In this research, polypropylene (PP)–graphite composites were prepared using the melt mixing technique in a twin-screw extruder. Graphite, multi-walled carbon nanotubes (MWCNT), carbon black (CB), and expanded graphite (EG) were added to the PP in binary, ternary, and quaternary formations. The graphite was used as a primary filler, and MWCNT, CB, and EG were added to the PP–graphite composites as secondary fillers at different compositions. The secondary filler compositions were considered the control input factors of the optimization study. A full factorial design of the L-27 Orthogonal Array (OA) was used as a Design of Experiment (DOE). The through-plane electrical conductivity and flexural strength were considered the output responses. The experimental data were interpreted via Analysis of Variance (ANOVA) to evaluate the significance of each secondary filler. Furthermore, statistical modeling was performed using response surface methodology (RSM) to predict the properties of the composites as a function of filler composition. The empirical model for the filler formulation demonstrated an average accuracy of 83.9% and 93.4% for predicting the values of electrical conductivity and flexural strength, respectively. This comprehensive experimental study offers potential guidelines for producing electrically conductive thermoplastic composites for the manufacturing of bipolar fuel cell plates.

Piezoelectric sensors convert mechanical stress into electrical charge via the piezoelectric effect, and when fabricated as fibers, they offer flexibility, lightweight properties, and adaptability to complex shapes for self-powered wearable sensors. Polyvinylidene fluoride (PVDF) nanofibers have garnered significant interest due to their potential applications in various fields, including sensors, actuators, and energy-harvesting devices. Achieving optimal piezoelectric properties in PVDF nanofibers requires the careful optimization of polarization. Applying a high electric field to PVDF chains can cause significant mechanical deformation due to electrostriction, leading to crack formation and fragmentation, particularly at the chain ends. Therefore, it is essential to explore methods for polarizing PVDF at the lowest possible voltage to prevent structural damage. In this study, a Design of Experiments (DoE) approach was employed to systematically optimize the polarization parameters using a definitive screening design. The main effects of the input parameters on piezoelectric properties were identified. Heat treatment and the electric field were significant factors affecting the sensor’s sensitivity and β-phase fraction. At the highest temperature of 120 °C and the maximum applied electric field of 3.5 kV/cm, the % β-phase (F(β)) exceeded 95%. However, when reducing the electric field to 1.5 kV/cm and 120 °C, the % F(β) ranged between 87.5% and 90%. The dielectric constant (ɛ′) of polarized PVDF was determined to be 30 at an electric field frequency of 1 Hz, compared to a value of 25 for non-polarized PVDF. The piezoelectric voltage coefficient (g₃₃) for polarized PVDF was measured at 32 mV·m/N at 1 Hz, whereas non-polarized PVDF exhibited a value of 3.4 mV·m/N. The findings indicate that, in addition to a high density of β-phase dipoles, the polarization of these dipoles significantly enhances the sensitivity of the PVDF nanofiber mat.

This research aims to investigate the effects of polymer matrices on the properties of electrically conductive thermoplastic composites for fuel cell bipolar plates. Thermoplastic resins are lightweight, recyclable, and easy to process into any shape. Carbon fillers that exhibit conductive characteristics are added to the polymer matrix to generate electrically conductive paths inside the matrix and make them prominently conductive. In this research, electrically conductive thermoplastic composites were produced by using a twin-screw extruder to study the effects of the bonding matrix on the electrical and mechanical properties of the composites. Graphite was used as a conductive filler and was incorporated into the Nylon and Polypropylene (PP) matrices at different loading ranging from 68 wt.% to 84 wt.%. The composites were tested for flexural strength and electrical conductivity. The properties of PP and nylon-based composites were compared and analyzed. The results showed that the PP composites have better electrical performance at higher filler loading, whereas the nylon composites displayed better mechanical properties.

The COVID-19 pandemic has sparked a paradigm change in pandemic preparedness measures, motivating an investigation of non-pharmaceutical therapies. This research dives into the lessons learned from COVID-19 to strengthen our strategy to prevent future pandemics. The study aimed to extract valuable insights from the COVID-19 experience, extrapolating lessons learned to develop strong strategies that include diet, lifestyle, risk factors and non-pharmaceutical treatments. Nutrition and lifestyle influences on illness susceptibility were studied using a comprehensive examination of scholarly literature, reports and epidemiological studies. Role of essential risk variables was investigated in magnifying pandemic outcomes and the efficiency of non-pharmaceutical treatments in reducing infectious agent transmission. The analysis demonstrates the long-term utility of COVID-19 findings. This review emphasizes the importance of nutrition and lifestyle variables in determining susceptibility to infectious illnesses. Furthermore, a detailed examination of risk variables shows critical predictors of pandemic severity. Most significantly, the findings highlight the effectiveness of non-pharmaceutical measures, emphasizing their vital role in pandemic containment. This study has far-reaching ramifications that advocate for a paradigm change towards comprehensive pandemic preparation using the lessons learned during COVID-19. Research findings highlight the need for a multifaceted strategy, including diet, lifestyle changes, targeted risk reduction and non-pharmaceutical therapies. This study provides a road map for improving global resilience to potential future pandemics, calling for preventative strategies beyond pharmacological remedies.