Academic literature on the topic 'Number of bundles'
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Journal articles on the topic "Number of bundles"
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Abadie, Fernando, and Damian Ferraro. "Equivalence of Fell bundles over groups." Journal of Operator Theory 81, no. 2 (2019): 273–319. http://dx.doi.org/10.7900/jot.2018feb02.2211.
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We give a notion of equivalence for Fell bundles over groups, not necessarily saturated nor separable. The equivalence between two Fell bundles is implemented by a bundle of Hilbert bimodules with some extra structure. Suitable cross-sectional spaces of such a bundle turn out to be imprimitivity bimodules for the cross-sectional C∗-algebras of the involved Fell bundles. We show that amenability is preserved under this equivalence.
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Mozgovoy, Sergey, and Olivier Schiffmann. "Counting Higgs bundles and type quiver bundles." Compositio Mathematica 156, no. 4 (2020): 744–69. http://dx.doi.org/10.1112/s0010437x20007010.
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We prove a closed formula counting semistable twisted (or meromorphic) Higgs bundles of fixed rank and degree over a smooth projective curve of genus $g$ defined over a finite field, when the twisting line bundle degree is at least $2g-2$ (this includes the case of usual Higgs bundles). This yields a closed expression for the Donaldson–Thomas invariants of the moduli spaces of twisted Higgs bundles. We similarly deal with twisted quiver sheaves of type $A$ (finite or affine), obtaining in particular a Harder–Narasimhan-type formula counting semistable $U(p,q)$-Higgs bundles over a smooth projective curve defined over a finite field.
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Tilney, Lewis G., Patricia S. Connelly, Linda Ruggiero, Kelly A. Vranich, and Gregory M. Guild. "Actin Filament Turnover Regulated by Cross-linking Accounts for the Size, Shape, Location, and Number of Actin Bundles in Drosophila Bristles." Molecular Biology of the Cell 14, no. 10 (2003): 3953–66. http://dx.doi.org/10.1091/mbc.e03-03-0158.
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Drosophila bristle cells are shaped during growth by longitudinal bundles of cross-linked actin filaments attached to the plasma membrane. We used confocal and electron microscopy to examine actin bundle structure and found that during bristle elongation, snarls of uncross-linked actin filaments and small internal bundles also form in the shaft cytoplasm only to disappear within 4 min. Thus, formation and later removal of actin filaments are prominent features of growing bristles. These transient snarls and internal bundles can be stabilized by culturing elongating bristles with jasplakinolide, a membrane-permeant inhibitor of actin filament depolymerization, resulting in enormous numbers of internal bundles and uncross-linked filaments. Examination of bundle disassembly in mutant bristles shows that plasma membrane association and cross-bridging adjacent actin filaments together inhibits depolymerization. Thus, highly cross-bridged and membrane-bound actin filaments turn over slowly and persist, whereas poorly cross-linked filaments turnover more rapidly. We argue that the selection of stable bundles relative to poorly cross-bridged filaments can account for the size, shape, number, and location of the longitudinal actin bundles in bristles. As a result, filament turnover plays an important role in regulating cytoskeleton assembly and consequently cell shape.
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Sima, SN, AK Roy, and N. Joarder. "Erect culm internodal anatomy and properties of sun ecotype of Imperata cylindrica (L.) P. Beauv." Bangladesh Journal of Botany 44, no. 1 (2015): 67–72. http://dx.doi.org/10.3329/bjb.v44i1.22725.
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Internodal anatomy of Imperata cylindrica (L.) P. Beauv. was described in this paper. Culm internodes were completely encircled by leaf sheath. Peripheral vascular bundles were many in number and small in size. Central bundles were large in size and a few in number. Large bundles were of various sizes and vascular tissues well developed. Each vascular bundle had strong mass of sclerenchyma tissue arching over the phloem in the form of phloem hood. Small bundles were poorly developed in respect of vascular tissue. A small percentage of vascular bundle consisted of phloem tissue only fundamental ground tissues were parenchyma in nature. DOI: http://dx.doi.org/10.3329/bjb.v44i1.22725 Bangladesh J. Bot. 44(1): 67-72, 2015 (March)
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Winnie, Kathrine Anne, Kimberly Sanchez, Elizabeth Winfrey, et al. "Practice Integration as an Effective Educational Strategy." AACN Advanced Critical Care 33, no. 4 (2022): 319–28. http://dx.doi.org/10.4037/aacnacc2022171.
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Bundles are composed of individually established practices supported by research that, when combined, structure patient care. Implementing bundles improves patient outcomes. The ABCDEF initiative is an example of a bundled approach that improves outcomes of critically ill patients that are related to the likelihood of hospital death within 7 days, delirium and coma days, physical restraint use, intensive care unit readmission, and discharge disposition, with outcomes being proportional to the number of appropriate components performed. The purpose of this quality improvement project was to implement practice integration as an educational strategy to increase nursing knowledge of complex topics and, specifically, components of the ABCDEF bundle. Nurses’ knowledge of all the BDE components of the ABCDEF bundle increased after implementing practice integration. Findings from this project support the use of resources to implement practice integration as an educational strategy for comprehensive concepts, specifically the BDE components of the ABCDEF bundle.
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Harker, Alyssa J., Harshwardhan H. Katkar, Tamara C. Bidone, et al. "Ena/VASP processive elongation is modulated by avidity on actin filaments bundled by the filopodia cross-linker fascin." Molecular Biology of the Cell 30, no. 7 (2019): 851–62. http://dx.doi.org/10.1091/mbc.e18-08-0500.
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Ena/VASP tetramers are processive actin elongation factors that localize to diverse F-actin networks composed of filaments bundled by different cross-linking proteins, such as filopodia (fascin), lamellipodia (fimbrin), and stress fibers (α-actinin). Previously, we found that Ena takes approximately threefold longer processive runs on trailing barbed ends of fascin-bundled F-actin. Here, we used single-molecule TIRFM (total internal reflection fluorescence microscopy) and developed a kinetic model to further dissect Ena/VASP’s processive mechanism on bundled filaments. We discovered that Ena’s enhanced processivity on trailing barbed ends is specific to fascin bundles, with no enhancement on fimbrin or α-actinin bundles. Notably, Ena/VASP’s processive run length increases with the number of both fascin-bundled filaments and Ena “arms,” revealing avidity facilitates enhanced processivity. Consistently, Ena tetramers form more filopodia than mutant dimer and trimers in Drosophila culture cells. Moreover, enhanced processivity on trailing barbed ends of fascin-bundled filaments is an evolutionarily conserved property of Ena/VASP homologues, including human VASP and Caenorhabditis elegans UNC-34. These results demonstrate that Ena tetramers are tailored for enhanced processivity on fascin bundles and that avidity of multiple arms associating with multiple filaments is critical for this process. Furthermore, we discovered a novel regulatory process whereby bundle size and bundling protein specificity control activities of a processive assembly factor.
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Williamson, R. E., and U. A. Hurley. "Growth and regrowth of actin bundles in Chara: bundle assembly by mechanisms differing in sensitivity to cytochalasin." Journal of Cell Science 85, no. 1 (1986): 21–32. http://dx.doi.org/10.1242/jcs.85.1.21.
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Cytochalasin is known to inhibit cytoplasmic streaming rapidly in characean cells without disassembling their actin bundles. Lower cytochalasin concentrations than those needed for streaming inhibition are now shown to disrupt bundle assembly and, over longer periods, assembled bundles. After local wounding, cytochalasin limited bundle regeneration to the production of polygons and straight, discontinuous bundles that rarely connected to bundles outside the wound. The regenerated bundles supported only scattered organelle movements, whereas long, oriented bundles of control cells were connected to those outside the wound and supported bulk endoplasmic streaming. Unwounded Chara plants cultured for up to 2 weeks in 1 microM-cytochalasin maintained normal bundle orientation and rapid cytoplasmic streaming, but the mean number of bundles per file of chloroplasts fell from 5.2 in controls to 2.0 in growing cells and 3.4 in nongrowing cells. These structural effects seem more likely than the streaming inhibition to reflect cytochalasin's in vitro effect of blocking extension at the barbed but not the pointed end of F-actin. In particular, cytochalasin inhibited the extension into the wound of bundles in which only the barbed ends of filaments would be exposed. However, short lengths of isolated bundles grew within the wound and bundle growth in the intact cell continued, albeit in modified form. It is suggested that these examples of continuing bundle growth involve cytochalasin-resistant mechanisms that are not wholly dependent on barbed-end filament growth.
