The dielectric properties of Au/PPy/n-Si metal-polymer-semiconductor (MPS)-type Schottky barrier diodes (SBDs) were investigated by using capacitance-voltage (C-V) and conductancevoltage (G/ω-V) measurements at various temperatures and voltages at frequencies of 100 kHz and 500 kHz. Both the real and the imaginary parts of the complex dielectric constant and dielectric loss (ε′, ε″) and of the electric modulus (M′, M″), as well as the conductivity (σ_ac), were found to depend strongly on the temperature and the voltage. Both the C and G/ω values increased with increasing applied voltage and had inversion, depletion, and accumulation regions as with a metal-insulator-semiconductor (MIS) type behavior. Both the dielectric constant (ε′) and the dielectric loss (ε″) increased with increasing temperature and decreased with increasing frequency. The loss tangent (tan δ) vs. temperature curve had a peak at about 200 K for both frequencies. The M′ and the M″ values decreased with increasing temperature and became independent of the frequency at high temperatures. The series resistance (R_s) of the diode decreased with increasing temperature for the two frequencies while the σ_ac increased. Such behaviors of the dielectric properties with temperature were attributed to the restructuring and reordering of charges at interface states/traps due to the varying temperature, the interfacial polarization, and the interfacial polymer layer. ln(σ_ac) vs. q/kT plots had two distinct linear regions with different slopes for the two frequencies. Such behaviors of these plots confirmed the existence of two different conduction mechanisms corresponding to low and high temperatures. The values of the activation energy (E_a) were obtained from the slopes of these plots, and its value at low temperatures was considerably lower than that at high temperatures.

In this study, a comprehensive machine learning (ML) model was developed to predict and optimize boride coating thickness on steel surfaces based on boriding parameters such as temperature, time, boriding media, method, and alloy composition. In a dataset of 375 published experimental results, 19 features were applied as inputs to predict the boride layer thickness in various steel alloys. ML algorithms were evaluated using performance metrics like Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and R². Among the ML algorithms tested, XGBoost exhibited the highest accuracy. XGBoost achieved an R² of 0.9152, RMSE of 29.57, and MAE of 18.44. Incorporating feature selection and categorical variables enhanced model precision. Additionally, a deep neural network (DNN) architecture demonstrated robust predictive performance, achieving an R² of 0.93. Experimental validation was conducted using 316L stainless steel (SS), borided at 900 °C and 950 °C for 2 h and 4 h. The DNN model effectively predicted the boride thickness under these conditions, aligning closely with the observed values and confirming the models’ reliability. The findings underscore the potential of ML to optimize boriding processes, offering valuable insights into the relationships between boriding parameters and coating outcomes, thereby advancing surface modification technologies.

In this study, for the first time, a new generation hemp hurd/PP composite material coupling sleeve prototype production was performed for the water irrigation pipes. Within the scope of experiments, at first hemp hurds were prepared by using cyclic grinding machine. Later, the compounds of hemp hurds (0 wt%, 10 wt%, 20 wt% and 30 wt%) and polypropylene (PP) were prepared using double screw extruder machine at Ondokuz Mayıs University. After that, the specimens of 0 wt%, 10 wt%, 20 wt% and 30 wt% hemp hurd reinforced polypropylene (PP) composites were fabricated using injection molding machine. Three points bending tests were performed on the fabricated specimens with INSTRON 5982 100 KN universal test device at Ondokuz Mayıs University (OMU) KITAM Central laboratory. Prototyping of hemp hurd/PP composite material coupling sleeves were produced using plastic injection machines of Poelsan Plastik Sanayi ve Ticaret A.Ş. Long-term tightness test under internal pressure was conducted on the fabricated coupling sleeves in Poelsan Plastik Sanayi ve Ticaret A.Ş. According to the bending test results, the bending modulus of specimens were increased by increasing hemp hurd content. The highest bending strength was obtained by 10 wt% hemp hurd powder reinforced PP composites (46.5 MPa). The findings showed that the coupling sleeves manufactured from hemp hurd/PP composite material can be successfully used as an alternative to %100 PP material coupling sleeve under similar service conditions in water irritation systems.