Search

Ocean currents that are produced due to motion of tides can be utilized in power extraction by using suitable turbines. The turbine should be structurally and hydrodynamically strong. In this paper, a 0.8 m horizontal axis marine current turbine (MCT) with three blades is analyzed. A 3D CAD model of a turbine is optimized using CFD and FEA tools. The performance of the turbine is based on the coefficient of power; however, the turbine should resist the loads acting on it. The fatigue load damages the turbine which is mainly due to wave loads and it must be evaluated to avoid the cost of replacing a new turbine. Only a turbine with high power coefficient and good material strength will result in a favorable design. The parameters like pitch angles, number of blades, and turbine material are modified to study the performance and structural stability of the turbine. The detailed CFD study including boundary conditions and methodology has contributed to get an insight of the flow physics. The best suitable pitch angle and number of rotor blades for the turbine are analyzed and discussed. The optimized turbine has two rotor blades with a pitch angle of 19.5° and has achieved a significant 25% increase in CP. Later, different materials are chosen to identify the variation in stress and tip deflection of the turbine blades. This will direct toward a safe design of the turbine blades.

With the increased global population, smart living is an increasingly important criteria to ensure equal opportunities for all. Therefore, what is Smart Living? The first time when we tossed this terminology seven years back, we thought reducing complexities in human life. Today we believe it more. However, smart living for all complicates the technological need further. As by all, we mean any age group, any academic background and any financial condition. Although electronics are powerful today and have enabled our digital world, many as of today have not experienced that progress. Going forward while we realize more and more electronics in our daily life, the most important question would be how. Here we show, a heterogeneous integration approach to integrate low-cost high performance interactive electronic system which are physically compliant. We are redesigning electronics to redefine its purposes to reconfigure life for all to enable smart living.

In today's digital age, the increasing dependence on information also makes us vulnerable to potential invasion of privacy and cyber security. Consider a scenario in which a hard drive is stolen, lost, or misplaced, which contains secured and valuable information. In such a case, it is important to have the ability to remotely destroy the sensitive part of the device (e.g., memory or processor) if it is not possible to regain it. Many emerging materials and even some traditional materials like silicon, aluminum, zinc oxide, tungsten, and magnesium, which are often used for logic processor and memory, show promise to be gradually dissolved upon exposure of various liquid medium. However, often these wet processes are too slow, fully destructive, and require assistance from the liquid materials and their suitable availability at the time of need. This study shows Joule heating effect induced thermal expansion and stress gradient between thermally expandable advanced polymeric material and flexible bulk monocrystalline silicon (100) to destroy high-performance solid state electronics as needed and under 10 s. This study also shows different stimuli-assisted smartphone-operated remote destructions of such complementary metal oxide semiconductor electronics.

The authors thank Swnalund Chair Professor of University of Illinois at Urbana-Champaign Prof. John Rogers for useful discussion about this paper. This publication is based upon work supported by the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under Award No. Sensor Innovation Initiative OSR-2015-Sensors-2707 and KAUST-KFUPM Special Initiative OSR-2016-KKI-2880. M.M.H. conceptualized and directed the study. J.M.N. led the study. K.M. developed the electronic circuit. K.L. assisted with human subject testing. A.A.A. helped with design. J.M.N. and M.M.H. coauthored the paper. Every author reviewed the final draft.