Tạp chí Phát triển khoa học & công nghệ: chuyên san Kỹ thuật & Công nghệ最新文献

{"title":"Passivity - based control using genetic algorithm for a DC-DC boost power converter","authors":"Minh Ngọc Huỳnh, Hoài Nghĩa Dương, Vĩnh Hảo Nguyễn","doi":"10.32508/stdjet.v6i2.1053","DOIUrl":"https://doi.org/10.32508/stdjet.v6i2.1053","url":null,"abstract":"In this paper, a passivity – based control of a DC-DC boost power converter using genetic algorithm is proposed. The output of a DC-DC power boost converter is an inductor current. Its input is duty ratio . Using a co-ordinate transformation of state variables and control input, a DC-DC boost power converter is showed to be passive. A new plant is zero-state observable and the equilibrium point at origin of this plant is asymptotically stable. Then, a passivity - based control law is applied to this plant so that a voltage of capacitor x2 is equal to a value of desired voltage Vd when changing control input, duty ratio . The parameters of the passivity – based controller are also adjusted optimally by genetic algorithm using decimal encoder. Simulation results of a passivity – based control are good when the input voltage E, the load resistor R and the desired voltage Vd are varied. With variations of desired voltage Vd, the passivity – based controller supplies small value of IAE (integral absolute error of Vd and x2), small error, and short settling time Finally, simulation results show that the passivity – based control using genetic algorithm is better than the passivity – based control.","PeriodicalId":486088,"journal":{"name":"Tạp chí Phát triển khoa học & công nghệ: chuyên san Kỹ thuật & Công nghệ","volume":"2010 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136208453","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 in vivo antifungal activity of extracts from Jamaica cherry Muntingia calabura l. leaves","authors":"Nguyen Hoang Phuc Nguyen, Binh Quang Hoang, Ngoc Thao Ngan Trinh, Katleen Raes, Trung Thien Le","doi":"10.32508/stdjet.v6i3.1028","DOIUrl":"https://doi.org/10.32508/stdjet.v6i3.1028","url":null,"abstract":"Previous studies on M. calabura (Jamaica cherry) leaves reported the presence of polyphenols, flavonoids, glycosides, and tannins. However, the deep research focus on the antifungal activity of Jamaica cherry leaf extract (JCLE) is still limited. Hence, the current study was conducted on JCLE samples by using various solvents, i.e., 70% ethanol, 70% methanol, and 70% acetone, and then evaluating their antifungal activity. Analytical results showed that JCLE could be used as a natural antifungal potential agent against mold-causing spoilage in fruits. Specifically, the ethanolic extract had a strong inhibition of Colletotrichum gloeosporioides and Lasiodiplodia theobromae. While the methanolic and acetonic extracts prevented sharply the growth of Alternaria alternata and Fusarium equiseti, respectively. Generally, the ethanolic extract was able to inhibit the various mold strains better than the other solvents. Furthermore, the results showed that the percentage inhibition of radial growth (PIRG) of JCLE increased gradually as the concentration increased from 4000 to 40000 mg GAE/kg. The highest data obtained for C. gloeosporioides, A. alternata, F. equiseti, and L. theobromae were 53.29%, 57.03%, 54.81%, and 75.03%, respectively. In vivo experiment, the samples were treated with and without JCLE (the control sample) occuring the black spots caused by C. gloeosporioides on mango’s surface after 21 days and 30 days of storage at 12 ± 2 °C, respectively. Whereas the TSS and TA values of both samples were similar. While the visual appearance of the control was more yellow compared to the samples treated with JCLE. In conclusion, JCLE was able to significantly delay the development of pathogenic mold, though it quite inhibited the maturation of mango fruit. Further studies may be needed to evaluate the phtychemical profile of M. calabura extract to gain a deeper understanding of its antifugal activity.","PeriodicalId":486088,"journal":{"name":"Tạp chí Phát triển khoa học & công nghệ: chuyên san Kỹ thuật & Công nghệ","volume":"145 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135103833","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":"Accelerating the nonlinear analysis of hyper-elastic behavior by GMDH-assisted Newton-Raphson scheme","authors":"Minh Ngoc Nguyen","doi":"10.32508/stdjet.v6i3.1034","DOIUrl":"https://doi.org/10.32508/stdjet.v6i3.1034","url":null,"abstract":"This paper presents an accelerated iterative scheme for nonlinear problems. Commonly, analysis of nonlinear behavior is conducted by the Newton-Raphson (NR) method. It is well-known that the number of iterations required depends on the deviation between the “starting point” and the converged solution. In practice, the solution of previous load step is taken as the “starting point”, while the converged solution of the current load step is not known beforehand. Therefore, difficulties or even non-convergence may occur. Recently, it is suggested that a neural network is employed to predict the solution of the current load step. This prediction is then used as the “starting point” for NR scheme. It is expected, that the true converged solution (of current step) is closer to the prediction by neural network than to the solution of previous load step. As a result, the scheme becomes faster due to less iterations. Obviously, any techniques for time-series forecasting can be used. Here, the Group Method of Data Handling (GMDH) is proposed. Loosely speaking, GMDH is a feedforward neural network without backpropagation. Practically, the GMDH-assisted NR scheme should not take longer time than conventional NR scheme. The advantage of GMDH is fast computation; however, the accuracy may be not as high as a network that has backpropagation. Therefore, careful consideration on the construction of GMDH network is needed. In the current work, the performance of GMDH-assisted NR scheme is investigated in analysis of hyper-elastic behavior, which involves both geometrical and material nonlinearity. A study on the influence of activation function on the accuracy is presented. Also, it is found that prediction for incremental displacement (between the current load step and the previous load step) could be better than prediction of displacement of the current load step.","PeriodicalId":486088,"journal":{"name":"Tạp chí Phát triển khoa học & công nghệ: chuyên san Kỹ thuật & Công nghệ","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135059760","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":"Research and Develop the Motion Controller in the Mechanical Servo System","authors":"Minh Tuan Nguyen, Thinh Ha Quang Ngo","doi":"10.32508/stdjet.v6i3.968","DOIUrl":"https://doi.org/10.32508/stdjet.v6i3.968","url":null,"abstract":"In the field of mechanical engineering, the precision and real-time of high-performance manufacturing machine plays an important role. Recently, some solutions for servo system could overcome these drawbacks. Therefore, a design of motion controller to manipulate the highly precise position control and stability. The investigation of both hardware design and software programming is presented in this work. In addition, overall system is created in the real-world application. The use of the seven segments polynomial in motion generator provides an intuitive examination. From these results, it is clarified that the effectiveness and feasibility of our design and control is proper for industrial applications","PeriodicalId":486088,"journal":{"name":"Tạp chí Phát triển khoa học & công nghệ: chuyên san Kỹ thuật & Công nghệ","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135102006","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":"Dynamic behavior of sandwich beam with agglomerated carbon nanotube reinforced face sheets under a moving mass","authors":"Thom Thi Tran, Hoai Thi Thu Bui, Kien Dinh Nguyen","doi":"10.32508/stdjet.v6i1.1054","DOIUrl":"https://doi.org/10.32508/stdjet.v6i1.1054","url":null,"abstract":"In this paper, the dynamic behavior of carbon nanotube (CNT) reinforced composite sandwich beams under a moving mass taking into account the influence of the CNT agglomeration is investigated by the finite element method. The sandwich beams composed of a homogeneous core and two face layers made from carbon nanotube–reinforced composite (CNTRC) material. The two-parameter micromechanical model is adopted to describe the agglomeration of the CNTs, and the Eshelby–Mori–Tanaka approach is used to estimate the effective material properties of the composite face layers. Based on a third-order shear deformation beam theory, a beam element in which the transverse shear rotation, not the conventional section rotation, is employed as an independent variable is formulated and used to establish the discretized equation of motion for the beams. Using an implicit Newmark method, dynamic characteristics such as the time histories for mid-span deflections and the dynamic magnification factors are obtained for a sandwich beam with simply supported ends. The accuracy of the derived beam element is confirmed by comparing the results obtained in the present work with the published data. The numerical result reveals that the CNT volume fraction