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Comparison of Two Versions of SWAT Models in Predicting the Streamflow in the Xuanmiaoguan Reservoir Catchment
2022
Huijuan Bo, Xiaohua Dong, Zhonghua Li, Gebrehiwet Reta, Lu li | Chong Wei
Correct streamflow prediction is critical for determining the availability and efficiency of watershed spatial plans and water resource management. In the Xuanmiaoguan (XMG) Reservoir Catchment, two different versions of the Soil and Water Assessment Tool (SWAT) model are compared to discharge predictions. One version is the Topo-SWAT, in which the overland flow is generated by saturation excess (Dunne) runoff mechanism, while the other is driven by infiltration excess runoff mechanism, i.e., the Regular-SWAT. These SWAT models were calibrated and validated with discharge at daily and monthly steps, and then, the annual runoff volume and spatial distribution of runoff generation areas were also discussed. At the monthly scale, the un-calibrated Topo-SWAT model outperformed the un-calibrated Regular-SWAT model throughout the whole time (2010-2016). The Nash-Sutcliffe efficiency coefficients (NSE) using Topo-SWAT and Regular-SWAT were 0.59, 0.58 for calibration and 0.69, 0.72 for validation for daily streamflow, and 0.69, 0.65 for calibration and 0.73, 0.88 for validation for monthly streamflow, respectively, based on the parameter sensitivity analysis results. There was a 5-year understatement for yearly runoff volume using Regular-SWAT, but a 4-year underestimation using Topo-SWAT, which had a different year in 2015. Regular-SWAT and Topo-SWAT have significantly different geographical distributions of runoff generating locations within the watershed for one occurrence (greater rainfall). The findings reveal the most accurate contributing regions for runoff generation in the research catchment, allowing for more effective implementation of best management techniques (BMPs).
Afficher plus [+] Moins [-]Hydraulic Performance and Energy Loss Effect of Pit Structure Optimized Drip Irrigation Emitter
2022
Tianyu Xu, Shuteng Zhi, Qiuyue Yu | Ennan Zheng
The pit structure optimized drip irrigation emitter (PODE) is a novel type of irrigation emitter that may provide shunts, quick diversion, and mixed flow to maximize energy loss. To study the influence of the geometric parameters of the flow channel on the hydraulic characteristics and energy loss effect, twenty-five sets of orthogonal test schemes were established. Using numerical simulation and verification tests, the flow index and energy loss coefficient were obtained. The results showed that the flow index of the PODE was 0.4632-0.5265, and its hydraulic performance was good. The energy loss coefficient under the pressure head of 5-15 m was 510-2221, which showed that the energy loss effect was obvious. The influence order of the geometric parameters on the flow index was B>P>C>D>A, the optimal solution was P0.6D1.4A85B0.25C0.12. The determination coefficient of the regression model based on geometric parameters and flow index was 0.85. In addition, the verification test showed that the relative error among the test value, simulated value, and estimated value were less than 5%, and the flow index can be estimated reliably. The research can provide a reference for the pre-research and evaluation of the hydraulic performance and energy loss effect of the PODE.
Afficher plus [+] Moins [-]Preparation of Silver and Copper Co-impregnated Nano-ZnO Immobilized on Mesoporous SiO2 and its Photocatalytic Performance
2022
Qinlin Yuan, Hang Xu, Shaokang Wang, Zhewen Yang, Wenke Zhang | Qinggao Ma
To improve light usage, Ag and Cu were co-impregnated with nano-ZnO, and the mesoporous silica gel (meso-SiO2) was chosen as the carrier. The sol-gel method was used to successfully construct a composite photocatalyst with 3 percent Ag/0.1 percent Cu/nano-ZnO/meso-SiO2. For the evaluation of the photocatalytic activity of the as-prepared catalysts, Reactive Black 5 was used as a simulated organic pollutant in aqueous. The results revealed that uniform spherical nano-ZnO particles with a diameter of 10 nm were attached to the surface and mesopore of meso-SiO2. The average pore width and specific surface area of this composite were 7.06 nm and 305 m2.g-1, respectively. The optimal amount of loaded Ag and Cu were 3% and 0.1%, respectively, which resulted in around 100% removal of Reactive Black 5 after 280 min UV-light irradiation. The degradation process followed pseudo-first-order kinetics. Ag and Cu-loaded nano-ZnO/SiO2 could be advantageous for suppressing the recombination of photo-generated holes and electrons, thus improving the degradation efficiency. The constant of degradation rate and adsorption equilibrium of 3%Ag/0.1%Cu/nano-ZnO/meso-SiO2 were 0.049 min–1 and 2.14 L.g-1, respectively. After three reuses, the Ag/Cu/ZnO/meso-SiO2 photocatalyst remained very stable during the photocatalytic process with no loss of photocatalytic activity. According to the GC-MS results, a probable degradation mechanism was estimated.
