Temperature Performance of Different Pervious Pavements: Rainwater Harvesting for Energy Recovery Purposes

Pervious pavements offer a solution for rainwater runoff treatment in urban areas, combining storm-water management with water reuse purposes when the sub-bases become rainwater reservoirs. Furthermore, the thermal behaviour research into these systems has demonstrated their contribution to palliating the urban heat island effect in the hottest season and to delaying freezing during the coldest season. Recent investigations related to pervious pavements and their sub-bases have enabled the use of these structures combined with Ground Source Heat Pumps (GSHP) in addition to the other well-known applications. The aim of this field study is to investigate the temperature response observations of the water stored in the sub-bases of different pervious pavements under specific conditions, in order to evaluate the possibility of introducing GSHP technology. The base and sub-base temperatures of different types of pervious pavements were monitored during one year and the results obtained show the differences in pervious pavements temperature compared to air temperature over the period of study; and demonstrate that the sub-base is less affected by the air temperature than the base, due to the insulating capacity of pervious pavements. On the other hand, water samples were taken from the different pervious pavement sub-bases in order to assess the water quality deterioration due to the temperatures reached in the sub-base, focused on investigating the presence of Legionella in this particular aquatic environment.     

Methodology for leakage isolation using pressure sensitivity analysis in water distribution networks

Leaks are present to some extent in all water-distribution systems. This paper proposes a leakage localisation method based on the pressure measurements and pressure sensitivity analysis of nodes in a network. The sensitivity analysis using analytical tools is not a trivial job in a real network because of the huge non-explicit non-linear systems of equations that describe its dynamics. Simulations of the network in the presence and the absence of leakage may provide an approximation of this sensitivity. This matrix is binarised using a threshold independent of the node. The binary matrix is assumed as a signature matrix for leakages. However, there is a trade-off between the resolution of the leakage isolation procedure and the number of available pressure sensors. In order to maximise the isolability with a reasonable number of sensors, an optimal sensor placement methodology, based on genetic algorithms, is also proposed. These methodologies have been applied to the Barcelona Network using PICCOLO simulator. The sensor placement and the leakage detection and localisation methodologies are applied to several district management areas (DMA) in simulation and in reality.     

Coated stainless steels evaluation for bipolar plates in PEM water electrolysis conditions

Proton exchange membrane water electrolysis (PEMWE) is a promising technology to be incorporated in the production of green hydrogen, but one of its limitation to market penetration is the cost of bipolar plates (BPP).Aiming to reduce the cost of PEMWE stack, different surface engineered coating systems based on CrN/TiN, Ti/TiN, Ti and TiN deposited by physical vapor deposition on SS 316L, SS 904L and SS 321 were tested, as potential cost effective solutions to be implemented on bipolar plates. A corrosion evaluation has been carried out in anodic PEMWE conditions in order to determine the best substrate/coating combination for bipolar plates. Ti/TiN multi-layered coating on SS 321 shown the best performance with ?0.02% weight loss, current at 2 V_SHE to 436 μA cm^?2 and ICR after corrosion test to 9.9 mΩ cm².     

Sliding-mode control of doubly-fed generator for optimum power curve tracking

Aiming to achieve superior tracking of a predefined optimum power curve, a simple standard sliding-mode controller (SMC) for the rotor-side converter feeding a doubly-fed induction generator (DFIG) is synthesised. Besides being robust against DFIG parameter variations, it is implementable on FPGA, and does not require PWM or SVM modulation. Results of real-time hardware-in-the-loop evaluation, obtained when running the proposed SMC together with an MRAS observer for sensorless control, are reported.     

Characterization of Smooth CdTe(111) Films by the Conventional Close-Spaced Sublimation Technique

Thin epitaxial CdTe films were grown on CdTe(111)B substrates by the close-spaced sublimation (CSS) technique and were characterized over a range of experimental parameters. The source temperature was varied between 480°C and 540°C, maintaining an average constant source–substrate temperature difference ΔT of ∼130°C. Helium was used as a carrier gas at pressures between 2 Torr and 10 Torr. Scanning electron microscopy (SEM) and x-ray diffraction (XRD) were used to analyze the film morphology and structure. Growth rates ranging from 1 μm/h to 4 μm/h were observed, based on profilometer thickness measurements. The addition of a pre-growth heat treatment step and post-growth annealing treatment resulted in smooth CdTe(111) films. An evolution in growth morphology was demonstrated with SEM images and film quality was confirmed with XRD.     

Design and performance of active coupler for plastic optical fibres

A simple and successful design of a new active coupler for plastic optical fibres (POF) is presented. It consists of a 2×2 coupler with a polymer-dispersed liquid crystal (PDLC) film sandwiched in it, which takes advantage of the electrooptic effect of the PDLC. More than 3 dB of variation can be achieved by applying electric fields below 1.5 V/μm     

Preferential adsorption behaviour of several vinyl polymers in poly(ethylene glycol)(1)/THF(2)

Summary The preferential sorption coefficient in the ternary systems vinyl polymers (3)/Poly (ethylene glycol) (1)/THF(2) has been determined in dilute solutions by dialysis equilibrium differential refractometry at 633 nm and 298 K. A series of vinyl polymers of different side groups (Polystyrene, Poly (p-iodostyrene), Poly (n-vinyl carbazole), Poly (vinyl chloride) and Poly (methyl methacrylate)) has been studied.The results indicate that polymer side group play a fundamental role in the solvation behaviours of vinyl polymers. The characteristics of the polymer side group influences the kind and intensity of the polymer-binary solvent interactions and so, the rest of solution properties of these systems.     

Treatment of L-Fuzzy contexts with absent values

This work shows how to extract the missing information from an interval-valued L-Fuzzy context with some unknown values.Absent values are replaced using implications between attributes with high levels of support and confidence. Three kinds of implications are defined and analyzed for this purpose.We apply these results to an electrical network simulation, where the estimated relations between faulty power lines and voltage measurements can be compared with their real values.     

Barrier sensor based on plastic optical fiber to determine the windspeed at a wind generator

We have made use of the properties of plastic optical fibers (POFs) to develop a sensor for determining the wind speed in a wind generator. As POFs are easy to handle, flexible, economical, and immune to electromagnetic interference, we have utilized them to design an inexpensive sensor that is not affected by storms, which are one of the major problems in wind generators. Both theoretical and experimental results are presented. Specifically, we study the dynamic characteristics of the sensor by taking into account the light reflections on a mobile surface and by using two different theoretical approaches. The corresponding experimental results corroborate the validity of such approaches