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Letteratura scientifica selezionata sul tema "Bulges on the tube"

Autore: Grafiati

Pubblicato: 31 agosto 2024

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Articoli di riviste sul tema "Bulges on the tube"

Farley, F. J. M., R. C. T. Rainey e J. R. Chaplin. "Rubber tubes in the sea". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 370, n. 1959 (28 gennaio 2012): 381–402. http://dx.doi.org/10.1098/rsta.2011.0193.

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A long tube with elastic walls containing water is immersed in the sea aligned in the direction of wave travel. The waves generate bulges that propagate at a speed determined by the distensibility of the tube. If the bulge speed is close to the phase velocity of the waves, there is a resonant transfer of energy from the sea wave to the bulge. At the end of the tube, useful energy can be extracted. This paper sets out the theory of bulge tubes in the sea, and describes some experiments on the model scale and practical problems. The potential of a full-scale device is assessed.

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Liu, Yuyang, Yong Luan, Xinbo Dai, Senyun Liu, Xian Yi e Yu Rao. "A Numerical Study on Swirling Hot Air Anti-Icing with Various Surface Structures on the Internal Wall". Energies 16, n. 3 (20 gennaio 2023): 1179. http://dx.doi.org/10.3390/en16031179.

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Swirling hot air is a promising heat transfer enhancement technology for anti-icing applications in aircrafts, where the swirling flow is accompanied by pretty high turbulence and a quite thin boundary layer. It is of interest to investigate the compound heat transfer characteristics of the swirling air configuration combined with surface structures on the internal wall. This paper carries out a series of numerical computations to obtain the Nusselt number and pressure loss data in such a swirling air heat transfer system with four kinds of surface structures (trenches, ribs, dimples and bulges) on the wall and with different tangential inlet jets placed along the tube. At a tube Reynolds number from 10,000 to 50,000, the results show that the surface dimples and bulges are conducive to improving the Nusselt number, but the surface trenches and ribs show a Nusselt number deterioration relative to the smooth swirl tube. Among the four investigated surface structures, the surface bulges perform best, which can enhance the Nusselt number by up to 15.0%, increase the total heat transfer quantity by up to 17.3% and reduce the hot air pressure loss by up to 15.6%. Furthermore, the circumferential velocity distribution and swirl number are introduced to describe the flow fields. The surface trenches and ribs lead to less of a reduction in the circumferential velocity and swirl intensity, while the surface dimples and bulges could significantly suppress the in-tube swirl intensity.

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Wen, Hua Dian, Xiao Ting Xiao, Kai Zhang e Ying Chen. "Metal Flow Rule of Multi-Way Tube Hydro Forming for Air Handling Unit". Advanced Materials Research 239-242 (maggio 2011): 1597–600. http://dx.doi.org/10.4028/www.scientific.net/amr.239-242.1597.

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Multi-way tube on air conditioning header is considered as the research objective .Finite element simulation method is utilized to simulate and analyze the deformation process of metal. Through analyzing the distribution law of velocity on work piece neutral plane and displacement law of typical nodes, common law in deformation process for metal flow was revealed. Results suggested that: metal which is on terminal supplementary zone conspicuously flows along horizontal. Metal which is on forming zone conspicuously flows along bulge, metal which is between bulges flows little, these laws provide a reference for the choice of forming technology.

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Inoue, Tadanobu, Erina Kitahara, Yuka Hara e Koji Nakazato. "Mud Crab’s Mottled, Deep-Blue Exoskeleton: Surface Morphology and Internal Microstructure". Minerals 12, n. 12 (14 dicembre 2022): 1607. http://dx.doi.org/10.3390/min12121607.

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The claws of the mud crab, Scylla serrata, are huge in comparison with its body size. Many bulges ranging from 5 to 23 μm in height and 90 to 146 µm in diameter were observed on the mottled, deep-blue exoskeleton surface of the mud crab’s claw. These cuticle bulges were closely related to irregularly present exocuticles on the surface layer of the exoskeleton’s cross section. The bulges exist between the exocuticles, and at the apex of these bulges was a tube that bundled many pore canals that penetrated the exoskeleton. This tube was thick (62–66 µm) near the inner side and narrowed (12–22 µm) toward the outer surface. On the other hand, the exocuticles had a heterogeneous tissue structure in a coarse region extending normally to the surface, with a diameter of 3 to 7 µm, and a dense region between them. Calcium concentrations were high in the dense region, and phosphorus and magnesium concentrations were high in the coarse region. As a result, the mechanical properties (hardness: H and modulus: Er) were distributed inside the exocuticle, and the mapping of H and Er using a nanoindentation test clarified the heterogeneity.

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Chaplin, J. R., V. Heller, F. J. M. Farley, G. E. Hearn e R. C. T. Rainey. "Laboratory testing the Anaconda". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 370, n. 1959 (28 gennaio 2012): 403–24. http://dx.doi.org/10.1098/rsta.2011.0256.

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Laboratory measurements of the performance of the Anaconda are presented, a wave energy converter comprising a submerged water-filled distensible tube aligned with the incident waves. Experiments were carried out at a scale of around 1:25 with a 250 mm diameter and 7 m long tube, constructed of rubber and fabric, terminating in a linear power take-off of adjustable impedance. The paper presents some basic theory that leads to predictions of distensibility and bulge wave speed in a pressurized compound rubber and fabric tube, including the effects of inelastic sectors in the circumference, longitudinal tension and the surrounding fluid. Results are shown to agree closely with measurements in still water. The theory is developed further to provide a model for the propagation of bulges and power conversion in the Anaconda. In the presence of external water waves, the theory identifies three distinct internal wave components and provides theoretical estimates of power capture. For the first time, these and other predictions of the behaviour of the Anaconda, a device unlike almost all other marine systems, are shown to be in remarkably close agreement with measurements.

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Magin, Norbert, Regine Classen e Claudia Gack. "The morphology of false anthers in Craterostigma plantagineum and Torenia polygonoides (Scrophulariaceae)". Canadian Journal of Botany 67, n. 7 (1 luglio 1989): 1931–37. http://dx.doi.org/10.1139/b89-245.

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The ontogenesis of the prominent excrescences of the filament of two melittophilous species is investigated and the biological implications are discussed. In Craterostigma plantagineum Hochst. the bases of the filament bulges are fused with the lower lip of the corolla. The bulges are bright yellow, of grainy structure, and they flank the entrance of the flower tube. This character syndrome can be interpreted as a plastic (three-dimensional) false anther or anther dummy. The flower of Torenia polygonoides Benth. carries a yellow, spotlike anther dummy in the centre of the lower lip. The staminal excrescences of T. polygonoides are completely free of the lower lip of the corolla, pin-shaped, and of a light pink colour. Thus, they lack the characteristic, yellow signal colour that is typical for anther dummies in general. Possibly, they have no optical function at all, but act as a guide rail.

