Pub Date : 2022-07-15DOI: 10.51316/jst.159.etsd.2022.32.3.7
T. Ngoc, L. Bac
In this study, the effects of Fe dopant on the structural, optical, and electrical properties of NiTiO3 materials prepared by sol-gel method were investigated. The prepared powders were investigated through X-ray diffraction, Raman scattering, scanning electron microscope, UV-visible absorption, vibrating sample magnetometer, electrical measurement to explore the structural, ferromagnetic, and electrical properties. The single-phase Ni1-xFexTiO3 (x = 0, 0.05 and 0.10) materials were obtained. Doping of Fe into NiTiO3 lead to the decreasing of lattice parameter and increased the particle size compared to the undoped sample. Ferroelectric and ferromagnetic properties of all Fe-doped NiTiO3 ceramics have been investigated at room temperature. The ferromagnetic hysteresis loop of the Fe-doped NiTiO3 sample at room temperature is due to the formation of oxygen vacancies and their associated exchange interaction. Ferroelectric properties of Fe doped samples were decreased with the increase of Fe concentration. This can be due to the Fe dopant into NiTiO3 material. The Fe dopant caused to increase the conductivity of NiTiO3 sample which resulted in a decrease in ferroelectric parameters.
{"title":"Effects of Fe Dopant on Structural, Optical and Electrical Properties of NiTiO3 Materials","authors":"T. Ngoc, L. Bac","doi":"10.51316/jst.159.etsd.2022.32.3.7","DOIUrl":"https://doi.org/10.51316/jst.159.etsd.2022.32.3.7","url":null,"abstract":"In this study, the effects of Fe dopant on the structural, optical, and electrical properties of NiTiO3 materials prepared by sol-gel method were investigated. The prepared powders were investigated through X-ray diffraction, Raman scattering, scanning electron microscope, UV-visible absorption, vibrating sample magnetometer, electrical measurement to explore the structural, ferromagnetic, and electrical properties. The single-phase Ni1-xFexTiO3 (x = 0, 0.05 and 0.10) materials were obtained. Doping of Fe into NiTiO3 lead to the decreasing of lattice parameter and increased the particle size compared to the undoped sample. Ferroelectric and ferromagnetic properties of all Fe-doped NiTiO3 ceramics have been investigated at room temperature. The ferromagnetic hysteresis loop of the Fe-doped NiTiO3 sample at room temperature is due to the formation of oxygen vacancies and their associated exchange interaction. Ferroelectric properties of Fe doped samples were decreased with the increase of Fe concentration. This can be due to the Fe dopant into NiTiO3 material. The Fe dopant caused to increase the conductivity of NiTiO3 sample which resulted in a decrease in ferroelectric parameters.","PeriodicalId":17641,"journal":{"name":"JST: Engineering and Technology for Sustainable Development","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74768632","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}
Pub Date : 2022-07-15DOI: 10.51316/jst.159.etsd.2022.32.3.4
Chu Diệu Hương, Nguyen Thi Tuyet Trinh
Fabric treated by fragrance was one of textile applications. The evaluation of fragrance durability of fabric treated by the fragrance was always the subject of many researches, though quantitatively determining fragrance intensity was difficult and there will not always be agreement on odor characteristics by different testers. In this paper, we built a simple and quantitative method to evaluate the fragrance intensity, which could be considered as the remained oil quantity on fabric treated by microcapsule loaded with star anise essential oil. The evaluation was based on the combination of the expert method and diluted solution method. This method was used to evaluate the influence of the knitted fabric’s keeping conditions on fragrance duration of the fabric. Two groups of single jersey fabric have been prepared: one was knitted from the Ne 40/1 Chief Value Cotton (CVC) yarn (60% cotton and 40% polyester). The second group was also single jersey fabric knitted from the Ne 46/1 100% cotton. The knitted fabrics were treated with microcapsules containing star anise essential oil and then have been kept in ambient conditions (temperature was about 25 oC ±2, relative humidity was 75% ±2) and in the cold dried condition (temperature was about 2 oC, relative humidity was 20%). The results showed that the developing method in the research can be used to effectively quantitatively evaluate the fragrance intensity of fabric treated by fragrance. The fabrics treated by microcapsules containing star anise oil essential remained their fragrance longer than 7 days in the cool dried condition while which ones in the ambient condition finished their fragrance after 5 days.
