Search Results (97)

Circular economy is a crucial strategy for achieving sustainable development. The use of solar PV, which is a renewable energy source, has been considered a popular indicator to measure and evaluate the circularity of an economy and enterprises. The recycling of solar PV panels optimises resource use and reduces the need for virgin materials. However, it does not automatically indicate an environmental advantage if the recovering and recycling processes are energy- or emission-intensive. The paper applies life cycle assessment to quantify the material demand for the Italian solar PV sector and contributions of solar PV end-of-life strategies to the enhancement of the circular economy. It is identified that the material intensity of the Italian solar PV sector increases from 4.67 g Sb eq to 5.20 g Sb eq per MWh by 2040 due to the change in technology mix. At the same time, the total material demand, as well as demand for specific materials, increases over the years, from 2008 to 2040. The strategy on recovery, recycling and reintegration of materials slightly reduces the material demand, from 816 tonnes Sb eq to 814 tonnes Sb eq in 2040. It also brings the benefits of reducing all the life cycle impacts, such as greenhouse gas emissions, energy demand, etc. Full article

This paper presents a novel wireless control framework for electric drive systems by employing a fuzzy brain emotional learning neural network (FBELNN) controller in conjunction with a Disturbance Observer (DO). The communication scheme uses chaotic system dynamics to ensure data confidentiality and robustness against disturbance in wireless environments. To be applied to embedded microprocessors, the continuous-time chaotic system is discretized using the Grunwald–Letnikov approximation. To avoid the loss of generality of chaotic behavior, Lyapunov exponents are computed to validate the preservation of chaos in the discrete-time domain. The FBELNN controller is then developed to synchronize two non-identical chaotic systems under different initial conditions, enabling secure data encryption and decryption. Additionally, the DOB is introduced to estimate and mitigate the effects of bounded uncertainties and external disturbances, enhancing the system’s resilience to stealthy attacks. The proposed control structure is experimentally implemented on a wireless communication system utilizing ESP32 microcontrollers (Espressif Systems, Shanghai, China) based on the ESP-NOW protocol. Both control and feedback signals of the electric drive system are encrypted using chaotic states, and real-time decryption at the receiver confirms system integrity. Experimental results verify the effectiveness of the proposed method in achieving robust synchronization, accurate signal recovery, and a reliable wireless control system. The combination of FBELNN and DOB demonstrates significant potential for real-time, low-cost, and secure applications in smart electric drive systems and industrial automation. Full article

This study aims to explore the associations between menstrual health, lifestyle behaviors, biological traits, and coping strategies among female students at a Vietnamese medical university. A cross-sectional survey was conducted among 884 female students across five academic majors. Data on demographics, menstrual patterns, biological characteristics, lifestyle behaviors, and coping mechanisms were collected. Statistical analyses included descriptive statistics, correlation, and logistic regression to identify significant predictors of self-reported menstrual changes post university admission. Of the 884 participants, 49.8% reported menstrual changes after entering university. Among the lifestyle-related factors, increased daily electronic use (mean = 5.83 h) and later bedtimes (mean = 23:58) were associated with menstrual change (p < 0.01). Older age and higher academic year emerged as significant predictors of menstrual changes (p < 0.001). Additionally, students with blood groups A and B exhibited a higher risk compared to those with group O (p < 0.05), and Rh-positive status was also significantly associated with menstrual changes (p = 0.05). In terms of knowledge and coping practices, students who had premenstrual syndrome awareness since school were significantly less likely to report menstrual changes (p = 0.003). Although use of pain relief, particularly painkillers, correlated with higher reported pain severity, it was not directly linked to menstrual change. On the other hand, clinic consultations were positively associated with menstrual changes (p = 0.003), while students who relied on their mothers as counselors exhibited a protective association (p = 0.001). Menstrual health in university-aged women is influenced by a complex interplay of lifestyle behaviors, biological traits, and menstrual knowledge. Early education and structured coping support may serve as protective factors. The findings call for targeted menstrual health programs in university settings. Full article

