J. António¹ , A. Tadeu¹, L. Godinho

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.3, pp. 157-162, 2007, DOI:10.3970/icces.2007.003.157

Abstract A frequency dependent formulation based on the Method of Fundamental Solutions (MFS) is used to simulate the sound wave propagation in a 3D acoustic space. This solution is approximated by a linear combination of fundamental solutions generated by virtual sources placed outside the domain in order to avoid singularities. The coating materials can be assumed to be absorbent. This is achieved in the model prescribing the impedance that is defined as a function of the absorption coefficient. The model is first verified against analytical solutions, provided by the image source technique for a parallelepiped room bounded by rigid walls. The… More >

C. M. Meenakshi, A. Krishnamoorthy^*

Journal of Renewable Materials, Vol.7, No.2, pp. 153-169, 2019, DOI:10.32604/jrm.2019.00046

Abstract Natural fiber-reinforced hybrid composites can be a better replacement for plastic composites since these plastic composites pose a serious threat to the environment. The aim of this study is to analyze the effect of surface modification of the natural fibers on the mechanical, thermal, hygrothermal, and water absorption behaviors of flax, sisal, and glass fiber-reinforced epoxy hybrid composites. The mechanical properties of alkaline treated sisal and flax fibers were found to increase considerably.Tensile, flexural and impact strength of glass/flax-fiber-reinforced hybrid samples improved by 58%, 36%, and 51%, respectively, after surface alkaline treatment. In addition, the hygrothermal analysis and water absorption… More >

Min Fan^1,2,3*, Qiaoling Hu⁴

Journal of Renewable Materials, Vol.6, No.5, pp. 457-463, 2018, DOI:10.7569/JRM.2017.634178

Abstract The absorption behavior of chitosan in alkaline solution by freeze-blasting was studied. The influence of alkaline type, concentration, and small molecules was investigated, as well as the different roles of LiOH and NaOH in the absorption. Chitosan reached its maximum absorption rate when LiOH concentration was 4.8 wt% and NaOH 4.0 wt%, respectively. Chitosan showed better absorption capacity in LiOH solution. Urea could improve the absorption when its concentration was more than or equal to 4.0 wt%, and the improvement was greater in NaOH solution. Thiourea showed no obvious effect in LiOH solution, but showed an effect when NaOH concentration… More >

N. A. Sri Aprilia¹, M. S. Nurul Atiqah², Zhari Ismail³, C. Y. Loo², Chaturbhuj K. Saurabh², Rudi Dungani⁴, Abdul Khalil H.P.S^2*

Journal of Renewable Materials, Vol.5, No.5, pp. 380-387, 2017, DOI:10.7569/JRM.2017.634130

Abstract Due to environmental concerns, green composites have become a highly researched material. In the present study, kenaf fiber was used as reinforcement in epoxy-based composite with weight fraction ranges from 0, 5, 10, and 15% (w/w of resin). The ratio of epoxy to hardener was 65:32.5. Prior to incorporation, kenaf bast fiber underwent Soda-AQ pulping followed by total chlorine-free bleaching (OAZP sequence). The obtained pulp was then subjected to supercritical carbon dioxide extraction (SCE) treatment. It was observed that epoxy composite with 10% of fiber loading demonstrated the highest mechanical properties with a tensile strength of 64 MPa, tensile modulus… More >

Umadevi. B, Dinesh P.A., Indira R., Vinay. C.V

Molecular & Cellular Biomechanics, Vol.11, No.2, pp. 101-111, 2014, DOI:10.3970/mcb.2014.011.101

Abstract The mass transfer in an eccentric annular region through diffusion by taking blood as a Newtonian fluid with the investigation of oxygen transfer and drug transport to the tissue cells in an eccentric catheterized artery is studied. The region bounded by eccentric circles in x-y plane is mapped conformally to concentric circles in \(\xi -\eta\) plane using a conformal mapping \(z = \lambda /1 - \zeta\). The resulting governing equations are analytically solved by using transformation for the concentration. Numerical computations are carried out to understand the simultaneous~effects of absorption parameter and eccentricity on the flow. ~The observation through the… More >

