Uporaba magnetskog smika za poboljšanje zadržavanja plazme u tokomaku

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

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

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

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

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

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

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

Patient-tailored risk assessment of obstructive coronary artery disease using Rubidium-82 PET-based myocardial flow quantification with visual interpretation

Introduction: Our aim was to estimate the probability of obstructive CAD (oCAD) for an individual patient as a function of the myocardial flow reserve (MFR) measured with Rubidium-82 (Rb-82) PET in patients with a visually normal or abnormal scan. Materials and Methods: We included 1519 consecutive patients without a prior history of CAD referred for rest-stress Rb-82 PET/CT. All images were visually assessed by two experts and classified as normal or abnormal. We estimated the probability of oCAD for visually normal scans and scans with small (5%–10%) or larger defects (&gt; 10%) as function of MFR. The primary endpoint was oCAD on invasive coronary angiography, when available. Results: 1259 scans were classified as normal, 136 with a small defect and 136 with a larger defect. For the normal scans, the probability of oCAD increased exponentially from 1% to 10% when segmental MFR decreased from 2.1 to 1.3. For scans with small defects, the probability increased from 13% to 40% and for larger defects from 45% to &gt; 70% when segmental MFR decreased from 2.1 to 0.7. Conclusion: Patients with &gt; 10% risk of oCAD can be distinguished from patients with &lt; 10% risk based on visual PET interpretation only. However, there is a strong dependence of MFR on patient’s individual risk of oCAD. Hence, combining both visual interpretation and MFR results in a better individual risk assessment which may impact treatment strategy.</p