Analysis of Epidemic Model for Performance Evaluation of Rechargeable Wireless Sensor Network

Wireless sensor network (WSN) is a decentralized network system which consists of sensor nodes, and these nodes are connected through wireless link. Due to decentralized network system and resource constraint WSN faces security threat. Malware (malicious signals, worm, Trajan horse, virus etc.) attacks on the sensor node of WSN and make them paralyze and steal information from the network. Malware attack also increases the energy consumption of Sensor nodes of WSN. It just begins to spread from an infected node, and spread across the entire WSN with the help of neighboring nodes. Therefore, security of WSN against attack of malware is an inescapable need. On the basis of earlier works and consideration of charging mechanism of sensor nodes, and considering the effect of coverage and connectivity, proposed a SILRD (Susceptible - Infectious – Low Energy – Recovered –Dead) model with vital dynamics. The propose model investigates the dynamics of malware propagation in WSN and also explain sensor node’s energy consumption. The system’s stability has analyzed in terms of local and global of malware-free and endemic equilibrium. For the investigation of system dynamics, the expression of basic reproduction number has computed, which is also utilized to analyze state of malware in WSN. The effect of charging, coverage and connectivity is explained in this paper.

Power Line Charging Mechanism for Drones

The use of multirotor drones has increased dramatically in the last decade. These days, quadcopters and Vertical Takeoff and Landing (VTOL) drones can be found in many applications such as search and rescue, inspection, commercial photography, intelligence, sports, and recreation. One of the major drawbacks of electric multirotor drones is their limited flight time. Commercial drones commonly have about 20–40 min of flight time. The short flight time limits the overall usability of drones in homeland security applications where long-duration performance is required. In this paper, we present a new concept of a “power-line-charging drone”, the idea being to equip existing drones with a robotic mechanism and an onboard charger in order to allow them to land safely on power lines and then charge from the existing 100–250 V AC (50–60 Hz). This research presents several possible conceptual models for power line charging. All suggested solutions were constructed and submitted to a field experiment. Finally, the paper focuses on the optimal solution and presents the performance and possible future development of such power-line-charging drones.

Supporting the surface charging mechanism of seismic-electromagnetic phenomena by the direct measurements of the electron and hole trapping centers

<p>The mechanisms of the seismic-electromagnetic phenomena (SEP) attracted as precursors of short-term earthquake forecast have been suggested, however, it is still incompletely understood. Among the possible mechanisms of the SEP is the surface charging mechanism related to the electron and hole trapping centers in quartz. Previous studies evaluated the plausibility of the mechanism from the surface charge density by the measurement of current or potential changes. On the other hand, only a few studies have evaluated the plausibility from the direct measurements of the trapping centers’ concentration.</p><p>We have performed low-velocity friction experiments mimicking the fracture with low-frictional heating for simulated fault gouges (commercial natural quartz sands) at a normal stress of 1.0 MPa with displacements up to 1.4 m. In order to measure the concentration of the trapping centers in the simulated-fault gouges, we conducted electron spin resonance for the standard sample, TEMPOL (4-hydroxy-2,2,6,6-tetramethyl-piperidine-1-oxyl), and the gouges before and after friction. In recent decades, researchers also have obtained the concentrations of the trapping centers in the quartz damaged in the rock fracture experiments using ESR and a radical scavenger. From those concentrations with the measured or assumed surface areas, we calculated the surface charge density of the quartz and discussed the plausibility of the surface charging mechanism of the SEP.</p><p>In our friction experiments, the E’ type centers were detected at g<sub>2</sub> = 2.001 (e.g., E<sub>1</sub>’ center; ≡Si･, E<sub>S</sub>’ center; ≡Si･, E<sub>α</sub>’ center; =Si:, where − is an electron pair, : is a lone pair, and ･ is an unpaired electron) in the ESR spectra of the simulated-quartz gouges and the trapping center increased by the fracture of low-velocity friction. Assuming that the trapping centers were produced on the grain surfaces by the fracture, the range of the increase in the surface charge density was (0.21–8.0) ×10<sup>-4</sup> C/m<sup>2</sup>. The rock fracture experiments found the E<sub>1</sub>’ center, non-bridging oxygen hole center (NBOHC; ≡Si−O･), and peroxy center (≡Si−O−O･) in quartz. On the same assumption, the total surface charge density of those trapping centers and the density of the E<sub>1</sub>’ center or NBOHC were estimated as 2.7×10<sup>-1</sup> and 5.0×10<sup>-2</sup>–3.94 C/m<sup>2</sup>, respectively.</p><p>The surface charge density required for a corona discharge that can cause the SEP in the air over a flat plane is reported over 5.0×10<sup>-5</sup> C/m<sup>2</sup>. The quantities calculated above are almost enough to induce a corona discharge. The surface charges can form the electric dipoles on the fault plane, inducing the electric and magnetic fields. Our experiment showed that the fracture by fault motions could produce the surface charges on the fault. It proves that the electromagnetic abnormalities by the fault motions may also be observed through the surface charging mechanism. Therefore, our study supports that the surface charging mechanism is plausible.</p>

A study of the electrostatic charge of the coarse water droplets

The aim of this paper is introduce the results of a measurement of the electrostatic charge of water droplets during wet steam expansion. The analysis of the charge origin was done. The achieved result shows that there is not a significant charging mechanism for the fine droplets. The dependence between the specific electrical current and the amount of liquid phase collected by the probe was found. Some models were studied to determine the origin of the electrical current. Finally a model was proposed, where the el. current is generated by the disruption of thin liquid film on the surface of the probe. The charging model was later applied for the measurement of the liquid film disruption in the new wind tunnel designed for the simulation of the flow field in the steam turbines. The measurement was performed with the air as a flowing medium and two modal droplets size distribution was found.

Switching of alternative electrochemical charging mechanism inside single-walled carbon nanotubes: a quartz crystal microbalance study

The increase in charge carrier density in SWCNTs with applied potential overcomes steric hindrance to counter-ion adsorption by switching the dominant charge storage mechanism to co-ion desorption.