Vietnam Journal of Science, Technology and Engineering最新文献

{"title":"Treatment of benzene, toluene, and xylene by deep oxidation on CuO catalytic materials synthesised from red mud and rice husk ash","authors":"T. T. Nguyen, P. Nguyen, Thi Thuy Nguyen, Tri Nguyen, K. Huynh","doi":"10.31276/VJSTE.61(2).29-34","DOIUrl":"https://doi.org/10.31276/VJSTE.61(2).29-34","url":null,"abstract":"In this study, CuO-doped material fabricated from rice husk ash and red mud was modified by CeO2 promoter and urea using the impregnation method. The obtained samples were investigated for catalytic degradation of aromatic derivatives (benzene,toluene, and p-xylene - BTX) at a temperature range of 275 to 450oC. This demonstrated that all samples were highly active in the BTX treatment. Several techniques, such as X-ray powder diffraction analysis (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), BET surface areas and pore parameters (N2physisorption), and hydrogen temperature programed reduction (H2-TPR), were applied to analyse properties of obtained materials. The modification of CuO-doped catalytic material by both CeO2 promoter and urea resulted in decreased particle size, increased CuO dispersion, and improved catalytic activity of the material. In relation to this material, the conversions of benzene, toluene, and p-xylene were 66.1%, 96.8%, and 96.8% respectively at 375oC.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"312 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86768539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In vitro and field responses of various active ingredients to Fusarium proliferatumspecies which causes Fusarium root rot disease in Indian mulberry (Morinda officinalis How.) in Thai Nguyen","authors":"D. Nguyen, Nguyen Thi Ngoc Hoa, L. K. Oanh, D. K. Tuyen, N. C. Hieu, D. S. Ha, To Thi Ngan","doi":"10.31276/VJSTE.61(2).47-51","DOIUrl":"https://doi.org/10.31276/VJSTE.61(2).47-51","url":null,"abstract":"Fusarium proliferatum has been identified as the causal pathogen of Fusarium root rot of Ba kich (Morinda officinalis) (FRRBK). No studies are available regarding the effectiveness of chemical treatments on the disease incidence of FRRBK. The efficacy of five active ingredients (metconazole, prochloraz, tebuconazole, kresoxim-methyl, and pyraclostrobin) from two chemical groups (demethylation inhibitors and quinone outside inhibitors) in reducing three isolates (BKVN, BKDT, and BKPL) of F. proliferatum mycelial growth was tested in vitro. The results indicate that only metconazole, prochloraz, and tebuconazole are highly effective in inhibiting the mycelial growth of F. proliferatum. These were selected for investigation of their efficacy with regard to the disease incidence of FRRBK in pot and in field conditions. Prochloraz and metconazole showed the highest efficacy and significantly suppressed the disease incidence of FRRBK in pot and in field conditions.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"112 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87812254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The value of malnutrition-inflammation-atherosclerosis (MIA) syndrome for predicting mortality in patients with end-stage renal disease at Hue Central Hospital","authors":"T. Ngo, Bui Bao Hoang, Tam T Vo","doi":"10.31276/VJSTE.61(2).52-59","DOIUrl":"https://doi.org/10.31276/VJSTE.61(2).52-59","url":null,"abstract":"Background: the role of malnutrition, inflammation, atherosclerosis, and particularly the combination of these three factors were closely related to cardiovascular events, hospitalisation frequency, and death in end-stage renal disease (ESRD) patients. This study examines the relationship between malnutrition-inflammation-atherosclerosis (MIA) syndrome and mortality among these patients during an 18-month period.Subjects and methods: in this prospective observational cohort study, all cause-mortalitywas evaluated during an 18-month follow-up period. A total of 174 patients with ESRD (including 57 non-dialysis patients, 56 peritoneal dialysis patients, and 61 hemodialysis patients) were enrolled. M (malnutrition) was assessed by the seven-point subjective global assessment (SGA), serum albumin. I (inflammation) was assessed by serum hs-CRP, serum IL-6. A (atherosclerosis) was defined asIMT ≥0.9 mm or the presence of plaque in the carotid artery. The patients are classified into four groups by number of components (MIA0, MIA1, MIA2, MIA3). Results: 