Academic literature on the topic 'Fragmentation secondaire'
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Journal articles on the topic "Fragmentation secondaire":
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Dufour, Guillaume, Marc Massot, and Philippe Villedieu. "Étude d'un modèle de fragmentation secondaire pour les brouillards de gouttelettes." Comptes Rendus Mathematique 336, no. 5 (March 2003): 447–52. http://dx.doi.org/10.1016/s1631-073x(03)00067-0.
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Lessard, Claude. "Égalité des chances et stratification dans le champ scolaire : quid de l’équité du système d’éducation ?" Éthique en éducation et en formation, no. 6 (April 29, 2019): 41–61. http://dx.doi.org/10.7202/1059242ar.
Abstract:
Le système d’éducation québécois, comme la société qui l’entoure, se fragmente : d’abord, en fonction des facteurs sociaux traditionnels — notamment, le revenu et l’éducation des parents —, ensuite, en fonction de la multiplication de modèles socioculturels. Dans le champ de l’enseignement primaire et secondaire, la première fragmentation s’exprime par la montée de l’enseignement privé, notamment dans les centres urbains; la seconde fragmentation se manifeste, au sein du réseau public, par la multiplication et la variété des projets particuliers, conçus pour retenir des élèves de milieux favorisés, mais aussi pour permettre à des groupes sociaux de transmettre à leurs enfants une éducation distinctive. Ce texte analyse la manifestation de cette double fragmentation dans le champ éducatif et la contextualise dans le cadre de grands changements sociétaux. Nous soutenons qu’ainsi mis sur les rails de la concurrence, le système scolaire québécois est de plus en plus stratifié ou qu’il a plusieurs vitesses. Nous explorons quelques politiques publiques qui permettraient la sortie d’une situation difficile à dépasser.
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Hingrat, Yves, and F. Feer. "Effets de la fragmentation forestière sur l’activité des coléoptères coprophages : dispersion secondaire des graines en Guyane française." Revue d'Écologie. Supplément 57, no. 8 (2002): 165–79. http://dx.doi.org/10.3406/revec.2002.6243.
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Netter, Julien. "Ouverture de l’école et inégalités. Constats et perspectives." Éducation et sociétés 50, no. 2 (September 7, 2023): 17–31. http://dx.doi.org/10.3917/es.050.0017.
Abstract:
Dans L’évolution pédagogique en France , Durkheim estime que l’instabilité chronique que l’enseignement secondaire connaît au début du XX e siècle depuis plusieurs décennies traduit la difficulté à trouver le “changement d’esprit et d’orientation qui se trouve nécessaire”. Un constat étonnamment similaire peut être dressé pour l’école primaire française du début du XXI e siècle, en proie à des réformes parfois contradictoires qui se succèdent rapidement. Cette réflexion interroge la difficulté de l’école, dans cette situation, à définir un horizon collectif permettant de se saisir de la question persistante des inégalités scolaires. L’article revient d’abord sur l’évolution générale de l’école vers une plus grande fragmentation, liée à l’accumulation de dispositifs permettant la juxtaposition d’acteurs non coordonnés et de conceptions de l’apprentissage peu discutées. Il cherche ensuite à montrer que le fait de penser l’école en termes de dispositifs amène à négliger la question des pratiques pédagogiques, particulièrement délaissées en France.
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Kodjo, Yawo, Jean-Robert Rwenge Mburano, and Hamidou Kone. "Utilisation des Services Obstétricaux Modernes au Togo: Approche par les Modèles Mixtes." European Scientific Journal, ESJ 18, no. 40 (December 31, 2022): 10. http://dx.doi.org/10.19044/esj.2022.v18n40p10.
Abstract:
Plusieurs études révèlent que près de 80 % des décès maternels pourraient être évités si les femmes avaient fait un recours adéquat aux soins obstétricaux modernes (Adiko et al., 2018). Au Togo, seulement 33% des femmes ont fait un recours adéquat aux consultations prénatales et 64% ont fait recours à l’accouchement moderne en 2017 (Institut Nationale de Statistique et des Etudes Démographiques(INSEED), 2017). Des modèles mixtes en particulier de la régression logistique multiniveau appliqués aux données de l’enquête par grappes à indicateurs multiples (2017), il ressort que, les femmes faisant recours adéquat aux consultations prénatales uniquement, pratiquaient la contraception moderne, sans union ou en union monogame, vivaient dans des ménages dirigés par une personne ayant un niveau d’instruction secondaire ou plus. Elles habitent dans les communautés à degrés de modernité sanitaire élevé et de fragmentation religieuse homogène. Celles qui ont fait recours uniquement à l’accouchement moderne ont une assurance santé, sont plus épanouies et dirigées par une personne du groupe ethnique Adja/Ewé. Elles résident dans les ménages non loués. Ce sont elles qui habitent dans des communautés plus riches. Tandis que celles qui font les deux recours sont des primipares, plus exposées aux médias, résidant dans un ménage à niveau de vie élevé et dirigé par un chef catholique ou musulman. Au Togo, il serait pertinent d’agir sur le recours adéquat aux consultations prénatales en rendant plus disponibles les soins et sur le recours à l’accouchement moderne par la sensibilisation sur son l’utilité.
Several studies show that nearly 80 per cent of maternal deaths could be prevented if women had made adequate use of modern obstetric care (Adiko and al., 2018). In Togo, only 33% of women made adequate use of antenatal consultations and 64% resorted to modern childbirth in 2017 (INSEED, 2017). Mixed models in particular the multilevel logistic regression on data from the Multiple Indicator Cluster Survey (2017), it appears that women making adequate use of antenatal consultations only, has used modern contraception, without a union or in a monogamous union, lived in households headed by a person with secondary education or higher. They live in communities with high degrees of sanitary modernity and homogeneous religious fragmentation. Those who rely solely on modern childbirth have health insurance, are more fulfilled and are led by someone from the Adja/Ewé ethnic group. They reside in non-rented households. They are the ones who live in wealthier communities. While those who make both appeals are primiparous, more exposed to the media, residing in a household with a high standard of living and headed by a chief Catholic or Muslim religious. In Togo, it would be relevant to act on the appropriate use of antenatal cares by making care more available and on the use of modern childbirth by raising public awareness of its usefulness.
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Raftery, MJ, and JH Bowie. "The Collision-Induced Dissociations of Deprotonated Amines in the Gas Phase." Australian Journal of Chemistry 41, no. 9 (1988): 1477. http://dx.doi.org/10.1071/ch9881477.
Abstract:
The major collision-induced fragmentations of deprotonated primary and secondary amines are best rationalized as proceeding through the intermediacy of ion complexes. For example, the characteristic fragmentation of deprotonated ethylamine isMeCH2NH- → [Me-(CH2=NH)] → CH2N- + CH4 Secondary alkylamines behave in a similar fashion. The occurrence of proton transfer as a prelude to fragmentation is rare: the only example observed in this study is the probable reaction PhNEt →→ PhNHCHMe → [(PhNH=CH)Me-] → C7H6N- + CH4 which is preceded or accompanied by proton transfer between the methylene and phenyl substituents. Deprotonated aniline undergoes specific elimination of CNH from the 1-position to form the cyclopentadienyl anion. Finally, retro reactions are observed for the piperazine anion, e.g. HN(CH2CH2)2N → -CH2CH2N=CH2+CH2NH
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Oz, Ibrahim Ilker, Sevil Ilikhan, Muammer Bilici, Hatice Harmansa, Kemal Karakaya, and Yucel Ustundag. "Bezoar-Related Ileus Secondary to Endoscopic Fragmentation." Istanbul Medical Journal 16, no. 4 (January 8, 2016): 155–57. http://dx.doi.org/10.5152/imj.2015.42104.