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Boonpuek, P., S. Jirathearanat e N. Depaiwa. "Flow Stress Determination of Steel Tube for Hydroformability Evaluation". Advanced Materials Research 622-623 (dicembre 2012): 656–60. http://dx.doi.org/10.4028/www.scientific.net/amr.622-623.656.

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This study aims to determine flow stress of a steel tube by using hydraulic bulge test. A new proposed analytical model for analyzing bulge shapes of hydroformed tubes is postulated. Bulge test apparatus designed using FEA simulation of hydroforming and STKM 11A steel tubes are used in the hydraulic bulge test. Bulge heights and internal pressures are measured during bulge testing. Tube thicknesses at vertex of a bulge shape are measured by a dial caliper gauge. Bulge curvatures and contact points are measured by taking digital photos of bulge shapes combined with measurement methods in CAD software. Effective stress - strain relationships are obtained from the newly developed analytical model using those measured values. Flow stress curves obtained from the effective stress – strain relationships are compared with those by other researchers and tensile test. Finite element analysis methods are used to conduct simulation of tube hydroforming using the flow stress curves. Predicted internal pressures versus bulge heights and tube thicknesses are compared with experimental results. Verification of the developed analytical model is presented. The flow stress at neck point of formed tube is determined.

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Hwang, Yeong-Maw, H. C. Chuang e B. J. Chen. "Hydraulic Bulge Tests of Magnesium Tubes at Elevated Temperatures". Advanced Materials Research 83-86 (dicembre 2009): 1135–42. http://dx.doi.org/10.4028/www.scientific.net/amr.83-86.1135.

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Evaluation of the formability of tubes is an important issue in tube hydroforming processes. Since tubular materials during tube hydroforming are under a biaxial even triaxial stress state, other biaxial-stress-based testing methods are needed. In this paper, uniaxial tensile tests at different temperatures are firstly employed to evaluate the material properties of magnesium alloy AZ61 tubes. A hydraulic bulge warm forming machine, which is used for hydraulic bulge tests with a fixed tube length, is also designed and manufactured. Using this self-designed testing machine, experiments of bulge tests of magnesium alloy AZ61 tubes at elevated temperatures are carried out. From the experimental results, the bulge formability of the magnesium alloy tubes at different temperatures is discussed.

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Opryshko, L. V., e T. V. Golovnyak. "Study of surface defects in tubes made from nondeformed continuously cast billets". Metaloznavstvo ta obrobka metalìv 98, n. 2 (7 giugno 2021): 54–62. http://dx.doi.org/10.15407/mom2021.02.054.

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Defects of outer and inner surfaces of hot-rolled tubes of various steel grades and sizes manufactured on tube-rolling unit with a continuous mill (TPA 30-102) at Interpipe Nikotube LLC from a nondeformed continuously cast billets produced by MZ Dniprostal LLC have been studied. Characteristic genetic and morphological signs of defects were revealed which makes it possible to reliably classify them, identify cause of defect formation and recommend measures to eliminate them. Defects on the outer and inner surfaces of tubes are of metallurgical origin and associated with quality of initial continuously cast billets (a consequence of violation of the smelting and continuous casting technology). Defects on the inner surface of tubes were caused on defects in the axial zone of original billets (unacceptable porosity, looseness, chemical inhomogeneity, liquation stripes and cracks, etc.) and are classified as steel-smelting films and bulges. It was found that displacement of the thermal center of crystallization (a feature of the machines for continuous steel casting of curvilinear type) had an additional negative effect on quality of the inner surface of the studied tubes. Defects on the outer surface of tubes are tears of burning in places of accumulation of low-melting inclusions and their eutectics, as well as steel-smelting scabs on rolled dirt and gas bubbles. Likelihood of formation of scabs on outer surface of the studied tubes over rolled crust introversions is not excluded. The study results will allow manufacturers to reliably classify defects, promptly reject tubes with unacceptable defects of metallurgical origin and minimize supply of low-quality products to consumers. These results will later be included in the classifier of defects in tubes manufactured on the TPA 30-102 unit from nondeformed continuously cast billets. The results of the study of natural signs of defects of metallurgical origin in the tube surface will be useful for elaboration of measures aimed at improvement of the technology of manufacturing initial tube billets. Keywords: tube surface defects, continuously cast billets, microstructure, rolled contamination, low-melting inclusions, eutectic, gas bubbles, decarburization, liquation.

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Mitsui, Satoshi, Taisuke Miyagawa, Hajime Yasui e Shoichiro Yoshihara. "Warm Bulge Forming of Small Diameter A1100 Aluminium Tube". Materials Science Forum 920 (aprile 2018): 149–54. http://dx.doi.org/10.4028/www.scientific.net/msf.920.149.

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In recent years, the small diameter aluminium tube has been widely utilized for chemical instruments and medical devices. These instruments are should be minimized since the usage of the small diameter tubes has been extremely increased. However, the deformation characteristics could not be scaled down similarly to the material dimensions due to the size effect. Thus, tube bulge forming is necessary to clarified the deformation characteristics of the small diameter tubes. In this paper, the formability of the warm tube bulge forming by using the small diameter A1100 aluminium tube with 2.0 mm outer diameter and 0.2 mm thickness has been investigated. As the results, the effect of the different temperature and the different internal pressure on the tube bulge forming of the small diameter A1100 aluminium tubes was clarified. Furthermore, it was confirmed that the variation of the internal pressure loading rate affected the deformation characteristics of the tubes.

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Più fonti

Tesi sul tema "Bulges on the tube"

Wu, Zhi-Qian. "Caveolin in membrane nanotubes : curvature sensing and bulge formation". Electronic Thesis or Diss., Université Paris sciences et lettres, 2024. http://www.theses.fr/2024UPSLS007.