Anusha Eldo¹, Balamati Choudhury²

CMC-Computers, Materials & Continua, Vol.52, No.3, pp. 143-157, 2016, DOI:10.3970/cmc.2016.052.142

Abstract The advances in metamaterial science and technology have raised the expectations of camouflage or stealth researchers to one order higher in terms of absorption characteristics. As metamaterial inspired radar absorbing structures are proving themselves as a good candidate with near unity absorption, feasibility towards hardware realization is necessary. Hence an extensive literature survey of metamaterial inspired radar absorbing structure has been carried out and reported in this paper along with the challenges and material issues. The various types of metamaterial structures that can be used as absorber have been provided along with simulation figures. To make the review more useful,… More >

Youssef F. Rashed¹

CMC-Computers, Materials & Continua, Vol.1, No.4, pp. 319-326, 2004, DOI:10.3970/cmc.2004.001.319

Abstract The present paper develops a new technique for treatment of self-weight for building slabs in the boundary element method (BEM). Due to the use of BEM in the analysis, all defined variables are presented on the slab boundary (mesh is defined only along the slab boundary). Self-weight, however, is usually defined over slab domain, hence domain discretisation is required, which spoils the main advantage of the BEM. In this paper a new method is presented to transform self-weight domain integrals to the boundary for such slabs. The proposed method is based on using the so-called Green's first identity. All new… More >

Ehsan Hedayati¹, Mohammad Vahedi²

CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.3, pp. 295-323, 2017, DOI:10.3970/cmes.2017.113.307

Abstract Radius of ceramic cone can largely contribute into final solution of analytic models of penetration into ceramic/metal targets. In the present research, a modified model based on radius of ceramic cone was presented for ceramic/aluminum targets. In order to investigate and evaluate accuracy of the presented analytic model, obtained results were compared against the results of the Florence’s analytic model and also against numerical modeling results. The phenomenon of impact onto ceramic/aluminum composites were modeled using smoothed particle hydrodynamics (SPH) implemented utilizing ABAQUS Software. Results indicated that, with increasing initial velocity and ceramic thickness and decreasing support layer thickness, the… More >

Liming Yang^1,2, Junjian Bai¹, Qun Sun³

CMES-Computer Modeling in Engineering & Sciences, Vol.108, No.1, pp. 49-65, 2015, DOI:10.3970/cmes.2015.108.049

Abstract Extreme learning machine (ELM) has demonstrated great potential in machine learning and data mining fields owing to its simplicity, rapidity and good generalization performance. In this work, a general framework for ELM regression is first investigated based on least absolute deviation (LAD) estimation (called LADELM), and then we develop two regularized LADELM formulations with the l₂-norm and l₁-norm regularization, respectively. Moreover, the proposed models are posed as simple linear programming or quadratic programming problems. Furthermore, the proposed models are used directly to analyze the hard rate of licorice seeds using near-infrared spectroscopy data. Experimental results on eight different spectral regions… More >

Chengxi Li¹

CMES-Computer Modeling in Engineering & Sciences, Vol.107, No.2, pp. 125-153, 2015, DOI:10.3970/cmes.2015.107.125

Abstract Applying an efficient numerical wave absorption method is very important for realization of an open sea condition especially for long time numerical fluid structure interaction simulation. This paper proposed a hybrid numerical wave absorption method for the fully nonlinear fluid structure simulation. A numerical code “QBEM” which is based on the quadratic boundary element method is applied to evaluate the efficiency of the wave absorption methods and damping schemes by checking the energy conservation and wave elevation in the computational domain. Specifically, we conduct a 3D numerical wave tank experiment to find the bestperforming damping scheme inside the damping zone… More >