Area Of Hanoi Research Articles

Evaluation of ground motion models for Northern Vietnam based on ground motion records of the 2020 Mw5.0 Moc-Chau earthquake sequence

It is challenging to select ground motion models (GMMs) for seismic hazard assessments for a region with sparse recorded data. In this study, data on the 2020 Mw5 Moc-Chau earthquake and its aftershocks were used to select an appropriate GMM for northern Vietnam (NVN). The 204 strong motion records were collected from 32 seismic stations and then used to compare eleven non-Vietnamese and two simplified Vietnamese local GMMs to assess their model prediction efficiencies. Among all the candidates, the global NGA-West2 GMMs performed the best fit with the data. Our analyses revealed the possibility of damage resulting from shaking in the Hanoi metropolitan area caused by recognized earthquake sources in NVN. In our examination of total residuals of differences between the GMM predictions and observed data, the average standard deviation from ASK14 was slightly higher than the limit accepted for modern seismic hazard assessments. ASK14 was further adjusted by the spatially varying coefficients that were derived from observations ground motion of this event. The adjusted ASK14 was used to evaluate seismic risk scenarios of large earthquakes in NVN and compared with the structures’ design spectra of the Hanoi area. To increase the prediction efficiency, additional local data are required to develop a region-specific GMM for NVN. We suggest that GMM be developed in the near future by regionalizing the ASK14 GMM according to additional local data further collected from existing broadband seismic observations and new accumulating continuous recording data from Vietnam’s broadband seismic networks.

Simultaneous analysis of certain tree-nut allergens in cookies by LC-MS/MS

In this study, four tree-nut allergens were identified using liquid chromatography-mass spectrometry (LC-MS/MS) with a reverse-phase XSelect HSS C18 SB column (100 mm x 2.1 mm, 3.5 µm) and corresponding guard column. The gradient solvent program employed 0.1% formic acid in water and 0.1% formic acid in acetonitrile, with a flow rate of 0.5 mL/min, a positive ion electrospray ionization (ESI+) source, and a multiple reaction monitoring (MRM) mode. The method was validated following the guidelines of AOAC International. Results showed that the method had good specificity, with calibration curves constructed in the concentration ranges of 30.5 - 1220 µg/g for almonds, 102 - 4080 µg/g for cashews, 128 - 5120 µg/g for hazelnuts, and 122 - 4880 µg/g for pistachios. Limits of detection were 9 µg/g for almonds, 30.6 µg/g for cashews, 38.4 µg/g for hazelnuts, and 36.6 µg/g for pistachios, while limits of quantification were 30.5 µg/g for almonds, 102 µg/g for cashews, 128 µg/g for hazelnuts, and 122 µg/g for pistachios. The repeatability and accuracy of the method met AOAC requirements. The method was used to analyze the content of four groups of nut allergens (almond, cashew, hazelnut, and pistachio) in ten cookie samples from the Hanoi area. Results indicated that three samples contained undeclared allergens on the food labels.

Semi-diurnal distribution of polycyclic aromatic hydrocarbons bound to PM2.5 and PM0.1 during pollution episode in the urban area of Hanoi.

Every year, Hanoi suffers from several episodes (periods with daily concentration of PM2.5 higher than 50µgm-3 during at least two consecutive days). These episodes are of health concern because of the high concentration of PM2.5 and/or PM0.1 and the presence of PM-bound toxic components, such as, PAHs. In this study, the concentrations of PAHs bound to PM2.5 and PM0.1 in night-time and day-time samples during episode and non-episode periods in December 2021 were determined. The concentrations of PAHs bound to PM2.5 were found to increase significantly from day-time samples of 3.24 ± 0.83ngm-3 to night-time samples of 10.8 ± 4.45ngm-3 in episode periods. However, PAHs bound to PM0.1 increased slightly from day-time samples of 0.58 ± 0.12ngm-3 to night-time samples of 0.89 ± 0.30ngm-3 in episode periods. Diagnostic ratios of PAHs indicate that biomass/coal combustion andvehicular emissionare the primary sources of PAHs. The incremental lifetime cancer risk was estimated to vary from 8.7E-09 to 2.5E-08 for children and 6.7E-08 to 2.2E-07 for adults, respectively. Accordingly, loss of life expectancy was estimated at 0.11min and 0.82min for children and adults, respectively. These findings imply that the carcinogenic impact induced by PAHs via inhalation is negligible during the episode period.

