Littérature scientifique sur le sujet « Gravità intermedia »
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Articles de revues sur le sujet "Gravità intermedia"
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Bronner, R., F. Dreger-Jauffret et E. Pfirsch. « Lack of gravitropic response of tumour roots of Forsythia intermedia : cytological evidence for this behaviour ». Canadian Journal of Botany 65, no 1 (1 janvier 1987) : 143–49. http://dx.doi.org/10.1139/b87-020.
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Tumours of Forsythia intermedia Zab. consist of clusters of roots characterized by limited growth. These roots are agravitropic and have a nontypical cap without starch. Placed in moisture, the roots elongate in the same direction as they had on the plant, without any gravitropic curvature. Elongated roots have a caplike area, the cells of which exhibit amyloplasts. The absence of gravitropic response of the elongated roots was confirmed experimentally. Amyloplasts of the columella cells do not sediment in the direction of gravity, even after modification of the position of the root with respect to gravity. The reason for this agravitropism of Forsythia intermedia tumour roots is discussed in relation to their cytological features.
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Jang, Sujin, et E. Young Song. « Gravity with Intermediate Goods Trade ». East Asian Economic Review 21, no 4 (31 décembre 2017) : 295–315. http://dx.doi.org/10.11644/kiep.eaer.2017.21.4.332.
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Conconi, Paola, Glenn Magerman et Afrola Plaku. « The Gravity of Intermediate Goods ». Review of Industrial Organization 57, no 2 (11 juin 2020) : 223–43. http://dx.doi.org/10.1007/s11151-020-09762-2.
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Pethő, Ágnes. « The Vertigo of the Single Image : From the Classic Narrative “Glitch” to the Post-Cinematic Adaptations of Paintings ». Acta Universitatis Sapientiae, Film and Media Studies 6, no 1 (1 août 2013) : 65–90. http://dx.doi.org/10.2478/ausfm-2014-0005.
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Abstract As a possible cross section of cinematic narratology and the theory of intermediality the following essay assesses some of the effects of foregrounding the single, intermedial image within film. Specific figurations of intermediality that are experienced via the consciousness of single images, or some kind of “imageness” (i.e. as “intermedial references”) are presented as well as the modes in which they can interact with the narrative structure of a film. This interaction ranges from a momentary interference with the narrative structure of a film to disrupting it altogether; it may consist in constituting the gravity centre of a plot, or even in becoming the “canvas” for a palimpsest of narrative modes and narratives
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Angenent, S. B., et D. G. Aronson. « Intermediate asymptotics for convergent viscous gravity currents ». Physics of Fluids 7, no 1 (janvier 1995) : 223–25. http://dx.doi.org/10.1063/1.868722.
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Jamil, Mubasher, Davood Momeni et Ratbay Myrzakulov. « Warm Intermediate Inflation in F(T) Gravity ». International Journal of Theoretical Physics 54, no 4 (23 août 2014) : 1098–112. http://dx.doi.org/10.1007/s10773-014-2303-6.
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Greaney, Theresa M., et Kozo Kiyota. « The gravity model and trade in intermediate inputs ». World Economy 43, no 8 (25 mars 2020) : 2034–49. http://dx.doi.org/10.1111/twec.12947.
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LI, GUANGYU, et HAIBIN ZHAO. « CONSTRAINT ON INTERMEDIATE-RANGE GRAVITY FROM EARTH–SATELLITE AND LUNAR ORBITER MEASUREMENTS, AND LUNAR LASER RANGING ». International Journal of Modern Physics D 14, no 10 (octobre 2005) : 1657–66. http://dx.doi.org/10.1142/s0218271805007176.
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In the experimental tests of gravity, there have been considerable interests in the possibility of intermediate-range gravity. In this paper, we use the earth–satellite measurement of earth gravity, the lunar orbiter measurement of lunar gravity, and lunar laser ranging measurement to constrain the intermediate-range gravity from λ = 1.2 × 107 m –3.8 × 108 m . The limits for this range are α = 10-8–5 × 10-8, which improve previous limits by about one order of magnitude in the range λ = 1.2 × 107 m –3.8 × 108 m .
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Van Beeck, J., V. Prat, T. Van Reeth, S. Mathis, D. M. Bowman, C. Neiner et C. Aerts. « Detecting axisymmetric magnetic fields using gravity modes in intermediate-mass stars ». Astronomy & ; Astrophysics 638 (juin 2020) : A149. http://dx.doi.org/10.1051/0004-6361/201937363.
