A novel linear induction motor for electromagnetic aircraft launch system
A variable pole pitch linear induction motor (VPPLIM) is proposed as a new member of the family of electromagnetic aircraft launch system (EMALS). With proper designing of the variation of the pole pitch, the VPPLIM could accelerate the aircraft almost uniformly at the condition of usual AC supply, avoiding use of large scale power electronics converters. The special considerations in the design of VPPLIM, such as the structure topology and the variation of the pole pitch are discussed detailedly in the paper. The acceleration performance of the VPPLIM fed by a constant voltage constant frequency supply is analyzed by means of the quasi-steady-state 2D magnetic field model and the difference model of mover's dynamics. A two stage method is proposed to simulate the acceleration performance of the VPPLIM based on a 2D thrust table of the motor achieved by finite element method (FEM). The calculated features of the prototype VPPLIM consist well with those expected for EMALS.
Variable Pole Pitch Electromagnetic Propulsion with Ladder-Slot-Secondary Double-Sided Linear Induction Motors
In this paper, we propose a novel variable pole pitch (VPP) electromagnetic (EM) propulsion technique using a series of ladder-slot-secondary double-sided linear induction motors (LS-secondary DLIMs). An equivalent circuit is developed for the LS-secondary DLIM, which considers the distribution of the eddy current in the ladders and the end effect. This equivalent circuit forms the basis for the subsequent design, numerical analysis, and optimization. The primary purpose of the VPP EM propulsion system is to address several obstacles encountered in high-speed large-thrust applications of LIMs, such as power factor improvement, optimization considering supply frequency constraint and operating kinetics, etc. The equivalent circuit of the LS-secondary DLIM, i.e., the theoretical foundation of the VPP EM propulsion, has been validated via simulation and experimentation on a small-scale platform, which proves that the numerical analysis of the VPP EM propulsion is effective.
Studies on the composition, quality and processing of triticale. Part II. Mineral composition of grain and flour.
Mineral composition of grain and flour in 14 promising triticale strains from India are reported. The mean values for whole grain, i.e. Ca (0.47 mg/g), P (2.70 mg/g), K 4.60 mg/g, Na (352 micrograms/g), Zn (41.6 micrograms/g), Cu (7.0 micrograms/g), Fe (73.4 micrograms/g) and Mn (33.6 micrograms/g) were obtained as compared to those of flour, i.e. Ca (0.27 mg/g), P (0.97 mg/g), K (1.64 mg/g), Na (231 micrograms/g), Zn (26 micrograms/g), Cu (4.0 micrograms/g) and Mn (10.5 micrograms/g), respectively. These values were found to be considerably higher than those of wheat. Highly significant positive correlations of ash with sodium and zinc in whole grain were observed. In the case of triticale flour, highly significant positive correlations of ash with manganese, phosphorus and potassium were obtained.