Papers by mohamed slimani
Meteorology and Atmospheric Physics, 2022
The main objectives of this paper are to get a better understand of the rainfall space-time varia... more The main objectives of this paper are to get a better understand of the rainfall space-time variability and to assess its rainfall tendency in the Merguellil basin, central Tunisia, by means of statistical tests. We assessed the rainfall at seasonal and monthly scales. Based on the availability of a continuous good record, eleven rain gauges were carefully chosen. Monthly rainfall data range from 1980 to 2016. Two tests are used to examine the trends: the non-parametric Mann–Kendall and Sen’s slope were selected to detect the existence, with a statistical significance, of an increase or a decrease in rainfall data trend. Results revealed high space-time variability of rainfall showing significant changes in seasonal and monthly rainfall amounts, for the studied period, particularly for summer months. The rise ranges from 0.68 mm/yr to 2.08 mm/yr and the highest values are observed in the basin upstream. Consequently, there are signs of a considerable rainfall raise in the basin. Increasing trends in summer, especially in July and August, were detected in the majority of studied rain gauges, where the monthly upward varies between 0.46 mm/yr and 0.83 mm/year. Most of the calculated slopes are statistically significant and the changes in Merguellil basin are more significant compared to other studies.
Hydrological Sciences Journal, 2022
ABSTRACT We are very grateful to the authors Aksoy and Cavus for their constructive contributions... more ABSTRACT We are very grateful to the authors Aksoy and Cavus for their constructive contributions to the discussion of our earlier paper “Drought assessment in a south Mediterranean transboundary catchment.” Our paper focused on the variability of rainfall and drought patterns in the Medjerda catchment in Tunisia and analysed the underlying causes resulting in these changes. Scope exists to improve the integration of the space–time variability in the drought assessment methodology. Different drought indices and statistical methods are employed in the study. The discussion of the article concentrates almost exclusively on the use of the Standardized Precipitation Index (SPI) and some mistyped equations. In this reply, we clarify the problematic points of misunderstanding and discuss the classification of droughts based on the SPI values.
Dans le present article, une modelisation energetique thermoelectrique d’un capteur hybride PV/T ... more Dans le present article, une modelisation energetique thermoelectrique d’un capteur hybride PV/T base sur l’utilisation d’un module photovoltaique du type amorphe QS60DGF a ete effectuee. Une etude de l’influence de divers parametres aerothermiques et physiques sur la performance energetique du capteur a ete menee, notamment l’effet de l’ajout d’une couverture vitree. Le modele de simulation numerique developpe nous a permis d’approcher aux resultats experimentaux releves de la litterature. Les resultats numeriques obtenus montrent l’efficacite energetique de ce type de capteur solaire et son utilite interessante comme un systeme energetique de cogeneration. Ces resultats revelent egalement l’importance de l’effet de certains parametres et des conditions de fonctionnement adoptees (temperature de ciel, temperature d'entree de l’air, temperatures des cellules PV, debit d’air, flux de rayonnement solaire incident) sur les performances des capteurs hybrides.
AIMS Materials Science, 2020
Sécheresse, 2012
Le present travail a pour objectif l’interpolation de l’evapotranspiration de reference (Eto evap... more Le present travail a pour objectif l’interpolation de l’evapotranspiration de reference (Eto evapotranspiration d’une surface de reference, bien alimentee en eau) par la methode de krigeage. Cette interpolation a ete precedee par une modelisation geostatistique de sa structure spatiale. Le variogramme ainsi trouve est lineaire avec un faible effet de pepite. En effet, l’Eto est relativement plus stable que d’autres grandeurs climatiques telles que la temperature, l’humidite, la duree d’ensoleillement et la vitesse du vent, qui presentent une variation spatiale beaucoup plus importante. Apres verification des parametres du variogramme par validation croisee, les champs de cartes d’Eto ont ete elabores par krigeage ordinaire. Sur ces cartes, deux gradients d’Eto se distinguent, un premier qui croit du nord vers le sud tunisien et un second qui decroit de l’interieur vers le littoral est du pays. Cela affirme l’influence preponderante du desert et de la mer Mediterranee sur l’intensite et la variation spatiale de ce parametre. Des cartes d’ecart type de krigeage ont ete ensuite deduites, montrant que l’incertitude d’interpolation varie de 5 a 10 % selon la region.