73.6% of patients had at least one component of MIA syndrome. The proportion of patients with malnutrition, inflammation, and atherosclerosis accounted for 36.8%, 21.3%, and 50.6%, respectively. The proportion of patients with 3, 2, 1 component accounted for 4.0, 27.0, and 42.5%. There was no difference between MIA groups based on age, sex, percentage suffering from dyslipidemia, anemia, or Hb levels. Relative to patients experiencing no elements of MIA syndrome, patients with three components experienced a 13.16 times higher risk of mortality. Only malnutrition was a strong predictor of mortality with HR (95% CI): 5.90 (2.46-14.14).Conclusion: clinical physicians should attend more closely to and provideearly assessments ofMIA syndrome in patients with ESRD. They should care for nutrition conditions and thereby provide early and effective treatments. This can contribute to enhancements in quality of life, and decrease mortalityrates inpatients.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"70 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82038655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Removal and bioaccumulation of copper by the freshwater green alga Scenedesmus sp.","authors":"T. Pham","doi":"10.31276/VJSTE.61(2).65-70","DOIUrl":"https://doi.org/10.31276/VJSTE.61(2).65-70","url":null,"abstract":"Human activities generate vast amounts of wastewater, which contains various toxic metals. Microalgae are able to remove heavy metals from wastewater and accumulate lipid to produce biodiesel. In this study, the abilities to remove copper (Cu) and accumulate lipid of the green algal species Scenedesmus sp. were examined. The microalga Scenedesmus sp. was exposed to Cu concentrations of 0, 0.5, 1, 2, 5, and 10 mg/l under laboratory conditions. The results indicated that Cu inhibited the growth of Scenedesmus sp. at a 96h- EC50 of 7.54 mg/l. Furthermore, the highest removal rate was 89.5%. Lipid accumulation was increased significantly to 23.6% with the addition of Cu at 5 mg/l. The present study indicated that the green alga Scenedesmus sp. possesses the ability to remove Cu from aqueous media and accumulate lipid in its cells. Our results suggested that this species could be applied in wastewater treatment technology and biodiesel production.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77700121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Studying the characteristics of heavy rainfall in the central coastal provinces of Vietnam (Quang Binh case study)","authors":"N. Thang, V. Thang, T. Trong, J. Faucet, Vietnam Hanoi","doi":"10.31276/VJSTE.61(2).71-78","DOIUrl":"https://doi.org/10.31276/VJSTE.61(2).71-78","url":null,"abstract":"This paper explores the maximum amount of rainfall in the Central coastal provinces of Vietnam (Quang Binh case study) for return periods of 5 years, 10 years, 20 years, 50 years, and 100 years, which correspond to frequencies of 20%, 10%, 5%, 2%, and 1%, respectively. The results show that at a frequency of 20%, the maximum intensity of rain during a heavy rain spell can range from 636.6 to 696.0 mm, while the maximum one-day amount received was over 300 mm, which can occur many times in 5 years. At a frequency of 1%, the intensity of rain during a heavy rain spell can range from 1,197.9 to 1,268.3 mm, while the maximum one-day amount ranged from 487.4 to 521.9 mm. However, such values are very rare over the course of 100 years. In addition, in terms of annual rainfall, the spatial distribution of heavy rainfall in coastal areas was significantly smaller than that in mountainous areas. The highest one-day and five-day rainfall have the same pattern of spatial distribution as annual rainfall.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"212 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75916026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Calculating the carbon footprint of rice production in Vietnam and formulating a proposal for mitigation options","authors":"Dao Minh Trang, H. T. Huong, M. Trinh","doi":"10.31276/VJSTE.61(2).84-89","DOIUrl":"https://doi.org/10.31276/VJSTE.61(2).84-89","url":null,"abstract":"This study aims to develop a method for calculating the carbon footprint of rice during its life cycle by combining Life Cycle Assessment (LCA) and the 2006 Guideline of the Intergovernmental Panel on Climate Change (IPCC) for National Greenhouse Gas Inventories (GL 2006) for paddy rice grown in