Explore the vast range of titles available.

The purpose of this study was to investigate the relationship between the chemical form and localization of zinc (Zn) in plant leaves and their Zn accumulation capacity. An interspecific cross between Arabidopsis halleri sp. halleri and Arabidopsis lyrata sp. petrea segregating for Zn accumulation was used. Zinc (Zn) speciation and Zn distribution in the leaves of the parent plants and of selected F1 and F2 progenies were investigated by spectroscopic and microscopic techniques and chemical analyses. A correlation was observed between the proportion of Zn being in octahedral coordination complexed to organic acids and free in solution (Zn–OAs + Znaq) and Zn content in the leaves. This pool varied between 40% and 80% of total leaf Zn depending on the plant studied. Elemental mapping of the leaves revealed different Zn partitioning between the veins and the leaf tissue. The vein: tissue fluorescence ratio was negatively correlated with Zn accumulation. The higher proportion of Zn–OAs + Znaq and the depletion of the veins in the stronger accumulators are attributed to a higher xylem unloading and vacuolar sequestration in the leaf cells. Elemental distributions in the trichomes were also investigated, and results support the role of carboxyl and/or hydroxyl groups as major Zn ligands in these cells.

In this work, Friction Stir Welding process was done on the dissimilar alloys AA8014 and AA2024, with focus on analysing mechanical properties such as tensile strength (UTS), hardness (BHN), and wear rate (WRT). The influence of SiC/TiB2 nanoparticles, with Wt% ranging from 2 to 8 wt%, was examined on the mechanical properties. The rotational speed (RS) was changed from 1200 rpm to 1400 rpm, while the welding speed was kept at a constant 150 mm/min throughout the process. The results specified that an increase in RS to 1400 rpm, combined with 8 wt% , improved the ultimate UTS to 239.4 MPa. SEM examination of the fractured surface revealed that micro dimples were produced at this higher rotational speed. This phenomenon is attributed to the more intense stirring action at 1400 rpm, which leads to turbulent material flow in the stir zone. The resulting turbulence could cause uneven particle distribution and entrap air or other voids, contributing to the formation of micro dimples in the weld nugget.

Background and objectives: wear and corrosion can lead to the gross failure of the Morse taper junction with the consequent fracture of the true neck of the prosthetic stem in hip arthroplasty. Materials and Methods: 58-year-old male patient, with a BMI of 38 kg/m2. Because of avascular necrosis, in 2007, a metal-on-metal total hip arthroplasty was implanted in him, with a TMZF stem and a Co-Cr head. In December 2020, he complained of acute left hip pain associated with the deterioration of his left leg and total functional impairment, preceded by the crunching of the hip. X-rays and CT scan showed a fracture of the prosthetic neck that necessitated prosthetic revision surgery. A Scanning Electron Microscope (SEM) analysis of the retrieved prosthetic components was conducted. Results: Macroscopically, the trunnion showed a typical bird beak appearance, due to a massive material loss of about half of its volume. The gross material loss apparently due to abrasion extended beyond the trunnion to the point of failure on the true neck about half a centimeter distal from the taper. SEM analysis demonstrated fatigue rupture modes, and the crack began close to the neck’s surface. On the lateral surface, several scratches were found, suggesting an intense wear that could be due to abrasion. Conclusions: The analysis we conducted on the explanted THA showed a ductile rupture, began close to the upper surface of the prosthetic neck where the presence of many scratches had concentrated stresses and led to a fatigue fracture.

In this paper, dissimilar aluminum (Al) and copper (Cu) metals were joined together using ultrasonic metal welding (USMW), a solid-state welding technology. From the perspective of increasing the base metal welding contact area, the Cu/Al mating surface was innovatively prepared and ultrasonically welded. A comprehensive analysis was carried out on the forming quality, welding process temperature, interface structure, and mechanical properties of the welded joint. Defect-free and squeezed welds were successfully achieved by machining novel patterns especially C4-2. The results indicated that the reference joint can withstand higher loads, but its failure mode is very unstable. Failure may occur at welded interface and on the aluminum plate which is not good for actual production applications. Welded strength of reference joint was 4493 N, and the welded strength of C4-2 joint was 3691 N. However, microscopic analysis discovered that the welded joint internal morphology in C4-2 was more stable and hardest. C4-2 joint has successfully achieved higher tensile strength and stability under failure displacement of 38% which is higher than C4-1 joint. All welded joint failures occurred on aluminum plate, indicating that the joint strength is higher than that of bottom plate. This is attributed to unique structural design of chiseled joint and lesser thickness. SEM–EDS results investigated that the C4-2 joint can transfer more energy to area under welding head which provides welded joint with robust diffusion capacity. The transition layer has a higher thickness while the energy transferred to area away from welding head was smaller. Thickness of transition layer is significantly reduced and reference joint has similar diffusion characteristics. Conversely, the thickness of the transition layer at the corresponding position is smaller than that of pattern morphology. This is due to overall smaller thickness of the pattern joint which is more conducive to the transfer of welding energy. The surface-conformed approach and comprehensive temperature analysis provide a new understanding of USMW in dissimilar welded metals.

