineering students to prepare them for interacting and working in any professional setting. For engineers, it is also important to be able to present technical information to non-technical audiences. To ensure oral competency, a non-graded formative assessment approach using video with self- and peer assessment was introduced into a final-year engineering thesis course. A low workload approach was used due to growing student numbers and higher pressures on academic staff. A quasi-experimental design was used to investigate the differences between traditional delivery, self-assessment and combined self-assessment with peer feedback. The study found that the formative models were seen by students to help develop their presentation skills. However, the results showed no significant improvement compared to the traditional method. This could be due to previous presentation practice within the degree or more probable, the lack of incentive for weaker students to engage and improve due to the ungraded nature of the activity.

  16. Steam generator tubing development for commercial fast breeder reactors

    International Nuclear Information System (INIS)

    Sessions, C.E.; Uber, C.F.

    1981-01-01

    The development work to design, manufacture, and evaluate pre-stressed double-wall 2/one quarter/ Cr-1 Mo steel tubing for commercial fast breeder reactor steam generator application is discussed. The Westinghouse plan for qualifying tubing vendors to produce this tubing is described. The results achieved to date show that a long length pre-stressed double-wall tube is both feasible and commercially available. The evaluation included structural analysis and experimental measurement of the pre-stress within tubes, as well as dimensional, metallurgical, and interface wear tests of tube samples produced. This work is summarized and found to meet the steam generator design requirements. 10 refs

  17. Assessment of wall friction model in multi-dimensional component of MARS with air–water cross flow experiment

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jin-Hwa [Nuclear Thermal-Hydraulic Engineering Laboratory, Seoul National University, Gwanak 599, Gwanak-ro, Gwanak-gu, Seoul 151-742 (Korea, Republic of); Korea Atomic Energy Research Institute, 989-111, Daedeok-daero, Yuseong-gu, Daejeon 305-600 (Korea, Republic of); Choi, Chi-Jin [Nuclear Thermal-Hydraulic Engineering Laboratory, Seoul National University, Gwanak 599, Gwanak-ro, Gwanak-gu, Seoul 151-742 (Korea, Republic of); Cho, Hyoung-Kyu, E-mail: chohk@snu.ac.kr [Nuclear Thermal-Hydraulic Engineering Laboratory, Seoul National University, Gwanak 599, Gwanak-ro, Gwanak-gu, Seoul 151-742 (Korea, Republic of); Euh, Dong-Jin [Korea Atomic Energy Research Institute, 989-111, Daedeok-daero, Yuseong-gu, Daejeon 305-600 (Korea, Republic of); Park, Goon-Cherl [Nuclear Thermal-Hydraulic Engineering Laboratory, Seoul National University, Gwanak 599, Gwanak-ro, Gwanak-gu, Seoul 151-742 (Korea, Republic of)

    2017-02-15

    Recently, high precision and high accuracy analysis on multi-dimensional thermal hydraulic phenomena in a nuclear power plant has been considered as state-of-the-art issues. System analysis code, MARS, also adopted a multi-dimensional module to simulate them more accurately. Even though it was applied to represent the multi-dimensional phenomena, but implemented models and correlations in that are one-dimensional empirical ones based on one-dimensional pipe experimental results. Prior to the application of the multi-dimensional simulation tools, however, the constitutive models for a two-phase flow need to be carefully validated, such as the wall friction model. Especially, in a Direct Vessel Injection (DVI) system, the injected emergency core coolant (ECC) on the upper part of the downcomer interacts with the lateral steam flow during the reflood phase in the Large-Break Loss-Of-Coolant-Accident (LBLOCA). The interaction between the falling film and lateral steam flow induces a multi-dimensional two-phase flow. The prediction of ECC flow behavior plays a key role in determining the amount of coolant that can be used as core cooling. Therefore, the wall friction model which is implemented to simulate the multi-dimensional phenomena should be assessed by multidimensional experimental results. In this paper, the air–water cross film flow experiments simulating the multi-dimensional phenomenon in upper part of downcomer as a conceptual problem will be introduced. The two-dimensional local liquid film velocity and thickness data were used as benchmark data for code assessment. And then the previous wall friction model of the MARS-MultiD in the annular flow regime was modified. As a result, the modified MARS-MultiD produced improved calculation result than previous one.

  18. Evolution of posterior fossa and brain morphology after in utero repair of open neural tube defects assessed by MRI

    Energy Technology Data Exchange (ETDEWEB)

    Rethmann, Christin; Scheer, Ianina; Kellenberger, Christian Johannes [University Children' s Hospital Zurich, Department of Diagnostic Imaging, Zurich (Switzerland); University of Zurich, The Zurich Center for Fetal Diagnosis and Therapy, Zurich (Switzerland); Children' s Research Center (CRC), Zurich (Switzerland); Meuli, Martin; Mazzone, Luca; Moehrlen, Ueli [University of Zurich, The Zurich Center for Fetal Diagnosis and Therapy, Zurich (Switzerland); Children' s Research Center (CRC), Zurich (Switzerland); University Children' s Hospital Zurich, Department of Pediatric Surgery, Zurich (Switzerland)

    2017-11-15

    To describe characteristics of foetuses undergoing in utero repair of open neural tube defects (ONTD) and assess postoperative evolution of posterior fossa and brain morphology. Analysis of pre- and postoperative foetal as well as neonatal MRI of 27 foetuses who underwent in utero repair of ONTD. Type and level of ONTD, hindbrain configuration, posterior fossa and liquor space dimensions, and detection of associated findings were compared between MRI studies and to age-matched controls. Level of bony spinal defect was defined with exactness of ± one vertebral body. Of surgically confirmed 18 myelomeningoceles (MMC) and 9 myeloschisis (MS), 3 MMC were misdiagnosed as MS due to non-visualisation of a flat membrane on MRI. Hindbrain herniation was more severe in MS than MMC (p < 0.001). After repair, hindbrain herniation resolved in 25/27 cases at 4 weeks and liquor spaces increased. While posterior fossa remained small (p < 0.001), its configuration normalised. Lateral ventricle diameter indexed to cerebral width decreased in 48% and increased in 12% of cases, implying a low rate of progressive obstructive hydrocephalus. Neonatally evident subependymal heterotopias were detected in 33% at preoperative and 50% at postoperative foetal MRI. MRI demonstrates change of Chiari malformation type II (CM-II) features. (orig.)

  19. Evolution of posterior fossa and brain morphology after in utero repair of open neural tube defects assessed by MRI

    International Nuclear Information System (INIS)

    Rethmann, Christin; Scheer, Ianina; Kellenberger, Christian Johannes; Meuli, Martin; Mazzone, Luca; Moehrlen, Ueli

    2017-01-01

    To describe characteristics of foetuses undergoing in utero repair of open neural tube defects (ONTD) and assess postoperative evolution of posterior fossa and brain morphology. Analysis of pre- and postoperative foetal as well as neonatal MRI of 27 foetuses who underwent in utero repair of ONTD. Type and level of ONTD, hindbrain configuration, posterior fossa and liquor space dimensions, and detection of associated findings were compared between MRI studies and to age-matched controls. Level of bony spinal defect was defined with exactness of ± one vertebral body. Of surgically confirmed 18 myelomeningoceles (MMC) and 9 myeloschisis (MS), 3 MMC were misdiagnosed as MS due to non-visualisation of a flat membrane on MRI. Hindbrain herniation was more severe in MS than MMC (p < 0.001). After repair, hindbrain herniation resolved in 25/27 cases at 4 weeks and liquor spaces increased. While posterior fossa remained small (p < 0.001), its configuration normalised. Lateral ventricle diameter indexed to cerebral width decreased in 48% and increased in 12% of cases, implying a low rate of progressive obstructive hydrocephalus. Neonatally evident subependymal heterotopias were detected in 33% at preoperative and 50% at postoperative foetal MRI. MRI demonstrates change of Chiari malformation type II (CM-II) features. (orig.)

  20. Assessment of fluctuating pressure gradient using acceleration spectra in near wall flows

    Science.gov (United States)

    Cadel, Daniel; Lowe, K. Todd

    2015-11-01

    Separation of contributions to the fluctuating acceleration from pressure gradient fluctuations and viscous shear fluctuations in the frequency domain is examined in a turbulent boundary layer. Past work leveraging turbulent accelerations for pressure gradient measurements has neglected the viscous shear term from the momentum equation--an invalid assumption in the case of near wall flows. The present study seeks to account for the influence of the viscous shear term and spectrally reject its contribution, which is thought to be concentrated at higher frequencies. Spectra of velocity and acceleration fluctuations in a flat plate, zero pressure gradient turbulent boundary layer at a momentum thickness Reynolds number of 7500 are measured using a spatially resolving three-component laser Doppler velocimeter. This canonical case data is applied for validation of the spectral approach for future application in more complex aerodynamic flows.

  1. Randomized clinical trial of pigtail catheter versus chest tube in injured patients with uncomplicated traumatic pneumothorax.

    Science.gov (United States)

    Kulvatunyou, N; Erickson, L; Vijayasekaran, A; Gries, L; Joseph, B; Friese, R F; O'Keeffe, T; Tang, A L; Wynne, J L; Rhee, P

    2014-01-01

    Small pigtail catheters appear to work as well as the traditional large-bore chest tubes in patients with traumatic pneumothorax, but it is not known whether the smaller pigtail catheters are associated with less tube-site pain. This study was conducted to compare tube-site pain following pigtail catheter or chest tube insertion in patients with uncomplicated traumatic pneumothorax. This prospective randomized trial compared 14-Fr pigtail catheters and 28-Fr chest tubes in patients with traumatic pneumothorax presenting to a level I trauma centre from July 2010 to February 2012. Patients who required emergency tube placement, those who refused and those who could not respond to pain assessment were excluded. Primary outcomes were tube-site pain, as assessed by a numerical rating scale, and total pain medication use. Secondary outcomes included the success rate of pneumothorax resolution and insertion-related complications. Forty patients were enrolled. Baseline characteristics of 20 patients in the pigtail catheter group were similar to those of 20 patients in the chest tube group. No patient had a flail chest or haemothorax. Pain scores related to chest wall trauma were similar in the two groups. Patients with a pigtail catheter had significantly lower mean(s.d.) tube-site pain scores than those with a chest tube, at baseline after tube insertion (3.2(0.6) versus 7.7(0.6); P pneumothorax, use of a 14-Fr pigtail catheter is associated with reduced pain at the site of insertion, with no other clinically important differences noted compared with chest tubes. NCT01537289 (http://clinicaltrials.gov). © 2013 BJS Society Ltd. Published by John Wiley & Sons Ltd.

  2. Boiling and condensation in microfin tubes

    Science.gov (United States)

    Schlager, Lynn M.

