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Sample records for fung double tube

  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. Free Piston Double Diaphragm Shock Tube

    OpenAIRE

    OGURA, Eiji; FUNABIKI, Katsushi; SATO, Shunichi; ABE, Takashi; 小倉, 栄二; 船曳, 勝之; 佐藤, 俊逸; 安部, 隆士

    1997-01-01

    A free piston double diaphragm shock tube was newly developed for generation of high Mach number shock wave. Its characteristics was investigated for various operation parameters; such as a strength of the diaphragm at the end of the comparession tube, an initial pressure of low pressure tube, an initial pressure of medium pressure tube and the volume of compression tube. Under the restriction of fixed pressures for the driver high pressure tube (32×10^5Pa) and the low pressure tube (40Pa) in...

  3. 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.

  4. Fast, global, and entrepreneurial: supply chain management, Hong Kong style. An interview with Victor Fung. Interview by Joan Magretta.

    Science.gov (United States)

    Fung, V

    1998-01-01

    Li & Fung, Hong Kong's largest export trading company, has been an innovator in supply chain management--a topic of increasing importance to many senior executives. In this interview, chairman Victor Fung explains both the philosophy behind supply chain management and the specific practices that Li & Fung has developed to reduce costs and lead times, allowing its customers to buy "closer to the market." Li & Fung has been a pioneer in "dispersed manufacturing." It performs the higher-value-added tasks such as design and quality control in Hong Kong, and outsources the lower-value-added tasks to the best possible locations around the world. The result is something new: a truly global product. To produce a garment, for example, the company might purchase yarn from Korea that will be woven and dyed in Taiwan, then shipped to Thailand for final assembly, where it will be matched with zippers from a Japanese company. For every order, the goal is to customize the value chain to meet the customer's specific needs. To be run effectively, Victor Fung maintains, trading companies have to be small and entrepreneurial. He describes the organizational approaches that keep the company that way despite its growing size and geographic scope: its organization around small, customer-focused units; its incentives and compensation structure; and its use of venture capital as a vehicle for business development. As Asia's economic crisis continues, chairman Fung sees a new model of companies emerging--companies that are, like Li & Fung, narrowly focused and professionally managed.

  5. 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

  6. Performance analysis of double basin solar still with evacuated tubes

    International Nuclear Information System (INIS)

    Hitesh N Panchal; Shah, P. K.

    2013-01-01

    Solar still is a very simple device, which is used for solar distillation process. In this research work, double basin solar still is made from locally available materials. Double basin solar still is made in such a way that, outer basin is exposed to sun and lower side of inner basin is directly connected with evacuated tubes to increase distillate output and reducing heat losses of a solar still. The overall size of the lower basin is about 1006 mm x 325 mm x 380 mm, the outer basin is about 1006 mm x 536 mm x 100 mm Black granite gravel is used to increase distillate output by reducing quantity of brackish or saline water in the both basins. Several experiments have conducted to determine the performance of a solar still in climate conditions of Mehsana (latitude of 23 degree 59' and longitude of 72 degree 38'), Gujarat, like a double basin solar still alone, double basin solar still with different size black granite gravel, double basin solar still with evacuated tubes and double basin solar still with evacuated tubes and different size black granite gravel. Experimental results show that, connecting evacuated tubes with the lower side of the inner basin increases daily distillate output of 56% and is increased by 60%, 63% and 67% with average 10 mm, 20 mm and 30 mm size black granite gravel. Economic analysis of present double basin solar still is 195 days. (authors)

  7. Analysis of the heat transfer in double and triple concentric tube heat exchangers

    Science.gov (United States)

    Rădulescu, S.; Negoiţă, L. I.; Onuţu, I.

    2016-08-01

    The tubular heat exchangers (shell and tube heat exchangers and concentric tube heat exchangers) represent an important category of equipment in the petroleum refineries and are used for heating, pre-heating, cooling, condensation and evaporation purposes. The paper presents results of analysis of the heat transfer to cool a petroleum product in two types of concentric tube heat exchangers: double and triple concentric tube heat exchangers. The cooling agent is water. The triple concentric tube heat exchanger is a modified constructive version of double concentric tube heat exchanger by adding an intermediate tube. This intermediate tube improves the heat transfer by increasing the heat area per unit length. The analysis of the heat transfer is made using experimental data obtained during the tests in a double and triple concentric tube heat exchanger. The flow rates of fluids, inlet and outlet temperatures of water and petroleum product are used in determining the performance of both heat exchangers. Principally, for both apparatus are calculated the overall heat transfer coefficients and the heat exchange surfaces. The presented results shows that triple concentric tube heat exchangers provide better heat transfer efficiencies compared to the double concentric tube heat exchangers.

  8. Heat transfer in laminar flow for a finned double - tube

    International Nuclear Information System (INIS)

    Colle, S.

    1977-01-01

    An analitical study of the steady-state heat transfer in laminar flow in finned double-tube heat exchangers is presented. The fins are plane, straight and continous, equally spaced and are fixed over the external surface of the inner tube. A constant peripheral temperature distribution is assumed to apply over the inner tube surface and each fin, and a constant peripheral heat flux is assumed to apply over the outer tube surface, while the overall heat flux is suposed to be uniform in the longitudinal direction of the duct. The prediction of the thermal performance of the finned double-tube is made by means of the relationship between the Nusselt number, the boundary conditions and the geometric characteristcs of the duct. (author) [pt

  9. 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)

  10. Analysis of DC control in double-inlet GM type pulse tube refrigerators for detectors

    Science.gov (United States)

    Du, B. Y.

    2016-10-01

    Pulse tube refrigerators have demonstrated many advantages with respect to temperature stability, vibration, reliability and lifetime among cryo-coolers for detectors. Double-inlet type pulse tube refrigerators are popular in GM type pulse tube refrigerators. The single double-inlet valve may introduce DC flow in refrigerator, which deteriorates the performance of pulse tube refrigerator. One new type of DC control mode is introduced in this paper. Two parallel-placed needle valves with opposite direction named double-valve configuration, instead of single double-inlet valve, are used in our experiment to reduce the DC flow. With two double-inlet operating, the lowest cold end temperature of 18.1K and a coolant of 1.2W@20K have been obtained. It has proved that this method is useful for controlling DC flow of the pulse tube refrigerators, which is very important to understand the characters of pulse tube refrigerators for detectors.

  11. Bestimmung der optimalen Array-Apertur für die Ultraschallprüfung von faserverstärkten Kunststoffen

    OpenAIRE

    Kurras, Martin

    2017-01-01

    Für die zerstörungsfreie Prüfung von Kohlenstofffaserverbundwerkstoffen (CFK) wird häufig die Ultraschallprüfung verwendet. Neben dem klassischen Ultraschallverfahren findet dabei auch die Phased Array Technologie Anwendung. Hierbei wird zwischen zwei Verfahren unterschieden: dem handelsüblichen Phased Array oder Conventional Phased Array (CPA) und dem tomographischen Sampling Phased Array (SPA). Der Einsatz von Phased Arrays im Zusammenhang mit Linear-Scan-Technik und das sich daraus ergeben...

  12. 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)

  13. 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)

  14. Experimental study for transient response of a double-tube thermosyphon (DTTH)

    International Nuclear Information System (INIS)

    Salem, M.A.M.

    2010-01-01

    Energy conservation is becoming increasingly important as the cost of fuel continuously rises. The heat pipe and the closed two-phase thermosyphon are particularly effective tools in the heat transfer process.A theoretical and experimental investigation was conducted to study the double-tube two-phase closed-thermosyphon (DTTH) behavior in transient regimes. Experiments were performed to investigate the effects of changing the heating and cooling rate as well as the evaporator length on the double tube thermosyphon in actual integrated operation (start-up, steady-state and shut-down). he necessity for a dynamic model of DTTH for some applications of discontinuous operation imposed the need to the current applied investigation. Therefore, the main objective of the current study is to develop a theoretical model that can predict the dynamic behavior of the double-tube evaporator by tracing various transient parameters during operation from start up to steady state until shut down condition. A model describing both thermal and phase flows of the closed two-phase double tube thermosyphon (DTTH) has been simulated. The theoretical model provides a general description of the behavior of our practical setup based on experimental observations which show a simple exponential behavior. It is based on a two thermal body description (evaporator wall and working fluid) there is good agreement between experiments data and numerical prediction.A computer simulation program based on the method was developed to estimate temperature and the other performance of double tube thermosyphon as well as the time needed to reach steady state condition. The governing equations of the simple 1-D model were solved by Engineering Equation Solver program (EES) using finite difference Euler method. A computer program is designed to solve these differential equations by an explicit finite difference method. The results from this model were found to be in general agreement with the experimental

  15. Investigation of FIV Characteristics on a Coaxial Double-tube Structure

    Energy Technology Data Exchange (ETDEWEB)

    Song, Kee Nam; Kim, Yong Wan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Sang Chul [ABLEMAX Co., Seoul (Korea, Republic of)

    2009-10-15

    A Very High Temperature Gas Cooled Reactor (VHTR) has been selected as a high energy heat source of the order of 950 .deg. C for nuclear hydrogen generation, which can produce hydrogen from water or natural gas. A primary hot gas duct (HGD) as a coaxial double-tube type cross vessel is a key component connecting a reactor pressure vessel and an intermediate heat exchanger in the VHTR. In this study, a structural sizing methodology for the primary HGD of the VHTR is suggested in order to modulate a flow-induced vibration (FIV). And as an example, a structural sizing of the horizontal HGD with a coaxial double-tube structure was carried out using the suggested method. These activities include a decision of the geometric dimensions, a selection of the material, and an evaluation of the strength of the coaxial double-tube type cross vessel components. Also in order to compare the FIV characteristics of the proposed design cases, a fluid-structure interaction (FSI) analysis was carried out using the ADINA code.

  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. Core design of super LWR with double tube water rods

    International Nuclear Information System (INIS)

    Wu, Jianhui; Oka, Yoshiaki

    2014-01-01

    Highlights: • Supercritical light water cooled and moderated reactor with double tube water rods is developed. • Double-row fuel rod assembly and out-in fuel loading pattern are applied. • Separation plates in peripheral assemblies increase average outlet temperature. • Neutronic and thermal design criteria are satisfied during the cycle. - Abstract: Double tube water rods are employed in core design of super LWR to simplify the upper core structure and refueling procedure. The light water moderator flows up in the inner tube from the bottom of the core, then, changes the flow direction at the top of the core into the outer tube and flows out at the bottom of the core. It eliminates the moderator guide/distribution tubes into the single tube water rods from the top dome of the reactor pressure vessel of the previous super LWR design. Two rows of fuel rods are filled between the water rods in the fuel assembly. Out-in refueling pattern is adopted to flatten radial power distribution. The peripheral fuel assemblies of the core are divided into four flow zones by separation plates for increasing the average core outlet temperature. Three enrichment zones are used for axial power flattening. The equilibrium core is analyzed based on neutronic/thermal-hydraulic coupled model. The results show that, by applying the separation plates in peripheral fuel assemblies and low gadolinia enrichment, the maximum cladding surface temperature (MCST) is limited to 653 °C with the average outlet temperature of 500 °C. The inherent safety is satisfied by the negative void reactivity effects and sufficient shutdown margin

  18. Influence of a Double-Lumen Extension Tube on Drug Delivery: Examples of Isosorbide Dinitrate and Diazepam.

    Directory of Open Access Journals (Sweden)

    Aurélie Maiguy-Foinard

    Full Text Available Plastic materials such as polyurethane (PUR, polyethylene (PE, polypropylene (PP and polyvinyl chloride (PVC are widely used in double-lumen extension tubing. The purposes of our study were to 1 compare in vitro drug delivery through the double extension tubes available on the market 2 assess the plastic properties of PUR in infusion devices and their impact on drug delivery.The study compared eight double-lumen extension tubes in PUR, co-extruded (PE/PVC plastic and plasticised PVC from different manufacturers. Isosorbide dinitrate and diazepam were used as model compounds to evaluate their sorption on the internal surface of the infusion device. Control experiments were performed using norepinephrine known not to absorb to plastics. Drug concentrations delivered at the egress of extension tubes were determined over time by an analytical spectrophotometric UV-Vis method. The main characteristics of plastics were also determined.Significant differences in the sorption phenomenon were observed among the eight double-lumen extension tubes and between pairs of extension tubes. Mean concentrations of isosorbide dinitrate delivered at the egress of double-lumen extension tubes after a 150-minute infusion (mean values ± standard deviation in percentage of the initial concentrations in the prepared syringes ranged between 80.53 ± 1.66 (one of the PUR tubes and 92.84 ± 2.73 (PE/PVC tube. The same parameters measured during diazepam infusion ranged between 48.58 ± 2.88 (one of the PUR tubes and 85.06 ± 3.94 (PE/PVC tube. The double-lumen extension tubes in PUR were either thermosetting (resin or thermoplastic according to reference.Clinicians must be aware of potential drug interactions with extension tube materials and so must consider their nature as well as the sterilisation method used before selecting an infusion device.

  19. The single chest tube versus double chest tube application after pulmonary lobectomy: A systematic review and meta-analysis

    Directory of Open Access Journals (Sweden)

    Xuefei Zhang

    2016-01-01

    Conclusion: Compared with the double chest tube, the single chest tube significantly decreases amount of drainage, duration of chest tube drainage, pain score, the number of patients who need thoracentesis, and cost. Although there is convincing evidence to confirm the results mentioned herein, they still need to be confirmed by large-sample, multicenter, randomized, controlled trials.

  20. Fluoroscopic guidance for placing a double lumen endotracheal tube in adults.

    Science.gov (United States)

    Calenda, Emile; Baste, Jean Marc; Hajjej, Ridha; Rezig, Najiba; Moriceau, Jerome; Diallo, Yaya; Sghaeir, Slim; Danielou, Eric; Peillon, Christophe

    2014-09-01

    The aim of this study was to assess the right placement of the double lumen endotracheal tube with fluoroscopic guidance, which is used in first intention prior to the fiberscope in our institution. This was a prospective observational study. The study was conducted in vascular and thoracic operating rooms. We enrolled 205 patients scheduled for thoracic surgery, with ASA physical statuses of I (n = 37), II (n = 84), III (n = 80), and IV (n = 4). Thoracic procedures were biopsy (n = 20), wedge (n = 34), culminectomy (n = 6), lobectomy (n = 82), pneumonectomy (n = 4), sympathectomy (n = 9), symphysis (n = 47), and thymectomy (n = 3). The intubation with a double lumen tube was performed with the help of a laryngoscope. Tracheal and bronchial balloons were inflated and auscultation was performed after right and left exclusions. One shot was performed to locate the position of the bronchial tube and the hook. Fluoroscopic guidance was used to relocate the tube in case of a wrong position. When the fluoroscopic guidance failed to position the tube, a fiberscope was used. Perioperative collapse of the lung was assessed by the surgeon during the surgery. Correct fluoroscopic image was obtained after the first attempt in 58.5% of patients therefore a misplaced position was encountered in 41.5%. The fluoroscopic guidance allowed an exact repositioning in 99.5% of cases, and the mean duration of the procedure was 8 minutes. A fiberscope was required to move the hook for one patient. We did not notice a moving of the double lumen endotracheal tube during the surgery. The surgeon satisfaction was 100%. The fluoroscopy evidenced the right position of the double lumen tube and allowed a right repositioning in 99.5% of patients with a very simple implementation. Copyright © 2014. Published by Elsevier B.V.

  1. Single chest tube drainage is superior to double chest tube drainage after lobectomy: a meta-analysis.

    Science.gov (United States)

    Zhou, Dong; Deng, Xu-Feng; Liu, Quan-Xing; Chen, Qian; Min, Jia-Xin; Dai, Ji-Gang

    2016-05-27

    In this meta-analysis, we conducted a pooled analysis of clinical studies comparing the efficacy of single chest tube versus double chest tube after a lobectomy. According to the recommendations of the Cochrane Collaboration, we established a rigorous study protocol. We performed a systematic electronic search of the PubMed, Embase, Cochrane Library and Web of Science databases to identify articles to include in our meta-analysis. A literature search was performed using relevant keywords. A meta-analysis was performed using RevMan© software. Five studies, published between 2003 and 2014, including 630 patients (314 patients with a single chest tube and 316 patients with a double chest tube), met the selection criteria. From the available data, the patients using a single tube demonstrated significantly decreased postoperative pain [weighted mean difference [WMD] -0.60; 95 % confidence intervals [CIs] -0.68-- 0.52; P tube after a pulmonary lobectomy. However, there were no significant differences in postoperative complications [OR 0.91; 95 % CIs 0.57-1.44; P = 0.67] and re-drainage rates [OR 0.81; 95 % CIs 0.42-1.58; P = 0.54]. Our results showed that a single-drain method is effective, reducing postoperative pain, hospitalization times and duration of drainage in patients who undergo a lobectomy. Moreover, the single-drain method does not increase the occurrence of postoperative complications and re-drainage rates.

  2. Thermal optimization of primary side in double-tube OTSG

    International Nuclear Information System (INIS)

    Wei Xinyu; Dai Chunhui; Hou Suxia; Tai Yun; Zhao Fuyu

    2011-01-01

    Once-through steam generator (OTSG) is usually used in the integrated nuclear power plants which require smaller volume and better effect of heat transfer. The double-tube OTSG component which is composed of straight tube outside and helical tube inside is presented in this paper. The primary fluid is divided into two parts, one is in the inner tube and the other is in the gap among outer tubes. The flow distribution ratio of the primary fluid obviously affects the heat transfer. Thus, the problem of optimization emerges, i.e. how to find an optimal flow distribution ratio with a maximum heat exchange. Analyzed the effects of the distribution ratio on heat transfer, the optimal distribution ratio is obtained by the constrained nonlinear optimization method. Subsequently, the optimal distribution ratio is achieved by a throttling set in the entrance of the inner tube. The result is in substantial agreement with the literature. (author)

  3. Preliminary Study on Biosynthesis of Bacterial Nanocellulose Tubes in a Novel Double-Silicone-Tube Bioreactor for Potential Vascular Prosthesis

    Directory of Open Access Journals (Sweden)

    Feng Hong

    2015-01-01

    Full Text Available Bacterial nanocellulose (BNC has demonstrated a tempting prospect for applications in substitute of small blood vessels. However, present technology is inefficient in production and BNC tubes have a layered structure that may bring danger after implanting. Double oxygen-permeable silicone tubes in different diameters were therefore used as a tube-shape mold and also as oxygenated supports to construct a novel bioreactor for production of the tubular BNC materials. Double cannula technology was used to produce tubular BNC via cultivations with Acetobacter xylinum, and Kombucha, a symbiosis of acetic acid bacteria and yeasts. The results indicated that Kombucha gave higher yield and productivity of BNC than A. xylinum. Bacterial nanocellulose was simultaneously synthesized both on the inner surface of the outer silicone tube and on the outer surface of the inner silicone tube. Finally, the nano BNC fibrils from two directions formed a BNC tube with good structural integrity. Scanning electron microscopy inspection showed that the tubular BNC had a multilayer structure in the beginning but finally it disappeared and an intact BNC tube formed. The mechanical properties of BNC tubes were comparable with the reported value in literatures, demonstrating a great potential in vascular implants or in functional substitutes in biomedicine.

  4. Preliminary Study on Biosynthesis of Bacterial Nanocellulose Tubes in a Novel Double-Silicone-Tube Bioreactor for Potential Vascular Prosthesis.

    Science.gov (United States)

    Hong, Feng; Wei, Bin; Chen, Lin

    2015-01-01

    Bacterial nanocellulose (BNC) has demonstrated a tempting prospect for applications in substitute of small blood vessels. However, present technology is inefficient in production and BNC tubes have a layered structure that may bring danger after implanting. Double oxygen-permeable silicone tubes in different diameters were therefore used as a tube-shape mold and also as oxygenated supports to construct a novel bioreactor for production of the tubular BNC materials. Double cannula technology was used to produce tubular BNC via cultivations with Acetobacter xylinum, and Kombucha, a symbiosis of acetic acid bacteria and yeasts. The results indicated that Kombucha gave higher yield and productivity of BNC than A. xylinum. Bacterial nanocellulose was simultaneously synthesized both on the inner surface of the outer silicone tube and on the outer surface of the inner silicone tube. Finally, the nano BNC fibrils from two directions formed a BNC tube with good structural integrity. Scanning electron microscopy inspection showed that the tubular BNC had a multilayer structure in the beginning but finally it disappeared and an intact BNC tube formed. The mechanical properties of BNC tubes were comparable with the reported value in literatures, demonstrating a great potential in vascular implants or in functional substitutes in biomedicine.

  5. Preliminary Study on Biosynthesis of Bacterial Nanocellulose Tubes in a Novel Double-Silicone-Tube Bioreactor for Potential Vascular Prosthesis

    Science.gov (United States)

    Wei, Bin; Chen, Lin

    2015-01-01

    Bacterial nanocellulose (BNC) has demonstrated a tempting prospect for applications in substitute of small blood vessels. However, present technology is inefficient in production and BNC tubes have a layered structure that may bring danger after implanting. Double oxygen-permeable silicone tubes in different diameters were therefore used as a tube-shape mold and also as oxygenated supports to construct a novel bioreactor for production of the tubular BNC materials. Double cannula technology was used to produce tubular BNC via cultivations with Acetobacter xylinum, and Kombucha, a symbiosis of acetic acid bacteria and yeasts. The results indicated that Kombucha gave higher yield and productivity of BNC than A. xylinum. Bacterial nanocellulose was simultaneously synthesized both on the inner surface of the outer silicone tube and on the outer surface of the inner silicone tube. Finally, the nano BNC fibrils from two directions formed a BNC tube with good structural integrity. Scanning electron microscopy inspection showed that the tubular BNC had a multilayer structure in the beginning but finally it disappeared and an intact BNC tube formed. The mechanical properties of BNC tubes were comparable with the reported value in literatures, demonstrating a great potential in vascular implants or in functional substitutes in biomedicine. PMID:26090420

  6. Description of a double centrifugation tube method for concentrating canine platelets.

    Science.gov (United States)

    Perazzi, Anna; Busetto, Roberto; Martinello, Tiziana; Drigo, Michele; Pasotto, Daniela; Cian, Francesco; Patruno, Marco; Iacopetti, Ilaria

    2013-07-22

    To evaluate the efficiency of platelet-rich plasma preparations by means of a double centrifugation tube method to obtain platelet-rich canine plasma at a concentration at least 4 times higher than the baseline value and a concentration of white blood cells not exceeding twice the reference range. A complete blood count was carried out for each sample and each concentrate. Whole blood samples were collected from 12 clinically healthy dogs (consenting blood donors). Blood was processed by a double centrifugation tube method to obtain platelet concentrates, which were then analyzed by a flow cytometry haematology system for haemogram. Platelet concentration and white blood cell count were determined in all samples. Platelet concentration at least 4 times higher than the baseline value and a white blood cell count not exceeding twice the reference range were obtained respectively in 10 cases out of 12 (83.3%) and 11 cases out of 12 (91.6%). This double centrifugation tube method is a relatively simple and inexpensive method for obtaining platelet-rich canine plasma, potentially available for therapeutic use to improve the healing process.

  7. Light Production in the Double Chooz Photomultiplier Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Calvo, E.; Cerrada, M.; Crespo, J. I.; Gil-Botella, I.; Jimenez, S.; Lopez, M.; Novella, P.; Palomares, C.; Santorelli, R.; Verdugo, A.

    2012-09-13

    In this document we present a study of the phenomenon of light emission (called glowing) in the bases of the Hamamatsu R7081MOD-ASSY photomultiplier tubes (PMTs) used in the Double Chooz experiment. The tests have been carried out at the CIEMAT laboratories over a photomultiplier tube of the same model. We have studied the phenomenon making first a characterization of it, and then focusing on the dependence of the rate and the amount of emitted light versus voltage and temperature. In addition, we have looked for the possible existence of an ultraviolet component in the light which would be harmful for the experiment because it could be able to excite the scintillator liquid. Finally, we propose and test a method to reduce the light emission using a cover on the base of the photomultiplier tube.. (Author)

  8. Evaluation of single and double centrifugation tube methods for concentrating equine platelets.

    Science.gov (United States)

    Argüelles, D; Carmona, J U; Pastor, J; Iborra, A; Viñals, L; Martínez, P; Bach, E; Prades, M

    2006-10-01

    The aim of this study was to evaluate single and double centrifugation tube methods for concentrating equine platelets. Whole blood samples were collected from clinically normal horses and processed by use of single and double centrifugation tube methods to obtain four platelet concentrates (PCs): PC-A, PC-B, PC-C, and PC-D, which were analyzed using a flow cytometry hematology system for hemogram and additional platelet parameters (mean platelet volume, platelet distribution width, mean platelet component concentration, mean platelet component distribution width). Concentrations of transforming growth factor beta 1 (TGF-beta(1)) were determined in all the samples. Platelet concentrations for PC-A, PC-B, PC-C, and PC-D were 45%, 44%, 71%, and 21% higher, respectively, compared to the same values for citrated whole blood samples. TGF-beta(1) concentrations for PC-A, PC-B, PC-C, and PC-D were 38%, 44%, 44%, and 37% higher, respectively, compared to citrated whole blood sample values. In conclusion, the single and double centrifugation tube methods are reliable methods for concentrating equine platelets and for obtaining potentially therapeutic TGF-beta(1) levels.

  9. Study on drop pressure and flow distribution of double-tube heat exchanger

    International Nuclear Information System (INIS)

    Liu Junqiang; Chen Minghui; Hu Yumin; Li Rizhu; Kong Dechun; Zhang Weijie

    2007-01-01

    The parallel connection channel pressure drop characters of the double-tube bundle heat exchange were experimentally investigated in this paper in order to find out how the flow of the heat exchanger is distributed and then to optimize the structure of heat exchanger according to the flow distribution. A double-tube bundle heat exchanger was built according to the similarity criteria. The experiment system was also built to test the optimization of the heat exchanger. The experiment results reveal that the calculating model is reliable and decreasing pipe space to optimize the heat exchanger is reasonable. (authors)

  10. 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)

  11. 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.

  12. 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%

  13. Parametric study and performance analysis of hybrid rocket motors with double-tube configuration

    Science.gov (United States)

    Yu, Nanjia; Zhao, Bo; Lorente, Arnau Pons; Wang, Jue

    2017-03-01

    The practical implementation of hybrid rocket motors has historically been hampered by the slow regression rate of the solid fuel. In recent years, the research on advanced injector designs has achieved notable results in the enhancement of the regression rate and combustion efficiency of hybrid rockets. Following this path, this work studies a new configuration called double-tube characterized by injecting the gaseous oxidizer through a head end injector and an inner tube with injector holes distributed along the motor longitudinal axis. This design has demonstrated a significant potential for improving the performance of hybrid rockets by means of a better mixing of the species achieved through a customized injection of the oxidizer. Indeed, the CFD analysis of the double-tube configuration has revealed that this design may increase the regression rate over 50% with respect to the same motor with a conventional axial showerhead injector. However, in order to fully exploit the advantages of the double-tube concept, it is necessary to acquire a deeper understanding of the influence of the different design parameters in the overall performance. In this way, a parametric study is carried out taking into account the variation of the oxidizer mass flux rate, the ratio of oxidizer mass flow rate injected through the inner tube to the total oxidizer mass flow rate, and injection angle. The data for the analysis have been gathered from a large series of three-dimensional numerical simulations that considered the changes in the design parameters. The propellant combination adopted consists of gaseous oxygen as oxidizer and high-density polyethylene as solid fuel. Furthermore, the numerical model comprises Navier-Stokes equations, k-ε turbulence model, eddy-dissipation combustion model and solid-fuel pyrolysis, which is computed through user-defined functions. This numerical model was previously validated by analyzing the computational and experimental results obtained for

  14. Peptide signalling during the pollen tube journey and double fertilization.

    Science.gov (United States)

    Qu, Li-Jia; Li, Ling; Lan, Zijun; Dresselhaus, Thomas

    2015-08-01

    Flowering seed plants (angiosperms) have evolved unique ways to protect their gametes from pathogen attack and from drying out. The female gametes (egg and central cell) are deeply embedded in the maternal tissues of the ovule inside the ovary, while the male gametes (sperm cells) are enclosed in the vegetative pollen tube cell. After germination of the pollen tube at the surface of papilla cells of the stigma the two immobile sperm cells are transported deep inside the sporophytic maternal tissues to be released inside the ovule for double fertilization. Angiosperms have evolved a number of hurdles along the pollen tube journey to prevent inbreeding and fertilization by alien sperm cells, and to maximize reproductive success. These pre-zygotic hybridization barriers require intensive communication between the male and female reproductive cells and the necessity to distinguish self from non-self interaction partners. General molecules such as nitric oxide (NO) or gamma-aminobutyric acid (GABA) therefore appear to play only a minor role in these species-specific communication events. The past 20 years have shown that highly polymorphic peptides play a leading role in all communication steps along the pollen tube pathway and fertilization. Here we review our current understanding of the role of peptides during reproduction with a focus on peptide signalling during self-incompatibility, pollen tube growth and guidance as well as sperm reception and gamete activation. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  15. Double plasma arc in a graphite tube - application of discharge atmospheres

    International Nuclear Information System (INIS)

    Arens, C.; Nickel, H.; Mazurkiewicz, M.; Vukanovic, D.

    1981-01-01

    With a view to safety and economic efficiency element-specific limits are required for permissible impurities in reactor graphite. This leads to the necessity of developing suitable methods of analysis. Emission spectroscopy has proved to be a method of analysis featuring a high detection capability and offering the possibility of determining several elements simultaneously. A prolongation of the particle residence time in the plasma (and, thus, an increase in radiation intensity) was the objective when developing a novel spectrochemical source of excitation. The method uses two d.c. arcs burning in a horizontally arranged graphite tube. The double plasma arc in a graphite tube has proved to be an excellent source of excitation for the analysis of powder and solutions. (orig./IHOE)

  16. [Successful double-lumen endotracheal tube exchange with a soft-tipped extra firm exchange catheter in a patient with severe subcutaneous emphysema].

    Science.gov (United States)

    Okamoto, Kaori; Komasawa, Nobuyasu; Ishio, Junichi; Nakano, Shoko; Tatsumi, Shinichi; Minami, Toshiaki

    2014-07-01

    We report a case of successful double-lumen endotracheal tube exchange with a soft-tipped extra firm exchange catheter in a patient with severe subcutaneous emphysema. A 70-year-old man underwent right lower lobectomy for primary lung cancer under general anesthesia. He developed pneumothorax on postoperative day (POD) 14, which led to subcutaneous emphysema. An emergent operation was performed on POD20 to close the pulmonary fistula under general anesthesia with a single-lumen endotracheal tube and bronchial blocker. Subcutaneous emphysema became worse and pharyngeal emphysema was also suspected; re-operation to close the pulmonary or bronchial fistula was planned. We decided to place a double-lumen tube to precisely detect the fistula. Under the guide of a Pentax-AWS Airwayscope, the single-lumen endotracheal tube was exchanged uneventfully to a 35 Fr double-lumen endotracheal tube with a 110 cm soft-tipped extra firm exchange catheter. The fistula was detected by a leak test and the operation was performed uneventfully, leading to improvement of subcutaneous emphysema.

  17. Effectiveness-NTU analyses in a double tube heat exchanger equipped with wavy strip considering various angles

    International Nuclear Information System (INIS)

    Pourahmad, Saman; Pesteei, S.M.

    2016-01-01

    Highlights: • Double tube heat exchanger equipped with wavy strip turbulators was studied. • The effects of wavy strip angles on the effectiveness were investigated. • Variation of the effectiveness with hot and cold water flow rate was presented. • The effectiveness increases with the decrease of wavy strip angle. • The friction factor increases with the decrease of wavy strip angle. - Abstract: In the present study, effectiveness-NTU analyses in a double tube heat exchanger equipped with wavy strip considering various angles were experimentally studied. Moreover, variation of the effectiveness with hot water Reynolds numbers for different cold water flow rates were presented. These turbulators with different angles of 45°, 60°, 90°, 120° and 150° were made of galvanized plates with thickness of 1 mm and were installed in the inner tube of heat exchanger. The experiments were carried out at Reynolds numbers of 3000–13,500 at turbulent flow regime. Throughout the experiments, hot and cold water flowed through the inner pipe and the space between the pipes (annulus), respectively. It was tried to keep the inlet hot and cold water temperatures at constant values. Effectiveness-NTU analyses were made for the conditions with and without wavy strips including their different angles and compared to each other. Results showed the considerable effect of turbulators on effectiveness (ε) and number of heat transfer units (NTU) of double tube heat exchanger. In addition, some empirical correlations expressing the results were also developed based on curve fitting.

  18. Description of a double centrifugation tube method for concentrating canine platelets

    OpenAIRE

    Perazzi, Anna; Busetto, Roberto; Martinello, Tiziana; Drigo, Michele; Pasotto, Daniela; Cian, Francesco; Patruno, Marco; Iacopetti, Ilaria

    2013-01-01

    Background To evaluate the efficiency of platelet-rich plasma preparations by means of a double centrifugation tube method to obtain platelet-rich canine plasma at a concentration at least 4 times higher than the baseline value and a concentration of white blood cells not exceeding twice the reference range. A complete blood count was carried out for each sample and each concentrate. Whole blood samples were collected from 12 clinically healthy dogs (consenting blood donors). Blood was proces...

  19. Male-female crosstalk during pollen germination, tube growth and guidance, and double fertilization.

    Science.gov (United States)

    Dresselhaus, Thomas; Franklin-Tong, Noni

    2013-07-01

    Sperm cells of flowering plants are non-motile and thus require transportation to the egg apparatus via the pollen tube to execute double fertilization. During its journey, the pollen tube interacts with various sporophytic cell types that support its growth and guide it towards the surface of the ovule. The final steps of tube guidance and sperm delivery are controlled by the cells of the female gametophyte. During fertilization, cell-cell communication events take place to achieve and maximize reproductive success. Additional layers of crosstalk exist, including self-recognition and specialized processes to prevent self-fertilization and consequent inbreeding. In this review, we focus on intercellular communication between the pollen grain/pollen tube including the sperm cells with the various sporophytic maternal tissues and the cells of the female gametophyte. Polymorphic-secreted peptides and small proteins, especially those belonging to various subclasses of small cysteine-rich proteins (CRPs), reactive oxygen species (ROS)/NO signaling, and the second messenger Ca(2+), play center stage in most of these processes.

  20. Bronchial lumen is the safer route for an airway exchange catheter in double-lumen tube replacement: preventable complication in airway management for thoracic surgery.

    Science.gov (United States)

    Wu, Hsiang-Ling; Tai, Ying-Hsuan; Wei, Ling-Fang; Cheng, Hung-Wei; Ho, Chiu-Ming

    2017-10-01

    There is no current consensus on which lumen an airway exchange catheter (AEC) should be passed through in double-lumen endotracheal tube (DLT) to exchange for a single-lumen endotracheal tube (SLT) after thoracic surgery. We report an unusual case to provide possible solution on this issue. A 71-year-old man with lung adenocarcinoma had an event of a broken exchange catheter used during a DLT replacement with a SLT, after a video-assisted thoracic surgery. The exchange catheter was impinged at the distal tracheal lumen and snapped during manipulation. All three segments of the catheter were retrieved without further airway compromises. Placement of airway tube exchanger into the tracheal lumen of double-lumen tube is a potential contributing factor of the unusual complication. We suggest an exchange catheter be inserted into the bronchial lumen in optimal depth with the adjunct of video laryngoscope, as the safe method for double-lumen tube exchange.

  1. 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)

  2. Pflicht zur Prüfung der Existenz des Internen Kontrollsystems: Bestandesaufnahme zur Steuerung und Kontrolle mittelgrosser Unternehmen in der Schweiz

    OpenAIRE

    Ruud, T F; Isufi, S; Friebe, P

    2008-01-01

    Die Pflicht zur Prüfung der Existenz des internen Kontrollsystems betrifft auch etliche mittelgrosse Unternehmen. Im Rahmen einer Umfrage haben das Institut für Rechnungswesen und Controlling der Universität Zürich und PricewaterhouseCoopers bei diesen Unternehmen eine Bestandesaufnahme zu Kontroll- und Prüfungsaktivitäten durchgeführt. Nachstehend werden die Ergebnisse der Umfrage zum internen Kontrollsystem präsentiert.

  3. Performance improvements of the BNC tubes from unique double-silicone-tube bioreactors by introducing chitosan and heparin for application as small-diameter artificial blood vessels.

    Science.gov (United States)

    Li, Xue; Tang, Jingyu; Bao, Luhan; Chen, Lin; Hong, Feng F

    2017-12-15

    In order to improve property of bacterial nano-cellulose (BNC) to achieve the requirements of clinical application as small caliber vascular grafts, chitosan (CH) was deposited into the fibril network of the BNC tubes fabricated in unique Double-Silicone-Tube bioreactors. Heparin (Hep) was then chemically grafted into the BNC-based tubes using EDC/NHS crosslinking to improve performance of anticoagulation and endothelialization. Physicochemical and mechanical property, blood compatibility, and cytocompatibility were compared before and after compositing. The results indicated that strength at break was increased but burst pressure decreased slightly after compositing. Performance of the BNC tubes was improved remarkably after introducing chitosan and heparin. The EDC/NHS crosslinking catalyzed both amide bonds and ester bonds formation in the BNC/CH-Hep composites. Three-dimensional surface structure and roughness were firstly obtained and discussed in relation to the hemocompatibility of BNC-based tubes. This work demonstrates the heparinized BNC-based tubes have great potential in application as small-diameter vascular prosthesis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Entropy Generation of Shell and Double Concentric Tubes Heat Exchanger

    Directory of Open Access Journals (Sweden)

    basma abbas abdulmajeed

    2016-06-01

    Full Text Available Entropy generation was studied for new type of heat exchanger (shell and double concentric tubes heat exchanger. Parameters of hot oil flow rate, temperature of inlet hot oil and pressure drop were investigated with the concept of entropy generation. The results showed that the value of entropy generation increased with increasing the flow rate of hot oil and when cold water flow rate was doubled from 20 to 40 l/min, these values were larger. On the other hand, entropy generation increased with increasing the hot oil inlet temperature at a certain flow rate of hot oil. Furthermore, at a certain hot oil inlet temperature, the entropy generation increased with the pressure drop at different hot oil inlet flow rates. Finally, in order to keep up with modern technology, infrared thermography camera was used in order to measure the temperatures. The entropy generation was determined with lower values when infrared thermography camera was used to measure the temperatures, compared with the values obtained by using thermocouples.

  5. Shell and Double Concentric Tube Heat Exchanger Calculations and Analysis

    Directory of Open Access Journals (Sweden)

    Basma Abbas Abdulmajeed

    2015-01-01

    Full Text Available This study concerns a new type of heat exchangers, which is that of shell-and-double concentric tube heat exchangers. The case studies include both design calculations and performance calculations. The new heat exchanger design was conducted according to Kern method. The volumetric flow rates were 3.6 m3/h and 7.63 m3/h for the hot oil and water respectively. The experimental parameters studied were: temperature, flow rate of hot oil, flow rate of cold water and pressure drop. A comparison was made for the theoretical and experimental results and it was found that the percentage error for the hot oil outlet temperature was (- 1.6%. The percentage errors for the pressure drop in the shell and in the concentric tubes were (17.2% and (- 39% respectively. For cold water outlet temperature, the percentage error was (- 3.3%, while it was (18% considering the pressure drop in the annulus formed. The percentage error for the total power consumed was (-10.8% A theoretical comparison was made between the new design and the conventional heat exchanger from the point of view of, length, mass, pressure drop and total power consumed.

  6. Study on the structure optimization scheme design of a double-tube once-through steam

    International Nuclear Information System (INIS)

    Wei, Xinyu; Wu, Shifa; Wang, Pengfei; Zhao, Fuyu

    2016-01-01

    A double-tube once-through steam generator (DOTSG) consisting of an outer straight tube and an inner helical tube is studied in this work. First, the structure of the DOTSG is optimized by considering two different objective functions. The tube length and the total pressure drop are considered as the first and second objective functions, respectively. Because the DOTSG is divided into the subcooled, boiling, and superheated sections according to the different secondary fluid states, the pitches in the three sections are defined as the optimization variables. A multi-objective optimization model is established and solved by particle swarm optimization. The optimization pitch is small in the subcooled region and superheated region, and large in the boiling region. Considering the availability of the optimum structure at power levels below 100% full power, we propose a new operating scheme that can fix the boundaries between the three heat-transfer sections. The operation scheme is proposed on the basis of data for full power, and the operation parameters are calculated at low power level. The primary inlet and outlet temperatures, as well as flow rate and secondary outlet temperature are changed according to the operation procedure

  7. Study on the structure optimization scheme design of a double-tube once-through steam

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Xinyu; Wu, Shifa; Wang, Pengfei; Zhao, Fuyu [Dept. of Nuclear Science and Technology, Xi' an Jiaotong University, Xi' an (China)

    2016-08-15

    A double-tube once-through steam generator (DOTSG) consisting of an outer straight tube and an inner helical tube is studied in this work. First, the structure of the DOTSG is optimized by considering two different objective functions. The tube length and the total pressure drop are considered as the first and second objective functions, respectively. Because the DOTSG is divided into the subcooled, boiling, and superheated sections according to the different secondary fluid states, the pitches in the three sections are defined as the optimization variables. A multi-objective optimization model is established and solved by particle swarm optimization. The optimization pitch is small in the subcooled region and superheated region, and large in the boiling region. Considering the availability of the optimum structure at power levels below 100% full power, we propose a new operating scheme that can fix the boundaries between the three heat-transfer sections. The operation scheme is proposed on the basis of data for full power, and the operation parameters are calculated at low power level. The primary inlet and outlet temperatures, as well as flow rate and secondary outlet temperature are changed according to the operation procedure.

  8. Multi-objective shape optimization of double pipe heat exchanger with inner corrugated tube using RSM method

    International Nuclear Information System (INIS)

    Han, Huai-Zhi; Li, Bing-Xi; Wu, Hao; Shao, Wei

    2015-01-01

    Integrated a fully developing three-dimensional heat transfer and flow model, a multi-objective optimization aims to fulfill the geometric design for double-tube heat exchangers with inner corrugated tube is investigated in this work with RSM. Dimensionless corrugation pitch (p/D), dimensionless corrugation height (H/D), dimensionless corrugation radius (r/D) and Reynolds number (Re) are considered as four design parameters. Considering the process parameters, the characteristic numbers involving heat transfer characteristic, resistance characteristic and overall heat transfer performance calculated by CFD, and are served as objective functions to the RSM (Nu c , f c , Nu c /Nu s , f c /f s and h in this paper). The results of optimal designs are a set of multiple optimum solutions, called 'Pareto optimal solutions'. It reveals the identical tendency of Nu c /Nu s and f c /f s reflecting the conflict between them that means augmenting the heat transfer performance with various design parameters in the optimal situation inevitably sacrificed the increase of flow resistance. According to the Pareto optimal curves, the optimum designing parameters of double pipe heat exchanger with inner corrugated tube under the constrains of Nu c /Nu s ≥1.2 are found to be P/D = 0.82, H/D = 0.22, r/D = 0.23, Re = 26,263, corresponding to the maximum value of η = 1.12. (authors)

  9. Structural Pre-sizing of a Coaxial Double-tube Type Hot Gas Duct

    Energy Technology Data Exchange (ETDEWEB)

    Song, Kee Nam; Kim, Y-W [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2008-10-15

    The nuclear hydrogen system being researched at KAERI is planning to produce hydrogen in the order of 950 .deg. C by using nuclear energy and a thermo-chemical process, and helium gas is tentatively considered as the choice for the coolant. A hot gas duct (HGD) is a key component connecting the reactor pressure vessel and the intermediate heat exchanger (IHX) for the nuclear hydrogen system. The HGD is a unique component exclusively found in an HTR-module concept where a nuclear core and IHX are placed separately into two pressure vessels, which require a connecting duct between them. A coaxial double-tube type cross vessel is considered for the HGD structure of the nuclear hydrogen system because of its successive extensive experience. In this study, a structural pre-sizing for the primary HGD was carried out. These activities include a predecision on the geometric dimensions, a pre-evaluation on the strength, and a pre-selection on the material of the coaxial double-tube type cross vessel components. A predecision on the geometric dimensions was undertaken based on various engineering concepts, such as a constant flow velocity (CFV) model, a constant flow rate (CFR) model, a constant hydraulic head (CHH) model, and finally a heat balanced (HB) model. For the CFV model, CFR model, and CHH model, the HGD structure might be insensitive to a flow induced vibration (FIV) in the case where there are no pressure differences between the hot and cold helium regions. Also we compared the geometric dimensions from the various models.

  10. A Study of Free-Piston Double-Diaphragm Drivers for Expansion Tubes. Report 1

    Science.gov (United States)

    Kendall, M. A.

    1997-01-01

    In recent years the free-piston double-diaphragm driver has been used to increase the performance of the XI pilot expansion tube to super-orbital test conditions. However, the actual performance of the double-diaphragm driver was found to be considerably less than ideal. An experimental study of the double-diaphragm driver was carried out on the XI facility over a range of conditions with the objective of determining the effect of. heat losses; and the non-ideal rupture of the 'light' secondary diaphragm on the driver performance. The disparity between the theoretical and measured performance envelope are highlighted. A viscous limit for the experiments vas established. Heat transfer behind the primary shock is shown to be the mechanism behind this limit Incident, reflected and transmitted shock trajectories for the secondary diaphragm were experimentally determined and compared with computed trajectories from a one-dimensional diaphragm inertia model. It was found that the diaphragm did influence the unsteady expansion. A good agreement between experimental and computed shock trajectories was obtained using a diaphragm inertia model assuming that the diaphragm mass became negligible 3 microns after shock impact.

  11. Pyeloplasty for hydronephrosis: Issues of double J stent versus nephrostomy tube as drainage technique

    Directory of Open Access Journals (Sweden)

    Ravi Kumar Garg

    2015-01-01

    Full Text Available Aims: To compare the efficacy, complications, cost analysis and hospital stay between two methods of drainage of the kidney: double J (DJ stent versus nephrostomy tube following open pyeloplasty for ureteropelvic junction obstruction hydronephrosis. Patients and Methods: This was a prospective randomized study of 20 patients in each group over 14 months. Pre and post-operative (3 months function and drainage were assessed by ethylenedicysteine scan and intravenous urogram. Results: Both groups showed similar good improvement in function and drainage. Nephrostomy group had significantly longer hospital stay (P < 0.001 but incurred less cost. Complications with nephrostomy included tube breakage (n = 1 and urine leak after tube removal (n = 2. DJ stents were associated with stent migration (n = 4, increased frequency of micturition (n = 9, dysuria (n = 4 and urinary tract infection (n = 1. Conclusion: Both methods of drainage did not interfere with improvement after pyeloplasty. Minor complications were more with DJ stent (P = 0.0003. Although overall cost of treatment was more with stents, they reduced length of hospital stay. Optimal length of stent is essential to reduce complications secondary to migration and bladder irritation.

  12. The Mashups of YouTube

    DEFF Research Database (Denmark)

    Simonsen, Thomas Mosebo

    2013-01-01

    This article focuses on YouTube mashups and how we can understand them as a specific subgenre on YouTube. The Mashups are analysed as audiovisual recontextualizations that are given new meaning, e.g., via collaborative social communities or for individual promotional purposes. This is elaborated......, but rather in its social and communicative abilities within the YouTube community. This leads to the article’s overall argument that the main characteristic of the YouTube Mashup can be explained in terms of connectivity. It is argued that Mashups reveal a double articulation of connectivity; one...... that involves the social mechanisms of the Mashups, and another mode, which concerns the explicit embedding of structural connectivity that accentuates the medium-specific infrastructure of YouTube. This double articulation of connectivity is furthermore elaborated on by including Grusin and Bolter’s concept...

  13. Double tube heat exchanger with novel enhancement: Part I - flow development length and adiabatic friction factor

    Energy Technology Data Exchange (ETDEWEB)

    Tiruselvam, R.; Raghavan, Vijay R. [Universiti Teknologi PETRONAS, Faculty of Mechanical Engineering, Tronoh (Malaysia)

    2012-04-15

    The study is conducted to evaluate the flow characteristics in a double tube heat exchanger using two new and versatile enhancement configurations. The novelty is that they are usable in single phase forced convection, evaporation and condensation. Correlations are proposed for flow development length and friction factor for use in predicting fluid pumping power in thermal equipment as well as in subsequent heat transfer characterization of the surface. (orig.)

  14. Technology of double casing tubes & a binary cycle system for hole cleaning for CBM multi-branch horizontal wells

    Directory of Open Access Journals (Sweden)

    Yong Yang

    2017-03-01

    Full Text Available At present, the aeration-assisted cutting-carrying technology is faced with complexities in the drilling of CBM multi-branch horizontal wells. For example, the aerating pressure is hardly maintained, and the borehole instability may happen. In view of these prominent problems, the technology of double casing tubes & a binary cycle system suitable for CBM multi-branch horizontal wells was developed according to the Venturi principle by means of parasitic tube insufflation which is used for well control simulation system. Then, a multiphase flow finite element model was established for the fluid-cutting particle system in this drilling condition. This technology was tested in field. Double-casing tubes cementing is adopted in this technology and a jet generator is installed at the bottom of the inner casing. In the process of drilling, the drilling fluid injected through double intermediate casing annulus is converted by the jet generator into a high-efficiency steering water jet, which, together with the water jet generated by the bit nozzle, increases the fluid returning rate in the inner annulus space. It is indicated from simulation results that the cutting-carrying effect is the best when the included angle between the nozzle of the jet generator and the vertical direction is 30°. Besides, the influential laws of cutting size, primary cycle volume, accessory cycle volume and drilling velocity on hole cleaning are figured out. It is concluded that this technology increases the flow rate of drilling fluid in annulus space, the returning rate of drilling fluid significantly and the cutting-carrying capacity. It is currently one of the effective hole cleaning technologies for CBM multi-branch horizontal wells where fresh water is taken as the drilling fluid.

  15. Analogue saturation limit of single and double 10 mm microchannel plate photomultiplier tubes

    Energy Technology Data Exchange (ETDEWEB)

    Milnes, J. S., E-mail: james.milnes@photek.co.uk; Conneely, T. M. [Photek Ltd., 26 Castleham Road, St Leonards on Sea, East Sussex TN38 9NS (United Kingdom); Horsfield, C. J. [AWE Aldermaston, Reading, Berkshire RG7 4PR (United Kingdom)

    2016-11-15

    Photek are a well-established supplier of microchannel plate (MCP) photomultiplier tubes (PMTs) to the inertial confinement fusion community. The analogue signals produced at the major inertial confinement fusion facilities cover many orders of magnitude, therefore understanding the upper saturation limit of MCP-PMTs to large low rate signals takes on a high importance. Here we present a study of a single and a double MCP-PMT with 10 mm diameter active area. The saturation was studied for a range of optical pulse widths from 4 ns to 100 ns and at a range of electron gain values: 10{sup 3} to 10{sup 4} for the single and 10{sup 4} to 10{sup 6} for the double. We have shown that the saturation level of ∼1.2 nC depends only on the integrated charge of the pulse and is independent of pulse width and gain over this range, but that the level of charge available in deep saturation is proportional to the operating gain.

  16. Petrology and geochemistry of VLT glasses from double drive tube 79001/2

    Science.gov (United States)

    Wentworth, Susan J.; Lindstrom, D. J.; Martinez, R. R.; Mckay, D. S.

    1993-01-01

    As a part of more general studies of soils from Apollo 17 double drive tube 79001/2, glasses from the 79001/2 core are being analyzed by a multidisciplinary approach including SEM/EDS and INAA. Efforts are currently focused on VLT (very low-Ti; TiO2 less than 1 wt%) mare glasses, which are common in 79001/2 and have also been found in other Apollo 17 soils. One of the primary objectives is to determine whether any or all of the Apollo 17 VLT glasses represent pristine volcanic compositions. In addition, the range of VLT glass compositions and possible relationships between the glasses and VLT lithic samples, for which some geochemical data have been obtained previously, is being defined.

  17. Validierung der Wirksamkeitsprüfung für Clostridium tetani Impfstoffe ad usum veterinarium durch den direkten Nachweis von Tetanus-Antitoxin im Zieltier mittels ELISA

    OpenAIRE

    Roßkopf, Ute

    2007-01-01

    Die dargelegten Ergebnisse zur Validierung einer neuen Wirksamkeitsprüfung von Tetanus-Impfstoffen resultieren aus umfangreichen Feldstudien, durchgeführt mit neun unterschiedlichen Impfstoffen für das Pferd sowie acht Impfstoffen für das Schaf. Insgesamt wurden 102 Pferde und 82 Schafe entsprechend den Angaben in der Gebrauchsinformation immunisiert. Blutentnahmen fanden nach einem vorgegebenen Schema von bis zu zwei Jahren nach der ersten Impfung statt. Die Impfstoffe waren entweder monoval...

  18. A study on the FIV characteristics of a coaxial double-tube under counter flow

    Energy Technology Data Exchange (ETDEWEB)

    Song, K. N.; Kim, Y. W. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, S. C. [ABLEMAX, Seoul (Korea, Republic of)

    2009-07-01

    A VHTR of 200 MWt that produces heat at temperatures in the order of 950 .deg. C is being considered for the nuclear hydrogen system at KAERI. A structural pre-sizing for the coaxial double-tube type cross vessel was carried out to modulate a Flow-Induced Vibration (FIV) and a Fluid-Structure Interaction (FSI) analysis has been carried our using the ADINA code. When compared the FIV characteristics of the proposed design cases by an FSI interaction, and it was found that maximum displacements of the HGD structure are mainly affected by the flow velocity rather than the structural stiffness.

  19. 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

  20. CFD simulation and experimental validation of a GM type double inlet pulse tube refrigerator

    Science.gov (United States)

    Banjare, Y. P.; Sahoo, R. K.; Sarangi, S. K.

    2010-04-01

    Pulse tube refrigerator has the advantages of long life and low vibration over the conventional cryocoolers, such as GM and stirling coolers because of the absence of moving parts in low temperature. This paper performs a three-dimensional computational fluid dynamic (CFD) simulation of a GM type double inlet pulse tube refrigerator (DIPTR) vertically aligned, operating under a variety of thermal boundary conditions. A commercial computational fluid dynamics (CFD) software package, Fluent 6.1 is used to model the oscillating flow inside a pulse tube refrigerator. The simulation represents fully coupled systems operating in steady-periodic mode. The externally imposed boundary conditions are sinusoidal pressure inlet by user defined function at one end of the tube and constant temperature or heat flux boundaries at the external walls of the cold-end heat exchangers. The experimental method to evaluate the optimum parameters of DIPTR is difficult. On the other hand, developing a computer code for CFD analysis is equally complex. The objectives of the present investigations are to ascertain the suitability of CFD based commercial package, Fluent for study of energy and fluid flow in DIPTR and to validate the CFD simulation results with available experimental data. The general results, such as the cool down behaviours of the system, phase relation between mass flow rate and pressure at cold end, the temperature profile along the wall of the cooler and refrigeration load are presented for different boundary conditions of the system. The results confirm that CFD based Fluent simulations are capable of elucidating complex periodic processes in DIPTR. The results also show that there is an excellent agreement between CFD simulation results and experimental results.

  1. Experimental study and modelisation of a pulse tube refrigerator

    International Nuclear Information System (INIS)

    Ravex, A.; Rolland, P.; Liang, J.

    1992-01-01

    A test bench for pulse tube refrigerator characterization has been built. In various configurations (basic pulse tube, orifice pulse tube and double inlet pulse tube), the ultimate temperature and the cooling power have been measured as a function of pressure wave amplitude and frequency for various geometries. A lowest temperature of 28 K has been achieved in a single staged double inlet configuration. A modelisation taking into account wall heat pumping, enthalpy flow and regenerator inefficiency is under development. Preliminary calculation results are compared with experimental data

  2. "Detachment of the carinal hook following endobronchial intubation with a double lumen tube"

    Directory of Open Access Journals (Sweden)

    Rocha Ana C

    2011-10-01

    Full Text Available Abstract Background Carinal hooks increases difficulty at endotracheal intubation. Amputation of the carinal hook during passage and malpositioning of the tube to the hook are some of the potential problems related with left-sided Carlens double lumen tube (DLT. This article reports an amputation of the hook during a difficult selective intubation and aimed at calling the attention to complications associated with DLTs and the importance of fiberoptic bronchoscopy. Case presentation A 68 year-old woman was scheduled for right-sided thoracotomy in whom blind DLT insertion was performed. Narrowed trachea causes difficulty in rotating the DLT 90° counter-clockwise. After carinal hook was noticed upon visual inspection of the DLT, fiberoptic bronchoscopy was used to remove the missing part (with the use of forceps from the right mainstem bronchus. Conclusion Insertion of DLTs with carinal hook is associated with technical problems and potentially life-threatening hazards have discouraged their use. Fiberoptic evaluation and repositioning solves most of the problems. Although amputation of the carinal hook has not been previously reported, clinicians should be alert. This case report emphasizes the utility of the fiberoptic bronchoscopy in the operating theatre for placement, positioning and inspection of the carinal hook DLT.

  3. New model of universal gas-filled neutron tube

    International Nuclear Information System (INIS)

    Bespalov, D.F.; Bessarabskii, I.G.; Voitsik, L.R.; Mints, A.Z.