Study on the temporal and spatial distribution of Culex mosquitoes in Hanoi, Vietnam

Arboviruses transmitted by mosquitoes, including Japanese encephalitis virus (JEV), present a substantial global health threat. JEV is transmitted by mosquitoes in the genus Culex, which are common in both urban and rural areas in Vietnam. In 2020, we conducted a 1-year survey of Culex mosquito abundance in urban, suburban, and peri-urban areas of Hanoi using CDC-light traps. Mosquitoes were identified to species and sorted into pools based on species, sex, and trap location. The mosquito pools were also investigated by RT-qPCR for detection of JEV. In total, 4829 mosquitoes were collected over a total of 455 trap-nights, across 13 months. Collected mosquitoes included Culex, Aedes, Anopheles, and Mansonia species. Culex mosquitoes, primarily Cx. quinquefasciatus, predominated, especially in peri-urban areas. Most Culex mosquitoes were caught in the early months of the year. The distribution and abundance of mosquitoes exhibited variations across urban, suburban, and peri-urban sites, emphasizing the influence of environmental factors such as degree of urbanization, temperature and humidity on Culex abundance. No JEV was detected in the mosquito pools. This study establishes baseline knowledge of Culex abundance and temporal variation, which is crucial for understanding the potential for JEV transmission in Hanoi.

Strategic flood impact mitigation in developing countries’ urban road networks: Application to Hanoi

Due to climate change, the frequency and scale of flood events worldwide are increasing dramatically. Flood impacts are especially acute in developing countries, where they often revert years of progress in sustainable development and poverty reduction. This paper introduces an optimization-based decision support tool for selecting cost-efficient flood mitigation investments in developing countries’ urban areas. The core of the tool is a scenario-based, multi-period, bi-objective Mixed Integer Linear Programming model which minimizes infrastructure damage and traffic congestion in urban road networks. The tool was developed in collaboration with Vietnamese stakeholders (e.g., local communities and government authorities), and integrates data and inputs from other disciplines, including social science, transport economics, climatology and hydrology. A metaheuristic, combining a Greedy Randomized Adaptive Search Procedure with a Variable Neighborhood Descent algorithm, is developed to solve large scale problem instances. An extensive computational campaign on randomly generated instances demonstrates the efficiency of the metaheuristic in solving realistic problems with hundreds of interdependent flood mitigation interventions. Finally, the applicability of the interdisciplinary approach is demonstrated on a real case study to generate a 20-year plan of mitigation investments for the urban area of Hanoi. Policy implications and impacts of the study are also discussed.

Research on households’ willingness to pay for the options of price calculation of household solid waste management services in Hanoi

This study used the contingent valuation method (CVM) to investigate and analyse the current status of household solid waste management and evaluate people’s consensus and willingness to pay (WTP) for household solid waste collection, transportation, and treatment services among urban, rural, and mountainous areas in Hanoi. It also utilised regression analysis to assess factors affecting people’s WTP. The study surveyed a sample size of 405 households. To ensure a basis for comparison among urban, rural, and mountainous areas, the study distributed and conducted an equal number of 135 surveys in each area through random sampling. The research results indicate that the average household solid waste in Hanoi is highest in urban areas at 1.27 kg/household/day, followed by rural areas at 1.21 kg/household/day, and mountainous areas at 1.067 kg/household/day. However, most household solid waste has not been classified at the source. Regarding WTP for household solid waste collection, transportation, and treatment services, the results show that 85% of urban households agreed to pay higher than the proposed price, with an average WTP of 1,136 VND/kg. In rural households, 47% agreed to pay 778.96 VND/kg, and 11% of mountainous households agreed to pay an average of 673.04 VND/kg. These insights can guide tailored waste management pricing strategies across diverse urban and rural settings.

