Electrodeposition of lead dioxide on Fe electrode: application to the degradation of Indigo Carmine dye

Journal of Applied Electrochemistry - The modification of an iron electrode was carried out according to the following two steps. In a first step, a cathodic reduction is performed to form a film...     

Pilot contamination mitigation based on antenna subset transmission for mmWave massive MIMO

This paper tackles the problem of pilot contamination (PC) in mmWave Massive MIMO cellular systems. We propose an analog precoder based on antenna subset transmission technique to mitigate the PC. This technique ensures the interfering signal to become noise‐like signal thus helping a more efficient estimation of channel coefficients. Also, this strategy is low cost and introduces no complexity load. The result shows the effectiveness of the proposed precoder to mitigate PC issue.     

A Hybrid Bayesian Framework for Map Matching: Formulation Using Switching Kalman Filter

This paper addresses an important issue for intelligent transportation system, namely the ability of vehicles to safely and reliably localize themselves within an a priori known road map network. For this purpose, we propose an approach based on hybrid dynamic bayesian networks enabling to implement in a unified framework two of the most successful families of probabilistic model commonly used for localization: linear Kalman filters and Hidden Markov Models. The combination of these two models enables to manage and manipulate multi-hypotheses and multi-modality of observations characterizing Map Matching problems and it improves integrity approach. Another contribution of the paper is a chained-form state space representation of vehicle evolution which permits to deal with non-linearity of the used odometry model. Experimental results, using data from encoders’ sensors, a DGPS receiver and an accurate digital roadmap, illustrate the performance of this approach, especially in ambiguous situations.     

Comparative analysis of body composition assessment methods in healthy men and in chronic obstructive pulmonary disease patients: anthropometry, bioelectrical impedance and dual-energy X-ray absorptiometry

The aim of this study was to examine the agreement between the results of body fat (BF and BF%), fat-free mass (FFM) and FFM index (FFMI= FFM/height2) as estimated by skinfold anthropometry (ANT), bioelectrical impedance (BIA) and dual-energy X-ray absorptiometry (DXA) in two groups of men (> or = 50 y), one comprising healthy individuals (n=23) and the other, patients with chronic obstructive pulmonary disease (COPD) (n=24). Comparisons between body composition techniques were done by repeated measures ANOVA; the Bland & Altman procedure was used to analyse agreement. RESULTS AND CONCLUSIONS: 1) comparison between healthy and COPD groups showed significant differences between all studied variables; 2) in the healthy group, values for BF, BF%, FFM and FFMI were not significantly different when BIA or ANT was compared to DXA; however, in COPD, values for BF and BF% were significantly higher and for FFM and FFMI significantly lower when BIA was compared to DXA; in contrast, no differences were shown between values for these variables when ANT was compared with DXA; 3) Bland & Altman test, in both groups, showed no agreement between BIA and DXA and between ANT and DXA; it was also shown that body fat was overestimated and fat free mass underestimated by BIA in relation to DXA.     

Thermal analysis of a multistage active magnetic regenerator cycle for hydrogen liquefaction

The present paper deals with thermal analysis of cascade Active Magnetic Regenerator (AMR) cycle for the liquefaction of hydrogen starting from room temperature. For this purpose, the energy equations for fluid and solid within the regenerator bed of the AMR cycle have been considered. To solve the resulting mathematical model implicit finite difference method has been used. Thermal energy and mass balances are performed for several liquefaction systems composed of different number of cascade cycles. A simulation method using Hysys simulation commercial code has been presented. The multistage system operates with an ideal magnetic material as refrigerant and hydrogen gaseous as carrier fluid. First, the coefficient of performance (COP) of the AMR cycle and the required volume of magnetic material as functions of the number of cascades have been investigated. Then, the required volume is optimized by using the relationship between the COP and the volume. It has been found that a number of 6 AMR cycles operating in series is the optimal number of cascades required to liquefy 1 kg/h of hydrogen supplied at 25 °C. The system can operate between two volumes of magnetic material; namely, the minimum required volume (2.96 L) and the most efficient volume (7.44 L), corresponding to COP values of 1.23 and 4.7 respectively.     

Modelangelo: a subtractive 5-axis robotic arm for rapid prototyping

A PC-based, CAD-driven, 5-axis rapid prototyping (RP) robotic system that uses subtractive technology is presented. ModelAngelo, as it is called, consists of six integrated hardware and software subsystems. The system utilizes a virtual 3D CAD model to produce a set of commands used to control a 5-axis robotic setup to move the cutting tool, the tip of which is a heated wire, into a workpiece block (polystyrene foam or wax) to form complex-shaped objects.The user provides a 3D CAD model of the object to be sculpted. ModelAngelo_Software generates layered contoured slices at predetermined incremental steps. It builds up a data file that contains the corresponding cutting tool radial, angular, elevation and rotational positions of the modeled work. Then ModelAngelo_{PortMessenger} feeds the computer parallel port with consecutive commands that are read by ModelAngelo_Controller. Consequently, ModelAngelo_ReadNFeed performs the commands and sends feedback signals to the processor. The actuators then place the tool tip and the workpiece in their respective cutting positions via ModelAngelo_Mechanisms, which puts the model and the tip tool in the cutting position, where ModelAngelo_TipTool cutting-by-heat role starts.