    A general overview of microfin tubes and their applications is presented. Manufacturing processes, commercial availability, experimental heat transfer, and pressure drop data for various refrigerants (including alternative refrigerants and refrigerant-oil mixtures), physical mechanisms of enhancement, and the incorporation of microfin tubes in common heat exchanger configurations are discussed. Microfin tubes, also known by various trade names, are characterized by numerous small fins which typically spiral down the inside wall of tubes at angles ranging from 10 to 30 degrees. The number of fins ranges from 48 to 70 with typical fin heights of 0.12 to 0.30 mm (fin height generally less than 3 percent of the inside diameter of the tube). Fin shapes may vary and the inside surface area of microfin tubes is 10 to 70 percent greater than the area of equivalent smooth tubes. Heat transfer can be enhanced by up to a factor of three with microfin tubes.

  3. Liquid loading experiments with tube wall modifications

    NARCIS (Netherlands)

    Belfroid, S.P.C.; Schiferli, W.; Veltin, J.; Veeken, K.

    2011-01-01

    This paper discusses the multiphase flow mechanism responsible for gas-well liquid loading. It demonstrates that the conventional idea of droplet flow reversal (Turner et al. (1)) does not capture reality and that actual observations are better described by film flow reversal phenomenon. The

  4. Residual stresses estimation in tubes after rapid heating of surface

    International Nuclear Information System (INIS)

    Serikov, S.V.

    1992-01-01

    Results are presented on estimation of residual stresses in tubes of steel types ShKh15, EhP836 and 12KIMF after heating by burning pyrotechnic substance inside tubes. External tube surface was heated up to 400-450 deg C under such treatment. Axial stresses distribution over tube wall thickness was determined for initial state, after routine heat treatment and after heating with the use of fireworks. Inner surface heating was shown to essentially decrease axial stresses in tubes

  5. Evaluation of nondestructive evaluation size measurement for integrity assessment of axial outside diameter stress corrosion cracking in steam generator tubes

    International Nuclear Information System (INIS)

    Joo, Kyung Mun; Hong, Jun Hee

    2015-01-01

    Recently, the initiation of outside diameter stress corrosion cracking (ODSCC) at the tube support plate region of domestic steam generators (SG) with Alloy 600 HTMA tubes has been increasing. As a result, SGs with Alloy 600 HTMA tubes must be replaced early or are scheduled to be replaced prior to their designed lifetime. ODSCC is one of the biggest threats to the integrity of SG tubes. Therefore, the accurate evaluation of tube integrity to determine ODSCC is needed. Eddy current testing (ECT) is conducted periodically, and its results could be input as parameters for evaluating the integrity of SG tubes. The reliability of an ECT inspection system depends on the performance of the inspection technique and ability of the analyst. The detection probability and ECT sizing error of degradation are considered to be the performance indices of a nondestructive evaluation (NDE) system. This paper introduces an optimized evaluation method for ECT, as well as the sizing error, including the analyst performance. This study was based on the results of a round robin program in which 10 inspection analysts from 5 different companies participated. The analysis of ECT sizing results was performed using a linear regression model relating the true defect size data to the measured ECT size data.

  6. Evaluation of nondestructive evaluation size measurement for integrity assessment of axial outside diameter stress corrosion cracking in steam generator tubes

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Kyung Mun [Korea Hydro and Nuclear Power Company Ltd., Central Research Institute, Daejeon (Korea, Republic of); Hong, Jun Hee [Dept. of mechanical Engineering, Chungnam National University, Daejeon (Korea, Republic of)

    2015-02-15

    Recently, the initiation of outside diameter stress corrosion cracking (ODSCC) at the tube support plate region of domestic steam generators (SG) with Alloy 600 HTMA tubes has been increasing. As a result, SGs with Alloy 600 HTMA tubes must be replaced early or are scheduled to be replaced prior to their designed lifetime. ODSCC is one of the biggest threats to the integrity of SG tubes. Therefore, the accurate evaluation of tube integrity to determine ODSCC is needed. Eddy current testing (ECT) is conducted periodically, and its results could be input as parameters for evaluating the integrity of SG tubes. The reliability of an ECT inspection system depends on the performance of the inspection technique and ability of the analyst. The detection probability and ECT sizing error of degradation are considered to be the performance indices of a nondestructive evaluation (NDE) system. This paper introduces an optimized evaluation method for ECT, as well as the sizing error, including the analyst performance. This study was based on the results of a round robin program in which 10 inspection analysts from 5 different companies participated. The analysis of ECT sizing results was performed using a linear regression model relating the true defect size data to the measured ECT size data.

  7. Feeding Tubes

    Science.gov (United States)

    ... feeding therapies have been exhausted. Please review product brand and method of placement carefully with your physician ... Total Parenteral Nutrition. Resources: Oley Foundation Feeding Tube Awareness Foundation Children’s Medical Nutrition Alliance APFED’s Educational Webinar ...

  8. Radioisotope study of Eustachian tube

    International Nuclear Information System (INIS)

    De Rossi, G.; Campioni, P.; Vaccaro, A.

    1988-01-01

    Radioisotope studies of Eustachian tube are suggested in the preoperative phase of tympanoplasty, in order to assess tubal drainage and secretion. The use of gamma camera fitted to a computer allowed the AA, to calculate some semi-quantitative parameters for an exact assessment of the radioactivity transit from the tympanic cass up to the pharyngeal cavity, throughout the Eustachian tube. (orig.) [de

  9. Assessment of thermo-mechanical behavior in CLAM steel first wall structures

    International Nuclear Information System (INIS)

    Liu Fubin; Yao Man

    2012-01-01

    Highlights: ► China Low Activation Martensitic steel (CLAM) as FW the structural material. ► The thermo-mechanical behavior of the FW was analyzed under the condition of normal ITER operation combined effect of plasma heat flux and neutron heating. ► The temperature dependence of the material physical properties of CLAM is summarized. - Abstract: The temperature and strain distributions of the mockup with distinct structural material (SS316L or China Low Activation Martensitic steel (CLAM)) in two-dimensional model were calculated and analyzed, based on a high heat flux (HHF) test recently reported with heat flux of 3.2 MW/m 2 . The calculated temperature and strain results in the first wall (FW), in which SS316L is as the structural material, showed good agreement with HHF test. By substituting CLAM steel for SS316L the contrast analysis indicates that the thermo-mechanical property for CLAM steel is better than that of SS316 at the same condition. Furthermore, the thermo-mechanical behavior of the FW was analyzed under the condition of normal ITER operation combined effect of plasma heat flux and neutron heating.

  10. Assessment of thermo-mechanical behavior in CLAM steel first wall structures

    Energy Technology Data Exchange (ETDEWEB)

    Liu Fubin, E-mail: liufubin_1216@126.com [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, Liaoning (China); Yao Man, E-mail: yaoman@dlut.edu.cn [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, Liaoning (China)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer China Low Activation Martensitic steel (CLAM) as FW the structural material. Black-Right-Pointing-Pointer The thermo-mechanical behavior of the FW was analyzed under the condition of normal ITER operation combined effect of plasma heat flux and neutron heating. Black-Right-Pointing-Pointer The temperature dependence of the material physical properties of CLAM is summarized. - Abstract: The temperature and strain distributions of the mockup with distinct structural material (SS316L or China Low Activation Martensitic steel (CLAM)) in two-dimensional model were calculated and analyzed, based on a high heat flux (HHF) test recently reported with heat flux of 3.2 MW/m{sup 2}. The calculated temperature and strain results in the first wall (FW), in which SS316L is as the structural material, showed good agreement with HHF test. By substituting CLAM steel for SS316L the contrast analysis indicates that the thermo-mechanical property for CLAM steel is better than that of SS316 at the same condition. Furthermore, the thermo-mechanical behavior of the FW was analyzed under the condition of normal ITER operation combined effect of plasma heat flux and neutron heating.

  11. Walled-off pancreatic necrosis and other current concepts in the radiological assessment of acute pancreatitis

    International Nuclear Information System (INIS)

    Cunha, Elen Freitas de Cerqueira; Rocha, Manoel de Souza; Pereira, Fabio Payao; Blasbalg, Roberto; Baroni, Ronaldo Hueb

    2014-01-01

    Acute pancreatitis is an inflammatory condition caused by intracellular activation and extravasation of inappropriate proteolytic enzymes determining destruction of pancreatic parenchyma and peripancreatic tissues. This is a fairly common clinical condition with two main presentations, namely, endematous pancreatitis - a less severe presentation - and necrotizing pancreatitis - the most severe presentation that affects a significant part of patients. The radiological evaluation, particularly by computed tomography, plays a fundamental role in the definition of the management of severe cases, especially regarding the characterization of local complications with implications in the prognosis and in the definition of the therapeutic approach. New concepts include the subdivision of necrotizing pancreatitis into the following presentations: pancreatic parenchymal necrosis with concomitant peripancreatic tissue necrosis, and necrosis restricted to peripancreatic tissues. Moreover, there was a systematization of the terms acute peripancreatic fluid collection, pseudocyst, post-necrotic pancreatic/peripancreatic fluid collections and walled-off pancreatic necrosis. The knowledge about such terms is extremely relevant to standardize the terminology utilized by specialists involved in the diagnosis and treatment of these patients. (author)

  12. Carcinogenicity of multi-walled carbon nanotubes: challenging issue on hazard assessment.

    Science.gov (United States)

    Fukushima, Shoji; Kasai, Tatsuya; Umeda, Yumi; Ohnishi, Makoto; Sasaki, Toshiaki; Matsumoto, Michiharu

    2018-01-25

    This report reviews the carcinogenicity of multi-walled carbon nanotubes (MWCNTs) in experimental animals, concentrating on MWNT-7, a straight fibrous MWCNT. MWCNTs were administered to mice and rats by intraperitoneal injection, intrascrotal injection, subcutaneous injection, intratracheal instillation and inhalation. Intraperitoneal injection of MWNT-7 induced peritoneal mesothelioma in mice and rats. Intrascrotal injection induced peritoneal mesothelioma in rats. Intratracheal instillation of MWCNT-N (another straight fibrous MWCNT) induced both lung carcinoma and pleural mesothelioma in rats. In the whole body inhalation studies, in mice MWNT-7 promoted methylcholanthrene-initiated lung carcinogenesis. In rats, inhalation of MWNT-7 induced lung carcinoma and lung burdens of MWNT-7 increased with increasing concentration of airborne MWNT-7 and increasing duration of exposure. Straight, fibrous MWCNTs exerted carcinogenicity in experimental animals. Phagocytosis of MWCNT fibers by macrophages was very likely to be a principle factor in MWCNT lung carcinogenesis. Using no-observed-adverse-effect level-based approach, we calculated that the occupational exposure limit (OEL) of MWNT-7 for cancer protection is 0.15 μg/m 3 for a human worker. Further studies on the effects of the shape and size of MWCNT fibers and mode of action on the carcinogenicity are required.

