A. Rashid A. Aziz

Water-in-diesel emulsion and its micro-explosion phenomenon-review

Compression ignition engines are the most efficient internal combustion engines. They are well established products and millions of them are already on the market. As a result, alternative fuel that requires complete alteration to these types of engines would be un-economical. Water-in-diesel emulsion is a best alternative fuel for compression ignition engines that can be utilized with the existing engine setup with no engine retrofitting. It has benefits in the simultaneous reduction of both NOx and particulate matters. Furthermore, it has huge impact in the combustion efficiency improvement. Micro-explosion is the most important phenomenon of water-in-diesel emulsion inside an internal combustion engine chamber. It affects both the emission reductions and combustion efficiency improvement directly and indirectly. It is affected by the volatility of the base fuel, type of emulsion, water content, diameter of the dispersed liquid, location of the dispersed liquid and ambient conditions. This review paper addresses the influence of micro-emulsion on the combustion and emission of water-in-diesel emulsion fuel. It also presents the effect of operating parameters on the micro-emulsion.

Frequency-tunable electromagnetic energy harvester by means of damping switching

In this paper, a switching damping system that can widen the operational bandwidth of an electromagnetic vibration energy harvester is presented. In the system, the damping is switched periodically within each oscillation cycle in response to the real-time position and velocity of the devices resonator. A comprehensive timing model of switching damping device is derived analytically and its resonant frequency is computed by using the MATLAB solver. The simulated results demonstrate that natural frequency of the system can be shifted up or down for a reasonably range of natural frequency by switching the electrical induced damping. The results also indicate that for a higher damping system, the devices natural frequency can be shifted up to the range of +20.2% and -58.6% away from the initial natural frequency. However, the drawback is that the switching damping system will affects the peak output, which is highly dependent on the value of the damping.