Olusola Johnson Ojo, Suraju Adesina Adepoju, Ayodeji Awe, Adeonipekun Dele Adedoyin, Sikiru Ottan Abdulraman, Busoye Thomas Omoyajowo
This study is focused on the evaluation of the geophagic characteristics of the sedimentary clay deposits at Share and Tshonga areas, northern Bida Basin, Nigeria. The methods used include particle size distribution, cation exchange capacity (CEC), acidity and alkalinity (pH), X-ray diffractometry, and bulk inorganic geochemical analysis (X-ray fluorescence and inductively coupled plasma mass spectrophotometer). The investigated clays are classified as dominantly clayey–silt with minor clayey–sand type, which conforms with the textural standard of geophagic clays obtained from different parts of the world. The whitish coloration of the clays with an occasional red stain also compares well with geophagic clays from Kenya and parts of South Africa and is therefore considered suitable for consumption. The observed low CEC (1.71–5.06 cmol(+)/kg) and acidic pH (4.54–6.87) values of the clay samples would make them effective against nausea and excessive salivation during pregnancy. The mineralogical compositions of these clay samples show the dominance of kaolinite with minor non-clay minerals, which makes it suitable not only for food detoxification but also as an alleviation of gastrointestinal disorders such as diarrhea. Chemical analysis shows a low percentage per weight of certain elements that are of nutritional value, though not in the present state but better as excipients in the pharmaceutical industry. It was observed, however, that consumption of more of the studied clay may lead to adverse health due to the presence of some heavy metals (Co, Cu, Ni, Cd, Ag, and Pb) with concentrations in excess of the permissible limit.
{"title":"Physicochemical and mineralogical composition studies of clays from Share and Tshonga areas, Northern Bida Basin, Nigeria: Implications for Geophagia","authors":"Olusola Johnson Ojo, Suraju Adesina Adepoju, Ayodeji Awe, Adeonipekun Dele Adedoyin, Sikiru Ottan Abdulraman, Busoye Thomas Omoyajowo","doi":"10.1515/geo-2022-0507","DOIUrl":"https://doi.org/10.1515/geo-2022-0507","url":null,"abstract":"This study is focused on the evaluation of the geophagic characteristics of the sedimentary clay deposits at Share and Tshonga areas, northern Bida Basin, Nigeria. The methods used include particle size distribution, cation exchange capacity (CEC), acidity and alkalinity (pH), X-ray diffractometry, and bulk inorganic geochemical analysis (X-ray fluorescence and inductively coupled plasma mass spectrophotometer). The investigated clays are classified as dominantly clayey–silt with minor clayey–sand type, which conforms with the textural standard of geophagic clays obtained from different parts of the world. The whitish coloration of the clays with an occasional red stain also compares well with geophagic clays from Kenya and parts of South Africa and is therefore considered suitable for consumption. The observed low CEC (1.71–5.06 cmol(+)/kg) and acidic pH (4.54–6.87) values of the clay samples would make them effective against nausea and excessive salivation during pregnancy. The mineralogical compositions of these clay samples show the dominance of kaolinite with minor non-clay minerals, which makes it suitable not only for food detoxification but also as an alleviation of gastrointestinal disorders such as diarrhea. Chemical analysis shows a low percentage per weight of certain elements that are of nutritional value, though not in the present state but better as excipients in the pharmaceutical industry. It was observed, however, that consumption of more of the studied clay may lead to adverse health due to the presence of some heavy metals (Co, Cu, Ni, Cd, Ag, and Pb) with concentrations in excess of the permissible limit.","PeriodicalId":48712,"journal":{"name":"Open Geosciences","volume":"10 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141614494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shuguang Lu, Li Wu, Houchun Guan, Xiaosi Hu, Baodong Yang, Wenjing Luo, Ziyi Xu, Yang Zhang, Boshi Liu, Wentian Cai
Chaohu Lake is a representative lake in China that suffers from severe eutrophication and algal blooms. Understanding the changes in the lake’s eutrophic condition over time is essential for its restoration and management under the background of global changes and regional sustainability. In this context, the compositions of carbon and nitrogen isotopes (δ13Corg and δ15N, respectively), total organic carbon (TOC), total nitrogen (TN), and carbon–nitrogen ratio (C/N) were analysed to depict the history of eutrophic state of Chaohu Lake, and its relationship with environmental changes. The result show that before the 1950s, the primary productivity of the lake was low. During the period from the 1950s to the 1970s, primary productivity increased substantially due to eutrophication. From the 1970s to the present, as a result of the construction of the Chaohu Floodgate Station, water replacement in the semi-closed Chaohu Lake gradually slowed and nutrients began to accumulate more rapidly. These conditions led to enhanced lake productivity and rapid eutrophication, mainly caused by intensified human activities and increased exogenous inputs. Our findings suggest that the geochemical records (δ13Corg, δ15N, TOC, TN, and C/N ratios) in sediment for Chaohu Lake are capable of recording important shifts in the temporal evolution of lake-water trophic state.