  13. Walled-off pancreatic necrosis and other current concepts in the radiological assessment of acute pancreatitis

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Elen Freitas de Cerqueira [Image Memorial/DASA and Diagnoson Medicina Diagnostica, Salvador, BA (Brazil); Rocha, Manoel de Souza; Pereira, Fabio Payao; Blasbalg, Roberto; Baroni, Ronaldo Hueb [Universidade de Sao Paulo (FM/USPU), Sao Paulo, SP (Brazil). Faculdade de Medicina

    2014-05-15

    Acute pancreatitis is an inflammatory condition caused by intracellular activation and extravasation of inappropriate proteolytic enzymes determining destruction of pancreatic parenchyma and peripancreatic tissues. This is a fairly common clinical condition with two main presentations, namely, endematous pancreatitis - a less severe presentation - and necrotizing pancreatitis - the most severe presentation that affects a significant part of patients. The radiological evaluation, particularly by computed tomography, plays a fundamental role in the definition of the management of severe cases, especially regarding the characterization of local complications with implications in the prognosis and in the definition of the therapeutic approach. New concepts include the subdivision of necrotizing pancreatitis into the following presentations: pancreatic parenchymal necrosis with concomitant peripancreatic tissue necrosis, and necrosis restricted to peripancreatic tissues. Moreover, there was a systematization of the terms acute peripancreatic fluid collection, pseudocyst, post-necrotic pancreatic/peripancreatic fluid collections and walled-off pancreatic necrosis. The knowledge about such terms is extremely relevant to standardize the terminology utilized by specialists involved in the diagnosis and treatment of these patients. (author)

  14. Monte Carlo simulations to assess the effects of tube current modulation on breast dose for multidetector CT

    International Nuclear Information System (INIS)

    Angel, Erin; Yaghmai, Nazanin; Jude, Cecilia Matilda; DeMarco, John J; Cagnon, Christopher H; Goldin, Jonathan G; McNitt-Gray, Michael F; Primak, Andrew N; McCollough, Cynthia H; Stevens, Donna M; Cody, Dianna D

    2009-01-01

    Tube current modulation was designed to reduce radiation dose in CT imaging while maintaining overall image quality. This study aims to develop a method for evaluating the effects of tube current modulation (TCM) on organ dose in CT exams of actual patient anatomy. This method was validated by simulating a TCM and a fixed tube current chest CT exam on 30 voxelized patient models and estimating the radiation dose to each patient's glandular breast tissue. This new method for estimating organ dose was compared with other conventional estimates of dose reduction. Thirty detailed voxelized models of patient anatomy were created based on image data from female patients who had previously undergone clinically indicated CT scans including the chest area. As an indicator of patient size, the perimeter of the patient was measured on the image containing at least one nipple using a semi-automated technique. The breasts were contoured on each image set by a radiologist and glandular tissue was semi-automatically segmented from this region. Previously validated Monte Carlo models of two multidetector CT scanners were used, taking into account details about the source spectra, filtration, collimation and geometry of the scanner. TCM data were obtained from each patient's clinical scan and factored into the model to simulate the effects of TCM. For each patient model, two exams were simulated: a fixed tube current chest CT and a tube current modulated chest CT. X-ray photons were transported through the anatomy of the voxelized patient models, and radiation dose was tallied in the glandular breast tissue. The resulting doses from the tube current modulated simulations were compared to the results obtained from simulations performed using a fixed mA value. The average radiation dose to the glandular breast tissue from a fixed tube current scan across all patient models was 19 mGy. The average reduction in breast dose using the tube current modulated scan was 17%. Results were

  15. Simulating secondary organic aerosol in a regional air quality model using the statistical oxidation model – Part 2: Assessing the influence of vapor wall losses

    OpenAIRE

    Cappa, Christopher D.; Jathar, Shantanu H.; Kleeman, Michael J.; Docherty, Kenneth S.; Jimenez, Jose L.; Seinfeld, John H.; Wexler, Anthony S.

    2016-01-01

    The influence of losses of organic vapors to chamber walls during secondary organic aerosol (SOA) formation experiments has recently been established. Here, the influence of such losses on simulated ambient SOA concentrations and properties is assessed in the UCD/CIT regional air quality model using the statistical oxidation model (SOM) for SOA. The SOM was fit to laboratory chamber data both with and without accounting for vapor wall losses following the approa...

  16. In reactor measurements, modeling and assessments to predict liquid injection shutdown system nozzle to Calandria tube time to contact

    International Nuclear Information System (INIS)

    Kirstein, K.; Kalenchuk, D.

    2011-01-01

    Over the past few years there has been an expanding effort to assess the potential for Calandria Tubes (CTs) coming into contact with Liquid Injection Shutdown System (LISS) Nozzles to ensure continued contact-free operation as required by CSA N285.4. LISS Nozzles (LINs), which run perpendicular to and between rows of fuel channels, sag at a slower rate than the fuel channels. As a result certain LINs may come in contact with CTs above them. The CT/LIN gaps can be predicted from calculated CT sag, LIN sag and a number of component and installation tolerances. This method however results in very conservative predictions when compared to measurements, confirmed with the in reactor measurements initiated in 2000, when gaps were successfully measured the first time using images obtained from a camera-assisted measurement tool inserted into the calandria. To reduce the conservatism of the CT/LIN gap predictions, statistical CT/LIN gap models are used instead. They are derived from a comparison between calculated gaps based on nominal dimensions and the visual image based measured gaps. These reactor specific (typically 95% confidence level) CT/LIN gap models account for all uncertainties and deviations from nominal values. Prediction error margins reduce as more in-reactor gap measurements become available. Each year more measurements are being made using this standardized visual CT/LIN proximity method. The subsequently prepared reactor-specific models have been used to provide time to contact for every channel above the LINs at these stations. In a number of cases it has been used to demonstrate that the reactor can be operated to its end of life before refurbishment with no predicted contact, or specific at-risk channels have been identified for which appropriate remedial actions could be implemented in a planned manner. (author)

  17. MARS-KS Code Assessment for Condensation Heat Transfer in Horizontal Tube with the Presence of Non-Condensable Gas using Purdue Experiment

    International Nuclear Information System (INIS)

    Jeon, Seong Su; Lee, Byung Chul; Park, Ju Yeop; Seul, Kwang Won

    2011-01-01

    In South Korea, advanced power reactor plus (APR+), as a Korean specific reactor, is currently under development for the export strategy. In order to raise competitiveness of the APR+ in the world market, it is necessary to develop the original technology for the improved technology, economics, and safety features. For this purpose, a passive auxiliary feedwater system (PAFS) was adopted as an improved safety design concept of APR+: and then there have been many efforts to develop the PAFS. According to PAFS design concept, PAFS can completely replace the auxiliary feedwater system. When the design basis accident, in which feedwater is unavailable, occurs, the PAFS can remove the residual heat in the core and then prevent the core damage. In the PAFS with the horizontal type heat exchanger, two-phase natural circulation, condensation heat transfer in tube, boiling heat transfer in pool, natural convection in pool, etc. are considered as very important thermalhydraulic phenomena (see Fig. 1). Compared with the vertical heat exchanger from these phenomena, the major difference of the horizontal heat exchanger is the condensation heat transfer phenomena in the tube side. There have been many efforts to understand the condensation heat transfer with in the presence of NC gas in tube but most researches focused on the condensation heat transfer in vertical tube. Therefore the details of the condensation heat transfer in the presence of NC gas in horizontal condenser tubes are not well understood. In order to develop the safety evaluation system for APR+ PAFS, it is required to evaluate the capability and applicability of the MARS-KS code for modeling the condensation heat transfer in the horizontal tube with NC gas because many heat transfer correlations in MARS-KS are known to have much uncertainty. In particular, there is no reliable model for the condensation phenomena in horizontal tube with NC gas. In order to assess the MARS-KS code results and identify the

  18. Aquatic toxicity assessment of single-walled carbon nanotubes using zebrafish embryos

    Energy Technology Data Exchange (ETDEWEB)

    Pan Huichin; Lin Yujun; Li Mengwei [Department of Biomedical Sciences, Chung Shan Medical University, Taichung 40201, Taiwan (China); Chuang Hanni; Chou Chengchung, E-mail: bioccc@ccu.edu.tw, E-mail: hp29@csmu.edu.tw [Department of Life Science, National Chung Cheng University, Min-Hsiung, 62102 Taiwan (China)

    2011-07-06

    Zebrafish embryos selected at the 64-cell stage were exposed to various concentrations of amide functionalized single-walled carbon nanotubes (SWCNTs) ranging from 1 to 10 {mu}g/ml dissolved in 1% Pluronic F-68 (a cell culture grade surfactant), and the development of embryos was examined from 24 to 120 hours post fertilization (hpf). Incubation of embryos in 1% F-68 did not induce overt abnormal phenotype as compared to the wild-type; neither did it cause significant mortality during the exposure period. Generally, there was a slight developmental delay in larvae treated with SWCNTs of 5 {mu}g/ml or above. Only larvae exposed to {>=} 5 {mu}g/ml SWCNTs showed significantly reduced survival rates. About 50% of the embryos exposed to 5 {mu}g/ml showed abnormal phenotypes at 24 hpf as compared to the control group. As development proceeds to 120 hpf, more embryos displayed defective morphology. A slight hatching delay was observed in embryos exposed to concentrations above 5 {mu}g/ml. There was a general reduction of body axes, including narrowed somite and shortened yolk stalk. In addition, pigmentation in the ventral trunk area was less than that observed in control group. The body lengths of the exposed embryos were decreased significantly at 48 hpf (3.11 mm in control vs. 3.00 mm in SWCNTs-exposed embryos). However, exposure to SWCNTs did not affect the number of somites. Other features that were noticed in the SWCNTs-exposed embryos included edema and shrinkage and blebbling of the epidermal lining. Most of these observed phenotypes persisted from 48 hpf through 120 hpf. Overall, the aforementioned results indicate that soluble amide-functionalized SWCNTs are toxic to zebrafish embryos at a minimum concentration of 5 {mu}g/ml.

  19. Influence of Electric Fields and Conductivity on Pollen Tube Growth assessed via Electrical Lab-on-Chip

    Science.gov (United States)

    Agudelo, Carlos; Packirisamy, Muthukumaran; Geitmann, Anja

    2016-01-01

    Pollen tubes are polarly growing plant cells that are able to rapidly respond to a combination of chemical, mechanical, and electrical cues. This behavioural feature allows them to invade the flower pistil and deliver the sperm cells in highly targeted manner to receptive ovules in order to accomplish fertilization. How signals are perceived and processed in the pollen tube is still poorly understood. Evidence for electrical guidance in particular is vague and highly contradictory. To generate reproducible experimental conditions for the investigation of the effect of electric fields on pollen tube growth we developed an Electrical Lab-on-Chip (ELoC). Pollen from the species Camellia displayed differential sensitivity to electric fields depending on whether the entire cell or only its growing tip was exposed. The response to DC fields was dramatically higher than that to AC fields of the same strength. However, AC fields were found to restore and even promote pollen growth. Surprisingly, the pollen tube response correlated with the conductivity of the growth medium under different AC frequencies—consistent with the notion that the effect of the field on pollen tube growth may be mediated via its effect on the motion of ions. PMID:26804186

  20. An investigation on vulnerability assessment of steel structures with thin steel shear wall through development of fragility curves

    Directory of Open Access Journals (Sweden)

    Mohsen Gerami

    2017-02-01

    Full Text Available Fragility curves play an important role in damage assessment of buildings. Probability of damage induction to the structure against seismic events can be investigated upon generation of afore mentioned curves. In current research 360 time history analyses have been carried out on structures of 3, 10 and 20 story height and subsequently fragility curves have been adopted. The curves are developed based on two indices of inter story drifts and equivalent strip axial strains of the shear wall. Time history analysis is carried out in Perform 3d considering 10 far field seismograms and 10 near fields. Analysis of low height structures revealed that they are more vulnerable in accelerations lower than 0.8 g in near field earthquakes because of higher mode effects. Upon the generated fragility curves it was observed that middle and high structures have more acceptable performance and lower damage levels compared to low height structures in both near and far field seismic hazards.

