Mohamed Mesbah - Academia.edu (original) (raw)

Papers by Mohamed Mesbah

Les grés cambriens du réservoir principal Ra (réservoir anisométrique) du gisement de Hassi Messa... more Les grés cambriens du réservoir principal Ra (réservoir anisométrique) du gisement de Hassi Messaoud présentent des variations granulométriques considérables allant du grain fin au très grossier. Ils montrent des changements verticaux de faciès à l'échelle du puits. La distribution de la fraction argileuse dans les grés et dans les niveaux silteux est anisotrope et complexe. A. DJADOUN, A. BOUDELLA, M. MESBAH ET MBK. DJEDDI En ce qui concerne l'évolution du volume d'argile en fonction de la profondeur à l'échelle du réservoir Ra, l'étude a été faite pour les trois niveaux de ce réservoir Ra, à partir des enregistrements de spectrométrie, de rayonnements γ-naturels et de litho densité (Boudella, 2004); il s'agit du Ra supérieur (D4), du Ra moyen (D3) et du Ra inférieur (constitué des drains D2, ID et D1). La variation du rapport Th/K (entre 2,71 et 88,27) indique une certaine complexité dans l'évolution des minéraux argileux. Mots clés-Grès-Cambrien-Hassi Messaoud-Réservoir anisométrique (Ra)-Argile-Litho densité-Abaque-Type-Carotte-Spectroscopie RX et drains.

Acta Geophysica, 2020

The aim of this research is to assess relatively new hybrid methods for changes points and trends... more The aim of this research is to assess relatively new hybrid methods for changes points and trends detection on rainfall series: Dynamic Programming Bayesian Change Point Approach (BA), Şen's innovative trend method (ITM) and its double (D-ITM) and triple (T-ITM) version using the multi-scale analysis of the discrete wavelet transform (DWT) as a coupling method. Three representatives rainfall stations of northern Algeria were analysed at annual scale during the period 1920-2011. Moreover, correlation and spectral analysis (CSA) was applied for periodicity analysis. The CSA indicates the dominance of interannual to multidecadal rainfall periodicity fluctuations (2-years, 5-years and 20-years) characterising long term structured processes. Moreover, an abrupt downward trend with significant probability was detected from the 1970s with a relatively wet period between the periods 1950-1970 and 2001-2011. The latter is observed in particular in the central and eastern stations, well-explained by the BA-DWT. The results showed that the comparison results from different modelling approaches found that the hybrid models (BA-DWT, ITM-DWT, D-ITM-DWT, T-ITM-DWT) often perform better than the conventional approach (BA, ITM, D-ITM, T-ITM), where the computation time is very reasonable. The analysis revealed that information stemming from discrete wavelet spectrums significantly increased the accuracy of the methods for detecting hidden change points and trends.

Due to its geographical location, Algeria is characterized by high spatiotemporal rainfall variab... more Due to its geographical location, Algeria is characterized by high spatiotemporal rainfall variability. In this study, data from 69 rain gauges located in representative humid, semiarid and arid Mediterranean basins in northeastern Algeria were analyzed from 1970–2007 on a monthly scale using continuous wavelet analysis and hierarchical cluster analysis with the aim of regionalizing the rainfall patterns. The analysis shows that northern Algeria (cluster #1), which has a humid climate, is dominated by periodic annual fluctuations in the 8–16-month band. This mode explains most of the total variance, with a contribution between 25 and 60%. In the cluster #2 and cluster #3 regions, the climate varies towards aridity (humid to arid from north to south), and the climate is dominated by long-term periodic phenomena characterizing multiannual fluctuations of 64–128 months to decadal periods greater than 128 months, which explains why the total cumulative contribution exceeds 50% of the to...

Advances in Sustainable and Environmental Hydrology, Hydrogeology, Hydrochemistry and Water Resources, 2019

In this paper, the time and frequency-based methods as cross wavelet (XWT) and wavelet coherence ... more In this paper, the time and frequency-based methods as cross wavelet (XWT) and wavelet coherence transform (WCT) are used to search the links between rainfall and runoff of the hydrogeological systems of the Sebaou river watershed (northern central Algeria). The analysis shows a discontinuity in the linearity between rainfall and discharge that could correspond to the dry periods, storage during floods and the capacitance of the aquifer to store reserves, with the exception of some significant amplifications in some time intervals. Furthermore, human activities such as the dam construction and the smuggling of sands and rocks of the Oued (Wadi) since the year 1998 have had a significant impact on rainfall-runoff relationship, the flows decrease and the changes in the flow regime, which is more pronounced with a rupture in the annual component of 256–512 day of WCT spectrum.