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Biquard, Olivier, Brian Collier, Oscar García-Prada, and Domingo Toledo. "Arakelov–Milnor inequalities and maximal variations of Hodge structure." Compositio Mathematica 159, no. 5 (2023): 1005–41. http://dx.doi.org/10.1112/s0010437x23007157.
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In this paper we study the $\mathbb {C}^*$ -fixed points in moduli spaces of Higgs bundles over a compact Riemann surface for a complex semisimple Lie group and its real forms. These fixed points are called Hodge bundles and correspond to complex variations of Hodge structure. We introduce a topological invariant for Hodge bundles that generalizes the Toledo invariant appearing for Hermitian Lie groups. An important result of this paper is a bound on this invariant which generalizes the Milnor–Wood inequality for a Hodge bundle in the Hermitian case, and is analogous to the Arakelov inequalities of classical variations of Hodge structure. When the generalized Toledo invariant is maximal, we establish rigidity results for the associated variations of Hodge structure which generalize known rigidity results for maximal Higgs bundles and their associated maximal representations in the Hermitian case.
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Nitin, P. Meshram* and Kishor S. Janbandhu. "HISTOLOGICAL STUDIES OF INTERSTITIAL CELLS IN THE OVARIES OF BATS MEGADERMA LYRA LYRA AND ROUSETTUS LESCHENAULTI." Indian Journal of Medical Research and Pharmaceutical Sciences 4, no. 2 (2017): 25–35. https://doi.org/10.5281/zenodo.293796.
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Bats are the most diverse and successful group of mammals exhibiting many adaptive specializations.Chiroptera shows great variations in the reproductive stage, even the closely allied species exhibit different breeding habits. It is important to study the reproductive organ that is ovary in respect with the interstitial cells, because the interstitial cells with the help of LH of pituitary produce a hormone androgen. That means interstitial tissues are developed as a gland having steroidogenic activity. The immature ovary of Megaderma lyra lyra showed the small bundles of few interstitial cells in stromal region. In inactive ovary of Megaderma lyra lyra, interstitial cell bundles observed 48 ± 5 and number of interstitial cells observed in each bundle are 5 to 9. In the active ovary of Megaderma lyra lyra the bundles of interstitial cells observed 56 ± 5. Number of interstitial cells in each bundle in Megaderma lyra lyra observed 10 to 20. Pregnant ovary of Megaderma lyra lyra showed extroverted carpus luteum, atretic follicles and destructed interstitial cells. In the immature ovary of Rousettus leschenaulti numerous interstitial cells observed in the stromal region. In the inactive ovary of Rousettus leschenaulti, interstitial cell bundles observed 41 ± 5 and number of interstitial cells observed in each bundle are 5 to 7. In active ovary of Rousettus leschenaulti the bundles of interstitial cells observed 47 ± 5. And number of interstitial cells observed in each bundle are 5 to 10, So it is concluded that the interstitial cells in the active ovary is more steroidogenic than inactive ovary
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Sathyakam, P. Uma, P. S. Mallick, and Paridhi Singh. "Geometry-Based Crosstalk Reduction in CNT Interconnects." Journal of Circuits, Systems and Computers 29, no. 06 (2019): 2050094. http://dx.doi.org/10.1142/s0218126620500942.
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This paper proposes novel triangular cross-sectioned geometry of carbon nanotube (CNT) bundles for crosstalk and delay reduction in CNT bundle interconnects for VLSI circuits. First, we formulate the equivalent single conductor (ESC) transmission line models of the interconnects. Through SPICE analysis of the ESC circuits, we find the propagation delays of the proposed CNT bundles. Next, we model the capacitively coupled interconnects for crosstalk analysis. It is found that the coupling capacitance of triangular CNT bundle is 29% lesser than the traditionally used square CNT bundles. Further, the crosstalk-induced delay of triangular interconnects is found to be 30% lesser when compared to square bundle interconnects. The reduction in delay is found to increase as the number of CNTs in the bundle increases. So, we suggest that triangular CNT bundles are the most suitable candidates as global interconnects.
Dissertations / Theses on the topic "Number of bundles"
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Wakabayashi, Yasuhiro. "An explicit formula for the generic number of dormant indigenous bundles." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188460.
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Gounelas, Frank. "Free curves on varieties." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:3a7f6dba-fad2-4517-994e-0b51ea311df8.
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In this thesis we study various ways in which every two general points on a variety can be connected by curves of a fixed genus, thus mimicking the notion of a rationally connected variety but for arbitrary genus. We assume the existence of a covering family of curves which dominates the product of a variety with itself either by allowing the curves in the family to vary in moduli, or by assuming the family is trivial for some fixed curve of genus g. A suitably free curve will be one with a large unobstructed deformation space, the images of whose deformations can join any number of points on a variety. We prove that, at least in characteristic zero, the existence of such a free curve of higher genus is equivalent to the variety being rationally connected. If one restricts to the case of genus one, similar results can be obtained even allowing the curves in the family to vary in moduli. In later chapters we study algebraic properties of such varieties and discuss attempts to prove the same rational connectedness result in positive characteristic.
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Kindfuller, Vincent John. "Improvements to the Cheng-Todreas wire-wrapped rod bundle friction factor correlation in response to pin number and in the transition flow region." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/106697.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2016.<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>Cataloged from student-submitted PDF version of thesis.<br>Includes bibliographical references (pages 51-52).<br>The Cheng-Todreas Detailed (CTD) Pressure Drop Correlation (1986) is the most accurate correlation for measuring the pressure drop of sodium coolant through a Sodium-Cooled Fast Reactor (SFR). Although CTD is the most accurate correlation, there is room for improvement with new data and modern ways to visualize data and check the accuracy of changes easily. This thesis attempts to offer a method for altering the CTD correlation to better account for changing pin numbers in SFR assemblies, and a better fit for the correlation to the data in the transition flow region between turbulent and laminar flow. Although CTD is more accurate than other correlations, it shows an inverse response to changing pin number in some geometries of bundle assemblies. In this thesis, a method is laid out to attempt to correct for that inverse response. Although no successful conclusion was reached, the thesis also offers a method for future attempts at improvement. In addition, a set of Matlab codes are offered that allow changes to be easily attempted and checked for validity. In addition, examining the data points of bundles in the transition flow regime shows possibilities for improving the accuracy of the correlation in that flow region. Two changes are implemented in this thesis: a change to the equation for the boundary between laminar and transition flow, and a change to the transition region friction factor equation. Both changes, when implemented, offer slight improvements to the overall accuracy and precision of the Cheng-Todreas Pressure Drop Correlation..<br>by Vincent John Kindfuller.<br>S.B.
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Neto, Aurelio Menegon. "Números de Milnor e obstrução de Euler." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/55/55135/tde-14092007-101056/.
