Journal articles: 'Double tube'

1

Yang, Lian, Yong Hong Huang, and Liu Zhang. "Study on Engineering Construction with Three-Dimensional Heat Transfer Modeling for Double U-Tube Heat Exchangers in Ground-Source Heat Pump Systems." Advanced Materials Research 700 (May 2013): 231–34. http://dx.doi.org/10.4028/www.scientific.net/amr.700.231.

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There are many ground source heat pumps in engineering construction application. However, Research on heat exchanger models of single-hole buried vertical ground source heat pump mostly focuses on single U-tube ground heat exchangers other than double U-tube ones in China currently. Compared with single U-tubes, double U-tubes have the heat transfer particularity of asymmetry. Therefore, the use of the traditional single tube models would have large error in the simulation of the actual double U-tube heat exchangers. This paper frames a three-dimensional heat transfer model for the vertical single-hole buried double u-tube heat exchanger in a ground source heat pump system. The model considers the performance of U-bube material and uses a dual coordinate system and makes the control elemental volumes superimposed.

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Hartman, William R., Michael Brown, and James Hannon. "Iatrogenic Left Main Bronchus Injury following Atraumatic Double Lumen Endotracheal Tube Placement." Case Reports in Anesthesiology 2013 (2013): 1–3. http://dx.doi.org/10.1155/2013/524348.

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Tracheobronchial disruption is an uncommon but severe complication of double lumen endotracheal tube placement. The physical properties of a double lumen tube (large external diameter and length) make tracheobronchial injury more common than that associated with smaller single lumen endotracheal tubes. Here we present the case of an iatrogenic left main bronchus injury caused by placement of a double lumen tube in an otherwise unremarkable airway.

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Russell, W. J., and T. S. Strong. "Dimensions of Double-Lumen Tracheobronchial Tubes." Anaesthesia and Intensive Care 31, no. 1 (February 2003): 50–53. http://dx.doi.org/10.1177/0310057x0303100109.

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The diameter of the left main bronchus is the determining dimension when selecting the size of a left tracheobronchial (double-lumen) tube for lung separation. However, this information is not given by any manufacturer, either on the tube or in the package insert. This paper describes the lengths and diameters of the deflated bronchial cuff segment of left tracheobronchial tubes in common use. One hundred and seventy-one left tracheobronchial tubes ranging in size from 28 to 41 nominal French gauge from four manufacturers were measured. There was wide variation between tubes of the same nominal size from the same manufacturer. For tubes of the same size from the same manufacturer, the diameter of the segment with the deflated bronchial cuff varied by more than 1 mm in diameter in some instances.The diameter of the bronchial cuff segment did not consistently decrease as the nominal size decreased even for the same manufacturer. There was major overlap in diameters of the bronchial segments between Fr 41, Fr 39, and Fr 37 tubes from most manufacturers, so that some of the Fr 39 tubes have a bronchial cuff segment diameter as much as 0.5 mm larger than the Fr 41 tube. It is concluded that the current French gauge markings on left tracheobronchial tubes are of very limited value in determining the appropriate size to be selected for a patient. More accurate and consistent dimensions of tracheobronchial tubes are required to improve clinical selection.

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Hegland, Niels, Sebastian Schnitzler, Jan Ellensohn, Marc P. Steurer, Markus Weiss, and Alexander Dullenkopf. "Dimensional Variations of Left-Sided Double-Lumen Endobronchial Tubes." Anesthesiology Research and Practice 2019 (September 24, 2019): 1–9. http://dx.doi.org/10.1155/2019/3634202.

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Background. Tube size selection is critical in ventilating patients’ lungs using double-lumen endobronchial tubes (DLTs). Little information about relevant parameters is readily available from manufacturers. The aim of this study is to provide reference data for relevant dimensions of conventionally available DLTs. Methods. In this study in a benchmark in vitro setup, several dimensional parameters of four sizes of left-sided double-lumen endobronchial tubes from six different manufacturers were assessed, such as distances and diameters of tube shaft, cuff lengths, and diameters as well the angle at the tip. Results. Endobronchial tubes of ostensibly the same size revealed wide variation in measured parameters between brands from different manufacturers. In some parameters, there was an overlap between different sizes from the same manufacturer, i.e., diameters and distances did not increase with increasing nominal endobronchial tube size. The information about dimensions of endobronchial tubes provided by manufacturers’ leaflets is insufficient. Conclusions. Endobronchial tube size selection carries unnecessary uncertainty because clinically relevant parameters are unknown and vary considerably between different manufacturers.

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Zhang, Bing, Jun-Liang Zhao, Tao Huang, Ning-Yuan Zhang, Yi-Jie Zhang, and Xia-Min Hu. "Effect of fiber angles on hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns under monotonic axial compression." Advances in Structural Engineering 23, no. 7 (January 2, 2020): 1487–504. http://dx.doi.org/10.1177/1369433219895916.

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Hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns are a novel form of hollow columns that combine two traditional construction materials (i.e. concrete and steel) with fiber-reinforced polymer composites. Hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns consist of an inner tube made of steel, an outer tube made of fiber-reinforced polymer, and a concrete layer between the two tubes. Existing studies, however, are focused on hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns with fibers of the fiber-reinforced polymer tube oriented in the hoop direction or close to the hoop direction. In order to investigate the effect of fiber angles (i.e. the fiber angle between the fiber orientation and the longitudinal axis of the fiber-reinforced polymer tube), monotonic axial compression tests were conducted on hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns with an fiber-reinforced polymer tube of ±45°, ±60°, or ±80° fiber angles. There were two types of steel tubes adopted for these hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns. The fiber-reinforced polymer tube thickness was also investigated as an important parameter. Experimental results showed that the confinement effect of the fiber-reinforced polymer tube increased with the increase of the absolute value of fiber angles, whereas the ultimate axial strain of hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns decreased with the increase of the absolute value of fiber angles. An existing stress–strain model, which was developed on the basis of hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns with an fiber-reinforced polymer tube of ±90° fiber angles, is verified using the test results of this study. For the compressive strength of the confined concrete in hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns, the existing model provides conservative predictions for specimens with a ±80° fiber-reinforced polymer tube, overestimated predictions for specimens with a ±60° fiber-reinforced polymer tube, and close predictions for specimens with a ±45° fiber-reinforced polymer tube.

