The exploitation of groundwater by drilling in the Mitendi South-East district constitutes a solution to the water shortage in this peripheral part of the Mont-Ngafula township in Kinshasa, the capital of the DR Congo...The exploitation of groundwater by drilling in the Mitendi South-East district constitutes a solution to the water shortage in this peripheral part of the Mont-Ngafula township in Kinshasa, the capital of the DR Congo. Individuals exploit groundwater in boreholes to serve the population without taking into account certain necessary aspects such as the origin of the groundwater table and the quality which constitute the major problems of this work such as: What is the quantity of water from the recharge of our aquifer? What is the state of the Mitendi South-East aquifer water in relation to some physico-chemical parameters? The cardinal objective of this work is to provide chemical data and trace elements in each analyzed borehole and determine the type of recharge of the underground aquifer. The specific objectives are as follows: analyze the potability of groundwater on a physico-chemical level and their chemical facies, take the geographical coordinates of water samples from the aquifer in each targeted borehole in order to develop the sampling map of the area under study;also check each parameter analyzed in relation to WHO standards. We carried out a general investigation of the study area by carrying out observations, sampling and in-situ measurements of each borehole, as well as the good conservation of the samples taken in a cooler. The various measurements that we took in-situ: pH, electrical conductivity, turbidity, salinity, temperature, and TDS were carried out by using a multi-parameter probe in the laboratory of appropriate methods such as titled-sorting, spectrophotometry, atomic absorption spectrometry, ArcGise and Excel software. With regard to the results from laboratory analysis (physical and chemical analysis), the parameters showed that the standards recommended by the WHO were not respected. We affirm that the water consumed in the Mitendi South-East district in Mont-Ngafula town ship is not drinkable. Since, it can cause several water-borne diseases. It would be better to treat that water before being drunk. .展开更多
This study aims to characterize from a geotechnical point of view, the soils as well as the lateritic gravels along the Songololo-Lufu road route in the Kongo Central Province in the Democratic Republic of Congo (DRC)...This study aims to characterize from a geotechnical point of view, the soils as well as the lateritic gravels along the Songololo-Lufu road route in the Kongo Central Province in the Democratic Republic of Congo (DRC). Ten soil samples and eight lateritic gravel samples were analysed and tested in the laboratory. For each sample, identification parameters were determined such as particle size analysis, natural water content, Atterberg limits (plasticity index and consistency index), but also compaction and lift parameters such as optimal water content, maximum dry density and CBR lift index. All materials and soils have been classified according to the Congolese Road Standard (NRC) and according to the American HRB classification. The test results show us that clay soils almost always contain between 70% and 90% fine fraction;the grained fraction represents less than 30% in clay samples. For lateritic gravels soils, the percentage of fine elements varies between 35% and 15%;in sand around 20%;the gravelly fraction represents a little more than 50% of the soil. The majority of soil facies encountered define a plasticity index lower than 15. As for the consistency index, we obtained values greater than 1, both for clayey soils and for gravelly soils. The classification according to NRC defined for these soils the types Ae1 and Ae2 for the clayey facies and the types GL1 and GL2 for the gravelly soils, while that of the HRB identified the classes and subclasses A-6 and A-7-6 for clayey soils, and subclass A-2-6 for gravelly soils. The optimal water content values obtained range between 10.2% and 23.10%;the maximum dry densities are between 1.66 and 2.07 t/m<sup>3</sup> and the CBR index is between 6 and 26. As for the lateritic gravels materials of the Songololo region, the percentage of fine elements generally remains between 12% and 31%;the plasticity index is between 8 and 18;the optimal dry density is around 2 t/m<sup>3</sup>;the optimal water content is between 9.8% and 14.5% and the CBR index is between 27 and 82. The Songololo-Lufu lateritic gravels are characteristic of laterites in the savannah region, with a high gravel fraction at the expense of the fine fraction, but low parameters such as the liquid limit and plasticity index.展开更多
