In this paper, we first introduce a new class of bilevel weak vector variational inequality problems in locally convex Hausdorff topological vector spaces. Then, using the Kakutani-Fan-Glicksberg fixed-point theorem, we establish some existence conditions of the solution for this problem.

The study aims to investigate the possibility of processing copper metal (Cu2+) with activated carbon prepared from macadamia shell. Activated carbon is prepared from Macadamia shell by chemical agent H3PO4 with coke ratio: H3PO4 = 1:1, optimal temperature condition is 5000C and burning time is 60 minutes. Using the assumed Cu2+ metal treats materials in the laboratory with a concentration of 30ppm. The research to result ability material adsorbed Cu2+ metal achieve good performance 95.92% handle, corresponding to the concentration of Cu2+ reduced from 30 mg/l to 1.2mg/l in optimal conditions is pH = 4.5 , dosage 1.8g/l, time 30 minutes. The results showed that activated carbon prepared from macadamia husk with chemical agent H3PO4 was capable of treating copper metal in wastewater.

In this paper, we study a class of parametric vector mixed quasivariational inequality problem of the Minty type (in short, (MQVIP)). Afterward, we establish some sufficient conditions for the stability properties such as the inner-openness, lower semicontinuity and Hausdorff lower semicontinuity of the solution mapping for this problem. The results presented in this paper is new and wide to the corresponding results in the literature

In this article, a class of Hindmarsh-Rose model is studied. First, all necessary conditions for the parameters of system are found in order to have one stable fixed point which presents the resting state for this famous model. After that, using the Hopf’s theorem proofs analytically the existence of a Hopf bifurcation, which is a critical point where a system’s stability switches and a periodic solution arises. More precisely, it is a local bifurcation in which a fixed point of a dynamical system loses stability, as a pair of complex conjugate eigenvalues cross the complex plane imaginary axis. Moreover, with the suitable assumptions for the dynamical system, a small-amplitude limit cycle branches from the fixed point.