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Littérature scientifique sur le sujet « Pulsatoria »

Auteur : Grafiati

Publié le 9 mars 2023

Mis à jour le 10 mars 2023

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Articles de revues sur le sujet "Pulsatoria"

Fryč, J., R. Kukla et J. Los. « Possible use of vacuum controlled pulsators for sheep milking machines ». Research in Agricultural Engineering 50, No. 1 (8 février 2012) : 23–27. http://dx.doi.org/10.17221/4922-rae.

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Comparison measurements and evaluation of the suitability of three pulsators for sheep milking machines were carried out, i.e. a prototype made by the manufacturer of the milking parlour of the pulsator ratio 50% (50:50) and two hydraulic pulsators of the Danish manufacturer S.A. Christensen (SAC), models Unipuls-2 of the pulsator ratios 50% (50:50) and 60% (60:40). The specified pulsation rate was 2.5/s(150/min). It was found that the pulsator prototype made by the milking parlour manufacturer slowly passed air, whereby the vacuum in pulsation chambers did not attain the maximum value. Fig. 2 illustrates the operation of this pulsator. Both SAC pulsators had better parameters and their pulsograms are plotted in Figs. 3 and 4. Also the measurements of a liner deformation in dependence on the vacuum in the teatcup pulsation chamber were made based on which the moment of a real liner opening, i.e. at the vacuum of 35 kPa was determined. The results obtained by the experiments carried out can be summed up as follows: As the change in pulsation rate does not affect the time of transition phases “a” and “c”, the intervals “b” and “d” are shorter if the pulsation rate is increased. Interval “b”, i.e. a full liner opening, shortens with the rising rate and extends with the increased value of the pulsator ratio. For this reason higher pulsator ratios should be used at very high pulsation rates. The teatcup operation depends on the physical-mechanical properties of the liner used. On the milking unit measured considerable differences in time take place between the interval “b” and the liner full opening due to a relatively high resistance power of the liner to deformation. The pulsator prototype designed by the milking parlour producer revealed as fully unsuitable based on its pulsogram. As far as the time of the liner opening is concerned, its parameters were worse than on both SAC pulsators, however, we cannot indicate it as unsuitable.

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Burssens, S., D. M. Bowman, C. Aerts, M. G. Pedersen, E. Moravveji et B. Buysschaert. « New β Cep pulsators discovered with K2 space photometry ». Monthly Notices of the Royal Astronomical Society 489, n^o 1 (16 août 2019) : 1304–20. http://dx.doi.org/10.1093/mnras/stz2165.

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Abstract We present the discovery of three new β Cep pulsators, three new pulsators with frequency groupings, and frequency patterns in a B3Ib star, all of which show pulsations with frequencies as high as about 17 d−1, with K2 space mission photometry. Based on a Fourier analysis and iterative pre-whitening, we present a classification and evaluate the potential for asteroseismic modelling. We include the lists of pulsation frequencies for three new β Cep pulsators, CD-28 12286, CD-27 10876, LS 3978, and additional pulsation mode frequencies for the known β Cep pulsator HD 164741. In addition, we characterize the regular frequency spacing found in the new pulsator HD 169173, and discuss its origin. We place the newly discovered variables in a colour–magnitude diagram using parallaxes from GaiaDR2 (second data release), showcasing their approximate location in the massive star domain. The identified frequency lists of these multiperiodic pulsators are a good starting point for future forward seismic modelling, after identification of at least one pulsation frequency from high-resolution time-series spectroscopy and/or multicolour photometry.

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Salazar-Vallejo, Sergio I., Patrick Gillet et Victor Surugiu. « How false is Nereis falsa (Annelida, Phyllodocida, Nereididae) ? » Revista de Biología Tropical 65, n^o 3 (23 mars 2017) : 847. http://dx.doi.org/10.15517/rbt.v65i3.26635.

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There are many taxonomic problems in polychaete species names and solving confusing or inadequate taxonomic procedures is both time-demanding and extremely important. Our objective in this contribution was to analyse what is the current taxonomic situation for Nereis falsa de Quatrefages, 1866; it was based upon Nereis pulsatoria? Rathke, 1837 from the Black Sea, and it is currently regarded as having a very wide distribution. The species has been collected from different benthic substrates and even can be found on floating objects or marine turtles. Nereis falsa has been recorded from the Mediterranean Sea, the Eastern Atlantic along Africa, the Western Atlantic (Gulf of Mexico, Caribbean Sea, Brazil), and the Indian Ocean. However, despite the fact N. falsa was proposed as a species from the Black Sea, it has not yet been found there. How can we explain that a species is able to attain a very wide distribution and yet be missing from its type locality? After a careful study of previous publications and with our understanding of the systematics of nereidid polychaetes, we clarify the current situation by examining several related species and pointed out some nomenclatural issues. Our analysis indicates there is more than one species included under the same name, and in this contribution we propose some means to promote discussion and actions, and suggest some basic research for solving this issue.

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Westwood, J. O. « XV. Observations upon the structural Character of the Death Watch (Atropos pulsatoria), with Description of a new British Genus in the Family to which it belongs ». Transactions of the Royal Entomological Society of London 4, n^o 1 (24 avril 2009) : 71–72. http://dx.doi.org/10.1111/j.1365-2311.1845.tb01339.x.

