UTILISATION DES RESEAUX DE NEURONES ARTIFICIELS DE TYPE RBF POUR LA MODELISATION DU REGIME NORMAL A POINT DE FONCTIONNEMENT VARIABLE D’UNE INSTALLATION INDUSTRIELLE

This work presents the development of a mathematical model based on stochastic artificial neural networks type RBF (Radial Basis Function) for modeling the normal mode at a variable point of functionning of an industrial installation. The studied industrial facility is a distillation column of methylcyclohexane (C6H11-CH3) from toluene-methylcyclohexane mixture (C6H5-CH3 / C6H11-CH3) which was defined in the mass composition by 23% in methylcyclohexane. Neuronal architecture proposed for the modeling of this system consists of an input layer containing seven neurons, a hidden layer containing nine neurons and an output layer having a single neuron. The hidden layer is activated by a Gaussian function whose center is determined by using the K-means algorithm; however the output layer is activated by a linear function. Regarding existing weight between the hidden layer and the output layer, they are determined by the back-propagation algorithm of the error gradient. The RBF neural architecture type so determined was validated on a new database and has achieved better results compared to conventional methods

Calcul De L’indice De Qualité De L’eau (IQE) Pour L’évaluation De La Qualité Physico-Chimique Des Eaux Superficielles De L’Oued Moulouya (NE, Maroc)

L’indice de qualité de l'eau (IQE) est une expression numérique utilisée pour évaluer la qualité globale de l'eau à partir d’une grande quantité de données et il est facilement compris par les gestionnaires et décideurs. Dans cette étude, l’IQE à neuf paramètres physico-chimiques(pH, T°C, CE, O_diss, NH4, NO3, SO4, PO4 et DBO5) est utilisé pour évaluer la qualité globale des eaux superficielles de l’Oued Moulouya dans le Nord Est du Maroc pendant la période de mars à aout 2014. Vingt-deux sites ont été étudiés depuis l’amont de l’oued dans le Haut Atlas jusqu’à l’embouchure en Méditerranée sur environ 600 km de long. En amont dans la Haute Moulouya, la qualité des eaux reste excellente sans grande variation saisonnière excepté les sites au niveau des communes urbaines de Boumia et de Zaida où la qualité est respectivement mauvaise (IQE de 65 à 74) et non potable (IQE de 388 à 584). Dans la Moyenne et Basse Moulouya, la qualité des eaux diminue (IQE de 18 à 335) en allant d’excellente à non potable pendant l’hiver et le printemps et de bonne à non potable pendant l’été (IQE de 23 à 451). La dégradation de la qualité des eaux au niveau des communes de Boumia, Zaida, Missour et Gercif peut être due aux activités agricoles et aux rejets des eaux usées urbaines de ces agglomérations situées le long de l’oued. De façon saisonnière, la qualité de l'eau diminue de l'hiver à l'été en relation avec les variations des débits. De ce fait, la priorité doit être donnée à la réduction de ces sources de pollution afin de protéger les ressources en eau et d'améliorer la qualité de l'eau dans le bassin versant. The Water Quality Index (WQI) is a numerical expression used to assess the overall water quality from a large amount of data and to be easily understood by managers and decision-makers. In this study, the WQI with nine physicochemical parameters (pH, T °C, CE, O_diss, NH4, NO3, SO4, PO4 and BOD5) was used to evaluate the overall quality of the surface waters of the Moulouya River in the northeastern of Morocco during the period from March to August 2014. Twenty-two sites were studied from upstream of the wadi in the High Atlas to the mouth in the Mediterranean Sea about 600 km long. Upstream in the Upper Moulouya, water quality remains excellent with little seasonal variation except in the urban communes of Boumia and Zaida where the quality is respectively poor (WQI from 65 to 74) to non-potable (WQI from 388 to 584). In the Middle and Lower Moulouya, the quality of water decreases (WQI from 18 to 335) and varies between excellent, good, bad and not drinkable during the winter and the spring and between good, bad and not drinkable during the summer (WQI from 23 to 451). The deterioration of water quality in the communes of Boumia, Zaida, Missour and Gercif is due to agricultural activities and discharges of urban wastewater from these agglomerations located along the wadi. Seasonally, water quality has decreased from winter to summer, probably in relation to flow variations. As such, priority should be given to reducing these sources of pollution in order to protect water resources and improve water quality in the watershed

Mechanical and physicochemical performances of reinforced unfired clay bricks with recycled Typha-fibers waste as a construction material additive