{"title":"Geochemical sedimentary records of eutrophication and environmental change in Chaohu Lake, East China","authors":"Shuguang Lu, Li Wu, Houchun Guan, Xiaosi Hu, Baodong Yang, Wenjing Luo, Ziyi Xu, Yang Zhang, Boshi Liu, Wentian Cai","doi":"10.1515/geo-2022-0649","DOIUrl":"https://doi.org/10.1515/geo-2022-0649","url":null,"abstract":"Chaohu Lake is a representative lake in China that suffers from severe eutrophication and algal blooms. Understanding the changes in the lake’s eutrophic condition over time is essential for its restoration and management under the background of global changes and regional sustainability. In this context, the compositions of carbon and nitrogen isotopes (<jats:italic>δ</jats:italic> <jats:sup>13</jats:sup>C<jats:sub>org</jats:sub> and <jats:italic>δ</jats:italic> <jats:sup>15</jats:sup>N, respectively), total organic carbon (TOC), total nitrogen (TN), and carbon–nitrogen ratio (C/N) were analysed to depict the history of eutrophic state of Chaohu Lake, and its relationship with environmental changes. The result show that before the 1950s, the primary productivity of the lake was low. During the period from the 1950s to the 1970s, primary productivity increased substantially due to eutrophication. From the 1970s to the present, as a result of the construction of the Chaohu Floodgate Station, water replacement in the semi-closed Chaohu Lake gradually slowed and nutrients began to accumulate more rapidly. These conditions led to enhanced lake productivity and rapid eutrophication, mainly caused by intensified human activities and increased exogenous inputs. Our findings suggest that the geochemical records (<jats:italic>δ</jats:italic> <jats:sup>13</jats:sup>C<jats:sub>org</jats:sub>, <jats:italic>δ</jats:italic> <jats:sup>15</jats:sup>N, TOC, TN, and C/N ratios) in sediment for Chaohu Lake are capable of recording important shifts in the temporal evolution of lake-water trophic state.","PeriodicalId":48712,"journal":{"name":"Open Geosciences","volume":"29 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141615051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rocky desertification is a pressing environmental concern in Southwest China, and it significantly impacts local living conditions and regional sustainability. Employing remote sensing on a macro scale, this study focuses on identifying and analyzing the spatial distribution and driving factors of rocky desertification. Conducted in Southwest China, using Landsat data from Google Earth Engine, the research quantitatively extracts information on rocky desertification patches through spectral analysis methods. We investigated the spatial distribution characteristics and driving factors of rocky desertification through geographic information system spatial analysis and a geodetector model. The main conclusions are as follows. The area of rocky desertification in Southwest China covers 217530.4 km² (accounting for 15.6% of Southwest China), with areas of slight, moderate, and severe rocky desertification at 81.3, 7.1, and 11.6%, respectively. Spatially, rocky desertification is primarily distributed in areas where lithology is carbonate rock between clastic rocks and continuous limestone, slope exceeds 15°, elevation range is 1,000–2,000 m, land use types are grassland and woodland, precipitation is 80–120 mm, and population density is below 50 people/km². Human activities have a minimal influence in comparison to natural factors. Geodetector analysis identifies lithology, land use types, and slope as primary driving factors, with interactive effects of lithology and land use type and slope and land use type jointly influencing rocky desertification formation in Southwest China. The results of the study provide a scientific basis for an in-depth understanding of rocky desertification in Southwest China and for the management of rocky desertification.
