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Artigos de revistas sobre o assunto "BEMs rapides"
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Zhang, Chenchu, Hanchang Ye, Rui Cao, Shengyun Ji, Heng Zhang, Linhan Zhao, Sizhu Wu e Hua Zhai. "Rapid fabrication of microrings with complex cross section using annular vortex beams". Chinese Optics Letters 20, n.º 2 (2022): 023801. http://dx.doi.org/10.3788/col202220.023801.
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Patterson, Thomas E., Yoshitada Sakai, Mark D. Grabiner, Michael Ibiwoye, Ronald J. Midura, Maciej Zborowski e Alan Wolfman. "Exposure of murine cells to pulsed electromagnetic fields rapidly activates the mTOR signaling pathway". Bioelectromagnetics 27, n.º 7 (2006): 535–44. http://dx.doi.org/10.1002/bem.20244.
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Month, Mel. "Education in a rapidly advancing technology: Accelerators and beams". American Journal of Physics 68, n.º 6 (junho de 2000): 556–70. http://dx.doi.org/10.1119/1.19484.
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Wu, Ke, Bruno D. Welfert e Juan M. Lopez. "Librational forcing of a rapidly rotating fluid-filled cube". Journal of Fluid Mechanics 842 (13 de março de 2018): 469–94. http://dx.doi.org/10.1017/jfm.2018.157.
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The flow response of a rapidly rotating fluid-filled cube to low-amplitude librational forcing is investigated numerically. Librational forcing is the harmonic modulation of the mean rotation rate. The rotating cube supports inertial waves which may be excited by libration frequencies less than twice the rotation frequency. The response is comprised of two main components: resonant excitation of the inviscid inertial eigenmodes of the cube, and internal shear layers whose orientation is governed by the inviscid dispersion relation. The internal shear layers are driven by the fluxes in the forced boundary layers on walls orthogonal to the rotation axis and originate at the edges where these walls meet the walls parallel to the rotation axis, and are hence called edge beams. The relative contributions to the response from these components is obscured if the mean rotation period is not small enough compared to the viscous dissipation time, i.e. if the Ekman number is too large. We conduct simulations of the Navier–Stokes equations with no-slip boundary conditions using parameter values corresponding to a recent set of laboratory experiments, and reproduce the experimental observations and measurements. Then, we reduce the Ekman number by one and a half orders of magnitude, allowing for a better identification and quantification of the contributions to the response from the eigenmodes and the edge beams.
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Riahinezhad, Marzieh, Madeleine Hallman e J.-F. Masson. "Critical Review of Polymeric Building Envelope Materials: Degradation, Durability and Service Life Prediction". Buildings 11, n.º 7 (7 de julho de 2021): 299. http://dx.doi.org/10.3390/buildings11070299.
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This paper provides a critical review of the degradation, durability and service life prediction (SLP) of polymeric building envelope materials (BEMs), namely, claddings, air/vapour barriers, insulations, sealants, gaskets and fenestration. The rate of material deterioration and properties determine the usefulness of a product; therefore, knowledge of the significant degradation mechanisms in play for BEMs is key to the design of proper SLP methods. SLP seeks to estimate the life expectancy of a material/component exposed to in-service conditions. This topic is especially important with respect to the potential impacts of climate change. The surrounding environment of a building dictates the degradation mechanisms in play, and as climate change progresses, material aging conditions become more unpredictable. This can result in unexpected changes and/or damages to BEMs, and shorter than expected SL. The development of more comprehensive SLP methods is economically and environmentally sound, and it will provide more confidence, comfort and safety to all building users. The goal of this paper is to review the existing literature in order to identify the knowledge gaps and provide suggestions to address these gaps in light of the rapidly evolving climate.
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Huang, Xin Zhang, Xiu Li Zhang, Jun Rui Shi, Zhi Jia Xue, You Ning Xu e Shu Qun Wang. "Experimental Study on CH4 / Air Diffusion Combustion on the Upper Surface of Porous Media Packed Beds". Advanced Materials Research 516-517 (maio de 2012): 62–65. http://dx.doi.org/10.4028/www.scientific.net/amr.516-517.62.
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This paper experimentally study on CH4/ air co-flow diffusion combustion on the upper surface of porous media packed beds. The flame height and flame shape were reconstructed from the upper and the side of the combustor. The influence of the height of the packed bed on the flame height and flame shape is reported. It is shown that the flame height decreases rapidly and the circular diameter increases rapidly with increase the height of the packed beds.
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Rivers, James W., e Matthew G. Betts. "Postharvest Bee Diversity is High but Declines Rapidly with Stand Age in Regenerating Douglas-Fir Forest". Forest Science 67, n.º 3 (25 de março de 2021): 275–85. http://dx.doi.org/10.1093/forsci/fxab002.
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Abstract Concerns about long-term pollinator declines have made assessing bee communities a priority in nonagricultural ecosystems, including managed forests. We assessed wild bee communities in Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) stands one to 15 years after clearcut harvest in western Oregon, USA, testing the hypothesis that bee diversity would be high initially and then decline with time-dependent reductions in floral resources. We captured 2,009 individual bees that represented 67 distinct species/morphospecies in 20 genera and five families. Asymptotic estimators of bee diversity representing Shannon and Simpson diversity were greater in communities during the second half of the early seral period, indicating older early seral stands were less diverse and contained more common and dominant bee species. In addition, observed species richness and bee abundance peaked at approximately three years postharvest and declined thereafter by 20% and 30% per year, respectively. Because floral resources declined in concert with reductions in bee diversity as stands aged, food appears to be a key driver of forest bee communities. Our results indicate that postharvest Douglas-fir stands supported a diversity of bees, including important crop pollinators, but their value to bees was restricted to a relatively short window at the beginning of the early seral period.
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Zhang, Kuang, Yuxiang Wang, Yueyi Yuan e Shah Nawaz Burokur. "A Review of Orbital Angular Momentum Vortex Beams Generation: From Traditional Methods to Metasurfaces". Applied Sciences 10, n.º 3 (4 de fevereiro de 2020): 1015. http://dx.doi.org/10.3390/app10031015.
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In this paper, we review the generation of vortex beams carrying orbital angular momentum in the microwave domain. We firstly present the theory of Laguerre–Gaussian beams where it is demonstrated that they carry such type of momentum. We further provide an overview of the classical methods used to generate orbital angular momentum vortex beams, which rely on two main methods; plane wave to vortex wave conversion and direct generation using radiating antennas. Then, we present recent progress in the physics of metasurfaces devoted to the generation of vortex beams with a discussion about reflective and transmissive metasurfaces for plane wave to vortex wave conversion as well as methods to reduce the intrinsic divergence characteristics of vortex beams. Finally, we conclude on this rapidly developing research field.
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Liu, Can. "Shear Capacity Research on Transversely Reinforced Concrete Beams". Applied Mechanics and Materials 744-746 (março de 2015): 283–87. http://dx.doi.org/10.4028/www.scientific.net/amm.744-746.283.
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Inner transverse prestressed bars were used to enhance the shear capacity of concrete beams in this paper, which can be used in transformer beams to reduce the sectional size. Two transversely prestressed one ordinary concrete beams were tested and calculated by finite element method, and the following conclusions can be drawn: (a)The shear capacity of transversely prestressed concrete beam increase rapidly with the increase of the prestressing force level, which means that prestressing force level has a great influence on the shear capacity of transversely prestressed concrete beam. (b) The transverse prestressing bars can efficiently enhance the anti-crack performance of the reinforced concrete beams.
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Blanchet, Jose H., e Carlos G. Pacheco-González. "UNIFORM CONVERGENCE TO A LAW CONTAINING GAUSSIAN AND CAUCHY DISTRIBUTIONS". Probability in the Engineering and Informational Sciences 26, n.º 3 (8 de junho de 2012): 437–48. http://dx.doi.org/10.1017/s0269964812000101.
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A source of light is placeddinches apart from the center of a detection bar of lengthL≥d. The source spins very rapidly, while shooting beams of light according to, say, a Poisson process with rate λ. The positions of the beams, relative to the center of the bar, are recorded for those beams that actually hit the bar. Which law best describes the time-average position of the beams that hit the bar given a fixed but long time horizont? The answer is given in this paper by means of a uniform weak convergence result inL, dast→ ∞. Our approximating law includes as particular cases the Cauchy and Gaussian distributions.
Teses / dissertações sobre o assunto "BEMs rapides"
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Bagur, Laura. "Modeling fluid injection effects in dynamic fault rupture using Fast Boundary Element Methods". Electronic Thesis or Diss., Institut polytechnique de Paris, 2024. http://www.theses.fr/2024IPPAE010.
