The granites and pegmatites located in the southern part of the Issia region, near the columbo-tantaliferous placers, are characterized by the presence of rare metals such as beryl, lithium and Nb-Ta oxides. They main...The granites and pegmatites located in the southern part of the Issia region, near the columbo-tantaliferous placers, are characterized by the presence of rare metals such as beryl, lithium and Nb-Ta oxides. They mainly consist of micas, quartz, plagioclase and potassium feldspar. The work carried out on the micas of these granites and pegmatites (EPMA analyses) has provided new geochemical data contributing to the understanding of the magmatic evolution of the Issia granite complex. Mineralogically, the most evolved G3 granites are characterized by their abundance of muscovite compared to biotite and the presence of pegmatite veins. Geochemically, the muscovites of the G1 and G2 granites are more ferriferous than those of the G3 granites, however, the latter display higher Na contents than the G2 and G3. The muscovites of the granites show an evolution from the pure muscovite series to the zinnwaldite series (micas of the pegmatites) which are lithium-bearing micas. The mineralogical and chemical data of the micas show that they are S-type peraluminous granites and demonstrate the formation of granites and pegmatites through fractional crystallization of the same parental magma.展开更多
The aim of this study is to produce large quantities of yam tubers in the field from seed tubers derived from vitroplants regenerated from aerial stem cuttings and farmers’ tuber seeds. Seed tubers from ten yam culti...The aim of this study is to produce large quantities of yam tubers in the field from seed tubers derived from vitroplants regenerated from aerial stem cuttings and farmers’ tuber seeds. Seed tubers from ten yam cultivars, including five from Dioscorea alata (cDa083, cDa053, cDa115, cDa150 and cDa266) and five from Dioscorea cayenensis-rotundata (cDr015, cDr027, cDr150, cDr206 and cDr148) with distinct agro-morphological characteristics, were used as material. A completely randomized block design with 3 replications was used. In each block, all cultivars and seed types were represented. When put into cultivation, the tubers produced by the vitroplants all germinated and gave 100% healthy plants, compared with 86% to 100% healthy plants for the seed tubers produced by the farmers. Yields per hectare ranged from 10 to 25 tonnes for seed tubers produced by in vitro plants, and from 4 to 9 tons for seed tubers produced by farmers. Seed tubers from vitroplants can therefore be recommended to farmers as a solution to the problem of seed tuber unavailability.展开更多
Drinking good quality water is essential for better health. It is therefore essential to assess the radiological quality of all water consumed in the District of Abidjan in order to prevent related hazards. Thus, the ...Drinking good quality water is essential for better health. It is therefore essential to assess the radiological quality of all water consumed in the District of Abidjan in order to prevent related hazards. Thus, the objective of this study was to assess the risk of cancer due to the ingestion of alpha and beta emitting radionuclides in the different types of water consumed in the region. A total of 63 water samples with 43 tap water samples, 5 bottled mineral water and 15 sachet water samples was collected and taken to GAEC laboratory for analysis. The low background Gas-less Automatic Alpha/Beta counting system (Canberra iMatic<sup>TM</sup>) was used to determine alpha and beta activity concentrations. Activity concentrations of both gross alpha and gross beta obtained in water sample were respectively lower than the WHO recommended limits of 0.1 Bq/l and 1 Bq/l. Also, the annual effective dose and total equivalent effective dose found in mineral bottled water samples were higher than in other types of water. The assessment of radiological lifetime risk has shown values of cancer risk due to ingestion alpha and beta emitters lower than recommended limit. These results indicate that there is no health hazard associated to consumption of water in the District of Abidjan.展开更多
The present study was carried out on small-scale gold mining sites in the Yaouré region of Côte d’Ivoire. This region is geologically representative of the Birimian formations (2.1 Ga) of West Africa. The a...The present study was carried out on small-scale gold mining sites in the Yaouré region of Côte d’Ivoire. This region is geologically representative of the Birimian formations (2.1 Ga) of West Africa. The aim is to determine the potentially toxic trace metals (TMEs) generated by these sites, with a view to preventing possible contamination and/or metal pollution of the waters that provide fish products for local populations. To this end, a sampling campaign was carried out, resulting in the collection of 20 mining waste samples analyzed by X-ray fluorescence spectrometry (XRF) and 10 by X-ray diffractometer (XRD). The XRF analysis detected 06 predominant TMEs: arsenic, chromium, copper, nickel, zinc and vanadium. Statistical analysis was carried out to determine the distributions and correlations between these ETMs. To assess contamination and/or pollution levels, the following indices were calculated on the basis of reference concentrations of upper continental crust MTEs: Enrichment Factor, Geo-accumulation Index, Concentration Factor, Degree of contamination and those related to ecological risks. The results of statistical analyses and indices have shown that arsenic and chromium are the most predominant and can be, depending on the chemical form, potentially more toxic. The results of the DRX analysis show the occurrence of several minerals carrying these two MTEs, especially that of a rare mineral, Stenhuggarite, an arsenic oxide linked to hydrothermal veins. The majority of gold mining operations in West Africa are located in the birimian zone, hence the need for environmental monitoring by the relevant authorities, to prevent potential ecological risks to water and possibly health risks via the food chain.展开更多
The availability of groundwater of acceptable quality has become a difficult challenge to meet in many countries, particularly Côte d’Ivoire. The State of Côte d’Ivoire and rural populations are building h...The availability of groundwater of acceptable quality has become a difficult challenge to meet in many countries, particularly Côte d’Ivoire. The State of Côte d’Ivoire and rural populations are building hydraulic infrastructure for this purpose. However, the quality of water coming from these infrastructures remains to be determined. This study therefore aims to analyze certain physicochemical parameters of the groundwater of Gloazra, Kouezra and Trahonfla. These are temperature, pH, electrical conductivity, TDS, salinity level, hardness, alkalinity, chloride content and bicarbonate. To determine the pH, electrical conductivity, temperature, TDS, and salinity rate, an electrochemical analysis was carried out. The titrimetric analysis made it possible to determine the chloride and bicarbonate content, alkalinity, and hardness. The results indicate that the studied groundwater is soft and acidic with good mineralization. This water does not present a health hazard to consumers but can affect hydraulic equipment and household containers.展开更多
