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Asif Khan

Bio: Asif Khan is an academic researcher from Dongguk University. The author has contributed to research in topics: Smart grid & Composite laminates. The author has an hindex of 17, co-authored 70 publications receiving 989 citations. Previous affiliations of Asif Khan include University of Peshawar & COMSATS Institute of Information Technology.


Papers
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Journal ArticleDOI
17 Apr 2017-Energies
TL;DR: In this paper, the authors proposed an optimized home energy management system (OHEMS) that not only facilitates the integration of renewable energy source (RES) and energy storage system (ESS) but also incorporates the residential sector into DSM activities.
Abstract: Traditional power grid and its demand-side management (DSM) techniques are centralized and mainly focus on industrial consumers. The ignorance of residential and commercial sectors in DSM activities degrades the overall performance of a conventional grid. Therefore, the concept of DSM and demand response (DR) via residential sector makes the smart grid (SG) superior over the traditional grid. In this context, this paper proposes an optimized home energy management system (OHEMS) that not only facilitates the integration of renewable energy source (RES) and energy storage system (ESS) but also incorporates the residential sector into DSM activities. The proposed OHEMS minimizes the electricity bill by scheduling the household appliances and ESS in response to the dynamic pricing of electricity market. First, the constrained optimization problem is mathematically formulated by using multiple knapsack problems, and then solved by using the heuristic algorithms; genetic algorithm (GA), binary particle swarm optimization (BPSO), wind driven optimization (WDO), bacterial foraging optimization (BFO) and hybrid GA-PSO (HGPO) algorithms. The performance of the proposed scheme and heuristic algorithms is evaluated via MATLAB simulations. Results illustrate that the integration of RES and ESS reduces the electricity bill and peak-to-average ratio (PAR) by 19.94% and 21.55% respectively. Moreover, the HGPO algorithm based home energy management system outperforms the other heuristic algorithms, and further reduces the bill by 25.12% and PAR by 24.88%.

197 citations

Journal ArticleDOI
TL;DR: In this paper, a convolutional neural network (CNN) based approach was proposed for the classification and prediction of various types of in-plane and through-the-thickness delamination in smart composite laminates using low-frequency structural vibration outputs.
Abstract: This paper proposes a Convolutional Neural Network (CNN) based approach for the classification and prediction of various types of in-plane and through-the-thickness delamination in smart composite laminates using low-frequency structural vibration outputs. An electromechanically coupled mathematical model is developed for the healthy and delaminated smart composite laminates, and their structural vibration responses are obtained in the time domain. Short Time Fourier Transform (STFT) is employed to transform the transient responses into two-dimensional spectral frame representation. A convolutional neural network is incorporated to distinguish between the damaged and undamaged states, as well as various types of damage of the laminated composites, by automatically extracting discriminative features from the vibration-based spectrograms. The CNN showed a classification accuracy of 90.1% on one healthy and 12 delaminated cases. The study of the confusion matrix of CNN provided further insights into the physics of the problem. The predictive performance of a pre-trained CNN classifier was also evaluated on unseen cases of delamination, and physically consistent results were obtained.

135 citations

Journal ArticleDOI
Salman Khalid1, Izaz Raouf1, Asif Khan1, Nayeon Kim1, Heung Soo Kim1 
TL;DR: This review article reports on the piezoelectric, electromagnetic, and triboelectrics energy harvesting technologies that can effectively scavenge biomechanical energy from human motion such as, walking, stretching, and human limb movement, as well as from small displacements inside the human body.
Abstract: Recently, energy harvesting from human motion has attracted substantial research into its ability to replace conventional batteries for smart electronics. Human motion exhibits excellent potential to provide sustainable and clean energy for powering low-powered electronics, such as portable instruments and wearable devices. This review article reports on the piezoelectric, electromagnetic, and triboelectric energy harvesting technologies that can effectively scavenge biomechanical energy from human motion such as, walking, stretching, and human limb movement, as well as from small displacements (e.g., heartbeat, respiration, and muscle movement) inside the human body. Furthermore, various recent designs and configurations of human motion energy harvesters are presented according to their working mechanisms, device compositions, and performances. In order to provide insight into future research prospects, the paper also discusses the limitations, issues, and challenges of piezoelectric, electromagnetic, and triboelectric energy harvesting technologies for the development of smart electronics.

120 citations

Journal ArticleDOI
TL;DR: Wang et al. as mentioned in this paper investigated P efficiency, soil P availability and P downward movement in the deep profile of a loess soil in China, and they concluded that P supply in excess of the crop's requirement resulted in not only low P efficiency and massive accumulation of P in the topsoil but also leaching out of root zone under both irrigated and rain-fed conditions in the Loess soil.

81 citations


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2,415 citations

01 Jan 1987
TL;DR: Eisma et al. as mentioned in this paper showed that the CEC can vary over 2 orders of magnitude for various types of, minerals and can vary one order of magnitude within one soil type.
Abstract: Positive ions that are available in soils absorb on grain surfaces. The total sum of cations that can be absorbed bij a soil/sediment at a certain PH is defined by the cation-exchange capacity (CEC, in meq g-1: mol equivalents per gram). The uptake of cations is an important parameter in agriculture and the larger the CEC, the more cations can be absorbed to the soil. The CEC depends highly on the pH of soil and sediments, where the CEC decreases with decreasing PH (increasing acidity). The exchange of ions on sediments occurs commonly fast on geological time scales, but the kinetics of adsorption in natural environments is still poorly understood. The strength of the bonding between the cations and the sediments varies from weak Van der Waals bondings (physical adsorption) to strong chemical bonds. The CEC is widely used for agricultural assessment because it is a measure of general soil fertility as well as an indicator of structural stability because CED is capabel of enhancing development of shrinkage cracks. The list below shows the CEC for different types of minerals. The data indicate that the CEC can vary over 2 orders of magnitude for various types of , minerals and can vary one order of magnitude within one soil type. Cation exchange capacity for different types of sediment (Eisma, 1992; Locher and de Bakker, 1990):

1,169 citations

Journal ArticleDOI
18 Apr 2018-Joule
TL;DR: A comprehensive review of piezoelectric energy-harvesting techniques developed in the last decade is presented, identifying four promising applications: shoes, pacemakers, tire pressure monitoring systems, and bridge and building monitoring.

720 citations

Journal ArticleDOI
17 Jul 2017-ACS Nano
TL;DR: The study reveals the potential for utilizing piezoelectric 2D materials and their van der Waals multilayer structures in device applications.
Abstract: Piezoelectricity in 2D van der Waals materials has received considerable interest because of potential applications in nanoscale energy harvesting, sensors, and actuators. However, in all the systems studied to date, strain and electric polarization are confined to the basal plane, limiting the operation of piezoelectric devices. In this paper, based on ab initio calculations, we report a 2D materials system, namely, the recently synthesized Janus MXY (M = Mo or W, X/Y = S, Se, or Te) monolayer and multilayer structures, with large out-of-plane piezoelectric polarization. For MXY monolayers, both strong in-plane and much weaker out-of-plane piezoelectric polarizations can be induced by a uniaxial strain in the basal plane. For multilayer MXY, we obtain a very strong out-of-plane piezoelectric polarization when strained transverse to the basal plane, regardless of the stacking sequence. The out-of-plane piezoelectric coefficient d33 is found to be strongest in multilayer MoSTe (5.7–13.5 pm/V depending on t...

522 citations