    1985-01-01

    The UNG-1 gas-filled neutron tube is serially produced. In type UNG neutron generators, the tube operates in the pulsed mode in the high voltage doubling circuit arrangement. During extended operation, its advantages were discovered: long operating time, fairly stable neutron yield, and simplicity of use and operation. However, the mean neutron yield (approx.10 7 s -1 ) generated by the tube in the optimal mode at the present time proved to be inadequate in solving numerous geophysical problems. So a model of a neutron tube, model UNG-2, was designed, ensuring an enhanced neutron yield of 10 8 s -1 in the continuous-operating mode. When the tube is connected to the high voltage doubling circuit, the mean neutron yield is only somewhat in excess of the neutron yield from the UNG-1 tube

  4. Computed Tomographic Window Setting for Bronchial Measurement to Guide Double-Lumen Tube Size.

    Science.gov (United States)

    Seo, Jeong-Hwa; Bae, Jinyoung; Paik, Hyesun; Koo, Chang-Hoon; Bahk, Jae-Hyon

    2018-04-01

    The bronchial diameter measured on computed tomography (CT) can be used to guide double-lumen tube (DLT) sizes objectively. The bronchus is known to be measured most accurately in the so-called bronchial CT window. The authors investigated whether using the bronchial window results in the selection of more appropriately sized DLTs than using the other windows. CT image analysis and prospective randomized study. Tertiary hospital. Adults receiving left-sided DLTs. The authors simulated selection of DLT sizes based on the left bronchial diameters measured in the lung (width 1,500 Hounsfield unit [HU] and level -700 HU), bronchial (1,000 HU and -450 HU), and mediastinal (400 HU and 25 HU) CT windows. Furthermore, patients were randomly assigned to undergo imaging with either the bronchial or mediastinal window to guide DLT sizes. Using the underwater seal technique, the authors assessed whether the DLT was appropriately sized, undersized, or oversized for the patient. On 130 CT images, the bronchial diameter (9.9 ± 1.2 mm v 10.5 ± 1.3 mm v 11.7 ± 1.3 mm) and the selected DLT size were different in the lung, bronchial, and mediastinal windows, respectively (p study, oversized tubes were chosen less frequently in the bronchial window than in the mediastinal window (6/110 v 23/111; risk ratio 0.38; 95% CI 0.19-0.79; p = 0.003). No tubes were undersized after measurements in these two windows. The bronchial measurement in the bronchial window guided more appropriately sized DLTs compared with the lung or mediastinal windows. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Enhancement of heat transfer rate with structural modification of double pipe heat exchanger by changing cylindrical form of tubes into conical form

    International Nuclear Information System (INIS)

    Hashemian, Mehran; Jafarmadar, Samad; Nasiri, Javid; Sadighi Dizaji, Hamed

    2017-01-01

    Highlights: • An improved geometry is presented by changing tubes form into conical. • Enhancement of heat transfer rate is investigated. • Frictional characteristics for novel geometry are studied. • For a proper understanding of the subject, the exact physical interpretation is added. • The effect of flow, geometry and thermodynamic parameters is considered. - Abstract: In this paper, cylindrical tubes of a double pipe heat exchanger were changed into the conical tubes as an innovative design which causes improvement of thermal performance of heat exchanger without increment of its weight. Utilization of conical tube instead of cylindrical tube can impress both thermal and frictional characteristics of heat exchanger. Hence, the effect of conical tubes on Nusselt number, friction factor and thermal performance factor are evaluated in present research which was not covered already. Moreover, the effects of hydrodynamic, thermodynamic and geometrical characteristics are analyzed. All said parameters are numerically investigated for nine different combinations of flow direction and conical tubes geometry. The results of simulations of the said configurations are presented to compare the cases from different points of view and determine the most thermally efficient case. The results reveal modified geometry makes 63% increment in Nu number and 54% increment in heat transfer rate at optimum condition.

  6. 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)

  7. Full-scale measurements and system identification on Sutong cable-stayed bridge during Typhoon Fung-Wong.

    Science.gov (United States)

    Wang, Hao; Tao, Tianyou; Guo, Tong; Li, Jian; Li, Aiqun

    2014-01-01

    The structural health monitoring system (SHMS) provides an effective tool to conduct full-scale measurements on existing bridges for essential research on bridge wind engineering. In July 2008, Typhoon Fung-Wong lashed China and hit Sutong cable-stayed bridge (SCB) in China. During typhoon period, full-scale measurements were conducted to record the wind data and the structural vibration responses were collected by the SHMS installed on SCB. Based on the statistical method and the spectral analysis technique, the measured data are analyzed to obtain the typical parameters and characteristics. Furthermore, this paper analyzed the measured structural vibration responses and indicated the vibration characteristics of the stay cable and the deck, the relationship between structural vibrations and wind speed, the comparison of upstream and downstream cable vibrations, the effectiveness of cable dampers, and so forth. Considering the significance of damping ratio in vibration mitigation, the modal damping ratios of the SCB are identified based on the Hilbert-Huang transform (HHT) combined with the random decrement technique (RDT). The analysis results can be used to validate the current dynamic characteristic analysis methods, buffeting calculation methods, and wind tunnel test results of the long-span cable-stayed bridges.

  8. Full-Scale Measurements and System Identification on Sutong Cable-Stayed Bridge during Typhoon Fung-Wong

    Directory of Open Access Journals (Sweden)

    Hao Wang

    2014-01-01

    Full Text Available The structural health monitoring system (SHMS provides an effective tool to conduct full-scale measurements on existing bridges for essential research on bridge wind engineering. In July 2008, Typhoon Fung-Wong lashed China and hit Sutong cable-stayed bridge (SCB in China. During typhoon period, full-scale measurements were conducted to record the wind data and the structural vibration responses were collected by the SHMS installed on SCB. Based on the statistical method and the spectral analysis technique, the measured data are analyzed to obtain the typical parameters and characteristics. Furthermore, this paper analyzed the measured structural vibration responses and indicated the vibration characteristics of the stay cable and the deck, the relationship between structural vibrations and wind speed, the comparison of upstream and downstream cable vibrations, the effectiveness of cable dampers, and so forth. Considering the significance of damping ratio in vibration mitigation, the modal damping ratios of the SCB are identified based on the Hilbert-Huang transform (HHT combined with the random decrement technique (RDT. The analysis results can be used to validate the current dynamic characteristic analysis methods, buffeting calculation methods, and wind tunnel test results of the long-span cable-stayed bridges.

  9. Observation of double loop insertion of silicone rubber tube anastomosis method combined with "Z" flap repair in the treatment of lacrimal ductule laceration

    Directory of Open Access Journals (Sweden)

    Rui Hou

    2017-03-01

    Full Text Available AIM: To investigate the clinical curative effect of double loop insertion of silicone rubber tube combined with "Z" flap repair in the treatment of laceration of eyelid with canaliculus laceration. METHODS: The paper reviewed 45 cases of laceration of eyelid with laceration canaliculus, caused by trauma, which were treated in my hospital from January 2014 to January 2016. In the process of anastomosis of lacrimal duct and suture of eyelid laceration, either the method of single spinal anesthesia tube placement on skin contraposition suture or the method of dual annular silicone tube placement combined with the word "Z" flap repair was used. We compared the two methods and studied the possible complications like eyelid varus and valgus, lacrimal point valgus, eyelid scar, anastomotic dehiscence again. RESULTS: Out of the 22 cases in which the patients chose the single spinal anesthesia tube implantation on skin suture, 21 cases succeeded and patients received lacrimal duct patency results after extubation; and 1 case anastomosis failed. Complications: 20 cases had different degree of complications and the impact on their appearances were significant. Out of the 23 cases in which the patients chose double passage annular silicone tube joint prosthesis implantation Z flap, 23 received extubation results lacrimal patency or almost patency, the anastomosis of patients was successful. Complications: in two cases, patients had mild eyelid entropion and pomatum varus. Both eyelid deformity and severe wound tear did not occur in all cases again. Scar was not obvious. The success rate of anastomosis between the two groups was not significantly different(P=0.4889. To compare the rate of complications, there were significant differences(χ2=30.42, PCONCLUSION: The application of dual ring implantation silicon tube combined with the word "Z" flap repair in the treatment of lacrimal canaliculi laceration of eyelid laceration ensured the success rate of

  10. Tensile strength of Zr-2.5 Nb pressure tubes: A statistical study

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Priti Kotak, E-mail: pritik@barc.gov.in [Senior Scientist, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Dubey, J.S.; Datta, D.; Shriwastaw, R.S.; Rath, B.N.; Singh, R.N. [Senior Scientist, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Anantharaman, S. [Head, Post Irradiation Examination Division, Bhabha Atomic Research Centre, Mumbai (India); Chakravartty, J.K. [Director, Materials Group, Bhabha Atomic Research Centre, Mumbai (India)

    2015-12-15

    Highlights: • Tensile properties in axial and transverse direction for a number of Indian Zr-2.5 Nb PHWR pressure tubes. • Distribution of tensile properties of double-melted and quadruple-melted pressure tubes. • Tensile properties at front-end and back-end of the quadruple melted pressure tubes at room temperature and at 300 °C. - Abstract: In order to get an idea of the statistical variation in the tensile properties of the double-melted as well as quadruple melted Zr-2.5 Nb pressure tubes (PTs) and also the variation in tensile properties between the two ends of the pressure tubes, tension tests were carried out on around 50 pressure tube off-cuts. Longitudinal and transverse tensile specimens were prepared from these off-cuts of pressure tubes of double-melted and quadruple melted types. For quadruple melted pressure tubes the specimens were tested from both front-end and back-end off-cuts. Miniature flat tensile specimens having 1.8 mm width and 1.5 mm thickness and 7.6 mm gauge length were prepared from the pressure tube off-cuts without any flattening treatment. Tension tests were carried out in a screw-driven machine at room temperature and 300 °C for both front-end and back-end off-cuts of each of 16 pressure tubes. In general the transverse specimens showed higher yield strength (YS) and ultimate tensile strength (UTS) compared to the longitudinal specimens. Transverse specimens showed less strain hardening compared to the longitudinal specimens. The axial specimens showed higher uniform (UE) and total elongation (TE) compared to the transverse specimens. Double-melted pressure tubes showed relatively higher strength and lower elongation and larger standard deviation compared to the quadruple melted pressure tubes. Mean values of tensile properties showed that back-end off-cuts were relatively stronger and less ductile compared to the front-end off-cuts.

  11. Multi objective optimization of foam-filled circular tubes for quasi-static and dynamic responses

    Directory of Open Access Journals (Sweden)

    Fauzan Djamaluddin

    Full Text Available AbstractFuel consumption and safety are currently key aspects in automobile design. The foam-filled thin-walled aluminium tube represents a potentially effective material for use in the automotive industry, due to its energy absorption capability and light weight. Multi-objective crashworthiness design optimization for foam-filled double cylindrical tubes is presented in this paper. The double structures are impacted by a rigid wall simulating quasi-static and dynamic loadings. The optimal parameters under consideration are the minimum peak crushing force and maximum specific energy absorption, using the non-dominated sorting genetic algorithm-II (NSGA-II technique. Radial basis functions (RBF and D-Optimal are adopted to determine the more complex crashworthiness functional objectives. The comparison is performed by finite element analysis of the impact crashworthiness characteristics in tubes under static and dynamic loads. Finally, the optimum crashworthiness performance of empty and foam-filled double tubes is investigated and compared to the traditional single foam-filled tube. The results indicate that the foam-filled double aluminium circular tube can be recommended for crashworthy structures.

  12. High-fidelity simulation of lung isolation with double-lumen endotracheal tubes and bronchial blockers in anesthesiology resident training.

    Science.gov (United States)

    Failor, Erin; Bowdle, Andrew; Jelacic, Srdjan; Togashi, Kei

    2014-08-01

    Demonstrate the feasibility of using the AirSim Bronchi airway simulator to teach residents how to manage lung isolation with double-lumen endotracheal tubes and bronchial blockers and evaluate their performance with a detailed checklist. Prospective observational study. University anesthesiology residency training program. Anesthesiology residents taking a cardiothoracic anesthesiology rotation. Residents were instructed in 7 tasks using the AirSim Bronchi: The use of the fiberoptic bronchoscope, methods for placing left and right double-lumen endotracheal tubes and 3 bronchial blockers (Univent, Arndt, and Cohen), and application of continuous positive airway pressure (CPAP) to the unventilated lung. Two to 3 weeks later, checklists and a detailed scoring system were used to assess performance. Residents rated the curriculum and their own confidence in performing the tasks using a 5-point Likert scale. Thirteen residents completed the curriculum. Their median Likert scale ratings of the curriculum based on a questionnaire with 6 items ranged from 4 to 5 of 5. Resident confidence scores for each lung isolation technique improved after the simulation training, with the median gain ranging from 0.5 to 1.5 Likert levels depending on the task. The largest improvement occurred with the bronchial blockers (psimulator in a novel simulation curriculum to teach lung-isolation techniques to anesthesiology residents and evaluated performance using a detailed checklist scoring system. This curriculum is a promising educational tool. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Passive heat transfer enhancement in 3D corrugated tube

    DEFF Research Database (Denmark)

    Navickaité, Kristina; Engelbrecht, Kurt; Bahl, Christian

    transfer and fluid flow with a constant wall temperature and total pressure drop. The governing equations for these problems were solved using the Finite Element Method. The results of numerical modelling show significant increase in NTU for double corrugated tubes compared to a circular tube. The friction......An innovative hydraulic design was studied for corrugated tube geometry for a heat exchanger. An ellipse based double corrugation was used as a concept of the geometry. The hydraulic diameter (Dh) is maintained over the tube length while the shape of the cross section varies continuously along...... the flow direction. 38 corrugated tubes with a Dh of 5 mm were studied numerically with corrugation heights from 0.23 to 0.69 mm and corrugation periods from 5 to 50 mm for laminar flow with water. Computational fluid dynamics (CFD) is used as a tool to study the effect of corrugation geometry on heat...

  14. Intrathoracic esophageal replacement in the dog with the use of an artificial esophagus composed of a collagen sponge with a double-layered silicone tube.

    Science.gov (United States)

    Yamamoto, Y; Nakamura, T; Shimizu, Y; Matsumoto, K; Takimoto, Y; Kiyotani, T; Sekine, T; Ueda, H; Liu, Y; Tamura, N

    1999-08-01

    Intrathoracic esophageal replacement with an artificial esophagus is considered difficult. We attempted to replace the intrathoracic esophagus with an artificial esophagus composed of a collagen sponge with a double-layered silicone tube and examined the state of host tissue regeneration. A 5-cm long gap was created in the intrathoracic esophagus in 9 dogs and repaired by interposition of our prosthesis. The dogs were fed only by intravenous hyperalimentation for 28 days. The silicone tube was removed at 29 days after the operation, and oral feeding was reintroduced. One dog was put to death at each of the following times: 1, 2, 3, 3, 6, 12, and 24 months after the operation. One dog is still surviving without problems after more than 26 months. One dog died of malnutrition at 10 months. In all dogs, the host regenerated tissue had replaced the resulting gap at the time of silicone tube removal. The mucosa had fully regenerated within 3 months and the glands within 12 months. The process of stenosis and shrinkage was complete within 3 months and did not advance thereafter. The lamina muscularis mucosae were observed as islets of smooth muscle within 12 months. Although the skeletal muscle regenerated close to the anastomoses, it did not extend to the middle of the regenerated esophagus even after 24 months. Use of a collagen sponge with a double-layered silicone tube was shown to be feasible even in the thorax and to allow the regenerated host tissue, consisting of the mucosa, glands, and lamina muscularis mucosae, to replace the esophageal gap.

  15. Combination of intravenous dexmedetomidine with topicalization of airway for placement of double lumen tube in a spontaneously breathing patient of giant lung bullae

    Directory of Open Access Journals (Sweden)

    Vikas Karne

    2016-10-01

    Here we present a patient with giant lung bulla in left lower lobe with severely reduced pulmonary reserves and significant air-trapping posted for VAT assisted bullectomy. Anaesthesia challenges including pathological changes, its effects during induction of anaesthesia, and issues related to placement of double lumen tube in a spontaneously breathing patient are discussed with possible advantages of dexmedetomidine in this special group of patients.

  16. Streak tube development

    International Nuclear Information System (INIS)

    Hinrichs, C.K.; Estrella, R.M.

    1979-01-01

    A research program for the development of a high-speed, high-resolution streak image tube is described. This is one task in the development of a streak camera system with digital electronic readout, whose primary application is for diagnostics in underground nuclear testing. This program is concerned with the development of a high-resolution streak image tube compatible with x-ray input and electronic digital output. The tube must be capable of time resolution down to 100 psec and spatial resolution to provide greater than 1000 resolution elements across the cathode (much greater than presently available). Another objective is to develop the capability to make design changes in tube configurations to meet different experimental requirements. A demountable prototype streak tube was constructed, mounted on an optical bench, and placed in a vacuum system. Initial measurements of the tube resolution with an undeflected image show a resolution of 32 line pairs per millimeter over a cathode diameter of one inch, which is consistent with the predictions of the computer simulations. With the initial set of unoptmized deflection plates, the resolution pattern appeared to remain unchanged for static deflections of +- 1/2-inch, a total streak length of one inch, also consistent with the computer simulations. A passively mode-locked frequency-doubled dye laser is being developed as an ultraviolet pulsed light source to measure dynamic tube resolution during streaking. A sweep circuit to provide the deflection voltage in the prototype tube has been designed and constructed and provides a relatively linear ramp voltage with ramp durations adjustable between 10 and 1000 nsec

  17. Optimization of the Darrieus wind turbines with double-multiple-streamtube model

    International Nuclear Information System (INIS)

    Paraschivoiu, I.

    1985-01-01

    This paper discusses a new improvement of the double-multiple-stream tube model by considering the stream tube expansion effects on the Darrieus wind turbine. These effects, allowing a more realistic modeling of the upwind/downwind flow field asymmetries inherent in the Darrieus rotor, were calculated by using CARDAAX computer code. When the dynamic stall is introduced in the double-multiple-stream tube model, the aerodynamic loads and performance show significant changes in the range of low tip-speed ratio

  18. Finite Element Analysis and Crashworthiness Optimization of Foam-filled Double Circular under Oblique Loading

    Directory of Open Access Journals (Sweden)

    Fauzan Djamaluddin

    Full Text Available Abstract Finite element analysis and optimization design carry out for the quasi static responses of foam-filled double circular tube is presented in this paper. In the investigation of the crashworthiness capability, some aspects were considered for variations in geometry parameters of tubes and the loading condition to investigate the crashworthiness capability. Empty, foam-filled, and full foam-filled doublé tubes of thin walled structures were observed subjected to oblique impact (0˚ - 40˚. The numerical solution was used to determine the crashworthiness parameters. In addition, NSGA II and Radial Basis Function were used to optimize the crashworthiness capability of tubes. In conclution, the crash performaces of foam-filled double tube is better than the other structures in this work. The outcome that expected is the new design information of various kinds of cylindrical tubes for energy absorber application.

  19. A study on LMFBR steam generator design without tube failure propagation in water leak events

    International Nuclear Information System (INIS)

    Futagami, Satoshi; Hayafune, Hiroki; Fujimura, Ken; Sato, Mitsuru

    2009-01-01

    The major target performance of the SG for commercialized FBR is not only economic performance but also property protection performance. The candidate SG design will be selected at the end of JFY 2010. The straight double wall tube SG is one of the SG candidates for commercialized FBR, and other SG concepts were studied in this paper. In proposing an alternative SG, alternative technological measures with a double wall tube were investigated and included reinforcing the tube against wastage and quick detection of initial tube leaks. Alternative SG concept candidates for preventing tube failure propagation and mitigation of water leak accidents were proposed through a combination of technological measures. The candidates were then comparatively evaluated from the point of view of property protection performance, total weight, technological issues, and so on. A coated wall tube SG and protective wall tube SG were decided on as the alternative SGs because of superior property protection performance and with the technological issues. At the end of JFY 2010, the straight double wall tube SG will be decided upon as the result of R and D activities, and alternative SGs evaluated in feasibility studies. A plan for studying feasibility with the technological issues of the alternative SG was proposed. (author)

  20. Status of pulse tube development at CEA/SBT

    International Nuclear Information System (INIS)

    Ravex, A.; Rolland, P.

    1994-01-01

    Interest in the pulse tube comes from its potential for high reliability and low level of induced vibration. A numerical model has been developed to provide a tool for practical design. It has been successfully validated against the experimental results obtained with a single stage double inlet pulse tube which has achieved a temperature of 28 K at a frequency of a few Hz. Further developments have demonstrated the capability of operating a pulse tube at higher frequencies in association with a Stirling pressure oscillator. Current projects include coaxial geometry for miniature pulse tubes with linear resonant pressure oscillators. A 4 K multistaged pulse tube is also in development. (authors). 5 figs., 12 refs

  1. Role of intertube interactions in double- and triple-walled carbon nanotubes.

    Science.gov (United States)

    Hirschmann, Thomas Ch; Araujo, Paulo T; Muramatsu, Hiroyuki; Rodriguez-Nieva, Joaquin F; Seifert, Max; Nielsch, Kornelius; Kim, Yoong Ahm; Dresselhaus, Mildred S

    2014-02-25

    Resonant Raman spectroscopy studies are performed to access information about the intertube interactions and wall-to-wall distances in double- and triple-walled carbon nanotubes. Here, we explain how the surroundings of the nanotubes in a multiwalled system influence their radial breathing modes. Of particular interest, the innermost tubes in double- and triple-walled carbon nanotube systems are shown to be significantly shielded from environmental interactions, except for those coming from the intertube interaction with their own respective host tubes. From a comparison of the Raman results for bundled as well as individual fullerene-peapod-derived double- and triple-walled carbon nanotubes, we observe that metallic innermost tubes, when compared to their semiconducting counterparts, clearly show weaker intertube interactions. Additionally, we discuss a correlation between the wall-to-wall distances and the frequency upshifts of the radial breathing modes observed for the innermost tubes in individual double- and triple-walled carbon nanotubes. All results allow us to contemplate fundamental properties related to DWNTs and TWNTs, as for example diameter- and chirality-dependent intertube interactions. We also discuss differences in fullerene-peapod-derived and chemical vapor deposition grown double- and triple-walled systems with the focus on mechanical coupling and interference effects.

  2. Advanced evacuated tube collectors

    Science.gov (United States)

    Schertz, W. W.; Hull, J. R.; Winston, R.; Ogallagher, J.

    1985-04-01

    The essence of the design concept for these new collectors is the integration of moderate levels of nonimaging concentration inside the evacuated tube itself. This permanently protects the reflection surfaces and allows the use of highly reflecting front surface mirrors with reflectances greater than 95%. Previous fabrication and long term testing of a proof-of-concept prototype has established the technical success of the concept. Present work is directed toward the development of a manufacturable unit that will be suitable for the widest possible range of applications. Design alternatives include scaling up the original prototype's tube diameter from 5 cm to 10 cm, using an internal shaped metal concentrating reflector, using a variety of profile shapes to minimize so-called gap losses and accommodate both single ended and double-ended flow geometries, and allowing the use of heat pipes for the absorber tube.

  3. Studying the effect of the shape parameters on the performance of the darrieus wind turbine using the multiple double disk stream tube theory

    International Nuclear Information System (INIS)

    Elmabrok, Ali Mohamed; Al-makhlufi, Ahmed A.

    2006-01-01

    The performance of the Darrieus vertical axis turbine is comparable with that of the more common horizontal axis machines. It has a number of aerodynamic and structural advantages over HAWTS. However the darrieus turbines are not self-starting at low wind speeds which is a considerable disadvantage for a simple small scale installation. Generally, papers concerning vertical axis turbine do not study the behavior of the rotor at low tip speed ratios. Therefore they do not deal with the self starting problems. A number of analytical methods were investigated to see whether they could predict the starting performance of vertical axis turbines. The chosen methods and 'actuator disc theory' for multiple stream tubes. In this paper the multiple stream tube model is applied using two discs in tandem. The computational analysis of all models simulates the blade aerodynamics throughout the full range of incidence from 180 degree centigrade. The effects of varying various geometric parameters of the windmill upon the performance of the rotor are investigated to find a design with improved self starting characteristics. The best agreement between theory and experiment was obtained using the multiple stream tube (double disc) models.(Author)

  4. A simple coated-tube assay for alpha-foeto protein for clinical use

    International Nuclear Information System (INIS)

    Dakubu, S.; Ahene, I.S.; Foli, A.K.

    1977-01-01

    A standard method for coating plastic tubes with antiserum has been applied to coat tubes with rabbit antiserum to human alpha-foeto protein. The coated plastic tubes have been used to set up a radioimmunoassay system which is sensitive and convenient for use on the occasional clinical sample. For a successful coated-tube assay, it was found necessary to modify the final incubation mixture from what was suitable in a standard double antibody assay system. (orig.) [de

  5. Double-layer ion acceleration triggered by ion magnetization in expanding radiofrequency plasma sources

    International Nuclear Information System (INIS)

    Takahashi, Kazunori; Charles, Christine; Boswell, Rod W.; Fujiwara, Tamiya

    2010-01-01

    Ion energy distribution functions downstream of the source exit in magnetically expanding low-pressure plasmas are experimentally investigated for four source tube diameters ranging from about 5 to 15 cm. The magnetic-field threshold corresponding to a transition from a simple expanding plasma to a double layer-containing plasma is observed to increase with a decrease in the source tube diameter. The results demonstrate that for the four geometries, the double layer and the accelerated ion beam form when the ion Larmour radius in the source becomes smaller than the source tube radius, i.e., when the ions become magnetized in the source tube.

  6. Double-lumen tubes and auto-PEEP during one-lung ventilation.

    Science.gov (United States)

    Spaeth, J; Ott, M; Karzai, W; Grimm, A; Wirth, S; Schumann, S; Loop, T

    2016-01-01

    Double-lumen tubes (DLT) are routinely used to enable one-lung-ventilation (OLV) during thoracic anaesthesia. The flow-dependent resistance of the DLT's bronchial limb may be high as a result of its narrow inner diameter and length, and thus potentially contribute to an unintended increase in positive end-expiratory pressure (auto-PEEP). We therefore studied the impact of adult sized DLTs on the dynamic auto-PEEP during OLV. In this prospective clinical study, dynamic auto-PEEP was determined in 72 patients undergoing thoracic surgery, with right- and left-sided DLTs of various sizes. During OLV, air trapping was provoked by increasing inspiration to expiration ratio from 1:2 to 2:1 (five steps). Based on measured flow rate, airway pressure (Paw) and bronchial pressure (Pbronch), the pressure gradient across the DLT (ΔPDLT) and the total auto-PEEP in the respiratory system (i.e. the lungs, the DLT and the ventilator circuit) were determined. Subsequently the DLT's share in total auto-PEEP was calculated. ΔPDLT was 2.3 (0.7) cm H2O over the entire breathing cycle. At the shortest expiratory time the mean total auto-PEEP was 2.9 (1.5) cm H2O (range 0-5.9 cm H2O). The DLT caused 27 to 31% of the total auto-PEEP. Size and side of the DLT's bronchial limb did not impact auto-PEEP significantly. Although the DLT contributes to the overall auto-PEEP, its contribution is small and independent of size and side of the DLT's bronchial limb. The choice of DLT does not influence the risk of auto-PEEP during OLV to a clinically relevant extent. DRKS00005648. © The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. Point-of-care ultrasound versus auscultation in determining the position of double-lumen tube.

    Science.gov (United States)

    Hu, Wei-Cai; Xu, Lei; Zhang, Quan; Wei, Li; Zhang, Wei

    2018-03-01

    This study was designed to assess the accuracy of point-of-care ultrasound in determining the position of double-lumen tubes (DLTs).A total of 103 patients who required DLT intubation were enrolled into the study. After DLTs were tracheal intubated in the supine position, an auscultation researcher and ultrasound researcher were sequentially invited in the operating room to conduct their evaluation of the DLT. After the end of their evaluation, fiberscope researchers (FRs) were invited in the operating room to evaluate the position of DLT using a fiberscope. After the patients were changed to the lateral position, the same evaluation process was repeated. These 3 researchers were blind to each other when they made their conclusions. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were obtained by statistical analysis.When left DLTs (LDLTs) were used, the accuracy of ultrasound (84.2% [72.1%, 92.5%]) was higher than the accuracy of auscultation (59.7% [45.8%, 72.4%]) (P auscultation (67.4% [52.0%, 80.5%]) (P auscultation (54.4% [40.7%, 67.6%]) (P auscultation (47.8% [32.9%, 63.1%]) (P auscultation in determining the position of DLTs.

  8. Micose fungóide: estudo epidemiológico de 17 casos e avaliação da resposta terapêutica à PUVA Mycosis fungoides: epidemiologic study of 17 cases and evaluation of PUVA photochemotherapy

    Directory of Open Access Journals (Sweden)

    Ida Duarte

    2006-02-01

    Full Text Available FUNDAMENTOS: A fotoquimioterapia com PUVA é indicada para tratamento da micose fungóide, empregada como monoterapia em estágios precoces ou combinada a outras drogas nos estágios mais avançados da doença. OBJETIVOS: Avaliação da resposta terapêutica à fotoquimioterapia PUVA em pacientes com micose fungóide. MÉTODOS: Entre janeiro de 1996 e novembro de 2003 avaliaram-se 17 pacientes com micose fungóide no setor de Fototerapia da Clínica Dermatológica da Santa Casa de São Paulo. A terapia com PUVA foi realizada como monoterapia nos estádios iniciais ou como coadjuvante nos estádios avançados da doença. Avaliou-se o resultado do tratamento quanto ao aspecto clínico das lesões e parâmetros histológicos após tratamento. RESULTADOS: Quatorze de 16 pacientes responderam à fotoquimioterapia. Relacionando o estadiamento da doença à resposta terapêutica obteve-se o seguinte: cinco pacientes (um em estágio IA e quatro em IB com controle total (cura das lesões; quatro (todos IB com melhora intensa (controle de 70-99%; dois (IIB e IVA com melhora moderada (de 50 a 69%; três (IA, IB, IIA com melhora discreta (menos 50%; dois (IB, IIB inalterados (sem resposta. Um paciente teve de descontinuar o tratamento por apresentar intenso ardor. CONCLUSÃO: Houve resposta à terapia PUVA em 87% dos pacientes, com controle total ou melhora intensa da doença em 56% dos casos. Sua efetividade permitiu regressão das lesões cutâneas, principalmente nos casos precoces. A fotoquimioterapia com PUVA mostrou ser tratamento seguro e efetivo, devendo ser considerado em pacientes com micose fungóide.BACKGROUND: PUVA photochemotherapy is indicated to treat mycosis fungoides, either as monotherapy in the earlier stages of the disease or in combination with other drugs in more advanced stages of evolution. OBJECTIVES: To evaluate PUVA photochemotherapy response in patients with mycosis fungoides. METHODS: From January 1996 to November 2003, 17

  9. Crush analysis of the foam-filled bitubal circular tube under oblique impact

    Science.gov (United States)

    Djamaluddin, F.; Abdullah, S.; Arrifin, A. K.; Nopiah, Z. M.

    2018-02-01

    This paper presents crashworthiness analysis of bitubal cylindrical tubes under different impact angular. The numerical solution of double cylindrical tubes are determined by finite element analysis (FEA). Moreover, the structure was impacted by mass block as impactor respect to longitudinal direction of the tubes. The model of structure was developed by non-linear ABAQUS sofware with variations of load angle and dimensions of tube. The outcome of this study is the respons parameters such as the peak crusing force (PCF), energy absorption (EA) and specific energy absorption (SEA), thus it can be expected this tube as the great energy absorber.

  10. The Maui International Double Star Conference

    Science.gov (United States)

    Genet, Russell

    2013-04-01

    A three-day double star conference in February, 2013, covered double star observations from simple eyepiece astrometry of wide binaries, with orbital periods of centuries, to amplitude interferometry of binaries with periods measured in days or even hours. A wide range of participants, from students and amateurs to professionals shared their perspectives in panel discussions. This was the first conference of the newly-formed International Association of Double Star Observers (IADSO). PDFs of 22 of the talks and YouTube links to 23 of the talks and panels are available at www.IADSO.org.

  11. Experimental Study of Flow Boiling Heat Transfer in a Horizontal Microfin Tube

    OpenAIRE

    Yu, Jian; Koyama, Shigeru; Momoki, Satoru

    1995-01-01

    An experimental study on flow boiling heat transfer in a horizontal microfin tube is conducted with pure refrigerants HFC134a, HCFC123 and HCFC22 using a water-heated double-tube type test section. The test microfin tube is a copper tube having the following dimensions: 8.37mm mean inside diameter, 0.168mm fin height, 60fin number and 18 degree of helix angle. The local heat transfer coefficients for both counter and parallel flows are measured in a range of heat flux of 1 to 93W/m^2, mass ve...

  12. Indication chamber of liquid metal fired steam generators with double wall for heat transfer

    International Nuclear Information System (INIS)

    Matal, O.; Martoch, J.

    1982-01-01

    The double wall of the steam generator consists of inner and outer tubes anchored in a tube plate. Between the tubes are indication spaces which end in recesses formed at least in one of the tube plates and coaxial with the outer tubes. The recesses interconnected with channels form the indication chamber to which is connected at least one sensor of the alarm signal equipment. (B.S.)

  13. Writing Gardens - Gardening Drawings: Fung, Brunier and Garening as a model of Landscape Architectural Practice

    Directory of Open Access Journals (Sweden)

    Julian Raxworthy

    2004-06-01

    Full Text Available Landscape architecture is different from other design discourses, notably architecture, because of its utilisation of' dynamic' construction media such as plant materials, soils and water, compared with the 'static' materials of architecture, colloquially described as bricks and mortar. This dynamism refers to the fact that landscape materials not only change, but get better over time. While this is a material difference, its implications extend to practice, which has been modelled, from architecture, to favour a static mode of representation: the drawing. While the drawing is important for the propositional nature of landscape architecture, it may be valuable to look at other disciplines, allied to landscape architecture, which might be seen as better able to engage with change. In this essay, the garden provides just such an example. In the writings of Stanislaus Fung on the Chinese garden text the Yuan vi, an argument is made about writing being a fundamental act in the endeavour of gardening that may offer a bridge across the 'ontological disparity' that exists between representation and the subject, the landscape. To speak of writing in this context suggests that writing about gardens is actually a type of gardening in itself. This argument is extended in the current essay quickly to see if it is also appropriate to consider drawings in this way. This essay also attempts to legitimate theoretically the real possibility of modifying landscape architectural practices to engage with change, by suggesting what might be learned from gardening. In further research by this author, this argument will be used as the theoretical basis for critiquing gardens in such a way that lessons learnt from garden designers can be valuably incorporated back into the discourse of landscape architecture.

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    Here we report the use of x-ray tube based irradiators as alternatives to gamma sources for laboratory scale irradiation. Irradiators were designed with sample placement in closest possible proximity to the source, allowing high dose rates for small samples. Designs using 1000 W x-ray tubes in single tube, double tube, and four tube configurations are described, as well as various cabinet construction techniques. Relatively high dose rates were achieved for small samples, demonstrating feasibility for laboratory based irradiators for research purposes. Dose rates of 9.76, 5.45, and 1.7 Gy/min/tube were measured at the center of a 12.7 cm container of instant rice at 100 keV, 70 keV, and 40 keV, respectively. Dose uniformity varies dramatically as the distance from source to container. For 2.54 cm diameter sample containers containing adult Navel Orangeworm, dose rates of 50–60 Gy/min were measured in the four tube system. - Highlights: • X-ray is demonstrated as an alternative to gamma for lab-based irradiation. • Cabinets using one, two, and four 1000 W tubes are reported. • Dose rate of 9.8 Gy/min/tube at the center of a 12.7 cm container of instant rice. • Dose uniformity varies dramatically as the distance from source to container.

  15. Overlapping double potential wells in a single optical microtube cavity with vernier-scale-like tuning effect

    International Nuclear Information System (INIS)

    Madani, A.; Schmidt, O. G.; Bolaños Quiñones, V. A.; Ma, L. B.; Jorgensen, M. R.; Miao, S. D.

    2016-01-01

    Spatially and temporally overlapping double potential wells are realized in a hybrid optical microtube cavity due to the coexistence of an aggregate of luminescent quantum dots embedded in the tube wall and the cone-shaped tube's geometry. The double potential wells produce two independent sets of optical modes with different sets of mode numbers, indicating phase velocity separation for the modes overlapping at the same frequency. The overlapping mode position can be tuned by modifying the tube cavity, where these mode sets shift with different magnitudes, allowing for a vernier-scale-like tuning effect.

  16. Primary carcinoma of the Fallopian tubes

    International Nuclear Information System (INIS)

    Escalona Veloz, Rafael; Lopez Rodriguez, Caridad; Nunnez Quintana, Adrian; Rizo Reve, Rafael

    2010-01-01

    The clinical case of a 53 year old patient with history of vaginal bleeding for possible uterine fibroma is described. A total hysterectomy with double ooferectomia was performed. The complementary tests results, including the biopsy, confirmed the presence of a primary carcinoma of the right Fallopian tube. A radiotherapy and follow up were indicated in 'Conrado Benitez' Oncology Hospital from Santiago de Cuba

  17. 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.

  18. Irradiation stratigraphy and depositional history of the Apollo 16 double drive tube 60009/10

    Science.gov (United States)

    Blanford, G. E.; Blanford, J.; Hawkins, J. A.

    1979-01-01

    We report track density frequency distributions, the fraction of high density grains and minimum track densities for 63, 1 mm wide locations in the Apollo 16 double drive tube 60009/10. From these data we conclude that there are seven irradiation strata in the core. Only one buried reworking zone extending from 50-52 cm was found and it was exposed near the surface from 4.5-9 times 10 to the 6th y with a most probable exposure period of 6 times 10 to the 6th y. There is lack of conclusive data that this zone represents a reworking zone in which case the material below 52 cm most probably was exposed in situ for 4.5 times 10 to the 6th y and developed a reworking zone approximately less than 0.5 cm. The present surface of the core has a reworking zone of 12-13 cm which was exposed from 1.3 times 10 to the 7th to 2.5 times 10 to the 8th y. The best estimate for this exposure period remains the value of approximately less than 1.25 times 10 to the 8th y determined by Bogard and Hirsch (1976). The other strata in the core appear to contain mixtures of various soil types and are not related to in situ depositional events.

  19. Characterization of the ETEL D784UKFLB 11 in. photomultiplier tube

    Energy Technology Data Exchange (ETDEWEB)

    Barros, N.; Kaptanoglu, T. [University of Pennsylvania, Philadelphia, PA 19104 (United States); Kimelman, B. [Muhlenberg College, Allentown, PA 18104 (United States); Klein, J.R. [University of Pennsylvania, Philadelphia, PA 19104 (United States); Moore, E.; Nguyen, J. [University of California, Davis, Davis, CA 95616 (United States); Stavreva, K. [University of Pennsylvania, Philadelphia, PA 19104 (United States); Svoboda, R., E-mail: rsvoboda@physics.ucdavis.edu [University of California, Davis, Davis, CA 95616 (United States)

    2017-04-21

    Water Cherenkov and scintillator detectors are a critical tool for neutrino physics. Their large size, low threshold, and low operational cost make them excellent detectors for long baseline neutrino oscillations, proton decay, supernova and solar neutrinos, double beta decay, and ultra-high energy astrophysical neutrinos. Proposals for a new generation of large detectors rely on the availability of large format, fast, cost-effective photomultiplier tubes. The Electron Tubes Enterprises, Ltd (ETEL) D784KFLB 11 in. Photomultiplier Tube has been developed for large neutrino detectors. We have measured the timing characteristics, relative efficiency, and magnetic field sensitivity of the first fifteen prototypes.

  20. Track chambers based on precision drift tubes housed inside 30 mm mylar pipe

    International Nuclear Information System (INIS)

    Borisov, A; Bozhko, N; Fakhrutdinov, R; Kozhin, A; Leontiev, B; Levin, A

    2014-01-01

    We describe drift chambers consisting of 3 layers of 30 mm (OD) drift tubes made of double sided aluminized mylar film with thickness 0.125 mm. A single drift tube is self-supported structure withstanding 350 g tension of 50 microns sense wire located in the tube center with 10 microns precision with respect to end-plug outer surface. Such tubes allow to create drift chambers with small amount of material, construction of such chambers doesn't require hard frames. Twenty six chambers with working area from 0.8 × 1.0 to 2.5 × 2.0 m 2 including 4440 tubes have been manufactured for experiments at 70-GeV proton accelerator at IHEP(Protvino)

  1. Track chambers based on precision drift tubes housed inside 30 mm mylar pipe

    Science.gov (United States)

    Borisov, A.; Bozhko, N.; Fakhrutdinov, R.; Kozhin, A.; Leontiev, B.; Levin, A.

    2014-06-01

    We describe drift chambers consisting of 3 layers of 30 mm (OD) drift tubes made of double sided aluminized mylar film with thickness 0.125 mm. A single drift tube is self-supported structure withstanding 350 g tension of 50 microns sense wire located in the tube center with 10 microns precision with respect to end-plug outer surface. Such tubes allow to create drift chambers with small amount of material, construction of such chambers doesn't require hard frames. Twenty six chambers with working area from 0.8 × 1.0 to 2.5 × 2.0 m2 including 4440 tubes have been manufactured for experiments at 70-GeV proton accelerator at IHEP(Protvino).

  2. Overlapping double potential wells in a single optical microtube cavity with vernier-scale-like tuning effect

    Energy Technology Data Exchange (ETDEWEB)

    Madani, A.; Schmidt, O. G. [Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstr. 20, 01069 Dresden (Germany); Material Systems for Nanoelectronics, Chemnitz University of Technology, Reichenhainer Str. 70, 09107 Chemnitz (Germany); Bolaños Quiñones, V. A.; Ma, L. B., E-mail: l.ma@ifw-dresden.de; Jorgensen, M. R. [Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstr. 20, 01069 Dresden (Germany); Miao, S. D. [Anhui Key Lab of Controllable Chemical Reaction and Material Chemical Engineering, School of Chemical Engineering, Hefei University of Technology, Tunxi Road. 193, Hefei, Anhui 230009 (China)

    2016-04-25

    Spatially and temporally overlapping double potential wells are realized in a hybrid optical microtube cavity due to the coexistence of an aggregate of luminescent quantum dots embedded in the tube wall and the cone-shaped tube's geometry. The double potential wells produce two independent sets of optical modes with different sets of mode numbers, indicating phase velocity separation for the modes overlapping at the same frequency. The overlapping mode position can be tuned by modifying the tube cavity, where these mode sets shift with different magnitudes, allowing for a vernier-scale-like tuning effect.

  3. Thermal effect on transverse vibrations of double-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Zhang, Y Q; Liu, X; Liu, G R

    2007-01-01

    Based on the theory of thermal elasticity mechanics, a double-elastic beam model is developed for transverse vibrations of double-walled carbon nanotubes with large aspect ratios. The thermal effect is incorporated in the formulation. With this double-elastic beam model, explicit expressions are derived for natural frequencies and associated amplitude ratios of the inner to the outer tubes for the case of simply supported double-walled carbon nanotubes. The influence of temperature change on the properties of transverse vibrations is discussed. It is demonstrated that some properties of transverse vibrations of double-walled carbon nanotubes are dependent on the change of temperature

  4. Longitudinally excited CO2 laser with multiple laser tubes

    Science.gov (United States)

    Uno, Kazuyuki; Akitsu, Tetsuya; Jitsuno, Takahisa

    2016-11-01

    We developed a longitudinally excited CO2 laser system that was constituted of two or three laser tubes and a single driving circuit. The multiple laser tubes simultaneously produced almost the same short laser pulses with a spike pulse width of about 164 ns and a pulse tail length of about 74 μs with a single driving circuit. The double-tube system was constituted of two 30 cm-long laser tubes with inner diameters of 13 mm and 16 mm and a single driving circuit with an input energy of 2.18 J. The output energy of the 13 mm-tube was 23.3 mJ, and that of the 16 mm-tube was 21.9 mJ at a gas pressure of 4.2 kPa (CO2:N2:He = 1:1:2). The triple-tube system was constituted of three 30 cm-long laser tubes with inner diameters of 9 mm, 13 mm, and 16 mm and a single driving circuit with an input energy of 2.18 J. The output energy of the 9 mm tube was 15.9 mJ, that of the 13 mm tube was 24.1 mJ, and that of the 16 mm tube was 19.2 mJ at a gas pressure of 4.2 kPa. With the same driving circuit and the same input energy, the total output energies of the multitube laser systems were higher than the output energy of a single-tube system.

  5. Tracking with Straw Tubes in the PANDA Experiment

    Directory of Open Access Journals (Sweden)

    Bragadireanu M.

    2014-03-01

    Full Text Available The PANDA spectrometer will be built at the FAIR facility at Darmstadt (Germany to perform accurate tests of the strong interaction through ¯pp and ¯pA annihilation studies. The charged particle tracking at PANDA will be done using both solid state and gaseous detectors. Among the latter, two straw tube detector systems will be built [1]. The cylindrical, central straw tube tracker features a high spatial and momentum resolution for a wide range of particle momenta from about 8 GeV/c down to a few 100 MeV/c, together with particle identification in the momentum region below about 1 GeV/c by measuring the specific energy-loss. A new technique, based on self-supporting straw double layers with intrinsic wire tension developed for the COSY-TOF straw tracker [2], has been adopted for the PANDA trackers. The development of the readout electronics for the straw tubes is ongoing. Prototypes have been produced and used to instrument straw tube modules that have been tested with cosmic rays and proton beams. Design issues of the PANDA straw tubes, together with the results of the prototype tests are presented.

  6. 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 ...

  7. Porous double-layer polymer tubing for the potential use in heterogeneous continuous flow reactions.

    Science.gov (United States)

    Herwig, Gordon; Hornung, Christian H; Peeters, Gary; Ebdon, Nicholas; Savage, G Paul

    2014-12-24

    Functional polymer tubing with an OD of 1/16 or 1/8 in. was fabricated by a simple polymer coextrusion process. The tubing was made of an outer impervious polypropylene layer and an inner layer, consisting of a blend of a functional polymer, polyethylene-co-methacrylic acid, and a sacrificial polymer, polystyrene. After a simple solvent leaching step using common organic solvents, the polystyrene was removed, leaving behind a porous inner layer that contains functional carboxylic acid groups, which could then be used for the immobilization of target molecules. Solution-phase reactions using amines or isocyanates have proven successful for the immobilization of a series of small molecules and polymers. This flexible multilayered functional tubing can be easily cut to the desired length and connected via standard microfluidic fittings.

  8. The beginning of a seed: regulatory mechanisms of double fertilization.

    Science.gov (United States)

    Bleckmann, Andrea; Alter, Svenja; Dresselhaus, Thomas

    2014-01-01

    THE LAUNCH OF SEED DEVELOPMENT IN FLOWERING PLANTS (ANGIOSPERMS) IS INITIATED BY THE PROCESS OF DOUBLE FERTILIZATION: two male gametes (sperm cells) fuse with two female gametes (egg and central cell) to form the precursor cells of the two major seed components, the embryo and endosperm, respectively. The immobile sperm cells are delivered by the pollen tube toward the ovule harboring the female gametophyte by species-specific pollen tube guidance and attraction mechanisms. After pollen tube burst inside the female gametophyte, the two sperm cells fuse with the egg and central cell initiating seed development. The fertilized central cell forms the endosperm while the fertilized egg cell, the zygote, will form the actual embryo and suspensor. The latter structure connects the embryo with the sporophytic maternal tissues of the developing seed. The underlying mechanisms of double fertilization are tightly regulated to ensure delivery of functional sperm cells and the formation of both, a functional zygote and endosperm. In this review we will discuss the current state of knowledge about the processes of directed pollen tube growth and its communication with the synergid cells resulting in pollen tube burst, the interaction of the four gametes leading to cell fusion and finally discuss mechanisms how flowering plants prevent multiple sperm cell entry (polyspermy) to maximize their reproductive success.

  9. INTER-LAYER INTERACTION IN DOUBLE-WALLED CARBON NANOTUBES EVIDENCED BY SCANNING TUNNELING MICROSCOPY AND SPECTROSCOPY

    DEFF Research Database (Denmark)

    Giusca, Cristina E; Tison, Yann; Silva, S. Ravi P.

    2008-01-01

    and the overall electronic structure for double-walled carbon nanotubes, is demonstrated by our experiments, showing that the effect the inner tube has on the overall electronic structure of double-walled nanotubes cannot be neglected, and is key to the opto-electronic properties of the system. We postulate...... that previous analysis of the opto-electronic properties on multiple-walled carbon nanotubes based purely on the outer layer chirality of the tube needs significant modification based on new understanding brought forth with our analysis....

  10. Predicting the elastic properties of double-walled carbon nanotubes by molecular dynamics simulation

    International Nuclear Information System (INIS)

    Zhang Chenli; Shen Huishen

    2008-01-01

    Molecular dynamics simulation is performed on a double-walled carbon nanotube (DWCNT) to predict its elastic properties based on a double-walled shear deformable shell model. By direct buckling measurement, we present here a method for uniquely determining the effective wall thickness for the shell model. Accounting for two different kinds of DWCNTs by adding an inner or outer tube to a fiducial tube, the mechanical properties of DWCNTs are carefully investigated as compared with those of the fiducial tube. It is found that the predicted values of Young's and shear moduli depend strongly on the construction and helicity of DWCNTs, while the dependence on nanotube length is relatively small. The results also confirm that the temperature variation has a significant effect on the elastic properties of DWCNTs

  11. Did low tube voltage CT combined with low contrast media burden protocols accomplish the goal of "double low" for patients? An overview of applications in vessels and abdominal parenchymal organs over the past 5 years.

    Science.gov (United States)

    Shen, Yaqi; Hu, Xuemei; Zou, Xianlun; Zhu, Di; Li, Zhen; Hu, Daoyu

    2016-09-01

    Imaging communities have already reached a consensus that the radiation dose of computed tomography (CT) should be reduced as much as reasonably achievable to lower population risks. Increasing attention is being paid to iodinated contrast media (CM) induced nephrotoxicity (CIN); a decrease in the intake of iodinated CM is required by increasingly more radiologists. Theoretically, the radiation dose varies with the tube current time and square of the tube voltage, with higher iodine contrast at low photon energies (Huda et al. [2000] Radiology, 21 7, 430-435).The use of low tube voltage is a promising strategy to reduce both the radiation dose and CM burden. The term 'double low' has been coined to describe scanning protocols that reduce radiation dose and iodine intake synchronously. These protocols are becoming increasingly popular in the clinical setting. The aim of this review was to describe all original studies using the 'double low' strategy in the last 5 years. We searched an online electronic database (PubMed) from January 2011 to December 2015 for original studies published on the relationship of low tube voltage with low radiation dose and low iodine contrast media burden in patients undergoing CT scans. Studies that failed to reduce radiation dose or iodine CM burden were excluded in this study. Thirty-seven studies aimed at reducing radiation dose using low tube voltage combined with iodine CM reduced protocols were included in this study. Most studies evaluated conditions associated with arteries. Four were cerebral and neck computed tomography angiography (CTA) studies, 15 were pulmonary CTA (pCTA) and coronary CTA (cCTA) studies, one concerned myocardial perfusion, five studies focused on the thoracic and abdominal aorta, and one investigated renal arteries. Three studies consisted of CT venography (CTV) of the pelvis and lower extremities. Six publications examined the liver, and two focused on the kidney. Overall, this review demonstrates that

  12. Strengthening of a railway bridge with NSMR and CFRP tubes

    DEFF Research Database (Denmark)

    Täljsten, Björn; Bennitz, Anders; Danielsson, Georg

    2008-01-01

    Strengthening of structures with CFRP is today considered an accepted method to upgrade concrete structures. In this paper two different CFRP strengthening systems are combined to give extended service life to a Swedish double-trough-double-track railway bridge, constructed in concrete with a 10 ....... Sensors on bars and tubes display proofs of utilization of the CFRP while displacement sensors and strain gauges on the steel reinforcement due to the small loads in the service limit state show minor effect....

  13. 2D double-layer-tube-shaped structure Bi2S3/ZnS heterojunction with enhanced photocatalytic activities

    International Nuclear Information System (INIS)

    Gao, Xiaoming; Wang, Zihang; Fu, Feng; Li, Xiang; Li, Wenhong

    2015-01-01

    Bi 2 S 3 /ZnS heterojunction with 2D double-layer-tube-shaped structures was prepared by the facile synthesis method. The corresponding relationship was obtained among loaded content to phase, morphology, and optical absorption property of Bi 2 S 3 /ZnS composite. The results shown that Bi 2 S 3 loaded could evidently change the crystallinity of ZnS, enhance the optical absorption ability for visible light of ZnS, and improve the morphologies and microstructure of ZnS. The photocatalytic activities of the Bi 2 S 3 /ZnS sample were evaluated for the photodegradation of phenol and desulfurization of thiophene under visible light irradiation. The results showed that Bi 2 S 3 loaded greatly improved the photocatalytic activity of ZnS, and the content of loaded Bi 2 S 3 had an impact on the catalytic activity of ZnS. Moreover, the mechanism of enhanced photocatalytic activity was also investigated by analysis of relative band positions of Bi 2 S 3 and ZnS, and photo-generated hole was main active radicals during photocatalytic oxidation process

  14. 2D double-layer-tube-shaped structure Bi2S3/ZnS heterojunction with enhanced photocatalytic activities

    Science.gov (United States)

    Gao, Xiaoming; Wang, Zihang; Fu, Feng; Li, Xiang; Li, Wenhong

    2015-10-01

    Bi2S3/ZnS heterojunction with 2D double-layer-tube-shaped structures was prepared by the facile synthesis method. The corresponding relationship was obtained among loaded content to phase, morphology, and optical absorption property of Bi2S3/ZnS composite. The results shown that Bi2S3 loaded could evidently change the crystallinity of ZnS, enhance the optical absorption ability for visible light of ZnS, and improve the morphologies and microstructure of ZnS. The photocatalytic activities of the Bi2S3/ZnS sample were evaluated for the photodegradation of phenol and desulfurization of thiophene under visible light irradiation. The results showed that Bi2S3 loaded greatly improved the photocatalytic activity of ZnS, and the content of loaded Bi2S3 had an impact on the catalytic activity of ZnS. Moreover, the mechanism of enhanced photocatalytic activity was also investigated by analysis of relative band positions of Bi2S3 and ZnS, and photo-generated hole was main active radicals during photocatalytic oxidation process.

  15. Evaluation of neutron streaming in fast breeder reactor fuel assembly by double heterogeneous modelling

    International Nuclear Information System (INIS)

    Unesaki, Hironobu; Takeda, Toshikazu

    1988-01-01

    Neutron streaming in a fast breeder reactor fuel assembly caused by the double heterogeneity structure is estimated by double heterogeneous modelling. The conventional pin cell model, a two-region subassembly model and the exact pin cluster model are used to take into account the streaming effect caused by the pin cell structure and the surrounding wrapper tube structure. The heterogeneity of wrapper tube and its surrounding sodium is explicitly considered. The streaming effect is evaluated based on Benoist's diffusion coefficient. The total streaming effect caused by the double heterogeneity structure of a fuel subassembly is found to be -0.2 % dk/kk' for k eff , which is almost twice that obtained from the conventional pin cell model of -0.1 % dk/kk'. (author)

  16. Geochemistry of HASP, VLT, and other glasses from double drive tube 79001/2

    Science.gov (United States)

    Lindstrom, D. J.; Wentworth, S. J.; Martinez, R. R.; Mckay, D. S.

    1992-01-01

    The Apollo 17 double drive tube 79001/2 (station 9, Van Serg Crater) is distinctive because of its extreme maturity, abundance, and variety of glass clasts. It contains mare glasses of both high Ti and very low Ti (VLT) compositions, and highland glasses of all compositions common in lunar regolith samples: highland basalt (feldspathic; Al2O3 greater than 23 wt percent), KREEP (Al2O3 less than 23 wt percent, K2O greater than 0.25 wt percent), and low-K Fra Mauro (LKFM; Al2O3 less than 23 wt percent, K2O less than 0.25 wt percent). It also contains rare specimens of high-alumina, silica-poor (HASP), and ultra Mg glasses. HASP glasses contain insufficient SiO2 to permit the calculation of a standard norm, and are thought to be the product of volatilization during impact melting. They have been studied by electron microprobe major-element analysis techniques but have not previously been analyzed for trace elements. The samples analyzed for this study were polished grain mounts of the 90-160 micron fraction of four sieved samples from the 79001/2 core (depth range 2.3-11.5 cm). A total of 80 glasses were analyzed by SEM/EDS and electron microprobe, and a subset of 33 of the glasses, representing a wide range of compositional types, was chosen for high-sensitivity INAA. A microdrilling device removed disks (mostly 50-100 micron diameter, weighing approx. 0.1-0.5 micro-g) for INAA. Preliminary data reported here are based only on short counts done within two weeks of irradiation.

  17. Is Nasobiliary Tube Really Safe A Case Report

    Directory of Open Access Journals (Sweden)

    Girolamo Geraci

    2011-05-01

    Full Text Available A case of esophageal ulcer caused by nasobiliary tube is described. This tool is not routinely considered to be a cause of major complications in the literature and to our knowledge, this is the first report of this kind of complication in nasobiliary tube placement. A 72-year-old patient presented with Charcot’s triad and was demonstrated to have cholangitis with multiple biliary stones in the common bile duct. Biliary drainage was achieved through endoscopic retrograde cholangiography, endoscopic sphincterotomy, biliary tree drainage and nasobiliary tube with double pigtail. The patient presented odynophagia, dysphagia and retrosternal pain 12 h after the procedure and upper endoscopy revealed a long esophageal ulcer, which was treated conservatively. This report provides corroboration of evidence that nasobiliary tubeplacement has potential complications related to pressure sores. In our opinion this is a possibility to consider in informed consent forms.

