Estimation of thermally stimulated current in as grown TlGaSeS layered single crystals by multilayered perceptron neural network

This paper presents an artificial neural network approach to compute thermally stimulated current (TSC) in as-grown TlGaSeS layered single crystals. The experimental data have been obtained from TSC measurements. The network has been trained by a genetic algorithm (GA). The results confirmed that the proposed model could provide an accurate computation of the TSC.     

Time-varying sliding-coefficient-based decoupled terminal sliding-mode control for a class of fourth-order systems

A time-varying sliding-coefficient-based decoupled terminal sliding mode control strategy is presented for a class of fourth-order systems. First, the fourth-order system is decoupled into two second-order subsystems. The sliding surface of each subsystem was designed by utilizing time-varying coefficients. Then, the control target of one subsystem to another subsystem was embedded. Thereafter, a terminal sliding mode control method was utilized to make both subsystems converge to their equilibrium points in finite time. The simulation results on the inverted pendulum system demonstrate that the proposed method exhibits a considerable improvement in terms of a faster dynamic response and lower IAE and ITAE values as compared with the existing decoupled control methods.     

Scattering of inhomogeneous plane waves by a truncated cylindrical cap

Scattered fields of the inhomogeneous plane waves from a truncated cylindrical cap are obtained. Also the uniform diffracted fields are performed in terms of the Fresnel functions. Reflected and diffracted fields are obtained by using the physical optics and the geometrical theory of diffraction methods, respectively. All the mentioned results are plotted numerically for various numerical parameters.     

A comprehensive evaluation of mimosa extract as a corrosion inhibitor on AA6060 alloy in acid rain solution: part I. Electrochemical AC methods

The inhibition effect of mimosa extract on the corrosion of AA6060 aluminum alloy in acid rain solution was investigated by electrochemical impedance spectroscopy and dynamic electrochemical impedance spectroscopy (DEIS). All the studied electrochemical parameters showed good corrosion inhibitive characteristics with respect to the aluminum alloy in the tested solution. Inhibitor efficiency increased with the concentration and attained 45% at 2750 ppm. The advantage of DEIS as a tool for the investigation of corrosion inhibitor influence was discussed.     

A solid-state dye-sensitized solar cell based on a novel ionic liquid gel and ZnO nanoparticles on a flexible polymer substrate

This paper describes a new strategy to make a full solid-state, flexible, dye-sensitized solar cell (DSSC) based on novel ionic liquid gel, organic dye, ZnO nanoparticles and carbon nanotube (CNT) thin film stamped onto a polyethylene terephthalate (PET) substrate. The CNTs serve both as the charge collector and as scaffolds for the growth of ZnO nanoparticles, where the black dye molecules are anchored. It opens up the possibility of developing a continuous roll to roll processing for THE mass production of DSSCs.     

Phytochemical Characterization of Phagnalon graecum Boiss. by HPLC and GC-MS with its Enzyme Inhibitory and Antioxidant Activity Profiling by Spectrophotometric Methods

In the current study, the n-hexane, chloroform, ethyl acetate, methanol, and water extracts of Phagnalon graecum Boiss. (Asteraceae), a spice plant, were investigated for their enzyme inhibitory activity against acetylcholinesterase, butyrylcholinesterase, lipoxygenase, tyrosinase, and antioxidant activities. Antioxidant activity of the extracts was determined by 2,2-diphenyl-1-picrylhydrazyl radical scavenging, ferric ion-chelation activity, and ferric-reducing antioxidant power tests. Total phenol (gallic acid equivalent) and flavonoid (quercetin equivalent) contents were calculated. Essential oil of the plant was analyzed by GC-MS, while the selected phenolic acids were analyzed by HPLC. The extracts had insignificant inhibition against the tested enzymes, whereas they displayed a remarkable antioxidant activity. Therefore, to the best of our knowledge, this study presents the first data on biological activity and phytochemical content of P. graecum and this species could be utilized as potential antioxidant applicable for food preservation.     

Evaluation of corrosion inhibition of brass-118 in artificial seawater by benzotriazole using Dynamic EIS

The paper presents the results of corrosion behaviour of brass-118 in artificial seawater and the inhibitor effect of benzotriazole (BTA) by using a novel method called dynamic electrochemical impedance spectroscopy (DEIS). This method allows the tracing of the dynamics of the corrosion and the inhibition process based on the evaluation of electrical parameters of the equivalent circuit. Instantaneous impedance spectra recorded up to 10 h show that an exposure of few hours is not enough for the determination of inhibition efficiency. The results indicate the usefulness of DEIS technique in the field of inhibitor research.     

Electrical and Structural Properties of RE<Subscript>3</Subscript>Ba<Subscript>5</Subscript>Cu<Subscript>8</Subscript>O<Subscript>18</Subscript> (RE=Y,Sm and Nd) Superconductors

This paper presents the synthesis and characterization of the new superconducting compounds with nominal composition, RE₃Ba₅Cu₈O₁₈, RE=Y, Sm and Nd. The onset critical temperatures of the present samples are 97.5, 97 and 95 K for the RE=Y, Sm and Nd, respectively. The first two values are the highest for the RE–Ba–Cu–O superconductors recorded to date. The RE₃Ba₅Cu₈O₁₈ samples crystallize in the orthorhombic system, with increased unit cell volume as Sm and Nd replace the element Y.     

Vertically aligned carbon nanotube – Polyaniline nanocomposite supercapacitor electrodes

We develop a fast and cost effective method for the fabrication of a nanocomposite supercapacitor electrode. In this study aluminum foils were decorated with vertically aligned carbon nanotubes (VACNT) via chemical vapor deposition (CVD) method, which was followed by the electrodeposition of polyaniline (PANI) layer on top of the VACNTs. Electrochemical behavior of the fabricated nanocomposite electrodes were evaluated through cyclic voltammetry, galvanostatic charge discharge cycles and electrochemical impedance spectroscopy method. Fabricated VACNT/PANI nanocomposite electrodes through 15 electrodeposition cycles showed significant electrochemical performance. The specific capacity of these electrodes was calculated as 16.17 mF/cm² at a current density of 0.25 mA/cm².     

Voltage-induced dependence of Raman-active modes in single-wall carbon nanotube thin films

We report on electrical Raman measurements in transparent and conducting single-wall carbon nanotube (SWNT) thin films. Application of external voltage results in downshifts of the D and G modes and in reduction of their intensity. The intensities of the radial breathing modes increase with external electric field related to the application of the external voltage in metallic SWNTs, while decreasing in semiconducting SWNTs. A model explaining the phenomenon in terms of both direct and indirect (Joule heating) effects of the field is proposed. Our work rules out the elimination of large amounts of metallic SWNTs in thin film transistors using high field pulses. Our results support the existence of Kohn anomalies in the Raman-active optical branches of metallic graphitic materials.