Herein, we study a method for developing a broad-emission emitter that can emit radiation from the visible light to NIR regions. Firstly, an NIR phosphor’s optical properties (e.g., scattering vs. weight concentration, conversion efficiency, and emission spectra under blue and red light excitation) are investigated. Then, pcW-LEDs encapsulated with NIR down-conversion phosphor samples are prepared to test these optical properties. The results show that pcW-LEDs encapsulated with the NIR phosphor at different weight concentrations of 10.0%, 12.5%, and 15.5%, respectively, emit a broadband emission from 400 nm to 900 nm. The EQE values of the pcW-LEDs encapsulated with NIR phosphor at weight concentrations of 10%, 12.5%, and 15.0% are 26%, 23%, and 19%, respectively. The correlated color temperatures of these samples are 5767 K, 5940 K, and 6068 K, respectively. The obtained radiant fluxes of the samples are 26 mW, 22 mW, and 18 mW, respectively, at an injection current of 50 mA. Full article

Academic success in medical education is shaped by a complex interaction of biological predispositions, lifestyle choices, and mental health status. Understanding these factors is essential for student-centered educational reform and well-being support systems. This study investigates the association between biological traits, lifestyle behaviors, psychological stress, and academic outcomes among Vietnamese medical students. A cross-sectional survey of 1227 students from a Vietnamese medical university was conducted, with valid GPA data from 1038 participants. Data on biological (age, sex, BMI, blood group), lifestyle (diet, sleep, exercise, screen time, self-study), stress-related (DASS-21 scores, life domain-specific stressors), and social–academic factors (major, year, roommates) were collected. Linear regression models were applied to explore relationships with GPA. Lifestyle factors (R² = 0.032, p = 0.001) such as eating dinner (p = 0.001), self-study hours (p = 0.005), and having breakfast (p = 0.046) were positively associated with GPA. Biological variables had a smaller impact (R² = 0.013), with age showing a modest positive association (p = 0.001). Mental health scores (DASS-21) explained 1.2% of GPA variance (p = 0.007), with depression positively and stress negatively influencing performance. Academic year was a consistent predictor across models (p = 0.001), and multivariate regression combining all categories (R² = 0.048, p < 0.001) confirmed these relationships. In conclusion, regular mealtime patterns, particularly having breakfast and dinner, and consistent self-study routines are stronger predictors of GPA than biological or general stress markers. Educational institutions should promote healthy daily routines and academic mentoring. Full article

Lightning-induced voltages on overhead distribution lines present a formidable obstacle to ensuring the reliability of power systems, evaluated through conventional numerical techniques, such as the Finite Difference Time Domain (FDTD) method and the Finite Element Time Domain (FETD) method. This study proposes a novel implementation of the Radial Basis Function-Finite Difference Time Domain (RBF-FDTD) method, extending the foundation of our previous work to address the field-to-line coupling equations governing such systems. The effectiveness and accuracy of this approach are rigorously validated through RBF-FDTD numerical simulations, applied to both horizontal and vertical configurations of a 1 km, 110 kV multi-conductor distribution line, as well as a real-world three-phase overhead line in Vietnam. In this study, the impact of various parameters, including line geometry, the presence of ground wires, and the influence of perfectly and imperfectly conducting ground, on the lightning-induced voltages are investigated. The simulation and computational results are in good agreement with findings from prior studies, underscoring the potential of the RBF-FDTD method as a robust tool of practical implications. Full article

Background: Population-specific reference genomes are essential for improving the accuracy and reliability of genomic analyses across diverse human populations. Although Vietnam ranks as the 16th most populous country in the world, with more than 86% of its population identifying as Kinh, studies specifically focusing on the Kinh Vietnamese reference genome remain scarce. Therefore, constructing a Kinh Vietnamese reference genome is valuable in the genetic research of Vietnamese. Methods: In this study, we combined PacBio long-read sequencing and Bionano optical mapping data to generate a de novo assembly of a Kinh Vietnamese genome (VHG), which was subsequently polished using multiple Kinh Vietnamese short-read whole-genome sequences (WGSs). Results: The final assembly, named VHG1.2, comprised 3.22 gigabase pairs of high-quality sequence data, demonstrating high accuracy (QV: 48), completeness (BUSCO: 92%), and continuity (295 super scaffolds, super scaffold N50: 50 Kbp). Using multiple bioinformatic tools for variant calling, we observed significant variants when the population-specific reference VHG1.2 was used compared to the standard reference genome hg38. Conclusions: Overall, our genome assembly demonstrates the advantages of a long-read hybrid sequencing approach for de novo assembly and highlights the benefit of using population-specific reference genomes in population genomic analysis. Full article

