Collision Simulation in plasma Sheath Using the Monte Carlo Technic

In this work we studied the collisions in the sheath and their influence on the energy transferred to the cathode by Monte carlo simulation .The comparison between results obtained by Monte Carlo simulation and those obtained by simulation of Runge Kutta is carried out. We stadied too the influence of the collision on the erosion of the cathode, and we give a technique to calculate the energy of vaporisation.In this work we studied the collisions in the sheath and their influence on the energy transferred to the cathode by Monte carlo simulation .The comparison between results obtained by Monte Carlo simulation and those obtained by simulation of Runge Kutta is carried out. We stadied too the influence of the collision on the erosion of the cathode, and we give a technique to calculate the energy of vaporisation

Ejector applications in refrigeration and heating: An overview of modelling, operation and recent developments

Part of: Thermally driven heat pumps for heating and cooling. – Ed.: Annett Kühn – Berlin: Universitätsverlag der TU Berlin, 2013 ISBN 978-3-7983-2686-6 (print) ISBN 978-3-7983-2596-8 (online) urn:nbn:de:kobv:83-opus4-39458 [http://nbn-resolving.de/urn:nbn:de:kobv:83-opus4-39458]The utilization of ejectors in heat pump systems as compression components, alone or in combination with other equipment, have gained renewed interest as a thermally driven solution for low temperature heat recovery and upgrading and more efficient energy use. This paper summarizes the main findings and trends, in the area of heat driven ejector based machines using low boiling point working fluids. An overall view of such systems is provided by presenting the ejector principles of physics and the latest developments on ejector design, operation and modeling approaches. Aspects related to the analysis of the complex interacting phenomena taking place in these systems for high performance are highlighted. Conventional and improved ejector heat pump cycles of interest employing ejectors alone or boosted combinations are presented and discussed, and their potential applications are indicated. Finally, sample theoretical and experimental results obtained at CanmetENERGY on ejector operation and design are reported

SUBMICRON SIZED SINTERED ODS STEELS PREPARED BY HIGH EFFICIENT ATTRITION MILLING AND SPARK PLASMA SINTERING

ABSTRACTThis paper summarizes recent results for preparation, structural and mechanical investigation of oxide dispersed strengthened steel (ODS). Three commercial steel powders, two austenitic steel and one martensitic powders have been used as starting materials. One of the austenitic powders was used for morphological study during wet milling. The high efficient attrition mills are on the basis of this work assuring grains with nanostructure. The morphological changes during milling steps have been described. It was demonstrated that 4 hours milling in wet atmosphere are enough to realize steel powders with submicron dimensions. An efficient dispersion of nanosized oxides in ODS steels was achieved by employing high efficiency attrition milling. A combined wet and dry milling process of fine ceramic and steel particles has been proposed. Spark Plasma Sintering (SPS) was applied to realize submicron grained steel compacts. Grains with 100 nm mean size have been observed by scanning electron microscopy (SEM) in sintered austenitic ODS. In comparison, the sintered martensitic dry and combined milled ODS microstructure consisted of grain sizes with 100-300 nm in each case.KEYWORDS: ODS Steel, Spark Plasma Sintering (SPS), attrition milling, Nano-oxides, structural and mechanical investigationRESUMECet article résume des résultats récents relatifs à l’élaboration et la caractérisation structurale et mécanique d’un acier renforcé à l'oxyde (nuance appelée souvent ROD/ODS). Trois poudres commerciales d'acier, deux poudres austénitiques et une poudre martensitique ont été utilisées comme matières d’étude. Une des poudres austénitiques a été utilisée pour l'étude morphologique lors du broyage humide. Le broyage à haute efficacité est sur la base de ce travail assurant l’obtention de grains nanostructurés. Les modifications morphologiques au cours des étapes de broyage ont été bien décrites. Il a été démontré que 4 heures de broyage en atmosphère humide sont suffisantes pour réaliser des poudres d'acier de dimensions submicroniques. Une dispersion efficace des nano-oxydes dans les aciers ROD/ODS a été obtenue en utilisant un broyage spécifique. On a proposé un procédé de broyage humide et sec combiné à des particules de céramique et d'acier. La méthode de frittage par étincelle (spark plasma sintering (SPS)) a été appliquée pour élaborer des aciers compacts à grains submicroniques. Des grains ayant une taille moyenne de 100 nm ont été observés par microscopie électronique à balayage (MEB) dans les aciers ROD/ODS austénitiques frittées. En comparaison, la microstructure de l’acier ROD/ODS martensitique frittée a donné des grains de tailles de 100 à 300 nm dans les deux cas de broyage sec et de broyage combiné (humide et sec)

