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Advanced Design, Fabrication, and Applications of 3D-Printable Piezoelectric Nanogenerators
M. A. Parvez Mahmud,Partho Adhikary,Ali Zolfagharian,Scott Adams,Akif Kaynak,Abbas Z. Kouzani 대한금속·재료학회 2022 ELECTRONIC MATERIALS LETTERS Vol.18 No.2
Piezoelectric nanogenerator (PENG) is a leading-edge mechanical energy harvesting device used in portable power supplyand self-powered sensor systems. Advanced 3D printers have been recently used to create 3D printed (3DP) PENGs. This hasfacilitated the rapid fabrication of PENGs and their integration into wearable electronics, biomedical systems, and internetof things devices. However, researchers face several critical challenges in developing robust 3DP-PENGs that can produceadequate electrical energy for self-powered systems. Therefore, this review on 3DP-PENGs is conducted to highlight theirrecent developments and challenges. This paper presents the latest 3D-printed piezoelectric nanogenerators in terms of theirmaterials selection and functionalization, design and architecture formation, and applications including pressure sensors,fl ow sensors, microphones, and implants. Finally, crucial challenges and optimization strategies that considerably impactthe output performance of 3DP-PENGs, along with a roadmap for their future enhancement are given. It is envisioned thatthis work will help reduce the gap between 3D printing and PENG technologies and accelerate the research and developmentof 3DP-PENGs.
Mostafizur Rahaman,Ibnelwaleed Ali Hussein,Ali Aldalbahi,Anwar Parvez,Joao B. P. Soares 한국고분자학회 2018 Macromolecular Research Vol.26 No.4
In this article, metallocene catalyzed polyethylene homopolymer and ethylene 1,7-octadiene copolymers were synthesized and the produced polymers were characterized. The results show that these polymers were high density polyethylene. The effect of comonomer 1,7-octadiene on thermal, mechanical, and rheological properties of the polymers was investigated. The molecular weight, melting temperature (T m), d-spacing, crystallite size, and % crystallinity (% X c) decrease with the increase in comonomer content. Polyethylene homopolymer and copolymer exhibit cold drawing processes. The tensile stress-strain plots show multiple necks. A reduction in tensile modulus, strength, and strain at break is seen for copolymers compared to homopolymer. The effect of comonomer content on dynamic and extensional rheology of the polymers was also studied. In addition, Direct Current conductivity and dielectric property of the polymers were also reported. The results were interpreted in terms of mainly polymer type, molecular weight, and crystallinity.
Cospectral and hyper-energetic self complementary comparability graphs
( Merajuddin ),( S. A. K. Kirmani ),( Parvez Ali ),( S. Pirzada ) 한국산업응용수학회(구 한국산업정보응용수학회) 2007 한국산업정보응용수학회 Vol.11 No.3
A graph G is self-complementary (sc) if it is isomorphic to its complement. G is perfect if for all induced subgraphs H of G, the chromatic number of H (denoted X(H)) equals the number of vertices in the largest clique in H (denoted w(H)). An sc graph which is also perfect is known as sc perfect graph. A comparability graph is an undirected graph if it can be oriented into transitive directed graph. An sc comparability (scc) is clearly a subclass of sc perfect graph. In this paper we show that no two non-isomorphic scc graphs with n vertices each, (n < 13) have same spectrum, and that the smallest positive integer for which there exists hyper-energetic scc graph is 13.
Cospectral and hyper-energetic self complementary comparability graphs
Merajuddin,S. A. K. Kirmani,Parvez Ali,S. Pirzada 한국산업응용수학회 2007 Journal of the Korean Society for Industrial and A Vol.11 No.3
A graph G is self-complementary (sc) if it is isomorphic to its complement. G is perfect if for all induced subgraphs H of G, the chromatic number of H (denoted X(H)) equals the number of vertices in the largest clique in H (denoted w(H)). An sc graph which is also perfect is known as sc perfect graph. A comparability graph is an undirected graph if it can be oriented into transitive directed graph. An sc comparability (sec) is clearly a subclass of sc perfect graph. In this paper we show that no two non-isomorphic sec graphs with n vertices each, (n < 13) have same spectrum, and that the smallest positive integer for which there exists hyper-energetic sec graph is 13.