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Zhong, T., W. Wang, J. Chen, L. Ran, and D. A. Story. "Sore Throat or Hoarse Voice with Bronchial Blockers or Double-Lumen Tubes for Lung Isolation: A Randomised, Prospective Trial." Anaesthesia and Intensive Care 36, no. 6 (November 2008): 441–46. http://dx.doi.org/10.1177/0310057x0803600601.

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Double-lumen endotracheal tubes and bronchial blockers allow lung isolation for one-lung ventilation. Few studies, however, directly compare these devices. Further, a new endobronchial blocker (Coopdech) is available in some countries. Our primary hypothesis was that bronchial blockers would be associated with less sore throat or hoarse voice than double-lumen tubes. Secondary outcomes were successful one-lung ventilation and surgical access. In this prospective trial, 120 Chinese patients undergoing elective surgery were randomly assigned to one of four groups of 30 patients: Coopdech blocker, Arndt blocker, Univent tube or double-lumen tube. Postoperative sore throat and hoarse voice were assessed in the recovery room and 24 hours after surgery. The incidence and severity of sore throat or hoarse voice was less in the blocker groups than double-lumen tube group: Coopdech 13%, Arndt 20%, Univent 30% and double-lumen tube 60%, P <0.001. The blocker groups did not significantly differ, P=0.28. Compared to the double-lumen tubes the bronchial blockers took about two minutes less to position but five minutes longer for lung deflation. Surgical exposure was uniformly good across the four groups. We conclude that clinical use of the Coopdech endobronchial blocker is similar to the Arndt and Univent blockers and that all three are associated with less sore throat or hoarse voice than double-lumen tubes.

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Jeon, Y., H. G. Ryu, J. H. Bahk, C. W. Jung, and J. M. Goo. "A New Technique to Determine the Size of Double-lumen Endobronchial Tubes by the Two Perpendicularly Measured Bronchial Diameters." Anaesthesia and Intensive Care 33, no. 1 (February 2005): 59–63. http://dx.doi.org/10.1177/0310057x0503300109.

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The cross-section of the mainstem bronchi is not completely round. For preoperative selection of a double-lumen endobronchial tube size, it may be necessary to measure the mediolateral and the anteroposterior bronchial diameters, which can be measured respectively on chest radiograph and computed tomography. With Internal Review Board approval and patients’ informed consent, 105 elective thoracic surgical patients who needed left-sided double-lumen tubes were enrolled. Double-lumen tube size was selected depending on the arithmetic mean of the mediolateral and anteroposterior bronchial diameters. Moreover, the outer diameters of the bronchial tube should be smaller than both mediolateral and anteroposterior diameters. The recommended bronchial diameter for each double-lumen tube size was chosen so that the mean of the two bronchial diameters was 0 to 2.0 mm larger than the upper limit of 95% confidence interval of the averaged outer diameter of the bronchial tube of the selected double-lumen tube. In no case was the predicted double-lumen tube size inappropriate. Generally, anteroposterior bronchial diameters appeared to be different from mediolateral diameters (P=0.001). The double-lumen tube size to be selected based on only one bronchial diameter was different from the one selected based on two perpendicularly measured bronchial diameters in 54.3% of patients (57/105). Preoperative selection of the double-lumen tube size based on the anteroposterior, mediolateral and mean bronchial diameters seems to be useful in that this may obviate the need to change an inappropriately sized double-lumen tube and may be helpful in reducing the related complications.

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Abdul Razzaq, Ali K., and Khudheyer S. Mushatet. "A Numerical Study for a Double Twisted Tube Heat Exchanger." International Journal of Heat and Technology 39, no. 5 (October 31, 2021): 1583–89. http://dx.doi.org/10.18280/ijht.390521.

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The thermal and fluid physiognomies of a double twisted tube heat exchanger was examined numerically. Twisted engineering is a wide-use method to improve heat transfer in heat exchangers. A counter-flow mode utilizing hot water in the inner tube and cold air in the outer tube was considered. This study aims to progress the thermal performance of the double tube heat exchanger by using twisted tubes instead of plane tubes. The heat exchanger was (1m) length, outer diameter (0.05m) and inner diameter (0.025m), both with a thickness (0.004m). It was tested for different values of twist ratios (Tr= 5, 10, and 15 respectively) and Reynolds numbers (Re=5000 to 30000). The Navier - Stockes and energy equations besides the turbulence model in demand for modelling this physical problem. ANSYS Fluent code was used for the numerical simulation. The results showed that the twisted tube heat exchanger showed increasing heat transfer compared with a plain tube heat exchanger. It was found that the cold outlet temperature, pressure drop and effectiveness are increased as the twist ratio increases.

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Jaggar, Siân, Ali Mofeez, and Elizabeth Haxby. "Double-lumen tube audit." Journal of Cardiothoracic and Vascular Anesthesia 16, no. 6 (December 2002): 790–91. http://dx.doi.org/10.1016/s1053-0770(02)70004-9.

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Lohser, Jens, and Jay B. Brodsky. "Silbronco Double-Lumen Tube." Journal of Cardiothoracic and Vascular Anesthesia 20, no. 1 (February 2006): 129–31. http://dx.doi.org/10.1053/j.jvca.2005.03.035.

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Javed, Muhammmad Faisal, Haris Rafiq, Mohsin Ali Khan, Fahid Aslam, Muhammad Ali Musarat, and Nikolai Ivanovich Vatin. "Axial Behavior of Concrete-Filled Double-Skin Tubular Stub Columns Incorporating PVC Pipes." Crystals 11, no. 12 (November 23, 2021): 1434. http://dx.doi.org/10.3390/cryst11121434.

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This experimental study presents concrete-filled double-skin tubular columns and demonstrates their expected advantages. These columns consist of an outer steel tube, an inner steel tube, and concrete sandwiched between two tubes. The influence of the outer-to-inner tube dimension ratio, outer tube to thickness ratio, and type of inner tube material (steel, PVC pipe) on the ultimate axial capacity of concrete-filled double-skin tubular columns is studied. It is found that the yield strength of the inner tube does not significantly affect the ultimate axial capacity of concrete-filled double-skin tubular composites. With the replacement of the inner tube of steel with a PVC pipe, on average, less than 10% strength is reduced, irrespective of size and dimensions of the steel tube. Hence, the cost of a project can be reduced by replacing inner steel tubes with a PVC pipes. Finally, the experimental results are compared with the existing design methods presented in AISC 360-16 (2016), GB51367 (2019), and EC4 (2004). It is found from the comparison that GB51367 (2019) gives better results, followed by AISC (2016) and EC4 (2004).