Croissance et développement des plants de deux provenances de chêne-liège produits en pépinière dans des conteneurs de différentes profondeurs

La survie des plants de chêne-liège dans la majorité des sites de reboisement au Maroc reste très faible à cause principalement de l’utilisation des plants dotés d’un système racinaire peu développé qui ne peut pas satisfaire les besoins hydriques des plants dans des sites caractérisés par un déficit hydrique. L’objectif de ce travail consiste à comparer, en pépinière, la croissance et le développement des plants de deux provenances (montagne et plaine) de chêne-liège élevés, pendant cinq mois, dans quatre types de conteneurs de différentes profondeurs (T : témoin de 16 cm, C : court de 30 cm, M : moyen de 60 cm et L : long de 90 cm). La croissance des parties aériennes et racinaires des plants de chêne-liège, après cinq mois de culture, a été significativement influencée à la fois par le type du conteneur et par l’origine géographique des glands. Les conteneurs les plus profonds dotés d’une volumétrie élevée (M et L) ont augmenté significativement les valeurs des paramètres morphologiques incluant la hauteur, la longueur des racines, le diamètre au collet, la masse des racines et des parties aériennes par comparaison aux plants produits dans le conteneur témoin (500 cm3) utilisé généralement pour la production des plants de chêne-liège. Pour tous les types de conteneurs, les plants issus des glands de la subéraie de plaine ont montré une croissance relativement supérieure par rapport à celle des plants de la provenance de montagne. L’utilisation de conteneurs plus profonds pour la production des plants de chêne-liège a contribué significativement à l’amélioration de la croissance des racines et des parties aériennes. La présence d’un système racinaire pivotant long et assez développé permettrait aux plants d’accéder rapidement aux ressources hydriques après plantation tout en leur conférant une tolérance accrue à la sécheresse

An efficient broadcasting routing protocol WAODV in mobile ad hoc networks

Information broadcasting in wireless network is a necessary building block for cooperative operations. However, the broadcasting causes increases the routing overhead. This paper brings together an array of tools of our adaptive protocol for information broadcasting in MANETs. The proposed protocol in this paper named WAODV (WAIT-AODV). This new adaptive routing discovery protocol for MANETs, lets in nodes to pick out a fantastic motion: both to retransmit receiving request route request (RREQ) messages, to discard, or to wait earlier than making any decision, which dynamically confgures the routing discovery feature to decide a gorgeous motion through the usage of neighbors’ knowledge. Simulations have been conducted to show the effectiveness of the using of techniques adaptive protocol for information broadcasting RREQ packet when integrated into ad hoc on-demand distance vector (AODV) routing protocols for MANET (which is based on simple flooding)

De novo assembly of viral quasispecies using overlap graphs

Baaijens JA, Aabidine AZE, Rivals E, Schönhuth A. De novo assembly of viral quasispecies using overlap graphs. Genome Research. 2017;27(5):835-848

The influence of magnetic reversed shear in the improvement of quality of confinement in the plasma of Tokamak: Comparison between TEXTOR & ITER

The reversed magnetic shear is the most important factor in the studies of the plasmas of tokamak. In this paper we focus our research, at first stage, on the control of the improved confinement regimes by studying the influence of reversed shear on its quality in the plasma of tokamak and especially in reducing the anomalous transport in TEXT and ITER, then we study the influence of perturbation’s modes in the particles diffusion. In the whole simulations, a comparison between results obtained using ITER and TEXT parameters is carried out.The reversed magnetic shear is the most important factor in the studies of the plasmas of tokamak. In this paper we focus our research, at first stage, on the control of the improved confinement regimes by studying the influence of reversed shear on its quality in the plasma of tokamak and especially in reducing the anomalous transport in TEXT and ITER, then we study the influence of perturbation’s modes in the particles diffusion. In the whole simulations, a comparison between results obtained using ITER and TEXT parameters is carried out

Modelling of Collision in the Plasma Sheath and the Cathode Erosion of Electrical Arc

