Fault detection and identification for a class of continuous piecewise affine systems with unknown subsystems and partitions

This paper establishes a novel online fault detection and identification strategy for a class of continuous piecewise affine (PWA) systems, namely, bimodal and trimodal PWA systems. The main contributions with respect to the state‐of‐the‐art are the recursive nature of the proposed scheme and the consideration of parametric uncertainties in both partitions and in subsystems parameters. In order to handle this situation, we recast the continuous PWA into its max‐form representation and we exploit the recursive Newton‐Gauss algorithm on a suitable cost function to derive the adaptive laws to estimate online the unknown subsystem parameters, the partitions, and the loss in control authority for the PWA model. The effectiveness of the proposed methodology is verified via simulations applied to the benchmark example of a wheeled mobile robot.     

Embedded Metal Oxide Plasmonics Using Local Plasma Oxidation of AZO for Planar Metasurfaces

New methods for achieving high-quality conducting oxide metasurfaces are of great importance for a range of emerging applications from infrared thermal control coatings to epsilon-near-zero nonlinear optics. This work demonstrates the viability of plasma patterning as a technique to selectively and locally modulate the carrier density in planar Al-doped ZnO (AZO) metasurfaces without any associated topographical surface profile. This technique stands in strong contrast to conventional physical patterning which results in nonplanar textured surfaces. The approach can open up a new route to form novel photonic devices with planar metasurfaces, for example, antireflective coatings and multi-layer devices. To demonstrate the performance of the carrier-modulated AZO metasurfaces, two types of devices are realized using the demonstrated plasma patterning. A metasurface optical solar reflector is shown to produce infrared emissivity equivalent to a conventional etched design. Second, a multiband metasurface is achieved by integrating a Au visible-range metasurface on top of the planar AZO infrared metasurface. Independent control of spectral bands without significant cross-talk between infrared and visible functionalities is achieved. Local carrier tuning of conducting oxide films offers a conceptually new approach for oxide-based photonics and nanoelectronics and opens up new routes for integrated planar metasurfaces in optical technology.     

The Territorial Impact Assessment of transport: the case of the Egnatia motorway system in the cohesion potential of Southeast Europe

Territorial Impact Assessment (TIA) is proposed as a critical tool in order to investigate the way policies affect spatial development and hence territorial cohesion. The paper introduces a TIA methodological model in relation to transport sector. The design of the methodological model is based on a quantitative evaluation framework that comprises a set of selected indicators applied in a cross-border area of southeast Europe, influenced by the operation of the Greek motorway system of Egnatia and its vertical axes. The indicators are grouped into three main fields of TIA, i.e. transport intermodality, polycentric spatial organization and cross-border territorial cooperation. The TIA’s indicators are approximated by quantitative analysis. The procedure concludes to an overall composite indicator measuring the ‘level of territorial cohesion’ along with some core results and the expected added value. It also highlights some key technical aspects about the routines used and proceeds to suggestions for further refinement.     

Modeling and simulation of biphasic catalytic hydrogenation of a hydroformylated fuel

A model was developed based upon PR78 CEOS, Twu's alpha function and vdW mixing rules for simulating a pioneering chemical process of fuel upgrading. The chemical process of aqueous biphasic hydrogenation of a real hydroformylated fuel was experimentally conducted and simulated. The hydrogenation of the fuel occurred in aqueous media with in situ produced Ru-catalyst converting containing aldehydes to the corresponding alcohols. The above heterogenization of the homogeneous catalyst offered to the process an efficient and convenient way of catalyst recovery. The reaction temperature effect and the influence of hydrogen pressure in aqueous biphasic catalytic hydrogenation were examined. RuCl₃/TPPTS catalytic system proved to be an effective catalyst for fuel upgrading process, with the highest conversion of the aldehydes present in a hydroformylated fuel to reach 98.9% at 120 °C, 75 bar and at a short reaction time (2 h). A complete phase behavior of the fuel as well as a validation test of the simulation model were accomplished.     

Soil-washing design methodology for a lead-contaminated sandy-soil

Soils located near high traffic roadways, particularly where renovations have taken place, typically exhibit elevated levels of trace metals in the upper soil horizon. Regulators are currently seeking an efficient method of site characterization and treatment system design which will lend itself to timely and environmentally efficacious clean-up. The soil investigated in this study was a silty sand collected near a bridge abutment for a major interstate highway. The soil had a total lead content of 1392 mg/kg. In addition, the soil contained a considerable fraction of organic carbon (approximately 6.3%). A sequential chemical extraction indicated that a fraction of contaminants were in labile soil phases and thus amenable to chemical extraction (soil-washing). A soil washing design methodology is presented based on surface chemistry and equilibrium stage operation. In this work, a double layer surface complexation model was used to describe equilibrium sorption behavior and a preliminary design of an ex-situ counter-current equilibrium stage extraction process is presented. Model calibration was conducted using sorption data obtained from a 1:40 solid to liquid ratio (s/l), adsorption edge. Model validation was accomplished with batch titration data and a 1:20 s/l, adsorption edge. The model accurately predicted leachable lead concentrations over a wide pH range. The required number of ideal equilibrium stages was highly sensitive to pH.     

Effects of chromium (VI) addition on the activated sludge process

The effect of hexavalent chromium, Cr(VI), addition on various operating parameters of activated sludge process was evaluated. To accomplish this, two parallel lab-scale continuous-flow activated sludge plants were operated. One was used as a control plant, while the other received Cr(VI) concentrations equal to 0.5, 1, 3 and 5 mgl(-1). Cr(VI) concentrations of 0.5 mgl(-1) caused significant inhibition of the nitrification process (up to 74% decrease in ammonia removal efficiency). On the contrary, the effect of Cr(VI) on organic substrate removal was minor for concentrations up to 5 mgl(-1), indicating that heterotrophic microorganisms are less sensitive to Cr(VI) than nitrifiers. Activated sludge floc size and structure characterization showed that Cr(VI) concentrations higher than 1 mgl(-1) reduced the filaments abundance, causing the appearance of pin-point flocs and free-dispersed bacteria. Additionally, the variability of protozoa and rotifers was reduced. As a result of disperse growth, effluent quality deteriorated, since significant amounts of suspended solids escaped with the effluent. Termination of Cr(VI) addition led to a partial recovery of the nitrification process (up to 57% recovery). Similar recovery signs were not observed for activated sludge floc size and structure. Finally, shock loading to the control plant with 5 mgl(-1) Cr(VI) for 2 days resulted in a significant inhibition of the nitrification process and a reduction in filamentous microorganisms abundance.