  1. Changing the Diameter of a Viewing Tube

    Science.gov (United States)

    Obara, Samuel

    2009-01-01

    This article is about the students' investigation about the relationship between the diameter of the view tubes (x) of constant lengths and the viewable vertical distance (y) on the wall while keeping the perpendicular distance from the eyeball to the wall constant. The students collected data and used and represented it in tabular and graphical…

  2. Steam generator tube extraction

    International Nuclear Information System (INIS)

    Delorme, H.

    1985-05-01

    To enable tube examination on steam generators in service, Framatome has now developed a process for removing sections of steam generator tubes. Tube sections can be removed without being damaged for treating the tube section expanded in the tube sheet

  3. Geometric theory of flexible and expandable tubes conveying fluid: equations, solutions and shock waves

    OpenAIRE

    Gay-Balmaz, François; Putkaradze, Vakhtang

    2018-01-01

    We present a theory for the three-dimensional evolution of tubes with expandable walls conveying fluid. Our theory can accommodate arbitrary deformations of the tube, arbitrary elasticity of the walls, and both compressible and incompressible flows inside the tube. We also present the theory of propagation of shock waves in such tubes and derive the conservation laws and Rankine-Hugoniot conditions in arbitrary spatial configuration of the tubes, and compute several examples of particular sol...

  4. Tensor tenopexy: a clinical study to assess its effectiveness in improving Eustachian tube function and preventing hearing loss in patients with cleft palate.

    Science.gov (United States)

    Tiwari, Raja; Sharma, Ramesh K; Panda, Naresh K; Munjal, Sanjay; Makkar, Surinder

    2013-09-01

    There is a consensus about the occurrence of otitis media in children with cleft palate before repair. However, controversy continues regarding the recovery of Eustachian tube function and level of hearing loss in the patients after cleft palate repair. Levator sling palatoplasty is an important component of the cleft repair. Most surgeons would routinely transect the tensor tendon (tensor tenotomy) during the course of palatoplasty. However, this procedure may pose a risk to Eustachian tube function. Some authorities feel that addition of tensor tenopexy during palatoplasty would maintain the Eustachian tube in an open conformation, thereby improving middle ear ventilation. The present study assesses the effectiveness of tensor tenopexy in improving Eustachian tube function and preventing hearing loss in cleft palate patients treated with palatoplasty. A prospective randomised controlled trial was conducted in the Department of Plastic Surgery at a tertiary care institute in India. A total of 17 children in the age group of 9-24 months were assigned to one of two groups: palatoplasty with either tensor tenotomy (n = 8) or tensor tenotomy with tensor tenopexy (n = 9). All patients were subjected to tympanometry, otoscopy and brainstem evoked response audiometry before surgery and at 3, 6, 9 and 12 months after surgery. Of these, 52.9% of patients already had hearing loss at the time of presentation. Hearing loss and middle ear effusion persisted even after palatoplasty. There was no significant difference in hearing loss and middle ear effusion between the two groups of patients. Thus, tensor tenopexy was not found to be helpful in maintaining Eustachian tube function or preventing hearing loss in cleft palate patients. However, further long-term studies are needed to confirm this study. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  5. A simple method for accurate endotracheal placement of an intubation tube in Guinea pigs to assess lung injury following chemical exposure.

    Science.gov (United States)

    Nambiar, M P; Gordon, R K; Moran, T S; Richards, S M; Sciuto, A M

    2007-01-01

    ABSTRACT Guinea pigs are considered as the animal model of choice for toxicology and medical countermeasure studies against chemical warfare agents (CWAs) and toxic organophosphate pesticides because of the low levels of carboxylesterase compared to rats and mice. However, it is difficult to intubate guinea pigs without damaging the larynx to perform CWA inhalation experiments. We describe an easy technique of intubation of guinea pigs for accurate endotracheal placement of the intubation tube. The technique involves a speculum made by cutting the medium-size ear speculum in the midline leaving behind the intact circular connector to the otoscope. Guinea pigs were anesthetized with Telazol/meditomidine, the tongue was pulled using blunt forceps, and an otoscope attached with the specially prepared speculum was inserted gently. Insertion of the speculum raises the epiglottis and restrains the movements of vocal cord, which allows smooth insertion of the metal stylet-reinforced intubation tube. Accurate endotracheal placement of the intubation tube was achieved by measuring the length from the tracheal bifurcation to vocal cord and vocal cord to the upper front teeth. The average length of the trachea in guinea pigs (275 +/- 25 g) was 5.5 +/- 0.2 cm and the distance from the vocal cord to the front teeth was typically 3 cm. Coinciding an intubation tube marked at 6 cm with the upper front teeth accurately places the intubation tube 2.5 cm above the tracheal bifurcation. This simple method of intubation does not disturb the natural flora of the mouth and causes minimum laryngeal damage. It is rapid and reliable, and will be very valuable in inhalation exposure to chemical/biological warfare agents or toxic chemicals to assess respiratory toxicity and develop medical countermeasures.

  6. Precision heat forming of tetrafluoroethylene tubing

    Science.gov (United States)

    Ruiz, W. V.; Thatcher, C. S. (Inventor)

    1981-01-01

    An invention that provides a method of altering the size of tetrafluoroethylene tubing which is only available in limited combination of wall thicknesses and diameter are discussed. The method includes the steps of sliding the tetrafluoroethylene tubing onto an aluminum mandrel and clamping the ends of the tubing to the mandrel by means of clamps. The tetrafluorethylene tubing and mandrel are then placed in a supporting coil which with the mandrel and tetrafluorethylene tubing are then positioned in a insulated steel pipe which is normally covered with a fiber glass insulator to smooth out temperature distribution therein. The entire structure is then placed in an event which heats the tetrafluorethylene tubing which is then shrunk by the heat to the outer dimension of the aluminum mandrel. After cooling the aluminum mandrel is removed from the newly sized tetrafluorethylene tubing by a conventional chemical milling process.

  7. Assessment of Reusing 14-Ton, Thin-Wall, Depleted UF6 Cylinders as LLW Disposal Containers

    International Nuclear Information System (INIS)

    O'Connor, D.G.; Poole, A.B.; Shelton, J.H.

    2000-01-01

    Approximately 700,000 MT of DUF 6 is stored, or will be produced under a current agreement with the USEC, at the Paducah site in Kentucky, Portsmouth site in Ohio, and ETTP site in Tennessee. On July 21, 1998, the 105th Congress approved Public Law 105-204, which directed that facilities be built at the Kentucky and Ohio sites to convert DUF 6 to a stable form for disposition. On July 6, 1999, the Department of Energy (DOE) issued the ''Final Plan for the Conversion of Depleted Uranium Hexafluoride as Required by Public Law 105-204'', in which DOE committed to develop a ''Depleted Uranium Hexafluoride Materials Use Roadmap''. On September 1,2000, DOE issued the ''Draft Depleted Uranium Hexafluoride Materials Use Roadmap'' (Roadmap), which provides alternate paths for the long-term storage, beneficial use, and eventual disposition of each product form and material that will result from the DUF 6 conversion activity. One of the paths being considered for DUF 6 cylinders is to reuse the empty cylinders as containers to transport and dispose of LLW, including the converted DU. The Roadmap provides results of the many alternate uses and disposal paths for conversion products and the empty DUF 6 storage cylinders. As a part of the Roadmap, evaluations were conducted of cost savings, technical maturity, barriers to implementation, and other impacts. Results of these evaluations indicate that using the DUF 6 j storage cylinders as LLW disposal containers could provide moderate cost savings due to the avoided cost of purchasing LLW packages and the avoided cost of disposing of the cylinders. No significant technical or institutional .issues were identified that.would make using cylinders as LLW packages less effective than other disposition paths. Over 58,000 cylinders have been used, or will be used, to store DUF 6 . Over 5 1,000 of those cylinders are 14TTW cylinders with a nominal wall thickness of 5/16-m (0.79 cm). These- 14TTW cylinders, which have a nominal diameter

  8. Design and performance of a straw tube drift chamber

    Science.gov (United States)

    Oh, S. H.; Wesson, D. K.; Cooke, J.; Goshaw, A. T.; Robertson, W. J.; Walker, W. D.

    1991-06-01

    The design and performance of the straw drift chambers used in E735 is reported. The chambers are constructed from 2.5 cm radius aluminized mylar straw tubes with wall thickness less than 0.2 mm. Also, presented are the results of tests with 2 mm radius straw tubes. The small tube has a direct detector application at the Superconducting Super Collider.

  9. Identification and Assessment of Paradoxical Ventricular Wall Motion Using ECG Gated Blood Pool Scan - Comparison of cine Loop , Phase Analysis and Paradox Image -

    International Nuclear Information System (INIS)

    Lee, Jae Tae; Kim, Gwang Weon; Lee, Kyu Bo; Chung, Byung Chun; Whang, Kee Suk; Chae, Sung Chul; Paek, Wee Hyun; Cheon, Jae Eun; Lee, Hyong Woo; Chung, Jin Hong

    1990-01-01

    Sixty-four patients with paradoxical ventricular wall motion noticed both in angiocardiography or 2-dimensional echocardiography were assessed by ECG gated blood pool scan (GBPS). Endless cine loop image, phase and amplitude images and paradox image obtained by visual inspection of each cardiac beat or Fourier transformation of acquired raw data were investigated to determine the incremental value of GBPS with these processing methods for identification of paradoxical ventricular wall motion. The results were as follows:1) Paradoxical wall motions were observed on interventricular septum in 34 cases, left ventricular free wall in 26 and right ventricular wall in 24. Underlying heart diseases were is chemic (23 cases) valvular(9), congenital heart disease (12), cardiomyopathy (5), pericardial effusion(5), post cardiac surgery(3), corpulmonale (2), endocarditis (l) and right ventricular tumor(l). 2) Left ventricular ejection fractions of patients with paradoxical left ventricular wall motion were significantly lower than those with paradoxical septal motion (p <0.005). 3) The sensitivity of each processing methods for detecting paradoxical wall motion was 76.9% by phase analysis, 74.6% by endless cine loop mapping and 68.4% by paradox image manipulation respectively. Paradoxial motions visualized only in phase, paradox or both images were appeared as hypokinesia or akinesia in cine loop image. 4) All events could be identified by at least one of above three processing methods, however only 34 cases (48.4%) showed the paradoxical motions in all of the three images. By these findings, we concluded that simultaneous inspection of all above three processing methods-endless cine loop, phase analysis and paradox image is necessary for accurate identification and assessment of paradoxical ventricular wall motion when performing GBPS.