The size evolution of gold nanoparticles synthesized using tannic acid with initial gold chloride concentrations ranging from 0.2 - 2 mM at various tannic acid to chloroauric acid molar ratios (ranging from 2:1 to 12:...The size evolution of gold nanoparticles synthesized using tannic acid with initial gold chloride concentrations ranging from 0.2 - 2 mM at various tannic acid to chloroauric acid molar ratios (ranging from 2:1 to 12:1) has been analysed. Dynamic light scattering spectroscopic and tramission electron microscopic analyses were performed to assess the size of formed gold nanoparticles. Two different patterns of nanoparticle size evolution were obtained;the size evolution trend below 1 mM chloroauric acid concentration was found to be different from the one obtained at gold chloride concentrations higher than or equal to 1 mM. In case of sizes obtained for less than 1 mM gold chloride concentration, a general decrease in particle size was observed with increase in gold salt concentration. On the contrary, for the particles synthesised using chloroauric acid concentrations higher than or equal to 1 mM, with increase in gold salt concentration, a general increase in nanoparticle diameter was seen. For the molarities 0.2 and 0.5 mM, with increase in tannic acid/ chloroauric acid ratios, first the size decreases and then increases and finally reaches saturation. Particles formed at molarities greater than equal to 1 mM do not exhibit plateaux in their size rather initially decrease and then increase in response to increasing tannic acid/chloroauric acid ratios except for 2 mM concentration at which a small saturation is observed. The findings enumerate that higher gold chloride concentrations leave a significant impact on the sizes of gold nanaparticles obtained using tannic acid as a reducing agent of chloroauric acid solution.展开更多
This study focuses on the determination of physical and mechanical characteristics based on in vitro tests, by using field samples for the Kampemba urban area in the city of Lubumbashi. At the end of this study, we id...This study focuses on the determination of physical and mechanical characteristics based on in vitro tests, by using field samples for the Kampemba urban area in the city of Lubumbashi. At the end of this study, we identified the soils according to their parameters, and established the geotechnical classification by determining their bearing capacity by the group index method using from the identification tests carried out. By using the AASHTO classification method (American Association for State Highway Transportation Official), the results obtained after our studies revealed five classes of soil: A-2, A-4, A-5, A-6, A-7 in a general way, and particularly eight subgroups of soil: A-2-4, A-2-6, A-2-7, A-4, A-5, A-6, A-7-5 and A-7-6 for the concerned area. The latter has given statistical analysis and deep learning based on multi-layer perceptron, the global values of the physical parameters. It’s about: 31.77% ± 1.05% for the limit of liquidity;18.71% ± 0.76% for the plastic limit;13.06% ± 0.79% for the plasticity index;83.00% ± 3.33% for passing of 2 mm sieve;76.22% ± 3.2% for passing of 400 μm sieve;89.07% ± 2.99% for passing of 4.75 mm sieve;70.62% ± 2.39% passing of 80 μm sieve;1.66 ± 0.61 for the consistency index;<span style="white-space:nowrap;">−</span>0.67 ± 0.62 for the liquidity index and 8 ± 1 for the group index.展开更多
The rapid industrial development and population growth increase the utilization of fresh water resulting in an increase of the amount of wastewater. Several Countries face a double challenge with regard to water resou...The rapid industrial development and population growth increase the utilization of fresh water resulting in an increase of the amount of wastewater. Several Countries face a double challenge with regard to water resources, namely meeting the growing need for water for the population and treating the wastewater generated for application. The toxicity found in these water streams threatens the environment and human health. Hence the urgent need is to treat wastewater. The DRC is not immune from this threat. Its average population growth rate has exceeded the 3% and the number of industries it hosts continues to increase. The wastewater generated by this increasing pressure from urbanization and industrialization must be treated as required in the Congolese legal arsenal. Various factors need to be considered prior choosing the water treatment method. The choice must take into account the imperatives of the moment which are: modernization (local context) and sustainable development (international context). There are several wastewater treatments that are widely used for the removal of toxic elements such as ion exchange, reverse osmosis, chemical precipitation and electro-coagulation just to name a few. The most recent studies have shown that the galvanic technique can be used in the purification of water from domestic and industrial origin to meet drinking water standards. Various researchers have used this technique at laboratory and pilot scale demonstrating its cost-effectiveness as it uses no chemical reagents, consumes less energy and occupies only a small space for processing large flows. However, there are very few studies demonstrating the success of this treatment on an industrial scale. Therefore, this work seeks to understand and master the mechanisms that take place in the galvanic treatment. In addition, this study focuses on the development of a robust prototype that is adaptable to the needs of various users while at the same time being relatively cheap to meet the national needs.展开更多
