Bivariate statistical index for landslide susceptibility mapping in the Rorachu river basin of eastern Sikkim Himalaya, India

Sujit Mandal,Kanu Mandal 대한공간정보학회 2018 Spatial Information Research Vol.26 No.1

The main goal of the study is to prepare a landslide susceptibility map under Geographical Information System (GIS) environment using statistical index model to identify and demarcate the areas of future landslide occurrence. Firstly, landslide locations were identified with the help of previous reports, satellite images and intensive field study. For the preparation of landslide inventory, 80 landslide locations were identified and randomly separated to create training and validation datasets. Fifty landslides (62.5%) were used as training dataset and remaining 30 landslides (37.5%) were used for validating the model. Twelve landslide conditioning factors, including morphometric factors (slope angle, slope aspect, curvature, relative relief and drainage density) and non-morphometric factors (bedrock geology, soil, distance from drainage, distance from lineament, distance from road, Normalized Difference Vegetation Index (NDVI) and land use/land cover), were used to generate landslide susceptibility map of Rorachu river basin. Finally, the accuracy of the model was assessed by area under curve of Receiver Operating Characteristics (ROC) curve and landslide density method. The statistics of ROC curve showed that, the landslide susceptibility map using statistical index model has an accuracy of 91% which indicates a very good predictive capacity of the model. The result reveals that, landslide density of the Rorachu river basin is increasing with landslide susceptibility classes.

Landslide susceptibility mapping using modified information value model in the Lish river basin of Darjiling Himalaya

Biplab Mandal,Sujit Mandal 대한공간정보학회 2017 Spatial Information Research Vol.25 No.2

The spatial distribution of mountain slope instability deals with the potential zones for landslides occurrences. In the present study, information value model was modified to make the modified information value model using RS & GIS to assess landslide susceptibility of the Lish river basin of Eastern Darjeeling Himalaya. Eleven important causative factors of slope instability like slope, aspect, curvature, lithology, geomorphology, soil, NDVI, drainage density, relative relief, LULC, elevation were considered and corresponding thematic data layers were generated in Arc GIS (10.1) environments. 87 very small to large various types landslide locations were identified with the help GPS through extensive field survey and incorporating Google earth image (2015). The entire thematic data layers were extracted from ASTER GDEM, Topographical maps (78 B/9; 1: 50,000), LANDSAT 8 OLI satellite image, Google earth image (2015) etc. All the thematic data layers were integrated on GIS environment to generate the landslide susceptibility map of the study area. The Lish river basin was classified into six landslide susceptibility zones i.e. very low, low, moderate, moderately high, high and very high considering the ranges of landslide susceptibility index. Finally, an accuracy assessment was done in Arc GIS by ground truth verification of 54 training sites having landslides from Google earth image (2015) for each landslide susceptibility class and compared with probability model which demonstrates the overall accuracy of the present study is 87.04% and Kappa coefficient is 84.41%.

Wind induced response of corner modified ‘U’ plan shaped tall building

Shanku Mandal,Sujit K. Dalui,Soumya Bhattacharjya 한국풍공학회 2021 Wind and Structures, An International Journal (WAS Vol.32 No.6

In the present study, the well-adopted practice of minor aerodynamic modifications (chamfered corner and rounded corner) has been introduced on widely used irregular U plan shaped tall building to minimize the wind induced responses and also to give a good aesthetics. The necessary design inputs for a wind resistance design such as force coefficient and pressure coefficients have been well explored and illustrated graphically to provide a complete guideline to the designer. The randomness of wind directionality has a significant impact on tall structures, which is generally not detailed in existing design codes, is incorporated by considering wind directions ranging from 0° to 180° at an interval of 15°. Computational fluid dynamics (CFD) has been utilized to simulate wind flow using two turbulence models, i.e., k-epsilon and Shear Stress Transport. The model has been validated by comparing the results of a published research article on a U-shaped building without corner modification. The grid independence study has been done to check the reliability and accuracy of the analysis results. Since such study of wind directionality on corner modified U-shaped building is not observed in the existing literature, it constitutes the uniqueness of the present study. A significant reduction in force coefficient has been achieved by implementing modification, but the faces of those updated corners mostly been attracted by excessive pressure. This indicates the necessity of proper cladding configurations. The rounded corner buildings are turning out to be more effective when compared to the chamfered corner for reducing wind load.