Phu Luong commune, Dong Hung district, Thai Binh province, Vietnam. In the course of the study, a LCA survey that included activities in the upstream processes, the agricultural process, and the post-farm stage was conducted based on interviews with three groups of 30 farmer households that apply the conventional practice of rice production, the system of rice intensification (SRI), or the wide-narrow row method. These cultivation practices are applied for both the winter-spring crop and summer-autumn crop seasons. The emissions were calculated by multiplying the activity data by the default emission factors in GL 2006 or in other relevant studies. The emission factors of methane (CH4) from rice cultivation and nitrous oxide (N2O) from agricultural soil were adjusted using actual measurement results from the Institute of Agricultural Environment (IAE) in 2016. The results of the calculations show that the main sources of the emissions that constitute the carbon footprint of rice include: (i) CH4 emissions from rice cultivation; (ii) electricity generation for irrigation; (iii) diesel combustion for the operation of agricultural machinery, and (iv) fertiliser production. Emissions from other activities were negligible. The carbon footprint of spring rice is 2.69kgCO2e/kg of rice grown using the conventional paddy cultivation method, 2.35 kgCO2e/kg for rice grown using the SRI method, and 2.29 kgCO2e/kg for rice grown using the wide-narrow row method. In summer, the carbon footprint for rice grown using the conventional method is 3.72kgCO2e/kg of rice, 3.56 kgCO2e/kg of rice using SRI, and 3.3kgCO2e/kg of rice using the wide-narrow row method. Three mitigation options are proposed: integrated crop management for rice; alternate wetting and drying; and the substitution of urea fertiliser (CO(NH2)2) with ammonium sulphate ((NH4)2SO4).","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89751109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Clinical and paraclinical characteristics of metabolic syndrome in children with overweight and obesity in Dong Nai province, Vietnam","authors":"H. Thieu","doi":"10.31276/VJSTE.61(2).60-64","DOIUrl":"https://doi.org/10.31276/VJSTE.61(2).60-64","url":null,"abstract":"Background: childhood overweight is increasingly common worldwide as are its consequences, which include increased risk of later cardiovascular disease and diabetes. Although metabolic syndrome (MetS) has been extensively studied in adults, not much is known about the condition in children and adolescents. MetS and its individual components are detectable during childhood, and both commonly persist throughout adolescence and adulthood.Objective: to determine the prevalence of MetS and cut-off values of waist circumference (WC) and body mass index (BMI) for predicting MetS in children with overweight and obesity. Methods: we conducted cross-sectional analysis of 510 children with overweight and obesity aged 10 to 15 years in Bien Hoa city, Dong Nai province (2012-2014). MetS diagnosis was defined according to the 2007 International Diabetes Federation definition. Results: a relationship existed between BMI and dyslipidaemia (p<0.05). Among all participants, 31.37% met the criteria for MetS (female>male, p>0.05). The most common manifestation of MetS in this study was WC-blood pressure-triglyceride (41.15%). The cut-off anthropometry values for predicting MetS were as follows: BMI of 25.00 in boys and 24.50 in girls, and WC of 82 cm in boys and 80 cm in girls. Conclusions: the prevalence of MetS was 31.37% among children with overweight and obesity. The cut-off values of WC and BMI in this study could be the optimal threshold for predicting MetS in such children aged 10 to 15 years.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75606392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Attempting near-infrared transillumination imaging with simple instrumentation for studying dental lesions","authors":"Thi Hai Mien Pham, Phu Duong Le, Thien Ta","doi":"10.31276/VJSTE.61(2).42-46","DOIUrl":"https://doi.org/10.31276/VJSTE.61(2).42-46","url":null,"abstract":"During the past decades, near-infrared (NIR) methods have been applied to many aspects of life, particularly in dentistry. X-ray methods involve reliable techniques that dentists use to evaluate tooth structure lesions. However, X-ray methods still have some limitations, such as affecting patient health and dentists. In addition, early