Bending and buckling responses of organic nanoplates considering the size effect
Trang: 2015-2029 Dao Minh Tien, Do Van Thom, Phung Van Minh, Pham Huy HieuTóm tắtAs humanity progresses, fossil fuel reserves are being increasingly exhausted, leading to increased focus on sustainable energy alternatives. Scientists are now researching solar panels that can efficiently convert solar energy into electricity for human use. This research employs a novel third-order shear deformation theory to investigate the static buckling and static bending behaviors of organic nanoplates, marking the first instance of such an approach being used. The formulas are computed using strain gradient theory to consider the impact of the size effect, where this size effect parameter is considered in both positive and negative cases. The plate's balancing equation is derived using the notion of virtual displacement, and the analytical solution is obtained using Navier's solution. The mathematical expression for deflection and critical buckling load in this study has been validated by comparing it with previously published analytical findings. This study also includes a set of numerical calculations to demonstrate the impact of certain geometric factors and the size effect on the static bending response and static buckling of organic plates. This study aims to assist designers in developing organic plate products that demonstrate optimal functionality in real-world applications
The moderating effect of trust on the adoption of electric motorcycles among road users
Trang: 2030-2044 Tran Dinh Minh, Nguyen Van Bien, Hoang Nhat Linh, Le Minh Truyen, Nguyen Phuoc Quy DuyTóm tắtMotorcycles with internal combustion engines fueled by fossil fuels dominate the traffic flow in major Asian cities, contributing significantly to air and noise pollution compared to other transport modes like walking, cycling, and public transport. To address this issue, many Asian countries are promoting the adoption of electric motorcycles to reduce air pollution and reliance on non-renewable energy sources. However, the adoption of electric motorcycles faces various challenges. This study investigates factors influencing the adoption of electric motorcycles in Vietnam. Structural equation model (PLS-SEM) software was used to analyze data gathered from 751 valid responses. The findings reveal that perceived usefulness has the most significant positive impact on the adoption of electric motorcycles, while perceived risk acts as a barrier to the adoption intention. Additionally, age moderates the relationship between perceived ease of use and adoption intention, and income level influences the correlation between perceived risk and the adoption of electric motorcycles. The study also discusses the policy implications, focusing on how motorbike manufacturers can further promote the adoption of electric motorbikes (EMs)
Trang: 2045-2057 Nguyen Thi Thanh HuongTóm tắtEnhancing the quality of public transport services, implementing effective parking fee policies, and developing park-and-ride facilities are common solutions that urban planners and city governments apply to encourage public transport use. However, estimating the impact of these measures on increasing public transport usage during the solution design process is challenging. This article proposes an approach to assess the effects of these measures in the solution design process, which policymakers or city governments can apply to formulate suitable policies and feasible measures aligned with the local context. The approach begins with a survey on travel behaviour, followed by formulating a mode choice model to assess the sensitivity of the mode share to factors affecting mode choice. This approach is applied to Da Lat city, and the research results indicate how to enhance public transport services, determine appropriate parking fee levels, and establish park-and-ride facilities to achieve a public transport share of 5%, 10%, 15%, or higher. One of the main research results shows that the Park and Ride solution is feasible. Additionally, to achieve a growth rate of public transport volume up to 10%, it is necessary to improve public transport quality services combined with an increase in car parking fees in the downtown area