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Les tremblements de terre d'origine naturelle ou anthropique provoquent d'importants dégâts humains et matériels. Dans les deux cas, la présence de fluides interstitiels influe sur le déclenchement des instabilités sismiques. Une nouvelle question d'actualité dans la communauté est de montrer que l'instabilité sismique peut être atténuée par un contrôle actif de la pression des fluides. Dans ce travail, nous étudions la capacité des méthodes d'éléments de frontière rapides (Fast BEMs) à fournir un solveur robuste multi-physique à grande échelle nécessaire à la modélisation des processus sismiques, de la sismicité induite et de leur atténuation.Dans une première partie, un solveur BEM rapide avec différents algorithmes d'intégration temporelle est utilisé. Nous évaluons les performances de diverses méthodes à pas de temps adaptatif sur la base de problèmes de cycles sismiques 2D usuels pour les failles planes.Nous proposons une solution asismique analytique pour effectuer des études de convergence et fournir une comparaison rigoureuse des capacités des différentes méthodes en plus des problèmes de cycles sismiques de référence testés.Nous montrons qu'une méthode hybride prédiction-correction / Runge-Kutta à pas de temps adaptatif permet non seulement une résolution précise mais aussi d'incorporer à la fois les effets inertiels et les couplages hydro-mécaniques dans les simulations de rupture dynamique de faille.Dans une deuxième partie, une fois les outils numériques développés pour des configurations standards, notre objectif est de prendre en compte les effets de l'injection de fluide sur le glissement sismique. Nous choisissons le cadre poroélastodynamique pour incorporer les effets de l'injection sur l'instabilité sismique. Un modèle poroélastodynamique complet nécessiterait des coûts de calcul ou des approximations non négligeables. Nous justifions rigoureusement quels effets fluides prédominants sont en jeu lors d'un tremblement de Terre ou d'un cycle sismique. Pour cela, nous effectuons une analyse dimensionnelle des équations, et illustrons les résultats en utilisant un problème de poroelastodynamique 1D simplifié. Plus précisément, nous montrons qu'à l'échelle de temps de l'instabilité sismique, les effets inertiels sont prédominants alors qu'une combinaison de la diffusion du fluide et de la déformation élastique de la matrice solide due à la variation de la pression interstitielle devrait être privilégiée à l'échelle de temps du cycle sismique, au lieu du modèle de diffusion principalement utilisé dans la littératureEarthquakes due to either natural or anthropogenic sources cause important human and material damage. In both cases, the presence of pore fluids influences the triggering of seismic instabilities.A new and timely question in the community is to show that the earthquake instability could be mitigated by active control of the fluid pressure. In this work, we study the ability of Fast Boundary Element Methods (Fast BEMs) to provide a multi-physic large-scale robust solver required for modeling earthquake processes, human induced seismicity and their mitigation.In a first part, a Fast BEM solver with different temporal integration algorithms is used. We assess the performances of various possible adaptive time-step methods on the basis of 2D seismic cycle benchmarks available for planar faults. We design an analytical aseismic solution to perform convergence studies and provide a rigorous comparison of the capacities of the different solving methods in addition to the seismic cycles benchmarks tested. We show that a hybrid prediction-correction / adaptive time-step Runge-Kutta method allows not only for an accurate solving but also to incorporate both inertial effects and hydro-mechanical couplings in dynamic fault rupture simulations.In a second part, once the numerical tools are developed for standard fault configurations, our objective is to take into account fluid injection effects on the seismic slip. We choose the poroelastodynamic framework to incorporate injection effects on the earthquake instability. A complete poroelastodynamic model would require non-negligible computational costs or approximations. We justify rigorously which predominant fluid effects are at stake during an earthquake or a seismic cycle. To this aim, we perform a dimensional analysis of the equations, and illustrate the results using a simplified 1D poroelastodynamic problem. We formally show that at the timescale of the earthquake instability, inertial effects are predominant whereas a combination of diffusion and elastic deformation due to pore pressure change should be privileged at the timescale of the seismic cycle, instead of the diffusion model mainly used in the literature
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Kralj, Jasna. "Selection of honey bees with rapid development as a component of Varroa mite resistance". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ33242.pdf.
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Delaney, James Carroll. "Suppression of vapor explosions during rapid quenching of char beds in chemical recovery boilers". Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/17780.
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Galvin, Janine E. "On the hydrodynamic description of binary mixtures of rapid granular flows and gas-fluidized beds". Connect to online resource, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3284494.
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Zara, Henri. "Système d'acquisition vidéo rapide : application à la mécanique des fluides". Saint-Etienne, 1997. http://www.theses.fr/1997STET4012.
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Les systèmes de vision sont aujourd'hui largement employés pour les études expérimentales en mécanique des fluides. Les techniques d'acquisition d'images se heurtent cependant à une limitation technologique concernant la cadence et la résolution des images. De nouveaux capteurs d'images électroniques rapides, mais également certaines méthodes d'exposition permettent d'apporter des solutions à ce problème. Nous présentons dans ce mémoire un système d'acquisition vidéo rapide élaboré autour d'une plate-forme expérimentale de mécanique des fluides. Ce système est constitué en particulier : d'une camera CCD numérique (8bits) de résolution 512x512 pixels avec une cadence de 100 i/s ; d'un système de synchronisation qui assure les différents modes d'exposition des images ainsi que la synchronisation des éléments de la plate-forme. L'ensemble est commandé par un ordinateur PC, pour la configuration des paramètres ainsi que pour le stockage des images. La technique d'éclairage mise en oeuvre est la tomographie laser. Un choix technologique original nous a conduit au couplage de la camera à un intensificateur de lumière. Ce choix permet l'utilisation de sources laser continues de faible puissance. Il offre également de larges possibilités d'exposition des images par la commande de la porte optique de l'intensificateur. Dans une première partie nous présentons une étude détaillée des capteurs d'images à semi-conducteur, ainsi que des intensificateurs d'images. Les descriptions techniques concernant la réalisation de la caméra et du système de synchronisation sont ensuite exposées. L'ensemble d'acquisition vidéo final met en oeuvre deux cameras synchronisées permettant l'enregistrement d'une séquence de paires d'images d'occurrence très proche (50 ns). Quelques exemples expérimentaux permettent de confirmer les possibilités de notre système
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Nemitz, N. "Méthode multipôle rapide et sensibilité topologique pour l'identification approchée de défauts à partir de données de type acoustique". Phd thesis, Ecole Polytechnique X, 2006. http://tel.archives-ouvertes.fr/tel-00120202.
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Contexte.Le but de ce travail est de proposer une contribution au traitement numérique de la detection d'obstacles rigides dans des domaines acoustiques tridimensionnels bornés dont la taille est grande relativement à la longueur d'onde. Ce contexte peut être considéré comme un problème modèle, représentatif de situations physiquement plus complexes associées au contrôle non destructif, et relevant pour ses aspects théoriques de la diffraction inverse. Le contexte de la diffraction inverse présente de nombreuses difficultés sur le plan des méthodes numériques, et une grande partie des références traitant de ce type d'inversion se placent dans l'hypothèse d'un milieu infini. Celle-ci est plus pertinente pour des applications en électromagnétisme, telles que la furtivité radar, que pour l'identification de défauts dans des structures.
Nous nous plaçons donc dans le cadre classique de l'acoustique linéaire avec un domaine éclairé par des sources monochromatiques. Par ailleurs, on part du principe, également classique, de poser le problème d'inversion (identification de la position et la taille des obstacles) en termes de l'optimisation d'une fonction coût. La procédure alors employée est itérative, elle consiste à résoudre le problème direct pour des obstacles hypothétiques d'essais. Vu le coût de résolution d'un problème direct, cette approche préfère en général les algorithmes utilisant le gradient que les approches type évolutionnaire.
1 -- Résolution du problème acoustique direct par la méthode multipôle rapide. Le premier aspect sur lequel ce travail s'est penché porte sur l'accélération du problème direct (calcul du champ acoustique pour une configuration donnée d'obstacle), indispensable pour évaluer la fonction-coût du problème inverse. Plusieurs méthodes numériques existent pour cela, chacune ayant des avantages et des inconvénients ; on citera les éléments finis, les différences finies et les éléments de frontière. La méthode des éléments de frontière, qui nécessite uniquement le maillage de la frontière du domaine, est bien adaptée à la résoution du problème inverse, le remaillage nécessité par un changement de configuration d'obstacle étant très simple. L'équation intégrale conduit à un système linéaire dont la matrice est pleine et complexe, ce qui limite sévèrement (besoin mémoire O(N2) et temps de calcul O(N3)) la taille numérique (nombre N d'inconnues nodales sur les éléments de frontière) des problèmes si un solveur direct est employé. Pour traiter les calculs de grande taille occasionnés par le contexte 3D, on est ainsi amené à faire appel à un solveur itératif, qui ne demande pas le stockage de la matrice. La rapidité de résolution dépend alors essentiellement de celle du calcul d'un produit matrice-vecteur. Cette opération est a priori de complexité O(N2), rédhibitoire pour les cas de grande taille (domaine grand devant la longueur d'onde). La Fast Multipole Method (FMM), initialement proposée par Greengard et Rohklin vers 1985 et depuis étendue aux formulations intégrales de nombreux problèmes de la physique, permet d'accélérer cette phase cruciale du calcul et réduire la complexité d'un produit matrice-vecteur à O(NlogN) en dynamique.
