Yuan Chen¹, Liangtao Duan¹, Weize Sun^{2, *}, Jingxin Xu³

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 849-859, 2020, DOI:10.32604/cmc.2020.07115

Abstract In this paper, we address the frequency estimator for 2-dimensional (2-D) complex sinusoids in the presence of white Gaussian noise. With the use of the sinc function model of the discrete Fourier transform (DFT) coefficients on the input data, a fast and accurate frequency estimator is devised, where only the DFT coefficient with the highest magnitude and its four neighbors are required. Variance analysis is also included to investigate the accuracy of the proposed algorithm. Simulation results are conducted to demonstrate the superiority of the developed scheme, in terms of the estimation performance and computational More >

Wujie Hu¹, Gonglin Yuan^{1, *}, Hongtruong Pham²

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 787-800, 2020, DOI:10.32604/cmc.2020.02993

Abstract It is well known that Newton and quasi-Newton algorithms are effective to small and medium scale smooth problems because they take full use of corresponding gradient function’s information but fail to solve nonsmooth problems. The perfect algorithm stems from concept of ‘bundle’ successfully addresses both smooth and nonsmooth complex problems, but it is regrettable that it is merely effective to small and medium optimization models since it needs to store and update relevant information of parameter’s bundle. The conjugate gradient algorithm is effective both large-scale smooth and nonsmooth optimization model since its simplicity that utilizes More >

Lili Pan¹, Cong Li^{1, *}, Samira Pouyanfar², Rongyu Chen¹, Yan Zhou¹

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 731-746, 2020, DOI:10.32604/cmc.2020.06508

Abstract With the development of deep learning and Convolutional Neural Networks (CNNs), the accuracy of automatic food recognition based on visual data have significantly improved. Some research studies have shown that the deeper the model is, the higher the accuracy is. However, very deep neural networks would be affected by the overfitting problem and also consume huge computing resources. In this paper, a new classification scheme is proposed for automatic food-ingredient recognition based on deep learning. We construct an up-to-date combinational convolutional neural network (CBNet) with a subnet merging technique. Firstly, two different neural networks are… More >

Yasir Nawaz¹, Muhammad Shoaib Arif ¹, Mairaj Bibi^{2, *}, Javeria Nawaz Abbasi², Umer Javed³, Amna Nazeer²

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 657-677, 2020, DOI:10.32604/cmc.2020.08584

Abstract Present contribution is concerned with the construction and application of a numerical method for the fluid flow problem over a linearly stretching surface with the modification of standard Gradient descent Algorithm to solve the resulted difference equation. The flow problem is constructed using continuity, and Navier Stoke equations and these PDEs are further converted into boundary value problem by applying suitable similarity transformations. A central finite difference method is proposed that gives third-order accuracy using three grid points. The stability conditions of the present proposed method using a Gauss-Seidel iterative procedure is found using VonNeumann… More >

Behrouz Karami¹, Maziar Janghorban¹, Timon Rabczuk^{2, *}

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 607-629, 2020, DOI:10.32604/cmc.2020.08032

Abstract This study investigates the forced vibration of functionally graded hexagonal nano-size plates for the first time. A quasi-three-dimensional (3D) plate theory including stretching effect is used to model the anisotropic plate as a continuum one where smallscale effects are considered based on nonlocal strain gradient theory. Also, the plate is assumed on a Pasternak foundation in which normal and transverse shear loads are taken into account. The governing equations of motion are obtained via the Hamiltonian principles which are solved using analytical based methods by means of Navier’s approximation. The influences of the exponential factor, More >

Junyan Ni¹, Xincun Zhuang^{2, 3}, Magd Abdel Wahab^{4, 5, *}

CMC-Computers, Materials & Continua, Vol.62, No.2, pp. 495-523, 2020, DOI:10.32604/cmc.2020.08448

