In this study cross section geometry and material of gasket in proton exchange membrane (PEM) fuel cells have been investigated to achieve optimized fuel cell in terms of energy efficiency. The role of gaskets in fuel cells is sealing of gas flow channels and preventing from combination of them. In a PEM stack, gasket with approved geometry that suffers more stress has better sealing. For this ...

To manage the increasing static leakage in low power applications, solutions for leakage reduction are sought at the device design and process technology levels. In this paper, 90nm, 70nm and 50 nm groovedgate nMOS devices are simulated using Silvaco device simulator. By changing the corner angle and adjusting few structural parameters, static leakage reduction is achieved in grooved nMOSFETS i...

The paper documents a new transformer model in ATPDraw called XFMR. This model handles 3-phase transformers with two or three windings. Autotransformers and all Wye and Delta couplings are supported. The model includes an inverse inductance matrix for the leakage description, optional frequency dependent winding resistance, capacitive coupling, and a topologically correct core model (3and 5-leg...

The effects of tip-gap size on the tip-leakage vortical structures and velocity and pressure fields are investigated using large-eddy simulation, with the objective of providing guidelines for controlling tip-leakage cavitation and viscous losses associated with the tip-leakage flow. The effects of tip-gap size on the generation and evolution of the end-wall vortical structures are discussed by...

Tip clearance between blade end and shroud is inevitable in pump operation and of great importance on pump energy performance and pressure fluctuation. As the tip clearance size increases, the head and efficiency of the mixed flow pump drop accordingly. The simulation results show that the development of a leakage vortex is observed as the tip clearance increases, and the trajectory of this lea...

In this paper, we propose a leakage reduction technique. Because high leakage currents in deep submicron regimes are becoming a major contributor to total power dissipation of CMOS circuits. Sub threshold leakage current plays a very important role in power dissipation. So to reduce the sub threshold leakage current we proposed an adaptive voltage level (AVL) technique. Which optimize the overa...

This report introduces HotLeakage, an architectural model for subthreshold and gate leakage that we have developed here at the University of Virginia. The most important features of HotLeakage are the explicit inclusion of temperature, voltage, gate leakage, and parameter variations, and the ability to recalculate leakage currents dynamically as temperature and voltage change due to operating c...

introduction: the provision of an effective apical seal is an essential factor when choosing an appropriate material for success of root-end surgeries. root-end resection, preparation and obturation should provide an adequate apical seal. the aim of this in vitro study was to investigate bacterial and dye microleakage of four different root-end filling materials and compare the efficacy of thes...

Air leakage through the building enclosure can have a significant impact on heating and cooling loads. Unfortunately, the measurement of air leakage through enclosure systems and components can be very difficult in practice. Inaccurate quantification of air leakage can affect building performance and may lead to incorrectly-sized mechanical systems and unreliable results from whole building ene...

With the heater pipeline leakage experiment conducted on the experiment table, inner pipeline leakage of heater was studied through the leakage failure detection system. The frequency distribution and the amplitude of acoustic emission signals of leakage versus internal pressure were analyzed. Variations of signals versus leakage aperture and dissemination distance were summarized. According to...