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Context. Angular momentum (AM) transport models of stellar interiors require improvements to explain the strong extraction of AM from stellar cores that is observed with asteroseismology. One of the frequently invoked mediators of AM transport are internal magnetic fields, even though their properties, observational signatures, and influence on stellar evolution are largely unknown. Aims. We study how a fossil, axisymmetric internal magnetic field affects period spacing patterns of dipolar gravity mode oscillations in main sequence stars with masses of 1.3, 2.0, and 3.0 M⊙. We assess the influence of fundamental stellar parameters on the magnitude of pulsation mode frequency shifts. Methods. We computed dipolar gravity mode frequency shifts due to a fossil, axisymmetric poloidal–toroidal internal magnetic field for a grid of stellar evolution models, varying stellar fundamental parameters. Rigid rotation was taken into account using the traditional approximation of rotation, and the influence of the magnetic field was computed using a perturbative approach. Results. We find magnetic signatures for dipolar gravity mode oscillations in terminal-age main sequence stars that are measurable for a near-core field strength larger than 105 G. The predicted signatures differ appreciably from those due to rotation. Conclusions. Our formalism demonstrates the potential for the future detection and characterization of strong fossil, axisymmetric internal magnetic fields in gravity-mode pulsators near the end of core-hydrogen burning from Kepler photometry, if such fields exist.
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Zaninović, Vinko. « Facilitating trade in intermediate goods ». Pomorstvo 36, no 2 (23 décembre 2022) : 271–78. http://dx.doi.org/10.31217/p.36.2.11.
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A side effect of economic globalisation and new information and communication technologies is the increasing fragmentation of the production process across different countries and continents, contributing to the rise of trade in intermediate goods, which has increased to almost 2/3 of total world trade. Most of this trade, i.e., intermediate goods, are transported by sea. Maritime trade is one of the most economical but also complex ways of trading and transporting goods, requiring good coordination, various stops and controls, transhipments, storage, ICT technology to track the cargo, etc. Therefore, the objective of this paper is to quantify the impact of trade facilitation on trade in intermediate goods on the sample of EU28 countries, using biennial data for the period 2010-2018. We estimate augmented gravity model on bilateral trade data using a Poisson Pseudo Maximum Likelihood (PPML) estimator. Our results suggest that, as expected, logistics, and in particular ICT development, has a significant and positive effect on trade in intermediate inputs, when controlling for other variables in the gravity model such as GDP of trading partners, distance, contiguity, existence of a free trade agreement, exchange rate, and common cultural proxies. Our results support the global trend of development and investment in logistics, and, in particular, new ICT technologies, which can not only contribute to the continued growth of trade in intermediates, but also help mitigate the negative effects of recent global economic shocks.
Thèses sur le sujet "Gravità intermedia"
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GERMANO, RICCARDO. « La responsabilità per omesso impedimento dell'evento reato ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2021. http://hdl.handle.net/10281/314887.
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La trattazione ha ad oggetto la responsabilità penale per omesso impedimento del reato e per omesso impedimento dell’evento concausato dall’azione criminosa di un terzo, nella giurisprudenza e nella dottrina italiana. Dopo un approfondimento sul controverso concetto di omissione nel diritto penale, il lavoro affronta gli orientamenti di giurisprudenza e di dottrina sull’omesso impedimento dell’evento-reato, ricostruito a partire dagli istituti della commissione mediante omissione e del concorso di persone nel reato. Il tema viene, infine, analizzato dalla prospettiva dell’omissione propria, proponendo un inquadramento del fenomeno all’interno delle “omissioni intermedie”.The thesis deals with the criminal liability for failure to prevent crimes and failure to prevent events caused by criminal actions, in the Italian case law and literature. After a study on the controversial concept of “omission” in criminal law, the thesis addresses the judgements and the scholarship based on the commission by omission and on the criminal complicity. Eventually, the topic is addressed from the perspective of the “offences of failing to act”, suggesting the framework of the “omission of medium gravity” for the failure to prevent crimes.
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Sartelet, Karine Nathalie. « Intermediate modelling of gravity wave propagation and dissipation in the middle atmosphere ». Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.620334.
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Rabaey, Gregory Francis. « The observed properties of the intermediate-degree gravity modes and their relevance to the solar neutrino paradox ». Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184730.
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Intermediate-degree g-modes (those with angular order ℓ ≈ 30) were first observed in the late 1970's by Hill and Caudell (1979). However, it wasn't until 1986 that a preliminary survey was made of the 1979 differential radius observations (see Bos 1982) and a set of 4 multiplets exhibiting mode-locking was classified by Hill (1986). These multiplets with angular order ℓ ≈ 30 and eigenfrequencies of ≈350 μHz were used as a starting point for the comprehensive analysis discussed in this work. This comprehensive study culminated in the classification of a set of 20 intermediate-degree g-mode multiplets containing over 600 normal modes of oscillation. Each of these multiplets was found to contain mode-coupled sections. Of more importance, however, are the internal properties of the Sun that can be inferred from this large body of classified modes. In this work two significant consequences will be discussed. Because these modes of oscillation are localized within the inner 50% of the Sun by radius and because of their large temperature eigenfunctions implied by the observed phase-locking, these modes of oscillation provide a modification of the effective temperature profile defined for a given process in the Sun. One of these processes is the ⁸B neutrino production. The second consequence of these observations is a predicted periodic modulation of the neutrino production rates. The existence of a large set of mode-coupled gravity modes will lead to a low-frequency modulation of neutrino production rates which may account for the observed periodicity in the ⁸B neutrino production (see Haubold and Gerth 1985). The prediction of this periodicity in the neutrino production rates is unique among all the competing theories that resolve the solar neutrino paradox and is testable by the new generation of solar neutrino detectors.
