Flexible and multifunctional ultraviolet–visible (UV–Vis) photodetectors are highly desirable for next-generation wearable healthcare devices. In this work, we report novel PVC/n-ZnO/p-MxOy (M = Ni, Cu, Ag) heterojunction composite films designed as broadband photodetectors with additional antibacterial functionality. The ZnO/MxOy composites were synthesized via a hydrothermal method and embedded within a polyvinyl chloride (PVC) matrix to yield flexible films. Structural, morphological, and optical characterizations (XRD, FTIR, SEM, EDX, UV–Vis) confirmed high-purity heterojunction formation, good crystallinity, and homogeneous morphology, with broad absorption (200–800 nm) and tunable bandgaps (1.4–3.24 eV) due to the presence of secondary metal oxides (NiO, CuO, Cu2O and Ag2O) alongside ZnO. Antibacterial activity was evaluated using the agar diffusion method, revealing strong inhibition against Gram-positive bacteria (Bacillus and Staphylococcus aureus). Photodetection performance was studied via current–voltage (I–V) measurements under dark, UV, and visible light. All devices exhibited rectifying behavior, confirming efficient n–p heterojunction formation. Among the tested devices, the PVC/ZnO/Ag2O heterojunction exhibited superior performance, achieving a responsivity of 12.7 µA/W and a detectivity of 3.08 × 10⁸ Jones under UV illumination at 5 V bias. I–t measurement revealed stable and repeatable switching, with rise and decay times of 85 s and 130 s, respectively. The device also demonstrated outstanding long-term reliability, maintaining 97
Because water is needed more around the world, new ways of using solar stills, a type of sustainable desalination, should be created to improve their performance. This review looks at how reflectors work in several types of solar stills to improve the overall performance. Inclined solar stills that have top and bottom reflectors had the highest water productivity of 4.2 kg m−2, and water generated from PV-solar stills with reflectors and cooling was much higher than before, showing a 40.98
This study investigates the influence of rotational speed (1000–2000 rpm) on the microstructural evolution, crystallographic texture, recrystallization mechanisms, and microhardnessof dissimilar C45/E335 steel joints produced by rotary friction welding. Optical microscopy, energy-dispersive X-ray spectroscopy (EDS), electron backscatter diffraction (EBSD), and Vickers microhardness mapping were employed to establish quantitative process–structure–property relationships.Optical microscopy revealed that increasing rotational speed enhances interfacial mixing and promotes greater plastic deformation within the central weld zone. As rotational speed increases, the microstructure in this region becomes progressively refined and strain-affected.Hardness mapping demonstrated that the maximum hardness was consistently located in the thermo-mechanically affected zone (TMAZ), reaching 310 HV at 2000 rpm. In contrast, lower hardness values were measured in theheat-affected zones(HAZ), reflecting thermally induced recovery and grain coarsening. Notably, the region of maximum hardness shifts toward the C45 steel side, whereas the E335 steel exhibits a wider HAZ and lower local hardness. Furthermore, hardness increases with increasing rotational speed, indicating stronger deformation-induced strengthening at higher thermomechanical inputs.EBSD-based analyses of grain orientation spread (GOS), low-angle grain boundary fraction, and geometrically necessary dislocation density revealed microstructural and crystallographic gradients across the weld seam, including variations in grain size, low-angle grain boundary fraction, geometrically necessary dislocation density, and texture intensity. Therefore, microstructural evolution in the TMAZ is dominated by continuous dynamic recrystallization (CDRX), characterized by subgrain rotation, progressive LAGB formation, and relatively diffuse texture components. With increasing rotational speed, enhanced thermal input promotes grain boundary mobility and selective growth of strain-free grains, indicating a transition toward discontinuous dynamic recrystallization (DDRX), particularly in regions experiencing elevated temperatures and lower deformation such as the HAZ. This CDRX-to-DDRX shift is reflected by changes in GOS distributions, texture sharpening along the γ-fiber, and local variations in hardness.Overall, the results demonstrate that rotational speed governs the development of asymmetric thermomechanical gradients, which in turn control recrystallization behavior, texture evolution, and local microhardnesswithin the welded joint.
This review provides a concise evaluation of advancements in micro- and nano-encapsulated phase change materials (M/N-ePCMs) for improving the thermal efficiency and stability of solar water systems. It examines encapsulation techniques—physical, chemical, hybrid, and industrially scalable—that enhance thermal conductivity, latent heat storage, and environmental durability, addressing challenges like PCM leakage and poor heat transfer. The application of ePCMs in solar water heaters, stills, ponds, and tanks is explored, emphasizing their role in stabilizing temperatures, extending operational periods, and boosting energy efficiency. Insights from experimental and numerical studies highlight performance improvements across various system designs and encapsulation methods. The review also covers relevant modeling frameworks, including solar thermal efficiency, exergy analysis, and storage metrics, summarizing key experimental data to inform future optimizations. Challenges such as cyclic stability, material compatibility in aqueous settings, and cost-effective scalability are discussed, with recommendations for advanced material selection, scalable encapsulation, and hybrid system integration. This work serves as a key resource for developing sustainable, high-performance solar thermal systems in water-scarce and off-grid regions.
The urgent need to find efficient and sustainable technological means of drying products is explained by the high post-harvest losses, unstable energy availability, and the harmful environmental effects caused by conventional ways of drying the products. This is a comprehensive review of the latest developments in HSDs that combine solar power with ancillary power sources, including heat pumps, biomass, geothermal, Liquefied Petroleum Gas (LPG), electricity, and wind power to maintain constant and regulated operation. This analysis, which extends to food and agricultural (e.g., fruits, vegetables, grains, spices), wood, medicinal plants, and new industrial applications (coffee and bricks), shows that hybrid designs are far more effective than the time-tested solar and open-sun drying systems. Hybrid types are much more efficient, exergy efficiencies are generally above 80 %, and Specific Moisture Extraction Rates (SMER) may go well above 0.87 kg/kWh, far out of the game compared with standalone systems. The most notable are significant reductions in drying time (as much as 70 %), the quality of the end product, and energy consumption. Moreover, the analysis of economic and environmental performance shows that payback time can be shortened (down to 0.08 years corresponds to approximately 29 days), a considerable amount of CO2 can be saved (up to 3074 kg/year per system), and operational costs can be saved on a significant scale. It ends by confirming that Hybrid Solar Dryers (HSDs) are a technologically viable and cost-effective solution to sustainable food preservation and biomass processing to bring predictability to situations when solar is unavailable and to improve energy security and environmental sustainability. The way forward should be to standardize performance measures, streamline control systems, and minimize initial capital costs to facilitate wider adoption.
