Di Wu¹, Wei Gao^1,2, Chongmin Song¹, Zhen Luo³

CMES-Computer Modeling in Engineering & Sciences, Vol.108, No.5, pp. 331-373, 2015, DOI:10.3970/cmes.2015.108.331

Abstract Two novel mathematical programming approaches are proposed to separately assess non-deterministic behaviour and stability of engineering structures against disparate uncertainties. Within the proposed computational schemes, uncertainties attributed by the material properties, loading regimes, as well as environmental influences are simultaneously incorporated and modelled by the interval approach. The proposed mathematical programming approaches proficiently transform the uncertain structural analyses into deterministic mathematical programs. Two essential aspects of structural analysis, namely linear structural behaviour and bifurcation buckling, have been explicitly investigated. Diverse verifications have been implemented to justify the accuracy and computational efficiency of the proposed approaches More >

Delfim Soares Jr.¹

CMES-Computer Modeling in Engineering & Sciences, Vol.107, No.3, pp. 223-247, 2015, DOI:10.3970/cmes.2015.107.223

Abstract In this work, an explicit time marching procedure, with solution-adaptive time integration parameters, is introduced for the analysis of hyperbolic models. The proposed technique is conditionally-stable, second-order accurate and it has controllable algorithm dissipation, which locally adapts at each time step, according to the computed solution. Thus, spurious modes can be more effectively dissipated and accuracy is improved. Since this is an explicit time integration technique, the new procedure is very efficient, requiring no system of equations to be dealt with at each time-step. Moreover, the technique is simple and easy to implement, being based More >

Marcin Kamiński², Jacek Szafran³

CMES-Computer Modeling in Engineering & Sciences, Vol.107, No.1, pp. 27-57, 2015, DOI:10.3970/cmes.2015.107.027

Abstract Basic probabilistic characteristics and reliability indices of critical forces for high steel skeletal towers are numerically modeled by using the Stochastic, perturbation-based Finite Element Method. It is implemented together with the Weighted Least Squares Method and compared with the Monte-Carlo simulation as well as with the semi-analytical Probabilistic FEM. The Finite Element Method solution to the stability problem for a full 3D model of a tower accounts for both first and second order effects known from the engineering codes as the so-called P-delta effect. Two different Gaussian input random variables are adopted here – Young More >

Delfim Soares Jr.¹

CMES-Computer Modeling in Engineering & Sciences, Vol.105, No.5, pp. 341-360, 2015, DOI:10.3970/cmes.2015.105.341

Abstract In this work, a second-order time-marching procedure for dynamics is discussed, in which enhanced accuracy is enabled. The new technique is unconditionally stable (according to its parameter selection), it has no amplitude decay or overshooting, and it provides reduced period elongation errors. The method is based on displacement-velocity relations, requiring no computation of accelerations. It is efficient, simple and very easy to implement. Numerical results are presented along the paper, illustrating the good performance of the proposed technique. As it is described here, the new method has no drawbacks when compared to the Trapezoidal Rule More >

Letícia Fleck Fadel Miguel¹, Leandro Fleck Fadel Miguel², João Kaminski Jr.³

CMES-Computer Modeling in Engineering & Sciences, Vol.104, No.2, pp. 87-104, 2015, DOI:10.3970/cmes.2015.104.086

Abstract Since the half of the XX century, attention was given to the instability of structures under parametric excitation, especially under periodic loads. On the other hand, the instability of bars subjected to axial loads of impulsive type has been little studied, in spite of the practical importance of the topic. Thus, in Engineering Design it is frequently supposed, without tests or additional verifications, that an axial load of short duration can exceed the Euler critical load of the bar without inducing damage in the same.
Within this context, this paper proposes the use of the… More >

V. N. Lad¹, Z. V. P. Murthy^1,2

FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.3, pp. 241-255, 2015, DOI:10.3970/fdmp.2015.011.241

Abstract Free liquid jets are of great technical importance in a variety of applications like ink-jet printing, glass painting, spray coating and metal cutting. Here we consider the changes induced in the dynamics of such jets by the presence of obstructions at the tube exit. Using stainless steel bars of 1.5 mm diameter as obstruction objects and aqueous solutions of glycerol of varying concentrations as working fluids, we performed experiments for different configurations, including a single rod at the centre of the tube exit, two parallel rods equidistant from the centre of the tube, and a… More >

Ozbey G¹, Gorczynski R², Erin N¹

European Cytokine Network, Vol.25, No.2, pp. 30-34, 2014, DOI:10.1684/ecn.2014.0353

Abstract Measurements of cytokines in cell culture supernatants are widely used to evaluate the immune response. Cytokine levels in secretomes are usually quantified using enzyme-linked immunosorbent assays (ELISA), which have easy, sensitive, specific, rapid, cost-effective, and reproducible protocols. To our knowledge, the stability of cytokines in secretomes has not been hitherto investigated. We present data that involve; time-dependent changes during storage at +4℃, and the effects of freeze-thaw cycles in samples frozen at -80℃, instant freezing of samples with liquid nitrogen, and addition of protease inhibitors on the stability of certain cytokines (TNF-α, MIP-2, IFN-γ, IL-6, More >

Rodríguez-González RE¹, JJ Paz Hernández¹, CG Iñiguez Monroy³, EO Rueda Puente², L Avendaño-Reyes¹, M Cruz-Villegas¹, CE Ail-Catzim¹, M Stoycheva⁴, R Koytchev Zlatev⁴, P Renganathan², AM García López¹

Phyton-International Journal of Experimental Botany, Vol.83, pp. 65-70, 2014, DOI:10.32604/phyton.2014.83.065

Abstract The aim of this study was to evaluate grain yield (RG) stability of some commercial wheat varieties, and to assess the stability of other parameters which are not typically measured for grain release purposes: performance of straw (RP), weight per hectoliter (PH), white belly (PB), harvest index (IC), grain protein (PG) and gluten strength (W). The evaluation was performed with the wheat varieties Cachanilla F-2000 (C), Yécora F-70 (Y) and Triguenio F-00 (TR), in El Valle de Mexicali, Baja California under four test environments, with the application of the Eberhart and Russell model. The study More >

Haitao Liao

CMES-Computer Modeling in Engineering & Sciences, Vol.103, No.3, pp. 155-187, 2014, DOI:10.3970/cmes.2014.103.155

Abstract The improved constrained optimization harmonic balance method(COHBM) is presented to solve the Duffing oscillator with time delayed term. Within the framework of the proposed method, the analytical gradients of the objective function and nonlinear quality constraints with respect to optimization variables are formulated and the sensitivity information of the Fourier coefficients can also obtained. The general formulas of the geometrically nonlinear and time delayed terms are analytically derived, which makes the calculations of nonlinear differential equations in the frequency domain easily. A stability analysis method based on the analytical formulation of the nonlinear equality constraints More >

Yidong Bao^1,2, Dongmei Wu^1,3

CMES-Computer Modeling in Engineering & Sciences, Vol.100, No.4, pp. 277-294, 2014, DOI:10.3970/cmes.2014.100.277

Abstract Aiming at the shortcomings of mass-spring model, this paper, on the basis of preliminary studies, established a new viscoelastic soft tissue model based on meshless structure. The model is consisted of a large quantity of filled spheres, with every three spheres being connected by a spring and a Kelvin structure, which can further enhance the real-time virtual simulation operability while ensure the viscoelasticity of basic model. The stress relaxation and creep equation of the model can be derived from formula derivation. Through setting different parameters to the filled spheres, this model, with certain universal property, More >