română EUGENIA TANASĂ
Abstract
One extremely promising method for producing hydrogen sustainably and storing energy is the photoelectrochemical (PEC) splitting of water with solar energy. Hematite is a good photoanode material for water splitting because of its advantageous qualities, according to recent study in this area: it is an n-type semiconductor, possesses a band gap appropriate for visible light absorption, exhibits high chemical stability, and is abundantly available on Earth. This review presents various strategies for modifying hematite to enhance its performance. These modifications include element doping, nanostructure design and fabrication, co-catalyst integration, heterostructure formation and the interdependence between the structure and performance of hematite.
Keywords
solar energy, hematite, photoanoes
XIANWU JING, XIAOJIN ZHOU, TENG GONG, TAO WANG, YANG WANG, GUOQING LIU, KAIJUN WANG
Abstract
This research employed molecular dynamics simulations to explore the distribution of sodium dodecyl sulfate (SDS) at the n-hexane/water interface. Once the SDS concentration surpasses the critical micelle concentration(cmc), a large portion of SDS migrates to the n-hexane/water interface, establishing a thin layer where sulfonic acid groups are oriented towards the water phase and carbon-hydrogen chains are directed towards n-hexane, a small amount of SDS forms spherical micelle with sulfonic acid groups facing the water phase, while carbon-hydrogen chains aggregate in the interior of these spherical structures. The sulfonic acid group of SDS forms multiple h-bonds with water, shows strong interaction energy; while the carbon hydrogen chain itself has only weak van der Waals interactions with surrounding molecules. The thickness of SDS- layer at the n-hexane/water interface is about 2.06 nm, with a maximum number density of about 0.25 per nm3, and average area occupied by a single SDS- is about 0.21 nm2. According to radial distribution function (RDF) result, due to the attractive effect of positive and negative charges, the first coordination layer of Na+ ions and oxygen atoms on sulfonic acid groups is about 0.21 nm. This study investigated the distribution of SDS at n-hexane/water interface, vividly demonstrating the mechanism by which SDS reduces the interfacial tension between oil and water, and providing guidance for oilfield development.
Keywords
N-hexane/water interface; Molecular dynamic simulation; Sodium dodecyl sulfate; Weak interaction analysis
ZHI LI, PING JIANG
Abstract
To address the performance limitations of single silica (SiO2) encapsulated phase change materials, a novel shape-stable composite microencapsulated phase change material (CA/CS/SiO2 MEPCM) was prepared using the sol-gel method. Capric acid (CA) was used as the phase change material (PCM), while chitosan/silica (CS/SiO2) served as the composite encapsulation material. Fourier transform near infrared spectroscopy (FT-NIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were employed to characterize the chemical structure, crystalline phase, and microstructure of the CA/CS/SiO2 MEPCM. The thermal storage properties and thermal stability of the MEPCM were analyzed using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). SEM results indicated that CA was effectively encapsulated within the CS/SiO2 shell, and the reticulated structure of the shell contributed to the high shape stability of the MEPCM. The results demonstrate that CA is effectively encapsulated within the CS/SiO2 shell, and the network structure of the shell significantly enhances the shape stability of the MEPCM. The encapsulation process preserves the chemical integrity of CA, as no structural changes were observed. The synthesized MEPCM exhibits excellent sealing performance at 102 °C, and the thermal stability of the CS/SiO2 composite shell surpasses that of conventional single-shell structures. Furthermore, the material displays a moderate phase transition temperature and a maximum latent heat of 69.38 J/g, meeting the requirements for variable thermal regulation. In conclusion, the CA/CS/SiO2 MEPCM developed in this study is a green, non-toxic, and structurally stable phase change material with a tunable phase transition temperature, offering promising potential for sustainable thermal energy storage applications.
