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Coconut shell waste as an alternative lightweight aggregate in concrete- A review
Muhammad ,Aslam,Waqas, Aziz,M. Jahanzaib, Khalil,M. Jahanzaib, Ali,Muhammad, Raheel,Aayzaz, Ahmed,Muhammad Fahad, Ejaz Techno-Press 2022 Advances in materials research Vol.11 No.4
This review article highlights the physical, mechanical, and chemical properties of coconut shells, and the fresh and hardened properties of the coconut shell concrete are summarized and were compared with other types of aggregates. Furthermore, the structural behavior in terms of flexural, shear, and torsion was also highlighted, with other properties including shrinkage, elastic modulus, and permeability of the coconut shell concrete. Based on the reviewed literature, concrete containing coconut shell as coarse aggregate with normal sand as fine showed the 28-day compressive strength between 2 and 36 MPa with the dried density range of 1865 to 2300 kg/m<sup>3</sup>. Coconut shell concretes showed a 28-day modulus of rupture and splitting tensile strength values in the ranges of 2.59 to 8.45 MPa and 0.8 to 3.70 MPa, respectively, and these values were in the range of 5-20% of the compressive strength. The flexural behavior of CSC was found similar to other types of lightweight concrete. There were no horizontal cracks on beams which indicate no bond failure. Whereas, the diagonal shear failure was prominent in beams with no shear reinforcements while flexural failure mode was seen in beams having shear reinforcement. Under torsion, CSC beams behave like conventional concrete. Finally, future recommendations are also suggested in this study to investigate the innovative lightweight aggregate concrete based on the environmental and financial design factors.
Antioxidant Activity with Flavonoidal Constituents from Aerva persica
Ejaz Ahmed,Muhammad Imran,Abdul Malik,Muhammad Ashraf 대한약학회 2006 Archives of Pharmacal Research Vol.29 No.5
A new flavanone Persinol (1) and the new flavanone glucosides persinosides A (2) and B (3), along with known flavonoids (4 and 5) have been isolated from the ethyl acetate soluble fraction of the whole plants of Aerva persica. Their structures were elucidated on the basis of extensive analysis of nuclear magnetic resonance (1D & 2D-NMR) spectral data. All of them showed profound antioxidative activities by DPPH and cytochrome-c-reduction assays using the HL-60 cell culture system.
Muhammad Ismail,Shazia Jabeen,Tahira Akber,Ijaz Talib,Fayyaz Hussain,Anwar Manzoor Rana,Muhammad Hussain,Khalid Mahmood,Ejaz Ahmed,Dinghua Bao 한국물리학회 2018 Current Applied Physics Vol.18 No.8
Effect of oxygen annealing on bipolar resistive switching (BRS) properties of TiN/ZnO/CeO2-x/Pt devices was investigated. Bilayer ZnO/CeO2-x thin films were fabricated by rf-magnetron sputtering. It was observed that the improvement in cycle-to-cycle endurance degradation and uniformity of the bilayer ZnO/CeO2-x thin film is optimum at 400 °C annealing temperature due to decrease in oxygen vacancies during annealing, as confirmed by x-ray photoelectron spectroscopy. The BRS could be caused by the formation of interfacial TiON layer, which is most likely to be accountable for creating an adequate quantity of oxygen vacancies necessary for the formation and rupture of conductive filaments. Smaller Gibbs free energy of the formation of interfacial TiON (−611 kJmol−1) layer as compared to bilayer film ZnO (−650 kJmol−1) and CeO2 (−1024 kJmol−1) results in an easier re-oxidation of the filaments through the oxygen exchange with TiN top electrode. The analysis of current– voltage characteristics shows that the charge transport mechanism is Schottky emission. Moreover, the temperature dependence of high resistance state (HRS) and low resistance state (LRS) revealed the physical origin of the RS mechanism, which entails the oxygen vacancies for the formation and rupture of conducting paths.