  10. Identification and Assessment of Paradoxical Ventricular Wall Motion Using ECG Gated Blood Pool Scan - Comparison of cine Loop , Phase Analysis and Paradox Image -

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Tae; Kim, Gwang Weon; Lee, Kyu Bo; Chung, Byung Chun; Whang, Kee Suk; Chae, Sung Chul; Paek, Wee Hyun; Cheon, Jae Eun [Kyungpook National University School of Medicine, Daegu (Korea, Republic of); Lee, Hyong Woo; Chung, Jin Hong [Yeongnam National University College of Medicine, Daegu (Korea, Republic of)

    1990-07-15

    Sixty-four patients with paradoxical ventricular wall motion noticed both in angiocardiography or 2-dimensional echocardiography were assessed by ECG gated blood pool scan (GBPS). Endless cine loop image, phase and amplitude images and paradox image obtained by visual inspection of each cardiac beat or Fourier transformation of acquired raw data were investigated to determine the incremental value of GBPS with these processing methods for identification of paradoxical ventricular wall motion. The results were as follows:1) Paradoxical wall motions were observed on interventricular septum in 34 cases, left ventricular free wall in 26 and right ventricular wall in 24. Underlying heart diseases were is chemic (23 cases) valvular(9), congenital heart disease (12), cardiomyopathy (5), pericardial effusion(5), post cardiac surgery(3), corpulmonale (2), endocarditis (l) and right ventricular tumor(l). 2) Left ventricular ejection fractions of patients with paradoxical left ventricular wall motion were significantly lower than those with paradoxical septal motion (p <0.005). 3) The sensitivity of each processing methods for detecting paradoxical wall motion was 76.9% by phase analysis, 74.6% by endless cine loop mapping and 68.4% by paradox image manipulation respectively. Paradoxial motions visualized only in phase, paradox or both images were appeared as hypokinesia or akinesia in cine loop image. 4) All events could be identified by at least one of above three processing methods, however only 34 cases (48.4%) showed the paradoxical motions in all of the three images. By these findings, we concluded that simultaneous inspection of all above three processing methods-endless cine loop, phase analysis and paradox image is necessary for accurate identification and assessment of paradoxical ventricular wall motion when performing GBPS.

  11. Attenuation of concentration fluctuations of water vapor and other trace gases in turbulent tube flow

    Directory of Open Access Journals (Sweden)

    W. J. Massman

    2008-10-01

    Full Text Available Recent studies with closed-path eddy covariance (EC systems have indicated that the attenuation of fluctuations of water vapor concentration is dependent upon ambient relative humidity, presumably due to sorption/desorption of water molecules at the interior surface of the tube. Previous studies of EC-related tube attenuation effects have either not considered this issue at all or have only examined it superficially. Nonetheless, the attenuation of water vapor fluctuations is clearly much greater than might be expected from a passive tracer in turbulent tube flow. This study reexamines the turbulent tube flow issue for both passive and sorbing tracers with the intent of developing a physically-based semi-empirical model that describes the attenuation associated with water vapor fluctuations. Toward this end, we develop a new model of tube flow dynamics (radial profiles of the turbulent diffusivity and tube airstream velocity. We compare our new passive-tracer formulation with previous formulations in a systematic and unified way in order to assess how sensitive the passive-tracer results depend on fundamental modeling assumptions. We extend the passive tracer model to the vapor sorption/desorption case by formulating the model's wall boundary condition in terms of a physically-based semi-empirical model of the sorption/desorption vapor fluxes. Finally we synthesize all modeling and observational results into a single analytical expression that captures the effects of the mean ambient humidity and tube flow (Reynolds number on tube attenuation.

  12. Fracture analysis of axially cracked pressure tube of pressurized heavy water reactor

    International Nuclear Information System (INIS)

    Krishnan, S.; Bhasin, V.; Mahajan, S.C.

    1997-01-01

    Three Dimensional (313) finite element elastic plastic fracture analysis was done for through wall axially cracked thin pressure tubes of 220 MWe Indian Pressurized Heavy Water Reactor. The analysis was done for Zr-2 and Zr-2.5Nb pressure tubes operating at 300 degrees C and subjected to 9.5 Mpa internal pressure. Critical crack length was determined based on tearing instability concept. The analysis included the effect of crack face pressure due to the leaking fluid from tube. This effect was found to be significant for pressure tubes. The available formulae for calculating J (for axially cracked tubes) do not take into account the effect of crack face pressure. 3D finite element analysis also gives insight into variation of J across the thickness of pressure tube. It was observed that J is highest at the mid-surface of tube. The results have been presented in the form of across the thickness average J value and a peak factor on J. Peak factor on J is ratio of J at mid surface to average J value. Crack opening area for different cracked lengths was calculated from finite element results. The fracture assessment of pressure tubes was also done using Central Electricity Generating Board R-6 method. Ductile tearing was considered

  13. Fracture analysis of axially cracked pressure tube of pressurized heavy water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, S.; Bhasin, V.; Mahajan, S.C. [Bhabha Atomic Research Centre, Bombay (India)] [and others

    1997-04-01

    Three Dimensional (313) finite element elastic plastic fracture analysis was done for through wall axially cracked thin pressure tubes of 220 MWe Indian Pressurized Heavy Water Reactor. The analysis was done for Zr-2 and Zr-2.5Nb pressure tubes operating at 300{degrees}C and subjected to 9.5 Mpa internal pressure. Critical crack length was determined based on tearing instability concept. The analysis included the effect of crack face pressure due to the leaking fluid from tube. This effect was found to be significant for pressure tubes. The available formulae for calculating J (for axially cracked tubes) do not take into account the effect of crack face pressure. 3D finite element analysis also gives insight into variation of J across the thickness of pressure tube. It was observed that J is highest at the mid-surface of tube. The results have been presented in the form of across the thickness average J value and a peak factor on J. Peak factor on J is ratio of J at mid surface to average J value. Crack opening area for different cracked lengths was calculated from finite element results. The fracture assessment of pressure tubes was also done using Central Electricity Generating Board R-6 method. Ductile tearing was considered.

  14. Test Station for Measuring Aluminum Tube Geometrical Parameters

    CERN Document Server

    Oansea, D; Gongadze, A L; Gostkin, M I; Dedovich, D V; Evtoukhovitch, P G; Comanescu, B; Kotov, S A; Necsoiu, T; Potrap, I N; Rogalev, E V; Tskhadadze, E G; Chelkov, G A

    2001-01-01

    A test station for quality control of aluminum tube outer diameter and wall thickness is presented. The tested tubes are used for drift detector assembly of ATLAS (LHC, CERN) muon system. The outer diameter and wall thickness of aluminium tubes are measured by means of noncontact optical and ultrasonic methods respectively with the accuracy of 3 {\\mu}m. The testing process is automatic and interacts with the production data base.

  15. Spring/dimple instrument tube restraint

    International Nuclear Information System (INIS)

    DeMario, E.E.; Lawson, C.N.

    1993-01-01

    A nuclear fuel assembly for a pressurized water nuclear reactor has a spring and dimple structure formed in a non-radioactive insert tube placed in the top of a sensor receiving instrumentation tube thimble disposed in the fuel assembly and attached at a top nozzle, a bottom nozzle, and intermediate grids. The instrumentation tube thimble is open at the top, where the sensor or its connection extends through the cooling water for coupling to a sensor signal processor. The spring and dimple insert tube is mounted within the instrumentation tube thimble and extends downwardly adjacent the top. The springs and dimples restrain the sensor and its connections against lateral displacement causing impact with the instrumentation tube thimble due to the strong axial flow of cooling water. The instrumentation tube has a stainless steel outer sleeve and a zirconium alloy inner sleeve below the insert tube adjacent the top. The insert tube is relatively non-radioactivated inconel alloy. The opposed springs and dimples are formed on diametrically opposite inner walls of the insert tube, the springs being formed as spaced axial cuts in the insert tube, with a web of the insert tube between the cuts bowed radially inwardly for forming the spring, and the dimples being formed as radially inward protrusions opposed to the springs. 7 figures

  16. Assessment of maxillary sinus wall thickness with paranasal sinus digital tomosynthesis and CT

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Ji Eun; Shim, Sung Shine; Kim, Yoo Kyung; Kong, Kyoung Ae [Mokdong Hospital, Ewha Womans University School of Medicine, Seoul (Korea, Republic of)

    2017-05-15

    This study was performed to compare paranasal sinus tomosynthesis with computed tomography (CT) imaging as a radiologic tool to evaluate the paranasal sinuses, using measurement of the soft tissue thickness of the maxillary sinus. A total of 114 patients with sinusitis who underwent both paranasal sinus digital tomosynthesis (DT) and CT were enrolled in this retrospective study. Two observers independently assessed soft tissue thickness in both maxillary sinus chambers using both DT and CT images. The mean difference in soft tissue thickness measured by each observer was −0.31 mm on CT and 0.15 mm on DT. The mean differences in soft tissue thickness measured with DT and CT were −0.15 by observer 1 and −0.31 by observer 2. Evaluation of the agreement in measurement of soft tissue thickness in the maxillary sinus using DT and CT showed a high intraclass correlation, with the 95% limit of agreement ranging from −3.36 mm to 3.06 mm [intraclass correlation coefficient (ICC), 0.994: p<0.01] for observer 1 and from −5.56 mm to 4.95 mm (ICC, 0.984: p<0.01) for observer 2. As an imaging tool, DT is comparable to CT for assessing the soft tissue thickness of maxillary sinuses in patients with sinusitis.

