131 research outputs found

    Uporaba magnetskog smika za poboljšanje zadržavanja plazme u tokomaku

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    We investigate the influence of reversed shear on the improvement of the confinement\u27s quality in the plasma of a tokamak, specifically in reducing the anomalous transport. We use a special model for the drift wave fields. Comparison between the particle trajectories for normal and reversed shear is carried out in 2D and 3D presentation. The diffusion coefficient of particles and the radial electric field for the two cases, normal and negative shear, have been evaluated.Proučavamo utjecaj obrnutog smika za poboljšanje zadržavanja plazme u tokomaku, posebice za smanjenje anomalnog prijenosa. Primijenili smo poseban model za posmična valna polja. Usporedbu putanja čestica za normalan i obrnuti posmik načinili smo u 2D i 3D prostoru. Također smo odredili difuzijske koeficijente za čestice i radijalno električno polje za dva slučaja, normalan i obrnuti posmik

    Uporaba magnetskog smika za poboljšanje zadržavanja plazme u tokomaku

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    We investigate the influence of reversed shear on the improvement of the confinement\u27s quality in the plasma of a tokamak, specifically in reducing the anomalous transport. We use a special model for the drift wave fields. Comparison between the particle trajectories for normal and reversed shear is carried out in 2D and 3D presentation. The diffusion coefficient of particles and the radial electric field for the two cases, normal and negative shear, have been evaluated.Proučavamo utjecaj obrnutog smika za poboljšanje zadržavanja plazme u tokomaku, posebice za smanjenje anomalnog prijenosa. Primijenili smo poseban model za posmična valna polja. Usporedbu putanja čestica za normalan i obrnuti posmik načinili smo u 2D i 3D prostoru. Također smo odredili difuzijske koeficijente za čestice i radijalno električno polje za dva slučaja, normalan i obrnuti posmik

    THE INFLUENCES OF MAGNETIC SHEAR ON THE IMPROVEMENT OF THE QUALITY OF CONFINEMENT IN THE PLASMA OF TOKAMAK

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    In this paper we have studied the influence of reversed shear on the improvement of the confinement’s quality in the plasma of tokamak and especially in reducing the anomalous transport. For that, we have used a special model for the drift wave fields. Comparison between particles trajectories for normal and reversed shear is carried out in 2D and 3D presentation. Also, the diffusion coefficient of particles for the two cases, normal and negative shear, is evaluated.In this paper we have studied the influence of reversed shear on the improvement of the confinement’s quality in the plasma of tokamak and especially in reducing the anomalous transport. For that, we have used a special model for the drift wave fields. Comparison between particles trajectories for normal and reversed shear is carried out in 2D and 3D presentation. Also, the diffusion coefficient of particles for the two cases, normal and negative shear, is evaluated

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

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    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

    The physical problem and the modelling of the sheath in collisional dusty plasma

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    The aim of this paper is to study the behaviour of sheath structure in plasma with collisions, and simulation of the effects of collisionality on the plasma sheath using the Runge-Kutta routine. We consider the near-wall region of an unmagnetized dusty plasma which consists of electrons, ions, micron-size dust particles and neutral particles. Since the dust particles are much heavier than electrons and ions, the latter are assumed to be out of thermal equilibrium with dust as a cold fluid. The neutrals are taken as immobile. Precise numerical solutions of the model are used to determine the collisional dependence of the sheath width and the impact energy at the wall

    The physical problem and the modelling of the sheath in collisional dusty plasma

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    The aim of this paper is to study the behaviour of sheath structure in plasma with collisions, and simulation of the effects of collisionality on the plasma sheath using the Runge-Kutta routine. We consider the near-wall region of an unmagnetized dusty plasma which consists of electrons, ions, micron-size dust particles and neutral particles. Since the dust particles are much heavier than electrons and ions, the latter are assumed to be out of thermal equilibrium with dust as a cold fluid. The neutrals are taken as immobile. Precise numerical solutions of the model are used to determine the collisional dependence of the sheath width and the impact energy at the wall

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

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    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

    Comparative pathogenicity of Colletotrichum spp. against different varieties of strawberry plants (Fragaria ananassa) widely grown in Morocco

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    The evolution of anthracnose symptoms on the aerial part (leaves, stems and strawberries) of three varieties Fortuna, Camarosa and Festival of strawberry plants inoculated with the conidial suspensions of Colletotrichum acutatum and Colletotrichum gloeosporioides isolates was followed. The severity index and infection coefficients increased in function of time. Seven days after inoculation they were low not exceeding 13.43% and 43.33, but they increased four weeks after inoculation, respectively, to 37.96% and 99 on strawberry plants of the Camarosa variety, 54.44% and 105 on those of Fortuna and 51.12% and 85 on those of Festival. At the sixth week, the severity index and infection coefficients became very high, reaching respectively 100% and 408 on Fortuna plants inoculated with C. gloeosporioides isolate (Coll3) followed by Coll2 (89.28% – 300), Coll1 (86.66% – 378) and Coll4 (80.45% – 198) of C. acutatum species. Similarly, the isolate Coll3 caused fruit rot; the percentage of rotten strawberries was 100% on Fortuna variety, 83.33% on Festival and 70.25% on Camarosa. A positive re-isolation of the tested Colletotrichum isolates has been noted from leaves of strawberry varieties and negative from crowns or the roots. A significant to moderate reduction in fresh and dry weights of the aerial part and roots was noted in inoculated strawberry plants compared to the control

    ゲンショク キョウイン ニ タイスル GIS キョウイク ソノ コウソウ

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    鳴門教育大学情報処理センターを利用して現職教員に対して提供するGIS教育 (講習会) について計画した (表1)。講習会は2部 (A・B) 構成で、全体として終日 (実質6時間程度) 2日間であるが、A・Bは相対的に独立したものなのでいずれかのみを受講することもできる。Aは現在の地図教育の延長上で学校教育に直ちに適用可能な技能として MANDARA と Kashmir とを取り上げその操作法を説明する。BはGISへの関心を喚起することも含みつつ将来のGIS導入に備えた予備的な技能として ArcVie を用いてGISについて解説する。それぞれ講義と実習とからなる。国立情報学研究所『研究紀要公開支援事業』により電子化

    Disappearance of Azoxystrobin and difenoconazole in green beans cultivated in Souss Massa valley (Morocco)

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    A study was undertaken to evaluate the degradation behavior and residue levels of azoxystrobin and difenoconazole in Belma green beans variety grown in an experimental plastic greenhouse. The measurements were made over a 3 week period in which up to two successive treatments with azoxystrobin and a 5 week period in which up to two successive treatments with difenoconazole were carried out. Residue levels of dicofol and difenoconazole were determined by Gas chromatography with electron capture detection (GC-ECD), liquid-liquid extraction (LLE), solid phase extraction (SPE) and high-performance liquid chromatography (HPLC). During the study, residue levels in the plantation ranged between 0.35 and 0.01 mg/kg for azoxystrobin and between 0.25 and 0.01 mg/kg for difenoconazole. The residual concentrations after the preharvest intervals (PHI) were below the legal limits
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