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La cavéoline est l'un des principaux composants protéiques des cavéoles, qui sont de petites invaginations en forme de coupe dans la membrane plasmique. Il est synthétisé dans le réticulum endoplasmique d'une manière dépendante des particules de reconnaissance du signal et transporté vers l'appareil de Golgi via des vésicules recouvertes de COPII. Au niveau du réseau trans-Golgi (TGN), les complexes de cavéoline 8S s'oligomérisent davantage en complexes 70S avec la facilitation du cholestérol. Ils sont ensuite triés dans des transporteurs par un mécanisme inconnu et transportés vers la membrane plasmique. Le modèle structurel conventionnel de la cavéoline pourrait suggérer qu'il s'agit d'une protéine sensible à la courbure, basée sur sa forme moléculaire en épingle à cheveux. Cependant, un modèle de structure récemment découvert du complexe cavéoline 8S dans les micelles de détergent, basé sur la microscopie cryoélectronique, qui présente une géométrie de disque plat, soulève des questions sur sa sensibilité à la courbure. De plus, les cavins, un autre composant protéique majeur des cavéoles qui coopèrent avec les cavéolines pour plier la membrane pour former des cavéoles, ne s'associent pas aux cavéolines au niveau du TGN. Étant donné qu'aucun autre candidat connu, hormis les cavins, ne peut coopérer avec la cavéoline pour former des transporteurs au TGN, il devient difficile de savoir comment ces transporteurs de cavéoline y sont formés. Par conséquent, dans ce projet, nous avons cherché à élucider la sensibilité à la courbure et l’induction de la cavéoline. Nous avons résolu ces problèmes en reconstituant la cavéoline-1 (Cav1) dans la membrane de vésicules nilamellaires géantes (GUV) et en réalisant des expériences de tirage de tubes. Les résultats ont montré que la cavéoline est effectivement une protéine sensible à la courbure, les complexes de cavéoline 8S présentant une inclinaison d'environ 5 egrés par rapport à l'horizontale, ce qui leur confère une sensibilité à la courbure. De plus, nous avons montré que les complexes de cavéoline 8S peuvent générer collectivement une courbure de la membrane à basse tension et former des échafaudages sur les tubes à haute tension. En résumé, nos résultats ont montré que la cavéoline est une protéine détectant et induisant une courbure, suggérant la possibilité de son tri en transporteurs au TGN sur la base de ces propriétés. De manière intéressante, nous avons observé qu’au-dessus d’une certaine tension membranaire Tt qui dépend de la densité de Cav1, les nanotubes extraits des Cav1-GUV ne présentent plus un rayon constant et que les cavéolines forment des renflements sur le tube. Pour explorer comment Cav1 forme ces renflements, nous avons d'abord observé qu'en moyenne, la taille des renflements diminue avec l'augmentation de la tension membranaire. Nous avons constaté que la taille du renflement est proportionnelle à la quantité totale de cavéoline dans le renflement, ce qui suggère une densité Cav1 constante dans les renflements.De plus, une densité plus élevée de cavéoline dans la membrane favorise la formation de renflements et abaisse le Tt. Ces résultats suggèrent que lorsque le rayon du tube diminue, la cavéoline pourrait induire la formation de renflements pour relâcher les contraintes mécaniques dues à la géométrie tubulaire, mais un modèle et une imagerie haute résolution sont maintenant nécessaires pour expliquer ces observations
Caveolin is one of the major protein components of caveolae, which are small cup-shaped invaginations in the plasma membrane. It is synthesized in the endoplasmic reticulum in a signal recognition particle-dependent manner and transported to the Golgi apparatus via COPII-coated vesicles. At the trans-Golgi network (TGN), caveolin 8S complexes further oligomerize into 70S complexes with the facilitation of cholesterol. They are then sorted intotransport carriers through an unknown mechanism and transported to the plasma membrane. The conventional structural model of caveolin might suggest it is a curvature-sensing protein based on its hairpin molecular shape. However, a recently discovered structure model of the caveolin 8S complex in detergent micelles based on cryo-electron microscopy, which exhibits a flat disc geometry, raises questions about its curvature sensitivity.Furthermore, cavins, another major protein component of caveolae that cooperate with caveolins in bending the membrane to form caveolae, do not associate with caveolins at the TGN. Given that no other known candidate, apart from cavins, can cooperate with caveolin to form transport carriers at the TGN, it becomes unclear how these carriers for caveolin are formed there. Therefore, in this project, we aimed to elucidate the curvaturesensitivity and induction of caveolin. We addressed these issues by reconstituting caveolin-1 (Cav1) into the membrane of giant unilamellar vesicles (GUVs) and by performing tube-pulling experiments. The results showed that caveolin is indeed a curvature-sensing protein, with caveolin 8S complexes exhibiting approximately a 5 degree tilt from the horizontal, which endows them with curvature sensitivity. Furthermore, we showed that caveolin 8S complexes can collectively generate membrane curvature at low tension and form scaffolds on the tubes at high tension. In summary, our results showed that caveolin is a curvature-sensing and -inducing protein, suggesting the possibility of its sorting into transport carriers at the TGN based on these properties. Interestingly, we observed that above a certain membrane tension Tt that depends on Cav1 density, nanotubes pulled from Cav1-GUVs no longer exhibit a constant radius and that caveolins form bulges on the tube. To explore how Cav1 form these bulges, we first observed that on average, bulges' size decreases with an increase in membrane tension. We found that the bulge size is proportional to the total amount of caveolin in the bulge, suggesting a constant Cav1 density in the bulges. Additionally, higher density of caveolin in the membrane favors bulge formation and lowers Tt. These results suggest that when the tube radius decreases, caveolin might induce formation of bulges to relax mechanicalconstraints due to the tubular geometry, but a model and high resolution imaging are now needed to explain these observations

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Linardon, Camille. "Etirage de tubes de précision pour applications biomédicales : contribution à l'analyse et l'amélioration du procédé par expérimentation, modélisation et simulation numérique". Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00956588.

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Les tubes métalliques de précision sont largement utilisés pour des applications biomédicales. De tels tubes sont fabriqués par étirage à froid car ce procédé garanti le meilleur aspect de surface, le plus grand contrôle des dimensions du tube et le contrôle des propriétés mécaniques. L'objet de cette étude est de modéliser le procédé d'étirage de tube sur mandrin afin d'en améliorer la compréhension et de construire un outil permettant l'optimisation du procédé et de prédire la rupture des tubes en étirage. La construction du modèle élément finis s'appuie sur la réalisation d'essais expérimentaux afin de caractériser les propriétés mécaniques des matériaux et le frottement entre le tube et les outils d'étirage (mandrin, filière). Le comportement mécanique des alliages est caractérisé par des essais de traction sur tube, des essais de traction sur des éprouvettes découpées dans différentes orientations dans un tube déplié et des essais de gonflement de tube. Pour ces derniers, une machine et un outillage de gonflement de tubes ont été développés spécifiquement. Par le biais de ces essais différents aspects ont été étudiés : la viscoplasticité, l'anisotropie plastique, l'hétérogénéité des propriétés dans l'épaisseur du tube, la thermomécanique. Les coefficients de frottements ont été identifiés par analyse inverse sur des essais d'étirage instrumentés par des cellules d'effort. Des essais d'étirage ont été spécifiquement conçus en modifiant la géométrie du mandrin afin de conduire à la rupture des tubes lors de l'étirage. L'objectif de tels essais étant d'identifier la limite de formabilité des tubes. L'approche choisie pour prédire de la rupture a été d'utiliser des critères de ruptures qui pouvaient être calibrés sur des essais de traction uniquement. Les critères ont été calculés au cours de la simulation numérique de l'étirage sur mandrin et ils ont été évalués par rapport à leur capacité à prédire les réductions de section et d'épaisseur maximales. Enfin, des méthodes analytiques de calcul d'effort d'étirage ont été développées et comparées à la modélisation éléments finis.

