Yi TANG^1,*, Carlos Alberto BUSSO²

BIOCELL, Vol.42, No.2, pp. 61-66, 2018, DOI:10.32604/biocell.2018.07015

Abstract Elm (Ulmus pumila L.) is the dominant tree species in the sparse elm woodland, the original vegetation in the Horqin Sandy Land. The effects of changes in precipitation on U. pumila trees have not been fully studied. We determined a dynamic model by considering the five stages in the U. pumila life cycle, i.e. seed, seedling, and juvenile, mature and over-mature tree stages. The effects of changes in precipitation on population density and age structure were then evaluated. Population density, after averaging all study developmental morphology stages, ranged from 16.67 individuals/m2 to 25.01 individuals/m2 under More >

G. Suguinoshita¹, C. H. Silva¹, M. A. Luersen^{1, *}

CMES-Computer Modeling in Engineering & Sciences, Vol.117, No.1, pp. 59-71, 2018, DOI:10.31614/cmes.2018.01777

Abstract This paper describes a study of the effects of graphite nodule characteristics on a subsurface crack in austempered ductile iron (ADI). A representative specimen of ADI, subjected to sliding contact load, is modeled using finite elements aiming to obtain the shear stress intensity factor (K_II). The parameters varied were (i) the nodule diameter (two different values were considered), (ii) the distance between the nodule and the tip of the crack and (iii) the position of the load relative to the tip of the crack. The results of the numerical simulations show that the smaller diameter nodule More >

C. Gopinath^{1, *}, M. Rajvikram¹

CMES-Computer Modeling in Engineering & Sciences, Vol.115, No.3, pp. 359-386, 2018, DOI:10.3970/cmes.2018.06143

Abstract This research paper proposes a single phase fifteen level inverter for a grid connected PV system. The proposed inverter is also called cascaded asymmetric multilevel inverter. By adopting appropriate hybrid modulation technique improved output voltage is obtained with minimum number of power electronic switches. By reducing the number of gate triggering circuits of the switches, the size and power consumption of the driving circuits can be reduced. The total harmonic distortion of the output of the inverter is improved by this inverter. The proposed inverter developed by cascading a full bridge inverter with modified H More >

Haitao Liao¹

CMES-Computer Modeling in Engineering & Sciences, Vol.115, No.2, pp. 233-262, 2018, DOI:10.3970/cmes.2018.01004

Abstract A hybrid method combined the reduced Sequential Quadratic Programming (SQP) method with the harmonic balance method has been developed to analyze the characteristics of mode localization and internal resonance of nonlinear bladed disks. With the aid of harmonic balance method, the nonlinear equality constraints for the constrained optimization problem are constructed. The reduced SQP method is then utilized to deal with the original constrained optimization problem. Applying the null space decomposition technique to the harmonic balance algebraic equations results in the vanishing of the nonlinear equality constraints and a simple optimization problem involving only upper More >

V. Venkatachalam^{1, *}, D. Prabhakaran¹

CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.3, pp. 321-334, 2018, DOI:10.3970/cmes.2018.114.321

Abstract This paper presents, using Lyapunov-Krasovskii functional technique combined with reciprocal convex lemma is considered for a networked control temperature control system with additive time-varying-delays. In the stability analysis, a new LK functional is assumed, and take the time-derivative of the (LK) functional, using reciprocal convex combination technique was employed to obtain less conservative stability criteria. Finally, the proposed stability analysis culminates into a stability criterion in the LMI (linear matrix inequalities) framework. The results obtained are in accordance with the theoretically obtained in the temperature control system and they are closer to the standard benchmark More >

Kuntao Ye^1,*, Yan Luo¹, Yingtao Jiang^2,*

CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.3, pp. 261-276, 2018, DOI:10.3970/cmes.2018.114.261

Abstract Torsional micromirror devices have been widely used in micro displays, RF switches, optical communications, and optical coherence tomography systems. In order to study the stability of electrostatically driven torsional micromirror system with double bottom plates and two voltage sources, a dimensionless, two degrees of freedom (2-DoF) dynamic model was constructed. Governed by the dimensionless phase space model equation, the pull-in and bifurcation phenomena were analyzed using the Hamiltonian method and numerical simulation. In particular, the influence of the damping coefficient and the torsion-bending coupling effect on the phase trajectory was investigated. Furthermore, the conditions that… More >

Dongkai Shen^1,2,+, Qian Zhang¹, Yixuan Wang^1,*, Huiqing Ge^3,*, Zujin Luo^4,+

CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.2, pp. 117-139, 2018, DOI:10.3970/cmes.2018.114.117

Abstract A pressure controlled mechanical ventilator with an automatic secretion clearance function can improve secretion clearance safely and efficiently. Studies on secretion clearance by pressure controlled systems show that these are suited for clinical applications. However, these studies are based on a single lung electric model and neglect the coupling between the two lungs. The research methods applied are too complex for the analysis of a multi-parameter system. In order to understand the functioning of the human respiratory system, this paper develops a dimensionless mathematical model of double-lung mechanical ventilation system with a secretion clearance function. More >

Fouad LAOUTID^1,*, Valeriia KARASEVA¹, Lucie COSTES^{1, 2}, Sylvain BROHEZ², Rosica MINCHEVA¹, Philippe DUBOIS¹

Journal of Renewable Materials, Vol.6, No.6, pp. 559-572, 2018, DOI:10.32604/JRM.2018.00004

Abstract In this study, tannic acid (TA) was investigated as flame retardant agent for PLA. Different strategies to modify its thermal degradation pathway have been explored in order to improve its charring effect. The first one consists in combining TA with organomodified montmorillonite (oMMT), and enables limiting the thermo-oxidative degradation of TA and promoting the formation of an effective char layer. Flame-retardant (FR) behavior of PLA-based composition has been found to be positively impacted by this combination since a reduction of the peak of Heat Release Rate (PHRR), more important than the value recorded when oMMT More >

Ibtissem Moussa¹, Noureddine Baaka¹, Ramzi Khiari^1,2,3*, Ali Moussa⁴, Gérard Mortha³, Mohamed Farouk Mhenni¹

Journal of Renewable Materials, Vol.6, No.1, pp. 55-67, 2018, DOI:10.7569/JRM.2017.634141

Abstract Natural dyes have become an interesting subject of study because of their better ecological properties in comparison to their synthetic counterparts. This article concerns the dyeing of wool, silk, and polyamide fabrics with natural dyes extracted from almond shells and stems. The developed method of dyeing by these extracts is interesting and very attractive for several reasons: firstly, the extracts used are the black liquor discharged from the industries of delignification, which is a chemical process for removing lignin from agricultural wastes to produce a cellulosic fiber; (ii) these natural dyes are renewable and available More >

Hangjun Zhou^1,2,*, Guang Sun¹, Sha Fu¹, Wangdong Jiang¹, Tingting Xie³, Danqing Duan¹

CMC-Computers, Materials & Continua, Vol.56, No.1, pp. 73-89, 2018, DOI:10.3970/cmc.2018.02411

Abstract In the large-scale Distributed Virtual Environment (DVE) multimedia systems, one of key challenges is to distributedly preserve causal order delivery of messages in real time. Most of the existing causal order control approaches with real-time constraints use vector time as causal control information which is closely coupled with system scales. As the scale expands, each message is attached a large amount of control information that introduces too much network transmission overhead to maintain the real-time causal order delivery. In this article, a novel Lightweight Real-Time Causal Order (LRTCO) algorithm is proposed for large-scale DVE multimedia More >