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Rudling, Adriana. "What’s Inside the Box? Mapping Agency and Conflict within Victims’ Organizations." International Journal of Transitional Justice 13, no. 3 (September 26, 2019): 458–77. http://dx.doi.org/10.1093/ijtj/ijz025.
Abstract:
Abstract∞ This article provides a better understanding of victims’ individual-level agency and their differences in terms of transitional justice preferences and capabilities by inquiring into intra-organizational conflict. While it is primarily conceptual, it combines secondary literature with case study material from Colombia and Panama, converging on Latin America as a geographical area and the crime of forced disappearance. Tracing the evolution of the 2004/2005 fragmentation of the Colombian Association of Relatives of Detained Disappeared Persons, it argues that victims’ collective action and perceived homogeneity is a performance that builds on much internal negotiation between members. When deliberations have clear winners, they end in adjustments of the mission statement of the group, purges and voluntary member withdrawal, but fragmentations result from situations where the leaders of opposing coalitions are evenly matched and their proposals equally engaging to peers.
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Botrill, Andrew R., Anastassios E. Giannakopulos, Allen Millichope, Ken S. Lee, and Peter J. Derrick. "Combination of Time-of-Flight Mass Analysers with Magnetic-Sector Instruments: In-Line and Perpendicular Arrangements. Applications to Poly(Ethylene Glycol) with Long-Chain end Groups." European Journal of Mass Spectrometry 6, no. 2 (April 2000): 225–32. http://dx.doi.org/10.1255/ejms.341.
Abstract:
High-energy collision-induced dissociation has been shown to provide extensive and detailed structural information on poly(ethylene glycol) with palmitoyl end-groups. Fragmentation within the end-groups provides direct information on their structures. Both in-line time-of-flight (TOF) and orthogonal TOF have been used for the measurement of fragment ions. Use of TOF as the second stage of mass spectrometry has facilitated exploitation of the pulsed method of ionisation matrix-assisted laser desorption/ionisation (MALDI). The orthogonal TOF instrument is used with a liquid secondary-ion mass spectrometry source. The laboratory-frame collision energies were different for in-line and orthogonal TOF, being 8–12 keV in the former and 800 eV in the latter. The tandem mass spectra were similar for the in-line experiment with either He or Xe collision gas and the orthogonal experiment with Xe. Mechanisms proposed for the fragmentations involve homolytic cleavage (C–H and backbone bonds) and invoke non-ergodicity.
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Phillips, Vaughan T. J., Sachin Patade, Julie Gutierrez, and Aaron Bansemer. "Secondary Ice Production by Fragmentation of Freezing Drops: Formulation and Theory." Journal of the Atmospheric Sciences 75, no. 9 (August 16, 2018): 3031–70. http://dx.doi.org/10.1175/jas-d-17-0190.1.
Abstract:
Abstract A numerical formulation is provided for secondary ice production during fragmentation of freezing raindrops or drizzle. This is obtained by pooling laboratory observations from published studies and considering the physics of collisions. There are two modes of the scheme: fragmentation during spherical drop freezing (mode 1) and during collisions of supercooled raindrops with more massive ice (mode 2). The empirical scheme is for atmospheric models. Microphysical simulations with a parcel model of fast ascent (8 m s−1) between −10° and −20°C are validated against aircraft observations of tropical maritime deep convection. Ice enhancement by an order of magnitude is predicted from inclusion of raindrop-freezing fragmentation, as observed. The Hallett–Mossop (HM) process was active too. Both secondary ice mechanisms (HM and raindrop freezing) are accelerated by a positive feedback involving collisional raindrop freezing. An energy-based theory is proposed explaining the laboratory observations of mode 1, both of approximate proportionality between drop size and fragment numbers and of their thermal peak. To illustrate the behavior of the scheme in both modes, the glaciation of idealized monodisperse populations of drops is elucidated with an analytical zero-dimensional (0D) theory treating the freezing in drop–ice collisions by a positive feedback of fragmentation. When drops are too few or too small (≪1 mm), especially at temperatures far from −15°C (mode 1), there is little raindrop-freezing fragmentation on realistic time scales of natural clouds, but otherwise, high ice enhancement (IE) ratios of up to 100–1000 are possible. Theoretical formulas for the glaciation time of such drop populations, and their maximum and initial growth rates of IE ratio, are proposed.
Dissertations / Theses on the topic "Fragmentation secondaire":
1
Crawley, George. "Granulométrie des suspensions de particules fines par mesures turbidimétriques spectrales. Application à l'étude de la fragmentation des cristaux dans une cuve agitée." Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 1994. http://tel.archives-ouvertes.fr/tel-00843935.
Abstract:
Les propriétés physiques, chimiques, mécaniques et rhéologiques des matériaux pulvérulents dépendent de manière notable de leur état granulaire. Ceci justifie la multiplicité des techniques granulométriques. Du fait de leur conception et de leur technologie, la plupart de ces techniques requièrent une préparation ou un prélèvement qui peuvent altérer l'état granulaire de l'échantillon. Une sonde granulométrique utilisable in situ présente donc un intérêt majeur, autant pour caractériser et contrôler en continu un procédé que pour obtenir des informations sur un mécanisme. C'est dans ce but que nous avons développé une sonde turbidimétrique spectrale. En effet, les mesures de turbidité sont réalisables par un capteur de petites dimensions utilisable in situ et relié à un ensemble spectrophotométrie. La distribution granulométrique d'une poudre en suspension est théoriquement accessible par le calcul à partir de son spectre de turbidité. Différents algorithmes et leurs logiciels correspondants ont été conçus ou mis au point Les possibilités et les limites de la turbidimétrie comme méthode granulométrique sont définies à partir de spectres mesurés ou simulés. Le domaine de sensibilité maximale ainsi déterminé est de [0.1-10 µm] pour les diamètres et inférieur à 10-3pour la fraction volumique. Ces contraintes destinent la méthode aux applications en milieu peu chargé. La deuxième partie de ce travail est consacrée à l'étude particulière d'un phénomène de fragmentation de cristaux de suIfate de potassium dans un cristallisoir agité. L'objectif visé est double : prouver la faisabilité de la méthode pour suivre un processus réel dans un réacteur de type industriel et caractériser in situ un phénomène essentiel en cristallisation puisqu'il est responsable de la formation de la plupart des germes. Une telle étude en ligne n'a jamais été réalisée jusqu'à présent. Les paramètres du système sont la vitesse de rotation de l'agitateur, la nature du milieu liquide, le nombre et le diamètre des grains introduits initialement (grain "parents"). L'augmentation de la turbidité constatée expérimentalement est due à la production de petits fragments dont la taille est calculée grâce au logiciel évoqué plus haut. Dans l'éthanol, ces fragments microniques restent libres alors que dans une solution aqueuse saturée ils s'agglomèrent. Les influences de la plupart des paramètres sont expliquées. Le capteur turbidimétrique conçu et validé dans ce travail a été également appliqué avec succès à l'étude d'autres processus intervenant en cristallisation et en particulier la germination primaire, la germination secondaire et I'agglomération.
2
Liu, Yubo. "Characterisation of block cave mining secondary fragmentation." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/58516.
Abstract:
Block cave mining is a widely employed mining method around the world due to its low operating cost. One of the key factors that affects block caving mine’s productivity is fragmentation; accordingly, significant efforts have been made and are currently being made to study fragmentation processes, including the use of numerical modelling and remote sensing techniques. It is desirable to develop fragmentation models that could be used to provide reliable estimates of the range and distribution of the sizes of the rock blocks expected to be induced by caving. In the context of block and panel cave mining, fragmentation processes are characterised as:
i) In-situ (natural) Fragmentation: in-situ blocks that are naturally present within the rock mass before any mining activity takes place. They are defined by the pre-existing discontinuities.
ii) Primary Fragmentation: blocks that separates from the cave back as the undercut is mined and caving is initiated.
iii) Secondary Fragmentation: fragmentation that occurs as the blocks move down through the ore column to the drawpoints.