The uptake of Cr(VI)from aqueous solutions was investigated using clinoptilolite and phillipsite rich tuffs.These minerals were modified using hexadecyltrimethyl-ammonium bromide(HDTMA-Br)and used for Cr(VI)ions remov...The uptake of Cr(VI)from aqueous solutions was investigated using clinoptilolite and phillipsite rich tuffs.These minerals were modified using hexadecyltrimethyl-ammonium bromide(HDTMA-Br)and used for Cr(VI)ions removal.The physicochemical characteristics of zeolitic minerals were revealed by XRD,XRF,BET and FT-IR techniques.The concentration of Cr(VI)working solutions,Cinit ranged between 5-100 mg·L-1,were prepared by dilution of the stock solution with distilled water with pHinit adjusted to the value of 3.0 or 4.0 or 5.0.The residual concentrations of chromium in the liquid samples were analyzed by ICP-OES.The uptake capacities of modified zeolites were compared in batch sorption experiments.The comparison of the obtained data identified that efficiency of Cr(VI)sorption onto clinoptilolite is always higher than in phillipsite case.The analysis of the infrared spectra revealed that after adsorption of Cr(VI)the characteristics for HDTMA vibrations were shifted in PHI-HDTMA case,while for CLI-HDTMA the intensity of characteristics peaks decreased.展开更多
The objective of this study was to determine the contamination of OCPs （organochlorine pesticides） in sediments from the upper middle of Sao Francisco River （Bahia, Brazil） in order to evaluate their potential pol...The objective of this study was to determine the contamination of OCPs （organochlorine pesticides） in sediments from the upper middle of Sao Francisco River （Bahia, Brazil） in order to evaluate their potential pollution risks. Samples of surface sediments were collected using a Petersen dredge at 21 stations located between Sobradinho and Cura^i. The organochlorine compounds analyzed were： p,p＇-DDT, p,p＇-DDD, p,p＇-DDE, dicofol, methoxychlor, HCHs, aldrin, endrin, endrin aldehyde, endrin ketone, dieldrin, heptachlor, heptachlor epoxide, endosulfan （ct, fl and sulfate） and chlordane （ct and ,/）. Extractions were carried out using the MAE （microwave-assisted extraction） method and organochlorine pesticides determination was achieved by GC/MS （gas chromatography-mass spectrometry）. Organochlorine concentrations ranged between 1.51-820.00 ng.gx, indicating very low to high levels. The most frequent OCPs were endrin aldehyde, -HCH, HCH, HCH, heptachlor and heptachlor epoxide.展开更多
This study aimed to optimize cross-sectional area of the extruder and the flow rate of the material through the extruder. Extrusion process was first modelized using the continuum mechanics method before being simulat...This study aimed to optimize cross-sectional area of the extruder and the flow rate of the material through the extruder. Extrusion process was first modelized using the continuum mechanics method before being simulated with the commercial software LS-DYNA using the Johnson-Cook model based on the finite element method after optimization of the factors with simplex algorithm. The study was carried out on a connecting rod: diameter of 145 mm, cross-section of 1.65 m<sup>2</sup>, length of 0.25 m, volume of 0.41 m<sup>3</sup> and a mass of 37 kg. Optimum parameters obtained were temperature of 850℃, flow rate of 0.237 m/s, die diameter of 19.2 mm, pin diameter of 14 mm, extrusion strength of 565.6 kN and press pressure of 245 GPa. From these factors, a blank was obtained with external and internal diameters of 19.2 and 14 mm respectively over a length of 28 m with a thickness of 2.6 mm. Simulation using LS-DYNA software resulted in a difference in values of 7.4% between optimization and simulation when the difference of 2.4% was found between modelling and simulation. These values make the process optimal for industrial application to improve the extrusion requirements of copper tubes.展开更多
The study focuses on the assessment of the surface water quality of the mining city of Kakanda (Lualaba Province in the DRC) to highlight pollution from mining activity. In addition to literature research, the identif...The study focuses on the assessment of the surface water quality of the mining city of Kakanda (Lualaba Province in the DRC) to highlight pollution from mining activity. In addition to literature research, the identification of mining activities and the location of rivers and streams, the methodology adopted consisted in analyzing the water upstream and downstream of different discharge points of final effluents. The choice of parameters was made according to the Congolese legislation on this subject. Field observations indicated that liquid effluents from mining plants are discharged into the natural environment through drains. Chemical analyses have shown that the waters of these drains are loaded with metals at concentrations tens of times higher than standards. The results of the physicochemical analyses also indicated a deterioration of the quality of the water downstream of the discharge points. The level of suspended solids reaches 182 mg/l for an acceptable level of 80 mg/l. The concentration of cobalt and manganese in the streams receiving the final effluents reaches, respectively, 0.659 mg/l and 1.709 mg/l for an acceptable threshold of 0.5 mg/l. The electrical conductivity, the chemical composition as well as the other parameters exploited have revealed pollution of mining origin.展开更多