{"title":"Spatial distribution and driving factors of karst rocky desertification in Southwest China based on GIS and geodetector","authors":"Dengfeng Wei, Yue Chang, Danni Song, Honghai Kuang","doi":"10.1515/geo-2022-0625","DOIUrl":"https://doi.org/10.1515/geo-2022-0625","url":null,"abstract":"Rocky desertification is a pressing environmental concern in Southwest China, and it significantly impacts local living conditions and regional sustainability. Employing remote sensing on a macro scale, this study focuses on identifying and analyzing the spatial distribution and driving factors of rocky desertification. Conducted in Southwest China, using Landsat data from Google Earth Engine, the research quantitatively extracts information on rocky desertification patches through spectral analysis methods. We investigated the spatial distribution characteristics and driving factors of rocky desertification through geographic information system spatial analysis and a geodetector model. The main conclusions are as follows. The area of rocky desertification in Southwest China covers 217530.4 km² (accounting for 15.6% of Southwest China), with areas of slight, moderate, and severe rocky desertification at 81.3, 7.1, and 11.6%, respectively. Spatially, rocky desertification is primarily distributed in areas where lithology is carbonate rock between clastic rocks and continuous limestone, slope exceeds 15°, elevation range is 1,000–2,000 m, land use types are grassland and woodland, precipitation is 80–120 mm, and population density is below 50 people/km². Human activities have a minimal influence in comparison to natural factors. Geodetector analysis identifies lithology, land use types, and slope as primary driving factors, with interactive effects of lithology and land use type and slope and land use type jointly influencing rocky desertification formation in Southwest China. The results of the study provide a scientific basis for an in-depth understanding of rocky desertification in Southwest China and for the management of rocky desertification.","PeriodicalId":48712,"journal":{"name":"Open Geosciences","volume":"16 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141529202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rakesh K. Aggarwal, Ranjan Das, Hemendra S. Gusain
Knowledge of the Coulomb dynamic coefficient of friction of snow is a vital input parameter for the estimation of run-out distance, velocity, forces, and lateral spread of the snow avalanches in the hilly regions. This parameter is defined as the ratio of the wall shear force to the normal force components of an avalanche. Avalanches are one of the most devastating natural hazards. So, the proper understanding of avalanche flow parameters is vital for the people and the infrastructure in the mountainous regions of the world. Notwithstanding the utmost significance of the Coulomb friction parameter, a few measurements are available for this parameter. In the present work, based on 32 measurements carried out from 2017 to 2020, a new database for the shear force and normal force components of the avalanches and derived values of the dynamic coefficient of friction between the chute steel surface and the flowing snow are presented. The measurements were carried out using a three-component piezoelectric load cells-based dynamometer which in turn was installed on the 12° slope of a 61-m long snow chute, located in the Pir Panjal Himalayan range of India. Based on all the measurements, the average value of the dynamic coefficient of friction for snow-steel surface is estimated to be 0.113 with a standard deviation of 0.032. The results have been exhibited to be in accordance with the published literature. It is expected that the present database will be highly significant for the validation and improvement of avalanche dynamics models especially for high-density wet snow conditions. Further, shear force and normal force components data may be useful for the designing of snow sheds in mountainous regions.
