Qiang Liu^1,*, Yanyun Zou^2,3, Xiaodong Liu⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.3, pp. 617-637, 2019, DOI:10.32604/cmes.2019.06272

Abstract Haze-fog, which is an atmospheric aerosol caused by natural or man-made factors, seriously affects the physical and mental health of human beings. PM_2.5 (a particulate matter whose diameter is smaller than or equal to 2.5 microns) is the chief culprit causing aerosol. To forecast the condition of PM_2.5, this paper adopts the related the meteorological data and air pollutes data to predict the concentration of PM_2.5. Since the meteorological data and air pollutes data are typical time series data, it is reasonable to adopt a machine learning method called Single Hidden-Layer Long Short-Term Memory Neural Network (SSHL-LSTMNN) containing memory capability… More >

Chen Ding¹, Guizhi Wang^1,*, Qi Liu²

Journal on Big Data, Vol.1, No.2, pp. 55-69, 2019, DOI:10.32604/jbd.2019.06110

Abstract Haze concentration prediction, especially PM2.5, has always been a significant focus of air quality research, which is necessary to start a deep study. Aimed at predicting the monthly average concentration of PM2.5 in Beijing, a novel method based on Monte Carlo model is conducted. In order to fully exploit the value of PM2.5 data, we take logarithmic processing of the original PM2.5 data and propose two different scales of the daily concentration and the daily chain development speed of PM2.5 respectively. The results show that these data are both approximately normal distribution. On the basis of the results, a Monte… More >

Molecular & Cellular Biomechanics, Vol.15, No.1, pp. 51-61, 2018, DOI:10.3970/mcb.2018.015.051

Abstract Tracheal stenosis is a common respiratory disease and is usually treated by stent implantation. However, the implanted stent often causes excessive hyperplasia of trachea granulation tissue, leading to the restenosis. Although surgical removal or chemical suppression can be used to alleviate the restenosis, the efficacy is limited. Thus, restenosis remains a thorny complication. We investigated this issue from the perspective of the “tress-growth”relationship. Firstly, the lower airway of 5 experimental dogs were CT-scanned to reconstruct the 3D numerical models; secondly, the implantations of the Nitinol alloy stents were numerically simulated; thirdly, 45 days after the stenting, the dogs were evaluated… More >

Ning Wang^*

Molecular & Cellular Biomechanics, Vol.7, No.1, pp. 33-44, 2010, DOI:10.3970/mcb.2010.007.033

Abstract Professor Y.C. Fung has shown that living tissues remodel extensively in response to mechanical forces such as blood pressure variations. At the cellular level, those mechanical perturbations must be perceived by individual cells. However, mechanisms of mechanochemical transduction in living cells remain a central challenge to cell biologists. Contrary to predictions by existing models of living cells, we reported previously that a local stress, applied via integrin receptors, is propagated to remote sites in the cytoplasm and is concentrated at discrete foci. Here we report that these foci of strains and stresses in the cytoplasm correspond to local peak deformation… More >

Kunigal Shivakumar¹, Anil Bhargava²

CMC-Computers, Materials & Continua, Vol.1, No.2, pp. 173-190, 2004, DOI:10.3970/cmc.2004.001.173

Abstract The fiber optic sensor (FOS) embedded perpendicular to reinforcing fibers causes an `Eye' shaped defect. The length is about 16 times fiber optic radius (R_Fos) and height is about 2R_Fos. The eye contains fiber optics in the center surrounded by an elongated resin pocket. Embedding FOS causes geometric distortion of the reinforcing fiber over a height equal to 6 to 8 R_Fos. This defect causes severe stress concentration at the root of the resin pocket, the interface (in the composite) between the optical fiber and the composite, and at 90° to load direction in the composite. The stress concentration was… More >

