Electrochemical Analysis of Zirconiumin Aqueous and Organic Media

For the challenging nature of the zirconium environment analysis, this study consists to analyze the electrochemical behavior of Zirconium in both aqueous and organic media. To that end first the electrolytic media was selected on the basis of the Pourbaix potential-pH diagram, which provides informations on the predominance of Zr(IV) ion and Zr in aqueous media. In aqueous media, analyzes were first carried out in acidic media then in basic media. Studies have thus revealed that the acidic environment is not favourable for the electrochemical analysis of zirconium. Voltammograms obtained in an acidic environment show no zirconium detection signal;this is due to the strong presence of H+ ions in the solution. We have also observed in acidic media the phenomenon of passivation of the electrode surface. In aqueous alkaline media (pH = 13), we have drawn in reduction several Intensity-Potential curves by fixingsome technical parameterslike scanning speed, rotation speed of the electrode. The obtained voltammograms show cathodic waves, starting from -1.5 V/DHW and attributed to the reduction of Zr (IV) to Zr (0). The last phase of this study focused on the electrochemical analysis of zirconium in an organic media. In this media, several intensity-potential curves were plotted in reduction and in cyclic voltammetry with various parameters. Through several reduction analysis, the Zr (IV) was reduced to Zr (0) to the potential of -1.5 V/DHW. The electrochemical analysis of zirconium in organic media seems globally easier to achieve thanks to its large solvent window (i.e. dimethylformamide (DMF) solvent window > 6 V).

Coordination of Regulation Devices for Damping Power Oscillations in a Dynamic Disturbance Context: A Fuzzy Logic-Based Approach Applied to the Electrical Grid of the Republic of Congo

This article presents a fuzzy logic-based approach to coordinate the control devices of the power system, such as Power System Stabilizers (PSS) and Static Synchronous Compensators (STATCOM), to damp power oscillations caused by dynamic disturbances. At first, we used the Lyapunov method to study the dynamic stability of the power grid in the Republic of Congo. This method allowed us to analyze the eigenvalues of the state variable matrix and highlight the eigenvalues in the complex plane. Secondly, we proposed a fuzzy logic-based controller to account for uncertainties existing near the thresholds. The inputs to this controller are the generator speed and generator rotor angle. We demonstrated the effectiveness and feasibility of this fuzzy control by applying it to the power grid of the Republic of Congo, with three power stabilizers and two STATCOMs. .

Sweetener and Flavor Enhancer Food Additives in Industrial Food Products Marketed in Dakar: Frequency and Diversity

Sweeteners and flavor enhancers are food additives widely used in industry, respectively, to add sweetness and flavor to foods. However, the presence of these substances is often criticized by consumers for their effects on health. What’s more, some scientific studies link these substances to certain pathologies. To guarantee food safety, competent authorities should have food standards based on risk analysis using consistent, reliable data. However, in developing countries, such data is often weak or non-existent. The aim of this study is therefore to carry out a pilot survey to establish the profile of sweeteners and flavour enhancers present in industrial food products marketed in Senegal. The methodology consisted of sampling various food products sold on the Senegalese market, based on analysis of labels containing information on ingredients, including additives. The investigation involved nine stores, one supermarket and 5 mini-markets in Dakar. The results showed the presence of 6 taste enhancers in food products, the most frequent being sodium L-monoglutamate (E621), inosinate (E631) and disodium guanylate (E627). Solid broths are the foodstuffs with the highest number of taste exhalters. As for sweeteners, 12 substances were identified, the most frequent being acesulfame potassium (E950), aspartame (E951), sucralose (E955) and saccharin (E954). Given the potential health risks associated with the consumption of these food additives, their control and monitoring on the market should be a priority for the competent authorities.

Evaluation of the Inhibitory Gel Aloe vera against Corrosion of Reinforcement Concrete in NaCl Medium

Most reinforced concrete structures in seaside locations suffer from corrosion damage to the reinforcement, limiting their durability and necessitating costly repairs. To improve their performance and durability, we have investigated in this paper Aloe vera extracts as a green corrosion inhibitor for reinforcing steel in NaCl environments. Using electrochemical methods (zero-intensity chronopotentiometry, Tafel lines and electrochemical impedance spectroscopy), this experimental work investigated the effect of these Aloe vera (AV) extracts on corrosion inhibition of concrete reinforcing bar (HA, diameter 12mm) immersed in a 0.5M NaCl solution. The results show that Aloe vera extracts have an average corrosion-inhibiting efficacy of around 86% at an optimum concentration of 20%.