Natural Hazards, 2021

In this research, the spatiotemporal meteorological drought pattern was assessed in the Oued Seba... more In this research, the spatiotemporal meteorological drought pattern was assessed in the Oued Sebaou basin (northern central Algeria) based on data from 23 rain gauges from 1972 to 2010 analyzed at seasonal and annual scales using the standardized precipitation index (SPI). A geographic information system was used to determine the cartographic precipitation concentration index and modified Fourier index (MFI) as well as the drought and rainfall characteristics of the stations. The analysis revealed moderate precipitation concentrations for all stations in the basin, for which longitude explains approximately 60% of the variance. The MFI results show three main aggressiveness distributions: weak, moderate and strong, which are similar to the spatial distribution of rainfall. The results show a prolonged drought that began in the late 1980s. In addition, more than 50% of the stations were affected by moderate and severe dry events during the period from 1986 to 2001. The comparison of the SPI values among the decades indicates that more than 20% of the cases were dominated by wet conditions from 1972 to 1981 and from 2002 to 2010, with near-normal and -normal events exceeding 70%. During the 2002–2010 decade, extreme wet events occurred in 7% of the cases, while in the 1972–1981 decade, only 1.75% of the cases were of this type. These results can provide watershed managers with more information to understand past drought and improve future water resource management.

British Journal of Surgery, 2021

Background This study aimed to determine the impact of pulmonary complications on death after sur... more Background This study aimed to determine the impact of pulmonary complications on death after surgery both before and during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Methods This was a patient-level, comparative analysis of two, international prospective cohort studies: one before the pandemic (January–October 2019) and the second during the SARS-CoV-2 pandemic (local emergence of COVID-19 up to 19 April 2020). Both included patients undergoing elective resection of an intra-abdominal cancer with curative intent across five surgical oncology disciplines. Patient selection and rates of 30-day postoperative pulmonary complications were compared. The primary outcome was 30-day postoperative mortality. Mediation analysis using a natural-effects model was used to estimate the proportion of deaths during the pandemic attributable to SARS-CoV-2 infection. Results This study included 7402 patients from 50 countries; 3031 (40.9 per cent) underwent surgery be...

Arabian Journal of Geosciences, 2018

This paper is proposed for the investigation of possible relationships between the large-scale at... more This paper is proposed for the investigation of possible relationships between the large-scale atmospheric circulation phenomena such as the North Atlantic Oscillation (NAO), Southern Oscillation (SOI), Mediterranean Oscillation (MO), Western Mediterranean Oscillation (WeMO) and rainfall of Sebaou river watershed (Northern central Algeria), covering a period of 39 years at monthly scale. Several time and scale-based methods were used: correlation and spectral analysis (CSA), continuous wavelet transform (CWT), multiresolution wavelet analysis (MRWA), cross wavelet analysis (XWT), wavelet coherence transform (WCT) and cross multiresolution wavelet analysis (CMRWA). The rainfall analysis by CSA and CWT has been clearly demonstrating the dominance of 1 year and 1-3-year modes, which they explain 30 to 51% and 25 to 28% of the variance respectively. However, the indices have shown that inter-annual fluctuations up to long-term explain between 60 and 90%. CWT and MRWA indicated significant fluctuations materialising a dry period more marked between the 1980s and 1990s with strong trend towards drier conditions starting from the 1980s, explained by the decadal components D7 and the approximation A7. In addition to the annual component, the XWT spectrums reveal strong coefficients for the SOI between 1992-2005 and 1986-2000 for the modes of 5-10 years and higher than 10 years respectively and less intense for NAO. The WCT between NAO and rainfall indicated the most significant relationship for 1 year, 1-3 years and 3-5 years approximately from the early 1980s corresponding to the dry period. However, the SOI affects rainfall only locally and with significant values more or less localised in the timefrequency space between MO, WeMO and rainfall, but this influence could be significant for low-frequency events. CWMRA shows that the components of 5-10 years and higher than 10 years are the most effective to represent climate index-rainfall significant relationships, where change in Daubechies wavelet properties can improve the correlation across the scales. Furthermore, has indicated that the short-term processes dominate the relationship index-rainfall, which masks the long-term phenomena whose influence can sometimes be very distant. As such, the rainfall variability of the study area has shown fairly significant links, at least locally with large-scale atmospheric circulation phenomena. Keywords Rainfall. Atmospheric circulation phenomena. Time and scale-based methods. Cross wavelet analysis. Sebaou river. Algeria