Trang: 2058-2069 Tran The Hung, Nguyen Dinh Quang, Le Dinh AnhTóm tắtReducing aerodynamic drag and increasing flying object performance is an important task in aerospace engineering. The high drag occurs for blunt base models, which are not only for missiles, and projectiles but also for building, bridges. This study presents numerical results regarding subsonic flow characteristics over axisymmetric boattail models equipped with longitudinal grooves, with the number of grooves ranging from 2 to 12. The standard model has a fixed boattail length of 0.7D and an angle 22°. The investigation employs numerical simulation methods utilizing the Reynolds-averaged Navier-Stokes (RANS) equations with the k-ω SST turbulent model. The boundary layer was captured well by the current simulation. The numerical results are initially validated against both simulated and experimental data from previous studies, ensuring accuracy and reliability. The findings indicate that an increase in the number of grooves from 0 to 4 results in a slight increment in drag. However, as the number of grooves is further increased from 6 to 12, a significant reduction in the model's drag is observed. Additionally, the flow patterns around the boattail model are visually depicted and analyzed to explain the drag trend of the model with different groove configurations
Building an image processing program for the vehicle fire control system
Trang: 2070-2080 Xuan Tung VuTóm tắtIn the world, the integration of controlled weapons into combat vehicles has been done for a long time and many weapon manufacturers have utilized image processing software to enhance the combat effectiveness of weapon systems, resulting in positive outcomes. Fire control systems, especially fire control systems on vehicles, require requirements for processing speed, durability as well as flexibility, which are essential when fighting the enemy. Kernelized Correlation Filters image processing algorithms and Temple Matching algorithms have promoted the advantages of image processing with vehicle fire control system in the weapons field. In this article, from the analysis of the Kernelized Correlation Filters image processing algorithm and the Temple Matching algorithm on hardware platforms suitable for vehicle fire control systems, the authors built a software program based on taking advantage of the powerful parallel computing capabilities of GPUs applied to 12.7 mm gun fire control systems installed on vehicles. The experiments demonstrated the results of handling targets in the field after completely installing all components of the weapon complex on the vehicle
A design of computational fuzzy set-based semantics for extracting linguistic summaries
Trang: 2081-2092 Pham Dinh Phong, Nguyen Duc DuTóm tắtLinguistic summarization is to extract a set of summary sentences in the form of natural language, so-called linguistic summaries, from numeric data. The extracted linguistic summaries should be compact and diverse, and have a validity measure greater than a given threshold, so genetic algorithms are applied to extract such linguistic summaries. Besides, the interpretability of linguistic summary content is considered in recent studies in such a way that enlarged hedge algebras are applied to generate multi-semantic structures for linguistic words of linguistic variables ensuring the interpretability of the content of the linguistic summaries. However, the membership function of computational fuzzy-set-based semantics of linguistic words is usually in the shape of trapezoid. In this paper, a membership function of the form S function is applied to improve the quality of extracted linguistic summaries. Besides, the applied algorithm is parallelized to reduce running time. The experimental results with the creep dataset have demonstrated the effectiveness of the proposed method
Monomial asymptotic polynomials and applications to polynomial optimization problems
Trang: 2093-2103 Du Thi Thu TrangTóm tắtThe problem of polynomial optimization plays an important role in many fields such as physics, chemistry, and economics. This problem has received research attention from many mathematicians recently. In this paper, we study the polynomial optimization problem over a non-compact semi-algebraic set, for which its constraint set of polynomials G is asymptotic with a finite family of monomials. By changing variables via a suitable monomial mapping, we transform the problem under consideration into the polynomial optimization problem over a compact semi-algebraic feasible set. We then apply the well-known result that the optimal value of a polynomial over a compact semi-algebraic set can be approximated as closely as desired by solving a hierarchy of semi-definite programs and the convergence is finite generically, to obtain results in the general case when the cone C(G) is unimodular. In particular, in the case of polynomials in two variables, we solve the problem quite completely without requiring C(G) to be unimodular
