VNU Journal of Science: Earth and Environmental Sciences最新文献

{"title":"Biodiversity Assessment of Some Aquatic Communities Indicates the Environmental Quality of the Ecosystemsin Mekong Estuary","authors":"N. Q. Huy, Nguyen Thi Hong Hanh, T. Thủy, Le Ngoc Mai, Do Quy Manh, Doan Thi Nhat Minh","doi":"10.25073/2588-1094/VNUEES.4515","DOIUrl":"https://doi.org/10.25073/2588-1094/VNUEES.4515","url":null,"abstract":"The Mekong River mouths have a significance of biodiversity and biological resources, especially for the floating and benthic communities in the ecosystem. The study area belongs to 4 provinces in the lower Mekong River: Tien Giang, Tra Vinh, Ben Tre, and Soc Trang. The results of Shannon-Wiener biodiversity value assessment and Berger Parke index of 3 major aquatic communities in the area including phytoplankton, zooplankton and benthic showed that biodiversity was at low levels in terms of species composition as well as biodiversity values. More noteworthy is that the benthic animal communities were at the highest level of risk of loss and biodiversity value loss, mainly due to socio-economic activities, dam construction activities, the industrial and agricultural activities that have made the environment here, especially the sediment environment, strongly affected. The study has proposed a number of solutions to minimize the rapid decline of biodiversity of the region by specific measures from many directions: management, education, propaganda, conservation, and prevention of the factors affecting the quality of ecosystem in the region.","PeriodicalId":247618,"journal":{"name":"VNU Journal of Science: Earth and Environmental Sciences","volume":"255 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114447892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Urban Classification Using Multi-temporal Sentinel-1 Data Based On Coherence Characteristics","authors":"Le Minh Hang, T. Tuan","doi":"10.25073/2588-1094/VNUEES.4637","DOIUrl":"https://doi.org/10.25073/2588-1094/VNUEES.4637","url":null,"abstract":"The paper presents the method of urban classification using the coherence characteristics of pairs of SAR images observed at different times. Two scenes of Sentinel-1A VV and VH polarized on January 16, 2020, and January 28, 2020, in some central districts of Hanoi city were used experimentally in this study. The primary data processing steps included: (1) Creating the coherence image by using a pair of SAR interference images; (2) Processing coherence image by computing multi-look and geometric correction to UTM coordinate system; (3) Classification of the coherence image to urban/non-urban areas threshold method. The results showed that the urban extracted from the VH polarization image was better than the VV polarization image. The overall accuracy of classification achieved for VV and VH polarized images were 89% and 93%. Using SAR image pairs to classify urban areas that were not affected by weather conditions, showed good efficiency in managing and monitoring urban space in Vietnam cities","PeriodicalId":247618,"journal":{"name":"VNU Journal of Science: Earth and Environmental Sciences","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116246345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Moisture Transfer Finite Element Modeling with Soil-Water Characteristic Curve-Based Parameters and its Application to Nhan Co Red Mud Basin Slope","authors":"N. Hoang, H. V. Hung, P. Dung","doi":"10.25073/2588-1094/VNUEES.4655","DOIUrl":"https://doi.org/10.25073/2588-1094/VNUEES.4655","url":null,"abstract":"Since the year of 2017, landslides at the red mud basins in Nhan Co alumina factory, Dak Nong province have been occurring during the rainy season. The change of the soil physical and mechanical parameters due to rainwater infiltration has been considered as the main factor of the slope instability. The soil cohesion and angle of internal friction depend greatly on the soil moisture. Specifically, soil with a lower moisture content has a higher shearing strength than that in soil with higher moisture content. The finite element modeling of moisture transfers in unsaturated soils through the relationship between soil moisture, soil suction, unsaturated permeability and soilmoisture dispersivity is capable of accurately predicting the wetting front development. The element sizes and time