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Chung, Wanyu. « Three essays in international economics : invoicing currency, exchange rate pass-through and gravity models with trade in intermediate goods ». Thesis, University of Warwick, 2014. http://wrap.warwick.ac.uk/66297/.
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A large proportion of international trade is in intermediate goods. The implications of this empirical regularity, however, have not been exhaustively explored in several aspects. The main objective of the thesis is to fill in the gap by introducing trade in intermediate goods into several strands of literature in international economics. This thesis is a collection of three essays studying the implications of trade in intermediate goods for the degree of exchange rate pass-through (Chapter 2), firms invoicing currency choice (Chapter 3) and the performance of the gravity models (Chapter 4). In Chapter 2 I present a theoretical framework and show that back-and-forth trade between two countries is associated with low degrees of aggregated exchange rate pass-through. In Chapter 3 I focus instead on firm heterogeneity in the dependence on imported inputs. I show theoretically that exporters more dependent on foreign currency-denominated inputs are more likely to price in the foreign currency. I then test the theoretical prediction using an innovative and unique dataset that covers all UK trade transactions with non-EU partners from HM Revenue and Customs (HMRC). Overall the results strongly support the theoretical prediction. Chapter 4 is a theoretical piece of work showing how the underlying trade structure alters the predictions of the gravity models. I relate gravity equations to labour shares of income. Given that these parameters are industry-specific, the results suggest that it is crucial to take them into account when the main research interest lies in sectoral differences in bilateral trade.
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Ateya, Ismail Lukandu. « Precise determination of variable density contrasts, position of contact surfaces and corrections to the possible errors for an intermediate layer in Gravity Inversion Modeling ». 京都大学 (Kyoto University), 2003. http://hdl.handle.net/2433/149081.
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Lampin, Marie Emilie. « Validation d’un score d’alerte et caractérisation des trajectoires de gravité des patients hospitalisés dans les unités de surveillance continue pédiatriques ». Thesis, Lille 2, 2019. http://www.theses.fr/2019LIL2S047.
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Contexte : Les unités de surveillance continue (USC) pédiatriques constituent des structures de soins intermédiaires, entre les services « classiques » de pédiatrie (dits« soins courants ») et les services de réanimation, pour les enfants nécessitant une surveillance continue sans mise en oeuvre de méthode de suppléance. Ces patients sont à haut risque de dégradation et la validation d’un score d’alerte précoce (SAP) dans cette population serait intéressante.Objectifs : 1- Valider un score d’alerte précoce en USC pédiatriques.2- Classifier les malades de ces USC pédiatriques selon leurs caractéristiquesgénérales, leurs affections et les trajectoires de gravité de leur maladie.Méthodes : Etude observationnelle prospective multicentrique régionale dans septUSC pédiatriques françaises incluant tous les enfants consécutifs admis de septembre 2012 à janvier 2014. Validation de trois SAP, recueillis toutes les 8 heures (le Pediatric Advanced Warning Score (PAWS), le Pediatric Early WarningScore (PEWS) et le Bedside Pediatric Early Warning System (Bedside PEWS)) dans la population d’USC en utilisant un modèle linéaire mixte généralisé pourmesures répétées. La cohorte était divisée en échantillon de dérivation (70%) et en échantillon de validation (30%). La discrimination de ces SAP pour la prédiction de l’appel du médecin par l’infirmière en cas de détérioration clinique était mesurée par l’aire sous la courbe ROC. Un modèle mixte linéaire à classes latentes était utilisé pour identifier différentes trajectoires de gravité de ces patients d’USC.Résultats : Un total de 2868 enfants a été inclus pour 14708 observations utilisables pour calculer a posteriori les SAP. La discrimination des trois SAP pour prédire l’appel du médecin était bonne (entre 0,87 et 0,91) sur la cohorte de dérivation et modérée (entre 0,71 et 0,76) sur la cohorte de validation.La défaillance principale à l’origine de l’admission en USC était respiratoire (44%)et l’étiologie infectieuse était la plus fréquente (52%). Les deux diagnostics les plus fréquents étaient l’asthme et la bronchiolite. Dix diagnostics représentaient 58%des patients d’USC. La médiane de durée de séjour était de 1 jour [1-3]. L’analyse en classe latente mettait en évidence différentes trajectoires de gravité : le profil« stable» (60,4%), le profil « amélioration rapide » (6,5%) et le profil« amélioration lente » (33,1%).Conclusion : Les SAP peuvent être utilisés dans les USC pour détecter une détérioration clinique et prédire la nécessité d'une intervention médicale. Trois trajectoires très différentes de gravité ont été identifiées avec une majorité de patients appartenant au profil « stable»Background: Pediatric Intermediate care units (PImCU) are Intermediate care units(ImCU) or high dependency care units (HDC), between regular wards and intensivecare units (ICUs), for children requiring continuous monitoring without active lifesupportingtreatment. These patients are at high risk of deterioration and thevalidation of an early warning score (EWS) in this population would be interesting.Objectives: 1- To validate early warning scores in PImCU2- To classify patients according to their general characteristics, their diagnoses andthe severity trajectories of illness.Methods: Regional multicenter prospective observational study in seven FrenchPImCU including all consecutive children admitted from September 2012 toJanuary 2014. Validation of EWS