Existence and numerical approximation of a solution to frictional contact problem for electro-elastic materials

In this paper,a frictional contact problem between an electro-elastic body and an electrically conductive foundation is studied.The contact is modeled by normal compliance with finite penetration and a version of Coulomb’s law of dry friction in which the coefficient of friction depends on the slip.In addition,the effects of the electrical conductivity of the foundation are taken into account.This model leads to a coupled system of the quasi-variational inequality of the elliptic type for the displacement and the nonlinear variational equation for the electric potential.The existence of a weak solution is proved by using an abstract result for elliptic variational inequalities and a fixed point argument.Then,a finite element approximation of the problem is presented.Under some regularity conditions,an optimal order error estimate of the approximate solution is derived.Finally,a successive iteration technique is used to solve the problem numerically and a convergence result is established.

Electro-Optical Model of Soiling Effects on Photovoltaic Panels and Performance Implications

In this paper,a detailed model of a photovoltaic(PV)panel is used to study the accumulation of dust on solar panels.The presence of dust diminishes the incident light intensity penetrating the panel’s cover glass,as it increases the reflection of light by particles.This phenomenon,commonly known as the“soiling effect”,presents a significant challenge to PV systems on a global scale.Two basic models of the equivalent circuits of a solar cell can be found,namely the single-diode model and the two-diode models.The limitation of efficiency data in manufacturers’datasheets has encouraged us to develop an equivalent electrical model that is efficient under dust conditions,integrated with optical transmittance considerations to investigate the soiling effect.The proposed approach is based on the use of experimental current-voltage(I-V)characteristics with simulated data using MATLAB/Simulink.Our research outcomes underscores the feasibility of accurately quantifying the reduction in energy production resulting from soiling by assessing the optical transmittance of accumulated dust on the surface of PV glass.

Numerical Modeling and Technico-Economic Analysis of a Hybrid Energy Production System for Self-Consumption: Case of Rural Area in the Comoros

This study aims to provide electricity to a remote village in the Union of Comoros that has been affected by energy problems for over 40 years. The study uses a 50 kW diesel generator, a 10 kW wind turbine, 1500 kW photovoltaic solar panels, a converter, and storage batteries as the proposed sources. The main objective of this study is to conduct a detailed analysis and optimization of a hybrid diesel and renewable energy system to meet the electricity demand of a remote area village of 800 to 1500 inhabitants located in the north of Ngazidja Island in Comoros. The study uses the Hybrid Optimization Model for Electric Renewable (HOMER) Pro to conduct simulations and optimize the analysis using meteorological data from Comoros. The results show that hybrid combination is more profitable in terms of margin on economic cost with a less expensive investment. With a diesel cost of $1/L, an average wind speed of 5.09 m/s and a solar irradiation value of 6.14 kWh/m2/day, the system works well with a proportion of renewable energy production of 99.44% with an emission quantity of 1311.407 kg/year. 99.2% of the production comes from renewable sources with an estimated energy surplus of 2,125,344 kWh/year with the cost of electricity (COE) estimated at $0.18/kWh, presenting a cost-effective alternative compared to current market rates. These results present better optimization of the used hybrid energy system, satisfying energy demand and reducing the environmental impact.

Structural and Physicochemical Properties of Dust and Their Effect on Solar Modules Efficiency in Agadir-Morocco

Experiments of soiling effects on the performances of a PV panel have been performed using dust collected from two sites in the region of Agadir-Morocco.The optical transmittance of the front glass was found to depend on the nature and density of dust.The nature of dust was studied by means of scanning electron microscopy and energy dispersive x-ray spectroscopy.It was found that the granulometry of dust particles depends on the study area.For a dust density of around 20 g/m^(2),the maximum power Pmax of the solar panel decreases drastically from 30 to 20 W for the(HP)site,and no more than 14 W for the(AD)site.The diversity of the behavior of the soiled panel was explained in terms of the size of the particles collected from each area.The transmission of light across the front glass of the PV panel is more affected when the sizes of particles are small.

