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D Njopwouo - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of geopolymers from Volcanic Ash via the alkaline fusion method: Effect of Al2O3/Na2O molar ratio of soda–Volcanic Ash
Ceramics International, 2020Co-Authors: H. Kouamo Tchakoute, Antoine Elimbi, B Diffo B Kenne, J A Mbey, D NjopwouoAbstract:Abstract The alkaline fusion method was used to enhance the reactivity of Volcanic Ash for geopolymer synthesis. To that end, different mixtures of fused soda–Volcanic Ash (fused Volcanic Ash) were used to assess reactivity for geopolymer synthesis. The amount of amorphous phase was determined both in the Volcanic Ash and the fused Volcanic Ash and X-ray diffraction analysis was used to evaluate effect of the alkaline fusion method. Different geopolymer mortars were prepared by alkaline activation of mixtures of powders of fused Volcanic Ash and metakaolin and river sand using sodium silicate as activator. Metakaolin was considered as consumer of excess of alkali contained in the fused Volcanic Ash. The geopolymer mortars were characterized by determination of setting time, linear shrinkage, compressive strength and scanning electron microscopy. The amount of amorphous phase and excess of fused soda content of the fused Volcanic Ash depended on molar ratio of Al 2 O 3 /Na 2 O and played a key role for geopolymer synthesis. The most convenient Al 2 O 3 /Na 2 O molar ratio of fused Volcanic Ash to produce effective geopolymer mortars ranged between 0.13 and 0.18. This study showed that Volcanic Ash can be used successfully as an alternative raw material for production of geopolymers via alkaline activation of fused Volcanic Ash.
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Synthesis of Volcanic Ash-based geopolymer mortars by fusion method: Effects of adding metakaolin to fused Volcanic Ash
Ceramics International, 2013Co-Authors: H. Tchakoute Kouamo, Antoine Elimbi, J A Mbey, B.b. Kenne Diffo, D NjopwouoAbstract:Abstract The present study aimed at improving the properties of geopolymer mortars obtained from Volcanic Ash as a source material. An alkali fusion process was used to promote the dissolution of Si and Al species from the Volcanic Ash and thus to enhance the reactivity of Volcanic Ash. Various amount of metakaolin (30%, 40%, 50% and 60% MK by weight) was used to consume the excess alkali needed for the fusion. The amount of amorphous phase was determined both in the Volcanic Ash and the fused Volcanic Ash and X-ray diffraction analysis was used to evaluate effect of the alkaline fusion method. Geopolymers were prepared by alkali activation of mixtures of powders of fused Volcanic Ash, various amount of metakaolin and river sand using a sodium silicate solution as activator. The geopolymer mortars were characterized by determination of setting time, linear shrinkage, scanning electron microscopy and compressive strength. The results of this study indicate that geopolymer mortars synthesized by the fusion method exhibit low setting time (7–15 min), low shrinkage (0–0.42%) and high compressive strength (41.5–68.8 MPa). This study showed that, by enhancing the reactivity of Volcanic Ash by alkali fusion and balancing the Na/Al ratio through the addition of metakaolin, all Volcanic Ashes can be recycled as an alternative source material for the production of geopolymers.
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synthesis of geopolymers from Volcanic Ash via the alkaline fusion method effect of al2o3 na2o molar ratio of soda Volcanic Ash
Ceramics International, 2013Co-Authors: Kouamo H Tchakoute, Antoine Elimbi, B Diffo B Kenne, J A Mbey, D NjopwouoAbstract:Abstract The alkaline fusion method was used to enhance the reactivity of Volcanic Ash for geopolymer synthesis. To that end, different mixtures of fused soda–Volcanic Ash (fused Volcanic Ash) were used to assess reactivity for geopolymer synthesis. The amount of amorphous phase was determined both in the Volcanic Ash and the fused Volcanic Ash and X-ray diffraction analysis was used to evaluate effect of the alkaline fusion method. Different geopolymer mortars were prepared by alkaline activation of mixtures of powders of fused Volcanic Ash and metakaolin and river sand using sodium silicate as activator. Metakaolin was considered as consumer of excess of alkali contained in the fused Volcanic Ash. The geopolymer mortars were characterized by determination of setting time, linear shrinkage, compressive strength and scanning electron microscopy. The amount of amorphous phase and excess of fused soda content of the fused Volcanic Ash depended on molar ratio of Al 2 O 3 /Na 2 O and played a key role for geopolymer synthesis. The most convenient Al 2 O 3 /Na 2 O molar ratio of fused Volcanic Ash to produce effective geopolymer mortars ranged between 0.13 and 0.18. This study showed that Volcanic Ash can be used successfully as an alternative raw material for production of geopolymers via alkaline activation of fused Volcanic Ash.
