De-Shin Liu, Kuo-Liang Cheng, Zhen-Wei Zhuang, T. C. Lee

The International Conference on Computational & Experimental Engineering and Sciences, Vol.19, No.2, pp. 41-42, 2011, DOI:10.3970/icces.2011.019.041

Abstract High speed spindle is the key component for high precision machine center. The optimum design of spindle cooling system have to achieve to avoid the high heat produce by the build-in motor that can make great damage to the spindle bearing systems. This paper presents a new solid-fluid coupling computing method for design high speed spindle cooling system. Energy equation has been formed for a control volume within the cooling channel to describe the heat absorbing by the coolant moving in a constant speed. Finite different method is applied to solve temperature rising in the More >

K. Zhang, H. L. Duan, J. Wang

The International Conference on Computational & Experimental Engineering and Sciences, Vol.18, No.1, pp. 27-28, 2011, DOI:10.3970/icces.2011.018.027

Abstract Recently, much attention has been paid to the single walled carbon nanotube (SWCNT) bundle, which exhibits remarkable mechanical, chemical and electrical properties. Here, we present the pattern transformations of the SWCNT bundle under contraction and expansion. We first report three simple relations governing the geometry of the SWCNT bundle under no pressure. Then, due to the expansion of the bundle, a new hexagonal structure is found by using both the hybrid atom-continuum model and density functional theory. The results show that when the diameter of the nanotubes is larger than certain critical value, the nanotubes More >

V.K. Tewary¹, M. D. Vaudin²

CMC-Computers, Materials & Continua, Vol.25, No.3, pp. 265-290, 2011, DOI:10.3970/cmc.2011.025.265

Abstract A semicontiuum Green's-function-based model is proposed for analysis of averaged mechanical characteristics of Si_xGe_{1 - x}. The atomistic forces in the model are distributed at discrete lattice sites, but the Green's function is approximated by the continuum GF in the far field and by the averaged lattice GF in the near field. Averaging is achieved by replacing Si and Ge atoms by identical hypothetical atoms that are x fraction Si and (1-x) fraction Ge. The parameters of the model are derived using the atomistic model from the interatomic potential between the hypothetical atoms. The interatomic potential… More >

Qiang Li, Jie Ouyang¹, Xuejuan Li², Guorong Wu², Binxin Yang²

CMES-Computer Modeling in Engineering & Sciences, Vol.74, No.3&4, pp. 247-268, 2011, DOI:10.3970/cmes.2011.074.247

Abstract A unified mathematical model is proposed to predict the short shot, primary and secondary gas penetration phenomenon in gas-assisted injection molding (GAIM) process, where the Cross-WLF model and two-domain modified Tait equation are employed to simulate the melt viscosity and density in the whole process, respectively. The governing equations of two-phase flows including gas, air and polymer melt are solved using finite volume method with SIMPLEC technology. At first, two kinds of U-shaped gas channels are modeled, where the shape corner and generous corner cases are studied. At last, as a case study, the short More >

Ping Hu¹, Yang Xia¹, Limin Tang²

CMES-Computer Modeling in Engineering & Sciences, Vol.73, No.2, pp. 103-136, 2011, DOI:10.3970/cmes.2011.073.103

Abstract In this paper, an assumed displacement quasi-conforming finite element method with truncated polynomial expansions of in-domain displacements and derived expansions of strains is introduced. Based on the method a four-node quadrilateral flat shell element with complete quadratic polynomials for membrane and bending displacement fields is developed. Numerical tests are carried out for validation of the present element. The results show that the present element preserves all the advantages of the quasi-conforming i.e., explicit stiffness matrix, convenient post processing and free from membrane locking and shear locking. The tests also prove that the present element gives More >

Jinling Long^1,2, Bingang Xu^1,3, Xiaoming Tao¹

CMES-Computer Modeling in Engineering & Sciences, Vol.72, No.4, pp. 273-298, 2011, DOI:10.3970/cmes.2011.072.273

Abstract Moving slender threadline structures are widely used in various engineering fields. The dynamics of these systems is sometimes time dependent but in most cases follows a periodic pattern, and slender yarn motion in textile engineering is a typical problem of this category. In the present paper, we propose a nonlinear approach to model the dynamic behavior of slender threadline structures with a real example in the analysis of slender yarn motion in spinning. Moving boundary conditions of yarn are derived and a consequence of the perturbation analysis for the dimensionless governing equations provides the zero More >

Li Chen, Hui-Bao Luan, Wen-Quan Tao^*

Frontiers in Heat and Mass Transfer, Vol.1, No.2, pp. 1-11, 2010, DOI:10.5098/hmt.v1.2.3002

Abstract Multi-phase lattice Boltzmann method is applied to investigate liquid water transport in th GDL and GC. The liquid water transport processes in the GDL, near the GDL-GC interfaces and in the GC are discussed. The effects of channel land on liquid water dynamic behaviors and distribution in the GDL and GC are investigated. It is found that channel land covers the GDL-GC interface where liquid water reaches changes the water distribution near the GDL-GC interface and in the GC. While channel land is apart from the GDL-GC interface where liquid water reaches changes the effects More >

Ixtaina¹ VY y MM Mujica^1,2

Phyton-International Journal of Experimental Botany, Vol.79, pp. 95-100, 2010, DOI:10.32604/phyton.2010.79.095

Abstract The slow initial growth of Lotus tenuis limits its use to improve the Flooding Pampas grasslands by mean of its intersowing. Research on the inter and intra-population variability of seedling vigor under changing environmental conditions, and the population x environment interaction, contribute to design sowing strategies and selection criteria. The objective of this study was to evaluate the inter and intra-population phenotypic variability, under different plant densities and planting dates. Variables measured included the number of stems (Nt), and the shoot dry weight (PSa) in L. tenuis seedlings. Crown stems and PSa were determined in 5 populations… More >

Ahmad¹ S, S Gul², AKK Achakzai², M Islam¹

Phyton-International Journal of Experimental Botany, Vol.79, pp. 19-23, 2010, DOI:10.32604/phyton.2010.79.019

Abstract Seedling growth and development of Seriphidium quettense were examined under water stress (WS) and non-water stress (NWS) conditions. Seedlings were grown in pots to investigate their response to NWS conditions. Impact of WS on seedling growth was assessed in pre-existing plants grown under a semi-arid, natural environment. Seedling growth attributes were recorded on a monthly basis. Seedling growth exhibited a significant positive response under NWS conditions. Length of the main root axis at the first leaf emergence stage was 5.69 cm under NWS conditions; however, it was 4.8 cm in the natural environment (WS). At the… More >

Lovey¹ RJ, P Perissé², C V ieyra³, JC Coraglio³

Phyton-International Journal of Experimental Botany, Vol.79, pp. 5-10, 2010, DOI:10.32604/phyton.2010.79.005

Abstract Cologania broussonetii (Balb.) DC. (Fabaceae) grows from the Bolivian eastern Andes to the north west of Argentina, Cordoba hills and San Luis Province. It is recognized as a native forage. The objectives of this study were to characterize the seed, the germination and the seedling of C. broussonetii. Seed structure was characterized through free hand sections and analyzed with optical and stereoscopic microscopy. The germination assay treatments were: (1) intact non-scarfied seeds at 25 °C constant, (2) scarified seeds at 25 °C constant, (3) intact non-scarified seeds at 20-30 °C alternating, and (4) scarified seeds at 20-30… More >