The aim of this study is to evaluate the suitability of recycled Typha-fibers waste as a construction material additive to unfired clay bricks. The novel approach of this paper is providing an alternative of damping Typha plants in landfills and waterways, by recycling these waste and putting them into good use as a construction material additive. Physicochemical and performance of prepared brick samples of clay plus recycled Typha-fibers waste additives, at multiple proportions (0%, 1%, 3%, 7%, 15% and 20%) by weight, are investigated according to the Moroccan testing standards in the building sector. A steady-state mixing technique with an electric stirrer, for 10 ​min and at 95 ​rpm, was adopted to ensure a homogenous distribution of the fibrous particles inside the clay matrix to produce homogenous mixtures. The used clay was found of type Illite with non-swelling characteristics and a dominant SiO2 content, 59.6%, following X-ray diffraction and fluorescence tests. The incorporation of high Typha-fibers’ waste additives produced more porous bricks; as 20% of additive content reflected the highest recorded porosity, of 14.95%, compared to reference samples, 1.14%. This prompted higher capillary water absorption coefficient with higher Typha-fibers waste proportions. A 55% increase in water absorption was observed with the incorporation of 20% additive content compared to reference samples; yet obtained capillary measurements were under the maximum permissible water absorption limit, according to Moroccan testing standards NM EN 772-11. In addition, bulk density measurements showed that prepared brick samples can be classified as lightweight structures, as their bulk density is lower than 1.75 ​g/cm3. Produced specimens were classified as Earth Blocks Class 4 (EB4), Earth Blocks Class 3 (EB3) and Earth Blocks Class 2 (EB2) according to their recorded compressive strength. It can be deduced that higher Typha-fiber additive content produced good functioning brick samples, following Moroccan and international testing standards, with a more porous and lightweight structures, higher water absorption ration and decreased compressive strength

Recycled wastewater treatment plant sludge as a construction material additive to ecological lightweight earth bricks

Sludge disposal has major drawbacks on the environment when damping wastewater treatment sludge in landfills and estuaries. In addition to financial drawbacks manifested by the poor sludge management due to the lack of valorization regulations or investments’ encouragement. This paper analyzes the mechanical, physicochemical, and thermal properties of earth bricks of unfired type thanks to their low energy demand and high energy savings’ potential. This enables promoting a cleaner production protocol in accordance to the Moroccan testing standards in the building sector. X-ray Diffraction and Fluorescence analysis of the earth and sludge deployed reflected a dominance in Quartz (SiO2) with a respective 59.6% and 28.37%. This affirms the high clayey composition in the used earth material. Various sludge additive percentages (0%, 1%, 3%, 7%, 15% and 20%) to earth material, by weight, are investigated. Higher sludge content in the brick samples’ matrix produced more porous specimens, up to 17%, compared to control samples, of 0% additive content, with 1.04% porosity level. This resulted in higher capillary water absorption coefficient 47.15 ​g/(cm2.min0.5) and lower compressive strength 3.95 ​MPa compared to reference values, of 0% additive, of 25.10 ​g/(cm2.min0.5) and 6.17 ​MPa, respectively. In addition, bulk density analysis classified produced brick samples as lightweight construction materials, following the Moroccan testing standards. This is due to specimens’ respective bulk density does not go beyond the 1.75 ​g/cm3 mark. Improvements in thermal performance were also recorded with 43% and 30% gains in thermal conductivity and specific heat capacity properties, respectively, compared to control samples. Moreover, the incorporation of sludge additive into the clayey earth matrix has shown a decrease in the mixtures’ pH level. This resulted in producing more porous brick samples with improved thermal properties and lower mechanical compressive strength due to deterioration

Artificial intelligence for supervised classification purposes: Case of the surface water quality in the Moulouya River, Morocco

From a management perspective, water quality is determined by the desired end use. Water intended for leisure, drinking water, and the habitat of aquatic organisms requires higher levels of purity. In contrast, the quality standards of water used for hydraulic energy production are much less important. The main objective of this work is focused on the development of an evaluation system dealing with supervised classification of the physicochemical quality of the water surface in the Moulouya River through the use of artificial intelligence. A graphical interface under Matlab 2015 is presented. The latter makes it possible to create a classification model based on artificial neural networks of the multilayer perceptron type (ANN-MLP). Several configurations were tested during this study. The configuration [9 8 3] retained gives a coefficient of determination close to the unit with a minimum error value during the test phase. This study highlights the capacity of the classification model based on artificial neural networks of the multilayer perceptron type (ANN-MLP) proposed for the supervised classification of the different water quality classes, determined by the calculation of the system for assessing the quality of surface water (SEQ-water) at the level of the Moulouya River catchment area, with an overall classification rate equal to 98.5% and a classification rate during the test phase equal to 100%

Viscoelastic Measurements of Clay Suspensions and their Relationship to Strength of Unfired Clay Bricks with Almond Husk Additive

Engineered unfired clay bricks are an ecological alternative to overcome conventional construction materials’ inconvenience. This work investigates the rheological behavior of organo-silica suspensions, made from almond husk waste and illite clay, in relation to the compressive strength of unfired clay bricks incorporating the same waste. Selected proportions by weight of almond husk are 2, 5, 10, and 20 wt.%. Results from the compressive strength test show an improvement, of 8.98% in bricks with 2 wt.% waste content compared to the control sample, thanks to an increase in friction and the fiber bridging mechanism. Then, a progressively decrease in strength is recorded with the addition of waste. The decrease in strength is reported to be the creation of pores in the matrix, and loss of cohesion. It is found that the storage modulus, on a logarithmic scale, follows inversely the same trend of the compressive strength in previously prepared bricks. The results from the strength test and rheological test are linearly correlated. Strong coefficients of determination are found; R2=0.9809 (with 40 wt.% water content) and R2=0.9206 (with 50 wt.% water content). The findings from this study demonstrate the possibility of assessment and prediction of unfired bricks’ strength using rheometry