4 research outputs found
Electromagnetic performances and main parameter sensitivity effect on unbalance magnetic flux in a New Single‑Phase FEFSM with segmental rotor
Three-phase field excitation flux switching motor (FEFSM) with salient rotor structure has been introduced with their advantages
of rotor easy temperature elimination and controllable FEC magnetic flux. Yet, the salient rotor structure is found to
lead a longer magnetic flux path between stator and rotor parts, producing a weak flux linkage along with low torque performances.
Hence, a new structure of single-phase FEFSM using segmental rotor with non-overlap windings is proposed with
advantages of shorter magnetic flux path, light weight and robust rotor structure. Analysis on fundamental magnetic flux
characteristics, armature and FEC magnetic flux linkages, cogging torque, back-Emf, various torque capabilities, refinement
of unbalance magnetic flux, and torque-power versus speed characteristics are conducted using 2D FEA through JMAG
Designer version 15. The results show that magnetic flux amplitude ratio has been improved by 41.2% while the highest
torque and power achieved are 1.45 Nm and 343.8 W, respectively
Methods for Determining the Uncertainty of Population Estimates Derived from Satellite Imagery and Limited Survey Data: A Case Study of Bo City, Sierra Leone
This study demonstrates the use of bootstrap methods to estimate the total population of urban and periurban areas using satellite imagery and limited survey data. We conducted complete household surveys in 20 neighborhoods in the city of Bo, Sierra Leone, which collectively were home to 25,954 persons living in 1,979 residential structures. For five of those twenty sections, we quantized the rooftop areas of structures extracted from satellite images. We used bootstrap statistical methods to estimate the total population of the pooled sections, including the associated uncertainty intervals, as a function of sample size. Evaluations based either on rooftop area per person or on the mean number of occupants per residence both converged on the true population size. We demonstrate with this simulation that demographic surveys of a relatively small proportion of residences can provide a foundation for accurately estimating the total population in conjunction with aerial photographs