Hanoi University of Natural Resources and Environment

Land is the fundamental basis for maintaining agricultural production and ensuring food security. The task of managing and sustainably utilizing land resources has always been a priority for every country in the world. The study used GIS-MEC technology to integrate data from seven types of single-factor maps to construct a soil quality map with 47 land units (including eight land units with an area >100 ha, 29 land units with an area from 10 to 100 ha, and 10 land units with an area <10 ha). In addition, by combining soil quality maps and the nutritional needs of different crops, an assessment of land suitability for six major crops was conducted, and three key crops were selected for focused development: rice, vegetables, and flowers. The application of GIS in soil quality management is in line with the current trends of digital transformation and integrated data management in Vietnam and around the world. However, this method has several limitations that need to be considered when applying it, such as dependence on expert expertise, high demands on input data and verification of output results, and limitations in analyzing trends and analyzing social, non-linear factors.

This study evaluates the forecasting performance of the Integrated Forecasting System (IFS) model developed by the European Centre for Medium-Range Weather Forecasts (ECMWF) in predicting tropical cyclones (TCs) affecting Vietnam during the period 2018–2022. The assessment focuses on TC track, intensity, and rainfall forecasts, employing best-track data from the Regional Specialized Meteorological Center (RSMC) Tokyo and rainfall observations collected from 186 meteorological stations across Vietnam. The results show that the mean direct position error (DPE) increases with forecast lead time, from 71 km at 24 hours to 118 km at 48 hours and 183 km at 72 hours. A statistically significant downward trend is observed at the 48-hour forecast horizon, indicating improvement in track accuracy. Overall, these errors remain within the acceptable operational thresholds for Vietnam, confirming the model’s applicability for routine forecasting. In terms of TC intensity, forecast errors show limited variation across different lead times, with the mean absolute error (MAE) of Vmax averaging 9 knots (4.63 m/s) and the root mean square error (RMSE) of Vmax averaging 12 knots (6.17 m/s). Both values are consistent with national standards; however, a few cases exhibited substantial deviations, particularly for rapidly intensifying cyclones. For TC-induced rainfall, the IFS model demonstrates the highest skill in forecasting light rainfall (<16 mm) across all lead times, whereas predictive skill declines notably for heavier rainfall categories. At a 72-hour lead time, both the threat score (TS) and the probability of detection (POD) drop below 0.10 for rainfall exceeding 50 mm, underscoring considerable limitations in forecasting heavy and very heavy precipitation events.

Estuarine environments are highly productive and biodiverse ecosystems that are particularly vulnerable to environmental pollution. This study assessed the presence and ecological risks of microplastics (MPs) and ten heavy metals in surface sediments from two major estuaries of the Red-Thai Binh River system in northern Vietnam: Ba Lat and Bach Dang. Sediment samples were collected during the rainy season (July 2024) under low tide conditions. The average concentrations of heavy metals followed the order: Hg < Cd < As < Ni < Cu < Cr < Pb < Zn < Mn < Fe. While most metal concentrations, except for Fe, were below Vietnamese regulatory limits (QCVN 43:2025/BTNMT), several samples exceeded the U.S. EPA (1997) Threshold Effects Level (TEL), particularly for As, Pb, Hg, Cu, and Ni. The geo-accumulation index identified Pb as the most enriched element, followed by As and Zn. Despite localized exceedances, the overall ecological risk associated with heavy metals was classified as low. In contrast, microplastic contamination posed a more prominent ecological threat. MP concentrations ranged from 3,600 to 9,000 items/kg (mean: 5,908±1,790) in Ba Lat and from 1,900 to 4,800 items/kg (mean: 3,858.3±832.8) in Bach Dang, surpassing levels reported in previous regional studies. The dominant particle types were small-sized fibers (< 2 mm) and fragments (0.05–0.2 mm²), which are likely to have greater bioavailability and ecological impact. A Potential Ecological Risk Index (PERI), incorporating MP abundance, polymer types, and hazard scores, indicated high-to-dangerous risk levels in Bach Dang and medium-to-high risk levels in Ba Lat. These findings highlight the urgent need for effective mitigation strategies, including improved plastic waste management and routine MP monitoring, particularly in ecologically sensitive areas such as aquaculture zones, coastal habitats, and salt production sites.

