To investigate the effects of different organic acid additives and their concentrations on the fermentation quality and bacterial community of paper mulberry silage, paper mulberry was left untreated (control) or was treated with ethylenediaminetetraacetic acid (EDTA), propionic acid (PA) or citric acid (CA), the amount of each additive was 2 g.kg−1 FM, 5 g.kg−1 FM and g.kg−1 FM. All groups were ensiled for 3, 7, 15, 30 and 60 days. Compared to the control, adding EDTA reduced protein breakdown, preserved more water-soluble carbohydrates of the silages (WSCs, 24.74 g.kg−1 DM), and high concentrations of EDTA inhibited the activity of undesirable microorganisms. Adding PA increased the abundance of Lactiplantibacillus and decreased the abundance of Enterococcus, and it caused a rapid decrease in the pH of the silage at an early stage (from 6.50 to 5.31) while altering the microbiota, and low concentrations of PA resulted in high LA (66.22 g.kg−1 DM) concentration and low PA (9.92 g.kg−1 DM) concentration at 60 days of ensiling. Different concentrations of additives altered the microbial community of paper mulberry to different degrees. High concentrations of PA and CA can increase the abundance of Lactiplantibacillus. High concentrations of CA resulted in a rapid decrease in silage pH at an early stage and higher WSC concentration. These results suggest that EDTA, PA and CA can be used as additives to improve the quality of paper mulberry silage.
The direct torque control (DTC) and direct force control (DFC) method were introduced to reduce the torque and levitation force ripple in single-winding bearingless switched reluctance motors (SWBSRMs). However, it still has some disadvantages. Firstly, the flux-linkage control is not suitable for the DTC method in SWBSRMs. On the one hand, it can increase the torque ripple. On the other hand, the RMS current can be increased and then the torque-ampere ratio is decreased. Secondly, the vectors selection is also unreasonable, which can increase the torque ripple further. In order to solve these problems, an improved control method based on DTC and DFC method for SWBSRMs is proposed in this paper, which can obtain high torque-ampere ratio and low torque ripple simultaneously. In the proposed method, the flux-linkage loop control is not needed and the space voltage vector table is improved. The experimental results show that the torque ripple is reduced by 66.7%, the torque-ampere ratio is increased by 200% and the switching times in one electrical period are reduced by 47.3%. Index Terms-single-winding bearingless switched reluctance motor, direct torque control, direct force control, torque ripple, torque-ampere ratio. NOMENCLATURE θ Rotor angular position. θsr Angle between stator and rotor flux linkage. ia1-ia4 Winding currents of phase A in BSRMs. Ta Instantaneous torque of phase A. Fα , Fβ Radial forces on the direction of α-axis and β-axis, respectively. p0 Number of rotor poles. Lm Mutual inductance. Ls , Lr Stator and rotor inductances amplitude, respectively. Ψs ,Ψr Stator and rotor flux-linkage amplitude, respectively. σ Leakage inductance coefficient. is Current of stator winding in SRMs. c Constant 1.01. h Lamination length of the iron core. l0 Air-gap length between the stator and rotor poles. Ns Number of winding turns. r Radius of rotor. μ0 Permeability of vacuum.
Φ Abstract --The purpose of this paper is the investigation of different parameters on the performance of high efficiency switched reluctance drives. At first a rough design estimation of the geometry is calculated by hand. After that the switched reluctance machine is designed with PC-SRD, a computeraided software package developed at SPEED laboratory. To reach the best performance for a given cross-section different geometry and control parameters are varied.
Composed of a transmissive super‐twisted‐nematic(STN) liquid crystal display (LCD) and an external driving circuit system, the light printer for optical rewritable (ORW) electronic paper (e‐paper) can easily hold or change the display image, which is used as the mask pattern of ORW electronic paper.
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