Sharif Digital Repository

This paper presents experimental results on the foaming behavior and compressive properties of AlSi7-3 vol.% SiC metal foam. Elemental powders of Al, Si, SiC and TiH2 were mixed, hot compacted and foamed at 750, 780 and 810 °C. It was shown that the addition of fine SiC particles (mean diameter of 3 μm) increases the melt expansion and improves the stability of AlSi7 foam. A less drainage in the cell structure was also noticed. Meanwhile, large irregular cells in the macrostructure and a slight degradation of the mechanical properties under compressive load were observed. © 2007 Elsevier B.V. All rights reserved  

This paper describes a new capacitor sharing technique for pipeline ADCs. It enables power reduction of the first and second MDACs simultaneously. The presented noise and power analysis shows that the proposed method is about 30% more efficient than the conventional one in terms of the first and second MDACs power dissipation. A 10-bit 40MS/s pipeline ADC employing the proposed technique was designed in 90-nm CMOS technology achieving a power consumption of 4.2 mW  

The effects of SiC addition on the foaming behavior and compressive properties of AlSi7 metal foams were studied. Elemental powders of Al, Si, SiC and TiH2 were mixed, hot compacted and foamed at temperatures between 750 and 810 °C. The role of SiC volume fraction up to 10 vol.% and its particle size (3, 8 and 16 μm) was investigated. It was found that the foaming behavior of AlSi7 alloy, i.e. the maximum foam expansion and its stability, depends on the size and volume fraction of SiC particles. Increasing the amount of the ceramic particles and/or decreasing the particle size leads to less melt drainage whilst the cell structure becomes non-uniform. This is attributed to the effect of the... 

High reliability and low power consumption are the critical objectives in wireless networks and the network topology is an effective issue in these objectives. This paper investigates these two objectives in the wireless multi-hop networks simultaneously. For this purpose, a connected dominating set CDS-based topology control approach is proposed. In this approach a distributed topology control algorithm with different power adjustment measures is suggested. Our goal is to self-organize this network with minimum interference and power consumption subject to connectivity preservation. Unlike many reliability enhancement algorithms, the proposed mechanism does not compromise power consumption.... 

We report different morphologies of nanodroplets over various topographical features of the supporting substrates. The effects of different parameters such as the profile of the disjoining pressure, droplet size and the geometrical parameters are studied and discussed. Also, the effects of a coating layer on the surface of the substrate are determined. It is demonstrated that the nanodroplets at some positions are not stable and gradually move to more stable positions so that the system has less energy. For grooves this results in a series of morphology diagrams of the nanodroplets over the grooves as a function of the grooves' width and the liquid volume