Journal of Hydrology, 2018
The coastal Chaouia, located on the Moroccan Atlantic coast, comports three aquifers: a first Pli... more The coastal Chaouia, located on the Moroccan Atlantic coast, comports three aquifers: a first Plioquaternary constitutes the cover, a second Cretaceous located at SW in the zone of Azemmour-Tnine Chtouka, and a third Primary located at SE in the zone of Tnine Chtouka-Casablanca. These reservoirs constitute the only exploitable water resource for the social and economic development of the region between Azemmour and Casablanca. These aquifers are unconfined, pellicular, and discontinuous. They feed by infiltration of rainwater and discharge at sea. Agricultural irrigation is carried out exclusively from the groundwater, which causes a drop of the piezometric surface and the intrusion of saltwater into the aquifer at the coast. The consequence is the abandonment of some wells contaminated by seawater leading to conflict situations and significant economic losses. Therefore, delineation of the freshwater/saltwater interface is very important in order to build a sustainable groundwater management system and to implement appropriate regulatory policies. The purpose of this study is to determine the extent and the geometric characteristics of the saltwater contamination extent in the coastal aquifers of the coastal Chaouia. To achieve this, 399 vertical electric soundings and 48 electrical resistivity tomography profiles were performed perpendicular to the ocean. Furthermore, the electrical conductivity and the piezometry were measured in 344 wells distributed over the study area. 4 The study demonstrated the effectiveness of electrical methods for mapping seawater intrusion into coastal aquifers. In fact, the results of the interpretation of the VES and ERTs after calibration with the lithological data of the boreholes, as well as the values of the electrical conductivity, have shown that the length of the saltwater wedge penetration inland depends on the lithological nature of the aquifer formations. Thus, in the zone of Azemmour-Tnine Chtouka, characterized by the presence of Cretaceous terrains, the extension of the saltwater wedge exceeds 2 km towards the continent and its depth reaches 45 m. On the other hand, in the zone of Tnine Chtouka-Casablanca, characterized by the rise of the schists surmounted by the altered schists the seawater intrusion remains limited at 700 m from the coast and at 20 m of depth.
Arabian Journal of Geosciences, 2018
Rainfall variability is an important feature of semiarid climates with major effects on hydrology... more Rainfall variability is an important feature of semiarid climates with major effects on hydrology, and beyond on key waterdependent societal aspects. Eventual changes in rainfall variability are a strong driver of change of hydrological processes, resources, and hazards, up to catchment signatures and spatial arrangements. We deal with observed precipitations and subsequent statistical coefficients available from a network of 15 rainfall gauges over and around the Merguellil catchment (1175 km 2), with series ranging up to the 1961-2013 period. We look for eventual annual trends and breakpoints with a set of methods: Mann Kendall test, Pettitt test, Hubert segmentation procedure, Buishand U statistic, and Lee Heghinian Bayesian procedure. The results underline oscillation of dry and wet periods; several studied rain gauges (Tella, Oueslatia forêt, Majbar, Kesra forêt, Henchir Bhima, and Haffouz DGRE) denote significant trends in annual precipitation. Some breaks are detected but they are not synchronous. These methods reveal the variability of rainfall regimes in the semiarid region and provide a synoptic view of detection and no-detection of symptoms of change. This work gives opportunities to water stakeholders and climate experts in understanding the relationships between climate variability and water availability.
Energy Conversion and Management, 2017
Abstract The thermal photovoltaic hybrid collector is a genuine cogeneration technology; it can p... more Abstract The thermal photovoltaic hybrid collector is a genuine cogeneration technology; it can produce electricity and heat simultaneously. In this paper, a comparative study is presented between four solar device configurations: photovoltaic module (PV-I), conventional hybrid solar air collector (PV/T-II), glazed hybrid solar air collector (PV/T-III) and glazed double-pass hybrid solar air collector (PV/T-IV). A numerical model is developed and validated through experimental results indicated in the previous literature. The numerical model takes the heat balance equations and different thermal and electrical parameters into account for each configuration included in this study, the energy performances are evaluated with a sample weather data of Algiers site. The numerical results show that the daily average of overall energy efficiency reaches: 29.63%, 51.02%, 69.47% and 74% for the first (PV-I), the second (PV/T-II), the third (PV/T-III) and the fourth (PV/T-IV) configurations respectively. These values are obtained with an air flow of 0.023 kg/s and introducing a sample of experimental weather data collected in Algiers site for a sunny day in summer.