  17. Alternative methodology for assessing part-through-wall cracks in carbon steel bends removed from Point Lepreau Generating Station

    Energy Technology Data Exchange (ETDEWEB)

    Duan Xinjian, E-mail: duanx@aecl.c [Senior Engineer, Reactor Engineering Department, Atomic Energy of Canada Ltd., Mississauga, ON (Canada); Kozluk, Michael J., E-mail: kozlukm@aecl.c [Independent Consultant, Oakville, ON (Canada); Gendron, Tracy [Manager-HTS Materials Integrity, Atomic Energy of Canada Ltd., Chalk River, ON (Canada); Slade, John [Senior Technical Advisor, Point Lepreau Generating Station, Lepreau, NB (Canada)

    2011-03-15

    In 2008 April Point Lepreau Generating Station entered an extended refurbishment outage that will involve the replacement of key reactor components (fuel channels and connecting feeder pipes). Prior to the refurbishment outage, New Brunswick Power Nuclear had been successfully managing intergranular, axial cracking of carbon steel feeder piping, that were also experiencing thinning, in the Point Lepreau Generating Station, primarily by an aggressive program of inspection, repair and testing of ex-service material. For the previous three maintenance outages, a probabilistic safety evaluation (PSE) had been used to demonstrate that annual inspection of the highest risk locations maintains the nuclear safety risk from cracking at an acceptably low level. The PSE makes use of the Failure Assessment Diagram (FAD) model to predict the failure of part-through-wall cracks. Burst-pressure testing of two ex-service feeder pipe sections with part-through-wall cracks showed that this FAD model significantly under predicts the failure pressure measured in the component tests. Use of this FAD model introduces undesirable conservatism into PSE assessments that are used to optimize feeder piping inspection and maintenance plans. This paper describes an alternative finite element approach, which could be used to provide more representative structural models for use in PSE assessments. This alternative approach employs the elasto-plastic large strain finite element formulation; uses representative material properties; considers the spatial microstructural distribution; accounts for the effect of work hardening rate; models all deformation processes, i.e., uniform deformation, localized necking, and failure imitation and propagation. Excellent pre-test prediction was shown for the burst-pressure test performed in 2006. Although cold-worked feeder bends have reduced fracture toughness compared to the parent straight pipe, post-test metallurgical examinations showed that failure at the

  18. LIFE Materials: Topical Assessment Report for LIFE Volume 1 TOPIC: Solid First Wall and Structural Components TASK: Radiation Effects on First Wall

    Energy Technology Data Exchange (ETDEWEB)

    Caro, A

    2008-11-26

    This report consists of the following chapters: CHAPTER A: LIFE Requirements for Materials. Part 1: The structure of the First Wall--Basic requirements; A qualitative view of the challenge; The candidate materials; and Base-line material's properties. CHAPTER B: Summary of Existing Knowledge--Brief historical introduction; Design window; The temperature window; Evolution of the design window with damage; Damage calculations; He and H production; Swelling resistance; Incubation dose for swelling; Design criterion No. 1, Strength; Design criterion No. 2, Corrosion resistance; Design criterion No. 3, Creep resistance; Design criterion No. 4, Radiation induced embrittlement; and Conclusions. CHAPTER C: Identification of Gaps in Knowledge & Vulnerabilities. CHAPTER D: Strategy and Future Work.

  19. 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 ...

  20. Industrially synthesized single-walled carbon nanotubes: compositional data for users, environmental risk assessments, and source apportionment

    Energy Technology Data Exchange (ETDEWEB)

    Plata, D L; Gschwend, P M [Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Reddy, C M [Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543 (United States)], E-mail: dplata@whoi.edu

    2008-05-07

    Commercially available single-walled carbon nanotubes (SWCNTs) contain large percentages of metal and carbonaceous impurities. These fractions influence the SWCNT physical properties and performance, yet their chemical compositions are not well defined. This lack of information also precludes accurate environmental risk assessments for specific SWCNT stocks, which emerging local legislation requires of nanomaterial manufacturers. To address these needs, we measured the elemental, molecular, and stable carbon isotope compositions of commercially available SWCNTs. As expected, catalytic metals occurred at per cent levels (1.3-29%), but purified materials also contained unexpected metals (e.g., Cu, Pb at 0.1-0.3 ppt). Nitrogen contents (up to 0.48%) were typically greater in arc-produced SWCNTs than in those derived from chemical vapor deposition. Toluene-extractable materials contributed less than 5% of the total mass of the SWCNTs. Internal standard losses during dichloromethane extractions suggested that metals are available for reductive dehalogenation reactions, ultimately resulting in the degradation of aromatic internal standards. The carbon isotope content of the extracted material suggested that SWCNTs acquired much of their carbonaceous contamination from their storage environment. Some of the SWCNTs, themselves, were highly depleted in {sup 13}C relative to petroleum-derived chemicals. The distinct carbon isotopic signatures and unique metal 'fingerprints' may be useful as environmental tracers allowing assessment of SWCNT sources to the environment.

  1. Drosophila embryos as model to assess cellular and developmental toxicity of multi-walled carbon nanotubes (MWCNT in living organisms.

    Directory of Open Access Journals (Sweden)

    Boyin Liu

    Full Text Available Different toxicity tests for carbon nanotubes (CNT have been developed to assess their impact on human health and on aquatic and terrestrial animal and plant life. We present a new model, the fruit fly Drosophila embryo offering the opportunity for rapid, inexpensive and detailed analysis of CNTs toxicity during embryonic development. We show that injected DiI labelled multi-walled carbon nanotubes (MWCNTs become incorporated into cells in early Drosophila embryos, allowing the study of the consequences of cellular uptake of CNTs on cell communication, tissue and organ formation in living embryos. Fluorescently labelled subcellular structures showed that MWCNTs remained cytoplasmic and were excluded from the nucleus. Analysis of developing ectodermal and neural stem cells in MWCNTs injected embryos revealed normal division patterns and differentiation capacity. However, an increase in cell death of ectodermal but not of neural stem cells was observed, indicating stem cell-specific vulnerability to MWCNT exposure. The ease of CNT embryo injections, the possibility of detailed morphological and genomic analysis and the low costs make Drosophila embryos a system of choice to assess potential developmental and cellular effects of CNTs and test their use in future CNT based new therapies including drug delivery.

  2. Analysis of autofrettaged metal tubes

    International Nuclear Information System (INIS)

    Malik, M. Afzaal; Khan, Muddasar; Rashid, Badar; Khushnood, Shahab

    2007-01-01

    Thick-walled cylinders are widely used as compressor cylinders, pump cylinders, high pressure tubing, process reactors and vessels, nuclear reactors, isostatic vessels and gun barrels. In practice, cylinders are generally subjected to sudden and frequently drastic pressure fluctuations, such as the pressure generated in a gun barrel upon the firing of the weapon, pressure reversals in pump cylinders or in process reactors employing high-pressure piping, necessitating enhanced strength of such cylinders. A process for enhancing the strength of thick-walled cylinders has been in service, and is referred to as 'autofrettage'. It extends the service life of the cylinder. The autofrettage is achieved by increasing elastic strength of a cylinder with various methods such as hydraulic pressurization, mechanical swaging, or by utilizing the pressure of a powder gas. This research work deals with the hydraulic and mechanical autofrettage of metal tubes with the objective to attain enhanced strength. Five metal tubes are taken randomly for analysis purpose. The experimental data for five metal tubes is obtained to analyze the behavior of different parameters used during, before, and after autofrettage process. For this research, two-stage autofrettage is taken into consideration. The modeling of the metal tube is carried out in WildFire-ProEngineering, and for analysis purpose, finite element software ANSYS7 and COSMOS are used. The graphical analysis of swage autofrettage is carried out using MATLAB7. The results are validated using available experimental and numerical data. (author)

  3. Identifying Measures Used for Assessing Quality of YouTube Videos with Patient Health Information: A Review of Current Literature.

    Science.gov (United States)

    Gabarron, Elia; Fernandez-Luque, Luis; Armayones, Manuel; Lau, Annie Ys

    2013-02-28

    Recent publications on YouTube have advocated its potential for patient education. However, a reliable description of what could be considered quality information for patient education on YouTube is missing. To identify topics associated with the concept of quality information for patient education on YouTube in the scientific literature. A literature review was performed in MEDLINE, ISI Web of Knowledge, Scopus, and PsychINFO. Abstract selection was first conducted by two independent reviewers; discrepancies were discussed in a second abstract review with two additional independent reviewers. Full text of selected papers were analyzed looking for concepts, definitions, and topics used by its authors that focused on the quality of information on YouTube for patient education. In total, 456 abstracts were extracted and 13 papers meeting eligibility criteria were analyzed. Concepts identified related to quality of information for patient education are categorized as expert-driven, popularity-driven, or heuristic-driven measures. These include (in descending order): (1) quality of content in 10/13 (77%), (2) view count in 9/13 (69%), (3) health professional opinion in 8/13 (62%), (4) adequate length or duration in 6/13 (46%), (5) public ratings in 5/13 (39%), (6) adequate title, tags, and description in 5/13 (39%), (7) good description or a comprehensive narrative in 4/13 (31%), (8) evidence-based practices included in video in 4/13 (31%), (9) suitability as a teaching tool in 4/13 (31%), (10) technical quality in 4/13 (31%), (11) credentials provided in video in 4/13 (31%), (12) enough amount of content to identify its objective in 3/13 (23%), and (13) viewership share in 2/13 (15%). Our review confirms that the current topics linked to quality of information for patient education on YouTube are unclear and not standardized. Although expert-driven, popularity-driven, or heuristic-driven measures are used as proxies to estimate the quality of video information

  4. CFD modeling of a boiler's tubes rupture

    International Nuclear Information System (INIS)

    Rahimi, Masoud; Khoshhal, Abbas; Shariati, Seyed Mehdi

    2006-01-01

    This paper reports the results of a study on the reason for tubes damage in the superheater Platen section of the 320 MW Bisotoun power plant, Iran. The boiler has three types of superheater tubes and the damage occurs in a series of elbows belongs to the long tubes. A three-dimensional modeling was performed using an in-house computational fluid dynamics (CFD) code in order to explore the reason. The code has ability of simultaneous solving of the continuity, the Reynolds-Averaged Navier-Stokes (RANS) equations and employing the turbulence, combustion and radiation models. The whole boiler including; walls, burners, air channels, three types of tubes, etc., was modeled in the real scale. The boiler was meshed into almost 2,000,000 tetrahedral control volumes and the standard k-ε turbulence model and the Rosseland radiation model were used in the model. The theoretical results showed that the inlet 18.9 MPa saturated steam becomes superheated inside the tubes and exit at a pressure of 17.8 MPa. The predicted results showed that the temperature of the steam and tube's wall in the long tubes is higher than the short and medium size tubes. In addition, the predicted steam mass flow rate in the long tube was lower than other ones. Therefore, it was concluded that the main reason for the rupture in the long tubes elbow is changing of the tube's metal microstructure due to working in a temperature higher than the design temperature. In addition, the structural fatigue tension makes the last elbow of the long tube more ready for rupture in comparison with the other places. The concluded result was validated by observations from the photomicrograph of the tube's metal samples taken from the damaged and undamaged sections

  5. Revision of orthovoltage chest wall treatment using Monte Carlo simulations.

    Science.gov (United States)

    Zeinali-Rafsanjani, B; Faghihi, R; Mosleh-Shirazi, M A; Mosalaei, A; Hadad, K

    2017-01-01

    Given the high local control rates observed in breast cancer patients undergoing chest wall irradiation by kilovoltage x-rays, we aimed to revisit this treatment modality by accurate calculation of dose distributions using Monte Carlo simulation. The machine components were simulated using the MCNPX code. This model was used to assess the dose distribution of chest wall kilovoltage treatment in different chest wall thicknesses and larger contour or fat patients in standard and mid sternum treatment plans. Assessments were performed at 50 and 100 cm focus surface distance (FSD) and different irradiation angles. In order to evaluate different plans, indices like homogeneity index, conformity index, the average dose of heart, lung, left anterior descending artery (LAD) and percentage target coverage (PTC) were used. Finally, the results were compared with the indices provided by electron therapy which is a more routine treatment of chest wall. These indices in a medium chest wall thickness in standard treatment plan at 50 cm FSD and 15 degrees tube angle was as follows: homogeneity index 2.57, conformity index 7.31, average target dose 27.43 Gy, average dose of heart, lung and LAD, 1.03, 2.08 and 1.60 Gy respectively and PTC 11.19%. Assessments revealed that dose homogeneity in planning target volume (PTV) and conformity between the high dose region and PTV was poor. To improve the treatment indices, the reference point was transferred from the chest wall skin surface to the center of PTV. The indices changed as follows: conformity index 7.31, average target dose 60.19 Gy, the average dose of heart, lung and LAD, 3.57, 6.38 and 5.05 Gy respectively and PTC 55.24%. Coverage index of electron therapy was 89% while it was 22.74% in the old orthovoltage method and also the average dose of the target was about 50 Gy but in the given method it was almost 30 Gy. The results of the treatment study show that the optimized standard and mid sternum treatment for different chest

