Rapid advances in wireless communication technology recently have led to the development of sensor nodes to form wireless sensor network (WSN).However, these nodes have limited battery power and due to the nature of this technology which enables communication between nodes which can be deployed anywhere including hard-accessed area, thus it is not feasible to recharge or replace the batteries. Therefore power consumption of each sensor node should be minimized so that overall network lifetime will be increased. In order to minimize power consumption, some nodes which can be considered redundant, can be put to shutdown mode. In this paper, a shutdown technique is being proposed. The technique is Random Node Shutdown. In this technique, nodes are randomly shutdown according to the criteria and conditions defined. This technique is examined and simulated using the NS2 simulation environment to find the best scenario for the proposed algorithm.
The study explores the performance characteristics of a Z-Blade reaction type water turbine and investigates a test unit for an ideal and practical case using the governing equations derived from the principles of conservation of mass, momentum, and energy. Various analyses are conducted with consideration of the ideal and possible operating condition for low-head (3 m to 5 m) and low-flow (2.5 L/sec and below) water resources. The relationship of the fluid flow friction known as k-factor with mass flow rate and angular velocity for a Z-Blade turbine model is discussed. The measured performance of two PVC pipe sizes (0.5 inch and 1 inch) of a Z-Blade turbine is presented and evaluated against theoretical results. This work also describes the simple concept of a Z-Blade turbine for a pico-hydro application. A large variation in k-factor with a 1% difference in rotational speed and mass flow rate is presented. The coefficient k-factor is also demonstrated as a strong parameter influencing the mass flow rate and rotational speed performance. This coefficient also has a significant impact on the conversion of potential energy into power output.
The purpose of this research is to investigate the dominant parameters that influence the optimum performance of reaction typed turbine at very low water head. The concepts of conservation of mass, momentum and energy are utilised to explore performance characteristics using a graphical technique. Parametric analysis of the governing equation and experimental results were performed to show that the turbine diameter and nozzle exit area has a dynamic response to mass flow rate, angular speed, output power and efficiency. Depending on the nozzle diameter of (0.01 m, 0.006 m, and 0.008 m) and turbine pipe size with (diameter of 0.025 m and 0.015 m), six versions of prototype turbine Z-blade turbine were produced. All the turbines have been tested at 100 kPa static water pressures and below. According to a variety of experimental data for all types of turbines, the turbine diameter and nozzle exit area have a substantial impact on turbine performance, especially at high water heads. Despite differences in turbine length and nozzle exit area, more than 90 % of the pattern curves for rotational speed, water flow rate, and mechanical power were identical. Overall, the Z-blade turbine Type B outperforms, resulting in higher turbine efficiency at low head and low flow water condition.
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