The headrace of the Inga hydropower complex is experiencing siltation problems, reducing the exploitable draft and limiting the production capacity of the two main Inga hydropower plants during the low water period. D...The headrace of the Inga hydropower complex is experiencing siltation problems, reducing the exploitable draft and limiting the production capacity of the two main Inga hydropower plants during the low water period. During the 2019 low water period, several sediment slumps occurred in the Shongo basin, disrupting the production of hydroelectric power generated by the Inga 1 & 2 power plant, resulting in massive load shedding of power supply to downstream customers. The cardinal aim of this study is to determine the quantities of sediments deposited and those eroded, in order to know the evolution of sedimentation in the Shongo basin from February 2020 to May 2021. The results obtained show that the running index of the generating units is determinant and influences the sedimentation process in the Shongo basin. The cleaning of the Shongo basin in terms of the spatial distribution of sedimentation from February 2020 to May 2021 is plausible.展开更多
Fuzzy Logic is used to derive the optimal inventory policies in the Supply Chain (SC) numbers. We examine the performance of the optimal inventory policies by cutting the costs and increasing the supply chain manageme...Fuzzy Logic is used to derive the optimal inventory policies in the Supply Chain (SC) numbers. We examine the performance of the optimal inventory policies by cutting the costs and increasing the supply chain management efficiency. The proposed inventory policy uses multi-agent and Fuzzy logic, and provides managerial insights on the impact of the decision making in all the SC numbers. In particular, we focus on the way in which our agent purchases components using a mixed procurement strategy (combining long and short term planning) and how it sets its prices according to the prevailing market conditions and its own inventory level (because this adaptivity and flexibility are key to its success). In modern global market, one of the most important issues of the supply chain (SC) management is to satisfy changing customer demands and enterprises should enhance the long-term advantage through the optimal inventory control. In this paper an intelligent multi-agent system to simulate supply chain management has been developed.展开更多
Problems due to underground cavities at the level of soft and polymorphic sandstones, collapses and infiltration of acid waters through the fracture networks have been observed around the Kakobola hydroelectric develo...Problems due to underground cavities at the level of soft and polymorphic sandstones, collapses and infiltration of acid waters through the fracture networks have been observed around the Kakobola hydroelectric development, constituting potential risks for the stability of the dam. The objective of this article aims to highlight the major cause that can explain the generating processes of these cavities. Indeed, to do this, the exploration of the subsoil was made possible thanks to the eleven (11) boreholes drilled on the site, the determination of cavities by the method of colored tracers and the petrographic characterization using a microscope. The latter, by means of thin sections, reveals the presence of quartz arenites. The mineralogical characterization of rock materials was carried out using X-ray fluorescence and X-ray diffraction methods. X-ray fluorescence revealed the presence of nickel, zinc and iron. Diffraction shows us an abundance of silica, mainly quartz and its metastable phases, in particular tridymite and cristobalite. It also made it possible to question the presence of carbonated minerals. The drillings enabled us to elaborate the logs and to bring out a geological model of the sector of study. These models were produced on the basis of drilling and observations on excavation. These data also reveal the presence of underground cavities which were also confirmed by the colored tracer method. These cavities would be of natural origin due to the presence of carbonate minerals observed in the rocks and which are attacked by acidic waters attested by the pH 5 measurements of the waters of the Lufuku River. The infiltration of water in rocky materials of low density and through the various networks of fractures and cavities leads to instability of the rock and could damage the hydroelectric development.展开更多
