https://tcsj.utc.edu.vn/index.php/tcgtvt/issue/feed 2025-05-22T13:44:34+07:00 Tạp chí Khoa học Giao thông vận tải tcsj@utc.edu.vn Open Journal Systems https://tcsj.utc.edu.vn/index.php/tcgtvt/article/view/2505 2025-05-19T14:51:44+07:00 Trần Văn Giáp vpdt_1279@utc.edu.vn 2025-05-19T14:51:44+07:00 ##submission.copyrightStatement## https://tcsj.utc.edu.vn/index.php/tcgtvt/article/view/2399 2025-05-20T14:44:37+07:00 Thinh Le Tien thinh.letien@phenikaa-uni.edu.vn Huan Duong Thanh

Amorphous silica is widely used in advanced materials and nanocomposites due to its unique mechanical and structural properties. Understanding its mechanical behavior and the characteristics of silica nanoparticles is essential for optimizing their performance in various applications. This study numerically investigates the mechanical properties of amorphous silica material and the formation of silica nanoparticles using Molecular Dynamics (MD) simulations. Amorphous silica is generated from a crystalline structure through a melt-and-quench procedure. To determine its mechanical properties, six virtual mechanical tests are performed to compute the apparent elasticity tensor, from which the elastic moduli are extracted via an isotropic projection. The results indicate that amorphous silica exhibits nearly isotropic mechanical behavior, with high stiffness characterized by a bulk modulus of 36.84 GPa, a shear modulus of 30.49 GPa, a Young’s modulus of 71.69 GPa, and a Poisson’s ratio of 0.18. Additionally, the study explores the formation of silica nanoparticles with radii of 1.5 nm, 3.0 nm, and 4.8 nm. The analysis reveals that surface roughness increases as nanoparticle size decreases, which may have implications for interfacial interactions in composite materials. These findings contribute to the understanding of amorphous silica’s mechanical behavior and its potential application as a reinforcing nanomaterial in polymer composites

2025-05-15T00:00:00+07:00 ##submission.copyrightStatement## https://tcsj.utc.edu.vn/index.php/tcgtvt/article/view/2427 2025-05-20T14:44:37+07:00 Trang Pham Minh pmtrang@utc.edu.vn Vinh Vu Duy Chaigneau Alexis

The Quy Nhon port in Vietnam is a key hub for trade and economic development in Binh Dinh province but is significantly impacted by sea-level (SL) variability, which can affect shipping and port operations. This study analyzes sea level variations at Quy Nhon port from 1987 to 2023 using monthly tide gauge data. The Empirical Mode Decomposition method applied to this dataset, identifies four dominant modes: an annual cycle (53.7% of variance, 23.7 cm amplitude) primarily driven by monsoon wind reversals, a semi-annual cycle (27.1%, 13.2 cm amplitude), and interannual (2.3 years, 7 cm amplitude) and decadal (10.7 years, 4 cm amplitude) variations. These latter modes are significantly anti-correlated with the El Niño-Southern Oscillation (ENSO, r = -0.34) and Pacific Decadal Oscillation (PDO, r = -0.45), indicating that warm (cold) phases of these climate modes correspond to lower (upper) SL. A long-term linear SL rise of 1.5–2.1 mm/yr was also observed. These findings provide key insights for SL forecasting and maritime safety, emphasizing the need to refine predictions and better understand underlying physical processes

2025-05-15T00:00:00+07:00 ##submission.copyrightStatement## https://tcsj.utc.edu.vn/index.php/tcgtvt/article/view/1938 2025-05-20T16:48:31+07:00 Khoi Tran Van tvkhoi.ktd @utc.edu.vn Anh An Thi Hoai Thu

Vietnam, situated near the equator, receives high solar radiation, making it a crucial factor in addressing the urgent global shift to renewable energy sources. This transition aims to reduce CO2 emissions and achieve carbon neutrality by 2050. In the context of effectively harnessing solar energy, this paper presents a solution for identifying the location and power of renewable energy systems integrated into the distribution network. The objective is to minimize transmission power loss and voltage fluctuations while maximizing profits. The proposed solution involves using the Newton-Raphson algorithm to determine energy distribution on the power network in specific scenarios. Subsequently, the Hill Climbing algorithm is applied to identify the optimal location for deploying the renewable energy system on the power network. Moreover, a method for determining the power of renewable energy systems is implemented to minimize the objective function utilizing the Newton method. Experimental validation on the IEEE 33 bus and 69 bus test systems demonstrates that the proposed methodology consistently achieves optimal results expediently, underscoring its efficacy

