High-performance a-IGZO-based flexible TTFT with stacked dielectric layers via ultrathin high-κ SrTiO3 buffer layer grown on HfO2

Journal of Materials Science: Materials in Electronics - In this study, ITO-coated PET was used as the substrate to create a flexible and transparent structure. a-IGZO (amorphous InGaZnO4) is...     

Magnetic field enhancement of electrochemical hydrogen evolution reaction probed by magneto-optics

External magnetic fields affect various electrochemical processes and can be used to enhance the efficiency of the electrochemical water splitting reaction. However, the driving forces behind this effect are poorly understood due to the analytical challenges of the available interface-sensitive techniques. Here, we present a set-up based on magneto- and electro-optical probing, which allows to juxtapose the magnetic properties of the electrode with the electrochemical current densities in situ at various applied potentials and magnetic fields. On the example of an archetypal hydrogen evolution catalyst, Pt (in a form of Co/Pt superlattice), we provide evidence that a magnetic field acts on the electrochemical double layer affecting the local concentration gradient of hydroxide ions, which simultaneously affects the magneto-optical and magnetocurrent response.     

Advanced controller design based on gain and phase margin for microgrid containing PV/WTG/Fuel cell/Electrolyzer/BESS

Nowadays, with the increase in the amount of power generation related to renewable energy resources, the need for energy storage and management is raised. In this regard, the hydrogen energy plays a critical role in the development of renewable technologies. In view of the above, advanced controller design is presented in this paper to effectively perform load frequency control of islanded fuel cell microgrid based on the wind turbine, photovoltaic, fuel cell, electrolyzer, battery energy storage systems, and residential and commercial loads. The controller design is based on the determination of the controller parameters that the fuel cell microgrid system will provide the desired dynamic properties. In the proposed controller design, virtual gain and phase margin testers are added to provide the desired dynamic properties. The controller's stable parameter plane is determined with the help of the stability boundary locus method, taking into account time delay, gain, and phase margin. First, the accuracy of the stable parameter plane determined for the proposed controller design is demonstrated by means of time domain and eigenvalue analyzes. Finally, in order to show the performance of the advanced controller design and the success of the fuel cell as a backup generator, analysis studies have been carried out using actual data of solar and wind, and appropriate changes of load in studied microgrid.     

A deep learning-based CEP rule extraction framework for IoT data

The Journal of Supercomputing - With the recent developments in Internet of Things (IoT), the number of sensors that generate raw data with high velocity, variety, and volume is tremendously...     

Advanced Friction–Wear Behavior of Organic Brake Pads Using a Newly Developed System

The objective of this study was to investigate the influence of an advanced performance system on the tribological behavior of brake pad material using a specially designed brake pad tester system following standard SAE J-661. The tribological behavior and friction and wear characteristics of the organic brake pad samples were evaluated. During braking tests, the samples, in contact with a cast iron disk, were studied at different disc speeds, temperatures, and braking cycles under a constant pressure. In order to understand the friction and wear behavior, the unworn surfaces, worn surfaces, and wear debris were characterized by means of scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). Furthermore, the surface characteristics and differences in the wear modes of the brake pad samples were examined. Wear debris was permitted to deform the brake pad surfaces, leading to friction layers and enabling the estimation of the friction behavior of the brake pads. The results showed that the best friction–wear behavior was obtained with lower braking cycles at low speeds and temperature. Thus, the newly developed brake pad tester system proved very effective in evaluating the performance of the brake pad samples.     

Enhancing stability region of time‐delayed smart power grids by non‐integer controllers

In this study, the impacts of non‐integer order controller on the stable parameter space of the microgrid (MG) frequency control system with fixed communication time delay are investigated and discussed with the help of the stability boundary locus (SBL) method. This study proposes a non‐integer order controller for the load frequency control (LFC) of the MG systems. To that end, the load frequency model of the MG is formulated and then the characteristic equations of this model are obtained. Then, with the help of this characteristic equation, the stable parameter space of the non‐integer controller is determined with regard to different time delay (τ ) and fractional integral order values (α ) using the SBL method. In order to show the accuracy of the obtained stable parameter space, time domain and generalized modified Mikhailov (GMM) criterion studies are carried out for different values of (τ ) and (α ). According to the results obtained, the areas of stable parameter space according to different α values and τ = 1.6 are calculated as 444.8860 for α = 0.4 , 342.9728 for α = 0.7 , 259.3578 for α = 1 , 216.2541 for α = 1.3 and 159.6826 for α = 1.6 . In addition, the areas of stable parameter space according to different τ values and α = 1.4 are calculated as 784.5222 for τ = 1 , 106.3219 for τ = 2 , 29.6959 for τ = 3 and 11.5946 for τ = 4 . Despite the extreme variability arising from nature of resources that make up the MG, the designed non integer order controller with the values selected within the stable parameter space stably carries out LFC control of the MG.     