Abstract Residual stress after welding has negative effects on the service life of welded steel components or structures. This work reviews three most commonly used methods for predicting residual stress, namely, empirical, semi-empirical and process simulation methods. Basic principles adopted by these methods are introduced. The features and limitations of each method are discussed as well. The empirical method is the most practical but its accuracy relies heavily on experiments. Mechanical theories are employed in the semi-empirical method, while other aspects, such as temperature variation and phase transformation, are simply ignored. The process simulation method has More >

Yufeng Ma¹, Xuanang Gong¹, Puyou Jia^2,*

Journal of Renewable Materials, Vol.8, No.1, pp. 45-55, 2020, DOI:10.32604/jrm.2020.08621 - 01 January 2020

Abstract In order to improve the comprehensive performance of phenolic foam, 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) was grafted with itaconic acid (ITA) (DOPO-g-ITA) to modify microcrystalline cellulose (MCC). DOPO-g-ITA modified MCC (DIMMCC) was used to prepare composite phenolic foam (DCPF). The structures of DIMMCC were verified by Fourier transform infrared spectroscopy (FT-IR). The microstructure and crystalline property were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD) respectively. Compared with MCC, the crystallinity of DIMMCC was dramatically decreased, but the diffraction peak positions were unchanged. Thermal stability was decreased, and T_i decreased by 45.0°C. The residual carbon (600°C) More >

Maud Chemin, Céline Moreau, Bernard Cathala, Ana Villares^*

Journal of Renewable Materials, Vol.8, No.1, pp. 29-43, 2020, DOI:10.32604/jrm.2020.07850 - 01 January 2020

Abstract In this work, we studied the adsorption of modified cellulose nanocrystals onto solid surfaces by quartz crystal microbalance with dissipation monitoring (QCM-D). Cellulose nanocrystals obtained from tunicate (CNC) were modified at reducing end by amidation reactions. Two different functionalities were investigated: a polyamine dendrimer (CNC-NH₂), which interacts with gold surface by the amine groups; and a biotin moiety (CNC-Biot), which has a strong affinity for the protein streptavidin (SAV). QCM-D results revealed different adsorption behaviors between modified and unmodified CNCs. Hence, unmodified CNCs covered almost all the surface forming a rigid and flat layer whereas reducing More >

Haitao Li^1,*, Huizhong Zhang¹, Zhenyu Qiu¹, Jingwen Su², Dongdong Wei³, Rodolfo Lorenzo⁴, Conggan Yuan³, Hongzheng Liu⁵, Chungui Zhou⁶

Journal of Renewable Materials, Vol.8, No.1, pp. 13-27, 2020, DOI:10.32604/jrm.2020.09341 - 01 January 2020

Abstract In order to investigate the basic mechanical properties and stress strain relationship model for bamboo scrimber manufactured based on a new technique, a large quantities of experiments have been carried out. Based on the analysis of the test results, the following conclusions can be drawn. Two main typical failure modes were classified for bamboo scrimber specimens both under tension parallel to grain and tension perpendicular to grain. Brittle failure happened for all tensile tests. The slope values for the elastic stages have bigger discreteness compared with those for the specimens under tensile parallel to grain.… More >

Haiyang Ding^1,2,3,4,5, Xiaohua Yang^1,2,3,4,5, Lina Xu^1,2,3,4,5, Shouhai Li^1,2,3,4,5, Jianling Xia^1,2,3,4,5, Mei Li^1,2,3,4,5,*

Journal of Renewable Materials, Vol.8, No.1, pp. 1-11, 2020, DOI:10.32604/jrm.2020.08165 - 01 January 2020

Abstract Thermosetting polyurethanes are widely used in various fields owing to their excellent elasticity, strength and solvent resistance. Three environmental friendly propyl gallate-based self-healing polyurethanes were prepared from polyurethane prepolymers with varying isocyanate content. The thermal stabilities of the polyurethanes were tested using thermogravimetric analysis. Their self-healing and mechanical properties were analyzed using a universal testing machine and dynamic thermomechanical analysis. The polyurethanes were found with high self-healing ability and excellent mechanical properties due to the absence of phenolic carbamate. These qualities improved with increased isocyanate content and the prolonged selfhealing time. We found, therefore, that More >