Dye Sensitized solar cells (DSSC) are also referred to as dye sensitised cells (DSC) or Graetzel cell are the device that converts solar energy in to electricity by the photovoltaic effect. This is the class of advanced cell that mimics the artificial photosynthesis. DSSC fabrication is simple and can be done using readily available low cost materials that are nontoxic, environment friendly and works even under low flux of sunlight. DSSC exhibits good efficiency of ~ 10-14 %. This paper emphasis on the study of enhancing the efficiency of DSSC by exposing the photo anode to microwave frequency. Effect of duration of microwave exposure at 2.6 GHz on energy efficiency of solar cell is studied in detail. The SEM analysis and dye desorption studies of the photo anode confirms an increased solar energy conversion efficiency of the DSSC.

This study examines the strength characteristics and microstructural evolution of welded joints in X10CrWMoVNb9-2 (P92) steel piping used for pressure-critical components in power generation systems. The research evaluates the effects of prolonged thermal exposure through 3,000 and 10,000 h annealing cycles at 650°C. Microstructural analyses were conducted using scanning electron microscopy (SEM), while mechanical performance was assessed via tensile testing. The investigation identified a direct correlation between microstructural degradation and diminished mechanical performance, a critical factor for high-temperature applications. Strength reductions were attributed to progressive coagulation of M23C6 carbides and Laves phase precipitation. The comparative analysis quantified property changes between the as-received parent material and weld metal, establishing baseline-to-aged condition performance metrics. These findings underscore the importance of microstructural stability in maintaining the operational integrity of P92 steel components under prolonged thermal stress, particularly in ultra-supercritical power plant environments.

In this paper, studies concerning the changes brought by gamma radiation on some PVC plates were made. The respective samples were exposed to gamma irradiation, at room temperature and different doses, such as (10, 20, 40, 80) kGy. The changes in the irradiated PVC plates’ properties were studied by UV-Vis, electrical measurements, and SEM analysis on non-irradiated and irradiated samples. The results show that gamma irradiation affects the properties of PVC plates. This degradation leads to the appearance of free radicals, the interruption of polymer chains, reticulation, and the decrease of molecular weight.

Background Teacher-student interactions and proximity have been shown influential in second/foreign (L2) education. However, the role of L2 teachers’ immediacy behaviors on students’ willingness to communicate (WTC) and academic engagement remains relatively unexamined in the context of English as a foreign language (EFL). Purpose This study intended to examine the association among EFL teachers’ immediacy behaviors and students’ WTC and engagement. Methods In this quantitative study, three online questionnaires were completed by 400 Chinese EFL students in different universities out of which 364 were valid. Results The results of statistical analysis and structural equation modeling (SEM) indicated that teachers’ immediacy behaviors (verbal, nonverbal) had a highly significant influence on EFL students’ WTC (ß=0.89, p = .000) and academic engagement (ß=0.71, p = .000). It was also revealed that teachers’ immediacy could predict 89% and 71% of variances in students’ WTC academic engagement, respectively. Conclusions Based on the results, I could be concluded that EFL teachers’ interpersonal communication abilities (e.g., immediacy) foster the establishment and growth of other positive outcomes among learners. Implications The study presents some conclusions and practical implications for EFL teachers, materials developers, and trainers to integrate the nonverbal cues of L2 communication into their practices. Such practices have the potential to enhance students’ willingness to communicate (WTC) and improve academic engagement.

The reinforcement of natural fibre and fillers in polymer resin is the latest trend followed by research groups and industries for the development of sustainable composites. Basalt fibre and waste marble powder are naturally occurring substances used to enhanced polymer properties. The present research examined the effect of both basalt fibre and waste marble powder in epoxy resin. The hand lay-up method was employed to fabricate the composite and test for mechanical and wear behaviour. The tensile, flexural, and impact energy were enhanced up to 7.5 wt. % of WMP, and the Vickers hardness of epoxy enhanced every state of reinforcement of WMP. The specific wear rate was observed to be increased with the addition of WMP until 7.5 wt. %. Scanning electron microscopy was performed to examine the nature of fractured surface wear phenomena.

In this work, the modification process of poly(lactic acid) (PLA) with metal-based nanoparticle (NPs) additives (Ag, ZnO, TiO2) at different loading (0.5, 1.0, and 2.5 wt%) and by melt-mix extrusion method followed by film formation as one of the advantageous techniques for industrial application have been investigated. PLA nanoparticle composite films (PLA-NPs) of PLA-Ag, PLA-ZnO, PLA-TiO2 were fabricated, allowing convenient dispersion of NPs within the PLA matrix to further pursue the challenge of investigating the surface properties of PLA-NPs reinforced plastics (as films) for the final functional properties, such as antimicrobial activity and surface mechanical properties. The main objective was to clarify how the addition of NPs to the PLA during the melt extrusion process affects the chemistry, morphology, and wettability of the surface and its further influence on the antibacterial efficiency and mechanical properties of the PLA-NPs. Therefore, the effect of Ag, ZnO, and TiO2 NPs incorporation on the morphology (SEM), elemental mapping analysis (SEM-EDX), roughness, surface free energy (SFE) of PLA-NPs measured by goniometry and calculated by OWRK (Owens, Wendt, Rabel, and Kaelble) model was evaluated and correlated with the final functional properties such as antimicrobial activity and surface mechanical properties. The developed PLA-metal-based nanocomposites, with improved mechanical and antimicrobial surface properties, could be used as sustainable and biodegradable materials, offering desirable multifunctionalities not only for food packaging but also for cosmetics and hygiene products, as well as for broader plastic products where antimicrobial activity is desirable.