in PImCU using a general linear mixed modelfor repeated measures. The cohort was divided into derivation (70%) and validation(30%) cohorts. The discrimination to predict physician call by nurse was estimatedby the area under the receiver-operating curve. A latent class linear mixed modelwas used to identify different trajectories of severity of illness of PImCU patients.Results: A total of 2868 children were included for 14708 observations to computea posteriori the EWS. The discrimination of the three EWS for predicting calls tophysicians by nurses was good (range: 0.87–0.91) for the derivation cohort andmoderate (range: 0.71–0.76) for the validation cohort. The primary failure foradmission to PImCU was respiratory (44%) and infectious etiology was the mostcommon (52%). The two most common diagnoses are asthma and bronchiolitis.Ten diagnoses account for 58% of PImCU patients. The median length of stay was1 day [1-3]. The latent class analysis identified different trajectories of severity ofillness: profile "stable" (60.4%), profile "rapid improvement" (6.5%) and profile"slow improvement" (33.1%).Conclusion: SAP can be used in PImCU to detect clinical deterioration and predictthe need for medical intervention. Three very different trajectories of severity wereidentified with a majority of "stable" profile
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Reaume, Jonathan Daniel. « Wave-Cavity Resonator : Experimental Investigation of an Alternative Energy Device ». Thesis, 2015. http://hdl.handle.net/1828/6960.
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A wave cavity resonator (WCR) is investigated to determine the suitability of the
device as an energy harvester in rivers or tidal flows. The WCR consists of coupling
between self-excited oscillations of turbulent flow of water in an open channel along the
opening of a rectangular cavity and the standing gravity wave in the cavity. The device
was investigated experimentally for a range of inflow velocities, cavity opening lengths,
and characteristic depths of the water. Determining appropriate models and empirical
relations for the system over a range of depths allows for accuracy when designing
prototypes and tools for determining the suitability of a particular river or tidal flow as a
potential WCR site. The performance of the system when coupled with a wave
absorber/generator is also evaluated for a range piston strokes in reference to cavity wave
height. Video recording of the oscillating free-surface inside the resonator cavity in
conjunction with free-surface elevation measurements using a capacitive wave gauge
provides representation of the resonant wave modes of the cavity as well as the degree of
the flow-wave coupling in terms of the amplitude and the quality factor of the associated
spectral peak. Moreover, application of digital particle image velocimetry (PIV) provides
insight into the evolution of the vortical structures that form across the cavity opening.
Coherent oscillations were attainable for a wide range of water depths. Variation of the
water depth affected the degree of coupling between the shear layer oscillations and the
gravity wave as well as the three-dimensionality of the flow structure. In terms of the
power investigation, conducted with the addition of a load cell and linear table-driven
piston, the device is likely limited to running low power instrumentation unless it can be
up-scaled. Up-scaling of the system, while requiring additional design considerations, is
not unreasonable; large-scale systems of resonant water waves and the generation of large
scale vortical structures due to tidal or river flows are even observed naturally.Graduate
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reaumejd@uvic.ca
Livres sur le sujet "Gravità intermedia"
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ShackletonCaroline. UP IN THE AIR : OUR FIGHT AGAINST GRAVITY INTERMEDIATE BOOK WITH ONLINE ACCESS. Cambridge University Press, 2014.
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Saha, Prasenjit, et Paul A. Taylor. The Main Sequence of Stars. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198816461.003.0007.
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This chapter introduces the basics of radiative transfer, which is a primary energy-transport mechanism inside stars, and also contributes to keeping stars ‘inflated’ and balanced against gravity. The roles of opacity and cross-sections in scattering photons are described. With the help of some drastic but still insightful approximations, the luminosity of a star can be related to its mass, and its surface temperature to its interior temperature. Not all types of stars are covered with analytical approximations, and only the simplest cases are studied here: the high-mass main sequence stars where radiation-pressure dominates, and the intermediate mass range that includes the Sun, where gas pressure dominates but convection is not yet important.
Chapitres de livres sur le sujet "Gravità intermedia"
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Meyer, I. « Fallbeispiel Neurologie – Myasthenia gravis ». Dans Pflegewissen Intermediate Care, 215–26. Berlin, Heidelberg : Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-49511-7_15.
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Meyer, I. « Fallbeispiel Neurologie – Myasthenia gravis ». Dans Pflegewissen Intermediate Care, 193–203. Berlin, Heidelberg : Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-30001-1_15.
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Fischbach, Ephraim, et Carrick L. Talmadge. « Spin-Dependent Intermediate-Range Forces ». Dans The Search for Non-Newtonian Gravity, 207–12. New York, NY : Springer New York, 1999. http://dx.doi.org/10.1007/978-1-4612-1438-0_7.
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Altarelli, Guido, et Stefano Forte. « Gauge Theories and the Standard Model ». Dans Particle Physics Reference Library, 7–33. Cham : Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-38207-0_2.