Data compression plays a key role in optimizing the use of memory storage space and also reducing latency in data transmission. In this paper, we are interested in lossless compression techniques because their perform...Data compression plays a key role in optimizing the use of memory storage space and also reducing latency in data transmission. In this paper, we are interested in lossless compression techniques because their performance is exploited with lossy compression techniques for images and videos generally using a mixed approach. To achieve our intended objective, which is to study the performance of lossless compression methods, we first carried out a literature review, a summary of which enabled us to select the most relevant, namely the following: arithmetic coding, LZW, Tunstall’s algorithm, RLE, BWT, Huffman coding and Shannon-Fano. Secondly, we designed a purposive text dataset with a repeating pattern in order to test the behavior and effectiveness of the selected compression techniques. Thirdly, we designed the compression algorithms and developed the programs (scripts) in Matlab in order to test their performance. Finally, following the tests conducted on relevant data that we constructed according to a deliberate model, the results show that these methods presented in order of performance are very satisfactory:- LZW- Arithmetic coding- Tunstall algorithm- BWT + RLELikewise, it appears that on the one hand, the performance of certain techniques relative to others is strongly linked to the sequencing and/or recurrence of symbols that make up the message, and on the other hand, to the cumulative time of encoding and decoding.展开更多
This study assesses the projected changes in the climate zoning of Côte d’Ivoire using the hierarchical classification of principal components (HCPC) method applied to the daily precipitation data of an ensemble...This study assesses the projected changes in the climate zoning of Côte d’Ivoire using the hierarchical classification of principal components (HCPC) method applied to the daily precipitation data of an ensemble of 14 CORDEX-AFRICA simulations under RCP4.5 and RCP8.5 scenarios. The results indicate the existence of three climate zones in Côte d’Ivoire (the coastal, the centre and the north) over the historical period (1981-2005). Moreover, CORDEX simulations project an extension of the surface area of drier climatic zones while a reduction of wetter zones, associated with the appearance of an intermediate climate zone with surface area varying from 77,560 km<sup>2</sup> to 134,960 km<sup>2</sup> depending on the period and the scenario. These results highlight the potential impacts of climate change on the delimitation of the climate zones of Côte d’Ivoire under the greenhouse gas emission scenarios. Thus, there is a reduction in the surface areas suitable for the production of cash crops such as cocoa and coffee. This could hinder the country’s economy and development, mainly based on these cash crops.展开更多
The West African Monsoon (WAM) is characterized by strong decadal and multi-decadal variability and the impacts can be catastrophic for the local populations. One of the factors put forward to explain this variability...The West African Monsoon (WAM) is characterized by strong decadal and multi-decadal variability and the impacts can be catastrophic for the local populations. One of the factors put forward to explain this variability involves the role of atmospheric dynamics, linked in particular to the Saharan Heat Low (SHL). This article addresses this question by comparing the sets of preindustrial control and historical simulation data from climate models carried out in the framework of the CMIP5 project and observations data over the 20<sup>th</sup> century. Through multivariate statistical analyses, it was established that decadal modes of ocean variability and decadal variability of Saharan atmospheric dynamics significantly influence decadal variability of monsoon precipitation. These results also suggest the existence of external anthropogenic forcing, which is superimposed on the decadal natural variability inducing an intensification of the signal in the historical simulations compared to preindustrial control simulations. We have also shown that decadal rainfall variability in the Sahel, once the influence of oceanic modes has been eliminated, appears to be driven mainly by the activity of the Arabian Heat Low (AHL) in the central Sahel, and by the structure of the meridional temperature gradient over the inter-tropical Atlantic in the western Sahel.展开更多
Chronic and potential non-healing wounds are a great challenge for patients, physicians, and wound care professionals and the health system. A balanced nutrition intake is essential for health as well as a speedy reco...Chronic and potential non-healing wounds are a great challenge for patients, physicians, and wound care professionals and the health system. A balanced nutrition intake is essential for health as well as a speedy recovery of such wounds. The study objective was to compare chronic wound inpatients supplemented with food nutrient content with outpatients with their usual intake in a cross-sectional study. Patients’ food samples were taken for chemical analyses. The protein, beta-carotene, sodium, magnesium, manganese, and potassium content prove statistically significant differences. Outpatients’ diets are more diversified than inpatients’ diets, and supplementation diet richest in beta-carotene and in protein. Outpatients have better dietary diversity than those who were hospitalized. The result provides insights of supplementary food as critical issues pertaining to chronic wounds management. However, analyzing bioavailability of nutrient on patients’ blood may provide more knowledge in the appropriate integrated wound management.展开更多
Background: Acute intoxications result from intentionally or accidentally taking a relatively significant amount of a chemical substance which triggers disturbances in the level of psychophysiological functions, the c...Background: Acute intoxications result from intentionally or accidentally taking a relatively significant amount of a chemical substance which triggers disturbances in the level of psychophysiological functions, the complications of which may lead to mental disorders, physical causalities, and death. Any acute intoxication mostly requires emergency care. Objective: To highlight the prevalence, history, clinical features, emergency treatment, and prediction of acute intoxication cases referred to the emergency services at the Provincial General Reference Hospital in Bukavu, DR-Congo. Methods: A retrospective cross-sectional study was conducted from January 2021 to October 2022 based on an analysis of patients’ medical files. Triage was performed among all-type of patient files recorded in the computerized hospital database Ebale-Sante to sort cases of intoxication. Results: During the observational period, 3966 emergency admissions were counted, of which 321 (8.09%) patients were identified as having acute intoxication. Among these, 100 files that containing sufficient information fit the quality criteria for this study’s analysis. The victims were infants, adolescents and adults aged 1 - 45 years, and 52% were female and 48% were male. Most cases were accidental and, occurred at home, and the victims were driven to the hospital within 2 - 24 hours. The substances consumed included household products, drugs, and herbs. Resuscitation care, antidotes and supportive symptomatic medications ensured that 85% were healed and 10% experienced sequelae;however, 5% died. Conclusion: Acute intoxication occurs in infants mostly accidentally though the ingestion of household products and medicines. Furthermore, suicide cases may occur in traumatized adolescents and discordant couples. People should be informed about how to store hazardous products (e.g.: drugs, household products and pesticides), which should not be available to children, to avoid unintentional poisoning. Special training in clinical toxicology is required to reduce treatment failure.展开更多