  18. Thermomechanical CSM analysis of a superheater tube in transient state

    Science.gov (United States)

    Taler, Dawid; Madejski, Paweł

    2011-12-01

    The paper presents a thermomechanical computational solid mechanics analysis (CSM) of a pipe "double omega", used in the steam superheaters in circulating fluidized bed (CFB) boilers. The complex cross-section shape of the "double omega" tubes requires more precise analysis in order to prevent from failure as a result of the excessive temperature and thermal stresses. The results have been obtained using the finite volume method for transient state of superheater. The calculation was carried out for the section of pipe made of low-alloy steel.

  19. Digital PIV Measurements of Acoustic Particle Displacements in a Normal Incidence Impedance Tube

    Science.gov (United States)

    Humphreys, William M., Jr.; Bartram, Scott M.; Parrott, Tony L.; Jones, Michael G.

    1998-01-01

    Acoustic particle displacements and velocities inside a normal incidence impedance tube have been successfully measured for a variety of pure tone sound fields using Digital Particle Image Velocimetry (DPIV). The DPIV system utilized two 600-mj Nd:YAG lasers to generate a double-pulsed light sheet synchronized with the sound field and used to illuminate a portion of the oscillatory flow inside the tube. A high resolution (1320 x 1035 pixel), 8-bit camera was used to capture double-exposed images of 2.7-micron hollow silicon dioxide tracer particles inside the tube. Classical spatial autocorrelation analysis techniques were used to ascertain the acoustic particle displacements and associated velocities for various sound field intensities and frequencies. The results show that particle displacements spanning a range of 1-60 microns can be measured for incident sound pressure levels of 100-130 dB and for frequencies spanning 500-1000 Hz. The ability to resolve 1 micron particle displacements at sound pressure levels in the 100 dB range allows the use of DPIV systems for measurement of sound fields at much lower sound pressure levels than had been previously possible. Representative impedance tube data as well as an uncertainty analysis for the measurements are presented.

  20. Multi-Stable Conductance States in Metallic Double-Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Ci Lijie

    2009-01-01

    Full Text Available Abstract Electrical transport properties of individual metallic double-walled carbon nanotubes (DWCNTs were measured down to liquid helium temperature, and multi-stable conductance states were found in DWCNTs. At a certain temperature, DWCNTs can switch continuously between two or more electronic states, but below certain temperature, DWCNTs are stable only at one of them. The temperature for switching is always different from tube to tube, and even different from thermal cycle to cycle for the same tube. In addition to thermal activation, gate voltage scanning can also realize such switching among different electronic states. The multi-stable conductance states in metallic DWCNTs can be attributed to different Fermi level or occasional scattering centers induced by different configurations between their inner and outer tubes.

  1. 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

  2. Three Cell Fusions during Double Fertilization.

    Science.gov (United States)

    Sprunck, Stefanie; Dresselhaus, Thomas

    2015-05-07

    Fertilization of both egg and central cell is a major distinguishing feature of flowering plants. Now, Maruyama et al. report a third cell fusion event between the persistent synergid and the fertilized central cell shortly after double fertilization in Arabidopsis. This causes rapid dilution of pollen tube attractant(s), preventing polytubey. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Endotracheal tube defects: Hidden causes of airway obstruction

    Directory of Open Access Journals (Sweden)

    Sofi Khalid

    2010-01-01

    Full Text Available Manufacturing defects of endotracheal tube (ETT are still encountered in anesthesia practice. Many such defects go unnoticed during routine inspection prior to their use. Such defects in ETT may lead to partial or complete airway obstruction in an intubated patient. We report a case of partial airway obstruction with a prepacked, single use, uncuffed ETT due to a manufacturing defect in the form of a plastic meniscus at the distal end of the tube. This case report highlights the significance of standard monitoring of ventilation and the role of a vigilant clinician in detecting such defects in avoiding critical events as can arise from the use of such defective ETTs. It also emphasizes the need for double checking ETTs prior to their use.

  4. Analysis of temperature and stress distribution of superheater tubes after attemperation or sootblower activation

    International Nuclear Information System (INIS)

    Madejski, Paweł; Taler, Dawid

    2013-01-01

    Highlights: • The CFD simulation was used to calculate 3D steam and tube wall temperature distributions in the platen superheater. • The CFD results can be used in design of superheaters made of tubes with complex cross-section. • The CFD analysis enables the proper selection of the steel grade. • The transient temperature and stress distributions were calculated using Finite Volume Method. • The detailed analysis prevents superheater tubes from excessive stresses during sootblower or attemperator activation. - Abstract: Superheaters are characterized by high metal temperatures due to higher steam temperature and low heat transfer coefficients on the tube inner surfaces. Superheaters have especially difficult operating conditions, particularly during attemperator and sootblower activations, when temperature and steam flow rate as well as tube wall temperature change with time. A detailed thermo-mechanical analysis of the superheater tubes makes it possible to identify the cause of premature high-temperature failures and aids greatly in the changes in tubing arrangement and improving start-up technology. This paper presents a thermal and strength analysis of a tubedouble omega”, used in the steam superheaters in CFB boilers

  5. Indian Point 2 steam generator tube rupture analyses

    International Nuclear Information System (INIS)

    Dayan, A.

    1985-01-01

    Analyses were conducted with RETRAN-02 to study consequences of steam generator tube rupture (SGTR) events. The Indian Point, Unit 2, power plant (IP2, PWR) was modeled as a two asymmetric loops, consisting of 27 volumes and 37 junctions. The break section was modeled once, conservatively, as a 150% flow area opening at the wall of the steam generator cold leg plenum, and once as a 200% double-ended tube break. Results revealed 60% overprediction of breakflow rates by the traditional conservative model. Two SGTR transients were studied, one with low-pressure reactor trip and one with an earlier reactor trip via over temperature ΔT. The former is more typical to a plant with low reactor average temperature such as IP2. Transient analyses for a single tube break event over 500 seconds indicated continued primary subcooling and no need for steam line pressure relief. In addition, SGTR transients with reactor trip while the pressurizer still contains water were found to favorably reduce depressurization rates. Comparison of the conservative results with independent LOFTRAN predictions showed good agreement

  6. Measurements of local liquid velocity and interfacial parameters of air-water bubbly flows in a horizontal tube

    International Nuclear Information System (INIS)

    Yang Jian; Zhang Mingyuan; Zhang Chaojie; Su Yuliang

    2002-01-01

    Distribution of local kinematic parameters of air-water bubbly flows in a horizontal tube with an ID of 35 mm was investigated. The local liquid velocity was measured with a cylindrical hot film probe, and local void fraction, bubble frequency and bubble velocity were measured with a double-sensor probe. It was found that the axial liquid velocity has a same profile as that of single liquid phase flow in the lower part of the tube, and it suffers a sudden reduction in the upper part of the tube. With increasing airflow rate, the liquid velocity would increase in the lower part of the tube, and further decrease at the upper part of the tube, respectively. Most bubbles are congested at the upper part of the tube, and the void fraction and bubble frequencies have similar profile and both are asymmetrical with the tube axis with their maximum values located near the upper tube wall

  7. Feasibility study of aluminum beam tube for the collider: An option for no-coating and no-liner

    International Nuclear Information System (INIS)

    Chou, W.

    1994-07-01

    This report proposes to use a single-layer beam tube made of high strength, high resistivity aluminum alloy (such as 7039-T61 or A7N01) to replace the double-layer copper coated stainless steel tube in the SSC Collider. The main reasons are: (1) a potential saving of about $23 million which is basically the baseline cost of the copper coating and (2) the use of an extruded aluminum tube consisting of a beam chamber and a pumping chamber may solve the vacuum problem without any liner

  8. Design of the forward straw tube tracker for the PANDA experiment

    Science.gov (United States)

    Smyrski, J.; Apostolou, A.; Biernat, J.; Czyżycki, W.; Filo, G.; Fioravanti, E.; Fiutowski, T.; Gianotti, P.; Idzik, M.; Korcyl, G.; Korcyl, K.; Lisowski, E.; Lisowski, F.; Płażek, J.; Przyborowski, D.; Przygoda, W.; Ritman, J.; Salabura, P.; Savrie, M.; Strzempek, P.; Swientek, K.; Wintz, P.; Wrońska, A.

    2017-06-01

    The design of the Forward Tracker for the Forward Spectrometer of the PANDA experiment is described. The tracker consists of 6 tracking stations, each comprising 4 planar double layers of straw tube detectors, and has a total material budget of only 2% X0. The straws are made self-supporting by a 1 bar over-pressure of the working gas mixture (Ar/CO2). This allows to use lightweight and compact rectangular support frames for the double layers and to split the frames into pairs of C-shaped half-frames for an easier installation on the beam line.

  9. Dynamic response of INTOR/NET blankets after coolant tube rupture

    International Nuclear Information System (INIS)

    Klippel, H.T.

    1985-01-01

    The dynamic response of different water-cooled liquid Li 17 Pb 83 breeder blanket modules has been calculated to study the potential of these modules in case of coolant tube rupture. Numerical calculations with the code PISCES have been carried out taking into account the fluid-structure interaction and the elasto-plastic behaviour of the structural material. The results show that for inert coolant characteristics the proposed conceptual designs for NET and INTOR have sufficient resistance against coolant tube rupture but when taking into account energy release due to chemical reaction of water with LiPb-alloy up to doubling of the wall thickness has to be envisaged to guarantee structural reliability. (orig.)

  10. Self-assembly of a double-helical complex of sodium.

    Science.gov (United States)

    Bell, T W; Jousselin, H

    1994-02-03

    Spontaneous self-organization of helical and multiple-helical molecular structures occurs on several levels in living organisms. Key examples are alpha-helical polypeptides, double-helical nucleic acids and helical protein structures, including F-actin, microtubules and the protein sheath of the tobacco mosaic virus. Although the self-assembly of double-helical transition-metal complexes bears some resemblance to the molecular organization of double-stranded DNA, selection between monohelical, double-helical and triple-helical structures is determined largely by the size and geometrical preference of the tightly bound metal. Here we present an example of double-helical assembly induced by the weaker and non-directional interactions of an alkali-metal ion with an organic ligand that is pre-organized into a coil. We have characterized the resulting complex by two-dimensional NMR and fast-atom-bombardment mass spectrometry. These results provide a step toward the creation of molecular tubes or ion channels consisting of intertwined coils.

  11. Revisiting the Fully Automated Double-Ring Infiltrometer Using Open-Source Electronics

    Science.gov (United States)

    The double-ring infiltrometer (DRI) is commonly used for measuring soil hydraulic conductivity. However, constant-head DRI tests typically involve the use of Mariotte tubes, which can be problematic to set-up, and time-consuming to maintain and monitor during infiltration tests....

  12. Manufacturing process for cylindrical ceramic tubes with localized imprints and device for application of this process

    International Nuclear Information System (INIS)

    1985-01-01

    This invention involves a process for manufacturing permeable cylindrical ceramic tubes with localized relief such as annular, spiral or simple coiled or double crossed coils or even stipple imprints on their internal face. It is known that one of the techniques for the separation of the mixture of gases with close molecular masses is gaseous diffusion. According to this technique, the gas mixture is circulated under pressure inside tubes constituted by a microporous wall. These tubes, according to a known technique, are constituted by a macroporous ceramic tube, generally called a support, covered on the inside with a microporous layer deposited on this interior wall. The unit constituted by the tube itself or the ''support'' and the microporous layer makes it possible to adapt the total porosity of the covered tube or ''barrier'' in order to obtain an optimal coefficient of gas separation. This technique is used specifically for separation of two gases corresponding to various isotopes of the same simple body. 6 figs

  13. X-ray topography with scintillators coupled to image intensifiers or camera tubes

    International Nuclear Information System (INIS)

    Beauvais, Yves; Mathiot, Alain.

    1978-01-01

    The possibility of imaging topographic figures in real time by using a thin scintillator coupled to either a high-gain image intensifier or a camera tube is investigated. The camera tube must have a high gain because of the low photon fluxes that are encountered in practice, and because of the relatively low quantum yield of thin phosphors. With conventional X-ray generators, the resolution is photon-noise limited. With more powerful generators like synchrotrons, real-time imaging appears possible, and the resolution is limited by the modulation transfer function of the image tube. Higher resolution can be reached by increasing the magnification between the screen and the image tube. When doing so, the input field is reduced and thinner phosphor screens must be used, resulting in a lower yield. Each time the magnification is doubled, the minimum required photon flux is multiplier by about 8, so that the advantages of increasing the magnification are rapidly limited, so far as real-time imaging is concerned. Because image tube resolution is mainly limited by the modulation transfer function of the phosphor for image intensifiers, and by that of the target for camera tubes, improvement of photocathode resolution can be obtained by magnifying electron optics. A zooming electron optic would permit the field and the resolution of the tube to be adapted to the observed subject. Unfortunately such tubes do not exist at present for this type of application, and in the required size

  14. 21 CFR 868.5800 - Tracheostomy tube and tube cuff.

    Science.gov (United States)

    2010-04-01

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

  15. Study of a double bubbler for material balance in liquids

    Energy Technology Data Exchange (ETDEWEB)

    Hugues Lambert

    2013-09-01

    The objective of this project was to determine the potential of a double bubbler to measure density and fluid level of the molten salt contained in an electrorefiner. Such in-situ real-time measurements can provide key information for material balances in the pyroprocessing of the nuclear spent fuel. This theoretical study showed this technique has a lot of promise. Four different experiments were designed and performed. The first three experiments studied the influence of a variety of factors such as depth difference between the two tubes, gas flow rate, the radius of the tubes and determining the best operating conditions. The last experiment purpose was to determine the precision and accuracy of the apparatus during specific conditions. The elected operating conditions for the characterization of the system were a difference of depth of 25 cm and a flow rate of 55 ml/min in each tube. The measured densities were between 1,000 g/l and 1,400g/l and the level between 34cm and 40 cm. The depth difference between the tubes is critical, the larger, the better. The experiments showed that the flow rate should be the same in each tube. The concordances with theoretical predictions were very good. The density precision was very satisfying (spread<0.1%) and the accuracy was about 1%. For the level determination, the precision was also very satisfying (spread<0.1%), but the accuracy was about 3%. However, those two biases could be corrected with calibration curves. In addition to the aqueous systems studied in the present work, future work will focus on examining the behavior of the double bubbler instrumentation in molten salt systems. The two main challenges which were identified in this work are the effect of the temperature and the variation of the superficial tension.

  16. 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

  17. Ultrasonic inspection of tube to tube plate welds

    International Nuclear Information System (INIS)

    Telford, D.W.; Peat, T.S.

    1985-01-01

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

  18. A double cell for X-ray absorption spectrometry of atomic Zn

    CERN Document Server

    Mihelic, A; Arcon, I; Padeznik-Gomilsek, J; Borowski, M

    2002-01-01

    A high-temperature cell with a double wall design has been constructed for X-ray absorption spectrometry of metal vapors. The inner cell, assembled from a corundum tube and thin plates without welding or reshaping, serves as a container of the vapor sample. It is not vacuum tight: instead, the outer tube provides inert atmosphere. Several spectra of K-edge atomic absorption of Zn were obtained in the stationary working regime below the Zn boiling point. The K-edge profile shows an extremely strong resonance and, above the continuum threshold, coexcitations of the outer electrons.

  19. Double-walled ZrO{sub 2} nanotube array. Preparation and enhanced photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Chaorui; Hu, Shengliang; Chang, Qing; Wang, Yanzhong [School of Materials Science and Engineering, North University of China, Taiyuan (China); Yang, Jinlong [School of Materials Science and Engineering, North University of China, Taiyuan (China); School of Materials Science and Engineering, Tsinghua University, Beijing (China)

    2017-11-15

    This work demonstrates the formation of self-ordered double-walled ZrO{sub 2} nanotube array via electrochemical anodization in glycerol-based electrolyte. Compared with its counterpart of single-walled ZrO{sub 2} nanotube array, the tube wall of double-walled ZrO{sub 2} nanotube split into outer and inner layers for the decomposition of glycerol during anodization process. Moreover, the double-walled structure showed its advantage of achieving improved utilization of light and higher specific surface area of nanotube array. Due to the unique double-walled structure, the double-walled ZrO{sub 2} nanotube array exhibited better photocatalytic activity than the single-walled ZrO{sub 2} nanotube array. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Crystal structure and self-interaction of the type VI secretion tail-tube protein from enteroaggregative Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Badreddine Douzi

    Full Text Available The type VI secretion system (T6SS is a widespread machine used by bacteria to control their environment and kill or disable bacterial species or eukaryotes through toxin injection. The T6SS comprises a central tube formed of stacked hexamers of hemolysin co-regulated proteins (Hcp and terminated by a trimeric valine-glycine repeat protein G (VgrG component, the cell puncturing device. A contractile tail sheath, formed by the TssB and TssC proteins, surrounds this tube. This syringe-like machine has been compared to an inverted phage, as both Hcp and VgrG share structural homology with tail components of Caudovirales. Here we solved the crystal structure of a tryptophan-substituted double mutant of Hcp1 from enteroaggregative Escherichia coli and compared it to the structures of other Hcps. Interestingly, we observed that the purified Hcp native protein is unable to form tubes in vitro. To better understand the rationale for observation, we measured the affinity of Hcp1 hexamers with themselves by surface plasmon resonance. The intra-hexamer interaction is weak, with a KD value of 7.2 µM. However, by engineering double cysteine mutants at defined positions, tubes of Hcp1 gathering up to 15 stacked hexamers formed in oxidative conditions. These results, together with those available in the literature regarding TssB and TssC, suggest that assembly of the T6SS tube differs significantly from that of Sipho- or Myoviridae.

  1. Heat Exchanger Tube to Tube Sheet Joints Corrosion Behavior

    Directory of Open Access Journals (Sweden)

    M. Iancu

    2013-03-01

    Full Text Available Paper presents the studies made by the authors above the tube to tube sheet fittings of heat exchanger with fixed covers from hydrofining oil reforming unit. Tube fittings are critical zones for heat exchangers failures. On a device made from material tube and tube sheet at real joints dimensions were establish axial compression force and traction force at which tube is extracted from expanded joint. Were used two shapes joints with two types of fittings surfaces, one with smooth hole of tube sheet and other in which on boring surface we made a groove. From extracted expanded tube zones were made samples for corrosion tests in order to establish the corrosion rate, corrosion potential and corrosion current in working mediums such as hydrofining oil and industrial water at different temperatures. The corrosion rate values and the temperature influence are important to evaluate joints durability and also the results obtained shows that the boring tube sheet shape with a groove on hole tube shape presents a better corrosion behavior then the shape with smooth hole tube sheet.

  2. THE EFFECTS OF SWIRL GENERATOR HAVING WINGS WITH HOLES ON HEAT TRANSFER AND PRESSURE DROP IN TUBE HEAT EXCHANGER

    Directory of Open Access Journals (Sweden)

    Zeki ARGUNHAN

    2006-02-01

    Full Text Available This paper examines the effect of turbulance creators on heat transfer and pressure drop used in concentric heat exchanger experimentaly. Heat exchanger has an inlet tube with 60 mm in diameter. The angle of swirl generators wings is 55º with each wing which has single, double, three and four holes. Swirl generators is designed to easily set to heat exchanger entrance. Air is passing through inner tube of heat exhanger as hot fluid and water is passing outer of inner tube as cool fluid.

  3. Tube spacer grid for a heat-exchanger tube bundle

    International Nuclear Information System (INIS)

    Scheidl, H.

    1976-01-01

    A tube spacer grid for a heat-exchanger tube bundle is formed by an annular grid frame having a groove formed in its inner surface in which the interspaced grid bars have their ends positioned and held in interspaced relationship by short sections of tubes passed through holes axially formed in the grid frame so that the tubes are positioned between the ends of the grid bars in the grooves. The tube sections may be cut from the same tubes used to form the tube bundle. 5 claims, 3 drawing figures

  4. DOUBLE-WALL COLLIMATOR DESIGN OF THE SNS PROJECT

    International Nuclear Information System (INIS)

    SIMOS, N.; LUDEWIG, H.; CATALAN-LASHERAS, N.; CRIVELLO, S.

    2001-01-01

    The collimator absorber array of the Spallation Neutron Source (SNS) project is responsible for stopping the 1.0 GeV protons that are in the halo of the beam. It is estimated that 0.1% of the 2 MW beam will be intercepted by the adopted collimating scheme implemented at various sections of the beam transport and accumulation. This paper summarizes the conceptual design of the collimator absorber as well as the supporting detailed analysis that were performed and guided the design process. Key requirement in the design process is the need for the collimator beam tube to minimize beam impedance while closely following its beta function. Due to lack of available experimental data, the long-term behavior of irradiated materials in an environment where they interface with coolant flow becomes an issue. Uncertainties in the long-term behavior prompted a special double-wall design that will enable not only beam halo interception but also the efficient transfer of deposited energy both under normal and off-normal conditions to the coolant flow. The thermo-mechanical response of the double wall beam tube and of a particle bed surrounding it are discussed in detail in the paper

  5. Flat tile armour cooled by hypervapotron tube: a possible technology for ITER

    International Nuclear Information System (INIS)

    Schlosser, J.; Escourbiac, F.; Bayetti, P.; Missirlian, M.; Mitteau, R.; Schedler, B.; Bobin-Vastra, I.

    2003-01-01

    Carbon fibre composite (CFC) flat tile armours for actively cooled plasma facing components (PFC's) are an important challenge for controlled fusion machine. Flat tile concepts, water cooled by tubes, were studied, developed, tested and finally experienced with success in Tore Supra. The components were designed for 10 MW/m 2 and mock-ups were successfully fatigue tested at 15 MW/m 2 , 1000 cycles. For ITER, a tube-in-tile concept was developed and mock-ups sustained up to 25 MW/m 2 for 1000 cycles without failure. Recently flat tile armored mock-ups cooled by Hypervapotron tube successfully sustained a cascade failure test under a mean heat flux of 10 MW/m 2 but with a doubling of the heat flux on some tiles to simulate missing tiles (500 cycles). This encouraging results lead to reconsider the limits for flat tile concept when cooled by Hypervapotron tube. New tests are now scheduled to investigate these limits notably in regards to the ITER requirements. The concept could also be experimented in Tore Supra by installing a new limiter into the machine. (authors)

  6. A clinical study of fallopian tube recanalization by comptesswely injecting contrast medunm into the uterus

    International Nuclear Information System (INIS)

    Xi Jiayuan; Jiang Yong; Zhu Ying; Gong Hiafeng; Lv Liang; Zhao Xinxiang; Fang Min; Wei Dingying; Hua Jian

    2006-01-01

    Objective: To search for a new, simple, rapid, safe and effective method with combination of hystero. Salingography and fallopian tube recanalization. Methods: After the double-lumen balloon catheter was inserted into the uterine cavity and then followed by saline or air injection into to the saccule. The internal os of cervix was thus blocked by the filled saccule. Iohexol was injected into uterine cavity and fallopian tubes to undertake hystero-salingography and selective radiography under the television observation. In case of obstruction the fallopian tube recanalization could be obtained by manual increasing the contrast injection pressure into the uterine cavity. Results: 2698 cases including 811 primary infertile women and 1887 cases of secondary infertilities were examed by this method. The number of obstructed fallopian tube was 3082 including 1561 right fallopian tubes and 1521 left ones. The rate of tube obstruction was 77.77% and that of tube recanalization was 88.96% including 2397 branches recanalized completely and 322 partially recanalizd. The venous reflux was found in 27 cases and light complications included slight vagina bleeding, mild transient spastic pain without mortality. Conclusion: This method of combining hystero-salinography and fallopian tube recanalization, is safe, effective, economic and practical for infertile women with quick procedure process; and worthy to be recommended. (authors)

  7. Numerical simulation of double-pipe condensers and evaporators

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Valladares, O. [Universidad Nacional Autonoma de Mexico, Morelos (Mexico). Centro de Investigacion en Energia; Perez-Segarra, C.D.; Rigola, J. [Universitat Politecnica de Catalunya, Terrassa (Spain). Centre Tecnologic de Transferencia de Calor, Lab. de Termotecnia i Energetica

    2004-09-01

    A detailed one-dimensional steady and transient numerical simulation of the thermal and fluid-dynamic behaviour of double-pipe heat exchangers (evaporators and condensers) has been carried out. The governing equations (continuity, momentum and energy) inside the internal tube and the annulus, together with the energy equation in the internal tube wall, external tube wall and insulation, are solved iteratively in a segregated manner. The discretized governing equations in the zones with fluid flow are efficiently coupled using an implicit step by step method. This formulation requires the use of empirical correlations for the evaluation of convective heat transfer, shear stress and void fraction. An implicit central difference numerical scheme and a line-by-line solver was used in the internal and external tube walls and insulation. A special treatment has been implemented in order to consider transitions (single-phase/two-phase, dry-out,...). All the flow variables (enthalpies, temperatures, pressures, mass fractions, velocities, heat fluxes,...) together with the thermophysical properties are evaluated at each point of the grid in which the domain is discretized. Different numerical aspects and comparisons with analytical and experimental results are presented in order to verify and validate the model. (author)

  8. Late-onset endophthalmitis secondary to exposed glaucoma tube implant in a rare case of paediatric glaucoma.

    Science.gov (United States)

    Ranganath, Akshatha; Hashim, Adnan

    2011-01-01

    Glaucoma drainage implants (GDIs) are used to treat paediatric glaucoma resistant to conventional medical and surgical treatment, achieving good intraocular pressure (IOP) control and long-term success. Late endophthalmitis is a rare complication that may develop following GDI surgery. A 17-year-old male presented with acute endophthalmitis 2 years after Ahmed glaucoma valve implantation with pericardial patch graft for management of refractory glaucoma secondary to congenital ectropion uveae. The glaucoma tube was exposed due to erosion of the overlying conjunctiva with no visible pericardial graft. After control of active infection, he underwent tube revision surgery whereby the exposed tube was retained and repatched with a double-thickness pericardial patch graft. He did well following surgery with good control of IOP and restoration of vision. Conjunctival dehiscence with graft melting over the GDI tube presented a major risk factor for endophthalmitis. Prompt surgical revision of an exposed tube is highly recommended to avoid ocular morbidity.

  9. Late-Onset Endophthalmitis Secondary to Exposed Glaucoma Tube Implant in a Rare Case of Paediatric Glaucoma

    Directory of Open Access Journals (Sweden)

    Akshatha Ranganath

    2011-01-01

    Full Text Available Glaucoma drainage implants (GDIs are used to treat paediatric glaucoma resistant to conventional medical and surgical treatment, achieving good intraocular pressure (IOP control and long-term success. Late endophthalmitis is a rare complication that may develop following GDI surgery. A 17-year-old male presented with acute endophthalmitis 2 years after Ahmed glaucoma valve implantation with pericardial patch graft for management of refractory glaucoma secondary to congenital ectropion uveae. The glaucoma tube was exposed due to erosion of the overlying conjunctiva with no visible pericardial graft. After control of active infection, he underwent tube revision surgery whereby the exposed tube was retained and repatched with a double-thickness pericardial patch graft. He did well following surgery with good control of IOP and restoration of vision. Conjunctival dehiscence with graft melting over the GDI tube presented a major risk factor for endophthalmitis. Prompt surgical revision of an exposed tube is highly recommended to avoid ocular morbidity.

  10. Double shell planar experiments on OMEGA

    Science.gov (United States)

    Dodd, E. S.; Merritt, E. C.; Palaniyappan, S.; Montgomery, D. S.; Daughton, W. S.; Schmidt, D. W.; Cardenas, T.; Wilson, D. C.; Loomis, E. N.; Batha, S. H.; Ping, Y.; Smalyuk, V. A.; Amendt, P. A.

    2017-10-01

    The double shell project is aimed at fielding neutron-producing capsules at the National Ignition Facility (NIF), in which an outer low-Z ablator collides with an inner high-Z shell to compress the fuel. However, understanding these targets experimentally can be challenging when compared with conventional single shell targets. Halfraum-driven planar targets at OMEGA are being used to study physics issues important to double shell implosions outside of a convergent geometry. Both VISAR and radiography through a tube have advantages over imaging through the hohlraum and double-shell capsule at NIF. A number physics issues are being studied with this platform that include 1-d and higher dimensional effects such as defect-driven hydrodynamic instabilities from engineering features. Additionally, the use of novel materials with controlled density gradients require study in easily diagnosed 1-d systems. This work ultimately feeds back into the NIF capsule platform through manufacturing tolerances set using data from OMEGA. Supported under the US DOE by the LANS, LLC under contract DE-AC52-06NA25396. LA-UR-17-25386.

  11. Radial breathing vibration of double-walled carbon nanotubes subjected to pressure

    International Nuclear Information System (INIS)

    Lei, Xiao-Wen; Natsuki, Toshiaki; Shi, Jin-Xing; Ni, Qing-Qing

    2011-01-01

    A theoretical vibrational analysis of the radial breathing mode (RBM) of double-walled carbon nanotubes (DWCNTs) subjected to pressure is presented based on an elastic continuum model. The results agree with reported experimental results obtained under different conditions. Frequencies of the RBM in DWCNTs subjected to increasing pressure depend strongly on circumferential wave numbers, but weakly on the aspect ratio and axial half-wave numbers. For the inner and outer tubes of DWCNTs, the frequency of the RBM increases obviously as the pressure increases under different conditions. The range of variation is smaller for the inner tube than the outer tube. -- Highlights: → An elastic continuum model is used in the theoretical analysis of RBM of DWCNTs. → The RBM of DWCNTs subjected to pressure is analyzed. → Frequency of RBM depends on wave number and aspect ratio. → Frequencies of RBM in inner and outer tubes change in different trends and ranges.

  12. A fundamental study on sodium-water reaction in the double-pool-type LMFBR

    International Nuclear Information System (INIS)

    Yoshida, Kazuo; Akimoto, Tokuzo

    1987-01-01

    In order to evaluate the pressure rise by large sodium-water reaction in the Double-Pool LMFBR, basic tests on pressure wave celerity in rectangular tube are carried out. The initial spike pressure in rectangular-shelled steam generator of the Double Pool reactor, strongly depends on pressure wave celerity. In this study, celerity was measured as a function of pressure wave rising time and pulse height, and influence of water around the test section on celerity was investigated. (author)

  13. Design and development of multipurpose Kundt’s tube as physics learning media

    Science.gov (United States)

    Nursulistiyo, E.

    2018-03-01

    Research had been conducted to develop Multipurpose Kundt's tube as a physics learning media. Research background was the absence of sound waves visualization to improve the understanding of learners. The purposes of this research were to develop Multipurpose Kundt’s tube as physics learning media and to test its feasibility. The developed tool was tested to find the speed of sound in the air, showing the double slit interference phenomenon of the sound, and show the temperature changes in the cold and heat reservoirs in the thermoacoustic process. The development step that had been used was Preliminary Study, Development, Field Test, and Dissemination or known as PDFD Model. On the implementation, the dissemination process was not done. The test was done by the experts, peers, and college students to find out the media feasibility level. The speed of sound in the air which was measured using Multipurpose Kundt’s tube obtained v ± Δv = 263 ± 24 m/s with the closeness value of 76.63% closer to the theoretical value. Also, it was founded a calibration factor of 1.32. The tool was able to show sound waves on the open-end tube. The value of the distance between minimum and maximum interferences between the experimental results compared to theory was almost the same, so it was concluded that the phenomenon of double-slit interference of the sound could be shown by the tool. The thermoacoustic phenomenon could be observed and gave maximum temperature 31.4°C in the hot reservoir, and minimum temperature 24°C in the cold reservoir at the frequency of 119 Hz. Temperature differences obtained 7.4°C. The result of the feasibility test obtained the average result of 88.23 in a “Very Good” category.

  14. Double-sided microtron at Nihon University

    International Nuclear Information System (INIS)

    Tanaka, T.; Hayakawa, K.; Yatoh, H.; Yoshida, K.; Takeda, O.; Sato, K.; Torizuka, Y.

    1990-01-01

    Construction of a 35 MeV cw double-sided microtron (DSM) at Nihon University was started in 1984 and completed in the spring of 1989. This machine was constructed as a proto-type of an 1 GeV cw double sided microtron for a medical pion facility and test accelerator for FEL and other applications. The 4.55 MeV electron beam from 5 MeV injector linac is injected to the DSM. The energy gain is 6 MeV at each turn acceleration. After recirculated 5 times, the electron beam with 34.5 MeV is extracted at the final short straight section. The DAW structure is used for all the accelerating tubes including the injector linac. Total rf power of 200 kW is provided by four 50 kW klystrons of 2450 MHz. (author)

  15. Tube holding system

    International Nuclear Information System (INIS)

    Cunningham, R.C.

    1978-01-01

    A tube holding rig is described for the lateral support of tubes arranged in tight parcels in a heat exchanger. This tube holding rig includes not less than two tube supporting assemblies, with a space between them, located crosswise with respect to the tubes, each supporting assembly comprising a first set of parallel components in contact with the tubes, whilst a second set of components is also in contact with the tubes. These two sets of parts together define apertures through which the tubes pass [fr

  16. HF electronic tubes. Technologies, grid tubes and klystrons

    International Nuclear Information System (INIS)

    Lemoine, Th.

    2009-01-01

    This article gives an overview of the basic technologies of electronic tubes: cathodes, electronic optics, vacuum and high voltage. Then the grid tubes, klystrons and inductive output tubes (IOT) are introduced. Content: 1 - context and classification; 2 - electronic tube technologies: cathodes, electronic optics, magnetic confinement (linear tubes), periodic permanent magnet (PPM) focussing, collectors, depressed collectors; 3 - vacuum technologies: vacuum quality, surface effects and interaction with electrostatic and RF fields, secondary emission, multipactor effect, thermo-electronic emission; 4 - grid tubes: operation of a triode, tetrodes, dynamic operation and classes of use, 'common grid' and 'common cathode' operation, ranges of utilisation and limitations, operation of a tetrode on unadjusted load, lifetime of a tetrode, uses of grid tubes; 5 - klystrons: operation, impact of space charge, multi-cavity klystrons, interaction efficiency, extended interaction klystrons, relation between interaction efficiency, perveance and efficiency, ranges of utilization and power limitations, multi-beam klystrons and sheet beam klystrons, operation on unadjusted load, klystron band pass and lifetime, uses; 6 - IOT: principle of operation, ranges of utilisation and limitations, interaction efficiency and depressed collector IOT, IOT lifetime and uses. (J.S.)

  17. Delayed hydride cracking behavior of Zr-2.5Nb alloy pressure tubes for PHWR700

    Energy Technology Data Exchange (ETDEWEB)

    Sunil, S.; Bind, A.K.; Khandelwal, H.K.; Singh, R.N., E-mail: rnsingh@barc.gov.in; Chakravartty, J.K.

    2015-11-15

    In order to attain improved in-reactor performance few prototypes pressure tubes of Zr-2.5Nb alloy were manufactured by employing forging to break the cast structure and to obtain more homogeneous microstructure. Both double forging and single forging were employed. The forged material was further processed by employing hot extrusion, cold pilgering and autoclaving. A detailed characterization in terms of mechanical properties and microstructure of the prototype tubes were carried for qualifying it for intended use as pressure tubes in PHWR700 reactors. In this work, Delayed Hydride Cracking (DHC) behavior of the forged Zr-2.5Nb pressure tube material characterized in terms of DHC velocity and threshold stress intensity factor associated with DHC (K{sub IH}) was compared with that of conventionally manufactured material in the temperature range of 200–283 °C. Activation energy associated with the DHC in this alloy was found to be ∼60 kJ/mol for the forged materials.

  18. Flat tile armour cooled by hypervapotron tube: a possible technology for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Schlosser, J.; Escourbiac, F.; Bayetti, P.; Missirlian, M.; Mitteau, R. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Merola, M. [European Fusion Development Agreement - Close Support Unit (EFDA), Garching (Germany); Schedler, B. [Plansee Aktiengesellschaft, Technology Center, Reutte/Tirol (Austria); Bobin-Vastra, I. [FRAMATOME-ANP, Centre Technique, 71 - Le Creusot (France)

    2003-07-01

    Carbon fibre composite (CFC) flat tile armours for actively cooled plasma facing components (PFC's) are an important challenge for controlled fusion machine. Flat tile concepts, water cooled by tubes, were studied, developed, tested and finally experienced with success in Tore Supra. The components were designed for 10 MW/m{sup 2} and mock-ups were successfully fatigue tested at 15 MW/m{sup 2}, 1000 cycles. For ITER, a tube-in-tile concept was developed and mock-ups sustained up to 25 MW/m{sup 2} for 1000 cycles without failure. Recently flat tile armored mock-ups cooled by Hypervapotron tube successfully sustained a cascade failure test under a mean heat flux of 10 MW/m{sup 2} but with a doubling of the heat flux on some tiles to simulate missing tiles (500 cycles). This encouraging results lead to reconsider the limits for flat tile concept when cooled by Hypervapotron tube. New tests are now scheduled to investigate these limits notably in regards to the ITER requirements. The concept could also be experimented in Tore Supra by installing a new limiter into the machine. (authors)

  19. Flat Tile Armour Cooled by Hypervapotron Tube: a Possible Technology for ITER

    Science.gov (United States)

    Schlosser, J.; Escourbiac, F.; Merola, M.; Schedler, B.; Bayetti, P.; Missirlian, M.; Mitteau, R.; Robin-Vastra, I.

    Carbon fibre composite (CFC) flat tile armours for actively cooled plasma facing components (PFC’s) are an important challenge for controlled fusion machines. Flat tile concepts, water cooled by tubes, were studied, developed, tested and finally operated with success in Tore Supra. The components were designed for 10 MW/m2 and mock-ups were successfully fatigue tested at 15 MW/m2, 1000 cycles. For ITER, a tube-in-tile concept was developed and mock-ups sustained up to 25 MW/m2 for 1000 cycles without failure. Recently flat tile armoured mock-ups cooled by a hypervapotron tube successfully sustained a cascade failure test under a mean heat flux of 10 MW/m2 but with a doubling of the heat flux on some tiles to simulate missing tiles (500 cycles). This encouraging results lead to reconsider the limits for flat tile concept when cooled by hypervapotron (HV) tube. New tests are now scheduled to investigate these limits in regard to the ITER requirements. Experimental evidence of the concept could be gained in Tore Supra by installing a new limiter into the machine.

  20. Flat Tile Armour Cooled by Hypervapotron Tube: a Possible Technology for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Schlosser, J.; Escourbiac, F.; Bayetti, P.; Missirlian, M.; Mitteau, R. [Association Euratom CEA, DSM/DRFC/SIPP, St Paul lez Durance (France); Merola, M. [EFDA Close Support Unit, Garching (Germany); Schedler, B. [Plansee Aktiengesellschaft, Reutte (Austria). Technology Center; Bobin-Vastra, I. [Framatome-ANP, Le Creusot (France). Centre Technique

    2004-08-01

    Carbon fibre composite (CFC) flat tile armours for actively cooled plasma facing components (PFC's) are an important challenge for controlled fusion machines. Flat tile concepts, water cooled by tubes, were studied, developed, tested and finally operated with success in Tore Supra. The components were designed for 10MW/m{sup 2} and mock-ups were successfully fatigue tested at 15MW/m{sup 2}; 1000 cycles. For ITER, a tube-in-tile concept was developed and mock-ups sustained up to 25MW/m{sup 2} for 1000 cycles without failure. Recently flat tile armoured mock-ups cooled by a hypervapotron tube successfully sustained a cascade failure test under a mean heat flux of 10MW/m{sup 2} but with a doubling of the heat flux on some tiles to simulate missing tiles (500 cycles). This encouraging results lead to reconsider the limits for flat tile concept when cooled by hypervapotron (HV) tube. New tests are now scheduled to investigate these limits in regard to the ITER requirements. Experimental evidence of the concept could be gained in Tore Supra by installing a new limiter into the machine.

  1. Tube to tube excursive instability - sensitivities and transients

    International Nuclear Information System (INIS)

    Brown, M.; Layland, M.W.

    1980-01-01

    A simple basic analysis of excursive instability in a boiler tube shows how it depends upon operating conditions and physical properties. A detailed mathematical model of an AGR boiler is used to conduct a steady state parameter sensitivity survey. It is possible from this basis to anticipate the effects of changes in operating conditions and changes in design parameters upon tube to tube stability. Dynamic responses of tubes operating near the stability threshold are examined using a mathematical model. Simulated excursions are triggered by imparting small abrupt pressure changes on the boiler inlet pressure. The influences of the magnitude of the pressure change, waterside friction factor and gas side coupling between tubes are examined. (author)

  2. Tube-support response to tube-denting evaluation. Volume 1. Final report

    International Nuclear Information System (INIS)

    Anderson, P.L.; Hall, J.F.; Shah, P.K.; Wills, R.L.

    1983-05-01

    The response of the tube supports is one of the important considerations of tube denting in a steam generator. Investigations have indicated that damaged tube supports have the potential to distort and damage tubes. This investigation considers the response to tube denting of the Combustion Engineering type tube supports. Drilled support plates and eggcrate tube supports are tested in a model steam generator in which tube denting is induced. The experimental data is used to verify and refine analytical predictor models developed using finite element techniques. It was found that analytical models underpredicted the deformations of the tube supports and appropriate modifications to enhance the predictive capability are identified. Non-destructive examination methods are evaluated for application to operating steam generators. It was found that the standard eddy current and profilometry techniques are acceptable methods for determining tube deformations, but these techniques are not adequate to assess tube support damage. Radiography is judged to be the best available means of determining the extent and progression of damage in tube supports

  3. Condenser tube buckling within tube-tubesheet joints

    International Nuclear Information System (INIS)

    Willertz, L.E.; Kalnins, A.; Updike, D.P.

    1991-01-01

    The problem of the appearance of protrusions, or bumps, in the interior of roller-expanded tubes within a tubesheet is addressed. Such bumps have been observed in condensers of power plants. A brief history of the reported occurrences of the bumps is given. The hypothesis is advanced that the mechanics of the formation of the bumps is similar to a buckling problem that has 'bifurcation at infinity'. Following this hypothesis, a two-dimensional physical model is developed, and the application of this model to study a three-dimensional bump is proposed. It is proposed in this paper that an initial deviation from the circular shape of the tube required to produce a bump. It is shown that without such a deviation the tubes cannot buckle. An experiment with short tube segments has been performed that verifies some of the features of the observed condenser tube bumps. Exactly what force produced the initial deviation for the observed bumps is still unknown. Available evidence implicates the hydro-laser jet that is used in the cleaning of tubes and tubesheets. A scenario of how a bump could have been produced by the hydro-laser jet is proposed. (author)

  4. Enhancement of the atomic absorbance of Cr, Zn, Cd, and Pb in metal furnace atomic absorption spectrometry using absorption tubes

    Directory of Open Access Journals (Sweden)

    Yuya Koike

    2017-03-01

    Full Text Available Trace amounts of Cr, Zn, Cd, and Pb were determined by metal furnace atomic absorption spectrometry using absorption tubes. Various absorption tubes were designed as roof- and tube-types, and fixed above the metal furnace in order to extend the light path length. Aqueous standards and samples were injected in the metal furnace and atomized in a metal atomizer with an absorption tube (6 cm length, 15.5 mm diameter. The used of an absorption tube resulted in an enhancement of the atomic absorbance. The ratios of absorbance values with and without the roof- and tube-type absorption tubes were 1.33 and 1.11 for Cr; 1.42 and 1.99 for Zn; 1.66 and 1.98 for Cd; and 1.31 and 1.16 for Pb, respectively. The use of an absorption tube was effective for Zn and Cd analysis, as the absorbance values for these low boiling point metals doubled. The proposed method was successfully applied in the determination of Zn in tap water.

  5. 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 ...

  6. Traveling wave tube and method of manufacture

    Science.gov (United States)

    Vancil, Bernard K. (Inventor)

    2004-01-01

    A traveling wave tube includes a glass or other insulating envelope having a plurality of substantially parallel glass rods supported therewithin which in turn support an electron gun, a collector and an intermediate slow wave structure. The slow wave structure itself provides electrostatic focussing of a central electron beam thereby eliminating the need for focussing magnetics and materially decreasing the cost of construction as well as enabling miniaturization. The slow wave structure advantageously includes cavities along the electron beam through which the r.f. energy is propagated, or a double, interleaved ring loop structure supported by dielectric fins within a ground plane cylinder disposed coaxially within the glass envelope.

  7. Vibro-impact responses of a tube with tube--baffle interaction

    International Nuclear Information System (INIS)

    Shin, Y.S.; Sass, D.E.; Jendrzejczyk, J.A.

    1978-01-01

    The relatively small, inherent tube-to-baffle hole clearances associated with manufacturing tolerances in heat exchangers affect the vibrational characteristics and the response of the tube. Numerical studies were made to predict the vibro-impact response of a tube with tube-baffle interaction. The finite element method has been employed with a non-linear elastic contact spring-dashpot to model the effect of the relative approach between the tube and the baffle plate. The coupled equations of motion are directly integrated with a proportional system damping represented by a linear combination of mass and stiffness. Lumped mass approach with explicit time integration scheme was found to be a suitable choice for tube-baffle impacting analysis. Fourier analyses indicate that the higher mode contributions to the tube response are significant for strong tube-baffle impacting. The contact damping forces are negligible compared with the contact spring forces. The numerical analysis results are in reasonably good agreement with those of the experiments

  8. 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.

  9. Heat conduction in double-walled carbon nanotubes with intertube additional carbon atoms.

    Science.gov (United States)

    Cui, Liu; Feng, Yanhui; Tan, Peng; Zhang, Xinxin

    2015-07-07

    Heat conduction of double-walled carbon nanotubes (DWCNTs) with intertube additional carbon atoms was investigated for the first time using a molecular dynamics method. By analyzing the phonon vibrational density of states (VDOS), we revealed that the intertube additional atoms weak the heat conduction along the tube axis. Moreover, the phonon participation ratio (PR) demonstrates that the heat transfer in DWCNTs is dominated by low frequency modes. The added atoms cause the mode weight factor (MWF) of the outer tube to decrease and that of the inner tube to increase, which implies a lower thermal conductivity. The effects of temperature, tube length, and the number and distribution of added atoms were studied. Furthermore, an orthogonal array testing strategy was designed to identify the most important structural factor. It is indicated that the tendencies of thermal conductivity of DWCNTs with added atoms change with temperature and length are similar to bare ones. In addition, thermal conductivity decreases with the increasing number of added atoms, more evidently for atom addition concentrated at some cross-sections rather than uniform addition along the tube length. Simultaneously, the number of added atoms at each cross-section has a considerably more remarkable impact, compared to the tube length and the density of chosen cross-sections to add atoms.

  10. Pressure tube reactor

    International Nuclear Information System (INIS)

    Susuki, Akira; Murata, Shigeto; Minato, Akihiko.

    1993-01-01

    In a pressure tube reactor, a reactor core is constituted by arranging more than two units of a minimum unit combination of a moderator sealing pipe containing a calandria tube having moderators there between and a calandria tube and moderators. The upper header and a lower header of the calandria tank containing moderators are communicated by way of the moderator sealing tube. Further, a gravitationally dropping mechanism is disposed for injecting neutron absorbing liquid to a calandria gas injection portion. A ratio between a moderator volume and a fuel volume is defined as a function of the inner diameter of the moderator sealing tube, the outer diameter of the calandria tube and the diameter of fuel pellets, and has no influence to intervals of a pressure tube lattice. The interval of the pressure tube lattice is enlarged without increasing the size of the pressure tube, to improve production efficiency of the reactor and set a coolant void coefficient more negative, thereby enabling to improve self controllability and safety. Further, the reactor scram can be conducted by injecting neutron absorbing liquid. (N.H.)

  11. Double-ended metal halide arc discharge lamp with electrically isolated containment shroud

    Science.gov (United States)

    Muzeroll, Martin M. (Inventor)

    1994-01-01

    A double-ended arc discharge lamp includes a sealed, light-transmissive outer jacket, a light-transmissive shroud mounted within the outer jacket and directly supported by the outer jacket, and an arc discharge tube mounted within the shroud. The arc tube is typically a metal halide arc discharge tube. In a preferred embodiment, the shroud includes an outwardly flared portion at each end. The outwardly flared portions space the shroud from the outer jacket and support the shroud within the outer jacket. The outwardly flared portions of the shroud can be affixed to the outer jacket by fusing. The outer jacket can be provided with inwardly extending dimples for locating the shroud with respect to the outer jacket. In another embodiment, the outer jacket includes reduced diameter portions near each end which are attached to the shroud.

  12. Vertical steam generator with slab-type tube-plate with even tube bundle washing

    International Nuclear Information System (INIS)

    Manek, O.; Masek, V.; Motejl, V.; Quitta, R.

    1980-01-01

    A shielding plate supporting the tubes attached to the tube plate of a vertical steam generator is mounted above the tube plate. Tube sleeves are designed with a dimensional tolerance relative to the heat transfer tubes and the sleeve end and the tube plate end. A separate space is thus formed above the tube plate in which circulation or feed water is introduced to flow between the branch and the heat transfer tube. This provides intensive washing of heat transfer tubes at a critical point and prevents deposit formation, thus excluding heat transfer tube failures. (J.B.)

  13. A pulse tube cryocooler with a cold reservoir

    Science.gov (United States)

    Zhang, X. B.; Zhang, K. H.; Qiu, L. M.; Gan, Z. H.; Shen, X.; Xiang, S. J.

    2013-02-01

    Phase difference between pressure wave and mass flow is decisive to the cooling capacity of regenerative cryocoolers. Unlike the direct phase shifting using a piston or displacer in conventional Stirling or GM cryocoolers, the pulse tube cyocooler (PTC) indirectly adjusts the cold phase due to the absence of moving parts at the cold end. The present paper proposed and validated theoretically and experimentally a novel configuration of PTC, termed cold reservoir PTC, in which a reservoir together with an adjustable orifice is connected to the cold end of the pulse tube. The impedance from the additional orifice to the cold end helps to increase the mass flow in phase with the pressure wave at the cold end. Theoretical analyses with the linear model for the orifice and double-inlet PTCs indicate that the cooling performance can be improved by introducing the cold reservoir. The preliminary experiments with a home-made single-stage GM PTC further validated the results on the premise of minor opening of the cold-end orifice.

  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. 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

  16. Improvement of pump tubes for gas guns and shock tube drivers

    Science.gov (United States)

    Bogdanoff, D. W.

    1990-01-01

    In a pump tube, a gas is mechanically compressed, producing very high pressures and sound speeds. The intensely heated gas produced in such a tube can be used to drive light gas guns and shock tubes. Three concepts are presented that have the potential to allow substantial reductions in the size and mass of the pump tube to be achieved. The first concept involves the use of one or more diaphragms in the pump tube, thus replacing a single compression process by multiple, successive compressions. The second concept involves a radical reduction in the length-to-diameter ratio of the pump tube and the pump tube piston. The third concept involves shock heating of the working gas by high explosives in a cyclindrical geometry reusable device. Preliminary design analyses are performed on all three concepts and they appear to be quite feasible. Reductions in the length and mass of the pump tube by factors up to about 11 and about 7, respectively, are predicted, relative to a benchmark conventional pump tube.

  17. 0011-0030.IEEE 754: 64 Bit Double Precision FloatsThis.pdf | 01 ...

    Indian Academy of Sciences (India)

    Home; public; Volumes; reso; 021; 01; 0011-0030.IEEE 754: 64 Bit Double Precision FloatsThis.pdf. 404! error. The page your are looking for can not be found! Please check the link or use the navigation bar at the top. YouTube; Twitter; Facebook; Blog. Academy News. IAS Logo. 29th Mid-year meeting. Posted on 19 ...

  18. The study on a gas-coupled two-stage stirling-type pulse tube cryocooler

    Science.gov (United States)

    Wu, X. L.; Chen, L. B.; Zhu, X. S.; Pan, C. Z.; Guo, J.; Wang, J. J.; Zhou, Y.

    2017-12-01

    A two-stage gas-coupled Stirling-type pulse tube cryocooler (SPTC) driven by a linear dual-opposed compressor has been designed, manufactured and tested. Both of the stages adopted coaxial structure for compactness. The effect of a cold double-inlet at the second stage on the cooling performance was investigated. The test results show that the cold double-inlet will help to achieve a lower cooling temperature, but it is not conducive to achieving a higher cooling capacity. At present, without the cold double-inlet, the second stage has achieved a no-load temperature of 11.28 K and a cooling capacity of 620 mW/20 K with an input electric power of 450 W. With the cold double-inlet, the no-load temperature is lowered to 9.4 K, but the cooling capacity is reduced to 400 mW/20 K. The structure of the developed cryocooler and the influences of charge pressure, operating frequency and hot end temperature will also be introduced in this paper.

  19. Vibro-impact responses of a tube with tube--baffle interaction. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Y S; Sass, D E; Jendrzejczyk, J A

    1978-01-01

    The relatively small, inherent tube-to-baffle hole clearances associated with manufacturing tolerances in heat exchangers affect the vibrational characteristics and the response of the tube. Numerical studies were made to predict the vibro-impact response of a tube with tube-baffle interaction. The finite element method has been employed with a non-linear elastic contact spring-dashpot to model the effect of the relative approach between the tube and the baffle plate. The coupled equations of motion are directly integrated with a proportional system damping represented by a linear combination of mass and stiffness. Lumped mass approach with explicit time integration scheme was found to be a suitable choice for tube-baffle impacting analysis. Fourier analyses indicate that the higher mode contributions to the tube response are significant for strong tube-baffle impacting. The contact damping forces are negligible compared with the contact spring forces. The numerical analysis results are in reasonably good agreement with those of the experiments.

  20. Bender/Coiler for Tubing

    Science.gov (United States)

    Stoltzfus, J. M.

    1983-01-01

    Easy-to-use tool makes coils of tubing. Tubing to be bend clamped with stop post. Die positioned snugly against tubing. Operator turns handle to slide die along tubing, pushing tubing into spiral groove on mandrel.

  1. A Novel Occulta-Type Spina Bifida Mediated by Murine Double Heterozygotes EphA2 and EphA4 Receptor Tyrosine Kinases

    Directory of Open Access Journals (Sweden)

    Nor Linda Abdullah

    2017-12-01

    Full Text Available Members of the Eph receptor tyrosine kinase have previously been implicated in cranial neural tube development. Failure of neural tube closure leads to the devastating conditions known as anencephaly and spina bifida. EphA2 and EphA4 are expressed at the tips of the closing spinal neural folds prior and during neural tube closure. We investigated the possible role of murine EphA2 and EphA4 during the last step of primary neural tube closure, which is adhesion and fusion. The individual mouse knockouts of EphA2 and EphA4 per se do not exhibit neural tube defects (NTDs. The embryos generated by the crossing of double heterozygotes Epha2tm1Jrui/+Epha4rb-2J/+ displayed NTDs with a wide degree of severity including close exencephaly and close spina bifida (spina bifida occulta. Interestingly, mutants displaying NTDs had skin covering the underlying lesion. The tissue sections revealed the elevated neural folds had not adhered and fused. The phenotypes seen in Epha2tm1Jrui/+Epha4rb-2J/+ double heterozygous embryos suggest both genes play a compensatory role with each other in the adhesion and fusion of the neural tube. In this study, there exists a >50% penetrance of NTDs in the mouse mutants, which genetically have a single allele each of EphA2 and EphA4 absent.

  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. Optimization of a Two Stage Pulse Tube Refrigerator for the Integrated Current Lead System

    Science.gov (United States)

    Maekawa, R.; Matsubara, Y.; Okada, A.; Takami, S.; Konno, M.; Tomioka, A.; Imayoshi, T.; Hayashi, H.; Mito, T.

    2008-03-01

    Implementation of a conventional current lead with a pulse tube refrigerator has been validated to be working as an Integrated Current Lead (ICL) system for the Superconducting Magnetic Energy Storage (SMES). Realization of the system is primarily accounted for the flexibility of a pulse tube refrigerator, which does not posses any mechanical piston and/or displacer. As for an ultimate version of the ICL system, a High Temperature Superconducting (HTS) lead links a superconducting coil with a conventional copper lead. To ensure the minimization of heat loads to the superconducting coil, a pulse tube refrigerator has been upgraded to have a second cooling stage. This arrangement reduces not only the heat loads to the superconducting coil but also the operating cost for a SMES system. A prototype two-stage pulse tube refrigerator, series connected arrangement, was designed and fabricated to satisfy the requirements for the ICL system. Operation of the first stage refrigerator is a four-valve mode, while the second stage utilizes a double inlet configuration to ensure its confined geometry. The paper discusses the optimization of second stage cooling to validate the conceptual design

  4. Feeding tube - infants

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007235.htm Feeding tube - infants To use the sharing features on this page, please enable JavaScript. A feeding tube is a small, soft, plastic tube placed ...

  5. Eustachian tube patency

    Science.gov (United States)

    Eustachian tube patency refers to how much the eustachian tube is open. The eustachian tube runs between the middle ear and the throat. It controls the pressure behind the eardrum and middle ear space. This helps keep ...

  6. Numerical investigation of conjugate heat transfer and flow performance of a fin and tube heat exchanger with vortex generators

    DEFF Research Database (Denmark)

    Singh, Shobhana; Sørensen, Kim

    2017-01-01

    Vortex generator is considered as an effective device for augmentation of the thermal-hydraulic performance of a heat exchanger. The aim of present study is to examine the influence of vortex generators on a double fin and tube heat exchanger performance. Vortex generator of rectangular winglet...

