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Multiobjective Optimization of Micro-Gas Turbines Environmental Polluting Emissions Due to their Internal and External Thermal Losses
Koffi N’guessan Marcellin,
Adama Ouattara,
Saraka Kouassi Joseph
Issue:
Volume 12, Issue 1, February 2023
Pages:
1-10
Received:
3 December 2022
Accepted:
28 December 2022
Published:
10 January 2023
Abstract: The ever-increasing demand for energy worldwide is hurting our environment, especially global warming. This is due to the significant use of fossil fuels. Faced with this situation, research and innovation actions are directed toward reducing these emissions by various scientific solutions including the multi-objective optimization of thermal machines. Among these thermal machines, one can mention the micro-gas turbines. Indeed, internal and external heat transfers are made in these machines because of their small size. These heat transfers contribute to degrading their performances in particular their environmental discharges that increase brutally. The present study aims at applying the eco-design methodology to these machines to evaluate their actual performances according to the heat transfers and to improve them. For this study, a thermodynamic model coupled with an environmental and economic model that describes the global behavior of micro-gas turbines has been performed. This model, operating in two modes adiabatic and polytropic to appreciate the deviations, gives good results that agree with those of the literature. The model was then optimized in a multi-objective way by Genetic Algorithms (NSGA IIb) giving a set of Pareto optimal solutions. The ideal solutions’ selection was done by applying the TOPSIS multi-criteria decision-making technique and gave the following results in polytropic operation: net power: 858.4 kW; global warming potential: 0.9561 kg CO2/kWh and the estimated production cost of US$4256/hr. This ideal solution was subsequently analyzed by OpenLCA software to evaluate the whole environmental impacts characterized mainly by HTP (kg C6H6/kWh): 0.356; EP (kg PO43-/kWh): 0.525; PCOP (kg C2H4/kWh): 0.295; AP (kg SO2/kWh): 0.356.
Abstract: The ever-increasing demand for energy worldwide is hurting our environment, especially global warming. This is due to the significant use of fossil fuels. Faced with this situation, research and innovation actions are directed toward reducing these emissions by various scientific solutions including the multi-objective optimization of thermal machi...
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Soil Reinforcement Methods for Environmental Protection of Slope Failure Against Landslides
Kempena Adolphe,
Obami Ondon Harmel,
Boudzoumou Florent,
Rafael Guardado Lacaba,
Antonio Olimpio Gonçalves
Issue:
Volume 12, Issue 1, February 2023
Pages:
11-17
Received:
8 December 2022
Accepted:
26 December 2022
Published:
10 January 2023
Abstract: Slopes are not stable due to the variations of slope gradient combined with the driving forces including the groundwater action, producing shear stresses in the slopes, which are contradicted by the soil shear strength. The slopes instability may cause the displacement of the mass of soil downstream recognised as landslide. Consequently, landslides are one of the most significant catastrophic phenomena observed on the earth surface. This phenomenon can be considered as a major concern on the social and economic point of view and for the quality of life of a local population, including also the environmental impact on the ground water level, blockage of rivers, road destruction, forests and ecosystems destruction, etc. Therefore, soil reinforcement has become one of the best forms of embankment protection against slopes failure. This work used soil reinforcement methods by using retaining structures, slope design with low gradient and vegetation cover to stabilize the embankment. The usage of the shear strength reduction technique was carried out to evaluate the stability of embankment slope. This process has tendency to reduce shear strength as rarer as failure is produced. This study is achieved along with pseudo-static and static methodologies. Varied parameters influence on the stability of slopes are revealed by accomplishment of many studies. To end, the Static method findings are acceded to comparison with the ones found by Pseudo-Static method. The results showed that the stability of reinforced slopes was reached and the slope can resist against landslides.
Abstract: Slopes are not stable due to the variations of slope gradient combined with the driving forces including the groundwater action, producing shear stresses in the slopes, which are contradicted by the soil shear strength. The slopes instability may cause the displacement of the mass of soil downstream recognised as landslide. Consequently, landslides...