Background: Type II diabetes mellitus is associated with multiple metabolic derangements which can cause secondary pathophysiological changes in multiple organ systems. This in turn can impose a heavy burden of morbid...Background: Type II diabetes mellitus is associated with multiple metabolic derangements which can cause secondary pathophysiological changes in multiple organ systems. This in turn can impose a heavy burden of morbidity and mortality from micro‑ and macro‑vascular complications. This study aimed to describe the metabolic and therapeutic profile of a subgroup of type 2 diabetic patients who have treatment failure with oral anti-hyperglycemic agents with persistent hyperglycemia despite insulin treatment. Methods: 60 type 2 diabetic patients in treatment failure with oral antidiabetics and under insulin treatment, aged 35 to 70 years, were recruited at the Diabetes Clinic of the University Teaching Hospital of Treichville in Abidjan, Côte d’Ivoire. Blood samples were collected in tubes containing Ethylenediaminetetraacetic Acid (EDTA) to determine glycated hemoglobin (HbA1c). Results: The average age of the population was 54 ± 9.38 years with a sex ratio (M/F) of 0.3, an average BMI of 30.25 ± 5 kg/m<sup>2</sup>, and an average HbA1c of 10.1% ± 1.6% for an average diabetes duration of 11.8 ± 5.8 years. The average insulin dose was 74.556 ± 16.21 UI/day, and the average duration of insulin treatment was 5.4 ± 3.1 years. The average HbA1c value was 10.1% ± 1.87% in men against 10.03% ± 1.53% in women with no significant difference (p = 0.1). The mean HbA1c values according to patient weight were 10.08% ± 2.05% for normal weight, 9.55% ± 2.26% for overweight, and 10.57% for obese, with no significant difference between the three groups of patients (p = 0.1). Conclusion: This study showed a persistence increase in glycated hemoglobin regardless of the treatment regimen, duration, and dose of insulin treatment in the subpopulation of type 2 diabetic patients.展开更多
Sickle cell disease (SCD) is a genetic blood disorder that affects the shape and transportation of red blood cells (RBCs) in blood vessels, leading to various clinical complications. Sickle cell disease is a widesprea...Sickle cell disease (SCD) is a genetic blood disorder that affects the shape and transportation of red blood cells (RBCs) in blood vessels, leading to various clinical complications. Sickle cell disease is a widespread genetic disease in Black Africa. The objective of this study was to evaluate the sickling inhibition activity of Griffonia simplicifolia. Quantitative and qualitative tests were used to determine the major groups of secondary metabolites present in the Griffonia simplicifolia leaves extracts and the modified Emmel test was used to perform the study of sickling inhibition activity. The OECD 423 toxicity study showed that at a single dose of 2000 mg/kg bw, Griffonia simplicifolia leaves extracts are not toxic. All tested substances inhibit erythrocyte falciformation in a dose-dependent manner. The percentages of inhibition were 50.35%, 73% and 94.23% for aqueous extract, hydromethanolic extract and phenylalanine respectively at the concentration of 15 mg/mL. The methanolic extract (70%) had higher activity compared to the aqueous extract. These results suggest that the Griffonia simplicifolia extracts have some potential to be used as alternative antisickling therapy in SCD management.展开更多
This paper deals with the security of stock market transactions within financial markets, particularly that of the West African Economic and Monetary Union (UEMOA). The confidentiality and integrity of sensitive data ...This paper deals with the security of stock market transactions within financial markets, particularly that of the West African Economic and Monetary Union (UEMOA). The confidentiality and integrity of sensitive data in the stock market being crucial, the implementation of robust systems which guarantee trust between the different actors is essential. We therefore proposed, after analyzing the limits of several security approaches in the literature, an architecture based on blockchain technology making it possible to both identify and reduce the vulnerabilities linked to the design, implementation work or the use of web applications used for transactions. Our proposal makes it possible, thanks to two-factor authentication via the Blockchain, to strengthen the security of investors’ accounts and the automated recording of transactions in the Blockchain while guaranteeing the integrity of stock market operations. It also provides an application vulnerability report. To validate our approach, we compared our results to those of three other security tools, at the level of different metrics. Our approach achieved the best performance in each case.展开更多
Since 2015, Côte d’Ivoire has been the world’s largest cashew producer. However, cashew orchards in Côte d’Ivoire are infected by fungal diseases that weaken production. And the contribution of weeds to t...Since 2015, Côte d’Ivoire has been the world’s largest cashew producer. However, cashew orchards in Côte d’Ivoire are infected by fungal diseases that weaken production. And the contribution of weeds to the spread of these diseases is not yet understood. This study was initiated with the aim of establishing the role of weeds in the proliferation of pathogenic fungi in orchards. It consisted of a survey of weeds showing disease symptoms in cashew orchards in Côte d’Ivoire from February 2021 to July 2022. The itinerant method was used for the weed inventory. Symptomatic leaves were collected and sent to the laboratory for diagnosis on PDA (Potatoes Dextrose Agar) medium. In total, 50 species in 46 genera and 23 families were recorded. Laboratory diagnosis of the samples showed that 80% of the weeds identified harboured pathogenic fungi. The highest infection rates were obtained on Danielia oliveri R. (99.33% to 100%), Vitellaria paradoxa G. (100%), Pterocarpus erinaceus P. (83.91% to 99.33%), Micuna pruriens L. (98.33% to 100%) and Isoberlinia doka C. et S. (56.33% to 100%). The diagnosis revealed the presence of Lasiodiplodia sp, Colletotrichum sp, Pestalotia sp, Alternaria sp and Curvularia sp on weeds in the cashew orchard in Côte d’Ivoire.展开更多
Introduction: Abnormalities in mineral and bone metabolism, particularly phosphocalcic metabolism, are common in renal failure and are associated with a significant morbidity and mortality. The regulation of phosphoca...Introduction: Abnormalities in mineral and bone metabolism, particularly phosphocalcic metabolism, are common in renal failure and are associated with a significant morbidity and mortality. The regulation of phosphocalcic metabolism is subject to a particularly precise and complex control of parathormone (PTH) and vitamin D. Assessment of vitamin D and parathyroid hormone concentrations would help to improve the medical management of patients with chronic kidney disease and ensure a better quality of life. Methods: The study population consisted of 138 individuals including 46 non- dialysis renal failure patients, 46 chronic hemodialysis patients and 46 non- renal failure volunteers to serve as controls. Serum Parathyroid hormone and Vitamin D concentrations were measured using the Vidas automated system. Results: 25-hydroxyvitamin D concentrations in controls (65 ± 2.41 nmol/L) and dialysis patients (70 ± 3.03 nmol/L) were significantly higher than those in CKD patients (48 ± 3.34 nmol/L). On the other hand, the mean values of Parathyroid hormone in dialysis patients (312 ± 36.22 pg/mL) and CKD patients (117 ± 10.68 pg/mL) were very high compared to that in controls (25 ± 2.34 pg/mL). Conclusion: Secondary hyperparathyroidism is common in renal failure. Parathyroid hormone and 25-hydroxyvitamin D assays would be adequate for better management of chronic renal failure.展开更多