La mise en oeuvre de la FMM pour l'acoustique linéaire en 3D est ainsi l'une des composantes importantes de ce travail. Elle s'appuie sur des études récentes (en particulier thèse Sylvand, ENPC, 2002; articles E. Darve, 2000s) effectuées dans le cadre de la résolution numérique des équations de Maxwell. Le code issu de ce travail de thèse vérifie en particulier la complexité O(NlogN) théorique, et a été validé sur des solutions exactes de l'acoustique 3D.
2 -- Méthode d'identification approchée d'obstacles par sensibilité topologique. Le second point étudié porte sur l'initialisation des algorithmes d'inversion utilisant la minimisation de la fonction coût. Les algorithmes globaux (par exemple de type évolutionnaire) ne sont pas réalistes en raison du très grand nombre de simulations directes nécessaires. Les algorithmes plus classiques utilisant le gradient dépendent des choix initiaux (position, taille, forme, nombre) sur les obstacles à identifier et peuvent ne pas converger pour des choix inadéquats. Des travaux récents (Bonnet et Guzina, 2005, entre autres) ont montré que le calcul du champ de sensibilité topologique associé à la fonction coût du problème inverse (une notion initialement proposée vers 1995 pour l'optimisation topologique des structures) permet d'obtenir de bonnes informations qualitatives sur la localisation d'obstacles à identifier. Le champ de sensibilité topologique, donnant le comportement asymptotique de la fonction-coût sous l'effet de l'apparition d'un obstacle de taille infinitésimale en un point spécifié du milieu, s'exprime comme une combinaison du champ direct et du champ adjoint associé à la fonction-coût, tous deux définis en l'absence d'obstacle. Le calcul de ce champ de sensibilité repose ainsi sur l'évaluation des formules de représentation intégrale donnant les champs direct et adjoint aux points d'une grille d'échantillonnage de la région 3D dans laquelle on cherche à identifier un défaut. Ce calcul, également coûteux a priori (O(NM) pour O(N) DDLs sur la frontière et
O(M) points d'échantillonnage), est lui aussi considérablement accéléré par l'emploi de la FMM. La FMM constitue donc au total une approche numérique bien adaptée à cette méthode d'exploration globale approchée reposant sur la sensibilité topologique. Le calcul FMM du champ de sensibilité topologique a été mis en oeuvre, et son intérêt testé sur des exemples synthétiques d'inversion. En particulier, pour une fonction-coût de type moindres carrés, la sensibilité topologique dépend linéairement des erreurs de mesure, et son calcul est donc moins sensible à ces erreurs que d'autres méthodes d'inversion.
Ce travail débouche donc sur une méthode approchée et rapide, utilisant les deux aspects présentés, qui donne des indications sur le nombre d'obstacles et leurs positions dans le domaine.
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Velpula, Praveen Kumar. "High aspect ratio sub-micron structuring of transparent materials using non-diffractive ultrafast laser beams : dynamics and interaction regimes". Thesis, Saint-Etienne, 2015. http://www.theses.fr/2015STET4005/document.
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Cette thèse se concentre sur la contrôlabilité de l'indice de réfraction au niveau sub-micronique par changements d'indice induits par laser sur de longues dimensions i.e., avec des hauts rapports d'aspect élevés et des sections à l'échelle nanométrique. À cette fin, nous explorons les faisceaux ultracourts de Bessel non-diffractifs d'ordre zéro et les facteurs qui contribuent au confinement de l'énergie au-delà de la limite de diffraction. Le traitement par laser de matériaux transparents à l'aide de faisceaux non diffractifs offre un avantage important pour les structures sub-microniques en volume de haut rapport d'aspect à des fins applicatives en nanophotonique et en nanofluidique. Nous présentons l'effet de différentes conditions de focalisation et de paramètres laser sur la modification de la silice fondue, explorant ainsi les différents régimes d'interaction. Cette thèse aborde essentiellement des conditions modérées de focalisation car elles offrent un régime d'interaction stable sur une large gamme de paramètres laser, permettant l'ingénierie de la dispersion. La durée de l'impulsion laser s'est révélée être essentielle dans la définition du type de modification de l'indice de réfraction ou de modification structurale. Par exemple, l'usinage utilisant des impulsions laser femtosecondes entraîne une augmentation des structures d'indice de réfraction alors que les impulsions laser picosecondes engendrent une cavité uniforme i.e., des structures de faible indice. Pour acquérir un meilleur contrôle et une meilleure précision du dépôt d'énergie laser, un ensemble de mécanismes physiques responsables des dommages induits par laser dans des conditions d'excitation non-diffractives a été observé expérimentalement et examiné par des simulations indiquant le rôle essentiel de la diffusion de la lumière sur les électrons. Des mesures de microscopie pompe-sonde résolues en temps avec une résolution temporelle sub-picoseconde et spatiale sub-micronique donnent accès à l'excitation et à la relaxation dynamique instantanées. La transmission optique dynamique et le contraste de phase offrent des informations complémentaires sur la réponse électronique ou sur celle de la matrice vitreuse. La dynamique ultrarapide des porteurs libres a été particulièrement étudiée puisque le transfert d'énergie des électrons vers le réseau est la clé de transformation ultérieure du matériau. Le rôle de l'excitation instantanée pour différentes durées et énergie d'impulsion laser est exposé. Ainsi, la dynamique complète des porteurs de charge est présentée pour différents paramètres du laser. En particulier, la dynamique d'obtention de structures d'indice de réfraction positif et des cavités uniformes indique deux chemins différents de relaxation électronique et de dépôt de l'énergie: une relaxation rapide par l'intermédiaire de défauts pour les structures d'indice positif et une relaxation thermomécanique lente pour les cavités nanométriques. Enfin, en corrélant les résultats des études résolues en temps, les simulations et les résultats de photoluminescence après irradiation, nous formulons des scénarios potentiels de formation de l'indice de réfraction positif ainsi que des structures d'indice faible ou de vides uniformesThis thesis is focused on the controllability of laser-induced refractive index changes at sub-micron level over long dimensions i.e., with high aspect ratios and sections on the nanoscale. To this end, we explore non-diffractive zerothorder ultrafast Bessel beams and factors contributing to energy confinement beyond the diffraction limit. Laser processing of transparent materials using non-diffracting beams offers a strong advantage for high aspect ratio submicron structures inside the bulk in view of nanophotonics and nanouidics applications. We present the role of various focusing conditions and laser parameters on material modification in bulk fused silica and explore the different interaction regimes. This thesis tackles mostly the moderate focusing conditions as they offer a stable interaction regime backed up dispersion engineering over a large range of laser parameters. The laser pulse duration was found to be key in defining the type of laser induced refractive index or structural modification. For instance, machining using femtosecond laser pulses results in increased refractive index structures whereas picosecond laser pulses result in uniform void i.e., low index structures. To acquire better control over the laser energy deposition and precision, a range of physical mechanisms responsible for the laser induced damage in non-diffractive excitation conditions have been observed experimentally and further interrogated by simulations indicating a critical role of light scattering on carriers. Time-resolved pump-probe microscopy measurements with a sub-picosecond temporal and sub-micron spatial resolution allow access to the instantaneous excitation and relaxation dynamics. Dynamic optical transmission and phase contrast o_er complementary information of either electronic and glass matrix response. Primarily, ultrafast dynamics of free carriers was studied as the electron mediated energy transfer to the lattice is key to the subsequent material transformation. Role of instantaneous excitation at different laser pulse durations and energies is outlined. Then complete carrier dynamics is presented at different laser parameters. Particularly dynamics in conditions of positive refractive index structures and uniform voids is indicating two different paths of electronic relaxation and energy deposition: a fast defect mediated relaxation for positive index structures and slow thermomechanical relaxation for nanosize void structures. Finally, by correlating the results of time resolved studies, simulations and post-irradiated photoluminescence results, we formulate potential formation scenarios for the positive refractive index and low index or uniform void structures
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Alarcón, Díez Víctor. "Development of charged particle detection systems for materials analysis with rapid ion beams : large solid angle detectors and numerical nuclear pulse processing". Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066489/document.