  7. Performance study of a fin and tube heat exchanger with different fin geometry

    DEFF Research Database (Denmark)

    Singh, Shobhana; Sørensen, Kim; Condra, Thomas Joseph

    2016-01-01

    This study analyses the effect of different fin geometries on the heat transfer and pressure loss characteristics of a fin and tube heat exchanger. A numerical investigation is carried out on liquid–gas type double-finned tube heat exchanger under cross-flow condition. Three different cross......-sections namely: a) Rectangular, b) Trapezoidal, c) Triangular are adopted to define the fin geometry. The CFD simulations are performed to incorporate coupled steady state conjugate heat transfer with the turbulent flow phenomenon for the Reynolds number in the range of 5000-13000. Dimensionless heat transfer...... models show that triangular fin geometry can provide higher heat transfer performance in comparison to the fins with rectangular and trapezoidal geometry with lower pressure loss and a bonus of 7.27% reduction in weight under similar operating conditions....

  8. Effect of tube-support interaction on the dynamic responses of heat exchanger tubes

    International Nuclear Information System (INIS)

    Shin, Y.S.; Jendrzejczyk, J.A.; Wambsganss, M.W.

    1977-01-01

    Operating heat exchangers have experienced tube damages due to excessive flow-induced vibration. The relatively small inherent tube-to-baffle hole clearances associated with manufacturing tolerances in heat exchangers affect the tube vibrational characteristics. In attempting a theoretical analysis, questions arise as to the effects of tube-baffle impacting on dynamic responses. Experiments were performed to determine the effects of tube-baffle impacting in vertical/horizontal tube orientation, and in air/water medium on the vibrational characteristics (resonant frequencies, mode shapes, and damping) and displacement response amplitudes of a seven-span tube model. The tube and support conditions were prototypic, and overall length approximately one-third that of a straight tube segment of the steam generator designed for the CRBR. The test results were compared with the analytical results based on the multispan beam with ''knife-edge'' supports

  9. Successful 1:1 proportion ventilation with a unique device for independent lung ventilation using a double-lumen tube without complications in the supine and lateral decubitus positions. A pilot study.

    Directory of Open Access Journals (Sweden)

    Michał Kowalczyk

    Full Text Available Adequate blood oxygenation and ventilation/perfusion matching should be main goal of anaesthetic and intensive care management. At present, one of the methods of improving gas exchange restricted by ventilation/perfusion mismatching is independent ventilation with two ventilators. Recently, however, a unique device has been developed, enabling ventilation of independent lungs in 1:1, 2:1, 3:1, and 5:1 proportions. The main goal of the study was to evaluate the device's utility, precision and impact on pulmonary mechanics. Secondly- to measure the gas distribution in supine and lateral decubitus position.69 patients who underwent elective thoracic surgery were eligible for the study. During general anaesthesia, after double lumen tube intubation, the aforementioned control system was placed between the anaesthetic machine and the patient. In the supine and lateral decubitus (left/right positions, measurements of conventional and independent (1:1 proportion ventilation were performed separately for each lung, including the following: tidal volume, peak pressure and dynamic compliance.Our results show that conventional ventilation using Robertshaw tube in the supine position directs 47% of the tidal volume to the left lung and 53% to the right lung. Furthermore, in the left lateral position, 44% is directed to the dependent lung and 56% to the non-dependent lung. In the right lateral position, 49% is directed to the dependent lung and 51% to the non-dependent lung. The control system positively affected non-dependent and dependent lung ventilation by delivering equal tidal volumes into both lungs with no adverse effects, regardless of patient's position.We report that gas distribution is uneven during conventional ventilation using Robertshaw tube in the supine and lateral decubitus positions. However, this recently released control system enables precise and safe independent ventilation in the supine and the left and right lateral decubitus

  10. Annular gap measurement between pressure tube and calandria tube by eddy current technique

    International Nuclear Information System (INIS)

    Bhole, V.M.; Rastogi, P.K.; Kulkarni, P.G.

    1992-01-01

    In pressurised heavy water reactor (PHWR) major distinguishing feature is that there are number of identical fuel channels in the reactor core. Each channel consists of pressure tube of Zr-2.5 Nb or zircaloy-2 through which high temperature, high pressure primary coolant is passing. The pressure tube contains fuel. Surrounding the pressure tube there is low pressure, cool heavy water (moderator). The moderator is thermally separated from coolant by the tube which is nominally concentric with pressure tube called calandria tube. There are four garter springs in the annular gap between pressure tube and calandria tube. During the life of the reactor there are number of factors by which the pressure tube sags, most important factors are irradiation creep, thermal creep, fuel load etc. Because of the sag of pressure tube it can touch the calandria tube resulting in formation of cold spot. This leads to hydrogen concentration at that spot by which the material at that place becomes brittle and can lead to catastrophic failure of pressure tube. There is no useful access for measurement of annular gap either through the gas annular space or from exterior of calandria tube. So the annular gap was measured from inside surface of pressure tube which is accessible. Eddy current technique was used for finding the gap. The paper describe the details of split coil design of bobbin probe, selection of operating point on normalised impedance diagram by choosing frequency. Experimental results on full scale mock up, and actual gap measurement in reactor channel, are also given. (author). 7 figs

  11. Categorising YouTube

    DEFF Research Database (Denmark)

    Simonsen, Thomas Mosebo

    2011-01-01

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

  12. The Effects of Triggering Mechanisms on the Energy Absorption Capability of Circular Jute/Epoxy Composite Tubes under Quasi-Static Axial Loading

    Science.gov (United States)

    Sivagurunathan, Rubentheran; Lau Tze Way, Saijod; Sivagurunathan, Linkesvaran; Yaakob, Mohd. Yuhazri

    2018-01-01

    The usage of composite materials have been improving over the years due to its superior mechanical properties such as high tensile strength, high energy absorption capability, and corrosion resistance. In this present study, the energy absorption capability of circular jute/epoxy composite tubes were tested and evaluated. To induce the progressive crushing of the composite tubes, four different types of triggering mechanisms were used which were the non-trigger, single chamfered trigger, double chamfered trigger and tulip trigger. Quasi-static axial loading test was carried out to understand the deformation patterns and the load-displacement characteristics for each composite tube. Besides that, the influence of energy absorption, crush force efficiency, peak load, mean load and load-displacement history were examined and discussed. The primary results displayed a significant influence on the energy absorption capability provided that stable progressive crushing occurred mostly in the triggered tubes compared to the non-triggered tubes. Overall, the tulip trigger configuration attributed the highest energy absorption.

  13. Fracture toughness behaviour using small CCT specimen of Zr-2.5Nb pressure tube materials

    International Nuclear Information System (INIS)

    Oh, Dong Joon; Kim, Young Suk; Ahn, Sang Bok; Im, Kyung Soo; Kwon, Sang Chul; Cheong, Yong Mu

    2001-03-01

    Fracture toughness of Zr-2.5Nb pressure tube is the essential data to estimate the CCL(critical crack length) for the concept of LBB(Leak-Before-Break) in PHWR. Zr-2.5Nb pressure tubes could be degraded due to the absorption of hydrogen from coolant and the irradiation. To investigate the fracture toughness behaviour such as J-resistance curves, dJ/da, and CCL of some Zr-alloys (CANDU-double, -quad, CW-E125, TMT-E125, E-635), the transverse tensile test and the fracture toughness test of small CCT (Curved Compact Tension) specimen with 17 mm width were carried out with the variation of testing temperature at different testing condition. To define the fracture mechanism of degradation, the fractographic comparison of fracture surface was performed using the stereoscope and SEM. In addition, the effect of non-uniformed pre-fatigue crack was also studied. In conclusion, CANDU double-melted was less tougher than CANDU quad-melted and the hydrogen embrittlement was found at room temperature. Finally, while the effect of non-uniformed pre-fatigue crack was considerable at room temperature, this effect was disappeared at 250-300 .deg. C

  14. Pressure tube type reactors

    International Nuclear Information System (INIS)

    Komada, Masaoki.

    1981-01-01

    Purpose: To increase the safety of pressure tube type reactors by providing an additional ECCS system to an ordinary ECCS system and injecting heavy water in the reactor core tank into pressure tubes upon fractures of the tubes. Constitution: Upon fractures of pressure tubes, reduction of the pressure in the fractured tubes to the atmospheric pressure in confirmed and the electromagnetic valve is operated to completely isolate the pressure tubes from the fractured portion. Then, the heavy water in the reactor core tank flows into and spontaneously recycles through the pressure tubes to cool the fuels in the tube to prevent their meltdown. By additionally providing the separate ECCS system to the ordinary ECCS system, fuels can be cooled upon loss of coolant accidents to improve the safety of the reactors. (Moriyama, K.)

  15. 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.)

  16. Clinical application of hysterosalpingography with a double-lumen catheter of a contrast media combination consisting iohexol and saline

    International Nuclear Information System (INIS)

    Xi Jiayuan; Jiang Yong; Cao Xinhua; Zhu Ying; Lv Liang; Zhao Xinxiang; Wei Dingying; Shao Jingxuan; Hua Jian

    2005-01-01

    Objective: To evaluate the clinical value of hysteosalpingographic diagnosis in infertile women. Methods: After a catheter with a double-lumen saccule was inserted into the uterine cavity, saline or air of 2.5-3.5 ml was injected to fill the saccule. The filled saccule was inserted at the isthmus of uterus for blocking the internal orifice. The contrast medium was injected through the catheter into the uterine cavity and fallopian tubes to undertake hysterosalpingography and fallopian tube reopening. In case of fallopian tube obstruction, the injection pressure could be increased to obtain recanalization. All operations and selective imagings were carried out under TV supervision. Results: 2698 cases including 806 primary infertile women and 1868 secondary infertile women were examined by this method. Technical success rate was 99.5% with 2198 cases (81.9%) having normal uterus, 249 (9.3%) congenital abnormal uterus and 238 (8.9%) uterus diseases. The number of obstructed fallopian tube was 3028 with 117 serious hydropsy (3.8%). Ninety-eight cases had been examined with lipiodol hysterosalpingography in other hospitals with 35 cases still having lipiodol accumulated within the uterine cavities and fallopian tubes. No serious complications or death occurred except slight pain. Conclusions: Double-lumen cather with a contrast media combination of iohexol and saline for hysterosal pinography is safe, easy and effective, outcoming with excellent quality images. More information can be gained with this method than traditional lipiodol hyterosalpinography, and furthermore could have compression during radiogrophy and avoid the long term stasis of lipiodol. (authors)

  17. Heat exchanger tube tool

    International Nuclear Information System (INIS)

    Gugel, G.

    1976-01-01

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

  18. Observation of "YouTube" Language Learning Videos ("YouTube" LLVS)

    Science.gov (United States)

    Alhamami, Munassir

    2013-01-01

    This paper navigates into the "YouTube" website as one of the most usable online tools to learn languages these days. The paper focuses on two issues in creating "YouTube" language learning videos: pedagogy and technology. After observing the existing "YouTube" LLVs, the study presents a novel rubric that is directed…

  19. An experimental investigation of performance of a double pass solar air heater with thermal storage medium

    Directory of Open Access Journals (Sweden)

    Ali Hafiz Muhammad

    2015-01-01

    Full Text Available The performance of a double pass solar air heater was experimentally investigated using four different configurations. First configuration contained only absorber plate whereas copper tubes filled with thermal storage medium (paraffin wax were added on the absorber plate in the second configuration. Aluminum and steel rods as thermal enhancer were inserted in the middle of paraffin wax of each tube for configurations three and four respectively. Second configuration provided useful heat for about 1.5 hours after the sunset compared to first configuration. Configurations three and four provided useful heat for about 2 hours after the sunset. The maximum efficiency of about 96% was achieved using configuration three (i.e. using Aluminum rods in the middle of copper tubes filled with paraffin wax.

  20. 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

  1. Helically coiled tube heat exchanger

    International Nuclear Information System (INIS)

    Harris, A.M.

    1981-01-01

    In a heat exchanger such as a steam generator for a nuclear reactor, two or more bundles of helically coiled tubes are arranged in series with the tubes in each bundle integrally continuing through the tube bundles arranged in series therewith. Pitch values for the tubing in any pair of tube bundles, taken transverse to the path of the reactor coolant flow about the tubes, are selected as a ratio of two unequal integers to permit efficient operation of each tube bundle while maintaining the various tube bundles of the heat exchanger within a compact envelope. Preferably, the helix angle and tube pitch parallel to the path of coolant flow are constant for all tubes in a single bundle so that the tubes are of approximately the same length within each bundle

  2. Categorising YouTube

    OpenAIRE

    Simonsen, Thomas Mosebo

    2011-01-01

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

  3. Real-time tracheal ultrasonography for confirmation of endotracheal tube placement during cardiopulmonary resuscitation.

    Science.gov (United States)

    Chou, Hao-Chang; Chong, Kah-Meng; Sim, Shyh-Shyong; Ma, Matthew Huei-Ming; Liu, Shih-Hung; Chen, Nai-Chuan; Wu, Meng-Che; Fu, Chia-Ming; Wang, Chih-Hung; Lee, Chien-Chang; Lien, Wan-Ching; Chen, Shyr-Chyr

    2013-12-01

    This study aimed to evaluate the accuracy of tracheal ultrasonography for assessing endotracheal tube position during cardiopulmonary resuscitation (CPR). We performed a prospective observational study of patients undergoing emergency intubation during CPR. Real-time tracheal ultrasonography was performed during the intubation with the transducer placed transversely just above the suprasternal notch, to assess for endotracheal tube positioning and exclude esophageal intubation. The position of trachea was identified by a hyperechoic air-mucosa (A-M) interface with posterior reverberation artifact (comet-tail artifact). The endotracheal tube position was defined as endotracheal if single A-M interface with comet-tail artifact was observed. Endotracheal tube position was defined as intraesophageal if a second A-M interface appeared, suggesting a false second airway (double tract sign). The gold standard of correct endotracheal intubation was the combination of clinical auscultation and quantitative waveform capnography. The main outcome was the accuracy of tracheal ultrasonography in assessing endotracheal tube position during CPR. Among the 89 patients enrolled, 7 (7.8%) had esophageal intubations. The sensitivity, specificity, positive predictive value, and negative predictive value of tracheal ultrasonography were 100% (95% confidence interval [CI]: 94.4-100%), 85.7% (95% CI: 42.0-99.2%), 98.8% (95% CI: 92.5-99.0%) and 100% (95% CI: 54.7-100%), respectively. Positive and negative likelihood ratios were 7.0 (95% CI: 1.1-43.0) and 0.0, respectively. Real-time tracheal ultrasonography is an accurate method for identifying endotracheal tube position during CPR without the need for interruption of chest compression. Tracheal ultrasonography in resuscitation management may serve as a powerful adjunct in trained hands. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  4. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... YouTube Videos » NEI YouTube Videos: Amblyopia Listen NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration ... Retinopathy of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia Embedded video for NEI YouTube Videos: ...

  5. Effect of Tube Pitch on Pool Boiling Heat Transfer of Vertical Tube Bundle

    International Nuclear Information System (INIS)

    Kang, Myeong Gie

    2016-01-01

    Summarizing the previous results it can be stated that heat transfer coefficients are highly dependent on the tube pitch and the heat flux of the relevant tube. The published results are mostly about the horizontal tubes. However, there are many heat exchangers consisting of vertical tubes like AP600. Therefore, the focus of the present study is an identification of the effects of a tube pitch as well as the heat flux of a relevant tube on the heat transfer of a tube bundle installed vertically. When the heat flux is increased many bubbles are generating due to the increase of the nucleation sites. The bubbles become coalescing with the nearby bubbles and generates big bunches of bubbles on the tube surface. This prevents the access of the liquid to the surface and deteriorates heat transfer. The bubble coalescence is competing with the mechanisms enhancing heat transfer. The pitch was varied from 28.5 mm to 95 mm and the heat flux of the nearby tube was changed from 0 to 90kW/m"2. The enhancement of the heat transfer is clearly observed when the heat flux of the nearby tube becomes larger and the heat flux of the upper tube is less than 40kW/m"2. The effect of the tube pitch on heat transfer is negligible as the value of DP/ is increased more than 4.

  6. Optimizing Tube Precurvature to Enhance Elastic Stability of Concentric Tube Robots.

    Science.gov (United States)

    Ha, Junhyoung; Park, Frank C; Dupont, Pierre E

    2017-02-01

    Robotic instruments based on concentric tube technology are well suited to minimally invasive surgery since they are slender, can navigate inside small cavities and can reach around sensitive tissues by taking on shapes of varying curvature. Elastic instabilities can arise, however, when rotating one precurved tube inside another. In contrast to prior work that considered only tubes of piecewise constant precurvature, we allow precurvature to vary along the tube's arc length. Stability conditions for a planar tube pair are derived and used to formulate an optimal design problem. An analytic formulation of the optimal precurvature function is derived that achieves a desired tip orientation range while maximizing stability and respecting bending strain limits. This formulation also includes straight transmission segments at the proximal ends of the tubes. The result, confirmed by both numerical and physical experiment, enables designs with enhanced stability in comparison to designs of constant precurvature.

  7. First attempts to combine capillary tubes with photocathodes

    CERN Document Server

    Peskov, Vladimir; Sokolova, T; Radionov, I

    1999-01-01

    We describe our efforts to combine glass capillary plates, operating as a gas amplification structure at approx 1 atm, with photocathodes sensitive to visible light. Such capillary tubes are a by-product of the manufacture of Microchannel Plates and are commercially available. Preliminary tests indicate that gas gains >10 sup 3 could be achieved without photon feedback. With two capillary plates in tandem (double-step multiplication) overall gains up to 10 sup 5 were possible at counting rate <100 Hz/mm sup 2. This approach may open new possibilities for detection of visible photons by gaseous detectors. Potential advantages are: high gains, large sensitive area, high granularity, and insensitivity to magnetic fields.

  8. High efficiency 40 K single-stage Stirling-type pulse tube cryocooler

    Science.gov (United States)

    Wu, X. L.; Chen, L. B.; Pan, C. Z.; Cui, C.; Wang, J. J.; Zhou, Y.

    2017-12-01

    A high efficiency single-stage Stirling-type coaxial pulse tube cryocooler (SPTC) operating at around 40 K has been designed, built and tested. The double-inlet and the inertance tubes together with the gas reservoir were adopted as the phase shifters. Under the conditions of 2.5 MPa charging pressure and 30 Hz operating frequency, the prototype has achieved a no-load temperature of 23.8 K with 330 W of electric input power at a rejection temperature of 279 K. When the input power increases to 400 W, it can achieve a cooling capacity of 4.7 W/40 K while rejecting heat at 279 K yielding an efficiency of 7.02% relative to Carnot. It achieves a cooling capacity of 5 W/40 K with an input power of 450 W. It takes 10 minutes for the SPTC to cool to its no-load temperature of 40 K from 295 K.

  9. A Method to Establishing Tube Plugging Criterion for Heat Exchangers with Straight Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyungnam [KHNP CRI, Daejeon (Korea, Republic of)

    2016-10-15

    The difference of thermal expansion coefficients between the shell and tube materials causes the stress in axial direction of tube. Because of the axial stress due to thermal load, the straight tubes are used for heat exchangers operated in low temperature such as CCW (Component Cooling Water) heat exchangers and condensers. It is inevitable for the materials of the components to be degraded as the power plants become older. The degradation accompanies increasing maintenance cost as well as creating safety issues. The materials and wall thickness of heat exchanger tubes in nuclear power plants are selected to withstand system temperature, pressure, and corrosion. There are many codes and standards to be referred for calculating the minimum thickness of the heat exchanger tube in the designing stage. However, the codes and standards related to show the tube plugging criteria may not exist currently. In this paper, a method to establish the tube plugging criteria of BOP heat exchangers, which is based on the USNRC Regulatory Guide 1.121, is introduced and the tube plugging criteria for the TPCCW heat exchanger of Yonggwang NPP No. 1 and 2. A method to establish the tube plugging criteria of heat exchangers with straight tubes are introduced based on the USNRC Regulatory Guide 1.121. As an example, the tube plugging criterion for the CCW heat exchanger of a nuclear power plant is provided.

  10. Comparisons of some scattering theories with recent scatterometer measurements. [sea roughness radar model

    Science.gov (United States)

    Fung, A. K.; Dome, G.; Moore, R. K.

    1977-01-01

    The paper compares the predictions of two different types of sea scatter theories with recent scatterometer measurements which indicate the variations of the backscattering coefficient with polarization, incident angle, wind speed, and azimuth angle. Wright's theory (1968) differs from that of Chan and Fung (1977) in two major aspects: (1) Wright uses Phillips' sea spectrum (1966) while Chan and Fung use that of Mitsuyasu and Honda, and (2) Wright uses a modified slick sea slope distribution by Cox and Munk (1954) while Chan and Fung use the slick sea slope distribution of Cox and Munk defined with respect to the plane perpendicular to the look direction. Satisfactory agreements between theory and experimental data are obtained when Chan and Fung's model is used to explain the wind and azimuthal dependence of the scattering coefficient.

  11. Design and Realization Aspects of 1-THz Cascade Backward Wave Amplifier Based on Double Corrugated Waveguide

    DEFF Research Database (Denmark)

    Paoloni, Claudio; Di Carlo, Aldo; Bouamrane, Fayçal

    2013-01-01

    The design and fabrication challenges in the first ever attempt to realize a 1-THz vacuum tube amplifier are described. Implementation of innovative solutions including a slow-wave structure in the form of a double corrugated waveguide, lateral tapered input and output couplers, deep X-ray LIGA f...

  12. Automation in tube finishing bay

    International Nuclear Information System (INIS)

    Bhatnagar, Prateek; Satyadev, B.; Raghuraman, S.; Syama Sundara Rao, B.

    1997-01-01

    Automation concept in tube finishing bay, introduced after the final pass annealing of PHWR tubes resulted in integration of number of sub-systems in synchronisation with each other to produce final cut fuel tubes of specified length, tube finish etc. The tube finishing bay which was physically segregated into four distinct areas: 1. tube spreader and stacking area, 2. I.D. sand blasting area, 3. end conditioning, wad blowing, end capping and O.D. wet grinding area, 4. tube inspection, tube cutting and stacking area has been studied

  13. CRL X-ray tube

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  14. TiO2/water Nanofluid Heat Transfer in Heat Exchanger Equipped with Double Twisted-Tape Inserts

    Science.gov (United States)

    Eiamsa-ard, S.; Ketrain, R.; Chuwattanakul, V.

    2018-05-01

    Nowadays, heat transfer enhancement plays an important role in improving efficiency of heat transfer and thermal systems for numerous areas such as heat recovery processes, chemical reactors, air-conditioning/refrigeration system, food engineering, solar air/water heater, cooling of high power electronics etc. The present work presents the experimental results of the heat transfer enhancement of TiO2/water nanofluid in a heat exchanger tube fitted with double twisted tapes. The study covered twist ratios of twisted tapes (y/w) of 1.5, 2.0, and 2.5) while the concentration of the nanofluid was kept constant at 0.05% by volume. Observations show that heat transfer, friction loss and thermal performance increase as twist ratio (y/w) decreases. The use of the nanofluid in the tube equipped with the double twisted-tapes with the smallest twist ratio (y/w = 1.5) results in the increases of heat transfer rates and friction factor up to 224.8% and 8.98 times, respectively as compared to those of water. In addition, the experimental results performed that double twisted tapes induced dual swirling-flows which played an important role in improving fluid mixing and heat transfer enhancement. It is also observed that the TiO2/water nanofluid was responsible for low pressure loss behaviors.

  15. Pediatric cuffed endotracheal tubes

    Directory of Open Access Journals (Sweden)

    Neerja Bhardwaj

    2013-01-01

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

  16. Doubled haploid production from Spanish onion (Allium cepa L.) germplasm: embryogenesis induction, plant regeneration and chromosome doubling.

    Science.gov (United States)

    Fayos, Oreto; Vallés, María P; Garcés-Claver, Ana; Mallor, Cristina; Castillo, Ana M

    2015-01-01

    The use of doubled haploids in onion breeding is limited due to the low gynogenesis efficiency of this species. Gynogenesis capacity from Spanish germplasm, including the sweet cultivar Fuentes de Ebro, the highly pungent landrace BGHZ1354 and the two Valenciana type commercial varieties Recas and Rita, was evaluated and optimized in this study. The OH-1 population, characterized by a high gynogenesis induction, was used as control. Growing conditions of the donor plants were tested with a one-step protocol and field plants produced a slightly higher percentage of embryogenesis induction than growth chamber plants. A one-step protocol was compared with a two-step protocol for embryogenesis induction. Spanish germplasm produced a 2-3 times higher percentage of embryogenesis with the two-step protocol, Recas showing the highest percentage (2.09%) and Fuentes de Ebro the lowest (0.53%). These percentages were significantly lower than those from the OH-1 population, with an average of 15% independently of the protocol used. The effect of different containers on plant regeneration was tested using both protocols. The highest percentage of acclimated plants was obtained with the two-step protocol in combination with Eco2box (70%), whereas the lowest percentage was observed with glass tubes in the two protocols (20-23%). Different amiprofos-methyl (APM) treatments were applied to embryos for chromosome doubling. A similar number of doubled haploid plants were recovered with 25 or 50 μM APM in liquid medium. However, the application of 25 μM in solid medium for 24 h produced the highest number of doubled haploid plants. Somatic regeneration from flower buds of haploid and mixoploid plants proved to be a successful approach for chromosome doubling, since diploid plants were obtained from the four regenerated lines. In this study, doubled haploid plants were produced from the four Spanish cultivars, however further improvements are needed to increase their gynogenesis

  17. Doubled haploid production from Spanish onion (Allium cepa L. germplasm: embryogenesis induction, plant regeneration and chromosome doubling

    Directory of Open Access Journals (Sweden)

    Oreto eFayos

    2015-05-01

    Full Text Available The use of doubled haploids in onion breeding is limited due to the low gynogenesis efficiency of this species. Gynogenesis capacity from Spanish germplasm, including the sweet cultivar Fuentes de Ebro, the highly pungent landrace BGHZ1354 and the two Valenciana type commercial varieties Recas and Rita, was evaluated and optimized in this study. The OH-1 population, characterized by a high gynogenesis induction, was used as control. Growing conditions of the donor plants were tested with a one-step protocol and field plants produced a slightly higher percentage of embryogenesis induction than growth chamber plants. A one-step protocol was compared with a two-step protocol for embryogenesis induction. Spanish germplasm produced a 2 to 3 times higher percentage of embryogenesis with the two-step protocol, Recas showing the highest percentage (2.09% and Fuentes de Ebro the lowest (0.53%. These percentages were significantly lower than those from the OH-1 population, with an average of 15% independently of the protocol used. The effect of different containers on plant regeneration was tested using both protocols. The highest percentage of acclimated plants was obtained with the two-step protocol in combination with Eco2box (70%, whereas the lowest percentage was observed with glass tubes in the two protocols (20-23%. Different amiprofos-methyl (APM treatments were applied to embryos for chromosome doubling. A similar number of doubled haploid plants were recovered with 25 or 50 µM APM in liquid medium. However, the application of 25 µM in solid medium for 24 h produced the highest number of doubled haploid plants. Somatic regeneration from flower buds of haploid and mixoploid plants proved to be a successful approach for chromosome doubling, since diploid plants were obtained from the 4 regenerated lines. In this study, doubled haploid plants were produced from the four Spanish cultivars, however further improvements are needed to increase their

  18. Pressure tube type research reactor

    International Nuclear Information System (INIS)

    Ueda, Hiroshi.

    1976-01-01

    Object: To prevent excessive heat generation due to radiation of a pressure tube vessel. Structure: A pressure tube encasing therein a core comprises a dual construction comprising inner and outer tubes coaxially disposed. High speed cooling water is passed through the inner tube for cooling. In addition, in the outer periphery of said outer tube there is provided a forced cooling tube disposed coaxially thereto, into which cooling fluid, for example, such as moderator or reflector is forcibly passed. This forced cooling tube has its outer periphery surrounded by the vessel into which moderator or reflector is fed. By the provision of the dual construction of the pressure tube and the forced cooling tube, the vessel may be prevented from heat generation. (Ikeda, J.)

  19. Technique employed to seal a tube leaking in a heat exchanger of the tube type by explosives with supporting means for the adjacent tubes

    International Nuclear Information System (INIS)

    Larson, G.C.

    1978-01-01

    This invention concerns the technique employed to seal a tube leaking in a heat exchanger of the tube and tube plate type by detonating metal plugs activated by an explosive and inserted in both ends of the tube. It refers in particular to an apparatus and process in which the deformation or distortion of the adjacent tubes and tube plate ties under the effect of the explosive forces is significantly reduced [fr

  20. Age Distribution of Lunar Impact-Melt Rocks in Apollo Drive-Tube 68001/2

    Science.gov (United States)

    Curran, N. M.; Bower, D. M.; Frasl, B.; Cohen, B. A.

    2018-01-01

    Apollo 16 double-drive tube 68001 /68002 provides impact and volcanic materials along a depth of approximately 60 cm in five compositional distinct units. 68001 /2 offers the potential to study distinct populations of impact melts with depth to understand how 'gardening' affects these samples. We will use unbiased major-element chemistry, mineralogy, and age to understand the impact history of Apollo 16 landing site. The study demonstrates the techniques that landed missions require to identify lithologies of interest (e.g., impact melts).

  1. Steam generator tube performance

    International Nuclear Information System (INIS)

    Tatone, O.S.; Pathania, R.S.

    1983-08-01

    A review of the performance of steam generator tubes in 110 water-cooled nuclear power reactors showed that tubes were plugged at 46 (42 percent) of the reactors. The number of tubes removed from service increased from 1900 (0.14 percent) in 1980 to 4692 (0.30 percent) in 1981. The leading causes of tube failures were stress corrosion cracking from the primary side, stress corrosion cracking (or intergranular attack) from the secondary side and pitting corrosion. The lowest incidence of corrosion-induced defects from the secondary side occurred in reactors that used all-volatile treatment since start-up. At one reactor a large number of degraded tubes were repaired by sleeving which is expected to become an important method of tube repair in the future

  2. Study on antioxidant experiment on forged steel tube sheet and tube hole for steam generator

    International Nuclear Information System (INIS)

    Zong Hai; Wang Detai; Ding Yang

    2012-01-01

    Antioxidant experiment on forged steel tube sheet and tube hole for steam generator was studied and the influence of different simulated heat treatments on the antioxidant performance of tube sheet and tube hole was made. The influence of different antioxidant methods on the size of tube hole was drawn. Furthermore, the change of size and weight of 18MnD5 forged steel tube sheet on the condition of different simulated heat treatments was also studied. The analytical results have proved reference information for the use of 18MnD5 material and for key processes of processing tube hole and wearing and expanding U-style tube. (authors)

  3. Pulsed electron beam generation with fast repetitive double pulse system

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Surender Kumar; Deb, Pankaj; Shyam, Anurag, E-mail: surender80@gmail.com [Energetics and Electromagnetics Division, Bhabha Atomic Research Centre, Visakhapatnam (India); Sharma, Archana [Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Mumbai (India)

    2014-07-01

    Longer duration high voltage pulse (∼ 100 kV, 260 ns) is generated and reported using helical pulse forming line in compact geometry. The transmission line characteristics of the helical pulse forming line are also used to develop fast repetition double pulse system with very short inter pulse interval. It overcomes the limitations caused due to circuit parameters, power supplies and load characteristics for fast repetitive high voltage pulse generation. The high voltage double pulse of 100 kV, 100 ns with an inter pulse repetition interval of 30 ns is applied across the vacuum field emission diode for pulsed electron beam generation. The electron beam is generated from cathode material by application of negative high voltage (> 100 kV) across the diode by explosive electron emission process. The vacuum field emission diode is made of 40 mm diameter graphite cathode and SS mesh anode. The anode cathode gap was 6 mm and the drift tube diameter was 10 cm. The initial experimental results of pulsed electron beam generation with fast repetitive double pulse system are reported and discussed. (author)

  4. Characterization of Friction Stir Welded Tubes by Means of Tube Bulge Test

    International Nuclear Information System (INIS)

    D'Urso, G.; Longo, M.; Giardini, C.

    2011-01-01

    Mechanical properties of friction stir welded joints are generally evaluated by means of conventional tensile test. This testing method might provide insufficient information because maximum strain obtained in tensile test before necking is small; moreover, the application of tensile test is limited when the joint path is not linear or even when the welds are executed on curved surfaces. Therefore, in some cases, it would be preferable to obtain the joints properties from other testing methods. Tube bulge test can be a valid solution for testing circumferential or longitudinal welds executed on tubular workpieces. The present work investigates the mechanical properties and the formability of friction stir welded tubes by means of tube bulge tests. The experimental campaign was performed on tubular specimens having a thickness of 3 mm and an external diameter of 40 mm, obtained starting from two semi-tubes longitudinally friction stir welded. The first step, regarding the fabrication of tubes, was performed combining a conventional forming process and friction stir welding. Sheets in Al-Mg-Si-Cu alloy AA6060 T6 were adopted for this purpose. Plates having a dimension of 225x60 mm were bent (with a bending axis parallel to the main dimension) in order to obtain semi-tubes. A particular care was devoted to the fabrication of forming devices (punch and die) in order to minimize the springback effects. Semi-tubes were then friction stir welded by means of a CNC machine tool. Some preliminary tests were carried out by varying the welding parameters, namely feed rate and rotational speed. A very simple tool having flat shoulder and cylindrical pin was used. The second step of the research was based on testing the welded tubes by means of tube bulge test. A specific equipment having axial actuators with a conical shape was adopted for this study. Some analyses were carried out on the tubes bulged up to a certain pressure level. In particular, the burst pressure and the

  5. Heat exchanger with layers of helical tubes provided with improved tube supports

    International Nuclear Information System (INIS)

    Carnoy, M.; Mathieu, B.; Renaux, C.

    1986-01-01

    The present heat exchanger comprises coaxial layers of helically wound tubes; these tubes are supported by support plates, each comprising a row of perforations through which the tubes of a same layer pass. Truncated sleeves are in compression around the tubes within the perforations and mounted on the support plates. Pins fix the plates of different layers together against transverse movement but allowing radial movement. The present invention finds an application with nuclear reactor steam generators [fr

  6. Dependence of CuO particle size and diameter of reaction tubing on tritium recovery for tritium safety operation

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Cui, E-mail: cdxohc10000@163.com [Shizuoka University, 836 Ohya, Suruga-ku Shizuoka 422-8529 (Japan); Uemura, Yuki; Yuyama, Kenta; Fujita, Hiroe; Sakurada, Shodai; Azuma, Keisuke [Shizuoka University, 836 Ohya, Suruga-ku Shizuoka 422-8529 (Japan); Taguchi, Akira; Hara, Masanori; Hatano, Yuji [University of Toyama, 3190 Gofuku, Toyama 939-8555 (Japan); Chikada, Takumi; Oya, Yasuhisa [Shizuoka University, 836 Ohya, Suruga-ku Shizuoka 422-8529 (Japan)

    2016-12-15

    Highlights: • Influence of CuO particle size and diameter of reaction tubing on the tritium recovery was evaluated. • Reaction rate constant of tritium with CuO particle has been calculated by the combination of experimental results and a simulation code. • Dependence of reaction tubing length on tritium conversion ratio has been explored. - Abstract: Usage of CuO and water bubbler is one of the conventional and convenient methods for tritium recovery. In present work, influence of CuO particle size and diameter of reaction tubing on the tritium recovery was evaluated. Reaction rate constant of tritium with CuO particle has been calculated by the combination of experimental results and a simulation code. Then, these results were applied for exploring the dependence of reaction tubing length on tritium conversion ratio. The results showed that the surface area of CuO has a great influence on the oxidation rate constant. The frequency factor of the reaction would be approximately doubled by reducing the CuO particle size from 1.0 mm to 0.2 mm. Cross section of reaction tubing mainly affected on the duration of tritium at the temperature below 600 K. Reaction tubing with length of 1 m at temperature of 600 K would be suitable for keeping the tritium conversion ratio above 99.9%. The length of reaction tubing can be reduced by using the smaller CuO particle or increasing the CuO temperature.

  7. 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.)

  8. Theory and design of heat exchanger : Double pipe and heat exchanger in abnormal condition

    International Nuclear Information System (INIS)

    Min, Ui Dong

    1996-02-01

    This book introduces theory and design of heat exchanger, which includes HTRI program, multiple tube heat exchanger external heating, theory of heat transfer, basis of design of heat exchanger, two-phase flow, condensation, boiling, material of heat exchanger, double pipe heat exchanger like hand calculation, heat exchanger in abnormal condition such as Jackets Vessel, and Coiled Vessel, design and summary of steam tracing.

  9. An in-tube radar for detecting cracks in metal tubing

    International Nuclear Information System (INIS)

    Caffey, Thurlow W. H.; Nassersharif, Bahram; Garcia, Gabe V.; Smith, Phillip R.; Jedlicka, Russell P.; Hensel, Edward C.

    2000-01-01

    A major cause of failures in heat exchangers and steam generators in nuclear power plants is degradation of the tubes within them. The tube failure is often caused by the development of cracks that begin on the outer surface of the tube and propagate both inwards and laterally. A new technique will be described for detection of defects using a continuous-wave radar device within metal tubing. The technique is 100% volumetric, and may find smaller defects, find them more rapidly, and find them less expensively than present methods. Because this project was started only recently, there is no demonstrated performance to report so far. However, the basic engineering concepts will be presented together with a description of the milestone tasks and dates

  10. Expansion lyre-shaped tube

    International Nuclear Information System (INIS)

    Andro, Jean.

    1973-01-01

    The invention relates the expansion lyre-shaped tube portions formed in dudgeoned tubular bundles between two bottom plates. An expansion lyre comprises at least two sets of tubes of unequal lengths coplanar and symmetrical with respect to the main tube axis, with connecting portions between the tubes forming said sets. The invention applies to apparatus such as heat exchangers, heaters, superheaters or breeders [fr

  11. 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

  12. Prospects for stronger calandria tubes

    International Nuclear Information System (INIS)

    Ells, C.E.; Coleman, C.E.; Hosbons, R.R.; Ibrahim, E.F.; Doubt, G.L.

    1990-12-01

    The CANDU calandria tubes, made of seam welded and annealed Zircaloy-2, have given exemplary service in-reactor. Although not designed as a system pressure containment, calandria tubes may remain intact even in the face of pressure tube rupture. One such incident at Pickering Unit 2 demonstrated the economic advantage of such an outcome, and a case can be made for increasing the probability that other calandria tubes would perform in a similar fashion. Various methods of obtaining stronger calandria tubes are available, and reviewed here. When the tubes are internally pressurized, the weld is the weak section of the tube. Increasing the oxygen concentration in the starting sheet, and thickening the weld, are promising routes to a stronger tube

  13. 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

  14. Method for shaping polyethylene tubing

    Science.gov (United States)

    Kramer, R. C.

    1981-01-01

    Method forms polyethylene plastic tubing into configurations previously only possible with metal tubing. By using polyethylene in place of copper or stain less steel tubing inlow pressure systems, fabrication costs are significantly reduced. Polyethylene tubing can be used whenever low pressure tubing is needed in oil operations, aircraft and space applications, powerplants, and testing laboratories.

  15. Next Generation TRD for CREAM Using Gas Straw Tubes and Foam Radiators

    Science.gov (United States)

    Malinin, A.; Ahn, H.S.; Fedin, O.; Ganel, O.; Han, J.H.; Kim, C.H.; Kim, K.C.; Lee, M.H.; Lutz, L.; Seo, E.S.; Walpole, P.; Wu, J.; Yoo, J.H.; Yoon, Y.S.; Zinn, S.Y.

    The Cosmic Ray Energetics And Mass (CREAM) experiment is designed to investigate the source, propagation and acceleration mechanism of high energy cosmic-ray nuclei, by directly measuring their energy and charge. Incorporating a transition radiation detector (TRD) provides an energy measurement complementary to the calorimeter, as well as additional track reconstruction capability. The next generation CREAM TRD is designed with 4 mm straw tubes to greatly improve tracking over the previous 20 mm tube design, thereby enhancing charge identification in the silicon charge detector (SCD). Plastic foam provides a weight-efficient radiator that doubles as a mechanical support for the straw layers. This design provides a compact, robust, reliable, low density detector to measure incident nucleus energy for 3 < Z < 30 nuclei in the Lorentz gamma factor range of 102-105. This paper discusses the new TRD design and the low power front end electronics used to achieve the large dynamic range required. Beam test results of a prototype TRD are also reported.

  16. 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

  17. Genetic interactions between planar cell polarity genes cause diverse neural tube defects in mice

    Directory of Open Access Journals (Sweden)

    Jennifer N. Murdoch

    2014-10-01

    Full Text Available Neural tube defects (NTDs are among the commonest and most severe forms of developmental defect, characterized by disruption of the early embryonic events of central nervous system formation. NTDs have long been known to exhibit a strong genetic dependence, yet the identity of the genetic determinants remains largely undiscovered. Initiation of neural tube closure is disrupted in mice homozygous for mutations in planar cell polarity (PCP pathway genes, providing a strong link between NTDs and PCP signaling. Recently, missense gene variants have been identified in PCP genes in humans with NTDs, although the range of phenotypes is greater than in the mouse mutants. In addition, the sequence variants detected in affected humans are heterozygous, and can often be detected in unaffected individuals. It has been suggested that interactions between multiple heterozygous gene mutations cause the NTDs in humans. To determine the phenotypes produced in double heterozygotes, we bred mice with all three pairwise combinations of Vangl2Lp, ScribCrc and Celsr1Crsh mutations, the most intensively studied PCP mutants. The majority of double-mutant embryos had open NTDs, with the range of phenotypes including anencephaly and spina bifida, therefore reflecting the defects observed in humans. Strikingly, even on a uniform genetic background, variability in the penetrance and severity of the mutant phenotypes was observed between the different double-heterozygote combinations. Phenotypically, Celsr1Crsh;Vangl2Lp;ScribCrc triply heterozygous mutants were no more severe than doubly heterozygous or singly homozygous mutants. We propose that some of the variation between double-mutant phenotypes could be attributed to the nature of the protein disruption in each allele: whereas ScribCrc is a null mutant and produces no Scrib protein, Celsr1Crsh and Vangl2Lp homozygotes both express mutant proteins, consistent with dominant effects. The variable outcomes of these genetic

  18. Intercostal drainage tube or intracardiac drainage tube?

    Science.gov (United States)

    Anitha, N; Kamath, S Ganesh; Khymdeit, Edison; Prabhu, Manjunath

    2016-01-01

    Although insertion of chest drain tubes is a common medical practice, there are risks associated with this procedure, especially when inexperienced physicians perform it. Wrong insertion of the tube has been known to cause morbidity and occasional mortality. We report a case where the left ventricle was accidentally punctured leading to near-exsanguination. This report is to highlight the need for experienced physicians to supervise the procedure and train the younger physician in the safe performance of the procedure.

  19. Longitudinal coupling impedance of step discontinuities in a circular beam tube

    International Nuclear Information System (INIS)

    Hahn, H.; Zatz, S.

    1979-01-01

    The longitudinal coupling impedance presented by a single wall discontinuity to the circulating beam in a circular accelerator or storage ring is usually analyzed by considering a developed periodic structure. However, the typical parameters are often such that it becomes adequate to treat the discontinuity as a nonperiodic problem. Using modal field matching methods, solutions were derived for the cases of a single as well as a double-step discontinuity in a circular beam tube. Numerical results are presented in this paper and the typical behavior at low frequency, at reasonance, and above cut-off is discussed

  20. Pneumatic tube-transported blood samples in lithium heparinate gel separator tubes may be more susceptible to haemolysis than blood samples in serum tubes.

    Science.gov (United States)

    Böckel-Frohnhöfer, Nicole; Hübner, Ulrich; Hummel, Björn; Geisel, Jürgen

    2014-10-01

    Pneumatic tube systems are widely used in hospitals. Advantages are high speed and rapid availability of the samples. However, the transportation by pneumatic tube promotes haemolysis. Haemolysis interferes with many spectrophotometric assays and is a common problem in clinical laboratories. The haemolysis index (HI) as a semi-quantitative representation of the level of haemolysis was compared in unpaired tube-transported and hand-delivered routine lithium heparinate plasma samples (n = 1368 and n = 837, respectively). Additionally, the HI distribution was measured in lithium heparinate plasma samples with a HI above the threshold value of 20 and in paired serum samples after transportation by pneumatic tube system. HI values above 20 can interfere with the selected assays: Creatine kinase (CK), creatine kinase-MB (CK-MB) and alanine aminotransferase (ALT) activities. These parameters were determined to demonstrate how haemolysis affects the results. 17.5% of the tube-transported plasma samples and 2.6% of the hand-delivered plasma samples had a HI above 20. The median HI in pneumatic tube-transported lithium heparinate plasma was 85 and 33 in the paired serum samples. The median HI difference between paired plasma and serum was 46. Blood samples in lithium heparinate tubes may be substantially more susceptible to haemolysis by pneumatic tube transportation than serum tube samples. Although our results cannot be universally applied to laboratories with different pneumatic tube systems, it is recommended that each laboratory evaluate carefully the degree of haemolysis after the transportation by the own pneumatic tube system and in terms of the sample type.

  1. A comparison of tape-tying versus a tube-holding device for securing endotracheal tubes in adults.

    Science.gov (United States)

    Murdoch, E; Holdgate, A

    2007-10-01

    During the transfer of intubated patients, endotracheal tube security is paramount. This study aims to compare two methods of securing an endotracheal tube in adults: tying with a cloth tape versus the Thomas Endotracheal Tube Holder (Laerdal). A manikin-based study was performed using paramedics and critical care doctors (consultants and senior trainees) as participants. Each participant was asked to secure an endotracheal tube that had been placed within the trachea of a manikin a total of six times, the first three times using tied cloth tape and the last three times using a Thomas Endotracheal Tube Holder. Following each 'fixation' and after the participant had left the room, the security of the tube was tested by applying a fixed force laterally and to the right by dropping a 1.25 kg weight a distance of 50 cm. The amount of movement of the tube with respect to the teeth was measured and recorded in millimetres. Two-hundred-and-seventy tube fixations (135 tied vs. 135 tube holder) were performed by 45 participants. The degree of tube movement was significantly higher when the tube was secured with a tie compared with when the tube holder was used (median movement 22 mm vs. 4 mm, P tube holder device minimised tube movement in a manikin model when compared with conventional tape tying. The use of this device when transporting intubated patients may reduce the risk of tube displacement though further clinical studies are warranted.

  2. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... search for current job openings visit HHS USAJobs Home >> NEI YouTube Videos >> NEI YouTube Videos: Amblyopia Listen NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration Amblyopia Animations Blindness Cataract ...

  3. Learning from YouTube [Video Book

    Science.gov (United States)

    Juhasz, Alexandra

    2011-01-01

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

  4. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... search for current job openings visit HHS USAJobs Home » NEI YouTube Videos » NEI YouTube Videos: Amblyopia Listen NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration Amblyopia Animations Blindness Cataract ...

  5. Heat transfer performance during in-tube condensation in horizontal smooth, micro-fin and herringbone tubes

    OpenAIRE

    2008-01-01

    M.Ing. An experimental investigation was conducted into the heat transfer characteristics of horizontal smooth, micro-fin and herringbone tubes during in-tube condensation. The study focused on the heat transfer coefficients of refrigerants R-22, R-134a and R-407C inside the three tubes. The herringbone tube results were compared to the smooth and micro-fin tube results. The average increase in the heat transfer coefficient when compared to the smooth tube was found to be as high as 322% w...

  6. Plugging criteria for steam generator tubes with axial cracks near tube support plates

    International Nuclear Information System (INIS)

    Mattar Neto, Miguel

    2000-01-01

    Stress corrosion cracking with intergranular attack occurs on the secondary side of steam generator (SG) tubes where impurities concentrate due to boiling under restricted flow conditions. In the most of cases, it can be called ODSCC (Outer Diameter Stress Corrosion Cracking). The typical locations are areas near support plates, in sludge piles and at top of tubesheet crevices. Though it can also occur on free spans under the relatively thin deposits that build up on the tube surfaces. ODSCC near tube plate supports have been the cause of plugging of many tubes. Thus, studies on SG tubes plugging criteria related to this degradation mechanism are presented in this paper. Th purpose is to avoid unnecessary tube plugging from either safety or reliability standpoint. Based on these studies some conclusions on the plugging criteria and on the difficulties to apply them are addressed. (author)

  7. Intercostal drainage tube or intracardiac drainage tube?

    Directory of Open Access Journals (Sweden)

    N Anitha

    2016-01-01

    Full Text Available Although insertion of chest drain tubes is a common medical practice, there are risks associated with this procedure, especially when inexperienced physicians perform it. Wrong insertion of the tube has been known to cause morbidity and occasional mortality. We report a case where the left ventricle was accidentally punctured leading to near-exsanguination. This report is to highlight the need for experienced physicians to supervise the procedure and train the younger physician in the safe performance of the procedure.

  8. Condensate subcooling near tube exit during horizontal in-tube condensation

    International Nuclear Information System (INIS)

    Hashizume, K.; Abe, N.; Ozeki, T.

    1992-01-01

    In-tube condensation is encountered in various applications for heat exchangers, such as domestic air-conditioning equipment, industrial air-cooled condensers, and moisture separator reheaters (MSRs) for nuclear power pants. Numerous research work has been conducted to predict the condensation heat transfer coefficient, and we have now enough information for thermal design of heat exchangers with horizontal in-tube condensation. Most of the research is analytical and/or experimental work in the annular or stratified flow regime, or experimental work on bulk condensation, i.e., from saturated vapor to complete condensation. On the other hand, there exist few data about the heat transfer phenomena in the very lower-quality region near the tube exit. The purpose of this paper is to clarify the condensation heat transfer phenomena near the tube exit experimentally and analytically, and to predict the degree of condensate subcooling

  9. Comparison consequences of Jackson-Pratt drain versus chest tube after coronary artery bypass grafting: A randomized controlled clinical trial.

    Science.gov (United States)

    Mirmohammad-Sadeghi, Mohsen; Pourazari, Pejman; Akbari, Mojtaba

    2017-01-01

    Chest tubes are used in every case of coronary artery bypass grafting (CABG) to evacuate shed blood from around the heart and lungs. This study was designed to assess the effective of Jackson-Pratt drain in compare with conventional chest drains after CABG. This was a randomized controlled trial that conducted on 218 patients in Chamran hospital from February to December 2016. Eligible patients were randomized in a 1:1 ratio. Jackson-Pratt drain group had 109 patients who received a chest tube insertion in the pleural space of the left lung and a Jackson-Pratt drain in mediastinum, and Chest tube drainage group had 109 patients who received double chest tube insertion in the pleural space of the left lung and the mediastinum. The incidence of pleural effusions in Jackson-Pratt drain group and chest tube group were not statistically different. The pain score at 2-h in Drain group was significantly higher than chest tube group ( P = 0.001), but the trend of pain score between groups was not significantly different ( P = 0.097). The frequency of tamponade and atrial fibrillation (AF) were significantly lower in Jackson-Pratt drain group ( P drain is equally effective for preventing cardiac tamponade, pleural effusions, and pain intensity in patients after CABG when compared with conventional chest tubes, but was significantly superior regarding efficacy to hospital and Intensive Care Unit length of stay and the incidence of AF.

  10. Microdischarges in DC accelerator tubes

    International Nuclear Information System (INIS)

    Eastham, D.A.; Thorn, R.

    1978-07-01

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

  11. The effectiveness of an endotracheal tube holder

    Directory of Open Access Journals (Sweden)

    Byung Gun Lim

    2016-01-01

    Full Text Available The security of the endotracheal tube (ETT is important in the anesthesia and intensive care settings. Recently, an ETT holder instead of an adhesive tape is frequently used to provide the fixation of the ETT. There are some studies that focused on the effectiveness of the ETT holder in preventing displacement of ETT compared to an adhesive tape (1, 2. I have experienced the use of an ETT holder (E-holder, KS medical, Bucheon, Korea in many different anesthesia settings and recognized its usefulness and convenience other than ETT security in the following specific settings.  Firstly, the ETT holder is definitely effective for patients undergoing procedures that frequently require the adjustment of ETT (or double lumen tube location including thoracic surgery. The location of double lumen tube needed for lung separation can be modified for effective ventilation during anesthetic induction or surgery, and after position changes. The tube can be easily relocated to the proper place for lung separation and effective ventilation by unlocking/relocking the button of the ETT holder under flexible bronchoscopic guidance (Fig. 1A, which can facilitate the operative procedure to be performed easily and quickly. Secondly, the ETT holder can be useful in procedures requiring the prone position (3. Especially, it is useful in all circumstances requiring the adjustment of ETT in the prone position. For instance, it is definitely useful for patients with Duchene muscular dystrophy undergoing scoliosis surgery under prone position. Adolescent patients with Duchene muscular dystrophy frequently have tracheobronchial malacia. If so, the airway pressure can be elevated due to the narrowing of the lesion of malacia when changed to the prone position (4. To overcome this problem, a reinforced ETT should be relocated so that it passes the narrowed tracheal lesion under flexible bronchoscopic guidance (Fig. 1B. However, the approach for this management is somewhat

  12. 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.

  13. Enhancement of distillate output of double basin solar still with vacuum tubes

    OpenAIRE

    Hitesh N. Panchal

    2015-01-01

    In this research paper, attempts are made to make a double basin solar still. The overall size of the lower basin used is 1006 mm × 325 mm × 380 mm and the outer basin is 1006 mm × 536 mm × 100 mm. Black granite gravel is used to increase the distillate output by reducing the quantity of brackish or saline water in both basins. Several experiments have been conducted to determine the performance of a solar still in climate conditions of Mehsana (latitude of 23°59′ and longitude of 72° 38′), G...

  14. Categorising YouTube

    Directory of Open Access Journals (Sweden)

    Thomas Mosebo Simonsen

    2011-09-01

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

  15. Lunar Lava Tube Sensing

    Science.gov (United States)

    York, Cheryl Lynn; Walden, Bryce; Billings, Thomas L.; Reeder, P. Douglas

    1992-01-01

    Large (greater than 300 m diameter) lava tube caverns appear to exist on the Moon and could provide substantial safety and cost benefits for lunar bases. Over 40 m of basalt and regolith constitute the lava tube roof and would protect both construction and operations. Constant temperatures of -20 C reduce thermal stress on structures and machines. Base designs need not incorporate heavy shielding, so lightweight materials can be used and construction can be expedited. Identification and characterization of lava tube caverns can be incorporated into current precursor lunar mission plans. Some searches can even be done from Earth. Specific recommendations for lunar lava tube search and exploration are (1) an Earth-based radar interferometer, (2) an Earth-penetrating radar (EPR) orbiter, (3) kinetic penetrators for lunar lava tube confirmation, (4) a 'Moon Bat' hovering rocket vehicle, and (5) the use of other proposed landers and orbiters to help find lunar lava tubes.

  16. X-ray tube current control

    International Nuclear Information System (INIS)

    Dupuis, W.A.; Resnick, T.A.

    1982-01-01

    A closed loop feedback system for controlling the current output of an x-ray tube. The system has circuitry for improving the transient response and stability of the x-ray tube current over a substantial nonlinear portion of the tube current production characteristic. The system includes a reference generator for applying adjustable step function reference signals representing desired tube currents. The system also includes means for instantaneous sensing of actual tube current. An error detector compares the value of actual and reference tube current and produces an error signal as a function of their difference. The system feedback loop includes amplification circuitry for controlling x-ray tube filament dc voltage to regulate tube current as a function of the error signal value. The system also includes compensation circuitry, between the reference generator and the amplification circuitry, to vary the loop gain of the feedback control system as a function of the reference magnitude

  17. Manipulation and functionalization of nano-tubes: application to boron nitride nano-tubes

    International Nuclear Information System (INIS)

    Maguer, A.

    2007-01-01

    This PhD work is divided into two parts dealing with boron nitride (BNNT) and carbon nano-tubes. The first part is about synthesis, purification and chemical functionalization of BNNT. Single-walled BNNT are synthesized by LASER ablation of a hBN target. Improving the synthesis parameters first allowed us to limit the byproducts (hBN, boric acid). A specific purification process was then developed in order to enrich the samples in nano-tubes. Purified samples were then used to develop two new chemical functionalization methods. They both involve chemical molecules that present a high affinity towards the BN network. The use of long chain-substituted quinuclidines and borazines actually allowed the solubilization of BNNT in organic media. Purification and functionalization were developed for single-walled BNNT and were successfully applied to multi-walled BNNT. Sensibility of boron to thermic neutrons finally gave birth to a study about covalent functionalization possibilities of the network. The second part of the PhD work deals with separation of carbon nano-tubes depending on their properties. Microwave irradiation of carbon nano-tubes first allowed the enrichment of initially polydisperse samples in large diameter nano-tubes. A second strategy involving selective interaction between one type of tubes and fullerene micelles was finally envisaged to selectively solubilize carbon nano-tubes with specific electronic properties. (author) [fr

  18. Experimental evaluation of emergency operating procedures on multiple steam generator tube rupture in INER integral system test facility

    International Nuclear Information System (INIS)

    Liu, T.J.; Lin, Y.M.; Lee, C.H.; Chang, C.Y.; Hong, W.T.