{"title":"Quantitative Fragrance Durability Evaluation Depending on Keeping Condition of Knitted Fabric Treated by Microcapsules Containing Star Anise Essential Oil","authors":"Chu Diệu Hương, Nguyen Thi Tuyet Trinh","doi":"10.51316/jst.159.etsd.2022.32.3.4","DOIUrl":"https://doi.org/10.51316/jst.159.etsd.2022.32.3.4","url":null,"abstract":"Fabric treated by fragrance was one of textile applications. The evaluation of fragrance durability of fabric treated by the fragrance was always the subject of many researches, though quantitatively determining fragrance intensity was difficult and there will not always be agreement on odor characteristics by different testers. In this paper, we built a simple and quantitative method to evaluate the fragrance intensity, which could be considered as the remained oil quantity on fabric treated by microcapsule loaded with star anise essential oil. The evaluation was based on the combination of the expert method and diluted solution method. This method was used to evaluate the influence of the knitted fabric’s keeping conditions on fragrance duration of the fabric. Two groups of single jersey fabric have been prepared: one was knitted from the Ne 40/1 Chief Value Cotton (CVC) yarn (60% cotton and 40% polyester). The second group was also single jersey fabric knitted from the Ne 46/1 100% cotton. The knitted fabrics were treated with microcapsules containing star anise essential oil and then have been kept in ambient conditions (temperature was about 25 oC ±2, relative humidity was 75% ±2) and in the cold dried condition (temperature was about 2 oC, relative humidity was 20%). The results showed that the developing method in the research can be used to effectively quantitatively evaluate the fragrance intensity of fabric treated by fragrance. The fabrics treated by microcapsules containing star anise oil essential remained their fragrance longer than 7 days in the cool dried condition while which ones in the ambient condition finished their fragrance after 5 days.","PeriodicalId":17641,"journal":{"name":"JST: Engineering and Technology for Sustainable Development","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73148524","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}
Pub Date : 2022-04-15DOI: 10.51316/jst.157.etsd.2022.32.2.5
Van Tien Nguyen, Tran Dang Quoc
Today, the prices of fossil fuels such as gasoline and diesel are skyrocketing, oil depletion and air pollution are major challenges for us and the auto industry in particular. Natural gas has known as a potential alternative fuel for internal combustion engines because of its advantages such as the octane number, which is higher than that of gasoline, the low heat value which is higher in comparison with gasoline and diesel and the safety in use. This paper presents a study on the influence of squish area on engine performance of single cylinder natural gas converted engine. The obtained results indicated that the increase of compression ratio only augmented the risk of knocking for single cylinder natural gas converted engine. Conversely, the modification of bowl-in-piston is directly varied squish area, thus the turbulent kinetic energy of the gas flows at the end of the compression stroke increased in comparison with the flat head piston of the original engine.