Room Temperature Synthesis of Perovskite Hydroxide, MnSn(OH)6: A Negative Electrode for Supercapacitor

Manas Mandal,Krishna Chattopadhyay,Malay Chakraborty,Wonjae Shin,Kamal Kanti Bera,Sujit Chatterjee,Akbar Hossain,Dipanwita Majumdar,Arup Gayen,Changwoon Nah,Swapan Kumar Bhattacharya 대한금속·재료학회 2022 ELECTRONIC MATERIALS LETTERS Vol.18 No.6

A negative electrode is constructed based on MnSn(OH)6 nanocubes prepared by a simple precipitation method at roomtemperature for supercapacitor application. The as-prepared material was structurally and morphologically characterizedwith the help of XRD, FT-IR, Raman, XPS, FESEM, and HRTEM analyses. The uniform structure and fine edge morphologywith high conductivity due to oxygen vacancies promote the redox reaction, which results in high pseudocapacitance. Theelectrochemical performance is investigated through a three-electrode cell system in a negative potential window (− 1.0 to0.0 V). A maximum specific capacitance of 209 F/g is calculated at a specific current of 1 A/g. The electrodes also exhibitexcellent cycling stability (79% specific capacitance retention after 3000 consecutive GCD cycles).

Assessing channel migration dynamics and vulnerability (1977–2018) of the Torsa River in the Duars and Tal region of eastern Himalayan foothills, West Bengal, India

Sourav Dey,Sujit Mandal 대한공간정보학회 2019 Spatial Information Research Vol.27 No.1

Channel migration is perhaps the most rampant quasi-natural hazard that is commonly experienced in the eastern Himalayan foothills of Duars and Tal region, India. The present study is dealt with the Torsa River, which is situated in the Duars and Tal region. The study aims at the changing rate of channel migration and vulnerability of the Torsa River in Duars and Tal region on spatial and temporal basis using geospatial methods. The changing course of the Torsa River was detected using remote sensing and GIS since 1977–2018 (42 years). USGS Landsat MSS, ETM, OLI_TRIS sensor data (1977, 2010 and 2018) were considered to demarcate the chronological changes of the river course. Normalized Difference Water Index was used to extract the surface water bodies. Sixteen cross sections have been considered to delimit the river course migration pattern. The results showed that the Torsa River course has been migrating towards the right bank at different places of the study area. In the downstream of Patla Khawa Protected Forest, the continuous lateral migration of the river Torsa and associated river bank erosion invited the loss of agricultural land and socio-economic vulnerability in most of the villages of Cooch Behar I, Cooch Behar II and Mathabhanga II blocks of Cooch Behar district, West Bengal. Therefore, the present study may be helpful for ensuing suitable site specific management options which may check future river bank erosion as well as loss of livelihood and properties.

Identification of suitable human habitation sites through the river bank stability analysis on Ganga–Pagla interfluves area of West Bengal, India

Samrat Majumdar,Sujit Mandal 대한공간정보학회 2020 Spatial Information Research Vol.28 No.2

One of the important geo-hazards associated with a river is bank erosion. In recent years the district of Malda has been facing ravages of this hazard by the continuous left bank erosion by the river Ganga. Although the entire district has witnessed rapid bank erosion, the village of Panchanandapur has become famous in terms of this hazard as it has been at the receiving end for a major proportion. This paper focuses on the topography and land use of this area so as to understand the probable causal mechanism and vulnerability of Panchanandapur. Bank Erosion Hazardous Index and Near Bank Stress have also been done for stability measurements of both banks. Besides analysing the spatial variation in the aforesaid parameters, we have also postulated the favourable sites for the growth of settlements based on information obtained from the analysis. DEM based study and field-based land use morphology indicates that the current location of Panchanandapur Village is highly vulnerable to bank erosion as well as water logging since it is located between the natural levees formed by the Ganga River and one of its major distributaries, the Pagla. Needless to state that the village is at a significant lower elevation than the levees of Ganga and Pagla. Furthermore, this study has pointed out that the current levee of the Pagla is currently ideally suited for settlement growth as it appears to be reasonably inert to bank erosion and water logging.

Application of frequency ratio (FR) model in spatial prediction of landslides in the Balason river basin, Darjeeling Himalaya

Subrata Mondal,Sujit Mandal 대한공간정보학회 2017 Spatial Information Research Vol.25 No.3

The present study aims to prepare landslide susceptibility map using frequency ratio (FR) model in the Balason river basin of Darjeeling Himalaya. Along with keeping in mind that, can the produced landslide susceptibility map yields acceptable landslide prediction accuracy or not. For that reliable landslide inventory map was prepared with a total of 295 landslide locations. The chosen landslide conditioning factors were altitude, aspect, slope angle, curvature, geology, geomorphology, soil, land use/land cover, normalized differential vegetation index, drainage density, lineament density, distance from lineament, distance to drainage, stream power index and topographic wetted index. To estimate FR value for each class of all the landslide conditioning factors pixels affected by landslide (%) and total pixels (%) were taken into account. FR model was applied to integrate all the data layers on GIS platform. The derived susceptibility map was divided into five categories i.e. very low, low moderate, high and very high which cover 17.52, 18.71, 30.35, 24.49 and 8.92% area of the basin respectively. The area under curve value of receiver operating characteristics indicates the prediction accuracy of the prepared map was 94.2% that is highly desirable. FR plots represent that there were positive relationship between landslide susceptibility classes and FR value. The prepared map will helping developers and planners to implement slope management plans, land use plans and other development action plans in this area.