steps have been selected based on detailed analysis of analytical error estimation and on the numerical simulations with different element sizes numerical simulation errors. Soil samples had been taken then the soil different suctions and corresponding soil moisture values have been determined in the laboratory. The soil water characteristic curve (SWCC) parameters (a, n and m) have been determined by the best fitting using the least squared error method. The hydraulic conductivity of the saturated soil, one of the key input parameters was also determined. The results of the application to the study area's slope has shown that the wetting front depth could be up to 8 meters for 90 days of moisture transfer due to the rainwater infiltration. The wetting front depth and the length of the intermediate part of the moisture distribution curve have increased with the infiltration time. The soil moisture distribution with a depth is an essential information to have soil strength parameters for the slope stability analyses. The slope stability analysis with the soil shear ________ * Corresponding author. E-mail address: VDC@yahoo.com https://doi.org/10.25073/2588-1094/vnuees.4655 N.V. Hoang et al. / VNU Journal of Science: Earth and Environmental Sciences, Vol. 37, No. 1 (2021) 103-115 104 strength parameters which are strictly corresponding with the moisture change would provide the most accurate and reliable slope stability results and provide more reliable slope stabilization solutions.","PeriodicalId":247618,"journal":{"name":"VNU Journal of Science: Earth and Environmental Sciences","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123119331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simultaneous Determination and Preliminary Source Estimation of Polychlorinated Biphenyls and Polybrominated Diphenyl Ethers in Road Dust from Northern Vietnam","authors":"Hoang Quoc Anh, Shin Takahashi, Pham Thi Mai, Thai Thu Thuy, Nguyen Thi Giang Huong","doi":"10.25073/2588-1094/VNUEES.4541","DOIUrl":"https://doi.org/10.25073/2588-1094/VNUEES.4541","url":null,"abstract":"Concentrations of seven indicator polychlorinated biphenyls (Ʃ7PCBs) and eight predominant polybrominated diphenyl ethers (Ʃ8PBDEs) were examined in outdoor dust samples collected from some representative areas in northern Vietnam, including a core urban area of Hanoi City, an industrial park in Thai Nguyen Province, and a rural area in Bac Giang Province. Levels (median and range) of Ʃ7PCBs and Ʃ8PBDEs in our dust samples were 2.8 (0.028–22) and 11 (0.55– 52) ng/g, respectively. Concentrations of PCBs and PBDEs in the urban and industrial dust samples were significantly higher than those measured in the rural ones, suggesting the role of urbanizationindustrialization processes on the emission of these pollutants. PCBs exhibited specific profiles in the industrial dusts with significant proportions of low-chlorinated congeners such as CB-28 and CB-52, while the remaining samples were more contaminated by heavier compounds such as CB118, CB-138, and CB-153. For PBDEs, BDE-209 was the most predominant congener in all the samples. Emission souces of PCBs and PBDEs in our dust samples were estimated to be household, traffic, and industrial activities. Human exposure to PCBs and PBDEs in outdoor dusts was estimated, implying relatively low health risk.","PeriodicalId":247618,"journal":{"name":"VNU Journal of Science: Earth and Environmental Sciences","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131120646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Capillary Characteristics and Applicability of Coal Bottom Ash as an Anti-Capillary Material for Coastal Constructions","authors":"Hà Nội, N. Trai, V. Nam, P. Hung, Mỹ Đình","doi":"10.25073/2588-1094/vnuees.4517","DOIUrl":"https://doi.org/10.25073/2588-1094/vnuees.4517","url":null,"abstract":"Utilization of Coal bottom ash (CBA) as well as finding the solutions to prevent saline intrusion, meeting the needs of coastal infrastructure development have been considered by the authors of the article for a long time. In this study, the authors focused on analyzing capillary characteristics in order to find a suitable group of CBA particles, which can be applied in the design of foundations with the high ability in restricting or preventing the effects of salt in saline groundwater. The obtained