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AbstractThis chapter, Chaps. 10.1007/978-3-030-38207-0_3 and 10.1007/978-3-030-38207-0_4 present a self-contained introduction to the Standard Model of fundamental interactions, which describes in the unified framework of gauge quantum field theories all of the fundamental forces of nature but gravity: the strong, weak, and electromagnetic interactions. This set of chapters thus provides both an introduction to the Standard Model, and to quantum field theory at an intermediate level. The union of the three chapters can be taken as a masters’ level course reference, and it requires as a prerequisite an elementary knowledge of quantum field theory, at the level of many introductory textbooks, such as Vol. 1 of Aitchison-Hey, or, at a somewhat more advanced level, Maggiore. The treatment is subdivided into three parts, each corresponding to an individual chapter, with more advanced field theory topics introduced along the way as needed. Specifically, this chapter presents the general structure of the Standard Model, its field content, and symmetry structure. This involves an introduction to non-abelian gauge theories both at the classical and quantum level. Also, it involves a discussion of spontaneous symmetry breaking and the Higgs mechanism, that play a crucial role in the architecture of the Standard Model, and their interplay with the quantization of gauge theories. Chapter 10.1007/978-3-030-38207-0_3 then presents the electroweak sector of the Standard Model. This requires introducing the concepts of CP violation and mixing, and of radiative corrections. Finally, Chap. 10.1007/978-3-030-38207-0_4 presents the strong sector of the theory, which requires a more detailed treatment of renormalization and the renormalization group.
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Richardson, Jeremy. « : Pressure Groups and Parties ». Dans The British Study of Politics in the Twentieth Century. British Academy, 2003. http://dx.doi.org/10.5871/bacad/9780197262948.003.0007.
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The central paradox in reviewing the contribution of British political scientists to the understanding of these intermediary institutions is that both the number of scholars and the output have been considerable, yet the international impact has been relatively modest. Two explanations seem plausible. First, with a few notable exceptions, the centre of gravity of these studies has coincided with the centre of gravity of British political science as a whole – it is largely atheoretical in its research style. A second possible explanation is that studies in these fields have tended to focus on activities (of groups and social movements) or on office-holding (parties) and have been much less interested in power as a concept. Relatively little is known about the effects that this activity has on outcomes in terms of public policy or the distribution of power in society.
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Ramírez-Ronda, Carlos H., et Carlos R. Ramírez-Ramírez. « Corynebacteria ». Dans Schlossberg's Clinical Infectious Disease, sous la direction de Cheston B. Cunha, 888–94. Oxford University Press, 2021. http://dx.doi.org/10.1093/med/9780190888367.003.0131.
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This chapter investigates Diphtheria as an acute, infectious, preventable, and sometimes fatal disease caused by Corynebacterium diphtheriae. It highlights the infection caused by Diphtheria, which is usually localized to the upper part of the respiratory tract or the skin and gives rise to local and systemic signs. It explains that the systemic signs of infections are the result of a toxin produced by the microorganisms multiplying at the site of infection, which particularly affect the heart, the peripheral nerves, or the kidneys. This chapter describes the worldwide distribution of Diphtheria into four biotypes: gravis, intermedius, mitis, and belfanti. It mentions epidemic and endemic diphtheria that occur in temperate climates and under poor socioeconomic conditions, where crowding is common and where many persons are either not immunized or inadequately immunized.
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Haroutounian, Joanne. « The Flame : Teenage Years ». Dans Kindling the Spark. Oxford University Press, 2002. http://dx.doi.org/10.1093/oso/9780195129489.003.0022.
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Close to a dozen years have gone by and we find ourselves seated on folding chairs enjoying the final recital of a private studio of talented piano students. Each year there are a few new eager faces as the younger students deftly work through pieces that seem very complex for such little fingers to play so quickly. We notice the students who have been seasoned through training, now in those tenuous intermediate years. Their intense desire for precision shows maturing musical ideas, but often arrives at awkward adolescence when being on stage has an added gravity of meaning. We search for the advanced teenagers—those students we have seen truly blossom through the long process of talent development. Numbers have dwindled in this studio. One has decided to move out of state and is now studying at a conservatory. Another has decided to concentrate efforts on the oboe, begun in elementary school band, with time restraints easing piano lessons out of her schedule. Academic and parental pressures have caused last year’s shining star, a junior seeking an Ivy League college education, to quit as well. There remains one teenager who ends the program with a flourish, receiving many hugs from young admirers and awards galore following the program. This is our tiny, eager student from the front steps. A senior, having completed a full twelve years of instruction with many competitions and solo recitals under his belt, he bids farewell to this comfortable, nurturing studio. He enters college as a math major. Many private teachers, parents, and music students may recognize this scene as a very realistic portrayal of possibilities in musical talent development. The first years of training are “romance,” with parents aglow when hearing their talented youngster perform with such confidence and flair. The middle years consist of flux and flow, a phase when students search for the “whys” and “hows” beneath the notes that were so easily played in prior years. Musical training now presents persistent challenges. Late-starters may speed into these years with determination. Others may begin a second instrument or composition classes to broaden musical experiences.