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Park, H. P., J. H. Bahk, J. H. Park, and Y. S. Oh. "Use of a Fogarty Catheter as a Bronchial Blocker through a Single-lumen Endotracheal Tube in Patients with Subglottic Stenosis." Anaesthesia and Intensive Care 31, no. 2 (April 2003): 214–16. http://dx.doi.org/10.1177/0310057x0303100215.

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One-lung ventilation can be achieved with a double-lumen tube or a bronchial blocker. However, the larger outer diameters of double-lumen or Univent tubes may prevent their passage through an area of subglottic stenosiss. We present five cases of subglottic stenosis in which a Fogarty catheter was used as a bronchial blocker through a single-lumen endotracheal tube. The outer diameters of a double-lumen tube, Univent tube and single-lumen tube were compared. Despite special equipment designed for one-lung ventilation, the use of a bronchial blocker through a single-lumen tube, which has the thinnest available wall thickness, seems to be one of the most effective and safest ways of achieving one-lung ventilation in patients with subglottic stenosis or narrowing.

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Dhiwakar, M., G. I. Nambi, T. V. Ramanikanth, S. M. Kale, and M. N. Sivakumar. "Single cannula versus double cannula tracheostomy tubes in major oral and oropharyngeal resections." Journal of Laryngology & Otology 130, no. 4 (December 28, 2015): 388–92. http://dx.doi.org/10.1017/s0022215115003412.

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AbstractObjective:To compare the outcomes of two types of tracheostomy tubes used in major head and neck surgery.Methods:A retrospective study was conducted of prospectively collected data. The post-operative safety and adequacy of a single cannula tracheostomy tube was compared to a double cannula tracheostomy tube in patients undergoing tracheostomy during major oral and oropharyngeal resections.Results:Out of 46 patients with the single cannula tube, 7 (15 per cent) experienced significant obstruction warranting immediate tube removal, while another 9 (20 per cent) needed a change of tube or tube re-insertion for continued airway protection. In contrast, out of 50 patients with the double cannula tube, the corresponding numbers were 0 (p = 0.004) and 1 (2 per cent; p = 0.007) respectively.Conclusion:Insertion of a double cannula (instead of a single cannula) tracheostomy tube in the course of major oral and oropharyngeal resections offers better airway protection during the post-operative period.

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Eldawlatly, Abdelazeem A., Mohamed R. El Tahan, Naveed U. Kanchi, Ahmad Al Qatari, and Abdulaziz E. Ahmad. "Efficacy of height-based formula to predict insertion depth of left-sided double lumen tube: A prospective observational study." Anaesthesia and Intensive Care 48, no. 5 (September 2020): 354–57. http://dx.doi.org/10.1177/0310057x20946051.

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The insertion depth of the left-sided double-lumen tube needs careful positioning and bronchoscopic confirmation. Several formulae based on body height have been used for estimating the optimal insertion depth of a left-sided double-lumen tube. We conducted this prospective study to test the hypothesis that our earlier developed height-based formula (0.25 × body height0.916) could predict the accurate insertion depth of a left-sided double-lumen tube. After obtaining ethical approval, 66 patients who underwent thoracic surgery were included. A left-sided double-lumen tube was advanced blindly to the predicted depth of insertion calculated using our formula. The optimal position of the left-sided double-lumen tube was confirmed using a fibreoptic bronchoscope. The primary outcome was the percentage of tubes placed in the optimal position without the need for further adjustments. The secondary outcomes included the need for bronchoscopic adjustments and the final correct insertion depth of the left-sided double-lumen tube. The formula resulted in an optimum position of the left-sided double-lumen tube without further adjustments in 45 patients (70%) (95% confidence interval 58%–80%). The left-sided double-lumen tube was withdrawn or advanced in 18.2% and 12.1%, respectively, to achieve the optimal insertion depth. We found that our formula provided satisfactory positioning in about 70% of patients and that in the remaining patients, the adjustments required to achieve satisfactory positioning under fibreoptic bronchoscope guidance were minimal. Nevertheless, as it is not possible to predict which patients will have a satisfactory tube position, bronchoscopic confirmation for the final positioning is still required.

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Brodsky, J. B., A. Macario, W. B. Cannon, and J. B. D. Mark. "“Blind” Placement of Plastic Left Double-Lumen Tubes." Anaesthesia and Intensive Care 23, no. 5 (October 1995): 583–86. http://dx.doi.org/10.1177/0310057x9502300509.

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A prospective analysis of placement of left-sided plastic double-lumen tubes in 100 patients is presented. Intubation of the left bronchus was successfully accomplished using only auscultation and clinical signs (“blind” placement) in 91 patients. Double-lumen tubes were positioned in less than five minutes in 84 patients. The most common problem encountered (30%) was initial intubation of the right main bronchus. Seven of these patients required bronchoscopic assistance to guide the tube into the left bronchus. There were four minor intraoperative complications due to DLT malposition that were recognized and corrected by withdrawing the tube slightly back in the bronchus. The plastic double-lumen tubes functioned properly during the procedure in all 100 patients.

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AHMED, SHAFAQ, M. Tariq, SARFRAZ JANJUA, Hasan Raza, and M. ISHAQ. "DOUBLE LUMEN INTUBATION." Professional Medical Journal 16, no. 01 (March 10, 2009): 105–8. http://dx.doi.org/10.29309/tpmj/2009.16.01.2991.

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Introduction: Auscultation is well established and most commonly used method for checking of correct placement ofDouble Lumen Tube(DLT). Now with widespread availability of fibre optic bronchoscope, confirmation of DLT placement by fibre opticbronchoscope is recommended by many and considered mandatory by some anaesthetist. Objective: To discuss method of insertion andreliability of auscultatory method to confirm correct placement of double lumen tubes. S t u d y d e s i g n : Observational. Place a n d d u r a t i o n:Combined Military Hospital Rawalpindi from 16th Nov 2003 to 13th July 2007. Material & M e t h o d s . We have performed about one thousandone hundred and fifty double lumen intubation without use of fibreoptic bronchoscope. Results: 85% of patients did not need any tubeadjustment during surgical procedure. Only 15% cases required tube adjustment intra-operatively. None of procedures were abandoneddue to double lumen tubes problems. C o n c l u s i o n : We conclude that auscultation is not that unreliable though not perfect method of DLTplacement. Use of fibreoptic bronchoscope is recommended but not mandatory for DLT placement. Anatomical malpositioning detected byfibre optic bronchoscope which according to some studies is 70 to 80% does not necessarily translate into physiological malfunctioning.

