The dynamical behaviors of the proposed autonomous jerk oscillator with sine nonlinearity (AJOSN) and its application to secure s-EMG (Surface ElectroMyoGraphic) data are discussed in this paper. The AJOSN has two or no-equilibrium points and the stability of the two equilibrium points shows that one of the equilibrium points is stable while the other is unstable. The AJOSN reveals fast-spiking and periodic bursting, relaxing and periodic oscillations, hidden chaotic attractors and coexisting attractors. The numerical analysis results are validated by the Field Programmable Gate Array (FPGA) implementation. Finally, the AJOSN's chaotic behavior coupled with the logistic map is exploited to encrypt the s-EMG signals. To improve security, the proposed encryption and decryption algorithm encrypts the s-EMG signal twice at the same time. After being converted to 2D in the form of a grayscale image, the s-EMG signal is encrypted for the first time using the chaotic signal generated by the AJOSN. The resulting encrypted signal is called to as "encrypted signal jerk." The chaotic logistics map is used to encrypt the final signal. The resulting encrypted signal is therefore the end product of the proposed encryption technique. The encryption and decryption results obtained are quite encouraging and offer a great prospect.

This paper explores the dynamics and electronic validations of a memristive Helmholtz snap oscillator (MHSO), employing it to model a process of pseudo-random number generator (PRNG). The MHSO depicts two lines of equilibrium points. Characterizing the stability of the equilibrium domains, Hopf bifurcation is associated with one of the equilibrium domains while the other region of equilibrium points is always unstable. Extreme multistability features, hidden complex attractors, antimonotonicity, period-3-oscillations and complex hidden attractors coexisting, chaotic bubbles, and hidden attractors are generated in MHSO for particular values of parameters. Electronic validations of MHSO based on OrCAD-PSpice software and microcontroller reveal that OrCAD-PSpice and microcontroller dynamics agree well with the dynamics achieved by numerical simulations. Lastly, the chaotic characteristics depicted by the MHSO are used to design a process of PRNG. The generated random bits are validated successfully by a standard statistical tool set by the National Institute of Standards and Technology (NIST-800-22).

Cu2Zn1−yFeySnS4-based solar cells with different mole fractions of iron have been analyzed using numerical simulations in this study. The analysis deals with the effect of the iron content on the overall electrical performance of solar cells. Results revealed that the Voc is affected by the increase of the iron content even if it improves the other parameters. We found that the CZFTS solar cell with a mole fraction of iron equal to 1 (CFTS) showed the best results in terms of power conversion efficiency (PCE). Moreover, variations of several structural and physical parameters of the buffer CdS and the best absorber CFTS on the overall electrical characteristics of the cell were investigated. Simulations showed promising results with PCE of 20.35%, Jsc of 26.09 mA/cm2, Voc of 0.93 V, and FF of 83.93%. The results obtained can serve as a basis for the design and manufacture of high-efficiency CZFTS solar cells.

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