results show that (1) The capillary height is inversely proportional to the particle size: the larger the particle, the smaller the capillary height and vice versa. The CBA group with a diameter of 2.0 - 5.0 mm has an average capillary height around 3.33 cm; a group of particles size of 1.0 - 2.0 mm is 7.16 cm; a group of particles size of 0.5 – 1.0 mm is 23.36 cm. Meanwhile, the group of particles size of 0.1 - 0.5 mm is 31.26 cm. (2) The capillary height is inversely proportional to the salt concentration in the capillary solution: the maximum capillary height exhibits with the lowest capillary solution salinity ~ 0.0 g/L, whereas it reaches minimum value when salinity approximate 33.0 g/L. Thus, CBA with the same particle size of gravel (diameter from 2.0 to 5.0 mm) is able to block capillary flow. This study forms the basis for the design solutions of anti-saline foundation, especially in the context of climate change and sea-level rise.","PeriodicalId":247618,"journal":{"name":"VNU Journal of Science: Earth and Environmental Sciences","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115288669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the Influence of the Soil and Groundwater to the Subsidence of Houses in Van Quan, Hanoi","authors":"Dinh Xuan Vinh","doi":"10.25073/2588-1094/vnuees.4539","DOIUrl":"https://doi.org/10.25073/2588-1094/vnuees.4539","url":null,"abstract":"The area of Van Quan, Hanoi before 2004 was the rice field. Nearby, Ha Dinh water plant has  well-drilled underground water for residential activities. Van Quan's new urban area after being formed has detected many subsidences. The objective of this study is to assess the main causes of the subsidence of the houses, based on groundwater and soil. This paper applied the regression method to study the effect of soil and groundwater on the residential constructions in Van Quan urban area, Hanoi. Subsidence monitoring was carried out for 4 consecutive years, from 2005 to 2009, including over 500 subsidence monitoring points with high-precision Ni007 and INVAR gauges. A groundwater observation well is 30 meters deep at the site of the settlement. The results show a small effect of groundwater on subsidence. The characteristics of the young sediment area and the soil consolidation process are the main causes leading to serious subsidence in residential constructions in Van Quan urban area. This paper provides a different perspective on the impact of groundwater on the subsidence of residential structures within approximately 100 ha.","PeriodicalId":247618,"journal":{"name":"VNU Journal of Science: Earth and Environmental Sciences","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114715532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of Deep Learning Algorithm to Build an Automated Cloud Segmentation Model Based on Open Data Cube Framework","authors":"Pham Vu Dong, B. Thành, N. Q. Huy, Vo Hong Anh, Pham Van Manh","doi":"10.25073/2588-1094/vnuees.4441","DOIUrl":"https://doi.org/10.25073/2588-1094/vnuees.4441","url":null,"abstract":"Cloud detection is a significant task in optical remote sensing to reconstruct the contaminated cloud area from multi-temporal satellite images. Besides, the rapid development of machine learning techniques, especially deep learning algorithms, can detect clouds over a large area in optical remote sensing data. In this study, the method based on the proposed deep-learning method called ODC-Cloud, which was built on convolutional blocks and integrating with the Open Data Cube (ODC) platform. The results showed that our proposed model achieved an overall 90% accuracy in detecting cloud in Landsat 8 OLI imagery and successfully integrated with the ODC to perform multi-scale and multi-temporal analysis. This is a pioneer study in techniques of storing and analyzing big optical remote sensing data.","PeriodicalId":247618,"journal":{"name":"VNU Journal of Science: Earth and Environmental Sciences","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128359310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of Ferrate as Coagulant and Oxidant Alternative for Purifying Saigon River Water","authors":"T. T. Khôi, N. Chuong, Hoang Gia Phuc, N. Thuy, N. Huy","doi":"10.25073/2588-1094/vnuees.4425","DOIUrl":"https://doi.org/10.25073/2588-1094/vnuees.4425","url":null,"abstract":"In this study, we