This study evaluates the effect of Calcium carbonate (CaCO₃) on the mechanical properties and structure of SEBS-compatible PA6/ABS composites. Composites consisting of 50/50 PA6/ABS, 5% SEBS, and 0–20% by weight CaCO₃ were fabricated by injection molding. Tensile and flexural strengths were determined according to ISO 527-2:2012 and ISO 178:2019, respectively. The tensile strength increased with filler content, peaking at 15 wt% CaCO₃ (24.72 MPa), while flexural strength reached a maximum at 10 wt% (32.51 N/mm2). FESEM revealed a uniform dispersion of CaCO₃ particles and strong interfacial adhesion at optimal filler contents, whereas agglomeration and microvoids occurred at higher loadings. The results demonstrate that moderate CaCO₃ addition enhances stiffness and strength through effective stress transfer, while excessive loading induces brittleness due to poor interfacial bonding. This study contributes to the optimization of hybrid polymer composites for structural, automotive and precision engineering

Silicene nanoribbons (SiNRs), as one-dimensional derivatives of silicene, exhibit highly anisotropic charge transport and hold significant promise for future nanoelectronics applications. In this work, we systematically investigate the structural stability and electronic properties of hydrogen-passivated SiNRs doped with aluminum using first-principles density functional theory calculations performed with the VASP package. Several possible Al substitutional doping configurations are examined, among which three representative geometries-top, valley, and 1-1 arrangements-are identified as energetically stable, while other configurations undergo severe structural distortions or bond breaking during structural relaxation. Formation energy analysis indicates that the 1-1 alloy configuration is the most thermodynamically favorable due to the symmetric distribution of Al dopants and a balanced local bonding environment. Electronic structure calculations reveal that pristine hydrogenated SiNRs are narrow-gap semiconductors with a band gap of approximately 0.325 eV, whereas all stable Al-doped systems undergo a transition to semi-metallic behavior. This electronic transformation originates from the incorporation of group-III aluminum atoms, which introduce hole carriers and shift the Fermi level, leading to enhanced electrical conductivity. In addition, the tunability of the electronic properties is further explored under a constant external electric field of 0.15 eV/Å, demonstrating additional control over the electronic response of the doped nanoribbons. These results highlight aluminum doping, in combination with external electric-field modulation, as an effective strategy for tailoring the electronic characteristics of silicene nanoribbons and suggest promising opportunities for the design of low-dimensional materials with controllable transport properties for advanced nanoelectronics and optoelectronic applications.

Proton exchange membrane fuel cells (PEMFCs) have attracted significant attention due to their high efficiency and low emission characteristics. However, the cell performance is strongly influenced by operating conditions and membrane properties, which are difficult to investigate comprehensively by experimental approaches alone. This study develops a complete electrochemical model of a single PEM fuel cell in the MATLAB – Simulink environment based on the voltage loss mechanisms including the Nernst potential, activation overpotential, ohmic losses, and concentration losses. The model is employed to quantitatively investigate the effects of operating temperature, hydrogen partial pressure, oxygen partial pressure, and membrane thickness on the polarization characteristics (I – V curves) of the PEMFC. Simulation results indicate that increasing temperature significantly enhances activation kinetics and improves cell voltage, while elevated oxygen partial pressure yields the most pronounced performance improvement among gas parameters. Conversely, increasing membrane thickness leads to higher ohmic losses and voltage degradation, especially in the high –current – density regime. The proposed model provides an effective numerical tool for teaching, system analysis, and preliminary optimization of PEMFC operating conditions.

In recent years, water hyacinth (Eichhornia crassipes) has been widely recognized as an invasive aquatic plant that proliferates rapidly on rivers, canals, ponds, and lakes, obstructing waterway transportation, impeding water flow, and contributing to environmental degradation. Despite its abundance in large river systems such as the Bach Dang River in Thu Dau Mot City, Binh Duong Province, this biomass resource remains largely underutilized, leading to significant waste of natural materials and ongoing ecological challenges. This study proposes an eco-friendly alternative by transforming water hyacinth into handmade paper sheets with natural coloration, rustic aesthetic, and complete absence of harmful chemicals. The resulting products exhibit acceptable strength and surface quality, making them suitable for practical and decorative applications including coasters, shoe insoles, greeting cards, notebooks, biodegradable packaging, paper bags, and eco-handicraft items. Raw materials were collected directly from the Bach Dang River by a student research group. The research employed a combination of primary and secondary data collection methods, along with experimental, analytical, and synthesis approaches to develop and evaluate the manual paper-making process. The developed chemical-free production method successfully yielded durable paper sheets that are environmentally safe and biodegradable. The findings demonstrate the feasibility of converting an invasive plant into value-added sustainable products, thereby contributing to waste reduction, biomass reuse, and the promotion of green production practices. Although the study is preliminary and limited by manual processing, lack of mechanization, and absence of standardized quantitative testing (e.g., tensile strength, water absorption, and biodegradability under controlled conditions), it provides a promising foundation for further optimization and scale-up. Future research should focus on improving uniformity, enhancing mechanical properties through natural additives, and conducting comprehensive performance and life-cycle assessments to support practical commercialization and broader environmental impact

In this paper, we consider a boundary value problem involving the Hadamard fractional derivative. We establish a Lyapunov-type inequality for the problem by constructing the green function and analyzing its properties. Next, we employ a fixed-point theorem to obtain the existence and uniqueness of the solution to the problem. The paper concludes with three examples that illustrate the theoretical results.