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Neste trabalho, definimos a obstrução local de Euler de um espaço analítico complexo singular (X, \'x IND.0\'), denotada por Eu(X, \'x IND.0\'), e a obstrução local de Euler de uma função holomorfa f definida neste espaço, com uma singularidade isolada em \'x IND. 0\', denotada por \'Eu IND. f\' (X, \'x IND.0\'); e apresentamos duas fórmulas para seus respectivos cálculos. Em seguida, através de uma abordagem geométrica, determinamos as relações entre \'Eu IND. f\' (X,\'x IND.0\') e algumas generalizações do número de Milnor para funções em espaços singulares<br>In this work we define the local Euler obstruction of a complex analytic singularity (X, \'x IND.0\'), denoted Eu(X, \'x IND.0\'), and the local Euler obstruction of a holomorphic function f defined on this space, with an isolated singularity at \'x IND. 0\', denoted \'Eu IND. f\' (X, \'x IND.0\'); and we present two formulas for their respective calculations. Next, using a geometric approach, we determine the relations between \'Eu IND.f\' (X, \'x IND.0\') and several generalizations of the Milnor number for functions on singular spaces
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Chen, Zhangchi. "Differential invariants of parabolic surfaces and of CR hypersurfaces; Directed harmonic currents near non-hyperbolic linearized singularities; Hartogs’ type extension of holomorphic line bundles; (Non-)invertible circulant matrices On differential invariants of parabolic surfaces A counterexample to Hartogs’ type extension of holomorphic line bundles Directed harmonic currents near non-hyperbolic linearized singularities Affine Homogeneous Surfaces with Hessian rank 2 and Algebras of Differential Invariants On nonsingularity of circulant matrices." Thesis, université Paris-Saclay, 2021. http://www.theses.fr/2021UPASM005.
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La thèse se compose de 6 articles. (1) Nous calculons les générateurs des SA₃(ℝ)-invariants pour les surfaces paraboliques. (2) Nous calculons les invariants rigides relatifs pour les hypersurfaces rigides 2-non-dégénérées de rang de Levi constant 1 dans ℂ³: V₀, I₀, Q₀ ayant 11, 52, 824 monômes au numérateur. (3) Nous organisons tous les modèles affinement homogènes non-dégénérés dans ℂ³ en branches inéquivalentes. (4) Pour un courant harmonique dirigé autour d'une singularité linéarisée non-hyperbolique qui ne charge pas les séparatrices triviales dont l'extension triviale à travers 0 est ddc-fermée, nous démontrons que le nombre de Lelong en 0 est : 4.1) strictement positif si λ>0 ; 4.2) nul si λ est rationnel et négatif ; 4.3) nul si λ est négatif et si T est invariant sous l'action d'un sous-groupe cofini du groupe de monodromie. (5) Nous construisons des fibrés holomorphes en droites en toute dimension n>=2 non-prolongeables au sens de Hartogs. (6) Nous montrons que les matrices circulantes ayant k entrées 1 et k+1 entrées 0 dans leur première rangée sont toujours non singulières lorsque 2k+1 est soit une puissance d'un nombre premier, soit un produit de deux nombres premiers distincts. Pour tout autre entier 2k+1, nous exhibons une matrice circulante singulière<br>The thesis consists of 6 papers. (1) We calculate the generators of SA₃(ℝ)-invariants for parabolic surfaces. (2) We calculate rigid relative invariants for rigid constant Levi-rank 1 and 2-non-degenerate hypersurfaces in ℂ³: V₀, I₀, Q₀ having 11, 52, 824 monomials in their numerators. (3) We organize all affinely homogeneous nondegenerate surfaces in ℂ³ in inequivalent branches. (4) For a directed harmonic current near a non-hyperbolic linearized singularity which does not give mass to any of the trivial separatrices and whose trivial extension across 0 is ddc-closed, we show that the Lelong number at 0 is: 4.1) strictly positive if the eigenvalue λ>0; 4.2) zero if λ is a negative rational number; 4.3) zero if λ<0 and if T is invariant under the action of some cofinite subgroup of the monodromy group. (5) We construct non-extendable, in the sense of Hartogs, holomorphic line bundles in any dimension n>=2. (6) We show that circulant matrices having k ones and k+1 zeros in the first row are always nonsingular when 2k+1 is either a power of a prime, or a product of two distinct primes. For any other integer 2k+1 we exhibit a singular circulant matrix
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Hössjer, Emil. "Generalized Abelian Gauge Theory & Generalized Global Symmetry." Thesis, Uppsala universitet, Teoretisk fysik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-434474.
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We study Cheeger-Simons differential characters in order to define higher form U(1) gauge fields and their Wilson lines. We then go on to define generalized global symmetries. This is a topological formulation of symmetries which has interesting consequences when the charged operators extend through space. Our main source of such charged operators are the generalized Wilson lines. A higher form Noether theorem and a Ward identity are given for transformations of Wilson lines. As examples of quantum field theories with generalized symmetries we cover Sigma models, Maxwell theory and BF-theory. These are examples of Z, U(1) and Zn symmetries respectively. Finally we discuss spontaneous symmetry breaking for higher dimensional symmetries and a Goldstone theorem is provided. These massless Goldstone bosons are shown to have internal structure corresponding to non-zero spin. The photon is identified as the spin one Goldstone boson in QED. Our review of generalized symmetries is more formal than the ones in other papers. This makes various points explicit and leads to general selection rules. Many results of previous papers are reproduced in detail.
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Мейріс, Антон Жанович. "Теплообмін та теплогідравлічна ефективність пучків труб з поверхневими заглибленнями". Thesis, Інститут технічної теплофізики НАН України, 2018. https://ela.kpi.ua/handle/123456789/38181.
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Робота виконана в Національному технічному університеті України «Київський політехнічний інститут імені Ігоря Сікорського» МОН України на кафедрі фізики енергетичних систем і в Інституті технічної теплофізики НАН України у відділі високотемпературної термогазодинаміки. Захищена в Інституті технічної теплофізики НАН України.<br>Дисертація присвячена експериментальному та теоретичному дослідженню теплообміну та гідродинаміки при поперечному обтіканні одиночної труби та пучку труб із поверхневими заглибленнями.
Теоретично досліджено теплообмін та гідродинаміку при поперечному обтіканні одиночної труби із поверхневими заглибленнями у формі усіченого конусу за допомогою комп’ютерного пакету ANSYS CFX. Проведено верифікацію моделей турбулентності. Наведено результати досліджень вихрової структури потоку, точки відриву потоку, зони зворотних течій, коефіцієнту лобового опору, коефіцієнту теплообміну.
Проведено експериментальні та теоретичні дослідження теплообміну та гідродинаміки при поперечному обтіканні п’ятирядного пучку труб із поверхневими заглибленнями. Отримані дані щодо коефіцієнтів гідравлічного опору пучка та коефіцієнтів теплообміну по рядах та для пучка в цілому.
Проведено верифікацію комп’ютерної моделі по експериментальним даним.
Розроблено інженерну методику розрахунку рекуператора газотурбінної установки та проведено оцінку зниження його маси за рахунок нанесення заглиблень.<br>The dissertation is devoted to the experimental and theoretical study of heat transfer and hydrodynamics at the cross-flow of a single tube and a tube bundle with surface indentations.
Heat transfer and hydrodynamics were studied theoretically at the cross-flow of a single tube with surface indentations in the form of a truncated cone using the ANSYS CFX computer package. Verification of turbulence models is carried out. The results of studies of the vortex structure of the flow, the point of separation of the flow, the zone of reverse flows, the coefficient of the frontal resistance, and the heat transfer coefficient are given.
Experimental and theoretical investigations of heat transfer and hydrodynamics are carried out at the cross-flow of a five-row tube bundle with surface indentations.
The data on the coefficients of the hydraulic resistance of the bundle and of the heat transfer coefficients for rows and for the whole bundle are obtained. Verification of the computer model by experimental data is carried out.
An engineering method for calculation of the gas turbine plant recuperator was developed and an estimation of the decrease in its mass due to the application of depressions was made.
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Brun, Christophe. "Étude expérimentale et numérique de l'interaction forte entre sillages d'obstacles cylindriques." Université Joseph Fourier (Grenoble ; 1971-2015), 1998. http://www.theses.fr/1998GRE10049.