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Cette thèse présente de nouveaux développements en détection de particules chargées et traitement tout-numérique d'impulsions pour application à l'analyse avec des faisceaux d'ions rapides (IBA). Un ensemble de 16 détecteurs gravés sur une puce de Si est mis en œuvre, ce qui fournit un angle solide de détection environ 100 fois plus grande que celle des détecteurs utilisés auparavant pour l'IBA. Seize chaines d'acquisition sont également mises en œuvre avec une approche 'tout-numérique' pour le traitement des signaux issus des détecteurs. Dans son ensemble, le système ainsi développé a une résolution en énergie équivalent à celle des détecteurs standards. La considérable quantité d'information ainsi générée est traitée de manière cohérente en ajustant des spectres en énergie simulé aux spectres mesurés grâce à un algorithme de recuit simulé, avec le NDF DataFurnace. Les grandes angles solides disponibles sont exploitées pour des études par rétrodiffusion de Rutherford (RBS) et canalisation d'ions de l'isolant topologique Bi2Se3 enrichi en fer en vue d'études de l'effet thermoélectrique, de spintronique ou encore la computation quantique, ainsi que pour des études par RBS et analyse par réactions nucléaires (NRA) de matériaux pour la photovoltaïque organique, basés sur tetraphenyldibenzoperiflanthene (DBP) comme photo-absorbant avec oxydes de métaux de transition pour injection de chargeThis thesis presents new developments in charged particle detection and digital pulse processing for application in analysis with fast ion beams - Ion Beam Analysis (IBA). In particular a charged particle detector array, consisting of 16 independent charged particle detectors on a single silicon chip is implemented giving an overall solid angle of detection around two orders of magnitude greater than the standard charged particle detectors used in IBA. Sixteen parallel data acquisition channels are implemented using a fully digital approach for nuclear pulse processing. The overall system has an energy resolution equivalent to that of standard detectors. The large amount of data generated is handled in a self-consistent way by spectrum fitting with a simulated annealing algorithm via the NDF DataFurnace. The large solid angles thus achieved are exploited in Rutherford Backscattering Spectrometry (RBS) and ion channelling studies of the topological insulator Bi2Se3 enriched in Fe, in view of studies of the thermo-electric effect, spintronics and quantum computing, and in RBS and Nuclear Reaction Analysis (NRA) studies of organic photovoltaic materials based on tetraphenyldibenzoperiflanthene (DBP) as the photo-absorber and transition metal oxide charge injectors
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Alarcón, Díez Víctor. "Development of charged particle detection systems for materials analysis with rapid ion beams : large solid angle detectors and numerical nuclear pulse processing". Electronic Thesis or Diss., Paris 6, 2016. http://www.theses.fr/2016PA066489.
Texto completo da fonteResumo:
Cette thèse présente de nouveaux développements en détection de particules chargées et traitement tout-numérique d'impulsions pour application à l'analyse avec des faisceaux d'ions rapides (IBA). Un ensemble de 16 détecteurs gravés sur une puce de Si est mis en œuvre, ce qui fournit un angle solide de détection environ 100 fois plus grande que celle des détecteurs utilisés auparavant pour l'IBA. Seize chaines d'acquisition sont également mises en œuvre avec une approche 'tout-numérique' pour le traitement des signaux issus des détecteurs. Dans son ensemble, le système ainsi développé a une résolution en énergie équivalent à celle des détecteurs standards. La considérable quantité d'information ainsi générée est traitée de manière cohérente en ajustant des spectres en énergie simulé aux spectres mesurés grâce à un algorithme de recuit simulé, avec le NDF DataFurnace. Les grandes angles solides disponibles sont exploitées pour des études par rétrodiffusion de Rutherford (RBS) et canalisation d'ions de l'isolant topologique Bi2Se3 enrichi en fer en vue d'études de l'effet thermoélectrique, de spintronique ou encore la computation quantique, ainsi que pour des études par RBS et analyse par réactions nucléaires (NRA) de matériaux pour la photovoltaïque organique, basés sur tetraphenyldibenzoperiflanthene (DBP) comme photo-absorbant avec oxydes de métaux de transition pour injection de chargeThis thesis presents new developments in charged particle detection and digital pulse processing for application in analysis with fast ion beams - Ion Beam Analysis (IBA). In particular a charged particle detector array, consisting of 16 independent charged particle detectors on a single silicon chip is implemented giving an overall solid angle of detection around two orders of magnitude greater than the standard charged particle detectors used in IBA. Sixteen parallel data acquisition channels are implemented using a fully digital approach for nuclear pulse processing. The overall system has an energy resolution equivalent to that of standard detectors. The large amount of data generated is handled in a self-consistent way by spectrum fitting with a simulated annealing algorithm via the NDF DataFurnace. The large solid angles thus achieved are exploited in Rutherford Backscattering Spectrometry (RBS) and ion channelling studies of the topological insulator Bi2Se3 enriched in Fe, in view of studies of the thermo-electric effect, spintronics and quantum computing, and in RBS and Nuclear Reaction Analysis (NRA) studies of organic photovoltaic materials based on tetraphenyldibenzoperiflanthene (DBP) as the photo-absorber and transition metal oxide charge injectors
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Hernández, Cubero Óscar Rubén. "Méthodes optiques innovantes pour le contrôle rapide et tridimensionnel de l’activité neuronale". Thesis, Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCB005.
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La révolution en cours des outils optogénétiques - des protéines photosensibles génétiquement induites qui peuvent activer, inhiber et enregistrer l'activité neuronale - a permis d'ouvrir une nouvelle voie pour relier l'activité neuronale et la cognition. Néanmoins, pour profiter au mieux de ces outils nous avons besoin de méthodes optiques qui peuvent projeter des schémas d'illumination complexes dans le cerveau. Pendant mon doctorat, j'ai travaillé sur deux nouveaux systèmes complémentaires pour la stimulation de l'activité neuronale. Le premier système combine des déflecteurs acousto-optiques et une illumination Gaussienne à faible ouverture numérique pour produire une photo activation rapide des outils optogénétiques. La capacité d'accès aléatoire du système permet de délivrer des séquences d'illumination spatialement et temporellement complexes qui simulent avec succès les schémas physiologiques de l'activité des fibres moussues dans des tranches de cerveaux. Ces résultats démontrent que les schémas de stimulation optogénétique peuvent être utilisés pour recréer l'activité en cours et étudier les microcircuits du cerveau dans un environnement physiologique. Alternativement, l'holographie générée par ordinateur (HGO) permet d'améliorer grandement les stimulations optogénétiques en répartissant efficacement la lumière sur plusieurs cibles cellulaires simultanément. Néanmoins, le confinement axial se dégrade pour des schémas d'illuminations larges. Afin de d'améliorer ce point, l’HGO peut être combinée avec une technique de focalisation temporelle qui confine axialement la fluorescence sans dépendre de l'allongement latéral. Les précédentes configurations maintiennent l'excitation non linéaire à un unique plan focal spatiotemporel. Dans cette thèse, je décris deux méthodes différentes qui permettent de dépasser ces limitations et de permettre la génération de schémas focalisés tridimensionnellement, à la fois spatialement et temporellementThe ongoing revolution of optogenetic tools – genetically encoded light-sensitive proteins that can activate, silence and monitor neural activity – has opened a new pathway to bridge the gap between neuronal activity and cognition. However, to take full advantage of these tools we need optical methods that can deliver complex light patterns in the brain. During my doctorate, I worked on two novel and complementary optical systems for complex spatiotemporally neural activity stimulation. The first system combined acousto-optic deflectors and low numerical aperture Gaussian beam illumination for fast photoactivation of optogenetic tools. The random-access capabilities of the system allowed to deliver complex spatiotemporal illumination sequences that successfully emulated physiological patterns of cerebellar mossy fiber activity in acute slices. These results demonstrate that patterned optogenetic stimulation can be used to recreate ongoing activity and study brain microcircuits in a physiological activity context. Alternatively, Computer Generated Holography (CGH) can powerfully enhance optogenetic stimulation by efficiently shaping light onto multiple cellular targets simultaneously. Nonetheless, the axial confinement degrades for laterally extended illumination patterns. To address this issue, CGH can be combined with temporal focusing that axially confines fluorescence regardless of lateral extent. However, previous configurations restricted nonlinear excitation to a single spatiotemporal focal plane. In this thesis, I describe two alternative methods to overcome this limitation and enable three-dimensional spatiotemporal focused pattern generation
Livros sobre o assunto "BEMs rapides"
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Sexton, Cornelius L. Rapid alloy scanning by laser cladding. Aachen: Shaker, 1995.
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G, Hieber David, Washington (State). Dept. of Transportation., United States. Federal Highway Administration., United States. National Technical Information Service., Washington State Transportation Center e Washington State Transportation Commission, eds. State-of-the-art report on precast concrete systems for rapid construction of bridges. [Olympia, Wash.]: Washington State Dept. of Transportation, 2005.
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G, Hieber David, Washington (State). Dept. of Transportation., Washington State Transportation Center e Washington State Transportation Commission, eds. State-of-the-art report on precast concrete systems for rapid construction of bridges. [Olympia, Wash.]: Washington State Dept. of Transportation, 2005.