    1997-01-01

    The multiple steam generator tube rupture (SGTR) scenario in Westinghouse type pressurized water reactor (PWR) has been investigated at the Institute of Nuclear Energy Research (INER) Integral System Test (IIST) facility. This reduced-height and reduced-pressure test facility was designed to simulate the main features of Maanshan nuclear power plant. The SGTR test scenario assumes the double-ended break of one-, two- and six- tubes without other failures. The major operator actions follow the related symptom-oriented Emergency Operating Procedure (EOP) on the reference plant. This study focuses on the investigation of thermal-hydraulics phenomena and the adequacy of associated EOP to limit primary-to-secondary leakage. Through this study, it is found that the adequacy of current EOP in minimizing the radioactivity release demands early substantial operator involvement, especially in the multi-tubes break events. Also, the detailed mechanism of the main thermal-hydraulic phenomena during the SGTR transient are explored. (author)

  19. [Prehospital airway management of laryngeal tubes. Should the laryngeal tube S with gastric drain tube be preferred in emergency medicine?].

    Science.gov (United States)

    Dengler, V; Wilde, P; Byhahn, C; Mack, M G; Schalk, R

    2011-02-01

    Laryngeal tubes (LT) are increasingly being used for emergency airway management. This article reports on two patients in whom out-of-hospital intubation with a single-lumen LT was associated with massive pulmonary aspiration in one patient and gastric overinflation in the other. In both cases peak inspiratory pressures exceeded the LT leak pressure of approximately 35 mbar. This resulted in gastric inflation and decreased pulmonary compliance and increased inspiratory pressure further, thereby creating a vicious circle. It is therefore recommended that laryngeal tube suction (LTS) should be used in all cases of emergency airway management and a gastric drain tube be inserted through the dedicated second lumen. Apart from gastric overinflation, incorrect LT/LTS placement must be detected and immediately corrected, e.g. in cases of difficult or impossible gastric tube placement, permanent drainage of air from the gastric tube, decreasing minute ventilation or an ascending capnography curve.

  20. Vortex ring formation at the open end of a shock tube: A particle image velocimetry study

    Science.gov (United States)

    Arakeri, J. H.; Das, D.; Krothapalli, A.; Lourenco, L.

    2004-04-01

    The vortex ring generated subsequent to the diffraction of a shock wave from the open end of a shock tube is studied using particle image velocimetry. We examine the early evolution of the compressible vortex ring for three-exit shock Mach numbers, 1.1, 1.2, and 1.3. For the three cases studied, the ring formation is complete at about tUb/D=2, where t is time, Ub is fluid velocity behind shock as it exits the tube and D is tube diameter. Unlike in the case of piston generated incompressible vortex rings where the piston velocity variation with time is usually trapezoidal, in the shock-generated vortex ring case the exit fluid velocity doubles from its initial value Ub before it slowly decays to zero. At the end of the ring formation, its translation speed is observed to be about 0.7 Ub. During initial formation and propagation, a jet-like flow exists behind the vortex ring. The vortex ring detachment from the tailing jet, commonly referred to as pinch-off, is briefly discussed.

  1. Molybdenum Tube Characterization report

    Energy Technology Data Exchange (ETDEWEB)

    Beaux II, 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)

    2017-02-07

    Chemical vapor deposition (CVD) techniques have been utilized to produce free-standing molybdenum tubes with the end goal of nuclear fuel clad applications. In order to produce tubes with properties desirable for this application, deposition rates were lowered requiring long deposition durations on the order of 50 hours. Standard CVD methods as well as fluidized-bed CVD (FBCVD) methods were applied towards these objectives. Characterization of the tubes produced in this manner revealed material suitable for fuel clad applications, but lacking necessary uniformity across the length of the tubes. The production of freestanding Mo tubes that possess the desired properties across their entire length represents an engineering challenge that can be overcome in a next iteration of the deposition system.

  2. Apparatus for forming an explosively expanded tube-tube sheet joint

    International Nuclear Information System (INIS)

    Schroeder, J.W.

    1984-01-01

    The invention relates to apparatus for expanding a tube into a bore formed in a tube sheet. According to the invention, a primary explosive containing a relatively high number of grains of explosive per unit length extends within the tube coextensive with that portion of the tube to be expanded. An energy transfer cord extends between a detonator and the primary explosive and includes a relatively low number of grains of explosive per unit length which are insufficient to detonate the primary explosive. The transfer cord is covered by a sheath to contain the debris and gases associated with the explosion of the explosive therein. A booster extends between the energy transfer cord and the primary explosive and contains an explosive which can be detonated by the explosive in the energy transfer cord and can, upon exploding, in turn detonate the primary explosive. (author)

  3. Failure analysis of boiler tube

    International Nuclear Information System (INIS)

    Mehmood, K.; Siddiqui, A.R.

    2007-01-01

    Boiler tubes are energy conversion components where heat energy is used to convert water into high pressure superheated steam, which is then delivered to a turbine for electric power generation in thermal power plants or to run plant and machineries in a process or manufacturing industry. It was reported that one of the tubes of a fire-tube boiler used in a local industry had leakage after the formation of pits at the external surface of the tube. The inner side of the fire tube was working with hot flue gasses with a pressure of 10 Kg/cm/sup 2/ and temperature 225 degree C. The outside of the tube was surrounded by feed water. The purpose of this study was to determine the cause of pits developed at the external surface of the failed boiler tube sample. In the present work boiler tube samples of steel grade ASTM AI61/ASTM A192 were analyzed using metallographic analysis, chemical analysis, and mechanical testing. It was concluded that the appearance of defects on the boiler tube sample indicates cavitation type corrosion failure. Cavitation damage superficially resembled pitting, but surface appeared considerably rougher and had many closely spaced pits. (author)

  4. Neural Tube Defects

    Science.gov (United States)

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

  5. Double-modification of lectin using two distinct chemistries for fluorescent ratiometric sensing and imaging saccharides in test tube or in cell.

    Science.gov (United States)

    Nakata, Eiji; Koshi, Yoichiro; Koga, Erina; Katayama, Yoshiki; Hamachi, Itaru

    2005-09-28

    The site-selective incorporation of two different fluorophores into a naturally occurring protein (lectin, a sugar-binding protein) has been successfully carried out using two distinct orthogonal chemical methods. By post-photoaffinity labeling modification, Con A, a glucose- and mannose-selective lectin, was modified with fluorescein in the proximity of the sugar binding site (Tyr100 site), and the controlled acylation reaction provided the site-selective attachment of coumarin at Lys114. In this doubly modified Con A, the fluorescein emission changed upon the binding to the corresponding sugars, such as the glucose or mannose derivatives, whereas the coumarin emission was constant. Thus, the doubly modified Con A fluorescently sensed the glucose- and mannose-rich saccharides in a ratiometric manner while retaining the natural binding selectivity and affinity, regardless of the double modification. On the benefit of the ratiometric fluorescent analysis using two distinct probes, the sugar trimming process of a glycoprotein can be precisely monitored by the engineered Con A. Furthermore, the doubly modified Con A can be used not only for the convenient fluorescent imaging of saccharides localized on a cell surface, such as the MCF-7, a breast cancer cell having rich high-mannose branch, but also for the ratiometric fluorescent sensing of the glucose concentration inside HepG2 cells. These results demonstrated that the semisynthetic lectin modified doubly by two distinct chemistries is superior to the singly modified one in function, and thus, it may be potentially useful in cell, as well as in test tube.

  6. Condensing heat transfer characteristics of hydrocarbon refrigerants in 9.52 and 12.7 mm smooth tube

    Science.gov (United States)

    Yoon, Jung-In; Lee, Ho-Saeng; Lee, Kwang-Bae; Kim, Jae-Dol; Bansal, Pradeep

    2005-12-01

    Experimental results for heat transfer characteristic and pressure gradients of hydrocarbon (HC) refrigerants and R-22 during condensing inside horizontal double pipe heat exchangers are presented. The test sections which have one tube diameter of 12.70 mm with 0.86 mm wall thickness, another tube diameter of 9.52 mm with 0.76 mm wall thickness are used for this investigation. The local condensing heat transfer coefficients of HC refrigerants were higher than that of R-22. The average condensing heat transfer coefficient increased with the increase of the mass flux. It showed the higher values in HC refrigerants than R-22. Comparing the heat transfer coefficient of experimental results with that of other correlations, the presented results had a good agreement with most of the Cavallini’s correlations.

  7. Importance of crevices formed between tubes and tube plate for the operational behaviour of heat exchangers

    International Nuclear Information System (INIS)

    Achten, N.; Herbsleb, G.; Wieling, N.

    1986-01-01

    It must be guaranteed by construction and manufacture of heat exchangers that primary and secondary medium are completely separated from each other. When this requirement is fullfilled, the operational use of heat exchangers can be impaired by corrosion reactions within the crevice formed between tube and tube plate which may result in corrosion damage. The various techniques which are in use to connect tubes and tube plate and which are described in the present report, must be valued with respect to the tightness of the connection as well as to the formation of crevices between tubes and tube plate. Corrosion resistant copperbase alloys and stainless steels are the most important materials which are in use for the construction of heat exchangers. The mechanisms of crevice corrosion with unalloyed and low alloy carbon steels, stainless steels, and mixed connections between tube and tube plate with these materials are described in detail. Crevice corrosion may be caused also by the formation of galvanic cells between materials of differing electrochemical response. Furthermore, the concentration of aggressive media in crevices between tubes and tube plate can lead to corrosion damage of heat exchanger tubes. For the service operation of heat exchangers without any hazard of corrosion damage in crevices between tubes and tube plate, such crevices must be avoided by proper construction and manufacture. As a model for suitable measures to avoid crevices, the manufacture of steam generators for PWR's is described. (orig.) [de

  8. Double-contrast examination of the gastric antrum without Duodenal superposition

    International Nuclear Information System (INIS)

    Treugut, H.; Isper, J.

    1980-01-01

    By using a modified technique of double-contrast examination of the stomach it was possible in 75% to perform a study without superposition of the duodenum and jejunum on the distal stomach compared to 36% with the usual method. In this technique a small amount (50 ml) of Barium-suspension is given to the patient in left decubitus position by a straw or gastric tube after antiperistaltic medication. There was no difference in the quality of mucosa-coating compared to the technique using higher volumes of Barium. (orig.) [de

  9. A Study on the Profile Change Measurement of Steam Generator Tubes with Tube Expansion Methods

    International Nuclear Information System (INIS)

    Kim, Young Kyu; Song Myung Ho; Choi, Myung Sik

    2011-01-01

    Steam generator tubes for nuclear power plants contain the local shape transitions on their inner or outer surface such as dent, bulge, over-expansion, eccentricity, deflection, and so on by the application of physical force during the tube manufacturing and steam generator assembling and by the sludge (that is, corrosion products) produced during the plant operation. The structural integrity of tubes will be degraded by generating the corrosive crack at that location. The profilometry using the traditional bobbin probes which are currently applied for measuring the profile change of tubes gives us basic information such as axial locations and average magnitudes of deformations. However, the three-dimensional quantitative evaluation on circumferential locations, distributional angle, and size of deformations will have to be conducted to understand the effects of residual stresses increased by local deformations on corrosive cracking of tubes. Steam generator tubes of Korean standard nuclear power plants expanded within their tube-sheets by the explosive expansion method and suffered from corrosive cracks in the early stage of power operation. Thus, local deformations of steam generator tubes at the top of tube-sheet were measured with an advanced rotating probe and a laser profiling system for the two cases where the tubes expanded by the explosive expansion method and hydraulic expansion. Also, the trends of eccentricity, deflection, and over-expansion of tubes were evaluated. The advanced eddy current profilometry was confirmed to provide accurate information of local deformations compared with laser profilometry

  10. A comparison of R-22, R-134a, R-410a, and R-407c condensation performance in smooth and enhanced tubes: Part 1, Heat transfer

    Energy Technology Data Exchange (ETDEWEB)

    Eckels, S J; Tesene, B A

    1999-07-01

    Local and average heat transfer coefficients during condensation are reported for R-22, R-134a, R-410a, and R-407c in one smooth tube and three enhanced surface tubes. The test tubes included a 3/8 inch outer diameter smooth tube, a 3/8 inch outer diameter microfin tube, a 5/16 inch outer diameter microfin tube, and a 5/8 inch outer diameter microfin tube. The local and average heat transfer coefficients were measured over a mass flux range of 92,100 lb/ft{sup 2}{center_dot}h to 442,200 lb/ft{sup 2}{center_dot}h and at saturation temperatures of 104 F and 122 F. A comparison of the performance of the different refrigerants reveals that R-134a has the highest heat transfer performance followed by R-22 and R-410a, which have similar performances. In general, R-407c had the lowest performance of the refrigerants tested. The microfin tube more than doubles the heat transfer coefficient compared to the smooth tube for all refrigerants at the low mass fluxes, but only increases the heat transfer coefficients by 50% at the highest mass flux tested. The measured heat transfer coefficients are also compared with a number of correlations for condensation.

  11. Procedure and device for extracting the end of a tube inserted into a hole in a tube plate

    International Nuclear Information System (INIS)

    1980-01-01

    When constructing heat exchangers and steam generators, particularly in the construction of steam generators for nuclear power stations, many small diameter tubes have to be secured into a very thick tube plate for instance 600 mm thick. This crimping or expanding of the tube is generally performed by rolling the internal surface of the tube inside a hole drilled right through the tube plate and slightly greater in diameter than the external diameter of the tube before the tube is rolled. To check the tubes for defects, it is necessary to extract certain tubes from the tube plate in order to move the tube to a testing and inspection point and examine the part of it that was secured in the plate hole. The invention concerns the uncrimping of these tubes [fr

  12. Radiation-resistant camera tube

    International Nuclear Information System (INIS)

    Kuwahata, Takao; Manabe, Sohei; Makishima, Yasuhiro

    1982-01-01

    It was a long time ago that Toshiba launched on manufacturing black-and-white radiation-resistant camera tubes employing nonbrowning face-plate glass for ITV cameras used in nuclear power plants. Now in compliance with the increasing demand in nuclear power field, the Company is at grips with the development of radiation-resistant single color-camera tubes incorporating a color-stripe filter for color ITV cameras used under radiation environment. Herein represented are the results of experiments on characteristics of materials for single color-camera tubes and prospects for commercialization of the tubes. (author)

  13. Jose Cabrera (Zorita) tube examination

    International Nuclear Information System (INIS)

    Kuchirka, P.J.

    1986-01-01

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

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

    International Nuclear Information System (INIS)

    Shin, Y.S.; Jendrzejczyk, J.A.; Wambsganss, M.W.

    1977-01-01

    To avoid detrimental tube vibration in heat exchangers, resonant conditions and instabilitites must be avoided, and/or peak dynamic amplitudes must not exceed allowable limits. In attempting a theoretical analysis, questions arise as to the effects of tube/support interaction on tube vibrational characteristics (i.e. resonant frequencies, modes, damping) and response amplitude. As a part of ANL's Flow-Induced Vibration Program in support of the Clinch River Breeder Reactor Plant (CRBRP) steam generator design activity, tube/support interaction experiments are being performed not only to gain the insight into the dynamic behavior of CRBRP steam generator tubes, but also to provide the basis for developing design guidance. Test results were compared with anaytical results based on multispan tube with 'knife-edge' supports at the support locations. (Auth.)

  15. Twin-tubes: 3D tracking based on the ATLAS muon drift tubes

    International Nuclear Information System (INIS)

    Woudstra, M.; Bobbink, G.J.; Eldik, N. van; Graaf, H. van der; Kluit, P.; Koutsman, A.; Limper, M.; Linde, F.; Massaro, G.; Snuverink, J.; Vreeswijk, M.; Groenstege, H.; Koopstra, J.; Mos, S.; Rewiersma, P.; Timmermans, C.; Dijkema, J.

    2006-01-01

    The Monitored Drift Tubes (MDTs) of the ATLAS Muon Spectrometer have been paired to form so-called twin-tubes to measure the coordinate which runs along the wire direction. This modification endows the MDTs with full 3D track reconstruction using specially designed electronic boards. The performance of the twin-tubes has been measured for an equipped MDT chamber at the ATLAS Muon Cosmic Ray Test Stand at NIKHEF. The efficiency of a twin-tube has been determined to be 99.8%, and the measured resolution 17 cm per hit. By equipping one multilayer consisting of three layers and combining the measurements a resolution of 10 cm has been obtained

  16. 78 FR 60844 - Wooden Bedroom Furniture From the People's Republic of China: Partial Rescission of Antidumping...

    Science.gov (United States)

    2013-10-02

    ... Furniture Co., Ltd. Dorbest Ltd., Rui Feng Woodwork Co., Ltd. Aka Rui Feng Woodwork (Dongguan) Co., Ltd., Rui Feng Lumber Development Co., Ltd. Aka Rui Feng Lumber Development (Shenzhen) Co., Ltd., Fine... Fung Wooden Factory, Sun Fung Co., Shin Feng Furniture Co., Ltd., Stupendous International Co., Ltd...

  17. Optimisation of a double-centrifugation method for preparation of canine platelet-rich plasma.

    Science.gov (United States)

    Shin, Hyeok-Soo; Woo, Heung-Myong; Kang, Byung-Jae

    2017-06-26

    Platelet-rich plasma (PRP) has been expected for regenerative medicine because of its growth factors. However, there is considerable variability in the recovery and yield of platelets and the concentration of growth factors in PRP preparations. The aim of this study was to identify optimal relative centrifugal force and spin time for the preparation of PRP from canine blood using a double-centrifugation tube method. Whole blood samples were collected in citrate blood collection tubes from 12 healthy beagles. For the first centrifugation step, 10 different run conditions were compared to determine which condition produced optimal recovery of platelets. Once the optimal condition was identified, platelet-containing plasma prepared using that condition was subjected to a second centrifugation to pellet platelets. For the second centrifugation, 12 different run conditions were compared to identify the centrifugal force and spin time to produce maximal pellet recovery and concentration increase. Growth factor levels were estimated by using ELISA to measure platelet-derived growth factor-BB (PDGF-BB) concentrations in optimised CaCl 2 -activated platelet fractions. The highest platelet recovery rate and yield were obtained by first centrifuging whole blood at 1000 g for 5 min and then centrifuging the recovered platelet-enriched plasma at 1500 g for 15 min. This protocol recovered 80% of platelets from whole blood and increased platelet concentration six-fold and produced the highest concentration of PDGF-BB in activated fractions. We have described an optimised double-centrifugation tube method for the preparation of PRP from canine blood. This optimised method does not require particularly expensive equipment or high technical ability and can readily be carried out in a veterinary clinical setting.

  18. Liquid-Nitrogen Test for Blocked Tubes

    Science.gov (United States)

    Wagner, W. R.

    1984-01-01

    Nondestructive test identifies obstructed tube in array of parallel tubes. Trickle of liquid nitrogen allowed to flow through tube array until array accumulates substantial formation of frost from moisture in air. Flow stopped and warm air introduced into inlet manifold to heat tubes in array. Tubes still frosted after others defrosted identified as obstructed tubes. Applications include inspection of flow systems having parallel legs.

  19. Modeling of second-harmonic generation of circumferential guided wave propagation in a composite circular tube

    Science.gov (United States)

    Li, Mingliang; Deng, Mingxi; Gao, Guangjian; Xiang, Yanxun

    2018-05-01

    This paper investigated modeling of second-harmonic generation (SHG) of circumferential guided wave (CGW) propagation in a composite circular tube, and then analyzed the influences of interfacial properties on the SHG effect of primary CGW. Here the effect of SHG of primary CGW propagation is treated as a second-order perturbation to its linear wave response. Due to the convective nonlinearity and the inherent elastic nonlinearity of material, there are second-order bulk driving forces and surface/interface driving stresses in the interior and at the surface/interface of a composite circular tube, when a primary CGW mode propagates along its circumference. Based on the approach of modal expansion analysis for waveguide excitation, the said second-order driving forces/stresses are regarded as the excitation sources to generate a series of double-frequency CGW modes that constitute the second-harmonic field of the primary CGW propagation. It is found that the modal expansion coefficient of each double-frequency CGW mode is closely related to the interfacial stiffness constants that are used to describe the interfacial properties between the inner and outer circular parts of the composite tube. Furthermore, changes in the interfacial stiffness constants essentially influence the dispersion relation of CGW propagation. This will remarkably affect the efficiency of cumulative SHG of primary CGW propagation. Some finite element simulations have been implemented of response characteristics of cumulative SHG to the interfacial properties. Both the theoretical analyses and numerical simulations indicate that the effect of cumulative SHG is found to be much more sensitive to changes in the interfacial properties than primary CGW propagation. The potential of using the effect of cumulative SHG by primary CGW propagation to characterize a minor change in the interfacial properties is considered.

  20. Development and Technology Transfer of the Syncro Blue Tube (Gabriel) Magnetically Guided Feeding Tube

    Science.gov (United States)

    2017-06-01

    suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188...the tube to the 110 cm mark. At the 110 cm mark, secure the tube with medical tape and remove the stylet completely allowing enough tube slack ...and it provides slack that allows tube to advance distally by the effect of natural peristalsis on the bolus-sized balloon. Results: Most feeding

  1. X-ray tubes

    International Nuclear Information System (INIS)

    Young, R.W.

    1979-01-01

    A form of x-ray tube is described which provides satisfactory focussing of the electron beam when the beam extends for several feet from gun to target. Such a tube can be used for computerised tomographic scanning. (UK)

  2. X-ray tube

    International Nuclear Information System (INIS)

    Webley, R.S.

    1975-01-01

    The object of the invention described is to provide an X-ray tube providing a scanned X-ray output which does not require a scanned electron beam. This is obtained by an X-ray tube including an anode which is rotatable about an axis, and a source of a beam of energy, for example an electron beam, arranged to impinge on a surface of the anode to generate X-radiation substantially at the region of incidence on the anode surface. The anode is rotatable about the axis to move the region of incidence over the surface. The anode is so shaped that the rotation causes the region of incidence to move in a predetermined manner relative to fixed parts of the tube so that the generated X-radiation is scanned in a predetermined manner relative to the tube. (UK)

  3. Pump element for a tube pump

    DEFF Research Database (Denmark)

    2011-01-01

    The invention relates to a tube pump comprising a tube and a pump element inserted in the tube, where the pump element comprises a rod element and a first and a second non-return valve member positioned a distance apart on the rod element. The valve members are oriented in the same direction...... relative to the rod element so as to allow for a fluid flow in the tube through the first valve member, along the rod element, and through the second valve member. The tube comprises an at least partly flexible tube portion between the valve members such that a repeated deformation of the flexible tube...... portion acts to alternately close and open the valve members thereby generating a fluid flow through the tube. The invention further relates to a pump element comprising at least two non-return valve members connected by a rod element, and for insertion in an at least partly flexible tube in such tube...

  4. Ultrasonic measurement of gap between calandria tube and liquid injection shutdown system tube in PHWR

    International Nuclear Information System (INIS)

    Kim, Tae Ryong; Sohn, Seok Man; Lee, Jun Shin; Lee, Sun Ki; Lee, Jong Po

    2001-01-01

    Sag of CT or liquid injection shutdown system tubes in pressurized heavy water reactor is known to occur due to irradiation creep and growth during plant operation. When the sag of CT is big enough, the CT tube possibly comes in contact with liquid injection shutdown system tube (LIN) crossing beneath the CT, which subsequently may prevent the safe operation. It is therefore necessary to check the gap between the two tubes in order to confirm no contacts when using a proper measure periodically during the plant life. An ultrasonic gap measuring probe assembly which can be fed through viewing port installed on the calandria was developed and utilized to measure the sags of both tubes in a pressurized heavy water reactor in Korea. It was found that the centerlines of CT and LIN can be precisely detected by ultrasonic wave. The gaps between two tubes were easily obtained from the relative distance of the measured centerline elevations of the tubes. But the measured gap data observed at the viewing port were actually not the data at the crossing point of CT and LIN. To get the actual gap between two tubes, mathematical modeling for the deflection curves of two tubes was used. The sags of CT and LIN tubes were also obtained by comparison of the present centerlines with the initial elevations at the beginning of plant operation. The gaps between two tubes in the unmeasurable regions were calculated based on the measurement data and the channel power distribution

  5. Tubing misconnections: normalization of deviance.

    Science.gov (United States)

    Simmons, Debora; Symes, Lene; Guenter, Peggi; Graves, Krisanne

    2011-06-01

    Accidental connection of an enteral system to an intravenous (IV) system frequently results in the death of the patient. Misconnections are commonly attributed to the presence of universal connectors found in the majority of patient care tubing systems. Universal connectors allow for tubing misconnections between physiologically incompatible systems. The purpose of this review of case studies of tubing misconnections and of current expert recommendations for safe tubing connections was to answer the following questions: In tubing connections that have the potential for misconnections between enteral and IV tubing, what are the threats to safety? What are patient outcomes following misconnections between enteral and IV tubing? What are the current recommendations for preventing misconnections between enteral and IV tubing? Following an extensive literature search and guided by 2 models of threats and errors, the authors analyzed case studies and expert opinions to identify technical, organizational, and human errors; patient-related threats; patient outcomes; and recommendations. A total of 116 case studies were found in 34 publications. Each involved misconnections of tubes carrying feedings, intended for enteral routes, to IV lines. Overwhelmingly, the recommendations were for redesign to eliminate universal connectors and prevent misconnections. Other recommendations were made, but the analysis indicates they would not prevent all misconnections. This review of the published case studies and current expert recommendations supports a redesign of connectors to ensure incompatibility between enteral and IV systems. Despite the cumulative evidence, little progress has been made to safeguard patients from tubing misconnections.

  6. Resolution of lava tubes with ground penetrating radar: preliminary results from the TubeX project

    Science.gov (United States)

    Esmaeili, S.; Kruse, S.; Garry, W. B.; Whelley, P.; Young, K.; Jazayeri, S.; Bell, E.; Paylor, R.

    2017-12-01

    As early as the mid 1970's it was postulated that planetary tubes or caves on other planetary bodies (i.e., the Moon or Mars) could provide safe havens for human crews, protect life and shield equipment from harmful radiation, rapidly fluctuating surface temperatures, and even meteorite impacts. What is not clear, however, are the exploration methods necessary to evaluate a potential tube-rich environment to locate suitable tubes suitable for human habitation. We seek to address this knowledge gap using a suite of instruments to detect and document tubes in a terrestrial analog study at Lava Beds National Monument, California, USA. Here we describe the results of ground penetrating radar (GPR) profiles and light detection and ranging (LiDAR) scans. Surveys were conducted from the surface and within four lava tubes (Hercules Leg, Skull, Valentine and, Indian Well Caves) with varying flow composition, shape, and complexity. Results are shown across segments of these tubes where the tubes are 10 m in height and the ceilings are 1 - 10 m below the surface. The GPR profiles over the tubes are, as expected, complex, due to scattering from fractures in roof material and three-dimensional heterogeneities. Point clouds derived from the LiDAR scans of both the interior and exterior of the lava tubes provide precise positioning of the tube geometry and depth of the ceiling and floor with respect to the surface topography. GPR profiles over LiDAR-mapped tube cross-sections are presented and compared against synthetic models of radar response to the measured geometry. This comparison will help to better understand the origins of characteristic features in the radar profiles. We seek to identify the optimal data processing and migration approaches to aid lava tube exploration of planetary surfaces.

  7. The effect of tube rupture location on the consequences of multiple steam generator tube rupture event

    International Nuclear Information System (INIS)

    Jeong, Ji Hwan; Kweon, Young Chul

    2002-01-01

    A multiple steam generator tube rupture (MSGTR) event has never occurred in the commercial operation of nuclear reactors while single steam generator tube rupture (SGTR) events are reported to occur every 2 years. As there has been no occurrence of a MSGTR event, the understanding of transients and consequences of this event is very limited. In this study, a postulated MSGTR event in an advanced power reactor 1400 (APR 1400) is analyzed using the thermal-hydraulic system code, MARS1.4. The APR 1400 is a two-loop, 3893 MWt, PWR proposed to be built in 2010. The present study aims to understand the effects of rupture location in heat transfer tubes following a MSGTR event. The effects of five tube rupture locations are compared with each other. The comparison shows that the response of APR1400 allows the shortest time for operator action following a tube rupture in the vicinity of the hot-leg side tube sheet and allows the longest time following a tube rupture at the tube top. The MSSV lift time for rupture at the tube-top is evaluated as 24.5% larger than that for rupture at the hot-leg side tube sheet

  8. Experimental study of tube/support impact forces in multi-span PWR steam generator tubes

    International Nuclear Information System (INIS)

    Axisa, F.; Desseaux, A.; Gibert, R.J.

    1984-12-01

    The vibro-impact response of a straight part of a steam generator tube is investigated experimentally and using numerical simulation with the aim to relate tube overall dynamics with excitation and tube-support clearance. Configuration studied here corresponds to the tube being excited in only one direction at its first resonance presenting an antinode of vibration at the impacted support. Tests show namely that midspan displacement of tube is almost proportional to excitation level and clearance. Impact forces averaged over a cycle of vibration are almost proportional to excitation and poorly dependent on clearance. Results of numerical simulation are in fairly good agreement with test results

  9. YouTube and 'psychiatry'.

    Science.gov (United States)

    Gordon, Robert; Miller, John; Collins, Noel

    2015-12-01

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

  10. YouTube as an information source for pediatric adenotonsillectomy and ear tube surgery.

    Science.gov (United States)

    Sorensen, Jeffrey A; Pusz, Max D; Brietzke, Scott E

    2014-01-01

    Assess the overall quality of information on adenotonsillectomy and ear tube surgery presented on YouTube (www.youtube.com) from the perspective of a parent or patient searching for information on surgery. The YouTube website was systematically searched on select dates with a formal search strategy to identify videos pertaining to pediatric adenotonsillectomy and ear tube surgery. Only videos with at least 5 (ear tube surgery) or 10 (adenotonsillectomy) views per day were included. Each video was viewed and scored by two independent scorers. Videos were categorized by goal and scored for video/audio quality, accuracy, comprehensiveness, and procedure-specific content. Cross-sectional study. Public domain website. Fifty-five videos were scored for adenotonsillectomy and forty-seven for ear tube surgery. The most common category was educational (65.3%) followed by testimonial (28.4%), and news program (9.8%). Testimonials were more common for adenotonsillectomy than ear tube surgery (41.8% vs. 12.8%, p=0.001). Testimonials had a significantly lower mean accuracy (2.23 vs. 2.62, p=0.02), comprehensiveness (1.71 vs. 2.22, p=0.007), and TA specific content (0.64 vs. 1.69, p=0.001) score than educational type videos. Only six videos (5.9%) received high scores in both video/audio quality and accuracy/comprehensiveness of content. There was no significant association between the accuracy and comprehensive score and views, posted "likes", posted "dislikes", and likes/dislikes ratio. There was an association between "likes" and mean video quality (Spearman's rho=0.262, p=0.008). Parents/patients searching YouTube for information on pediatric adenotonsillectomy and ear tube surgery will generally encounter low quality information with testimonials being common but of significantly lower quality. Viewer perceived quality ("likes") did not correlate to formally scored content quality. Published by Elsevier Ireland Ltd.

  11. On the anisotropy of in-reactor creep of Zr-2.5Nb tubes

    International Nuclear Information System (INIS)

    Causey, A.R.; Holt, R.A.

    1993-06-01

    Creep specimens made from cold-worked Zr-2.5Nb tubes, fabricated with two different microstructures and crystallographic textures, were irradiated in the Osiris reactor in France in a fast-neutron flux of about 1.8 x 10 18 n.m -2 .s -1 , E > MeV, at 553 and 585 K. The hoop stresses from internal Fluences, up to 4 x 10 25 n.m -2 , more than double those achieved an any other creep test on cold-worked Zr-2.5Nb in which both axial and transverse strain were measured. Creep rates were obtained from strain versus fluence plots, and creep compliances were obtained from plots of the strain rates against hoop stress for each material at each temperature. The ratio of creep rates at 583 K to those at 553 K was ∼ 1.36, a little higher than that extrapolated from stress relaxation results at temperatures between 523 and 568 K. The ratio of the biaxial creep compliance in the axial direction to that in the transverse directions is different for the two test materials: 0.0 to -0.1 for the fuel sheathing texture and 0.5 to 0.6 for the pressure tube texture. The results were analysed using a self-consistent model developed to account for the contributions to the creep anisotropy of the three microstructure parameters involved and to account for the grain interaction effects. The model, which was normalized to test reactor and power reactor creep data for cold-worked Zr-2.5Nb tubes, predicted the ratio of the creep compliancies to be -0.26 and 0.63, respectively. Thus the creep anisotropy of Zr-2.5Nb tubes with pressure-tube-like crystallographic texture can be adequately predicted. (author). 18 refs., 4 tabs., 13 figs

  12. Development of heat treated Zr-2.5% Nb alloy tubes for pressure tubes

    International Nuclear Information System (INIS)

    Saibaba, N.; Jha, S.K.; Tonpe, S.

    2011-01-01

    Zr-2.5% Nb alloy is the candidate material for pressure tubes of Pressurized Heavy Water Reactors (PHWR), and are manufactured in cold working condition while heat treated pressure tubes are used in RBMK and FUGEN type of reactors. The diametral creep of these tubes is the life limiting factor. This paper presents the extensive work carried out for the optimization of process parameters to manufacture heat treated Zr-2.5% Nb pressure tubes. Extensive dilactometry study was carried out to establish the transus temperature for the alloy and the effect of soaking temperature and cooling rate on the microstructure was characterized. On the basis of the study, water quenching (at 883 deg C) in the a b region with 20-25% primary a phase was selected, further cold worked, aged and finally autoclaved. Mechanical properties of the finished tubes were found to be comparable to the cold worked route. Large number of full sized tubes of about 700 - 800 mm long was produced to establish the repeatability. (author)

  13. Mechanical properties of Zr-2.5Nb pressure tube material manufactured employing forging routes for PHWR700 - Part 1: tensile behavior

    International Nuclear Information System (INIS)

    Bind, A.K.; Singh, R.N.; Sunil, Saurav; Chakravartty, J.K.; Ghosh, Agnish; Dhandharia, Priyesh; More, Nitin S.; Vijayakumar, S.; Chhatre, A.G.

    2012-01-01

    Tensile properties of Zr-2.5Nb alloy tubes produced employing forging to break the cast structure were evaluated by carrying out uni-axial tension test at temperatures between 25 and 325 degC and under strain-rate of 1.075 x 10 -4 /s for both longitudinal and transverse specimens. Both strength and elongation values were comparable for the samples obtained from front and back end of the tube. Transverse samples showed higher strength and lower uniform elongation values as compared to longitudinal samples. The yield strength of double forged material at 25 degC is higher than the PHWR700 specification of a maximum value of 586 MPa. (author)

  14. Comparison consequences of Jackson-Pratt drain versus chest tube after coronary artery bypass grafting: A randomized controlled clinical trial

    Directory of Open Access Journals (Sweden)

    Mohsen Mirmohammad-Sadeghi

    2017-01-01

    Full Text Available Background: Chest tubes are used in every case of coronary artery bypass grafting (CABG to evacuate shed blood from around the heart and lungs. This study was designed to assess the effective of Jackson-Pratt drain in compare with conventional chest drains after CABG. Materials and Methods: This was a randomized controlled trial that conducted on 218 patients in Chamran hospital from February to December 2016. Eligible patients were randomized in a 1:1 ratio. Jackson-Pratt drain group had 109 patients who received a chest tube insertion in the pleural space of the left lung and a Jackson-Pratt drain in mediastinum, and Chest tube drainage group had 109 patients who received double chest tube insertion in the pleural space of the left lung and the mediastinum. Results: The incidence of pleural effusions in Jackson-Pratt drain group and chest tube group were not statistically different. The pain score at 2-h in Drain group was significantly higher than chest tube group (P = 0.001, but the trend of pain score between groups was not significantly different (P = 0.097. The frequency of tamponade and atrial fibrillation (AF were significantly lower in Jackson-Pratt drain group (P < 0.05. Conclusion: The Jackson-Pratt drain is equally effective for preventing cardiac tamponade, pleural effusions, and pain intensity in patients after CABG when compared with conventional chest tubes, but was significantly superior regarding efficacy to hospital and Intensive Care Unit length of stay and the incidence of AF.

  15. An investigation on SA 213-Tube to SA 387-Tube plate using friction welding process

    Energy Technology Data Exchange (ETDEWEB)

    Rajan, S. Pandia; Kumaraswamidhas, L. A. [Indian Institute of Technology, Jharkhand (India); Kumaran, S. Senthil [RVS School of Engineering and Technology, Tamil Nadu (India); Muthukumaran, S. [National Institute of Technology, Tamil Nadu (India)

    2016-01-15

    Friction welding of tube to tube plate using an external tool (FWTPET) is a relatively newer solid state welding process used for joining tube to tube plate of either similar or dissimilar materials with enhanced mechanical and metallurgical properties. In the present study, FWTPET has been used to weld SA 213 (Grade T12) tube with SA 387 (Grade 22) tube plate. The welded samples are found to have satisfactory joint strength and the Energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD) study showed that inter metallic compound is absent in the weld zone. The different weld joints have been identified and the phase composition is found using EDX and XRD. Microstructures have been analyzed using optical and Scanning electron microscopy (SEM). The mechanical properties such as hardness, compressive shear strength and peel test for different weld conditions are studied and the hardness survey revealed that there is increase in hardness at the weld interface due to grain refinement. The corrosion behavior for different weld conditions have been analyzed and the weld zone is found to have better corrosion resistance due to the influence of the grain refinement after FWTPET welding process. Hence, the present investigation is carried out to study the behavior of friction welded dissimilar joints of SA 213 tube and SA 387 tube plate joints and the results are presented. The present study confirms that a high quality tube to tube plate joint can be achieved using FWTPET process at 1120 rpm.

  16. Analysis of a thermal energy storage system for air cooling–heating application through cylindrical tube

    International Nuclear Information System (INIS)

    Anisur, M.R.; Kibria, M.A.; Mahfuz, M.H.; Saidur, R.; Metselaar, I.H.S.C.

    2013-01-01

    Highlights: • Some design parameters of TES system for air cooling–heating application are studied. • Allowable inner radius and thickness of the tube for air flow should be considered. • Better COP is observed by decreasing the PCM container diameter. - Abstract: In order to reduce building energy consumption, thermal energy storage (TES) system has been explored as an alternative solution for air cooling–heating application. Different types of phase change materials (PCMs) along with the different geometries of TES system have been investigated for this application. In this work, a theoretical model was used to analyse the TES system for air cooling–heating application. The heat transfer phenomena in a phase change material (PCM) outside a double wall circular tube with heat transfer fluid (HTF) as air inside the tube were studied. Potassium fluoride tetrahydrate was used as a PCM for the TES system. Laminar forced convection with varying wall temperature was considered to analyse this system. Here, some important design parameters like inner radius and thickness of the tube for HTF flow were also investigated. It was found that an optimum inner radius and thickness of the tube should be considered to design a TES system. Since, significant change in outlet air temperature from the system was observed for reducing inner radius and increasing the thickness of the tube. The coefficients of performances (COPs) for cooling were found 8.79 and 7.20 for 15 mm and 25 mm inner radiuses of the PCM container respectively. Hence, the system can be optimized by reducing the volume of the PCM container. Furthermore, better COP was observed for higher inlet air temperature while the outlet air temperature was almost identical

  17. A double-blind, placebo-controlled clinical trial of the effect of chlorpheniramine on the response of the nasal airway, middle ear and eustachian tube to provocative rhinovirus challenge.

    Science.gov (United States)

    Doyle, W J; McBride, T P; Skoner, D P; Maddern, B R; Gwaltney, J M; Uhrin, M

    1988-03-01

    This paper presents the results of a randomized, double-blind, placebo-controlled study of the efficacy of chlorpheniramine in relieving the symptoms and attenuating the pathophysiologic correlates of a rhinovirus "common cold." Forty healthy, adult, nonatopic subjects were randomly assigned to one of two treatment groups: active drug and placebo. On study Day 0, all subjects were challenged intranasally with rhinovirus type 39 (dose = 100 TCID50). Subjects were cloistered from Day 2 to Day 7, at which time they were treated with either chlorpheniramine or placebo. From 3 days before challenge to study Day 19, subjects had nasal patency assessed by rhinomanometry, eustachian tube function assessed by the 9-step test and sonotubometry, middle ear pressure assessed by tympanometry and nasal clearance assessed by the dyed-saccharin technique. Symptom diaries were maintained throughout the period of follow-up. During cloister, symptoms also were scored by interview, nasal secretions were quantified and nasal washings were performed for viral culture. Results showed that 19 (95%) subjects in the active-treatment group and 18 (90%) subjects in the placebo-treatment group shed virus. Symptomatic colds were observed in 63% of the active-treated and 83% of the placebo-treated subjects. Symptoms increased on Day 1 and peaked at Days 4 to 5. Detrimental changes in other measured functions consistent with those previously reported were observed. During the period of treatment, significant differences in the average symptom scores favoring the active-treatment group were observed for sneezing. Also, weight of expelled secretions was greater and mucociliary clearance rate less on some cloister days for the placebo-treated group. No significant differences between treatment groups in the objective measures of nasal congestion or the response of the middle ear and eustachian tube were documented.

  18. The solar kettle-thermos flask (SK-TF) and solar vacuum tube oven

    Energy Technology Data Exchange (ETDEWEB)

    Yak, Alex Kee Koo [AkayConsult Enterprise, Johor Bahru (Malaysia)

    2008-07-01

    The Solar Kettle-Thermos Flask (SK-TF) and Solar Vacuum Tube Oven (SaVeTao): A Cost Effective, Sustainable and Renewable Water Pasteurization and Food Processing System For The Developing World. Based on the perfect solar thermal energy harvesting paradigm of maximum solar radiation absorption and minimum loss of stored converted solar thermal energy, Solar Vacuum Glass Tubes (SVGT) indefinitely delivers solar pasteurized safe drinking water, powered solely by free solar energy. The SVGT is the heart of the SK-TF. Being vacuum insulated, the SK-TF doubles up as a vacuum flask, delivering stored solar heated water in the morning before the Sun is up. With a high stagnation temperature of more than 200 C, the SK-TF can also be used for other heating purposes e.g. an oven or autoclave. Powered solely by free solar energy, the SK-TF and SaVeTaO could very well be the answer in providing safe solar pasteurized drinking water and cooking to the global poor and needy in a sustainable and renewable way. (orig.)

  19. PWR steam generator tubing sample library

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    In order to compile the tubing sample library, two approaches were employed: (a) tubing sample replication by either chemical or mechanical means, based on field tube data and metallography reports for tubes already destructively examined; and (b) acquisition of field tubes removed from operating or retired steam generators. In addition, a unique mercury modeling concept is in use to guide the selection of replica samples. A compendium was compiled that summarizes field observations and morphologies of steam generator tube degradation types based on available NDE, destructive examinations, and field reports. This compendium was used in selecting candidate degradation types that were manufactured for inclusion in the tube library

  20. Steam generator tube performance

    International Nuclear Information System (INIS)

    Tatone, O.S.; Pathania, R.S.

    1984-10-01

    A review of the performance of steam generator tubes in 116 water-cooled nuclear power reactors showed that tubes were plugged at 54 (46 percent) of the reactors. The number of tubes removed from service decreased from 4 692 (0.30 percent) in 1981 to 3 222 (0.20 percent) in 1982. The leading causes of tube failures were stress corrosion cracking from the primary side, stress corrosion cracking (or intergranular attack) from the secondary side and pitting corrosion. The lowest incidence of corrosion-induced defects from the secondary side occurred in reactors that have used only volatile treatment, with or without condensate demineralization

  1. Steam generator tube performance

    International Nuclear Information System (INIS)

    Tatone, O.S.; Tapping, R.L.; Stipan, L.

    1992-03-01

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

  2. Microscopical investigation of steamside oxide on X20CrMoV121 superheater tubes

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Hansson, Anette Nørgaard; Jensen, Søren A.

    2011-01-01

    X20CrMoV121 is a 12%Cr martensitic steel which has been used in power plants in Europe for many decades. Superheater tubes exposed for various durations up to 135,000 hours in power plants in Denmark at steam temperatures varying from 450 to 575°C were investigated. Light optical and scanning ele...... electron microscopy was used to investigate steamside oxide morphologies. At all temperatures there is a double layered oxide, however, the inner:outer oxide thickness is not always equal. At the lower steam temperature range of...

  3. Sealed ion accelerator tubes (survey)

    International Nuclear Information System (INIS)

    Voitsik, L.R.

    1985-01-01

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

  4. Steam generator tube integrity program

    International Nuclear Information System (INIS)

    Dierks, D.R.; Shack, W.J.; Muscara, J.

    1996-01-01

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

  5. Measurement of anti-double-stranded DNA antibodies in major immunoglobulin classes

    Energy Technology Data Exchange (ETDEWEB)

    Aotsuka, S; Okawa, M; Ikebe, K; Yokohari, R [Division of Clinical Immunology, Clinical Research Institute, National Medical Center Hospital, Shinjuku-ku, Tokyo, Japan

    1979-07-10

    A solid-phase radioimmunoassay for quantitating anti-double-stranded deoxyribonucleic acid antibodies (anti-dsDNA) in IgG, IgM and IgA classes has been devised. A distinct feature of the method is an application of polystyrene tubes coated with poly-L-lysine, through which dsDNA could be bound firmly to a solid phase. Studies on patients sera as well as normal sera revealed that anti-dsDNA was not qualitatively but quantitatively characteristic of systematic lupus erythematosus (SLE) and that IgG anti-dsDNA levels correlated well with the disease activity.

  6. Tube plug removal machine

    International Nuclear Information System (INIS)

    Hawkins, P.J.

    1987-01-01

    In a nuclear steam generator wherein some faulty tubes have been isolated by mechanical plugging, to remove a selected plug without damaging the associated tube, a plug removal machine is used. The machine drills into a plug portion with a tap drill bit having a drill portion a tap portion and a threaded portion, engaging that plug portion with the threaded portion after the drilled hole has been threaded by the tap portion thereof, and removing a portion of the plug in the tube with a counterbore drill bit mounted concentrically about the tap drill bit. A trip pin and trip spline disengage the tap drill bit from the motor. The counterbore drill bit is thereafter self-centered with respect to the tube and plug about the now stationary tap drill bit. After a portion of the plug has been removed by the counterbore drill bit, pulling on the top drill bit by grippers on slots will remove the remaining plug portion from the tube. (author)

  7. Falling film evaporation on a tube bundle with plain and enhanced tubes

    International Nuclear Information System (INIS)

    Habert, M.

    2009-04-01

    The complexities of two-phase flow and evaporation on a tube bundle present important problems in the design of heat exchangers and the understanding of the physical phenomena taking place. The development of structured surfaces to enhance boiling heat transfer and thus reduce the size of evaporators adds another level of complexity to the modeling of such heat exchangers. Horizontal falling film evaporators have the potential to be widely used in large refrigeration systems and heat pumps, in the petrochemical industry and for sea water desalination units, but there is a need to improve the understanding of falling film evaporation mechanisms to provide accurate thermal design methods. The characterization of the effect of enhanced surfaces on the boiling phenomena occurring in falling film evaporators is thus expected to increase and optimize the performance of a tube bundle. In this work, the existing LTCM falling film facility was modified and instrumented to perform falling film evaporation measurements on single tube row and a small tube bundle. Four types of tubes were tested including: a plain tube, an enhanced condensing tube (Gewa-C+LW) and two enhanced boiling tubes (Turbo-EDE2 and Gewa-B4) to extend the existing database. The current investigation includes results for two refrigerants, R134a and R236fa, at a saturation temperature of T sat = 5 °C, liquid film Reynolds numbers ranging from 0 to 3000, at heat fluxes between 20 and 60 kW/m² in pool boiling and falling film configurations. Measurements of the local heat transfer coefficient were obtained and utilized to improve the current prediction methods. Finally, the understanding of the physical phenomena governing the falling film evaporation of liquid refrigerants has been improved. Furthermore, a method for predicting the onset of dry patch formation has been developed and a local heat transfer prediction method for falling film evaporation based on a large experimental database has been proposed

  8. Disconnection technique with a bronchial blocker for improving lung deflation: a comparison with a double-lumen tube and bronchial blocker without disconnection.

    Science.gov (United States)

    Yoo, Ji Young; Kim, Dae Hee; Choi, Ho; Kim, Kun; Chae, Yun Jeong; Park, Sung Yong

    2014-08-01

    One-lung ventilation (OLV) is accomplished with a double-lumen tube (DLT) or a bronchial blocker (BB). The authors compared the effectiveness of lung collapse using DLT, BB, and BB with the disconnection technique. Prospective, randomized, blind trial. A university hospital. Fifty-two patients undergoing elective pneumothorax surgery. Patients were assigned randomly to 1 of 3 groups: The DLT group (group 1), the BB group (group 2), and the BB with the disconnection technique group (group 3). The authors modified the disconnection technique in group 3 as follows: (1) turned off the ventilator and opened the adjustable pressure-limiting valve, allowing both lungs to collapse and (2) after loss of the CO2 trace on the capnograph, inflated the blocker cuff and turned on the ventilator, allowing only dependent-lung ventilation. Five and ten minutes after OLV, the degree of lung collapse was assessed by the surgeon, who was blinded to the isolation technique. The quality of lung collapse at 5 and 10 minutes was significantly better in groups 1 and 3 than in group 2. No significant differences were observed for the degree of lung collapse at any time point between groups 1 and 3. The average time for loss of the CO2 trace on the capnograph was 32.3±7.0 seconds in group 3. A BB with spontaneous collapse took longer to deflate and did not provide equivalent surgical exposure to the DLT. The disconnection technique could be helpful to accelerate lung collapse with a BB. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Steam generator tube performance

    International Nuclear Information System (INIS)

    Tatone, O.S.; Pathania, R.S.

    1982-04-01

    The performance of steam generator tubes in water-cooled nuclear power reactors has been reviewed for 1980. Tube defects occurred at 38% of the 97 reactors surveyed. This is a marginal improvement over 1979 when defects occurred at 41% of the reactors. The number of failed tubes was also lower, 0.14% of the tubes in service in 1980 compared with 0.20% of those in service in 1979. Analysis of the causes of these failures indicates that stress corrosion cracking was the leading failure mechanism. Reactors that used all-volatile treatment of secondary water, with or without full-flow condensate demineralization since start-up showed the lowest incidence of corrosion-related defects

  10. The dynamic single-tube concept; Le mono-tube dynamique

    Energy Technology Data Exchange (ETDEWEB)

    Rivet, P. [Ste MC International (France)

    1997-12-31

    In the framework of greenhouse gas emission reduction and the utilization of cooling intermediate fluids with indirect refrigerating systems, a new concept of dynamical single-tube has been developed, which allows for the simultaneous cold distribution from a centralized plant towards various required temperature systems (as for example in a supermarket refrigerating system) with optimized efficiency, fluid flow and defrosting conditions; moreover, the dynamic single-tube concept is very well adapted to two-phase flows

  11. Fuel assembly and fuel cladding tube

    International Nuclear Information System (INIS)

    Tsutsumi, Shinro; Ito, Ken-ichi; Inagaki, Masatoshi; Nakajima, Junjiro.

    1996-01-01

    A fuel cladding tube is a zirconium liner tube formed by lining a pure zirconium layer on the inner side of a zirconium alloy tube. The fuel cladding tube is formed by extrusion molding of a composite billet formed by inserting a pure zirconium billet into a zirconium alloy billet. Accordingly, the pure zirconium layer and the zirconium alloy tube are strongly joined by metal bond. The fuel cladding tube has an external oxide film on the outer surface of the zirconium alloy tube and an internal oxide film on the inner side of the pure zirconium layer. The external oxide film has a thickness preferably of about 1μm. The internal oxide film has a thickness of not more than 10μm, preferably, from 1 to 5μm. With such a constitution, flaws to be formed on both inner and outer surfaces of the cladding tube upon assembling a fuel assembly can be reduced thereby enabling to reduce the amount of hydrogen absorbed to the cladding tube. (I.N.)

  12. Comparison of digoxin concentration in plastic serum tubes with clot activator and heparinized plasma tubes.

    Science.gov (United States)

    Dukić, Lora; Simundić, Ana-Maria; Malogorski, Davorin

    2014-01-01

    Sample type recommended by the manufacturer for the digoxin Abbott assay is either serum collected in glass tubes or plasma (sodium heparin, lithium heparin, citrate, EDTA or oxalate as anticoagulant) collected in plastic tubes. In our hospital samples are collected in plastic tubes. Our hypothesis was that the serum sample collected in plastic serum tube can be used interchangeably with plasma sample for measurement of digoxin concentration. Our aim was verification of plastic serum tubes for determination of digoxin concentration. Concentration of digoxin was determined simultaneously in 26 venous blood plasma (plastic Vacuette, LH Lithium heparin) and serum (plastic Vacuette, Z Serum Clot activator; both Greiner Bio-One GmbH, Kremsmünster, Austria) samples, on Abbott AxSYM analyzer using the original Abbott Digoxin III assay (Abbott, Wiesbaden, Germany). Tube comparability was assessed using the Passing Bablok regression and Bland-Altman plot. Serum and plasma digoxin concentrations are comparable. Passing Bablok intercept (0.08 [95% CI = -0.10 to 0.20]) and slope (0.99 [95% CI = 0.92 to 1.11]) showed there is no constant or proportional error. Blood samples drawn in plastic serum tubes and plastic plasma tubes can be interchangeably used for determination of digoxin concentration.

  13. Dermatology on YouTube.

    Science.gov (United States)

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

    2014-06-15

    YouTube, reaches upwards of six billion users on a monthly basis and is a unique source of information distribution and communication. Although the influence of YouTube on personal health decision-making is well established, this study assessed the type of content and viewership on a broad scope of dermatology related content on YouTube. Select terms (i.e. dermatology, sun protection, skin cancer, skin cancer awareness, and skin conditions) were searched on YouTube. Overall, the results included 100 videos with over 47 million viewers. Advocacy was the most prevalent content type at 24% of the total search results. These 100 videos were "shared" a total of 101,173 times and have driven 6,325 subscriptions to distinct YouTube user pages. Of the total videos, 35% were uploaded by or featured an MD/DO/PhD in dermatology or other specialty/field, 2% FNP/PA, 1% RN, and 62% other. As one of the most trafficked global sites on the Internet, YouTube is a valuable resource for dermatologists, physicians in other specialties, and the general public to share their dermatology-related content and gain subscribers. However, challenges of accessing and determining evidence-based data remain an issue.

  14. Bacterial Biofilms in Jones Tubes.

    Science.gov (United States)

    Ahn, Eric S; Hauck, Matthew J; Kirk Harris, Jonathan; Robertson, Charles E; Dailey, Roger A

    To investigate the presence and microbiology of bacterial biofilms on Jones tubes (JTs) by direct visualization with scanning electron microscopy and polymerase chain reaction (PCR) of representative JTs, and to correlate these findings with inflammation and/or infection related to the JT. In this study, prospective case series were performed. JTs were recovered from consecutive patients presenting to clinic for routine cleaning or recurrent irritation/infection. Four tubes were processed for scanning electron microscopy alone to visualize evidence of biofilms. Two tubes underwent PCR alone for bacterial quantification. One tube was divided in half and sent for scanning electron microscopy and PCR. Symptoms related to the JTs were recorded at the time of recovery. Seven tubes were obtained. Five underwent SEM, and 3 out of 5 showed evidence of biofilms (60%). Two of the 3 biofilms demonstrated cocci and the third revealed rods. Three tubes underwent PCR. The predominant bacteria identified were Pseudomonadales (39%), Pseudomonas (16%), and Staphylococcus (14%). Three of the 7 patients (43%) reported irritation and discharge at presentation. Two symptomatic patients, whose tubes were imaged only, revealed biofilms. The third symptomatic patient's tube underwent PCR only, showing predominantly Staphylococcus (56%) and Haemophilus (36%) species. Two of the 4 asymptomatic patients also showed biofilms. All symptomatic patients improved rapidly after tube exchange and steroid antibiotic drops. Bacterial biofilms were variably present on JTs, and did not always correlate with patients' symptoms. Nevertheless, routine JT cleaning is recommended to treat and possibly prevent inflammation caused by biofilms.

  15. Rectangular drift tube characteristics

    International Nuclear Information System (INIS)

    Denisov, D.S.; Musienko, Yu.V.

    1985-01-01

    Results on the study of the characteristics of a 50 x 100 mm aluminium drift tube are presented. The tube was filled with argon-methane and argon-isobutane mixtures. With 16 per cent methane concentration the largest deviation from a linear relation between the drift time and the drift path over 50 mm is less than 2 mm. The tube filled with argon-isobutane mixture is capable of operating in a limited streamer mode

  16. Tube Inner Coating of Non-Conductive Films by Pulsed Reactive Coaxial Magnetron Plasma with Outer Anode

    Directory of Open Access Journals (Sweden)

    Musab Timan Idriss Gasab

    2018-03-01

    Full Text Available The double-ended coaxial magnetron pulsed plasma (DCMPP method with auxiliary outer anode was introduced in order to achieve the uniform coating of non-conductive thin films on the inner walls of insulator tubes. In this study, titanium (Ti was employed as a cathode (sputtering target, and a glass tube was used as a substrate. In an argon (Ar and oxygen (O2 gas mixture, magnetron plasma was generated. Oxygen gas was introduced to deposit a titanium oxide (TiO2 film. A comparison between films coated with and without an auxiliary outer anode was made. As a result, it was clearly shown that the DCMPP method using an auxiliary outer anode enhanced the uniformity of the deposited non-conductive film compared to the conventional DCMPP method. Moreover, the optimum conditions under which the thin TiO2 film was deposited on the inner wall of the glass tube were revealed. From the results, it was supposed that the auxiliary outer anode contributed to the uniformity of the distributions of deposited negative charge on the non-conductive film and consequently the electric field and the plasma density uniform.

