a water distribution network is subjected to various abnormal conditions such as pipe breaks, pump failures, excessive demands etc. in the design period. under such conditions, the network may not be able to meet required demands at desired pressures, and becomes deficient. traditional network analysis assumes nodal demands to be satisfied and available nodal pressures are calculated. however, ...

Vacuum-assist venous drainage (VAVD) can increase venous blood return during cardiopulmonary bypass (CPB) procedures. However, the negative pressure created in the closed cardiotomy reservoir can be transmitted to the oxygenator if a nonocclusive or centrifugal arterial pump is used, resulting in bubble transgression (BT) from the gas to blood compartment of the oxygenator. We analyzed the vacu...

Micromachined vacuum pumps are one of the key components in miniature systems for chemical and biological analysis. Miniature sensors and analyzers are normally operated at the pressure range lower than a few millitorr. We are developing a micromachined vacuum pump that is comprised of a mechanical rough pump integrated with micromachined ion-pumps. The rough pump generates a low vacuum of tens...

A new electronically controlled pump has been developed for use with a cuirass in providing external negative pressure ventilation. It is smaller, lighter, and more versatile than currently available pumps and operates on a servo principle. A rotary valve between the pump and the cuirass varies the rate of extraction of air from the cuirass. The pressure within the cuirass is sensed by a pressu...

Ion pump controllers are often considered just accessories needed to power ion pumps. Only basic parameters such as the maximum power and the communication interface are considered relevant, with the power usually being overspecified, resulting in needlessly expensive controllers. However, a properly designed controller can substantially improve the ion pump performance. A controller with varia...

A new disposable insert for the arterial roller pump, the Better-Header, provides safety and functionality beyond what standard tubing provides. It automatically limits pump outlet pressure to a level determined by the user and provides a self-contained, simple means to set pump occlusion. The Better-Header consists of a Starling-like pressure relief valve connected across standard header tubin...

Although compressed gas (CO2) blowers have been used safely to aid accurate grafting during off-pump coronary bypass surgery, hemodynamic collapse due to gas embolism into the right coronary artery may occur. Supportive measures to facilitate gas clearance by increasing the coronary perfusion pressure have been reported to be successful in restoring hemodynamic stability. However, right ventric...

Gasoline direct injection provides reduced engine emissions, increased power, and increased fuel economy as compared to port fuel injection (PFI). Reduced emissions are largely due to starting the engine using high fuel pressure (up to 150 bar) and injecting into the compression stroke. During a cold start, fuel pressure must be increased from lift pump pressure (typically 4 to 6 bar) to desire...

Tip vortex cavitation is one of well known patterns of cavitation phenomenon which occurs in axial pumps. This pattern of cavitation occurs due to pressure difference between the pressure and suction sides of blades of an axial pump. Since the pressure in the pressure side of the blade is higher than the pressure in its suction side, thus a very small portion of liquid flow flows back from pres...

The back-flow of an aortic valvo-pump will reduce the pumping flow rate but can wash out the gap between the rotor and the stator, and thus can improve the antithrombogenicity of the device. To investigate the regurgitation of a 23mm OD aortic valvo-pump, its closed impeller was replaced by a cylinder and hereby the valvopump had lost its pumping function. The pressure head crossing the aortic ...