Prototype Design and Feasibility Analysis for Self-Levitated Conveying

In order to avoid friction and scratching when conveying object, an acoustic levitation prototype was designed to verify the feasibility. The modal shapes and the forced harmonic shapes of the prototype are obtained by an ANSYS coupled field computation with a one-quarter symmetry model and the levitation capacity was assessed by the use of groups of simulation and physical testing. The simulation results showed that the pure flexural and mixed flexural wave shapes with different wave numbers existed at some specific frequency. The amplitude in the central point of an aluminum plate having four piezo-electric discs glued to the bottom surface was simulated for a frequency spectrum. The experimental results confirmed the theoretical results and the feasibility of the prototype and confirm that objects can be floated at several resonant frequencies under forced vibrating condition. The system can provide largest bearing capacity when both the piezoelectric disc and the plate resonances coincide

Active force control of structure-borne sound based on robust optimization subjected to an irregular cavity with uncertainties

This paper proposes a novel method of structure-borne sound analysis and active force control, which combines interval mathematics and robust optimization theorems, to achieve vibration damping and noise reduction for enclosed cavity systems with bounded uncertainty. By introducing the interference principle of sound wave, responses under control can be obtained by solving finite element equations of structural–acoustic coupling systems. Through synthetical considerations of parameter dispersion in practice, the interval quantitative model, which only needs limited sample data, is defined, and the interval Taylor extension approach is employed to further determine boundary rules of responses of structural vibration and acoustic noise. On this basis, a new interval-oriented robust optimization framework is established to seek the optimal secondary force to simultaneously minimize nominal and radius levels of sound pressure indexes at concerned space and frequency domains. A complicated engineering example of the 3-D bomb cavity is eventually presented, in which numerical and experimental results can demonstrate the usage, validity and effectiveness of the developed methodology

Effects of various administrations upon hemodynamics in a model of ischemia–reperfusion in rats.

<p>Data are the mean ± SD. Values marked with ^&&<i>P</i><0.01 are significantly different from I/R. Values marked with * <i>P</i><0.05 or ** <i>P</i><0.01 are significantly different from metoprolol. Values marked with ^†<i>P</i><0.05 or ^‡<i>P</i><0.01 are significantly different from baseline. LVSP, LVEDP and ± d<i>p</i>/dt_max represent left ventricular systolic pressure, left ventricular end-diastolic pressure, and the maximal rates of increase and decrease in LV pressure, respectively.</p

Infarct size in rats of various groups subjected to I/R injury.

<p>Representative illustrations of infarct size as stained by Evans Blue and TTC (A). Bar graphs show AAR as a percentage of the LV (B) and An as a percentage of the AAR (C). Traces of the mean values (± SD, vertical lines). ^&&<i>P</i><0.01 <i>vs</i> I/R, ^**<i>P</i><0.01 <i>vs</i> metoprolol.</p

Activity of caspase-3 in the myocardial tissues of rats of various groups.

<p>Traces of the mean values (± SD, vertical lines). ^&&<i>P</i><0.01 <i>vs</i> I/R, ^**<i>P</i><0.01 <i>vs</i> metoprolol.</p

Percentages of positive nuclei in the myocardial tissues of various groups.

<p>(A) Representative photomicrographs of <i>in situ</i> detection of DNA fragments from sham-operated rats or rats with different pretreatments subjected to 45 min of ischemia followed by 2 h of reperfusion. Arrowheads indicate positive nuclei for TUNEL staining (magnification, ×250). (B) Bar graph shows the percentages of TUNEL-positive nuclei in sham, I/R and treated groups. Traces of the mean values (± SD, vertical lines). ^&&<i>P</i><0.01 <i>vs</i> I/R, ^**<i>P</i><0.01 <i>vs</i> metoprolol. Scale bar, 40 µm.</p

Gp91<i>^phox</i> mRNA level was analyzed by real-time RT-PCR on extracted total RNA.

<p>Threshold cycles (Ct values) were normalized to their corresponding GAPDH mRNA and the comparative mRNA levels determined by the ΔΔCt method. Traces of the mean values (± SD, vertical lines). ^&&<i>P</i><0.01 <i>vs</i> I/R.</p

Effects of various administrations on mortality and arrhythmias on ischemia–reperfusion-induced arrhythmias in rats.

<p>Data are the mean ± SD. Values marked with ^&&<i>P</i><0.01 are significantly different from I/R. Values marked with * <i>P</i><0.05 or ** <i>P</i><0.01 are significantly different from metoprolol.</p