demineralised enamel is barely detected by X-ray methods. Many studies have demonstrated the usefulness of NIR light for observing tooth structure due to the differences of the optical properties between sound and demineralised tooth tissues under NIR wavelengths. Early demineralisation located under the enamel layer can be observed by NIR imaging (780-1,300 nm). The areas suspected to be demineralised enamel are distinct from the stain and pigmentation because stain and pigmentation do not appear in NIR images. The demineralised areas are substantially darker than the surrounding sound tissues under NIR light. In this study, two optical systems with transillumination and scattering techniques using NIR light (940 nm) were built for capturing occlusal and approximal images of teeth. The systems fulfill some requirements, such as simple setup, safety, and affordable price for the purpose of the replacement of imported equipment.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87180150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The protoplanetary disc HD 163296 as observed by ALMA","authors":"P. Diep, D. Hoai, N. B. Ngoc, P. T. Nhung, N. T. Phuong, T. T. Thai, P. Tuan-Anh","doi":"10.31276/VJSTE.61(2).03-16","DOIUrl":"https://doi.org/10.31276/VJSTE.61(2).03-16","url":null,"abstract":"HD 163296 is one of the few protoplanetary discs displaying rings in the dust component. The present work uses ALMA observations of the 0.9 mmcontinuum emission, which have significantly better spatial resolution (~8 au) than previously available, to provide new insight into the morphology of the dust disc and its double ring structure. The disc is shown to be thin, and its position angle and inclination with respect to the sky plane are accurately measured as are the locations and shapes that characterise the observed ring-gap structure. Significant modulation of the intensity of the outer ring emission is revealed and discussed. In addition, earlier ALMA observations of the emission of three molecular lines, CO(2-1), C18O(2-1), and DCO+(3-2) with a resolution of ~70 au are used to demonstrate the Keplerian motion of the gas, which is found to be consistent with a central mass of 2.3 solar masses. An upper limit of ~9% of the rotation velocity is placed on the in-fall velocity. The beam size is shown to give the dominant contribution to the line widths, accounting for both their absolute values and their dependence on the distance to the central star.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77761853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The characteristics of seismic activity in the ladder zone of Da river hydro-electric plants","authors":"D. Cao, Van Dung Le, A. Thai, Thanh Hai Dang, Dinh Trieu Cao","doi":"10.31276/VJSTE.61(1).82-91","DOIUrl":"https://doi.org/10.31276/VJSTE.61(1).82-91","url":null,"abstract":"In this paper, the authors describe a study examining the characteristics of seismic activity in the ladder zone of Da river hydro-electric plants. The study results show that:- The occurrence of natural earthquakes in the ladder zone of Da river hydro-electric plants is the strongest in Vietnamese territory. An earthquake magnitude of M=6.7 has been observed in the Tuan Giao and Lai Chau areas, with a b coefficient value (Gutenberg-Richter law) of 0.935.- Natural earthquakes with magnitudes in the range of 6.0-6.9 seem to occur in 13 seismic sources, these being: Muong Te, Nam Nhe, Muong Nhe, Lai Chau - Dien Bien, Son La, Tuan Giao, Phong Tho, Muong La - Bac Yen, Song Da (Da River), Nam Tong, Mu Cang Chai, Lao Cai - Ninh Binh (Phan Sipan), and Mai Chau. Of these, an apparent risk of strong earthquakes, with a magnitude of M=6.9, appears in Muong Te, Lai Chau - Dien Bien, Tuan Giao, Yen Chau, and Mai Chau areas.- Triggered earthquakes with a magnitude M>4.0 have occurred in the region of the Hoa Binh and Son La hydro-electric plant reservoirs, which have a maximum depth of over 100 meters, and a geological structure comprising mainly limestone. - No likelihood of triggered earthquakes in the region of the Hoa Binh hydro-electric plant reservoir; however, in the Son La hydro-electric reservoir region, a triggered earthquake is expected in the future with a strong magnitude of M=4.3, or possibly even M=5.0.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"232 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82202687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}