aimed to use ferrate as an all-in-one alternative for the removal of chlorine-consumed compositions such as organic, color, turbidity, iron, and manganese in river water for water supply purposes. Ferrate (FeO42-) was simultaneously employed as coagulant and oxidant for purification of Saigon River water in order to reduce the formation of disinfection by-products in the produced tap water. The Jartest was conducted using both ferrate for raw river water and poly-aluminum chloride (PAC) for chlorinated water to determine the optimum concentration of chemicals and pH values as well as comparing the effectiveness of ferrate and traditional coagulation with pre-chlorination technology for surface water purification. Results showed that ferrate could be used to remove organic compounds with high efficiency of 86.2% at pH 5 - 6 and ferrate concentration of 16 mgFe/L. Moreover, the removal efficiency for turbidity, color, and iron were at least 90%, indicating that ferrate would be a very promising alternative for chlorine and PAC for water purification.","PeriodicalId":247618,"journal":{"name":"VNU Journal of Science: Earth and Environmental Sciences","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133827509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of Seismuc Attribute Analysis to Reserch the Distribution of Middle Miocene Coral Reef Carbonate in Block 04-3, Nam Con Son Basin","authors":"Pham Bao Ngoc, Tran Trung Dong, T. Nghi, Nguyen Thi Thao, Tran Thị Oanh, Phạm Thị Thu Hằng, Bui Thi Ngan","doi":"10.25073/2588-1094/vnuees.4647","DOIUrl":"https://doi.org/10.25073/2588-1094/vnuees.4647","url":null,"abstract":"The seismic properties of Root Mean Square Amplitude, Maximum Amplitude, and Sum of Positive Amplitude most clearly reflect the distribution characteristics of middle Miocene carbonate sediments in ​​block 04-3, Nam Con Son basin. Middle Miocene carbonate is commonly distributed on both reflection surfaces of  P1 and P2. Within each reflective surface, carbonate sediments are concentrated around the uplifting zones, such as structures of Thien Ung - Mang Cau, Dai Hung and Bo Cau. These are completely consistent with the results of the interpretation of well-log data of Vietsovpetro, VSP [1]. The wells C-2X and C-4X  located at the edge of the uplifting zone should have the thickest carbonates. According to the results of amplitude attribute analysis, these wells are distributed in the high concentration area of carbonate formations. Meanwhile well C-1X  and well C-3X, which are near the top of the uplifting zone and further away from the uplifting structure have thin carbonate set and belongs to a low carbonate density area.","PeriodicalId":247618,"journal":{"name":"VNU Journal of Science: Earth and Environmental Sciences","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130518854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of Shoreline Changes along Upstream of Se San River, Kontum Province based Multi-temporal Remote Sensing Data Analysis","authors":"P. Thuy, Pham Viet Hoa, V. V. Tích, Pham Minh Tam","doi":"10.25073/2588-1094/vnuees.4673","DOIUrl":"https://doi.org/10.25073/2588-1094/vnuees.4673","url":null,"abstract":"Se San river upstream includes Poko tributary (on the right bank) and Dak Bla tributary (on the left bank), mostly located in Kon Tum province. The process of river sediment decline has dramatic shoreline changes in this area, which becomes a driving-force to modify the current socioeconomic development as well as the impact on territorial planning in the future. This study aims to analyze the shoreline changes by extracting multi-temporal satellite imagery of Landsat in the period of 1990-2013 and identify its change effects on land-use. The results show that the strongest erosion rate was -2.96 m/year in Dak Bla tributary (in Kon Tum town). And in the Poko tributary, the average value of erosion rate is -1.31 m/year and the average accretion rate is 1.17 m/year. In the context of dramatic land-use change, this approach allows to support for territorial management and illustrates the accretion-erosion relationship in river basin evolution.","PeriodicalId":247618,"journal":{"name":"VNU Journal of Science: Earth and Environmental Sciences","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126825735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}