{"title":"A Study on the Effect of Squish Area on Engine Performance of Single Cylinder Natural Gas Converted Engine","authors":"Van Tien Nguyen, Tran Dang Quoc","doi":"10.51316/jst.157.etsd.2022.32.2.5","DOIUrl":"https://doi.org/10.51316/jst.157.etsd.2022.32.2.5","url":null,"abstract":"Today, the prices of fossil fuels such as gasoline and diesel are skyrocketing, oil depletion and air pollution are major challenges for us and the auto industry in particular. Natural gas has known as a potential alternative fuel for internal combustion engines because of its advantages such as the octane number, which is higher than that of gasoline, the low heat value which is higher in comparison with gasoline and diesel and the safety in use. This paper presents a study on the influence of squish area on engine performance of single cylinder natural gas converted engine. The obtained results indicated that the increase of compression ratio only augmented the risk of knocking for single cylinder natural gas converted engine. Conversely, the modification of bowl-in-piston is directly varied squish area, thus the turbulent kinetic energy of the gas flows at the end of the compression stroke increased in comparison with the flat head piston of the original engine.","PeriodicalId":17641,"journal":{"name":"JST: Engineering and Technology for Sustainable Development","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83113056","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}
Pub Date : 2022-04-15DOI: 10.51316/jst.157.etsd.2022.32.2.2
N. T. Thuong, P. T. Nghia, S. Kawahara
Removal of protein from natural rubber was carried out via deproteinization of natural rubber in the latex stage. Then, its effect on the molecular structure and properties of natural rubber was investigated. Urea, SDS, and acetone were used as denaturing agent, a surfactant, and a polar solvent in the deproteinization, respectively. Various deproteinized natural rubbers were obtained after one, two, and three times of centrifugation with and without acetone, namely DPNR1, DPNR2, DPNR3, DPNR1-A, DPNR2-A, and DPNR3-A. It was found that the total protein content significantly decreased as increasing the number of centrifugations; however, the total fatty acid contents showed a slight decrease. Structural characteristics analyzed by nuclear magnetic resonance spectroscopy indicated no changes in the chemical structure of natural rubber after deproteinization. However, the removal of proteins significantly enhanced the resolution of the NMR signals. Gel content and tensile properties of natural rubber showed a decrease in the removal of proteins, which was associated with the decrease in the number of the inherent branching points formed in natural rubber.
{"title":"Removal of Proteins and Its Effect on Molecular Structure and Properties of Natural Rubber","authors":"N. T. Thuong, P. T. Nghia, S. Kawahara","doi":"10.51316/jst.157.etsd.2022.32.2.2","DOIUrl":"https://doi.org/10.51316/jst.157.etsd.2022.32.2.2","url":null,"abstract":"Removal of protein from natural rubber was carried out via deproteinization of natural rubber in the latex stage. Then, its effect on the molecular structure and properties of natural rubber was investigated. Urea, SDS, and acetone were used as denaturing agent, a surfactant, and a polar solvent in the deproteinization, respectively. Various deproteinized natural rubbers were obtained after one, two, and three times of centrifugation with and without acetone, namely DPNR1, DPNR2, DPNR3, DPNR1-A, DPNR2-A, and DPNR3-A. It was found that the total protein content significantly decreased as increasing the number of centrifugations; however, the total fatty acid contents showed a slight decrease. Structural characteristics analyzed by nuclear magnetic resonance spectroscopy indicated no changes in the chemical structure of natural rubber after deproteinization. However, the removal of proteins significantly enhanced the resolution of the NMR signals. Gel content and tensile properties of natural rubber showed a decrease in the removal of proteins, which was associated with the decrease in the number of the inherent branching points formed in natural rubber.","PeriodicalId":17641,"journal":{"name":"JST: Engineering and Technology for Sustainable Development","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84333414","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}
Pub Date : 2022-04-15DOI: 10.51316/jst.157.etsd.2022.32.2.9
N. Kien, D. H. Phuc, Lai Nang Vu, Vu Hai Thuong
Optimal control methods are increasingly used in automatic control systems, especially in automotive suspension system. However, the optimal control algorithm only achieves the highest efficiency in suspension control system when the required number of sensors is sufficient, corresponding to the number of states in the system. The arrangement of sufficient number of sensors depends on the capacity, economic conditions and responsiveness of the sensor. The Kalman observer is designed to reliably estimate the required parameters in the control where the number of sensors is limited. The article focuses on analyzing the theory of building a quarter-car model, developing and determining the optimal control matrix, the Kalman observer design method. The findings of the article reveal the effectiveness of automotive body vibration suppression and the required force for control corresponding to LQG control and LQR control, under the influence of square pulse road surface, when using two similar sensors are installed on the sprung and unsprung, thereby providing a choice of sensor type and the location on the semi-active ¼ suspension.