{"title":"New database for the estimation of dynamic coefficient of friction of snow","authors":"Rakesh K. Aggarwal, Ranjan Das, Hemendra S. Gusain","doi":"10.1515/geo-2022-0639","DOIUrl":"https://doi.org/10.1515/geo-2022-0639","url":null,"abstract":"Knowledge of the Coulomb dynamic coefficient of friction of snow is a vital input parameter for the estimation of run-out distance, velocity, forces, and lateral spread of the snow avalanches in the hilly regions. This parameter is defined as the ratio of the wall shear force to the normal force components of an avalanche. Avalanches are one of the most devastating natural hazards. So, the proper understanding of avalanche flow parameters is vital for the people and the infrastructure in the mountainous regions of the world. Notwithstanding the utmost significance of the Coulomb friction parameter, a few measurements are available for this parameter. In the present work, based on 32 measurements carried out from 2017 to 2020, a new database for the shear force and normal force components of the avalanches and derived values of the dynamic coefficient of friction between the chute steel surface and the flowing snow are presented. The measurements were carried out using a three-component piezoelectric load cells-based dynamometer which in turn was installed on the 12° slope of a 61-m long snow chute, located in the Pir Panjal Himalayan range of India. Based on all the measurements, the average value of the dynamic coefficient of friction for snow-steel surface is estimated to be 0.113 with a standard deviation of 0.032. The results have been exhibited to be in accordance with the published literature. It is expected that the present database will be highly significant for the validation and improvement of avalanche dynamics models especially for high-density wet snow conditions. Further, shear force and normal force components data may be useful for the designing of snow sheds in mountainous regions.","PeriodicalId":48712,"journal":{"name":"Open Geosciences","volume":"42 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141190122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Naqadeh Region (NR) is one of the most sensitive regions regarding geo-hazards occurrence in Northwest of Iran. The landslides triggering parameters that identified for the studied region are classified as elevation, aspect, slope angle, lithology, drainage density, distance to river, weathering, land-cover, precipitation, vegetation, distance to faults, distance to roads, and distance to the cities. These triggering factors are selected based on conducting field survey, remote-sensing investigation, and historical development background assessment. Regarding the investigations, 12 large-scale, 15 medium-scale, and 30 small-scale historical landslides (57 in total) were recorded in the NR. The historical landslides were used to provide sensitive area with high probability of ground movements. The objectives of this study are multifaceted, aiming to address critical gaps in understanding and predicting landslide susceptibility in the NR. First, the study seeks to evaluate and compare the effectiveness of support-vector machine (SVM), multilayer perceptron (MLP), and decision tree (DT) algorithms in predicting landslide susceptibility. So, as methodology, the presented study used comparative models for landslide susceptibility based on SVM, MLP, and DT approaches. The predictive models were compared based on model accuracy as the area under the curve of the receiver operating characteristic curve. According to the estimated results, MLP is the highest rank of overall accuracy to provide susceptibility maps for landslides in NR. From a perspective of the risk ability, the west and south-west sides of the county were identified within the hazard area.
{"title":"Comparative models of support-vector machine, multilayer perceptron, and decision tree predication approaches for landslide susceptibility analysis","authors":"Fei Teng, Yimin Mao, Yican Li, Subin Qian, Yaser A. Nanehkaran","doi":"10.1515/geo-2022-0642","DOIUrl":"https://doi.org/10.1515/geo-2022-0642","url":null,"abstract":"Naqadeh Region (NR) is one of the most sensitive regions regarding geo-hazards occurrence in Northwest of Iran. The landslides triggering parameters that identified for the studied region are classified as elevation, aspect, slope angle, lithology, drainage density, distance to river, weathering, land-cover, precipitation, vegetation, distance to faults, distance to roads, and distance to the cities. These triggering factors are selected based on conducting field survey, remote-sensing investigation, and historical development background assessment. Regarding the investigations, 12 large-scale, 15 medium-scale, and 30 small-scale historical landslides (57 in total) were recorded in the NR. The historical landslides were used to provide sensitive area with high probability of ground movements. The objectives of this study are multifaceted, aiming to address critical gaps in understanding and predicting landslide susceptibility in the NR. First, the study seeks to evaluate and compare the effectiveness of support-vector machine (SVM), multilayer perceptron (MLP), and decision tree (DT) algorithms in predicting landslide susceptibility. So, as methodology, the presented study used comparative models for landslide susceptibility based on SVM, MLP, and DT approaches. The predictive models were compared based on model accuracy as the area under the curve of the receiver operating characteristic curve. According to the estimated results, MLP is the highest rank of overall accuracy to provide susceptibility maps for landslides in NR. From a perspective of the risk ability, the west and south-west sides of the county were identified within the hazard area.","PeriodicalId":48712,"journal":{"name":"Open Geosciences","volume":"39 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141190164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shear strengths of silty soil were determined for shallow destruction of the soil sites frequently occurring in the Central Plains area. Specimens were prepared with five different clay contents (5, 10, 15, 20, and 25%) prior to compaction at dry densities of 1.60, 1.70, and 1.80 g/cm3. Soil specimens were saturated and then the consolidated undrained shear test was conducted with eight confined pressures ranging from 1 to 400 kPa. Results indicate that the shear strength increases significantly as the clay content increases from 5 to 25%, and the cohesion c shows bilinear function with the inflection point at the clay content of 10%. The difference of cohesion in the high and low stress sections decreases gradually to almost the same value until 25% of the clay content, while the internal friction angle φ decreases with the increase in clay content. Within the range of dry density and clay content tested, the shear strength of silty soil in the low stress range obtained is higher than the measured value. Therefore, for the shallow damage of soil site, the shear strength parameters should consider the low stress test conditions. The bilinear growth of cohesion c with clay content can be attributed to the changes from “sand-like soil” to “clay-like soil” with the skeleton of soil specimen transitioning from sand particles to “clay grid” when the clay content exceeds approximately 10% combined with the results of scanning electron microscopy.