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Pfeiffer, R., F. Simon, H. Kuzmany, V. N. Popov, V. Zólyomi, and J. Kürti. "Tube–tube interaction in double-wall carbon nanotubes." physica status solidi (b) 243, no. 13 (November 2006): 3268–72. http://dx.doi.org/10.1002/pssb.200669176.

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Chen, Tsung Chia, and Jiun Ming Ye. "Finite-Element Analysis of the Double Lateral Compression of Clad Tube into a Symmetric Square-Tube." Advanced Materials Research 337 (September 2011): 332–35. http://dx.doi.org/10.4028/www.scientific.net/amr.337.332.

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The squaring process to shape a circular tube into a symmetric square clad tube is examined by a three-dimensional incremental elastic-plastic finite-element method based on an updated Lagrangian formulation. The effects of various parameters, such as geometric ratio R/t, strain hardening exponent n, friction coefficient μ, and the length of tube L, on the occurrence of collapse in the squaring process are discussed and interpreted in a theoretical manner. The findings show that geometric ratio is the major factor in the process of squaring circular tubes. When R/t=25, serious collapse is likely to appear. Aiming at circular tubes with geometric ratio R/t=25, this study proposes six analysis configurations for clad tubes to discuss the possibility of clad tubes avoiding collapse. The findings showed that clad tubes could effectively reduce the collapse ratio.

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Navickaitė, Kristina, Michael Penzel, Christian R. H. Bahl, and Kurt Engelbrecht. "Performance Assessment of Double Corrugated Tubes in a Tube-In-Shell Heat Exchanger." Energies 14, no. 5 (March 1, 2021): 1343. http://dx.doi.org/10.3390/en14051343.

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In this article, the performance of double corrugated tubes applied in a tube-in-shell heat exchanger is analysed and compared to the performance of a heat exchanger equipped with straight tubes. The CFD (computational fluid dynamics) analysis was performed considering a turbulent flow regime at several mass flow rates. It is observed that the double corrugated geometry does not have a significant impact on the pressure drop inside the analysed heat exchanger, while it has the potential to increase its thermal performance by up to 25%. The ε–NTU (effectiveness–number of transfer units) relation also demonstrates the advantage of using double corrugated tubes in tube-in-shell heat exchangers over straight tubes.

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RANJBARTOREH, ALI REZA, and GUOXIU WANG. "BENDING STABILITY OF INNER AND OUTER TUBES OF DOUBLE-WALLED CARBON NANOTUBE." International Journal of Nanoscience 08, no. 01n02 (February 2009): 9–13. http://dx.doi.org/10.1142/s0219581x0900558x.

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This paper considers the effects of bending moment on the structure of double-walled carbon nanotube (DWCNT). Two types of DWCNTs with almost the same aspect ratio (length/radius) are selected; also continuum modeling is utilized to study the bending stability of inner and outer tubes. As a result of the van der Waals interaction between adjacent tubes the critical bending moment of inner tube is higher than this moment of outer tube which is indicated from the obtained results of this research; thus, achieving higher reliability in nanostructures, the critical bending moment of outer tube should be taken into account.

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Zhang, Bing, Gui-Sen Feng, Yan-Lei Wang, Cong-Cong Lai, Chen-Chen Wang, and Xia-Min Hu. "Elliptical FRP-Concrete-Steel Double-Skin Tubular Columns under Monotonic Axial Compression." Advances in Polymer Technology 2020 (January 24, 2020): 1–16. http://dx.doi.org/10.1155/2020/7573848.

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Hybrid FRP-concrete-steel double-skin tubular columns (hybrid DSTCs) are a novel form of hollow columns consisting of an outer FRP tube, an inner steel tube, and an annular layer of concrete between the two tubes. Due to the effective confinement of the two tubes, the concrete in hybrid DSTCs is well confined, leading to excellent ductility and strength enhancement. Hybrid DSTCs also have excellent corrosion resistence due to the effective protection of the outer FRP tube. However, existing studies mainly focused on hybrid DSTCs with a circular cross-section. When subjecting to different loads in the two horizontal directions, elliptical columns are preferred as they can provide different bending stiffness and moment capacity around two axes of symmetry without significantly reducing the confining effect of the FRP tube. This paper extends the existing work on circular DSTCs to elliptical DSTCs with a particular focus on four issues: the effect of elliptical aspect ratio (i.e., the ratio of the major axis to the minor axis of the outer elliptical cross-section), the effect of the FRP tube thickness, the effect of void area ratio (i.e., the ratio of the area of concrete void to the area of the outer elliptical section), and the effect of the cross-section of the inner steel tube (i.e., both rectangular and elliptical steel tubes were used). Experimental results show that, the averaged peak stress of the confined concrete in elliptical DSTCs increases with the increase in the elliptical aspect ratio, whereas the elliptical aspect ratio has no obvious effect on the ultimate axial strain; the cross-section shape of the inner steel tube has significant effect on the axial stress-strain behavior of the confined concrete in elliptical DSTCs; elliptical DSTCs with an elliptical steel tube exhibit much better ductility and strength enhancement than those specimens with a rectangular steel tube. A simple stress-strain model of confined concrete was proposed for elliptical DSTCs to account for the effects of the elliptical aspect ratio, the inner void, and the shape of the inner steel tube, which can provide reasonably accurate but conservative predictions.

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Wang, Jian, Hong Tu Sun, and Jing Huang. "Improved Design of Thin-Walled Square Tube for Energy Absorption." Advanced Materials Research 460 (February 2012): 389–92. http://dx.doi.org/10.4028/www.scientific.net/amr.460.389.

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Thin-walled tubes are the main structures to absorb the energy in front impact at the desired controlled collision. A thin-walled square tube is designed by use of a double deck square tube with clapboards which has a stable structure with less Euler deformation in front impact. More deformations of extensional collapse in the double deck square tube with clapboards improve the performance of structures for energy absorption. Induced slots are employed in the square tube to decrease the peak acceleration in front impact. Collision process can be controlled by the slots for the stable deformation and reduced initial peak acceleration

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He, Shiquan, Linhao Wei, Jianfeng Lu, and Weilong Wang. "Heat transfer characteristics of molten salt flowing in steam generator." Thermal Science, no. 00 (2021): 225. http://dx.doi.org/10.2298/tsci210103225h.

