National Technical University of Athens

About: National Technical University of Athens is a education organization based out in Athens, Attiki, Greece. It is known for research contribution in the topics: Large Hadron Collider & Nonlinear system. The organization has 13445 authors who have published 31259 publications receiving 723504 citations. The organization is also known as: Athens Polytechnic & NTUA.

Wireless Sensor Network Design for Transmission Line Monitoring, Metering, and Controlling: Introducing Broadband over Power Lines-Enhanced Network Model (BPLeNM)

Abstract: This paper introduces the broadband over power lines-enhanced network model (BPLeNM) that is suitable for efficiently delivering the generated data of wireless sensor networks (WSNs) of overhead high-voltage (HV) power grids to the substations. BPLeNM exploits the high data rates of the already installed BPL networks across overhead HV grids. BPLeNM is compared against other two well-verified network models from the relevant literature: the linear network model (LNM) and the optimal arrangement network model (OANM). The contribution of this paper is threefold. First, the general mathematical framework that is necessary for describing WSNs of overhead HV grids is first presented. In detail, the general mathematical formulation of BPLeNM is proposed while the existing formulations of LNM and OANM are extended so as to deal with the general case of overhead HV grids. Based on these general mathematical formulations, the general expression of maximum delay time of the WSN data is determined for the three network models. Second, the three network models are studied and assessed for a plethora of case scenarios. Through these case scenarios, the impact of different lengths of overhead HV grids, different network arrangements, new communications technologies, variation of WSN density across overhead HV grids, and changes of generated WSN data rate on the maximum delay time is thoroughly examined. Third, to assess the performance and the feasibility of the previous network models, the feasibility probability (FP) is proposed. FP is a macroscopic metric that estimates how much practical and economically feasible is the selection of one of the previous three network models. The main conclusion of this paper is that BPLeNM defines a powerful, convenient, and schedulable network model for today’s and future’s overhead HV grids in the smart grid (SG) landscape.

Plasma Micro-Nanotextured, Scratch, Water and Hexadecane Resistant, Superhydrophobic, and Superamphiphobic Polymeric Surfaces with Perfluorinated Monolayers

Abstract: Superhydrophobic and superamphiphobic toward superoleophobic polymeric surfaces of polymethyl methacrylate (PMMA), polyether ether ketone (PEEK), and polydimethyl siloxane (PDMS) are fabricated in a two-step process: (1) plasma texturing (i.e., ion-enhanced plasma etching with simultaneous roughening), with varying plasma chemistry depending on the polymer, and subsequently (2) grafting of self-assembled perfluorododecyltrichlorosilane monolayers (SAMs). Depending on the absence or not of an etch mask (i.e., colloidal microparticle self-assembly on it), random or ordered hierarchical micro-nanotexturing can be obtained. We demonstrate that stable organic monolayers can be grafted onto all these textured polymeric surfaces. After the monolayer deposition, the initially hydrophilic polymeric surfaces become superamphiphobic with static contact angles for water and oils >153°, for hexadecane >142°, and hysteresis <10° for all surfaces. This approach thus provides a simple and generic method to obtain superam...