Afficher plus [+] Moins [-]Study on Spatiotemporal Characteristics of the Impacting Factors of Agricultural Carbon Emissions Based on the GTWR Model: Evidence from the Yellow River Basin, China
2022
Haifeng Huang | Ni Zhu
Scholars have turned their attention to the ecological protection and high-quality development of China’s Yellow River Basin in recent years. The basin is a major agricultural production area in China, hence investigating agricultural carbon emission reduction strategies in the basin is crucial. The research object in this article is the agricultural departmen.ts of China’s nine provinces in the Yellow River Basin from 2005 to 2018. Agricultural carbon emissions are measured using agricultural land usage, rice planting, crop planting, straw burning, and livestock breeding as agricultural carbon sources. In addition, the GTWR model is used to examine the spatiotemporal aspects of the impact of five factors on agricultural carbon emissions in this paper. The findings reveal that the five factors have varying degrees and directions of influence.
Afficher plus [+] Moins [-]Towards a Framework for Sustainable Municipal Solid Waste Management: The Case of Swakopmund Municipality, Namibia
2022
Timoteus Kadhila | Martin P. de Wit
If municipal solid waste (MSW) is not properly managed, harmful environmental consequences are imminent. MSW materials are rarely wasted in many affluent countries, but rather are kept in the economic cycle through circular economy models. While in many developing countries, MSW materials are discarded with little to no effort of repairing or recycling. Moving to a circular economy will drastically reduce the amount of waste currently disposed of. This study examines how the Swakopmund Municipality in Namibia’s present municipal solid waste management techniques could be adjusted toward sustainability to reap environmental and socioeconomic benefits from the trash. Source reduction, separation at source, and recycling are some of the most effective strategies in the circular economy models that will help achieve the United Nations (UN) Sustainable Development Goals (SDGs). Swakopmund Municipality should invest in infrastructure, techniques, and programs that are within the circular economy model as an emerging system for sustainability.
Afficher plus [+] Moins [-]Delineation of Groundwater, Drought and Flood Potential Zone Using Weighted Index Overlay Analysis and GIS for District Patna, Bihar, India
2022
Nikhilesh Gaurav | Geeta Singh
For groundwater evaluation, delineation, discovery, and resource management in drought and flood zones, the geographical information system (GIS) has a wide range of uses. For the study area, various thematic layers were prepared, such as a digital elevation map (DEM), geomorphology, LULC, soil, drainage density, precipitation, and slope. The thematic layers were combined using the WIOA technique. The possible areas for groundwater have been demarcated into four zones: 1-poor, 2-moderate, 3-good, and 4-very good. In the eastern parts of the district, very strong (GWPZs) were found, while in the west and mid regions, moderate and bad categories were found. Drought and flood potential danger areas were divided into four zones: 1-no risk, 2-low risk, 3-moderate risk, and 4-high risk. In the middle part of the region, there was a higher risk of drought and a reduced risk of flooding in the eastern part of the area, an elevated risk of flooding in the eastern part of the area, and a lower to no risk of flooding in the western and central regions. The groundwater, drought, and flood potential zonation map built in the present study will be useful for scholars, and implementers in exploring appropriate water exploration locations and implementing resource utilization.
Afficher plus [+] Moins [-]Elimination of Greenhouse Gas Emissions by Utilization of Industrial Wastes in High Strength Concrete for Environmental Protection
2022
R. Divahar, K. Naveen Kumar, P. S. Aravind Raj | S. P. Sangeetha
Greenhouse gases prevalence in the atmosphere is a primary reason for global warming. The cement manufacturing sectors are a significant producer of greenhouse gases, contributing one metric tonne of carbon dioxide into the environment for every metric tonne of cement produced. The heat of concrete is increased by several degrees during the pozzolanic reaction, and CO2 is released. The development of binary and ternary cementitious systems has minimized the unfavorable reactions of conventional cementitious materials. Metakaolin and alccofine, two mineral admixtures derived as waste products from industries, were used as cement substitutes in this study. The compressive strength of alccofine was compared to a metakaolin-based high strength eco-friendly concrete mix of grade M50 in an experimental investigation. In the case of binary and ternary blended cementitious systems with alccofine and metakaolin, twelve alternative mix proportions were tested, ranging from 0 to 20% in 5% increments. Based on the observed mechanical characteristics of concrete, it was discovered that the optimum replacement of alccofine was 15% and metakaolin was 5% by volume of cement in the binary cementitious system. Similarly, in the ternary cementitious system, replacing 15% alccofine with 5% metakaolin in the cement mixture results in the greatest increase in compressive strength when compared to the other experiments. As a result, it is concluded that using extra cementitious materials in concrete with mineral admixtures such as alccofine and metakaolin results in significant cost and energy savings, as well as a notable reduction in environmental pollution.