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The paper respectively investigated the heat transfer characteristics of molten salt flowed in shell-and-tube and double-pipe steam generator. The shell-and-tube steam generator had seven tubes and molten salt flowed outside the tubes, while the double-pipe steam generator had two concentric tubes and molten salt flowed in the annular duct formed by two tubes. Inlet temperature of molten salt ranged from 270?C to 420?C. The experimental results showed the effect of temperature on heat transfer coefficient was more significant in the double-pipe steam generator compared to the shell-and-tube steam generator. The heat transfer coefficient firstly increased and then decreased as the increase of temperature. Further numerical study was conducted and the results showed, in the shell-and-tube steam generator, the flow is disturbed by the tube bundle and the boundary layer near the inner wall is deformed, so the temperature of molten salt cannot obviously affect the heat transfer. In the double-pipe steam generator, an opposite flow was generated in the near cooled wall region by the buoyancy force. When the inlet temperature was below 315?C, the velocity of the opposite flow was quite low. In this stage, the heat transfer coefficient increased with the increase of temperature. When the inlet temperature continues to rise to 390?C, the opposite flow was enhanced and a stable layer with low velocity formed between the mainstream and the inner cooled wall, resulting increase of heat transfer resistance and impairment of heat transfer coefficient.

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Hatamachi, Tsuyoshi, Tatsuya Kodama, Yuki Isobe, Daisuke Nakano, and Nobuyuki Gokon. "Double-Walled Reactor Tube with Molten Salt Thermal Storage for Solar Tubular Reformers." Journal of Solar Energy Engineering 128, no. 2 (April 8, 2005): 134–38. http://dx.doi.org/10.1115/1.2183803.

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This paper proposes a novel-type of “double-walled” reactor tube with molten-salt thermal storage at high temperatures for use in solar tubular reformers. The prototype reactor tube is demonstrated on the heat-discharge and chemical reaction performances during cooling mode of the reactor tube at laboratory scale. The Na2CO3 composite material with MgO ceramics was filled into the outer annulus of the double-walled reactor tube while the Ru-based catalyst particles were filled into the inner tube. The heat discharge form the molten Na2CO3 circumvented the rapid temperature change of the catalyst bed, which resulted in the alleviation of decrease in chemical conversion during cooling mode of the reactor tube. The application of the new reactor tubes to solar tubular reformers is expected to help realize stable operation of the solar reforming process under fluctuating insolation during a cloud passage.

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Brodsky, Jay B., and Alex Macario. "Modified bronchocath double-lumen tube." Journal of Cardiothoracic and Vascular Anesthesia 9, no. 6 (December 1995): 784–85. http://dx.doi.org/10.1016/s1053-0770(05)80265-4.

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Desai, F. M., and D. A. Rocke. "Double-lumen Tube Design Fault." Anesthesiology 73, no. 3 (September 1, 1990): 575. http://dx.doi.org/10.1097/00000542-199009000-00042.

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Fortier, G., D. Coté, J. Soucy, R. Lelièvre, and J. Bussières. "Left double lumen tube malposition." British Journal of Anaesthesia 93, no. 3 (September 2004): 475–76. http://dx.doi.org/10.1093/bja/aeh599.

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Komatsu, K., T. Arai, and Y. Hatano. "A modified double-lumen tube." Anaesthesia 43, no. 12 (February 22, 2007): 1064. http://dx.doi.org/10.1111/j.1365-2044.1988.tb05730.x.

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Fikkers, B. G., and D. F. Zandstra. "Incorrectly labelled double-lumen tube." Journal of Cardiothoracic and Vascular Anesthesia 8, no. 5 (October 1994): 605. http://dx.doi.org/10.1016/1053-0770(94)90184-8.

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30

Saito, Toshiyuki, Tsuguo Naruke, Edward Carney, Yoko Yokokawa, Kazuaki Hiraga, and Christer Carlsson. "New Double Intrabronchial Tube (Naruke Tube) for Tracheostomized Patients." Anesthesiology 89, no. 4 (October 1, 1998): 1038–39. http://dx.doi.org/10.1097/00000542-199810000-00037.

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31

Koca, Tarkan, and Aydın Citlak. "Design and analysis of double-pipe heat exchanger using both helical and rotating inner pipe." Thermal Science 25, no. 2 Part B (2021): 1545–59. http://dx.doi.org/10.2298/tsci201010066k.

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In this study, the effects of rotating straight and helical inner tubes is experimentally discussed to determine heat transfer and pressure losses in rotating tubes and improve heat transfer. The outer tube remains stationary and the inner tube is rotated at different speeds in the work. In the experiments for straight and helical tubes, the flow regime is turbulent. According to the results, Nusselt number, pressure loss, and efficiency of heat exchanger were gauged. In addition, empirical formulas were obtained for each pipe type. It is observed that as the rotation speed of the pipe increases, the heat transfer rate increases. The pipe that provides the best increase in heat transfer is the five helixes tubes. At five helixes tubes; after the number of revolutions per minute exceeds 300, the increase in heat transfer rate has almost halt. At five helixes tubes and at 300 rpm speed when the flow of cold water through the annular gap with the fluid passing through the inner tube is equal, the heat transfer increases by 124.10% compared to straight tube, 23.47% compared to two helixes tubes, 7.92% compared to three helixes tubes, and 1.65% compared to four helixes tubes. Maximum effectiveness was obtained while rotating with 300 rpm in five helixes pipes.

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Luo, Cheng, Xingyuan Huang, Tongke Liu, and Hesheng Liu. "Research on Inner Gas Inflation Improvements in Double-layer Gas-assisted Extrusion of Micro-tubes." Polymers 12, no. 4 (April 13, 2020): 899. http://dx.doi.org/10.3390/polym12040899.

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Micro-tubes have small diameters and thin wall thicknesses. When using double-layer gas-assisted extrusion (DGAE) technology to process micro-tubes, due to the influence of flow resistance, airflow from the inner gas-assisted layer cannot flow into the atmosphere through the lumen. Over time, it will inflate or even fracture the micro-tubes intermittently and periodically. To solve this problem, a new double-layer micro-tube gas-assisted extrusion die was designed in this study. Its mandrel has an independent airway leading to the lumen of the extrudate, with which the gas flow into the lumen of the extrudate can be regulated by employing forced exhaust. Using the new die, we carried out extrusion experiments and numerical calculations. The results show a significant positive correlation between micro-tube deformation and gas flow rate in the lumen of a micro-tube. Without considering the refrigerant distortion of the microtube, the flow rate of forced exhaust should be set equal to that of the gas from the inner gas-assisted layer flow into the micro-tube lumen. By doing this, the problem of the micro-tube being inflated can be eliminated without causing other problems.