The compensation circuit plays a crucial role in the framework of Capacitive Power Transfer(CPT)in wireless Electric Vehicle(EV)charging schemes.Various wireless charging factors such as power transfer capacity,effici...The compensation circuit plays a crucial role in the framework of Capacitive Power Transfer(CPT)in wireless Electric Vehicle(EV)charging schemes.Various wireless charging factors such as power transfer capacity,efficiency,and frequency depend on the design of compensation circuit topology.In CPT,power is transferred between the two capacitor plates(one transmitter plate embedded on the track and the other plate which is inserted in the wireless EV chassis operates as a receiver).The transmitter plate is excited by a high frequency source and power is transferred between the plates through an electric field.This review paper introduced an experimental prototype of the Corbin Sparrow(CS),featuring an onboard battery charger and an off-board DC charging port.Additionally,it presented a novel conformal bumper-based approach,highlighting its distinct advantages compared to alternative charging methods.The major challenges to employing capacitive technology in transferring power up to kW level are-the greater air gap between the capacitor of vehicle chassis&ground and the high value of electric field strength in the contour of plates.Also,due to the lowvalue of coupling capacitance,there is the requirement for suitable gain and compensated network which is a major area of concern.This review paper proposed various designs of compensation circuit topologies to achieve the effectiveness of the CPT scheme for Wireless Power Transfer(WPT)systems.展开更多
文摘The exploitation of groundwater by drilling in the Mitendi South-East district constitutes a solution to the water shortage in this peripheral part of the Mont-Ngafula township in Kinshasa, the capital of the DR Congo. Individuals exploit groundwater in boreholes to serve the population without taking into account certain necessary aspects such as the origin of the groundwater table and the quality which constitute the major problems of this work such as: What is the quantity of water from the recharge of our aquifer? What is the state of the Mitendi South-East aquifer water in relation to some physico-chemical parameters? The cardinal objective of this work is to provide chemical data and trace elements in each analyzed borehole and determine the type of recharge of the underground aquifer. The specific objectives are as follows: analyze the potability of groundwater on a physico-chemical level and their chemical facies, take the geographical coordinates of water samples from the aquifer in each targeted borehole in order to develop the sampling map of the area under study;also check each parameter analyzed in relation to WHO standards. We carried out a general investigation of the study area by carrying out observations, sampling and in-situ measurements of each borehole, as well as the good conservation of the samples taken in a cooler. The various measurements that we took in-situ: pH, electrical conductivity, turbidity, salinity, temperature, and TDS were carried out by using a multi-parameter probe in the laboratory of appropriate methods such as titled-sorting, spectrophotometry, atomic absorption spectrometry, ArcGise and Excel software. With regard to the results from laboratory analysis (physical and chemical analysis), the parameters showed that the standards recommended by the WHO were not respected. We affirm that the water consumed in the Mitendi South-East district in Mont-Ngafula town ship is not drinkable. Since, it can cause several water-borne diseases. It would be better to treat that water before being drunk. .
文摘This study aims to characterize from a geotechnical point of view, the soils as well as the lateritic gravels along the Songololo-Lufu road route in the Kongo Central Province in the Democratic Republic of Congo (DRC). Ten soil samples and eight lateritic gravel samples were analysed and tested in the laboratory. For each sample, identification parameters were determined such as particle size analysis, natural water content, Atterberg limits (plasticity index and consistency index), but also compaction and lift parameters such as optimal water content, maximum dry density and CBR lift index. All materials and soils have been classified according to the Congolese Road Standard (NRC) and according to the American HRB classification. The test results show us that clay soils almost always contain between 70% and 90% fine fraction;the grained fraction represents less than 30% in clay samples. For lateritic gravels soils, the percentage of fine elements varies between 35% and 15%;in sand around 20%;the gravelly fraction represents a little more than 50% of the soil. The majority of soil facies encountered define a plasticity index lower than 15. As for the consistency index, we obtained values greater than 1, both for clayey soils and for gravelly soils. The classification according to NRC defined for these soils the types Ae1 and Ae2 for the clayey facies and the types GL1 and GL2 for the gravelly soils, while that of the HRB identified the classes and subclasses A-6 and A-7-6 for clayey soils, and subclass A-2-6 for gravelly soils. The optimal water content values obtained range between 10.2% and 23.10%;the maximum dry densities are between 1.66 and 2.07 t/m<sup>3</sup> and the CBR index is between 6 and 26. As for the lateritic gravels materials of the Songololo region, the percentage of fine elements generally remains between 12% and 31%;the plasticity index is between 8 and 18;the optimal dry density is around 2 t/m<sup>3</sup>;the optimal water content is between 9.8% and 14.5% and the CBR index is between 27 and 82. The Songololo-Lufu lateritic gravels are characteristic of laterites in the savannah region, with a high gravel fraction at the expense of the fine fraction, but low parameters such as the liquid limit and plasticity index.