The main goal of this thesis is to attempt to establish a relationship between in-situ fragmentation and secondary fragmentation. This is achieved by:
i) Measuring secondary fragmentation observed at the drawpoints. Digital image processing is employed in this process, using WipFrag (WipWare, 2014) and PortaMetrics (MotionMetrics, 2015).
ii) Using Discrete Fracture Networks (DFN) to generate in-situ fragmentation curves based on data mapped from boreholes and drifts. The code FracMan (Golder, 2014) is used to generate the DFN model and the fragmentation curves. Additionally, the height of draw data from code PCBC (Systems, 2015) is used to establish a relationship between modelled in-situ fragmentation and measured secondary fragmentation.
iii) This research is considered to benefit the assessment of block caving fragmentation specifically the estimate of oversizes (hang-ups) at draw columns. Also as a part of the on-going project Cave-to-Mill (Nadolski, et al., 2015) conducted at UBC Mining, this research will feed into the further analysis of Cave - to - Mill study.Applied Science, Faculty of
Mining Engineering, Keevil Institute of
Graduate
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Wei, Linkai. "Development of a new steam explosion model for the MC3D software." Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0097.
Abstract:
L'explosion de vapeur est l'un des phénomènes les plus critiques et complexes qui peuvent se produire lors d'un accident grave dans une centrale nucléaire. Le code MC3D est reconnu comme une référence pour l'évaluation de ce phénomène. Ce phénomène explosif est analogue à une détonation. L'explosion est due à la fragmentation du combustible fondu, au passage de l'onde de choc et à la libération très rapide de l'énergie associée. Cependant, les mécanismes précis du processus de pressurisation sont très incertains et ont fait l'objet de travaux réalisés dans le cadre du programme RSNR-ICE (2014-2023), qui ont permis de mieux comprendre la phénoménologie générale et de valider le principe général de MC3D, basé sur un principe d'ébullition directe autour de la surface des fragments de corium via un mécanisme d'ébullition en film. Or, il apparaît que les processus de fragmentation semblent, dans certaines conditions, se réaliser sans une dispersion significative des fragments dans l'eau, ce qui est contraire à ce que présuppose le modèle MC3D actuel. L'objectif de la thèse est de proposer une modélisation améliorée de l'explosion pour MC3D, combinant le principe actuel d'ébullition directe et d'interaction combustible-refroidissement localisée dans un petit volume autour des gouttes de corium et des fragments. Après une bibliographie extensive du phénomène d'explosion de vapeur, une analyse détaillée du comportement du modèle MC3D actuel est effectuée, en utilisant un cas-test simple et idéal. Malgré la simplicité de l'ensemble de données, l'analyse peut être directement appliquée aux expériences à géométrie unidimensionnelle telles que KROTOS. Le rôle crucial du vide initial et du vide créé est mis en évidence ; il suggère également les premiers contours d'un nouveau modèle. Le logiciel Basilisk a ensuite été utilisé pour effectuer des simulations DNS afin d'obtenir des détails sur les transferts thermiques de fragmentation et d'association. Une analyse complète des régimes de fragmentation, des statistiques incluant le diamètre moyen de Sauter et la fonction de densité de probabilité de la masse et de la surface des fragments, du nombre de Nusselt transitoire et du coefficient de traînée a été menée. Dans le même temps, les résultats du même cas d'essai utilisant MC3D sont comparés à ceux de Basilisk, ce qui met en évidence la nécessité de modifier le modèle MC3D. Enfin, les grandes lignes d'un nouveau modèle proposé sont présentées et discutées. Celles qui ont pu être validées directement à partir des résultats du DNS ont été implémentées dans la version actuelle de MC3D. Il s'agit en particulier de l'introduction d'une Micro-Interaction de Non-Equilibre (NEMI), Les autres propositions concernant le comportement du vide pourront être implémentées dans la future version (V4) du codeThe steam explosion is one of the most critical and complex phenomena that may occur during severe accident in a Nuclear Power Plant. The MC3D computer code is recognized as reference for the evaluation of this phenomenon. This explosive phenomenon is analogous to a detonation. The explosion is due to the fragmentation of the molten fuel, the passage of the shock wave and the very fast release of the associated energy. However, the precise mechanisms of the process of pressurization are very uncertain and have been the subject of works carried out under the program RSNR-ICE (2014-2023), which led to an increased understanding of general phenomenology and validated the general principle of MC3D, based on a principle of direct boiling around the surface of the corium fragments via a film boiling mechanism. However, it appears that the fragmentation processes seem, under certain conditions, to be achieved without a significant dispersion of the fragments in the water, which is contrary to what presupposes the current MC3D model. The aim of the thesis is to propose an improved modeling of the explosion for MC3D, combining the current principle of direct boiling and fuel-coolant interaction localized in a small volume around the corium drops and fragments. Following an extensive bibliography of the steam explosion phenomenon, a detailed analysis of the behavior of the current MC3D model is performed, using a simple and ideal test-case. Despite the simplicity of the data set, the analysis can be directly applied to experiments with one-dimensional geometry such as KROTOS. The crucial role of initial and created void is highlighted; It also suggests the first outlines of a new model. The Basilisk software was then used to perform DNS simulations to get details of fragmentation and association heat transfers. Comprehensive analysis about fragmentation regimes, statistics including Sauter Mean Diameter and Probability Density Function of fragment mass/area, the transient Nusselt number and drag coefficient were conducted. At the same time, results for the same test-case using MC3D are compared with that of Basilisk, highlighting the need of modification of MC3D model. Finally, the main lines of a proposed new model are presented and discussed. Those that could be directly validated from the DNS results were implemented in the current MC3D version. This concerns in particular the introduction of a Non-Equilibrium Micro-Interaction (NEMI), The other proposals concerning the behavior of the void may be implemented in the future version (V4) of the code
4
Nguyen, Thong T. (Trieu Thong) 1963 Carleton University Dissertation Computer Science. "Creepy: an incremental secondary storage garbage collector." Ottawa.:, 1989.
5
Gómez, Puigpinos René Esteban. "Experimental Assessment of hang up and secondary fragmentation for block caving." Tesis, Universidad de Chile, 2015. http://repositorio.uchile.cl/handle/2250/137096.