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The effects of rapid heating of soot: Implications when using laser-induced incandescence for soot diagnostics. [Washington, D.C: National Aeronautics and Space Administration, 1995.
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The effects of rapid heating of soot: Implications when using laser-induced incandescence for soot diagnostics. [Washington, D.C: National Aeronautics and Space Administration, 1995.
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McPhee, Daryl. Environmental History and Ecology of Moreton Bay. CSIRO Publishing, 2017. http://dx.doi.org/10.1071/9781486307227.
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The south-east Queensland region is currently experiencing the most rapid urbanisation in Australia. This growth in human population, industry and infrastructure puts pressure on the unique and diverse natural environment of Moreton Bay. Much loved by locals and holiday-goers, Moreton Bay is also an important biogeographic region because its coral reefs, seagrass beds, mangroves and saltmarshes provide a suitable environment for both tropical and temperate species. The bay supports a large number of species of global conservation significance, including marine turtles, dugongs, dolphins, whales and migratory shorebirds, which use the area for feeding or breeding.
Environmental History and Ecology of Moreton Bay provides an interdisciplinary examination of Moreton Bay, increasing understanding of existing and emerging pressures on the region and how these may be mitigated and managed. With chapters on the bay's human uses by Aboriginal peoples and later European settlers, its geology, water quality, marine habitats and animal communities, and commercial and recreational fisheries, this book will be of value to students in the marine sciences, environmental consultants, policy-makers and recreational fishers.
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Lardas, Mark. US Navy Pacific Fleet 1941. Bloomsbury Publishing Plc, 2024. http://dx.doi.org/10.5040/9781472859495.
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The first book to examine the battleship-led 1941 Pacific Fleet as it was intended to fight. Packed with illustrations, this study explains how the US Navy saw the approaching war unfolding. When the Japanese attacked Pearl Harbor, the Pacific Fleet was the most powerful in the US Navy. It was still dominated by battleships, but since the late 1930s had been developing naval aviation and integrating them with its battleship-led doctrine. This book is the first to examine the Pacific Fleet as it was intended to fight, and how it had been training and preparing in the months leading up to December 7, 1941. Naval historian Mark Lardas explains how, contrary to modern assumptions, it was not wedded to the battleship, but was hedging its bets, building up both its carrier and battleship strength. Most crucially, it had also been building and honing a massive fleet train, enabling the Pacific Fleet to operate easily thousands of miles from home. It was this foundation that enabled the Pacific Fleet to adapt so rapidly to the new world of carrier-led naval warfare, and first check and then defeat the IJN. With artwork, photos and diagrams, this is a portrait of 1941 in the Pacific Fleet, the last time and place when battleship doctrine held sway. Pearl Harbor would shatter this, and herald the start of the carrier era. The blow fell heavily on the US Pacific Fleet, but it and its successors would emerge more powerful than ever.
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Golper, Thomas A., Andrew A. Udy e Jeffrey Lipman. Drug dosing in acute kidney injury. Editado por William G. Bennett. Oxford University Press, 2015. http://dx.doi.org/10.1093/med/9780199592548.003.0364.
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Drug dosing in acute kidney injury (AKI) is one of the broadest topics in human medicine. It requires an understanding of markedly altered and constantly changing physiology under many disease situations, the use of the drugs to treat those variety of diseases, and the concept of drug removal during blood cleansing therapies. Early in AKI kidney function may be supraphysiologic, while later in the course there may be no kidney function. As function deteriorates other metabolic pathways are altered in unpredictable ways. Furthermore, the underlying disorders that lead to AKI alter metabolic pathways. Heart failure is accompanied by vasoconstriction in the muscle, skin and splanchnic beds, while brain and cardiac blood flow proportionally increase. Third spacing occurs and lungs can become congested. As either kidney or liver function deteriorates, there may be increased or decreased drug sensitivity at the receptor level. Acidosis accompanies several failing organs. Protein synthesis is qualitatively and quantitatively altered. Sepsis affects tissue permeability. All these abnormalities influence drug pharmacokinetics and dynamics. AKI is accompanied by therapeutic interventions that alter intrinsic metabolism which is in turn complicated by kidney replacement therapy (KRT). So metabolism and removal are both altered and constantly changing. Drug management in AKI is exceedingly complex and is only beginning to be understood. Thus, we approach this discussion in a physiological manner. Critically ill patients pass through phases of illness, sometimes rapidly, other times slowly. The recognition of the phases and the need to adjust medication administration strategies is crucial to improving outcomes. An early phase involving supraphysiologic kidney function may be contributory to therapeutic failures that result in the complication of later AKI and kidney function failure.
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Burns, Tom, e John Foot, eds. Basaglia's International Legacy: From Asylum to Community. Oxford University Press, 2020. http://dx.doi.org/10.1093/med/9780198841012.001.0001.
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Italian Law 180 of 1978 is probably the most radical Mental Health Act ever passed. It forbade the admission of any new patients to mental hospitals forthwith and called for the rapid closure of such institutions. The Law crowned the work of the charismatic Italian psychiatrist Franco Basaglia and his ‘Democratic Psychiatry’ movement. The Italian reforms resulted in arguably the lowest number of psychiatric beds in any developed country, and have been widely debated and emulated. They have been adopted enthusiastically by several Mediterranean and South American countries. However, the implementation of Law 180 was patchy, with critics both internally and internationally. This book brings together historians and clinicians, including Basaglia’s colleagues and followers, for the first time. These authors report on the responses to the reforms from over 15 countries. These range from exuberant implementation in Brazil and Italy, through partial and localized initiatives in several countries, through to outright rejection in the UK and USA. These responses reflect differences in clinical and practical realities, but also professional rivalries and often profound conceptual differences. This is a transnational history of psychiatric debates, reform, and psychiatric practice. The excitement of Basaglia’s thinking and the Italian reforms is captured, as are the inconsistencies in both his thinking and practice. Basaglia and the Italian movement did not arrive from nowhere, and its global influences are also examined. Basaglia’s radical human rights agenda was expressed through psychiatric reforms. His ambivalences engaged artists and thinkers as well as clinicians, and his legacy, as this book vividly demonstrates, is far from straightforward.
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Ayres Ferreira, Júlio César. Exame Físico Normal. Editorial Casa, 2022. http://dx.doi.org/10.55371/9786553990272.
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A presente obra tem como objetivo organizar, de forma sucinta, o exame físico do corpo humano. O livro é esquematizado seguindo as áreas de estudo da anatomia humana — dentre elas, a análise dos sinais vitais, exame físico dos aparelhos respiratório, neurológico, cardiovascular e digestivo. O material foca nos critérios essenciais para um exame físico uniforme, além de orientar e aprimorar as habilidades e conhecimentos básicos necessários para formação dos profissionais da saúde. É nosso desejo que o livro mostre a relevância do exame detalhado para o diagnóstico das patologias relacionadas a cada sistema do corpo. O exame físico é parte integrante da avaliação médica. Ele, em conjunto com a anamnese, é fundamental para um bom raciocínio clínico e, consequentemente, para um bom manejo e resolução da queixa do paciente. Dessa forma, faz-se de extrema importância que, desde o início da aprendizagem médica, suas etapas e particularidades sejam bem conhecidas. Todo esse universo que envolve a semiologia médica é bastante complexo e permeia todos os sistemas do corpo humano, ajudando o profissional a ter uma visão mais ampla sobre as enfermidades humanas. Assim, conhecer o exame físico normal é a primeira etapa para que se tenha mais rapidez na identificação dessas patologias. O livro que o leitor tem em mãos foi dividido em cinco núcleos que abordam, de forma simples e didática, as particularidades do exame físico normal, que vai desde conhecer os sinais vitais até os principais sistemas, como: cardiovascular, neurológico, respiratório e abdominal. Cada capítulo inicia-se com uma introdução ao básico do exame clínico daquele sistema. Em seguida, descreve-se de forma mais aprofundada, mas sem que se chegue ao nível especializado, todas as etapas necessárias para a avaliação semiológica dos órgãos que envolvem aquele sistema específico de forma que, ao final, seja possível ter uma visão completa do que compõe o exame normal. Este é um livro que foi escrito para mostrar que conhecer a semiologia básica faz e sempre fará parte da rotina de todo e qualquer profissional da saúde. Para que se conheça o complexo é necessário ter um excelente domínio do básico, e é isso que este livro proporciona de forma objetiva e sistemática.
Capítulos de livros sobre o assunto "BEMs rapides"
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Kleppner, Daniel. "Our Enduring Legacy from Otto Stern". In Molecular Beams in Physics and Chemistry, 97–117. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-63963-1_7.
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Faubel, Manfred. "Liquid Micro Jet Studies of the Vacuum Surface of Water and of Chemical Solutions by Molecular Beams and by Soft X-Ray Photoelectron Spectroscopy". In Molecular Beams in Physics and Chemistry, 597–630. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-63963-1_26.