Zhiguo Zhang^1,*, Zhenxiao Li², Yifei Zhang³, Zhenze Wang⁴, Minzhou Luo¹

CMES-Computer Modeling in Engineering & Sciences, Vol.117, No.2, pp. 157-167, 2018, DOI:10.31614/cmes.2018.04067

Abstract OSAHS (Obstructive Sleep Apnea Hypopnea Syndrome) is a respiratory disease mainly characterized by limited and repeated pauses of breathing in sleep. Currently, the optimal treatment is to apply CPAP (Continuous Positive Airway Pressure) ventilation on the upper airway of the patient through a household respiratory machine. However, if the ventilator mask is designed improperly, it might cause the residue and repeated inhalation of CO₂, which will exert an adverse impact on the therapeutic effect. Present research numerically analyzed the CO₂ transportation inside a commercial ventilator mask (Mirage SoftGel, ResMed, Australia) based on the reconstructed 3D numerical model of a volunteer's… More >

F.L.S. Bussamra¹, E.Lucena Neto¹, W.M. Ponciano¹

CMES-Computer Modeling in Engineering & Sciences, Vol.99, No.3, pp. 255-272, 2014, DOI:10.3970/cmes.2014.099.255

Abstract Hybrid-Trefftz stress finite elements have been applied with success to the analysis of linear and non-linear problems in structural mechanics. Two independent fields are approximated: stresses within the elements and displacements on their boundary. The stress field satisfies the Trefftz constraint a priori, i.e., it is extracted from the Navier equation solution. This type of element has provided remarkable improvement in stress predictions compared to the standard displacement-based finite elements. In this work, solution of stress concentration problems is carried out by hexahedral hybrid-Trefftz stress element models. Stress concentration factors and stress intensity factors are then identified and compared with… More >

Y.C. Shiah¹, C.L. Tan², Y.H. Chen³

CMES-Computer Modeling in Engineering & Sciences, Vol.96, No.4, pp. 243-257, 2013, DOI:10.3970/cmes.2013.096.243

Abstract The present authors have recently proposed an efficient, alternative approach to numerically evaluate the fundamental solution and its derivatives for 3D general anisotropic elasticity. It is based on a double Fourier series representation of the exact, explicit form of the Green’s function derived by Ting and Lee (1997). This paper reports on the successful implementation of the fundamental solution and its derivatives based on this Fourier series scheme in the boundary element method (BEM) for 3D general anisotropic elastostatics. Some numerical examples of stress concentration problems and a crack problem are presented to demonstrate the veracity of the implementation. The… More >

Da-guo Wang^1,2, Leslie-George Tham², Qing-xiang Shui¹

CMES-Computer Modeling in Engineering & Sciences, Vol.91, No.5, pp. 355-376, 2013, DOI:10.3970/cmes.2013.091.355

Abstract A finite element method, which is the characteristic-based operatorsplitting (CBOS) algorithm, is adopted to solve unsteady incompressible Navier- Stokes (N-S) equations. In each time step, the equations are split into the diffusive part and the convective part. The convective part is discretized using the characteristic Galerkin method and solved explicitly. The moving interface is captured by the pseudo-concentration method, thus, a new dam-break model is established. Through the validation of a dam-break onto a downstream dry bed or wet bed, it is shown that the present model can accurately simulate the moving interface flows. We also study dam-break in a… More >

Jun Li¹, Shunji Yang¹, Boyun Guo^1,2, Yin Feng², Gonghui Liu^1,3

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.2, pp. 79-96, 2012, DOI:10.3970/cmes.2012.089.079

Abstract In the process of gas drilling, the mechanism of transport of the cuttings up the annulus is significant, because it controls the minimum amount of volume of the required gas, the cost of cleaning the borehole, the stability of the borewell and the drill pipe erosion, etc. However, current studies in this area are only limited to theoretical discussions. The reason why drill cuttings are of very fine sizes , in air drilling, is believed to be due to the repeated crushing action of drill bit at the bottom of the hole, and the collision between cuttings themselves and the… More >