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Yatsunskyi, Petro. « THE RESULTS OF RESEARCH PNEUMATIC ELECTROMAGNETIC PULSATOR COMBINED WITH COLLECTOR ». Mokslas - Lietuvos ateitis 14 (1 février 2022) : 1–4. http://dx.doi.org/10.3846/mla.2022.15162.

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This article demonstrates the results of experimental research one of the pulsators. Its main difference from others is a pneumatic electromagnetic pulsator in combination with a collector. Therefore, this article describes in detail the process of studying the pulsator. The planned experiment was carried out on by Factorial experiments with multiple factors. The influence of factors (the ripple frequency n, the milk ejection q and the ratio between strokes t/T) on the vacuum pressure in the inter wall chamber of teat cups was studied. The regression equation of the dependence response criterion on factors is modeled. This dependence is demonstrated graphically. Also there is a contour graph which is for more detailed information.

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Kurtz, D. W., G. Handler, S. A. Rappaport, H. Saio, J. Fuller, T. Jacobs, A. Schmitt et al. « The single-sided pulsator CO Camelopardalis ». Monthly Notices of the Royal Astronomical Society 494, n^o 4 (13 avril 2020) : 5118–33. http://dx.doi.org/10.1093/mnras/staa989.

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ABSTRACT CO Cam (TIC 160268882) is the second ‘single-sided pulsator’ to be discovered. These are stars where one hemisphere pulsates with a significantly higher amplitude than the other side of the star. CO Cam is a binary star comprised of an Am δ Sct primary star with Teff = 7070 ± 150 K, and a spectroscopically undetected G main-sequence secondary star. The dominant pulsating side of the primary star is centred on the L1 point. We have modelled the spectral energy distribution combined with radial velocities, and independently the TESS light curve combined with radial velocities. Both of these give excellent agreement and robust system parameters for both stars. The δ Sct star is an oblique pulsator with at least four low radial overtone (probably) f modes with the pulsation axis coinciding with the tidal axis of the star, the line of apsides. Preliminary theoretical modelling indicates that the modes must produce much larger flux perturbations near the L1 point, although this is difficult to understand because the pulsating star does not come near to filling its Roche lobe. More detailed models of distorted pulsating stars should be developed. These newly discovered single-sided pulsators offer new opportunities for astrophysical inference from stars that are oblique pulsators in close binary stars.

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Lashlee, Taylor, Adrienne DiFoggio, Pablo Jarrin-Yepez, Heather Schwartz, Margarita Colburn, Andrew Cushing et Tulio Prado. « Breeding soundness examination in a clouded leopard ». Clinical Theriogenology 14, n^o 2 (1 juin 2022) : 98–101. http://dx.doi.org/10.58292/ct.v14.9284.

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A 3-year male clouded leopard was presented to the University of Tennessee College of Veterinary Medicine Theriogenology servicesfor a breeding soundness examination. On physical examination, the left testis felt abnormally small. On ultrasonography,no abnormalities were observed; testis and prostate were of normal size. Semen was collected with a pulsator electroejaculatorand a ram electroejaculator probe (commonly used to collect semen in small ruminants). The purpose of using this electroejaculatorand probe was to determine if they could be used to collect semen from a clouded leopard. Using manual settings with thisdevice we collected ~ 0.2 - 0.3 ml of semen. Motility and morphology of sperm were acceptable. We concluded that the PulsatorIV electroejaculator and ram probe can be used to collect semen as part of breeding soundness evaluation in a clouded leopard.

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Byrne, Conor M., et C. Simon Jeffery. « Pulsation in faint blue stars ». Monthly Notices of the Royal Astronomical Society 492, n^o 1 (11 décembre 2019) : 232–44. http://dx.doi.org/10.1093/mnras/stz3486.

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ABSTRACT Following the discovery of blue large-amplitude pulsators (BLAPs) by the OGLE survey, additional hot, high-amplitude pulsating stars have been discovered by the Zwicky Transient Facility. It has been proposed that all of these objects are low-mass pre-white dwarfs and that their pulsations are driven by the opacity of iron-group elements. With this expanded population of pulsating objects, it was decided to compute a sequence of post-common-envelope stellar models using the mesa stellar evolution code and to examine the pulsation properties of low-mass pre-white dwarfs using non-adiabatic analysis with the gyre stellar oscillation code. By including the effects of atomic diffusion and radiative levitation, it is shown that a large region of instability exists from effective temperatures of 30 000 K up to temperatures of at least 50 000 K and at a wide range of surface gravities. This encompasses both groups of pulsator observed so far, and confirms that the driving mechanism is through iron group element opacity. We make some conservative estimates about the range of periods, masses, temperatures, and gravities in which further such pulsators might be observed.

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Karczmarek, P. « Contamination of RR Lyrae stars from Binary Evolution Pulsators ». Advances in Astronomy and Space Physics 5, n^o 1 (2015) : 24–28. http://dx.doi.org/10.17721/2227-1481.5.24-28.

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A Binary Evolution Pulsator (BEP) is a low-mass (0.26 𝔐☉) member of a binary system, which pulsates as a result of a former mass transfer to its companion. The BEP mimics RR Lyrae-type pulsations, but has completely different internal structure and evolution history. Although there is only one known BEP (OGLE-BLG-RRLYR-02792), it has been estimated that approximately 0.2% of objects classified as RR Lyrae stars can be undetected Binary Evolution Pulsators. In the present work, this contamination value is re-evaluated using the population synthesis method. The output falls inside a range of values dependent on tuning the parameters in the StarTrack code, and varies from 0.06% to 0.43%.