2025-05-15T00:00:00+07:00 ##submission.copyrightStatement## https://tcsj.utc.edu.vn/index.php/tcgtvt/article/view/2168 2025-05-22T13:44:34+07:00 Ha Do Viet dovietha@utc.edu.vn

In recent years, wireless communications have been harnessed to enhance the performance, reliability, and passenger experience of high-speed railways (HSR). However, the demanding requirements of HSR systems, including high data rates, reliability, and low latency, present significant challenges for wireless communication technologies. One promising and effective approach to address these challenges is to increase system capacity through the use of multiple-input multiple-output (MIMO) techniques. Our study investigates radio wave propagation in high-speed railway environments using MRS (Mobile Relay Station). Through simulations based on a non-stationary geometry-based stochastic channel model, we evaluate the performance of MIMO techniques. Our findings reveal that while MIMO can significantly enhance system capacity, its practical gains in HSR environments are lower than predicted by theoretical models, primarily due to the significant deviations from ideal channel conditions. By analyzing numerical results on the effectiveness of MIMO configurations in enhancing system capacity, the paper determines the optimal number of transceiver antennas required to achieve the desired capacity increase without compromising design complexity. The evaluation methodology presented in this paper can serve as a valuable tool for predicting the performance of HSR communication systems before investing in costly hardware implementations

2025-05-15T00:00:00+07:00 ##submission.copyrightStatement## https://tcsj.utc.edu.vn/index.php/tcgtvt/article/view/2213 2025-05-20T14:44:37+07:00 Nguyen Thanh Lich lichnt@utc.edu.vn Pham Thanh Loan

The Interior Permanent Magnet Synchronous Motor (IPMSM) has been widely employed as a preferred choice for electric vehicle (EV) because of its advantageous characteristics such as high efficiency, high-power density, and a robust operation. This paper focuses on the control of an IPMSM for EV applications, with emphasis on smooth transitions over a wide speed range, including both normal and high-speed operating regions. A comprehensive review of state-of-the-art IPMSM control methods is provided, followed by fundamental machine principles. Over-modulation techniques are then presented to effectively manage the maximum voltage of the DC-link source, a critical aspect for EV powertrains. In order to control the machine over a wide-speed range, a flux-weakening method has to be adopted by combining the conventional space vector modulation (SVM) in the normal speed range and the voltage angle control in the high-speed regions. A key innovation of this study is the use of the Newton-Raphson method to determine the optimum operating point of the IPMSM, minimizing the stator current for a given torque demand. This optimization not only maximizes the torque capability over the entire speed range, but also enhances the dynamic performance of the system, which is essential for EV applications requiring rapid and precise response. The proposed control strategy combines SVM with overmodulation techniques, enabling seamless transitions between low- and high-speed regions. Simulation results are used to validate the effectiveness of the proposed control strategy, demonstrating stable and robust performance under varying speed and load torque conditions, highlighting its potential for applications in wide-speed-range IPMSM-based EV systems

2025-05-15T00:00:00+07:00 ##submission.copyrightStatement## https://tcsj.utc.edu.vn/index.php/tcgtvt/article/view/2222 2025-05-20T14:44:37+07:00 Chi Vo Minh pvngoc@dut.udn.vn Hai Nguyen Minh Lan Nguyen Ngoc Pham Van Huong Nguyen Van Hung Nguyen Duc

Self-sensing concrete is an advanced material capable of monitoring its stress or strain through changes in its electrical resistance. A novelty of this study lies in its focus on the electrical resistance response, not of an individual concrete specimen as in most previous studies, but rather on a pair of self-sensing concrete blocks under non-destructive compression, targeting future applications in large-scale load-weighing systems. The self-sensing concrete samples in the study were fabricated by incorporating carbon fibers into the concrete mixture, creating a conductive network within the material. The experimental setup involved subjecting a robust steel plate to incremental compressive loads, supported by a pair of self-sensing concrete blocks. The corresponding changes in electrical resistance were measured throughout the loading process. Results indicated that each concrete block might exhibit different responses, but their summed response is nearly linear with a high R-squared value above 0.9 and relatively consistent between experimental cases. Additionally, the study highlighted that variations in the current intensity do not significantly affect the resistance response. On the other hand, the locations of concrete blocks relative to the load were identified as a crucial factor affecting the resistance response. Within the scope of this study, the error in the predicted load value corresponding to the resistance variation when experimental parameters are changed is below 10.7%.The findings of this study demonstrate the significant potential of using self-sensing concrete for large-scale load-weighing systems in future smart traffic and logistics management systems