Abstract:
Magíster en MineríaEn minería es cada vez más recurrente el desarrollo de operaciones a mayores profundidades. En particular, en la minería subterránea masiva explotada por el método de Block/Panel caving esto genera como consecuencia grandes alturas de columna de material quebrado, desarrollando altos esfuerzos producto de la sobrecarga. Es así que surge la presente investigación, con el propósito de estudiar el impacto de mayores esfuerzos en la extracción y fragmentación del mineral El estudio se centra en dos áreas de interés: la fragmentación secundaria y los eventos de colgadura. Estos tópicos son analizados a través del modelamiento físico, para el cual es utilizado un modelo de flujo confinado ubicado en el Laboratorio de Block Caving de la Universidad de Chile. Este modelo emula la extracción desde una batea a través de un sistema LHD. Los experimentos desarrollados consideran mineral el cual fue previamente preparado para representar dos curvas de fragmentación primaria. Dentro de las variables estudiadas se encuentran: el tamaño de los fragmentos, la carga vertical y la humedad; para las cuales se considera la extracción desde un punto de extracción y desde ambos puntos de la batea. Al evaluar los eventos de colgaduras, los resultados experimentales muestran que una mayor relación entre la abertura de extracción y el tamaño medio de partícula mejora la capacidad de flujo del material, así como la extracción desde ambos puntos de extracción también favorece la aparición de una menor cantidad de eventos, disminuyendo los eventos de colgadura en entre un 20 y 30 porciento al compararlos con la extracción desde un solo punto de la batea. Mientras que al aumentar la carga vertical y la humedad, incrementa el número de colgaduras generadas. También se observa que la altura de las colgaduras incrementa con la carga vertical en mineral seco. A través de los resultados obtenidos, fue posible desarrollar un gráfico para estimar la frecuencia de colgaduras el cual es validado con datos de terreno de diversas operaciones mineras. Por otra parte, es presentado un modelo de conminución con base experimental, el cual permite estimar la fragmentación secundaria a diferentes alturas de columna extraída. A diferencia de otros modelos de predicción de fragmentación secundaria, este modelo considera el esfuerzo vertical asociado a la sobrecarga de material quebrado. Finalmente, el modelo propuesto es comparado con la fragmentación generada en operaciones de block caving mostrando la capacidad del modelo planteado para modelar las curvas de fragmentación. Los resultados obtenidos en cuanto a colgaduras y predicción de la fragmentación secundaria, tienen aplicación en el diseño y planificación en minería de caving, a través del gráfico de estimación de colgaduras y el modelo de conminución presentados.
6
Henriquet, Pierre. "Étude de l’émission de particules chargées secondaires dans l’optique d’un monitorage faisceau et de la dosimétrie en ligne en hadronthérapie." Thesis, Lyon 1, 2011. http://www.theses.fr/2011LYO10111/document.
Abstract:
Ce travail est consacré à l'étude de faisabilité d'une imagerie par reconstruction de vertex (IRV) pour le contrôle qualité en temps réel de la thérapie par faisceau d'ions carbone. La détection de vertex d'interactions nucléaires repose sur la détection de particules secondaires : grâce à un dispositif de détection spatiale des fragments chargés (tracker), on peut reconstruire les trajectoires des particules émergeant du patient et les extrapoler jusqu'à leur point d'origine (le vertex)... Dans le cadre de notre étude, la position du vertex est déterminée de deux manières différentes : soit en calculant l'intersection de la trajectoire d'un fragment émergent avec celle de l'ion incident (connue grâce à l'utilisation d'un hodoscope de faisceau placé en amont du patient), soit grâce à l'intersection de la trajectoire de deux fragments émergents détectés en coïncidence. Notre étude de faisabilité de la technique repose sur l'outil de simulation GEANT4. La première partie de l'étude a consisté à valider cet outil grâce à plusieurs expériences réalisées au GANIL (Caen) et au GSI (Darmstadt) avec des ions carbone de différentes énergies dans des cibles d'eau ou de PMMA Par la suite, la comparaison des deux modes de détection des particules secondaires a montré que la technique utilisant l'hodoscope est la plus performante. Enfin, après l'optimisation des principaux paramètres de cette technique, une simulation réaliste montre qu'il est possible de mesurer le parcours des ions avec une précision millimétrique à l'échelle d'une tranche en énergie voire à l'échelle d'un voxel uniqueThis work is devoted to the feasibility study of interaction vertex imaging (IVI) for real-time quality assurance in hadrontherapy treatments with carbon ion beams. Nuclear interaction vertex detection is based on secondary particle detection: a device allows us to spatially detect charged particles (tracker), thus we can reconstruct the trajectories of particles emerging from the patient and then extrapolate their emission point (vertex). In our study, the vertex position is determined by two ways: either by calculating the intersection of the trajectory of an emerging fragment with the trajectory of the incident ion (measured by means of a beam hodoscope upstream of the patient), or with the intersection of two emerging particles trajectories detected in coincidence. Our feasibility study of this technique relies on the GEANT4 simulation tool. The first part of the study aimed to validate this tool with experiments performed at GANIL (Caen) and GSI (Darmstadt) using carbon ion beams at various energies and in various targets (water or PMMA). Secondly, the comparison of two different technics for secondary particles detection showed that the technique using the hodoscope is the most efficient. Finally, after the parameters optimization of this technique, a realistic simulation shows that it is possible to measure ion paths within millimeter precision during each energy slices. A control of each beam spot may also be possible
7
Dorador, Leonardo. "Experimental investigation of the effect of broken ore properties on secondary fragmentation during block caving." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/59392.
Abstract:
Block cave mining is experiencing a global growth in importance as new large, lower grade and deeper ore bodies favouring underground mass mining methods are developed. With block caving, the rock mass fragmentation process is decisive in the design and success of the operation. The last stage of this fragmentation process known as secondary fragmentation, plays a major role in the design and success of a caving operation. Despite this, it is the least understood fragmentation stage due in part to the complex mechanisms and the numerous variables involved in this phenomenon. The broken ore density (BOD) and the inter-block friction angle (ϕ') are comprehensively investigated here. A conceptual framework describing the BOD distribution and a procedure to evaluate this parameter under both an isolated movement zone and interactive flow are proposed, and an approach to evaluate ϕ' under different broken ore properties and draw column conditions is developed to be applied to early stage feasibility studies and design. A comprehensive laboratory testing program was carried out using concrete cuboids, controlling their size, shape and compressive strength. These are used as a proxy for broken ore fragments. These results were used to develop empirical design charts for assessing secondary fragmentation and hang-ups potential. Several factors influencing the secondary fragmentation for feasibility and advanced engineering assessments have been investigated including: air gap thickness, BOD, segregation of large blocks due to draw column surface topology, broken ore strength heterogeneity, block strength damage and crushing under high confining stresses, water within draw columns, and cushioning by fines. This new knowledge will contribute to more accurate secondary fragmentation predictions at the drawpoints. Finally, a new empirical approach to predict secondary fragmentation and drawpoint block size distribution (BSD) directed at early-stage conceptual and feasibility engineering design studies is developed. This methodology, built with relevant data from related fields and supplemented by generated data, was tested against field data from the El Teniente mine, Chile, confirming satisfactory predictions for stronger rocks and mixtures of strong and weak broken ore materials. The results were not as reliable for predicting drawpoint BSD for weak rocks.Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
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Svensson, Ofir. "Does small-scale land use affect the understory birds negative in the Peruvian National Reserve Allpahuayo Mishana?" Thesis, Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-25017.
Abstract:
Human activities that lead to fragmentation and habitat loss are big problems in the world. Due to global climate change the negative effects of fragmented habitats can be catastrophic for many organisms. In the Amazon rainforest, that is most sensitive to human impact, stands a big risk to lose its species diversity. Fragmentation and climate change together seems to escalate the death rate of rainforest plants and that will change the whole ecosystem. Birds and insects are depending on the trees and the trees faces big challenges now. Many of the rainforest organisms have been noticed to emigrate further up to northern altitudes due to the warmer climate and maybe also because of deforestation. Many of the lowland forest birds are predicted to distribute from their origin habitats. The national reserve Allpahuayo Mishana in the Peruvian Amazon is known for its diversity of birds. It is a big challenge for the reserve to maintain the origin forest composition from climate change, which will lead to losses of species. The reserve allows the local community to utilize the land for small-scale uses inside the protected zone. Many of the birds are sensitive for external disturbance. Most human activities are resulting in that the forest becomes less dense, which can lead to that the territory for the birds decreases. This makes it important for the reserve to improve the human land use not to restrict the birds' habitat inside the reserve. This project will investigate if the small-scale land uses affects the understory birds’ diversity and habitat negative. The purpose is to see if the fragmented forests in the reserve, closest to the utilized land, can functioning as a secondary forest for the understory birds, or are the understory birds limited by the small-scale land use, in the national reserve Allpahuayo Mishana? Four sites with various human activities were chosen to investigate if the sites contain any understory birds. The result showed that the most disturbed sites had poor bird diversity compare to the sites with no human disturbance.