文摘The size evolution of gold nanoparticles synthesized using tannic acid with initial gold chloride concentrations ranging from 0.2 - 2 mM at various tannic acid to chloroauric acid molar ratios (ranging from 2:1 to 12:1) has been analysed. Dynamic light scattering spectroscopic and tramission electron microscopic analyses were performed to assess the size of formed gold nanoparticles. Two different patterns of nanoparticle size evolution were obtained;the size evolution trend below 1 mM chloroauric acid concentration was found to be different from the one obtained at gold chloride concentrations higher than or equal to 1 mM. In case of sizes obtained for less than 1 mM gold chloride concentration, a general decrease in particle size was observed with increase in gold salt concentration. On the contrary, for the particles synthesised using chloroauric acid concentrations higher than or equal to 1 mM, with increase in gold salt concentration, a general increase in nanoparticle diameter was seen. For the molarities 0.2 and 0.5 mM, with increase in tannic acid/ chloroauric acid ratios, first the size decreases and then increases and finally reaches saturation. Particles formed at molarities greater than equal to 1 mM do not exhibit plateaux in their size rather initially decrease and then increase in response to increasing tannic acid/chloroauric acid ratios except for 2 mM concentration at which a small saturation is observed. The findings enumerate that higher gold chloride concentrations leave a significant impact on the sizes of gold nanaparticles obtained using tannic acid as a reducing agent of chloroauric acid solution.
文摘This study focuses on the determination of physical and mechanical characteristics based on in vitro tests, by using field samples for the Kampemba urban area in the city of Lubumbashi. At the end of this study, we identified the soils according to their parameters, and established the geotechnical classification by determining their bearing capacity by the group index method using from the identification tests carried out. By using the AASHTO classification method (American Association for State Highway Transportation Official), the results obtained after our studies revealed five classes of soil: A-2, A-4, A-5, A-6, A-7 in a general way, and particularly eight subgroups of soil: A-2-4, A-2-6, A-2-7, A-4, A-5, A-6, A-7-5 and A-7-6 for the concerned area. The latter has given statistical analysis and deep learning based on multi-layer perceptron, the global values of the physical parameters. It’s about: 31.77% ± 1.05% for the limit of liquidity;18.71% ± 0.76% for the plastic limit;13.06% ± 0.79% for the plasticity index;83.00% ± 3.33% for passing of 2 mm sieve;76.22% ± 3.2% for passing of 400 μm sieve;89.07% ± 2.99% for passing of 4.75 mm sieve;70.62% ± 2.39% passing of 80 μm sieve;1.66 ± 0.61 for the consistency index;<span style="white-space:nowrap;">−</span>0.67 ± 0.62 for the liquidity index and 8 ± 1 for the group index.
文摘The rapid industrial development and population growth increase the utilization of fresh water resulting in an increase of the amount of wastewater. Several Countries face a double challenge with regard to water resources, namely meeting the growing need for water for the population and treating the wastewater generated for application. The toxicity found in these water streams threatens the environment and human health. Hence the urgent need is to treat wastewater. The DRC is not immune from this threat. Its average population growth rate has exceeded the 3% and the number of industries it hosts continues to increase. The wastewater generated by this increasing pressure from urbanization and industrialization must be treated as required in the Congolese legal arsenal. Various factors need to be considered prior choosing the water treatment method. The choice must take into account the imperatives of the moment which are: modernization (local context) and sustainable development (international context). There are several wastewater treatments that are widely used for the removal of toxic elements such as ion exchange, reverse osmosis, chemical precipitation and electro-coagulation just to name a few. The most recent studies have shown that the galvanic technique can be used in the purification of water from domestic and industrial origin to meet drinking water standards. Various researchers have used this technique at laboratory and pilot scale demonstrating its cost-effectiveness as it uses no chemical reagents, consumes less energy and occupies only a small space for processing large flows. However, there are very few studies demonstrating the success of this treatment on an industrial scale. Therefore, this work seeks to understand and master the mechanisms that take place in the galvanic treatment. In addition, this study focuses on the development of a robust prototype that is adaptable to the needs of various users while at the same time being relatively cheap to meet the national needs.