Introduction: The study of mortality is an indicator that allows a control and a review of the therapeutic measures in the hospital environment. The purpose of this work was to determine the epidemiological profile of...Introduction: The study of mortality is an indicator that allows a control and a review of the therapeutic measures in the hospital environment. The purpose of this work was to determine the epidemiological profile of the patients who died and analyse the circumstances of the death in a hospital service. Material and Methods: It is a retrospective descriptive study conducted in the service of Stomatology, maxillofacial and plastic surgery of the face over a period of 10 years (from January 1999 to December 2008). Seventy-two cases have been taken into account. Results: The crude death rate was 4.29%. Higher level of male has been noted with a sex ratio of 1.77. The most affected age groups were the 3rd and 2nd decades, respectively with 20.8% and 19.4% with an average age of 39 years. Cellulitis of the face and their complications were responsible for deaths in 58.33% of cases. The majority of deaths occurred between 6 p.m. and 6 a.m. (65.28%). These deaths were preventable in 5.6% of cases. Conclusion: Facing the lack of description of the ultimate circumstances of death in the medical records, the conclusion of this study has been the establishment of a regular medical audit in the service, which would track mortality in order to reduce its rate.展开更多
<span style="line-height:1.5;">Natural plant products have been used by the population of the south-eastern part of C</span><span lang="EN-US" style="line-height:1.5;">&...<span style="line-height:1.5;">Natural plant products have been used by the population of the south-eastern part of C</span><span lang="EN-US" style="line-height:1.5;">ô</span><span style="line-height:1.5;">te d’Ivoire in the management of sickle cell anemia. </span><span style="line-height:1.5;">This study was aimed at investigating the antisickling activity of the hydro-ethanolic extract </span><span "="" style="line-height:1.5;"><span>of a combination of the leaves of </span><i><span>J</span></i><span>. </span><i><span>secunda</span></i><span>, </span><i><span>J</span></i><span>. </span><i><span>gossypiifolia</span></i></span><span style="line-height:1.5;"> a</span><span "="" style="line-height:1.5;"><span>nd </span><i><span>P</span></i><span>. </span><i><span>nigrescens</span></i><span>.</span></span><span style="line-height:1.5;"> These three plants species were used in the Ivorian traditional herbal medicine. Preliminary phytochemistry was carried out using standard methods. As for the sickling reversal test, the Hb SS blood sickling was induced with 2% sodium metabisulfite. After 120 minutes of incubation, the plant extract was added. Every 30 minutes for a period of 120 minutes, a drop of the prepared solution was observed at (40</span><span style="line-height:1.5;">×</span><span "="" style="line-height:1.5;"><span>) magnification and the percentage of reversion calculated. The phytochemical analysis revealed the presence of Alkaloids, Flavonoids, Polyphenols, Catechic Tannins, Sterols and Polyterpenes. The results of the reversal test showed that the percentage of sickling reversal effect of the combination of the plants (75.00 ± 4.33</span><sup><span>b,c</span></sup><span>) was highly superior than the negative control (10.17 ± 0.55</span><sup><span>d</span></sup><span>) but was significantly (p < 0.05) the same as the percentage of the individual plant (</span><i><span>J</span></i><span>. </span><i><span>secunda</span></i><span>: 83.50 ± 2.33</span><sup><span>a</span></sup><span>;</span><i><span>J</span></i><span>. </span><i><span>gossypiifolia</span></i><span>: 78.00 ± 3.67</span><sup><span>b,c</span></sup><span> and </span><i><span>P</span></i><span>. </span><i><span>nigrescens</span></i><span>: 77.83 ± 2.89</span><sup><span>b,c</span></sup><span>) and the positive control (80.66 ± 2.22</span><sup><span>a,b</span></sup><span>). From the results, the extracts </span><i><span>J. secunda</span></i><span>, </span><i><span>J</span></i><span>. </span><i><span>gossypiifolia</span></i><span> and </span><i><span>P</span></i><span>. </span><i><span>nigrescens</span></i><span> have shown to be therapeutically beneficial to the population. Their use is also justified in the management of sickle cell disease in the south-eastern part of C</span></span><span lang="EN-US" style="line-height:1.5;">ô</span><span style="line-height:1.5;">te d’Ivoire.展开更多
The Gold District of Korhogo, in the northern region of C?te d’Ivoire, holds enormous potential for gold mineralizations, some of which are under exploration phase and others in exploitation phase (example of Tongon ...The Gold District of Korhogo, in the northern region of C?te d’Ivoire, holds enormous potential for gold mineralizations, some of which are under exploration phase and others in exploitation phase (example of Tongon Gold Mine). Dormant since 1998, Mapping Services of most of the West African countries hardly provide geological maps at the scales of: 1/200,000, 1/50,000 and 1/25,000. This situation of unavailability of detailed geological maps does not help mining operators in the selection of prolific areas and also in the interpretation of in soil geochem anomies or gold mineralizations. Consequently, during the years 2020 and 2021, we have undertaken a campaign of geological mapping and petro-structural study of the northern sector of Komborodougou, located in the southern extension of Banfora Birimian Belt. This work, which allowed the realization of a geological map at 1/20,000 scale, reveals that: the mapped area includes three (3) major lithological units: 1) a volcano-sedimentary unit made up of metasediments (metaarenites, metasiltites and metaflyschs) and metavolcanites (metabasalts), which are metamorphosed and outcrop in the form of schists;2) a metaplutonic and intrusive unit composed on the one hand of quartz-diorites and metagabbros, and on the other hand of granites and granodiorites;3) and finally, a unit of dikes formed by microgranites, microgabbros, aplites and quartzites. The volcano-sedimentary complex is affected by a regional fold with an axis subparallel to the regional tectonic grain and an S1 schistosity oriented NE-SW to NNE-SSW with steep dips (>60o), except for those of the metaflyschs which are weak (o);a regional NW-SE compression would be at the origin of the setting of this schistosity. The volcano-sediment and metaplutonite complex is crossed in a NNE-SSW direction by a senetral shear-zone or main shear-zone and secondary shear-zones oriented sometimes NE-SW or N-S. These shear-zones are intersected by more or less dextral or senestral strike-slip faults of NW-SE and E-W trends. N-S to NNE-SSW (N0o - N20o) and NW-SE (N130o - N160o) vein systems associated with the various shear-zones are the hosts of the gold mineralization in the region. These veins have been mined by orpaillors for more than two decades. The northern sector of Komborodougou is in the NNE continuity of the gold mineralization highlighted by the mining company Mako Gold Sarl on its Gogbala and Tchaga prospects, Napie project.展开更多
This paper studies the design and sizing of a filter (<em>L-C</em>) for an inverter with 180<span style="white-space:nowrap;"><span style="white-space:nowrap;">°<...This paper studies the design and sizing of a filter (<em>L-C</em>) for an inverter with 180<span style="white-space:nowrap;"><span style="white-space:nowrap;">°</span></span> control in Medium voltage (MV), based on formulas of the capacitance of the capacitor <em>C</em> and the inductance <em>L</em> of the filter (<em>L-C</em>) of an SPWM inverter. These formulas were obtained by minimizing two parameters: the reactive power of the capacitor (capped at 5% of the apparent power of the load) and the ripple of the current flowing through inductance <em>L</em> (capped at 10% of the current supplying the load). The application of these formulas for the calculation of the filter (<em>L-C</em>) of the 180<span style="white-space:nowrap;">°</span> control inverter in MV is not conclusive. Studies have been carried out to make them applicable. The results show that limiting the current ripple in the inductor to 10% of the load current is a valid assumption and that limiting the reactive power of the capacitor to 5% of the apparent power of the load presents shortcomings. The results also show that setting the inductance <em>L</em> of the filter to <em>L<sub>maxi </sub></em>and the capacitor <em>C </em>from 35 × <em>C<sub>maxi</sub></em> to 400 × <em>C</em><em><sub>maxi </sub></em>gives voltage and current THDs that meet the 519 IEEE-2014 standards.展开更多