Fabrication of branch-like Aph@LDH-MgO material through organic-inorganic hybrid conjugation for excellent anti-corrosion performance

Layered double hydroxides(LDH)frameworks have shown significant enhancement in stability and reusability,and their tailorable architecture brings new insight into the development of the next generation of hybrid materials,which attracted considerable attention in many fields over the years.One of the factors contributing to the widespread applicability of layered double hydroxides is their adaptable composition,which can accommodate a wide spectrum of potential anionic guests.This exceptional property makes the LDH system simple to adjust for various applications.However,most LDH systems are synthesized in situ in an autoclave at high temperatures and pressures that severely restrict the industrial use of such coating systems.In this study,LDH was directly synthesized on a magnesium alloy that had undergone plasma electrolytic oxidation(PEO)treatment in the presence of ethylenediaminetetraacetic acid,thereby avoiding the use of hydrothermal autoclave conditions.This LDH system was compared with a hybrid architecture consisting of organic-inorganic self-assembly.An organic layer was fabricated on top of the LDH film using 4-Aminophenol(Aph)compound,resulting in a smart hierarchical structure that can provide a robust Aph@LDH film with excellent anti-corrosion performance.At the molecular level,the conjugation characteristics and adsorption mechanism of Aph molecule were studied using two levels of theory as follows.First,Localized orbit locator(LOL)-πisosurface,electrostatic potential(ESP)distribution,and average local ionization energy(ALIE)on the molecular surface were used to highlight localization region,reveal the favorable electrophilic and nucleophilic attacks,and clearly explore the type of interactions that occurred around interesting regions.Second,first-principles based on density functional theory(DFT)was applied to study the hybrid mechanism of Aph on LDH system and elucidate their mutual interactions.The experimental and computational analyses suggest that the highπ-electron density and delocalization characteristics of the functional groups and benzene ring in the Aph molecule played a leading role in the synergistic effects arising from the combination of organic and inorganic coatings.This work provides a promising approach to design advanced hybrid materials with exceptional electrochemical performance.

An Efficient Hybrid Model for Arabic Text Recognition

In recent years,Deep Learning models have become indispensable in several fields such as computer vision,automatic object recognition,and automatic natural language processing.The implementation of a robust and efficient handwritten text recognition system remains a challenge for the research community in this field,especially for the Arabic language,which,compared to other languages,has a dearth of published works.In this work,we presented an efficient and new system for offline Arabic handwritten text recognition.Our new approach is based on the combination of a Convolutional Neural Network(CNN)and a Bidirectional Long-Term Memory(BLSTM)followed by a Connectionist Temporal Classification layer(CTC).Moreover,during the training phase of the model,we introduce an algorithm of data augmentation to increase the quality of data.Our proposed approach can recognize Arabic handwritten texts without the need to segment the characters,thus overcoming several problems related to this point.To train and test(evaluate)our approach,we used two Arabic handwritten text recognition databases,which are IFN/ENIT and KHATT.The Experimental results show that our new approach,compared to other methods in the literature,gives better results.

Prodigiosin from Serratia:Synthesis and potential applications

Prodigiosin is a red pigment with a pyrrolylpyrromethane skeleton.It is mainly produced by bacterial strains belonging to the Serratia genus,but also by some other genera,including Streptomyces and Vibrio.Within the genus Serratia,the pigment is generally produced as a virulence factor.However,it also has many important beneficial biological activities such as immunosuppressive and anti-proliferative activities.Moreover,the pigment has many industrial applications in textile and cosmetics.In this mini-review,we discuss the genetic and molecular mechanisms supporting prodigiosin synthesis and production from the Serratia genus,as well as its potential applications.