and the CNT agglomeration have a significant influence on the dynamic response of the sandwich beams. The dynamic magnification factor is found to be decreased with an increase of the CNT volume fraction, but it is higher for the case of the severse CNT agglomeration. A parametric study carried out to highlight the effects of the CNT reinforcement and the mass velocity on the dynamic behavior of the sandwich beams. The influence of the layer thickness ratio on the dynamic response of the composite sandwich beams is also studied and discussed.","PeriodicalId":486088,"journal":{"name":"Tạp chí Phát triển khoa học & công nghệ: chuyên san Kỹ thuật & Công nghệ","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136203578","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":"Synthesis of Na3SbS4 solid electrolyte from aqueous solution and its application in solid state rechargeable batteries","authors":"Anh Tu Tran, Tan Thi Pham, Huu Huy Phuc Nguyen","doi":"10.32508/stdjet.v6i2.1037","DOIUrl":"https://doi.org/10.32508/stdjet.v6i2.1037","url":null,"abstract":"The tetragonal Na3SbS4 solid electrolyte was synthesized from aqueous solution in this study. The XRD results showed that the peak separation at 2θ = 30.1 and 35.1 º might from a defect in the crystal structure of t-Na3SbS4. The results of Rietveld analysis showed that the crystal structure of the Na3SbS4 sample after heat treatment belongs to the space group P-421c with the reliability coefficients Rwp=14.959%, Rp=11.690%. The lattice parameters are a = b = 7.1554(13) Å and c = 7.2829(13) Å. The pressure dependence in the pelletizing process of the ionic conductivity of the solid electrolyte t-Na3SbS4 was investigated and the pellets made at a pressure of 550 MPa had the highest ionic conductivity among the prepared samples, reaching a value of 6.0x10-4 Scm-1 at 25 ºC. The activation energies for the transport of Na⁺ ions in the prepared samples were 23, 24, 26 and 24 kJ mol-1 for pellets formed at pressures of 330, 403, 477 and 550 Mpa, respectively. These results demonstrate that the ion conduction mechanism is independent of the pellet forming pressure but the ionic conductivity at 25 ºC is directly proportional to those values. In addition, the electrochemical stability of Na3SbS4 was also evaluated through the discharge-charge characteristics of the battery cell TiS2−Na3SbS4|Na3SbS4| Na15Sn4. In the first discharge - charge cycle, the Coulomb efficiency was about 92.7% and higher than 99% from the second cycle onwards.","PeriodicalId":486088,"journal":{"name":"Tạp chí Phát triển khoa học & công nghệ: chuyên san Kỹ thuật & Công nghệ","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136204427","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":"Evaluation of the distribution of COVID-19 particles in an Isolation room to reduce the possibility of transmission via CFD simulation","authors":"Viet Tan Tran, Yen Phi Hoang Duong, Tan Minh Le, Duc Tan Le","doi":"10.32508/stdjet.v6i1.1048","DOIUrl":"https://doi.org/10.32508/stdjet.v6i1.1048","url":null,"abstract":"The outbreak and prolonged COVID-19 pandemic has caused a population decline as well as a profound impact on the global economy, the COVID virus spreads highly in the air through the process of sneezing, contact leads to many dangers to the health and safety of people around the world. Many simulation studies have been carried out to predict the risk of spread, as well as to find solutions to limit the infection when spreading sneeze droplets in the air. In this study, the motion and distribution of droplets containing coronaviruses emitted by coughing or sneezing in the isolation room at Ho Chi Minh City, Vietnam National University were investigated using ANSYS Fluent software. The airflow in the isolation room was simulated by a 3D turbulence model and energy equation using the finite volume method (FVM) with a domain of isolation room solved for appropriate boundary conditions. The effect of ventilation airflow speed and the size of droplets on the distribution of particles in the air were investigated by the Lagrangian particle trajectory analysis method. The CFD analysis result showed that the velocity distribution, turbulent kinetic energy, and flow dynamics had strongly affected the reducing rate of average droplet concentration in the isolation room. Specifically, the study focused on the dispersion of liquid droplets containing the virus under fixed operating conditions of ventilation systems and exhaust fans, with a flow rate of 840 m3/h. Under these conditions, the retention time of liquid droplets was determined to be 37.5 seconds, corresponding to droplet diameters