Actes de conférences sur le sujet "Gravità intermedia"
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Shu, Y., B. Q. Li et B. R. Ramaprian. « Natural Convection in Modulated Thermal Gradients and Gravity : Numerical Simulation and Experimental Measurements ». Dans ASME 2003 Heat Transfer Summer Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/ht2003-47299.
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This paper presents an investigation on natural convection in a cavity with an imposed modulated thermal gradient or modulated gravity forces. Numerical computations are presented, which are based on the finite element solution of transient Navier-Stokes and energy balance equations, along with appropriate boundary conditions or time-varying gravity forces. To verify the numerical predictions, an experimental system is setup where wall temperatures are oscillated to produce modulated temperature gradients and the velocity fields are measured by a laser-based Particle Image Velocimetry (PIV) system. Computed results compare well with experimental measurements for various conditions. With the mathematical model, so verified by experimental measurements, extensive numerical simulations are carried out to study the effects of modulation frequency and Prandtl numbers on the fluid flow. Results show the strong nonlinear interaction in the intermediate range of modulation frequency. It is also found that with a small Prandtl number typical of molten metals and semiconductor melts, modulated gravity and thermal gradients produce almost the same flow field both in structure and in magnitude.
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Gupta, Subodh. « Physics-Based 3-Phase Relative Permeability for Gas-Liquid Counter-Current Flow ». Dans SPE Annual Technical Conference and Exhibition. SPE, 2022. http://dx.doi.org/10.2118/210445-ms.
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Abstract The objective of this paper is to present a fundamentals-based, consistent with observation, three-phase relative permeability model to describe flow more accurately in countercurrent movement of gas and liquids situation. While most flooding operations have both gas and liquids flowing in the same direction, in gravity dominated processes such as steam assisted gravity drainage (SAGD) or CO2 storage in water saturated reservoirs, often due to density difference the gases rise above and liquids flow down. This gives rise to a counter-current flow situation. It has been documented by a few researchers including Adebayo et al. (2017) and Prats et al. (2008). At the gas-liquid interface, the shear forces act to oppose movement of gas and liquids resulting in a slowdown in the flow of both. This slow-down or reduced flow is not captured in standard relative permeability curves which are typically generated using co-current flows. In the current work, the approach adopted by Gupta (2021) for a mechanistic 3-phase flow model is used to develop relative permeability expressions for gravity-incorporated flow. To do this, three-phase core-annular laminar flow expressions are first developed in a single thin tube, then these flow expressions are aggregated for the entire pore volume represented by a bundle of tubes with varying tube sizes mimicking pore-size distribution. An irreducible water saturation, when water is the wetting phase, is also assumed. The relative permeabilities obtained with counter-current flow considerations are compared with the ones presented in Gupta (2021) for co-current flow to highlight the difference. Additionally, the impact of these modified rel. perms is shown with an example SAGD problem resulting in a slower and more realistic growth of the steam chamber. Similar to the observation of Gupta (2021) this mechanistic model also indicates a natural dependence of rel. perms of the intermediate phase on temperature, which in literature has been a subject of much debate. The novelty of the work is in development of a three-phase relative permeability model which takes into account gas-liquid countercurrent movement in porous media based on fundamentals of flow in fine capillaries. The significance of the work includes, aside from predicting results more in line with expectations in gravity-dominated processes, an explanation of temperature dependent relative Gupermeabilities of the intermediate phases. Also, unlike Stone-II method, it predicts a more realistic time dependent residual oleic-phase saturation for gravity drainage recovery methods.
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Nishioji, Takashi, Taichi Kato, Yutaka Fukuhara, Tatsuya Hazuku, Tomoji Takamasa et Takashi Hibiki. « Effect of Gravity on Axial Development of Phase Distribution Patterns in Bubbly Two-Phase Flow ». Dans 17th International Conference on Nuclear Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/icone17-75232.
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The axial development of the void fraction profile, interfacial area concentration and Sauter mean bubble diameter of adiabatic nitrogen-water bubbly flows in a 9 mm-diameter pipe were measured using stereo image processing in normal and microgravity conditions. The effect of gravity and flow conditions on the radial distribution of bubbles and the axial development of the two-phase flow parameter is discussed in detail based on the obtained data. By taking into account normalized parameters based on void peak fraction and void peak intensity in the pipe cross-section, the phase distribution patterns were classified into three types: a wall peak, a core peak and an intermediate peak. Phase distribution pattern maps are presented for vertical upward bubbly flows in normal and microgravity conditions.
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Benito, Diego, Jeff Dixon et Paul Metherell. « 3D Thermo-Mechanical Modelling Method to Predict Compressor Local Tip Running Clearances ». Dans ASME Turbo Expo 2008 : Power for Land, Sea, and Air. ASMEDC, 2008. http://dx.doi.org/10.1115/gt2008-50780.