J A Mbey - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of geopolymers from Volcanic Ash via the alkaline fusion method: Effect of Al2O3/Na2O molar ratio of soda–Volcanic Ash
Ceramics International, 2020Co-Authors: H. Kouamo Tchakoute, Antoine Elimbi, B Diffo B Kenne, J A Mbey, D NjopwouoAbstract:Abstract The alkaline fusion method was used to enhance the reactivity of Volcanic Ash for geopolymer synthesis. To that end, different mixtures of fused soda–Volcanic Ash (fused Volcanic Ash) were used to assess reactivity for geopolymer synthesis. The amount of amorphous phase was determined both in the Volcanic Ash and the fused Volcanic Ash and X-ray diffraction analysis was used to evaluate effect of the alkaline fusion method. Different geopolymer mortars were prepared by alkaline activation of mixtures of powders of fused Volcanic Ash and metakaolin and river sand using sodium silicate as activator. Metakaolin was considered as consumer of excess of alkali contained in the fused Volcanic Ash. The geopolymer mortars were characterized by determination of setting time, linear shrinkage, compressive strength and scanning electron microscopy. The amount of amorphous phase and excess of fused soda content of the fused Volcanic Ash depended on molar ratio of Al 2 O 3 /Na 2 O and played a key role for geopolymer synthesis. The most convenient Al 2 O 3 /Na 2 O molar ratio of fused Volcanic Ash to produce effective geopolymer mortars ranged between 0.13 and 0.18. This study showed that Volcanic Ash can be used successfully as an alternative raw material for production of geopolymers via alkaline activation of fused Volcanic Ash.
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Synthesis of Volcanic Ash-based geopolymer mortars by fusion method: Effects of adding metakaolin to fused Volcanic Ash
Ceramics International, 2013Co-Authors: H. Tchakoute Kouamo, Antoine Elimbi, J A Mbey, B.b. Kenne Diffo, D NjopwouoAbstract:Abstract The present study aimed at improving the properties of geopolymer mortars obtained from Volcanic Ash as a source material. An alkali fusion process was used to promote the dissolution of Si and Al species from the Volcanic Ash and thus to enhance the reactivity of Volcanic Ash. Various amount of metakaolin (30%, 40%, 50% and 60% MK by weight) was used to consume the excess alkali needed for the fusion. The amount of amorphous phase was determined both in the Volcanic Ash and the fused Volcanic Ash and X-ray diffraction analysis was used to evaluate effect of the alkaline fusion method. Geopolymers were prepared by alkali activation of mixtures of powders of fused Volcanic Ash, various amount of metakaolin and river sand using a sodium silicate solution as activator. The geopolymer mortars were characterized by determination of setting time, linear shrinkage, scanning electron microscopy and compressive strength. The results of this study indicate that geopolymer mortars synthesized by the fusion method exhibit low setting time (7–15 min), low shrinkage (0–0.42%) and high compressive strength (41.5–68.8 MPa). This study showed that, by enhancing the reactivity of Volcanic Ash by alkali fusion and balancing the Na/Al ratio through the addition of metakaolin, all Volcanic Ashes can be recycled as an alternative source material for the production of geopolymers.
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synthesis of geopolymers from Volcanic Ash via the alkaline fusion method effect of al2o3 na2o molar ratio of soda Volcanic Ash
Ceramics International, 2013Co-Authors: Kouamo H Tchakoute, Antoine Elimbi, B Diffo B Kenne, J A Mbey, D NjopwouoAbstract:Abstract The alkaline fusion method was used to enhance the reactivity of Volcanic Ash for geopolymer synthesis. To that end, different mixtures of fused soda–Volcanic Ash (fused Volcanic Ash) were used to assess reactivity for geopolymer synthesis. The amount of amorphous phase was determined both in the Volcanic Ash and the fused Volcanic Ash and X-ray diffraction analysis was used to evaluate effect of the alkaline fusion method. Different geopolymer mortars were prepared by alkaline activation of mixtures of powders of fused Volcanic Ash and metakaolin and river sand using sodium silicate as activator. Metakaolin was considered as consumer of excess of alkali contained in the fused Volcanic Ash. The geopolymer mortars were characterized by determination of setting time, linear shrinkage, compressive strength and scanning electron microscopy. The amount of amorphous phase and excess of fused soda content of the fused Volcanic Ash depended on molar ratio of Al 2 O 3 /Na 2 O and played a key role for geopolymer synthesis. The most convenient Al 2 O 3 /Na 2 O molar ratio of fused Volcanic Ash to produce effective geopolymer mortars ranged between 0.13 and 0.18. This study showed that Volcanic Ash can be used successfully as an alternative raw material for production of geopolymers via alkaline activation of fused Volcanic Ash.