In order to improve many industrial applications of the plasma sheath and the cathode erosion of electrical arc, the prime objective of this paper is to treat the modelling and simulation of the effects of ions collisionality on the plasma sheath and to determine the collisional dependence of the sheath width and the ion impact energy on the wall using the Runge-Kutta Routrine on the presence or the absence of the term source in the continuity equation . Then , to explain the dependence of the measured erosion rate of the cathode by considering the cathode spot heat balance equation coupled with equation obtained from the sheath and taking into account the physical phenomena such as ion and electron fluxes, radiation, thermal conductivity and evaporation.In order to improve many industrial applications of the plasma sheath and the cathode erosion of electrical arc, the prime objective of this paper is to treat the modelling and simulation of the effects of ions collisionality on the plasma sheath and to determine the collisional dependence of the sheath width and the ion impact energy on the wall using the Runge-Kutta Routrine on the presence or the absence of the term source in the continuity equation . Then , to explain the dependence of the measured erosion rate of the cathode by considering the cathode spot heat balance equation coupled with equation obtained from the sheath and taking into account the physical phenomena such as ion and electron fluxes, radiation, thermal conductivity and evaporation

Hes1 and Hes5 activities are required for the normal development of the hair cells in the mammalian inner ear.

The mammalian inner ear contains two sensory organs, the cochlea and vestibule. Their sensory neuroepithelia are characterized by a mosaic of hair cells and supporting cells. Cochlear hair cells differentiate in four rows: a single row of inner hair cells (IHCs) and three rows of outer hair cells (OHCs). Recent studies have shown that Math1, a mammalian homolog of Drosophila atonal is a positive regulator of hair cell differentiation. The basic helix-loop-helix (bHLH) genes Hes1 and Hes5 (mammalian hairy and Enhancer-of-split homologs) can influence cell fate determination by acting as negative regulators to inhibit the action of bHLH-positive regulators. We show by using reverse transcription-PCR analysis that Hes1, Hes5, and Math1 are expressed in the developing mouse cochleae. In situ hybridization revealed a widespread expression of Hes1 in the greater epithelial ridge (GER) and in lesser epithelial ridge (LER) regions. Hes5 is predominantly expressed in the LER, in supporting cells, and in a narrow band of cells within the GER. Examination of cochleae from Hes1(-/-) mice showed a significant increase in the number of IHCs, whereas cochleae from Hes5(-/-) mice showed a significant increase in the number of OHCs. In the vestibular system, targeted deletion of Hes1 and to a lesser extent Hes5 lead to formation of supernumerary hair cells in the saccule and utricle. The supernumerary hair cells in the mutant mice showed an upregulation of Math1. These data indicate that Hes1 and Hes5 participate together for the control of inner ear hair cell production, likely through the negative regulation of Math1

Ecological insights and conservation imperatives for Laurus azorica in Morocco

The Azores laurel Laurus azorica (Seub.) Franco is a highly esteemed forest species in Morocco due to its medicinal and aromatic properties. However, the natural habitats of this species are increasingly scarce, resulting in its classification as a rare species. This study comprehensively investigates the autoecology, plant communities, and distribution patterns of L. azorica, aiming to discern the crucial ecological factors underpinning its survival and shed light on its conservation status. Field surveys, including floristic relevés and environmental characterization, were conducted to identify the primary plant communities hosting remnants of L. azorica. Fieldwork and ecological analysis reveal five distinct plant communities associated with L. azorica: low elevation thermophilic holm oak woodland, mesophilic mid-altitude holm oak woodland, Quercus faginea, deciduous broadleaf mountain and Cytisus balansae plant communities. The study emphasizes the importance of ecological requirements such as oceanic exposure, rainfall, temperature, and forest mull soils in creating suitable habitats for L. azorica populations. Currently, L. azorica populations in Morocco are represented by small trees, shrubs, or bushes, often exhibiting distorted and damaged structures due to unregulated pruning. Natural regeneration of the species is completely absent. The value chain associated with L. azorica is limited, involving informal harvesters, intermediary herbalist grocers, and final consumers, due to the lack of a legal framework for resource evaluation caused by its severe depletion. To secure the survival of L. azorica in Morocco, it is crucial to address gaps in legislation, intensify conservation efforts, and promote sustainable development practices. Protecting and restoring the natural habitats of the species, along with implementing responsible harvesting practices, are essential steps towards conserving this valuable forest species