Advanced Materials Research Vols. 875-877

Abstract: An application of the RCW –Reinforced Cut Wall- on a set of four masonry buildings for council housing estate with a total of 43 lofts is presented. The performances of this low-cost base energy dissipation technique has been evaluated with some experimental on-site tests performed on a couple of specimen (40x60x30 cm) subjected to a series of cyclic quasi-static time histories with increasing intensity. Trials show the high properties of self-centering and of wide hysteretic behavior of the RCW. Numerical analyses confirm the mechanical properties and provide parameters to the evaluation of cyclic dissipation properties.

Abstract: This paper evaluates numerically some of the parameters involved in modeling the process of frost formation over a cold cylinder surface subject to the flow of humid air. Was utilized for numerical predictions the empirical Nusselt correlation from the literature, obtained in experimental studies on frost formation phenomena of frost grow over a cold cylinder surface. To predict frosting process a numerical solution was utilized, and a new correlation for Nusselt number based on the experimental correlation of Kim was estimated. For the new Nusselt correlation an optimization method that adjusts the numerical solution of modeling the frost formation process with experimental results of the frost layer thickness was used. The calculation procedure allows the estimation of the parameter K of equation. The modeling process was validated by comparison with available experimental data.

Abstract: Concrete is the main material used in most of structures in the world. The use of high strength and high performance concrete to overcome deterioration due to static and dynamic load and some environmental burden in different situation such as chloride attack, sulphate attack and etc, is increasing worldwide. Achieving to a concrete with a high quality and saving in amount of material used for producing the concrete need a proper mix design method taken into account. DOE method is considered as an effective and substantial method in implementing the concrete mix design. In this paper, specifications and all mix design calculation steps using DOE method in achieving a high strength and high performance concrete for a tall building in a coastal environment based on three concrete cubes specimens produced in the lab, are investigated. The 7 and 14 day compressive strength test were implemented on the concrete cubes. At the end, it concluded that the specified compressive strength (45 N/mm2) can be achieved on the 28th day based on DOE method.

Abstract: In this paper, we consider the numerical solution of a time-fractional diffusion equation, which is obtained from the standard diffusion equation by replacing the first order time derivative with a fractional derivative of order α, with 03-α+N^-m) , where Δt,N and m are the time step size, the polynomial degree and the regularity of the exact solution, respectively.

Abstract: The finite element method has been widely applied to numerical simulation of honeycomb paperboard, and the parametric modeling is the most important step for the simulation. In order to This paper discussed three ways of building honeycomb paperboard model using ANSYS command flow, and also introduced the CAD model import in ANSYS. The influence of cutting position of honeycomb paperboard model on compression strength was analyzed; the results showed that the influence on bulk density and the compression strength of honeycomb paperboard model can't be ignored.

Abstract: The dislocation self-organization processes in near-surface silicon layers of Si-SiO₂ during high temperature oxidization have been investigated. It was observed the complex destruction of these layers caused by relaxation of mechanical stresses. We have proposed the defect formation mechanism of near-surface layers in Si-SiO₂ structure. For self-organization processes to be explained, the synergetic method was applied. It was shown that the formation of periodical dislocation structures at the interface is a consequence of the spatial instability of the dislocation distribution in the crystal, their self-organization due to correlation effects between the oxygen diffusing along structural defects and an ensemble of dislocations.

Abstract: A numerical simulation of electric and hydrodynamic field’s distribution in an electrohydrodynamic pump is made, with the mean to simulate and to determine numerically the liquid pressure and velocity. Different parameters of the pump are analyzed.

Abstract: This paper is devoted to present an approach to model behavior of hemp fibers reinforced thermoplastic composites. Experimental investigations using common testing methods have shown that major physical dissipative phenomena which explained the behavior of polypropylene/ hemp fibers (PP/Hemp) composites took place in the matrix. Moreover these dissipative mechanisms are mainly due to matrix cracking. The behavior modeling of PP/hemp fiber composites is obtained by a two-step modeling strategy. A real based microstructure is automatic generated by own made algorithms according to the observed microstructure by X-ray tomography and constitutive behavior of the matrix is obtained using the micromechanics formalism and is implemented by a FORTRAN routine in ABAQUS® software. This approach seems to have the potential to describe behavior of such composites (PP/Hemp).

Abstract: The interaction between bentonitic clays and exchangeable cations Na+, К+, Ca++, and Mg++ is studied theoretically. It is stated that the insertion of exchangeable cations into the interlaminar space leads to reducing of the interlayer distance as compared with that calculated for the undoped clay. At that, the clay particles having Mg++ on their surface demonstrate more stable structure upon the increase of moistening. The calculation results for Mg++ compare well with the experiment performed.

Abstract: Micro turning test was performed on nickel plated roll die using ultra precision lathe and lenticular shape single crystal diamond (SCD) tools. For the test, fresh tools were used for each experiment to observe tool wear evolution at the cutting distances. Finite element method (FEM) simulation based on Lagrangian method was also used to calculate contact stress on the cutting surface during the machining process. For the tool wear measurement, scanning electron microscope (SEM) and 3D Nano View, which can provide surface topography of the tools, were used. In addition, Kistler dynamometer was utilized for cutting force measurement. From the experimental result, it was found that a dominant wear mechanism was abrasion due to high contact stresses on the cutting tool surface. And it was also observed that high cutting speed caused high wear rate but slighlty reduced the cutting forces.