In the era of the digital economy, online shopping has become an indispensable part of daily life. Particularly in the modern context, the Consumer-to-Consumer (C2C) e-commerce model is increasingly prevalent. However, the enormous amount of information on C2C platforms makes it difficult for consumers to make decisions that match their needs and budgets. To support consumers in selecting optimal products, this study applies an integrated Pareto – Fuzzy – AHP – TOPSIS model to analyze consumer behavior on C2C e-commerce websites toward green consumption, thereby helping users optimize online purchasing decisions.

Transitioning from traditional smallholder to large-scale, mechanized rice farming offers significant potential for reducing greenhouse gas (GHG) emissions in Southeast Asia. This study assessed the environmental and economic performance of large-scale OM4040 rice cultivation in the Mekong Delta, Vietnam, using IPCC methodologies. Results showed a 15.5% reduction in CO₂-equivalent (CO₂e) emissions per ton of rice produced, driven by improved water management (e.g., alternate wetting and drying), laser-assisted land leveling, and optimized fertilizer use. Mechanized operations were found to increase fuel-based emissions, but higher yields offset this effect. Additionally, postharvest straw reuse contributed to avoiding 2.4–3.0 tons CO₂e per 10 ha per season, reinforcing circular economy principles. Economically, large-scale systems were more profitable only when land rental costs were excluded. The integration of carbon efficiency and sustainability indices provided a comprehensive evaluation of emission trade-offs. These findings support the adoption of climate-smart rice production systems and underscore the need for enabling infrastructure and land policy reforms to enhance scalability and sustainability.

This study explored the effectiveness of podcasts in enhancing English listening comprehension among first-year university students in Vietnam. A quasi-experimental design was employed with 60 participants divided into control and experimental groups. While the control group engaged in traditional listening activities using textbook-based materials, the experimental group practiced listening through curated podcast content over an eight-week period. Pre- and post-tests were administered to assess gains in listening proficiency. The results indicated a statistically significant improvement in the experimental group’s performance. Qualitative feedback gathered from reflective journals further supported these findings, revealing increased learner autonomy, motivation, and engagement with authentic language input. The study underscores the pedagogical value of integrating podcasts into language instruction, especially in contexts with limited access to native speaker interaction and authentic materials. Recommendations for instructional practice and future research are discussed.

Khauau gold deposit, Binhvan commune, Chomoi District, Backan Province, Vietnam, is located in the Dong Bac Bo intracontinental orogenic belt. This is one of the important gold mineralization areas of Vietnam. To study the zonation of mineralization and to predict the prospect of deeply hidden buried gold ore, a research was conducted based on mineral facies analysis, fluid inclusion thermometry, ICP-MS chemistry, and morphological orebody size. The results indicate that the gold mineralization is derived from medium to medium–low temperature hydrothermal fluids associated with deep-seated formations. Inclusion homogenization temperature is from 170 to 310o C, and the main ore mineral components include pyrite, arsenopyrite to a lesser extent galena, sphalerite, and chalcopyrite. Gold mineralization-quartz-sulfur Khauau deposit is divided into three zones, which from the top to the bottom is as follows: ore zone 1 is gold-quartz-pyrite poor sulfur; ore zone 2 is gold-quartz-polymetallic; ore zone 3:is gold-quartz-arsenopyrite and pyrrhotite. Ore bodies are likely located at the depths of 125 to 540 m with many extending beyond 400 m. The depth of ore-forming processes is 562 m and the zoning coefficient of Kz= 0.83. Accordingly, it is possible to predict the prospect of the Khauau gold deposit, Binhvan commune, Chomoi District, Backan Province, to a depth of more than 500 m, and possibly extend to depths of up to 5 km.

ABSTRACTWe study the split common solution problem with multiple output sets. To solve this problem, we propose two new algorithms based on the contraction projection method. We establish a weak convergence theorem for the first one and a strong convergence theorem for the second. Our algorithms do not require information about the strong coefficients of the cost operators and the norm of the transfer mappings. Some applications of the main theorems for solving related problems are also presented. Two numerical examples are given to illustrate the effectiveness of the proposed algorithms.