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Voirand, Antoine. "Etude théorique de la dynamique d'une bulle dans un tube capillaire chauffé". Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2016. http://www.theses.fr/2016ESMA0008/document.

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Dans le cadre d’une contribution à la modélisation des caloducs oscillants, le modèle mis en place se résume à une bulle seule se déplaçant dans un tube de dimension capillaire.Une densité volumique de chaleur est considérée dans la paroi du capillaire, et la température de référence considérée n’est pas la température de saturation de la phase vapeur,mais la température extérieure au tube ce qui permet la variation de la température de saturation dans le temps et une meilleur adéquation du modèle avec la réalité. La résolution du modèle est effectuée par étapes selon la technique de perturbation du domaine,et les effets physiques de moindres importances peuvent être ajoutés au problème simplifié, en particulier les effets inertiels. Cette résolution a permis de définir une nouvelle corrélation portant sur la hauteur de film déposé par le bouchon liquide en mouvement en fonction du nombre capillaire et d’un nombre d’évaporation représentant l’intensité du chargement thermique. Ce modèle permettra aussi d’étudier l’influence réciproque des champs de vitesse et de température sur le bouchon de liquide devant le ménisque en déplacement. La résolution du problème associé à la partie arrière de la bulle met en évidence la formation d’un bourrelet de liquide entre le film de liquide déposé à la paroi et le ménisque arrière. La taille de ce bourrelet est fortement dépendante de la densité de flux de chaleur imposée à la paroi. Dans le cas o`u le ménisque arrière remouille un film adsorbé laissé à la paroi après assèchement du film, la ligne triple présente des ondulations axiales dues à son déplacement, et non au chargement thermique. La densité de flux de masse évaporée à l’interface liquide-vapeur entraîne une modification non seulement de la température de saturation, mais aussi de la masse de la bulle. Un modèle thermodynamique de la phase vapeur a ´et´e mis en place pour étudier les paramètres importants influençant les variations temporelles des caractéristiques géométriques et thermodynamiques de la bulle
The model of a single bubble moving in a capillary tube is written as a contribution to the modeling of Pulsating Heat Pipes. A constant heat load is considered at the wall, and the reference temperature of the problem is defined to be the outside medium temperature, which is closer to reality, and thus allowing the saturation temperature of the vapor phase to vary. Using domain perturbation techniques, a step-by-step resolution ofthe model is implemented, allowing minor physical effects to be taken into consideration,for example the inertial effect on the receding meniscus. A new correlation is proposed on the thickness of the liquid film deposited by the receding meniscus, by means of the capillary number and an evaporation number representing the thermal condition. The velocity and temperature fields in the liquid plug ahead of the meniscus can also be obtained. The resolution of the problem associated with the rear-end of the bubble,where the rear meniscus advances on either a micrometric liquid film or an adsorbed film left by the dry-out of the capillary wall, shows a corrugating liquid-vapor interface.The magnitude of these corrugations is strongly dependent on the value of the heat load applied at the wall. In the case of wall rewetting, the interface corrugations at the triple line are due to its displacement, and not to the thermal boundary condition. Because the evaporative mass flux through the liquid-vapor interface modifies the vapor bubble mass, a complete transient thermodynamical model of the bubble is implemented. In this case, the important parameters controlling the kinematics, dynamics and thermodynamics of the bubble were identified

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Hervieu, Eric. "Ecoulement monophasique et diphasique à bulles dans un branchement en Té : étude théorique et expérimentale". Grenoble INPG, 1988. http://www.theses.fr/1988INPG0031.

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Etude de la separation des phases. Description potentielle de la structure de l'ecoulement monophasique. Modelisation des recirculations dans le te a l'aide de la theorie de la ligne de jet et d'une methode des singularites. Etude experimentale par anemometrie laser doppler, traitement d'images, attenuation de rayon x

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Touhami, Kamel. "Contribution a l'etude des ecoulements diphasiques dans un tube en u : hydrodynamique et transfert de matiere". Toulouse, INSA, 1987. http://www.theses.fr/1987ISAT0029.

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Etude du comportement du melange diphasique en ecoulement ascendant et descendant. Determination de la perte de charge par frottement avec et sans air, du taux de gaz global, des differents regimes d'ecoulement de la dispersion gaz liquide, du coefficient de transfert de matiere et de l'apport specifique nominal

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Hutchinson, Mark Ian. "Bulge forming of tubular components". Thesis, Sheffield Hallam University, 1988. http://shura.shu.ac.uk/19849/.

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The bulge forming process is a method for shaping tubular components using an internal hydrostatic pressure combined with a compressive axial load. Initial investigations involved carrying out an extensive literature survey to determine the components which could be formed and the effects of using lubricants and different tube materials. Die-blocks were designed to produce tee pieces, cross joints and off-set joints, and electronic on-line instrumentation was incorporated so that the forming pressures and loads could be accurately monitored. A series of tests were carried out in the forming of: (1) tee pieces, cross joints and off-set joints from copper tubes of two different wall thicknesses, (2) tee pieces using different types of plungers, (3) tee pieces using die-blocks coated with various lubricants, (4) tee pieces from aluminium, copper and steel tubes, (5) tee pieces using die-blocks with various branch radii. From the resulting components, formed with various combinations of internal pressure and compressive axial load, the limits for a successful forming operation were established. Further analysis of these components was then undertaken to evaluate the effects of the internal pressure and axial load on the bulge height and the wall thickness in the deformation zone. From these results, which have been illustrated graphically, the greatest effect on the resulting bulge can be seen to be the compressive axial load. Theoretical analyses are presented, which predict the wall thickness distribution around the bulge zone and also the axial loads required in the forming process. Comparison of these predictions with the experimental results shows fairly good agreement.

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Héraud, Pierre. "Etude de la dynamique des bulles infinies : application à l'étude de la vidange et du remplissage de réservoir". Phd thesis, Université de Provence - Aix-Marseille I, 2002. http://tel.archives-ouvertes.fr/tel-00011664.

