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Open Journal of Civil Engineering 2020年第3期10卷 213-225页

作者： mouhamed lamine chérif Aidara Makhaly Ba Alan Carter UFR Sciences de l’Ingénieur Université de Thiès Thiès Sénégal Ecole de Technologie Supérieure (ETS) Director of Pavement Bituminous Materials Laboratory (LCMB) Montréal Canada

The most famous model known in prediction of dynamic modulus for asphalt concretes is the Witczak and Hirsh models. These models didn’t use the mineralogical and chemical properties of aggregates. Witczak models used the passing or refusal percentage to sieve diameters and Hirsh model used the volumetric analysis. All models developed until now considered that the aggregates were geotechnical conforming to standards. In this study the first mineralogical and chemical properties were considered through the percentage of silica in the rock source of aggregates and the electric aggregate particles charge zeta. Dynamic modulus values used for regression process are determined from complex modulus test on nine asphalt concretes mix designed with aggregate types (basalt of Diack, quartzite of Bakel and Limestone of Bandia). Between Twelve initial inputs, the statistical regression by exclusion process keeps only seven parameters as input for the model. The mineralogical model showed good accuracy with R2 equal to 0.09. The student test on the model parameters showed that all the parameters included in the model were meaningful with good p inferior to 0.05. The Fisher test on the model showed the same result. The analysis of the sensitivity of the mineralogical model to zeta potential showed that the dynamic modulus increases with the positive zeta-potentials and decrease

关键词： Dynamic Modulus Mineralogical Basalt of Diack Quartzite of Bakel Limestone of Bandia Zeta Potential Silica

Evaluation of Dynamic Modulus of HMA Sigmoidal Prediction Models and Optimization by Approach of U.S. Mesh Sieve by AFNOR and LC Mesh Sieve

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Open Journal of Civil Engineering 2020年第3期10卷 195-212页

Pavement design tools are not universal. Indeed, in the sizing of pavements in the USA, the prediction models used in the calculation of the dynamic modulus of HMA are not adapted to the characterization of the mineral skeleton of the HMA mix designed with the French method. This article aims to assess the predictive models of the dynamic modulus used in the mechanistic-empirical design for their use in the design of bituminous pavements, and to develop new predictive models taking into account the sieve series LC and AFNOR standards. A total of six types of mixtures were subjected to the determination of complex modulus testing by direct tensile-compression on cylindrical specimens (26-700 LC) over a temperature range (5) and frequency (5) data. Dynamic modulus prediction models |E*| are studied Witczak model 1999 and model Witczak 2006. These models do not take into account the AFNOR or LC mesh sieve, an approach was made in relation to the US mesh sieve to replace ρ200 (0.075 mm), ρ4 (4.76 mm), ρ38 (9.5 mm) and ρ34 (19 mm) respectively by the AFNOR mesh P0.08 (0.08 mm), <

关键词： Dynamic Modulus Mechanistic-Empirical Design US Sieve Mesh HMA AFNOR LC

Impact of Intrinsic Properties of Aggregate and Volumetric Properties of Hot Mixture Asphalt (HMA) in the Influence of the Resistance to Rutting

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Open Journal of Civil Engineering 2020年第3期10卷 187-194页

Several studies show that properties of Hot Mixture Asphalt (HMA) mix design materials, aggregate gradation and volumetric properties had an influence on their resistance to rutting. However, these properties do not impact in the same way this performance. For a given aggregate type, an infinity aggregate gradation type can be observed, and for each type of HMA several types of bituminous binder can be used. This article aims to measure the evolution of resistance to rutting according to the three main classes of National Cooperative Highway Research Program (NCHRP) aggregate gradation (dense-graded, fine-graded and coarse-graded). To this end, a study was conducted on the measurement of rutting resistance for eight bituminous mixtures manufactured with two bitumen types and two types of manufacturing aggregates. The results showed that there is a priority order of these different parameters on the influence of the resistance to rutting. This highlights a competition between the properties of aggregate and type of granular skeleton. Indeed, for the same type of aggregate, asphalt binder type first impacts resistance to rutting of the HMA followed by aggregate gradation, volumetric properties of the mix and finally by the angularity of the aggregates. However, this order cannot be fixed and can depend of the intensity of each parameter.