Advances in Meteorology, 2016
Hydrology Research, 2016
Rainfall data are an essential input for many simulation models. In fact, these latter have a dec... more Rainfall data are an essential input for many simulation models. In fact, these latter have a decisive role in the development and application of rational water policies. Since the accuracy of the simulation depends strongly on the available data, the task of optimizing the monitoring network is of great importance. In this paper, an application is presented aiming at the evaluation of a precipitation monitoring network by predicting monthly, seasonal, and interannual average rainfall. The method given here is based on the theory of the regionalized variables using the well-known geostatistical variance reduction method. The procedure, which involves different analysis methods of the available data, such as estimation of the interpolation uncertainty and data cross validation, is applied to a case study data set in Tunisia in order to demonstrate the potential for improvement of the observation network quality. Root mean square error values are the criteria for evaluating rainfall e...
2015 6th International Conference on Modeling, Simulation, and Applied Optimization (ICMSAO), 2015
Tunisia presents a large spatio-temporal variability of rainfall which was largely observed in th... more Tunisia presents a large spatio-temporal variability of rainfall which was largely observed in the last years. This variability is influenced by several local and regional factors. The objective of this paper is to study the characteristics of the space and temporal variability of maximum daily rainfall in the state of Bizerte, located in the low valley of the medjerda basin and to seek the factors (topography, latitude, longitude, proximity of the sea, the speed direction of the wind …) who influence this variability to introduce them in the rainfall cartography. In order to study the space-time variability of the maximum daily rainfall, we used the frequential analyses, the principal component analysis (PCA) and the variography. Results show an important spatio-temporal variability caused by the effect of the several factors such as the topography, the depressions and the effect of the sea whose behavior of the rains differs from the South to the North of the state. These Observations are introduced into the cartography which is carried out by various methods of interpolation, the deterministic methods and geostatistics in aim to establish the maps of isohyets. Keywords—Space-time variability, maximum daily rainfall, frequential analyses, PCA, variography, medjerda basin.
The nutritive value and potential use of sun-dried common reed (Phragmites australis) leaves &quo... more The nutritive value and potential use of sun-dried common reed (Phragmites australis) leaves "CRL", for the growing rabbit was studied by comparing 3 diets (regression method) containing an increasing incorporation of CRL: 0% (control, CRL0), 15 % (CRL15) and 30% (CRL30) in substitution to the control diet (356 g NDF and 197 g CP/ kg). Three groups of 37 rabbits (individually caged) were fed ad libitum the three diets from weaning (35 d, mean weight: 722 ± 142 g) to 77 d of age. The faecal digestibility of the diets was measured between 42 and 46 days of age on 10 rabbits per group. Common reed leaves can be considered as a roughage since it contained 64% of NDF (38% of ADF) and 10.2% of crude protein. The digestible energy (DE) content of CRL calculated by regression was null (-1.8±0.29 MJ/kg as fed) that classed this roughage as a source of ballast, probably active for transit stimulation. The digestibility of crude protein reached 28.5%, corresponding to a digestible cr...
Proceedings of the International Association of Hydrological Sciences, 2015
Mediterranean Journal of Chemistry, 2013
Aziridines are known to undergo hydrolysis in the presence of cyclodextrins, whereas the latter a... more Aziridines are known to undergo hydrolysis in the presence of cyclodextrins, whereas the latter are largely investigated as potential vectors of biologically active compounds. Despite this easy cyclodextrininduced cleavage of aziridines in aqueous medium, it was of interest to find out a model aziridine derivative that would be sufficiently water-stable and form a stable complex with -cyclodextrin in aqueous medium, so that it could be used as a reference in future formulations or vectorization work. Among compounds we have investigated, we found out that only (S)-2-isopropyl-1-(o-nitrophenyl)sulfonyl)aziridine complied with the above-mentioned solubility and stability requirements. NMR studies of the inclusion complex of this derivative with -cyclodextrin provided useful parameters related to the stoichiometry of the complex and the association constant Ka. The geometry of the complex was assessed by 2D-ROESY experiments, suggesting a deep insertion of the aziridine into the cavity of -cyclodextrin.
Improvement of a geomorphology-based transfer function by integration of the rainfall variability... more Improvement of a geomorphology-based transfer function by integration of the rainfall variability through the development of a Matlab program
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Papers by mohamed slimani