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Zhang, Bing, Yu-Jun Qi, Tao Huang, Qian-Biao Zhang, Yu Hu, and Xia-Min Hu. "Effect of Fiber Angles on Hybrid Double-Tube Concrete Columns under Monotonic Axial Compression." Advances in Civil Engineering 2019 (December 20, 2019): 1–19. http://dx.doi.org/10.1155/2019/2363185.

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Hybrid double-tube concrete columns (hybrid DTCCs) are a novel form of hybrid columns that combine fiber-reinforced polymer (FRP) composites with two traditional construction materials (i.e., concrete and steel). Hybrid DTCCs consist of an outer FRP tube and an inner steel tube aligned concentrically, with the space between the two tubes and inside of the steel tube filled with concrete. The three materials (i.e., FRP, concrete, and steel) in hybrid DTCCs are combined optimally to deliver excellent performances, such as excellent ductility and remarkable corrosion resistance. Recently, hybrid DTCCs have received increasing research attention on their compressive behavior. Existing studies, however, are focused on hybrid DTCCs with fibers of the FRP tube oriented in the hoop direction or close to the hoop direction. Against this background, this paper presents a series of monotonic axial compression tests on hybrid DTCCs with a particular focus on the effect of fiber angles (i.e., the angle of the fiber orientations to the longitudinal axis of the FRP tube). Three types of fiber angles (i.e., ±45°, ±60°, or ±80°) and two FRP tube thicknesses (i.e., 4 mm and 8 mm) were employed in the present study. Experimental results show that the concrete in hybrid DTCCs is well confined by both the FRP tube and the steel tube, leading to excellent ductility; the confinement effect of the FRP tube increases with the increase of the absolute value of fiber angles, whereas the ultimate axial strain decreases with the increase of the absolute value of fiber angles. An existing analysis-oriented model, which considers the different confining states of the concrete between the two tubes and that inside of the steel tube, is verified using the present test results. The model is capable of providing accurate predictions for hybrid DTCCs with a ±80° FRP tube. For hybrid DTCCs with a ±45° or ±60° FRP tube, the model yields reasonable accurate predictions for the peak axial load but underestimates the ultimate axial strain consistently.

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Gao, J. Y., W. Q. Teng, J. F. Wang, and J. Xie. "Boiling simulation and PEC evaluation of helically corrugated tubes in vertical grooves with different pipe diameters." Journal of Physics: Conference Series 2047, no. 1 (October 1, 2021): 012013. http://dx.doi.org/10.1088/1742-6596/2047/1/012013.

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Abstract The double tube structure is simulated, R32 in the inner helical corrugated tubes with vertical grooves is heated by the water flowing in the outer tube to make it boil. The influence of pipe diameter and number of vertical grooves on the performance of double tube is analyzed. The evaporation temperature of the refrigerant is 283K. The temperatures of inlet refrigerant and inlet water are 280K and 320K, respectively. The flow velocity of inlet refrigerant and inlet water are 1m/s and 5m/s, respectively. The simulation results show that, compared with the smooth pipe, when the inner pipe diameter is 3, 4, 5, 6, 7mm, the surface heat transfer coefficients of the double tube have been increased by 160%, 150%, 147%, 138%, and 130%, respective. when PEC=1.691, the performance of the inner helical corrugated tube is the best, whose inner pipe diameter is 3 mm, outer pipe diameter is 6.2 mm, number of vertical grooves is 10.

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Wang, Bing, Lu Ma, and Xiao Liu. "Analysis on the Status of Concrete Filled Double Skin Steel Tubes Mechanical Properties." Applied Mechanics and Materials 488-489 (January 2014): 374–76. http://dx.doi.org/10.4028/www.scientific.net/amm.488-489.374.

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Concrete filled double skin steel tubes which is developed on the basis of concrete filled steel tube, it is a new member. Combination of Chinese and foreign literature, this paper comprehensively discusses the research results about concrete filled double skin steel tubes member, then put forward the further research work, for concrete filled double skin steel tubes structure in deeply study to play a guiding role.

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Krishnan, Annur Srinivasan, and Palanivelu Gowtham. "Computational study of Staggered and Double Cross Flow Heat Exchanger." Defence Science Journal 67, no. 4 (June 30, 2017): 396. http://dx.doi.org/10.14429/dsj.67.11427.

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The preliminary findings of a comparative study of heat transfer rate and pressure drop between conventional staggered flow and double cross flow heat exchanger is reported. Excepting for the tube arrangements, the shell and tube dimensions, materials and inlet conditions are retained the same for the two configurations. While in the conventional arrangement, adjacent rows of tubes are normal only to the fluid flow in the shell, in the double cross-flow arrangement, they are normal to both fluid flow direction in the shell as well as to each other. Shell dimensions are 100 cm × 20 cm × 20 cm and tube outside and inside diameters are 1 cm and 0.8 cm. The shell and tube materials are steel and copper. Water and air were considered as tube and shell side fluids respectively, with an overall arrangement of parallel flow. The tube flow Reynolds number was fixed at 2200 and the shell flow Reynolds number was varied from 20 to 120 in the laminar regime and 360 to 600 in the turbulent zone. The study reveals that the proposed configuration gives a maximum increase of about 27 per cent in the heat transfer rate per unit pressure drop over the conventional one.

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Tarrad, Ali H. "3D Numerical Modeling to Evaluate the Thermal Performance of Single and Double U-tube Ground-coupled Heat Pump." HighTech and Innovation Journal 3, no. 2 (February 19, 2022): 115–29. http://dx.doi.org/10.28991/hij-2022-03-02-01.