文摘The uptake of Cr(VI)from aqueous solutions was investigated using clinoptilolite and phillipsite rich tuffs.These minerals were modified using hexadecyltrimethyl-ammonium bromide(HDTMA-Br)and used for Cr(VI)ions removal.The physicochemical characteristics of zeolitic minerals were revealed by XRD,XRF,BET and FT-IR techniques.The concentration of Cr(VI)working solutions,Cinit ranged between 5-100 mg·L-1,were prepared by dilution of the stock solution with distilled water with pHinit adjusted to the value of 3.0 or 4.0 or 5.0.The residual concentrations of chromium in the liquid samples were analyzed by ICP-OES.The uptake capacities of modified zeolites were compared in batch sorption experiments.The comparison of the obtained data identified that efficiency of Cr(VI)sorption onto clinoptilolite is always higher than in phillipsite case.The analysis of the infrared spectra revealed that after adsorption of Cr(VI)the characteristics for HDTMA vibrations were shifted in PHI-HDTMA case,while for CLI-HDTMA the intensity of characteristics peaks decreased.
文摘The objective of this study was to determine the contamination of OCPs （organochlorine pesticides） in sediments from the upper middle of Sao Francisco River （Bahia, Brazil） in order to evaluate their potential pollution risks. Samples of surface sediments were collected using a Petersen dredge at 21 stations located between Sobradinho and Cura^i. The organochlorine compounds analyzed were： p,p＇-DDT, p,p＇-DDD, p,p＇-DDE, dicofol, methoxychlor, HCHs, aldrin, endrin, endrin aldehyde, endrin ketone, dieldrin, heptachlor, heptachlor epoxide, endosulfan （ct, fl and sulfate） and chlordane （ct and ,/）. Extractions were carried out using the MAE （microwave-assisted extraction） method and organochlorine pesticides determination was achieved by GC/MS （gas chromatography-mass spectrometry）. Organochlorine concentrations ranged between 1.51-820.00 ng.gx, indicating very low to high levels. The most frequent OCPs were endrin aldehyde, -HCH, HCH, HCH, heptachlor and heptachlor epoxide.
文摘This study aimed to optimize cross-sectional area of the extruder and the flow rate of the material through the extruder. Extrusion process was first modelized using the continuum mechanics method before being simulated with the commercial software LS-DYNA using the Johnson-Cook model based on the finite element method after optimization of the factors with simplex algorithm. The study was carried out on a connecting rod: diameter of 145 mm, cross-section of 1.65 m<sup>2</sup>, length of 0.25 m, volume of 0.41 m<sup>3</sup> and a mass of 37 kg. Optimum parameters obtained were temperature of 850℃, flow rate of 0.237 m/s, die diameter of 19.2 mm, pin diameter of 14 mm, extrusion strength of 565.6 kN and press pressure of 245 GPa. From these factors, a blank was obtained with external and internal diameters of 19.2 and 14 mm respectively over a length of 28 m with a thickness of 2.6 mm. Simulation using LS-DYNA software resulted in a difference in values of 7.4% between optimization and simulation when the difference of 2.4% was found between modelling and simulation. These values make the process optimal for industrial application to improve the extrusion requirements of copper tubes.
文摘The study focuses on the assessment of the surface water quality of the mining city of Kakanda (Lualaba Province in the DRC) to highlight pollution from mining activity. In addition to literature research, the identification of mining activities and the location of rivers and streams, the methodology adopted consisted in analyzing the water upstream and downstream of different discharge points of final effluents. The choice of parameters was made according to the Congolese legislation on this subject. Field observations indicated that liquid effluents from mining plants are discharged into the natural environment through drains. Chemical analyses have shown that the waters of these drains are loaded with metals at concentrations tens of times higher than standards. The results of the physicochemical analyses also indicated a deterioration of the quality of the water downstream of the discharge points. The level of suspended solids reaches 182 mg/l for an acceptable level of 80 mg/l. The concentration of cobalt and manganese in the streams receiving the final effluents reaches, respectively, 0.659 mg/l and 1.709 mg/l for an acceptable threshold of 0.5 mg/l. The electrical conductivity, the chemical composition as well as the other parameters exploited have revealed pollution of mining origin.