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Copper Concentrations Found from Drinking Water, Soils, and Vegetables
Hlalanathi Gwanya,
Jennifer Laifa
Issue:
Volume 12, Issue 1, February 2023
Pages:
18-22
Received:
20 January 2022
Accepted:
16 June 2022
Published:
14 February 2023
Abstract: Humans, animals, and plants need copper for growth and development, but it can be an irritant to humans. The daily maximum limit of copper for humans is 10-12 µg day-1 and excess concentrations of copper can cause nausea, diarrhea, and anorexia. In plants, excess copper concentrations cause chlorosis, stunted growth, and denaturing of macromolecules. Only 10 mg kg-1 of copper can be accumulated by plants. The maximum allowable concentration in agricultural soils is 6.6 mg kg-1. The concentration of copper in drinking water should not exceed 1 mg L-1. When copper concentrations exceed an action level of 1.3 ppm in more than 10% of customer taps sampled, several additional controlling measures must be undertaken. In waste, the allowable concentration is 16 mg kg-1. The hypothesis of the study was that copper would be found in the vegetables grown from the agricultural soils. Cabbage, green pepper, spinach, and tomato were grown for thirteen weeks. The soil and vegetables were digested, and the copper concentrations were measured using an Atomic Absorption Spectroscopy (AAS). The highest total and extractable copper concentrations found in the soil were 73 mg kg-1 and 26 mg kg-1, respectively. More than 20 and 32 mg kg-1 of copper was found in the shoot and roots of the vegetables, respectively. More than 11 mg L-1 of copper was found in the tap water. The results indicated that the copper concentrations from the soil, water, and vegetables exceeded the allowable concentrations.
Abstract: Humans, animals, and plants need copper for growth and development, but it can be an irritant to humans. The daily maximum limit of copper for humans is 10-12 µg day-1 and excess concentrations of copper can cause nausea, diarrhea, and anorexia. In plants, excess copper concentrations cause chlorosis, stunted growth, and denaturing of macromolecule...
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Land Use Pattern Effect on Trace Metals Load and Quality of Soils: A Case Study of Lagos Municipal City
Majolagbe Abdulrafiu Olaiwola,
Awoyemi Kanyinsola Elizabeth,
Onwordi Chionyedua Teressa,
Olowu Rasak Adewale,
Oyewole Toyib Seun
Issue:
Volume 12, Issue 1, February 2023
Pages:
23-31
Received:
3 January 2023
Accepted:
6 February 2023
Published:
24 February 2023
Abstract: The quality of soil is influenced by natural activities: geological formations of an area and volume of water (rain), as well as anthropogenic events such as land use patterns. The patterns correlate with the trace metals load in an area. This study, thus, seeks to evaluate of the potentially toxic metals loads in both top and sub soils based on land use in the municipality of Lagos, using pollution indices. Six (6) composite samples collected from top and subsoils in five different land use areas: Industrial (Ikeja and Ilupeju), Coastal (Iyagbe and Badagry), Residential (Surulere and Yaba), Landfill (Abule Egba and Igando) and Agricultural areas (Fi, Niger and LASU road), were analyzed for trace metals employing standard method. Data obtained were subjected to pollution indices namely; Contamination Factor (CF) Enrichment Factor (EF), Geo Accumulation index (Igeo) and Pollution Load Index (PLI). The EF results showed minimal enrichment by iron (1.0) and lead (0.39), significant enrichment with zinc (8.9), and extremely high enrichment in respect of cadmium (95.5) and copper (524.3). The order of metals Cd > Cu > Fe > Zn > Pb is as revealed by Igeo while the order of PLI value of each area show the impact of land use; industrial (6.61) > landfill (6.40) > Residential (4.43) > Agricultural (3.30) > Coastal (2.67), indicating varying levels of deterioration of soils through anthropogenic sourced pollution. Measures must be implemented by the relevant agencies, to regularly monitor build-ups of metals and environmentally enlighten, ensuring sustainable environment in line with goal eleven (Sustainable cities and Communities) of Sustainable Development Goals.
Abstract: The quality of soil is influenced by natural activities: geological formations of an area and volume of water (rain), as well as anthropogenic events such as land use patterns. The patterns correlate with the trace metals load in an area. This study, thus, seeks to evaluate of the potentially toxic metals loads in both top and sub soils based on la...
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