6,760 research outputs found
Calculation of microscopic nuclear level densities based on covariant density functional theory
A microscopic method for calculating nuclear level density (NLD) based on the
covariant density functional theory (CDFT) is developed. The particle-hole
state density is calculated by combinatorial method using the single-particle
levels schemes obtained from the CDFT. Then the level densities are obtained by
taking into account collective effects such as vibration and rotation. Our
results are compared with those from other NLD models, including
phenomenological, microstatistical, and non-relativistic HFB combinatorial
models. The comparison suggests that the general trends among these models are
basically the same, except for some deviations from different NLD models. In
addition, the NLDs of the CDFT combinatorial method with normalization are
compared with experimental data, including the observed cumulative number of
levels at low excitation energy and the measured NLDs. Compared with the
existing experimental data, the CDFT combinatorial method can give reasonable
results.Comment: 9 pages, 8 figure
An Ant Optimization Model for Unrelated Parallel Machine Scheduling with Energy Consumption and Total Tardiness
A novel tread model for tire modelling using experimental modal parameters
Modal parameter model acts as an analytical model of tire, because it can represent the entire tire characteristics, when applied to the tire modelling. However, without considering the effect of transfer characteristics of adjacent tread spring elements, the accuracy of modal parameter model may be limited in previous studies. Based on contact mechanics and the modal parameter model, a novel tread model is proposed considering tread transfer characteristics, and then a modified model using the modal parameters was obtained using the novel tread model. The effects of tire external characteristics were analyzed by modifying the modal parameter static vertical model. Finally, the experimental and calculated data were compared, the proposed tread model improved the accuracy of calculation. The results show that the tread transfer characteristics significantly affect contact length, i.e., by improving the predictive accuracy by 50 %, and the effect on improving the squat of tire can be ignored. The developed model may help to optimize tire modelling
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