{"title":"Experimental study on the influence of clay content on the shear strength of silty soil and mechanism analysis","authors":"Haibiao Xu, Xinming Li, Pengpeng Liu, Song Yin, Kebin Ren, Yuzhou Sun, Jinming Geng","doi":"10.1515/geo-2022-0647","DOIUrl":"https://doi.org/10.1515/geo-2022-0647","url":null,"abstract":"Shear strengths of silty soil were determined for shallow destruction of the soil sites frequently occurring in the Central Plains area. Specimens were prepared with five different clay contents (5, 10, 15, 20, and 25%) prior to compaction at dry densities of 1.60, 1.70, and 1.80 g/cm<jats:sup>3</jats:sup>. Soil specimens were saturated and then the consolidated undrained shear test was conducted with eight confined pressures ranging from 1 to 400 kPa. Results indicate that the shear strength increases significantly as the clay content increases from 5 to 25%, and the cohesion <jats:italic>c</jats:italic> shows bilinear function with the inflection point at the clay content of 10%. The difference of cohesion in the high and low stress sections decreases gradually to almost the same value until 25% of the clay content, while the internal friction angle <jats:italic>φ</jats:italic> decreases with the increase in clay content. Within the range of dry density and clay content tested, the shear strength of silty soil in the low stress range obtained is higher than the measured value. Therefore, for the shallow damage of soil site, the shear strength parameters should consider the low stress test conditions. The bilinear growth of cohesion <jats:italic>c</jats:italic> with clay content can be attributed to the changes from “sand-like soil” to “clay-like soil” with the skeleton of soil specimen transitioning from sand particles to “clay grid” when the clay content exceeds approximately 10% combined with the results of scanning electron microscopy.","PeriodicalId":48712,"journal":{"name":"Open Geosciences","volume":"42 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141190165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The proliferation of urban sprawl has emerged as a prevalent occurrence in response to the rapid expansion of the worldwide population. The objective of this study is to determine the level of freedom for urban expansion using Pearson’s Chi-square (χ2) index and the amount of urban spatial dispersion using the Shannon entropy (Hn{H}_{n}) index in Hue City, Vietnam. While the first index asserts the degree of freedom for observed urban growth above expected urban growth, the second index is applied to analyze urban spatial dispersion patterns through richness and evenness. Land use map data were collected from Japan’s JAXA agency from 1990–2020. Research results show that, in the past 10 years (2010–2020), the level of urban freedom expansion in Hue city has increased compared to the period 2000–2010 and 1990–2000, with corresponding χ2 values of 219.18, 150.05, and 106.95. The South-Southwest (TNN) area is also the area with the most significant urban freedom expansion among the eight regions in Hue City through three stages. The urban dispersion level in Hue City has also expanded recently when the Hn{H}_{n} and Hn′{H}_{n}^{^{prime} } indexes gradually increased from 1990 to 2020. This result puts pressure on the Hue city government on how to develop the city sustainably. Therefore, the study also points out some disarmament to contribute to sustainable urban development.