This paper explores the energy-saving behavior of hotel guests in the Vietnamese context. We adapted the theory of planned behavior (TPB) and the norm activation model (NAM) to develop a research model with six determinants of energy-saving intention and behavior. A self-administered online survey was implemented to collect data from hotel guests in Hanoi and Quang Ninh provinces. After 4 months, we received 253 valid responses for further analysis. SmartPLS 4.0 software was employed for structured equation model testing. Our findings showed that TPB variables and NAM variables jointly explain the energy-saving intention and energy-saving behavior of Vietnamese hotel guests. Among the three factors of TPB, subjective norms have the most substantial impact on energy-saving intention and a significant direct effect on energy-saving behavior. Meanwhile, awareness of consequences does not significantly affect personal norms, and in turn, personal norms do not directly affect energy-saving behavior. Thus, we proposed several solutions to hotel managers to promote energy-saving initiatives and attract the engagement of their guests in these initiatives. Full article

Coral reefs are well known for their diversity and value, providing habitats for a third of marine species within just 0.2% of the ocean. However, these natural habitats face significant threats and degradation, leading to unresolved issues related to coral loss inventory, coral protection, and the implementation of long-term conservation policies. In this study, we examined two decades of changes in coral spatial distribution within the Nha Trang Bay Marine Protected Area (MPA) using remote sensing and machine learning (ML) approaches. We identified various factors contributing to coral reef loss and analyzed the effectiveness of management policies over the past 20 years. By employing the Light Gradient Boosting Machine (LGBM) and Deep Forest (DF) models on Landsat (2002, κ = 0.83, F₁ = 0.85) and Planet (2016, κ = 0.89, F₁ = 0.82; 2024, κ = 0.92, F₁ = 0.86) images, we achieved high confidence in our inventory of coral changes. Our findings revealed that 191.38 hectares of coral disappeared from Nha Trang Bay MPA between 2002 and 2024. The 8-year period from 2016 to 2024 saw a loss of 66.32 hectares, which is in linear approximation to the 125.06 hectares lost during the 14-year period from 2002 to 2016. It is concluded that the key factors contributing to coral loss include land-use dynamics, global warming, and the impact of starfish. To address these challenges, we propose next a modern community-based management paradigm to enhance the conservation of existing coral reefs and protect potential habitats within Nha Trang Bay MPA. Full article

This paper aims to comprehensively investigate the axial and flexural performance of circularized square reinforced concrete (CSRC) columns discontinuously and continuously confined with carbon fiber-reinforced polymer (CFRP). The test results of twenty reinforced concrete (RC) columns, consisting of twelve CSRC columns and eight square RC (SRC) columns, are presented to compare the axial and flexural performance of discontinuously CFRP-confined CSRC (CFRPC-CSRC) columns with those of continuously CFRPC-CSRC and CFRPC-SRC columns. It was found that to enhance the load-bearing capacity (LBC) of SRC columns, circularizing the SRC columns before applying either discontinuous or continuous FRP confinement was more effective than applying continuous FRP confinement alone. Additionally, the theoretical strength interaction diagrams of test columns were developed using the strip-by-strip method, showing a strong agreement with the experimental results. Full article

This study aims to examine how the collision angle affects the Cu-Ta weld generated by the explosive welding method using molecular dynamics modeling. When two blocks collide, the metallic substrates melt rapidly. Subsequently, when heat energy dissipates to the surrounding areas, the weld interface begins rapidly cooling. Eventually, the weld joint’s surface shape and temperature stabilize. A meta-solid solution state between Cu and Ta could develop under extreme collision conditions of explosive welding through a dynamic diffusion mechanism. Furthermore, the plastic deformation process of the face-centered cubic (FCC) matrix after the explosive collision causes twin boundary scattering in the Cu substrate. The stress evolution experiences three stages: quick increasing, spreading out, and stabling. The stress mainly concentrates on the weld joint. Due to its dynamic recrystallization mechanism, the Cu substrate has a lower residual stress level than the Ta substrate. The atomic strain of the Cu-Ta weld joint improves dramatically as the impact angle increases. The high-strain zone extends toward the lower Ta block between 5° and 15°. Furthermore, the atomic strain and amorphous structure rates increase when the impact angles increase from 5° to 15°. After further improvement up to 20°, they then suffer a decrease. The Cu-Ta weld achieves a tensile strength ranging from 6.37 to 8.94 GPa. The Cu/Cu-Ta/Cu welding joint’s interface is coherent, transforming from an amorphous to a body-centered cubic (BCC) structure. Because of the dynamic diffusion mechanism at the interface, which creates an almost identical atomic rate between Cu and Ta atoms, combined with the dynamic recrystallization phenomenon, explosive welding provides the advantage of combining two low-solubility solid-solution metals. Full article