The purpose of this work is to prepare better activated carbons from the shells of Ricinodendron Heudelotii by chemical activation with sulfuric acid (H<sub>2</sub>SO<sub>4</sub>) and sodium hy...The purpose of this work is to prepare better activated carbons from the shells of Ricinodendron Heudelotii by chemical activation with sulfuric acid (H<sub>2</sub>SO<sub>4</sub>) and sodium hydroxide (NaOH). The process was optimized by a full factorial design (2<sup>K</sup>) based on the analysis of the external specific surface area of sixteen (16) activated carbons prepared according to the parameters of the preparation. This active analysis reveals that under the preparation conditions, good carbons are obtained for a sodium hydroxide concentration equal to 1 M, an impregnation time of 24 h and carbonization at 500˚C for 1 h. The external specific surface of this carbon is 358 m<sup>2</sup><sup> </sup>•<sup></sup> g<sup>-1</sup>. The characteristics of this prepared carbon are as follows: a pH at zero point charge (pHpzc) of 8.2, a predominantly amorphous structure, a basic character and a low ash content (4.2%). It also has surface functions;the lactonic and carbonyl groups (C=O) at 1600 cm<sup>-1</sup> and the carboxylate groups (O-H or C-O) at 1340 cm<sup>-1</sup>.展开更多
文摘The granites and pegmatites located in the southern part of the Issia region, near the columbo-tantaliferous placers, are characterized by the presence of rare metals such as beryl, lithium and Nb-Ta oxides. They mainly consist of micas, quartz, plagioclase and potassium feldspar. The work carried out on the micas of these granites and pegmatites (EPMA analyses) has provided new geochemical data contributing to the understanding of the magmatic evolution of the Issia granite complex. Mineralogically, the most evolved G3 granites are characterized by their abundance of muscovite compared to biotite and the presence of pegmatite veins. Geochemically, the muscovites of the G1 and G2 granites are more ferriferous than those of the G3 granites, however, the latter display higher Na contents than the G2 and G3. The muscovites of the granites show an evolution from the pure muscovite series to the zinnwaldite series (micas of the pegmatites) which are lithium-bearing micas. The mineralogical and chemical data of the micas show that they are S-type peraluminous granites and demonstrate the formation of granites and pegmatites through fractional crystallization of the same parental magma.
文摘The aim of this study is to produce large quantities of yam tubers in the field from seed tubers derived from vitroplants regenerated from aerial stem cuttings and farmers’ tuber seeds. Seed tubers from ten yam cultivars, including five from Dioscorea alata (cDa083, cDa053, cDa115, cDa150 and cDa266) and five from Dioscorea cayenensis-rotundata (cDr015, cDr027, cDr150, cDr206 and cDr148) with distinct agro-morphological characteristics, were used as material. A completely randomized block design with 3 replications was used. In each block, all cultivars and seed types were represented. When put into cultivation, the tubers produced by the vitroplants all germinated and gave 100% healthy plants, compared with 86% to 100% healthy plants for the seed tubers produced by the farmers. Yields per hectare ranged from 10 to 25 tonnes for seed tubers produced by in vitro plants, and from 4 to 9 tons for seed tubers produced by farmers. Seed tubers from vitroplants can therefore be recommended to farmers as a solution to the problem of seed tuber unavailability.
文摘Drinking good quality water is essential for better health. It is therefore essential to assess the radiological quality of all water consumed in the District of Abidjan in order to prevent related hazards. Thus, the objective of this study was to assess the risk of cancer due to the ingestion of alpha and beta emitting radionuclides in the different types of water consumed in the region. A total of 63 water samples with 43 tap water samples, 5 bottled mineral water and 15 sachet water samples was collected and taken to GAEC laboratory for analysis. The low background Gas-less Automatic Alpha/Beta counting system (Canberra iMatic<sup>TM</sup>) was used to determine alpha and beta activity concentrations. Activity concentrations of both gross alpha and gross beta obtained in water sample were respectively lower than the WHO recommended limits of 0.1 Bq/l and 1 Bq/l. Also, the annual effective dose and total equivalent effective dose found in mineral bottled water samples were higher than in other types of water. The assessment of radiological lifetime risk has shown values of cancer risk due to ingestion alpha and beta emitters lower than recommended limit. These results indicate that there is no health hazard associated to consumption of water in the District of Abidjan.
文摘The present study was carried out on small-scale gold mining sites in the Yaouré region of Côte d’Ivoire. This region is geologically representative of the Birimian formations (2.1 Ga) of West Africa. The aim is to determine the potentially toxic trace metals (TMEs) generated by these sites, with a view to preventing possible contamination and/or metal pollution of the waters that provide fish products for local populations. To this end, a sampling campaign was carried out, resulting in the collection of 20 mining waste samples analyzed by X-ray fluorescence spectrometry (XRF) and 10 by X-ray diffractometer (XRD). The XRF analysis detected 06 predominant TMEs: arsenic, chromium, copper, nickel, zinc and vanadium. Statistical analysis was carried out to determine the distributions and correlations between these ETMs. To assess contamination and/or pollution levels, the following indices were calculated on the basis of reference concentrations of upper continental crust MTEs: Enrichment Factor, Geo-accumulation Index, Concentration Factor, Degree of contamination and those related to ecological risks. The results of statistical analyses and indices have shown that arsenic and chromium are the most predominant and can be, depending on the chemical form, potentially more toxic. The results of the DRX analysis show the occurrence of several minerals carrying these two MTEs, especially that of a rare mineral, Stenhuggarite, an arsenic oxide linked to hydrothermal veins. The majority of gold mining operations in West Africa are located in the birimian zone, hence the need for environmental monitoring by the relevant authorities, to prevent potential ecological risks to water and possibly health risks via the food chain.
文摘The availability of groundwater of acceptable quality has become a difficult challenge to meet in many countries, particularly Côte d’Ivoire. The State of Côte d’Ivoire and rural populations are building hydraulic infrastructure for this purpose. However, the quality of water coming from these infrastructures remains to be determined. This study therefore aims to analyze certain physicochemical parameters of the groundwater of Gloazra, Kouezra and Trahonfla. These are temperature, pH, electrical conductivity, TDS, salinity level, hardness, alkalinity, chloride content and bicarbonate. To determine the pH, electrical conductivity, temperature, TDS, and salinity rate, an electrochemical analysis was carried out. The titrimetric analysis made it possible to determine the chloride and bicarbonate content, alkalinity, and hardness. The results indicate that the studied groundwater is soft and acidic with good mineralization. This water does not present a health hazard to consumers but can affect hydraulic equipment and household containers.