Assessment of Groundwater Quality for Drinking and Irrigation Uses in the Samba Dia Area, Central West Senegal

In the Sahelian zone in Africa, groundwater is the main source of drinking water for domestic, industrial, and agricultural uses. The groundwater of the Samba Dia sandy aquifer was assessed for understanding processes controlling the hydrogeochemistry and its drinking and irrigation suitability, on the basis of various water quality parameters. For the present study, thirty-three groundwater samples were collected in wells of the study area during the dry season in March 2021 and subjected to analysis for chemical characteristics (major ions), pH, electrical conductivity (EC), and total dissolved solids (TDS). Gibbs plot depicts that the process of ionic exchange is mainly due to the dissolution of water-rock interaction. The Piper diagram indicates a largely dominant sodium chloride facies with 70% of the groundwater samples followed by calcium chloride facies (18%) than calcium bicarbonate facies (12%). Analytical results of hydrogeochemical parameters of groundwater samples reveal that the majority of samples are within the World Health Organization safety range for drinking water. TDS and electrical conductivity (EC) values of groundwater indicate that 70% and 61% are safe for drinking water, respectively. Sodium percentage (% Na), Sodium Adsorption Ratio (SAR) values, and Ca/Mg ratio were calculated and compared with the standard guideline values recommended by the World Health Organization and agricultural water standards. This study shows that the groundwater in the area is mostly chemically suitable for drinking and irrigation, although some wells at the edge of the area exhibit signs of progressive salinization and traces of pollution.

Response Surface Methodology as an Approach for Optimization of Vinegar Fermentation Conditions Using Three Different Thermotolerant Acetic Acid Bacteria

This study aimed to investigate optimal fermentation conditions of biological acetic acid fermentation for vinegar production. Optimization was performed on 3 acetic acid bacteria strains namely VMA1, VMA7 and VMAO using Response Surface Methodology (RSM). A Box-Behnken-Design (BBD) was achieved with three different independent process parameters involving: fermentation temperature, original alcohol concentration and original acetic acid concentration and one dependent variable (acetic acid yield). The results showed that the mathematical models describe correctly the relationship between responses and factors (F values of the models (p R2 (coefficient of correlation) respectively 0.96, 0.94, 0.98, and adjusted R2 0.95, 0.92, 0.98). The maximum acidity was obtained respectively at fermentation temperatures, original alcohol concentrations and original acetic acid concentrations ranging from [37.5°C - 45°C], [16% - 20% (v/v)], [1.5% - 2% (w/v)] for VMA1, [40°C - 45°C], [14.5% - 20% (v/v)], [1.7% - 2% (w/v)] for VMA7 and [42°C - 45°C], [17% - 20% (v/v)], [1.5% - 2% (w/v)] for VMAO. The use of these acetic strains in the production of vinegar may seriously lead to a decrease or even an ablation of the costs related to the cooling of bioreactors especially in warm and hot countries, in the context of global warming.

Identification of Natural and Artificial Colorants in Industrial Products Marketed in Senegal

Food colorants are widely used in the food industry to maintain or enhance product color. However, as the use of these colorants can have negative impacts on health, it is essential to analyze the risks associated with their consumption. This analysis requires, among other things, obtaining sufficient data on the presence of these colorants in foods, as well as their level of consumption. However, data on these colorants is often virtually non-existent in developing countries. The aim of this study was to determine the colorant profile of industrial products marketed in Senegal. Information on food additives was collected on 399 labels of different food product categories in shops located in Dakar. Data is recorded and processed using Excel software. Based on the Codex classification, analysis of the profile of additives identified on the labels of food samples revealed the presence of 31 colorants. The natural colorants identified are dominated by beta-carotene, widely present in beverages and dairy products, and paprika extract identified on cookies and industrial sauces. Artificial colors are dominated caramels present in several foods including bouillons, vinegars, sauces and hard candies. Secondly, there was a strong presence of the azo dye Sunset yellow FCF, widely found in samples of beverages, confectionery and cookies. The results of this case study enable us to appreciate the wide presence and diversity of colorants on the Senegalese market, and the importance of controlling them to guarantee consumer safety.

