Modelling and simulation of a water desalination station with solar multiple condensation evaporation cycle technique

This paper presents the study of a new generation of water desalination installation by solar energy using the SMCEC principle (Solar Multiple Condensation Evaporation Cycle). The good quality of distilled water obtained by this new concept favours its use for producing water for drinking and irrigation. The work presented in this paper includes modelling, simulation and experimental validation for this type of installation. The models of the different sections of the unit are developed from the governing heat and mass transfer equations. These models permit the sizing of the solar collectors, the evaporation tower and the condensation tower. The numeric simulation of the models allows the study of the relation among the different control parameters of the unit that would optimise its production. The obtained results are then compared against the experimental results.     

Flying Capacitor Multilevel Inverter Control Considering Lower Order Harmonics Elimination Based on Newton-Raphson Algorithm

Newton-Raphson-based flying capacitor multilevel inverter modeling is investigated for capacitor voltage balancing. Without using voltage feedback, Newton-Raphson method determines the best switching pattern for maintaining nil mean current in all capacitors, hence minimizing the capacitor voltage fluctuation and eliminating certain harmonic orders. Flying capacitor multilevel inverter (FCMI) modeling is developed to work with the selective harmonic elimination (SHE) technique to obtain a programmable pulse generator for multilevel inverter commutation cell control. Theoretical results are verified by experiments and simulations for a flying capacitor four-level inverter. Results show that the proposed method does effectively eliminate a number of specific low order harmonics, and the output voltage is resulted in low total harmonic distortion and with balanced flying capacitors.     

Development and application of an interface constitutive model for fully grouted rock-bolts and cable-bolts

This paper proposes a new interface constitutive model for fully grouted rock-bolts and cable-bolts based on pull-out test results.A database was created combining published experimental data with in-house tests.By means of a comprehensive framework,a Coulomb-type failure criterion accounting for friction mobilization was defined.During the elastic phase,in which the interface joint is not yet created,the proposed model provides zero radial displacement,and once the interface joint is created,interface dilatancy is modeled using a non-associated plastic potential inspired from the behavior of rock joints.The results predicted by the proposed model are in good agreement with experimental results.The model has been implemented in a finite element method(FEM) code and numerical simulations have been performed at the elementary and the structural scales.The results obtained provide confidence in the ability of the new model to assist in the design and optimization of bolting patterns.     

Crosscumulants based approaches for the structure identification of Volterra models

In this paper, we address the problem of structure identification of Volterra models. It consists in estimating the model order and the memory length of each kernel. Two methods based on input-output crosscumulants are developed. The first one uses zero mean independent and identically distributed Caussian input, and the second one concerns a symmetric input sequence. Simulations are performed on six models having different orders and kernel memory lengths to demonstrate the advantages of the proposed methods.     

An inexpensive and efficient method for the synthesis of BTO and STO at temperatures lower than 200 °C

During the past decade the reduction in size of functional architectures has been a dominating trend in many fields of science and technology. The search for electronic materials that can be cheaply solution-processed into nanopowders, while simultaneously providing quality device characteristics, represents a major challenge for material scientists. Solvothermal process is used in order to obtain fine nanoparticles of BaTiO₃ and SrTiO₃ at low temperatures by using an inorganic, ionic precursor. Rietveld refinement proves the presence of a mixture of 65% tetragonal and 35% cubic nanoparticles in the barium titanate powder with an average size of 73 nm and 67 nm, respectively. FTIR shows that an acid treatment allows the elimination of carbonate impurities.     