2025-05-15T00:00:00+07:00 ##submission.copyrightStatement## https://tcsj.utc.edu.vn/index.php/tcgtvt/article/view/2274 2025-05-20T14:44:37+07:00 Binh Hoang Nam phuongtltv@utc.edu.vn Phuong Tran Thu Vinh Hoang Duc Nghi Le Van

Accurate discharge forecasting is crucial for effective water resource management, flood risk mitigation, and hydrological planning, particularly in regions prone to extreme weather events. This study evaluates the performance of a Long Short-Term Memory (LSTM) network in predicting river discharge at the Hoa Duyet hydrology station. The prediction model is developed using rainfall data from the Ngan Sau river basin, collected over a 49-year period from 1975 to 2023. The model's accuracy was assessed across a range of lead times (1-day, 3-day, 5-day, and 7-day) and time lag length (365, 90, 30, 10, and 7 days). It was revealed that short-term forecasts (e.g., 1-day) consistently achieved high accuracy, with the time lag length 90-day yielding the best Nash-Sutcliffe Efficiency (NSE) of 0.864. Seasonal analysis indicated the reliability of the model for the rainy season (NSE = 0.863), but lower accuracy during the dry season (NSE = 0.582), reflecting the challenges of predicting low-flow dynamics. The model also demonstrated reasonable accuracy in predicting annual runoff peaks, with an average error of 91.75 m³/s, although discrepancies were observed in specific years. These findings highlight the LSTM model's capacity to adapt to diverse temporal configurations and hydrological conditions, making it a valuable tool for discharge prediction while emphasizing the need for further optimization in low-flow and extreme event scenarios

2025-05-15T00:00:00+07:00 ##submission.copyrightStatement## https://tcsj.utc.edu.vn/index.php/tcgtvt/article/view/2433 2025-05-20T14:44:37+07:00 The Vu Van thom.dovan@lqdtu.edu.vn Thom Do Van

Microelectromechanical devices are being used much more in science and technology to reduce energy consumption and increase accuracy. The design of mechanical structures in these devices requires reducing the cost of testing and prototype manufacturing. It is necessary to define the essential parameters in designing the microstructures to reduce the design time. This paper presents a simulation method to determine the influence of the geometrical parameters of the micro-beam models with Crab-shaped used in the micro-mechanical structures on the equivalent stiffness. The significant parameters influencing the rapid change of equivalent stiffness are shown using the local sensitivity analysis technique and the surface response in the ANSYS Workbench. The results show that the length of the sensing bar with the convex curve and the maximum deviation is 76% for the equivalent stiffness, while the width of the beam with the concave curve gives the maximum value of 400% at the same 70% of the variation of each geometrical parameter. The local sensitivity analysis values for the length of the driving and sensing bar, and the width of the crab-shaped beam are -1.4485, -0.2786, and +2.0355, respectively. These analysis results are essential for choosing the suitable value for the geometrical parameters of the micromechanical structure according to the proposed resonant frequency in further studies

2025-05-15T00:00:00+07:00 ##submission.copyrightStatement## https://tcsj.utc.edu.vn/index.php/tcgtvt/article/view/2438 2025-05-20T14:44:37+07:00 Hung Nguyen Van nguyenngoclan@utc.edu.vn Nguyen Ngoc Lan Thuy Pham Thi Thanh Lam Nguyen Bao

The ballastless track structure (slab track) structure is commonly used in high-speed railway construction today. For this type of railway structure, the cement asphalt mortar polymer (CAM) layer plays an important role in damping, creating smoothness, reducing noise and ensuring simultaneous operation of the structure. Therefore, the CAM layer needs to be designed and manufactured to ensure ease of construction, strength and integrity for the entire slab track structure. This paper presents the initial experimental research results on the technology of CAM layer materials. The experimental studies were evaluated based on mixtures with asphalt/cement (A/C) ratios varying from 0.3, 0.4, 0.5, 0.6, and 0.7, respectively. The results of the research showed that, when the ratio of A/C increased, the flow time, flexural strength and compressive strength decreased. This trend of results was also completely consistent with the results of microstructural analysis by scanning electron microscope of mortar samples at 7 days of age

2025-05-15T00:00:00+07:00 ##submission.copyrightStatement##