  17. Chest tube insertion - series (image)

    Science.gov (United States)

    Chest tubes are inserted to drain blood, fluid, or air and allow full expansion of the lungs. The tube is placed in the pleural space. The area where the tube will be inserted is numbed (local anesthesia). The patient may also be sedated. The chest ...

  18. Vocal Fold Adjustment Caused by Phonation Into a Tube: A Double-Case Study Using Computed Tomography

    Czech Academy of Sciences Publication Activity Database

    Hampala, V.; Laukkanen, A. M.; Guzman, M.; Horáček, Jaromír; Švec, J. G.

    2015-01-01

    Roč. 29, č. 6 (2015), s. 733-742 ISSN 0892-1997 R&D Projects: GA ČR(CZ) GAP101/12/1306 Institutional support: RVO:61388998 Keywords : vocal folds * resonance tube * computed tomography Subject RIV: BI - Acoustics Impact factor: 1.113, year: 2015 http://ac.els-cdn.com/S0892199714002756/1-s2.0-S0892199714002756-main.pdf?_tid=58e41ed4-d4be-11e5-b79c-00000aab0f01&acdnat=1455635150_c180f8db4970456952fb802bf329392b

  19. Self-propelled in-tube shuttle and control system for automated measurements of magnetic field alignment

    International Nuclear Information System (INIS)

    Boroski, W.N.; Nicol, T.H.; Pidcoe, S.V.

    1990-03-01

    A magnetic field alignment gauge is used to measure the field angle as a function of axial position in each of the magnets for the Superconducting Super Collider (SSC). Present measurements are made by manually pushing the through the magnet bore tube and stopping at intervals to record field measurements. Gauge location is controlled through graduation marks and alignment pins on the push rods. Field measurements are recorded on a logging multimeter with tape output. Described is a computerized control system being developed to replace the manual procedure for field alignment measurements. The automated system employs a pneumatic walking device to move the measurement gauge through the bore tube. Movement of the device, called the Self-Propelled In-Tube Shuttle (SPITS), is accomplished through an integral, gas driven, double-acting cylinder. The motion of the SPITS is transferred to the bore tube by means of a pair of controlled, retractable support feet. Control of the SPITS is accomplished through an RS-422 interface from an IBM-compatible computer to a series of solenoid-actuated air valves. Direction of SPITS travel is determined by the air-valve sequence, and is managed through the control software. Precise axial position of the gauge within the magnet is returned to the control system through an optically-encoded digital position transducer attached to the shuttle. Discussed is the performance of the transport device and control system during preliminary testing of the first prototype shuttle. 1 ref., 7 figs

  20. 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.

  1. Flux tubes at finite temperature

    Energy Technology Data Exchange (ETDEWEB)

    Cea, Paolo [INFN, Sezione di Bari,Via G. Amendola 173, I-70126 Bari (Italy); Dipartimento di Fisica dell’Università di Bari,Via G. Amendola 173, I-70126 Bari (Italy); Cosmai, Leonardo [INFN, Sezione di Bari,Via G. Amendola 173, I-70126 Bari (Italy); Cuteri, Francesca; Papa, Alessandro [Dipartimento di Fisica, Università della Calabria & INFN-Cosenza,Ponte Bucci, cubo 31C, I-87036 Rende (Cosenza) (Italy)

    2016-06-07

    The chromoelectric field generated by a static quark-antiquark pair, with its peculiar tube-like shape, can be nicely described, at zero temperature, within the dual superconductor scenario for the QCD confining vacuum. In this work we investigate, by lattice Monte Carlo simulations of the SU(3) pure gauge theory, the fate of chromoelectric flux tubes across the deconfinement transition. We find that, if the distance between the static sources is kept fixed at about 0.76 fm ≃1.6/√σ and the temperature is increased towards and above the deconfinement temperature T{sub c}, the amplitude of the field inside the flux tube gets smaller, while the shape of the flux tube does not vary appreciably across deconfinement. This scenario with flux-tube “evaporation” above T{sub c} has no correspondence in ordinary (type-II) superconductivity, where instead the transition to the phase with normal conductivity is characterized by a divergent fattening of flux tubes as the transition temperature is approached from below. We present also some evidence about the existence of flux-tube structures in the magnetic sector of the theory in the deconfined phase.

  2. Managing a chest tube and drainage system.

    Science.gov (United States)

    Durai, Rajaraman; Hoque, Happy; Davies, Tony W

    2010-02-01

    Intercostal drainage tubes (ie, chest tubes) are inserted to drain the pleural cavity of air, blood, pus, or lymph. The water-seal container connected to the chest tube allows one-way movement of air and liquid from the pleural cavity. The container should not be changed unless it is full, and the chest tube should not be clamped unnecessarily. After a chest tube is inserted, a nurse trained in chest-tube management is responsible for managing the chest tube and drainage system. This entails monitoring the chest-tube position, controlling fluid evacuation, identifying when to change or empty the containers, and caring for the tube and drainage system during patient transport. This article provides an overview of indications, insertion techniques, and management of chest tubes. Copyright 2010 AORN, Inc. Published by Elsevier Inc. All rights reserved.

  3. 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.

  4. Bottom nozzle to guide tube connection

    International Nuclear Information System (INIS)

    Bryan, W.J.

    1991-01-01

    This patent describes a nuclear fuel assembly which includes an upper end fitting and a lower end fitting spaced therefrom and connected thereto by elongated guide tubes of one alloy having an open upper end and a closed lower end with spaced fuel element retaining grids mounted on the guide tubes therebetween, the closed lower ends of the guide tubes including a threaded central passageway and the attachment of the guide tubes to the lower end fitting of another alloy. It comprises: an externally threaded bolt with a first end threadably received in the threaded central passageway of the lower end of the guide tube and a head at the other end of the side of the lower end fitting opposite the guide tube; an interruption in the external threads of the bolt which forms a groove which communicates the interior of the guide tube with the side of the lower end fitting opposite the guide tube and enhances its frictional engagement with the threaded central passageway, thereby to hold and attach the guide tube and lower end fitting firmly together, even through a series of temperature cycles

  5. Analysis of a double-pipe heat exchanger performance using heat structure coupling of MARS and CUPID

    International Nuclear Information System (INIS)

    Amidua, M.; Kim, H.; Cho, H. K.

    2015-01-01

    Thermal hydraulic phenomena in the inner tube of the double-pipe heat exchanger are expected to be reproducible by one-dimensional system analysis codes (MARS) if a proper condensation heat transfer coefficient is applied. Jeon et al (2013) and Cho et al (2013) conducted comprehensive reviews of the predictive capability of the condensation heat transfer models for the steam-water stratified flow. On the contrary, in the outer tube, a multidimensional analysis tool is required to incorporate the influence of azimuthal angle on the heat transfer rate from the inner tube outer wall to the outer tube fluid. Therefore, a coupled calculation between one dimensional system analysis code and a multidimensional computational fluid dynamics code is an attainable way to predict this effect with a reliable accuracy. CUPID is a three-dimensional computational multiphase fluid dynamics code developed by KAERI (Korea Atomic Energy Research Institute). According to Jeong et al (2010), the objective of the development is to support a resolution for the thermal hydraulic issues regarding the transient multi-dimensional twophase phenomena which can arise in an advanced light water reactor. It uses two-fluid model for the governing equations, which uses two sets of Navier-Stokes' equations for two phases. It can be used as either a typical CFD code or a component code (porous CFD code) depending on the length scale of the phenomena that need to be resolved. On the other hand, MARS is a best estimate thermalhydraulic system code and it was developed at KAERI by consolidating and restructuring the RELAP5/MOD3.2 code and COBRA-TF code (Cho et al., 2014). The MARS code has the capability to analyze best-estimated thermal hydraulic system. In this study, the coupled CUPID-MARS code was used for the simulation of a double-pipe heat exchanger. This paper presents the description of the heat exchanger, the coupling method, and the simulation results using the coupled code. The coupling

  6. Cross-talk in straw tube chambers

    Energy Technology Data Exchange (ETDEWEB)

    Marzec, J. E-mail: janusz.marzec@ire.pw.edu.pl

    2003-05-11

    An analytical model of the signal transmission between neighboring straw tubes with resistive cathodes (cross-talk) is presented. The dependence of the cross-talk level on the cathode resistance, tube length, particle detection point, the distance of the tube from the shielding planes, and termination of the tube ends is analyzed.

  7. Cross-talk in straw tube chambers

    International Nuclear Information System (INIS)

    Marzec, J.

    2003-01-01

    An analytical model of the signal transmission between neighboring straw tubes with resistive cathodes (cross-talk) is presented. The dependence of the cross-talk level on the cathode resistance, tube length, particle detection point, the distance of the tube from the shielding planes, and termination of the tube ends is analyzed

  8. Electric Double-Layer Capacitor Fabricated with Addition of Carbon Nanotube to Polarizable Electrode

    International Nuclear Information System (INIS)

    Yoshiyuki, S.

    2012-01-01

    Electrical double-layer capacitor (EDLC) was fabricated with addition of carbon nano tube (CNT) to polarization electrodes as a conducting material. The CNT addition reduced the series resistance of the EDLC by one-twentieth, while the capacitance was not increased by the CNT addition. The low series resistance leaded to the high electrical energy stored in the EDLC. In this paper, the dependence of the series resistance, the specific capacitance, the energy, and the energy efficiencies on the CNT addition is discussed

  9. Double hard scattering without double counting

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, Markus [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Gaunt, Jonathan R. [VU Univ. Amsterdam (Netherlands). NIKHEF Theory Group; Schoenwald, Kay [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2017-02-15

    Double parton scattering in proton-proton collisions includes kinematic regions in which two partons inside a proton originate from the perturbative splitting of a single parton. This leads to a double counting problem between single and double hard scattering. We present a solution to this problem, which allows for the definition of double parton distributions as operator matrix elements in a proton, and which can be used at higher orders in perturbation theory. We show how the evaluation of double hard scattering in this framework can provide a rough estimate for the size of the higher-order contributions to single hard scattering that are affected by double counting. In a numeric study, we identify situations in which these higher-order contributions must be explicitly calculated and included if one wants to attain an accuracy at which double hard scattering becomes relevant, and other situations where such contributions may be neglected.

  10. Double hard scattering without double counting

    International Nuclear Information System (INIS)

    Diehl, Markus; Gaunt, Jonathan R.

    2017-02-01

    Double parton scattering in proton-proton collisions includes kinematic regions in which two partons inside a proton originate from the perturbative splitting of a single parton. This leads to a double counting problem between single and double hard scattering. We present a solution to this problem, which allows for the definition of double parton distributions as operator matrix elements in a proton, and which can be used at higher orders in perturbation theory. We show how the evaluation of double hard scattering in this framework can provide a rough estimate for the size of the higher-order contributions to single hard scattering that are affected by double counting. In a numeric study, we identify situations in which these higher-order contributions must be explicitly calculated and included if one wants to attain an accuracy at which double hard scattering becomes relevant, and other situations where such contributions may be neglected.

  11. Tubing cutter for tight spaces

    Science.gov (United States)

    Girala, A. S.

    1980-01-01

    Cutter requires few short swings of handle to rotate its cutting edge full 360 around tube. It will cut tubing installed in confined space that prevents free movement of conventional cutter. Cutter is snapped onto tube and held in place by spring-loaded clamp. Screw ratchet advances cutting wheel.

  12. Evaluation of the Effect of Tube Pitch and Surface Alterations on Temperature Field at Sprinkled Tube Bundle

    Directory of Open Access Journals (Sweden)

    Kracík Petr

    2015-01-01

    Full Text Available Water flowing on a sprinkled tube bundle forms three basic modes: It is the Droplet mode (liquid drips from one tube to another, the Jet mode (with an increasing flow rate droplets merge into a column and the Membrane (Sheet mode (with further increasing of falling film liquid flow rate columns merge and create sheets between the tubes. With sufficient flow rate sheets merge at this state and the tube bundle is completely covered by a thin liquid film. There are several factors influencing the individual mode types as well as heat transfer. Beside the above mentioned falling film liquid flow rate they are for instance tube diameters, tube pitches in a tube bundle or a physical condition of a falling film liquid. This paper presents a summary of data measured at atmospheric pressure at a tube bundle consisting of copper tubes of 12 milimeters diameter and of the studied tube length one meter. The tubes are positioned horizontally one above another with the tested pitches of 15, 20, 25 and 30 mm and there is a distribution tube placed above them with water flowing out. The thermal gradient of 15–40 has been tested with all pitches where the falling film liquid’s temperature at the inlet of the distribution tube was 15 °C. The liquid was heated during the flow through the exchanger and the temperature of the sprinkled (heater liquid at the inlet of the exchanger with a constant flow rate about 7.2 litres per minute was 40 °C. The tested flow of the falling film liquid ranged from 1.0 to 13.0 litres per minute. Sequences of 180 exposures have been recorded in partial flow rate stages by thermographic camera with record frequency of 30 Hz which were consequently assessed using the Matlab programme. This paper presents results achieved at the above mentioned pitches and at three types of tube bundle surfaces.

  13. An investigation on mechanical property of commercial copper tube to aluminium 2025 tube plate by FWTPET process

    Energy Technology Data Exchange (ETDEWEB)

    Kannan, S., E-mail: kannan.dgl201127@gmail.com [Department of Mechanical Engineering and Mining Machinery Engineering, Indian Institute of Technology (ISM), Dhanbad, Jharkhand 826004 (India); Senthil Kumaran, S., E-mail: sskumaran@ymail.com [Research and Development Center, Department of Mechanical Engineering, RVS Educational Trust' s Group of Institutions, RVS School of Engineering and Technology, Dindigul, Tamilnadu 624005 (India); Kumaraswamidhas, L.A., E-mail: lakdhas1978@gmail.com [Department of Mechanical Engineering and Mining Machinery Engineering, Indian Institute of Technology (ISM), Dhanbad, Jharkhand 826004 (India)

    2016-07-05

    Frictional welding of tube to tube plate by external tool (FWTPET) posses wide spread industrial in mass production process for joint similar and dissimilar materials. Frictional welding process allows welding of some materials that are exceptionally hard to fusion weld. The good quality joint between the tube and tube plate is achieved by selecting the proper process parameter. In this present research, the frictional welding is done between the Aluminium 2025 tube plate and commercial copper tube possessing a clearance fit of 0.1 mm between tube and hole. In this study, two conditions were considered while handing out this experiment. The condiction1 is tube without holes [WOH] and condition 2 is tube with holes [WH] on the tube circumference. In total, twenty seven work pieces have been considered separately for both conditions and the mechanical property such as compression strength and hardness value has been measured for the both set of work piece in two conditions to analysis the joint strength of the welding process. Taguchi L{sub 27} orthogonal array has been used in this process to identify the process parameter which influences the joint strength of the welded samples. ANOVA method is used to calculate the percentage of contribution by each process parameter which influences the better joint strength. Genetic algorithm is used to authenticate the outcome obtained from the both experimental value and optimization value. Scanning Electron Microscope (SEM) and Energy-dispersive X-ray analysis (EDX) has been performed to probe microstructures and chemical compositions for work piece without holes which has higher mechanical property. - Highlights: • FWTPET for dissimilar metals commercial copper tube and Al 2025 tube plate. • The hardness value for tube without holes are 180.988 Hv. • The compression strength for tube without holes are 376.05 MPa. • SEM confirm heat production is done to melt parent metal by diffusion process. • EDX prove no trace

  14. Internal heat exchange tubes for industrial furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Hoetzl, M.; Lingle, T.M.

    1992-05-26

    This patent describes a method for cooling the work within an industrial furnace. It comprises providing a longitudinally extending outer tube which extends into the furnace having a closed axial end and an open axial end; providing a preformed inner tube open at both ends within the outer tube; injecting a coolant into the inner tube so that the coolant flows from one axial end of the tube out the opposite end adjacent the closed end of the outer tube, and from the closed end of the outer tube to the open end thereof; circulating a gas within the furnace against the outer tube to effect heat transfer therewith.

  15. Square through tube

    International Nuclear Information System (INIS)

    Akita, Junji; Honma, Toei.

    1975-01-01

    Object: To provide a square through tube involving thermal movement in pipelines such as water supply pump driving turbine exhaust pipe (square-shaped), which is wide in freedom with respect to shape and dimension thereof for efficient installation at site. Structure: In a through tube to be airtightly retained for purpose of decontamination in an atomic power plant, comprising a seal rubber plate, a band and a bolt and a nut for securing said plate, the seal rubber plate being worked into the desired shape so that it may be placed in intimate contact with the concrete floor surface by utilization of elasticity of rubber, thereby providing airtightness at a corner portion of the square tube. (Kamimura, M.)

  16. Process and device for locating a defective tube, particularly in the tube bundle of a steam generator

    International Nuclear Information System (INIS)

    Denis, Jean.

    1977-01-01

    A process is described for locating a defective tube, particularly in the tube bundle of a steam generator of the reversed U tube kind with the ends connected to a tube plate, marking with the bottom of the generator casing a space separated into two adjacent collectors, respectively for the inlet and outlet of a primary fluid flowing inside the tubes of the bundle, these being externally washed by a secondary vaporizing fluid. In this process a television camera that can be inserted into the casing is used. This process consists in transmitting to a display system outside the generator an image of the tube plate in each collector by means of a directional television camera and then to place over this image a luminous marker to locate the end or the faulty tube [fr

  17. Gastrostomy feeding tube - bolus

    Science.gov (United States)

    Feeding - gastrostomy tube - bolus; G-tube - bolus; Gastrostomy button - bolus; Bard Button - bolus; MIC-KEY - bolus ... KEY, 3 to 8 weeks after surgery. These feedings will help your child grow strong and healthy. ...

  18. Feedwater heater tube-to-tubesheet connections

    International Nuclear Information System (INIS)

    Yokell, S.

    1993-01-01

    This paper discusses some practical aspects of expanded, welded, and welded-and-expanded feedwater heater tube-to-tubesheet joints. It outlines elastic-plastic tube expanding theory. It examines uniform-pressure-expanded tube joint strength and correlating roller-expanded joint strength with wall reduction and rolling torque. For materials subject to stress-corrosion cracking (SCC), it recommends heat treating tube ends before expanding. For materials subject to fatigue and tube-end cracking, it advocates two-stage expanding: (1) expanding enough to create firm tube-hole contact over the full tubesheet thickness; and (2) re-expanding at full pressure or torque. The paper emphasizes the desirability of segregating heats of tubing, mapping the tube-heat locations and making the heat map a permanent part of the heater maintenance file. It recommends when to provide TEMA/HEI Power Plant Standard annular grooves for roller-expanding and provides an equation for determining optimum groove width for uniform-pressure expanding. The paper also reviews welding requirements for welds of tubes to tubesheets. The review covers front-face welding before and after expanding and the reasons for welding first. It outlines current thinking about definitions of strength- and seal-welds of front-face welded joint in terms of their functions and load-carrying abilities. It presents a proposal for determining the required size of strength welds for use in Section VIII of the ASME Boiler and Pressure Vessel Code (the Code). It shows why welded-and-expanded feedwater heater tube-to-tubesheet joints should be full-strength and full-depth expanded. It makes recommendations for pressure- and leak-testing. This work also proposes the industry consider butt welding the tubes to the steam-side face of the tubesheet as a regular method of tube joining. The results of a survey of manufacturers practices are appended. 30 refs., 14 figs

  19. Pressure loss characteristics of LSTF steam generator heat-transfer tubes. Pressure loss increase due to tube internal instruments

    International Nuclear Information System (INIS)

    Suzuki, Mitsuhiro

    1994-11-01

    The steam generator of the Large-Scale Test Facility (LSTF) includes 141 heat-transfer U-tubes with different lengths. Six U-tubes among them are furnished with 15 or 17 probe-type instruments (conduction probe with a thermocouple; CPT) protuberant into the primary side of the U-tubes. Other 135 U-tubes are not instrumented. This results in different hydraulic conditions between the instrumented and non-instrumented U-tubes with the same length. A series of pressure loss characteristics tests was conducted at a test apparatus simulating both types of U-tube. The following pressure loss coefficient (K CPT ) was reduced as a function of Reynolds number (Re) from these tests under single-phase water flow conditions. K CPT =0.16 5600≤Re≤52820, K CPT =60.66xRe -0.688 2420≤Re≤5600, K CPT =2.664x10 6 Re -2.06 1371≤Re≤2420. The maximum uncertainty is 22%. By using these results, the total pressure loss coefficients of full length U-tubes were estimated. It is clarified that the total pressure loss of the shortest instrumented U-tube is equivalent to that of the middle-length non-instrumented U-tube and also that a middle-length instrumented U-tube is equivalent to the longest non-instrumented U-tube. Concludingly. it is important to take account of the CPT pressure loss mentioned above in estimation of fluid behavior at the non-instrumented U-tubes either by using the LSTF experiment data from the CPT-installed U-tubes or by using any analytical codes. (author)

  20. Isolated Fallopian Tube Torsion in Adolescents

    Directory of Open Access Journals (Sweden)

    S. Rajaram

    2013-01-01

    Full Text Available Background. Fallopian tube torsion is a rare cause of acute abdomen, occurring commonly in females of reproductive age. It lacks pathognomonic symptoms, signs, or imaging features, thus causing delay in surgical intervention. Case. We report two cases of isolated fallopian tube torsion in adolescent girls. In the first case a 19-year-old patient presented with acute pain in the left iliac region associated with episodes of vomiting for one day and mild tenderness on examination. Laparoscopy revealed left sided twisted fallopian tube associated with hemorrhagic cyst of ovary. The tube was untwisted and salvaged. In another case an 18-year-old virgin girl presented with similar complaints since one week, associated with mild tenderness in the lower abdomen and tender cystic mass on per rectal examination. On laparoscopy right twisted fallopian tube associated with a paratubal cyst was found. Salpingectomy was done as the tube was gangrenous. Conclusion. Fallopian tube torsion, though rare, should be considered in women of reproductive age with unilateral pelvic pain. Early diagnostic laparoscopy is important for an accurate diagnosis and could salvage the tube.

  1. Experiment data report for Semiscale Mod-1 test S-28-3 (steam generator tube rupture test)

    International Nuclear Information System (INIS)

    Gillins, R.L.; Sackett, K.E.

    1977-10-01

    Recorded test data are presented for Test S-28-3 of the Semiscale Mod-1 steam generator tube rupture test series. These tests are among several Semiscale Mod-1 experiments conducted to investigate the thermal and hydraulic phenomena accompanying a hypothesized loss-of-coolant accident in a pressurized water reactor (PWR) system. Test S-28-3 was conducted from initial conditions of 15621 kPa and 555 K to investigate the response of the Semiscale Mod-1 system to a depressurization and reflood transient following a simulated double-ended offset shear of the broken loop cold leg piping. During the test, cooling water was injected into the cold leg of the intact and broken loops to simulate emergency core coolant injection in a PWR. Twelve steam generator tube ruptures were simulated by a controlled injection from a heated accumulator into the intact loop hot leg

  2. Experiment data report for semiscale Mod-1 test S-28-2 (steam generator tube rupture test)

    International Nuclear Information System (INIS)

    Patton, M.L.; Sackett, K.E.

    1977-10-01

    Recorded test data are presented for Test S-28-2 of the Semiscale Mod-1 steam generator tube rupture test series. These tests are among several Semiscale Mod-1 experiments conducted to investigate the thermal and hydraulic phenomena accompanying a hypothesized loss-of-coolant accident in a pressurized water reactor (PWR) system. Test S-28-2 was conducted from initial conditions of 15 936 kPa and 558 K to investigate the response of the Semiscale Mod-1 system to a depressurization and reflood transient following a simulated double-ended offset shear of the broken loop cold leg piping. During the test, cooling water was injected into the cold leg of the intact and broken loops to simulate emergency core coolant injection in a PWR. For Test S-28-2, accumulator injection into the intact loop hot leg was provided to simulate simulate the rupture of six steam generator tubes

  3. Experiment data report for semiscale Mod-1 test S-28-4 (steam generator tube rupture test)

    International Nuclear Information System (INIS)

    Esparza, V.; Sackett, K.E.

    1977-10-01

    Recorded test data are presented for Test S-28-4 of the Semiscale Mod-1 steam generator tube rupture test series. These tests are among several Semiscale Mod-1 experiments conducted to investigate the thermal and hydraulic phenomena accompanying a hypothesized loss-of-coolant accident in a pressurized water reactor (PWR) system. Test S-28-4 was conducted from initial conditions of 15 646 kPa and 557 K to investigate the response of the Semiscale Mod-1 system to a depressurization and reflood transient following a simulated double-ended offset shear of the broken loop cold leg piping. During the test, cooling water was injected into the cold leg of the intact and broken loops to simulate emergency core coolant injection in a PWR. Thirty steam generator tube ruptures were simulated by a controlled injection from a heated accumulator into the intact loop hot leg

  4. Sleeving repair of heat exchanger tubes

    International Nuclear Information System (INIS)

    Street, Michael D.; Schafer, Bruce W.

    2000-01-01

    Defective heat exchanger tubes can be repaired using techniques that do not involve the cost and schedule penalties of component replacement. FTI's years of experience repairing steam generator tubes have been successfully applied to heat exchangers. Framatome Technologies heat exchanger sleeves can bridge defective areas of the heat exchanger tubes, sleeves have been designed to repair typical heat exchanger tube defects caused by excessive tube vibration, stress corrosion cracking, pitting or erosion. By installing a sleeve, the majority of the tube's heat transfer and flow capacity is maintained and the need to replace the heat exchanger can be delayed or eliminated. Both performance and reliability are improved. FTI typically installs heat exchanger tube sleeves using either a roll expansion or hydraulic expansion process. While roll expansion of a sleeve can be accomplished very quickly, hydraulic expansion allows sleeves to be installed deep within a tube where a roll expander cannot reach. Benefits of FTI's heat exchanger tube sleeving techniques include: - Sleeves can be positioned any where along the tube length, and for precise positioning of the sleeve eddy current techniques can be employed. - Varying sleeve lengths can be used. - Both the roll and hydraulic expansion processes are rapid and both produce joints that do not require stress relief. - Because of low leak rates and speed of installations, sleeves can be used to preventatively repair likely-to-fail tubes. - Sleeves can be used for tube stiffening and to limit leakage through tube defects. - Because of installation speed, there is minimal impact on outage schedules and budgets. FTI's recently installed heat exchanger sleeving at the Kori-3 Nuclear Power Station in conjunction with Korea Plant Service and Engineering Co., Ltd. The sleeves were installed in the 3A and 3B component cooling water heat exchangers. A total of 859 tubesheet and 68 freespan sleeves were installed in the 3A heat

  5. Small size neutron tube UNG-1

    International Nuclear Information System (INIS)

    Bespalov, D.F.; Mints, A.Z.; Shkol'nikov, A.S.

    A tube UNG-1 (universal neutron gas-filled) is designed for the use in the well neutron generators IGN-1 and IGN-1-M (a pulse neutron generator). Their serial production in the USSR has been started in 1963. At the same year, the serial production of the tubes UNG-1 has been started. Thus, this tube is the first serial logging accelerating tube in the USSR. A Penning source, equipped with a hot cathode, was selected as an ion source of the tube

  6. Thru-tubing inflatable workover systems

    International Nuclear Information System (INIS)

    Coronado, M.P.; Mody, R.K.; Craig, G.C.

    1991-01-01

    Recent technological advances in inflatable packing element design has allowed non-conventional workover techniques to be accomplished through the production tubing. The improved capabilities of these elements, coupled with new tool designs allowing workovers to be completed with coiled tubing or electric wireline, has seen growing applications. These workovers include, selective and zonal chemical treatments, temporary and permanent plugback operations, intermediate zone blankoff, production and injection flow profile modifications and formation fracturing. They are completed without pulling the production tubing from the well, and thus do not require a rig on the well. Since these tools are snubbed in the well with coiled tubing or electric wireline, thus eliminating the need to kill the well, heavy weight kill fluids, which may cause formation damage, are not required. These tools have been designed to operate with hydraulic pressure and workstring tension within the coiled tubing limitations. This paper outlines the development of these Thru-tubing systems and application techniques that have been developed as a result of their field use. It discusses case histories of applications using this technology and the resulting increase in well performance. This paper also describes auxiliary equipment that has been developed to allow these tool systems to be used safely on coiled tubing and electric wireline

  7. Tubing vs. buckets: a cost comparison

    Science.gov (United States)

    Neil K. Huyler

    1975-01-01

    Equipment investment for tubing-vacuum systems was significantly less than that for bucket systems. Tubing-vacuum systems required about 22 percent less labor input, the major labor input being completed before sap-flow periods. Annual cost of operation was less for tubing-vacuum than the bucket system. Small tubing-vacuum operations showed more profit potential than...

  8. Small-bore chest tubes seem to perform better than larger tubes in treatment of spontaneous pneumothorax

    DEFF Research Database (Denmark)

    Iepsen, Ulrik Winning; Ringbæk, Thomas

    2013-01-01

    The aim of this study was to compare the efficacy and complications of surgical (large-bore) chest tube drainage with smaller and less invasive chest tubes in the treatment of non-traumatic pneumothorax (PT). ......The aim of this study was to compare the efficacy and complications of surgical (large-bore) chest tube drainage with smaller and less invasive chest tubes in the treatment of non-traumatic pneumothorax (PT). ...

  9. Feeding tube insertion - gastrostomy

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002937.htm Feeding tube insertion - gastrostomy To use the sharing features on this page, please enable JavaScript. A gastrostomy feeding tube insertion is the placement of a feeding ...

  10. 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.

  11. Improving the calandria tubes for CANDU reactors

    International Nuclear Information System (INIS)

    Coleman, C.E.; Fong, R.W.L.; Doubt, G.L.

    1997-01-01

    CANDU calandria tubes are made from annealed Zircaloy-2 sheet formed into a cylinder and welded along its length to make the tube. The current calandria tubes have given exemplary service for many years. With more stringent regulations and the need to accommodate warm cooling water in tropical countries, we started a development program to increase the margins for failure during postulated accidents. These improvements involve increasing the tube strength and optimising the heat-transfer from an excessively hot fuel channel to the cool moderator. If the postulated accident involves a pressure tube break, it would be desirable if the calandria tube withstood the full pressure of the heat-transport system. The weakest link in current calandria tubes is the weld. Thickening the weld can increase the strength by 20% while seamless tubes can be 45% stronger than current tubes. The latter tubes can hold full system pressure for many hours without failure. If during the postulated accident the fuel and pressure tube become excessively hot but do not touch the calandria tube, the radiant heat loss must be maximised. Current calandria tubes have an absorptivity (emissivity) of about 0.2. To protect the fuel and the fuel channel we have devised a finish to the inside surface of the calandria tube that increases the emissivity to 0.7. If during the postulated accident the hot pressure tube touches the cool calandria tube, the contact conductance and the critical heat flux must be optimised to ensure nucleate boiling of the moderator at the outside surface of the calandria tube and therefore efficient exploitation of the moderator as a heat sink. In laboratory tests small ridges on the inside surface and roughening of the outside surface have been shown to increase the margins against failure and increase the possible moderator temperatures thus providing the opportunity to decrease the cost of the moderator heat-exchange system and remove restrictions on reactor operation in

  12. Heat transfer of a helical double-pipe vertical evaporator: Theoretical analysis and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Colorado-Garrido, D.; Santoyo-Castelazo, E. [Posgrado en Ingenieria y Ciencias Aplicadas, Universidad Autonoma del Estado de Morelos, Av. Universidad 1001. Col. Chamilpa, C.P. 62209 Cuernavaca, Morelos (Mexico); Hernandez, J.A.; Siqueiros, J.; Juarez-Romero, D. [Centro de Investigacion en Ingenieria y Ciencia Aplicadas, Universidad Autonoma del Estado de Morelos, Av. Universidad 1001. Col. Chamilpa, C.P. 62209 Cuernavaca, Morelos (Mexico); Garcia-Valladares, O. [Centro de Investigacion en Energia (CIE), Universidad Nacional Autonoma de Mexico(UNAM), Privada Xochicalco S/N, Temixco, 62580 Morelos (Mexico)

    2009-07-15

    A predictive model is developed to describe heat transfer and fluid dynamic behavior of a helical double-pipe vertical evaporator used in an absorption heat transformer integrated to a water purification process. The evaporator uses water as working fluid connected in countercurrent. Heat transfer by conduction in the internal tube wall is considered; in addition the change of phase is carried out into the internal tube. The dynamic model considers equations of continuity, momentum and energy in each flow. The discretized governing equations are coupled using an implicit step by step method. The results of this model are compared with the experimental data in steady state, obtaining good agreement in the evaporation process. The model is also evaluated of form dynamic to determine the principal operation variables that affect the evaporator with the main objective to optimize and control the system. (author)

  13. Avoiding leakage flow-induced vibration by a tube-in-tube slip joint

    International Nuclear Information System (INIS)

    Mulcahy, T.M.

    1985-01-01

    Parameters and operating conditions (a stability map) were determined for which a specific slip-joint design did not cause self-excited lateral vibration of the two cantilevered, telescoping tubes forming the joint. The joint design featured a localized annular constriction. Flowrate, modal damping, tube engagement length, and eccentric positioning were among the parameters tested. Interestingly, all self-excited vibrations could be avoided by following a simple design rule: place constrictions only at the downstream end of the annular region between the tubes. Also, overall modal damping decreased with increased flowrate, at least initially, for upstream constrictions while the damping increased for downstream constrictions

  14. Structural and electronic properties of boron-doped double-walled silicon carbide nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Behzad, Somayeh, E-mail: somayeh.behzad@gmail.co [Physics Department, Faculty of Science, Razi University, Kermanshah (Iran, Islamic Republic of); Moradian, Rostam [Physics Department, Faculty of Science, Razi University, Kermanshah (Iran, Islamic Republic of); Nano Science and Technology Research Center, Razi University, Kermanshah (Iran, Islamic Republic of); Computational Physical Science Research Laboratory, Department of Nano Science, Institute for Studies in Theoretical Physics and Mathematics (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Chegel, Raad [Physics Department, Faculty of Science, Razi University, Kermanshah (Iran, Islamic Republic of)

    2010-12-01

    The effects of boron doping on the structural and electronic properties of (6,0)-(14,0) double-walled silicon carbide nanotube (DWSiCNT) are investigated by using spin-polarized density functional theory. It is found that boron atom could be more easily doped in the inner tube. Our calculations indicate that a Si site is favorable for B under C-rich condition and a C site is favorable under Si-rich condition. Additionally, B-substitution at either single carbon or silicon atom site in DWSiCNT could induce spontaneous magnetization.

  15. Structural and electronic properties of boron-doped double-walled silicon carbide nanotubes

    International Nuclear Information System (INIS)

    Behzad, Somayeh; Moradian, Rostam; Chegel, Raad

    2010-01-01

    The effects of boron doping on the structural and electronic properties of (6,0)-(14,0) double-walled silicon carbide nanotube (DWSiCNT) are investigated by using spin-polarized density functional theory. It is found that boron atom could be more easily doped in the inner tube. Our calculations indicate that a Si site is favorable for B under C-rich condition and a C site is favorable under Si-rich condition. Additionally, B-substitution at either single carbon or silicon atom site in DWSiCNT could induce spontaneous magnetization.

  16. Structural and electronic properties of boron-doped double-walled silicon carbide nanotubes

    Science.gov (United States)

    Behzad, Somayeh; Moradian, Rostam; Chegel, Raad

    2010-12-01

    The effects of boron doping on the structural and electronic properties of (6,0)@(14,0) double-walled silicon carbide nanotube (DWSiCNT) are investigated by using spin-polarized density functional theory. It is found that boron atom could be more easily doped in the inner tube. Our calculations indicate that a Si site is favorable for B under C-rich condition and a C site is favorable under Si-rich condition. Additionally, B-substitution at either single carbon or silicon atom site in DWSiCNT could induce spontaneous magnetization.

  17. Pyrotechnic Tubing Connector

    Science.gov (United States)

    Graves, Thomas J.; Yang, Robert A.

    1988-01-01

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

  18. Modelling the nonlinear behaviour of double walled carbon nanotube based resonator with curvature factors

    Science.gov (United States)

    Patel, Ajay M.; Joshi, Anand Y.

    2016-10-01

    This paper deals with the nonlinear vibration analysis of a double walled carbon nanotube based mass sensor with curvature factor or waviness, which is doubly clamped at a source and a drain. Nonlinear vibrational behaviour of a double-walled carbon nanotube excited harmonically near its primary resonance is considered. The double walled carbon nanotube is harmonically excited by the addition of an excitation force. The modelling involves stretching of the mid plane and damping as per phenomenon. The equation of motion involves four nonlinear terms for inner and outer tubes of DWCNT due to the curved geometry and the stretching of the central plane due to the boundary conditions. The vibrational behaviour of the double walled carbon nanotube with different surface deviations along its axis is analyzed in the context of the time response, Poincaré maps and Fast Fourier Transformation diagrams. The appearance of instability and chaos in the dynamic response is observed as the curvature factor on double walled carbon nanotube is changed. The phenomenon of Periodic doubling and intermittency are observed as the pathway to chaos. The regions of periodic, sub-harmonic and chaotic behaviour are clearly seen to be dependent on added mass and the curvature factors in the double walled carbon nanotube. Poincaré maps and frequency spectra are used to explicate and to demonstrate the miscellany of the system behaviour. With the increase in the curvature factor system excitations increases and results in an increase of the vibration amplitude with reduction in excitation frequency.

  19. SG tube identification

    International Nuclear Information System (INIS)

    Hoogstraten, P. van

    1994-01-01

    A ''Tracker'' system is described which is designed to identify any tube in a reactor steam generator quickly and safely. Occupational radiation doses to maintenance workers are reduced by using a Tracker and emergency down times are shortened. The system employs a television camera and light source in a stainless steel box with a large window. Both the camera and spotlight can be panned and tilted to reach any point on the tubesheet and are remotely controlled. An operator at a safe working distance can identify any tube visible on a real time video by comparison with the tubesheet pattern stored earlier in the computer memory. The identified tube can then be spotlighted and dealt with quickly by a maintenance worker inside the channel head. (UK)

  20. Numerical simulation of tubes-in-tube heat exchanger in a mixed refrigerant Joule-Thomson cryocooler

    Science.gov (United States)

    Damle, R. M.; Ardhapurkar, P. M.; Atrey, M. D.

    2017-02-01

    Mixed refrigerant Joule-Thomson (MRJT) cryocoolers can produce cryogenic temperatures with high efficiency and low operating pressures. As compared to the high system pressures of around 150-200 bar with nitrogen, the operational pressures with non-azeotropic mixtures (e.g., nitrogen-hydrocarbons) come down to 10-25 bar. With mixtures, the heat transfer in the recuperative heat exchanger takes place in the two-phase region. The simultaneous boiling and condensation of the cold and hot gas streams lead to higher heat transfer coefficients as compared to single phase heat exchange. The two-phase heat transfer in the recuperative heat exchanger drastically affects the performance of a MRJT cryocooler. In this work, a previously reported numerical model for a simple tube-in-tube heat exchanger is extended to a multi tubes-in-tube heat exchanger with a transient formulation. Additionally, the J-T expansion process is also considered to simulate the cooling process of the heat exchanger from ambient temperature conditions. A tubes-in-tube heat exchanger offers more heat transfer area per unit volume resulting in a compact design. Also, the division of flow in multiple tubes reduces the pressure drop in the heat exchanger. Simulations with different mixtures of nitrogen-hydrocarbons are carried out and the numerical results are compared with the experimental data.

  1. Improper tube fixation causing a leaky cuff

    Directory of Open Access Journals (Sweden)

    Gupta Babita

    2010-01-01

    Full Text Available Leaking endotracheal tube cuffs are common problems in intensive care units. We report a case wherein the inflation tube was damaged by the adhesive plaster used for tube fixation and resulted in leaking endotracheal tube cuff. We also give some suggestions regarding the tube fixation and some remedial measures for damaged inflation system.

  2. 100-ps framing-camera tube

    International Nuclear Information System (INIS)

    Kalibjian, R.

    1978-01-01

    The optoelectronic framing-camera tube described is capable of recording two-dimensional image frames with high spatial resolution in the <100-ps range. Framing is performed by streaking a two-dimensional electron image across narrow slits. The resulting dissected electron line images from the slits are restored into framed images by a restorer deflector operating synchronously with the dissector deflector. The number of framed images on the tube's viewing screen equals the number of dissecting slits in the tube. Performance has been demonstrated in a prototype tube by recording 135-ps-duration framed images of 2.5-mm patterns at the cathode. The limitation in the framing speed is in the external drivers for the deflectors and not in the tube design characteristics. Faster frame speeds in the <100-ps range can be obtained by use of faster deflection drivers

  3. Když se řekne YouTube

    OpenAIRE

    Voců, Ondřej

    2011-01-01

    This article describes basic characteristics of YouTube portal, explains its importance and provided services. The first part of this article is applied to basic characteristics of YouTube portal, the second part deals with processes related to videos on YouTube. YouTube users, YouTube partners and projects are mainspring of the third part of this article. Special subchapter outlines possibilites of YouTube in relation to information studies and librarianship. At the end of the fourth chapter...

  4. Water-storage-tube systems. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hemker, P.

    1981-12-24

    Passive solar collection/storage/distribution systems were surveyed, designed, fabricated, and mechanically and thermally tested. The types studied were clear and opaque fiberglass tubes, metal tubes with plastic liners, and thermosyphoning tubes. (MHR)

  5. Preparation of metallic uranium tubes; Elaboration des tubes d'uranium metallique

    Energy Technology Data Exchange (ETDEWEB)

    Lerouge, G; Decours, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    The production furnace is an induction heated vacuum furnace having a capacity at the moment of 250 kg. Previously the crucible was heated by the inductor, the mould being outside the inductor. The tubes thus produced contained cavities, the alloy structure was fine; this was cold-mould casting, At the moment the top of the moulds are pre-heated, this is the so called hot-mould casting. This method has the advantage of eliminating the cavities but leads to a less fine microstructure. The alloy used for the 18 x 40 mm and 23 x 43 mm tubes is U-Mo (1.1 per cent). Since the moulds are now heated at the top, the solidification of the metal is very slow in this zone leading to a pronounced {gamma} grain, whereas towards the base the faster cooling leads to a smaller {gamma} grain. The {gamma} structure depends essentially on the solidification rate and on the time spent in this zone. In order to obtain a fine and homogeneous grain along the whole length of the tube, a controlled cooling treatment is effected. It consists in heating the uranium tubes in the {gamma} place and then in cooling them at a rate of between 20 and 50 deg C/mm down to 400 deg C. The 77 x 95 mm and 54 x 70 mm annular elements are at the moment being produced for research purposes. Their preparation is similar to that of 18 x 40 mm and 23 x 43 mm elements. The 77 x 95 mm tubes are at the moment made from U-Cr alloy (0.1 per cent); because of their size, their preparation is carried out in 600 mm diameter furnaces. (authors) [French] Le four d'elaboration est un four sous vide chaufffe par induction, dont la capacite actuelle est de 250 kg. Anterieurement le creuset seul etait chauffe par l'inducteur, les moules etaient hors de l'inducteur. Les tubes obtenus presentaient des cavites, la structure de l'alliage etait fine, c'etait la coulee en moules froids. Actuellement on prechauffe le haut des moules, c'est la coulee dite en moules chauds. Cette facon de faire a l'avantage de supprimer les cavites

  6. Usefulness of extracorporeal membrane oxygenation using double roller pumps in a low body weight newborn: A novel strategy for mechanical circulatory support in an infant

    Directory of Open Access Journals (Sweden)

    Keisuke Nakanishi

    2016-01-01

    Full Text Available Extracorporeal membrane oxygenation (ECMO with a centrifugal pump requires a certain flow rate; therefore, its application for low body weight infants is frequently accompanied by oxygenator membrane malfunction and/or inadequate perfusion. To prevent low-flow associated complications, we report a case in which a novel system of dual roller pumps was used. A baby girl with a body mass index 0.25 m 2 , who experienced difficulty weaning from cardiopulmonary bypass after a Norwood-like operation, required an ECMO. Concerns for the tube lifespan reduction due to roller pump friction led to the use of a double roller pump circulation. The termination of ECMO during tube exchange is not needed, because circulation is maintained by another roller pump. The novel strategy of ECMO with double roller pumps will allow low perfusion rate to provide adequate circulatory support for low body weight patients.

  7. Gastroenteric tube feeding: Techniques, problems and solutions

    Science.gov (United States)

    Blumenstein, Irina; Shastri, Yogesh M; Stein, Jürgen

    2014-01-01

    Gastroenteric tube feeding plays a major role in the management of patients with poor voluntary intake, chronic neurological or mechanical dysphagia or gut dysfunction, and patients who are critically ill. However, despite the benefits and widespread use of enteral tube feeding, some patients experience complications. This review aims to discuss and compare current knowledge regarding the clinical application of enteral tube feeding, together with associated complications and special aspects. We conducted an extensive literature search on PubMed, Embase and Medline using index terms relating to enteral access, enteral feeding/nutrition, tube feeding, percutaneous endoscopic gastrostomy/jejunostomy, endoscopic nasoenteric tube, nasogastric tube, and refeeding syndrome. The literature showed common routes of enteral access to include nasoenteral tube, gastrostomy and jejunostomy, while complications fall into four major categories: mechanical, e.g., tube blockage or removal; gastrointestinal, e.g., diarrhea; infectious e.g., aspiration pneumonia, tube site infection; and metabolic, e.g., refeeding syndrome, hyperglycemia. Although the type and frequency of complications arising from tube feeding vary considerably according to the chosen access route, gastrointestinal complications are without doubt the most common. Complications associated with enteral tube feeding can be reduced by careful observance of guidelines, including those related to food composition, administration rate, portion size, food temperature and patient supervision. PMID:25024606

  8. An advanced tube wear and fatigue workstation to predict flow induced vibrations of steam generator tubes

    International Nuclear Information System (INIS)

    Gay, N.; Baratte, C.; Flesch, B.

    1997-01-01

    Flow induced tube vibration damage is a major concern for designers and operators of nuclear power plant steam generators (SG). The operating flow-induced vibrational behaviour has to be estimated accurately to allow a precise evaluation of the new safety margins in order to optimize the maintenance policy. For this purpose, an industrial 'Tube Wear and Fatigue Workstation', called 'GEVIBUS Workstation' and based on an advanced methodology for predictive analysis of flow-induced vibration of tube bundles subject to cross-flow has been developed at Electricite de France. The GEVIBUS Workstation is an interactive processor linking modules as: thermalhydraulic computation, parametric finite element builder, interface between finite element model, thermalhydraulic code and vibratory response computations, refining modelling of fluid-elastic and random forces, linear and non-linear dynamic response and the coupled fluid-structure system, evaluation of tube damage due to fatigue and wear, graphical outputs. Two practical applications are also presented in the paper; the first simulation refers to an experimental set-up consisting of a straight tube bundle subject to water cross-flow, while the second one deals with an industrial configuration which has been observed in some operating steam generators i.e., top tube support plate degradation. In the first case the GEVIBUS predictions in terms of tube displacement time histories and phase planes have been found in very good agreement with experiment. In the second application the GEVIBUS computation showed that a tube with localized degradation is much more stable than a tube located in an extended degradation zone. Important conclusions are also drawn concerning maintenance. (author)

  9. Tubing crimping pliers

    Science.gov (United States)

    Lindholm, G.T.

    1981-02-27

    The disclosure relates to pliers and more particularly to pliers for crimping two or more pieces of copper tubing together prior to their being permanently joined by brazing, soldering or the like. A die containing spring-loaded pins rotates within a cammed ring in the head of the pliers. As the die rotates, the pins force a crimp on tubing held within the pliers.

  10. Tube Length and Water Flow

    Directory of Open Access Journals (Sweden)

    Ben Ruktantichoke

    2011-06-01

    Full Text Available In this study water flowed through a straight horizontal plastic tube placed at the bottom of a large tank of water. The effect of changing the length of tubing on the velocity of flow was investigated. It was found that the Hagen-Poiseuille Equation is valid when the effect of water entering the tube is accounted for.

  11. The structural and electronic properties of monovalent sidewall functionalized double-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Jalili, Seifollah; Jamali, Maryam

    2012-01-01

    Highlights: ► (6,0)-(13,0) DWCNT, built from (6,0) and (13,0) SWCNTs, is a metallic nanotubes. ► NH 2 /(6,0)-(13,0) and COOH/(6,0)-(13,0) is semimetal and semiconductor, respectively. ► In NH 2 /(6,0)-(13,0) electrons transferred mainly from inner tube to NH 2 group. - Abstract: The structural and electronic properties of (6,0)-(13,0) double-walled carbon nanotubes (DWCNTs) and monovalent sidewall functionalized DWCNTs with –NH 2 and –COOH groups were studied using density functional theory. The results show that pure (6,0)-(13,0) DWCNTs are metallic. However, by functionalizing a DWCNT, local distortions are induced in the outer tube sidewall along the radial direction. The resulting structures, NH 2 /(6,0)-(13,0) and COOH/(6,0)-(13,0) DWCNTs, exhibit significant structural changes, and are semimetal with no energy gap and semiconducting with a small energy gap, respectively. In NH 2 /(6,0)-(13,0) DWCNTs, new electronic states are created and distributed on the outer wall and NH 2 group by electron transfer from the inner tube to the NH 2 group. In COOH/(6,0)-(13,0) DWCNTs, new states are created and distributed on the inner wall, but there is insignificant charge transfer between the inner tube and the COOH group. These results confirm that local atomic structural distortion on DWCNTs caused by sidewall functionalization can modify the electronic structures of DWCNTs.

  12. Boiling heat transfer on horizontal tube bundles

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    Nucleate boiling heat transfer characteristics for a tube in a bundle differ from that for a single tube in a pool and this difference is known as 'tube bundle effect.' There exist two bundle effects, positive and negative. The positive bundle effect enhances heat transfer due to convective flow induced by rising bubbles generated from the lower tubes, while the negative bundle effect deteriorates heat transfer due to vapor blanketing caused by accumulation of bubbles. Staggered tube bundles tested and found that the upper tubes in bundles have higher heat transfer coefficients than the lower tubes. The effects of various parameters such as pressure, tube geometry and oil contamination on heat transfer have been examined. Some workers attempted to clarify the mechanism of occurrence of 'bundle effect' by testing tube arrangements of small scale. All reported only enhancement in heat transfer but results showed the symptom of heat transfer deterioration at higher heat fluxes. As mentioned above, it has not been clarified so far even whether the 'tube bundle effect' should serve as enhancement or deterioration of heat transfer in nucleate boiling. In this study, experiments are performed in detail by using bundles of small scale, and effects of heat flux distribution, pressure and tube location are clarified. Furthermore, some consideration on the mechanisms of occurrence of 'tube bundle effect' is made and a method for prediction of heat transfer rate is proposed

  13. N Reactor pressure tube 1350 postirradiation examination

    International Nuclear Information System (INIS)

    Cook, D.J.

    1977-01-01

    The N Reactor pressure tubes were fabricated from Zircaloy-2 primarily due to the excellent corrosion resistance, low neutron absorption, and high strength properties of this alloy. Irradiation damage mechanisms increase the strength and decrease the ductility of the Zircaloy-2. Irradiation data available at the time the tubes were installed indicated that fast neutron irradiation damage mechanisms would not decrease the ductility to unacceptable levels over the estimated plant life of 25 to 30 years. However, because the tubes are a primary coolant system component and only limited data are available on irradiation effects at high fluences, a Postirradiation Examination (PIE) program was developed to assure that service factors do not compromise pressure tube integrity essential to reactor safety. The PIE program requires that a pressure tube be periodically removed from the reactor for destructive testing. The N Reactor Technical Specifications specify that the frequency of pressure tube removal and examination be based upon the previous PIE test results. Four pressure tubes were examined before tube 1350, and the test results were summarized in individual reports. PIE results on tube 1350 were summarized along with the test results on the previous four tubes in a previous report. The purpose of this report is to present in detail the results on PIE of pressure tube 1350, and, in particular, document the technique by which the fracture toughness of the pressure tube was determined

  14. Distribution of volatile and non volatile elements in grain-size fractions of Apollo 17 drive tube 74001/2

    International Nuclear Information System (INIS)

    Kraehenbuehl, U.

    1980-01-01

    A study of four samples of double drive tube 74001/2 originating from 12, 25, 38, and 58 cm depths indicates that the concentrations of major and nonvolatile elements are fairly uniform for the four layers and the individual size fractions, while volatile elements as well as Au and Ir are enriched in the smaller grain-size fractions. It is concluded from the measured Au/Ir ratios and from the absence of a surface enrichment of Co that the material in the drive tube 74001/2 is not the result of an impact of an iron meteorite into a lava lake, but originated in at least three volcanic eruptions. No indication of a later disturbance of the stratigraphy of the layers is observed. Exposure ages of 345,000 and 225,000 years result from Ir deposits for the two layers of 74002

  15. Contrastive Analysis and Research on Negative Pressure Beam Tube System and Positive Pressure Beam Tube System for Mine Use

    Science.gov (United States)

    Wang, Xinyi; Shen, Jialong; Liu, Xinbo

    2018-01-01

    Against the technical defects of universally applicable beam tube monitoring system at present, such as air suction in the beam tube, line clogging, long sampling time, etc., the paper analyzes the current situation of the spontaneous combustion fire disaster forecast of mine in our country and these defects one by one. On this basis, the paper proposes a research thought that improving the positive pressure beam tube so as to substitute the negative pressure beam tube. Then, the paper introduces the beam tube monitoring system based on positive pressure technology through theoretical analysis and experiment. In the comparison with negative pressure beam tube, the paper concludes the advantage of the new system and draws the conclusion that the positive pressure beam tube is superior to the negative pressure beam tube system both in test result and test time. At last, the paper proposes prospect of the beam tube monitoring system based on positive pressure technology.

  16. 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.

  17. Nasogastric tube versus gastrostomy tube for gastric decompression in abdominal surgery: a prospective, randomized trial comparing patients' tube-related inconvenience.

    Science.gov (United States)

    Hoffmann, S; Koller, M; Plaul, U; Stinner, B; Gerdes, B; Lorenz, W; Rothmund, M

    2001-11-01

    Perioperative decompression of the stomach is still a common procedure and can be achieved using either nasogastric tubes (NTs) or gastrostomy tubes (GTs). While both procedures appear to be equally effective, some authors believe that NTs are less convenient for patients than GTs. However, to date, no reliable prospective data are available on this issue. We conducted a prospective, randomized trial comparing NTs versus GTs with a total of 110 patients undergoing elective colon surgery. The primary outcome measure was the patient's tube-related inconvenience and pain, assessed in a standardized interview on day 2 after surgery and quantified by means of a visual-analog scale (VAS). A questionnaire including the EORTC QLQ-C30 and additional items regarding retrospective tube-related judgements was administered on the day of discharge and 4 weeks after discharge. Secondary endpoints were the therapy-related morbidity and general complications. When patients were asked which of their drainage tubes (all patients had three or four drainage tubes, such as decompression drains, urinary drains, central venous line) was most inconvenient, 43% (CI 33-53%) in the NT group reported that the NT was most inconvenient, while only 4% (CI 1-10%) of the GT patients judged the GT most inconvenient ( Ptube system (day 2 p.o.: 71%, CI 61-80%; 4 weeks p.o.: 66%, CI 56-75%) than did GT patients (day 2 p.o.: 94%, CI 88-98%; 4 weeks p.o.: 91% CI 84-96%); again, these differences were statistically significant ( Ptube system have to weigh up the possibilities of different averse clinical as well as subjective outcomes. It is then preferable to include patients' preferences in the individual decision making process (shared-decision making).

  18. Numerical investigation of heat transfer in annulus laminar flow of multi tubes-in-tube helical coil

    Science.gov (United States)

    Nada, S. A.; Elattar, H. F.; Fouda, A.; Refaey, H. A.

    2018-03-01

    In the present study, a CFD analysis using ANSYS-FLUENT 14.5 CFD package is used to investigate the characteristics of heat transfer of laminar flow in annulus formed by multi tubes in tube helically coiled heat exchanger. The numerical results are validated by comparison with previous experimental data and fair agreements were existed. The influences of the design and operation parameters such as heat flux, Reynolds numbers and annulus geometry on the heat transfer characteristics are investigated. Different annulus of different numbers of inner tubes, specifically 1, 2, 3, 4 and 5 tubes, are tested. The Results showed that for all the studied annulus, the heat flux has no effect on the Nusselt number and compactness parameter. The annulus formed by using five inner tubes showed the best heat transfer performance and compactness parameter. Correlation of predicting Nusselt number in terms of Reynolds number and number of inner tubes are presented.

  19. YouTube and ‘psychiatry’

    Science.gov (United States)

    Gordon, Robert; Miller, John; Collins, Noel

    2015-01-01

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

  20. 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)

  1. 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.

  2. Vibration characteristics of tubes in a heat exchanger

    International Nuclear Information System (INIS)

    Simonis; Steininger, D.