Opto-Structural Properties of Silicon Nitride Thin Films Deposited by ECR-PECVD

Amorphous hydrogenated silicon nitride thin films a-SiNx:H (abbreviated later by SiNx) were deposited by Electron Cyclotron Resonance plasma enhanced chemical vapor deposition method (ECR-PECVD). By changing ratio of gas flow (R = NH3/SiH4) in the reactor chamber different stoichiometric layers x = [N]/[Si] ([N] and [Si] atomic concentrations) are successfully deposited. Part of the obtained films has subsequently undergone rapid thermal annealing RTA (800°C/1 s) using halogen lamps. Optical and structural characterizations are then achieved by spectroscopic ellipsometry (SE), ion beam analysis and infrared absorption techniques. The SE measurements show that the tuning character of their refractive index n(λ) with stoichiometry x and their non-absorption properties in the range of 250 - 850 nm expect for Si-rich SiNx films in the ultraviolet UV range. The stoichiometry x and its depth profile are determined by Rutherford backscattering spectrometry (RBS) while the hydrogen profile (atomic concentration) is determined by Elastic Recoil Detection Analysis (ERDA). Vibrational characteristics of the Si-N, Si-H and N-H chemical bonds in the silicon nitride matrix are investigated by infrared absorption. An atomic hydrogen fraction ranging from 12% to 22% uniformly distributed as evaluated by ERDA is depending inversely on the stoichiometry x ranging from 0.34 to 1.46 as evaluated by RBS for the studied SiNx films. The hydrogen loss after RTA process and its out-diffusion depend strongly on the chemical structure of the films and less on the initial hydrogen concentration. A large hydrogen loss was noted for non-thermally stable Si-rich SiNx films. Rich nitrogen films are less sensitive to rapid thermal process.

SOLUTIONS AND STABILITY OF A GENERALIZATION OF WILSON'S EQUATION

In this paper we study the solutions and stability of the generalized Wilson＇s functional equation fc f（xty）dtt（t） ＋ fc f（xtσ（y））dtt（t） =2f（x）g（y）, x,y C G, where G is a locally compact group, a is a continuous involution of G and # is an idempotent complex measure with compact support and which is a-invariant. We show that ∫Gg（xty）dp（t） ＋ fcg（xta（y））dp（t） = 2g（x）g（y） if f = 0 and fcf（t.）dp（t） =0, where [fcf（t.）dp（t）]（x） = fc f（tx）dμ（t）. We also study some stability theorems of that equation and we establish the stability on noncommutative groups of the classical Wilson＇s functional equation f（xy） ＋ X（y）f（xa（y）） = 2f（x）g（y） x, y C G, where X is a unitary character of G.

APPROXIMATE SOLUTION OF P-RADICAL FUNCTIONAL EQUATION IN 2-BANACH SPACES

The aim of this paper is to introduce and solve the p-radical functional equation ■We also state an analogue of the fixed point theorem [12, Theorem 1] in 2-Banach spaces and investigate stability for this equation in 2-Banach spaces.

Study of the Inhibitor Scaling Effect of the Agricultural Water by a Phosphate Fertilizer

The localised irrigation or drop by drop system is a technique which makes it possible to save water, because it ensures a balanced and efficient distribution of water and an effective fertilization. However, this ferti-irrigation system is facing a number of problems hindering the agricultural development. The lack of uniformity of the localised irrigation was observed and found out that it is due to chemical clogging of drippers. Considering the complexity of the composition of the natural water used in micro-irrigation, we started our study by examining the effectiveness of the inhibitor on pure calco-carbonic water with 40°F, and then moved to explore the natural water of the agricultural region. The Legrand-Poirier-Leroy method allowed us to determine the position of the irrigation water compared to calco-carbonic balance. LCGE (abbreviation of “Laboratory of Chemistry and Environmental Engineering”) technique, based on the accelerated formation of calcium carbonate deposit under the effect of a degasification of studied water, enabled us to evaluate the scaling power of this water of irrigation either with or without inhibitor. The experimental results showed the following: in the case of pure calco-carbonic water with 40?F and of natural water, the addition respectively of 2 mg/L and 2.25 mg/L of phosphate fertilizer completely inhibits the precipitation of calcium carbonate under the conditions of the experiment.