Based on existing knowledge about Kronecker product of two matrices and matrix operations such as multiplying two matrices, computing the determinant of a square matrix and finding the inverse of a square matrix, the article clarifies the concept of Kronecker product of two matrices and some of its properties are related to matrix operations known above. The article will also present the application of Kronecker product in large-order matrix operations such as multiplying two matrices, computing the determinant of a square matrix and finding the inverse of a square matrix with specific illustrative examples. Applying Kronecker product in those matrix operations known above will significantly reduce the amount of calculation.

In electronic circuits that use various integrated circuits (ICs), ICs may malfunction while assembled, used, and repaired. There are numerous ways to verify that ICs are operating, such as by measuring basic current and voltage with a VOM meter. However, many sophisticated operations are hard to measure and test, and the accuracy of the tests is low and takes a long time. Thus, it is crucial to have a tool that can rapidly determine whether or not integrated circuits are operating correctly. The purpose of this article is to develop a tool for testing the functionality of logic gate ICs. By modeling its properties using the truth table of the specific IC, the device employs an Arduino to verify the condition of the gates in a logic gate IC. After successful simulation and testing, they are assembled to form a final device.

The theory of differential equations arises from the study of physical phenomena. This field has various applications in science and engineering. The study of qualitative properties for each mathematical model plays an important role, attracting the attention of both theoretical and applied researchers. Normally, the most significant qualitative property to be studied first is the existence and uniqueness of the solutions of each mathematical model. However, proving existence and uniqueness results for mathematical models where the source function has a singularity is a difficult problem and requires many different techniques. In this paper, we establish some new conditions suitable to achieve the unique solution criterion for ordinary first-order differential equations. To obtain the desired results, we have improved the methods that have been used to prove the results in the work of Krasnosel'skii and Krein (Krasnoselskii and Krein, 1956). In addition, we also provide an example to illustrate the theoretical results.

In this study, molecular dynamics simulations were employed to investigate the influence of pressure on the structural properties of silver (Ag) at 300K. The results reveal that an increase in pressure leads to a reduction in nearest-neighbor distance, a promotion of local ordering, and a transition from a largely disordered state to a predominantly face-centered cubic FCC crystalline structure. At intermediate pressures, both hexagonal close-packed HCP and body-centered cubic BCC phases are observed; however, these phases diminish as pressure rises, with FCC becoming the prevailing phase at higher pressures. These findings demonstrate that pressure is a key factor in driving phase transitions and improving crystallinity in metallic systems.

The structural and electronic properties of sulfur-doped armchair stanene nanoribbons (ASnNRs) have been investigated using Density Functional Theory (DFT). The diverse structural and electronic characteristics induced by the substitution of sulfur atoms were comprehensively analyzed through first-principles calculations, including formation energy, optimized structural parameters, projected density of states (PDOS), and spatial charge density distribution. Various doping configurations were considered by replacing Sn atoms with S at different concentrations and atomic positions, resulting in characteristic doping types such as single-atom doping (top-1S, valley-1S), two-atom doping (ortho, meta, para), and full 1:1 substitution with a 6Sn–6S structure. The results reveal significant changes in the bandgap, increasing slightly from 0.26eV in the pristine state to approximately 0.34eV in the meta configuration, moderately decreasing to 0.15eV in the 100% substitution case, and sharply decreasing in the other configurations. Moreover, most sulfur-doped configurations exhibit non-magnetic behavior similar to pristine ASnNRs, while strong magnetism emerges only in the fully substituted 100% case. These findings demonstrate that sulfur doping can fundamentally modify the electronic and magnetic properties of the material, highlighting its potential application in future spintronic devices.

The excellent flexibility of graphene materials that allows them to adjust to the curvature of the substrate surface, chemical surface inertness, and impermeability have attracted considerable attention in the past decade as a blending material and an additive in anti-corrosion coatings. In this paper, we present the role of graphene in enhancing the protective properties of anti-corrosion coatings on metal surfaces with the aim of improving the anti-corrosion performance and extending the life of the coating on metal structures, comparing the anti-corrosion ability of graphene with some types of metal oxide materials such as zinc oxide, titanium dioxide. The methods of graphene fabrication and the method of blending graphene into the coating composition give results on mechanical properties, wettability, antibacterial properties, anti-corrosion properties, fire resistance and current research trends in graphene-based coating materials and explore optimal solutions for applications in the paint industry.

