4 research outputs found
Improved position offset based parameter determination of permanent magnet synchronous machines under different load conditions
© The Institution of Engineering and Technology 2017.This study proposes a novel method for the parameter determination of permanent magnet (PM) synchronous machines under different load conditions. It can identify the total dq-axis flux linkages and also the PM flux linkage separately by the addition of a pair of negative and positive position offsets. It is also noteworthy that the influence of uncertain inverter non-linearity and winding resistance is cancelled during the modelling process, and the experimental results on two different PM synchronous machines show a good agreement with the finite-element prediction results. More importantly, it shows good performance in online tracking the variation of PM flux linkage, which is an important feature for aiding the condition monitoring of PMs, for example, monitoring the temperature of PMs
Metabolic Response in Rabbit Urine to Occurrence and Relief of Unilateral Ureteral Obstruction
Ureteral
obstruction will lead clinically to hydronephrosis, which may further
develop into partial or complete loss of kidney function and even
cause permanent histological damage. However, there is little knowledge
of metabolic responses during the obstructed process and its recoverability.
In this study, a complete unilateral ureteral obstruction (CUUO) model
was established in the rabbit, and <sup>1</sup>H NMR-based metabolomic
analysis of urine was used to reveal the metabolic perturbations in
rabbits caused by CUUO and the metabolic recovery after the CUUO was
relieved. Univariate and multivariate statistical analyses were used
to identify metabolic characteristics. The gradually decreased levels
of 3-hydroxykynurenine, 3-methylhistidine, creatinine, guanidoacetate, <i>meta</i>- and <i>para</i>-hydroxyphenylacetate, and
phenylacetylglycine and the gradually increased levels of acetate,
alanine, citrate, glycine, lactate, and methionine in urine could
be regarded as potential biomarkers for the occurrence and severity
of ureteral obstruction. And the reduced levels of 3-methylhistidine,
creatinine, guanidoacetate, hippurate, <i>meta</i>-hydroxyphenylacetate,
and methylguanidine and the elevated levels of 2-aminoisobutyrate,
acetylcholine, citrate, lactate, lysine, valine, and α-ketoglutarate
in urine compared with the obstructed level could characterize the
metabolic recovery of ureteral obstruction. Our results depicted the
disturbed biochemical pathways involved in ureteral obstruction and
demonstrated the practicability of recovering renal functions for
the patients with severe hydronephrosis in clinical practice by removing
causes for obstruction
Metabolic fate and subchronic biological effects of coreâshell structured Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>-NH<sub>2</sub> nanoparticles
<p>Coreâshell structured Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>-NH<sub>2</sub> nanoparticles (Fe@Si-NPs) demonstrated outstanding potentials in drug targeting and delivery and medical imaging. However, they have limited clinical applications due to unknown chronic bio-effects and potential bio-related risks. In this study, the subchronic biological effects and metabolic fate of 20ânm Fe@Si-NPs in SpragueâDawley rats in 12âweeks were investigated by the biochemical assay and NMR-based metabonomic analysis using an intravenous model. Biofluids (plasma and urine) analysis provided the transportation, absorption, and excretion information of Fe@Si-NPs. Urine metabonome displayed a metabolic recovery while self-regulation of plasma metabonome leaded to the parallel metabolic trends between dosed and control groups in 12âweeks. And biological tissues (spleen, liver, kidney, and lung) analysis indicated liver and spleen are the targeted-organs of Fe@Si-NPs. The obvious metabolic variations responding to the biodistribution were induced by Fe@Si-NPs although no visible toxic effects were observed in these tissues. Besides the common energy metabolism response to the xenobiotics, Fe@Si-NPs also disturbed the metabolic pathways in glycerophospholipid and sphingolipid metabolism, metabolisms of purine, pyrimidine, and nicotinate. Our results provide preliminary validation for the potential use of Fe@Si-NPs in clinical medicine and give identifiable ground for the dose selection and bio-nanoagent optimization.</p
Comparative study of dual 3âphase permanent magnet machines with coil span of two slotâpitches
In this study, the electromagnetic performances of dual 3-phase permanent magnet (PM) machines with coil span of two slot-pitches are comparatively investigated. It mainly focuses on two PM machines with different slot/pole number combinations (Ns/2p), that is, the 24-slot/10-pole and 24-slot/14-pole machines (2p = Ns/2 ± 2). First, winding configurations are illustrated for these two dual 3-phase machines with 30° angle displacement. Then, the winding factor, back electromotive force, average torque, torque ripple, iron and PM losses, short-circuit (SC) current, and PM irreversible demagnetisation are analysed and compared for both machines on the conditions of healthy operation and one set of three-phase fault, that is, SC or open circuit (OC), respectively. The comparative results show that on healthy condition the 14-pole PM machine has a slightly larger torque output. Besides, on 3-phase OC condition, the 14-pole machine also performs better over-rating torque capability. In terms of iron and PM losses, the 10-pole machine has smaller iron losses but larger PM losses than the 14-pole machine. Moreover, on 3-phase SC condition, the 14-pole machine has a significantly lower risk of PM irreversible demagnetisation than the 10-pole machine, although both machines have very similar SC currents. Finally, the 24-slot/10- and 14-pole dual 3-phase PM machines are both prototyped and some tests are carried out for validation. </p