This article describes a design process for a new pediatric ventricular assist device, the PediaFlow. The pump is embodied in a magnetically levitated turbodynamic design that was developed explicitly based on the requirements for chronic support of infants and small children. The procedure entailed the consideration of multiple pump topologies, from which an axial mixed-flow configuration was ...

To achieve both accumulator pressure regulation and generator power tracking for a Compressed Air Energy Storage (CAES) system, a nonlinear controller designed base on an energy based Lyapunov function. The control inputs for the storage system are the pump/motor displacements inside the hydraulic transformer and the liquid piston air compressor/expander. While the pump/motor inside the liquid ...

Radon-222 activity concentration has been monitored since 1999 in an underground limestone quarry located in Vincennes, near Paris, France. It is homogeneous in summer, with an average value of 1700 Bq m(-3), and varies from 730 to 1450 Bq m(-3) in winter, indicating natural ventilation with a rate ranging from 0.5 to 2.4 x 10(-6) s(-1) (0.04-0.22 day(-1)). This hypothesis is supported by measu...

[1] On the basis of extensive laboratory and field tests of electrochemical concentration cell (ECC) ozonesondes, a height-dependent artifact in ozone profile measurements was found that is primarily due to side reactions of the phosphate buffers used in the ‘‘standard’’ 1% potassium iodide sensing solution. The influence of the buffers was revealed as a result of new, direct measurements of th...

We studied, for the first time to our knowledge, transient stimulated Raman scattering in H(2)- D(2) and H(2)- CH(4) gas mixtures excited with 200-fs and 2-ps, 390-nm pulses. Depending on the composition and partial pressure, of those gases, we observed approximately 40 output lines simultaneously. Under optimum conditions a conversion efficiency of as much as 8% in the combination Raman line a...

Capillaries recruit when pulmonary arterial pressure rises. The duration of increased pressure imposed in such experiments is usually on the order of minutes, although recent work shows that the recruitment response can occur in <4 s. In the present study, we investigate whether the brief pressure rise during cardiac systole can also cause recruitment and whether the recruitment is maintained d...

Pumps are fluid machines whose uses very broad and important, ranging from industry to household needs. Selection of pump performance characteristics is important must be adjusted the needs which include: discharge, head, power, rotation. The obtained through testing. In connection with importance information about characteristics, this research activity efforts will made test centrifugal pumps...

This study proposes both replenishing type and leaking type valve-pump parallel controlled systems, and then establishes their mathematical principle models and simulated numerical models. Comparative analysis of performances and parameters of the pump controlled system and valve-pump parallel controlled system indicate that the proposed systems can respond faster with high efficiency than the ...

Electrical failure during cardiopulmonary bypass (CPB) has previously been reported to occur in 1 of every 1500 cases. Most heart-lung machine pump consoles are equipped with built-in battery back-up units. Battery run times of these devices are variable and have not been reported. Different conditions of use can extend battery life in the event of electrical failure. This study was designed to...