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The heat transfer rate and borehole design represent great challenges to the thermal equipment designer of the ground-coupled heat pump. The present model represents a mathematical and numerical technique implemented to tackle such a problem. A thermal assessment was established to estimate the total energy dissipated to the ground zone for a heat pump utilized for cooling purposes in the summer season. Comsol Multiphysics 5.4 software was used to build a 3-dimensional model to assess the thermal performance of single and double U-tube boreholes that circulate water as a thermal transfer medium. The (Heat Transfer) module has been implemented for this investigation under the (Stationary) study option. The model couples both heat conduction in solids, including tube metal, grout, and soil regions, and thermal medium fluid flow inside the U-tubes. The numerical solutions were compared for both heat exchangers at fixed borehole geometry, diameter, and depth and constant operating conditions in a steady-state mode. The double U-tube heat exchanger was tested in the parallel circuiting orientation of the U-tubes. The total mean resistance of the single U-tube borehole was higher than the half-loading double U-tube heat exchangers by 14.6%. The results also revealed that the heat transfer rate enhancement for the double U-tube was in the range of 10–14% when operating at the same fluid mass flow rate and inlet temperature for a given borehole design. Doi: 10.28991/HIJ-2022-03-02-01 Full Text: PDF

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38

Damude, Samantha, Anneke C. Muller Kobold, Esther Bastiaannet, Schelto Kruijff, Harald J. Hoekstra, and Kevin P. Wevers. "Double venipuncture is not required for adequate S-100B determination in melanoma patients." BioTechniques 69, no. 5 (November 2020): 371–78. http://dx.doi.org/10.2144/btn-2019-0147.

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S-100B is used in melanoma follow-up. This serum biomarker is also present in adipocytes; therefore, subcutaneous adipocytes trapped in the needle before performing a venipuncture could contaminate the serum. The aim was to study the influence of adipocyte contamination on blood samples used for S-100B analysis, possibly resulting in falsely elevated S-100B values. A total of 294 serum samples were collected from 147 American Joint Committee on Cancer staging stage III melanoma patients. The mean difference between the first (dummy) and second tubes was 0.003 μg/l (p = 0.077), with a decrease in the second tube. Compared with the second tube, the S-100B level was higher in the first tube in 33.3% of the samples, equal in 36.8% of the samples and lower in 29.9% of the samples. No significant difference between the two consecutively drawn tubes was found. There seems to be no necessity of implementing a dummy tube system for accurate S-100B determination in melanoma patients.

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39

Djamaluddin, F., Shahrum Abdullah, A. K. Arrifin, and Z. M. Nopiah. "Multi-Objective Optimization of Aluminum Foam Double Tube Subjected to Oblique Impact Loading for Automobile Bumper Beam." Applied Mechanics and Materials 663 (October 2014): 93–97. http://dx.doi.org/10.4028/www.scientific.net/amm.663.93.

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This paper presents the multi-objective optimization of aluminum foam double circular tube under oblique load for various load angle and geometry parameters. Thin-walled metallic tubes are used in vehicle structures to absorb impact energy, such as in bumper beams. In this research, aluminum alloy AA6063 T6 foam filled tube which both end were clamped, at bottom as boundary condition and at the top of tube applied quasi-static force of load angle of 0o to 30o with respect to longitudinal direction of tubes. The finite element analysis using ABAQUS code was validated according to the relevant experimental data, and the deformation modes of the tubes were studied. Multi-objective optimization design of crush parameters such as minimum peak crushing force and maximum specific energy absorption were performed using particle swarm optimization algorithm. Different optimal designs for different angles of loading and geometries of double circular tubes was identified.

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40

Manoj, M. Murali, and Mu Raajaram. "Endotracheal Tube Cuff Pressure Monitoring Prospective Double Blind Randomised Control Study." Indian Journal of Anesthesia and Analgesia 5, no. 7 (2018): 1146–50. http://dx.doi.org/10.21088/ijaa.2349.8471.5718.10.

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41

WEI, Xinyu, Chunhui DAI, Suxia HOU, yun TAI, and Fuyu ZHAO. "ICONE19-43034 Thermal Optimization of Primary Side in Double-Tube OTSG." Proceedings of the International Conference on Nuclear Engineering (ICONE) 2011.19 (2011): _ICONE1943. http://dx.doi.org/10.1299/jsmeicone.2011.19._icone1943_11.

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42

Ke, Zhang, Zhang Huijie, and Tang Zhiping. "Experimental study of thin-walled TiNi tubes under radial quasi-static compression." Journal of Intelligent Material Systems and Structures 22, no. 18 (October 19, 2011): 2113–26. http://dx.doi.org/10.1177/1045389x11426344.

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TiNi tubes with various sizes and boundary constraints subjected to radial quasi-static compression were systematically studied. The contour curves of the tubes were extracted from the real-time charge-coupled device (CCD) images, and the circumferential strain, bending moment, and phase composition distribution were calculated based on the contour curves and some assumptions. It was found that the load–displacement curves had hysteretic loops, and all specimens could recover to their initial shape after unloading, which was attributed to the effects of austenite–martensite phase transformation and phase transformation hinges (THs). For single-tube experiments, the numbers of TH were observed to be twice the numbers of constraints. For vertical double-tube experiments, the main deformation of each tube was concentrated on its upper half circle. The energy dissipation rate (EDR) and the dissipated specific energy (SE) in single-tube case increased with decrease of the diameter–wall thickness ratio (DTR; D/ t) or increase of the constraint number. With a four-directional constraint condition and same D/ t, the EDR and SE of vertical double tubes were greater than that of a single tube and close-packed seven tubes. The present results could give a reference for designing repeatedly used shock-resistant element with higher energy absorption capacity.

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43

Wei, Xinyu, Chunhui Dai, Li Wang, and Fuyu Zhao. "Inner tube optimization of double-tube once-through steam generator." International Journal of Heat and Mass Transfer 59 (April 2013): 93–102. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2012.11.058.

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44

Shakouchi, Toshihiko, Kazuma Yamamura, Koichi Tsujimoto, and Toshitake Ando. "Heat Transfer Enhancement of Circular- and Petal- Shaped Double-Tube-Type Heat Exchangers by Triple Ones." Energies 13, no. 24 (December 14, 2020): 6590. http://dx.doi.org/10.3390/en13246590.

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Conventional circular double or triple tube type heat exchanger, DHE or THE, is one of the compact heat exchangers; a large number of studies have been performed to improve their heat transfer performance. The authors demonstrated that a petal-shaped special DHE with a large wet perimeter yields a high heat transfer efficiency, η. In this study, the DHE with six or five petals-, five shallow petals-, and circular-inner tubes were used. To further improve the η of the DHE, a THE with a petal-shaped inner tube along with the middle and outer circular tubes were used. Hot water flowed through the inner tube and cold water flowed through the middle and outer tubes as a counter current flow. The heat transfer was approximately equal; however, the flow resistance (pressure loss) of the outer tube of the DHE could be decreased using the middle and outer tubes under the same amount of cold water as the DHE; consequently, the η could be improved. In addition, the effect of changing the flow path of the hot- and cold-water flows on the η was examined.

