Optimal sensor separation for AoA based localization via linear sensor array

This paper investigates the linear separation requirements for Angle-of-Arrival (AoA) sensors, in order to achieve the optimal performance in estimating the position of a target from multiple and typically noisy sensor measurements. We analyse the sensor-target geometry in terms of the Cramer-Rao inequality and the corresponding Fisher information matrix, in order to characterize localization performance with respect to the linear spacial distribution. Here we consider a situation where one sensor is fixed and the rest are free to be positioned in a linear array.

Identification of surface heterogeneity effects in cyclic voltammograms derived from analysis of an individually addressable gold array electrode

Voltammetric behavior at gold electrodes in aqueous media is known to be strongly dependent on electrode polishing and history. In this study, an electrode array consisting of 100 nominally identical and individually addressable gold disks electrodes, each with a radius of 127 µm, has been fabricated. The ability to analyze both individual electrode and total array performance enables microscopic aspects of the overall voltammetric response arising from variable levels of inhomogeneity in each electrode to be identified. The array configuration was initially employed with the reversible and hence relatively surface insensitive [Ru(NH₃)₆]^3+/2+ reaction and then with the more highly surface sensitive quasi-reversible [Fe(CN)₆]^3−/4− process. In both these cases, the reactants and products are solution soluble and, at a scan rate of 50 mV s⁻¹, each electrode in the array is assumed to behave independently, since no evidence of overlapping of the diffusion layers was detected. As would be expected, the variability of the individual electrodesʼ responses was significantly larger than found for the summed electrode behavior. In the case of cytochrome c voltammetry at a 4,4′-dipyridyl disulfide modified electrode, a far greater dependence on electrode history and electrode heterogeneity was detected. In this case, voltammograms derived from individual electrodes in the gold array electrode exhibit shape variations ranging from peak to sigmoidal. However, again the total response was always found to be well-defined. This voltammetry is consistent with a microscopic model of heterogeneity where some parts of each chemically modified electrode surface are electroactive while other parts are less active. The findings are consistent with the common existence of electrode heterogeneity in cyclic voltammetric responses at gold electrodes, that are normally difficult to detect, but fundamentally important, as electrode nonuniformity can give rise to subtle forms of kinetic and other forms of dispersion.

Inhibiting localized corrosion of aluminum and aluminum alloy by rare earth metal compounds : behaviors and characteristics observed using an electrochemically integrated multi-electrode array

An electrochemically integrated multi-electrode array namely the wire beam electrode (WBE) has been used to characterize the behavior of cerium chloride (CeCl3) and lanthanum chloride (LaCl3) in inhibiting localized corrosion of AA2024-T3 and AA1100. CeCl3 has been found to inhibit AA2024-T3 corrosion in 0.005 M sodium chloride (NaCl) solution by suppressing galvanic corrosion activities and by creating a large number of insignificant anodes. It has also been shown to inhibit localized corrosion of AA1100 in 0.5 M NaCl solution by promoting the random distribution of minor anodes. LaCl3 has been found to inhibit localized corrosion of AA2024-T3 at 1000 ppm, although its efficiency dropped significantly when its concentration decreased to 500 ppm. The addition of CeCl3 and LaCl3 to corrosion testing cells at later stages was unable to effectively suppress existing corrosion anodes.

Characterising localised corrosion inhibition by means of parameters measured by an electrochemically integrated multielectrode array

Electrochemical parameters including maximum anodic current density, total anodic current density, the number of anodic sites and the localised corrosion intensity index have been extracted from galvanic current distribution maps that were acquired using an electrochemically integrated multielectrode array, namely, the wire beam electrode. Experiments have been carried out to demonstrate the application of these new electrochemical parameters for characterising localised corrosion inhibition of metals. A typical corrosion inhibitor, potassium dichromate, was found to affect localised corrosion processes in various ways, for instance in sodium chloride solutions, it was found to inhibit localised corrosion of aluminium alloy AA 2024-T3 by suppressing galvanic corrosion activities occurring over the alloy surface, whereas it was found to control localised corrosion of AA 1100 by creating a large number of minor anodes distributing randomly over the metal surface.

Maximum power point tracking of partial shaded photovoltaic array using an evolutionary algorithm: a particle swarm optimization technique

 Partial shading is one of the unavoidable complications in the field of solar power generation. Although the most common approach in increasing a photovoltaic (PV) array’s efficiency has always been to introduce a bypass diode to the said array, this poses another problem in the form of multi-peaks curves whenever the modules are partially shaded. To further complicate matters, most conventional Maximum Power Point Tracking methods develop errors under certain circumstances (for example, they detect the local Maximum Power Point (MPP) instead of the global MPP) and reduce the efficiency of PV systems even further. Presently, much research has been undertaken to improve upon them. This study aims to employ an evolutionary algorithm technique, also known as particle swarm optimization, in MPP detection. VC 2014 Author(s).

Step by step analyzing, modeling and simulation of single and double array PV system in different environmental variability

This research analyses the mathematical model of the PV array with all the parameters involved, in the sequential steps. Then it is going to simulate the I-V and P-V characteristics of PV array in different climatology conditions, by using both MATLAB M-file and Simulink. Finally the capability of this method is demonstrated in simulated results, which are performed for both Single and Double Array PV system.

Cobalt carbonate hydroxide nanowire array on ti mesh: an efficient and robust 3D catalyst for on-demand hydrogen generation from alkaline naBH4 solution.

In this work, for the first time, a cobalt carbonate hydroxide (Co(CO3 )0.5 (OH)⋅0.11 H2 O) nanowire array on Ti mesh (CHNA/Ti) was applied to drive the dehydrogenation of alkaline NaBH4 solution for on-demand hydrogen production. Compared with other nanostructured Co-based catalyst systems, CHNA/Ti can be activated more quickly and separated easily from fuel solutions. This self-supported cobalt salt nanowire array catalyst works as an efficient and robust 3D catalyst for the hydrolysis reaction of NaBH4 with a hydrogen generation rate of 4000 mL min(-1)  gCo (-1) and a low apparent activation energy of 39.78 kJ mol(-1) and offers an attractive system for on-demand hydrogen generation.