Assessing the effect of COVID 19 lockdowns on the composition of organic compounds and potential source of PM2.5 in Hanoi, Vietnam.

The ambient air quality during COVID-19 lockdowns has been improved in many cities in the world. This study is to assess the changes in persistent organic pollutants in PM2.5 during the COVID-19 lockdown in Hanoi. Individual organic species in PM2.5 ((e.g., polycyclic aromatic hydrocarbons (PAHs), polychlorobiphenyls (PCBs), and organochlorine pesticides (OCPs)) were measured in an urban residential area in Hanoi from before the March 10th to April 22nd, 2020, including before the partial lockdown (BL) and the partial lockdown (PL) phases. During the PL phase, the concentration of Σ14PAHs and Σ28PCBs was reduced by 38 and 52% compared with the BL period, respectively. The diagnostic ratio method implied that the sources of PAHs within the PL phase had a less effect on traffic and industrial activities than in the BL phase. The characteristic ratio method indicated that PCBs were mixed by commercial product and combustion process in both the BL and the PL periods, however, the source of PCBs in the BL phase was influenced by municipal waste incineration more than those in the PL phase. The decreasing concentration of Σ20OCPs during the partial lockdown was attributed to the restriction of human activities during the quarantine period. The results suggested that the source of OCPs was probably derived from the usage of pesticides in current and, historical degradation or the transportation of pesticides from the soil to the atmosphere.

Studying the Situation and Proposing Some Basic Solutions to Improve Psychological Harmony Between Managerial Staff and Students of Medical Universities in Hanoi Area

The students who are being trained at medical universities are the future medical staff. The quality of these personnels depends largely on the studying and training process at the university. Therein, the psychological harmony between managerial staff and students is a very important factor. It is the premise and prerequisite to lead to bonding, support, sympathy, and understanding, ultimately resulting in improving the university’s training quality. This topic focuses on studying the current situation and thereby proposing solutions to improve the level of psychological harmony between managerial staff and medical students in Hanoi.

Vietnamese health professionals' views on the status of the fetus and maternal and fetal health interests: A regional, cross-sectional study from the Hanoi area.

Obstetric ultrasound is an important tool in managing pregnancies and its use is increasing globally. However, the status of the pregnant woman and the fetus may vary in terms of clinical management, views in the community and legislation. To investigate the views and experiences of Vietnamese health professionals on maternal and fetal health interests, priority setting and potential conflicts, we conducted a cross-sectional study using a structured questionnaire. Obstetricians/gynecologists, midwives and sonographers who manage pregnant women in maternity wards were invited to participate. We purposively chose public health facilities in the Hanoi region of Vietnam to obtain a representative sample. The final sample included 882 health professionals, of which 32.7% (n = 289) were obstetricians/gynecologists, 60.7% (n = 535) midwives and 6.6% (n = 58) sonographers. The majority of participants (60.3%) agreed that "The fetus is a person from the time of conception" and that maternal health interests should always be prioritised over fetal health interests in care provided (54.4%). 19.7% agreed that the fetus is never a patient, only the pregnant woman can be the patient, while 60.5% disagreed. Participants who performed ultrasounds were more likely to agree that fetal health interests are being given more weight in decision-making the further the gestation advances compared to those who did not perform ultrasounds (cOR 2.47, CI 1.27-4.79: n = 811). A significant proportion of health professionals in Vietnam assign the fetus the status of being a person, where personhood gradually evolves during pregnancy. While the fetus is often considered a patient with its own health interests, a majority of participants did give priority to maternal health interests. Health professionals appear to favour increased legal protection of the fetus. Strengthening the legal status of the fetus might have adverse implications for maternal autonomy. Measures to restrict maternal autonomy might require close observation to ensure that maternal reproductive rights are protected.