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45

Chen, Qi Wei, and Xin Ping Ouyang. "Experimental Study on Condensation of R134a inside Horizontal Inner-Micro-Fin Tubes." Advanced Materials Research 354-355 (October 2011): 753–58. http://dx.doi.org/10.4028/www.scientific.net/amr.354-355.753.

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An experimental study of condensation heat transfer of R134a on horizontal inner enhanced tubes was conducted. The tested tubes were inner-micro-fin tubes, named tube A and tube B, respectively. The tested pieces were double-pipe condensers. The glycol solution flowed in the space between outer surface of the enhanced tube and inner surface of outer tube. In the experiment, condensing temperature inside the enhanced tube was 51°C, and the flow velocity of glycol solution was 3.35m/s. The inlet temperature of glycol solution changed according to mass velocity of refrigerant, to maintain certain degree of undercooling of outlet refrigerant. The research showed that the condensation heat transfer coefficient of both tubes increased with the increasing mass velocity of refrigerant. when the mass velocity of refrigerant increased from 300kg/m2s to 700kg/m2s, the condensation heat transfer coefficient in tube A was 1.87% to 6.28% higher than that of tube B. However, the flow resistance of the refrigerant in tube B was 9.56% to 11.05% higher than in tube A. The structure of tube A was superior to that of tube B.

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46

Potocnik, Iztok, Andreas Kupsch, and Vesna Jankovic. "Iatrogenic rupture of the trachea caused by double Lumen tube intubation." Open Medicine 5, no. 6 (December 1, 2010): 737–41. http://dx.doi.org/10.2478/s11536-010-0046-1.

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AbstractAcute injuries of the tracheobronchial system are rare and life-threatening situations. Tracheal rupture most commonly occurs after blunt trauma to the chest. It is a rare but most concerning immediate complication of intubation. One-lung ventilation is required in lung surgery. Video assisted thoracoscopic procedures are an absolute indication for one-lung intubation. The double-lumen tube is the mainstay of one lung ventilation. Due to their larger size and rigidity, double lumen tubes are more difficult to insert, and complications are more common than with single lumen tubes. Opinions about the need for checking routinely the position of a double lumen tube by fiber optic bronchoscopy directly after intubation are divided. A 69-year-old woman with epidermoid lung carcinoma was scheduled for video assisted thoracoscopic left upper pulmonary lobectomy under general anaesthesia. The patient was prepared for the operation and itubated with the Carlens double lumen tube as usual. On introducing the camera into the thoracic cavity, the surgeon noted that the lungs were not completely collapsed. During blind adjustment the position of the tube the trachea was ruptured. The right-sided thoracotomy was performed and closed the greater part of the tracheal laceration. Only its upper 1.5-cm segment was surgically inaccessible because of the anatomical situation and thus remained unsutured. The patient received antibiotics, continuous airway humidification, analgesia with piritramide, and chest physiotherapy. She had no complications. In the literature, opinions about checking routinely the position of a double lumen tube by fiber optic bronchoscopy are divided.. Possibly, the very serious complication encountered in our patient could have been avoided, had the tube position been checked by bronchoscopy. The treatment strategy for post-intubation tracheal rupture depends on the size and location of the rupture, its clinical presentation, and the overall condition of the patient). Early surgical repair is the treatment of choice for most patients when a transmural tear with a length exceeding 2 cm. In our the combination of surgical and conservative treatment was performed. The uppermost part of the tear could not be sutured because of the anatomical situation, and so about 1.5 cm of the trachea remained open. The case is interesting from many perspectives. It shows that intubation with a Carlens tube is a potentially hazardous procedure, which should be performed only by experienced anaesthesiologists. Furthermore, our case report underscores the importance of checking routinely the position of a double lumen tube by fiber optic bronchoscopy. It provides evidence that minor tracheal lacerations can be successfully managed by conservative measures.

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Hong, Feng, Bin Wei, and Lin Chen. "Preliminary Study on Biosynthesis of Bacterial Nanocellulose Tubes in a Novel Double-Silicone-Tube Bioreactor for Potential Vascular Prosthesis." BioMed Research International 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/560365.

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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 withAcetobacter xylinum, and Kombucha, a symbiosis of acetic acid bacteria and yeasts. The results indicated that Kombucha gave higher yield and productivity of BNC thanA. 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.

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Cui, Xiao-Lei, Xiao-Song Wang, and SJ Yuan. "Further assessment of the plastic instability of thin-walled tubes in double-sided hydro-bulging process with verification experiments." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 233, no. 3 (November 6, 2017): 776–86. http://dx.doi.org/10.1177/0954405417738285.

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An interesting process of double-sided tube hydro-bulging was proposed to provide a beneficial three-dimensional stress state in the deformation zone of the tube, so as to delay the occurrence of bursting on the tube. Previously proposed forming limit theory models with consideration of through-thickness normal stress found that the external pressure could lead to a deferred occurrence of plastic instability, but it has not been confirmed experimentally. In this article, the tensile plastic instability of tubes under double-sided pressures is further assessed based on the classical plastic instability theory. However, it is seen that the occurrence of plastic instability has not found delay when high external pressure was exerted on the outside surface of tube simultaneously, which is opposite to the previous forming limit models. In addition, an experiment investigation about double-sided tube hydro-bulging is conducted to verify the theoretical results, and the experimental results show that the external pressure has hardly any influence on forming limit strain of the 2A12 aluminum alloy tube before the occurrence of necking. Moreover, the contradiction between our results and the previously proposed forming limit theory models is that the previous models ignored the thickness item in the equilibrium equation.

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Zheng, Yongqian, Cunhua Wang, and Manying Chen. "Flexural strength and stiffness of circular double-skin and double-tube concrete-filled steel tubes." Marine Structures 81 (January 2022): 103126. http://dx.doi.org/10.1016/j.marstruc.2021.103126.

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50

NAKAYAMA, Yoshito. "Essentials of Double Lumen Tube Extubation." JOURNAL OF JAPAN SOCIETY FOR CLINICAL ANESTHESIA 38, no. 2 (2018): 196–202. http://dx.doi.org/10.2199/jjsca.38.196.

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Journal articles on the topic 'Double tube'

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