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Gaulme, Patrick, et Joyce A. Guzik. « Systematic search for stellar pulsators in the eclipsing binaries observed by Kepler ». Astronomy & ; Astrophysics 630 (27 septembre 2019) : A106. http://dx.doi.org/10.1051/0004-6361/201935821.

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Eclipsing binaries (EBs) are unique targets for measuring precise stellar properties and can be used to constrain stellar evolution models. In particular, it is possible to measure masses and radii of both components of a double-lined spectroscopic EB at the percent level. Since the advent of high-precision photometric space missions (MOST, CoRoT, Kepler, BRITE, TESS), the use of stellar pulsation properties to infer stellar interiors and dynamics constitutes a revolution for studies of low-mass stars. The Kepler mission has led to the discovery of thousands of classical pulsators such as δ Scuti and solar-like oscillators (main sequence and evolved), but also almost 3000 EBs with orbital periods shorter than 1100 days. We report the first systematic search for stellar pulsators in the entire Kepler EB catalog. The focus is mainly aimed at discovering δ Scuti, γ Doradus, red giant, and tidally excited pulsators. We developed a data inspection tool (DIT) that automatically produces a series of plots from the Kepler light curves that allows us to visually identify whether stellar oscillations are present in a given time series. We applied the DIT to the whole Kepler EB database and identified 303 systems whose light curves display oscillations, including 163 new discoveries. A total of 149 stars are flagged as δ Scuti (100 from this paper), 115 as γ Doradus (69 new), 85 as red giants (27 new), and 59 as tidally excited oscillators (29 new). There is some overlap among these groups, as some display several types of oscillations. Despite the likelihood that many of these systems are false positives, for example, when an EB light curve is blended with a pulsator, this catalog gathers a vast sample of systems that are valuable for a better understanding of stellar evolution.

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Thèses sur le sujet "Pulsatoria"

CASATI, ANNA. « LA PRESSIONE PULSATORIA NELLA POPOLAZIONE GENERALE : STUDIO DELLA DISTRIBUZIONE DELLA VARIABILE, DELLA SUA CORRELAZIONE CON I FATTORI DI RISCHIO CARDIOVASCOLARE E SUO IMPATTO PROGNOSTICO A LUNGO TERMINE ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2017. http://hdl.handle.net/10281/180697.

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Background: i valori espressi nelle misurazioni della pressione arteriosa derivano dall’interazione di due componenti, una statica rappresentata dalla pressione arteriosa media e una dinamica rappresentata dalla pressione pulsatoria (PP). Alcuni studi hanno posto attenzione alla componente pulsatoria della pressione arteriosa, calcolata come differenza tra pressione arteriosa sistolica e diastolica, valutando l’associazione tra PP e successiva occorrenza di eventi cardiovascolari. Tuttavia la maggioranza di questi studi sono stati effettuati su popolazioni selezionate in base a diversi parametri clinici. Scopo dello studio: lo studio si propone di indagare l’impatto della PP sugli eventi cardiovascolari (CV) e sulla mortalità totale in un campione di soggetti rappresentativo della popolazione generale del nord d’Italia - area Brianza. Endpoint secondari dello studio sono stati la valutazione dell’impatto della PP sullo sviluppo di nuova ipertrofia e di nuova ipertensione. Metodi e risultati: il campione di popolazione che consta di 3200 soggetti è stato casualmente selezionato dai registri comunali della città di Monza usando i criteri MONICA-OMS, in modo da essere rappresentativo della sua popolazione generale dai 25 ai 74 anni di età stratificato per sesso e decadi di età. La percentuale di partecipazione è stata del 64%. Alla randomizzazione ogni soggetto è stato sottoposto ad accurata anamnesi, soprattutto in relazione ai fattori di rischio e alla sua storia cardiovascolare, ad esame obiettivo con rilevazione di peso altezza BMI, misurazione clinica, domiciliare ed ambulatoria della pressione arteriosa, prelievo ematico per la valutazione di glicemia, profilo lipidico, creatininemia, uricemia. E’stata inoltre eseguita un’ecocardiografia per la misurazione degli spessori parietali del ventricolo sinistro e il calcolo della massa ventricolare sinistra secondo la formula di Devereux e in accordo con le più recenti linee guida. Le stesse misurazioni sono state effettuate dopo un follow-up complessivo di 10 anni; per un periodo di 12 anni sono state raccolte le cause di morte dei soggetti deceduti e sono state raccolte le diagnosi dei ricoveri ospedalieri identificandone quelle di natura cardiovascolare, validate attraverso l’analisi diretta della cartella clinica secondo procedure standardizzate. L’età media della coorte era 50,9 e il 50,5% erano uomini. Dopo aggiustamento per età, sesso e corrispondente pressione media, PP Office, PP 24 ore, daytime e nightime risultano associate all’incidenza di eventi cardiovascolari ma non alla mortalità totale. In seguito ad aggiustamento più esteso per colesterolo, glicemia, BMI, pregresso evento cardiovascolare, farmaci antipertensivi e fumo si conferma il valore predittivo di PP Office, PP 24 ore e daytime. Nessuna delle misurazioni delle PP è risultata predittiva di sviluppo di ipertrofia ventricolare sinistra e di insorgenza di ipertensione arteriosa ad eccezione della Home PP che è risultata marginalmente significativa riguardo all’insorgenza di ipertensione. Conclusione: i risultati del nostro studio dimostrano che la pulse pressure basata sulla misurazione clinica e ambulatoria è significativamente correlata al rischio di eventi cardiovascolari.
Background: pulse pressure (PP) calculated as the difference between systolic and diastolic blood pressure, represents dynamic component of arterial blood pressure. Some studies have focused on pulsation component of blood pressure, assessing the association between PP and occurrence of cardiovascular (CV) events. However, most of these studies were performed on selected populations based on several clinical parameters. Aim: the aim of this study was to investigate whether PP is associated with major adverse cardiovascular outcome and total mortality in a sample of subjects representative of general population in Northern Italy - Brianza area. Secondary endpoints of the study were assessing the impact of PP on developing new hypertrophy and new hypertension. Methods and results: A cohort of 3200 subjects were randomly selected from the general population of Monza (Italy) aged 25 to 74 years, stratified for sex and decades of age. The percentage of participation was 64%. Each subject underwent medical history, especially in relation to cardiovascular risk factors; office, home and 24-hour ambulatory blood pressure measurement. Anthropometric variables like weight height and BMI, serum cholesterol, blood glucose and echocardiographic parameters were also measured. Cut points for left ventricular hypertrophy were derived from current echocardiographic guidelines. Repetition of all measurements after 10 years allowed to evaluate also the risk of developing of office and out-of-office hypertension and echocardiographic left ventricular hypertrophy. CV events and all-cause mortality were evaluated over a mean follow-up of 12 years. The average age of the cohort was 50.9 and 50.5% were men. After adjusting for age, sex and corresponding mean pressure, Office PP, 24 hours, daytime and nighttime PP are associated with the incidence of CV events but not to total mortality. After more extensive adjustment for cholesterol, blood glucose, BMI, previous event cardiovascular, drugs for hypertension and smoking, remains the predictive value of Office PP, 24 hours and daytime PP. None of the measurements of PP was found to be predictive of the development of left ventricular hypertrophy and of arterial hypertension except Home PP that was marginally significant with respect to the onset of hypertension. Conclusion: The results of our study show that the PP based on clinical and 24-h ambulatory measurement is significantly correlated to risk of CV events.