  6. Assessment of Blasting Performance Using Electronic Vis-à-Vis Shock Tube Detonators in Strong Garnet Biotite Sillimanite Gneiss Formations

    Science.gov (United States)

    Sharma, Suresh Kumar; Rai, Piyush

    2016-04-01

    This paper presents a comparative investigation of the shock tube and electronic detonating systems practised in bench blasting. The blast trials were conducted on overburden rocks of Garnet Biotite Sillimanite Gneiss formations in one of the largest metalliferous mine of India. The study revealed that the choice of detonating system was crucial in deciding the fragment size and its distribution within the blasted muck-piles. The fragment size and its distribution affected the digging rate of excavators. Also, the shape of the blasted muck-pile was found to be related to the degree of fragmentation. From the present work, it may be inferred that in electronic detonation system, timely release of explosive energy resulted in better overall blasting performance. Hence, the precision in delay time must be considered in designing blast rounds in such overburden rock formations. State-of-art image analysis, GPS based muck-pile profile plotting techniques were rigorously used in the investigation. The study revealed that a mean fragment size (K50) value for shock tube detonated blasts (0.55-0.59 m) was higher than that of electronically detonated blasts (0.43-0.45 m). The digging rate of designated shovels (34 m3) with electronically detonated blasts was consistently more than 5000 t/h, which was almost 13 % higher in comparison to shock tube detonated blasts. Furthermore, favourable muck-pile shapes were witnessed in electronically detonated blasts from the observations made on the dozer performance.

  7. Assessing the prevalence of spina bifida and encephalocele in a Kenyan hospital from 2005–2010: implications for a neural tube defects surveillance system

    Science.gov (United States)

    Githuku, Jane N; Azofeifa, Alejandro; Valencia, Diana; Ao, Trong; Hamner, Heather; Amwayi, Samuel; Gura, Zeinab; Omolo, Jared; Albright, Leland; Guo, Jing; Arvelo, Wences

    2014-01-01

    Introduction Neural tube defects such as anencephaly, spina bifida, and encephalocele are congenital anomalies of the central nervous system. Data on the prevalence of neural tube defects in Kenya are limited. This study characterizes and estimates the prevalence of spina bifida and encephalocele reported in a referral hospital in Kenya from 2005-2010. Methods Cases were defined as a diagnosis of spina bifida or encephalocele. Prevalence was calculated as the number of cases by year and province of residence divided by the total number of live-births per province. Results From a total of 6,041 surgical records; 1,184 (93%) had reported diagnosis of spina bifida and 88 (7%) of encephalocele. Estimated prevalence of spina bifida and encephalocele from 2005-2010 was 3.3 [95% Confidence Interval (CI): 3.1-3.5] cases per 10,000 live-births. The highest prevalence of cases were reported in 2007 with 4.4 (95% CI: 3.9-5.0) cases per 10,000 live-births. Rift Valley province had the highest prevalence of spina bifida and encephalocele at 6.9 (95% CI: 6.3-7.5) cases per 10,000 live-births from 2005-2010. Conclusion Prevalence of spina bifida and encephalocele is likely underestimated, as only patients seeking care at the hospital were included. Variations in regional prevalence could be due to referral patterns and healthcare access. Implementation of a neural tube defects surveillance system would provide a more thorough assessment of the burden of neural tube defects in Kenya. PMID:26113894

  8. Assessing the prevalence of spina bifida and encephalocele in a Kenyan hospital from 2005-2010: implications for a neural tube defects surveillance system.

    Science.gov (United States)

    Githuku, Jane N; Azofeifa, Alejandro; Valencia, Diana; Ao, Trong; Hamner, Heather; Amwayi, Samuel; Gura, Zeinab; Omolo, Jared; Albright, Leland; Guo, Jing; Arvelo, Wences

    2014-01-01

    Neural tube defects such as anencephaly, spina bifida, and encephalocele are congenital anomalies of the central nervous system. Data on the prevalence of neural tube defects in Kenya are limited. This study characterizes and estimates the prevalence of spina bifida and encephalocele reported in a referral hospital in Kenya from 2005-2010. Cases were defined as a diagnosis of spina bifida or encephalocele. Prevalence was calculated as the number of cases by year and province of residence divided by the total number of live-births per province. From a total of 6,041 surgical records; 1,184 (93%) had reported diagnosis of spina bifida and 88 (7%) of encephalocele. Estimated prevalence of spina bifida and encephalocele from 2005-2010 was 3.3 [95% Confidence Interval (CI): 3.1-3.5] cases per 10,000 live-births. The highest prevalence of cases were reported in 2007 with 4.4 (95% CI: 3.9-5.0) cases per 10,000 live-births. Rift Valley province had the highest prevalence of spina bifida and encephalocele at 6.9 (95% CI: 6.3-7.5) cases per 10,000 live-births from 2005-2010. Prevalence of spina bifida and encephalocele is likely underestimated, as only patients seeking care at the hospital were included. Variations in regional prevalence could be due to referral patterns and healthcare access. Implementation of a neural tube defects surveillance system would provide a more thorough assessment of the burden of neural tube defects in Kenya.

  9. The PISC programme on defective steam generator tubes inspection. A status report

    International Nuclear Information System (INIS)

    Birac, C.; Comby, R.; Maciga, G.; Von Estorff, U.; Zanella, G.L.

    1994-06-01

    The general objective of the PISC Program (Programme for the Inspection of Steel Components) is to assess experimentally procedures and techniques in use for the in-service inspection of pressure components. The program is mainly a round robin test, the results of which are compared with real characteristics of the flaws obtained by destructive analysis. Materials tested are INCONEL 600 tubes, diameter 22.22 mm, wall thickness 1.27 mm. The technique applied is eddy current testing. The program of capability tests on loose tubes was started in 1990, the round robin tests ended in 1993. The preliminary results are presented. (R.P.). 8 refs., 9 figs., 4 tabs

  10. Electron tube

    Science.gov (United States)

    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.

  11. A Study on the Development of Nonglass Solar Vacuum Tube Collector

    International Nuclear Information System (INIS)

    Oh, Seung Jin

    2008-02-01

    Nature has been providing us energy from the beginning of the world. However human has hardly used it wisely. Solar energy is a kind of renewable energy from the nature. This study has been carried out to study the use of solar energy as it is harnessed in the form of thermal energy. Solar energy is one of the most promising energy resources such as hydrogen, biomass, wind and geothermal energy, because it is clean and inexhaustible. Space heating in buildings can be provided from solar energy by systems that are similar in many respects to water heater systems. By tapping into solar energy, we can not only solve the problem of energy shortage, but also can protect the environment and benefit the human beings. There are currently two types of evacuated tube; a single glass tube and a double glass tube. The former consists of a single glass tube which contains a flat or curved aluminium plate attached to a copper heat pipe or water flow pipe. The latter consists of rows of parallel transparent glass tubes, each of which contains an absorber tube. Evacuated tube collectors introduced above, however, pose some problems as they break rather easily under mechanical stresses. This paper introduces some preliminary results in design and fabrication of a non-glass solar vacuum tube collector in which the thermosyphon(heat pipe)made of copper is used as a heat transfer device. A series of tests have been performed to assess the ability of a non-glass solar vacuum tube collector. The series of experiments are as follows: 1)Vacuum level inside a vacuum tube. 2)Effects of the air remaining inside a vacuum tube on the temperature on the absorber plate. 3)Comparison of a non-glass vacuum solar collector with a single glass evacuated tube(SEIDO 5). Different vacuum levels inside non-glass vacuum tubes were applied to check any leakage or unexpected physical or chemical developments with time. The vacuum level changed from 10 -2 torr to 5torr in 5 days due to air infiltration from

  12. Heat treated tube for cladding nuclear fuel element

    International Nuclear Information System (INIS)

    Eddens, F.C.; White, D.W.; Harmon, J.L.

    1983-01-01

    The zirconium alloy tube comprises a metallurgical gradient across the width of the tube wall wherein the tube has a more corrosion-resistant metallurgical condition at the outer circumference and a less corrosion-resistant metallurgical condition at the inner circumference. The metallurgical gradient can be generated by heating an outer circumferential portion of the tube to the high alpha or mixed alpha plus beta range while maintaining the inner surface at a lower temperature, followed by cooling of the tube. Preferably the tube is made of Zircaloy. (author)

  13. Cell wall assembly and intracellular trafficking in plant cells are directly affected by changes in the magnitude of gravitational acceleration.

    Directory of Open Access Journals (Sweden)

    Youssef Chebli

    Full Text Available Plants are able to sense the magnitude and direction of gravity. This capacity is thought to reside in selected cell types within the plant body that are equipped with specialized organelles called statoliths. However, most plant cells do not possess statoliths, yet they respond to changes in gravitational acceleration. To understand the effect of gravity on the metabolism and cellular functioning of non-specialized plant cells, we investigated a rapidly growing plant cell devoid of known statoliths and without gravitropic behavior, the pollen tube. The effects of hyper-gravity and omnidirectional exposure to gravity on intracellular trafficking and on cell wall assembly were assessed in Camellia pollen tubes, a model system with highly reproducible growth behavior in vitro. Using an epi-fluorescence microscope mounted on the Large Diameter Centrifuge at the European Space Agency, we were able to demonstrate that vesicular trafficking is reduced under hyper-gravity conditions. Immuno-cytochemistry confirmed that both in hyper and omnidirectional gravity conditions, the characteristic spatial profiles of cellulose and callose distribution in the pollen tube wall were altered, in accordance with a dose-dependent effect on pollen tube diameter. Our findings suggest that in response to gravity induced stress, the pollen tube responds by modifying cell wall assembly to compensate for the altered mechanical load. The effect was reversible within few minutes demonstrating that the pollen tube is able to quickly adapt to changing stress conditions.

  14. Chest tube insertion

    Science.gov (United States)

    Chest drainage tube insertion; Insertion of tube into chest; Tube thoracostomy; Pericardial drain ... Be careful there are no kinks in your tube. The drainage system should always sit upright and be placed ...