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L'objet de cette thèse est d'étudier expérimentalement et théoriquement les régimes permanents et oscillants observés lors de la vidange et du remplissage de réservoirs. La première partie concerne l'étude de la vidange continue d'un tube par l'intermédiaire d'une bulle infinie (bulle de Dumitrescu-Taylor). L'étude expérimentale de la dynamique de ces bulles est menée en fonction de la forme de la section du tube, de la viscosité et de la tension de surface. Dans le domaine des grands nombres de Reynolds, la longueur pertinente pour l'étude de la dynamique s'avère être le périmètre mouillé tandis qu'`a faible nombre de Reynolds, c'est la surface de la section qui pilote la dynamique. La seconde partie est consacrée `a l'étude aux temps longs (régime permanent) du remplissage et de la vidange de réservoirs cylindriques. On montre expérimentalement que les bulles infinies jouent un rôle central dans les processus de vidange et de remplissage de réservoirs. Le temps court des oscillations, i.e. la période d'apparition des bulles d'air, est ensuite étudié dans les deux configurations vidange-remplissage. Dans le cas de la vidange, le rôle de la poche d'air compressible présente au fond du tube est mis en évidence ; ce phénomène s'apparente au "glouglou" de la bouteille que l'on vide. Dans le cas du remplissage, on montre la présence d'un oscillateur de nature différente.

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Proctor, Robert Neil. "Metallicities and stellar populations in spiral bulges". Thesis, University of Central Lancashire, 2002. http://clok.uclan.ac.uk/20825/.

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A major aim of current astrophysical research is the development of models of galaxy formation that are consistent with observational data. Until recently, the main tools of such research were broadband colours. However, the Lick system of indices has recently provided researchers with a more accurate tool for probing galaxy populations. The work in this thesis compares Lick indices in bright elliptical galaxies with those in the bulges of spiral galaxies, in an effort to compare, contrast and constrain their star formation histories. Long-slit spectroscopic observations of line-strengths and kinematics were carried out along the minor axes of 32 galaxies (ellipticals, SOs and spiral bulges). This study shows bulges to have central line-strengths comparable with those of single stellar populations of approximately solar metallicity or above. In bulges, central line-strengths are shown to lie close to, or within, the loci defining solar abundance ratio SSPs. The large number (24) of indices measured in this study, in conjunction with models of the effects of varying abundance ratios, permit the breaking of age/metallicity degeneracy and allow estimation of enhancements in specific light elements. Estimates of luminosity-weighted age, metallicity and abundance ratio show that, while early-type galaxies exhibit a large range of ages (2 to 13 Gyr), bulges are generally younger, and less enhanced in light elements. Trends involving age and metallicity also differ between early and late types. An anti-correlation is found between age and metallicity in early-type galaxies in the sample, while, in bulges, metallicity is correlated with velocity dispersion. Metallicity gradients are detected in all galaxies in the sample. Age gradients are also detected. No gradients are detected in abundance ratios. A "single zone with in-fall" model of galactic chemical evolution is used to constrain star formation histories of the galaxies observed. It is shown that monolithic collapse models can not reproduce the line-strengths observed in either early- or late-type galaxies. However, models including more extended star formation (e.g. mergers or secular evolution) can. The results of this work are, therefore, at odds with the received wisdom that bulges and elliptical galaxies are old and coeval, with indices in bulges more consistent with secular evolution models of formation, and those in early-type galaxies more consistent with merger models.

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Falcon, Barroso Jesus. "Kinematics & stellar populations of nearby bulges". Thesis, University of Nottingham, 2003. http://eprints.nottingham.ac.uk/10016/.

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In this thesis, we investigate the internal kinematics and stellar populations of a subsample of the bulges of nearby galaxies defined by Balcells & Peletier (1994). To do that we have analysed minor axis spectroscopic data of the sample together with Integral Field observations of one the most interesting galaxies in it (NGC7332). We introduce, for the first time, the use of single-burst stellar population models to obtain stellar velocities, velocity dispersions and higher order Gauss-Hermite moments (h_3, h_4) from galaxy spectra in the near-infrared Ca II triplet region. We detect small-amplitude minor-axis rotation, generally due to inner isophotal twists as a result of slightly triaxial bulges or misaligned inner disks. Velocity dispersion profiles, which extend well into the disk region, show a wide range of slopes. Flattened bulges tend to have shallower velocity dispersion profiles. The inferred similarity of radial velocity dispersion profiles of bulge and disk supports the interpretation of these bulges as thickened disks. We also investigate the position of our sample on the fundamental plane of early-type galaxies. We find that bulges, both in the B and K band, lie close to but slightly below the relation defined by ellipticals and S0s. The most deviant point is NGC7332, whose offset w.r.t the FP cannot be explained by measurement errors. Besides, there are hints that bulges of later morphological type are situated below the other bulges in our sample. The fact that bulges lie so close to the FP of ellipticals and S0s implies that their formation epoch must have been similar to that of cluster Es and S0s. We then proceed to present measurements of near-IR Ca triplet (CaT, CaT*), Paschen (PaT) and Magnesium (MgI) indices for the same sample. We find that CaT* decreases with central velocity dispersion (sigma) with small scatter, unlike other metal indices that generally increase. Our result shows that the CaT* - sigma relation is independent of galaxy type from ellipticals to intermediate-type spirals. Finally we have made use of SAURON observations to unravel the origin of peculiar features in the S0 galaxy NGC7332. We have discovered a Kinematically Decoupled Core, found kinematic evidence for a central disk and mapped a rather disturbed gas distribution counter-rotating w.r.t the stellar body of the galaxy. 2D stellar populations maps reveal that NGC7332 is young everywhere. The fact that we see gas inflow now, together with many features indicates that there must have been gas infall for Gyrs in a row, leading to a continuum formation of this galaxy.

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Ballero, Silvia Kuna. "Evolution of chemical abundances in active and quiescent spiral bulges". Doctoral thesis, Università degli studi di Trieste, 2008. http://hdl.handle.net/10077/2560.