{"title":"Control of Semi-Active Suspension System Using Kalman Observer","authors":"N. Kien, D. H. Phuc, Lai Nang Vu, Vu Hai Thuong","doi":"10.51316/jst.157.etsd.2022.32.2.9","DOIUrl":"https://doi.org/10.51316/jst.157.etsd.2022.32.2.9","url":null,"abstract":"Optimal control methods are increasingly used in automatic control systems, especially in automotive suspension system. However, the optimal control algorithm only achieves the highest efficiency in suspension control system when the required number of sensors is sufficient, corresponding to the number of states in the system. The arrangement of sufficient number of sensors depends on the capacity, economic conditions and responsiveness of the sensor. The Kalman observer is designed to reliably estimate the required parameters in the control where the number of sensors is limited. The article focuses on analyzing the theory of building a quarter-car model, developing and determining the optimal control matrix, the Kalman observer design method. The findings of the article reveal the effectiveness of automotive body vibration suppression and the required force for control corresponding to LQG control and LQR control, under the influence of square pulse road surface, when using two similar sensors are installed on the sprung and unsprung, thereby providing a choice of sensor type and the location on the semi-active ¼ suspension.","PeriodicalId":17641,"journal":{"name":"JST: Engineering and Technology for Sustainable Development","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82729880","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}
Pub Date : 2022-04-15DOI: 10.51316/jst.157.etsd.2022.32.2.8
Xuan-Dung Nguyen, Trung-Kien Vo, M. Ha
Traditional control methods designed for the trajectory tracking problem of under-actuated vehicles often aim to directly stabilize the tracking-error system of differential equations to the origin. This often results in complex control algorithms. This paper introduces a simplified control method for the trajectory tracking problem of an under-actuated Unmanned Surface Vehicle (USV). The proposed method consists of a guidance law for intermediate variables, which are the pseudo-yaw angle and the pseudo-surge velocity, and a Proportional-Integral (PI) controller. The control term for surge velocity is designed to be bounded, which reduces undesired instability. A model is built based on linear dynamics equations and parameters of an USV. The proposed tracking method is applied to the model to track different trajectories in simulations. The simulation results show that the proposed method effectively tracks different trajectories under various initial conditions. The control term for surge velocity remains stable despite the relatively large initial tracking-error condition.
{"title":"Simplified Trajectory-Tracking Method for an Under-Actuated USV","authors":"Xuan-Dung Nguyen, Trung-Kien Vo, M. Ha","doi":"10.51316/jst.157.etsd.2022.32.2.8","DOIUrl":"https://doi.org/10.51316/jst.157.etsd.2022.32.2.8","url":null,"abstract":"Traditional control methods designed for the trajectory tracking problem of under-actuated vehicles often aim to directly stabilize the tracking-error system of differential equations to the origin. This often results in complex control algorithms. This paper introduces a simplified control method for the trajectory tracking problem of an under-actuated Unmanned Surface Vehicle (USV). The proposed method consists of a guidance law for intermediate variables, which are the pseudo-yaw angle and the pseudo-surge velocity, and a Proportional-Integral (PI) controller. The control term for surge velocity is designed to be bounded, which reduces undesired instability. A model is built based on linear dynamics equations and parameters of an USV. The proposed tracking method is applied to the model to track different trajectories in simulations. The simulation results show that the proposed method effectively tracks different trajectories under various initial conditions. The control term for surge velocity remains stable despite the relatively large initial tracking-error condition.","PeriodicalId":17641,"journal":{"name":"JST: Engineering and Technology for Sustainable Development","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76964972","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}
Pub Date : 2022-04-15DOI: 10.51316/jst.157.etsd.2022.32.2.4
LE Van-Minh, C. Dinh, Q. Pham, TA Duc-Huy, V. Quang-sang, H. Luu, The-Mich Nguyen, A. Nguyen