文摘Data compression plays a key role in optimizing the use of memory storage space and also reducing latency in data transmission. In this paper, we are interested in lossless compression techniques because their performance is exploited with lossy compression techniques for images and videos generally using a mixed approach. To achieve our intended objective, which is to study the performance of lossless compression methods, we first carried out a literature review, a summary of which enabled us to select the most relevant, namely the following: arithmetic coding, LZW, Tunstall’s algorithm, RLE, BWT, Huffman coding and Shannon-Fano. Secondly, we designed a purposive text dataset with a repeating pattern in order to test the behavior and effectiveness of the selected compression techniques. Thirdly, we designed the compression algorithms and developed the programs (scripts) in Matlab in order to test their performance. Finally, following the tests conducted on relevant data that we constructed according to a deliberate model, the results show that these methods presented in order of performance are very satisfactory:- LZW- Arithmetic coding- Tunstall algorithm- BWT + RLELikewise, it appears that on the one hand, the performance of certain techniques relative to others is strongly linked to the sequencing and/or recurrence of symbols that make up the message, and on the other hand, to the cumulative time of encoding and decoding.
文摘This study assesses the projected changes in the climate zoning of Côte d’Ivoire using the hierarchical classification of principal components (HCPC) method applied to the daily precipitation data of an ensemble of 14 CORDEX-AFRICA simulations under RCP4.5 and RCP8.5 scenarios. The results indicate the existence of three climate zones in Côte d’Ivoire (the coastal, the centre and the north) over the historical period (1981-2005). Moreover, CORDEX simulations project an extension of the surface area of drier climatic zones while a reduction of wetter zones, associated with the appearance of an intermediate climate zone with surface area varying from 77,560 km<sup>2</sup> to 134,960 km<sup>2</sup> depending on the period and the scenario. These results highlight the potential impacts of climate change on the delimitation of the climate zones of Côte d’Ivoire under the greenhouse gas emission scenarios. Thus, there is a reduction in the surface areas suitable for the production of cash crops such as cocoa and coffee. This could hinder the country’s economy and development, mainly based on these cash crops.
文摘The West African Monsoon (WAM) is characterized by strong decadal and multi-decadal variability and the impacts can be catastrophic for the local populations. One of the factors put forward to explain this variability involves the role of atmospheric dynamics, linked in particular to the Saharan Heat Low (SHL). This article addresses this question by comparing the sets of preindustrial control and historical simulation data from climate models carried out in the framework of the CMIP5 project and observations data over the 20<sup>th</sup> century. Through multivariate statistical analyses, it was established that decadal modes of ocean variability and decadal variability of Saharan atmospheric dynamics significantly influence decadal variability of monsoon precipitation. These results also suggest the existence of external anthropogenic forcing, which is superimposed on the decadal natural variability inducing an intensification of the signal in the historical simulations compared to preindustrial control simulations. We have also shown that decadal rainfall variability in the Sahel, once the influence of oceanic modes has been eliminated, appears to be driven mainly by the activity of the Arabian Heat Low (AHL) in the central Sahel, and by the structure of the meridional temperature gradient over the inter-tropical Atlantic in the western Sahel.
文摘Chronic and potential non-healing wounds are a great challenge for patients, physicians, and wound care professionals and the health system. A balanced nutrition intake is essential for health as well as a speedy recovery of such wounds. The study objective was to compare chronic wound inpatients supplemented with food nutrient content with outpatients with their usual intake in a cross-sectional study. Patients’ food samples were taken for chemical analyses. The protein, beta-carotene, sodium, magnesium, manganese, and potassium content prove statistically significant differences. Outpatients’ diets are more diversified than inpatients’ diets, and supplementation diet richest in beta-carotene and in protein. Outpatients have better dietary diversity than those who were hospitalized. The result provides insights of supplementary food as critical issues pertaining to chronic wounds management. However, analyzing bioavailability of nutrient on patients’ blood may provide more knowledge in the appropriate integrated wound management.
文摘Background: Acute intoxications result from intentionally or accidentally taking a relatively significant amount of a chemical substance which triggers disturbances in the level of psychophysiological functions, the complications of which may lead to mental disorders, physical causalities, and death. Any acute intoxication mostly requires emergency care. Objective: To highlight the prevalence, history, clinical features, emergency treatment, and prediction of acute intoxication cases referred to the emergency services at the Provincial General Reference Hospital in Bukavu, DR-Congo. Methods: A retrospective cross-sectional study was conducted from January 2021 to October 2022 based on an analysis of patients’ medical files. Triage was performed among all-type of patient files recorded in the computerized hospital database Ebale-Sante to sort cases of intoxication. Results: During the observational period, 3966 emergency admissions were counted, of which 321 (8.09%) patients were identified as having acute intoxication. Among these, 100 files that containing sufficient information fit the quality criteria for this study’s analysis. The victims were infants, adolescents and adults aged 1 - 45 years, and 52% were female and 48% were male. Most cases were accidental and, occurred at home, and the victims were driven to the hospital within 2 - 24 hours. The substances consumed included household products, drugs, and herbs. Resuscitation care, antidotes and supportive symptomatic medications ensured that 85% were healed and 10% experienced sequelae;however, 5% died. Conclusion: Acute intoxication occurs in infants mostly accidentally though the ingestion of household products and medicines. Furthermore, suicide cases may occur in traumatized adolescents and discordant couples. People should be informed about how to store hazardous products (e.g.: drugs, household products and pesticides), which should not be available to children, to avoid unintentional poisoning. Special training in clinical toxicology is required to reduce treatment failure.
文摘Background: Type II diabetes mellitus is associated with multiple metabolic derangements which can cause secondary pathophysiological changes in multiple organ systems. This in turn can impose a heavy burden of morbidity and mortality from micro‑ and macro‑vascular complications. This study aimed to describe the metabolic and therapeutic profile of a subgroup of type 2 diabetic patients who have treatment failure with oral anti-hyperglycemic agents with persistent hyperglycemia despite insulin treatment. Methods: 60 type 2 diabetic patients in treatment failure with oral antidiabetics and under insulin treatment, aged 35 to 70 years, were recruited at the Diabetes Clinic of the University Teaching Hospital of Treichville in Abidjan, Côte d’Ivoire. Blood samples were collected in tubes containing Ethylenediaminetetraacetic Acid (EDTA) to determine glycated hemoglobin (HbA1c). Results: The average age of the population was 54 ± 9.38 years with a sex ratio (M/F) of 0.3, an average BMI of 30.25 ± 5 kg/m<sup>2</sup>, and an average HbA1c of 10.1% ± 1.6% for an average diabetes duration of 11.8 ± 5.8 years. The average insulin dose was 74.556 ± 16.21 UI/day, and the average duration of insulin treatment was 5.4 ± 3.1 years. The average HbA1c value was 10.1% ± 1.87% in men against 10.03% ± 1.53% in women with no significant difference (p = 0.1). The mean HbA1c values according to patient weight were 10.08% ± 2.05% for normal weight, 9.55% ± 2.26% for overweight, and 10.57% for obese, with no significant difference between the three groups of patients (p = 0.1). Conclusion: This study showed a persistence increase in glycated hemoglobin regardless of the treatment regimen, duration, and dose of insulin treatment in the subpopulation of type 2 diabetic patients.