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AbstractLiquid water, with a vapor pressure of 6.1 mbar at freezing point, is rapidly evaporating in high vacuum, rapidly cooling off by the evaporative cooling, and is freezing to ice almost instantly. Nevertheless, liquid water free vacuum surfaces can be prepared for short instances when injecting very small, fast flowing, liquid jets into high vacuum. They provide perfectly suited targets for molecular beams analysis of molecular evaporation of monomers and dimers from liquids. Also, the microjet technology allows ultrahigh vacuum studies of atomic scale liquid surface composition and electronic structures, as will be demonstrated by using highly focused Synchrotron radiation for EUV/XUV-photoelectron spectrocopy on a wide range of chemical solutions.
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Krassowska, Julita, e Marta Kosior-Kazberuk. "Serviceability Limit State of Fiber Reinforced Concrete Beams with BFPB Bars and Stirrups". In Springer Proceedings in Materials, 440–48. Cham: Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-72955-3_44.
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AbstractThe work analyzes the serviceability ultimate limit state of 4.5 m long fiber-reinforced concrete beams with basalt bars and stirrups (BFRP). On the basis of previous tests, deformations in beams with composite reinforcement are above acceptable values. Beams were made of concrete with basalt fibers to improve deformability, cracks resistance and deflection. The tests showed that the load capacity of beams reinforced with BFRP bars was lower than that of beams with steel reinforcement, resulting from different failure mechanisms of both beams. The failure of beams with BFRP reinforcement was rapid. Deformations in the concrete were reduced by using basalt fibers in the concrete. Increasing the stiffness of the structure with reinforcement with BFRP bars and stirrups using concrete with basalt fibers can meet the SLS requirements for limiting the deflection and cracking of concrete elements reinforced with them.
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Yuan, Chao, Feng Li, Min Wang e Fei Tian. "Research on Key Technology of Rapid Integrated Construction of Fully Prefabricated Rigid Frame Bridge". In Lecture Notes in Civil Engineering, 223–38. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-2532-2_19.
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AbstractBased on the reconstruction and expansion project of an expressway, a set of rapid construction technology for integrated erection of fully prefabricated rigid frame bridges is proposed, which solves the problems of unmatched work efficiency of each working face in the conventional integrated bridge erectors and long construction period of traditional suspension assembly technology. This method realizes the rapid construction of this type of bridges in highly urbanized areas. In this method, a new bridge girder integrated erection machine is used to synchronously install precast segmental beams, pier top blocks and precast pier column. At the same time, precast segmental beams near the middle pier are assembled by conventional cantilever assembly method, and the installation method of the precast segmental beams near the transition pier is optimized from the half span suspension assembly method to the cantilever assembly method by temporarily fixing the pier top block and arranging temporary prestressed tendons. This new integrated construction method improves the construction efficiency from 39.5d/unit to 32d/unit, and reduces the interference to traffic and environment.
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Mencek, H., e R. Soylu. "Systematic and Rapid Construction of Test Beds for Planar Mechanism". In New Trends in Mechanism and Machine Science, 277–85. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-09411-3_30.
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Ehsani, M. "Rapid repair of bridge beams and decks with prefabricated FRP panels". In Bridge Maintenance, Safety, Management, Digitalization and Sustainability, 4019–26. London: CRC Press, 2024. http://dx.doi.org/10.1201/9781003483755-474.
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Ries, Christoph, Virginia Wasem, Dorothea Karrer, Corinne John e Regine Eibl. "A New Approach for Rapid Development of Spodoptera frugiperda/BEVS-Based Processes". In Proceedings of the 21st Annual Meeting of the European Society for Animal Cell Technology (ESACT), Dublin, Ireland, June 7-10, 2009, 699–703. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-0884-6_111.
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Ries, Christoph, Corinne John e Regine Eibl. "A New Scale-Down Approach for the Rapid Development ofSf21/BEVS-Based Processes-A Case Study". In Single-Use Technology in Biopharmaceutical Manufacture, 207–13. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2011. http://dx.doi.org/10.1002/9780470909997.ch17.
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Huntley, David, Drew Rotheram-Clarke, Kelvin Sattler e David Elwood. "Surficial Geology and Geomorphology of the North Slide, Thompson River Valley, British Columbia, Canada: Application of Fundamental Geoscience Information to Interpretations of Geospatial Monitoring Results". In Progress in Landslide Research and Technology, 221–38. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-44296-4_10.
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AbstractOur study focuses on a slow-moving landslide in the Thompson River valley, south-central British Columbia, Canada, that has posed a hazard to the national railway transportation corridor since 1880. Real-time kinematic global navigation satellite systems, unoccupied aerial vehicles, and satellite synthetic aperture radar interferometry time-series show significant displacement encroaching on railway infrastructure. In this paper, geospatial relationships between landslide distribution and specific terrain features, and the environmental conditions triggering instability are determined from field-based geological observations. We describe how earth material stratigraphy, textures, and penetrative planar structures are important controls on sub-surface drainage, and how these factors influence the style, timing, and rate of slope displacement. West of the railway tracks, slide scarps extend across the toe slope, corresponding to narrow zones of high displacement, presence of perennial springs and seepage, and cutbank erosion along the river channel. Fluvial incision exposes weak, failure-prone units at the base of the fill sequence, and with ongoing channel migration promotes instability by altering landslide toe geometry. Currently, the zone of potential displacement does not extend upslope into the inactive (1880) main slide body, east of the tracks. Seasonal variations in hydrogeological conditions influence the spatial and temporal patterns of surface water and groundwater flow, in turn controlling the distribution of translational-rotational displacement of slide blocks, and rates of movement on reactivated shear surfaces that extend under Thompson River. Slope failure occurs along weak, sub-horizontal shear zones within poorly drained glaciolacustrine clay and silt units, overlain by rapidly drained glaciofluvial outwash gravel, and imperfectly drained till diamicton. River levels exert a complex control on landslide stability, influencing hydraulic gradients within the basal glaciolacustrine unit, particularly along rupture surfaces within it. Ground displacement occurs while river levels are at their lowest between February and March, before peak flows in June, or after July until December while storm-fed river levels progressively lower to the next winter minimum. Groundwater levels remain elevated in the slide body throughout the year, contained in porous gravel and sand beds, and along brittle fractures and sub-horizonal shear zones in silt-clay varve beds. Geospatial and temporal change-detection monitoring of active landslides and at-risk infrastructure, when benchmarked with terrain and hydrogeological observations, is a cost-effective hazard management practice that provides important geoscience information to help develop appropriate early warning, mitigation, adaptation, and risk reduction measures.
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Franke, Jörg, Peter Wasserscheid, Thorsten Ihne, Peter Lamp, Jürgen Guldner e Oliver Zipse. "The Power of Technological Innovation". In Road to Net Zero, 215–64. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-42224-9_8.
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AbstractAchieving the urgent need for rapid decarbonization to meet the 1.5 °C target requires disruptive technological change. In the automotive industry, technological progress is closely linked to improved sustainability, and sustainability goals drive the need for technological innovation. However, new technologies in the mobility sector are fraught with uncertainties that challenge both original equipment manufacturers (OEMs) and their stakeholders, such as suppliers, customers, and policy-makers. Therefore, this chapter focuses on the technical, economic, and environmental evaluation of alternative powertrain concepts and the management of uncertainties associated with emerging technological innovation as part of the broader transition to net zero.Electric mobility plays a central role in the sustainability transition and is characterized by a high degree of variance. Battery electric vehicles (BEVs) are expected to dominate private transport in the future due to their greenhouse gas and pollutant-free operation and high efficiency. In addition to charging infrastructure, the technical challenges currently lie primarily in cell chemistry and power electronics. Advances in battery technology and infrastructure electrification will help eliminate the range problem in the future. Another important future fuel is hydrogen. One application is the fuel cell vehicle, which combines the advantages of a chemical energy carrier with high gravimetric energy density with those of an electrical energy converter. Hydrogen also plays an important role as an energy carrier for specific energy supply processes in manufacturing processes and simplifies the transport of regeneratively generated energy. In addition, hybrid vehicles are a transitional technology, and alternative fuel internal combustion engines can contribute to the decarbonization of the existing fleet and to specific applications.This chapter assesses the performance of alternative powertrains; highlights the interrelationship between powertrain systems, energy ecosystems, and sustainability goals; and identifies future research directions for electric and hydrogen mobility.
Trabalhos de conferências sobre o assunto "BEMs rapides"
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Ye, Jiachi, Haoyan Kang, Belal Jahannia, Chandraman Patil, Hao Wang, Elham Heidari, Navid Asadizanjani e Hamed Dalir. "Using Hybrid Optical-Electronic Neural Network for Demultiplexing Multiplexed Orbital Angular Momentum Beams". In 2024 IEEE Research and Applications of Photonics in Defense Conference (RAPID), 1–2. IEEE, 2024. http://dx.doi.org/10.1109/rapid60772.2024.10646945.