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Cette etude s'interesse aux phenomenes caracteristiques de la formation et de l'interaction des sillages turbulents en aval d'obstacles cylindriques en configuration complexe. Pour le bas regime sous-critique de nombre de reynolds nous effectuons une investigation de la zone de proche sillage de facon a la fois experimentale via des mesures de vitesse par anemometrie laser doppler et numerique via des simulations 2d avec raffinement du maillage en paroi. Dans un premier temps nous etudions le cas de l'interaction forte entre deux cylindres en parallele dont l'ecartement bord a bord est inferieur au diametre. L'effet de blocage se traduit par l'apparition d'un jet inter-tubes. Deux regimes sont identifies par rapport a une valeur critique re#c du nombre de reynolds. En deca de re#c le jet se plaque de facon stable du cote de l'un des cylindres provoquant une disymetrie du double sillage forme en aval. Des nombres de strouhal differents sont retrouves dans la zone arriere de chacun des tubes. Au-dela de re#c le jet adopte un mouvement de battement aleatoire de part et d'autres de l'axe median des tubes. Nous relions l'apparition de ce phenomene d'intermittence a grande echelle de l'ecoulement a la naissance d'instabilites 2d de kelvin-helmholtz au sein de la couche cisaillee decollee. Ces deux effets d'asymetrie et de battement de l'ecoulement (selon le regime) s'estompent au-dela de cinq diametres pour laisser place a un sillage unique qui tend vers une etat de turbulence quasiment developpee. Les phenomenes de melange a grande echelle et de transfert d'energie et dissipation a petite echelle sont favorises par cette configuration d'interaction forte. Enfin, nous etudions experimentalement le cas plus complexe de l'ecoulement au sein et en aval d'un faisceau de tubes en quinconce a des regimes de reynolds equivalents. Les proprietes de melange sont accentuees par rapport au cas geometriquement et hydrodynamiquement equivalent de l'interaction forte entre deux tubes.
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Ndlovu, Isaac. "An examination of prison, criminality and power in selected contemporary Kenyan and South African narratives." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5159.
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Thesis (PhD (English))--University of Stellenbosch, 2010.<br>ENGLISH ABSTRACT: This thesis undertakes a comparative examination of South African and Kenyan auto/biographical narratives of crime and imprisonment. Although some attention is paid to narratives of political imprisonment, the study focuses primarily on autobiographical accounts by criminals, confessional narratives, popular fiction about crime and prison experience, and journalistic accounts of prison life. There is very little critical work at this moment that refers to these forms of prison writing in South Africa and Kenya. Popular prison narratives and to a certain extent the autobiographical in general are characterised by an under-theorised dialecticism. As academic concepts, both the popular and the autobiographical form are characterised by an unstable duality. While the popular has been theorised as being both a field of resistance to power and of consent to its demands, the autobiographical occupies a similar precariously divided position, in this case between fact and fiction, a place where the „I‟ that narrates is simultaneously the subject and object of the narrative. In examining an eclectic body of texts that share the prison as common denominator, my study problematises the tension between self and world, popular and canonical, political and criminal, factual and fictional. In both settings, South Africa and Kenya, the prison as a material and discursive space does not only mirror society but effects shifts and changes in society, and becomes a space of dynamic adaptation and also a locus that disturbs certain hegemonic relations. The way in which the experience of prison opens up to a fundamentally unsettling ambiguity resonates with the ambivalence that characterises both autobiography as genre and the popular as a theoretical concept. My thesis argues that during the entire historical period covered by the narratives that I examine there is a certain excess that attends on the social production of criminality and the practice of imprisonment, both as material realities and as discursive concepts, which allows them to have a haunting effect both on individuals‟ notions of „the self‟ and the constitution of national identities and nationhoods. I argue that the distinction between the colonial and the postcolonial prison is hazy. Therefore a comparative study of Kenyan and South African prison literature helps us understand how modern prisons and notions of criminality in contemporary Africa are intertwined with the broad European colonial project, reflecting larger issues of state power and control over the populace. In relation to South Africa, my study begins with Ruth First‟s 117 Days (1963), and makes a selection of other prisons narratives throughout the apartheid era up to the post-apartheid period which was ushered in by Mandela‟s Long Walk to Freedom (1994). Moving beyond Mandela, I examine other forms of South African crime and prison narratives which have emerged since the publication of Pumla Gobodo-Madikizela‟s A Human Being Died that Night (2003) and Jonny Steinberg‟s The Number (2004). In Kenya, I begin with Ngugi wa Thiongo‟s Detained (1981). I then focus on popular narratives of crime and imprisonment which began with the publication of John Kiriamiti‟s My Life in Crime (1984) up to the first decade of the 21st century, marked yet again by the publication of Kiriamiti‟s My Life in Prison (2004). Besides Kiriamiti‟s two narratives, the other Kenyan texts which I examine are John Kiggia Kimani‟s Life and Times of a Bank Robber (1988) and Prison is not a Holiday Camp (1994), Benjamin Garth Bundeh‟s Birds of Kamiti (1991), and Charles Githae‟s, Comrade Inmate (1994).<br>AFRIKAANSE OPSOMMING: My proefskrif onderneem ‟n vergelykende studie van Suid-Afrikaanse en Keniaanse auto/biografiese narratiewe van misdaad en gevangeneskap. Hoewel aandag tot ‟n mate geskenk word aan verhale van politieke gevangeneskap, is die primêre fokus van die studie eerder op autobiografiese narratiewe deur misdadigers, konfessionele narratiewe, populêre fiksie met betrekking tot misdaad en gevangenis-ondervindinge, sowel as joernalistieke verslae oor gevangenes se lewens agter tralies. Min kritiese werk is tot dusver in verband met hierdie vorme van gevangenis-narratiewe in Suid-Afrika en Kenia gedoen. Populêre prisoniers-narratiewe, en tot ‟n mate autobiografieë oor die algemeen, word deur ‟n onder-geteoriseerde dialektisisme gekenmerk. As akademiese konsepte word beide die populêre en die autobiografiese vorme deur ‟n onstabiele dualisme gekenmerk. Terwyl die populêre tipe geteoretiseer word as sowel ‟n vorm van weerstand teen mag as van toegee daaraan, word aan die autobiografiese tipe ‟n soortgelyke onstabiele, verdeelde rol toegeskryf – in hierdie geval, tussen feitelikheid en fiksie, ‟n plek waar die “ek” wat vertel terselfdertyd die subjek en objek van die verhaal is. Deur middel van ‟n eklektiese versameling van tekste wat die gevangenis as verwysingspunt deel, problematiseer my verhandeling die spanning tussen self en wêreld, die populêre en die gekanoniseerde, die politieke en die kriminele, die feitelike en die fiktiewe. In beide kontekste, Suid-Afrika en Kenia, weerspieël die gevangenis as diskursiewe spasie nie alleenlik die gemeenskapsomgewing nie, maar veroorsaak dit ook veranderings en verskuiwings in die gemeenskap – sodoende word die gevangenis self ‟n ruimte van dinamiese verandering en ‟n plek wat sekere hegemoniese verhoudings versteur. Die manier waarop die ondervinding van gevangeneskap lei tot ‟n fundamentele versteurende dubbelsinningheid resoneer met die dubbelsinnigheid wat beide die autobiografiese as genre en die populêre as teoretiese konsep karakteriseer. My tesis voer aan dat, gedurende die ganse historiese tydperk wat gedek word deur die narratiewe wat ek hier betrag, daar ‟n sekere oormaat is wat die sosiale produksie van misdaad en die toepassing van gevangesetting begelei, beide as stoflike werklikhede en as diskursiewe konsepte, wat hulle toelaat om ‟n kwellende effek uit te oefen beide of individuele mense se sin van „self‟ en die samestelling van nasionale identiteite en nasionaliteite. Ek voer aan dat die onderskeid tussen die koloniale en die postkoloniale gevangenis onduidelik is, en dat ‟n vergelykende studie van Keniaanse en Suid-Afrikaanse gevangenes-narratiewe ons dus help om te verstaan hoe moderne tronke en idees oor misdaad in Afrika deureengevleg is met die breë Europese koloniale projek, en groter kwessies van staatsmag en beheer oor die bevolking weerspieël. In Suid Afrika begin my studie met Ruth First se 117 Days (1963), en maak dan ‟n seleksie van ander gevangenes-narratiewe van die apartheid-era tot en met die post-apartheid oomblik wat deur Mandela se Long Walk to Freedom ingelui word. Ek vestig dan my aandag op ander vorme van Suid-Afrikaanse misdaad- en gevangenes-narratiewe wat sedert die publikasie van Pumla Gobodo-Madikizela se A Human Being Died that Night (2003) en Jonny Steinberg se The Number (2004) verskyn het. In Kenia begin ek met Ngugi wa Thiongo se Detained (1981), en kyk dan ten slotte na populêre narratiewe van misdaad en gevangeneskap wat hulle aanvang vind met die publikasie van John Kiriamiti se My Life in Crime (1984) tot en met die eerste dekade van die 21ste eeu, nogmaals gemerk deur die publikasie van Kiriamiti se My Life in Prison (2004).