ranging from 5 to 100 micrometres. The results indicate that the presence of particles in the room gradually becomes diluted over time due to the continuous circulation of air. The ability of air to diffuse within the vicinity of the occupant's position and the limited spread of small particles within the room demonstrate that the operating conditions are suitable.","PeriodicalId":486088,"journal":{"name":"Tạp chí Phát triển khoa học & công nghệ: chuyên san Kỹ thuật & Công nghệ","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136202313","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":"Evaluating some factors affecting the loading process of quercitin and rutin into the niosome by ethanol injection method","authors":"Hien Minh Nguyen, Minh Binh Do, Manh Huy Tu Le, Phuoc Thuan Tran Nguyen, Tri Minh Le","doi":"10.32508/stdjet.v6i1.1056","DOIUrl":"https://doi.org/10.32508/stdjet.v6i1.1056","url":null,"abstract":"Niosome is a nanoparticle system with high application value and suitable for the current trend of drug delivery system development with many advantages in controllability, stable release, and target orientation. The active compounds rutin and quercetin have diverse pharmacological effects, although there are many challenges in application. This study aims to investigate the factors affecting the loading capacity of the bioactive compounds in the synthesis of niosomes by the ethanol injection method. Based on the investigation of the influence of surfactants as well as rutin and quercetin content to evaluate the ability to form structure and entrapment efficiency of niosomes. The resulting niosome has a round shape and a relatively uniform density, with the formula used, being a mixture of span 60 and tween 60 with a ratio of 6:4. The optimized niosomes using this ratio have a quercetin entrapment efficiency of 60 .8% and rutin reached 20.5% with the content of 20-25 mg of the standards. The combination of two surfactants, span 60 and tween 60, creates a niosomal structure that is both small in size, difficult to agglomerate and has high stability, suitable for providing prolonged action and storage. This formulation shows that quercetin had more than three times higher capture efficiency than rutin.","PeriodicalId":486088,"journal":{"name":"Tạp chí Phát triển khoa học & công nghệ: chuyên san Kỹ thuật & Công nghệ","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136203324","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":"PPG Signal and application in the medical field","authors":"Khanh Duy Phan, Thanh Tung Luu, Duy An Huynh","doi":"10.32508/stdjet.v6i1.1084","DOIUrl":"https://doi.org/10.32508/stdjet.v6i1.1084","url":null,"abstract":"The ascent of remote health examination is a burgeoning trend in healthcare, aimed at tackling the challenge of hospital overload and streamlining the process of patient monitoring. To achieve these laudable goals, a device that is both efficient and capable of extracting critical health indicators is of paramount importance. Enter photoplethysmography (PPG) technology - a compact and user-friendly device that offers a wealth of health-related information. PPG is an optical, non-invasive method of measuring changes in blood volume in tissue by illuminating the skin and detecting variations in light absorption caused by blood flow. This technique has a multitude of applications, including the measurement of blood oxygen saturation, the estimation of blood pressure, the assessment of vascular aging, and the detection of arrhythmias. Therefore, it presents a promising avenue in addressing the challenge of hospital overload. This article provides an all-encompassing overview of photoplethysmography (PPG) technology, elucidating the underlying principles and highlighting its noteworthy applications. Specifically, the article expounds on the use of PPG in measuring blood oxygen saturation, estimating blood pressure, assessing vascular aging, and detecting arrhythmias. Despite the advantageous applications of PPG, there are still some issues that need to be addressed, such as the limited availability of PPG data sets in certain populations, the sensitivity of PPG signal to motion and ambient conditions, and a lack of clarity about the nature of PPG which leads to the absence of standard criteria in sampling and interpretation of PPG in its applications. And these issues are also thoroughly discussed in the paper.","PeriodicalId":486088,"journal":{"name":"Tạp chí Phát triển khoa học & công nghệ: chuyên san Kỹ thuật & Công nghệ","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136203582","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}