Keywords
capric acid, chitosan, silicon dioxide, microencapsulated phase change materials
VISWANATH KRISHNAN, MOHAN EKAMBARAM, VINOTHKUMAR RAVI, SHEEBA RANI SOUNDARAPANDIAN
Abstract
In this study, powdered magnesium and aluminum particles were combined with a smaller quantity of silicon carbide (SiC) particles, and the sintering process was used to form the metal matrix composite (MMC). The specimens were made at three distinct temperatures such as 4500C, 5000C, and 5400C. The addition of silicon carbide to the magnesium and aluminium leads to increase the hardness. Based on the scanning electron microscopy (SEM), a large number of holes were commensurate with the sintered specimen produced at the minimal sintering temperature. The development of pore was significantly reduced at high temperature, and strong metallurgical bonding was also attained. The hardness of the sintered specimen was also raised at high sintering temperatures. When compared to other traditional machining methods, the reason for using spark erosion machining or electric discharge machining (EDM) is to maintain the optimal surface roughness (SR) and increase material removal rate (MRR). An atomic force microscopy (AFM) and SEM examination was carried out specifically to evaluate the surface parameters of the magnalium MMC. The pit and valley surface was observed in the machining surface. Current and voltage played a crucial role in metal removal and surface roughness.
Keywords
Magnalium composite, sintering, powder metallurgy, hardness, spark erosion machining
QIAN HONG, XIAOFENG CHEN, WEIQING YU, XIAOXIAO MA, YANBING WANG, CHONGQING WANG, CHAO LIU
Abstract
Faced with the defects of engineering disturbed slope soil, such as easy erosion and evaporation of water, this paper uses polyvinyl alcohol (PVA) hydrogel as a soil conditioner to improve the water erosion resistance and water retention performance of engineering disturbed slope soil, and studies the vegetation performance and microstructure of modified soil. The results showed that PVA hydrogel changed the soil structure by using its excellent cementation and water holding capacity. PVA hydrogel completely wrapped the soil particles to form the overall structure of network gel, which significantly improved the soil erosion resistance, water stability and water retention capacity of the soil. With the increase of PVA concentration, the soil erosion resistance, water stability and water retention performance are significantly improved. In addition, the effect of increasing PVA concentration on soil vegetation performance shows a trend of first strengthening and then weakening, with the best soil vegetation performance observed when PVA concentration was 3%. The results show that PVA hydrogel has important application value for reducing soil and water loss of engineering disturbed slope and promoting vegetation restoration.
Keywords
disturbed slope, ecological restoration, erosion resistance, water retention performance, vegetation performance
PREPARATION METHOD OF DIATOM-BASED EARTH AND ZINC OXIDE COMPOSITE HIGH-DENSITY POLYETHYLENE MATERIAL
KUN LU, HAN KONG, YAOWEN ZHANG, JIAXING ZHU, YUANYUAN DING, XIYU HUANG, CHAO ZHANG
Abstract
In order to cope with the increasingly severe environmental nanotechnology problems and energy shortage, the development of green new materials has become an inevitable trend in today society. In this paper, a preparation method and application of diatom-based earth and zinc oxide composite high-density polyethylene material are provided, which belong to the solid adsorbent composition material. Firstly, high-density polyethylene composites were prepared according to a certain proportion of diatom-based earth and zinc oxide and polyethylene. Then, to improve its performance and UV resistance, Tinuvin 770 is added and mixed with a composite polyethylene material in a gear mixer. Subsequently, the twin-screw extruding machine is set to a certain temperature and speed, extruded, and the extrusion is cut into composite pellets using a tray machine. Finally, these composite pellets are injected into the injection molding machine, where the target mold is selected and molded. At the same time, it can be used as a food packaging bag material, which can inhibit the growth of Staphylococcus aureus and E. bacillus, so that it has the minimum UV stabilizer content, which is a cost-effective and high-performance choice, and its ability to block ultraviolet rays is strong, and it can well protect the quality of packaged food.
