دانلود گزارش کارورزی و کار آموزی

چکیده : 

In this study, upper bound finite element (FE) limit analysis is applied to stability problems of slopes

using a nonlinear criterion. After formulating the upper bound analysis as the dual form of a second-order

cone programming (SOCP) problem, the stress field and corresponding shear strength parameters can be

determined iteratively. Thus, the nonlinear failure criterion is represented by the shear strength parameters

associated with stress so that the analysis of slope stability using a nonlinear failure criterion can be

transformed into the traditional upper bound method with a linear Mohr–Coulomb failure criterion.

Comparison with published solutions illustrates the accuracy and feasibility of the proposed method

for a simple homogeneous slope stability problem. The proposed approach is also applied to a seismic

stability problem for a rockfill dam to study the influence of different failure criterions on the upper

bound solutions. The results show that the seismic stability coefficients obtained using two different nonlinear

failure criteria are similar but that the convergence differs significantly.

چکیده : 

A version of the Particle Finite Element Method applicable to geomechanics applications is presented. A

simple rigid-plastic material model is adopted and the governing equations are cast in terms of a variational

principle which facilitates a straightforward solution via mathematical programming techniques.

In addition, frictional contact between rigid and deformable solids is accounted for using an approach

previously developed for discrete element simulations. The capabilities of the scheme is demonstrated

on a range of quasi-static and dynamic problems involving very large deformations

چکیده : 

The first theoretical study of the radical reaction C4H + C4H10 is presented. The geometries and harmonic

vibrational frequencies of all the stationary points are obtained at the MP2/6-311G** level of theory. Three

hydrogen abstraction channels are identified and the minimum energy paths (MEPs) are presented in the

work. The calculated results reveal that there exists a reactant complex for each hydrogen abstraction

channel which exhibits the nature of van der Waals complex. A dual-level direct dynamics method is

employed to calculate the rate coefficients of the title reaction. The rate coefficients for all the reaction

channels are evaluated in the temperature range of 200–500 K using the conventional transition state

theory and the variational transition state theory. The branching ratio of the title reaction is plotted

and the calculated results illustrate that reaction channel R3 contributes the most part to the overall reaction.

The comparison between theoretical and experimental results is discussed and exhibits best agreement.

The fitted three-parameter Arrhenius expression of the rate coefficients for the reaction is provided

for the convenience of future experimental measurement

چکیده : 

Given their efficacy in photosynthesis, a series of metalloporphyrins were examined using density functional

theory (DFT) and time-dependent DFT. An experimentally known zinc porphyrin has been calculated

to evaluate performance of various functionals, basis sets, computational models of solvent effect

and solvent sorts. With an alternative approach, absorption spectra of complexes (MLx, , Cd and

Hg, –4) varying substituted porphyrin Lx and metal center were investigated. It was shown that

the strongest peak at about 400 nm for MLx was attributed to the intra-porphyrin p?p transition. Substitution

of benzoic acid at the b-position of porphyrin core allows an extra intense peak at 450 nm in ML3

and ML4, but ML2 with the meso-substituted benzoic acid only displays some very weak low-energy

absorptions. Additionally, we theoretically designed [Ru(NCS)2Lx]2 and expected their possession of

advantages of polypyridyl ruthenium and porphyrin-based sensitizers. The present study reveals that

the L4 complex, [Ru(NCS)2L4]2, exhibits extra intense absorption peaks at 500 and 582 nm, allowing

for its promising application in dye-sensitized solar cells (DSSCs).