The combustion chamber clearly plays an critical role in generating thrust force so the aircraft can move forward. A scramjet (supersonic combustion ramjet) is a variant of a ramjet airbreathing jet engine in which combustion takes place in supersonic airflow. Researchers are constantly working to improve the efficiency of ultrasonic combustion furnaces by various methods such as: optimize fuel injectors, optimize combustion chamber geometry design, create hole cavity. In this research, the characteristic of supersonic airflow were investigated, and a comparison between the standard chamber and advanced chamber was made to determine the effects of a circular hole (cavity) on pressure and velocity of the fuel mixture through the scramjet. Two dimensional Reynolds-Averaged Navier-Stokes governing(RANS) equations with k− turbulence model and finite rate/eddy dissipation chemistry model have been considered for modelling chemical reacting flows. From the comparison of numerical results, it is found that the development of recirculation regions and additional shock waves from the edge of cavity flame holder is increased and achieved stabilized combustion. From this research analysis, the performance of the scramjet engine with cavity is significantly improved as compared to the design without cavity
显然，燃烧室在产生推力方面起着至关重要的作用，这样飞机才能向前移动。超燃冲压发动机(超音速燃烧冲压发动机)是冲压喷气发动机的一种改进型，其燃烧在超音速气流中进行。研究人员通过优化喷油器、优化燃烧室几何设计、创建空腔等各种方法不断提高超声燃烧炉的效率。通过对超声速气流特性的研究，对标准腔室和先进腔室进行了对比，确定了圆孔(腔)对燃料混合物通过超燃冲压发动机压力和速度的影响。考虑了二维reynolds - average Navier-Stokes控制(RANS)方程和k−湍流模型和有限速率/涡流耗散化学模型来模拟化学反应流动。通过数值计算结果的比较，发现该方法增加了再循环区域的发展，增加了来自腔焰器边缘的附加激波，实现了稳定燃烧。研究结果表明，与不含空腔的超燃冲压发动机相比，带空腔的超燃冲压发动机的性能得到了显著提高
{"title":"Appraisal Burning Characteristic and Analysis Effect of Cavity in Scramjet Combustion Chamber","authors":"LE Van-Minh, C. Dinh, Q. Pham, TA Duc-Huy, V. Quang-sang, H. Luu, The-Mich Nguyen, A. Nguyen","doi":"10.51316/jst.157.etsd.2022.32.2.4","DOIUrl":"https://doi.org/10.51316/jst.157.etsd.2022.32.2.4","url":null,"abstract":"The combustion chamber clearly plays an critical role in generating thrust force so the aircraft can move forward. A scramjet (supersonic combustion ramjet) is a variant of a ramjet airbreathing jet engine in which combustion takes place in supersonic airflow. Researchers are constantly working to improve the efficiency of ultrasonic combustion furnaces by various methods such as: optimize fuel injectors, optimize combustion chamber geometry design, create hole cavity. In this research, the characteristic of supersonic airflow were investigated, and a comparison between the standard chamber and advanced chamber was made to determine the effects of a circular hole (cavity) on pressure and velocity of the fuel mixture through the scramjet. Two dimensional Reynolds-Averaged Navier-Stokes governing(RANS) equations with k− turbulence model and finite rate/eddy dissipation chemistry model have been considered for modelling chemical reacting flows. From the comparison of numerical results, it is found that the development of recirculation regions and additional shock waves from the edge of cavity flame holder is increased and achieved stabilized combustion. From this research analysis, the performance of the scramjet engine with cavity is significantly improved as compared to the design without cavity","PeriodicalId":17641,"journal":{"name":"JST: Engineering and Technology for Sustainable Development","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89061761","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}
Pub Date : 2022-04-15DOI: 10.51316/jst.157.etsd.2022.32.2.1
L. Thuy, T. Huong, Le Huyen Tram, N. Dang
Natural products and their derivatives represent more than 50% of all the drugs in modern therapeutics. Flavonoids and lignans are a large group of naturally occurring and play a variety of biological activities in plants. Schisandraceae family includes 2 genera, Schisandra and Kadsura with about 39 species of plants. The Kadsura coccinea, belonging to Schisandraceae family, is mainly distributed in the tropical and subtropical regions of South and Southeast Asia. The aim of this study is the isolation and structural elucidation of compounds isolated from the leaves of Kadsura coccinea. For this purpose, five known flavonoid compounds, (+) gallocatechin (1), catechin (2), (-) epicatechin (3), phloretin-2-O-glucoside (4), phloretin-4-O-glucoside (5) together with 2-hydroxy-5-methoxyphenyl-O-β-D-glucopyranoside (6) and icariside E3 (7) were isolated. Their structures are elucidated by NMR spectroscopic analysis as well as compared with the literature. Especially, compound 6 is the first isolated from this plant.