In recent years, asymmetric gold nanoparticles have attracted a lot of attention from researchers owing to their unique properties and varied applications in many fields. In this study, gold nanobranches were prepared using a one-step, green reducing method, with the HEPES buffer acting as both a reducing agent and surfactant. The formation of gold nanoparticles was evaluated using UV-Vis spectroscopy by controlling several practical factors, including the volume of gold salt precursor, the concentration of HEPES buffer, and the solution pH. The morphologies and crystallization of the gold nanobranches were characterized by Scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results indicated that under the optimal synthesis conditions, namely 250 µL of 5 mM HAuCl₄, 0.10 M HEPES, and a pH of 7.5, most of the gold particles in the colloidal solution exhibited multiple branches, with an average size ranging from 20 to 35 nm and high crystal density. This study presented a simple synthesis method utilizing eco-friendly substances to replace conventional reducing agents, contributing to the sustainable development of nanotechnology.

Phyllanthus (Euphorbiaceae) is widely distributed in tropical and subtropical areas, including Vietnam, where it is considered a valuable medicinal herb. Numerous bioactive compounds from Phyllanthus species have been identified, demonstrating pharmacological effects such as antiallergic, anti-inflammatory, antioxidant, antidiabetic, anticancer, antiviral, antibacterial, antimalarial, and wound healing activities. This review provides a comprehensive summary of Phyllanthus genus and its pharmaceutical properties, emphasizing the methodologies used for bioactive compound extraction and evaluation, as well as their clinical relevance.

The paper presents the results of a study on the essential physical properties of armchair SiSn nanoribbon (SiSnNR) material, based on density functional theory (DFT) using the quantum simulation program VASP. Structural parameters are highlighted along with electronic and optical properties. The findings reveal that SiSnNR exhibits significant differences in bond lengths, bond angles, and buckling compared to SiNR and SnNR. SiSnNR demonstrates semiconducting properties, with a direct band gap width of approximately 0.3123Å calculated using GGA-PBE, increasing to 0.5892Å when using the hybrid HSE06 functional. The results indicate that Sn atoms primarily contribute to energy bands below the Fermi level, while Si atoms contribute more to higher energy levels. The study also highlights the overlap of py and pz orbitals, leading to sp2 and sp3 hybridization. In terms of optical properties, the energy range from 3 to 5eV is where SiSnNR exhibits the strongest light absorption. The largest number of electron-hole pairs is generated within the energy range of 8-10eV, resulting in intense optical absorption and transitions in this region.

This study investigates the structural and electronic properties of Au-doped silicene nanoribbons (SiNRs) under the influence of an external electric field of 0.4 eV/Å, utilizing density functional theory (DFT). The stability and structural integrity of SiNRs following Au doping are assessed, considering two distinct doping configurations: the top configuration and the valley configuration, where each unit cell incorporates a single Au atom. The formation energies of the doped systems are calculated to evaluate their thermodynamic stability based on DFT principles. Furthermore, detailed analyses of the density of states (DOS) and energy band structures are conducted. Both doping configurations exhibit metallic characteristics, indicating potential applicability in future nanoelectronic devices.

Improving and exploring the photocatalytic performance of composites for new models continues to pose a challenge. Here, a straightforward thermal dispersion method is achieved by incorporating nitrogen (N) into TiO2 at different weights (1%, 3%, and 5%) to enhance photocatalytic activity. The material properties are analyzed through ultraviolet-visible diffuse reflectance spectroscopy (UV-VIS DRS), and X-ray diffraction (XRD). The results indicate that the NO gas removal efficiency of N-TiO2 photocatalytic materials is higher than that of pure TiO2 after 30 minutes of exposure to visible light. The highest NO gas treatment efficiency of N-TiO2 -1% is 40.4%, with a reaction rate following a first-order kinetic equation of 0.0688 min-1. Successfully fabricating N-TiO2 photocatalytic materials using the thermal dispersion method, with significantly enhanced photocatalytic performance under visible light activation, will benefit practical applications, particularly in the environmental sector.

The cold gas dynamic spraying (CGDS) method enables the application of coatings with various functional properties to nearly any substrate material, facilitates the restoration of geometric dimensions of parts damaged during use, and allows for the renewal of protective anticorrosive coatings without the need for complex structural dismantling. This review describes the latest developments in the processes and applications of CGDS technology.The ease and manufacturability of the process, along with the mobility of CGDS coating systems, make it suitable for use both in industrial settings with robotic systems and in "field" environments.