Profile of the Functional Categories of Food Additives in Industrial Foods Marketed in Senegal

Food additives, whether natural or artificial substances, are widely used around the world to improve the sensory quality of products, extend their shelf life and make them more competitive. However, the abusive and uncontrolled consumption of food additives is the cause of numerous illnesses and diseases such as poisoning, allergies, diabetes and numerous cancers. So, in addition to setting up control and regulatory bodies, it is becoming essential to keep a constant watch on the presence of food additives on the market. The aim of this study is to highlight the main categories of food additives in food products frequently sold on the Senegalese market. The methodology of the study is based on the identification of food additives from the information given on the labels of food packaging. Information was collected in markets in two (2) major regions of Senegal: Dakar and Saint-Louis. The results of our study show the presence of 153 food additives on the labels of 514 samples collected. Moreover, the frequency and diversity of additives depended on the food category. On the other hand, beyond their important technological and functional roles, some additives such as aspartame and monosodium glutamate have been implicated in pathologies, and others, such as titanium dioxide, are the subject of much controversy and even withdrawal in certain legislations for their impacts deemed potentially negative on consumer health.

Process Optimization and Modeling by Response Surface Methodology of Nitrite Electro-Reduction by Ti/RuO2 + IrO2 Electrode

Electrochemical reduction is one of the most suitable methods for the treatment of highly nitrate-contaminated solutions. This work focuses on the optimization of parameters influencing the electrochemical denitrification of water by the Ti/RuO2 + IrO2 electrode. The methodological approach used consists in carrying out a series of electrolysis by scrutinizing the reaction selectivity according to the experimental conditions. For this study, the ions concentrations before and after electrolysis were determined by UV-vis absorption spectroscopy. The results of the process optimization showed that the electrochemical reduction ofis efficient at neutral pH after 120 mn of electrolysis at -100 mA. In contrast to works found in the literature, this study highlighted the process modeling that could open interesting perspectives to develop new treatment methods of polluted waters.

Study of the Impact of Grid Disconnections on the Production of a Photovoltaic Solar Power Plant: Case of Diamniadio Power Plant

Today, renewable energy projects connected to the interconnected network, with powers of the order of tens of megawatts, are more and more numerous in sub-Saharan Africa. And financing these investments requires a reliable amortization schedule. In the context of photovoltaic systems connected to the interconnected electricity grid, the quintessence of damping is the amount of energy injected into the grid. Thus it is fundamental to know the parameters of this network and their variation. This paper presents an evaluation of the impact of power grid disturbances on the performance of a solar PV plant under real conditions. The CICAD photovoltaic solar plant, connected to the Senelec distribution network, with an installed capacity of 2 MWp is the study setting. An energy audit of the plant is carried out. Then the percentage of each loss is determined: voltage drops, module degradation, inverter efficiency. The duration of each disconnection is measured and recorded daily. The corresponding quantity of lost energy is thus calculated from meteorological data (irradiation, temperature, wind speed, illumination) recorded by the measurement unit in one-minute steps. The observation period is three months. The total duration of disconnections related to the instability of the electrical network during the study period is 46.7 hours. The amount of energy lost is estimated at 22.6 MWh. This represents 2.4% of the actual calculated production.

Broiler Feet Gelatine

The two waves period of the COVID-19 pandemic saw the use of hydro- alcoholic gel and the consumption of capsules containing improved traditional remedies. At one point, there was a stock-out and a price increase forthese products. Furthermore, in the food industry, the catering industry adopts gelatin in its current practice. Pig gelatin dominates the international market. And for some religious practices, pork is forbidden and yet these people consume them without taking notice. The production of gelatin from broiler feet seems economically viable because broiler feet are considered slaughterhouse waste that is sold at very low prices. The poultry industry has seen an increase in broiler farming over the last twenty years. However, the latter has all the characteristics required for the production of gelatin. It will therefore comply with the standards of use described in the international codex oenological for gelatins. Physical and chemical analyses such as, ash content, moisture content, and pH measurements were done for the extracted gelatins. Sensible elements are checked with ED XRF spectroscopy. All the results were good and showed without any doubt that broiler gelatin is edible.