天然产物及其衍生物占现代治疗中所有药物的50%以上。类黄酮和木脂素是植物中大量天然存在的具有多种生物活性的物质。五味子科包括五味子和五味子2属，植物约39种。五味子属五味子科，主要分布于南亚和东南亚的热带和亚热带地区。本研究的目的是分离和结构解析从牛蒡叶中分离的化合物。为此，我们分离了五种已知的类黄酮化合物，(+)没食子儿茶素(1)、儿茶素(2)、(-)表儿茶素(3)、邻酚a -2- o -葡萄糖苷(4)、邻酚a -4- o -葡萄糖苷(5)以及2-羟基-5-甲氧基苯基- o -β- d -葡萄糖苷(6)和icariside E3(7)。通过核磁共振波谱分析并与文献比较，对其结构进行了鉴定。其中化合物6为首次从该植物中分离得到。
{"title":"\"Structural Elucidation of Some Phenolic Compounds from the Leaves of Kadsura Coccinea in Vietnam\"","authors":"L. Thuy, T. Huong, Le Huyen Tram, N. Dang","doi":"10.51316/jst.157.etsd.2022.32.2.1","DOIUrl":"https://doi.org/10.51316/jst.157.etsd.2022.32.2.1","url":null,"abstract":"Natural products and their derivatives represent more than 50% of all the drugs in modern therapeutics. Flavonoids and lignans are a large group of naturally occurring and play a variety of biological activities in plants. Schisandraceae family includes 2 genera, Schisandra and Kadsura with about 39 species of plants. The Kadsura coccinea, belonging to Schisandraceae family, is mainly distributed in the tropical and subtropical regions of South and Southeast Asia. The aim of this study is the isolation and structural elucidation of compounds isolated from the leaves of Kadsura coccinea. For this purpose, five known flavonoid compounds, (+) gallocatechin (1), catechin (2), (-) epicatechin (3), phloretin-2-O-glucoside (4), phloretin-4-O-glucoside (5) together with 2-hydroxy-5-methoxyphenyl-O-β-D-glucopyranoside (6) and icariside E3 (7) were isolated. Their structures are elucidated by NMR spectroscopic analysis as well as compared with the literature. Especially, compound 6 is the first isolated from this plant.","PeriodicalId":17641,"journal":{"name":"JST: Engineering and Technology for Sustainable Development","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80953326","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}
Pub Date : 2022-04-15DOI: 10.51316/jst.157.etsd.2022.32.2.3
N. A. Vũ, N. H. Long, N. T. Thuong
Organic additives, i.e., fatty acid amide compounds, are typically used to reduce the viscosity of asphalt mixture at high-temperatures working operation. Present work focuses on preparing fatty acid amide from waste cooking oil and its characterization as an additive for bitumen. The role of synthesized fatty acid amide as an additive for bitumen was tested on the bitumen 60/70 penetration grade sample. The fatty acid amide was synthesized and characterized by FT-IR and NMR spectroscopy. It showed that the fatty acid amide was successfully prepared from the waste cooking oil due to the presence of the characteristic functional groups. The binders made from fatty acid amide and bitumen with different content of fatty acid amide were prepared and tested. It demonstrated that the kinetic viscosity of the binder reduced by 23 % at 0.7 wt% additive concentration at 140 ºC . Moreover, the penetration and softening point of the binder was also improved, which enhance the binder's physical properties when used at target temperatures.