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This paper presents a 3D thermo-mechanical modelling method to calculate compressor local tip running clearances. The method requires a solid geometry representation of the compressor casings and main engine structures, including local geometry features such as thrust lugs, gearbox, sump, offtake bosses and struts. The finite element model is capable of predicting asymmetric temperature and displacement distributions for transient and steady-state conditions as a result of thermal, pressure and mechanical loads (e.g. thrust, gas torques, gravity, gusts, etc). This methodology has been applied to calculate local tip clearances on the intermediate pressure compressor of a civil aero-engine. The results from the 3D solid model have been compared to those obtained with more conventional analysis tools (i.e. 2D axisymmetric thermo-mechanical models and 3D isothermal shell and beam models) in order to build confidence in the new methodology. Local tip running clearances were measured on the intermediate pressure compressor by means of capacitance probes. Measured local closures for a typical square cycle including a low power idle phase and high power max take-off phase have been compared to predicted local closures to establish the validity of the new methodology.
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Pang, Liping, Shangmin Li, Hu Yuan et Liqiang Duan. « Study on Gas-Liquid Two-Phase Flow Distribution Inside a Flute Header ». Dans ASME 2020 Power Conference collocated with the 2020 International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/power2020-16710.
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Abstract When the supercritical boiler is working at low load during flexible operation, the uneven distribution of the gas-liquid flow at the intermediate header may affect the safety of the water-cooled wall at the vertical parallel panels. In order to improve the uniformity of gas-liquid flow distribution in the water-cooled wall of intermediate header and study the internal flow mechanism, a flute inside the header is applied with parallel vertical parallel channels and experiments under different operating conditions are conducted to verify the effectiveness of this geometrical structure. The flow pattern in the experiment belongs to stratified and wavy flow. Computational fluid dynamic (CFD) simulation is conducted in order to investigate two-phase flow distribution behavior inside a flute header. It was found that the radial gas phase distribution in the flute tube shows a symmetrical relationship, and there are two vortexes in opposite directions. With the increasing distance from the inlet, the uniformity of the gas phase distribution becomes even. The gravity is greater than the drag force, which has effect on the two-phase flow distribution. The gas phase velocity has been improved inside flute section and liquid phase flow has more even flow distribution along annular section. It makes liquid phase sent to far end of flute header. That benefits two-phase flow distribution along 10 parallel channels equally.
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Li, Ye, et Ragha Rapthadu. « Bending-Additive-Machining Hybrid Manufacturing of Sheet Metal Structures ». Dans ASME 2017 12th International Manufacturing Science and Engineering Conference collocated with the JSME/ASME 2017 6th International Conference on Materials and Processing. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/msec2017-3062.
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The ever-increasing industry innovation demands a paradigm of manufacturing process that is capable of accomplishing multiple tasks on a single component. Majority of structural parts require bending of metal sheets with high degree of accuracy. In many applications bent parts with additional features are sought out for various special purposes. Clearly there is a need calling for the integration of different manufacturing processes to reach a synergistic effect [4, 5]. Traditionally a combination of additive manufacturing and machining is used to alleviate the constraints set forth by machining alone. However this hybrid approach is still constrained by both the limited cutter accessibility and gravity-imposed deposition direction. This paper presents a new Hybrid Manufacturing configuration by combining bending, deposition and machining processes. The major advantage of this new approach hinges on the deliberate use of bending process by providing additional accessibility that is not available on traditional additive – machining setup. Essentially the accessibility issue is overcome by introducing an intermediate bending step so that both metal deposition and removal can be conducted in the process-required orientation. As bending is part of this new hybrid process, springback is also inherent to this new hybrid manufacturing approach. This research incorporates the consideration of both springback compensation and cold hardening effect in the selection of intermediate bending step. Examples are also provided to show the efficacy of this new hybrid manufacturing approach.
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Yan, Xia, Xuedong Ou, Mingqiang Lin, Jian Mou, Shaolei Sun, Chunyun Chi, Chunqing Zhao et Qin Zhou. « The Core Design Modifications for Stirling Thermal-Electric Integrated Micro Reactor ». Dans 2022 29th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/icone29-93465.
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Abstract Currently a two-step designing method of sequential neutronic physics and Stirling physical analysis was used for a Miniature Integrated nuclear Reactor design with gravity independent Autonomous Circulation (ACMIR). It was proposed in this article to optimize the intermediate/transitive variables of dead volume and heat exchange area/dead volume ratio as much as possible in the first step so that the system objectives in the second step can be better achieved. The ACMIR core was modified from using rod typed fuels to using plate typed fuels, making use of the plated core’s advantages of easy compression of coolant flow channel while maintaining large heat transfer area. As applied to a 40kWt cooperative dual Stirling power system design of ACMIR, the output power and efficiency index of the system had been significantly improved from 981W to 6395W (each Stirling), with efficiency from 7.4% to 26.6%.
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Shi, Yue, et Kishore Mohanty. « Surfactant Enhanced Oil Recovery from Tight Carbonates : Core-Scale Experiments to Reservoir-Scale Modeling ». Dans SPE Improved Oil Recovery Conference. SPE, 2022. http://dx.doi.org/10.2118/209418-ms.