随着全球人口的迅速增长，城市无计划扩展的现象也日益普遍。本研究的目的是利用皮尔逊方差（χ2）指数确定城市扩张的自由度，并利用香农熵（H n {H}_{n} ）指数确定越南顺化市的城市空间分散程度。第一个指数确定观察到的城市增长高于预期城市增长的自由度，第二个指数则通过丰富度和均匀度分析城市空间离散模式。1990-2020 年期间的土地利用地图数据来自日本 JAXA 机构。研究结果表明，与 2000-2010 年和 1990-2000 年相比，顺化市近 10 年（2010-2020 年）的城市自由扩展水平有所提高，相应的 χ2 值分别为 219.18、150.05 和 106.95。在顺化市的八个区域中，南南西（TNN）区域也是城市自由度扩张最明显的区域，共经历了三个阶段。从 1990 年到 2020 年，顺化市的 H n {H}_{n} 和 H n ′ {H}_{n}^{^{prime} } 指数逐渐上升，顺化市的城市离散程度也在近期有所扩大。这一结果给顺化市政府带来了如何可持续发展城市的压力。因此，研究还指出了一些有助于城市可持续发展的裁军措施。
{"title":"Measuring urban growth dynamics: A study in Hue city, Vietnam","authors":"Nguyen Tran Tuan","doi":"10.1515/geo-2022-0640","DOIUrl":"https://doi.org/10.1515/geo-2022-0640","url":null,"abstract":"The proliferation of urban sprawl has emerged as a prevalent occurrence in response to the rapid expansion of the worldwide population. The objective of this study is to determine the level of freedom for urban expansion using Pearson’s Chi-square (χ<jats:sup>2</jats:sup>) index and the amount of urban spatial dispersion using the Shannon entropy (<jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/j_geo-2022-0640_eq_001.png\"/> <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\"> <m:msub> <m:mrow> <m:mi>H</m:mi> </m:mrow> <m:mrow> <m:mi>n</m:mi> </m:mrow> </m:msub> </m:math> <jats:tex-math>{H}_{n}</jats:tex-math> </jats:alternatives> </jats:inline-formula>) index in Hue City, Vietnam. While the first index asserts the degree of freedom for observed urban growth above expected urban growth, the second index is applied to analyze urban spatial dispersion patterns through richness and evenness. Land use map data were collected from Japan’s JAXA agency from 1990–2020. Research results show that, in the past 10 years (2010–2020), the level of urban freedom expansion in Hue city has increased compared to the period 2000–2010 and 1990–2000, with corresponding χ<jats:sup>2</jats:sup> values of 219.18, 150.05, and 106.95. The South-Southwest (TNN) area is also the area with the most significant urban freedom expansion among the eight regions in Hue City through three stages. The urban dispersion level in Hue City has also expanded recently when the <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/j_geo-2022-0640_eq_002.png\"/> <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\"> <m:msub> <m:mrow> <m:mi>H</m:mi> </m:mrow> <m:mrow> <m:mi>n</m:mi> </m:mrow> </m:msub> </m:math> <jats:tex-math>{H}_{n}</jats:tex-math> </jats:alternatives> </jats:inline-formula> and <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/j_geo-2022-0640_eq_003.png\"/> <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\"> <m:msubsup> <m:mrow> <m:mi>H</m:mi> </m:mrow> <m:mrow> <m:mi>n</m:mi> </m:mrow> <m:mrow> <m:mo accent=\"true\">′</m:mo> </m:mrow> </m:msubsup> </m:math> <jats:tex-math>{H}_{n}^{^{prime} }</jats:tex-math> </jats:alternatives> </jats:inline-formula> indexes gradually increased from 1990 to 2020. This result puts pressure on the Hue city government on how to develop the city sustainably. Therefore, the study also points out some disarmament to contribute to sustainable urban development.","PeriodicalId":48712,"journal":{"name":"Open Geosciences","volume":"101-102 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141190166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present study aims to identify whether the delineation of potential groundwater potential zones (GWPZs) is essential for monitoring surface and conserving underground water resources. This study analysed the morphology of earth surface characteristics such as geomorphology, lineament density, lithology, slope, soil types, land use and land cover, drainage density, land surface temperature, normalized difference vegetation index, rainfall, and topographic wetness index parameters to delineate the potential groundwater zones. This article applies the analytical hierarchy process (AHP) and multi-influence factor (MIF) methods to identify potential groundwater zones in the Tirunelveli and Tenkasi districts of Tamil Nadu, India. In the AHP method, individual parameter's geometric mean and normalized weights were determined using the pair-wise matrix analytical method. Remote sensing-geographic