Junjuan Zhao - One of the best experts on this subject based on the ideXlab platform.
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REMOTE SENSING DETECTION OF Volcanic Ash CLOUD USING INDEPENDENT COMPONENT ANALYSIS
Seismology and Geology, 2020Co-Authors: Chengfan Li, Junjuan Zhao, Shi-qiang ZhouAbstract:The Volcanic Ash cloud is mainly composed of Volcanic Ash debris and gases. The adequate mixture of the two can form acidic aerosols. It not only causes the major global climate and environmental changes,but also seriously threatens the aviation safety. Remote sensing can quickly and accurately obtain the information of the surface's and the atmosphere's changes; therefore it is playing an important role in the monitoring of Volcanic activity. In recent years,with the advancement of sensor technology,the thermal infrared remote sensing technology has become an important means of detecting the Volcanic Ash cloud. However,due to the large amount of spectral bands and data,the remote sensing data have pretty strong band correlation and obvious information redundancy problem, all of which have decreased to a certain degree the detecting accuracy of Volcanic Ash cloud. Therefore,it is necessary to introduce new data processing methods into the Volcanic Ash cloud remote sensing detection field. Principal component analysis(PCA)can compress a large number of complex information effectively into a few principal components; as a result,it is widely applied in the data compression and hyperspectral remote sensing field. Independent component analysis(ICA)is a recently developed new data processing method which can linearly decompose the observed data into mutually dependent components,and achieve the decorrelation and redundancy elimination of remote sensing data; so it has certain potential in Volcanic Ash cloud detection. A remote sensing detecting algorithm of Volcanic Ash cloud,which uses ICA method,is proposed after the exploration of the physics and chemical properties of Volcanic Ash cloud. This paper takes the MODIS remote sensing image of Iceland's Eyjafjallajokull Volcanic Ash cloud on April 19,2010 as data source. It uses ICA in Volcanic Ash cloud detection on the basis of the principal component analysis(PCA)processing of MODIS image,and gives comparison among these following parties: the detected results,the relevant research results, United States Geological Survey(USGS)standard spectral database and SO2 concentration distribution. The results show that: ICA can successfully obtain the information of the Volcanic Ash cloud from MODIS image; the detected Volcanic Ash cloud has a good consistency with the USGS standard spectral database and the SO2concentration distribution,thus,it can obtain pretty good detection results.
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Classification of Volcanic Ash cloud based on sensitivity analysis and FCM
2017 IEEE 2nd Advanced Information Technology Electronic and Automation Control Conference (IAEAC), 2017Co-Authors: Chengfan Li, Junjuan Zhao, Yuan YuanAbstract:Volcanic Ash cloud identification is a difficult issue in the classification of remote sensing image, and the accurate classification of Volcanic Ash cloud from remote sensing image has become a critical issue of volcano monitoring and aviation safety application. Aiming at the characteristics of remote sensing images and fuzzy C-means clustering (FCM) algorithm, a combined remote sensing classification method of Volcanic Ash cloud based on sensitivity analysis and FCM in which a two-dimensional spectral feature space was constructed and the pixels were further classified and clustered, has been proposed in this paper, and the cluster application experiments have been further tested with moderate resolution imaging spectroradiometer (MODIS) images. The experiment results show that the method proposed can classify some small areas of Volcanic Ash cloud, the classification accuracy and Kappa coefficient reached 86.8% and 0.7845 respectively, and achieved good classification effect of Volcanic Ash cloud.
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A New Fuzzy Clustering Method With Neighborhood Distance Constraint for Volcanic Ash Cloud
IEEE Access, 2016Co-Authors: Chengfan Li, Junjuan ZhaoAbstract:Remote sensing classification for Volcanic Ash cloud is a difficult task in the remote sensing application, and how to accurately obtain the Volcanic Ash cloud information from remote sensing image has become a key step in remote sensing classification of Volcanic Ash cloud. Aiming at the characteristics of the remote sensing images, via introducing the neighborhood pixels based on the classical fuzzy C-means clustering algorithm, this paper proposed a new fuzzy clustering remote sensing classification method with neighborhood distance constraint for Volcanic Ash cloud. This paper is tested from simulation texture image and moderate resolution imaging spectroradiometer remote sensing image, and finally explored the Sangeang Api Volcanic Ash cloud case on May 30, 2014. Our experiments show that the proposed method can effectively classify the Volcanic Ash cloud from remote sensing images, and the overall classification accuracy and Kappa coefficient reach 88.4% and 0.8064. To some extent, it overcomes the deficiency of the approaches in traditional Volcanic Ash cloud remote sensing classification.