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Abstract Most carbonate reservoirs are oil-wet/mixed-wet and heterogenous at multiple scales. Majority of the injected water flows through the high permeability regions/fractures and bypass the oil in the matrix due the high negative capillary pressure (Pc). To enhance oil recovery from such reservoirs, the sign of the Pc should be changed by wettability alteration (WA) or the Pc should be reduced by lowering interfacial tension (IFT). In this study, surfactants which can either alter wettability or develop ultra-low IFT were identified through laboratory measurements for the target carbonate reservoir. The performance of these two types of surfactants was systematically evaluated at the core scale and scaled-up to the reservoir scale. A reservoir-scale model was developed to simulate injection-soak-production (ISP) tests and evaluate performance of the selected surfactants at the field scale. Experiments showed that quaternary ammonium cationic surfactants have excellent WA ability, while a series of propoxy sulfate anionic surfactants showed intermediate WA and ultra-low IFT. Spontaneous imbibition tests showed that WA surfactants have fast initial oil production, while ultra-low IFT surfactants has low initial oil rate but higher final oil recovery, which was validated by mechanistic simulation. Low IFT results in low Pc and slow imbibition, but also triggers gravity-driven drainage. For ultra-low IFT system, gravity drainage is more dominant than WA, and Pc-alteration is less important than relative permeability (Kr) alteration. As reservoir thickness increases, Kr-alteration is more important than Pc-alteration. Gravity drainage is expected to be scaled up by length of matrix (L), while Pc-driven imbibition is scaled by L2. Field-scale simulation showed that low-IFT surfactant has better injectivity than WA surfactant during injection phase. In soaking phase, spontaneous imbibition by WA surfactant is much more significant than that by low-IFT surfactant. In production phase, post-waterflood achieved higher oil recovery from low-IFT surfactant treated matrix due to its low residual oil saturation and high oil relative permeability.
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Takahira, Hiroyuki, Tomonori Horiuchi et Sanjoy Banerjee. « An Improved Three-Dimensional Level Set Method for Gas-Liquid Two-Phase Flows (Keynote) ». Dans ASME/JSME 2003 4th Joint Fluids Summer Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/fedsm2003-45389.
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For the present study, we developed a three-dimensional numerical method based on the level set method that is applicable to two-phase systems with high-density ratio. The present solver for the Navier-Stokes equations was based on the projection method with a non-staggered grid. We improved the treatment of the convection terms and the interpolation method that was used to obtain the intermediate volume flux defined on the cell faces. We also improved the solver for the pressure Poisson equations and the reinitialization procedure of the level set function. It was shown that the present solver worked very well even for a density ratio of the two fluids of 1:1000. We simulated the coalescence of two rising bubbles under gravity, and a gas bubble bursting at a free surface to evaluate mass conservation for the present method. It was also shown that the volume conservation (i.e., mass conservation) of bubbles was very good even after bubble coalescence.
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Knight, Tristan, Axel Rousse, Clémence Allietta et Benjamin Bérat. « TOLOSAT project : Gravimetry and communication ». Dans Symposium on Space Educational Activities (SSAE). Universitat Politècnica de Catalunya, 2022. http://dx.doi.org/10.5821/conference-9788419184405.009.
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The use of Constellations for weather science, security and disaster monitoring is a major challenge for space application services. Satellite to satellite communication using existing constellations has not been extensively explored yet. It can improve the communication times for small-satellite missions which have limited access to ground stations. Thus, a mission to demonstrate the feasibility of this link is required. Another element of interest in space application is Earth Observation, especially in the context of Climate Change. Gravimetry allows an understanding of mass transport in the Earth System through the remote sensing of the time variation of the Earth gravity field. CubeSats are low-cost small-scale and hence lower risk solutions to Earth Observation missions. University CubeSats have shown their success in demonstration and scientific missions, and have a great potential in providing students with practice and application on real space systems. In this context, the student associations ASTRE and SUPAERO CubeSat Club have joined in a CubeSat program called TOLOSAT, with the hope of demonstrating such technologies. Gathering 70 students from Toulouse, the team was split into subsystems in accordance with the concurrent engineering principles. The work performed followed recommendations from experts from the French National Centre for Space Studies (CNES) and the industry. The TOLOSAT payloads have to test and demonstrate new means of measuring gravity and addressing communication issues. Firstly, for the gravimetry mission, our approach relies solely on GNSS to compute the gravity field, avoiding expensive gravimeters. For the communication mission: the Iridium constellation will be used as an intermediate between the CubeSat and the ground station. Off-the-shelf components such as patch antennas are planned to prove their efficiency in orbit. This would improve the coverage and the communication window. The preliminary design was completed. TOLOSAT was designed as a 3-unit nanosatellite, on a 97.4° inclined, 500km high orbit. Margins were also ensured to allow a third payload to be defined in the future, that will be used for finance and partnerships. Detailed designs are still required, but the educational purposes have been fulfilled, in terms of discovery of the development of space missions as well as in the teamwork culture. The team is now moving on to a new phase, dedicated to a more detailed conception with an on-going focus on the introduction to students to technical - but not only - fields of knowledge applied to space systems