Keywords
diatom-based, Zinc Oxide, High-Density polyethylene, Tinuvin 770
IOANA ION, CIPRIAN MIHAI MITU, EMANUEL VIRGIL MARINESCU, ANDREI CUCOS, ALINA RUXANDRA CARAMITU
Abstract
This study presents an eco-friendly synthesis route for a novel hybrid hydrogel (HHy) designed for wastewater remediation using dual crosslinking method: freezing–thawing (FT) and gamma irradiation (GIrr). Polyvinyl alcohol (PVA) and carboxymethyl cellulose (CMC) form the polymeric matrix, silver nanoparticles (AgNPs), and AgNPs decorated graphene oxide (AgNPs/GO) are incorporated to enhance adsorption and photocatalytic properties. Methylene blue (MB) dye was employed as a model pollutant to assess improved adsorption performance. The HHy demonstrated significant improvements compared to unmodified Hy for equilibrium adsorption capacity (EAC): 20% increase with HyAgNPs and 130% for HyAgNPs/GO; swelling ratio (SWR) measurement revealed an increase of 6% for HyAgNPs, 109% for HyAgNPs/GO; water content (WCR) had an increase of 1 % for HyAgNPs, 14 % for HyAgNPs/GO compared to unmodified Hy. Thermal analysis revealed that total carbonaceous residue after pyrolysis at 800 ⁰C, reached approximately 20% of the Hy’s mass for HyAg and HyAgNPs/GO. This indicates effective char formation due to the catalytic role of the AgNPs and graphene oxide (GO) as nucleation sites. The study optimizes the design of functional Hy for water treatment, and also proposes a viable end-of-life strategy through controlled pyrolysis. The synergistic effects of CMC, graphene oxide (GO), and AgNPs enhance both the structural and functional performance of the HHy system, positioning this approach as a promising avenue for advanced wastewater treatment technologies.
Keywords
wastewater remediation, hybrid hydrogel, silver nanoparticles, graphene oxide, graphene oxide decorated with silver nanoparticles, methylene blue adsorption
WEI ZHENG
Abstract
This work presents an optoelectronic study of cobalt-doped nano-TiO2 camouflage films prepared via a non-hydrolytic sol–gel route and examines their suitability for device integration. Photoluminescence (PL) and UV–Vis absorption measurements show that the films possess a tunable bandgap (3.12–3.24 eV) and exhibit a rapid photoconductive response under visible illumination, with a rise time of about 15 ms and a decay time of roughly 25 ms. SEM observations indicate a highly uniform film morphology, and UV aging tests verify that the coatings retain their structural and optical stability in ambient conditions. When these materials are incorporated into prototype thin-film photodetectors, the devices achieve an on/off photocurrent ratio exceeding 10³ and a responsivity of 0.15 A/W at 450 nm, pointing to their practical promise for adaptive optical filters and smart window coatings. In addition, assessment of visual performance shows that nanoscale optical camouflage layers deliver an average increase of 0.91 points in visual impact over conventional materials, underscoring the capacity of nanoscale optical and electronic architectures to reshape graphic design by enabling more dynamic and aesthetically compelling visual experiences.
Keywords
Nanoscale Optical Camouflage Materials, Electronic and Optoelectronic Properties, Nano Titanium Dioxide, Graphic Design Enhancement, Sol-Gel Process
CHUFENG TAO
Abstract
A novel nanoscale optoelectronic imaging platform is presented that leverages quantum-dot–sensitized sensors together with a hybrid clustering strategy to realize ultra-high-speed acquisition and analysis of rapid nanoscale phenomena. By embedding CdSe/ZnS quantum dots into a plasmonic imaging circuit and feeding the sensor output into a modified k-means routine steered by an artificial fish swarm algorithm (AFSA), data redundancy is suppressed and representative keyframes are extracted in real time. Experiments tracking plasmonic nanoparticle motion under pulsed excitation show a 9.96 % rise in clustering accuracy and a 7.44 % increase in recall relative to standard k-means, accompanied by a 0.086 improvement in the silhouette coefficient. Collectively, these results demonstrate concurrent gains in spatial resolution (down to 50 nm) and temporal resolution (sub-microsecond). Demonstrations in in-situ nanomanufacturing quality monitoring and single-molecule bioimaging further illustrate the platform’s applicability across nanoelectronics and optoelectronic systems.