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Suard, Sylvain. « Propagation pulsatoire des flammes de brouillard ». Laboratoire de modélisation et simulation numérique en mécanique et génie des procédés (Marseille), 2004. http://www.theses.fr/2004AIX22100.

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Giuliani, Fabrice. « Étude du comportement d'un système d'injection de turbomachine en régime pulsatoire forcé ». Toulouse, ENSAE, 2002. http://www.theses.fr/2002ESAE0007.

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Les instabilités de combustion apparaissant dans les systèmes aérobies de type turbomachine résultent d'un couplage aéro-thermo-acoustique et provoquent une usure accrue des pièces constituantes du foyer. Dans le contexte de la compréhension physique des phénomènes de couplage impliqués dans l'apparition, le maintien voire l'encouragement de ces instabilités de combustion, on analyse l'incidence d'une injection instationnaire de carburant sur le processus de combustion. Une installation expérimentale a été conçue dans ce but à l'ONERA Centre de Toulouse. La modulation générée par la pression acoustique sur l'injection est modélisée en pulsant à volonté chaque débit (gaz et liquide) en amont d'un injecteur de type aérodynamique, ceci au moyen d'actionneurs. Les expériences sont réalisées en jet libre aux conditions standards pour une caractérisation du brouillard en non-réactif, et en milieu confiné à une température de 500 K pour les essais en combustion. Ce travail de thèse met d'abord en place le contexte industriel qui justifie le programme d'essais réalisés. Ensuite l'aspect technique est abordé : le banc est décrit en détail, ainsi que les techniques de mesures conditionnées afin de discerner diverses quantités cycliques. Enfin, la caractérisation du brouillard injecté en régime pulsatoire forcé est réalisé, en non-réactif et en combustion. Les résultats mettent en avant l'importance d'une modulation du débit d'air à l'injection, et de ses effets sur le champ aérodynamique de la chambre et sur le transport du mélange air/carburant fortement lié au nombre de Stokes des gouttes.

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Andriamihafy, Herison. « Débitmétrie par diaphragme en écoulement pulsatoire sources d'erreurs et corrections, approche expérimentale et modélisation ». Grenoble : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb375937341.

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Andriamihafy, Hérison. « Débitmétrie par diaphragme en écoulement pulsatoire : sources d'erreurs et corrections possibles, approche expérimentale et modélisation ». Toulouse, ENSAE, 1987. http://www.theses.fr/1987ESAE0014.

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Guingand, Frédéric. « Etude des phénomènes hydro-acoustiques liés au régime pulsatoire du circuit haute pression d'une direction assistée hydraulique ». Lyon, INSA, 2000. http://www.theses.fr/2000ISAL0024.