关键词： Aggregate Gradation HMA Rutting Basalt Quartzite

choice of an Advanced Rheological Model for Modeling the Viscoelastic Behavior of Hot Mixtures Asphalt (HMA) from Sénégal (West Africa)

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Open Journal of Civil Engineering 2015年第3期5卷 289-298页

作者： mouhamed lamine ché rif Aidara Makhaly Ba Alan Carter UFR Engineering sciences Thi&egrave s University Thi&egrave s S&eacute né gal School of Superior Technologies (ETS) Director of Pavement Bituminous Materials Laboratory (LCMB) Montreal Canada

The main purpose of this article is to choose among advanced rheological models used in the French rational design, one that best represents the viscoelastic behavior of asphalt mixtures mixed with aggregates of Senegal. The model chosen will be the basis for the development of computational tools for stress and strain for Senegal. However, the calibration of these models needs complex modulus test results. In opposition to mechanical models the complex modulus can directly characterize the viscoelastic behavior of bituminous materials. Here determination is performed in the laboratory by using several types of tests divided into two groups: homogeneous tests and non-homogeneous tests. The choice of model will be carried out by statistical analysis through the least squares method. To this end, a study was carried out to “Laboratory of Pavement and Bituminous Materials” (LCMB) with asphalt concrete mixed with aggregate from Senegal named basalt of Diack and quartzite of Bakel. In this study, the test used to measure the complex modulus is the Canadian test method LC 26-700 (Determination of the complex modulus by tension-compression). There mainly exist two viewing complex modulus planes for laboratory test results: the Cole and Cole plane and the Black space. The uniqueness of the data points in these two areas means that studied asphalt concretes are thermorheologically simple and that the principle of time-temperature superposition can be applied. This means that the master curve may be drawn and that the same modulus value can be obtained for different pairs (frequency-temperature). These master curves are fitted during the calibration process by the advanced rheological models. One of the most used software in the French rational design for the visualization of complex modulus test results and calibration of rheological models developed tools is named Visco-analysis. In this study, its use in interpreting the complex modulus test results and calibration models

关键词： Complex and Dynamic Modulus Viscoelastic Huet Huet-Sayegh 2S2D1P Visco-Analyse Sum of Squared Deviation

Impact of Non-Compliance of Exposure Classes in Reinforced Concrete Structures

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Open Journal of Civil Engineering 2023年第1期13卷 25-34页

作者： Serigne Touba Thiam mouhamed lamine chérif Aidara Alinté Diatta Graduate School of Sustainable Development and Society Iba Der Thiam University Thies Senegal Department of Geology Faculty of Science and Technology Cheikh Anta DIOP University of Dakar Dakar Senegal Pan-African Polytechnic Institute of Dakar Dakar Senegal

From the National Agency for the Organization and Construction of Infrastructures (ANOCI) program to the Emerging Senegal Plan (PSE), construction in Senegal has improved considerably. However, deficiencies remain in the specification of materials used mainly in hydraulic concrete. They are generally related to the specification of aggregates for alkali reactivity and the choice of exposure classes specified in NF EN 206-1. The purpose of this article is to study the incidence of non-compliance with exposure classes in reinforced concrete structures. To carry out this study, surveys were carried out at several sites (districts) in Dakar (Cité Avion, Touba Ouakam, Cité Asecna, Cité Batrain, Cité Comico, Cité Assemblée and Terme Sud) in order to collect information on the formulation and implementation methods used. The comparison of the various readings carried out made it possible to deduce conclusions and to give recommendations when using standard NF EN 206-1.

关键词： Common Exposure Classes Specific Exposure Classes Concrete Alkali-Reaction

Zeta Potential of Aggregate and Dynamic Modulus of HMA Estimation Using Aggregate Silica Content

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Open Journal of Civil Engineering 2023年第1期13卷 35-47页

作者： mouhamed lamine chérif Aidara Serigne Touba Thiam Alan Carter Department of Geology Faculty of Science and Technology Cheikh Anta DIOP University of Dakar Dakar Senegal Graduate School of Sustainable Development and Society Iba Der Thiam University Thies Senegal Ecole de Technologie Supérieure de Montréal Montréal Canada

The mineralogical composition of an aggregate influences its adhesion with bitumen and therefore its dynamic modulus. However, few studies have been conducted on this aspect. One of the most used properties to describe the impact of aggregate on the adhesiveness phenomena is the zeta potential. In this study, the first mineralogical and chemical properties were considered through the percentage of silica in the rock source of aggregates and the electric aggregate particles charge zeta. Dynamic modulus values used for regression process are determined from complex modulus test on nine asphalt concretes mix designed with aggregate types (basalt of Diack, quartzite of Bakel and Limestone of Bandia). The results showed that aggregate with high percentage of silica have higher zeta potential than aggregate with low percentage of silica. The development of a zeta potential predictive model showed a strong sensitivity to silica. The results of the complex modulus tests showed that Hot Mixture Asphalt (HMA) mixed with aggregate containing high silica contents gave better results than those mixed with aggregates containing low percentage of silica. The dynamic modulus predictive models of HMA developed shows that it is the properties of bitumen that influence more. However, the effect of silica although low, is very marked at low temperatures and high frequencies.