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Noda, Margareth. "Fragmentação do mercado secundário: desafios para a regulação do Brasil." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/2/2132/tde-17122015-105852/.
Abstract:
O mercado de capitais, e especialmente o mercado secundário, está entre os setores da economia que reagem mais prontamente às inovações tecnológicas. Nos últimos anos, o desenvolvimento tecnológico e das telecomunicações alterou dramaticamente a configuração do mercado secundário: os pregões viva-voz desapareceram, dando lugar aos sistemas eletrônicos de negociação que executam negócios a velocidades imperceptíveis ao ser humano. Concomitantemente, alterações regulatórias visando ao aumento da concorrência nos mercados secundários proporcionaram a criação de ambientes de negociação com e sem transparência, gerando a fragmentação da liquidez. No Brasil, embora o mercado seja altamente eletronificado e o processo de alteração regulatória também tenha ocorrido, não se verificou o aumento da concorrência no mercado secundário de ações. A partir de uma análise comparativa com mercados fragmentados, este trabalho propõe algumas reformas na regulação brasileira com vistas a melhoraria da qualidade do mercado por meio da introdução de concorrência.Capital markets, and especially the secondary market, are among the sectors that react more quickly to technological innovations. In recent years, technological and telecommunication developments dramatically changed the structure of the secondary market: the open outcry sessions disappeared, giving way to electronic trading systems with execution speeds imperceptible to humans. At the same time, regulatory changes aimed at increasing competition in the secondary markets led to the creation of lit and dark trading venues, generating the fragmentation of liquidity. In Brazil, although the market is highly electronic and the regulatory change process has also occurred, there was no increased competition in the secondary stock market. From a comparative analysis with fragmented markets, this paper proposes some reforms in the Brazilian regulation in order to improve the quality of the market through the introduction of competition.
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Yakambram, P. "Synthetic studies toward peloruside a, clavosolides and temperature dependent isomerisation versus net fragmentation of secondary allylic alcohols with grubbs’ catalyst." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2006. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2502.
Books on the topic "Fragmentation secondaire":
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Pospeev, Konstantin, Vitaliy Chernyh, Andrey Mayorov, and Il'mirovich Ruslan. Fire training. ru: INFRA-M Academic Publishing LLC., 2022. http://dx.doi.org/10.12737/1845930.
Abstract:
The textbook contains material on the legal foundations of the use of firearms, the basics of shooting, safety measures when handling weapons and ammunition, the material part of firearms and hand fragmentation grenades, the organization and conduct of shooting in the units of internal affairs bodies.
The content of the textbook reflects the peculiarities of the formation of students' professional competencies in the academic discipline "Fire training" that meet the requirements of the Federal State Educational Standard of secondary vocational education in the specialty 40.02.02 "Law Enforcement".
For teachers of secondary vocational and higher education, students (cadets) studying in the specialty 40.02.02 "Law enforcement", as well as for employees of internal affairs bodies.
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Yust, Jason. Formal Structure. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190696481.003.0004.
Abstract:
William Caplin’s concept of formal functions points the way to a more flexible theory of form based on processes and structuring principles rather than fixed schemata. This chapter further generalizes the theory of formal functions to a set of form-structural criteria based on repetition, fragmentation, caesura, and contrast. The chapter also constructs such a theory of form without necessary reference to tonal criteria, thus serving the larger project of understanding form as an independent musical dimension, capable of disjunction with, or non-trivial coordination with, tonal structure. A definition of secondary theme as a specialization of subordinate theme function is also proposed.
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Reading, Paul J. Neurological diseases and their effects on the sleep–wake cycle. Edited by Sudhansu Chokroverty, Luigi Ferini-Strambi, and Christopher Kennard. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780199682003.003.0035.
Abstract:
This chapter addresses current neurobiological knowledge of how wake- and sleep-promoting systems interact to produce the daily circadian rhythm of wake and sleep and how this may be adversely affected by a variety of neurological diseases. The crucial importance of sleep quality for optimal brain function is stressed and the potential hazards of prolonged wakefulness highlighted. Insomnia relating to either sleep onset or maintenance is common and increases with normal aging. Many neurodegenerative diseases such as Alzheimer disease appear to enhance the effects of aging on the sleep–wake cycle, with increased fragmentation and reduced deep sleep. Focal pathology in the thalamus or sometimes the hypothalamus may produce striking insomnia, as may several autoimmune encephalitides. Hypersomnia is most often secondary to poor-quality nocturnal sleep, but may also relate to discrete hypothalamic pathology or traumatic head injury. The effects of epilepsy and its treatment on sleep can be significant and are discussed.
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von Möllendorff, Malve. Positioning Diversity in Kenyan Schools: Teaching in the Face of Inequality and Discrimination. African Minds, 2022. http://dx.doi.org/10.47622/9781928502333.
Abstract:
Education is considered key for societies to achieve greater social cohesion and equality. Yet, schools, as the main providers of formal education, have increasingly come into question concerning their role in manifesting and perpetuating social categorisations, inequalities and discrimination instead of decreasing existing fragmentations and challenging power relations and hierarchies. As a diverse society, Kenya is faced with power struggles and rivalries between different groups – for instance, along ethnic lines, often constructed deep in colonial history. This affects teaching and learning in school and the result is that Kenya is faced with vast disparities in terms of educational access and success – rendering some social groups marginalised and others favoured. Positioning Diversity at Kenyan Schools explores the ways in which teachers in Kenyan primary and secondary schools experience and deal with social categorisations and diversity in terms of ethnicity, gender, wealth, culture, religion, etc. in their professional practice and in the current education system. Using critical pedagogy and diversity theory as a lens for positioning diversity in Kenyan schools, the questions that this book sets out to answer are: In what ways do the teachers’ and schools’ practices lead to transformation in terms of more social equality and less discrimination? In what ways do the practices manifest existing group categorisations, hierarchies and discrimination? How can schools and teaching practices in postcolonial Kenya become more inclusive and foster social cohesion and equality?
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Martin, S. Rebecca, and Stephanie M. Langin-Hooper, eds. The Tiny and the Fragmented. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190614812.001.0001.
Abstract:
Miniature and fragmentary objects are both remarkably fascinating and easily dismissed. Tiny scale entices users with visions of Lilliputian worlds. The ambiguity of fragments intrigues us, offering vivid reminders of the transitory nature of reality. Yet, the standard scholarly approach to such objects has been to see them as secondary, incomplete things, designed primarily to refer to a complete and often life-sized whole. This volume offers a series of fresh perspectives on the familiar concepts of the tiny and the fragmented, in chapters ranging in focus from Neolithic Europe to Pre-Columbian Honduras to the Classical Mediterranean and Ancient Near East. Diverse in scope, the volume is united in considering the little and broken things of the past as objects in their own right. When a life-sized or whole thing is made in a scaled-down or partial form, deliberately broken as part of its use, or considered successful by ancient users only if it shows some signs of wear, it challenges our expectations of representation and wholeness. Overall, this volume demands a reconsideration of the social and contextual nature of miniaturization, fragmentation, and incompleteness. These were more than just ancient strategies for saving space, time, and resources. Rather, they offered new possibilities of representation, use, and engagement—possibilities unavailable with things that were life size or more conventionally “complete.” It was because of, rather than in spite of, their small or partial state that these objects were valued parts of the personal and social worlds they inhabited.