Factors affecting the application of social responsibility accounting: Evidence from plastic manufacturing companies

Sustainable development goals (SDGs) issued by the United Nations (UN) have been recognized as the aims for sustainable development of the global economy and companies around the world. In realizing SDGs, social responsibility accounting (SRA) is gradually proving to be an effective quantification tool to enhance transparency and reliability in the social responsibility reports of companies. Therefore, this study aims to evaluate impact factors on SRA in Vietnamese plastics companies, an environmentally sensitive industry. We used a large-scale survey and collected 160 respondents from plastic manufacturing enterprises in the Hanoi area, Vietnam. It is found that three factors, namely, stakeholder pressure, awareness of business managers, and characteristics of plastic enterprises, have positive impacts on the application of SRA in plastic enterprises. Meanwhile, the environmental cost factor hinders the application of SRA. Thereby, the research makes recommendations for plastic manufacturing enterprises in an emerging country like Vietnam on how to best apply SRA to further the SDGs.

Application of Satellite Images and Artificial Intelligence to Monitor Land Cover Changes in Hanoi Area During 2013-2023 Period

Artificial intelligence (AI) and remote sensing technology have now increasingly improved their efficiency and reliability in monitoring the changes in land cover. With the amendment of the Vietnamese Law on Land in 2013 and the administrative boundary expansion of Hanoi, Hanoi experiences significant changes in land use and land cover for the last ten years. To monitor the actual land use changes in the area, this study used the Random Forest (RF) machine learning algorithm to classify the basic land covers, monitor, and analyze the spatial variation of land use and land cover in the 2013 to 2023 period. The study findings indicate a relatively high rate of expansion of construction zone area and a decrease in land cover related to water bodies and vegetated area. Water bodies decrease by an average of 0.8% annually, whereas the construction zone area increased by 7% of the total area.

Intention to use digital transformation of human resource employees in Hanoi

Digital transformation is at the heart of the fourth industrial revolution, which leads to fundamental and far-reaching changes in business operations. In an environment where all fields and industries are undergoing digital transformation, are human resources employees willing to accept and implement digitalization in their daily work, and what factors influence their intention to use digitalization in their work? The article studies 130 human resources staff at businesses in the Hanoi area. Research results confirm that perceived usefulness, perceived ease of use, and perceived self-efficacy about digital transformation have a positive influence on human resources employees' intentions to use digital transformation at work. For human resources staff to be comfortable in the process of using technology in a digital transformation environment, human resources employees need to be guided and trained on how to apply new applications and new technology in the field of human resources.

Service Quality and Performance Results through Customer Satisfaction at Small-Scale Hotels in Hanoi Area

In the context of the Covid-19 pandemic, the hotel industry in Vietnam shows a strong recovery, businesses are continuously stepping up recruitment activities, expanding markets and increasing customer files. . The goal of the article is to clarify the impact of service quality on operational results through customer satisfaction. The research sample was collected by the author of the article from 119 survey questionnaires after 3 times distributing questionnaires to customers who used services at 5 small-scale hotels in the Hanoi area of ​​Vietnam. Using quantitative research on the PLS-SEM linear structural model on SPSS 20 and AMOS 20 software, the results have identified 3 groups of recommended solutions for hotel managers in meeting demand. customers and improve operational results, including: (i) Organizing hotel staff, foreign language training, and professional behavior; (ii) Invest in equipment and facilities suitable to customer needs in different stages; (iii) Increase customer responsiveness, especially through the internet channel.