  15. Dynamics of explosively imploded pressurized tubes

    Science.gov (United States)

    Szirti, Daniel; Loiseau, Jason; Higgins, Andrew; Tanguay, Vincent

    2011-04-01

    The detonation of an explosive layer surrounding a pressurized thin-walled tube causes the formation of a virtual piston that drives a precursor shock wave ahead of the detonation, generating very high temperatures and pressures in the gas contained within the tube. Such a device can be used as the driver for a high energy density shock tube or hypervelocity gas gun. The dynamics of the precursor shock wave were investigated for different tube sizes and initial fill pressures. Shock velocity and standoff distance were found to decrease with increasing fill pressure, mainly due to radial expansion of the tube. Adding a tamper can reduce this effect, but may increase jetting. A simple analytical model based on acoustic wave interactions was developed to calculate pump tube expansion and the resulting effect on the shock velocity and standoff distance. Results from this model agree quite well with experimental data.

  16. Pressure tube reactor

    International Nuclear Information System (INIS)

    Kanazawa, Nobuhiro; Kaneto, Kunikazu.

    1979-01-01

    Purpose: To attain uniform fluid poison distribution in a calandria tank by downwardly projecting, at an equal distance to the reactor core, a spacer wall from the periphery of an anti-vibration plate in the vicinity of a heavy water flow passage in the periphery of the anti-vibration plate, thereby decrease the amount of heavy water flowing into the heavy water flow passage. Constitution: A projecting wall concentrical with a calandria tank is suspended vertically from the boundary side at the peripheral portion of an anti-vibration plate to a water heavy flow passage in the periphery of the anti-vibration plate. The projecting wall has such a vertical length as about equal to the width of the heavy water flow passage, prevents heavy water flowing through apertures of a control rod guide tube from entering into the heavy water passage and increases the ratio of heavy water that flows through the heavy water flow passage in the anti-vibration plate. Consequently, if the liquid poison density in heavy water is varied, the ununiform poison density in the calandria tank can be prevented. (Seki, T.)

  17. Influence of radiation dose and reconstruction algorithm in MDCT assessment of airway wall thickness: A phantom study

    International Nuclear Information System (INIS)

    Gomez-Cardona, Daniel; Nagle, Scott K.; Li, Ke; Chen, Guang-Hong; Robinson, Terry E.

    2015-01-01

    Purpose: Wall thickness (WT) is an airway feature of great interest for the assessment of morphological changes in the lung parenchyma. Multidetector computed tomography (MDCT) has recently been used to evaluate airway WT, but the potential risk of radiation-induced carcinogenesis—particularly in younger patients—might limit a wider use of this imaging method in clinical practice. The recent commercial implementation of the statistical model-based iterative reconstruction (MBIR) algorithm, instead of the conventional filtered back projection (FBP) algorithm, has enabled considerable radiation dose reduction in many other clinical applications of MDCT. The purpose of this work was to study the impact of radiation dose and MBIR in the MDCT assessment of airway WT. Methods: An airway phantom was scanned using a clinical MDCT system (Discovery CT750 HD, GE Healthcare) at 4 kV levels and 5 mAs levels. Both FBP and a commercial implementation of MBIR (Veo TM , GE Healthcare) were used to reconstruct CT images of the airways. For each kV–mAs combination and each reconstruction algorithm, the contrast-to-noise ratio (CNR) of the airways was measured, and the WT of each airway was measured and compared with the nominal value; the relative bias and the angular standard deviation in the measured WT were calculated. For each airway and reconstruction algorithm, the overall performance of WT quantification across all of the 20 kV–mAs combinations was quantified by the sum of squares (SSQs) of the difference between the measured and nominal WT values. Finally, the particular kV–mAs combination and reconstruction algorithm that minimized radiation dose while still achieving a reference WT quantification accuracy level was chosen as the optimal acquisition and reconstruction settings. Results: The wall thicknesses of seven airways of different sizes were analyzed in the study. Compared with FBP, MBIR improved the CNR of the airways, particularly at low radiation dose

  18. Influence of radiation dose and reconstruction algorithm in MDCT assessment of airway wall thickness: A phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Cardona, Daniel [Department of Medical Physics, University of Wisconsin-Madison School of Medicine and Public Health, 1111 Highland Avenue, Madison, Wisconsin 53705 (United States); Nagle, Scott K. [Department of Medical Physics, University of Wisconsin-Madison School of Medicine and Public Health, 1111 Highland Avenue, Madison, Wisconsin 53705 (United States); Department of Radiology, University of Wisconsin-Madison School of Medicine and Public Health, 600 Highland Avenue, Madison, Wisconsin 53792 (United States); Department of Pediatrics, University of Wisconsin-Madison School of Medicine and Public Health, 600 Highland Avenue, Madison, Wisconsin 53792 (United States); Li, Ke; Chen, Guang-Hong, E-mail: gchen7@wisc.edu [Department of Medical Physics, University of Wisconsin-Madison School of Medicine and Public Health, 1111 Highland Avenue, Madison, Wisconsin 53705 (United States); Department of Radiology, University of Wisconsin-Madison School of Medicine and Public Health, 600 Highland Avenue, Madison, Wisconsin 53792 (United States); Robinson, Terry E. [Department of Pediatrics, Stanford School of Medicine, 770 Welch Road, Palo Alto, California 94304 (United States)

    2015-10-15

    Purpose: Wall thickness (WT) is an airway feature of great interest for the assessment of morphological changes in the lung parenchyma. Multidetector computed tomography (MDCT) has recently been used to evaluate airway WT, but the potential risk of radiation-induced carcinogenesis—particularly in younger patients—might limit a wider use of this imaging method in clinical practice. The recent commercial implementation of the statistical model-based iterative reconstruction (MBIR) algorithm, instead of the conventional filtered back projection (FBP) algorithm, has enabled considerable radiation dose reduction in many other clinical applications of MDCT. The purpose of this work was to study the impact of radiation dose and MBIR in the MDCT assessment of airway WT. Methods: An airway phantom was scanned using a clinical MDCT system (Discovery CT750 HD, GE Healthcare) at 4 kV levels and 5 mAs levels. Both FBP and a commercial implementation of MBIR (Veo{sup TM}, GE Healthcare) were used to reconstruct CT images of the airways. For each kV–mAs combination and each reconstruction algorithm, the contrast-to-noise ratio (CNR) of the airways was measured, and the WT of each airway was measured and compared with the nominal value; the relative bias and the angular standard deviation in the measured WT were calculated. For each airway and reconstruction algorithm, the overall performance of WT quantification across all of the 20 kV–mAs combinations was quantified by the sum of squares (SSQs) of the difference between the measured and nominal WT values. Finally, the particular kV–mAs combination and reconstruction algorithm that minimized radiation dose while still achieving a reference WT quantification accuracy level was chosen as the optimal acquisition and reconstruction settings. Results: The wall thicknesses of seven airways of different sizes were analyzed in the study. Compared with FBP, MBIR improved the CNR of the airways, particularly at low radiation dose

  19. An in vitro comparison of tracheostomy tube cuffs

    Directory of Open Access Journals (Sweden)

    Maguire S

    2015-04-01

    Full Text Available Seamus Maguire,1 Frances Haury,2 Korinne Jew2 1Research and Development, Covidien Respiratory and Monitoring Solutions, Athlone, Ireland; 2Medical Affairs, Covidien Respiratory and Monitoring Solutions, Boulder, CO, USA Introduction: The Shiley™ Flexible adult tracheostomy tube with TaperGuard™ cuff has been designed through its geometry, materials, diameter, and wall thickness to minimize micro-aspiration of fluids past the cuff and to provide an effective air seal in the trachea while also minimizing the risk of excessive contact pressure on the tracheal mucosa. The cuff also has a deflated profile that may allow for easier insertion through the stoma site. This unique design is known as the TaperGuard™ cuff. The purpose of the observational, in vitro study reported here was to compare the TaperGuard™ taper-shaped cuff to a conventional high-volume low-pressure cylindrical-shaped cuff (Shiley™ Disposable Inner Cannula Tracheostomy Tube [DCT] with respect to applied tracheal wall pressure, air and fluid sealing efficacy, and insertion force.Methods: Three sizes of tracheostomy tubes with the two cuff types were placed in appropriately sized tracheal models and lateral wall pressure was measured via pressure-sensing elements on the inner surface. Fluid sealing performance was assessed by inflating the cuffs within the tracheal models (25 cmH2O, instilling water above the cuff, and measuring fluid leakage past the cuff. To measure air leak, tubes were attached to a test lung and ventilator, and leak was calculated by subtracting the average exhaled tidal volume from the average delivered tidal volume. A tensile test machine was used to measure insertion force for each tube with the cuff deflated to simulate clinical insertion through a stoma site.Results: The average pressure exerted on the lateral wall of the model trachea was lower for the taper-shaped cuff than for the cylindrical cuff under all test conditions (P<0.05. The taper

  20. Criteria of assessment for local wall thickness reductions in operative high-pressure gas pipelines; Beurteilungskriterien fuer lokale Wanddickenminderungen an in Betrieb befindlichen Gashochdruckleitungen

    Energy Technology Data Exchange (ETDEWEB)

    Hass, Georg [NetzDienste Rhein/Main GmbH, Frankfurt am Main (Germany); Hoffman, Ulrich [VNG - Verbundnetz Gas AG, Leipzig (Germany); Konarske, Juergen [RWE Westfalen-Weser-Ems Netzservice GmbH, Recklinghausen (Germany); Soppa, Thorsten [NG Netz Gas+Wasser (Germany). Bau/Betrieb Hochdrucknetz; Steiner, Michael [Open Grid Europe GmbH, Essen (Germany). Integritaet/Werkstofftechnik

    2011-07-01

    TUeV Nord, Salzgitter Mannesmann Forschung and DVGW investigated methods to assess local wall thickness reductions in operative high-pressure gas pipelines. Methods described in the relevant literature were reviewed with regard to the limiting criteria defined for maximum permissible wall thickness reductions. On the basis of this literature study and additional calculations, a comparative evaluation of the available methods was made. Several methods were identified that are compatible with the existing safety concept and general availability. It was found that - nearly independent of the method - burst safeties of 1.8 to 2.0 were used. The ultimate goal is the development of a German standard evaluation concept for local wall thickness reductions in high-pressure gas pipelines in order to avoid uncertainties and/or misinterpretations.

  1. Can the lifetime of the superheater tubes be predicted according to the fuel analyses? Assessment from field and laboratory data

    Energy Technology Data Exchange (ETDEWEB)

    Salmenoja, K. [Kvaerner Pulping Oy, Tampere (Finland)

    1998-12-31

    Lifetime of the superheaters in different power boilers is more or less still a mystery. This is especially true in firing biomass based fuels (biofuels), such as bark, forest residues, and straw. Due to the unhomogeneous nature of the biofuels, the lifetime of the superheaters may vary from case to case. Sometimes the lifetime is significantly shorter than originally expected, sometimes no corrosion even in the hottest tubes is observed. This is one of the main reasons why the boiler operators often demand for a better predictability on the corrosion resistance of the materials to avoid unscheduled shutdowns. (orig.) 9 refs.