Journal of Technical Education Science

Con lắc ngược quay là một mô hình quen thuộc và cơ bản trong lý thuyết điều khiển tự động. Tuy nhiên, giá tiền một mô hình là rất cao, không phù hợp điều kiện trang bị phòng thí nghiệm còn hạn chế ở Việt Nam. Các mô hình được tự chế tạo hiện nay thì không đáp ứng được thông số mô hình, dẫn tới việc áp dụng các giải thuật phụ thuộc vào mô hình không được thiết kế thành công. Bài báo đề xuất chế tạo mô hình con lắc ngược quay giá rẻ và dễ xây dựng cho các phòng thí nghiệm điều khiển trong hoàn cảnh Việt Nam. Mô hình rõ ràng trong cấu trúc, thông số hệ thống. Và khả năng ứng dụng hệ thống để hướng dẫn trong phòng thí nghiệm được chứng minh bằng cách áp dụng xây dựng giải thuật trên mô hình này với việc xây dựng giải thuật-swingup và cân bằng- dựa trên hệ động lực học hệ thống. Sau đó, khảo sát trên các bộ điều khiển và đáp ứng hệ thống sẽ cho thấy hiệu quả của mô hình thực này. Giải thuật cân bằng LQR được lựa chọn và giải thuật swing-up là phương pháp Furuta.

Compliant constant-torque mechanism (CTM) can produce an output torque that does not change within a prescribed input rotation range. This stability is maintained regardless of complicated sensorized control systems. Owing to the monolithic nature of the compliant mechanism, the device is more compact, lightweight, and portable, which is favorable to human joint rehabilitative devices or mobility-assisting devices. However, before approaching the stable range, the mechanism has to undergo a pre-loading range which usually accounts for one-third of the entire operational journey. In addition, the deformation of flexible segments is restricted due to the yield strength of the materials. This limited working range hampers other potential applications of compliant CTMs. This paper presents a novel design of a compliant 2-stage CTM with long-stroke by using serially connected curved beams that deform sequentially. The design process is implemented via a shape optimization scheme using genetic algorithm. Finite element analysis is used to characterize the constant-torque behavior of the CTM under static loading. A general design formulation is also proposed to synthesize this special kind of compliant mechanism. The results show that this CTM gets the stable torque range from 300 to 1100 over two stages with the deviation less than 4.3%.

Adsorption kinetics is an essential part in adsorption studies. The pseudo-first-order (PFO) and pseudo-second-order (PSO) models are frequently used to model the experimental dataset of time-dependent adsorption. The differential equations (based on reaction rate and rate law) of the PFO and PSO models are similar to those of chemical reactions (i.e., first and second order-kinetic reactions). The adsorption kinetics is illustrated through the plot of qt (the amount of adsorbate adsorbed by adsorbent at time t) vs. time. This plot includes two important regions (kinetic and equilibrium). The adsorption rate constant (k1(PFO) or k2(PSO), respectively) of the PFO or PSO models needs to be calculated from two regions. The appropriate selection of initial adsorbate concentrations for studying adsorption kinetics should be based on adsorption isotherm to ensure that adsorption sites in adsorbent (material) are highly (nearly fully) covered by adsorbate (solute). Only in this case, the rate constant of the adsorption is accurately obtained.

Corona pandemic has a strong influence on almost all fields all over the world, especially in education. In Vietnam, in the case study of the University of Technology and Education Ho Chi Minh City (HCMUTE), most of the lecturers being responsible for theoretical subjects are required to teach their students online during the outbreak of COVID 19. It is a crucial issue that needs efficiency from online learning. This study aims to evaluate the status and efficiency of online learning at HCMUTE. Altogether 108 students and 25 lecturers participated in the study. The qualitative data collection tool was a questionnaire that has open and closed questions related to the learning environment, the interaction relationships, and learning outcomes. The results show that there is a synchronous learning environment and plenty of digital tools used by most lecturers. About 74 percent of students are satisfied and keen on continuing online learning; a large number of lecturers would like to continue with blended learning. Besides, the study also found out some difficulties that focus on two main issues such as technical issues, and decreasing students’ activeness during online classes. The study also recommends three learning activities design stages that the lecturers can apply for their online teaching to encourage students to active learning. This research extends knowledge of pedagogy and orient the next online course design at UTEx.

Freeze drying is one of the most advanced drying technologies for food processing and preserving using temperature under 0oC or under the freezing point, and pressure of drying chamber environment under 4.58mmHg to process foods. This method helps to maintain the initial quality of proteins, lipids, carbohydrates, vitamins, bioactive substances and sensory activities… In this study, the calculation and design were carried out to find suitable technology parameters to make the freeze drying system in which the freezing process occurred inside the freeze drying chamber. Heat was transferred by short wavelength thermal radiation, l = 50´10-3 m. As a result, time of freeze drying had been shortened to 13.33h/batch. The system was successfully manufactured, showed the steadily working, producing the high quality products, and reduced products price. In the conditions of Vietnam, the freeze drying system replacing that of other countries is the indispensable factor to apply for processing and preserving foods.

