بحث تخرج متكامل في تخصص إدارة الأعمال مع تنسيق أكاديمي كامل ونسبة استلال 5%

رسالة ماجستير شاملة تتضمن بناء نظام برمجي وتحليل إحصائي SPSS

نظام متكامل لإدارة المكتبات باستخدام C# .NET وقاعدة بيانات SQL Server

منصة تجارة إلكترونية متكاملة بتصميم عصري ولوحة تحكم إدارية

This study investigates the electro-optical enhancements induced by the dispersion of ferroelectric barium titanate (BaTiO3) nanoparticles within a side-chain liquid crystalline polyacrylate matrix maintained at a constant molecular weight of . To establish definitive structure-property correlations, the nanocomposites were formulated across five distinct BaTiO3 additive ratios and rigorously characterized utilizing X-ray scattering and infrared dichroism to determine the orientational order parameters. Thermal and microstructural analyses confirmed that all synthesized polymeric formulations successfully exhibited a stable nematic mesophase. Empirical evaluations revealed that escalating the ferroelectric nanoparticle concentration actively increased the packing density of the mesogenic pendant groups associated with the primary polymer chain. This structural densification substantially magnified the localized dipole torque contribution acting strictly parallel to the longitudinal axis of the mesogenous units. Consequently, this microscale dipole amplification generated a profound improvement in the macroscopic dielectric anisotropy of the composite network. Electro-optical measurements demonstrated that this engineered anisotropy directly translated into a significant decrease in the required operation voltage and remarkably accelerated optical response dynamics, minimizing both the activation () and relaxation () switching times. Furthermore, spectroscopic tracking of the highly polar cyano (CNN) absorption band established that the coefficient of the directional arrangement remains fundamentally temperature-dependent. The convergence of lowered energetic thresholds, rapid field-induced reorientation, and robust thermodynamic stability definitively proves the exceptional viability and efficiency of these novel BaTiO3-doped polyacrylate nanocomposites for integration into advanced optoelectronic applications

The proliferation of autonomous wireless sensor networks and the Internet of Things (IoT) requires sustainable alternatives to finite and environmentally hazardous electrochemical batteries. Piezoelectric energy harvesting (PEH) offers a promising solution by scavenging ambient kinetic energy; however, practical deployment is often hindered by frequency mismatches and electrical conversion inefficiencies. This study conceptualizes, fabricates, and empirically evaluates a physical PEH prototype integrated into a scaled two-lane smart roadway model. Piezoelectric sensors were embedded beneath designated pressure pads to capture mechanical stress from simulated vehicular traffic. The generated alternating current (AC) was rectified and conditioned via a power management module (TP4056) to safely charge a 3.7V, 1200mAh 18650 lithium-ion battery, while real-time voltage metrics were continuously acquired using an Arduino Uno microcontroller. Experimental testing under incremental mechanical loads of 500N, 700N, 900N, 1000N, and 1200N demonstrated a direct correlation with the electrical output, yielding transient potentials of 1V, 2V, 3V, 4V, and a peak of 5V, respectively . The conditioned energy successfully charged the battery reservoir and was systematically discharged to illuminate an array of miniature LED streetlights. These empirical results definitively validate the electromechanical viability of scavenging erratic, low-grade mechanical oscillations from transit environments to autonomously power decentralized municipal infrastructure.