Zhimei Li¹, Kuan Tian², Keping Wang², Zhengyi Li², Haoli Qin^1,*, Hu Li^2,*

Journal of Renewable Materials, Vol.11, No.11, pp. 3847-3865, 2023, DOI:10.32604/jrm.2023.030122

Abstract Sustainable acquisition of bioactive compounds from biomass-based platform molecules is a green alternative for existing CO₂-emitting fossil-fuel technologies. Herein, a core–shell magnetic biocarbon catalyst functionalized with sulfonic acid (Fe₃O₄@SiO₂@chitosan-SO₃H, MBC-SO₃H) was prepared to be efficient for the synthesis of various N-substituted pyrroles (up to 99% yield) from bio-based hexanedione and amines under mild conditions. The abundance of Brønsted acid sites in the MBC-SO₃H ensured smooth condensation of 2,5-hexanedione with a variety of amines to produce N-substituted pyrroles. The reaction was illustrated to follow the conventional PallKnorr coupling pathway, which includes three cascade reaction steps: amination, loop closure and dehydration. The… More > Graphic Abstract

Kenneth R. Podolak^*, Vihan A.W. Wickramasinghe, Gareth A. Mansfield, Alex M. Tuller

Sound & Vibration, Vol.55, No.3, pp. 235-240, 2021, DOI:10.32604/sv.2021.015008

Abstract Ernst Chladni is called the father of acoustics for his work, which includes investigating patterns formed by vibrating plates. Understanding these patterns helps research involving standing waves and other harmonic behaviors, including studies of single electron orbits in atoms. Our experiment vibrates circular plates which result in well-known patterns. Alternatively to traditional experiments that used sand or salt, we use magnetic materials, namely iron filings and nickel powder. We then manipulate the patterns by applying a localized external magnetic field to one of the rings that moves a segment of the magnetic material in that ring to the next inner… More >

V.I. Alshits^1,2, R.K. Kotowski^1,3, P. Tronczyk¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.4, pp. 207-214, 2008, DOI:10.3970/icces.2008.006.207

Abstract The magnetoplastic effect manifests itself in a transformation of the structure of the impurity pinning centers in crystals exposed to an external magnetic field which modifies their mechanical properties. As a result, an ordinary nonmagnetic crystal becomes a smart material whose physical properties may be controlled by means of the external magnetic treatment. The basic features of this phenomenon and its established physical mechanisms are discussed. A series of results of experimental studies and computer simulations of the magnetoplastic effect are presented. More >

John L. Volakis¹, Kubilay Sertel¹, Erik Jørgensen², Rick W. Kindt¹

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.5, pp. 463-476, 2004, DOI:10.3970/cmes.2004.005.463

Abstract In this paper we address several topics relating to the development and implementation of volume integral and hybrid finite element methods for electromagnetic modeling. Comparisons of volume integral equation formulations with the finite element-boundary integral method are given in terms of accuracy and computing resources. We also discuss preconditioning and parallelization of the multilevel fast multipole method, and propose higher-order basis functions for curvilinear quadrilaterals and volumetric basis functions for curvilinear hexahedra. The latter have the desirable property of vanishing divergence within the element but non-zero curl. In addition, a new domain decomposition is introduced for solving array problems involving… More >