    1985-01-01

    Circumferential tube cracking has occurred in the once-through steam generators used in nuclear power plants. Analyses of failed tubes indicate that a fatigue process induced by tube vibration could cause the leaks. To investigate the vibration amplitude of tube spans during reactor operation, twenty-three tube spans were instrumented with accelerometers and strain gages at Three Mile Island Unit 2. To aid in the interpretation of the operational vibration measurements, tests were performed, in air, to determine the predominant resonant frequencies and mode shapes of selected tubes. By adapting modal analysis techniques, the two predominant response frequencies were determined for 100 randomly selected tube spans and the 23 instrumented tube spans; plus, the predominant mode shape was determined for five tube spans bounded by the tube sheet and the fifteenth support plate and one tube span bounded by the ninth and tenth support plate. The average value for the first and second predominant response frequency was 65 Hz and 170 Hz, respectively. The predominant frequencies for the individual tube spans are distributed randomly with no spatial orientation. The first predominant mode shape for the six tube spans tested corresponded to a classical beam with elastic supports. The equivalent stiffness of the elastic supports depend upon the tube span tested

  3. Experiment data report for Semiscale Mod-1 Test S-28-1 (steam generator tube rupture test series)

    International Nuclear Information System (INIS)

    Collins, B.L.; Coppin, C.E.; Sackett, K.E.

    1977-10-01

    Recorded test data are presented for Test S-28-1 of the Semiscale Mod-1 steam generator tube rupture test series. These tests are among several Semiscale Mod-1 experiments conducted to investigate the thermal and hydraulic phenomena accompanying a hypothesized loss-of-coolant accident in a pressurized water reactor (PWR) system. Test S-28-1 was conducted from initial conditions of 15 767 kPa and 557 K to investigate the response of the Semiscale Mod-1 system to a depressurization and reflood transient following a simulated double-ended offset shear of the broken loop cold leg piping. During the test, cooling water was injected into the cold leg of the intact and broken loops to simulate emergency core coolant injection in a PWR. Sixty steam generator tube ruptures were simulated by a controlled injection from a heated accumulator into the intact loop hot leg

  4. Method of repairing pressure tube type reactors

    International Nuclear Information System (INIS)

    Asada, Takashi.

    1983-01-01

    Purpose: To enable to re-start the reactor operation in a short time, upon occurrence of failures in a pressure tube, as well as directly examine the cause for the failures in the pressure tube. Method: The pressure tube reactor main body comprises a calandria tank of a briquette form, pressure tubes, fuel assemblies and an iron-water shielding body. If failure is resulted to a pressure tube, the reactor operation is at first shutdown and nuclear fuel assemblies are extracted to withdraw from the pressure tube. Then, to an inlet pipe way and an outlet pipeway connected to the failed pressure tube, are attached plugs by means of welding or the like at the appropriate position where the radiation exposure dose is lower and the repairing work can be performed with ease. The pressure tube is disconnected to withdraw from the inlet pipeway and the outlet pipeway and, instead, radiation shielding plug tube is inserted and shield cooling device is actuated if required, wherein the reactor is actuated to re-start the operation. (Yoshino, Y.)

  5. Practical acoustic thermometry with twin-tube and single-tube sensors

    Energy Technology Data Exchange (ETDEWEB)

    De Podesta, M.; Sutton, G.; Edwards, G.; Stanger, L.; Preece, H. [National Physical Laboratory, Teddington, (United Kingdom)

    2015-07-01

    Accurate measurement of high temperatures in a nuclear environment presents unique challenges. All secondary techniques inevitably drift because the thermometric materials in thermocouples and resistance sensors are sensitive not just to temperature, but also their own chemical and physical composition. The solution is to use primary methods that rely on fundamental links between measurable physical properties and temperature. In the nuclear field the best known technique is the measurement of Johnson Noise in a resistor (See Paper 80 at this conference). In this paper we describe the measurement of temperature in terms of the speed of sound in a gas confined in a tube - an acoustic waveguide. Acoustic thermometry is the most accurate technique of primary thermometry ever devised with the best uncertainty of measurement below 0.001 C. In contrast, the acoustic technique described in this work has a much larger uncertainty, approximately 1 deg. C. But the cost and ease of use are improved by several orders of magnitude, making implementation eminently practical. We first describe the basic construction and method of operation of thermometers using twin-tubes and single tubes. We then present results using a twin-tube design showing that showing long term stability (i.e. no detectable drift) at 700 deg. C over periods of several weeks. We then outline how the technique may be developed for different nuclear applications. (authors)

  6. Investigating the efficacy of magnetic nanofluid as a coolant in double-pipe heat exchanger in the presence of magnetic field

    International Nuclear Information System (INIS)

    Bahiraei, Mehdi; Hangi, Morteza

    2013-01-01

    Highlights: • Efficacy of magnetic nanofluid as coolant was studied in double-pipe heat exchanger. • Effect of applying quadrupole magnetic field with different magnitudes was analyzed. • Magnetic force makes the concentration distribution more uniform in tube side. • Applying magnetic field enhances both pressure drop and heat transfer. • Optimization was performed to reach maximum heat transfer and minimum pressure drop. - Abstract: The current study attempts to investigate the performance of water based Mn–Zn ferrite magnetic nanofluid in a counter-flow double-pipe heat exchanger under quadrupole magnetic field using the two-phase Euler–Lagrange method. The nanofluid flows in the tube side as coolant, while the hot water flows in the annulus side. The effects of different parameters including concentration, size of the particles, magnitude of the magnetic field and Reynolds number are examined. Distribution of the particles is non-uniform at the cross section of the tube such that the concentration is higher at central regions of the tube. Application of the magnetic field makes the distribution of particles more uniform and this uniformity increases by increasing the distance from the tube inlet. Increasing each of the parameters of concentration, particle size and magnitude of the magnetic field will lead to a greater pressure drop and also higher heat transfer improvement. At higher Reynolds numbers, the effect of magnetic force is diminished. Optimization was performed using genetic algorithm coupled with compromise programming technique in order to reach the maximum overall heat transfer coefficient along with the minimum pressure drop. For this purpose, the models of objective functions of overall heat transfer coefficient and pressure drop of the nanofluid were first extracted in terms of the effective parameters using neural network. The neural network model predicts the output variables with a very good accuracy. The optimal values were

  7. Preliminary evaluation of steam generator tube rupture (SGTR) accident in lead cooled reactor

    International Nuclear Information System (INIS)

    Frano, R. Lo; Forasassi, G.

    2009-01-01

    In this paper some contributions are provided to the development of a European Lead-cooled System, known as the ELSY project (within EU-6 Framework Project); that will constitute a possible reference system for a large lead-cooled reactor of GEN IV. Steam generator (SG) tubing of this system type might be subject to a variety of degradation processes, such as cracking, wall thinning and potential leakage or rupture, eventually leading to the failure of one or more SG tubes that constitute a steam generator tube rupture (SGTR) accident with possible consequences for the safety of the primary systems. It is therefore of interest for the designer to know how the SG itself, as well as the vessel and internals structures, behave under impulsive loading conditions (in form of a rapid and strong increase of pressure) that can arise as consequences of the interaction between the primary and secondary coolants (lead-water interaction). The analysed initiator event, as already mentioned, is a large break (up to a double ended guillotine break) of one (or more) SG cooling tubes that may become severe enough to determine dangerous effects on the interested structures. In order to better simulate and perform the mentioned postulated SGTR accident sequence analyses, an appropriate numerical model with the available computing resources (FEM codes) was set up at the DIMNP of Pisa University. That model was used to evaluate the effects of the propagation of the blast pressure waves inside the SG structures, taking into account also the sloshing phenomenon that could be induced by the lead primary coolant motions. Therefore the SGTR effects study may be considered as a transient and non linear problem the solution of which provides the 'time histories' of hydrodynamic pressures and stresses on the reactor pressure vessel and internals walls. (author)

  8. Ac-induced disruption of the doubleDs structure in tomato

    NARCIS (Netherlands)

    Rommens, Caius M.T.; Biezen, Erik A. van der; Ouwerkerk, Pieter B.F.; Nijkamp, H. John J.; Hille, Jacques

    1991-01-01

    The maize doubleDs element is stably maintained in the tomato genome. Upon the subsequent introduction of Ac into a plant containing doubleDs, disruption of the doubleDs structure and DNA rearrangements at the site of the doubleDs element were observed. No indications were obtained for excision of

  9. Ultra-fast framing camera tube

    Science.gov (United States)

    Kalibjian, Ralph

    1981-01-01

    An electronic framing camera tube features focal plane image dissection and synchronized restoration of the dissected electron line images to form two-dimensional framed images. Ultra-fast framing is performed by first streaking a two-dimensional electron image across a narrow slit, thereby dissecting the two-dimensional electron image into sequential electron line images. The dissected electron line images are then restored into a framed image by a restorer deflector operated synchronously with the dissector deflector. The number of framed images on the tube's viewing screen is equal to the number of dissecting slits in the tube. The distinguishing features of this ultra-fast framing camera tube are the focal plane dissecting slits, and the synchronously-operated restorer deflector which restores the dissected electron line images into a two-dimensional framed image. The framing camera tube can produce image frames having high spatial resolution of optical events in the sub-100 picosecond range.

  10. High temperature ceramic-tubed reformer

    Science.gov (United States)

    Williams, Joseph J.; Rosenberg, Robert A.; McDonough, Lane J.

    1990-03-01

    The overall objective of the HiPHES project is to develop an advanced high-pressure heat exchanger for a convective steam/methane reformer. The HiPHES steam/methane reformer is a convective, shell and tube type, catalytic reactor. The use of ceramic tubes will allow reaction temperature higher than the current state-of-the-art outlet temperatures of about 1600 F using metal tubes. Higher reaction temperatures increase feedstock conversion to synthesis gas and reduce energy requirements compared to currently available radiant-box type reformers using metal tubes. Reforming of natural gas is the principal method used to produce synthesis gas (primarily hydrogen and carbon monoxide, H2 and CO) which is used to produce hydrogen (for refinery upgrading), methanol, as well as several other important materials. The HiPHES reformer development is an extension of Stone and Webster's efforts to develop a metal-tubed convective reformer integrated with a gas turbine cycle.

  11. Physics of magnetic flux tubes

    CERN Document Server

    Ryutova, Margarita

    2015-01-01

    This book is the first account of the physics of magnetic flux tubes from their fundamental properties to collective phenomena in an ensembles of flux tubes. The physics of magnetic flux tubes is absolutely vital for understanding fundamental physical processes in the solar atmosphere shaped and governed by magnetic fields. High-resolution and high cadence observations from recent space and  ground-based instruments taken simultaneously at different heights and temperatures not only show the ubiquity of filamentary structure formation but also allow to study how various events are interconnected by system of magnetic flux tubes. The book covers both theory and observations. Theoretical models presented in analytical and phenomenological forms are tailored for practical applications. These are welded with state-of-the-art observations from early decisive ones to the most recent data that open a new phase-space for exploring the Sun and sun-like stars. Concept of magnetic flux tubes is central to various magn...

  12. Demonstration for the Applicability of the EPRI ETSS on the SG Tube Wear Defects Formed at the Tube Support Structure

    International Nuclear Information System (INIS)

    Shin, Ki Seok; Cheon, Keun Young; Nam, Min Woo; Min, Kyong Mahn

    2013-01-01

    In this paper, the authorized EPRI ETSS 27906.2 applied to the detection of tapered wear volumetric indications and depth sizing within the free span area, loose part not present was reviewed and applied to the site SG tubes for getting the actual value of the wear depth and providing structural integrity interpretation based on engineering evaluation. The experiment to demonstrate the applicability of EPRI ETSS was performed by the employment of the newly prepared STD tube and resulted in ensuring the effectiveness and equivalency of the EPRI ETSS as well. The authorized EPRI ETSS 27906.2 for getting the actual value of the wear depth and providing structural integrity interpretation based on engineering evaluation was reviewed and applied to the site SG tubes. The testing results were reviewed with the influences of SG tube material and the support structure. The impact of the tube materials was insignificant and that of the tube support structure showed somewhat conservative results. The testing resulted in successful demonstration of applicability of the EPRI ETSS on the SG tube wear defects at the tube support. One of the major flaw mechanisms detected in the currently operating domestic OPR-1000 pressurized water reactors(PWR's) steam generator(SG) tubes is wear defect. In general, wear defect has been constantly detected in the upper tube bundle imposed to the flow induced vibration interaction between tube and its support structure, and the quantity of the affected tubes has also shown the tendency to increase as plant operation life is added. In order to take appropriate measures and maintain the structural integrity for the SG tubes, wear defect is currently categorized as active damage mechanism and the tubes containing 40% or greater wear depth of the nominal tube wall thickness shall be plugged per SGMP(SG Management Program) Recently, a fairly large amplitude of wear defects on the Batwing(BW), one of the upper tube support structures in the SG tubes

  13. Demonstration for the Applicability of the EPRI ETSS on the SG Tube Wear Defects Formed at the Tube Support Structure

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Ki Seok; Cheon, Keun Young; Nam, Min Woo [Korea Hydro and Nuclear Power Co. Ltd, Daejeon (Korea, Republic of); Min, Kyong Mahn [Universal Monitoring and Inspection Inc., Daejeon (Korea, Republic of)

    2013-10-15

    In this paper, the authorized EPRI ETSS 27906.2 applied to the detection of tapered wear volumetric indications and depth sizing within the free span area, loose part not present was reviewed and applied to the site SG tubes for getting the actual value of the wear depth and providing structural integrity interpretation based on engineering evaluation. The experiment to demonstrate the applicability of EPRI ETSS was performed by the employment of the newly prepared STD tube and resulted in ensuring the effectiveness and equivalency of the EPRI ETSS as well. The authorized EPRI ETSS 27906.2 for getting the actual value of the wear depth and providing structural integrity interpretation based on engineering evaluation was reviewed and applied to the site SG tubes. The testing results were reviewed with the influences of SG tube material and the support structure. The impact of the tube materials was insignificant and that of the tube support structure showed somewhat conservative results. The testing resulted in successful demonstration of applicability of the EPRI ETSS on the SG tube wear defects at the tube support. One of the major flaw mechanisms detected in the currently operating domestic OPR-1000 pressurized water reactors(PWR's) steam generator(SG) tubes is wear defect. In general, wear defect has been constantly detected in the upper tube bundle imposed to the flow induced vibration interaction between tube and its support structure, and the quantity of the affected tubes has also shown the tendency to increase as plant operation life is added. In order to take appropriate measures and maintain the structural integrity for the SG tubes, wear defect is currently categorized as active damage mechanism and the tubes containing 40% or greater wear depth of the nominal tube wall thickness shall be plugged per SGMP(SG Management Program) Recently, a fairly large amplitude of wear defects on the Batwing(BW), one of the upper tube support structures in the SG

  14. Development, prevention, and treatment of feeding tube dependency.

    Science.gov (United States)

    Krom, Hilde; de Winter, J Peter; Kindermann, Angelika

    2017-06-01

    Enteral nutrition is effective in ensuring nutritional requirements and growth. However, when tube feeding lasts for a longer period, it can lead to tube dependency in the absence of medical reasons for continuation of tube feeding. Tube-dependent children are unable or refuse to start oral activities and they lack oral skills. Tube dependency has health-, psychosocial-, and economy-related consequences. Therefore, the transition to oral feeding is of great importance. However, this transition can be very difficult and needs a multidisciplinary approach. Most studies for treatment of tube dependency are based on behavioral interventions, such as family therapy, individual behavior therapy, neuro-linguistic programming, and parental anxiety reduction. Furthermore, oral motor therapy and nutritional adjustments can be helpful in tube weaning. The use of medication has been described in the literature. Although mostly chosen as the last resort, hunger-inducing methods, such as the Graz-model and the Dutch clinical hunger provocation program, are also successful in weaning children off tube feeding. The transition from tube to oral feeding is important in tube-dependent children but can be difficult. We present an overview for the prevention and treatment of tube dependency. What is known: • Longer periods of tube feeding can lead to tube dependency. • Tube weaning can be very difficult. What is new: • Weaning as soon as possible and therefore referral to a multidisciplinary team are recommended. • An overview of treatment options for tube dependency is presented in this article.

  15. Flaming on YouTube

    NARCIS (Netherlands)

    Moor, Peter J.; Heuvelman, A.; Verleur, R.

    2010-01-01

    In this explorative study, flaming on YouTube was studied using surveys of YouTube users. Flaming is defined as displaying hostility by insulting, swearing or using otherwise offensive language. Three general conclusions were drawn. First, although many users said that they themselves do not flame,

  16. 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

  17. Flow-induced decentering and tube support interaction for steam generator tubes: experiment and physical interpretation

    International Nuclear Information System (INIS)

    Gay, N.; Granger, S.

    1992-11-01

    Maintaining PWR components under reliable operating conditions requires a complex design to prevent various damaging processes including flow-induced vibration and wear mechanisms. To improve the prediction of tube/support interaction and wear in PWR components, EDF has undertaken a comprehensive program oriented to both experimental and computational studies. The present paper illustrates one aspect of this program, related to the determination of contact forces between steam generator tubes and anti-vibration bars (AVBs). The dynamic, nonlinear behavior of a U-tube excited by an air cross-flow is investigated on the CLAVECIN experiment. Interesting and rather unexpected results have been obtained, by varying clearances and flow velocities. The paper is focused on four main points: (i) the originality of the experiment with a force measurement device located in flow; (ii) the importance of a refined data processing for accurately measuring contact forces; (iii) the presentation of the unexpected phenomena revealed in the CLAVECIN experiment, i.e. a flow-induced decentering of the tube which changed the initial tube/AVB clearance, and the consequences on tube/support interaction; (iv) the influence of the actual tube/support clearance in flow on wear mechanisms. The work, presented in the second part of this paper, concentrates exclusively on the physical interpretation of the flow-induced decentering phenomenon and on the theoretical analysis of its consequences on dynamic tube/support interaction. We show that the flow-induced decentering phenomenon can be generated by an unstable quasi-static coupling between the flexible tube and the confined flow, in the vicinity of the support system. This phenomenon is not specific to the CLAVECIN tests and it can be expected every time that a movable obstacle is subjected to confined flow. Moreover, in single-sided impacting conditions, the theoretical analysis confirms the linear relation, found in the CLAVECIN tests

  18. Models for Automated Tube Performance Calculations

    International Nuclear Information System (INIS)

    Brunkhorst, C.

    2002-01-01

    High power radio-frequency systems, as typically used in fusion research devices, utilize vacuum tubes. Evaluation of vacuum tube performance involves data taken from tube operating curves. The acquisition of data from such graphical sources is a tedious process. A simple modeling method is presented that will provide values of tube currents for a given set of element voltages. These models may be used as subroutines in iterative solutions of amplifier operating conditions for a specific loading impedance

  19. PROBLEMS IN THE TUBING/PACKER SYSTEM

    OpenAIRE

    Davorin Matanović; Mario Livaja

    1993-01-01

    When gas and oil wells are completed and produced or treated through the tubing connected to packer, there is a great number of problems to be solved. Changes in temperatures and pressures that occure during various operations ussually result in changes in tubing lengths or tubing to packer forces, depending on tubing to packer connections. This paper summarises some earlier papers and explains partly elaborated details. It also gives a complete approach to solve problems in uniform strings r...

  20. Operating performance of CANDU pressure tubes

    International Nuclear Information System (INIS)

    Cheadle, B.A.; Price, E.G.

    1989-04-01

    The performance of Zircaloy-2 and Zr-2.5 Nb pressure tubes in CANDU reactors is reviewed. The accelerated hydriding of Zircaloy-2 in reducing water chemistries can lower the toughness of this material and it is essential that defect-initiating phenomena, such as hydride blister formation from pressure tube to calandria tube contact, be prevented. Zr-2.5 Nb pressure tubes are performing well with low rates of hydrogen pick-up and good retention of material properties

  1. 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.

  2. Influence of tube spinning on formability of friction stir welded aluminum alloy tubes for hydroforming application

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.S. [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Hu, Z.L., E-mail: zhilihuhit@163.com [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Hubei Key Laboratory of Advanced Technology of Automobile Parts, Wuhan University of Technology, Wuhan 430070 (China); State Key Laboratory of Materials Processing and Die and Mould Technology, Huazhong University of Science and Technology (China); Yuan, S.J. [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Hua, L. [Hubei Key Laboratory of Advanced Technology of Automobile Parts, Wuhan University of Technology, Wuhan 430070 (China)

    2014-06-01

    Due to economic and ecological reasons, the application of tailor-welded blanks of aluminum alloy has gained more and more attention in manufacturing lightweight structures for automotives and aircrafts. In the study, the research was aimed to highlight the influence of spinning on the formability of FSW tubes. The microstructural characteristics of the FSW tubes during spinning were studied by electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM). The formability of the FSW tubes with different spinning reduction was assessed by hydraulic bulge test. It is found that the spinning process shows a grain refinement of the tube. The grains of the FSW tube decrease with increasing thickness reduction, and the effect of grain refinement is more obvious for the BM compared to that of the weld. The difference of grain size and precipitates between the weld and BM leads to an asymmetric W-type microhardness distribution after spinning. The higher thickness reduction of the tube, the more uniform distribution of grains and precipitates it shows, and consequently results in more significant increase of strength. As compared with the result of tensile test, the tube after spinning shows better formability when the stress state changes from uniaxial to biaxial stress state.

  3. Numerical simulation of the double pits stress concentration in a curved casing inner surface

    Directory of Open Access Journals (Sweden)

    Wei Yan

    2016-12-01

    Full Text Available Sour or sweet oil fields development is common in recent years. Casing and tubing are usually subjected to pitting corrosion because of exposure to the strong corrosion species, such as CO2, H2S, and saline water. When the corrosion pits formed in the casing inner surface, localized stress concentration will occur and the casing strength will be degraded. Thus, it is essential to evaluate the degree of stress concentration factor accurately. This article performed a numerical simulation on double pits stress concentration factor in a curved inner surface using the finite element software ABAQUS. The results show that the stress concentration factor of double pits mainly depends on the ratio of two pits distance to the pit radius (L/R. It should not be only assessed by the absolute distance between the two pits. When the two pits are close and tangent, the maximum stress concentration factor will appear on the inner tangential edges. Stress concentration increased by double pits in a curved casing inner surface is more serious than that in a flat surface. A correction factor of 1.9 was recommended in the curved inner surface double pits stress concentration factor predict model.

  4. Microstructure, elastic deformation behavior and mechanical properties of biomedical β-type titanium alloy thin-tube used for stents.

    Science.gov (United States)

    Tian, Yuxing; Yu, Zhentao; Ong, Chun Yee Aaron; Kent, Damon; Wang, Gui

    2015-05-01

    Cold-deformability and mechanical compatibility of the biomedical β-type titanium alloy are the foremost considerations for their application in stents, because the lower ductility restricts the cold-forming of thin-tube and unsatisfactory mechanical performance causes a failed tissue repair. In this paper, β-type titanium alloy (Ti-25Nb-3Zr-3Mo-2Sn, wt%) thin-tube fabricated by routine cold rolling is reported for the first time, and its elastic behavior and mechanical properties are discussed for the various microstructures. The as cold-rolled tube exhibits nonlinear elastic behavior with large recoverable strain of 2.3%. After annealing and aging, a nonlinear elasticity, considered as the intermediate stage between "double yielding" and normal linear elasticity, is attributable to a moderate precipitation of α phase. Quantitive relationships are established between volume fraction of α phase (Vα) and elastic modulus, strength as well as maximal recoverable strain (εmax-R), where the εmax-R of above 2.0% corresponds to the Vα range of 3-10%. It is considered that the "mechanical" stabilization of the (α+β) microstructure is a possible elastic mechanism for explaining the nonlinear elastic behavior. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Tube vibration in industrial size test heat exchanger

    International Nuclear Information System (INIS)

    Halle, H.; Wambsganss, M.W.

    1980-03-01

    Tube vibration data from tests of a specially built and instrumented, industrial-type, shell-and-tube heat exchanger are reported. The heat exchanger is nominally 0.6 m (2 ft) in dia and 3.7 m (12 ft) long. Both full tube and no-tubes-in-window bundles were tested for inlet/outlet nozzles of different sizes and with the tubes supported by seven, equally-spaced, single-segmental baffles. Prior to water flow testing, natural frequencies and damping of representative tubes were measured in air and water. Flow testing was accomplished by increasing the flow rates in stepwise fashion and also by sweeping through a selected range of flow rates. The primary variables measured and reported are tube accelerations and/or displacements and pressure drop through the bundle. Tests of the full tube bundle configuration revealed tube rattling to occur at intermediate flow rates, and fluidelastic instability, with resultant tube impacting, to occur when the flow rate exceeded a threshold level; principally, the four-span tubes were involved in the regions immediately adjacent to the baffle cut. For the range of flow rates tested, fluidelastic instability was not achieved in the no-tubes-in-window bundle; in this configuration the tubes are supported by all seven baffles and are, therefore, stiffer

  6. Defensin-like ZmES4 mediates pollen tube burst in maize via opening of the potassium channel KZM1.

    Directory of Open Access Journals (Sweden)

    Suseno Amien

    2010-06-01

    Full Text Available In contrast to animals and lower plant species, sperm cells of flowering plants are non-motile and are transported to the female gametes via the pollen tube, i.e. the male gametophyte. Upon arrival at the female gametophyte two sperm cells are discharged into the receptive synergid cell to execute double fertilization. The first players involved in inter-gametophyte signaling to attract pollen tubes and to arrest their growth have been recently identified. In contrast the physiological mechanisms leading to pollen tube burst and thus sperm discharge remained elusive. Here, we describe the role of polymorphic defensin-like cysteine-rich proteins ZmES1-4 (Zea mays embryo sac from maize, leading to pollen tube growth arrest, burst, and explosive sperm release. ZmES1-4 genes are exclusively expressed in the cells of the female gametophyte. ZmES4-GFP fusion proteins accumulate in vesicles at the secretory zone of mature synergid cells and are released during the fertilization process. Using RNAi knock-down and synthetic ZmES4 proteins, we found that ZmES4 induces pollen tube burst in a species-preferential manner. Pollen tube plasma membrane depolarization, which occurs immediately after ZmES4 application, as well as channel blocker experiments point to a role of K(+-influx in the pollen tube rupture mechanism. Finally, we discovered the intrinsic rectifying K(+ channel KZM1 as a direct target of ZmES4. Following ZmES4 application, KZM1 opens at physiological membrane potentials and closes after wash-out. In conclusion, we suggest that vesicles containing ZmES4 are released from the synergid cells upon male-female gametophyte signaling. Subsequent interaction between ZmES4 and KZM1 results in channel opening and K(+ influx. We further suggest that K(+ influx leads to water uptake and culminates in osmotic tube burst. The species-preferential activity of polymorphic ZmES4 indicates that the mechanism described represents a pre-zygotic hybridization

  7. Defensin-Like ZmES4 Mediates Pollen Tube Burst in Maize via Opening of the Potassium Channel KZM1

    Science.gov (United States)

    Márton, Mihaela L.; Debener, Thomas; Geiger, Dietmar; Becker, Dirk; Dresselhaus, Thomas

    2010-01-01

    In contrast to animals and lower plant species, sperm cells of flowering plants are non-motile and are transported to the female gametes via the pollen tube, i.e. the male gametophyte. Upon arrival at the female gametophyte two sperm cells are discharged into the receptive synergid cell to execute double fertilization. The first players involved in inter-gametophyte signaling to attract pollen tubes and to arrest their growth have been recently identified. In contrast the physiological mechanisms leading to pollen tube burst and thus sperm discharge remained elusive. Here, we describe the role of polymorphic defensin-like cysteine-rich proteins ZmES1-4 (Zea mays embryo sac) from maize, leading to pollen tube growth arrest, burst, and explosive sperm release. ZmES1-4 genes are exclusively expressed in the cells of the female gametophyte. ZmES4-GFP fusion proteins accumulate in vesicles at the secretory zone of mature synergid cells and are released during the fertilization process. Using RNAi knock-down and synthetic ZmES4 proteins, we found that ZmES4 induces pollen tube burst in a species-preferential manner. Pollen tube plasma membrane depolarization, which occurs immediately after ZmES4 application, as well as channel blocker experiments point to a role of K+-influx in the pollen tube rupture mechanism. Finally, we discovered the intrinsic rectifying K+ channel KZM1 as a direct target of ZmES4. Following ZmES4 application, KZM1 opens at physiological membrane potentials and closes after wash-out. In conclusion, we suggest that vesicles containing ZmES4 are released from the synergid cells upon male-female gametophyte signaling. Subsequent interaction between ZmES4 and KZM1 results in channel opening and K+ influx. We further suggest that K+ influx leads to water uptake and culminates in osmotic tube burst. The species-preferential activity of polymorphic ZmES4 indicates that the mechanism described represents a pre-zygotic hybridization barrier and may be a

  8. Numerical simulation of pulse-tube refrigerators

    NARCIS (Netherlands)

    Lyulina, I.A.; Mattheij, R.M.M.; Tijsseling, A.S.; Waele, de A.T.A.M.

    2004-01-01

    A new numerical model has been introduced to study steady oscillatory heat and mass transfer in the tube section of a pulse-tube refrigerator. Conservation equations describing compressible gas flow in the tube are solved numerically, using high resolution schemes. The equation of conservation of

  9. Stop Smoking—Tube-In-Tube Helical System for Flameless Calcination of Minerals

    Directory of Open Access Journals (Sweden)

    Nils Haneklaus

    2017-11-01

    Full Text Available Mineral calcination worldwide accounts for some 5–10% of all anthropogenic carbon dioxide (CO2 emissions per year. Roughly half of the CO2 released results from burning fossil fuels for heat generation, while the other half is a product of the calcination reaction itself. Traditionally, the fuel combustion process and the calcination reaction take place together to enhance heat transfer. Systems have been proposed that separate fuel combustion and calcination to allow for the sequestration of pure CO2 from the calcination reaction for later storage/use and capture of the combustion gases. This work presents a new tube-in-tube helical system for the calcination of minerals that can use different heat transfer fluids (HTFs, employed or foreseen in concentrated solar power (CSP plants. The system is labeled ‘flameless’ since the HTF can be heated by other means than burning fossil fuels. If CSP or high-temperature nuclear reactors are used, direct CO2 emissions can be divided in half. The technical feasibility of the system has been accessed with a brief parametric study here. The results suggest that the introduced system is technically feasible given the parameters (total heat transfer coefficients, mass- and volume flows, outer tube friction factors, and –Nusselt numbers that are examined. Further experimental work will be required to better understand the performance of the tube-in-tube helical system for the flameless calcination of minerals.

  10. Tube Thoracostomy: Complications and Its Management

    Directory of Open Access Journals (Sweden)

    Emeka B. Kesieme

    2012-01-01

    Full Text Available Background. Tube thoracostomy is widely used throughout the medical, surgical, and critical care specialities. It is generally used to drain pleural collections either as elective or emergency. Complications resulting from tube thoracostomy can occasionally be life threatening. Aim. To present an update on the complications and management of complications of tube thoracostomy. Methods. A review of the publications obtained from Medline search, medical libraries, and Google on tube thoracostomy and its complications was done. Results. Tube thoracostomy is a common surgical procedure which can be performed by either the blunt dissection technique or the trocar technique. Complication rates are increased by the trocar technique. These complications have been broadly classified as either technical or infective. Technical causes include tube malposition, blocked drain, chest drain dislodgement, reexpansion pulmonary edema, subcutaneous emphysema, nerve injuries, cardiac and vascular injuries, oesophageal injuries, residual/postextubation pneumothorax, fistulae, tumor recurrence at insertion site, herniation through the site of thoracostomy, chylothorax, and cardiac dysrhythmias. Infective complications include empyema and surgical site infection. Conclusion. Tube thoracostomy, though commonly performed is not without risk. Blunt dissection technique has lower risk of complications and is hence recommended.

  11. Tube Thoracostomy: Complications and Its Management

    Science.gov (United States)

    Kesieme, Emeka B.; Dongo, Andrew; Ezemba, Ndubueze; Irekpita, Eshiobo; Jebbin, Nze; Kesieme, Chinenye

    2012-01-01

    Background. Tube thoracostomy is widely used throughout the medical, surgical, and critical care specialities. It is generally used to drain pleural collections either as elective or emergency. Complications resulting from tube thoracostomy can occasionally be life threatening. Aim. To present an update on the complications and management of complications of tube thoracostomy. Methods. A review of the publications obtained from Medline search, medical libraries, and Google on tube thoracostomy and its complications was done. Results. Tube thoracostomy is a common surgical procedure which can be performed by either the blunt dissection technique or the trocar technique. Complication rates are increased by the trocar technique. These complications have been broadly classified as either technical or infective. Technical causes include tube malposition, blocked drain, chest drain dislodgement, reexpansion pulmonary edema, subcutaneous emphysema, nerve injuries, cardiac and vascular injuries, oesophageal injuries, residual/postextubation pneumothorax, fistulae, tumor recurrence at insertion site, herniation through the site of thoracostomy, chylothorax, and cardiac dysrhythmias. Infective complications include empyema and surgical site infection. Conclusion. Tube thoracostomy, though commonly performed is not without risk. Blunt dissection technique has lower risk of complications and is hence recommended. PMID:22028963

  12. Bradycardia after Tube Thoracostomy for Spontaneous Pneumothorax

    Directory of Open Access Journals (Sweden)

    Yomi Fashola

    2018-01-01

    Full Text Available We present the case of an elderly patient who became bradycardic after chest tube insertion for spontaneous pneumothorax. Arrhythmia is a rare complication of tube thoracostomy. Unlike other reported cases of chest tube induced arrhythmias, the bradycardia in our patient responded to resuscitative measures without removal or repositioning of the tube. Our patient, who had COPD, presented with shortness of breath due to spontaneous pneumothorax. Moments after tube insertion, patient developed severe bradycardia that responded to Atropine. In patients requiring chest tube insertion, it is important to be prepared to provide cardiopulmonary resuscitative therapy in case the patient develops a life-threatening arrhythmia.

  13. A comparative Thermal Analysis of conventional parabolic receiver tube and Cavity model tube in a Solar Parabolic Concentrator

    Science.gov (United States)

    Arumugam, S.; Ramakrishna, P.; Sangavi, S.

    2018-02-01

    Improvements in heating technology with solar energy is gaining focus, especially solar parabolic collectors. Solar heating in conventional parabolic collectors is done with the help of radiation concentration on receiver tubes. Conventional receiver tubes are open to atmosphere and loose heat by ambient air currents. In order to reduce the convection losses and also to improve the aperture area, we designed a tube with cavity. This study is a comparative performance behaviour of conventional tube and cavity model tube. The performance formulae were derived for the cavity model based on conventional model. Reduction in overall heat loss coefficient was observed for cavity model, though collector heat removal factor and collector efficiency were nearly same for both models. Improvement in efficiency was also observed in the cavity model’s performance. The approach towards the design of a cavity model tube as the receiver tube in solar parabolic collectors gave improved results and proved as a good consideration.

  14. Elastic-plastic analysis of tube expansion in tubesheets

    International Nuclear Information System (INIS)

    Kasraie, B.; O'Donnell, W.J.; Porowski, J.S.; Selz, A.

    1983-01-01

    Conditions for expansion of tubes in tubesheets are often determined by the test. The tightness of the joint and pull out force are used as criteria for evaluation of the results. For closely spaced tubes, it is also necessary to control development of the plastic regions in the ligaments surrounding the tube being expanded. High local strains may occur and excessive distortion may result if the expansion of the tube is continued beyond the admissible limits. Elastic-plastic finite element analyses are performed herein in order to establish conditions for rolling of the tubes in tubesheets of low ligament efficiency. Such penetration patterns are often required in the design of tubular reactors for catalytic processes. The model considered includes individual tube expansion in tubesheets with triangular penetration patterns. The effect of prior expansion of the neighboring tubes is also evaluated. Gap elements are used to model the initial clearance of the tube in the hole. Development of the plastic zones and distortion of the ligaments is monitored during radial expansion of the tube diameter. The residual stresses between the tube and the hole surface and the history of gap closing after removal of the expansion tool are determined. The effect of axial extension of the tube on the tube thinning is determined. Tube thinning is often used as a measure of tube expansion in manufacturing processes. For the analyzed ligament efficiency, reliable joints are obtained for a thinning range within 2% to 3%

  15. Tube bundle vibrations in transversal flow

    International Nuclear Information System (INIS)

    Gibert, R.J.; Sagner, M.

    1978-01-01

    This study gives important information concerning characteristic parameters about lock-in and whirling instability phenomena, in the case of tube arrays. The work is mainly an experimental one though models are also developed: 1) an equilateral pitch bundle (p=1,5 D with D=tube diameter) is tested. Tube damping (epsilon) and first eigenfrequency (f), flow velocity are explored in a large domain. Vibratory level of the tubes are measured and critical points are ploted on the fluidelastic parameters diagram. Several bundles with various usual pitches and arrangements (in line or staggered) are tested. Critical velocities are measured and the whirling instability characteristic coefficient is tabulated. A complementary experiment is made on tube rows with various pitches. This gives valuable informations concerning the look-in domain in VR and A'R diagram. Furthermore this puts in evidence the important effect of a frequency difference between two adjacent tubes on the whirling critical velocity

  16. 21 CFR 888.4230 - Cement ventilation tube.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cement ventilation tube. 888.4230 Section 888.4230...) MEDICAL DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4230 Cement ventilation tube. (a) Identification. A cement ventilation tube is a tube-like device usually made of plastic intended to be inserted into...

  17. Analysis of forming limit in tube hydroforming

    International Nuclear Information System (INIS)

    Kim, Chan Il; Yang, Seung Hang; Kim, Young Suk

    2013-01-01

    The automotive industry has shown increasing interest in tube hydroforming. Despite many automobile structural parts being produced from cylindrical tubes, failures frequently occur during tube hydroforming under improper forming conditions. These problems include wrinkling, buckling, folding back, and bursting. We perform analytical studies to determine forming limits in tube hydroforming and demonstrate how these forming limits are influenced by the loading path. Theoretical results for the forming limits of wrinkling and bursting are compared with experimental results for an aluminum tube.

  18. Integrating YouTube into the nursing curriculum.

    Science.gov (United States)

    Sharoff, Leighsa

    2011-08-17

    Nurse educators need to be innovative, stimulating, and engaging as they teach future nursing professionals. The use of YouTube in nursing education classes provides an easy, innovative, and user-friendly way to engage today's nursing students. YouTube presentations can be easily adapted into nursing courses at any level, be it a fundamentals course for undergraduate students or a theoretical foundations course for graduate students. In this article I will provide information to help educators effectively integrate YouTube into their course offerings. I will start by reviewing the phenomenon of social networking. Next I will discuss challenges and strategies related to YouTube learning experiences, after which I will share some of the legal considerations in using YouTube. I will conclude by describing how to engage students via YouTube and current research related to YouTube.

  19. Tests of compressed geometry NEC acceleration tubes

    International Nuclear Information System (INIS)

    Raatz, J.E.; Rathmell, R.D.; Stelson, P.H.; Ziegler, N.F.

    1985-01-01

    Tests have been performed in the 3 MV Pelletron test machine at NEC on a compressed geometry tube which increases the insulating length of the tube by eliminating the heated electrode assemblies (approx.2.5 cm thick) at the end of each tube section. Some insert electrodes are changed to provide some trapping of secondary ions. The geometry tested provided an 18% increase in live ceramic in the tube. The compressed geometry tube allowed a terminal voltage of 3.55 MV on the 3 MV column at normal gradients of 30.3 kv/tube gap. The tube was also conditioned to more than 4 MV and remained stable in voltage with few sparks and with low x-ray levels for days at about 4 MV. This same performance could be achieved with or without arc discharge cleaning. 4 refs., 4 figs

  20. Positive pressure ventilation in a patient with a right upper lobar bronchocutaneous fistula: right upper bronchus occlusion using the cuff of a left-sided double lumen endobronchial tube.

    Science.gov (United States)

    Omori, Chieko; Toyama, Hiroaki; Takei, Yusuke; Ejima, Yutaka; Yamauchi, Masanori

    2017-08-01

    In patients with a bronchocutaneous fistula, positive pressure ventilation leads to air leakage and potential hypoxemia. A male patient with a right upper bronchocutaneous fistula was scheduled for esophageal reconstruction. His preoperative chest computed tomography image revealed aeration in the right middle and lower lobe, a large bulla in the left upper lobe, and pleural effusion and pneumonia in the left lower lobe. Therefore, left one-lung ventilation was considered to result in hypoxemia. Before anesthesia induction, the bronchocutaneous fistula was covered with gauze and film to prevent air leakage. After anesthesia induction, mask ventilation was performed with a peak positive pressure of 10 cmH 2 O. A left-sided double lumen endobronchial tube (DLT) was then inserted into the right main bronchus for occluding only the right superior bronchus, and two-lung ventilation was performed to minimize airway pressure and maintain oxygenation, which did not cause air leakage through the fistula. During anesthesia, no ventilation-related difficulty was faced. The method of inserting a left-sided DLT into the right main bronchus and occluding the right upper bronchus selectively by bronchial cuff is considered to be an option for mechanical ventilation in patients with a right upper bronchial fistula, as demonstrated in the present case.

  1. Tensile properties of quadruple melted Zr-2.5Nb pressure tubes evaluated from pressure tube offcuts

    International Nuclear Information System (INIS)

    Shah, Priti Kotak; Dubey, J.S.; Anantharaman, S.

    2013-12-01

    Rajasthan Atomic Power Station-2 (RAPS-2) is the first Pressurised Heavy Water Reactor (PHWR) in India having quadruple melted Zr-2.5Nb pressure tubes. Front-end and back-end off-cuts of sixteen pressure tubes were selected for studying the mechanical properties in axial and transverse directions of the tube. Tension tests were carried out at room temperature and at 300℃ using miniature tensile test specimens. The report presents the experimental details and discusses the base line tensile property data for the quadruple melted pressure tubes of RAPS-2. This data will be useful for the reactor life management. (author)

  2. Caring for Your Percutaneous Nephrostomy Tube

    Science.gov (United States)

    ... to the nephrostomy tube for 15 seconds. 5. Disconnect the drainage bag from the tube. 6. Put the used bag aside. 7. With a new alcohol pad, swab the open end of the nephrostomy tube for 15 seconds. 8. Connect a new bag. 9. Secure the drainage bag ...

  3. The Fuge Tube Diode Array Spectrophotometer

    Science.gov (United States)

    Arneson, B. T.; Long, S. R.; Stewart, K. K.; Lagowski, J. J.

    2008-01-01

    We present the details for adapting a diode array UV-vis spectrophotometer to incorporate the use of polypropylene microcentrifuge tubes--fuge tubes--as cuvettes. Optical data are presented validating that the polyethylene fuge tubes are equivalent to the standard square cross section polystyrene or glass cuvettes generally used in…

  4. 21 CFR 872.6570 - Impression tube.

    Science.gov (United States)

    2010-04-01

    ... DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6570 Impression tube. (a) Identification. An impression tube is a device consisting of a hollow copper tube intended to take an impression of a single tooth...) Classification. Class I (general controls). The device is exempt from the premarket notification procedures in...

  5. Double containment shell for nuclear power plants

    International Nuclear Information System (INIS)

    Sykora, D.

    1977-01-01

    A double containment shell is proposed for nuclear power plants, especially those equipped with pressurized water reactors. The shell offers increased environmental protection from primary circuit accidents. The inner shell is built of steel or concrete while the outer shell is always built of concrete. The space between the two shells is filled with water and is provided with several manholes and with stiffeners designed for compensation for load due to the water hydrostatic pressure. Water serves the airtight separation of the containment shell inside from the environment and the absorption of heat released in a primary circuit accident. In case the inner shell is made of concrete, it is provided with heat-removal tubes in-built in its walls ensuring rapid heat transfer from the inside of the containment to the water in the interwall space. (Z.M.)

  6. Double-shell target fabrication workshop-2016 report

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y. Morris [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Oertel, John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Farrell, Michael [General Atomics, San Diego, CA (United States); Baumann, Ted [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Huang, Haibo [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nikroo, Abbas [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-01-10

    On June 30, 2016, over 40 representatives from Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), General Atomics (GA), Laboratory for Laser Energetics (LLE), Schafer Corporation, and NNSA headquarter attended a double-shell (DS) target fabrication workshop at Livermore, California. Pushered-single-shell (PSS) and DS metalgas platforms potentially have a large impact on programmatic applications. The goal of this focused workshop is to bring together target fabrication scientists, physicists, and designers to brainstorm future PSS and DS target fabrication needs and strategies. This one-day workshop intends to give an overall view of historical information, recent approaches, and future research activities at each participating organization. Five topical areas have been discussed that are vital to the success of future DS target fabrications, including inner metal shells, foam spheres, outer ablators, fill tube assembly, and metrology.

  7. Preparation of metallic uranium tubes; Elaboration des tubes d'uranium metallique

    Energy Technology Data Exchange (ETDEWEB)

    Lerouge, G.; Decours, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    The production furnace is an induction heated vacuum furnace having a capacity at the moment of 250 kg. Previously the crucible was heated by the inductor, the mould being outside the inductor. The tubes thus produced contained cavities, the alloy structure was fine; this was cold-mould casting, At the moment the top of the moulds are pre-heated, this is the so called hot-mould casting. This method has the advantage of eliminating the cavities but leads to a less fine microstructure. The alloy used for the 18 x 40 mm and 23 x 43 mm tubes is U-Mo (1.1 per cent). Since the moulds are now heated at the top, the solidification of the metal is very slow in this zone leading to a pronounced {gamma} grain, whereas towards the base the faster cooling leads to a smaller {gamma} grain. The {gamma} structure depends essentially on the solidification rate and on the time spent in this zone. In order to obtain a fine and homogeneous grain along the whole length of the tube, a controlled cooling treatment is effected. It consists in heating the uranium tubes in the {gamma} place and then in cooling them at a rate of between 20 and 50 deg C/mm down to 400 deg C. The 77 x 95 mm and 54 x 70 mm annular elements are at the moment being produced for research purposes. Their preparation is similar to that of 18 x 40 mm and 23 x 43 mm elements. The 77 x 95 mm tubes are at the moment made from U-Cr alloy (0.1 per cent); because of their size, their preparation is carried out in 600 mm diameter furnaces. (authors) [French] Le four d'elaboration est un four sous vide chaufffe par induction, dont la capacite actuelle est de 250 kg. Anterieurement le creuset seul etait chauffe par l'inducteur, les moules etaient hors de l'inducteur. Les tubes obtenus presentaient des cavites, la structure de l'alliage etait fine, c'etait la coulee en moules froids. Actuellement on prechauffe le haut des moules, c'est la coulee dite en moules chauds. Cette facon de faire a l

  8. Researching YouTube

    OpenAIRE

    Arthurs, Jane; Drakopoulou, Sophia; Gandini, Alessandro

    2018-01-01

    ‘Researching YouTube’ introduces the special issue of Convergence which arose out of an international academic conference on YouTube that was held in London at Middlesex University in September 2016. The conference aimed to generate a robust overview of YouTube’s changing character and significance after its first ten years of development by creating a productive dialogue between speakers from different disciplines and cultures, and between YouTube-specific research and wider debates in media...

  9. Contribution to the heat transfer analysis of substitute refrigerants in evaporator tubes with smooth or enhanced tube surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kattan, N

    1997-12-31

    The substitution of CFC refrigerants in refrigeration systems, heat pumps and organic Rankine cycles for heat recovery, requests a good knowledge of heat transfer properties of substitute fluids. A new test facility has been built at the Laboratory for Industrial Energy Systems (LENI) to contribute to this international effort. It consists of two sets of concentric tubes allowing either annular or inside tube convective boiling with a counter current water flow heating to be studied. A new data base including heat transfer coefficients and pressure drop measurements for four new refrigerants (R123, R134A, R402A and R404A) and three older refrigerants (R11, R12 and R502) has been collected. Flow boiling measurements covered a broad range of mass velocities, vapor qualities and heat fluxes. Some of the tests included plain tubes and others enhanced surface tubes (microfilms from Wieland) in horizontal and vertical orientations. An improved Wilson plot technique, that covers both the transition and turbulent flow regimes of the water flowing in the annular channel for the inside tube boiling tests, is proposed to overcome the severe limitations of conventional Wilson plots, to improve accuracy and to facilitate data processing. Mean flow boiling heat transfer coefficients were measured for R12 and R134A evaporating inside a horizontal plain tube and for R11 and R123 evaporating inside a horizontal plain tube. Local flow boiling heat transfer coefficients were measured for : R134A, R123, R404A and R502 evaporating inside a horizontal plain tube, for R134A and R123 evaporating inside a horizontal microfin tube and for R134 evaporating inside a vertical microfin tube. In addition microfin heat transfer augmentation relative to plain tube test data was investigated. The measured heat transfer coefficients were compared to different existing inside tube flow boiling correlations. (author) figs., tabs., refs.

  10. Double photoionisation in Rb and Cs in the threshold region

    International Nuclear Information System (INIS)

    Holland, D.M.P.; Codling, K.

    1981-01-01

    The extreme ultraviolet radiation emitted by the Bonn 2.5-GeV electron synchrotron, monochromatised by a 1-m vertically-dispersing Seya. The radiation, of 2 Angstroem band-pass (0.15 eV at 30 eV), was incident on an atomic beam of Rb or Cs vapour produced by a resistively heated oven. To avoid excessive oxidation, the oven was loaded with the alkali metal still under petroleum spirit and the residual spirit removed on evacuation of the system. The drift tube of a time-of-flight (TOF) mass spectrometer was placed at right angles to both the photon and atomic beams. The singly and doubly charged ions were pulsed out of the interaction region and detected by a microchannel-plate assembly placed at the end of the drift tube. The results for Rb are neither so accurate nor extensive as for Cs because a peak at mass number 44 in the TOF spectrum (probably CO 2 ), due to emission from the oven region, obscured the small Rb 2+ peak. The results for both Rb and Cs are shown as the ratios of double-to-single photoionisation. (orig./AH)

  11. Measurements of electrically exploded tubes

    International Nuclear Information System (INIS)

    Shearer, J.W.; Hartman, C.W.; Munger, R.H.; Gullickson, R.L.; Trimble, D.O.; Cheng, D.Y.

    1975-01-01

    The dynamics of electrically exploded tubes were investigated, principally by means of current measurements and flash x-ray pictures. The pinch effect was observed on the tube motion. Pileup of the imploding tube metal was seen on axis. An approximate analytical model can be roughly fitted to the data, but a more complete fit can be obtained with detailed numerical codes. Application of the results to the planning of future gas-embedded Z-pinch experiments is discussed. (U.S.)

  12. Photomultiplier tubes for Low Level Cerenkov Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Strindehag, O

    1965-03-15

    Tube backgrounds of several 2-inch photomultiplier types having S11, 'S' , S13 and S20 cathodes are compared by measuring signal and background pulse height distributions at pulse heights corresponding to a few photo-electrons. The reference signal is generated by means of a {beta}-source and a plexiglass radiator. It is found that comparatively good results are obtained with selected tubes of the EMI types 6097B and 9514B having equivalent dark current dc values down to 10{sup -12} input lumens. Special interest is devoted to the correlation between the measured tube backgrounds and the dark current dc values of the tubes, as a good correlation between these parameters simplifies the selection of photomultiplier tubes. The equivalent dark currents of the tested tubes extend over the range 10{sup -12} to 10{sup -9} input lumens. Although the investigation deals with photomultiplier tubes intended for use in low level Cerenkov detectors it is believed that the results could be valuable in other fields where photomultiplier tubes are utilized for the detection of weak light pulses.

  13. Confined Tube Crimp Using Portable Hand Tools

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, Joseph James [Los Alamos National Laboratory; Pereyra, R. A. [LANL Retired; Archuleta, Jeffrey Christopher [Los Alamos National Laboratory; Martinez, Isaac P. [Los Alamos National Laboratory; Nelson, A. M. [MST-16 Summer Student (2007); Allen, Ronald Scott [Los Alamos National Laboratory; Page, R. L. [LANL Retired; Freer, Jerry Eugene [Los Alamos National Laboratory; Dozhier, Nathan Gus [Los Alamos National Laboratory

    2016-04-04

    The Lawrence Radiation Laboratory developed handheld tools that crimp a 1/16 inch OD tube, forming a leak tight seal1 (see Figure 1). The leak tight seal forms by confining the 1/16 inch OD tubing inside a die while applying crimp pressure. Under confined pressure, the tube walls weld at the crimp. The purpose of this study was to determine conditions for fabricating a leak tight tube weld. The equipment was used on a trial-and-error basis, changing the conditions after each attempt until successful welds were fabricated. To better confine the tube, the die faces were polished. Polishing removed a few thousandths of an inch from the die face, resulting in a tighter grip on the tubing wall. Using detergent in an ultrasonic bath, the tubing was cleaned. Also, the time under crimp pressure was increased to 30 seconds. With these modifications, acceptable cold welds were fabricated. After setting the conditions for an acceptable cold weld, the tube was TIG welded across the crimped face.

  14. Photomultiplier tubes for Low Level Cerenkov Detectors

    International Nuclear Information System (INIS)

    Strindehag, O.

    1965-03-01

    Tube backgrounds of several 2-inch photomultiplier types having S11, 'S' , S13 and S20 cathodes are compared by measuring signal and background pulse height distributions at pulse heights corresponding to a few photo-electrons. The reference signal is generated by means of a β-source and a plexiglass radiator. It is found that comparatively good results are obtained with selected tubes of the EMI types 6097B and 9514B having equivalent dark current dc values down to 10 -12 input lumens. Special interest is devoted to the correlation between the measured tube backgrounds and the dark current dc values of the tubes, as a good correlation between these parameters simplifies the selection of photomultiplier tubes. The equivalent dark currents of the tested tubes extend over the range 10 -12 to 10 -9 input lumens. Although the investigation deals with photomultiplier tubes intended for use in low level Cerenkov detectors it is believed that the results could be valuable in other fields where photomultiplier tubes are utilized for the detection of weak light pulses

  15. Ion Implantation Hampers Pollen Tube Growth and Disrupts Actin Cytoskeleton Organization in Pollen Tubes of Pinus thunbergii

    International Nuclear Information System (INIS)

    Li Guoping; Yang Lusheng; Huang Qunce; Qin Guangyong

    2008-01-01

    Pollen grains of Pinus thunbergii Parl. (Japanese black pine) were implanted with 30 keV nitrogen ion beams and the effects of nitrogen ion implantation on pollen tube growth in vitro and the organization of actin cytoskeleton in the pollen tube cell were investigated using a confocal laser scanning microscope after fluorescence labeling. Treatment with ion implantation significantly blocked pollen tube growth. Confocal microscopy showed that ion implantation disrupted actin filament cytoskeleton organization in the pollen tube. It was found that there was a distinct correlation between the inhibition of pollen tube growth and the disruption of actin cytoskeleton organization, indicating that an intact actin cytoskeleton is essential for continuous pollen tube elongation in Pinus thunbergii. Although the detailed mechanism for the ion-implantation-induced bioeffect still remains to be elucidated, the present study assumes that the cytoskeleton system in pollen grains may provide a key target in response to ion beam implantation and is involved in mediating certain subsequent cytological changes.

  16. N Reactor pressure tube 2566 postirradiation examination

    International Nuclear Information System (INIS)

    Scott, K.V.

    1978-01-01

    Pressure tube 2566 was removed from N Reactor in July, 1977 to initiate the postirradiation examination program required by the Technical Specifications. Destructive examination of the pressure tube, after a maximum accumulated fluence of 4.6 x 10 21 n/cm 2 (E > 1 MeV), was conducted at the Hanford Engineering Development Laboratory to determine the effects of reactor service on the mechanical properties and hydrogen absorption and corrosion characteristics of the pressure tube. Tube 2566 is the sixth tube removed for destructive examination since the initial reactor startup. Evaluation of test results reveal that no significant detrimental changes have occurred in the parameters studied, since the last tube was removed in 1974

  17. Experimental study of micro-shock tube flow

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jin Ouk; Kim, Gyu Wan; Rasel, Md. Alim Iftakhar [Dept. of Mechanical Engineering, Andong National University, Andong (Korea, Republic of); Kim, Heuy Dong [Fire Research Center, Korea Institute of Civil Engineering and Building Technology, Hwasung (Korea, Republic of)

    2015-03-15

    The flow characteristics in micro shock tube are investigated experimentally. Studies were carried out using a stainless steel micro shock tube. Shock and expansion wave was measured using 8 pressure sensors. The initial pressure ratio was varied from 4.3 to 30.5, and the diameter of tube was also changed from 3 mm to 6 mm. Diaphragm conditions were varied using two types of diaphragms. The results obtained show that the shock strength in the tube becomes stronger for an increase in the initial pressure ratio and diameter of tube. For the thinner diaphragm, the highest shock strength was found among varied diaphragm condition. Shock attenuation was highly influenced by the diameter of tube.

  18. Non-destructive controls in the steel tube industry

    International Nuclear Information System (INIS)

    Mondot, J.

    1978-01-01

    The main non-destructive control methods in the tube industry are reviewed: eddy currents, particularly well adapted to small tubes; magnetoscopic testing for weldless tubes; ultrasonic waves widely used for thick weldless tubes and weldings; radiography, to examine tube ends and the known questionable zones; measure of diameters by laser [fr

  19. Self-shielding flex-circuit drift tube, drift tube assembly and method of making

    Science.gov (United States)

    Jones, David Alexander

    2016-04-26

    The present disclosure is directed to an ion mobility drift tube fabricated using flex-circuit technology in which every other drift electrode is on a different layer of the flex-circuit and each drift electrode partially overlaps the adjacent electrodes on the other layer. This results in a self-shielding effect where the drift electrodes themselves shield the interior of the drift tube from unwanted electro-magnetic noise. In addition, this drift tube can be manufactured with an integral flex-heater for temperature control. This design will significantly improve the noise immunity, size, weight, and power requirements of hand-held ion mobility systems such as those used for explosive detection.