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Hooi, Chin. "Design, Rapid Prototyping and Testing of a Ducted Fan Micro-Quadcopter". In Vertical Flight Society 70th Annual Forum & Technology Display, 1–10. The Vertical Flight Society, 2014. http://dx.doi.org/10.4050/f-0070-2014-9429.
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This paper discusses recent results toward the design, rapid prototyping and testing of a ducted microquadcopter. Mobility and convenience objectives of this work dictate that the quadcopter must fit into a pocket, be capable of shooting high-definition videos and pictures, be controllable through a smartphone application, have a rotor diameter of 7cm and weigh approximately 300 g. Previous designs have rotor dimensions of 25 cm or more as well as airframe width and length of 75 cm and above. Aerodynamically, the ducted fan design is analyzed through Momentum Theory and Blade Element Momentum Theory (BEMT) to determine its contribution toward improved performance in hover, axial climb, axial descent and forward flight. The ducted fan design can be optimized for lower power consumption of up to 30% or smaller diameter than an open rotor and improves hover performance most significantly. Individual components, including the upper ducted and lower airframe were fabricated using composite layup methods. Microrotors as well as ducted fan molds were designed and built through three-dimensional (3D) Printing methods, including the Fused Deposit Modeling (FDM) and the PolyJet (PJ) method. Careful attention was taken to patch the duct lips with composites and sanding them to ensure smoothness. It was found that microrotors have to have at least a 4% thickness-to-chord ratio in order to be structurally sound. For the FDM method, the microrotors have to be printed with the blade plane perpendicular to the print bed and the blades oriented such that the blades have the strongest structural layout possible. For four and two blades, the best configurations are having the blades at having the blades at 60° and 0° (horizontal) to the print bed respectively. The PJ method, is capable of printing highly accurate microrotors flat on the print bed. However, they are less stiff and tend to flap more and structurally deform under exposure to ultraviolet (UV) and heat sources, hence making them more suitable for short term usage. Test results indicate that the FDM rotors produce more thrust than PJ rotors and have a lower torque-to-thrust ratio due to the fact that PJ rotors are less stiff. This in turn leads to excessive flapping and more susceptibility to flutter, which requires thicker blades at the expense of higher profile drag. Likewise, PJ rotors can be designed for higher thrust and lower torque-to-thrust ratio by incorporating constant chord blades at lower pitch angles, yet maintaining the same diameter and solidity as their variable chord counterparts.
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Aguirre, Mikel, Antoine Riols-Fonclare e François Richez. "Aeroelastic Analysis with Rapid Methods of the Double-swept ERATO Blade with an Homogeneous Structure in Hover Flight". In Vertical Flight Society 80th Annual Forum & Technology Display, 1–15. The Vertical Flight Society, 2024. http://dx.doi.org/10.4050/f-0080-2024-1342.
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This article presents aeroelastic analysis of the ERATO blade with double-swept design and an homogenised structure, using both computationally intensive and rapid aerodynamics solvers coupled with a projection-based reduced-order model (ROM) for the structure. The study focuses on investigating the impact of blade flexibility on aerodynamic performance during hover flight, and comparing with experimental data. In terms of modelling, the ROM allows for efficient computation of structural displacements, while capturing the non-linear physics and the complex structural response induced by the double-swept configuration. The aerodynamic analysis incorporates different solvers including among others Computational Fluid Dynamics (CFD) with elsA, Vortex Particle Method (VPM) and Blade Element Momentum Theory (BEMT). This multi-solver approach is employed to assess the capability of fast aerodynamic methods to reproduce the desired flow, coupling properties and flight performance. The coupling methods employed such as field transfers and mesh deformation are rather classical but were adapted. First, results highlight the need of aeroelastic coupled analysis to model the ERATO blade in hover. Second, the VPM is proven to be a valid method for reproducing the studied flight condition offering a good compromise between the computational cost and accuracy. Third, the proposed VPM/ROM coupling is validated with respect to the reference CFD/ROM. Finally, this article contributes to evaluate a wide range of methodologies and to propose an alternative method for predicting the rotorcraft blades performance and for assessing the effect of the aeroelastic coupling on such performance. Future work is needed to characterize in more details the aeroelastic behaviour of the ERATO blades with a realistic structural model for hover and in forward-flight, for which the flow is intrinsically unsteady.
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Free, J., K. Morgan, J. K. Miller, Kunjian Dai, R. J. Watkins e E. G. Johnson. "Rapidly Reconfigurable Pulsed Higher Order Bessel Beams". In Frontiers in Optics. Washington, D.C.: OSA, 2020. http://dx.doi.org/10.1364/fio.2020.fw1a.5.
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Sivasubramanian, Balaji, e Daewon Kim. "Effects of Rapid Change in Temperature on Ultrasonic Guided Lamb Wave Propagation". In ASME 2013 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/smasis2013-3173.
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The usage of ultrasonic guided Lamb wave approach in structural health monitoring has been prevalent and proven to be an effective method. During flight, aircraft or spacecraft structures sometimes experience rapid temperature changes. The propagation of guided Lamb waves can be affected by these abrupt changes. In this paper, the effects of rapid temperature variation, due to which a sharp temperature gradient is achieved, on the propagation of guided Lamb waves through aluminum and composite beams are compared. The heating and cooling cycles for gradual temperature changes are firstly obtained for comparison. An abrupt change in the temperature is brought out by heating the beam to an elevated temperature and rapidly cooling it using liquid nitrogen. The design guidelines for the experimental setup used in the research are provided. The effects of rapid change in the temperature on the piezoelectric wafer active sensors (PWAS) are measured. Two different adhesives between the PWAS sensors and the beams are tested and the results obtained from the experiments are discussed.
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Gregory, Stephen. "Monolayer Film Properties Measurements Using High Q Graphite Fibers". In Microphysics of Surfaces, Beams, and Adsorbates. Washington, D.C.: Optica Publishing Group, 1987. http://dx.doi.org/10.1364/msba.1987.wb2.
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Although the field of surface analysis continues to grow rapidly, it remains true that mechanical properties of films are not easily studied. Indeed, when the films are one to a few monolayers thick, the very definitions of mechanical properties are in question.
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Rothschild, M., J. H. C. Sedlacek e D. J. Ehrlich. "Laser Photochemical Etching of Molybdenum and Tungsten Thin Films by Surface Halogenation*". In Microphysics of Surfaces, Beams, and Adsorbates. Washington, D.C.: Optica Publishing Group, 1987. http://dx.doi.org/10.1364/msba.1987.mb4.
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Laser direct writing techniques, employing rapidly scanned microchemical deposition and etching reactions, are of importance for advanced nonlithographic fabrication of microelectronics. One class of applications employs these techniques for fine-line in situ alteration of conducting films as a last step in fabrication. Of particular importance for these applications is laser-induced patterning of Mo and W, which are becoming widely used materials for metallization of both Si and GaAs microelectronic devices.
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Liang, Yongdong, Wei Li, Jue Zhang, Yan Wu, Wei Kai e Maosheng Yao. "Rapid allergen inactivation using atmospheric pressure cold plasma". In 2014 IEEE 41st International Conference on Plasma Sciences (ICOPS) held with 2014 IEEE International Conference on High-Power Particle Beams (BEAMS). IEEE, 2014. http://dx.doi.org/10.1109/plasma.2014.7012667.
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Dreyfus, R. W., R. Walkup e J. M. Jasinski. "Laser Interferometry and Laser Induced Fluorescence Studies of Laser Etching". In Microphysics of Surfaces, Beams, and Adsorbates. Washington, D.C.: Optica Publishing Group, 1985. http://dx.doi.org/10.1364/msba.1985.mb5.
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Excimer laser ablation of solids with laser power densities in the range 106 to 109 W/cm2 is becoming increasingly important in laser processing of materials for microelectronics. The ablation process produces an intense plume of gas phase material which expands rapidly away from the ablated surface. We report on real time interferometric measurements of free electron density and laser induced fluorescence studies of atoms and molecules in the plume, with the objective of understanding the dynamics of material ablation.
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Chen, Da-Ming, Y. F. Xu e W. D. Zhu. "Damage Identification Using a Continuously Scanning Laser Doppler Vibrometer System". In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-67293.
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A continuously scanning laser Doppler vibrometer (CSLDV) system is capable of rapidly obtaining spatially dense operating deflection shapes (ODSs) by continuously sweeping a laser spot from the system over a structure surface. This paper presents a new damage identification methodology for beams that uses their ODSs under sinusoidal excitation obtained by a CSLDV system, where baseline information of associated undamaged beams is not needed. A curvature damage index (CDI) is proposed to identify damage near a region with high values of the CDI at an excitation frequency. The CDI uses the difference between curvatures of ODSs associated with ODSs that are obtained by two different CSLDV measurement methods, i.e., demodulation and polynomial methods; the former provides rapid and spatially dense ODSs of beams, and the latter provides ODSs that can be considered as those of associated undamaged beams. Phase variables are introduced to the two methods for damage identification purposes. The proposed damage identification methodology was experimentally validated on a beam with damage in the form of machined thickness reduction. The damage and its region were successfully identified in neighborhoods of prominent peaks of CDIs at different excitation frequencies.
