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Although conventional activated sludge has been demonstrated to be a feasible approach for extracting nitrogenous chemicals and organic pollutants from wastewater, it still has a number of drawbacks. In this research, a pilot-scale biocord-integrated fixed-film activated sludge (Biocord-IFAS) reactor fed with actual domestic wastewater was operated to examine the effect of varying hydraulic retention time (HRT) on the COD and nitrogen removal. The type of material employed in this study is fibrous polypropylene (biocord), which is a major difference. The contribution of the Biocord-IFAS to COD removal efficiency reached 94.2% at HRT of 8 h and gradually decreased to 82.9% when HRT was reduced to 4 h. During the investigation period, a slight decrease in nitrification was found at a shorter HRT. The NH4+-N removal efficiencies at HRTs of 10, 8, 6, and 4 h were 97.8%, 98.7%, 97.1%, and 96.3%, respectively. The average effluent nitrate concentration was 5.3 mg/L with HRTs from 10 to 6 h, but over 30 mg/L with an HRT of 4 h. The SEM analysis results show that microorganisms have formed on the biocord surface. The results of this research have demonstrated the potential application of IFAS reactors in bioremediation procedures employing biocord material with great processing efficiency.

E-cigarettes (e-cigarettes) have been using social media as an informative platform to promote e-cigarettes for their users. The most popular social media in Vietnam were YouTube and Facebook. The information and knowledge could affect e-cigarette user’s belief and the way they make a decision. Despite this, there is a gap in our knowledge of policy maker’s in user’s perceptions about how they feel with promotion on social media platform in Vietnam. This study aimed to describe the promotion of e-cigarettes by providers on some social networks and to describe electronic cigarette users’ feedback about videos/posts of providers on some social networks in Vietnam in 2019. Searches in major electronic databases, including Facebook and YouTube, were conducted using the following search terms: “electronic cigarette,” “electronic vaporizer,” “electronic pod,”. The video/post was selected if they’re from providers and include advertising content on the social media platform during 2019. Of the 104 e-cigarette related videos/posts retrieved, there were 27% on Facebook and 28% on YouTube. The three most common advertising contents were beneft of using e-cigarette, negative health consequences and entertainment effects.

We propose a two-step simulation scheme for the solution of a singular stochastic differential equation with exploding drift. First we estimate the strong order of the Yosida approximation. Then we use a semi-implicit Euler scheme to discretize the approximate solution. Numerical experiments are displayed for the paths of Brownian particles with strong repulsive interaction. We also present two simple simulation schemes for Bessel processes with arbitrary dimension.

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