Trang: 2104-2118 Trinh Thi Huong, Nguyen Duc AnhTóm tắtCurrently, high-speed railway systems are rapidly expanding worldwide, necessitating reliable and efficient mobile communication solutions. However, the Doppler frequency shift caused by the high speeds of trains presents significant challenges to communication systems, particularly those using OFDM in LTE. This paper presents a novel for Doppler frequency compensation in high-speed railway communication based on the results of estimating the train's velocity using machine learning algorithms. By leveraging advanced algorithm such as neural networks, our method dynamically predicts and compensates for Doppler shifts in real-time. In this proposed novel, the Doppler frequency value is calculated based on the actual train’s velocity and the scenario of a high-speed railway, then the Doppler frequency is used to compensate the carrier frequency offset (CFO) directly at the Access Point (AP) device on the train. We conduct simulations to evaluate the effectiveness of our proposed solution in a high-speed railway scenario. The results demonstrate a marked improvement in communication reliability and data integrity, highlighting the potential of machine learning to enhance the performance of mobile communication systems in high-speed railways. The results of the proposed model are evaluated based on the system’s bit error rate BER after the CFO compensation decreases and the ratio of average energy per bit (Eb) to noise power density (N0) (Eb/N0) increases. This shows that the proposed solution works effectively and reduces the system’s bit errors while improving the communication performance. This study opens new avenues for integrating intelligent systems in transportation networks, ensuring seamless connectivity, and improving passenger experience
Trang: 2119-2128 Nguyen Huy Cuong, Mai Dinh Loc, Pham Thi Thanh ThuyTóm tắtRecently, the application of textile-reinforced concrete (TRC) in thin-walled precast structures has gained significant attention. Among these innovations, the combination of TRC and reinforced concrete (RC) has emerged as an effective method for creating hybrid structural systems. This paper presents the experimental results analyzing the shear behavior of a hybrid deck slab structure consisting of TRC stay-in-place (SiP) formwork and RC components. Shear performance was evaluated using 3-point bending tests on four large-scale specimens with aspect ratios (a/d) varying from 1.6 to 2.3. The average load carried by the TRC SiP formwork prior to failure—due to textile reinforcement rupture—was approximately 26.3 kN, with compressive strains at the top edge ranging from 2.8 to 3.4 ‰, just below the concrete's ultimate strain. The findings demonstrate the versatility of TRC SiP-formwork, highlighting its adaptable cross-section and substantial load-bearing capabilities, making it particularly suitable for composite bridge deck applications. The specimens experienced both shear compression and diagonal shear failures. Moreover, the TRC SiP-formwork effectively mitigated transverse cracking at the interface, enhancing bond strength and improving overall structural performance
Trang: 2129-2138 Le Ha Linh, Hoang Viet Hai, Vu Ba Thanh, Do Anh Tu, Nguyen Duy TienTóm tắtOrthotropic steel bridge decks structures (OSBDs) have been widely used in long-span bridges to reduce the dead load of the bridge. However, over time, the asphalt wearing course of the bridge deck structure has shown many damages. Recently, ultra-high-performance concrete (UHPC) has been employed to repair and reinforce these structures. Therefore, this paper focuses on the effect of UHPC thickness on the mechanical behavior of the orthotropic deck. The five-point bending beam test model using the finite element method is used in this investigation to clarify the effect of UHPC thickness, the ratio of adhesion failure, and temperature on the mechanical behavior of the OSBDs. The UHPC thickness varies from 30 to 50 mm, the ratio of adhesion failure varies from 0.1 to 0.3, and the temperature changes from 30°C to 60°C. The results show that the presence of the UHPC layer significantly reduces the impact of adhesive layer damage and temperature on the behavior of the OSBDs
Trang: 2139-2153 Tu Sy QuanTóm tắtThe recycle of oyster shell as a component of concrete is a considerable solution around the world, not only ameliorate environment quality due to waste pollution but also decelerate the depletion of traditional aggregates. In this study, the oyster concrete is elaborated and performed in the order to determine many mechanic properties such as compressive strength, tensile strength or modulus of elasticity. These parameters are an important information, allowing to predict the shear strength of concrete in the structure using Glass Fiber Reinforced Polymer (GFRP) rebar, where a part of fine aggregate is replaced by oyster shell. Besides, many 3-points bending test were realized in several beams with different ratios of replacement. The presence of oyster shell crushed replacing the natural sand reduced many mechanic characteristics of concrete, including the shear behaviour. However, compared to theoretical predictions, the results given by experiment seems betters, although there is a diminution of shear strength in almost specimens. This argument leads to the possibility of using this kind of concrete with GFRP rebar in the design of manufacturing precast members, mainly under the load introducing the shear force