Assessment of Trends in the Development of the It Market

The demand for information technology in a new way forced us to reconsider our views on the state of the information and communication technology market. The analysis of the trend in the development of the information space is necessary for the formation of a scenario for the formation of a stable information and communication industry in the hotel state. The article proposes the structure of the IT market, defines the role of its main parts and concludes about their impact on the further development of the IT industry. A brief overview of the components of the modern IT market is presented. The greatest influence is provided by cloud solutions, the Internet of Things market and digital products in the field of artificial intelligence. Observation of changes in the IT market allows us to predict further events related to digitalization. In conclusion, possible ways of developing the IT market are given.

Prospects of Using Low-Code in the Creation of Automated Systems

Ever-changing market conditions and a rapidly changing IT landscape call for fast and cheap ways to meet software demands. In order to tackle these problems, low-code development platforms (LCDPs) have emerged. These platforms are designed with the idea to limit recurring traditional hand-coding and programming. This article provides a theoretical overview of low-code solutions. The advantages and disadvantages of using LCDP in the creation of automated systems are considered. In conclusion, a conclusion is formulated about the prospects of using low-code technology.

Northeastern Tropical Atlantic SST and Sahel Rainfall Variability

The SST variability during the summer period in the northeastern tropical Atlantic region (NTA) is characterized by an alternation of warming/cooling which represents 87% of the total variability. The aim of this paper is to study the atmospheric responses as well as the precipitation associated with these oceanic conditions. Based on Reynolds’s SST from 1982 to 2019, a normalized Northern Tropical Atlantic index (NTAI) is computed into the region between 15° - 25°W;12° - 16°N and a composite analysis is then performed. It is shown that the NTAI is significantly correlated with the SST’s first principal component mode (PC1) in this region. Moreover, the composite of SST anomalies and atmospheric parameters exhibits a strong local ocean-atmosphere interaction which highly impacts the large-scale atmospheric circulation in West Africa, particularly in the western Sahel. An in-depth analysis shows that the atmospheric response to the warm (cold) SST is a cyclonic (anticyclonic) circulation in the lower layers near the West Africa Coast. This cyclonic (anticyclonic) circulation strengthens/reduces the moisture transport towards the continent in the low levels. In the middle layers of the atmosphere (500 hPa), the warm (cold) composite is associated with a decrease (increase) in the intensity of the African Easterly Jet (AEJ) whereas, in the upper atmosphere (200 hPa), the strengthening (weakening) of the Tropical Easterly Jet (TEJ) is observed. With regard to the composite precipitation field, a positive/negative SST anomaly is associated with significantly enhanced/reduced rainfall in the western Sahelian region. It is found that this relationship (correlation) increases as we are closer to the coasts.

Evaluation of the Influence of Plastic Waste in Improving the Mechanical Characteristics of Asphalt Mixes (Senegal, West Africa)

The recovery of plastic waste has a positive impact on two fronts: The environment, through waste reduction, and the economy, through its use in road construction. This work involves recycling plastic variants such as Polypropylene (PP) 50% and LDPE (Low Density Polyethylene) 50% in proportions of 2% to 8%, incorporated into a 0/14 BBSG. The results of the Marshall test gave stability values ranging from 826 to 1523 kg and creep values from 5.5 to 2.45 mm. The Duriez test gave r/R values ranging from 0.769 to 0.786, with water absorption percentages from 2.24% to 0.69%. The PCG test at 80 gyrations gave void percentages ranging from 11.9% to 5.23%. The rutting test gives a rutting depth percentage that drops at 30,000 cycles from 11.5% to 1.3%. This study shows a considerable increase in the mechanical characteristics of asphalt mixes by adding plastic waste.

Crustal structure beneath Cameroon from EGM2008

We used the Earth Gravitational Model （EGM2008） data sets to analyze the regional gravity anoma- lies and to study the underground structures in Cameroon. We first created a high-resolution Free-Air anomaly database, then corrected the gravity field of the topographic effect by using ETOPO1 DEM with a resolution of 0.01~ to obtain the Bouguer anomaly, then applied a multi-scale wavelet-analysis technique to separate the gravity-field components into different parts of shallow-to-deep origins, and finally used the logarithmic power spectrum technique to obtain detailed images and corresponding source depths as well as certain lateral inho- mogeneity of structure density. The anomalies of shallow origin show successive elongated gravity ＂highs＂ and ＂lows＂ attributable to subsurface Tertiary and lower Cretaceous undulations. Our results are in good agreement with previous investigations.