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L'interaction du débit pulsé généré par la pompe avec le circuit de direction de direction assistée produit des pulsation de pression (bruit hydaulique) qui sont transmises au circuit et aux structures d'accueil (bruit solidien), conduisant à du bruit aérien dans le véhicule. Actuellement, la mise au point de ce type de système, exclusiovement expérimentale et itérative, est coûteuse en moyens et en temps. La démarche mise en place dans le cadre de cette étude permet d'orienter la conception des circuits, de faciliter la mise au point expérimentale et de développer une méthodologie basée sur les outils de simulation numérique qui ouvre la voie à une conception vibro-acoustique prédictive. C'est une approche linéaire couvrant la plage de fréquences allant de 100 à 3000 Hz. Elle repose sur la " méthode des impédances " : chaque composant est représenté par des relations linéaires liants entre elles les transformées de Fourier des variables de pression et de débit des interfaces de connexion. La réponse du système est déterminée par assemblage des caractéristiques des différents constituants. Celles-ci sont obtenues expérimentalement dans un premier temps, ce qui a nécessité le développement d'une technique de caractérisation et de moyens d'essais appropriés. La constitution d'une bibliothèque de composants donne la possibilité de simuler des circuits nouveaux tandis que l'analyse des caractéristiques de différents composants permet de déterminer leurs performances intrinsèques et ainsi d'orienter le choix du concepteur. Dans un second temps des modèles de soutenance sont établis et corrélés avec l'expérimentation. Le paramétrage de ces modèles (par la géométrie) offre alors la possibilité de rechercher une optimisation du circuit selon des critères d'atténuation définis sur des plages de fréquences cibles. La méthodologie a été appliquée à un système réel et les résultats de simulation ont été confrontés avec des mesures in situ
The interaction of the pulsated flow generated by the pump with the power-assisted steering circuit produces pressure ripples (fluid born noise) which are transmitted to the circuit and supporting structures (structure born noise), leading to airborne noise in the passenger car. Currently, the "tuning" of this type of system, exclusively experimental and iterative, is expensive in means and time. The methodology developed in this study makes it possible to direct the design of the circuits, to facilitate the experimental development, to install a process based on numerical simulation which opens the way to predictive vibroacoustic design. It is a linear approach covering the range of frequencies going from 100 to 3000 Hz. It relies on the "impedance method": each component is represented b linear relations between Fourier transform of the pressure and flow variables 011 the connection interfaces. The response of the system is then determined by assembly of the characteristics of the various components. Those are first obtained experimentally; what required the development of a characterization technique and suitable test facilities. The constitution of a library of components allows the simulation of new circuits whereas the analysis of the characteristics of various components makes it possible to determine their intrinsic performances and thus to direct the choice of the designer. In the second time, knowledge models are established and correlated with the experimentation. The parameter setting of these models (by the geometry) gives the opportunity to seek an optimization of the circuit according to attenuation criteria defined on target ranges of frequencies. The methodology was applied to a real system and the simulation results were confronted with in situ measurements

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Ben, Abdessalem Khaled. « Etude de l'écoulement pulsatile d'un fluide visqueux dans un milieu viscoélastique non linéaire et présentant deux sites de réflexion : application à l'écoulement du sang dans les artères ». Paris 7, 2008. http://www.theses.fr/2008PA077212.

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La connaissance des grandeurs hémodynamiques du système cardio-vasculaire en relation avec les donnée pathologiques ou physiologiques, a été le sujet de nombreux travaux de recherches durant les dernières décennies. Le bi de cette thèse de doctorat été de promouvoir les possibilités d'investigation non intrusive du système artériel, lesquelle sont basées sur l'utilisation des techniques vélocimétriques et échographique ultrasonores. Nous avons développ différents méthodes qui permettent une quantification non-invasive des grandeurs hémodynamiques d'intérêt clinique dan un tronc artériel. Nous avons présenté dans un premier temps une méthode de détermination du coefficient de propagatior basée sur la mesure simultanée de la vitesse ou du rayon en trois sections d'un tronc artériel. Dans un deuxième temp* nous avons présenté une nouvelle méthode d'évaluation de cette grandeur, basée sur la mesure non invasive de la vitesse c du rayon seulement en deux sections d'un tube ou d'un arbre artériel. Ainsi définie, ces méthodes ont été validées pa simulation numérique dans des conditions géométriques et physiques variées en présence du bruit. Dans la deuxième parti de ce travail, nous avons développé une méthode qui permet l'évaluation de la vitesse d'onde moyennant la mesure d vitesse et de la section en un seul site. Les résultats des expériences menées sur banc hydrodynamique ont été comparés des modèles classiques de la littérature. Nous avons présenté ensuite deux méthodes en vue de l'évaluation de la distanc du site de réflexion. Ce travail à été achevé par le développement d'un modèle qui tient compte de la présence de deux site de réflexions, le modèle permet de remonter au débit, la pression in-stationnaire et l'impédance d'entrée
The knowledge of hemodynamic quantities of the cardiovascular System in relation to pathological or physiological data h£ been the subject of much research in recent decades. The aim of this thesis was to study the possibility of non-intrusive investigation of the arterial System, which is based on the use of ultrasound measurement. We have developed seven methods for non-invasive quantification of hemodynamic quantities of clinical interest. We presented in a first time a method for determining the propagation coefficient, based on simultaneous measurement of the velocity or radius into three section of an arterial trunk. In a second time, we presented a new method of measuring this quantity, based on non-invasive measurement of the velocity and radius at only two sections of a tube or an arterial tree. These methods have been validate by numerical simulation for various geometrical and physical conditions in the presence of noise. In the second part of the work, we developed a method that allows estimation of wave speed through the measurement of velocity and the section in single site. The results of experiments on hydrodynamics banc were compared with classic models of literature. We the presented two methods for the assessment of the distance from the reflection site. Finally we have developed a model the takes into account the presence of two reflections sites. The model allows Computing the flow, the unsteady pressure and the impedance