关键词： Basalt of Diack Quartzite of Bakel Limestone of Bandia Complex Modulus Test Binder-Aggregate Adhesiveness

Late Diagnosis of Congenital Optic Disc Abnormalities

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Open Journal of Ophthalmology 2024年第3期14卷 229-235页

作者： Aïssatou Aw Soda Mbaye Jean Pierre Diagne Sy El Hadji Malick Alassane Ba Aly Mbara Ka Serigne Sohibou Gaye Ousmane Ndiaga Senghor lamine Ndiaye mouhamed Ndiaye El Hadj Abdellahi Seyid Papa Amadou Ndiaye Ophthalmology Department of Abass NDAO Hospital Cheikh Anta Diop University Dakar Senegal

Purpose: To show epidemiological and imaging aspects of congenital optic disc abnormalities diagnosed late. Method: It was a retrospective study, including all patients with congenital optic disc abnormalities diagnosed at a late age between January 2020 and October 2022 at the eye center of Abass Ndao Hospital. Complete ophthalmological examination was performed with eye imaging according to the cases. Results: 09 patients (10 eyes) were diagnosed with congenital optic disc abnormalities. The mean age was 29 years, with a sex ratio of 0.8. Three patients had consulted for unilateral decreased visual acuity since childhood, two for sudden vision loss and in four cases the diagnosis was fortuitous. Visual acuity was ranged from 1/200 to 20/20. Fundus examination showed myelinated retinal nerve fibers in four eyes, optic disc pit in three eyes including two complicated by maculopathy, two cases of morning glory syndrome and a case of pseudoduplication of the optic disc. Optical coherence tomography, ocular ultrasound B and OCT-Angiography were performed according to the cases. Conclusion: Congenital optic disc abnormalities are often diagnosed late. They are potentially amblyogenic and complications are not rare, worsening the visual prognosis. Their screening should be systematic by ophthalmological examination in newborns.

关键词： Myelinated Nerves Fibers Optic Disc Pit Morning Glory Syndrome Pseudoduplication Optic Disc

Evaluation of the Effect of Different Leaching Fractions on Soil Salinity

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Computational Water, Energy, and Environmental Engineering 2022年第4期11卷 116-133页

作者： Mapenda Ndiaye lamine Diop Aminata Sarr Yaye Deffa Wane Ibrahima Diatta Sidy mouhamed Seck Interdisciplinary Research Group in Support of Regional Planning and Local Development Gaston Berger University Saint-Louis Senegal Faculty of Agronomic Sciences Aquaculture and Food Technology Gaston Berger University Saint-Louis Senegal Laboratory of Biological Agronomic and Food Sciences and Modelling of Complex Systems (LABAAM) Saint-Louis Senegal

Soil salinisation is one of the main problems in agriculture. To overcome this problem, different methods of managing saline soils are used, including the practice of leaching under irrigation. The objective of this study is to evaluate the effect of different leaching fractions on saline soils in the Nguetiouro lowland in Gandiolais, in Senegal. For this purpose, a completely randomized block set-up has been implemented with three treatments, repeated three times: 1) T0 equivalent to a water volume input equal to the daily reference evapotranspiration (ETo), 2) T1 equivalent to a water volume input equal to the daily reference evapotranspiration plus 10% ETo of leaching and 3) T2 equivalent to a water volume input equal to the daily reference evapotranspiration of the medium plus 20% ETo of leaching. The results showed that leaching has an effect on soil salinity. The initial soil salt storage was reduced by 22.5%, 33.5%, and 50.6% in the first soil horizon, from 0 to 10 cm and by 14%, 35.3%, and 45% at depth from 10 to 30 cm for T0, T1, and T2, respectively. The fitting of simple linear regression models between electrical conductivity and soil moisture showed a negative linear relationship as a function of leaching fractions. The coefficients of determination of model are 0.74 for T0, 0.84 for T1 and 0.86 for T2 in the first soil horizon and 0.63 for T0, 0.83 for T1 and 0.88 for T2 in the depth form 10 to 30 cm. These results can be of great importance in the fight against soil salinity.