Implementation of the Air Quality Monitoring Network at Agadir City in Morocco

Air pollution is a major global issue with widely known harmful effects on human health and the environment. This pollution is a very complex phenomenon given the diversity of pollutants that may be present in the atmosphere. The air quality in urban areas is of a great concern for residents living in cities and represents a current issue that requires an adequate management. So that air quality policy is driven by health concerns. In this paper, we present an overview on the experience of Agadir city to establish the air quality management policy, local authority on the whole have developed a good understanding of air quality in the area. Indeed for several years, efforts have been made to monitor the air quality in this city, this translated by air quality assessment since 2006 using mobile laboratory and fixed station. Our goals in this study were to review the operation of Local Air Quality Management (LAQM) making better use of available resources to improve its outcomes and make recommendations with a view to improving air quality issues. This work highlights the requirement to revise periodically the LAQM for generating priority for air quality issues within local authority and the need to implement the optimizing Air Quality Monitoring Network (AQMN).

Characterization and Classification of Rocks with Lamb Modes

The nondestructive investigation by ultrasound has become a fundamental tool for characterizing rocks. We applied this technique for characterizing samples of rocks. The later had been members of the following three big families of geogical classification: magmatic rocks, metamorphic rocks, sedimentary rocks. The method usually used is based on the measurement of ultrasound parameters, i.e. the longitudinal and transversal propagation velocities. The measurement of these parameters allows to determine the mechanical properties of each rock. These studies do not allow to find the three big axes of the rocks. In this work we show for each rock his corresponding ultrasonic signature by the use of his experimentally determined Lamb dispersion curves. The obtained results put in evidence that the descending slope of the Lamb modes is a reliable and efficient criterion for classifying rocks by ultrasound. This is an adequate solution for a good classification of rocks. It gives a high precision, it is reliable and quick and last not least cheap.

Medical Waste Management: A Case Study of the Souss-Massa-Drâa Region, Morocco

Medical waste management is of major concern due to the potentially high risks to both human health and the environment caused by inadequate waste management practices. In Morocco, as in many developing countries, little information is available regarding generation handling, and disposal of medical waste. The specific objective of this study was to analyse the medical waste management practices in the Souss-Massa-Draa region, Morocco. The study was carried out in seven of the twelve hospitals in the region, covering 66.2% of the bed capacity. A total of 219 healthcare personnel and their assistants were included: 35 doctors, 98 nurses, and 86 housekeepers. Site visits, interviews, and survey questionnaires were implemented to collect information regarding different medical waste management aspects, including medical waste generation, separation, collection, storage, transportation, and disposal. The results indicated that the medical waste generation rate ranged from 0.4 to 0.7 Kg/bed-day with a weighted average of 0.53 Kg/bed-day. The percentage of infectious and hazardous wastes in the total medical waste stream was about 30.5%. The remaining 69.5% was general wastes similar in properties to municipal wastes. Concerning waste separation, housekeepers demonstrate a slightly higher knowledge about waste separation, with 49.4% of correct answers, with nurses at 45.7%, and doctors the lowest value at 38.6%. The results about other management aspects indicated that practices in most surveyed hospitals did not comply with the principles stated in Moroccan legislation. Based on the findings, some measures are suggested to improve the present conditions and ensure that potential health and environmental risks of medical waste are minimized.