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Bokov, Plamen. « Description expérimentale et numérique de l'interaction entre un stent biodégradable et la paroi artérielle ». Paris 7, 2011. http://www.theses.fr/2011PA077109.

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Ce travail porte sur l'étude expérimentale et numérique de l'interaction entre un stent biodégradable et la paroi artérielle. Deux types de stents ont été explorés, un stent en acier inoxydable et un en polymère biodégradable le PLLA-PTT (copolymère de poly-L-acide lactique et de polytrimethylène terephtalate). En utilisant des simulations numériques 3D simplifiées, utilisant la notion de pression équivalente, nous montrons que le stent biodégradable est capable d'assurer une dilatation post-angioplastique de 7% de la lumière vasculaire initiale. Dans une partie expérimentale, nous montrons que les propriétés mécaniques stent biodégradable (en PLLA) à l'ouverture sont comparables à celle du stent en acier. Une des parties les plus conséquentes de ce travail concerne l'incidence hémodynamique de la présence d'un stent et son effet sur la propagation de puises de pression, la présence de l'implant étant modélisée par une rigidification locale de la paroi ou par une protrusion à l'intérieur de la lumière vasculaire. L'incidence sur la distribution spatio-temporelle des contraintes de cisaillement visqueuses au niveau de la paroi y est examinée en détail et il est montré que la présence du stent perturbe de manière significative les contraintes au voisinage de la zone stentée, l'effet s'étendant à quelques centimètres en amont et en aval de cette zone. L'analyse détaillée des perturbations des contraintes visqueuses pariétales, facteur déterminant du phénomène de remodelage tissulaire, s'avère déterminant pour prévoir les risques majeurs de resténose
We have addressed the interaction between a biodegradable coronary stent and the arterial wall using experimental methods and a 3D numerical simplified model based on an equivalent pressure hypothesis. Two types of stents are investigated numerically: a PLLA-PTT stent (poly-L-lactic acid and polytrimethylene terephtalate copolymer) and a stainless steel stent. Three dimensional finite element simulations of the opening mechanics permitted to establish that a post-angioplastic dilatation of 7% is possible by using biodegradable stents. On the other hand, we show experimentally that the radial strength of biodegradable stents in PLLA is comparable to that of stainless steel stents. An important part of this work is devoted to the characterization of hemodynamical incidence of the stent and the pressure pulse reflection when a two dimensional axisymmetric geometrical configuration of the stent-artery System is considered. The stent is either represented as a local hardening of the arterial wall or as a geometrical protrusion in the arterial lumen. The impact on the spatial and temporal distribution of the shear rate at the wall is examined in detail and it is shown that the presence of the stent significantly disturbs the constraints near the site of stenting. This effect is extended a few centimeters upstream and downstream of the stented area. The detailed analysis of perturbations of the parietal viscous stress is a critical factor predicting the major risks of restenosis

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De, Assis Peralta Raphaël. « Caractériser les populations stellaires à l'aide d'indices sismiques ». Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066106/document.

