983 resultados para Delta Sigma Omicron. Alpha Chapter
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Optimized trial functions are used in quantum Monte Carlo and variational Monte Carlo calculations of the Li2(X 1Σ+g) potential curve. The trial functions used are a product of a Slater determinant of molecular orbitals multiplied by correlation functions of electron—nuclear and electron—electron separation. The parameters of the determinant and correlation functions are optimized simultaneously by reducing the deviations of the local energy EL (EL Ψ−1THΨT, where ΨT denotes a trial function) over a fixed sample. At the equilibrium separation, the variational Monte Carlo and quantum Monte Carlo methods recover 68% and 98% of the correlation energy, respectively. At other points on the curves, these methods yield similar accuracies.
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The growth behaviour of zero-mean-shear turbulent-mixed layer containing suspended solid particles has been studied experimentally and analysed theoretically in a two-layer fluid system. The potential model for estimating the turbulent entrainment rate of the mixed layer has also been suggested, including the results of the turbulent entrainment for pure two-layer fluid. The experimental results show that the entrainment behaviour of a mixed layer with the suspended particles is well described by the model. The relationship between the entrainment distance and the time, and the variation of the dimensionless entrainment rate E with the local Richardson number Ri1 for the suspended particles differ from that for the pure two-layer fluid by the factors-eta-1/5 and eta-1, respectively, where eta = 1 + sigma-0-DELTA-rho/DELTA-rho-0.
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An empirical study is made on the fatigue crack growth rate in ferrite-martensite dual-phase (FMDP) steel. Particular attention is given to the effect of ferrite content in the range of 24.2% to 41.5% where good fatigue resistance was found at 33.8%. Variations in ferrite content did not affect the crack growth rate when plotted against the effective stress intensity factor range which was assumed to follow a linear relation with the crack tip stress intensity factor range ΔK. A high corresponds to uniformly distributed small size ferrite and martensite. No other appreciable correlation could be ralated to the microstructure morphology of the FMDP steel. The closure stress intensity factor , however, is affected by the ferrite content with reaching a maximum value of 0.7. In general, crack growth followed the interphase between the martensite and ferrite.
Dividing the fatigue crack growth process into Stage I and II where the former would be highly sensitive to changes in ΔK and the latter would increase with ΔK depending on the ratio. The same data when correlated with the strain energy density factor range ΔS showed negligible dependence on mean stress or R ratio for Stage I crack growth. A parameter α involving the ratio of ultimate stress to yield stress, percent reduction of area and R is introduced for Stage II crack growth so that the data for different R would collapse onto a single curve with a narrow scatter band when plotted against αΔS.
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Fatigue crack growth and its threshold are investigated at a stress ratio of 0.5 for the three-point bend specimen made of Austenitic stainless steel. The effect of grain size on the crack tip plastic deformation is investigated. The results show that the threshold value Δkth increases linearly with the square root of grain size d and the growth rate is slower for materials with larger grain size. The plastic zone size and ratio for different grain sizes are different at the threshold. The maximum stress intensity factor is kmax and σys is the yield strength. At the same time, the characteristics of the plastic deformation development is discontinuous and anti-symmetric as the growth rate is increased from 2·10—8 to 10−7 mm/cycle.
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To be published in: Revista Internacional de Sociología (2011), Special Issue on Experimental and Behavioral Economics.
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(PDF contains 39 pages.)
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Missing the April issue. (PDF has 26 pages.)
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(PDF contains 34 pages.)
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(PDF contains 112 pages.)
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(PDF contains 96 pages.)
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(PDF contains 84 pages.)
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Missing November issue. (PDF contains 62 pages.)
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Missing July, August, October issues. (PDF contains 56 pages.)
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Missing June issue. (PDF contains 50 pages.)