LU triangularization extreme learning machine in EEG cognitive task classification

Neural Computing and Applications - Electroencephalography (EEG) has been used as a promising tool for investigation of brain activity during cognitive processes. The aim of this study is to reveal...     

Exact Analysis of Non-Linear Fractionalized Jeffrey Fluid. A Novel Approach of Atangana-Baleanu Fractional Model

It is a very difficult task for the researchers to find the exact solutions to mathematical problems that contain non-linear terms in the equation. Therefore, this article aims to investigate the viscous dissipation (VD) effect on the fractional model of Jeffrey fluid over a heated vertical flat plate that suddenly moves in its own plane. Based on the Atangana-Baleanu operator, the fractional model is developed from the fractional constitutive equations. VD is responsible for the non-linear behavior in the problem. Upon taking the Laplace and Fourier sine transforms, exact expressions have been obtained for momentum and energy equations. The influence of relative parameters on fluid flow and temperature distribution is shown graphically. As special cases, and for the sake of correctness, the corresponding results for second-grade fluid and Newtonian viscous fluid are also obtained. It is interesting to note that fractional parameter α provides more than one line as compared to the classical model. This effect represents the memory effect in the fluid which is not possible to elaborate by the classical model. It is also worth noting that the temperature profile of the generalized Jeffrey fluid rises for higher values of Eckert number which is due to the enthalpy difference of the boundary layer.     

Phase transformation kinetics and microstructure of NiTi shape memory alloy: effect of hydrostatic pressure

The effect of hydrostatic pressure on the behaviour of reverse and forward transformation temperatures and physical properties of NiTi shape memory alloy has been investigated. The transformation temperatures and physical properties of the alloy change with applied pressure. It has been clearly seen from differential scanning calorimetry that with the increase of applied pressure, while \(A_\mathrm{s},\, A_\mathrm{f}\) and \(M_\mathrm{f}\) transformation temperatures decrease, \(M_\mathrm{s}\) value increases. Moreover, it is obvious that with the increase of applied pressure, Gibbs free energy increases by 5.2883 J, while elastic energy increases by 1.4687 J. In addition, entropy of the alloys decreases by 0.2335 J \((\hbox {g }{^{\circ }}\!\hbox { C})^{-1}\) with applied pressure. Additionally, it is evident from the scanning electron microscopy images of the samples that there is an obvious difference in the grain sizes of the unpressured sample and the samples on which pressure is applied, the sizes being 10–100 and 30–150 \(\upmu \!\hbox {m}\), respectively.     

Novel Analytical Thermal Performance Rate Analysis in ZnO-SAE50 Nanolubricant: Nonlinear Mathematical Model

The investigation of local thermal transport rate in the nanolubricants is significant. These lubricants are broadly used in environmental pollution, mechanical engineering and in the paint industry due to high thermal performance rate. Therefore, thermal transport in ZnO-SAE50 nanolubricant under the impacts of heat generation/absorption is conducted. The colloidal suspension is flowing between parallel stretching disks in which the lower disk is positioned at z = 0 and upper disk apart from distance d. The problem is transformed in dimensionless version via described similarity transforms. In the next stage, an analytical technique (VPM) is implemented for the solution purpose. The graphical results against multiple flow parameters were furnished over the region of interest and explained comprehensively. It is imperative to mention that the results are plotted for ZnO-SAE50 and conventional liquid as well. Further, rapid motion of the fluid is perceived against high Reynolds and γ parameters. The wall shear stresses at the upper end rises for multiple Reynolds and γ while; decrement is detected at the lower end. The significant contribution of an internal heat source is noted for thermal performance rate at the upper end. Foremost, the local heat transport rate declines at the lower disk. By altering Reynolds number, prompt heat transfer rate is gained at the upper disk and increasing behavior of the local heat transport rate is slow at the lower disk. From the study, it is concluded that the nanolubricants have high thermal characteristics. Therefore, such fluids are reliable to use in above stated areas.