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Senve, Vinay. "Coupled Heat Transfer Processes in Enclosed Horizontal Heat Generating Rod Bundles." Thesis, 2013. http://etd.iisc.ac.in/handle/2005/3299.
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In a nuclear fuel cask, the heat generating spent fuel rods are packed in a housing and the resulting bundle is placed inside a cask of thick outer shell made of materials like lead or concrete. The cask presents a wide variation in geometrical dimensions ranging from the diameter of the rods to the diameter of the cask. To make the problem tractable, first the heat generating rod bundle alone is considered for analysis and the effective thermal conductance of the bundle is correlated in terms of the relevant parameters. In the second part, the bundle is represented as a solid of equivalent thermal conductance and the attention is focused on the modelling of the cask. The first part, dealing with the effective thermal conductance is solved using Fluent software, considering coupled conduction, natural convection and surface radiation in the heat generating rod bundle encased in a hexagonal sheath. Helium, argon, air and nitrogen are considered as working media inside the bundle. A correlation is obtained for the critical Rayleigh number which signifies the onset of natural convection. A correlation is also developed for the effective thermal conductance of the bundle, considering all the modes of transport, in terms of the maximum temperature in the rod bundle, pitch-to-diameter ratio, bundle dimension (or number of rods), heat generation rate and the sheath temperature. The correlation covers pitch-to-diameter ratios in the range 1.1-2, number of rods ranging from 19 to 217 and the heat generation rates encountered in practical applications.
The second part deals with the heat transfer modeling of the cask with the bundle represented as a solid of effective (or equivalent) thermal conductance. The mathematical model describes two-dimensional conjugate natural convection and its interaction with surface radiation in the cask. Both Boussinesq and non-Boussinesq formulations have been considered for convection. Numerical solutions are obtained on a staggered mesh with a pressure correction method using a custom-made Fortran code. The surface radiation is coupled to the conduction and convection at the solid-fluid interfaces. Steady-state results are obtained using time-marching. Results for various quantities of interest, namely, the flow and temperature distributions, Nusselt numbers, and interface temperatures, are presented. The Grashof number based on the volumetric heat generation and gap width is varied from 105 to 5 ×109. The emissivities of the interfaces are varied from 0.2-0.8 for the radiative calculations. The solid-to-fluid thermal conductivity ratio for the inner cylinder is varied in the range 5-20 in the parametric studies. Simulations are also performed with thermal conductivity calculated in an iterative manner from bundle parameters. The dimensionless outer wall conductivity ratio is chosen to correspond to cask walls made of lead or concrete. The dimensionless thickness (with respect to gap width) of the outer shell is in the range of 0.0825-1, while the inner cylinder dimensionless radius is 0.2. Air is the working medium in the cask for which the Prandtl number is 0.71. Correlations are obtained for the average temperatures and Nusselt numbers at the inner interface in terms of the parameters. The radiation heat transfer is found to contribute significantly to the heat dissipation.
Books on the topic "Number of bundles"
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Gaitsgory, Dennis, and Jacob Lurie. Weil's Conjecture for Function Fields. Princeton University Press, 2019. http://dx.doi.org/10.23943/princeton/9780691182148.001.0001.
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A central concern of number theory is the study of local-to-global principles, which describe the behavior of a global field K in terms of the behavior of various completions of K. This book looks at a specific example of a local-to-global principle: Weil's conjecture on the Tamagawa number of a semisimple algebraic group G over K. In the case where K is the function field of an algebraic curve X, this conjecture counts the number of G-bundles on X (global information) in terms of the reduction of G at the points of X (local information). The goal of this book is to give a conceptual proof of Weil's conjecture, based on the geometry of the moduli stack of G-bundles. Inspired by ideas from algebraic topology, it introduces a theory of factorization homology in the setting ℓ-adic sheaves. Using this theory, the authors articulate a different local-to-global principle: a product formula that expresses the cohomology of the moduli stack of G-bundles (a global object) as a tensor product of local factors. Using a version of the Grothendieck–Lefschetz trace formula, the book shows that this product formula implies Weil's conjecture. The proof of the product formula will appear in a sequel volume.
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Tretkoff, Paula. Topological Invariants and Differential Geometry. Princeton University Press, 2017. http://dx.doi.org/10.23943/princeton/9780691144771.003.0002.
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This chapter deals with topological invariants and differential geometry. It first considers a topological space X for which singular homology and cohomology are defined, along with the Euler number e(X). The Euler number, also known as the Euler-Poincaré characteristic, is an important invariant of a topological space X. It generalizes the notion of the cardinality of a finite set. The chapter presents the simple formulas for computing the Euler-Poincaré characteristic (Euler number) of many of the spaces to be encountered throughout the book. It also discusses fundamental groups and covering spaces and some basics of the theory of complex manifolds and Hermitian metrics, including the concept of real manifold. Finally, it provides some general facts about divisors, line bundles, and the first Chern class on a complex manifold X.
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Francesca, Mazza. Ch.9 Assignment of rights, transfer of obligations, assignment of contracts, s.1: Assignment of rights, Art.9.1.6. Oxford University Press, 2015. http://dx.doi.org/10.1093/law/9780198702627.003.0175.
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This commentary analyses Article 9.1.6 of the UNIDROIT Principles of International Commercial Contracts (PICC) concerning assignment of a right without individual specification. According to Art 9.1.6, a number of rights may be assigned without individual specification, provided such rights can be identified as rights to which the assignment relates at the time of the assignment or when they come into existence. The provision clarifies that the assignment of a bundle of rights is effective. It does not matter whether the bundle of rights consists of existing or future rights, or both. The PICC do not offer an explicit answer for what happens if the bundle of rights includes some rights which cannot be identified as rights to which the assignment relates (whereas the remaining rights can). This commentary discusses the principle of partial validity as it applies with respect to the assignment of a bundle of rights (as opposed to the complete invalidity of the assignment).
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Phillips, Carly. Hot Zone Bundle: Hot Stuff Hot Number Hot Item Hot Property. Harlequin Enterprises ULC, 2014.
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Phillips, Carly. Hot Zone Bundle: Hot Stuff Hot Number Hot Item Hot Property. Harlequin Enterprises, Limited, 2014.
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Get Your Colors Right, Kid: Color by Number Activity Books for Kids Bundle. Speedy Publishing LLC, 2019.
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Eureka Math Squared, California Edition, Level 3, Learn & Digital Bundle: Units of Any Number. Great Minds, 2023.
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Eureka Math Squared, California Edition, Level 5, Learn & Digital Bundle: Fractions Are Numbers. Great Minds, 2023.
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Eureka Math Squared, New York Next Gen, Level 3, Learn & Digital Bundle: Units of Any Number. Great Minds, 2023.
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Guffey, Mary Ellen, and Carolyn M. Seefer. Bundle : Business English , 11th + Partial Student Key: Answers to Odd-Numbered Reinforcement. Cengage South-Western, 2013.
Find full textBook chapters on the topic "Number of bundles"
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Neumann, Frank, and Ulrich Stuhler. "Moduli stacks of vector bundles and Frobenius morphisms." In Algebra and Number Theory. Hindustan Book Agency, 2005. http://dx.doi.org/10.1007/978-93-86279-23-1_9.