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A New Detection Method of Volcanic Ash Cloud Based on MODIS Image
Journal of The Indian Society of Remote Sensing, 2014Co-Authors: Jiangshan Dong, Chengfan Li, Junjuan ZhaoAbstract:The Volcanic Ash can affect the global climate changes and aviation safety, and has become a hot topic for public security research. The satellite remote sensing sensor can quickly and accurately obtain the Volcanic Ash cloud information. However, the satellite image has pretty strong inter-band correlation and data redundancy. Principal component analysis (PCA) can overcome the inter-band correlation and data redundancy of satellite images and compress a large number of complex information effectively into a few principal components. Taking the Eyjafjallajokull Volcanic Ash cloud formed on 19 April 2010 for example, in this paper, the PCA method is used to detect the Volcanic Ash cloud based on moderate resolution imaging spectroradiometer (MODIS) image. The results show that: the PCA method can obtain the Volcanic Ash cloud from MODIS image; it is much simpler and the detected Volcanic Ash cloud has a good consistency with the previous research on the basis of spatial distribution and SO2 concentration.
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Diffusion Source Detection of Volcanic Ash Cloud Using MODIS Satellite Data
Journal of The Indian Society of Remote Sensing, 2014Co-Authors: Chengfan Li, Junjuan Zhao, Shi-qiang ZhouAbstract:The massive Volcanic Ash cloud not only causes obvious global climate and environmental changes, but also threatens aviation safety under the background of globalization. The diffusion source detection is a key factor in the Volcanic Ash cloud monitoring and the diffusion research. Taking the Eyjafjallajokull’s Volcanic Ash cloud on April 19, 2010 in Iceland as an example, based on the analysis of the absorption spectrum characteristics in the thermal infrared spectral range, in this paper, a new diffusion source detection algorithm of Volcanic Ash cloud combining split window algorithm with SO2 concentration distribution is proposed from the moderate resolution imaging spectroradiometer (MODIS) satellite remote sensing images; subsequently the Ash radiance index (ARI) and absorbing aerosol index (AAI) are applied as contrast to the detection results. The results show that the proposed algorithm can effectively detect the diffusion source of Volcanic Ash cloud, and has high consistency with the ARI and AAI distributions, and has certain potential applications in improving the detection effect of Volcanic Ash cloud and prediction accuracy of diffusion model.
Antoine Elimbi - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of geopolymers from Volcanic Ash via the alkaline fusion method: Effect of Al2O3/Na2O molar ratio of soda–Volcanic Ash
Ceramics International, 2020Co-Authors: H. Kouamo Tchakoute, Antoine Elimbi, B Diffo B Kenne, J A Mbey, D NjopwouoAbstract:Abstract The alkaline fusion method was used to enhance the reactivity of Volcanic Ash for geopolymer synthesis. To that end, different mixtures of fused soda–Volcanic Ash (fused Volcanic Ash) were used to assess reactivity for geopolymer synthesis. The amount of amorphous phase was determined both in the Volcanic Ash and the fused Volcanic Ash and X-ray diffraction analysis was used to evaluate effect of the alkaline fusion method. Different geopolymer mortars were prepared by alkaline activation of mixtures of powders of fused Volcanic Ash and metakaolin and river sand using sodium silicate as activator. Metakaolin was considered as consumer of excess of alkali contained in the fused Volcanic Ash. The geopolymer mortars were characterized by determination of setting time, linear shrinkage, compressive strength and scanning electron microscopy. The amount of amorphous phase and excess of fused soda content of the fused Volcanic Ash depended on molar ratio of Al 2 O 3 /Na 2 O and played a key role for geopolymer synthesis. The most convenient Al 2 O 3 /Na 2 O molar ratio of fused Volcanic Ash to produce effective geopolymer mortars ranged between 0.13 and 0.18. This study showed that Volcanic Ash can be used successfully as an alternative raw material for production of geopolymers via alkaline activation of fused Volcanic Ash.