{"title":"Synthesis of Fatty Acid Amide from Waste Cooking Oil as an Additive for Asphalt Binder","authors":"N. A. Vũ, N. H. Long, N. T. Thuong","doi":"10.51316/jst.157.etsd.2022.32.2.3","DOIUrl":"https://doi.org/10.51316/jst.157.etsd.2022.32.2.3","url":null,"abstract":"Organic additives, i.e., fatty acid amide compounds, are typically used to reduce the viscosity of asphalt mixture at high-temperatures working operation. Present work focuses on preparing fatty acid amide from waste cooking oil and its characterization as an additive for bitumen. The role of synthesized fatty acid amide as an additive for bitumen was tested on the bitumen 60/70 penetration grade sample. The fatty acid amide was synthesized and characterized by FT-IR and NMR spectroscopy. It showed that the fatty acid amide was successfully prepared from the waste cooking oil due to the presence of the characteristic functional groups. The binders made from fatty acid amide and bitumen with different content of fatty acid amide were prepared and tested. It demonstrated that the kinetic viscosity of the binder reduced by 23 % at 0.7 wt% additive concentration at 140 ºC . Moreover, the penetration and softening point of the binder was also improved, which enhance the binder's physical properties when used at target temperatures.","PeriodicalId":17641,"journal":{"name":"JST: Engineering and Technology for Sustainable Development","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74393495","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}
Pub Date : 2022-04-15DOI: 10.51316/jst.157.etsd.2022.32.2.6
V. Dang, Thu Ha Pham Thi, V. Pham
While the electroosmosis of the first kind (equilibrium) is accepted widely, the electroosmosis of the second kind (nonequilibrium) is still controversial. In this work, the theory of electroosmosis slip, of either the first kind or of the second kind at electrolyte membrane system is revisited via our direct numerical simulation. The obtained results show that above a certain voltage threshold, the basic conduction state becomes electroconvectively unstable. This instability provides a mechanism for explaining the over-limiting conductance in concentration polarization at a permselective membrane. The most important work in our study is to examine the famous electroosmosis of the second kind formula suggested by Rubinstein and Zaltzman in 1999. Although their formula has been presented for a long time, there has been no work to validate its accuracy experimentally or numerically due to the difficulty in pinpointing exactly the extended space charge layer in their formula. By using direct numerical simulation, we could solve this problem and inspect the application range of their formula. This also helps to strongly confirm the relationship between the electroosmosis of the second kind and the instability in concentration polarization at electrodialysis membranes.
{"title":"Electroosmosis of the Second Kind on Flat Charged Surfaces - a Direct Numerical Simulation Study","authors":"V. Dang, Thu Ha Pham Thi, V. Pham","doi":"10.51316/jst.157.etsd.2022.32.2.6","DOIUrl":"https://doi.org/10.51316/jst.157.etsd.2022.32.2.6","url":null,"abstract":"While the electroosmosis of the first kind (equilibrium) is accepted widely, the electroosmosis of the second kind (nonequilibrium) is still controversial. In this work, the theory of electroosmosis slip, of either the first kind or of the second kind at electrolyte membrane system is revisited via our direct numerical simulation. The obtained results show that above a certain voltage threshold, the basic conduction state becomes electroconvectively unstable. This instability provides a mechanism for explaining the over-limiting conductance in concentration polarization at a permselective membrane. The most important work in our study is to examine the famous electroosmosis of the second kind formula suggested by Rubinstein and Zaltzman in 1999. Although their formula has been presented for a long time, there has been no work to validate its accuracy experimentally or numerically due to the difficulty in pinpointing exactly the extended space charge layer in their formula. By using direct numerical simulation, we could solve this problem and inspect the application range of their formula. This also helps to strongly confirm the relationship between the electroosmosis of the second kind and the instability in concentration polarization at electrodialysis membranes.","PeriodicalId":17641,"journal":{"name":"JST: Engineering and Technology for Sustainable Development","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75969930","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}
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