Preparation of Sb:SnO2 thin films and its effect on opto-electrical properties

The present study focuses on pure and antimony (Sb)-doped tin oxide thin film and its influence on their structural, optical, and electrical properties. Both undoped and Sb-doped SnO₂ thin films have been grown by using simple, inexpensive pyrolysis spray technique. The deposition temperature was optimized to 450 °C. X-ray diffractions pattern have revealed that the films are polycrystalline and have tetragonal rutile-type crystal structure. Undoped SnO₂ films grow along (110) preferred orientation, while the Sb-doped SnO₂ films grow along (200) direction. The size of Sb-doped tin oxide crystals changes from 26.3 to 58.0 nm when dopant concentration is changed from 5 to 25 wt%. The transmission spectra revealed that all the samples are transparent in the visible region, and the optical bandgap varies between 3.92 and 3.98 eV. SEM analysis shows that the surface morphology and grain size are affected by the doping rate. All the films exhibit a high transmittance in the visible region and show a sharp fundamental absorption edge at about 0.38–0.40 nm. The maximum electrical conductivity of 362.5 S/cm was obtained for the film doped with 5 wt% Sb. However, the carrier concentration is increased from 0.708?×?10¹⁸ to 4.058?×?10²⁰ cm³. The electrical study reveals that the films have n-type electrical conductivity and depend on Sb concentration. We observed a decrease in sheet resistance and resistivity with the increase in Sb dopant concentration. For the dopant concentration of 5 wt% of Sb in SnO₂, the Rs and ρ were found minimum with the values of 88.55 (Ω cm^?2) and 2.75 (Ω cm), respectively. We observed an increase in carrier concentration and a decrease in mobility with the addition of Sb up to 25 wt%. The highest figure of merit values 2.5?×?10^–3 Ω^?1 is obtained for the 5wt% Sb, which may be considered potential materials for solar cells' transparent windows.

     

An evidential fusion approach for activity recognition in ambient intelligence environments

With the growing emergence of ambient intelligence, ubiquitous computing, sensor networks and wireless networking technologies, “ubiquitous networked robotics” is becoming an active research domain of intelligent autonomous systems. It targets new innovative applications in which robotic systems will become part of these networks of artifacts to provide novel capabilities and various assistive services anywhere and anytime, such as healthcare and monitoring services for elderly in Ambient Assisted Living (AAL) environments. Situation recognition, in general, and activity recognition, in particular, provide an added value on the contextual information that can help the ubiquitous networked robot to autonomously provide the best service that meet the needs of the elderly. Dempster–Shafer theory of evidence and its derivatives are an efficient tool to handle uncertainty and incompleteness in smart homes and ubiquitous computing environments. However, their combination rules yield counter-intuitive results in high conflicting activities. In this paper, we propose a new approach to support conflict resolution in activity recognition in AAL environments. This approach is based on a new mapping for conflict evidential fusion to increase the efficiency and accuracy of activity recognition. It gives intuitive interpretation for combining multiple sources in all conflicting situations. The proposed approach, evaluated on a real world smart home dataset, achieves 78% of accuracy in activity recognition. The obtained results outperform those obtained with the existing combination rules.     

Waste factor evaluation using theoretical and experimental jean pants consumptions

This paper focuses on a contribution of modeling consumption of sewing thread during clothing jeans classic pants. In fact, to determine accurately the amount of sewed thread used by assembly type needs to model widely the amount of thread in each stitch type taking into consideration the waste factor contributions. Several factors determine the extent of thread consumption in any sewn garment, such as seam length, stitch density, seam types, and material thickness. Nevertheless, the variability of factors depends on the different styles of garment that let thread consumption of sewn product categories such as jean pants, shirts, and jacket to be variable. However, these factors are not constant with the different styles of garment. Hence, thread consumption is never a standard for sewn product categories such as trousers, jackets, shirts, products lingerie, and footwear. Regarding the linear regression method results, it may be concluded that waste factor is correlated accurately with the experimental sewing thread consumption. Our findings show that developed theoretical consumption equations give more accurate values compared to experimental ones. Likewise, taking account of waste factor in our theoretical analysis helps to obtain objectively the real sewing thread consumption value.     

A robust invariant bipolar representation for R 3 surfaces: applied to the face description

In this paper, we intend to introduce a novel invariant curved surface representation under the 3D motion group. It is constructed from the superposition of the two geodesic potentials generated from a given couple of surface points. By sampling this continuous representation, invariant points are extracted from a large neighborhood around these reference points. Different numerical methods are implemented in order to find an efficient approximation in the mean of the shape distance. The inference of small distortions of points positions applied to the reference points is analyzed. We apply the proposed representation to real 3D images. The experimentations are performed on the 3D facial database Bosphorus.