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2006/2007
In this thesis I develop a chemical evolution model which takes advantage of the most recent high-quality abundance observations in the Galactic bulge to put constraints on its formation and evolution and to obtain a baseline model for bulges in general. I adopt updated massive star nucleosynthesis and follow the evolution of several alpha-elements and Fe by varying the evolutionary parameters. The [alpha/Fe] ratios in the bulge are correctly predicted to be supersolar for a wide range in [Fe/H], and the stellar metallicity distribution is reproduced assuming a short formation timescale, a high star formation efficiency and an initial mass function flatter than the disk. Metallicity-dependent oxygen yields with stellar mass loss are included in the chemical evolution models for the bulge and the solar neighbourhood. The agreement between predicted and observed [O/Mg] trends above solar metallicity is significantly improved; a normalisation problem probably indicates that the adopted semi-empirical yields need adjustment. The difference between [O/Fe] and the other [alpha/Fe] ratios in the bulge and solar neighbourhood is explained. I test the so-called universal initial mass function, suitable for ellipticals and disks, to see if the bulge stellar metallicity distribution can be reproduced by varying the yields for very massive stars, and included M31 in my analysis. I show that assuming a flatter initial mass function than the universal one is necessary, and that a variation exists in the initial mass function among different environments. Finally, I investigate the evolution of spiral bulges hosting Seyfert nuclei, with detailed calculations of the galactic potential and of the feedback from the central supermassive black hole in an Eddington-limited accretion regime. New spectro-photometrical evolution codes covering a wide range of stellar ages and metallicities allowed to model the photometric features of local bulges. I successfully predict the observed black hole-host bulge mass relation. The observed present-day nuclear bolometric luminosity is achieved only for the most massive bulges, otherwise a rejuvenation is necessary. The observed high star formation rates and metallicities, constancy of chemical abundances with the redshift and bulge present-day colours are reproduced, but a steeper initial mass function is required to match the colour-magnitude relation and the present K-band bulge luminosity.
In questa tesi, ho sviluppato un modello di evoluzione chimica che si avvale di recenti osservazioni ad alta qualità di abbondanze chimiche nel bulbo della Via Lattea, per porre dei vincoli sui suoi meccanismi di formazione ed evoluzione e ottenere un modello generale per i bulbi di spirale. Ho adottato una nucleosintesi aggiornata per le stelle massicce e seguito l'evoluzione di diversi elementi-alpha e del ferro, variando i parametri evolutivi. Si prevede correttamente che i rapporti [alpha/Fe] nel bulbo siano soprasolari per un ampio intervallo in [Fe/H]. La distribuzione in metallicità è riprodotta con un tempo di formazione breve, un'alta efficienza di formazione stellare e una funzione iniziale di massa più piatta che nel disco. Yields di ossigeno con perdita di massa stellare in funzione della metallicità sono stati inclusi nei modelli di evoluzione chimica del bulbo e dei dintorni solari. L'accordo tra gli andamenti di [O/Mg] previsti e osservati per metallicità soprasolari risulta sensibilmente migliorato; si spiega inoltre la differenza tra il rapporto [O/Fe] e gli altri [alpha/Fe] nel bulbo e nei dintorni solari. Un problema di normalizzazione indica che probabilmente gli yields semi-empirici adottati necessitano una revisione. Ho verificato se con la cosiddetta funzione iniziale di massa universale, adeguata per galassie ellittiche e dischi, la distribuzione in metallicità stellare del bulge può essere riprodotta calibrando gli yields delle stelle supermassicce, includendo M31 nell'analisi. Si dimostra che una funzione iniziale di massa più piatta di quella universale è necessaria, e che esiste una variazione nella funzione iniziale di massa tra i diversi ambienti. Infine, ho studiato l'evoluzione di bulbi di spirali che ospitano galassie di Seyfert, mediante calcoli dettagliati del potenziale galattico e del feedback dal buco nero supermassiccio centrale in un regime di accrescimento limitato dal tasso di Eddington. Nuovi codici spettro-fotometrici che coprono un ampio intervallo di età stellari e di metallicità hanno permesso di modellizzare le caratteristiche fotometriche dei bulbi locali. La relazione osservata tra massa del buco nero e del bulbo ospite è prevista con successo. La luminosità bolometrica nucleare misurata al tempo presente si consegue solo per i bulbi più massicci, negli altri casi è necessario un "ringiovanimento". Le osservazioni di alto tasso di formazione stellare, alte metallicità, invarianza di abbondanze chimiche col redshift e colori dei bulbi locali sono riprodotte; una funzione iniziale di massa più ripida è invece richiesta per la relazione colore-magnitudo e la luminosità dei bulbi in banda K al tempo presente.
XX Ciclo
1979

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Libri sul tema "Bulges on the tube"

Gallery, Southern Alberta Art. Panya Clark: Like ancient pots spilled from a drowned ship, tube sponges bulge eerily ... Alberta: Southern Alberta Art Gallery, 1994.

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Laurikainen, Eija, Reynier Peletier e Dimitri Gadotti, a cura di. Galactic Bulges. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-19378-6.

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Dejonghe, Herwig, e Harm J. Habing, a cura di. Galactic Bulges. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-0922-2.

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James, Hart, O'Toole Mitch e O'Toole Gjyn, a cura di. Time tube. Clayton South, Vic: Blake Education, 2005.

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Dunitz-Scheer, Marguerite, e Peter J. Scheer. Child-led Tube-management and Tube-weaning. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-09090-5.

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Moyer, R. G. Reduction of pressure-tube/calandria-tube contact conductance. Pinawa, Man: Whiteshell Laboratories, 1992.

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Lazareff, Jorge A. Neural tube defects. Singapore: World Scientific Pub. Co., 2011.

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Archiv, Max Beckmann. Minna Beckmann-Tube. München: Bayerische Staatsgemäldesammlungen, Max Beckmann Archiv, 1998.

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Clermont, Jean-Robert, e Amine Ammar. Stream-Tube Method. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-65470-2.

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Malhó, Rui, a cura di. The Pollen Tube. Berlin/Heidelberg: Springer-Verlag, 2006. http://dx.doi.org/10.1007/11493198.

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Capitoli di libri sul tema "Bulges on the tube"

King, Ivan R. "Review of the Galactic Bulge". In Galactic Bulges, 3–20. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-0922-2_1.

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Renzini, Alvio. "Formation and Evolution of Stars in Galactic Bulges". In Galactic Bulges, 151–68. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-0922-2_10.

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Rich, R. Michael. "The Stellar Population of the Inner 200 Parsecs". In Galactic Bulges, 169–90. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-0922-2_11.

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de Zeeuw, Tim. "Dynamics of the Galactic Bulge". In Galactic Bulges, 191–208. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-0922-2_12.

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Kormendy, John. "Kinematics of Extragalactic Bulges: Evidence that some Bulges are Really Disks". In Galactic Bulges, 209–30. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-0922-2_13.

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Bertola, Francesco. "Photometric Properties of Extragalactic Bulges". In Galactic Bulges, 231–42. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-0922-2_14.

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Franx, Marijn. "What is the Connection between Ellipticals and Bulges ?" In Galactic Bulges, 243–62. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-0922-2_15.