information system (RS-GIS) techniques were used to generate thematic map layers from normalized weights to delineate GWPZs. The GWPZs were classified as Very Low, Low, Medium, High, and Very High. The result shows that the GWPZs were identified as 3.57, 0.55, 6.62, 58.09, and 31.21% in the study area for the five classes, respectively. In this study, the thematic maps were also prepared by assigning fixed scores and weights from the MIF approach. In the MIF approach, GWPZs were classified into five classes and identified as 3.16, 0.33, 2.14, 61.21, and 33.16% in the study area, respectively. GWPZ maps were evaluated for both MIF and AHP techniques using the Kappa statistics method with agreement values of 0.77 and 0.72%, respectively. This study's GIS-RS method is more proficient and efficient in delineating the GWPZs.
{"title":"MIF and AHP methods for delineation of groundwater potential zones using remote sensing and GIS techniques in Tirunelveli, Tenkasi District, India","authors":"Samuel Prabaharan Jebaraj, Viji Rajagopal","doi":"10.1515/geo-2022-0619","DOIUrl":"https://doi.org/10.1515/geo-2022-0619","url":null,"abstract":"The present study aims to identify whether the delineation of potential groundwater potential zones (GWPZs) is essential for monitoring surface and conserving underground water resources. This study analysed the morphology of earth surface characteristics such as geomorphology, lineament density, lithology, slope, soil types, land use and land cover, drainage density, land surface temperature, normalized difference vegetation index, rainfall, and topographic wetness index parameters to delineate the potential groundwater zones. This article applies the analytical hierarchy process (AHP) and multi-influence factor (MIF) methods to identify potential groundwater zones in the Tirunelveli and Tenkasi districts of Tamil Nadu, India. In the AHP method, individual parameter's geometric mean and normalized weights were determined using the pair-wise matrix analytical method. Remote sensing-geographic information system (RS-GIS) techniques were used to generate thematic map layers from normalized weights to delineate GWPZs. The GWPZs were classified as Very Low, Low, Medium, High, and Very High. The result shows that the GWPZs were identified as 3.57, 0.55, 6.62, 58.09, and 31.21% in the study area for the five classes, respectively. In this study, the thematic maps were also prepared by assigning fixed scores and weights from the MIF approach. In the MIF approach, GWPZs were classified into five classes and identified as 3.16, 0.33, 2.14, 61.21, and 33.16% in the study area, respectively. GWPZ maps were evaluated for both MIF and AHP techniques using the Kappa statistics method with agreement values of 0.77 and 0.72%, respectively. This study's GIS-RS method is more proficient and efficient in delineating the GWPZs.","PeriodicalId":48712,"journal":{"name":"Open Geosciences","volume":"7 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141150399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shengming Chen, Meiling Ji, Zeyou Chen, Yong Xiang
The conflict between the supply and consumption of water resources (WR) is a growing concern, and water scarcity has become a major obstacle to the sustainable development of Chinese cities. To address this issue, the resilience assessment regulation model has proven to be an effective tool for decision makers. This model helps them determine how to improve the resilience of WR building systems and mitigate potential risks and threats. The aim of this article is to explore the evaluation and regulation of the resilience of WR building systems, with the goal of alleviating the WR crisis and promoting sustainable development. Through the construction of an evaluation index system, determination of index weights, design of evaluation models, and application of case studies, the fuzzy comprehensive evaluation method was employed to assess the resilience of WR systems. Additionally, an evaluation regulation model was established, along with the proposed regulation method. The evaluation index system consists of four dimensions: flexibility, adaptability, resilience, and fault tolerance.