Acceptance of BANCS model for predicting stream bank erosion potential and rate in the left bank of Ganga river of Diara region in Malda district, North East India

Samrat Majumdar,Mandal Sujit 대한공간정보학회 2021 Spatial Information Research Vol.29 No.1

River bank erosion is a hazardous problem of Malda district. Different parts of Malda are mainly eroded by hydraulic action of River Ganga. Bank assessment for non-point source consequences of sediment model is a well accepted process for predicting stream bank erosion hazard potential. In the present study, river bank stability condition has been measured form field survey on 15 sample segments for 185 km stretched from Rajmahal in Sahibganj district, Jharkhand to upstream of Farakka barrage in Malda. In the present study, bank erosion hazard index (BEHI), near bank stress (NBS) and field based data have been considered for assessing stream bank erosion. The result shows that BEHI is high along the whole given left bank line extension of river Ganga, among these BEHI is very high in the upper segments of the river and adjacent river bank line extension of Farakka barrage, overall NBS conditions along left river bank line are less compare to the BEHI. Dominant NBS conditions are belong under moderate to low along the river bank line. Loosely compact alluvial soil, sparse vegetation, steep slope, unorganized agricultural activities; sinuous channel can be responsible for river bank erosion hazard potentiality. On an average 976,068.991 metric tons of sediments entrains to the river in a year. Bank has experienced variants bank erosion from same BEHI and NBS combinations. So, it can be concluded that BEHI and NBS are potentially not significant model for predicting bank erosion in present study.

Monitoring changing course of the river Ganga and land-use dynamicity in Manikchak Diara of Malda district, West Bengal, India, using geospatial tools

Jayanta Mondal,Sujit Mandal 대한공간정보학회 2018 Spatial Information Research Vol.26 No.6

Dynamicity of the river Ganga introduces significant changes in the land-use character of active alluvial plain of West Bengal, India. The dynamicity of the river Ganga is caused due to continuous sedimentation and formation of char land which frequently changes the flow direction and flow velocity of running water as well as causes the shifting of the bank line due to active bank erosion processes in the upstream of Farakka Barrage. Bank line shifting was estimated with the help of 25 transects since 1973–2011. A large-scale land erosion (38.6 sq. km area) occurred due to the bank line shifting which observed in Godai, Kesharpur, Rambari, Hiranandapur, Mathurapur, Manikchak, Samastipur, Dakshin Chandipur, and Gopalpur mouzas of Manikchak block, whereas deposition (2.4 sq. km area) was found in Chandipur Tofi Narayanpur and Govindapur mouzas. Such erosion and deposition invited a lot of changes in land-use statistics. Land-use–land-cover maps were prepared using supervised image classification techniques and validated through kappa statistics (kappa coefficient 0.803 and 0.892 for the year 1994 and 2016, respectively). Land-use change detection technique was used to identify the transformation of land-use character from one feature to another. This study revealed that a notable area of settlement (5.07 sq. km) and vegetation cover (6.84 sq. km) was converted into water body as a result of bank erosion. Loss of agricultural land and homestead led to the loss of livelihood and introduced internal migration. The observed pattern of river dynamics and the consequent land-use change in the recent decades have shown newer environmental challenges to the coping capabilities of the rural inhabitants.

Non-exhaust particulate pollution in Asian countries: A comprehensive review of sources, composition, and health effects

Anamika Roy,Mamun Mandal,Sujit Das,Manoj Kumar,Robert Popek,Amit Awasthi,Balendu Shekher Giri,Kartick Chandra Mondal,Abhijit Sarkar 대한환경공학회 2023 Environmental Engineering Research Vol.29 No.3

Recent regulations on exhaust emissions have led to an increase in non-exhaust emissions, which now surpasses exhaust emissions. Non-exhaust emissions are mainly generated from brake and tire particle abrasion, road wear, and re-suspended road dust. In Asia, non-exhaust emissions have increased significantly over the past 50 years, resulting in almost 92% of the population breathing polluted air, which accounts for 70% of air pollution related-deaths. Most Asian countries with poor air quality are developing or underdeveloped. Taking this into consideration, the current study aims to shed light on particulate pollution from non-exhaust emissions in the Asian context to assess the current status and its health consequences and provides technological solutions. The study is based on an in-depth analysis of existing reviews and research concerning non-exhaust emissions and their health impacts in Asia to pinpoint knowledge gaps. The study found that particulate pollutants had exceeded WHOs standards in many Asian countries, bringing deleterious health consequences among children and the elderly. The findings underscore the significance of future researchers efforts to devise solutions that curtail non-exhaust emissions, ultimately reducing air pollution, augmenting air quality, fostering better health outcomes, and paving way for a more sustainable future before it is too late.