First-order Fermi acceleration processes at ultrarelativistic (γ ∼ 5−30) shock waves are studied with the method of Monte Carlo simulations. The accelerated particle spectra are derived by integrating the exact particle trajectories in a turbulent magnetic field near the shock. The magnetic field model upstream of the shock assumes finite-amplitude perturbations within a wide wavevector range a...

aims: arsenic contamination of natural water resources has become an important environmental problem in the world. the adsorption method by iron filings adsorbent or zero-valent iron was used. the study aimed to evaluate the efficiency of iron filings in arsenite removal from polluted water and to investigate the effect of magnetic field on the process. materials & methods: this interventional ...

in order to compare effect of magnetic field and frigate surfactant to enhance the efficacy of iodosulfuron-methyl-sodium plus mesosulfuron-methyl (chevalier) to control wild oat, a greenhouse experiment of dose-response was conducted. treatments were 0, 3, 6, 12, 18 and 24 doses g a.i. ha-1 of chevalier (i) without treatment, (ii) with frigate % 0.1 v/v, (iii) with magnetic field, and (iv) fri...

in this study, the effects of strength and direction of the magnetic field on lid-driven cavity flow in the whole range of magnetic field strength variations, which already used in practice up to present (0 to 10 tesla), are studied. the governing equations, including conservative equations of momentum, continuity and magnetic field equations were solved numerically. momentum and continuity equ...

background: hydatidosis it is a zoonotic disease which is caused by the larval stages of different species of the tapeworms (cestoda) of genus echinococcus. currently, the surgery is most definitive method of treatment for hydatid cyst, but always there is the risk of leakage or rupture during the surgery, therefore it is considered unreliable method. methods: protoscoleces of hydatid cysts wer...

An analysis of entropy generation in an MHD boundary layer flow of a viscous incompressible electrically conducting fluid past an inclined flat plate embedded in a porous media in a rotating system with Hall currents has been presented. The governing equations describing the flow have been solved analytically. The velocity field, induced magnetic field, shear stress and bulk temperature in the ...

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Small-scale fluctuations of magnetic field and velocity may be responsible for the Stokes asymmetries observed in all photospheric magnetic structures (the MISMA hypothesis). We support the hypothesis showing that atmospheres with optically-thin micro-structure reproduce the polarization of Fe I λ6301.5 Å and Fe I λ6302.5 Å observed in a sunspot. Ten thousand spectra were fitted by model MISMAs...

We interpret penumbral filaments as due to convection in field-free, radially aligned gaps just below the visible surface of the penumbra, intruding into a nearly potential field above. This solves the classical discrepancy between the large heat flux and the low vertical velocities observed in the penumbra. The presence of the gaps causes strong small-scale fluctuations in inclination, azimuth...