Passive systems have the beneficial property that their interconnections with other passive systems result in necessarily stable systems. This vmue of passive systems can be exploited with hydraulic systems to build owerful machines that are safe and human friendly. A digculty in a plying the passivity concept to electrohydraulic systems is i a t they are not intnnsically passive. In a previous...

The annular foam breaker is one which uses the vacuum and shear force generated by the Coanda effect to break foam. Its effectiveness in destroying drilling foam has been test in wellbore flow simulation loop experimental stand. Experimental results showed that the operating pressure of the annular foam breaker should be larger than 0.6MPa and the stabilizers concentration of the foam drilling ...

In this first part of a two-part study, experiments were performed to investigate condensation of FC-72 along parallel, square micro-channels with a hydraulic diameter of 1 mm and a length of 29.9 cm, which were formed in the top surface of a solid copper plate. The condensation was achieved by rejecting heat to a counter flow of water through channels brazed to the underside of the copper plat...

Flow driven by pumping without valves is examined, motivated by biomedical applications: cardiopulmonary resuscitation (CPR) and the human fetus before the development of the heart valves. The direction of flow inside a loop of tubing which consists of (almost) rigid and flexible parts is investigated when the boundary of one end of the flexible segment is forced periodically in time. Despite t...

In this study, we developed a method for fabricating a microfluidic device with integrated large-scale all-glass valves and constructed an actuator system to control each of the valves on the device. Such a microfluidic device has advantages that allow its use in various fields, including physical, chemical, and biochemical analyses and syntheses. However, it is inefficient and difficult to int...

This paper is the first of a two-part study concerning measurement and prediction of saturated flow boiling heat transfer in a water-cooled micro-channel heat sink. In this paper, new experimental results are discussed which provide new physical insight into the unique nature of flow boiling in narrow rectangular micro-channels. The micro-channel heat sink contained 21 parallel channels having ...

BACKGROUND Although Doppler echocardiography has been shown to be accurate in assessing stenotic orifice areas in native valves, its accuracy in evaluating the prosthetic valve orifice area remains undetermined. METHODS AND RESULTS Doppler-estimated valve areas were studied for their agreement with catheter-derived Gorlin effective orifice areas and their flow dependence in five sizes (19/20-...

If the binding energy of the pulsar’s surface is not so high (the case of a neutron star), both the negative and positive charges will flow out freely from the surface of the star. The annular free flow model for γ-ray emission of pulsars is suggested in this paper. It is emphasized that: (1). Two kinds of acceleration regions (annular and core) need to be taken into account. The annular accele...

Background. Although Doppler echocardiography has been shown to be accurate in assessing stenotic orifice areas in native valves, its accuracy in evaluating the prosthetic valve orifice area remains undetermined. Methods and Results. Doppler-estimated valve areas were studied for their agreement with catheterderived Gorlin effective orifice areas and their flow dependence in five sizes (19/20-2...