Keywords
Nanoscale Optoelectronics, Ultra-High-Speed Optical Imaging, Nanomaterials in Imaging Technology, Image Processing Algorithms, High-Speed Phenomena Analysis
ELENA CHIȚANU, MIRELA MARIA CODESCU, VIRGIL MARINESCU, ISTVAN BORBÁTH
Abstract
Nanomaterials have attracted considerable attention due to their flexible synthesis methods and wide-ranging functional applications. Among these, SiO2 nanoparticles have attracted significant attention owing to their controllable physicochemical properties, which can be precisely engineered for specific biomedical applications. Since its introduction in 1968, the Stöber method—despite undergoing only minor refinements—has remained the most widely adopted approach for the synthesis of nanoscale SiO2. Due to their morphology and particle size, SiO2 nanoparticles are particularly suitable for use in advanced manufacturing techniques such as three-dimensional (3D) printing, especially within biomedical engineering applications, including bone tissue regeneration. In such contexts, SiO2 nanoparticles are typically dispersed in suspensions, where knowledge of their surface charge is essential, as it plays a critical role in governing their aggregation and colloidal stability. However, existing measurement techniques do not permit direct and accurate quantification of surface charge; consequently, this parameter is often indirectly estimated through the determination of zeta potential. This study presents the tetraethyl orthosilicate (TEOS) concentrations influence on the stability of the SiO2 suspensions. The SiO2 nanoparticles were prepared by classic Stöber technique, with spherical uniform geometry and average sizes starting from 152 nm up to 681 nm due to increasing concentration of TEOS. To determine the zeta potential, suspensions containing 0.05 wt.% SiO2 were prepared in solutions with pH values ranging from 1 to 12. Under alkaline conditions (pH 12), the smallest SiO2 nanoparticles exhibited zeta potential values of up to −58.4 mV, indicating that the analysed suspensions were stable in this medium.
Keywords
silica 3D printing, Stöber method, suspensions stability, zeta potential
KARTHIKEYAN SAMBANDHAM, BASKAR NEELAKANDAN, GANESAN MANICKAM, RAMKUMAR KATHALINGAM
Abstract
Friction welding is an efficient and economical process of joining two similar or dissimilar metals among various welding processes. Now-a-days, the automobile and other industries are using dissimilar metals in a same working area to compensate the problems faced due to temperature and working atmosphere to enhance company’s economy. The material AA6351 and EN353 alloy steel have wide applications in aerospace & automobile industries, are joined with different input parameters like Heating Time (HT), Heating Pressure (HP), Upset Time (UT), Upset Pressure (UP) with constant rotation. These input parameters are ordered using L27 Taguchi Orthogonal Array (OA) to experiment the process. Friction welding is done in KUKA friction welding machine. After experimentation, the responses like temperature, hardness and axial shortening are measured. Using these responses, the optimization is carried out through Grey Relational Analysis (GRA) and the rankings are identified and tabulated to obtain the optimal solutions. Based on rankings, the optimal input parameters are concluded as 18 bar of Heating Pressure (HP), 7 sec of Heating Time (HT), 22 bar of Upset Pressure (UP) and 3 sec of Upset Time (UT). The Field Emission Scanning Electron Microscope (FESEM) analysis is also used to study the Inter-metallic compounds (IMCs).
Keywords
Friction Welding, AA6351, EN353, Grey Relational Analysis, FESEM analysis
GUIZHEN WANG, LINGLONG ZHOU
Abstract
This study explores the seismic reinforcement of coastal buildings through the innovative application of Shape Memory Alloys (SMAs). SMAs, a novel class of functional materials, exhibit unique properties like shape memory effect, superelasticity, and high damping performance, making them ideal for seismic applications. Recognizing the critical role of structural design in a buildings earthquake resistance, this research introduces an SMA-based damper specifically tailored for coastal structures, considering their unique stress profiles and disaster vulnerability. Through experimental and simulation methods, including MATLABs Simulink module, the study compares the seismic responses of conventional coastal building designs with those incorporating the SMA damper. The results reveal that the SMA dampers bilinear restoring force mechanism significantly enhances vibration suppression, offering a promising solution for seismic reinforcement in building construction. This investigation not only contributes to the understanding of SMA materials but also underscores their potential in structural earthquake resilience, marking a significant intersection of material science, engineering, and seismic technology.
Keywords
Shape Memory Alloys (SMAs); Seismic Dampers; Coastal Building Reinforcement; Earthquake Resistant Structures; Superelastic Materials