Effects of isotropic stress on the band structure elastic, optical, thermal, and x-ray diffraction properties of TiSnO3.

BACKGROUND: Cubic perovskite titanium stannous oxide (TiSnO3) is a promising material for various applications due to its functional properties. However, understanding how these properties change under external stress is crucial for its development and optimization. METHOD: This study employed density functional theory calculations to investigate the structural, electronic, optical, thermal, and mechanical properties of TiSnO3 under varying degrees of external static isotropic stress (0-120 GPa). RESULTS: The study reveals a significant decrease in the bandgap of TiSnO3 with increasing stress due to lattice modifications and the formation of delocalized electrons. Partial density of states analysis indicates that Sn and O states play a key role in shaping the electronic band structure. TiSnO3 exhibits increased light absorption with stress, accompanied by a blue shift in absorption peaks, whereas, both polarizability and refractive index decrease with increasing stress. Mechanically, all elastic moduli (bulk, shear, and Young's) show an increase under stress, signifying a stiffening response of the material under stress. Similarly, the Pugh ratio suggests a transition from ductile to brittle behaviour at elevated stress levels. Phonon dispersion calculations indicate the instability of the cubic phase at 0 K. However, a phonon gap emerges at 30 GPa and widens with increasing stress. X-ray diffraction further supports these findings by demonstrating a shift in diffraction peaks towards higher angles with increasing stress, consistent with the applied stress. CONCLUSION: In conclusion, this computational study offers a thorough understanding of how external stress influences the properties of TiSnO3, providing valuable insights for potential applications in various fields.

Development of a dual point humidity sensor using POF based on twisted fiber structure.

The humidity has often been measured through a single point sensor. Where, the humidity could be varied at different locations as well as depending on environmental conditions. The present paper developed the dual point humidity measuring sensor by using a polymer optical fiber (POF) based on a single illuminating fiber. The sensor's basic structure is to twist two fibers and bend them at a certain radius. However, the dual point sensor is developed through the cascading of twisted micro bend (TMB-1 and TMB-2). The twisting of fibers couples the light from one fiber to another fiber through the side coupling method. An increase in the humidity level leads to a change in the reflective index, which helps to get variation in coupled light intensity. To measure the humidity, the dual point sensors are placed into the control humidity chamber at two random positions. The power reading variation is significantly linear when the humidity level increases from 30 to 80%. The sensor has a fast response of about 1 s and a recovery time of about 4 s. Furthermore, the chemical coating is applied to improve the sensor's sensitivity. Between 30 and 80% range of humidity, the both sensors of dual point TMB-1 and TMB-2 have appropriate sensitivity and detection limits, which is about 680.8 nW/% and 763.9 nW/% and 1.37% and 1.98%, respectively. To measure the humidity at variable positions, the present dual points humidity sensor is well-stable, easy, and straightforward, which uses a less expensive method.

Preparation and Characterisation of Sustainable Wood Plastic Composites Extracted from Municipal Solid Waste.

Municipal solid waste (MSW) contains plastic waste that can be used as a sustainable green substitute to reduce oil footprints, CO2 emissions, and environmental pollution. This study aims to recycle plastic waste by manufacturing wood-plastic composites and to improve its mechanical properties by using additives, coupling agents, and lubricants. These composites are prepared by mixing 40-70% of wood flour with 20-25% of a polymer matrix. Wood was degraded at 220 °C, and then the composites were processed at 50 °C. The manufacturing process carried out in the study involved wood waste meshing, drying, shredding, drying, trimming, filling, blending, compounding, and extrusion moulding. The compounding of composites was accomplished in twin-screw extruders. Once the mixture was uniformly mixed, its final shape was given by a two-step extrusion moulding. Previously, researchers aimed at enhancing the mechanical properties of the composites, but our research focus was to improve their durability for different industrial applications. The results suggest that the impact strength is 17 MPa with 50% of wood powder ratio while the maximum value for the tensile strength is 32.5 MPa. About 50% of an increase in wood powder resulted in 8.1% bending strength increase from 26.1 to 32.8 MPa. Reducing the plastic matrix and the wood-particles water swelling ratio resulted in better mechanical properties. The wood species also affected the mechanical properties with their excellent dimensional stability and less variability. A high proportion of wood fibre tends to increase its steady-state torque and viscosity. The mechanical properties against different wood-flour proportions indicate that composite materials exhibit superior water swelling behaviour and extrusion quality.