文摘Sickle cell disease (SCD) is a genetic blood disorder that affects the shape and transportation of red blood cells (RBCs) in blood vessels, leading to various clinical complications. Sickle cell disease is a widespread genetic disease in Black Africa. The objective of this study was to evaluate the sickling inhibition activity of Griffonia simplicifolia. Quantitative and qualitative tests were used to determine the major groups of secondary metabolites present in the Griffonia simplicifolia leaves extracts and the modified Emmel test was used to perform the study of sickling inhibition activity. The OECD 423 toxicity study showed that at a single dose of 2000 mg/kg bw, Griffonia simplicifolia leaves extracts are not toxic. All tested substances inhibit erythrocyte falciformation in a dose-dependent manner. The percentages of inhibition were 50.35%, 73% and 94.23% for aqueous extract, hydromethanolic extract and phenylalanine respectively at the concentration of 15 mg/mL. The methanolic extract (70%) had higher activity compared to the aqueous extract. These results suggest that the Griffonia simplicifolia extracts have some potential to be used as alternative antisickling therapy in SCD management.
文摘This paper deals with the security of stock market transactions within financial markets, particularly that of the West African Economic and Monetary Union (UEMOA). The confidentiality and integrity of sensitive data in the stock market being crucial, the implementation of robust systems which guarantee trust between the different actors is essential. We therefore proposed, after analyzing the limits of several security approaches in the literature, an architecture based on blockchain technology making it possible to both identify and reduce the vulnerabilities linked to the design, implementation work or the use of web applications used for transactions. Our proposal makes it possible, thanks to two-factor authentication via the Blockchain, to strengthen the security of investors’ accounts and the automated recording of transactions in the Blockchain while guaranteeing the integrity of stock market operations. It also provides an application vulnerability report. To validate our approach, we compared our results to those of three other security tools, at the level of different metrics. Our approach achieved the best performance in each case.
文摘Since 2015, Côte d’Ivoire has been the world’s largest cashew producer. However, cashew orchards in Côte d’Ivoire are infected by fungal diseases that weaken production. And the contribution of weeds to the spread of these diseases is not yet understood. This study was initiated with the aim of establishing the role of weeds in the proliferation of pathogenic fungi in orchards. It consisted of a survey of weeds showing disease symptoms in cashew orchards in Côte d’Ivoire from February 2021 to July 2022. The itinerant method was used for the weed inventory. Symptomatic leaves were collected and sent to the laboratory for diagnosis on PDA (Potatoes Dextrose Agar) medium. In total, 50 species in 46 genera and 23 families were recorded. Laboratory diagnosis of the samples showed that 80% of the weeds identified harboured pathogenic fungi. The highest infection rates were obtained on Danielia oliveri R. (99.33% to 100%), Vitellaria paradoxa G. (100%), Pterocarpus erinaceus P. (83.91% to 99.33%), Micuna pruriens L. (98.33% to 100%) and Isoberlinia doka C. et S. (56.33% to 100%). The diagnosis revealed the presence of Lasiodiplodia sp, Colletotrichum sp, Pestalotia sp, Alternaria sp and Curvularia sp on weeds in the cashew orchard in Côte d’Ivoire.
文摘Introduction: Abnormalities in mineral and bone metabolism, particularly phosphocalcic metabolism, are common in renal failure and are associated with a significant morbidity and mortality. The regulation of phosphocalcic metabolism is subject to a particularly precise and complex control of parathormone (PTH) and vitamin D. Assessment of vitamin D and parathyroid hormone concentrations would help to improve the medical management of patients with chronic kidney disease and ensure a better quality of life. Methods: The study population consisted of 138 individuals including 46 non- dialysis renal failure patients, 46 chronic hemodialysis patients and 46 non- renal failure volunteers to serve as controls. Serum Parathyroid hormone and Vitamin D concentrations were measured using the Vidas automated system. Results: 25-hydroxyvitamin D concentrations in controls (65 ± 2.41 nmol/L) and dialysis patients (70 ± 3.03 nmol/L) were significantly higher than those in CKD patients (48 ± 3.34 nmol/L). On the other hand, the mean values of Parathyroid hormone in dialysis patients (312 ± 36.22 pg/mL) and CKD patients (117 ± 10.68 pg/mL) were very high compared to that in controls (25 ± 2.34 pg/mL). Conclusion: Secondary hyperparathyroidism is common in renal failure. Parathyroid hormone and 25-hydroxyvitamin D assays would be adequate for better management of chronic renal failure.
文摘Introduction: The study of mortality is an indicator that allows a control and a review of the therapeutic measures in the hospital environment. The purpose of this work was to determine the epidemiological profile of the patients who died and analyse the circumstances of the death in a hospital service. Material and Methods: It is a retrospective descriptive study conducted in the service of Stomatology, maxillofacial and plastic surgery of the face over a period of 10 years (from January 1999 to December 2008). Seventy-two cases have been taken into account. Results: The crude death rate was 4.29%. Higher level of male has been noted with a sex ratio of 1.77. The most affected age groups were the 3rd and 2nd decades, respectively with 20.8% and 19.4% with an average age of 39 years. Cellulitis of the face and their complications were responsible for deaths in 58.33% of cases. The majority of deaths occurred between 6 p.m. and 6 a.m. (65.28%). These deaths were preventable in 5.6% of cases. Conclusion: Facing the lack of description of the ultimate circumstances of death in the medical records, the conclusion of this study has been the establishment of a regular medical audit in the service, which would track mortality in order to reduce its rate.
