Dragomir Vassilev^1*, Nadezhda Petkova², Milena Koleva¹, Panteley Denev²

Journal of Renewable Materials, Vol.4, No.1, pp. 24-30, 2016, DOI:10.7569/JRM.2015.634125

Abstract This article presents the results obtained by the ultrasound-assisted synthesis of sucrose and fructooligosaccharides (FOS) esters with fatty acids (palmitic and 10-undecylenic), the identifi cation of the products and the study of their possible application as plasticizers in plastics processing. Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (¹H and ¹³C NMR) spectroscopy were used to identify the synthesized carbohydrate esters. The plasticizing effect of the sucrose palmitate applied in polyvinyl chloride (PVC) was evaluated by the glass transition temperatures; the decrease of the T_g with the increase of the ester content could be accepted as confi rmation of… More >

Q Wang^*, YP Zheng^∗,†, HJ Niu^∗,‡

Molecular & Cellular Biomechanics, Vol.7, No.1, pp. 45-58, 2010, DOI:10.3970/mcb.2010.007.045

Abstract This study aims to obtain osmosis-induced swelling strains of normal and proteoglycan (PG) depleted articular cartilage using an ultrasound system and to investigate the changes in its mechanical properties due to the PG depletion using a layered triphasic model. The swelling strains of 20 cylindrical cartilage-bone samples collected from different bovine patellae were induced by decreasing the concentration of bath saline and monitored by the ultrasound system. The samples were subsequently digested by a trypsin solution for approximately 20 min to deplete proteoglycans, and the swelling behaviors of the digested samples were measured again. The bi-layered triphasic model proposed in… More >

Lin Zhou^1,*, Kangyu Ma¹, Lijie Wang¹, Ying Chen^1,2, Yibin Tang³

CMC-Computers, Materials & Continua, Vol.60, No.2, pp. 545-557, 2019, DOI:10.32604/cmc.2019.05969

Abstract Binaural sound source localization (BSSL) in low signal-to-noise ratio (SNR) and high reverberation environment is still a challenging task. In this paper, a novel BSSL algorithm is proposed by introducing convolutional neural network (CNN). The proposed algorithm first extracts the spatial feature of each sub-band from binaural sound signal, and then combines the features of all sub-bands within one frame to assemble a two-dimensional feature matrix as a grey image. To fully exploit the advantage of the CNN in extracting high-level features from the grey image, the spatial feature matrix of each frame is used as input to train the… More >

Ranu Gupta^1,3,*, Rahul Pachauri^2,3, Ashutosh Singh^1,4

CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.1, pp. 19-32, 2018, DOI:10.3970/cmes.2018.114.019

Abstract This article presents an improved method of despeckling the ultrasound medical images. In this paper a modified local statistics mean variance filter method has been proposed. In the proposed method, more consideration is given to local statistics since local statistical features are more important rather than global features.Various parameters like mean square error, peak signal to noise ratio, quality index, and structural similarity index measure are calculated to analyze the quality of the despeckled image. More >

M. D. C. Magalhaes^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.105, No.6, pp. 441-465, 2015, DOI:10.3970/cmes.2015.105.441

Abstract The main goal of this study is to present an alternative and more efficient algorithm for a three-dimensional Component Mode Synthesis model to be used on sound transmission problems. The influence of fluid-structure interaction on airborne sound transmission problems is analysed using this model, which is based on simple volume geometries. In principle, the same procedure can also be applied when the component modes are obtained from alternative numerical techniques. The modal behaviour of acoustic volumes and a partition is implemented in two steps. The novelty of this alternative model is that the structural modes are incorporated on the acoustic… More >

Max de Castro Magalhaes¹

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.4, pp. 263-281, 2012, DOI:10.3970/cmes.2012.089.263

Abstract The main objective is to develop a 'hybrid' numerical method for predicting sound power radiated from honey-comb panels and analyze the sensitivity and variability of it to different boundary conditions. The honey-comb panels are mainly used on the aerospace, mechanical and civil engineering design. The method used herein is a combination of the Finite Element Method and the Jinc Function Approach. The original contribution of this paper is therefore to show the sensitivity of sound power radiated from a honey-comb panel using a 'hybrid' method which is simple and efficient on tackling sound radiation problems for complex orthotropic panels, especially… More >

Jianxin Zhu, Zengsi Chen, Zheqi Shen

CMES-Computer Modeling in Engineering & Sciences, Vol.83, No.5, pp. 547-560, 2012, DOI:10.3970/cmes.2012.083.547

Abstract An acoustic waveguide with continuously varying sound speed is discussed in this paper. When the waveguide is open along the depth, the perfectly matched layer (PML) is used to terminate the infinite domain. Since the sound speed is gradually varied, the density is assumed as constant in each fluid layer. For this waveguide, it is shown that the mode relation is derived by using the differential transfer matrix method (DTMM). To solve leaky and PML modes, Newton's iteration is applied, and Chebyshev pseudospectral method is used for obtaining initial guesses. The solutions are with high accuracy. More >

M.R. Myers¹, A.B. Jorge², D.E. Yuhas³, D.G. Walker¹

CMES-Computer Modeling in Engineering & Sciences, Vol.83, No.3, pp. 221-248, 2012, DOI:10.3970/cmes.2012.083.221

Abstract An adaptive extended Kalman filter is developed and investigated for a transient heat transfer problem in which a high heat flux spot source is applied on one side of a thin plate and ultrasonic pulse time of flight is measured between spatially separated transducers on the opposite side of the plate. The novel approach is based on the uncertainty in the state model covariance and leverages trends in the extended Kalman filter covariance to drive changes to the state model covariance during convergence. This work is an integral part of an effort to develop a system capable of locating the… More >

A. Brancati¹, M. H. Aliabadi¹, A. Milazzo²

CMES-Computer Modeling in Engineering & Sciences, Vol.78, No.1, pp. 1-24, 2011, DOI:10.3970/cmes.2011.078.001

Abstract This paper presents an improved adaptive cross approximation (ACA) approach developed in conjunction with the Hierarchical format matrix and the GMRES solver. A novel scheme to generate the cluster tree (based upon preliminary considerations of the prescribed boundary conditions) and an improved ACA algorithm (approximating the system matrix for mixed Robin conditions) are described. The asymptotic smoothness property of a kernel generated by a linear combination of two asymptotic smooth kernels is demonstrated. Numerical results show the new approach to be up to 50% faster than the conventional ACA approach. More >

S. Bargmann, P. Steinmann¹

CMES-Computer Modeling in Engineering & Sciences, Vol.9, No.2, pp. 133-150, 2005, DOI:10.3970/cmes.2005.009.133

Abstract The present contribution is concerned with the modeling and computation of non-classical heat conduction. In the 90s Green and Naghdi presented a new theory which is fully consistent. We suggest a solution method based on finite elements for the spatial as well as for the temporal discretization. A numerical example is compared to existing experimental results in order to illustrate the performance of the method. More >