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A l'instar de la sismologie terrestre, l'astérosismologie est l'étude des tremblements d'étoiles. Ces vibrations internes sont observées via les variations de luminosité (ou de vitesse) qui se manifestent à leurs surfaces. A partir de ces séries temporelles, on calcule les spectres de puissance qui contiennent une véritable mine d'informations. En particulier, pour les pulsateurs de types solaires, nous pouvons observer le signal de la granulation ainsi que les modes propres d'oscillations stellaires qui sont tous deux une conséquence directe de la convection dans l'enveloppe de l'étoile. L'astérosismologie permet de sonder l'intérieur des étoiles comme une échographie. Par ailleurs, avec les grands relevés de photométrie spatiale CoRoT et Kepler, un nouveau champ d'application pour la sismologie est apparu. En effet, il est possible de caractériser au premier ordre les spectres d'oscillations des pulsateurs de types solaires à partir de quelques indices que nous appellerons indices sismiques. Ces derniers permettent via des relations simples d'estimer les paramètres fondamentaux de ces étoiles. Cela fait de l'astérosismologie un outil très puissant pour l'étude des populations stellaires.Dans la perspective du développement de la base de données Stellar Seismic Indices (SSI - Ouverture de la base SSI prévue pour l'été 2016. Lien vers la base: http://ssi.lesia.obspm.fr/), l'objet de ma thèse a été de développer une méthode automatique capable d'extraire simultanément les indices sismiques et les paramètres caractérisant la granulation des pulsateurs de types solaires. Cette méthode, appelée MLEUP, a été pour l'instant optimisée pour les géantes rouges car CoRoT et Kepler ont observé plusieurs dizaines de milliers de géantes rouges contre quelques centaines de pulsateurs de type solaire de séquence principale. Le MLEUP présente un avantage majeur par rapport à la plupart des méthodes existantes : il utilise le patron universel d'oscillations (UP) des géantes rouges comme modèle d'ajustement du spectre d'oscillations, ce qui permet d'analyser le spectre non lissé, donc non dégradé, et d'ajuster simultanément la composante de granulation et celle des oscillations par l'estimation du maximum de vraisemblance (MLE). Le MLEUP a dans un premier temps été testé par des simulations Monte Carlo afin de quantifier ses performances. Ces dernières se sont révélées très bonnes, avec de faibles biais et dispersions. Dans un second temps, nous avons appliqué le MLEUP à plus de 36.500 étoiles observées par CoRoT et Kepler, parmi lesquelles nous obtenons les indices sismiques et les paramètres de la granulation pour plus de 13.500 étoiles. Ces résultats ont d'ores et déjà été utilisés dans plusieurs travaux et leur utilisation devrait s'intensifier rapidement
Like terrestrial seismology, asteroseismology is the study of star quakes. These internal vibrations are detected by observing the luminosity (or velocity) variations at the stellar surfaces. From these time series, one computes power spectra which contain a wealth of information. In particular, for solar-like pulsators, we are able to observe the signal of granulation as well as the eigenmodes of stellar oscillations, both of which are a direct consequence of the convection in the star's envelope. Asteroseismology allows us to probe the interior of stars much like an ultrasound. Furthermore, with the large spatial photometric surveys CoRoT and Kepler, a new scope for seismology appeared. Indeed, it is possible to characterise to first order the oscillation spectra of solar-like pulsators with few indices or parameters, called seismic indices. Using simple relations, they allow us to estimate fundamental parameters of these stars. Asteroseismology is by consequence a very powerful tool for the study of stellar populations.In the perspective of the development of the Stellar Seismic Indices (SSI - The opening of the SSI database is planned for the summer of 2016, see http://ssi.lesia.obspm.fr/).) database, the purpose of my thesis was to develop an automatic method able to extract simultaneously the seismic indices and the parameters characterizing the granulation signature of solar-like pulsators. This method, called MLEUP, was optimized for red giants because for the few hundred main-sequence solar-like pulsators observed by CoRoT and Kepler, several tens of thousands of red giants have been observed by these same missions. MLEUP has a major advantage over most existing methods: it relies on the use red-giant stellar oscillation universal pattern (UP) to fit the oscillation spectra. This allows us to analyse the unsmoothed spectrum and fit simultaneously both granulation and oscillations with the maximum likelihood estimate (MLE).As a first step, MLEUP was tested on Monte Carlo simulations in order to quantify its performances. These simulations have revealed that MLEUP achieves very good performances, with low biases and dispersions. As a second step, we applied MLEUP to more than 36,500 stars observed by CoRoT and Kepler, thereby yielding seismic indices and granulation parameters for more than 13,500 stars. Those results have already been used in several works and are expected to be used in many more

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Tardu, Sedat. « Ecoulement turbulent instationnaire près d'une paroi : réponse des structures turbulentes : [thèse en partie soutenue sur un ensemble de travaux] ». Grenoble 1, 1988. http://www.theses.fr/1988GRE10137.

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Livres sur le sujet "Pulsatoria"

Pogorilowski, Andrei. Energii ale timpului muzical : Studii esențiale de funcționalism pulsatoric. Bucharest, Romania : Ararat, 1994.

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1957-, Goupil M. J., Hansen Carl J et United States. National Aeronautics and Space Administration., dir. On the role of resonances in nonradial pulsators. [Washington, DC : National Aeronautics and Space Administration, 1997.

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Varkey, Joseph Valliaara. The Pulsator. Raider Publishing International, 2007.

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Pogorilowski, Andrei. Energies of Musical Time - Essential Studies of Pulsatory Functionalism (English/Romanian). Editura Ararat, 1995.

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Chapitres de livres sur le sujet "Pulsatoria"

Salvi, Paolo. « La pressione pulsatoria ». Dans Onde di polso, 9–16. Milano : Springer Milan, 2012. http://dx.doi.org/10.1007/978-88-470-2424-3_3.

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Rivinius, Th. « Be Stars : Rapidly Rotating Pulsators ». Dans Astrophysics and Space Science Proceedings, 253–59. Berlin, Heidelberg : Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-29630-7_46.

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Goodwin, Richard M. « The Economy as an Evolutionary Pulsator ». Dans The Long-Wave Debate, 27–34. Berlin, Heidelberg : Springer Berlin Heidelberg, 1987. http://dx.doi.org/10.1007/978-3-662-10351-7_4.

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Charpinet, S., G. Fontaine et P. Brassard. « Fundamental Parameters of SDB Pulsators from Asteroseismology ». Dans White Dwarfs, 69–72. Dordrecht : Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-010-0215-8_18.

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O’Brien, M. Sean. « Old Pulsators : White Dwarfs and Their Immediate Precursors ». Dans Asteroseismology Across the HR Diagram, 45–52. Dordrecht : Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-017-0799-2_7.

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Baade, Dietrich, et Werner W. Weiss. « Computed Spectral Line Variations for Oblique Nonradial Pulsators ». Dans Upper Main Sequence Stars with Anomalous Abundances, 234. Dordrecht : Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4714-6_38.