Relatórios de organizações sobre o assunto "BEMs rapides"
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Hefetz, Abraham, e Justin O. Schmidt. Use of Bee-Borne Attractants for Pollination of Nonrewarding Flowers: Model System of Male-Sterile Tomato Flowers. United States Department of Agriculture, outubro de 2003. http://dx.doi.org/10.32747/2003.7586462.bard.
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The use of bee natural product for enhancing pollination is especially valuable in problematic crops that are generally avoided by bees. In the present research we attempted to enhance bee visitation to Male Sterile (M-S) tomato flowers generally used in the production of hybrid seeds. These flowers that lack both pollen and nectar are unattractive to bees that learn rapidly to avoid them. The specific objects were to elucidate the chemical composition of the exocrine products of two bumble bee species the North American Bombus impatiens and the Israeli B. terrestris. Of these, to isolate and identify a bee attractant which when sprayed on M-S tomato flowers will enhance bee visitation, and to provide a procedure of the pheromone application regime. During the research we realized that our knowledge of B. impatiens is too little and we narrowed the objective to learning the basic social behavior of the bees and the pattern of foraging in a flight chamber and how it is affected by biogenic amines. Colonies of B. impatiens are characterized by a high number of workers and a relatively small number of queens. Size differences between queens and workers are pronounced and the queen seems to have full control over egg laying. Only about 9% of the workers in mature colonies had mature oocytes, and there were no signs of a "competition phase" as we know in B. terrestris. Queens and workers differ in their exocrine bouquet. Queen's Dufour's gland possesses a series of linear, saturated and unsaturated hydrocarbons whereas that of workers contains in addition a series of wax-type esters. Bees were trained to either visit or avoid artificially scented electronic flowers in a flight chamber. Since bee also learned to avoid scented non-rewarding flowers we attempted to interfere with this learning. We tested the effect of octopamine, a biogenic amine affecting bee behavior, on the choice behavior of free-flying bumblebees. Our results show that octopamine had no significant effect on the bees' equilibrium choice or on the overall rate of the behavioral change in response to the change in reward. Rather, octopamine significantly affected the time interval between the change in reward status and the initiation of behavioral change in the bee. In B. terrestris we studied the foraging pattern of the bees on tomato flowers in a semi commercial greenhouse in Yad Mordechai. Bee learned very quickly to avoid the non- rewarding M-S flowers, irrespective of their arrangement in the plot, i.e., their mixing with normal, pollen bearing flowers. However, bees seem to "forget" this information during the night since the foraging pattern repeats itself the next morning. Several exocrine products were tested as visitation enhancers. Among these, tarsal gland extracts are the most attractive. The compounds identified in the tarsal gland extract are mostly linear saturated hydrocarbons with small amounts of unsaturated ones. Application was performed every second day on leaves in selected inflorescences. Bee visitation increased significantly in the treated inflorescences as compared to the control, solvent treated. Treatment of the anthers cone was more effective than on the flower petals or the surrounding leaves. Methanol proved to be a non-flower-destructive solvent. We have shown that bumble bees (B. terrestris) can be manipulated by bee-borne attractants to visit non-rewarding flowers. We have further demonstrated that the bees learning ability can be manipulated by applying exogenously octopamine. Both methods can be additively applied in enhancing pollination of desired crops. Such manipulation will be especially useful in tomato cultivation for hybrid seed production.
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Bank, Lawrence C., Anthony J. Lamanna, James C. Ray e Gerardo I. Velazquez. Rapid Strengthening of Reinforced Concrete Beams with Mechanically Fastened, Fiber-Reinforced Polymeric Composite Materials. Fort Belvoir, VA: Defense Technical Information Center, março de 2002. http://dx.doi.org/10.21236/ada400415.
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Renk, Timothy, Bob Turman, Donna Senft, Neil Sorensen, Regan Stinnett, John Greenly, Michael Thompson e Rudolph Buchheit. Rapid Melt and Resolidification of Surface Layers Using Intense, Pulsed Ion Beams Final Report. Office of Scientific and Technical Information (OSTI), outubro de 1998. http://dx.doi.org/10.2172/703.
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Bloch, G., e H. S. Woodard. regulation of size related division of labor in a key pollinator and its impact on crop pollination efficacy. Israel: United States-Israel Binational Agricultural Research and Development Fund, 2021. http://dx.doi.org/10.32747/2021.8134168.bard.
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Despite the rapid increase in reliance on bumble bees for food production and security, there are many critical knowledge gaps in our understanding of bumble bee biology that limit their colony production, commercial management, and pollination services. Our project focuses on the social, endocrine, and molecular processes regulating body size in the two bumble bee species most important to agriculture: Bombus terrestris in Israel, and B. impatiens in the USA. Variation in body size underline both caste (queen/worker) differentiation and division of labor among workers (foragers are typically larger than nest bees), two hallmarks of insect sociality which are also crucial for the commercial rearing and crop pollination services of bumble bees. Our project has generated several fundamental new insights into the biology of bumble bees, which can be integrated into science-based management strategies for commercial pollination. Using transcriptomic and behavioral approaches we show that in spite of high flexibility, task performance (brood care or foraging) in bumble bee colonies is associated with physiological variation and differential brain gene expression and RNA editing patterns. We further showed that interactions between the brood, the queen, and the workers determine the developmental program of the larva. We identified two important periods. The first is a critical period during the first few days after hatching. Larvae fed by queens during this period develop over less days, are not likely to develop into gynes, and commonly reach a smaller ultimate body size compared to workers reared mostly or solely by workers. The facial exocrine (mandibular and hypopharangeal) glands are involved in this queen effect on larva development. The second period is important for determining the ultimate body size which is positively regulated by the number of tending workers. The presence of the queen during this stage has little, if at all, influence. We further show that stressors such as agrochemicals that interfere with foraging or brood care specific processes can compromise bumble bee colony development and their pollination performance. We also developed new technology (an RFID system) for automated collection of foraging trip data, for future deployment in agroecosystems. In spite of many similarities, our findings suggest important differences between the Eurasian model species (B. terrestris) and the North American model species (B. impatiens) that impact how management strategies translate across the two species. For example, there is a similar influence of the queen on offspring body size in both species, but this effect does not appear to be mediated by development time in B. impatiens as it is in B. terrestris. Taken together, our collaboration highlights the power of comparative work, to show that considerable differences that exist between these two key pollinator species, and in the organization of young bumble bee nests (wherein queens provide the majority of care and then transition away from brood care) relative to later stages of nest development.
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Bhatt, Mihir R., Shilpi Srivastava, Megan Schmidt-Sane e Lyla Mehta. Key Considerations: India's Deadly Second COVID-19 Wave: Addressing Impacts and Building Preparedness Against Future Waves. Institute of Development Studies (IDS), junho de 2021. http://dx.doi.org/10.19088/sshap.2021.031.
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Since February 2021, countless lives have been lost in India, which has compounded the social and economic devastation caused by the second wave of COVID-19. The sharp surge in cases across the country overwhelmed the health infrastructure, with people left scrambling for hospital beds, critical drugs, and oxygen. As of May 2021, infections began to come down in urban areas. However, the effects of the second wave continued to be felt in rural areas. This is the worst humanitarian and public health crisis the country has witnessed since independence; while the continued spread of COVID-19 variants will have regional and global implications. With a slow vaccine rollout and overwhelmed health infrastructure, there is a critical need to examine India's response and recommend measures to further arrest the current spread of infection and to prevent and prepare against future waves. This brief is a rapid social science review and analysis of the second wave of COVID-19 in India. It draws on emerging reports, literature, and regional social science expertise to examine reasons for the second wave, explain its impact, and highlight the systemic issues that hindered the response. This brief puts forth vital considerations for local and national government, civil society, and humanitarian actors at global and national levels, with implications for future waves of COVID-19 in low- and middle-income countries. This review is part of the Social Science in Humanitarian Action Platform (SSHAP) series on the COVID-19 response in India. It was developed for SSHAP by Mihir R. Bhatt (AIDMI), Shilpi Srivastava (IDS), Megan Schmidt-Sane (IDS), and Lyla Mehta (IDS) with input and reviews from Deepak Sanan (Former Civil Servant; Senior Visiting Fellow, Centre for Policy Research), Subir Sinha (SOAS), Murad Banaji (Middlesex University London), Delhi Rose Angom (Oxfam India), Olivia Tulloch (Anthrologica) and Santiago Ripoll (IDS). It is the responsibility of SSHAP.