ROBUST DIFFERENTIAL STEERING CONTROL SYSTEM FOR AN INDEPENDENT FOUR WHEEL DRIVE ELECTRIC VEHICLE
Muhammad Arshad Khan,Muhammad Faisal Aftab,Ejaz Ahmed,윤일중 한국자동차공학회 2019 International journal of automotive technology Vol.20 No.1
This research investigates a robust differential steering control system (DSCS) for an independent four wheel drive electric vehicle (EV). The DSCS will maneuver the independently actuated (IA) four wheel drive EV without the help of any conventional steering mechanism (CSM) via the input torque of the four wheels. The differential angular rotation speed between left and right wheels is used to generate the CSM effects. The DSCS is designed using the linear model of the vehicle with linear tire dynamics and is tested in simulations using a nonlinear vehicle model with nonlinear tire dynamics. The proposed DSCS is a combination of forward speed and yaw rate controllers, designed using the robust H∞ control methodology. The effectiveness of the proposed robust controller is analyzed by comparing the performance of the all-wheel drive (AWD), the rear wheel drive (RWD), and the front wheel drive (FWD) vehicles during simulations. The simulations results indicates that the proposed system can successfully maneuver the vehicle under different driving conditions by tracking the desired parameters without the use of any CSM.
Graph Compression by Identifying Recurring Subgraphs
무하메드이자즈아메드 ( Muhammad Ejaz Ahmed ),이정훈 ( Jeonghoon Lee ),나인혁 ( Inhyuk Na ),손샘 ( Sam Son ),한욱신 ( Wook-shin Han ) 한국정보처리학회 2017 한국정보처리학회 학술대회논문집 Vol.24 No.1
Current graph mining algorithms suffers from performance issues when querying patterns are in increasingly massive network graphs. However, from our observation most data graphs inherently contains recurring se mantic subgraphs/substructures. Most graph mining algorithms treat them as independent subgraphs and perform computations on them redundantly, which result in performance degradation when processing massive graphs. In this paper, we propose an algorithm which exploits these inherent recurring subgraphs/substructures to reduce graph sizes so that redundant computations performed by the traditional graph mining algorithms are reduced. Experimental results show that our graph compression approach achieve up to 69% reduction in graph sizes over the real datasets. Moreover, required time to construct the compressed graphs is also reasonably reduced.
Traffic-Aware Optimal Spectral Access in Wireless Powered Cognitive Radio Networks
Ahmed, Muhammad Ejaz,Kim, Dong In,Choi, Kae Won IEEE Computer Society 2018 IEEE TRANSACTIONS ON MOBILE COMPUTING Vol.17 No.3
<P>Traffic patterns associated with different primary users (PUs) might provide different spectral access and energy harvesting opportunities to secondary users (SUs) in wireless powered cognitive radio networks (WP-CRNs). Since the traffic applications have their own distinctive patterns, spectral access and energy harvesting opportunities are also expected to be distinctive. In this paper, we propose a novel approach to identify the PU traffic patterns and estimate the energy harvested from each traffic pattern so that SU can maximize its capacity accordingly. More specifically, we propose a theoretical framework based on a variational inference algorithm to cluster various traffic patterns and design a threshold-based SU transmission strategy by taking into account the spectral access and energy harvesting opportunities for each traffic pattern, so as to optimize SU transmission. Through simulations, we demonstrate the effectiveness of the proposed scheme in terms of throughput gains and show the transmission thresholds under various traffic applications (patterns). Further, we illustrate the effects of different collision costs on throughput for different traffic applications using real wireless traces.</P>
Antioxidant Activity with Flavonoidal Constituents from Aerva persica
Ahmed Ejaz,Imran Muhammad,Malik Abdul,Ashraf Muhammad The Pharmaceutical Society of Korea 2006 Archives of Pharmacal Research Vol.29 No.5
A new flavanone Persinol (1) and the new flavanone glucosides persinosides A (2) and B (3), along with known flavonoids (4 and 5) have been isolated from the ethyl acetate soluble fraction of the whole plants of Aerva persica. Their structures were elucidated on the basis of extensive analysis of nuclear magnetic resonance (1D & 2D-NMR) spectral data. All of them showed profound antioxidative activities by DPPH and cytochrome-c-reduction assays using the HL-60 cell culture system.