关键词： Leaching Salinity Evapotranspiration Gandiolais Senegal

Diagnosis of Male Hypogonadism: Experience of a Subsaharan African Endocrinology Department: Transversal Study from January 1^st, 2020 to July 31^st, 2022

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Open Journal of Endocrine and Metabolic Diseases 2023年第11期13卷 217-226页

作者： Nafy Ndiaye Ngone Diaba Diack Yakham Mohamed Leye mouhamed Mbar Niang Amadou lamine Cisse Yousra Benani Abdoulaye Leye Internal Medicine/Endocrinology-Diabetology Department Teaching Hospital of Pikine Cheikh Anta Diop University Dakar Senegal

Introduction: Hypogonadism should be suspected in a man who has symptoms and signs of testosterone deficiency. Clinical manifestations depend on the severity and duration of testosterone deficiency, whether the testicular deficit is concerning only androgen synthesis, spermatogenesis, or both. The objective of our study was to evaluate the clinical and aetiological characteristics of male hypogonadism in Dakar’s suburb. Patients and methods: We conducted a transversal study from January 1st, 2020 to July 31st, 2022. We included all male patients aged at least 14 years old with hypogonadism confirmed by a low level of early-morning free testosterone based on two different dosages. For all patients included, sociodemographic and diagnostic parameters were collected by using a pre-established registration form. Results: In total, 20 patients were selected. The average age was 36.3 years old [14 - 62 years old]. Half of the patients were overweight. Five patients had an abdominal circumference greater than 94 cm (37 inches). The other comorbidities found in our patients were type 2 diabetes (n = 1), hypertension (n = 1) and primary hypercholesterolemia in 2 patients. The functional signs reported by the patients were: couple’s infertility in 17 patients, decreased libido in 14 patients, erectile dysfunction in 13 patients, premature ejaculation in 2 patients and anejaculation in 4 patients. The physical examination revealed a bilateral testicular atrophy in 17 patients and a unilateral testicular atrophy in 2 patients;no patient had varicocele or urethral meatus abnormalities. Ten patients presented a micropenis. A eunuchoid morphotype was present in 6 patients and a short stature was noted in 2 patients. It was peripheral hypogonadism (HH) in 18 patients and hypogonadotropic hypogonadism (Hh) in 2 patients. The hypogonadotropic hypogonadism was isolated in both cases. The testicular echography confirmed testicular atrophy and showed cryptorchidism

关键词： Diagnostic Hypogonadism Male Senegal

Technical and Economic Feasibility of Solar Pump Irrigation in the North-Niayes Region in Senegal

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Engineering（科研） 2021年第7期13卷 399-419页

作者： Aminata Sarr lamine Diop Ibrahima Diatta Yaye Deffa Wane Ansouma Bodian Sidy mouhamed Seck Nicola Lamaddalena Luciano Mateos Faculty of Agronomic Sciences Aquaculture and Food Technology Gaston Berger University Sain Louis Senegal Irrigated Agriculture Mediterranean Agronomic Institute of Bari (CIHEAM BARI) Bari Italy Interdisciplinary Research Group in Support of Regional Planning and Local Development Gaston Berger University Sain Louis Senegal Faculty of Arts and Humanities Gaston Berger University Sain Louis Senegal Institute for Sustainable Agriculture CSIC Córdoba Spain

Northern Niayes is an area where agriculture is the main activity. Water used for irrigation in this area comes exclusively from groundwater. Farmers do not have access to electricity, thus fuel is the main source of energy used, which is very expensive. The objective of this study was to assess the techno-economic feasibility of solar irrigation pumps. Regarding technical feasibility, pump sizing was carried out on the basis of irrigation management, irrigation techniques, and water distribution. Also, the economic feasibility was studied on the basis of the Net Present Value, Benefit-Cost Ratio, Internal Rate of Return and Payback Period. Results showed for cultivated area ranging from 0.05 ha to 1.91 ha, pumps’ flow rate does not vary greatly from one irrigation technique to another. It varies between 2.5 m3/h and 31 m3/h. However, pressure and power are higher when using drip and sprinkler irrigation techniques, ranging from 27.8 m to 39.9 m for drip and 40.1 m to 58.5 m for sprinkler irrigation. The power varies between 0.05 kW and 1.6 kW for manual, between 0.05 kW and 2.5 kW for drip and between 0.1 kW and 4.75 kW for sprinkler irrigation. The investment cost is variable (669 euros to 21,400 euros), depending on the cultivated area, pump brands and characteristics, and irrigation techniques. Results show that the investment cost ranges from 669 euros (438,500 CFA) to 4090 euros (2,683,000 CFA) when using the manual irrigation technique, from 1281 euros to 20,600 euros when using the drip irrigation technique and from 819 euros to 21,403 eu

关键词： Irrigation Solar Feasibility Techno-Economic Niayes