Polychlorinated Naphthalenes (PCNs) have been included as new persistent organic pollutants (POPs) under Stockholm Convention in May, 2015. Thereafter, various studies working on the occurrence, toxicity and characteristics of PCNs in all environmental matrices and emission sources were conducted worldwide. However, these kinds of study have never been done in Vietnam, where has a high potential of PCNs pollution. Upcoming activities obeying the Stockholm Convention on limiting adverse effect of PCNs should be conducted as soon as possible by Vietnamese government. For the preparation, the relevant information on properties, sources of PCNs should be reviewed in advance. In this review paper, the characteristics of PCNs emitted from current sources and their atmospheric level measured worldwide were summarized. This review paper also offered diagnostic ratios those could be effectively used for distinguishing PCNs emitted/released or evaporated from technical mixtures and combustion-related sources. The information given in this review paper is useful for future studies in Vietnam.

The aim of this article is to describe the direct and potential impacts Erasmus+ Capacity Building Higher Education (CBHE) - Project called “Empowering Vietnamese VET teachers for transformation towards Education 4.0” (EMVITET)- after one year of implementation. Additionally, the survey findings also summarized the institutional and teachers’ personal experiences during the Covid-19 pandemic, which pushed Vietnamese institutions to rapidly transform their education to online environments. Qualitative data were collected with online questionnaires from six partner institutions and 35 teacher participants. The findings indicate that both individual teacher participants and partner institutions were given a boost to improve Education 4.0 competencies thanks to the participatory and collaborative approach of the EMVITET- project. The project was perceived as an useful external source for supporting the institutions’ management in organizing demanding online education during Covid-19 pandemic.

E-learning has become a trend in university education around the world. Also, the EMVITET Erasmus+ project in developing Education 4.0 has focused on developing e-learning. This study investigates the effect of critical success factors (CSFs) on e-learning at Da Nang University of Technology and Education (UTE-DN), a member of The University of Danang. Five categories were firstly identified via the literature and a questionnaire using the Likert scale was then carried out to evaluate the importance of each factor from students’ perspective. Analytical results indicated 20 CSFs that influence the success of e-learning. Internet quality, self-efficacy, content quality of the lectures, enthusiasm while teaching, and accessible and up-to-date learning materials are the top five influential factors that impact e-learning success. This study, thus, supports leaders and teachers at UTE-DN in making decisions and strategies about e-learning.

The most common automotive suspension systems have been used passive components with fixed damping coefficient and spring constant. They are two separate functions to reach a compromise between drive quality and handling performance. Because of the limit of structures, the passive suspension system could hardly enhance the two features at the same time. In recent years, the active suspension system has been widely used in a vehicle which can overcome the limitations of the passive suspension systems. Since there are many advantages to make the vehicle operate safer and quieter than the passive suspension system. The aim of this study is to develop a linear mathematical model of active and passive suspensions systems for quarter car models subjected to different road profiles using a Proportional Derivative Integral (PID) controller. After modeling and simulation of the suspension system using Matlab/Simulink, this study has been able to determine the parameter of PID controllers of active suspension in many different road surfaces and vehicle speeds to improve driving comfort. Another new point of this study is the Graphical User Interfaces to be a successful design. The users can enter the input parameters for Matlab processing and get the results, which can make system analysis faster and more convenient. The main outcomes of this paper are performed to investigate and compare the response between active and passive suspension systems. Through the analysis of the simulation results, this research has demonstrated the feasibility, reliability, and they can be applied to propose a further improvement of the kinematic and dynamic characteristics of the vehicle active suspension system.

This paper presents a nonlinear controller with dynamic compensation for six degrees of freedom (6-DOF) manipulator Denso VS-6556 in practice. The manipulator is a complex nonlinear system with some limitations when applying a linear controller to control it. The nonlinear controller combines proportional derivative, and dynamic compensation is established to deal with this problem. The PD control is a linear controller, and dynamic compensation can cancel the nonlinear parts in the system. Therefore, the tracking problem is expected to result in a good performance. The stability and resilience of the entire system are examined using a Lyapunov technique. The test bench is built to ensure the conditions for experimentation; it includes card PCI QUAD04s, NI PCI-6713, industrial computer 610H Advantage, and MATLAB/Simulink in practice. Finally, the suggested control is subjected to the 6-DOF manipulator Denso 6556 and compared with the PD control to verify the effectiveness of the controller.