This study explores the use of propylene oxide-modified ethylenediamine (PPO-EDA) as a novel crosslinker and chain extender in polyurethane (PU) adhesives. PPO-EDA was synthesized and compared with N,N’-dimethylethylenediamine (DMEDA) to assess its impact on mechanical properties and adhesion performance. Key parameters such as NCO conversion, tensile strength, and lap shear strength were thoroughly evaluated. The results demonstrated that incorporating PPO-EDA significantly improved NCO conversion and crosslink density, leading to notable enhancements in tensile strength and elastic modulus compared to DMEDA. Lap shear tests further revealed superior adhesion performance in PPO-EDA-modified PU adhesives, particularly on amine silane-treated steel substrates, where lap shear strength consistently outperformed other samples. This improved performance was attributed to PPO-EDA’s dual role as a chain extender and crosslinker, which strengthened the adhesive’s structural integrity. This study underscores the effectiveness of PPO-EDA as a modifier for enhancing both mechanical and adhesive properties in PU-based adhesives, offering a promising solution for optimizing high-performance adhesives in automotive and industrial applications. Full article

Targeted metabolomics and lipidomics are increasingly utilized in clinical research, providing quantitative and comprehensive assessments of metabolic profiles that underlie physiological and pathological mechanisms. These approaches enable the identification of critical metabolites and metabolic alterations essential for accurate diagnosis and precision treatment. Mass spectrometry, in combination with various separation techniques, offers a highly sensitive and specific platform for implementing targeted metabolomics and lipidomics in clinical settings. Nevertheless, challenges persist in areas such as sample collection, quantification, quality control, and data interpretation. This review summarizes recent advances in targeted metabolomics and lipidomics, emphasizing their applications in clinical research. Advancements, including microsampling, dynamic multiple reaction monitoring, and integration of ion mobility mass spectrometry, are highlighted. Additionally, the review discusses the critical importance of data standardization and harmonization for successful clinical implementation. Full article

Hepatitis B remains a major public health issue in Vietnam. Mandatory reporting to the national electronic communicable disease surveillance system (eCDS) has been required since July 2016. We conducted an evaluation of the hepatitis B surveillance system in Ninh Binh, the province with the highest reported burden of hepatitis B in Northern Vietnam, between 2017 and 2022. Using the CDC’s guidelines for evaluating public health surveillance systems, we assessed four key attributes: simplicity, timeliness, data quality, and acceptability. This retrospective evaluation included document reviews, analysis of hepatitis B data, and in-depth interviews with provincial-level healthcare staff involved in the reporting of hepatitis B cases. The results showed that the eCDS improved reporting frequency, provided more detailed case information, and enhanced data accessibility compared to the previous paper-based system. However, the system faced several challenges, including unclear objectives, difficulties in distinguishing acute from chronic cases, insufficient training for staff, lack of supervision for data quality, and technical software issues. Despite these challenges, stakeholders found the system acceptable but emphasized the need for improvements, including revising the system’s objectives, automating case classification, enhancing training, securing funding for maintenance, and implementing regular data review processes. Full article

During the past two decades, Hue city has undergone significant changes in its economic development, leading to a rapid transformation of its land-use and land-cover (LULC) patterns. This study used remote sensing data and Geographic Information Systems (GIS) to analyze changes in the land-use and land-cover in Hue city, providing essential insights for the city’s future development. This research examines indicators such as area and land-cover changes, urban development trends, and the morphology of urban areas during the period from 2000 to 2020, with assessments conducted at ten-year intervals. The results showed that built-up and forest land have increased, while agricultural and unused land have decreased over time. By 2020, the urban area had expanded by more than 60% in the north and northeast directions. Hue city developed through infilling and edge expansion of existing urban areas, while some regions primarily expanded into outlying sections in the east and south by constructing high-end residential areas on former paddy rice fields. These findings yield valuable policy implications that extend beyond the case study of Hue city, offering insights for other cities to pursue inclusive and prosperous futures. Full article