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A transient lumped-parameter thermal model of an induction motor is developed. The energy balances and the expressions for the appropriate node couplings representing conduction and convection heat transfer between nodes, as well as the expressions for the heat capacity of each node, are presented. We also present expressions used in a Second Law analysis to calculate the entropy generation and exergy destruction rates at each node. An overall Second Law efficiency for heat transfer through the motor is then defined. The model is validated by comparing calculated temperatures with experimental data for a motor driving an electric submersible pump, showing that the lumped-parameter approximation is sufficient to accurately calculate temperature distributions in the motor and to capture temperature changes during warm-up and cooldown. Finally, the Second Law analysis is used to determine which components in the motor are contributing most to the inefficiency of the heat transfer process, providing a diagnostic tool for identification of areas in the motor where potential heat transfer enhancements would be most beneficial.

Chromosome 22q11.2 deletion syndrome (22q11DS) is associated with neurocognitive impairments. The neural substrates of cognitive impairments in 22q11DS remain poorly understood. Because the corpus callosum (CC) is found to be abnormal in a variety of neurodevelopmental disorders, we obtained volumetric measurements of the CC and its subregions, examined the relationship between these regions and neurocognition and selected genotypes within candidate genes in the 22q11.2 interval in 59 children with 22q11DS and 53 control subjects. The total CC, splenium and genu were significantly larger in children with 22q11DS and the enlargement was associated with better neurocognitive functioning in the 22q11DS group, suggestive of a compensatory increase in the CC volumes. The expected age-related increase in the volume of the CC was not seen in children with 22q11DS, indicative of dysmaturation of the CC in these children. The increased volumes in the genu, splenium and total CC in the 22q11DS group were associated with polymorphisms within the candidate genes: COMT (rs4680), ZDHHC8 (rs175174) and UFD1L (rs5992403). These findings indicate that alterations in the CC volume in children with 22q11DS are associated with cognition and specific genotypes in the 22q11.2 interval.

Determining a frequency at which a resonator resonates comprising: driving an acoustic transmitter for applying an acoustic signal to the interior of a resonator by scanning through a first range of frequencies in substantially equidistant steps of a first size; detecting a signal from an acoustic receiver arranged to detect the amplitude of an acoustic signal within the resonator produced by driving the acoustic transmitter over the first range of frequencies; determining a frequency at which a maximum occurs in the detected signal for the first range of frequencies; driving the acoustic transmitter by scanning through a second range of frequencies containing the determined frequency from the first range of frequencies, the second range being smaller than the first range, and scanning through the second range of frequencies in substantially equidistant steps of a second size which is smaller than the steps of the first size; detecting a signal from the acoustic receiver produced by driving the acoustic transmitter over the second range of frequencies and determining a frequency at which a maximum occurs in the detected signal for the second range of frequencies.