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Deninger, Christopher, and Annette Werner. "Line Bundles and p-Adic Characters." In Number Fields and Function Fields—Two Parallel Worlds. Birkhäuser Boston, 2005. http://dx.doi.org/10.1007/0-8176-4447-4_7.
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Alam, Md Jawaherul, Martin Fink, and Sergey Pupyrev. "The Bundled Crossing Number." In Lecture Notes in Computer Science. Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-50106-2_31.
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Arroyo, Alan, and Stefan Felsner. "Approximating the Bundled Crossing Number." In WALCOM: Algorithms and Computation. Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-96731-4_31.
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Simpson, Carlos. "Homotopy Over the Complex Numbers and Generalized de Rham Cohomology." In Moduli of Vector Bundles. CRC Press, 2023. http://dx.doi.org/10.1201/9781003419983-17.
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Yoshioka, Kōta. "Numbers of Fq-Rational Points of the Moduli of Stable Sheaves On Elliptic Surfaces." In Moduli of Vector Bundles. CRC Press, 2023. http://dx.doi.org/10.1201/9781003419983-20.
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Benincasa, Fabrizio, Matteo De Vincenzi, and Gianni Fasano. "The Historic Lighthouses of the Italian Coasts." In Monitoring of Mediterranean Coastal Areas: Problems and Measurement Techniques. Firenze University Press, 2024. https://doi.org/10.36253/979-12-215-0556-6.49.
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The tall tower building with an intense light source on the top, visible far away, called a lighthouse in English, takes its name in the Romance languages of faro. The fuels used to produce lighting have progressively adapted to the times: bundles of dry wood, olive oil, wax candles, sperm whale fat, paraffin oil, acetylene, arriving to electricity. The lighthouses didn’t only have positive aspects; in fact, they not only facilitated bearings during night navigation, but also indicated to the pirates the coastal cities to plunder. This gave rise to a sort of "land piracy" as "prankster" characters lit "fake beacons" on reefs, shoals, etc. waters where ships were stranded and were therefore more easily plundered. This work shows the current number of lighthouses in Italy, giving greater emphasis to the Italian historic lighthouses, which, by definition, are those that meet at least three of the characteristics established by IALA. As in other European countries, also in Italy the lighthouse lantern was often placed on the top of bell towers of the churches along the coastline. The oldest Italian lighthouses are on the Tyrrhenian coast the lighthouse of Rome Port and on the Adriatic coast the lighthouse of Ravenna Port. Obviously, we will only mention the lighthouses, which in our opinion are the most important and given the historicity of these we will only deal with the "bright" lighthouses, outlining the historical-geographical context within which they were built.
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Bost, Jean-Benoît. "Geometry of Numbers and θ-Invariants." In Theta Invariants of Euclidean Lattices and Infinite-Dimensional Hermitian Vector Bundles over Arithmetic Curves. Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-44329-0_3.
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Maillot, Vincent, and Damian Roessler. "On the Order of Certain Characteristic Classes of the Hodge Bundle of Semi-Abelian Schemes." In Number Fields and Function Fields—Two Parallel Worlds. Birkhäuser Boston, 2005. http://dx.doi.org/10.1007/0-8176-4447-4_14.
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Schneider, Jan, and Holger Kolb. "“Selecting by Origin” Revisited: On the Particularistic Turn of German Labour Migration Policy." In IMISCOE Research Series. Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-26002-5_9.
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AbstractFollowing a decade in which German labour migration policy has developed towards a universalistic regime that applied similar conditions towards most third country nationals applying for admission, we observe a slow but steady return of ethnic selectivity and particularistic features in this area. Although human capital remains a centrepiece of the bundle of regulations and institutional settings which govern the process of selecting labour migrants, the factor of the respective country of origin of applicants has regained importance over the last few years. This Chapter explores a number of deviations from a legal framework, which in principle is universalist and claims to put merits, certificates and employers’ demand first. We demonstrate, however, that starting conditions for obtaining a work visa turn out to be unequal, as they positively discriminate particular nationalities. This prominence of ethnic origin in migrant admission policies vis-à-vis third countries is a rather recent phenomenon in Germany, but something which could be observed in other EU countries – not least in Southern EU Member States – already for some years. These observations tend to counter the proverbial North-South divide, suggesting rather unexpected policy convergences within the EU.
Conference papers on the topic "Number of bundles"
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Hock, V. F., H. Cardenas, E. Sear, and R. Knoll. "Experimental Heat Transfer Model for Optimizing Heat Exchanger Tubing." In CORROSION 1993. NACE International, 1993. https://doi.org/10.5006/c1993-93515.
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ABSTRACT Shell-and-tube heat exchangers are frequently employed to supply domestic hot water for large buildings such as hospitals, restaurants, schools, and office complexes. An optimal heat exchanger transfers heat from the source to the target material with minimal losses to the surrounding environment. The actual amount of heat transferred varies with the heat exchanger design, the specific applications desired, the physical limits as directed by thermal efficiency, and finally, with fouling (corrosion bi-product and/or scaling). In order to combat the problems of corrosion and scale build-up, both industry, as well as the United States military, have investigated the possibility of coating domestic water heat exchanger bundles in order to mitigate heat transfer reductions and premature failures. The feasibility of this venture is constrained by the thermal insulating properties of candidate coating materials relative to the cost savings which they provide. In order to properly determine the overall efficacy of these materials as corrosion/scale inhibitors, an experimental apparatus has been designed, assembled, and calibrated in order to provide a controlled crossflow environment with respect to corrosivity (Langelier index), Reynolds number of the flow over a test cylinder, and isothermal wall temperature.
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Zhao, Weihuan, and Khaled Almahmoud. "Heat Transfer Analyses of a 3D Graphene-Carbon Nanotube Pillared Structure." In ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-87029.
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This work is aimed towards studying and analyzing the heat transfer performance in a novel 3D graphene-carbon nanotube (CNT) pillared structure. Although both graphene and CNT are known to have high thermal conductivity in in-plane and along the axis, respectively, they have low thermal conductivities in the other directions. Hence, the 3D graphene-CNT structure will have high thermal conductivities in both in-plane and out-of-plane directions due to the pillared architecture. It can be applied to small-scale electronic devices for high efficient heat dissipation and/or exchange. The pillared structure consists of few-layer graphene (FLG) and bundles of CNTs. CNT bundles connect between two sheets of FLG. The heat transfer performance of the structure was investigated through a continuum model by COMSOL Multiphysics. Parameter studies were conducted to determine the optimum graphene-CNT configuration, including number of CNTs in each bundle, number of bundles in the structure, distance between bundles (a.k.a. inter-pillar distance “IPD”), length of CNT, and the arrangement of CNT bundles. Results of the simulations concluded that (1) the reduced IPD could prevent the in-plane heat spreading, (2) the increased number of CNTs could enhance the axial-direction thermal transport, and (3) the arrangement of CNT bundles between FLG sheets (e.g. shifting one row of CNT bundles) has minor impacts on the overall heat transfer performance of the structure.
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Li, Xiaoxi, Jiming Wen, Puzhen Gao, and Yibo Yin. "Research on Natural Frequency Characteristics of Spiral Tube Bundles." In 2024 31st International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2024. http://dx.doi.org/10.1115/icone31-134953.