Afficher plus [+] Moins [-]Interpretive Structural Modelling (ISM) of Enablers Affecting Green Accounting in Indian Manufacturing Sector: A Conceptual Model
2022
Anjali Singh, Archana Singh | Biju G. Pillai
Green accounting is vital for every economy in the world. Indian manufacturing sectors are regarded as one of the most significant contributors to environmental and socioeconomic problems, and as a result, the country lacks global sustainability and progress. This paper focuses on how these industries can contribute to the sustainability of the environment. The paper aims to analyze how these industries can promote ecopreneurial behavior. Also, the researchers and expert opinions lead to a theoretical framework and conceptual model using a well-defined and explained literature review and the derived model to understand, observe, and analyze various environment awareness concerns. To gather the expert opinions, various calls and surveys were scheduled with chartered accountants, academicians, environmental experts, commerce people, to understand how the identified variables are influenced by each other. Environmental management accounting and green accounting came out as the most significant and vital factors. All the identified variables were complementing. Three levels came out for the model. The authors created an ISM on factors affecting green accounting in the Indian manufacturing sector, emphasizing the context and concept related to the discovered variables that have been tested in the real world.
Afficher plus [+] Moins [-]Estimating the Potential of Carbon Sequestration in Tree Species of Chintapalle Forest Range, Narsipatnam Division, Visakhapatnam, Andhra Pradesh, India
2021
Korra Simhadri, Syam Kumar Bariki | A.V.V.S. Swamy
The potential of carbon sequestration of tree species in the Chintapalle forest range, of Narsipatnam Division, was estimated by using a non-destructive method. The sequestration of 6033 trees belonging to 22 species was investigated; the approximate height of tree species and the diameter at breast height (DBH) were measured for the estimation of CO2 sequestration. The maximum weight of carbon was observed in Pongamia pinnata (L.) Pierre species i.e (37987.06 kg) and the minimum weight of carbon was noted in Phyllanthus emblica L. species i.e is (61.8kg). The total carbon sequestrated by the entire tree species was (2370614.0 kg), The average carbon sequestered was (39865.81 kg). The highest sequestration was noted in the species P. pinnata (L.) Pierre i.e. (139271.95 kg) and the lowest (226.79 kg) was noted in the species P. emblica L. The maximum average DBH with maximum carbon sequestration potential was observed in Ficus benghalensis L. species, with higher total green (AGW) observed in all sites, whereas minimum average DBH with minimum carbon sequestration potential was noted in Bambusa vulgaris species. The regression analysis tests the relationship between two variables. The height of trees has no significant impact on the amount of CO2 sequestered F (32085087175.84, 12946607900) = 2.478262; P ≥ 0.05, which indicates that the tree height plays an insignificant role in CO2 sequestration (β = 2713.28 P ≥ 0.05). The dependent variable CO2 sequestered was also regressed on the predictor variable soil organic carbon (SOC) to test the relationship. SOC insignificantly predicted CO2 sequestrated F (5.83, 2.62) = 0.2236; P ≥ 0.25, indicating that the SOC has an insignificant role in CO2 sequestration (β = 102780.3 P ≥ 0.05). Insignificant relation was observed between the parameters SOC and height of tree species to the rate of carbon dioxide sequestered, and gave a regression equation of y = 10278x + 50863 with R2 = 0.100; y=2713.285803x-209800.8762 with R2 = 0.553 respectively.
Afficher plus [+] Moins [-]Disaster Management: Tsunami and Remote Sensing Technology
2021
Sudhir Kumar Chaturvedi
Remote sensing technology has changed the way disasters like earthquakes and tsunamis are detected, monitored, and mapped in recent years. This paper summarizes the general theoretical study of Tsunami generation, propagation, and its inundation for deep, intermediate, and coastal waters. Tsunami is a Japanese word, which is made up of two words: “tsu” means harbor, and “nami” means waves. It means that Tsunami is the coastal gravity waves, which propagate close to the coastline. This analysis presents a novel method to explore the effects of tsunami waves on coastal areas. The methodology includes remote sensing nearness examinations and alteration identification strategies in remote sensing to outline a number of support routes along the coast and divide them into four homogenous sub-regions. The adjustments in the land spread are then measured in these sub-regions when the tidal wave occurs. The proposed paper gives a more solid and exact method than ordinary strategies to assess spatial examples of harmful territories through various land qualities along the coastline. The generative phase of tsunami development comprises the creation of an early disruption at the surface of the ocean due to the earthquake-generated distortion on the seafloor. Various comparative studies are also carried out using spatial technology to examine tsunami routes around the globe, taking into account the most recent tsunami occurrences.
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