Illumination Level Effects on Macroscopic Parameters of a Bifacial Solar Cell

This study presents a method based on the experimental measurement of the short-circuit current (Icc) and the open circuit voltage (Vco) of the solar cell. It permits the determination of recombination parameters such as: diffusion length (L), back surface recombination velocity (Sb), intrinsic junction recombination velocity (Sjo), and macroscopic parameters in particular, the shunt and series resistances of a bifacial solar cell for various illumination levels (n). Illumination level effects on macroscopic parameters are highlighted.

Nutritional Contribution of Some Senegalese Forest Fruits Running across Soudano-Sahelian Zone

As a good food supply for the local people in various Senegalese regions, the forest fruits are becoming very important. They are using between foods or main condiment for dishes in many part of Africa. These fruits represent non negligible sources of vitamins, carbohydrates and minerals. Instead of more commercialized species such as Adansonia digitata L., Detarium senegalensis J.F.Gmel., Saba senegalensis (A.DC.) Pichon, Tamarindus indica L., this article focused on nutritional values of other fruits with little interest or neglected. These species were Ficus gnaphalocarpa, L., Cordyla pinnata (Lepr. ex A.Rich.) Milne-Redh. and Icacina senegalensis, harvested in soudano-sahelian zone;while Sarcocephalus latifolius (Sm.) E.A. Bruce belongs to Sudanese zone. The fruit pulps were isolated and freeze dried before analysis. The results showed that acidity, vitamin C and total minerals were significantly different from one fruit to another. S. latifolius with the highest acidity content (402.43 mg/100 g) and best vitamin C content if 1488 mg/100 g were found. Also as results, S. latifolius provided high protein content nearby the 20%. The caloric contributing (kcal/100 g) were 102.5, 177 and 132 respectively for F. gnaphalocarpa, C. pinnata, and S. latifolius. The ash contents were the same for all species (4.5%), indicating the richness in mineral elements. Furthermore, all species in this study were good sources of iron, copper and zinc. However, small amounts of sodium were noticed in all samples. Analysis of total sugars and their profile showed that I. senegalensis and C. pinnata were more appreciated. These results predicted the useful incomes for forest fruits in human being. Lot of medicinal virtues has been recognized from these fruits. The increase in value and the preservation of the biodiversity are necessary particularly for C. pinnata which presents a serious threat because of the strong income for wood production.

Comparative Study between the PID Regulator and the Fuzzy Regulator Applied to the Operation of a Brushless DC Motor

This paper presents the results of research on speed regulation of a brushless DC motor. This is mainly a comparative study between a PID regulator and a fuzzy regulator applied to the operation of this type of engine in order to find the best control. The BLDC engine must operate under various speed and load conditions with improved performance and robust and complex speed control. Because of this complexity, the traditional PID command encounters difficulties in controlling the speed of a BLDC. Another control technique is currently developing and is producing good results. This is the fuzzy controller that handles process control problems, that is, managing a process based on a given set point per action on the variables that describe the process. To achieve the desired results, the brushless DC machine model will be studied. With the model obtained, both types of regulator will be tested. A synthesis of the observed comparison results will enable a conclusion to be drawn on the performance of the two types of regulators driving a BLDC (Brushless DC).

On the Conversion of High-Frequency Soliton Solutions to a （1＋1）-Dimensional Nonlinear Partial Differential Evolution Equation

From the dynamical equation of barotropic relaxing media beneath pressure perturbations, and using the reductive perturbative analysis, we investigate the soliton structure of a （1＋1）-dimensional nonlinear partial differential evolution （NLPDE） equation δy（δη ＋ uδy ＋ （u^2/2）δy）u ＋ auy ＋ u = 0, describing high-frequency regime of perturbations. Thus, by means of Hirota＇s bilinearization method, three typical solutions depending strongly upon a characteristic dissipation parameter are unearthed.