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Abstract Liquid metal reactors (LMR), with the significant advantages in high safety and good economic benefits, has obvious advantages and broad application prospects in the fourth generation nuclear power systems. Spiral tube steam generator is one of the most important equipment in LMR, which are composed of spiral heat transfer tubes, inner and outer cylinders, feedwater headers, steam headers, and other structures. Due to their compact structure and high heat transfer efficiency, they are conducive to equipment miniaturization and have been widely used in different reactors in various countries. Due to the impact of the shell side fluid in the steam generator on the tube bundle, it is inevitable to cause flow induced vibration (FIV), resulting in thinning or even rupture of the tube wall, thereby shortening the service life or even failure of the steam generator. Therefore, the study of the vibration characteristics of spiral tube bundles is of great significance. The natural frequency of the tube bundle is an important parameter in FIV analysis. The heat transfer tubes of the spiral tube steam generator are made of spiral winding, and the positions between adjacent tubes are complex and variable. The winding direction between adjacent layers of the spiral heat transfer tubes can be in the same or opposite direction, so their spatial structure is complex. This article simulates and calculates the natural frequency of spiral heat transfer tubes in air and lead bismuth, and studies the influence of geometric structural parameters on their natural frequency. Based on simplifying constraints at both ends of the spiral tube bundles to fixed support, the computational fluid dynamics (CFD) simulation was carried out to reveal the effect mechanism of support number, spiral radius and spiral rising angle, on natural frequency of spiral tube bundles in air. The results indicate that an increase in spiral radius leads to a decrease in natural frequency, while an increase in support number leads to a significant increase in natural frequency, and the spiral rise angle has little effect on the natural frequency. Therefore, we can improve the stability of the spiral tube bundles by increasing support number or reducing spiral radius. Through CFD simulation calculation, the influence mechanism of tube bundle structural parameters on the natural frequency of spiral tube bundles in liquid metal environments was studied. The increase of layer pitch ratio and the same layer pitch ratio led to an increase in natural frequency. The research results provide data reference for the prediction of the natural frequency of heat transfer tubes and the study of FIV of tube bundles, which are of great significance for avoiding the failure of heat transfer tubes.
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Pacio, J., M. Daubner, T. Wetzel, et al. "Experimental Nusselt Number in Rod Bundles Cooled by Heavy-Liquid Metals." In 2018 26th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icone26-82213.
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A detailed safety assessment of innovative Generation IV reactor designs with heavy-liquid metal coolants, such as lead and lead-bismuth eutectic (LBE), requires an evaluation of the maximum core temperature in several postulated scenarios. Considering the complex geometry of fuel assemblies (FAs), and the low Prandtl number of the coolants, this flow scenario is challenging for the models used in numerical simulations, e.g. for relating the turbulent transport of momentum and heat. Thus, reliable experimental data are needed for validation. In recent years, a series of comprehensive heat transfer tests in fuel pin bundle simulators was performed at ENEA (Italy) and KIT (Germany) in the framework of the European collaborative projects THINS and SEARCH. Both grid and wire spacer geometries are considered, in a wide range of operating conditions (temperature, flow velocity and power density) representative of the ALFRED and MYRRHA fuel assemblies, in natural and forced-convective flow regimes. Although different experimental approaches were followed by each group (e.g. thermocouple position and average data treatment), there is a relatively good agreement on results in the overlapping regions. These experimental studies indicate that the mean Nusselt number is in well agreement with the predictions of empirical correlations developed for sodium systems. In particular, for wire-spaced FA, heat transfer results show values close to the Kazimi-Carelli correlation both for low and high flow rates at ENEA and KIT respectively. For grid-spaced FA, results are more in agreement with Ushakov correlation. Furthermore, large temperature differences are measured by thermo-couples installed at selected rods and sub-channels. A discussion on the influences of the spacer design and bundle size is included. This wide comparison allows an overview of the research on the HLM cooled fuel assembly in Europe.
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Hata, Koichi, Katsuya Fukuda, and Tohru Mizuuchi. "Natural Convection Heat Transfer From Vertical 5×5 Rod Bundles in Liquid Sodium." In 2016 24th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/icone24-60180.
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Natural convection heat transfer from vertical 5×5 rod bundles in liquid sodium was numerically analyzed for two types of the bundle geometry (equilateral square and triangle arrays, ESA and ETA). The unsteady laminar three dimensional basic equations for natural convection heat transfer caused by a step heat flux were numerically solved until the solution reaches a steady-state. The PHOENICS code was used for the calculation considering the temperature dependence of thermophysical properties concerned. The 5×5 test rods for diameter (D = 7.6 mm), heated length (L = 200 mm) and L/d (= 26.32) were used in this work. The surface heat fluxes for each cylinder were equally given for a modified Rayleigh number, (Rf,L)ij and (Rf,L)5×5,S/D, ranging from 3.08 × 104 to 4.19 × 107 (q = 1 × 104∼7 × 106 W/m2) in liquid temperature (TL = 673.15 K). The values of S/D, which are ratios of the diameter of flow channel for bundle geometry to the rod diameter, for vertical 5×5 rod bundles were ranged from 1.8 to 6 on each bundle geometry. The spatial distribution of local and average Nusselt numbers, (Nuav)ij and (Nuav,B)5×5,S/D, on vertical rods of a bundle was clarified. The average value of Nusselt number, (Nuav)ij and (Nuav,B)5×5,S/D, for two types of the bundle geometry with various values of S/D were calculated to examine the effect of the bundle geometry, S/D, (Rf,L)ij and (Rf,L)5×5,S/D on heat transfer. The bundle geometry for the higher (Nuav,B)5×5,S/D value under the condition of S/D = constant was examined. The correlations for (Nuav,B)5×5,S/D for two types of bundle geometry above mentioned including the effects of (Rf,L)5×5,S/D and S/D were developed. The correlations can describe the theoretical values of (Nuav,B)5×5,S/D for two types of the bundle geometry for S/D ranging from 1.8 to 6 within −11.77 to 13.34 % difference.
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Gravel, E. M., and T. D. Papathanasiou. "A General Correlation for the Hydraulic Permeability of Arrays of Elliptical Fiber Bundles." In ASME 2000 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/imece2000-2710.
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Abstract A computational analysis of viscous flow through arrays of fiber bundles is carried out using the Boundary Element Method. We consider fiber bundles of elliptical cross section, each made up of up to 350 individual filaments. Such arrays are dual-porosity systems, characterized by different inter- (ϕi) and intra-tow (ϕt) porosities as well as by varying number (Nf) of filaments within each bundle. Investigating the influence of these parameters on the hydraulic permeability of hexagonal arrays of such bundles is the subject of our simulations. The results are compared to earlier analytical models and a good agreement is found. A dimensionless correlation is proposed and the computed permeabilities for bundles of aspect ratio λ = 2 and λ = 3 are shown to fall on a single master curve. This offers a generalized model for the calculation of the permeability of such dual porosity systems from knowledge of ϕi, ϕt, λ and Nf.
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Hata, Koichi, Katsuya Fukuda, and Tohru Mizuuchi. "Natural Convection Heat Transfer From Vertical 7x7 Rod Bundles in Liquid Sodium." In 2017 25th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/icone25-66180.
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Natural convection heat transfer from vertical 7×7 rod bundle in liquid sodium was numerically analyzed to optimize the thermal-hydraulic design for the bundle geometry with equilateral square array, ESA. The unsteady laminar three dimensional basic equations for natural convection heat transfer caused by a step heat flux were numerically solved until the solution reaches a steady-state. The PHOENICS code was used for the calculation considering the temperature dependence of thermo-physical properties concerned. The 7×7 test rods for diameter (D = 7.6 mm), heated length (L = 200 mm) and L/d (= 26.32) were used in this work. The surface heat fluxes for each cylinder were equally given for a modified Rayleigh number, (Rf,L)ij and (Rf,L)Nx×Ny,S/D, ranging from 3.08×104 to 4.28×107 (q = 1×104∼7×106 W/m2) in liquid temperature (TL = 673.15 K). The values of S/D, which are ratios of the diameter of flow channel for bundle geometry to the rod diameter, for vertical 7×7 rod bundle were ranged from 1.8 to 6 on the bundle geometry with equilateral square array. The spatial distribution of average Nusselt numbers for a vertical single cylinder of a rod bundle, (Nuav)ij, and average Nusselt numbers for a vertical rod bundle, (Nuav,B)Nx×Ny,S/D, were clarified. The average value of Nusselt number, (Nuav)ij and (Nuav,B)Nx×Ny,S/D, for the bundle geometry with various values of S/D were calculated to examine the effect of array size, bundle geometry, S/D, (Rf,L)ij and (Rf,L)Nx×Ny,S/D on heat transfer. The bundle geometry for the higher (Nuav,B)Nx×Ny,S/D value under the condition of S/D = constant was examined. The general correlations for natural convection heat transfer from a vertical Nx×Ny rod bundle with the equilateral square and triangle arrays including the effects of array size, (Rf,L)Nx×Ny,S/D and S/D were derived. The correlations for vertical Nx×Ny rod bundles can describe the theoretical values of (Nuav,B)Nx×Ny,S/D for each bundle geometry in the wide analytical range of S/D (= 1.8 to 6) and the modified Rayleigh number ((Rf,L)Nx×Ny,S/D = 3.08×104 to 4.28×107) within −9.49 to 10.6 % differences.