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Kurtz, D. W. « Evidence for, and Development of, the Oblique Pulsator Model ». Dans Variable Stars as Essential Astrophysical Tools, 339–62. Dordrecht : Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-011-4299-1_13.

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Corbet, Robin H. D. « The Three Types of High Mass X-Ray Pulsator ». Dans The Evolution of Galactic X-Ray Binaries, 63–74. Dordrecht : Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4594-4_6.

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Ernst, Floris. « On the Outside : Prediction of Human Respiratory and Pulsatory Motion ». Dans Compensating for Quasi-periodic Motion in Robotic Radiosurgery, 65–130. New York, NY : Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4614-1912-9_4.

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Billères, M., et G. Fontaine. « High Signal-to-Noise Ratio Observations of EC 14026 Pulsators ». Dans White Dwarfs, 65–68. Dordrecht : Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-010-0215-8_17.

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Actes de conférences sur le sujet "Pulsatoria"

Kukhtarev, Nickolai V., Tatiana V. Kukhtareva, Mekonen Bayssie, Tracy D. Hudson, William A. Friday, I. Shkolnikov, Hossin A. Abdeldayem, Benjamin G. Penn et Donald O. Frazier. « Photogalvanic pulsator ». Dans International Symposium on Optical Science and Technology, sous la direction de Francis T. S. Yu et Ruyan Guo. SPIE, 2002. http://dx.doi.org/10.1117/12.452627.

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Majdalani, Joseph, et Hicham Chibli. « Pulsatory Channel Flows with Arbitrary Pressure Gradients ». Dans 3rd Theoretical Fluid Mechanics Meeting. Reston, Virigina : American Institute of Aeronautics and Astronautics, 2002. http://dx.doi.org/10.2514/6.2002-2981.

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Wilson, Matthew, David Lineberry et Marlow Moser. « Experimental Pulsator Characterization for Liquid Injector Research ». Dans 46th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit. Reston, Virigina : American Institute of Aeronautics and Astronautics, 2010. http://dx.doi.org/10.2514/6.2010-7011.

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Bazarov, Vladimir, Erik Lee, David Lineberry, Bryant Swanner et Robert Frederick. « Pulsator Designs for Liquid Rocket Injector Research ». Dans 43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit. Reston, Virigina : American Institute of Aeronautics and Astronautics, 2007. http://dx.doi.org/10.2514/6.2007-5156.

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Wilson, Matthew, David Lineberry et Marlow Moser. « Experimental Pulsator Characterization for Liquid Injector Research ». Dans 45th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit. Reston, Virigina : American Institute of Aeronautics and Astronautics, 2009. http://dx.doi.org/10.2514/6.2009-5491.

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Muntges, Daniel, et Joseph Majdalani. « Pulsatory Channel Flow for an Arbitrary Volumetric Flowrate ». Dans 32nd AIAA Fluid Dynamics Conference and Exhibit. Reston, Virigina : American Institute of Aeronautics and Astronautics, 2002. http://dx.doi.org/10.2514/6.2002-2856.

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Salmon, Sébastien, Josefina Montalbán, Andrea Miglio, Thierry Morel, Marc-Antoine Dupret, Arlette Noels, Joyce Ann Guzik et Paul A. Bradley. « The Enigma of B-type Pulsators in the SMC ». Dans STELLAR PULSATION : CHALLENGES FOR THEORY AND OBSERVATION : Proceedings of the International Conference. AIP, 2009. http://dx.doi.org/10.1063/1.3246521.

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Hayes, Brandon, Austin Hayes, Matthew Rolleston, Alexander Ferreira et James Krisher. « Pulsatory Mixing of Laminar Flow Using Bubble-Driven Micro-Pumps ». Dans ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-86937.

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Y-shaped microfluidic channels have been built with Computer Numerical Control (CNC) and laser cutting manufacturing techniques. Fluid is delivered to each port via external syringe pumps. Each Y-shaped channel contains thermal inkjet (TIJ) resistors built using conventional microfabrication techniques. The resistors vaporize water and generate drive bubbles. This work focuses on utilizing TIJ technology as an active mixing technique in microfluidics. By varying the electrical firing frequency of the resistors, fluid was successfully mixed with an effective mixing length equal to the length of the TIJ resistor. As such, we demonstrate the use of TIJ resistors as a scalable, active mixing approach in microfluidics. A metric to characterize the extent of mixing using TIJ resistors was proposed and utilized. In addition, the fundamental framework of TIJ bubble dynamics with respects to mixing was assessed.

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Richter, Andreas, et Petr A. Nikrityuk. « Heat and fluid flow past spherical particles in pulsatory flows ». Dans THMT-12. Proceedings of the Seventh International Symposium On Turbulence, Heat and Mass Transfer Palermo, Italy, 24-27 September, 2012. Connecticut : Begellhouse, 2012. http://dx.doi.org/10.1615/ichmt.2012.procsevintsympturbheattransfpal.540.

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Despotovic, Svetlana, Zeljko Despotovic et Srdjan Sudarevic. « High performances signal generator implemented on two axes hydraulic pulsator ». Dans IEEE EUROCON 2009 (EUROCON). IEEE, 2009. http://dx.doi.org/10.1109/eurcon.2009.5167834.

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