Novel electrospun polymer electrolytes incorporated with Keggin‐type hetero polyoxometalate fillers as solvent‐free electrolytes for lithium ion batteries

In this study, solvent‐free nanofibrous electrolytes were fabricated through an electrospinning method. Polyethylene oxide (PEO), lithium perchlorate and ethylene carbonate were used as polymer matrix, salt and plasticizer respectively in the electrolyte structures. Keggin‐type hetero polyoxometalate (Cu‐POM@Ru‐rGO, Ni‐POM@Ru‐rGO and Co‐POM@Ru‐rGO (POM, polyoxometalate; rGO, reduced graphene oxide)) nanoparticles were synthesized and inserted into the PEO‐based nanofibrous electrolytes. TEM and SEM analyses were carried out for further evaluation of the synthesized filler structures and the electrospun nanofibre morphologies. The fractions of free ions and crystalline phases of the as‐spun electrolytes were estimated by obtaining Fourier transform infrared and XRD spectra, respectively. The results showed a significant improvement in the ionic conductivity of the nanofibrous electrolytes by increasing filler concentrations. The highest ionic conductivity of 0.28 mS cm^?1 was obtained by the introduction of 0.49 wt% Co‐POM@Ru‐rGO into the electrospun electrolyte at ambient temperature. Compared with solution‐cast polymeric electrolytes, the electrospun electrolytes present superior ionic conductivity. Moreover, the cycle stability of the as‐spun electrolytes was clearly improved by the addition of fillers. Furthermore, the mechanical strength was enhanced with the insertion of 0.07 wt% fillers to the electrospun electrolytes. The results implied that the prepared nanofibres are good candidates as solvent‐free electrolytes for lithium ion batteries. © 2020 Society of Chemical Industry     

Ground bounce in digital VLSI circuits

This paper is concerned with the analysis and optimization of the ground bounce in digital CMOS circuits. First, an analytical method for calculating the ground bounce is presented. The proposed method relies on accurate models of the short-channel MOS device and the chip-package interface parasitics. Next the effect of ground bounce on the propagation delay and the optimum tapering factor of a multistage buffer is discussed and a mathematical relationship for total propagation delay in the presence of the ground bounce is obtained. Effect of an on-chip decoupling capacitor on the ground bounce waveform and circuit speed is analyzed next and a closed form expression for the peak value of the differential-mode component of the ground bounce in terms of the on-chip decoupling capacitor is provided. Finally, a design methodology for controlling the switching times of the output drivers to minimize the ground bounce is presented.     

Analysis of the PLL jitter due to power/ground and substrate noise

Phase-locked loops (PLL) in radio-frequency (RF) and mixed analog-digital integrated circuits (ICs) experience substrate coupling due to the simultaneous circuit switching and power/ground (P/G) noise which translate to a timing jitter. In this paper. an analysis of the PLL timing jitter due to substrate noise resulting from P/G noise and large-signal switching is presented. A general comprehensive stochastic model of the substrate and P/G noise sources in very large-scale integration (VLSI) circuits is proposed. This is followed by calculation of the phase noise of the constituent voltage-controlled oscillator (VCO) in terms of the statistical properties of substrate and P/G noise. The PLL timing jitter is then predicted in response to the VCO phase noise. Our mathematical method is utilized to study the jitter-induced P/G noise in a CMOS PLL, which is designed and simulated in a 0.25-/spl mu/m standard CMOS process. A comparison between the results obtained by our mathematical model and those obtained by HSPICE simulation prove the accuracy of the predicted model.     

Numerical study of the variable-order fractional version of the nonlinear fourth-order 2D diffusion-wave equation via 2D Chebyshev wavelets

Engineering with Computers - In this article, the 2D Chebyshev wavelets (CWs) are used for designing a proper procedure to solve the variable-order (VO) fractional version of the nonlinear...     

Chebyshev polynomials for the numerical solution of fractal–fractional model of nonlinear Ginzburg–Landau equation

Engineering with Computers - This paper introduces a new version for the nonlinear Ginzburg–Landau equation derived from fractal–fractional derivatives and proposes a computational...     