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Oengören, Abdullah, and Samir Ziada. "Flow Periodicity and Acoustic Resonance in Parallel Triangle Tube Bundles." In ASME 1997 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/imece1997-0111.
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Abstract Parallel triangle tube arrays with pitch ratios in the range of 1.2 to 4.2 have been tested at Reynolds numbers up to 90000 to investigate the vorticity shedding and acoustic resonance mechanisms. The tests included measurements of the pressure fluctuations on the tubes and on the test section wall, as well as extensive flow visualisation and hot film measurements of the unsteady flow activities. Three different components of flow periodicities have been observed. The flow periodicity with the highest Strouhal number (S3) is caused by a shear layer instability and is the weakest component. The S2 component is associated with small scale vortex shedding at the first row. The third component has the lowest Strouhal number (S1) and is the strongest. It is generated by large scale, alternating vortex shedding at deeper rows, and it becomes dominant at all rows at high Reynolds numbers. For tube arrays with pitch ratio less than 3.4, the onset of acoustic resonances could not be related to the natural flow periodicities mentioned above. This behaviour is in contrast with that of normal triangle arrays, but similar to the acoustic behaviour of in-line arrays. The similarity with in-line arrays seems to stem from the fact that both arrays allow the flow to proceed along free flow lanes between the tube columns, resulting in a similar acoustic resonance mechanism. Strouhal number charts for the natural vorticity shedding and the onset of acoustic resonances have been developed.
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Liu, Wei, Jane H. Davidson, and F. A. Kulacki. "Thermal Characterization of Prototypical ICS Systems With Immersed Heat Exchangers." In ASME 2004 International Solar Energy Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/isec2004-65030.
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Natural convection is measured in an enclosure that represents an integral collector storage solar system with an immersed heat exchanger. The enclosure has an aspect ratio of 9.3:1 and is inclined 30 deg to the horizontal. Heat transfer coefficients for bundles of 240 tubes are obtained for a range of transient operating modes and pitch-to-diameter ratios of 1.5, 2.4, and 3.3. Results for isothermal and stratified enclosures yield a correlation for the overall Nusselt number, NuD=(2.45±0.03)RaD0.188,230≤RaD≤9800. Nusselt numbers are three times larger than those for a similarly configured single-tube and an eight-tube bundle. This increase is attributed to stronger fluid motion within the bundle and greater overall circulation rates in the enclosure.
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Xie, Xiaoyang, AnXiang Ma, Houjian Zhao, Xiaowei Li, and Xinxin Wu. "Experimental Study of the Bistable Phenomenon in Cross Flow Over Inline Tube Bundle With P/D = 1.4." In 2022 29th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/icone29-92456.
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Abstract Helical tube bundles are usually used for intermediate heat exchangers (IHXs) of High Temperature Gas-cooled Reactors (HTGRs) due to its compactness and low thermal stresses. To clarify the influences of smaller tube pitches, experiments of cross flow over tube bundle with pitch to diameter ratio (P/D) of 1.4 were carried out in a wind tunnel. The time-averaged pressure, pressure fluctuations, and velocity distributions were measured in the fully developed region of the tube bundle. The flow pattern in tube bundles will vary with the Reynolds number. The flow field tends to show an oblique flow phenomenon when Re = 10285, 18000, 44571 and 52500. The turbulent wakes over left four tube layers tend to flow left while the turbulent wakes over right four tube layers tends to flow right. When Re = 36000, the oblique flow phenomenon of the flow field diminished. When Re = 25285, two obvious quasi-stable flow patterns were observed according to the measured surface pressure and the velocity distributions measured by Particle Image Velocimetry (PIV).
Reports on the topic "Number of bundles"
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James-Scott, Alisha, Rachel Savoy, Donna Lynch-Smith, and tracy McClinton. Impact of Central Line Bundle Care on Reduction of Central Line Associated-Infections: A Scoping Review. University of Tennessee Health Science Center, 2021. http://dx.doi.org/10.21007/con.dnp.2021.0014.
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Purpose/Background Central venous catheters (CVC) are typical for critically ill patients in the intensive care unit (ICU). Due to the invasiveness of this procedure, there is a high risk for central line-associated bloodstream infection (CLABSI). These infections have been known to increase mortality and morbidity, medical costs, and reduce hospital reimbursements. Evidenced-based interventions were grouped to assemble a central line bundle to decrease the number of CLABSIs and improve patient outcomes. This scoping review will evaluate the literature and examine the association between reduced CLABSI rates and central line bundle care implementation or current use. Methods A literature review was completed of nine critically appraised articles from the years 2010-2021. The association of the use of central line bundles and CLABSI rates was examined. These relationships were investigated to determine if the adherence to a central line bundle directly reduced the number of CLABSI rates in critically ill adult patients. A summary evaluation table was composed to determine the associations related to the implementation or current central line bundle care use. Results Of the study sample (N=9), all but one demonstrated a significant decrease in CLABSI rates when a central line bundle was in place. A trend towards reducing CLABSI was noted in the remaining article, a randomized controlled study, but the results were not significantly different. In all the other studies, a meta-analysis, randomized controlled trial, control trial, cohort or case-control studies, and quality improvement project, there was a significant improvement in CLABSI rates when utilizing a central line bundle. The extensive use of different levels of evidence provided an excellent synopsis that implementing a central line bundle care would directly affect decreasing CLABSI rates. Implications for Nursing Practice Results provided in this scoping review afforded the authors a diverse level of evidence that using a central line bundle has a direct outcome on reducing CLABSI rates. This practice can be implemented within the hospital setting as suggested by the literature review to prevent or reduce CLABSI rates. Implementing a standard central line bundle care hospital-wide helps avoid this hospital-acquired infection.
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Rudisill, Tracy, Gene Daniel, and Patrick O'Rourke. Evaluation of Changes to the MTR Fuel Dissolution Flowsheet to Increase the Number of L-Bundles Charged to a Dissolver. Office of Scientific and Technical Information (OSTI), 2020. http://dx.doi.org/10.2172/1630276.
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Brown, R. J. L51598 Tow Methods Design Guide for the Installation of Offshore Pipelines. Pipeline Research Council International, Inc. (PRCI), 1989. http://dx.doi.org/10.55274/r0010093.
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In an effort to progress the development of hydrocarbon fields found in water depths beyond 1000 feet, the oil and gas industry is considering cost effective methods of subsea pipeline installation. As an established and reliable oil and gas transportation system, the pipeline will be an important factor in deepwater development. Surface installation methods are expected to become costly in deepwater due to the necessary equipment modifications and vessel requirements which are synonymous with increased tension capability and deepwater station keeping ability. This estimated increase in installation costs has spurred interests in alternative pipeline installation methods that possess the potential for economic competitiveness. Limiting parameters for single as well as bundled pipeline configurations are evaluated for surface, near-surface, mid-depth, off-bottom and bottom tow methods of pipeline installation. The evaluation shows that the viable towing methods for construction of offshore pipelines include the mid-depth and bottom tow methods. Buckle collapse criteria should be utilized in the design of deepwater pipelines to achieve low submerged weights with minimum buoyancy requirements. Low submerged weight provides the maximum pipe tow string length, reducing the number of mid-line connections. A cost estimating program in LOTUS 1-2-3 format is included with this study. The costing program generates cost for each tow method based on user specified pipeline parameters. The cost program also includes J-lay estimating capabilities for single pipelines.