Book chapters on the topic "Fragmentation secondaire":
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Mehra, Salil K., and Marketa Trimble. "Secondary Liability of Internet Service Providers in the United States: General Principles and Fragmentation." In Secondary Liability of Internet Service Providers, 93–108. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-55030-5_3.
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Henrekson, Magnus, and Johan Wennström. "The Deinstitutionalization and Fragmentation of the Swedish School System." In Dumbing Down, 117–39. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-93429-3_7.
Abstract:
AbstractThe chapter shows how the educational trend of “post-truth” schooling continued in Sweden into the twenty-first century. It offers a close reading of the national curriculum that was in force at the time of writing (in 2021). The chapter also discusses how the Swedish school system in just a few years went from being very strictly regulated to being the polar opposite. These changes included a radical marketization of primary and secondary schooling that is unparalleled in any wealthy Western country. The chapter analyzes the school choice market in Sweden and describes how it interacts with postmodern social constructivist ideas, to the detriment of the teaching of knowledge in a classical sense.
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Bedrosian, Bryan. "Avian Predators in Rangelands." In Rangeland Wildlife Ecology and Conservation, 471–504. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-34037-6_14.
Abstract:
AbstractManagement of avian predators in western rangelands is uniquely challenging due to differences in managing for/against particular species, management of sensitive prey species, long-standing human/wildlife conflicts, and the unique legal protections within this ecological group. In general, many avian predator species considered rangeland specialists have been declining due to habitat loss, fragmentation, human sensitivity, and direct persecution. Conversely, avian predators that are more human-tolerant and/or are subsidized by human activities are significantly increasing across rangelands. The complicated nature of inter- and intra-species guilds, coupled with human dynamics has created a challenging scenario for both management for avian predators, as well as their prey. Human-mediated population control, both legal and illegal, continues for avian predators to reduce livestock conflict, aid sensitive prey populations, and/or because of general predator persecution. Conversion of rangeland to development for energy, cultivation, and urbanization remains the largest impediment to maintaining viable, historical assemblages of avian predators. Large-scale habitat protections, reduction of invasive plants, and reducing wildfire will continue to enhance at-risk populations of predators and their prey. Further, mediating human-induced mortality risks will also aid at-risk predator populations, such as reducing direct killing (poisoning and shooting), secondary poisoning from varmint control and lead ammunition use, electrocutions, and vehicle strikes, while reducing anthropogenic subsidies can help curtail population expansion of corvids. Additional understanding of long-term, successful predator control efforts for corvids and mitigation options for declining raptors is needed to help balance the avian predator–prey dynamic in western rangelands.
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"Differentiation without fragmentation." In Differentiation and the Secondary Curriculum, 55–70. Routledge, 2005. http://dx.doi.org/10.4324/9780203989609-13.
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Carlos, Lopez Jimeno, Lopez Jimeno Emilio, Javier Ayala Carcedo Francisco, and Ramiro Yvonne Visser de. "Secondary fragmentation and special blastings." In Drilling and Blasting of Rocks, 299–304. Routledge, 2017. http://dx.doi.org/10.1201/9781315141435-29.
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Horning, Ned, Julie A. Robinson, Eleanor J. Sterling, Woody Turner, and Sacha Spector. "Landscape fragmentation." In Remote Sensing for Ecology and Conservation. Oxford University Press, 2010. http://dx.doi.org/10.1093/oso/9780199219940.003.0018.
Abstract:
The country of Vietnam has long been recognized as an important region for biodiversity (Sterling et al. 2006). High-profile discoveries in the 1990s of many species new to science including large ones such as the Saola (Pseudoryx nghetinhensis), an 85 kg basal member of the cattle subfamily Bovinae and the first new genus of large land-dwelling mammal described since the okapi (Okapia johnstoni) in 1901, have focused the attention of national and international conservation organizations on Vietnam and surrounding countries in mainland Southeast Asia (Hurley et al. in prep.). Conservation action for these endemic, endangered species relies on a clear understanding of trends in habitat conversion. To track deforestation rates through time in Vietnam, Meyfroidt and Lambin (2008) combined remotely sensed data with landscape metrics such as number of patches, mean patch size, mean proximity index, and total core area index. They tested their analyses across a variety of land cover studies including those using Advanced Very High Resolution Radiometer (AVHRR), Landsat, SPOT, and MODIS data sources. They found that forest cover decreased nationally from the 1980s to the 1990s and then showed an increase between 1990 and 2000, due to plantation forests as well as natural forest regeneration. However, the effects of this forest transition on fragmentation metrics noted above differed across the country. For instance, in some places, such as central Vietnam where forest cover is relatively large and well connected, reforestation led to a decrease in forest fragmentation and secondary forests recovered rapidly. However in others, such as areas in the north where forest fragmentation dates back centuries and forests have therefore long been isolated, reforestation did not seem to have an impact on continued fragmentation and habitat loss. In this chapter we detail the importance of fragmentation and landscape metrics to ecology and conservation, outlining when and where remotely sensed data can help in these analyses. We then discuss a subset of fragmentation metrics and point to some challenges in processing fragmentation data. We provide examples of composition and connectivity metrics illuminated with examples from the remote sensing literature.
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Kajtár, Gábor. "Fragmentation of Attribution in International Law." In Secondary Rules of Primary Importance in International Law, 283—C15.N*. Oxford University PressOxford, 2022. http://dx.doi.org/10.1093/oso/9780192869012.003.0015.
Abstract:
Abstract This chapter examines the practice of international courts and tribunals and contends that adjudicators, consciously or unconsciously, use the notion of attribution in a narrow and in a broad sense, without however properly distinguishing between nuanced attribution standards. Attribution tests in the narrow sense are drawn from the International Law Commission (ILC) Articles on Responsibility of States for Internationally Wrongful Acts (ARSIWA) and are applied in the context of establishing the international responsibility of states. Whereas broad sense attribution concepts serve a variety of other legal purposes. This phenomenon will be termed as the fragmentation of attribution. The chapter will map various attribution concepts used in the field of jus ad bellum, jus in bello, and international investment law. It concludes by raising awareness about the doctrinal inconsistencies that arise from the judicial use of different attribution tests in an interchangeable way and about a corresponding need for doctrinal scrutiny and methodological consistency in dealing with secondary rules of international law.
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Elmo, D., S. Rogers, L. Dorador, and E. Eberhardt. "An FEM-DEM numerical approach to simulate secondary fragmentation." In Computer Methods and Recent Advances in Geomechanics, 1623–28. CRC Press, 2014. http://dx.doi.org/10.1201/b17435-286.
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Lubman, David M., and Liang Li. "Resonant Two-Photon Ionization Spectroscopy of Biological Molecules in Supersonic Jets Volatilized by Pulsed Laser Desorption." In Lasers and Mass Spectrometry, 353–82. Oxford University PressNew York, NY, 1990. http://dx.doi.org/10.1093/oso/9780195059298.003.0016.
Abstract:
Abstract Mass spectrometry (MS) remains one of the most powerful means of chemical analysis based on exact mass identification of molecular species. One of the most active areas within this field has been the development of new and more versatile ionization sources. For identification purposes soft ionization methods are often desirable in which only the molecular or parent ion is obtained for mass analysis. However, an additional parameter for identification and structural analysis can be based upon the ability to produce fragment ions that are characteristic of the structure of that species. Numerous methods have been devised to produce soft ionization including chemical ionization (CI), fast atom bombardment (FAB), plasma desorption (PD), field ionization (Fl), and secondary ion mass spectrometry (SIMS). Other methods such as electron bombardment or collision-induced dissociation are capable of generating extensive fragmentation.
