Vortex phase diagram in BSCCO with damage tracks created by 30 MeV fullerene irradiation

Using 30 MeV C60 fullerene irradiation, we have produced latent tracks of diameter 20 nm and length 200 nm, near the surface of single crystalline BSCCO. A preliminary transmission electron microscopy study shows evidence for a very high density of deposited energy, and the ejection of material from the track core in very thin specimens. The latent tracks reveal themselves to be exceptionally strong pinning centers for vortices in the superconducting mixed state. Both the critical current density and magnetic irreversibility line are significantly enhanced. The irradiated crystals present salient features of the (B,T) phase diagram of vortex matter both of pristine crystals, such as the first order vortex phase transition, and the exponential Bose-glass line characteristic of heavy ion-irradiated crystals. We show that the latter is manifestly independent of the pinning potential.Comment: 10 pages, 13 figure

Priority Based Routing for Forest Fire Monitoring in Wireless Sensor Network

Recently, forest fire monitoring system in wireless sensor networks has received much attention. The conventional scheme receives fire alert data quickly to inform about fire forest event. However, since two or more nodes may detect a fire, high priority fire detection data frequently collide. In this paper, a new forest fire monitoring system is proposed in order to reduce high priority fire detection data dropped rate, by specifying a high priority received data immediately after fire detection and just before the destruction by fire. Furthermore, the node only transmits high priority data to a node, which has a low possibility of destruction by fire for low end-to-end delay of high priority fire detection data. The simulation results show that proposed scheme can reduce high priority data dropped ratio and the end-to-end delay, and have less effect of wind direction compared with the conventional scheme

Dijkstra-Based Higher Capacity Route Selection Algorithm Using Bounded Length and State Change for Automobiles

In general, automobiles travel from the origin to the destination using a shortest route. However, the shortest route may not be a highest wireless connection-capacity route, because of availability of wireless services (base station and access points etc.) along the route. To the best of our knowledge, currently no algorithm exists for selecting a route that maximizes wireless connection-capacity, while keeping route length shortest and close to shortest. In this paper, we propose two modified version of Dijkstra route selection algorithms: one for selecting a maximum connection capacity shortest route, and the other is for discovering higher wireless connection-capacity routes; the length of the route could be larger than a shortest route, but no larger than predetermined bound. The second proposed algorithm exploits the state change of the intersection to broaden the search range of possible routes. Results from our extensive simulation for a Manhattan-street type grid network with the heterogeneous IEEE 802.11a wireless access, show that for a 50% increase in route length and 15 Access Points (APs), the proposed algorithm can increases wireless connection-capacity by 35.67% and 31.27% compared to the shortest and random route selection algorithms, respectively

A Novel Blockchain-Based Product Ownership Management System (POMS) for Anti-Counterfeits in the Post Supply Chain

For more than a decade now, radio frequency identification (RFID) technology has been quite effective in providing anti-counterfeits measures in the supply chain. However, the genuineness of RFID tags cannot be guaranteed in the post supply chain, since these tags can be rather easily cloned in the public space. In this paper, we propose a novel product ownership management system (POMS) of RFID-attached products for anti-counterfeits that can be used in the post supply chain. For this purpose, we leverage the idea of Bitcoin's blockchain that anyone can check the proof of possession of balance. With the proposed POMS, a customer can reject the purchase of counterfeits even with genuine RFID tag information, if the seller does not possess their ownership. We have implemented a proof-of-concept experimental system employing a blockchain-based decentralized application platform, Ethereum, and evaluated its cost performance. Results have shown that, typically, the cost of managing the ownership of a product with up to six transfers is less than U.S. 1. © 2013 IEEE

Direct evidence of the anisotropic structure of vortices interacting with columnar defects in high-temperature superconductors through the analysis of Lorentz images

Two types of Fresnel contrasts of superconducting vortices in a Lorentz micrograph, corresponding to pinned and unpinned vortices, were obtained by a newly developed 1 MV field-emission transmission electron microscope on a Bi2Sr2CaCu2O8+delta (Bi-2212) thin specimen containing tilted linear columnar defects introduced by heavy ion irradiation. The main features of the Fresnel contrasts could be consistently interpreted by assuming that the vortices are pinned along the tilted Columnar defects and by using a layered or an anisotropic model to calculate the phase shift of the electron wave. The confirmed validity of both models strongly indicates that superconducting vortices in high-critical temperature (high-T-c) layered materials have an anisotropic structure