Electron Microscopy Imaging Applications of Room Temperature Ionic Liquids in the Biological Field: A Review

For biological imaging using electron microscopy (EM), the use of room-temperature ionic liquids (RTILs) has been proposed as an alternative to traditional lengthy preparation methods. With their low vapor pressures and conductivity, RTILs can be applied onto hard-to-image soft and/or wet samples without dehydration – allowing for a more representative, hydrated state of material and opening the possibility for visualization of in situ physiological processes using conventional EM systems. However, RTILs have yet to be utilized to their full potential by microscopists and microbiologists alike. To this end, this review aims to provide a comprehensive summary of biological applications of RTILs for EM to bridge the RTIL, in situ microscopy, and biological communities. We outline future research avenues for the use of RTILs for the EM observation of biological samples, notably i) RTIL selection and optimization, ii) applications for live cell processes and iii) electron beam and ionic liquid interaction studies.     

Robust and stable flow shop scheduling with unexpected arrivals of new jobs and uncertain processing times

In real scheduling problems, some disruptions and unexpected events may occur. These disruptions cause the initial schedule to quickly become infeasible and non-optimal. In this situation, an appropriate rescheduling method should be used. In this paper, a new approach has been proposed to achieve stable and robust schedule despite uncertain processing times and unexpected arrivals of new jobs. This approach is a proactive–reactive method which uses a two-step procedure. In the first step an initial robust solution is produced proactively against uncertain processing times using robust optimization approach. This initial robust solution is more insensitive against the fluctuations of processing times in future. In the next step, when an unexpected disruption occurs, an appropriate reactive method is adopted to deal with this unexpected event. In fact, in the second step, the reactive approach determines the best modified sequence after any unexpected disruption based on the classical objective and performance measures. The robustness measure is implemented in the reactive approach to increase the performance of the real schedule after disruption. Computational results indicate that this method produces better solutions in comparison with four classical heuristic approaches according to effectiveness and performance of solutions.     

Feedback control for multi-resource usage of virtualised database server

Virtualisation and cloud computing have recently received significant attention. Resource allocation and control of multiple resource usages among virtual machines in virtualised data centres remains an open problem. Therefore, in this paper, our focus is to control CPU (central processing unit) usage and memory consumption of a virtual database machine in a data centre under a time-varying heavy workload. In addition to existing work, we attempt to control multiple outputs, such as the CPU usage and memory consumption of a virtualised database server (DBVM), via changing multiple server parameters, such as the CPU allocation and memory allocation, in real time. We indicated that a virtualised database server might be modelled as a linear time-unvarying system. We obtained and compared both MIMO (multi input–multi output) and multiple SISO (single input–single output) models of that system. We designed multiple SISO feedback controllers to achieve desired CPU usages and memory consumptions under workload.     

Some results on disturbance attenuation for Hamiltonian systems via direct discrete‐time design

The disturbance attenuation and robust disturbance attenuation problems for Hamiltonian systems in the discrete‐time setting are considered and some new results are presented. The new results are derived utilizing the recently presented dissipativity equality obtained by adding the dissipation rate function to the classical dissipativity inequality. A selection of the dissipation rate function yields new results. These results include a condition on the dissipation structure of the system to achieve the desired disturbance attenuation level and gives direct construction of optimal control laws for any desired disturbance attenuation level. The results remove the need to solve Hamilton–Jacobi–Isaacs inequalities. Copyright © 2014 John Wiley & Sons, Ltd.     

The use and acceptance of new media entertainment technology by elderly users: development of an expanded technology acceptance model

Research on elderly people's ICT acceptance and use often relies on the technology acceptance model (TAM) framework, but has been mostly limited to task-oriented uses. This article expands approaches in technology acceptance and use by developing a model to explain entertainment-related uses of new media technology by elderly people. On a theoretical level, we expand the TAM perspective by adding concepts that act as barriers and/or facilitators of technology acceptance, namely technophobia, self-efficacy and previous experience and expertise with technology. We develop an expanded TAM by testing the role of these concepts in two studies on entertainment media technology. In Study 1, we investigate behavioural intention to use 3D cinema among N?=?125 German elderly media users (Age 50+). In Study 2, we focus the actual use of a computer game simulation by N?=?115 German and US elderly media users (Age 50+). Findings in both studies point towards the central role of perceived usefulness, here modelled as enjoyment, as the reason for elderly people's use and acceptance of entertainment media technology. Perceived ease of use is seen as a precondition for enjoyment, particularly for interactive media.