Analyzing flood characteristics and establishing a monitoring network for the red river area of Hanoi

Flooding is a phenomenon in which river water rises during the rainy season (in the North of Viet Nam from June to September every year), causing flooding in some alluvial grounds outside the Red River dyke in the Hanoi area. This phenomenon occurs frequently with different scales in area and depth of flooding, which depends on the hydro-meteorological conditions of the entire region of Red river and the ability of flow regulation structures and flood drainage on river. The impacts of flooding due to rising river levels not only cause instability in daily life in residential areas but also change river dynamics and cause increased water pressures and seepage pressures on the dikes. Currently, flooding can be largely controlled by regulating the flow of rivers through hydroelectric dams in upstream areas. However, establishing a flood monitoring network and creating a database to assess the impact of flooding is necessary to minimize damage and improve the efficiency of exploitation and use of the Red River. This article focuses on research on flood risk assessment and the basis for establishing a flood monitoring network on the Red River in the Hanoi area to serve sustainable exploitation of the territory.

Diversity and larval habitats of mosquitoes (Diptera: Culicidae) in urban areas in Ha Noi, Vietnam

Although some mosquito-borne diseases have been thriving in Ha Noi city, Vietnam very few studies on mosquitoes have been conducted. Determining how the species composition and abundance of mosquito vectors depend on environmental resources in different habitats addresses where different types of vector control need to be applied. The present study aims to investigate the characteristics of larval habitats and to provide a composition of mosquitoes (Culicidae) in this city. Surveys of larval and adult mosquitoes were carried out from different habitats in urban areas during rainy seasons from 2018 to 2023. Overall, in almost all water containers that were surveyed (80.9%), immature mosquitoes were present. A total of 4593 mosquitoes including 3,950 larvae and 643 adults were collected from 16 sampling sites. Twelve mosquito species belonging to 6 genera were collected and identified. Aedes albopictus and Culex quinquefasciatus were the most common and abundant species, each accounting for 34% of the total collected larval specimens. Five species, Anopheles umbrosus, Culex cintellus, Armigeres subalbatus, Mansonia annulifera, and Lutzia fuscana were the first records for Ha Noi city. The species composition varied between different habitat types. Peri-domestic habitats were the most common breeding sites for mosquitoes in the study area. Noteworthy, species belonging to genus Aedes were abundant in domestic habitats created by anthropogenic materials while that of genus Culex was mainly thriving in large water bodies in both peri-domestic and natural habitats. The current results show a variation in the distribution and abundance of mosquitoes in urban areas of Ha Noi which should be considered for effective planning and implementing mosquito control programs in the city.

Preliminary Investigation of Microplastic Pollution in Agricultural Soil in Dong Anh District, Hanoi City

Microplastics are a growing concern in the environments and especially agricultural soil due to numerous negative impacts on the ecosystems and human health. This study aimed to investigate the properties of microplastics (including quantity, shape, size, and polymer types) in five samples (DA1-5) taken from agriculture soil in Dong Anh district, Hanoi using Nicolet iN10 MX Fourier transform infrared (µFTIR) microscope. The study found that the microplastic content in these soils ranging from 494 ± 292 items/kg dry weight to 1031 ± 379 items/kg dry weight. In terms of shape, microplastic fragments accounted for the majority of microplastics found in soil (65% - 86% of the total microplastics). Fifteen types of microplastic polymers were identified in the soil samples, with PET being the most common polymer of 38%, followed by urea-formaldehyde resin of 15%, and nylon of 13%. Microplastics with sizes ranging from 50-150 µm were the dominant group (39% - 57% of the total microplastics). This study provides an initial assessment of the presence of microplastics in the agricultural soil of the suburban area of Hanoi, highlighting the potential risk of contamination that may effect on environment and pose a threat to human health.
 