Journal of Hydrology: Regional Studies, 2017

Environmental Earth Sciences, 2016

Oued-Souf City, located in the northwestern part of Algeria, has rapidly grown and been urbanized... more Oued-Souf City, located in the northwestern part of Algeria, has rapidly grown and been urbanized. The city and surrounding areas depend heavily on groundwater as a water source for drinking, as well as domestic, industrial, and agricultural uses. Comprehensively understanding the chemistry of the groundwater provides insight into the interaction of water with the environment and contributes to better overall resource management. The phreatic groundwaters are SO 4-Ca in character. These waters are hard with a high salinity, which poses a distinct danger for plants. Furthermore, major chemical elements in the water have concentrations above the values recommended by World Health Organization. The phreatic groundwaters display bacteriological germs in sampled waters, and high concentrations of nitrates were detected in the samples due to the absence of a formal sanitation network. In this work, stable and radioactive isotopes are used to understand the water origin of the phreatic groundwaters. The present isotopic study suggests that the groundwaters from the Oued-Souf phreatic aquifer are composed of two primary components, one from infiltrating recent rain waters and the other one from deep captive groundwaters. Herein, descriptive statistics, correlation matrices, and factor analyses were employed to understand the hydrochemistry of the groundwater in the phreatic aquifer in the Oued-Souf area. Keywords Phreatic aquifer Á Miopliocene aquifer Á Hydrochemistry Á Principal component analysis (PCA) Á Bacteriology Á Isotope Á Oued-Souf Á Algerian Sahara Unintentionally a co-author name was forgotten in the retracted paper.

$Research paper thumbnail of Caractérisation multifractale de la structure temporelle des précipitations et des débits journaliers en Algérie septentrionale$

Environmental Earth Sciences, 2009

Desalination and Water Treatment, 2013

Exceptional hydrological events represent one of the most important natural risks which are respo... more Exceptional hydrological events represent one of the most important natural risks which are responsible for the loss of human lives and material goods. During recent decades, many automated or computerized approaches have been implemented to model this process. However, the complexity of hydrological regimes requires the use of specific tools for dynamical and non-linear systems. In order to model the rainfall-runoff transformation, we propose the employment of an adaptive neural network-based fuzzy inference system to predict the flow at the outlet of Algerian coastal basins. The neural network-based fuzzy inference system can be considered as an unlooped neural network for which each layer is a component of a neuro-fuzzy system. The obtained results show that the performances of neuro-fuzzy models exceed those of neural network models and classical multiple linear regression models.

Arabian Journal of Geosciences, 2008

Phreatic aquifers present many serious problems for local public authorities, and they have done ... more Phreatic aquifers present many serious problems for local public authorities, and they have done so especially for the water resources managers in Oued-Souf, Algeria, since 1980. Recently, a perturbation in piezometric level was observed in Oued-Souf. The spatial distribution of piezometric level data was analyzed by applying geostatistical methods, which provide an indication of the uncertainty of the estimation using the computer software VARIOWIN 2.2. In this paper, the evolution of the piezometric level by referring to other research campaigns was studied. Campaigns were conducted from March 1993 to April 2002. In the beginning, elementary statistics has been carried out to understand the statistical distribution and performed an analysis of variance so that two campaigns could be chosen for comparison. Geostatistics for modeling and cartography were applied. The results show that piezometric levels admit power model that the direction of groundwater flow is from south to north and that, due to the return of irrigation water (there is no drainage system), water levels increase in places like Foulia (1.35 m), northwest of Oued-Souf (1.43 m), Kouinine (4.58 m), and Ouzitene (3.01 m). The water levels also decrease in places like Guemar, Dmitha, Rhamra, and Djeldida, from between −2 and −6 m, due to excessive pumping of groundwater.

2019 International Conference on Smart Applications, Communications and Networking (SmartNets), 2019

Modern Industrial Control Systems (ICS) are very important in our life as we use information and ... more Modern Industrial Control Systems (ICS) are very important in our life as we use information and communication technology (ICT) to manage, monitor and improve ICS usage. This continually exposes it to new threats due to the vulnerabilities and architectural weaknesses introduced by the extensive use of ICT. Different types of ICSs have common attacks in which these attacks are very sophisticated and have a great impact. This paper presents the results of our research on the impact of ICT attacks. Besides, it discusses how to protect ICS from attacks and policies/standards that each nation implements to protect its critical infrastructure.