  20. 21 CFR 868.5975 - Ventilator tubing.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ventilator tubing. 868.5975 Section 868.5975 Food... DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5975 Ventilator tubing. (a) Identification. Ventilator tubing is a device intended for use as a conduit for gases between a ventilator and a patient...

  1. Disc-Donut-Tube wear test report, Phase I

    International Nuclear Information System (INIS)

    Kowal, K.; Knaus, S.E.

    1976-06-01

    The report describes a test program which simulated the wear-inducing conditions in the AI Prototype CRBR Steam Generator. This was accomplished by simulating the wear inducing loading and motion of a steam tube against ''disc-donut'' tube spacer plates. It was found that 2- 1 / 4 Cr-1 Mo tubes, wearing against 2- 1 / 4 Cr-l Mo tube spacer plates, seized and galled as deep as .017 inches. Inconel 718 tube spacer plates uniformly wore the tubes as deep as .012 in. Aluminum bronze inserts wore as deep as .003 inches into the tube

  2. Source Terms for HFIR Beam Tube Shielding Analyses, and a Complete Shielding Analysis of the HB-3 Tube

    International Nuclear Information System (INIS)

    Bucholz, J.A.

    2000-01-01

    The High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory is in the midst of a massive upgrade program to enhance experimental facilities. The reactor presently has four horizontal experimental beam tubes, all of which will be replaced or redesigned. The HB-2 beam tube will be enlarged to support more guide tubes, while the HB-4 beam tube will soon include a cold neutron source

  3. Source Terms for HFIR Beam Tube Shielding Analyses, and a Complete Shielding Analysis of the HB-3 Tube

    Energy Technology Data Exchange (ETDEWEB)

    Bucholz, J.A.

    2000-07-01

    The High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory is in the midst of a massive upgrade program to enhance experimental facilities. The reactor presently has four horizontal experimental beam tubes, all of which will be replaced or redesigned. The HB-2 beam tube will be enlarged to support more guide tubes, while the HB-4 beam tube will soon include a cold neutron source.

  4. Evaluation of steam generator tube integrity during earthquakes

    Energy Technology Data Exchange (ETDEWEB)

    Kusakabe, Takaya; Kodama, Toshio [Mitsubishi Heavy Industries Ltd., Kobe (Japan). Kobe Shipyard and Machinery Works; Takamatsu, Hiroshi; Matsunaga, Tomoya

    1999-07-01

    This report shows an experimental study on the strength of PWR steam generator (SG) tubes with various defects under cyclic loads which simulate earthquakes. The tests were done using same SG tubing as actual plants with axial and circumferential defects with various length and depth. In the tests, straight tubes were loaded with cyclic bending moments to simulate earthquake waves and number of load cycles at which tube leak started or tube burst was counted. The test results showed that even tubes with very long crack made by EDM more than 80% depth could stand the maximum earthquake, and tubes with corrosion crack were far stronger than those. Thus the integrity of SG tubes with minute potential defects was demonstrated. (author)

  5. Research on temperature control and influence of the vacuum tubes with inserted tubes solar heater

    Science.gov (United States)

    Xiao, L. X.; He, Y. T.; Hua, J. Q.

    2017-11-01

    A novel snake-shape vacuum tube with inserted tubes solar collector is designed in this paper, the heat transfer characteristics of the collector are analyzed according to its structural characteristics, and the influence of different working temperature on thermal characteristics of the collector is studied. The solar water heater prototype consisting of 14 vacuum tubes with inserted tubes is prepared, and the hot water storage control subsystem is designed by hysteresis comparison algorithm. The heat characteristic of the prototype was experimentally studied under hot water output temperature of 40-45°C, 50-55°C and 60-65°C. The daily thermal efficiency was 64%, 50% and 46%, respectively. The experimental results are basically consistent with the theoretical analysis.

  6. Inspection tool for butt-welded tubing

    Science.gov (United States)

    Horman, D. P.

    1977-01-01

    Inspection tool for tubing consists of metal casing housing elastic collar. Collar is clamped around weld site under test. Leakage through weld is contained within chamber and is bled to detector via tubing attached to fitting. Tool, originally designed to detect fluid leakage in tubing, can be used to detect gas leaks.

  7. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... YouTube Videos: Amblyopia Embedded video for NEI YouTube Videos: Amblyopia ... *PDF files require the free Adobe® Reader® software for viewing. This website is maintained by the ...

  8. Cladding tube manufacturing technology

    International Nuclear Information System (INIS)

    Hahn, R.; Jeong, Y. H.; Baek, B. J.; Kim, K. H.; Kim, S. J.; Choi, B. K.; Kim, J. M.

    1999-04-01

    This report gives an overview of the manufacturing routine of PWR cladding tubes. The routine essentially consists of a series of deformation and annealing processes which are necessary to transform the ingot geometry to tube dimensions. By changing shape, microstructure and structure-related properties are altered simultaneously. First, a short overview of the basics of that part of deformation geometry is given which is related to tube reducing operations. Then those processes of the manufacturing routine which change the microstructure are depicted, and the influence of certain process parameters on microstructure and material properties are shown. The influence of the resulting microstructure on material properties is not discussed in detail, since it is described in my previous report A lloy Development for High Burnup Cladding . Because of their paramount importance still up to now, and because manufacturing data and their influence on properties for other alloys are not so well established or published, the descriptions are mostly related to Zry4 tube manufacturing, and are only in short for other alloys. (author). 9 refs., 46 figs

  9. Cladding tube manufacturing technology

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, R. [Kraftwerk Union AG, Mulheim (Germany); Jeong, Y.H.; Baek, B.J.; Kim, K.H.; Kim, S.J.; Choi, B.K.; Kim, J.M. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1999-04-01

    This report gives an overview of the manufacturing routine of PWR cladding tubes. The routine essentially consists of a series of deformation and annealing processes which are necessary to transform the ingot geometry to tube dimensions. By changing shape, microstructure and structure-related properties are altered simultaneously. First, a short overview of the basics of that part of deformation geometry is given which is related to tube reducing operations. Then those processes of the manufacturing routine which change the microstructure are depicted, and the influence of certain process parameters on microstructure and material properties are shown. The influence of the resulting microstructure on material properties is not discussed in detail, since it is described in my previous report 'Alloy Development for High Burnup Cladding.' Because of their paramount importance still up to now, and because manufacturing data and their influence on properties for other alloys are not so well established or published, the descriptions are mostly related to Zry4 tube manufacturing, and are only in short for other alloys. (author). 9 refs., 46 figs.

  10. A calculation and measurement of the flow field in a steam condenser external to the tube nest

    International Nuclear Information System (INIS)

    Stastny, M.; Feistauer, M.

    1989-01-01

    The suggested physical and mathematical model is used to solve the flow of steam normal to the cooling tubes of condenser cross-sections in the region external to the nests. Numerical calculations are carried out by means of a multipurpose system of programmes for the finite element method and a programme for the boundary layer calculation. The results of the calculations are compared with measurements on the condenser of a 500MW steam turbine. The calculations of the flow field in a double pass condenser for the 1000MW saturated steam turbine are described. (author)

  11. Clinical tube weaning supported by hunger provocation in fully-tube-fed children.

    Science.gov (United States)

    Hartdorff, Caroline M; Kneepkens, C M Frank; Stok-Akerboom, Anita M; van Dijk-Lokkart, Elisabeth M; Engels, Michelle A H; Kindermann, Angelika

    2015-04-01

    Children with congenital malformations, mental retardation, and complex early medical history frequently have feeding problems. Although tube feeding is effective in providing the necessary energy and nutrients, it decreases the child's motivation to eat and may lead to oral aversion. In this study, we sought to confirm our previous results, showing that a multidisciplinary clinical hunger provocation program may lead to quick resumption of oral feeding. In a crossover study, 22 children of 9 to 24 months of age who were fully dependent on tube feeding were randomly assigned to one of two groups: group A, intervention group (2-week multidisciplinary clinical hunger provocation program); and group B, control group (4-week outpatient treatment by the same multidisciplinary team). Patients failing one treatment were reassigned to the other treatment group. Primary outcome measures were at least 75% orally fed at the conclusion of the intervention and fully orally fed and gaining weight 6 months after the intervention. In group A, 9/11 patients were successfully weaned from tube feeding (2 failures: 1 developed ulcerative colitis, 1 drop-out). In group B, only 1 patient was weaned successfully; 10/11 were reassigned to the clinical hunger provocation program, all being weaned successfully. Six months after the intervention, 1 patient had to resume tube feeding. In total, in the control group, 1/11 (9%) was weaned successfully as compared with 18/21 (86%) in the hunger provocation group (P hunger provocation is an effective short-term intervention for weaning young children from tube feeding.

  12. A continuous acceleration tube of ions under 200 KV; Un tube d'acceleration continue d'ions sous 200 KV

    Energy Technology Data Exchange (ETDEWEB)

    Mongodin, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1954-07-01

    The realization of an Van de Graaff accelerator required, for the preliminary studies, the construction of a small proton accelerator, functioning at 200 kV in order to resolve some parasitic effects inherent to the accelerators tubes. The aim of this report is to describe the different organs of the accelerator tube, to explain the operating system and to encode their characteristics. The report first presents the ion source and the beam buncher permitting to inject in the accelerator tube particles of about 9 kV and very batched in a thin beam of circular section. Then the study explain the tube characteristics considered like optic system. A method to obtain precise calculation of particle trajectories is exposed. Aberrations of the system were discussed and balance of the currents on all electrodes inside the tube for different regimes of working were provided. The influence of the residual pressure in the tube were explained. The report finally ends on a part of the fundamental problem of the straining occurring inside the tubes accelerators under high tension. (M.B.) [French] La realisation d n accelerateur du type Van de Graaff a necessite, entre autres etudes preliminaires, la construction d'un petit accelerateur de protons, fonctionnant sous 200 kV afin d'eclaircir certains effets parasites propres aux tubes accelerateurs. L'objet de ce rapport est de decrire les differents organes du tube accelerateur, d'en expliquer le fonctionnement et de chiffrer leurs caracteristiques. Le memoire presente d'abord la source d'ions et le canon permettant d'injecter dans le tube accelerateur des particules de 9 kV environ et bien groupees dans un faisceau fin de section circulaire. Puis il passe a l'etude du tube considere comme systeme optique. Une methode utilisee pour le calcul precis des trajectoires des particules y est exposee. Il aborde le probleme des aberrations de ce systeme et fournit par la suite le bilan des courants sur toutes les electrodes a l

  13. Characterization of 900 four-anode photomultiplier tubes for use in 2013 hadronic forward calorimeter upgrade.

    CERN Document Server

    AUTHOR|(CDS)2081071

    The first 900 four-anode Photomultiplier Tubes (PMTs) have been evaluated for use in the 2013 Hadronic Forward (HF) calorimeter upgrade. HF is a part of the Compact Muon Solenoid (CMS), which is one of the two large general-purpose particle detectors of the Large Hadron Collider (LHC) at CERN in Geneva, Switzerland. HF requires 1728 PMTs. These small tubes are the sensitive light detectors that provide the output signals of HF. Before installing PMTs in HF, their quality control demands need to be satisfied. These tests, done at the University of Iowa, are designed in three categories to test seventeen different parameters for each PMT. The three most basic and most important groups of parameters are: dark current, gain (anode and cathode), and timing. There are secondary tests which are performed on a smaller percentage of the PMTs such as surface uniformity, double pulse and single photo-electron resolution. The PMTs that meet the specifications of HF will be sent to CERN where they are expected to be in us...

  14. 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)

  15. Tube temperature rise limits: Boiling considerations

    Energy Technology Data Exchange (ETDEWEB)

    Vanderwater, R.G.

    1952-03-26

    A revision of tube power limits based on boiling considerations was presented earlier. The limits were given on a basis of tube power versus header pressure. However, for convenience of operation, the limits have been converted from tube power to permissible water temperature rise. The permissible {triangle}t`s water are given in this document.

  16. Fluoroscopically-guided transnasal insertion of ileus tube intestinal decompression in patients with inoperable malignant bowel obstruction

    International Nuclear Information System (INIS)

    Fang Shiming; Li Haili; Lin Qing; Mao Aiwu; Wu Shaoqiu; Jiang Haosheng; Cao Yan; Wang Zhenlei

    2011-01-01

    Objective: To assess the technical feasibility and effectiveness of fluoroscopically-guided transnasal insertion of ileus tube for intestinal decompression in the treatment of inoperable malignant bowel obstruction. Methods: A total of 211 patients with inoperable malignant bowel obstruction were enrolled in this study. The median KPS scale was 40 (ranged from 20 to 60). Under fluoroscopic guidance, transnasal insertion of ileus tube by using conventional technique or guidewire-catheter exchange technique was performed in all patients. The technical success rate, the clinical effective rate, the curative rate and adverse reactions as well as complications were documented. The correlation among the obstructive sites, obstruction causes and therapeutic effectiveness was analyzed. The ileus tube used in this study was a four-cavity and double-balloon catheter with a diameter of 16 F/18 f, which is produced by Cliny Company. Results: Transnasal drainage tube was successfully inserted into the proximal jejunum in all 211 patients with malignant bowel obstruction, and the total technical success rate was 100%. The initial technical success rate of the traditional technique and the catheter-guidewire exchange method was 85.5% (65/76) and 100% (135/135) respectively, the difference between the two was significant (P<0.05). After 24 hours, the clinical remission rate in the patients with high-level intestinal obstruction, lower-level intestinal obstruction and colorectal obstruction was 95.8% (46/48), 92.9% (117/126) and 83.8% (31/37), respectively. A follow-up of 4-245 days (mean 138 days) was conducted, and the total clinical cure rate was 27.5% (58/211). The clinical cure rate in small intestine obstruction and colorectal obstruction caused by primary tumor or recurrence was 12.7% (20/157) and 59.5% (22/37), respectively (P<0.05). The adverse reactions and complications included uncomfortable pharynx feeling or pain (99.1%, 199/221), the tube obstruction (23.2%, 49

  17. 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.

  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. Bronchial Blocker Versus Left Double-Lumen Endotracheal Tube for One-Lung Ventilation in Right Video-Assisted Thoracoscopic Surgery.

    Science.gov (United States)

    Lu, Yao; Dai, Wei; Zong, Zhijun; Xiao, Yimin; Wu, Di; Liu, Xuesheng; Chun Wong, Gordon Tin

    2018-02-01

    The aim of this study was to compare the quality of lung deflation of a left-sided double-lumen endotracheal tube (DLT) with a bronchial blocker (BB) for one-lung ventilation in video-assisted thoracic surgery (VATS). A prospective, randomized, clinical study. A university-affiliated teaching hospital. Forty-five adult patients undergoing esophageal tumor surgery using VATS with right lung deflation. Patients were assigned by a computer-generated randomization sequence to either the left-sided DLT or BB group. The correct positioning of the airway device was confirmed using fiberoptic bronchoscopy. The variables assessed included: (1) time required to correctly place the devices and to achieve lung collapse; (2) the number of times the device malpositioned; (3) the quality of lung deflation as rated by the surgeon; (4) blood pressure and heart rate at baseline (T 1 ), immediately before (T 2 ) and after (T 3 ) and 1 minute (T 4 ) after intubation; (5) the number of patients with hypoxemia (SpO 2 one-lung ventilation (OLV) period; and (6) postoperative hoarseness of voice, sore throat, or pulmonary infection. Of the 45 patients approached for the study, 21 patients in the DLT group and 19 patients in the BB group were analyzed. The time required to place the device in the correct position was similar between the 2 groups. The time to achieve right lung collapse in the BB group was significantly longer (mean difference: 3.232, 95% confidence interval [CI]: 1.993-4.471; p = 0.003). The quality of lung collapse, OLV duration, number of patients with device malposition, and hypoxemia in both groups were similar. There were more patients suffering hoarseness (odds ratio [OR]: 4.85, 95% CI: 1.08-21.76; p = 0.034) or sore throat (OR: 4.29, 95% CI: 1.14-16.18; p = 0.030) in the DLT group, while no patients developed postoperative lung infection in either group. Compared to T 1 , systolic blood pressure (sBP), diastolic BP (dBP), and heart rate (HR) at T 2 in both groups

  20. Measuring of tube expansion

    International Nuclear Information System (INIS)

    Vogeleer, J. P.

    1985-01-01

    The expansion of the primary tubes or sleeves of the steam generator of a nuclear reactor plant are measured while the tubes or sleeves are being expanded. A primary tube or sleeve is expanded by high pressure of water which flows through a channel in an expander body. The water is supplied through an elongated conductor and is introduced through a connector on the shank connected to the conductor at its outer end. A wire extends through the mandrel and through the conductor to the end of the connector. At its inner end the wire is connected to a tapered pin which is subject to counteracting forces produced by the pressure of the water. The force on the side where the wire is connected to the conductor is smaller than on the opposite side. The tapered pin is moved in the direction of the higher force and extrudes the wire outwardly of the conductor. The tapered surface of the tapered pin engages transverse captive plungers which are maintained in engagement with the expanding tube or sleeve as they are moved outwardly by the tapered pin. The wire and the connector extend out of the generator and, at its outer end, the wire is connected to an indicator which measures the extent to which the wire is moved by the tapered pin, thus measuring the expansion of the tube or sleeve as it progresses

  1. The local clinical validation of a new lithium heparin tube with a barrier: BD Vacutainer® Barricor LH Plasma tube

    Science.gov (United States)

    Arslan, Fatma Demet; Karakoyun, Inanc; Basok, Banu Isbilen; Aksit, Merve Zeytinli; Baysoy, Anil; Ozturk, Yasemin Kilic; Guclu, Yusuf Adnan; Duman, Can

    2017-01-01

    Introduction Although serum-providing blood tubes with a barrier are still widely used due to their significant advantages, the use of blood tubes with a barrier to provide plasma is becoming widespread. We compared 22 analytes in a BD Vacutainer® Barricor LH Plasma tube for local clinical validation of this new lithium heparin tube with a barrier. Materials and methods Samples from 44 volunteers were collected in different tubes (Becton Dickinson and Company): Z tube without additive (reference), clot-activator tube with gel (SST), lithium heparin tube without gel (LiH), and lithium heparin tube with barrier (Barricor). Analyte concentrations in different tubes were compared with the reference tube. All tubes were also evaluated according to additional testing (different centrifugation durations, blood-sampling techniques and individual differences). Results Aspartate aminotransferase (AST), glucose (Glc), potassium (K), lactate dehydrogenase (LD), sodium (Na), and total protein (TP) had a significant bias in Barricor (9.19%, - 3.24%, - 4.88%, 21.60%, - 0.40%, 5.03%, respectively) relative to the reference tube. There was no statistical difference between different centrifugation durations and individual differences for AST, K and LD in LiH and/or Barricor (P > 0.05). There was a significant bias for LD between LiH and Barricor in terms of blood-sampling techniques (21.2% and 12.4%, respectively). Conclusions Recently, the use of plasma has become prominent due to some of its advantages. In this study, plasma AST, K, LD, Glc and TP levels in Barricor were clinically different in comparison to serum. The results of additional tests showed that higher levels of LD in Barricor did not result from haemolysis, and they might be related to other factors including number of platelets, cellular fragility, or functional environment. PMID:28900369

  2. The local clinical validation of a new lithium heparin tube with a barrier: BD Vacutainer® Barricor LH Plasma tube.

    Science.gov (United States)

    Arslan, Fatma Demet; Karakoyun, Inanc; Basok, Banu Isbilen; Aksit, Merve Zeytinli; Baysoy, Anil; Ozturk, Yasemin Kilic; Guclu, Yusuf Adnan; Duman, Can

    2017-10-15

    Although serum-providing blood tubes with a barrier are still widely used due to their significant advantages, the use of blood tubes with a barrier to provide plasma is becoming widespread. We compared 22 analytes in a BD Vacutainer® Barricor LH Plasma tube for local clinical validation of this new lithium heparin tube with a barrier. Samples from 44 volunteers were collected in different tubes (Becton Dickinson and Company): Z tube without additive (reference), clot-activator tube with gel (SST), lithium heparin tube without gel (LiH), and lithium heparin tube with barrier (Barricor). Analyte concentrations in different tubes were compared with the reference tube. All tubes were also evaluated according to additional testing (different centrifugation durations, blood-sampling techniques and individual differences). Aspartate aminotransferase (AST), glucose (Glc), potassium (K), lactate dehydrogenase (LD), sodium (Na), and total protein (TP) had a significant bias in Barricor (9.19%, - 3.24%, - 4.88%, 21.60%, - 0.40%, 5.03%, respectively) relative to the reference tube. There was no statistical difference between different centrifugation durations and individual differences for AST, K and LD in LiH and/or Barricor (P > 0.05). There was a significant bias for LD between LiH and Barricor in terms of blood-sampling techniques (21.2% and 12.4%, respectively). Recently, the use of plasma has become prominent due to some of its advantages. In this study, plasma AST, K, LD, Glc and TP levels in Barricor were clinically different in comparison to serum. The results of additional tests showed that higher levels of LD in Barricor did not result from haemolysis, and they might be related to other factors including number of platelets, cellular fragility, or functional environment.

  3. Helical CT for lung-cancer screening. 3. Fundamental study for ultra-low-dose CT by application of small tube current and filter

    International Nuclear Information System (INIS)

    Itoh, Shigeki; Koyama, Shuji; Tusaka, Masatoshi; Maekoshi, Hisashi; Satake, Hiroko; Ishigaki, Takeo.

    1996-01-01

    In order to develop ultra-low-dose helical CT for lung cancer screening, the effect of reduction of the tube current to 20 mA and application of a 10 mm thick aluminium filter upon radiation dose and image quality was evaluated with a phantom. Exposure dose at the center of a gantry and absorbed dose at the center of an acrylic phantom at 20 mA with the filter were 15% and 29% of the dose at 50 mA without the filter, respectively. For reduction of absorbed dose, reduction of the tube current was more useful than application of the filter. Image noise at 20 mA with the filter was double that at 50 mA without the filter. Neither reduction of the tube current nor application of the filter changed full width at half maximum on section sensitivity of the Z-axis. Although reduction of the tube current did not affect the difference in CT values between an acrylic sphere and styroform, application of the filter caused a reduction of 4.5% in the difference in CT values. Neither reduction of the tube current nor application of the filter affected the contrast resolution of the high-contrast phantom; however, that of the low-contrast phantom deteriorated. Although improvement of the filter and evaluation of clinical images are necessary, reduction of the tube current to 20 mA and application of the aluminium filter appear to be a promising method for ultra-low-dose helical CT of the lung. (author)

  4. Investigation of the influence of image reconstruction filter and scan parameters on operation of automatic tube current modulation systems for different CT scanners

    International Nuclear Information System (INIS)

    Sookpeng, Supawitoo; Martin, Colin J.; Gentle, David J.

    2015-01-01

    Variation in the user selected CT scanning parameters under automatic tube current modulation (ATCM) between hospitals has a substantial influence on the radiation doses and image quality for patients. The aim of this study was to investigate the effect of changing image reconstruction filter and scan parameter settings on tube current, dose and image quality for various CT scanners operating under ATCM. The scan parameters varied were pitch factor, rotation time, collimator configuration, kVp, image thickness and image filter convolution (FC) used for reconstruction. The Toshiba scanner varies the tube current to achieve a set target noise. Changes in the FC setting and image thickness for the first reconstruction were the major factors affecting patient dose. A two-step change in FC from smoother to sharper filters doubles the dose, but is counterbalanced by an improvement in spatial resolution. In contrast, Philips and Siemens scanners maintained tube current values similar to those for a reference image and patient, and the tube current only varied slightly for changes in individual CT scan parameters. The selection of a sharp filter increased the image noise, while use of iDose iterative reconstruction reduced the noise. Since the principles used by CT manufacturers for ATCM vary, it is important that parameters which affect patient dose and image quality for each scanner are made clear to operator to aid in optimisation. (authors)

  5. Failure analysis of retired steam generator tubings

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hong Pyo; Kim, J. S.; Hwang, S. S. and others

    2005-04-15

    Degradation of steam generator leads to forced outage and extension of outage, which causes increase in repair cost, cost of purchasing replacement power and radiation exposure of workers. Steam generator tube rupture incident occurred in Uljin 4 in 2002, which made public sensitive to nuclear power plant. To keep nuclear energy as a main energy source, integrity of steam generator should be demonstrated. Quantitative relationship between ECT(eddy current test) signal and crack size is needed in assesment of integrity of steam generator in pressurized water reactor. However, it is not fully established for application in industry. Retired steam generator of Kori 1 has many kinds of crack such as circumferential and axial primary water stress corrosion crack and outer diameter stress corrosion crack(ODSCC). So, it can be used in qualifying and improving ECT technology and in condition monitoring assesment for crack detected in ISI(in service inspection). In addition, examination of pulled tube of Kori 1 retired steam generator will give information about effectiveness of non welded sleeving technology which was employed to repair defect tubes and remedial action which was applied to mitigate ODSCC. In this project, hardware such as semi hot lab. for pulled tube examination and modification transportation cask for pulled tube and software such as procedure of transportation of radioactive steam generator tube and non-destructive and destructive examination of pulled tube were established. Non-destructive and destructive examination of pulled tubes from Kori 1 retired steam generator were performed in semi hot lab. Remedial actions applied to Kori 1 retired steam generator, PWSCC trend and bulk water chemistry and crevice chemistry in Kori 1 were evaluated. Electrochemical decontamination technology for pulled tube was developed to reduce radiation exposure and enhance effectiveness of pulled tube examination. Multiparameter algorithm developed at ANL, USA was

  6. Cutting device for a local power range monitor tube

    International Nuclear Information System (INIS)

    Watanabe, Shigeru; Tsuji, Teruaki.

    1976-01-01

    Object: To provide a combination of a lifting device for a local power range monitor (LPRM) tube, a cutter and a transfer machine to safely and securely cut the LPRM tube under water. Structure: An LPRM tube is gripped by an LPRM tube gripper, which is moved up and down by a chain drive, through a flexture corrector, and the tip of the LPRM tube is held and released from the LPRM tube gripper so as to be threaded into an LPRM tube cutter to grip it by a transfer gripper of an LPRM tube transfer machine, after which the LPRM tube cutter is operated under pressure water to cut the LPRM tube with a cutter edge so that a cut portion is closed. (Yoshino, Y.)

  7. Enhanced Evaporation and Condensation in Tubes

    Science.gov (United States)

    Honda, Hiroshi

    A state-of-the-art review of enhanced evaporation and condensation in horizontal microfin tubes and micro-channels that are used for air-conditioning and refrigeration applications is presented. The review covers the effects of flow pattern and geometrical parameters of the tubes on the heat transfer performance. Attention is paid to the effect of surface tension which leads to enhanced evaporation and condensation in the microfin tubes and micro-channels. A review of prior efforts to develop empirical correlations of the heat transfer coefficient and theoretical models for evaporation and condensation in the horizontal microfin tubes and micro-channels is also presented.

  8. Lava tubes - Potential shelters for habitats

    Science.gov (United States)

    Horz, F.

    Natural caverns occur on the moon in the form of 'lava tubes', which are the drained conduits of underground lava rivers. The inside dimensions of these tubes measure tens to hundreds of meters, and their roofs are expected to be thicker than 10 meters. Consequently, lava tube interiors offer an environment that is naturally protected from the hazards of radiation and meteorite impact. Further, constant, relatively benign temperatures of -20 C prevail. These are extremely favorable environmental conditions for human activities and industrial operations. Significant operational, technological, and economical benefits might result if a lunar base were constructed inside a lava tube.

  9. Tubing For Sampling Hydrazine Vapor

    Science.gov (United States)

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

    1993-01-01

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

  10. Horizontal beam tubes in FRM-II

    International Nuclear Information System (INIS)

    Coors, D.; Vanvor, D.

    2001-01-01

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

  11. Early Experience with the StopLoss Jones Tube.

    Science.gov (United States)

    Bagdonaite, Laura; Pearson, Andrew R

    2015-06-01

    Extrusion is the most common reason for failure after Jones tube placement. The StopLoss Jones tube (SLJT) is a new innovation in Jones tubes that incorporates a flexible silicone internal flange to resist extrusion. We present our early experience of using this new tube and associated introducer system. We retrospectively analysed the case notes of a single surgeon consecutive series of patients having SLJT placement from November 2011 to November 2013. 29 SLJTs were placed in 25 eyes of 19 patients. Tube follow-up ranged from 1-25 months (mean 10 months) with a total of 291 tube-months. The indications for SLJT placement were: previous LJT complications (52%), failed canalicular-DCR surgery (31%), primary placement for inoperable canalicular occlusion (14%) and patent non-functioning DCR (3%). Tube length ranged from 10-16 mm. The tube introducer system was simple and effective and there were no intra-operative complications. The tube extrusion rate was 0%. Complications occurred in 5 tubes: 1 was too long, and 4 others (14%) developed conjunctival overgrowth/medial tube migration. Patient satisfaction with the tube was: 86% fully satisfied, 10% was moderately satisfied, 3% not satisfied. The overall final surgical success rate at last follow-up was 92%. In this short follow-up initial study the SLJT is simple to use and has a high rate of success and patient satisfaction. The addition of the internal silicone flange appears to prevent the previously common problem of extrusion.

  12. Mini implant supported molar tubes: A novel method for attaching the molar tubes

    Directory of Open Access Journals (Sweden)

    Nitin V Muralidhar

    2017-01-01

    Full Text Available Banding or bonding procedures have been the only means of attaching molar tubes onto the permanent molar teeth till date in the field of orthodontics. This clinical innovation aims to include the use of mini implant for the purpose of attaching the molar tubes thereby eliminating the iatrogenic effects of banding and bonding of the teeth.

  13. Heat removal capability of divertor coaxial tube assembly

    International Nuclear Information System (INIS)

    Shibui, Masanao; Nakahira, Masataka; Tada, Eisuke; Takatsu, Hideyuki

    1994-05-01

    To deal with high power flowing in the divertor region, an advanced divertor concept with gas target has been proposed for use in ITER/EDA. The concept uses a divertor channel to remove the radiated power while allowing neutrals to recirculate. Candidate channel wall designs include a tube array design where many coaxial tubes are arranged in the toroidal direction to make louver. The coaxial tube consists of a Be protection tube encases many supply tubes wound helically around a return tube. V-alloy and hardened Cu-alloy have been proposed for use in the supply and return tubes. Some coolants have also been proposed for the design including pressurized He and liquid metals, because these coolants are consistent with the selection of coolants for the blanket and also meet the requirement of high temperature operation. In the coaxial tube design, the coolant area is restricted and brittle Be material is used under severe thermal cyclings. Thus, to obtain the coaxial tube with sufficient safety margin for the expected fusion power excursion, it is essential to understand its applicability limit. The paper discusses heat removal capability of the coaxial tube and recommends some design modifications. (author)

  14. Conditioning and breakdown phenomena in accelerator tubes

    International Nuclear Information System (INIS)

    Skorka, S.J.

    1979-01-01

    Important breakdown mechanisms in accelerator tubes are reviewed, and discharge phenomena in NEC tubes are deduced from the surface appearance of the electrodes and insulators of a used tube. Microphotos of these surfaces are shown

  15. Simulation studies on Tube End Expansion of AA2014 Alloy Tubes

    Science.gov (United States)

    Venugopal, L.; Prasad, N. E. C.; Geeta Krishna, P.; Praveen, L.

    2018-03-01

    End forming is defined as forming the end of tubular forms either by inverting the tube or by expanding it. It finds application in many fields such as in automotive and aerospace sectors as power transmission elements, fuel lines, exhaust pipes etc. The main aim of the present work is to expand the AA2014 alloy tubes with different die sets without any fracture. Deform 2D software was used for performing simulations on expanding the tubes with different die set (punch) values having differed forming angles (α = 15°, 30° and 45°) and expansion ratios (rp/r0 = 1.39, 1.53 and 1.67). Experiments were also conducted and the results correlate with the simulation results. The results shows that for the punch having less cone angle (α) values the linear displacement is more rather than higher cone angles. But in the case of higher cone angles the radial displacement is more than the linear displacement.

  16. 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)

  17. Break size effect on the transient thermal-hydraulic behavior during the steam generator tube rupture accident

    International Nuclear Information System (INIS)

    Kang, K.H.; Park, H.S.; Cho, S.; Choi, N.H.; Chu, I.C.; Yun, B.J.; Kim, K.D.; Kim, Y.S.; Baek, W.P.; Choi, K.Y.

    2011-01-01

    In order to simulate the SGTR accident of the APR1400, integral effect tests were performed by simulating a double-ended rupture of a single and five U-tubes. Following the reactor trip, the primary system pressure decreased and the secondary system pressure increased until the MSSVs was opened to reduce the secondary system pressure. Break area affected the timings of the major events observed in the tests. Less heat transfer to the secondary side caused by earlier actuation of the safety injection pumps had more influence on the secondary pressure of the affected steam generator than the break flow. (author)

  18. Drift tubes of Linac 2

    CERN Multimedia

    Photographic Service

    1977-01-01

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

  19. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... Amblyopia Listen NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration Amblyopia Animations Blindness Cataract Convergence ... is maintained by the NEI Office of Science Communications, Public Liaison, and Education. Technical questions about this ...

  20. Measurement of unsteady flow forces in inline and staggered tube bundles with fixed and vibrating tubes

    International Nuclear Information System (INIS)

    Michel, A.; Heinecke, E.; Decken, C.B. von der.

    1986-01-01

    Unsteady flow forces arising in heat exchangers with cross-flow may lead to serious vibrations of the tubes. These vibrations can destroy the tubes in the end supports or in the baffles, which would require expensive repairs. The flow forces reach unexpectedly by high values if the vibration of the tube intensifies these forces. To clear up this coupling mechanism the flow forces and the vibration amplitude were measured simultaneously in a staggered and in an inline tube bundle. Considering the tube as a one-mass oscillator excited by the flow force, the main parameters can be derived, i.e. dynamic pressure, reduced mass, eigenfrequency and damping. These parameters form a dimensionless model number describing the coherence of the vibration amplitude and the force coefficient. The validity of this number has been confirmed by varying the test conditions. With the aid of this model number, the expected force coefficient can be calculated and then using a finite-element program information can be obtained about mechanical tensions and the lifetime of the heat exchanger tubes. With this model number the results of other authors, who measured the vibration amplitude only, could be confirmed in good agreement. The experiments were carried out in air with Reynolds numbers 10 4 5 . (orig.) [de

  1. French steam generator tubes: an overview of degradations

    International Nuclear Information System (INIS)

    Buisine, D.; Bouvier, O. de; Rupa, N.; Thebault, Y.; Barbe, V.; Pitner, P.

    2011-01-01

    The various damages (corrosion, fatigue cracks, wear, ...) observed on steam generator (SG) tubes are presented here as well as the techniques used to characterize these damages. The SG are equipped with tubes of 3 materials: 600 MA, 600 TT and 690 TT. Concerning PWSCC of 600 MA and 600 TT tubes, beyond the damages usually observed (corrosion in expansion transition zone and in 600 MA tubes small radius U-bend zone), a new event is to be noted: the phenomenon of denting (presumably induced by the deposit of sludge on the tubesheet) has induced circumferential cracking of the tube expansion transition zone. Concerning ODSCC of 600 MA tubes, beyond the classically observed damages (IGA and IGSCC in expansion transition zone and in TSP crevice), a new event is to be noted: the occurrence of circumferential cracks in tube- TSP crevice. Concerning fatigue cracking, two events have to be noted at upper TSP level in Cruas 1 and Cruas 4 units and in Fessenheim 2 unit. The first (Cruas) was due to the blockage in the broached hole tube support plate which can create critical velocity ratios for some tubes and the second (Fessenheim) to high-cycle fatigue. Concerning wear damage, beyond what is usually observed in the U-bend zone facing the anti-vibration bars (AVB), a new event is to be noted: a wear at TSP level is observed on SG equipped with an economizer, the wear indications being located at TSP 7 and 8 level, on outer tubes close to the central lane. The number of tubes plugged for ODSCC has declined due to the progressive replacement of SG with Alloy 600 MA tubing. Starting in 2004, the increasing plugging of 690 tubing is mainly due to AVB wear. Since 2006, extensive preventive plugging campaigns for tubes at risk of high-cycle fatigue at the upper support plate are performed. Risk of high-cycle fatigue has consequently become the dominant mechanism inducing plugging. PWSCC is the second dominant mechanism which affects 600 MA and 600 TT tube bundles: extensive

  2. Fluid mechanics and heat transfer spirally fluted tubing

    Science.gov (United States)

    Larue, J. C.; Libby, P. A.; Yampolsky, J. S.

    1981-08-01

    The objective of this program is to develop both a qualitative and a quantitative understanding of the fluid mechanics and heat transfer mechanisms that underlie the measured performance of the spirally fluted tubes under development at General Atomic. The reason for the interest in the spirally fluted tubes is that results to date have indicated three advantages to this tubing concept: The fabrication technique of rolling flutes on strip and subsequently spiralling and simultaneously welding the strip to form tubing results in low fabrication costs, approximately equal to those of commercially welded tubing. The heat transfer coefficient is increased without a concomitant increase of the friction coefficient on the inside of the tube. In single-phase axial flow of water, the helical flutes continuously induce rotation of the flow both within and without the tube as a result of the effect of curvature. An increase in condensation heat transfer on the outside of the tube is achieved. In a vertical orientation with fluid condensing on the outside of the helically fluted tube, the flutes provide a channel for draining the condensed fluid.

  3. Tubing Cutter is Activated Hydraulically

    Science.gov (United States)

    Mcsmith, D. G.; Richardson, J. I.

    1983-01-01

    Hydraulically-actuated tubing cutter severs tubing when operator squeezes handle grip. "Gooseneck" extension enables cutter to be used in areas where accessiblity is limited. Cutter has potential as flight-line tool and is useful in automobile and fire rescue work.

  4. Is tube feeding futile in advanced dementia?

    Science.gov (United States)

    Lynch, Matthew C.

    2016-01-01

    It is controversial whether tube feeding in people with dementia improves nutritional status or prolongs survival. Guidelines published by several professional societies cite observational studies that have shown no benefit and conclude that tube feeding in patients with advanced dementia should be avoided. However, all studies on tube feeding in dementia have major methodological flaws that invalidate their findings. The present evidence is not sufficient to justify general guidelines. Patients with advanced dementia represent a very heterogeneous group, and evidence demonstrates that some patients with dementia benefit from tube feeding. However, presently available guidelines make a single recommendation against tube feeding for all patients. Clinicians, patients, and surrogates should be aware that the guidelines and prior commentary on this topic tend both to overestimate the strength of evidence for futility and to exaggerate the burdens of tube feeding. Shared decision making requires accurate information tailored to the individual patient's particular situation, not blanket guidelines based on flawed data. Lay Summary: Many doctors believe that tube feeding does not help people with advanced dementia. Scientific studies suggest that people with dementia who have feeding tubes do not live longer or gain weight compared with those who are carefully hand fed. However, these studies are not very helpful because of flaws in design, which are discussed in this article. Guidelines from professional societies make a blanket recommendation against feeding tubes for anyone with dementia, but an individual approach that takes each person's situation into account seems more appropriate. Patients and surrogates should be aware that the guidelines on this topic tend both to underestimate the benefit and exaggerate the burdens of tube feeding. PMID:27833208

  5. Formability of Micro-Tubes in Hydroforming

    International Nuclear Information System (INIS)

    Hartl, Christoph; Anyasodor, Gerald; Lungershausen, Joern

    2011-01-01

    Micro-hydroforming is a down-scaled metal forming process, based on the expansion of micro-tubes by internal pressurization within a die cavity. The objective of micro-hydroforming is to provide a technology for the economic mass production of complex shaped hollow micro-components. Influence of size effects in metal forming processes increases with scaling down of metal parts. Investigations into the change in formability of micro-tubes due to metal part scaling down constituted an important subject within the conducted fundamental research work. Experimental results are presented, concerning the analysis of the formability of micro-tubes made from stainless steel AISI 304 with an outer diameter of 800 μm and a wall thickness of 40 μm. An average ratio of tube wall thickness to grain size of 1.54 of up to 2.56 was analyzed. Miniaturised mechanical standard methods as well as bulge tests with internal hydrostatic pressurization of the tubular specimens were applied to analyze the influence of size-dependent effects. A test device was developed for the bulge experiments which enabled the pressurization of micro-tubes with internal pressures up to 4000 bar. To determine the attainable maximum achievable expansion ratio the tubes were pressurized in the bulge tests with increasing internal pressure until instability due to necking and subsequent bursting occurred. Comparisons with corresponding tests of macro-tubes, made from the here investigated material, showed a change in formability of micro-tubes which was attributed to the scaling down of the hydroforming process. In addition, a restricted applicability of existing theoretical correlations for the determination of the maximum pressure at bursting was observed for down-scaled micro-hydroforming.

  6. Improved drainage with active chest tube clearance.

    Science.gov (United States)

    Shiose, Akira; Takaseya, Tohru; Fumoto, Hideyuki; Arakawa, Yoko; Horai, Tetsuya; Boyle, Edward M; Gillinov, A Marc; Fukamachi, Kiyotaka

    2010-05-01

    This study was performed to evaluate the efficacy of a novel chest drainage system. This system employs guide wire-based active chest tube clearance to improve drainage and maintain patency. A 32 Fr chest tube was inserted into pleural cavities of five pigs. On the left, a tube was connected to the chest canister, and on the right, the new system was inserted between the chest tube and chest canister. Acute bleeding was mimicked by periodic infusion of blood. The amount of blood drained from each chest cavity was recorded every 15 min for 2 h. After completion of the procedure, all residual blood and clots in each chest cavity were assessed. The new system remained widely patent, and the amount of drainage achieved with this system (670+/-105 ml) was significantly (P=0.01) higher than that with the standard tube (239+/-131 ml). The amount of retained pleural blood and clots with this system (150+/-107 ml) was significantly (P=0.04) lower than that with the standard tube (571+/-248 ml). In conclusion, a novel chest drainage system with active tube clearance significantly improved drainage without tube manipulations. 2010 Published by European Association for Cardio-Thoracic Surgery. All rights reserved.

  7. Testing and analysis of tube voltage and tube current in the radiation generator for mammography

    International Nuclear Information System (INIS)

    Jung, Hong Ryang; Hong, Dong Hee; Han, Beom Hui

    2014-01-01

    Breast shooting performance management and quality control of the generator is applied to the amount of current IEC(International Electrotechnical Commission) 60601-2-45 tube voltage and tube current are based on standards that were proposed in the analysis of the test results were as follows. Tube voltage according to the value of the standard deviation by year of manufacture from 2001 to 2010 as a 42-3.15 showed the most significant, according to the year of manufacture by tube amperage value of the standard deviation to 6.38 in the pre-2000 showed the most significant , manufactured after 2011 the standard deviation of the devices, the PAE(Percent Average Error) was relatively low. This latest generation device was manufactured in the breast of the tube voltage and tube diagnosed shooting the correct amount of current to maintain the performance that can be seen. The results of this study as the basis for radiography diagnosed breast caused by using the device's performance and maintain quality control, so the current Food and Drug Administration 'about the safety of diagnostic radiation generator rule' specified in the test cycle during three years of self-inspection radiation on a radiation generating device ensure safety and performance of the device using a coherent X-ray(constancy) by two ultimately able to keep the radiation dose to the public to reduce the expected effect is expected

  8. Dishevelled 2 is essential for cardiac outflow tract development, somite segmentation and neural tube closure.

    Science.gov (United States)

    Hamblet, Natasha S; Lijam, Nardos; Ruiz-Lozano, Pilar; Wang, Jianbo; Yang, Yasheng; Luo, Zhenge; Mei, Lin; Chien, Kenneth R; Sussman, Daniel J; Wynshaw-Boris, Anthony

    2002-12-01

    The murine dishevelled 2 (Dvl2) gene is an ortholog of the Drosophila segment polarity gene Dishevelled, a member of the highly conserved Wingless/Wnt developmental pathway. Dvl2-deficient mice were produced to determine the role of Dvl2 in mammalian development. Mice containing null mutations in Dvl2 present with 50% lethality in both inbred 129S6 and in a hybrid 129S6-NIH Black Swiss background because of severe cardiovascular outflow tract defects, including double outlet right ventricle, transposition of the great arteries and persistent truncus arteriosis. The majority of the surviving Dvl2(-/-) mice were female, suggesting that penetrance was influenced by sex. Expression of Pitx2 and plexin A2 was attenuated in Dvl2 null mutants, suggesting a defect in cardiac neural crest development during outflow tract formation. In addition, approximately 90% of Dvl2(-/-) mice have vertebral and rib malformations that affect the proximal as well as the distal parts of the ribs. These skeletal abnormalities were more pronounced in mice deficient for both Dvl1 and Dvl2. Somite differentiation markers used to analyze Dvl2(-/-) and Dvl1(-/-);Dvl2(-/-) mutant embryos revealed mildly aberrant expression of Uncx4.1, delta 1 and myogenin, suggesting defects in somite segmentation. Finally, 2-3% of Dvl2(-/-) embryos displayed thoracic spina bifida, while virtually all Dvl1/2 double mutant embryos displayed craniorachishisis, a completely open neural tube from the midbrain to the tail. Thus, Dvl2 is essential for normal cardiac morphogenesis, somite segmentation and neural tube closure, and there is functional redundancy between Dvl1 and Dvl2 in some phenotypes.

  9. [How to do - the chest tube drainage].

    Science.gov (United States)

    Klopp, Michael; Hoffmann, Hans; Dienemann, Hendrik

    2015-03-01

    A chest tube is used to drain the contents of the pleural space to reconstitute the physiologic pressures within the pleural space and to allow the lungs to fully expand. Indications for chest tube placement include pneumothorax, hemothorax, pleural effusion, pleural empyema, and major thoracic surgery. The most appropriate site for chest tube placement is the 4th or 5th intercostal space in the mid- or anterior- axillary line. Attention to technique in placing the chest tube is vital to avoid complications from the procedure. Applying the step-by-step technique presented, placement of a chest tube is a quick and safe procedure. Complications - frequently occurring when the tube is inserted with a steel trocar - include hemothorax, dislocation, lung lacerations, and injury to organs in the thoracic or abdominal cavity." © Georg Thieme Verlag KG Stuttgart · New York.

  10. Design of high voltage power supply of miniature X-ray tube based on resonant Royer

    International Nuclear Information System (INIS)

    Liu Xiyao; Zeng Guoqiang; Tan Chengjun; Luo Qun; Gong Chunhui; Huang Rui

    2013-01-01

    Background: In recent years, X rays are widely used in various fields. With the rapid development of national economy, the demand of high quality, high reliability, and high stability miniature X-ray tube has grown rapidly. As an important core component of miniature X-ray tube, high voltage power supply has attracted wide attention. Purpose: To match miniature, the high voltage power supply should be small, lightweight, good quality, etc. Based on the basic performance requirements of existing micro-X-ray tube high voltage power supply, this paper designs an output from 0 to -30 kV adjustable miniature X-ray tube voltage DC power supply. Compared to half-bridge and full-bridge switching-mode power supply, its driving circuit is simple. With working on the linear condition, it has no switching noise. Methods: The main circuit makes use of DC power supply to provide the energy. The resonant Royer circuit supplies sine wave which drives to the high frequency transformer's primary winding with resultant sine-like high voltage appearing across the secondary winding. Then, the voltage doubling rectifying circuit would achieve further boost. In the regulator circuit, a feedback control resonant transistor base current is adopted. In order to insulate air, a silicone rubber is used for high pressure part packaging, and the output voltage is measured by the dividing voltage below -5 kV. Results: The stability of circuit is better than 0.2%/6 h and the percent of the output ripple voltage is less than 0.3%. Keeping the output voltage constant, the output current can reach 57 μA by changing the size of load resistor. This high voltage power supply based on resonant Royer can meet the requirement of miniature X-ray tube. Conclusions: The circuit can satisfy low noise, low ripple, low power and high voltage regulator power supply design. However, its efficiency is not high enough because of the linear condition. In the next design, to further reduce power consumption, we

  11. Experimental investigation of shock wave diffraction over a single- or double-sphere model

    Science.gov (United States)

    Zhang, L. T.; Wang, T. H.; Hao, L. N.; Huang, B. Q.; Chen, W. J.; Shi, H. H.

    2017-01-01

    In this study, the unsteady drag produced by the interaction of a shock wave with a single- and a double-sphere model is measured using imbedded accelerometers. The shock wave is generated in a horizontal circular shock tube with an inner diameter of 200 mm. The effect of the shock Mach number and the dimensionless distance between spheres is investigated. The time-history of the drag coefficient is obtained based on Fast Fourier Transformation (FFT) band-block filtering and polynomial fitting of the measured acceleration. The measured peak values of the drag coefficient, with the associated uncertainty, are reported.

  12. A Study on Thermal Performance of a Novel All-Glass Evacuated Tube Solar Collector Manifold Header with an Inserted Tube

    Directory of Open Access Journals (Sweden)

    Jichun Yang

    2015-01-01

    Full Text Available A novel all-glass evacuated tube collector manifold header with an inserted tube is proposed in this paper which makes water in all-glass evacuated solar collector tube be forced circulated to improve the performance of solar collector. And a dynamic numerical model was presented for the novel all-glass evacuated tube collector manifold header water heater system. Also, a test rig was built for model validation and comparison with traditional all-glass evacuated tube collector. The experiment results show that the efficiency of solar water heater with a novel collector manifold header is higher than traditional all-glass evacuated tube collector by about 5% and the heat transfer model of water heater system is valid. Based on the model, the relationship between the average temperature of water tank and inserted tube diameter (water mass flow has been studied. The results show that the optimized diameter of inserted tube is 32 mm for the inner glass with the diameter of 47 mm and the water flow mass should be less than 1.6 Kg/s.

  13. 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.

  14. Schizophrenia on YouTube.

    Science.gov (United States)

    Nour, Matthew M; Nour, Murraih H; Tsatalou, Olga-Maria; Barrera, Alvaro

    2017-01-01

    YouTube ( www.youtube.com ) is the most popular video-sharing Web site on the Internet and is used by medical students as a source of information regarding mental health conditions, including schizophrenia. The accuracy and educational utility of schizophrenia presentations on YouTube are unknown. The purpose of this study was to analyze the accuracy of depictions of psychosis in the context of a diagnosis of schizophrenia (referred to in this article as "acute schizophrenia") on YouTube and to assess the utility of these videos as educational tools for teaching medical students to recognize the clinical features of acute schizophrenia. YouTube was searched for videos purporting to show acute schizophrenia. Eligible videos were independently rated by two consultant psychiatrists on two separate occasions 22 days apart for diagnostic accuracy, psychopathology, and educational utility. Videos (N=4,200) were assessed against predefined inclusion and exclusion criteria. The majority were not eligible for further analysis, mostly because they did not claim to show a patient with schizophrenia (74%) or contained duplicated content (11%). Of 35 videos that met the eligibility and adequacy criteria, only 12 accurately depicted acute schizophrenia. Accurate videos were characterized by persecutory delusions (83%), inappropriate affect (75%), and negative symptoms (83%). Despite the fact that 83% of accurate videos were deemed to have good educational utility compared with 15% of inaccurate videos, accurate and inaccurate videos had similar view counts (290,048 versus 186,124). Schizophrenia presentations on YouTube offer a distorted picture of the condition.

  15. Computation and measurement of calandria tube sag in PHWR

    International Nuclear Information System (INIS)

    Kim, Tae Ryong; Sohn, Seok Man

    2003-01-01

    Calandria tubes and liquid injection shutdown system (LISS) tubes in a pressurized heavy water reactor (PHWR) is known to sag due to irradiation creep and growth during plant operation. When the sag of calandria tube becomes bigger, the calandria tube possibly comes in contact with LISS tube crossing beneath and calandria tube. The contact subsequently may cause the damage on the calandria tube resulting in unpredicted outage of the plant. It is therefore necessary to check the gap between the two tubes in order to periodically confirm no contact by using a proper measure during the plant life. An ultrasonic gap measuring probe assembly which can be inserted into two viewing ports of the calandria was developed in Korea and utilized to measure the sags of both tubes in the PHWR. It was found that the centerlines of calandria tubes and liquid injection shutdown system tubes can be precisely detected by ultrasonic wave. The gaps between two tubes were easily obtained from the relative distance of the measured centerline elevations of the tubes. Based on the irradiation creep equation and the measurement data, a computer program to calculate the sags was also developed. With the computer program, the sag at the end of plant life was predicted. (author)

  16. Wolsong 3 and 4 steam generator tube inspection

    International Nuclear Information System (INIS)

    Jang, Kyoung Sik; Son, Tai Bong; Kwon, Dong Ki; Choi, Jin Hyuk

    2001-01-01

    During the pre-service inspection for Wolsong unit 3 and 4 in 1997/1998 respectively, 17 distorted roll transition indications (over expanded beyond tubesheet secondary face) were identified at the unit 4 (S/G B, D). Six(6) tubes out of these tubes were plugged in 1998. However the first periodic inspection identified additional 110 indications in 1999 and 2000. The additionally identified 110 indication call, not reported at the pre-service inspection, are; 2 not-finally-expanded-tubes and 108 distorted roll transition tubes. Design limit of each steam generator tube plugging is 6.4.%. Plugging was performed by the steam generator manufacturer under the warranty. When distorted roll transition indications were first identified on the unit 4 in 1998 the degree of over-expansion was measured using an inner dial-gage to make the disposition of nonconformance report. 2 Not-finally-expanded-tubes were plugged and 10 tubes out of 108 distorted roll transition tubes were also plugged as a preventive measure

  17. Resonant oscillations in open axisymmetric tubes

    Science.gov (United States)

    Amundsen, D. E.; Mortell, M. P.; Seymour, B. R.

    2017-12-01

    We study the behaviour of the isentropic flow of a gas in both a straight tube of constant cross section and a cone, open at one end and forced at or near resonance at the other. A continuous transition between these configurations is provided through the introduction of a geometric parameter k associated with the opening angle of the cone where the tube corresponds to k=0. The primary objective is to find long-time resonant and near-resonant approximate solutions for the open tube, i.e. k→ 0. Detailed analysis for both the tube and cone in the limit of small forcing (O(ɛ 3)) is carried out, where ɛ 3 is the Mach number of the forcing function and the resulting flow has Mach number O(ɛ ). The resulting approximate solutions are compared with full numerical simulations. Interesting distinctions between the cone and the tube emerge. Depending on the damping and detuning, the responses for the tube are continuous and of O(ɛ ). In the case of the cone, the resonant response involves an amplification of the fundamental resonant mode, usually called the dominant first-mode approximation. However, higher modes must be included for the tube to account for the nonlinear generation of higher-order resonances. Bridging these distinct solution behaviours is a transition layer of O(ɛ 2) in k. It is found that an appropriately truncated set of modes provides the requisite modal approximation, again comparing well to numerical simulations.

  18. Separately removable tubes in heavy duty heat exchanger assemblies

    International Nuclear Information System (INIS)

    Neudeck, G.T.

    1980-01-01

    The invention is directed to removable heat exchanger tube assemblies in heavy duty equipment radiators in which the tubes are each separately removable if they become defective in service. An inwardly facing annular ledge or abutment is molded into the inside diameter of each upper and lower sealing member to receive the respective ends of the tubes and prevent vertical movement of the tubes in service. A flange or shoulder is also provided on the lower portions of each tube and engages the inside of the lower sealing member to further restrain downward movement of the tubes in service. Each tube may be removed by pushing the tube upwardly to overcome the upper ledge abutment and thereby lift the tube free of the lower seal. Each tube may then be removed sidewise from the radiator. Variations of the removable sealing arrangement can be made and are described herein

  19. Survival period after tube feeding in bedridden older patients.

    Science.gov (United States)

    Kosaka, Yoichi; Nakagawa-Satoh, Takuma; Ohrui, Takashi; Fujii, Masahiko; Arai, Hiroyuki; Sasaki, Hidetada

    2012-04-01

    We prospectively studied survival periods after tube feeding. Participants were 163 bedridden older patients suffering from dysphagia. A wide range of survival periods after tube feeding were observed within half a year without tube feeding after being bedridden. After this initial period, survival periods after tube feeding were limited to approximately half a year. Survival periods after tube feeding were positively proportional to the length of time patients were free from pneumonia after tube feeding. After tube feeding, patients died from pneumonia within half a year, and the frequency of pneumonia was 3.1 ± 2.7 times (mean ± SD) before death. Survival periods after tube feeding for less than 1 year were primarily determined by being bedridden for more than half a year without tube feeding and once pneumonia occurred; patients who were tube fed did not survive for more than half a year. © 2012 Japan Geriatrics Society.

  20. The Functionality of Paratexts on YouTube

    DEFF Research Database (Denmark)

    Simonsen, Thomas Mosebo

    2014-01-01

    This chapter investigates paratexts and their functionality on YouTube. It is argued that YouTube content is in fact characterized by its dependence and usage of paratexts as part of YouTube's infrastructure. Paratexts are presented as being either auto-generated by YouTube or created by its users....... They are furthermore identified through a distinction between spatial and temporal relationships. Based on these distinctions, a small survey of some of the most popular videos on YouTube is conducted in order to examine the appearance and functionality of paratexts. A principal argument of the chapter...... is that the functionality of the paratexts can be explained by what Genette characterizes as the paratext's illocutionary force, which is examined in relationship to YouTube's paratexts and, more specifically, the site's implementation of links. The chapter also argues that paratexts may be characterized as a necessary...