A Novel Method of Failure Sample Selection for Electrical Systems Using Ant Colony Optimization

The influence of failure propagation is ignored in failure sample selection based on traditional testability demonstration experiment method. Traditional failure sample selection generally causes the omission of some failures during the selection and this phenomenon could lead to some fearful risks of usage because these failures will lead to serious propagation failures. This paper proposes a new failure sample selection method to solve the problem. First, the method uses a directed graph and ant colony optimization (ACO) to obtain a subsequent failure propagation set (SFPS) based on failure propagation model and then we propose a new failure sample selection method on the basis of the number of SFPS. Compared with traditional sampling plan, this method is able to improve the coverage of testing failure samples, increase the capacity of diagnosis, and decrease the risk of using

Optimization of Low Moisture Anhydrous Ammonia (LMAA) Pretreatment for Corn Stover Enzymatic Digestibility during Hydrolysis Process

Corn stover is one of the most common lignocellulosic biomass used in bioethanol production. In bioethanol production, pretreatment is the first step to break down recalcitrant structure of biomass which is also a critical process for further sugar release and fermentation. Among all chemical pretreatment processes, ammonia is one of the base reagent, and the low moisture anhydrous ammonia (LMAA) process could minimize water and ammonia input in bioethanol production. For obtaining the optimal fermentable sugar yields with the most efficient chemical loadings and pretreating time, several factors were examined for enzymatic digestibility optimization. In LMAA pretreatment process, the ammonia loading, ammoniation time and the particle size of corn stover are the main factors for enzyme digestibility in the hydrolysis process. As the particle size of corn stover was reduced from 1mm to 0.5 mm, the anhydrous ammonia loading was increased from 0.1g to 0.18g NH3/g DM biomass under 75oC and the ammoniation incubation was extended from 72 hr to 144 hr, the enzyme digestibility would increase from 71.6% to 83.69% with about 17% increments

Revisiting phonon thermal transport in two-dimensional gallium nitride: higher-order phonon-phonon and phonon-electron scattering

Two-dimensional gallium nitride (2D-GaN) has great potential in power electronics and optoelectronics. Heat dissipation is a critical issue for these applications of 2D-GaN. Previous studies showed that higher-order phonon-phonon scattering has extremely strong effects on the lattice thermal conductivity of 2D-GaN, which exhibits noticeable discrepancies with lattice thermal conductivity calculated from molecular dynamics. In this work, it is found that the fourth-order interatomic force constants (4th-IFCs) of 2D-GaN are quite sensitive to atomic displacement in the finite different method. The effects of the four-phonon scattering can be severely overestimated with non-convergent 4th-IFCs. The lattice thermal conductivity from three-phonon scattering is reduced by 65.6% due to four-phonon scattering. The reflection symmetry allows significantly more four-phonon processes than three-phonon processes. It was previously thought the electron-phonon interactions have significant effects on the lattice thermal conductivity of two-dimensional materials. However, the effects of phonon-electron interactions on the lattice thermal conductivity of both n-type and p-type 2D-GaN at high charge carrier concentrations can be neglected due to the few phonon-electron scattering channels and the relatively strong four-phonon scattering.Comment: 6 pages, 3 figure