The hydrochemical and multivariate statistical techniques such as the principal component analysis (PCA) and the cluster analysis (CA) were used to identify the hydrochemical processes and their relation with groundwater quality and also to get an insight into the hydrochemical Zana aquifer groundwater chemistry evaluation. Twenty-four samples during the wet season and even during the dry season are analyzed. The Piper diagram showed that water facies are magnesium bicarbonate on the sides of the western reliefs and magnesium chloride-sulfated at the north and the center of the plain. The PCA carried out on three factors revealed that on the factorial design F1-F3, nitrates negatively determine factor 3, indicating the presence of an agriculture pollution. On the factorial design F1-F2, HCO3- positively determine the factor 2, indicating the carbonated origin. However, the CA, based on variables, showed that the waters in the region can be classified into three groups according to flow direction while the CA, based on major ion contents, defined three groups, reflecting the same hydrochemical facies. The first group with dry residue varying between 360 and 1700 mg/l and characterized by Mg2+ and Cl-, HCO3-. Samples of this group are mostly located in the north and northeastern part of the region. The second group with highest dry residue (2080 to 3820 mg/l) characterized by Mg2+ and SO4-, Cl- is located near the Northwestern and western outcrops. The third group coincides with the central part, the lowest of the plain, with heightened dry residue (4140 to 13,950 mg/l), characterized by Mg2+ and SO4-. The hydrochemical study made it possible to allot the evaporitic origin to the elements Na+, Mg2+, K+, Cl-, and SO4-, while for element HCO3-, it results from the carbonated formations. These results showed that the presence of nitrates in the studied area is closely linked to the agricultural activity.

In this paper, a new radiation sensitive field-effect Transistor (RADFET) dosimeter design based on armchair-edge graphene nanoribbon (AGNR), for high performance low-dose monitoring applications, is proposed through a quantum simulation study. The simulation approach used to investigate the proposed nanoscale RADFET is based on solving the Schrödinger equation using the mode space (MS) non-equilibrium Green’s function (NEGF) formalism coupled self-consistently with a two dimensional (2D) Poisson equation under the ballistic limits. The responsiveness of the proposed RADFET to the modulation of radiation-induced trapped charge densities is reflected via the threshold voltage, which is considered as a sensing parameter. The dosimeter behavior is investigated, and the impact of variation in physical and geometrical parameters on the dosimeter sensitivity is also studied. In comparison to other RADFETs designs, the proposed radiation sensor provides higher sensitivity and better scalability, which are the main requirements for futuristic dosimeters. The obtained results make the suggested RADFET dosimeter as a viable and attractive replacement to silicon-based MOS dosimeters.

In this paper, we present a comprehensive investigation the impact of various high-k gate materials on both breakdown voltage and drain current of a vertical 4H-SiC-based power MOSFET, operating in the quasi-saturation regime. The device electrical behavior is numerically investigated using a TCAD-based computation provided by ATLAS 2D simulator. Moreover, the performance parameters, governing the power MOSFET breakdown characteristics are extracted in order to reveal the role of the high-k gate materials in improving the transistor electrical performance. The effect of the dielectric permittivity on the derived current capability in also analyzed. After, we conduct a sensitivity analysis of the breakdown voltage with several high-k materials (Al2O3, HfSiO4, HfO2, and TiO2) and different dielectric thicknesses. It is found that the proposed power MOSFET design exhibits improved electrical behavior not only enables enhancing the drain current but also allows achieving superior breakdown performance as compared to the conventional design, making it suitable for high-performance power electronic applications.

In this work, we present a new techniques to solve the integral equations of the second kind with logarithmic kernel. First, we show the existence and uniqueness of the solution for the given problem in a Hilbert space. Next, we discuss a projection method for solving integral equations with logarithmic kernel of the second kind; the present method based on the shifted Legendre polynomials. We examine the existence of the solution for the approximate equation, and we provide a new error estimate for the numerical solutions. At the end, numerical examples are provided to illustrate the theoretical results.