Abstract-A main challenge in designing line-start permanent magnet synchronous motors is synchronization analysis and determination. The transient time-step finite element simulations are often required in the design process, which is computationally expensive. An attractive alternative is to use an analytical synchronization model, which is time efficient and thus viable to be included in an optimization procedure. In this paper, two variants of the energy-based analytical synchronization model are proposed. Their viability and performance are compared with those of the existing analytical method and validated by transient finite element simulations. It is shown that the proposed methods have a better resolution and accuracy in determining the synchronization status of line-start permanent magnet motors.

This study presents two novel theoretical models to elucidate frequency sensitive nuclear mechanisms in low-intensity ultrasound enhanced bioeffects. In contrast to the typical 1.5 MHz pulsed ultrasound regime, our group previously experimentally confirmed that ultrasound stimulation of anchored chondrocytes at resonant frequency maximized gene expression of load inducible genes which are regulatory markers for cellular response to external stimuli. However, ERK phosphorylation displayed no frequency dependency, suggesting that the biochemical mechanisms involved in enhanced gene expression is downstream of ERK phosphorylation. To elucidate such underlying mechanisms, this study presents a theoretical model of an anchored cell, representing an in vitro chondrocyte, in an ultrasound field. The model results showed that the mechanical energy storage is maximized at the chondrocyte’s resonant frequency and the energy density in the nucleus is almost twice as high as in the cytoplasm. Next, a mechanochemical model was developed to link the mechanical stimulation of ultrasound and the increased mechanical energy density in the nucleus to the downstream targets of the ERK pathway. This study showed for the first time that ultrasound stimulation induces frequency dependent gene expression as a result of altered rates of transcription factors binding to chromatin.

Marine ecosystems are expected to face severe impacts due to climate change (IPCC, 2019). Recognition of the potential effect that alterations in ocean temperatures, circulation, seasonality and biogeochemical cycles will have on species distributions, life histories and trophic flows has prompted, in recent years, an accelerated effort to anticipate ecosystem response to climatic drivers (Freer, Partridge, Tarling, Collins, & Genner, 2018). This is particularly daunting for higher trophic levels and for species whose life history and habitats span large spatial and temporal scales like baleen whales. The complexities of biological and oceanographic processes and their interactions are a major challenge to accurately predicting how marine ecosystems respond to climatic

This paper presents an analytical method for modelling the no-load air gap flux density of a surface-mounted and a consequent-pole linear Vernier hybrid machine (LVHM). The approach is based on simple magneto-motive force (MMF) and permeance functions to account for the doubly-slotted air gap of the LVHM. These models are used to determine the flux linkage, induced electromotive force (EMF) and average thrust force of each machine. The accuracy of the two analytical models is validated by comparison with 2D finite element method (FEM) solutions. Based on the analytical models, it is found that the working harmonics of both surface-mounted and consequent-pole LVHMs are essentially the same. However, the magnitudes of these working harmonics in the consequent-pole LVHM are invariably greater than those of surface-mounted LVHM. Further, using the analytical model, the contribution to the thrust force of the machine by each individual working harmonic can be shown clearly, and is used to explain why the consequent-pole LVHM has improved performance despite using only 50% of the permanent magnet (PM) material compared to the surface-mounted LVHM.