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Freeman, K. C. "Summary: Achievements and Open Questions". In Galactic Bulges, 263–70. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-0922-2_16.

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Friedli, D., e S. Udry. "3D Gas Dynamics in Triaxial Systems". In Galactic Bulges, 273–74. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-0922-2_17.

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Gerhard, Ortwin E., e James Binney. "Dynamics of the Galactic Bulge from Gas Motions". In Galactic Bulges, 275–82. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-0922-2_18.

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Atti di convegni sul tema "Bulges on the tube"

French, Stephen, e Carl Skelonis. "Creep Failure of a Chromized Waterwall Tube in a Supercritical Boiler". In ASME 2005 Pressure Vessels and Piping Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/pvp2005-71018.

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In Spring, 2000, as part of a continuous mitigation program for circumferential cracking and waterwall wastage, 88 tubes, in panel sections of 22 tubes, were installed into the centerwall of a supercritical boiler. The replacement tubes were low alloy (1-1/4Cr-1/2Mo) steel chromized to a nominal depth of 12–20 mils (0.3–0.5 mm). After only three years of operation, one tube failed due to creep. Four months later, a second creep failure occurred in the same centerwall panel and four other tubes were removed due to visual variations in dimension. Two months later, two more tubes were removed with bulges. Two months following that, during the scheduled overhaul, seven other tubes were removed due to the formation of bulges and extensive creep damage was found in three of the four panels comprising the chromized tube section. Metallurgical evidence indicates tube metal temperatures in excess of 1000°F. Creep testing was performed on samples taken from this unit and its identical sister unit. The first data shows the creep properties to fall near the minimum band for this Cr-Mo alloy, but the testing remains ongoing.

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Himeno, M., S. Noda, R. Himeno e K. Fukasaku. "Application of Genetic Algorithm to Prediction of Artery Geometry". In ASME/JSME 2007 5th Joint Fluids Engineering Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/fedsm2007-37241.

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We used the genetic algorithm (GA) and two-dimensional blood flow analysis to examine the fluid dynamic and engineering factors in multi-objective optimization of blood tubes (vessels). We supposed two factors from fluid dynamics: the wall shear stress (WSS) and the pressure loss, and one materials saving factor: the artery length. As a result, we could get the optimum shapes for each factor. In the case of WSS and artery length, both smoothly curved artery shapes and shapes with bulges were obtained as lower WSS cases. The shapes with bulges were similar to those of aneurysms. In this case, it was found that the WSS increases after the bulge is removed. This means bulges in artery vessel areas with higher WSSs effectively reduce the WSS value. Only the case of WSS and artery length produced a shape like an aneurysm. These results indicate that WSS and artery length are significant factors in determining artery shape.

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Memon, Shabbir, Obaidur Rahman Mohammed e Hamid M. Lankarani. "Effect of Pre-Bending on Formability of DQ Steel and Al 5182". In ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-87321.

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The effect of the pre-bending operation on ductility can be significant in determining the limit strains of the final product. The strain path experienced in straight tube bulging is significantly different from that of elbow (tube with pre-bending), leading to a reduction in bulge height. The Tube bending introduces strain gradient both along the tube and across the tube. In this work the effect of pre-bending on limit strains during tube bulging process is predicted — and the results are compared to the limit strains of bulged tubes without pre-bending. The Finite Element (FE) model of the bending operation is developed which utilizes an explicit dynamic finite element formulation. The PAMSTAMP 2G code is used to perform the numerical pre-bend (and bulging) simulations. Tension side of bend tube axial strain is found to be positive and hoop strain as negative and vice versa along the compression side. During the bulging, the neck usually develops perpendicular to major strain direction. During bend tube bulge test with fixed expansion and axial feed expansion of bend tubes, in both cases the crack is found to be in the axial direction.

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BECHLER, Jan. "Influence of the forming pre-strain on the fatigue performance of upset bulge formed tubes". In Material Forming. Materials Research Forum LLC, 2024. http://dx.doi.org/10.21741/9781644903131-106.

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Abstract. Safety-relevant components in the automotive industry must fulfill stringent requirements for performance, particularly in endurance. The height adjustment system in a car seat is one example. The height adjustment system is made up of sheet metal parts which are joined with steel tubes through axial compression – also referred to as upset bulge forming. As a result of the forming process, initial cracks occur at the inner bending radius of the tubes which, along with the forming history, decrease the fatigue life by 450%. The aim of this study is to identify whether the initial cracks occur due to shear bending generated by the process or elastic springback. The influence of the elastic springback on the crack initiation is investigated through bending experiments of DP600, Al99.5, and 1.4301. To prevent elastic springback, the specimens are secured with screws post-bending and are removed afterwards. The bending radius is investigated with respect to the equivalent plastic strain to determine a minimum without failure. Cyclic tests of bulges with two different forming histories are tested to investigate the influence of the forming pre-strain on the fatigue behavior. In all bent materials, initial cracks occur at the inner bending radius where the elastic springback increases the initial cracks and Scanning Electron Microscopy (SEM) analysis confirms shearing as the cause. It was also found the grain shape and orientation have a significant influence on the crack propagation in the forming zone of the tube through the upset bulging process.

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Memon, Shabbir, e Chetan P. Nikhare. "A Numerical Analysis on Taper Tube Hydroforging". In ASME 2022 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/imece2022-95536.

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Abstract Typically, in tube forming, the end cross section is either expanded or reduced, or the tube is bent around a solid mandrel to achieve the desired shape. To reduce the friction generated between the tube and the physical tool like mandrel the tube hydroforming process was developed. The fluid was highly pressurized to expand the tube to a desired shape. The uniform thickness and thus better formability are achieved by replacing mandrel punch with hydraulic pressure in tube hydroforming. If the axial force to deform the tube is dominant in deforming the tube, then the process is termed as hydroforging. In this paper a two-step hydroforging process is discussed. With this two-step process, firstly the tube is bulged using the low fluid pressure and then axial force was applied to deform the tube axially and circumferentially while a constant internal fluid pressure was applied to prevent the buckling. During the first step a ramp pressure is used to provide a maximum bulging without necking, then in the next step a constant same peak ramp pressure or lower is applied while compressing the tube axially. In the previous study, a straight tube was used to study the pressure requirement, bulging, buckling and deformation mechanics to create a disc shape object. In this paper, a taper tube hydroforging was studied. The same two-step process was applied to bulge the tube first and then axially deform the tube. Two tube thicknesses and three angles were studied. The pressure requirement to bulge the tube and deform the tube was investigated. The deformation mechanics was analyzed. In addition, the stress, strain, and thickness distribution were studied and reported.

