Abstract In this paper, we discuss the effects of sintering temperature on the properties of diatomite ceramic biomaterials. Diatomite from Cyclostephanos sp. was sintered at 950 °C, 1100 °C, and 1250 °C to evaluate how thermally driven phase transitions, pore architectures, and wetting behaviour govern its application for cell culturing and tissue scaffolding. X-ray diffraction revealed that sintering at 1100 °C and 1250 °C produced predominantly β−cristobalite ceramics, whereas 950 °C samples retained substantial amorphous silica, leading to rapid disintegration in aqueous media and exclusion from biological testing. Model endothelial cells (MDCK-2) exhibited good adhesion and proliferation on both 1100 °C and 1250 °C ceramics, with significantly higher cell densities observed on 1250 °C samples from days 6-8. Image-based pore analyses revealed that 1250 °C sintering generated larger and more numerous micron-scale pores, as well as a 1.18-fold increase in water imbibition velocity, suggesting enhanced early-stage cell attachment via improved capillarity and surface accessibility. Both materials have shown similar efficacy as bioplatforms for pre-osteoblasts (MC3T3-E1) differentiation and mineral deposits formation. Collectively, the results show that sintering temperature critically determines crystalline phase, mechanical stability, and pore morphology, which in turn affects cell proliferation rate.
Abstract Environmentally friendly materials made from renewable resources, have received much attention lately in green chemistry. In this study the structural and optical characteristics of polyvinyl alcohol (PVA) thin films containing natural dye derived from Solanum lycopersicum (tomato) peel were examined. The results of XRD analysis shows that the intensity of the characteristic diffraction peaks reduces, indicating an increase in the amorphous fraction in the polymer composite films. The FTIR spectra show a strong interaction between the functional groups of the tomato peel dye (TPD) and the PVA matrix. Data from UV-Vis-NIR tests show that doping causes enhanced light absorption and redshift in the absorption edge. Using Tauc and dielectric loss techniques, the energy band gap drops from 5.15 eV for pure PVA to 4.78 eV for the dye-doped film. Additionally, a refractive index increase to the value of 2.65 for the doped compound. All samples exhibit direct forbidden electronic transitions. These findings demonstrate that tomato peel-derived dye is an effective, sustainable modifier for tailoring the optical properties of PVA for potential optoelectronic applications.
Silk cocoons of the domesticated silkworm Bombyx mori exhibit exceptional mechanical performance, serving as natural protective casings evolved over millennia to resist environmental threats and predation. This review critically examines the relationship between the cocoon’s molecular composition, hierarchical architecture, and its multifunctional mechanical behaviour. We begin by reviewing the primary and secondary structures of silk proteins, particularly fibroin and sericin, and their contribution to β-sheet crystallinity and tensile strength. At larger length scales, the anisotropic, multilayered structure of the cocoon wall demonstrates a strategic gradation in porosity, fibre density, and mechanical stiffness from outer to inner layers, supporting a synergistic defence strategy. Mechanical tests reveal notable resistance to tensile, tearing, stabbing, and puncture loads, with measured values that at times, outperform synthetic polymers, foams, and textiles. Finite element simulations further elucidate the cocoon’s stress redistribution mechanisms under a range of loading scenarios. Drawing from these insights, this review identifies critical knowledge gaps, particularly in interfacial mechanics, environmental effects, and hierarchical modelling, and outlines promising directions for bioinspired material design. We find that the B. mori cocoon is a model of evolutionary optimization, and a blueprint for next-generation damage-tolerant structures.
Efficient thermal management is crucial in microfluidic heat exchangers operating under high heat flux conditions. This study evaluates a copper microfluidic heat exchanger enhanced with nano-encapsulated phase change materials (NEPCMs), comprising a paraffin core enclosed in silica shells. The NEPCM exhibited a particle size of 78 +/- 2 nm, a thermal conductivity of 0.55 W/m & centerdot;K, and a latent heat capacity of 199.3 J/g, confirmed through DSC and thermal conductivity measurements. Experiments were performed using deionized water at flow rates ranging from 10 to 50 ml/min with an inlet temperature of 298 K. The incorporation of NEPCM significantly strengthened the system's thermal management capability, reducing thermal resistance from 0.83 K/W to 0.57 K/W (31.3% improvement) and increasing the heat transfer coefficient from 1360 W/m2 & centerdot;K to 1845 W/m2 & centerdot;K (35.7% enhancement) at 30 ml/min. Importantly, the outlet temperature decreased from 308.7 K to 302.0 K-a 6.7 K drop-while temperature fluctuations during transient loading were reduced by 13.2%, demonstrating improved cooling effectiveness and thermal stability. A CFD model was subsequently developed in ANSYS Fluent and validated using the experimental measurements, with deviations within 4%, confirming the reliability of the numerical framework. Overall, the results highlight the strong potential of NEPCMs to enhance heat dissipation, stabilize operating temperatures, and improve the thermal management performance of compact microfluidic systems used in electronics cooling and lab-on-chip applications.
This work presents the development and experimental characterization of semiconductor ionizing-radiation detectors based on p-Si/n-InP heterostructures. The devices were fabricated using a surface-barrier technology employing high-resistivity p-type silicon substrates and thin n-InP layers deposited by vacuum evaporation. Key electrical and radiometric parameters were measured at room temperature, including a dark current of 0.5-1 mu A, capacitance in the range of 700-1800 pF, and an energy resolution of 60-65 keV for 7.68 MeV alpha-particles. The heterojunction demonstrated high sensitivity to low-intensity alpha-radiation (2 & sup3;8Pu, 2 & sup3;9Pu, 2 & sup3;& sup3;U, 226Rn), which is attributed to the wide bandgap of InP (1.34 eV) and its compatibility with silicon-based fabrication processes. The obtained results highlight the potential of p-Si/n-InP structures for advanced applications in nuclear physics, environmental radiation monitoring, and space instrumentation.