 

Modelling migration of ammonium ion through landfill bottom barriers subjected to elevated temperature and dry-wet cycles, a case study in southern Hanoi, Vietnam

Geosynthetic clay liners and compacted clay liners are common bottom barriers in landfills. One of the important steps in barrier design is to evaluate the effectiveness of the bottom barrier system in practical conditions based on modelling contaminant migration. This study simulates the migration of ammonium ions through proposed bottom barriers for design under consideration of the southern Hanoi area’s temperature and geohydrology conditions, then evaluates potential impacts on normalized ammonium concentration in groundwater. Proposed bottom barriers include geosynthetic clay liner and compacted clay liner constituting from local soils. The results indicated the reclamation of locally natural soils and geosynthetic clay liner (GCL) placement was approximately 5.2 and 13.4 times more effective in slowing ammonium migration than natural soil, respectively. Compacted clay liner of natural soils exhibited few impacts from elevated temperature. However, being sensitive to an elevated temperature at 50°C, the barrier performance of GCL caused the peak normalized ammonium concentration in groundwater to be 4.2 times higher than normal conditions. Notably, normalized ammonium concentration in groundwater increased 29 times when the geosynthetic clay liner was exposed to 2 dry-wet cycles with ammonium solution. These results provided useful references for designers and engineers to consider in selecting barrier materials in the new landfill.

PREDICTING TEMPERATURE DISTRIBUTION IN HANOI REGION'S ASPHALT PAVEMENT THROUGH NUMERICAL SIMULATION

This article presents determining the temperature distribution in asphalt pavement in the Hanoi area based on numerical simulation using FEM. Climate data were collected from freely available online data from the Federal Highway Administration of the United States. From this data, the surface temperature of the pavement was calculated, which served as the boundary condition for the heat transfer problem of the pavement. The results show that the pavement surface temperature is typically highest around 11 a.m. to 12 p.m., while the lowest temperature is typically around 4 a.m. to 6 a.m. The temperature inside the pavement layer is usually high between 10 a.m. and 4 p.m. when the strength and deformation resistance of the pavement are relatively low. In contrast, the temperature inside the pavement is low during the period between midnight and 6 a.m., when the asphalt concrete becomes brittle and is easy to crack. The analysis of the temperature distribution in the pavement structure can be used for calculating and designing the pavement, as well as predicting pavement rutting.

Metropolisation, migrations and urban civilisation: the example of Hanoi

With 38% of its population living in cities, Vietnam is in the process of completing its urban transition. The arrival of populations from the countryside coupled with a process of spatial sprawl is part of the urban catching up that the country has been doing since the liberalization of its economy at the end of the 1980s. Poles of concentration of value and population are rapidly being formed: the metropolises. The Vietnamese metropolises, starting with the capital city-province of Hanoi, are the vehicle and modus operandi of the country's transition to a market economy, and they crystallize a number of social tensions linked in particular to the entrenchment, or even the clash, of rural and urban cultures. The purpose of this article is to see how, in the peri-urban area of Hanoi, an observation post for the advance of the city over the countryside, the urban civilization program is being called upon by the authorities to promote urban modernization based on social harmony and a certain vision of urban sociality.

Intention to Withdraw Lump-Sum Social Insurance in Terms of Demographics and Implications for Policy Revision in Vietnam

The main objective of this study is to identify, evaluate and analyze the intention to withdraw lump-sum social insurance of participants in the suburban areas of Hanoi. Previous studies have examined the influence of factors on intention to withdraw or retire early. However, demographic characteristics have received little attention, especially for the workers in the industrial zones. Through a quantitative survey study using convenience sampling with a small survey including 238 employees and workers currently working in the suburban areas of Hanoi, Vietnam. This study uses tools statistics, Cronbach's alpha analysis, factor discovery analysis, and ANOVA analysis. Research results show no difference in intention to withdraw money in different gender groups, but age, working sector, time participating in social insurance contributions, and income all show differences. The research results suggest some implications for policy agencies in amending the legal provisions on social insurance to increase the coverage rate for the social insurance system in Vietnam in the current context