文摘The headrace of the Inga hydropower complex is experiencing siltation problems, reducing the exploitable draft and limiting the production capacity of the two main Inga hydropower plants during the low water period. During the 2019 low water period, several sediment slumps occurred in the Shongo basin, disrupting the production of hydroelectric power generated by the Inga 1 & 2 power plant, resulting in massive load shedding of power supply to downstream customers. The cardinal aim of this study is to determine the quantities of sediments deposited and those eroded, in order to know the evolution of sedimentation in the Shongo basin from February 2020 to May 2021. The results obtained show that the running index of the generating units is determinant and influences the sedimentation process in the Shongo basin. The cleaning of the Shongo basin in terms of the spatial distribution of sedimentation from February 2020 to May 2021 is plausible.
文摘Fuzzy Logic is used to derive the optimal inventory policies in the Supply Chain (SC) numbers. We examine the performance of the optimal inventory policies by cutting the costs and increasing the supply chain management efficiency. The proposed inventory policy uses multi-agent and Fuzzy logic, and provides managerial insights on the impact of the decision making in all the SC numbers. In particular, we focus on the way in which our agent purchases components using a mixed procurement strategy (combining long and short term planning) and how it sets its prices according to the prevailing market conditions and its own inventory level (because this adaptivity and flexibility are key to its success). In modern global market, one of the most important issues of the supply chain (SC) management is to satisfy changing customer demands and enterprises should enhance the long-term advantage through the optimal inventory control. In this paper an intelligent multi-agent system to simulate supply chain management has been developed.
文摘Problems due to underground cavities at the level of soft and polymorphic sandstones, collapses and infiltration of acid waters through the fracture networks have been observed around the Kakobola hydroelectric development, constituting potential risks for the stability of the dam. The objective of this article aims to highlight the major cause that can explain the generating processes of these cavities. Indeed, to do this, the exploration of the subsoil was made possible thanks to the eleven (11) boreholes drilled on the site, the determination of cavities by the method of colored tracers and the petrographic characterization using a microscope. The latter, by means of thin sections, reveals the presence of quartz arenites. The mineralogical characterization of rock materials was carried out using X-ray fluorescence and X-ray diffraction methods. X-ray fluorescence revealed the presence of nickel, zinc and iron. Diffraction shows us an abundance of silica, mainly quartz and its metastable phases, in particular tridymite and cristobalite. It also made it possible to question the presence of carbonated minerals. The drillings enabled us to elaborate the logs and to bring out a geological model of the sector of study. These models were produced on the basis of drilling and observations on excavation. These data also reveal the presence of underground cavities which were also confirmed by the colored tracer method. These cavities would be of natural origin due to the presence of carbonate minerals observed in the rocks and which are attacked by acidic waters attested by the pH 5 measurements of the waters of the Lufuku River. The infiltration of water in rocky materials of low density and through the various networks of fractures and cavities leads to instability of the rock and could damage the hydroelectric development.
文摘The compensation circuit plays a crucial role in the framework of Capacitive Power Transfer(CPT)in wireless Electric Vehicle(EV)charging schemes.Various wireless charging factors such as power transfer capacity,efficiency,and frequency depend on the design of compensation circuit topology.In CPT,power is transferred between the two capacitor plates(one transmitter plate embedded on the track and the other plate which is inserted in the wireless EV chassis operates as a receiver).The transmitter plate is excited by a high frequency source and power is transferred between the plates through an electric field.This review paper introduced an experimental prototype of the Corbin Sparrow(CS),featuring an onboard battery charger and an off-board DC charging port.Additionally,it presented a novel conformal bumper-based approach,highlighting its distinct advantages compared to alternative charging methods.The major challenges to employing capacitive technology in transferring power up to kW level are-the greater air gap between the capacitor of vehicle chassis&ground and the high value of electric field strength in the contour of plates.Also,due to the lowvalue of coupling capacitance,there is the requirement for suitable gain and compensated network which is a major area of concern.This review paper proposed various designs of compensation circuit topologies to achieve the effectiveness of the CPT scheme for Wireless Power Transfer(WPT)systems.
