HYDROTHERMAL SYNTHESIS OF NANO BILAYERED V2O5 AND ELECTROCHEMICAL BEHAVIOR IN NON–AQUEOUS ELECTROLYTES LiPF6 AND NaClO4

This work aimed to prepare bilayered V2O5 by hydrothermal route from vanadium (III) chloride (VCl3). According to XRD results, bilayered V2O­5 showed a large interlayer spacing around 11.3 Å. The electrochemical properties of bilayered V2O5 were carried out by cyclic voltammetry and charge–discharge testing in non–aqueous electrolytes LiPF6 and NaClO4. The curves charge–discharge showed that mechanism of insertion/extraction of Li+ ions and Na+ ions were occurred on a solution solid without the phase transition. Moreover, specific capacity for lithium and sodium intercalation of bilayered V2O5 were found out 250 mAh/g and 200 mAh/g, respectively. The kinetic of lithium’s and sodium’s insertion was evaluated by the electrochemical impedance spectroscopy (EIS). The EIS results exhibited a stabilization of charge transfer in both case and a slow kinetic of sodium’s diffusion compared to lithium’s case due to the large ionic radius of sodium

Efficient Integration of Multi-Order Dynamics and Internal Dynamics in Stock Movement Prediction

Advances in deep neural network (DNN) architectures have enabled new prediction techniques for stock market data. Unlike other multivariate time-series data, stock markets show two unique characteristics: (i) \emph{multi-order dynamics}, as stock prices are affected by strong non-pairwise correlations (e.g., within the same industry); and (ii) \emph{internal dynamics}, as each individual stock shows some particular behaviour. Recent DNN-based methods capture multi-order dynamics using hypergraphs, but rely on the Fourier basis in the convolution, which is both inefficient and ineffective. In addition, they largely ignore internal dynamics by adopting the same model for each stock, which implies a severe information loss. In this paper, we propose a framework for stock movement prediction to overcome the above issues. Specifically, the framework includes temporal generative filters that implement a memory-based mechanism onto an LSTM network in an attempt to learn individual patterns per stock. Moreover, we employ hypergraph attentions to capture the non-pairwise correlations. Here, using the wavelet basis instead of the Fourier basis, enables us to simplify the message passing and focus on the localized convolution. Experiments with US market data over six years show that our framework outperforms state-of-the-art methods in terms of profit and stability. Our source code and data are available at \url{https://github.com/thanhtrunghuynh93/estimate}.Comment: Technical report for accepted paper at WSDM 202

Pollution and Risk Level Assessment of Pollutants in Surface Water Bodies

The study was carried out to assess the pollution, impact, and risk level to the surface water environment of pollutants in the water bodies of Soc Trang province, Vietnam. The parameters for evaluating surface water quality and risks included temperature, pH, TSS, DO, BOD, COD, NH4+-N, NO2--N, NO3--N, PO43--P, Cl-, Fet, and coliform. Surface water samples were collected at 35 locations with a frequency of six times (February, April, June, August, October, and December) in 2022. The water quality index (WQI), impact and risk level (risk quotient or RQ, RQ-F), correlation analysis, and principal component analysis (PCA) were utilized in the study. The results show that the surface water has been seriously polluted due to organic matter, nutrients, microorganisms, iron, and salinity. The values of WQI in the dry and rainy seasons fluctuated between bad and very good, indicating that surface water quality is suitable for water transport and other purposes with higher quality requirements. TSS, COD, Fet and coliform have a high impact and risk for the environment in this study area. There were no environmental impacts and risks to NO3--N. Locations with many high-risk pollutants were mainly distributed in residential and coastal areas. The significant negative correlation between the WQI and RQ indicated that the lower the WQI, the higher the environmental risk. The PCA results show that at least six polluting sources affected water quality and caused environmental risks. The results of this study contribute essential and valuable information for improving water quality in the study area through the assessment of environmental impacts and risks. Doi: 10.28991/CEJ-2023-09-08-03 Full Text: PD

Optimization of Main Factors Affecting Construction Waste by the Supply Chain Management

A survey report of the Vietnam Urban Environment and Industrial Zone Association reveals that every day in 2009, about 1,000 tons of construction waste were generated in Hanoi and 2,000 tons Ho Chi Minh City in Vietnam. It is forecasted that the coming years would see a vigorously growing amount of construction waste as a result of the plan to dismantle and renovate old apartment buildings in major cities. So, in this research we developed a supply chain management strategy for the waste controlling in the construction industry. While the bulky volume of construction wastes poses a great environmental threat to urban areas, response to it remains meager. Hence, this paper presents four primary factors affecting the management of construction wastes in Vietnam using fuzzy logic

Efficient Image Watermarking Using Filtered DWT-Blocks for Quantization of Significant Differences