In this paper, the structural properties of crystalline and polycrystalline Cr have been investigated using molecular dynamics simulations. The interaction between atoms is modeled via the MEAM potential. Periodic boundary conditions are applied in the x, y, and z directions. The structural characteristics are analyzed through the total energy function, heat capacity, radial distribution function, and angle distribution. Dynamics are evaluated through the analysis of mean squared displacement and diffusion coefficient. The results show that the melting temperature of crystalline Cr is higher than that of polycrystalline Cr, indicating that the polycrystal melts earlier. This information is important when considering material applications in high-temperature environments.

ABSTRACT Cooking oil is an indispensable ingredient in everyday family cooking. The oil after use is often discharged directly into wastewater systems, leading to risks of environmental pollution, water pollution, clogging of drainage systems... In recent years, water hyacinth plants have been considered weeds, floating on rivers, canals, ponds and lakes, obstructing the circulation of boats and preventing water flow. Water hyacinth plants are often found in large rivers and almost no one cares about their uses, making them truly wasteful. Realizing the flexibility of water hyacinth when dried, it can be woven into pieces with good absorbent properties, our team has researched using water hyacinth as a material to absorb used cooking oil that is discarded into the environment. school. The research uses the main methods of experimental method and sample analysis method in its research. The result is that a product that absorbs discarded cooking oil scum is formed and is tested for cooking oil contaminated water with results consistent with QCVN 14:2008/BTNMT. The purpose of the research is to find effective products to absorb discarded cooking oil to save costs and contribute to environmental protection. The problem of using naturally available materials to create products that absorb cooking oil scum at the same time solves two current environmental problems. The research is a preliminary result, so there are still many shortcomings. We hope that in the future there will be further research to make the product more and more perfect

Advanced materials have been of interest in recent years because of their outstanding properties that bring many useful applications to humans, they can be highly compatible with alternative materials. In particular, coating materials on HAp base increase the biocompatibility of HAp. In this study, we synthesize TiO2/HAp composite materials using the sol - gel method. Samples were made under different synthesis conditions in terms of HAp/TTIP ratios: (1:1); (1:1.5); (1:2); (1:2.5); (1:3). Factors affecting the synthesis process, such as the incubation time and pH of the solution, were also investigated. The optimal conditions for the synthesis process are the ratio HAp/TTIP: 1 gram HAp with 2 ml TTIP; stirring time: 16 hours; pH of the gel solution: pH = 0.5, as determined from the analysis of the X-ray diffraction spectrum and SEM surface morphology. The research results are the basis for research on biomedical materials.

Investigating the characteristics of the three-step sorption of Sc on armchair silicene nanoribbons is the aim of this study. Since absorbed energy is the largest of the bridge, hollow, valley, and top positions, the hollow position is selected first. The structural state of the second step has an energy of adsorption of 4.18 Å and a bond length of 2.36 Å for Si-Si. Finally, ASiNRs with a high Sc atom had their 1.25 Å surface modified. Adsorbed ASiNRs resulted in new materials with semi-metal and magnetic characteristics, suggesting potential use in spintronic and electronic devices in the future.

In this work, we focus on investigating ill-posed problems (according to the definition given by Hadamard) in the topic of its application. Specifically, we present some theories about the properties of the ill-posed problem in image processing. By using discrete Fourier transform and fast Fourier transform methods, we present several results on image processing topic. Finally, some illustrative examples are presented through algorithms running on Python software.

In the paper, we investigate the structure and electronic properties of the pristine germanene nanoribbon and four adsorption configurations of 1F and 2F on the substrate of germanene nanoribbon. We obtained the parameters of the most stable structures of pristine germanene nanoribbon and four adsorption configurations. The band structure and the density of state and the part density of state for each element were also obtained. Findings show the adsorption configuration of 1F-GeNR.bridge has no band structure, while other configurations are semimetals with band gap from 0.175eV to 0.67eV; both four adsorption configurations are chemisorption and non-magnetic. The charge distribution of all configurations also was investigated; it showed that there is a charge shift from Ge atoms towards F atoms due to their electronegativity difference.

Abstract: The article is based on data from the research program "Greater Mekong Subregion Flood and Drought Risk Management and Mitigation Project (ADB-GMS1)" jointly implemented by the Asian Development Bank (ADB) and the Ministry of Agriculture and Rural Development, and the Vietnam Institute of Water Resourches Research in Tien Giang and Dong Thap province. The results show that, in recent years, due to the increasingly severe global climate change, the intensity of various types of natural disasters occurs more frequently, irregularly and with greater intensity. This has greatly affected the production, daily life and properties of the people in the vulnerable areas. To reduce the impact of various types of disasters on people living in vulnerable areas, it is necessary to combine two types of solutions in disaster prevention, namely construction solutions and non- construction solutions. In which, non-construction solutions play a very important role, namely, people living in communities are considered as the main actors in preventing and mitigating disaster risks occurring in the community.