{"title":"Evaluation and control model for resilience of water resource building system based on fuzzy comprehensive evaluation method and its application","authors":"Shengming Chen, Meiling Ji, Zeyou Chen, Yong Xiang","doi":"10.1515/geo-2022-0576","DOIUrl":"https://doi.org/10.1515/geo-2022-0576","url":null,"abstract":"The conflict between the supply and consumption of water resources (WR) is a growing concern, and water scarcity has become a major obstacle to the sustainable development of Chinese cities. To address this issue, the resilience assessment regulation model has proven to be an effective tool for decision makers. This model helps them determine how to improve the resilience of WR building systems and mitigate potential risks and threats. The aim of this article is to explore the evaluation and regulation of the resilience of WR building systems, with the goal of alleviating the WR crisis and promoting sustainable development. Through the construction of an evaluation index system, determination of index weights, design of evaluation models, and application of case studies, the fuzzy comprehensive evaluation method was employed to assess the resilience of WR systems. Additionally, an evaluation regulation model was established, along with the proposed regulation method. The evaluation index system consists of four dimensions: flexibility, adaptability, resilience, and fault tolerance.","PeriodicalId":48712,"journal":{"name":"Open Geosciences","volume":"7 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141150555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ling Zhang, Jinsongdi Yu, Ruiju Tong, Dandan Wei, Yu Fan
With the continuous development of Earth Observation technology, resolution of imagery and gridded data has significantly increased, leading to a rapid increase in data volume. To efficiently acquire and analyze these vast amounts of imagery and gridded data, image tiling technology has been developed to effectively access data of interested areas. Tiling technology divides large-scale image data into smaller tiles, providing fast, accurate, and efficient access support for imagery and gridded data. The spatial grid model, as the foundational framework of the new generation of geographic spatial information, plays a critical role in the retrieval, integration, services, and applications of imagery and gridded data resources. When tiling image data based on the spatial grid model, it always generates both complete and incomplete tiles. Particularly, when conducting image tile retrieval using the same rule-based grid in the retrieval area, incomplete tile phenomena along the boundary regions of the retrieved images often occur, resulting in gaps within the retrieval area. To tackle this issue, in this study, we present a new topological model called the Grid Six-Intersection Model (G-6IM), specifically designed for regular rectangular grids, to accurately represent boundary issues in image tiling. Through a practical case study, we demonstrate the effectiveness and practical application potential of the proposed G-6IM model, providing new insights and guidance for the improvement and optimization of imagery and gridded data tiling technology.
{"title":"Addressing incomplete tile phenomena in image tiling: Introducing the grid six-intersection model","authors":"Ling Zhang, Jinsongdi Yu, Ruiju Tong, Dandan Wei, Yu Fan","doi":"10.1515/geo-2022-0628","DOIUrl":"https://doi.org/10.1515/geo-2022-0628","url":null,"abstract":"With the continuous development of Earth Observation technology, resolution of imagery and gridded data has significantly increased, leading to a rapid increase in data volume. To efficiently acquire and analyze these vast amounts of imagery and gridded data, image tiling technology has been developed to effectively access data of interested areas. Tiling technology divides large-scale image data into smaller tiles, providing fast, accurate, and efficient access support for imagery and gridded data. The spatial grid model, as the foundational framework of the new generation of geographic spatial information, plays a critical role in the retrieval, integration, services, and applications of imagery and gridded data resources. When tiling image data based on the spatial grid model, it always generates both complete and incomplete tiles. Particularly, when conducting image tile retrieval using the same rule-based grid in the retrieval area, incomplete tile phenomena along the boundary regions of the retrieved images often occur, resulting in gaps within the retrieval area. To tackle this issue, in this study, we present a new topological model called the Grid Six-Intersection Model (G-6IM), specifically designed for regular rectangular grids, to accurately represent boundary issues in image tiling. Through a practical case study, we demonstrate the effectiveness and practical application potential of the proposed G-6IM model, providing new insights and guidance for the improvement and optimization of imagery and gridded data tiling technology.","PeriodicalId":48712,"journal":{"name":"Open Geosciences","volume":"134 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141063907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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