In the paper, a robust blind watermarking method is introduced for gray-scale images based on wavelet tree quantization with an adaptive threshold in the extraction. Every block of 2×2 coefficients of High-Low subbands of the Wavelet tranform are grouped in a block through the parent-child relationship of the wavelet tree. Every scrambled binary watermark bit is embedded into each block based on the difference value of two largest coefficients. The watermark is recovered by comparing the difference values in each block to an adaptive threshold. The accuracy of an extracted watermark depends on the threshold which is determined by minimizing the sum of weighted within-class variance. The performance of the proposed watermarking method is represented through experimental results under various types of attack such as, Histogram Equalization, Cropping, Low-pass Filtering, Gaussian noise, Salt & Pepper noise and JPEG compression. In additions, the proposed method is also compared to recent methods in the extraction performance

Study on anticorrosion properties of epoxy primers on steel.

Epoxy resin DER 671X75 was reinforced by nanoclay cloisite 30B with content of 2% and primer coatings based on epoxy resin DER 671X75 were formed with pigments, fillers. Epoxy coating  films were exposed by electrochemical method in NaCl 3.5 % solution in 28 days and salt spray accelerated tester in 330 hrs. The results show that nanoclay cloisite 30B are improved anticorrosion properties of primer coatings based on epoxy resin DER671X75. Keywords. Epoxy primer coating, nanoclay cloisite 30B, epoxy resin DER 671X75, electrochemical, anticorrosion properties steel

Phlogacanthus cornutus: chemical profiles and antioxidant effects

Phlogacanthus cornutus is a rare species and the chemical profiles and the bioactivities of this plant are unknown. In present study, the chemical components of the acetone extract as well as the antioxidant activity of acetone extract and its fractions such as n-hexane, chloroform and ethyl acetate of P. cornutus were firstly reported. A total of 33 constituents were identify in the acetone extract of this plant using Gas Chromatography/Mass Spectrometry assay, in which trans-cinnamic acid (21.26%), neophytadiene (6.36%), linolenic acid (5.86%), dihydroagathic acid (5.71%), n-hexadecanoic acid (5.53%), phytol (4.14%) and cis-cinnamic acid (3.23%) were the major compounds. The acetone extract and its fractions such as n-hexane, chloroform and ethyl acetate of P. cornutus showed DPPH radical scavenging activity with IC50 value of 234.31, 185.95, 758.65 and 458.52 µg/mL respectively

Age-time-specific transmission of hand-foot-and-mouth disease enterovirus serotypes in Vietnam: a catalytic model with maternal immunity

Hand, foot and mouth disease (HFMD) is highly prevalent in the Asia Pacific region, particularly in Vietnam. To develop effective interventions and efficient vaccination programs, we inferred the age-time-specific transmission patterns of HFMD serotypes enterovirus A71 (EV-A71), coxsackievirus A6 (CV-A6), coxsackievirus A10 (CV-A10), coxsackievirus A16 (CV-A16) in Ho Chi Minh City, Vietnam from a case data collected during 2013–2018 and a serological survey data collected in 2015 and 2017. We proposed a catalytic model framework with good adaptability to incorporate maternal immunity using various mathematical functions. Our results indicate the high-level transmission of CV-A6 and CV-A10 which is not obvious in the case data, due to the variation of disease severity across serotypes. Our results provide statistical evidence supporting the strong association between severe illness and CV-A6 and EV-A71 infections. The HFMD dynamic pattern presents a cyclical pattern with large outbreaks followed by a decline in subsequent years. Additionally, we identify the age group with highest risk of infection as 1-2 years and emphasise the risk of future outbreaks as over 50% of children aged 6-7 years were estimated to be susceptible to CV-A16 and EV-A71. Our study highlights the importance of multivalent vaccines and active surveillance for different serotypes, supports early vaccination prior to 1 year old, and points out the potential utility for vaccinating children older than 5 years old in Vietnam

LAYERED O3-NaFe0.5Co0.5O2 AS HIGH CAPACITY AND LOW- COST MATERIAL FOR SODIUM ION BATTERIES

O3-NaFe0.5Co0.5O2 layered cathode material was synthesized by solid state reaction at 900 oC followed by a quenching step in argon atmosphere. The chemical composition and morphology of synthesized material were analyzed by Atomic Absorption Spectroscopy (AAS) and Scanning Electron Microscopy (SEM). The electrochemical properties were evaluated by Cyclic Voltammetry (CV) and charge-discharge cycling. The material NaFe0.5Co0.5O2 shows the sloped discharge curves with high flat voltage plateau and excellent cycling stability. The reversible capacity of about 120 mAh/g at rate C/10 and good capacity retention after 100 cycles were obtained