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"Secondary Imagination, Contamination, and Androgyny: Rethinking Coleridgean Fragmentation from “Kubla Khan” and Christabel to Magnum Opus." In Rethinking the Romantic Era. Bloomsbury Academic, 2021. http://dx.doi.org/10.5040/9781350167414.ch-003.
Conference papers on the topic "Fragmentation secondaire":
1
Rimbert, Nicolas, M. Hadj-Achour, and M. Gradeck. "Liquid-Liquid Secondary Fragmentation with Solidification." In ILASS2017 - 28th European Conference on Liquid Atomization and Spray Systems. Valencia: Universitat Politècnica València, 2017. http://dx.doi.org/10.4995/ilass2017.2017.5034.
Abstract:
In the event of a hypothetical core disruptive accident in nuclear power plants, the molten core may flow out thereactor vessel and interact with the cold water. The evolution of the accident is strongly affected by the fragmentation of the jet of molten metallic fuel due to its interaction with the water (i.e. this situation is known as fuel coolant interaction, FCI). In order to evaluate and predict the various consequences of a FCI, many researches are conducted with either corium or high melting temperature molten metal, where premixing stage evolves with an important production of steam. This steam production that is unavoidable because the high temperature of corium leads to difficulties for using optical diagnostics. Hence, in our case, we use a eutectic alloy (Field’s metal) with a low melting point (62°C) in order to be able to visualize correctly the droplet fragmentation processes.The present work focuses on the fragmentation of a single Field’s metal liquid droplet with mass equals to 0.27g (±0.01g). The liquid droplet interacts with a water pool whose temperature range between 20°C to 60°C. According to its Weber number, it fragments in different ways. For each experiment, a single droplet has been visualized using a high-speed camera (at 8000 fps). All measurements (drop size, velocity, impact parameter and geometrical properties of the drops after the penetration) into the pool are evaluated using an open source image processing. Solidified fragments can then be sieved and the size PDF determined. Focus of the present work is put on the evolution of the Sauter Mean Diameter with increasing Weber number and varying bath pool temperature. It is shown that using a simple crust model during solidification and defining an effective Weber number which include the crust elasticity all the curves collapse on the same master curve for all the water bathtemperature considered.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.5034
2
Qaddah, Baraa, Pierre Chapelle, Jean Pierre Bellot, Julien Jourdan, Nicolas Rimbert, Agathe Deborde, and Raphael Hammes. "Primary And Secondary Breakup Of Molten Ti64 In An EIGA Atomizer For Metal Powder Production." In Euro Powder Metallurgy 2023 Congress & Exhibition. EPMA, 2023. http://dx.doi.org/10.59499/ep235749638.
Abstract:
Gas atomization is the predominant method of powder production for metal additive manufacturing. The EIGA atomizer (Electrode Induction melting Gas Atomization) is a free-fall process used to produce spherical powders, particularly for refractory and high-purity metals such as the titanium alloy Ti-6Al-4V (Ti64). In this process, a swirling supersonic gas jet hits a molten metal stream atomizing it into small droplets through various fragmentation mechanisms. To identify the different fragmentation mechanisms of molten Ti64 within the process, a visualization of the metal atomization by a high-speed video camera is performed in an EIGA tower. The role of the atomization gas pressure on the fragmentation mechanisms and on the final particle size distribution is determined. The mechanisms observed are fiber breakup, bag breakup and Rayleigh breakup for primary fragmentation and bag breakup and shear breakup for secondary fragmentation. Key words: Free-fall atomizer; swirling supersonic gas flow; metal powder; primary fragmentation; secondary fragmentation; high-speed camera.
3
Svetlichnyi, Aleksandr, Roman Nepeivoda, Nikita Kozyrev, and Igor A. Pshenichnov. "Secondary nuclei from O-16 fragmentation at the LHC." In The European Physical Society Conference on High Energy Physics. Trieste, Italy: Sissa Medialab, 2022. http://dx.doi.org/10.22323/1.398.0310.
4
Pierce, Matthew, Dion Weatherley, and Toni Kojovic. "A hybrid methodology for secondary fragmentation prediction in cave mines." In Second International Symposium on Block and Sublevel Caving. Australian Centre for Geomechanics, Perth, 2010. http://dx.doi.org/10.36487/acg_rep/1002_39_weatherley-pierce.
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STRIZHAK, P. A., and D. V. ANTONOV. "PUFFING AND MICROEXPLOSION IN SECONDARY DROPLETS." In 13th International Colloquium on Pulsed and Continuous Detonations. TORUS PRESS, 2022. http://dx.doi.org/10.30826/icpcd13a13.
Abstract:
Secondary atomization of droplets (in the partial or full fragmentation regime) in multiphase and multicomponent fuel §ows is a promising technology that can minimize fuel consumption, improve the combustion dynamics, reduce anthropogenic emissions, stabilize fuel injection in a combustion chamber, and reduce the equipment wear [1, 2]. The most promising secondary atomization schemes involve droplet droplet collisions in intersecting fuel jets [3], droplet collisions with a solid surface in the form of walls, rings, meshes, and ledges [4], microexplosion, and pu©ng [5]. As a result of a microexplosion, the droplets of multiphase and multicomponent fuels break up to form an array of liquid fragments with a size of 1 100 μm [5]. The aim of this work is experimental research of pu©ng and microexplosion in secondary droplets. The number and radii of secondary fragments (child droplets) were analyzed by Shadow Photography (SP). Three approaches have been used to improve the accuracy of the experimental ¦ndings and to estimate their repeatability in a series of experiments. The measurements did not deviate by more than 5%. From the experiments conducted, the present authors managed to ¦nd the cause of signi¦- cant di¨erences in the characteristics of child droplets being formed in the course of microexplosion and pu©ng of two-liquid droplets for di¨erent formation regimes and identical heating conditions. After the research ¦ndings have been generalized, it became possible to determine the ranges of variation for the main parameters at which the maximum amount of child droplets with the required component composition could be obtained. In particular, the authorshave singled out the maps with multiple input parameters that can be used in the technologies of secondary fragmentation for the intensi¦cation of fuel mixing and combustion, puri¦cation of liquids, intensi¦cation of phase transitions, and heat exchange in power generation units.
6
Gonzalez, E. Maderuelo, J. Santiago Garcia, S. Wang, E. C. Abad Izquierdo, D. de Frutos, E. Llop Herrera, H. D. T. Alberto, and J. L. Calleja Panero. "Colonic obstruction secondary to sigmoid fecaloma treated with Coke injection and endoscopic fragmentation." In ESGE Days 2023. Georg Thieme Verlag KG, 2023. http://dx.doi.org/10.1055/s-0043-1765830.
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Collé, Anthony, Jérôme Limido, Christian Puillet, and Thomas Unfer. "Innovative Fragmentation Modeling for Hypervelocity Impacts of Debris." In 2022 16th Hypervelocity Impact Symposium. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/hvis2022-7.
Abstract:
Abstract The increase in the number of debris in orbit and the increase in the number of nano satellites in orbit leads to the need to better understand the debris likely to be generated by these nano satellites: either by explosion from an internal energy source, or by explosion following an impact by a large external debris. The aim of this research is to explore innovative fragmentation modelling solutions implemented in Impetus Afea Solver in the context of hypervelocity impacts of debris. Thus, through this work, a complete and detailed study of complex structures under hypervelocity impacts is successfully performed with the γ-SPH-ALE Solver. Thanks to its robustness and accuracy, Impetus can properly reproduce the experimental results. Particularly, the influence of the impact velocity on the multi-impact and perforation of a secondary plate is correctly handled as well as the behavior of a complete nanosatellite structure. The combination with an efficient fragment detection algorithm makes it possible to perform an accurate fragment analysis on the fly, and to exploit the data with in-house codes. In addition, the benefit from GPU acceleration significantly reduces the computation times with respect to classical SPH approaches allowing to meet industrial needs and to consider real orbital structures.