文摘<span style="line-height:1.5;">Natural plant products have been used by the population of the south-eastern part of C</span><span lang="EN-US" style="line-height:1.5;">ô</span><span style="line-height:1.5;">te d’Ivoire in the management of sickle cell anemia. </span><span style="line-height:1.5;">This study was aimed at investigating the antisickling activity of the hydro-ethanolic extract </span><span "="" style="line-height:1.5;"><span>of a combination of the leaves of </span><i><span>J</span></i><span>. </span><i><span>secunda</span></i><span>, </span><i><span>J</span></i><span>. </span><i><span>gossypiifolia</span></i></span><span style="line-height:1.5;"> a</span><span "="" style="line-height:1.5;"><span>nd </span><i><span>P</span></i><span>. </span><i><span>nigrescens</span></i><span>.</span></span><span style="line-height:1.5;"> These three plants species were used in the Ivorian traditional herbal medicine. Preliminary phytochemistry was carried out using standard methods. As for the sickling reversal test, the Hb SS blood sickling was induced with 2% sodium metabisulfite. After 120 minutes of incubation, the plant extract was added. Every 30 minutes for a period of 120 minutes, a drop of the prepared solution was observed at (40</span><span style="line-height:1.5;">×</span><span "="" style="line-height:1.5;"><span>) magnification and the percentage of reversion calculated. The phytochemical analysis revealed the presence of Alkaloids, Flavonoids, Polyphenols, Catechic Tannins, Sterols and Polyterpenes. The results of the reversal test showed that the percentage of sickling reversal effect of the combination of the plants (75.00 ± 4.33</span><sup><span>b,c</span></sup><span>) was highly superior than the negative control (10.17 ± 0.55</span><sup><span>d</span></sup><span>) but was significantly (p < 0.05) the same as the percentage of the individual plant (</span><i><span>J</span></i><span>. </span><i><span>secunda</span></i><span>: 83.50 ± 2.33</span><sup><span>a</span></sup><span>;</span><i><span>J</span></i><span>. </span><i><span>gossypiifolia</span></i><span>: 78.00 ± 3.67</span><sup><span>b,c</span></sup><span> and </span><i><span>P</span></i><span>. </span><i><span>nigrescens</span></i><span>: 77.83 ± 2.89</span><sup><span>b,c</span></sup><span>) and the positive control (80.66 ± 2.22</span><sup><span>a,b</span></sup><span>). From the results, the extracts </span><i><span>J. secunda</span></i><span>, </span><i><span>J</span></i><span>. </span><i><span>gossypiifolia</span></i><span> and </span><i><span>P</span></i><span>. </span><i><span>nigrescens</span></i><span> have shown to be therapeutically beneficial to the population. Their use is also justified in the management of sickle cell disease in the south-eastern part of C</span></span><span lang="EN-US" style="line-height:1.5;">ô</span><span style="line-height:1.5;">te d’Ivoire.
文摘The Gold District of Korhogo, in the northern region of C?te d’Ivoire, holds enormous potential for gold mineralizations, some of which are under exploration phase and others in exploitation phase (example of Tongon Gold Mine). Dormant since 1998, Mapping Services of most of the West African countries hardly provide geological maps at the scales of: 1/200,000, 1/50,000 and 1/25,000. This situation of unavailability of detailed geological maps does not help mining operators in the selection of prolific areas and also in the interpretation of in soil geochem anomies or gold mineralizations. Consequently, during the years 2020 and 2021, we have undertaken a campaign of geological mapping and petro-structural study of the northern sector of Komborodougou, located in the southern extension of Banfora Birimian Belt. This work, which allowed the realization of a geological map at 1/20,000 scale, reveals that: the mapped area includes three (3) major lithological units: 1) a volcano-sedimentary unit made up of metasediments (metaarenites, metasiltites and metaflyschs) and metavolcanites (metabasalts), which are metamorphosed and outcrop in the form of schists;2) a metaplutonic and intrusive unit composed on the one hand of quartz-diorites and metagabbros, and on the other hand of granites and granodiorites;3) and finally, a unit of dikes formed by microgranites, microgabbros, aplites and quartzites. The volcano-sedimentary complex is affected by a regional fold with an axis subparallel to the regional tectonic grain and an S1 schistosity oriented NE-SW to NNE-SSW with steep dips (>60o), except for those of the metaflyschs which are weak (o);a regional NW-SE compression would be at the origin of the setting of this schistosity. The volcano-sediment and metaplutonite complex is crossed in a NNE-SSW direction by a senetral shear-zone or main shear-zone and secondary shear-zones oriented sometimes NE-SW or N-S. These shear-zones are intersected by more or less dextral or senestral strike-slip faults of NW-SE and E-W trends. N-S to NNE-SSW (N0o - N20o) and NW-SE (N130o - N160o) vein systems associated with the various shear-zones are the hosts of the gold mineralization in the region. These veins have been mined by orpaillors for more than two decades. The northern sector of Komborodougou is in the NNE continuity of the gold mineralization highlighted by the mining company Mako Gold Sarl on its Gogbala and Tchaga prospects, Napie project.
文摘This paper studies the design and sizing of a filter (<em>L-C</em>) for an inverter with 180<span style="white-space:nowrap;"><span style="white-space:nowrap;">°</span></span> control in Medium voltage (MV), based on formulas of the capacitance of the capacitor <em>C</em> and the inductance <em>L</em> of the filter (<em>L-C</em>) of an SPWM inverter. These formulas were obtained by minimizing two parameters: the reactive power of the capacitor (capped at 5% of the apparent power of the load) and the ripple of the current flowing through inductance <em>L</em> (capped at 10% of the current supplying the load). The application of these formulas for the calculation of the filter (<em>L-C</em>) of the 180<span style="white-space:nowrap;">°</span> control inverter in MV is not conclusive. Studies have been carried out to make them applicable. The results show that limiting the current ripple in the inductor to 10% of the load current is a valid assumption and that limiting the reactive power of the capacitor to 5% of the apparent power of the load presents shortcomings. The results also show that setting the inductance <em>L</em> of the filter to <em>L<sub>maxi </sub></em>and the capacitor <em>C </em>from 35 × <em>C<sub>maxi</sub></em> to 400 × <em>C</em><em><sub>maxi </sub></em>gives voltage and current THDs that meet the 519 IEEE-2014 standards.
文摘The purpose of this work is to prepare better activated carbons from the shells of Ricinodendron Heudelotii by chemical activation with sulfuric acid (H<sub>2</sub>SO<sub>4</sub>) and sodium hydroxide (NaOH). The process was optimized by a full factorial design (2<sup>K</sup>) based on the analysis of the external specific surface area of sixteen (16) activated carbons prepared according to the parameters of the preparation. This active analysis reveals that under the preparation conditions, good carbons are obtained for a sodium hydroxide concentration equal to 1 M, an impregnation time of 24 h and carbonization at 500˚C for 1 h. The external specific surface of this carbon is 358 m<sup>2</sup><sup> </sup>•<sup></sup> g<sup>-1</sup>. The characteristics of this prepared carbon are as follows: a pH at zero point charge (pHpzc) of 8.2, a predominantly amorphous structure, a basic character and a low ash content (4.2%). It also has surface functions;the lactonic and carbonyl groups (C=O) at 1600 cm<sup>-1</sup> and the carboxylate groups (O-H or C-O) at 1340 cm<sup>-1</sup>.