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Synthesis of Volcanic Ash-based geopolymer mortars by fusion method: Effects of adding metakaolin to fused Volcanic Ash
Ceramics International, 2013Co-Authors: H. Tchakoute Kouamo, Antoine Elimbi, J A Mbey, B.b. Kenne Diffo, D NjopwouoAbstract:Abstract The present study aimed at improving the properties of geopolymer mortars obtained from Volcanic Ash as a source material. An alkali fusion process was used to promote the dissolution of Si and Al species from the Volcanic Ash and thus to enhance the reactivity of Volcanic Ash. Various amount of metakaolin (30%, 40%, 50% and 60% MK by weight) was used to consume the excess alkali needed for the fusion. The amount of amorphous phase was determined both in the Volcanic Ash and the fused Volcanic Ash and X-ray diffraction analysis was used to evaluate effect of the alkaline fusion method. Geopolymers were prepared by alkali activation of mixtures of powders of fused Volcanic Ash, various amount of metakaolin and river sand using a sodium silicate solution as activator. The geopolymer mortars were characterized by determination of setting time, linear shrinkage, scanning electron microscopy and compressive strength. The results of this study indicate that geopolymer mortars synthesized by the fusion method exhibit low setting time (7–15 min), low shrinkage (0–0.42%) and high compressive strength (41.5–68.8 MPa). This study showed that, by enhancing the reactivity of Volcanic Ash by alkali fusion and balancing the Na/Al ratio through the addition of metakaolin, all Volcanic Ashes can be recycled as an alternative source material for the production of geopolymers.
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synthesis of geopolymers from Volcanic Ash via the alkaline fusion method effect of al2o3 na2o molar ratio of soda Volcanic Ash
Ceramics International, 2013Co-Authors: Kouamo H Tchakoute, Antoine Elimbi, B Diffo B Kenne, J A Mbey, D NjopwouoAbstract:Abstract The alkaline fusion method was used to enhance the reactivity of Volcanic Ash for geopolymer synthesis. To that end, different mixtures of fused soda–Volcanic Ash (fused Volcanic Ash) were used to assess reactivity for geopolymer synthesis. The amount of amorphous phase was determined both in the Volcanic Ash and the fused Volcanic Ash and X-ray diffraction analysis was used to evaluate effect of the alkaline fusion method. Different geopolymer mortars were prepared by alkaline activation of mixtures of powders of fused Volcanic Ash and metakaolin and river sand using sodium silicate as activator. Metakaolin was considered as consumer of excess of alkali contained in the fused Volcanic Ash. The geopolymer mortars were characterized by determination of setting time, linear shrinkage, compressive strength and scanning electron microscopy. The amount of amorphous phase and excess of fused soda content of the fused Volcanic Ash depended on molar ratio of Al 2 O 3 /Na 2 O and played a key role for geopolymer synthesis. The most convenient Al 2 O 3 /Na 2 O molar ratio of fused Volcanic Ash to produce effective geopolymer mortars ranged between 0.13 and 0.18. This study showed that Volcanic Ash can be used successfully as an alternative raw material for production of geopolymers via alkaline activation of fused Volcanic Ash.
Kouamo H Tchakoute - One of the best experts on this subject based on the ideXlab platform.
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synthesis of geopolymers from Volcanic Ash via the alkaline fusion method effect of al2o3 na2o molar ratio of soda Volcanic Ash
Ceramics International, 2013Co-Authors: Kouamo H Tchakoute, Antoine Elimbi, B Diffo B Kenne, J A Mbey, D NjopwouoAbstract:Abstract The alkaline fusion method was used to enhance the reactivity of Volcanic Ash for geopolymer synthesis. To that end, different mixtures of fused soda–Volcanic Ash (fused Volcanic Ash) were used to assess reactivity for geopolymer synthesis. The amount of amorphous phase was determined both in the Volcanic Ash and the fused Volcanic Ash and X-ray diffraction analysis was used to evaluate effect of the alkaline fusion method. Different geopolymer mortars were prepared by alkaline activation of mixtures of powders of fused Volcanic Ash and metakaolin and river sand using sodium silicate as activator. Metakaolin was considered as consumer of excess of alkali contained in the fused Volcanic Ash. The geopolymer mortars were characterized by determination of setting time, linear shrinkage, compressive strength and scanning electron microscopy. The amount of amorphous phase and excess of fused soda content of the fused Volcanic Ash depended on molar ratio of Al 2 O 3 /Na 2 O and played a key role for geopolymer synthesis. The most convenient Al 2 O 3 /Na 2 O molar ratio of fused Volcanic Ash to produce effective geopolymer mortars ranged between 0.13 and 0.18. This study showed that Volcanic Ash can be used successfully as an alternative raw material for production of geopolymers via alkaline activation of fused Volcanic Ash.