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Santos, João Vitor Ribeiro dos, Mariana Spitz, and Ana Carolina Andorinho. "Stroke secondary to thrombotic microangiopathy." In XIII Congresso Paulista de Neurologia. Zeppelini Editorial e Comunicação, 2021. http://dx.doi.org/10.5327/1516-3180.300.
Abstract:
Introduction: Thrombotic thrombocytopenic purpura (TTP) is a hematological disease resulting from the ADAMTS 13 plasmatic protein deficit. It can be congenital or sporadic, and is usually autoimmune. Pathological platelet adhesion occurs, leading to microthrombi in capillary and arterial circulation, microangiopathic anemia and ischemia. The clinical picture includes thrombocytopenia, renal dysfunction, fluctuating neurological symptoms, microangiopathic hemolytic anemia, and fever. Methods: Case report of a 51-year-old male hypertensive patient, diagnosed with idiopathic thrombocytopenic purpura (ITP) 10 years ago and submitted to splenectomy 5 years ago, who developed acute cholecystitis. He underwent urgent colecistectomy, and on the fourth postoperative day presented sudden space and time disorientation, transcortical motor aphasia and right faciobrachial paresis, with ipsilateral Babinski and Hoffman signs. Results: Brain CT showed left frontoparietal hypodensity. During hospitalization, there was worsening of renal function, increased LDH, and thrombocytopenia. Hematoscopy identified signs of intravascular hemolysis (erythrocyte fragmentation, reticulocytosis, helmet erythrocytes). Direct Coombs was negative. There was no history of heparin use. TTP was diagnosed, and fresh frozen plasma and prednisone 1mg/kg were prescribed. There was resolution of thrombotic microangiopathy, with subsequent increase of platelet levels, decreased LDH and improved hematoscopy. Conclusions: This case illustrates a rare cause of stroke and an unusual association of two hematological conditions: ITP and TTP. The treatment of TTP consists of replacement of deficient ADAMTS13 protein through plasmapheresis or fresh frozen plasma. The use of immunosuppressants is also associated, initially with glucocorticoids, followed by rituximab or splenectomy in order to prevent recurrences.
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Dostál, Ivo, Petr Anděl, Marek Havlíček, and František Petrovič. "Landscape Fragmentation Around Us – Integrating the Issue into Educational Processes at Primary and Secondary Schools." In 27th edition of the Central European Conference with subtitle (Teaching) of regional geography. Brno: Masaryk University Press, 2020. http://dx.doi.org/10.5817/cz.muni.p210-9694-2020-1.
Abstract:
The steadily increasing landscape fragmentation and the reduction of permeability for wildlife are among the most negative impacts of human activity on the environment. In terms of education, theseproblems appear to be rather demanding, withthe difficulty corresponding tosecondary school standards. Considering the multiple interdisciplinary connections, the entire process cannot be sufficiently understood without a relevant amount of preliminary knowledge. Such a corpus of information is acquired especially through biology/ecology, geographyand history classes, but links to other subjects can be found too. The paper presents didactic methods facilitating the actual presentation of the theme to pupils/students; in this context, the authors discuss the possibilities of integrating the given problems into applicable schoolsubjects andoutline the risks arising from the proposed modification and/ or expansion of the teaching procedures. Also the links to data and supporting methodological materials are included that will allow the teacher to obtain enough information on the topicsto comprehend all the aspects and complexities of the innovated classes. In the corresponding sections, the papercharacterizes individual topics to be combined with selected teaching methods, especially as regards worksheets, project-oriented education, anda case study relating to afield trip targeting one of the areas of high importance for wildlife migration in the Czech Republic.
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Dorador Ortiz, Leonardo, Erik Eberhardt, and Davide Elmo. "Influence of rock mass veining and non-persistent joints on secondary fragmentation during block caving." In Fourth International Symposium on Block and Sublevel Caving. Australian Centre for Geomechanics, Perth, 2018. http://dx.doi.org/10.36487/acg_rep/1815_18_dorador.
Reports on the topic "Fragmentation secondaire":
1
Snyder, Victor A., Dani Or, Amos Hadas, and S. Assouline. Characterization of Post-Tillage Soil Fragmentation and Rejoining Affecting Soil Pore Space Evolution and Transport Properties. United States Department of Agriculture, April 2002. http://dx.doi.org/10.32747/2002.7580670.bard.
Abstract:
Tillage modifies soil structure, altering conditions for plant growth and transport processes through the soil. However, the resulting loose structure is unstable and susceptible to collapse due to aggregate fragmentation during wetting and drying cycles, and coalescense of moist aggregates by internal capillary forces and external compactive stresses. Presently, limited understanding of these complex processes often leads to consideration of the soil plow layer as a static porous medium. With the purpose of filling some of this knowledge gap, the objectives of this Project were to: 1) Identify and quantify the major factors causing breakdown of primary soil fragments produced by tillage into smaller secondary fragments; 2) Identify and quantify the. physical processes involved in the coalescence of primary and secondary fragments and surfaces of weakness; 3) Measure temporal changes in pore-size distributions and hydraulic properties of reconstructed aggregate beds as a function of specified initial conditions and wetting/drying events; and 4) Construct a process-based model of post-tillage changes in soil structural and hydraulic properties of the plow layer and validate it against field experiments. A dynamic theory of capillary-driven plastic deformation of adjoining aggregates was developed, where instantaneous rate of change in geometry of aggregates and inter-aggregate pores was related to current geometry of the solid-gas-liquid system and measured soil rheological functions. The theory and supporting data showed that consolidation of aggregate beds is largely an event-driven process, restricted to a fairly narrow range of soil water contents where capillary suction is great enough to generate coalescence but where soil mechanical strength is still low enough to allow plastic deforn1ation of aggregates. The theory was also used to explain effects of transient external loading on compaction of aggregate beds. A stochastic forInalism was developed for modeling soil pore space evolution, based on the Fokker Planck equation (FPE). Analytical solutions for the FPE were developed, with parameters which can be measured empirically or related to the mechanistic aggregate deformation model. Pre-existing results from field experiments were used to illustrate how the FPE formalism can be applied to field data. Fragmentation of soil clods after tillage was observed to be an event-driven (as opposed to continuous) process that occurred only during wetting, and only as clods approached the saturation point. The major mechanism of fragmentation of large aggregates seemed to be differential soil swelling behind the wetting front. Aggregate "explosion" due to air entrapment seemed limited to small aggregates wetted simultaneously over their entire surface. Breakdown of large aggregates from 11 clay soils during successive wetting and drying cycles produced fragment size distributions which differed primarily by a scale factor l (essentially equivalent to the Van Bavel mean weight diameter), so that evolution of fragment size distributions could be modeled in terms of changes in l. For a given number of wetting and drying cycles, l decreased systematically with increasing plasticity index. When air-dry soil clods were slightly weakened by a single wetting event, and then allowed to "age" for six weeks at constant high water content, drop-shatter resistance in aged relative to non-aged clods was found to increase in proportion to plasticity index. This seemed consistent with the rheological model, which predicts faster plastic coalescence around small voids and sharp cracks (with resulting soil strengthening) in soils with low resistance to plastic yield and flow. A new theory of crack growth in "idealized" elastoplastic materials was formulated, with potential application to soil fracture phenomena. The theory was preliminarily (and successfully) tested using carbon steel, a ductile material which closely approximates ideal elastoplastic behavior, and for which the necessary fracture data existed in the literature.