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Chen, Kuo-Kuang. "The Bulge of Tubes and a Failure Criterion for Tube Hydroforming". In SAE 2001 World Congress. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2001. http://dx.doi.org/10.4271/2001-01-1132.

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van Zyl, Gys, e Sultan Al-Harthi. "Fitness for Service Assessment and Repair of the Liner of a High Pressure Heat Exchanger". In ASME 2018 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/pvp2018-85001.

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A high pressure carbamate condenser (HPCC) is a shell and tube heat exchanger with low pressure steam/condensate on the shell side and high pressure carbamate solution on the tube side. The inlet channel of the exchanger is protected from the internal corrosive environment by means of an austenitic stainless steel liner. During the first internal inspection after commissioning, a bulge was observed in the liner where a pass partition plate is joined to the liner. Surface-breaking cracks were observed at the partition plate to liner welds in the bulged region. The cracks were removed by shallow grinding, but a fitness-for-service assessment was required to evaluate the suitability of the bulged liner for continued service. Due to the complexity of the geometry, a handheld 3D geometry scanner was used to accurately measure the deformed shape of the bulge. Using the measured geometry, a finite element model was developed and used to perform a level 3 fitness for service assessment. This paper will describe the assessment procedure in detail as well as the complex internal repairs that were ultimately implemented in order to restore the integrity of the equipment.

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D’Urso, G., M. Longo e C. Giardini. "Characterization of Friction Stir Welded Tubes by Means of Tube Bulge Test". In THE 14TH INTERNATIONAL ESAFORM CONFERENCE ON MATERIAL FORMING: ESAFORM 2011. AIP, 2011. http://dx.doi.org/10.1063/1.3589689.

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Mendes, A. C., L. M. A. Paredes, F. A. S. Gil e J. R. Chaplin. "Small-Scale Model Tests of a Rubber-Tube Wave Energy Converter With Pneumatic Power Take-Off". In ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/omae2014-23452.

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The paper deals with a relatively new concept in wave-energy conversion systems: the Anaconda. This device consists basically of a distensible tube, made out of rubber material, which interacts with the incident waves in order to convey the absorbed energy to some form of power take-off (PTO). In the present case, the bulges inside the rubber tube drive a slug of water towards a vertical shaft referred to as a chimney. The oscillations of the water column inside the chimney induce a pressure oscillation in the pneumatic chamber above that activates an air-turbine. The Anaconda device has been studied extensively by experimental and theoretical means. However, so far, the pneumatic PTO for this device has only been examined within restrictive linear conditions. This study is about a series of 1:100 scale model tests of a freely floating Anaconda in a wave flume, under deep and intermediate water regular waves, for a device equipped with a non-linear PTO. In the model, the pneumatic chamber communicates with the atmosphere through an orifice. Three calibrated orifices of different diameters have been tested. The pressure across the orifice is determined from measurements taken of the amplitude of water column oscillations in the system, by applying Bernoulli’s law. These properties are subsequently used for calculating the power captured from the incident waves. Estimates of power output and energy capture width are presented, as functions of wave frequency, while the device interacts with linear and second-order waves. Our estimates are finally extrapolated to predict prototype performance.

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Zheng, Boren, Kunrong Shen, Wei Li, Xiang Ma, Chuancai Zhang, Yan He, Hanbing Ke e Yuansheng Lin. "Condensation Characteristics of Flows Inside the Three-Dimensional Enhanced Tubes". In ASME 2020 18th International Conference on Nanochannels, Microchannels, and Minichannels collocated with the ASME 2020 Heat Transfer Summer Conference and the ASME 2020 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/icnmm2020-1052.

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Abstract This paper presents experimental condensation characteristics of R134a inside two three-dimensional enhanced heat transfer tubes (1EHT1 and 3EHT) and one equivalent smooth tube. The 1EHT1 tube has the primary elliptical dimples and secondary petal arrays, and the 3EHT tube has the grooves and square bulge. All the tested stainless-steel tubes have the same outer diameter of 15.88 mm. The test tubes are installed in a horizontal test section with an effective length of 2 m. In these experiments, condensation temperature is kept constant at 318K. The refrigerant qualities at the test section inlet and outlet are 0.8 and 0.2. Mass flux is varied from 70 kg/(m2s) to 170 kg/(m2s). In a comparison of condensation heat transfer performance, the 1EHT1 tube has the best heat performance followed by the 3EHT tube. Condensing coefficients of the 1EHT1 tube and the 3EHT tube are about 1.45 times and 1.16 times that of the smooth tube, respectively. The experimental results in this study are compared with other experiments conducted by R410A under similar experimental conditions to evaluate the thermal performance.

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Rapporti di organizzazioni sul tema "Bulges on the tube"

Grossmann, Rafael J. Chest Tube Insertion. Touch Surgery Simulations, marzo 2015. http://dx.doi.org/10.18556/touchsurgery/2015.s0041.

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Kurita, C. H. EC Tube Fits. Office of Scientific and Technical Information (OSTI), marzo 1987. http://dx.doi.org/10.2172/1030739.

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Swift, G., e D. Gardner. Downhole pulse tube refrigerators. Office of Scientific and Technical Information (OSTI), dicembre 1997. http://dx.doi.org/10.2172/555366.

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Beaux II, Miles Frank, e Igor Olegovich Usov. Molybdenum Tube Characterization report. Office of Scientific and Technical Information (OSTI), febbraio 2017. http://dx.doi.org/10.2172/1342881.

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Faltens, A. Pulsed Drift Tube Accelerator. Office of Scientific and Technical Information (OSTI), ottobre 2004. http://dx.doi.org/10.2172/861362.

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MacDonald, P. E., V. N. Shah, L. W. Ward e P. G. Ellison. Steam generator tube failures. Office of Scientific and Technical Information (OSTI), aprile 1996. http://dx.doi.org/10.2172/236258.

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Reichenbach, H., e G. Scheklinski-Gluck. EMI Shock Tube Experiments. Fort Belvoir, VA: Defense Technical Information Center, luglio 1991. http://dx.doi.org/10.21236/ada239055.

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Rossi, D., M. Widgoff e E. Alyea. Streamer tube readout electronics. Office of Scientific and Technical Information (OSTI), marzo 1989. http://dx.doi.org/10.2172/7018875.

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Mulcahy, T. M. Leakage flow-induced vibration of an eccentric tube-in-tube slip joint. Office of Scientific and Technical Information (OSTI), agosto 1985. http://dx.doi.org/10.2172/5043218.

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Mulcahy, T. M. Leakage flow-induced vibrations for variations of a tube-in-tube slip joint. Office of Scientific and Technical Information (OSTI), gennaio 1986. http://dx.doi.org/10.2172/5764500.

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