An Approximation Method for a Maximum Likelihood Equation System and Application to the Analysis of Accidents Data

There exist many iterative methods for computing the maximum likelihood estimator but most of them suffer from one or several drawbacks such as the need to inverse a Hessian matrix and the need to find good initial approximations of the parameters that are unknown in practice. In this paper, we present an estimation method without matrix inversion based on a linear approximation of the likelihood equations in a neighborhood of the constrained maximum likelihood estimator. We obtain closed-form approximations of solutions and standard errors. Then, we propose an iterative algorithm which cycles through the components of the vector parameter and updates one component at a time. The initial solution, which is necessary to start the iterative procedure, is automated. The proposed algorithm is compared to some of the best iterative optimization algorithms available on R and MATLAB software through a simulation study and applied to the statistical analysis of a road safety measure.

Role of Cell Surface Structures in Biofilm Formation by <i>Escherichia coli</i>

This study aims to understand the relationship between capabilities of Escherichia coli strains to form biofilm and serotype groups expressed on cell surface. Sixteen strains of E. coli were originally isolated from different food processing lines in different Moroccan cities. Strains serotyped based on their O (somatic), H (flagellar), and K (capsular) surface antigen profiles using different antiserums. Biofilm assays carried out in 96-well microtiter dishes using the method of O’Toole et al. Our results show that no clear relation observed between origin and serotype groups. In the other hand, we observed that not all studied strains were able to form biofilm. Furthermore, combination of antigens H40 and K11 appears to be involved in biofilm formation. In fact, the H antigen seems to be implicated in the placement of the bacterial cells near the surface and the K antigen may play a role in physicochemical interactions between bacteria and inert surface.

A Continuous Electronic Nose Odor Monitoring System in the City of Agadir Morocco

The city of Agadir is one of the best tourist destinations in Morocco, considered as one of the most beautiful bay in the world, which has a port infrastructure and strong industry based on the processing of seafood which often implicated as the source of odors. In order to identify in real time the sources responsible for the odors experienced in the city center and to act quickly in conjunction with industry, the Wilaya of Souss Massa Draa Region has implemented a continuous odor monitoring and tracking system using electronic noses. The treatment of meteorological data and data sent by electronic nose enables atmospheric dispersion modeling, which allows to follow instantly the odor level in the study area and to identify the sources responsible for odors with receiving warning of incidents odors, data analysis system generated every four minutes allowed to have results confirmed by companions of questionnaires to nearby residents. To reduce odors, recommendations have been suggested, which is to set up affordable and efficient practices.

Moroccan Domestic Tourism: Prioritization as an Inevitable Outcome of Coronavirus

Over the past two decades,Morocco has clearly banked on international tourists due to many reasons.But the current circumstances caused by the appearance of the Corona pandemic pushed the tourism players to re-prioritize the tourism market.Analysts in the sector predict a re-launch of international tourism in 2021 and a slow recovery of the tourism sector starts with reliance on domestic tourism to save tourism businesses from total crackdown.Due to many risk factors as a second wave of the virus,lockdown phobia,international travel restrictions,and economic recession that his different sectors all these hinder the revive of international tourism and prioritize the dynamic of domestic tourism.Our research is focused on the study of the probabilities of boosting the tourism sector by encouraging the local demand as a quick solution to overcome the current crisis.

Quantitative Adhesion of <i>Staphylococcus aureus</i>on Stainless Steel Coated with Milk

The surface energy characteristics of uncoated (clean) and coated stainless steel with UHT milk at various contact time (5 min, 30 min, 1 hours, 3 hours, 6 hours, 24 hours) were determined using contact angle measurement. Whatever the contact time, the clean stainless steel coupons became more hydrophobic and more electron acceptor when they are coated by milk. Inversely, the electron donor character seems to decreasing in this condition. The calculated surface energy component of coated stainless steel was found to vary with contact time. Its hydrophobicity and its electron acceptor were minimal after 3 hours of contact, but its electron donor was minimal after 1 hours of contact. Adhesion experiments of Staphylococcus aureus were carried out on uncoated and coated stainless steels at various contact times. For all contact times, the adhesion results show that milk reduce S. aureus adhesion, and the level of this reduction depend on contact time. This reduction was lower and higher after 1 hours, 5 min and 30 min of contact respectively.