Health Risk Assessment for the Exposure of Workers to BTEX at the Gasoline Stations

The study was conducted to assess the health risks of workers due to exposure to toxic gases including benzene, toluene, ethylbenzene, m, p-xylene, o-xylene, formaldehyde and acetaldehyde at gasoline retail stations. In this study, data on the  concentrations of the toxic gases were collected from the previously published studies in the qualified scientific journals. The health risk assessment was followed by the process of the United States Environment Protection Agency (U.S. EPA). The results show that the concentrations of benzene, toluene, ethylbenzene, m, p-xylene, o-xylene, formaldehyde, and acetaldehyde were in the range of 12.40 - 357.5, 12.47 - 574.17, 2.05 - 156.5, 4.57 - 218, 2.36 - 77.04, 3.64 - 153.93 and 1.27- 27.83 µg/m3 , respectively. Life time cancer risk for gasoline station workers due to exposure to benzene, ethylbenzene, formaldehyde, and acetaldehyde was calculated in the ranges of 2.13x10-5 - 6.14x10-4 , 4.96x10-7 - 3.79x10-5 , 4.81x10-6 - 2.03x10-4 , and 7.99x10-7 - 1.75x10-5 , respectively. For non-carcinogenic  compounds, the hazard index due to benzene, toluene, m, p-xylene, o-xylene were respectively in the range of 0.13 - 3.81, 7.97x10-4 -  0.04, 0.01 - 0.70 and 0.01 - 0.25. The findings revealed that there is high risk of cancer and non-cancer for the workers working at the gasolines stations if they are not taking good preventive measures. The calculation showed that the limit levels of benzene, toluene, ethylbenzene, xylene, formaldehyde and acetaldehyde should be reduced to 5.82x10-4 , 15.64, 4.13x10- 3 , 0.31, 7.57x10-4 and 1.59x10-3 mg/m3 , respectively to meet the safety levels for the workers at the gasoline stations. Keywords: benzene, toluene, ethylbenzene, xylene, formaldehyde, acetaldehyde, life-time cancer risk, healt

Digital transformation responsibilities to the Covid-19 pandemic of some countries and experiences for Vietnam

Singapore, China, and Japan are the leading countries and create inspiration for development and digital transformation for the continent in particular and the world in general. The Covid-19 pandemic has strongly promoted the digital transformation process of the above countries, so it is important to learn from the experiences of Singapore, China, and Japan in digital transformation in response to the pandemic, and economic recovery is extremely urgent. This article is qualitative research based on a secondary data set collected from the General Statistics Office of Vietnam, the World Data Bank (World Bank) and the General Administration of Customs of China, will analyze the digital transformation process of Singapore, China, and Japan with aspects of Digital Society, E-Government and Digital Infrastructure, Digital Economy. Thereby synthesizing experiences and proposing development lessons for Vietnam to transform success, economic recovery, overcoming the pandemic, and strong and sustainable growth in the post-Covid-19 period

Optimal Selection of Number and Location of Meteo-Hydrological Monitoring Networks on Vu Gia – Thu Bon River Basin using GIS

Meteorological data play a particularly important role in hydrologic research because the climate and weather of an area exert a profound influence on most hydrologic processes. Meanwhile, hydrological data are critical for performing a range of purposes, including water resources assessment, impacts of climate change and flood forecasting and warning. It can be said that the prevention of disasters caused by floods and droughts would be impossible without rational forecasting technology based on an understanding of the rainfall-runoff phenomenon and statistical analysis of past hydrological data, which cannot be achieved without meteo-hydrological observations. The lack of adequate meteo-hydrological data affects the ability to model, predict and plan for catastrophic events such as floods and droughts which have obvious negative impacts on public health and socio-economic aspects. The accurate estimation of the spatial distribution of meteorological and hydrological parameters requires a dense network of instruments, which entails large installation and operational costs. It is thus necessary to optimize the number and location of meteo-hydrological stations. This paper presents a GIS-based approach to establishing an optimal meteo-hydrological station network on Vu Gia- Thu Bon river basin for developing an up-to-date real time flood warning system. Based on statistical analysis of the annual rainfall total data at 9 existing gauges in the study area from 1980 to 2013, it showed that the error of the existing network was about 7.47%. Considering 9 rain gauges as a standard representative of rainfall over the region, if the error decreases from 7.47% to 5%, the number of additional rain gauges should be 20. For adequate and economical network design, these additional rain gauges were spatially distributed between the different isohyetals after considering the relative distances between rain gauges, their accessibility, personnel required for making observations using multi-layers analysis and spatial interpolation. For hydrological stations, based on consideration existing network with the requirements set out by the flood warning system, the number of stations should be five. In terms of spatial distribution, three stations were distributed across two main tributaries of Vu Gia- Thu Bon river basin, behind the dams for water discharge calibration and the others were located on downstream for water stage calibration. The results of the study provided a scientific approach can be applied to optimizing the meteo-hydrological station network over the river basin

RECONSTRUCTION OF DIVACANCY IN ZIGZAG-BUCKLED SILICENE NANORIBBONS

In this study, we use a tight binding model to investigate structural and electronic changes in zigzag-buckled silicene nanoribbons (ZBSiNRs) with two vacancies at different positions. We divide the defects into two categories based on a difference in geometric properties. The results show that the first- and second-order interaction parameters of two atoms of the same type play an important role in the electronic properties of this material. Vacancies near the edge have a stronger effect than those near the center of the ribbons. We further show that each type of divacancy will give a different result under the influence of a perpendicular electric field. This is a favorable condition for controlling the conductive state of materials in future applications in the semiconductor and thermoelectric industries

DIFFICULTIES IN STUDYING TOEIC LISTENING COMPREHENSION OF NON–ENGLISH MAJORED FRESHMEN AT TAY DO UNIVERSITY, VIETNAM

TOEIC Certificate is becoming more and more popular all over the world in general and in particular, Vietnam. It is considered as one of the most compulsory demands for graduating university, especially at Tay Do university. Listening seems to be a skill that many students usually face difficulties in learning. Therefore, the survey research “Difficulties in studying TOEIC Listening Comprehension of non – English majored freshmen at Tay Do University” was conducted to figure out common difficulties in studying TOEIC listening of non-English majored students. Freshmen of Bachelor of Tourism and Travel Management class at Tay Do university were chosen as the participants. Questionnaire and interview were used as instruments to collect the data. The findings of the study would point out learners’ difficulties consisting of general difficulties (vocabulary, pronunciation, background knowledge and psychological) and difficulties in each part in the TOEIC listening test. Thanks to the results, some solutions would be suggested for students’ improvement. Article visualizations