http://103.99.128.19:8080/xmlui/handle/123456789/43 All Digital Collections of ME 2026-11-14T12:14:19Z http://103.99.128.19:8080/xmlui/handle/123456789/615 Study of Mechanical and Hydrophilic Characteristics of Hybrid Composites Manufactured by Vacuum Infusion Process Chowdhury, Al Amin; ID:, 18MME030P The increasing demand for lightweight, durable, and multifunctional materials in various engineering sectors have encouraged extensive research into hybrid composite materials. Hybrid composites, which combine different fiber and matrix constituents, offer enhanced mechanical properties and tailored functionalities, making them a promising alternative to traditional composites. This study involves fabricating hybrid composites comprising synthetic glass fibers and natural jute fibers in a polymeric matrix. The vacuum infusion process setup was developed to optimize resin distribution and minimized void content, crucial for achieving consistent mechanical performance. Comprehensive mechanical testing like tensile, flexural, hardness and impact tests were conducted to evaluate the mechanical behavior of the fabricated hybrid composites. In the study, only jute fiber composite has shown lower tensile stress, flexural stress, Impact strength and hardness. On the other hand, blending of jute with glass fiber hybrid composites have shown higher Tensile Stress(237%), Flexural Stress (800%), Impact Strength (1800%) and Hardness (22%). The stacking sequence of jute and glass fiber in the composite lamina has significant influence on the mechanical properties of the hybrid composite. The mechanical properties like tensile stress increases 11.62%, flexural modulus increases 61%, impact strength increases 60% and hardness value remained unchanged while changing the stacking sequence of jute and glass fiber in the composite laminate. The water absorption behavior of the hybrid composites were also analyzed both in fresh and salt water. The glass fibers at the outer layers of the hybrid composite lamina reduces water absorption. The jute fibers at the outer layers of the composite lamina increases fresh water absorption (1.35%, 0.86%, 3.72% and 1.26%) and comparatively reduced salt water absorption (0.47%, 0.46%. 1.60% and 0.80%). The experimental result indicates that the jute glass fibers hybrid composite has exhibited a synergistic improvement in the mechanical performances by leveraging the high strength of synthetic fibers and the eco-friendliness of the natural fibers. However, surface treatments of fibers were found to significantly improves mechanical properties by enhancing fiber-matrix adhesion and reducing moisture ingress. The findings contribute to the development of next-generation composite materials for applications in automotive, aerospace, and marine industries, where mechanical robustness and environmental sustainability are paramount. A Master of Science (M.Sc) Thesis in Mechanical Engineering (ME) Department at Chittagong University of Engineering and Technology (CUET). 2025-08-26T00:00:00Z http://103.99.128.19:8080/xmlui/handle/123456789/614 Experimental Analyses and Characterization of Natural Fiber Reinforced Polymer Composites Produced by Injection Molding Method HASAN, MURTAJA; ID:, 16MME025P Natural fibers have been used as reinforcement in composite development over synthetic fiber in the recent years due to the biodegradability, sustainability, availability, recyclability and clean environment. This study examines the prospect of jute fiber using as reinforcement in High-Density Polyethylene (HDPE) composites. Three different fiber weight fractions of 5%, 10% and 20% have been considered and termed as HDPEDJ-5, HDPEDJ-10, and HDPEDJ-20, correspondingly. Jute fiber was chemically treated as a part of the surface modification using 5% NaOH to adhere the bonding between reinforcement and matrix. Injection molding technique has been employed to prepare the samples as per the ASTM standards. The effect of the amount of fiber on composite performance was investigated through tensile strength, impact strength and hardness. In mechanical characterization, the HDPEDJ-10 sample provided better results by showing 25.5 MPa of tensile strength and 3.15 kJ/m2 of impact strength, whereas HDPEDJ-5 sample exhibited maximum Rockwell hardness of 90.9 RHB. It was observed from the data that the mechanical properties of the material improved as the content of jute fiber increased, which posits this eco-friendly composite as a potential candidate for industrial usage. A Master of Science (M.Sc) Thesis in Mechanical Engineering (ME) Department at Chittagong University of Engineering and Technology (CUET). 2025-08-26T00:00:00Z http://103.99.128.19:8080/xmlui/handle/123456789/611 Numerical Study of Aerosol Deposition in a Realistic Human Lung in Different Body Orientations Dev, Turag; ID:, 22MME026F The success of targeted drug delivery through inhalation largely depends on the efficient deposition of aerosols across different regions of the human lung. Factors such as particle size, airflow dynamics, lung geometry, and body posture have a significant influence on aerosol transport and deposition. This computational fluid dynamics (CFD)-based study investigates the combined effects of body orientation and particle size on aerosol deposition using a realistic lung geometry reconstructed from computed tomography (CT) images and a realistic aerosol breathing profile derived from patient data. Simulations were conducted in ANSYS Fluent using the Discrete Phase Model (DPM) for five particle sizes (3, 5, 7, 9, and 10 µm) across three body orientations: upright, dorsal, and lateral. Results showed that total deposition efficiency increased with particle size, while regional deposition varied noticeably with posture. The right lung consistently exhibited higher deposition than the left, and the upper lobes of both lungs received the majority of particles, particularly for larger aerosols. Although overall deposition efficiency remained similar across orientations, regional redistribution was evident. These findings highlight how body posture influences aerosol transport within the lungs and offer valuable insights for optimizing posture based inhalation strategies and improving targeted drug delivery. A Master of Science (M.Sc) Thesis in Mechanical Engineering (ME) Department at Chittagong University of Engineering and Technology (CUET). 2025-07-31T00:00:00Z http://103.99.128.19:8080/xmlui/handle/123456789/598 Experimental Study on The Effect of Skin Friction Drag and Convective Heat Transfer for Pseudoplastic & Viscoelastic Fluid Flow. Ahammed, Meraz; ID:, 21MME007P Drag reducing agents (DRAs) has a huge impact and a major concern in the engineering field and industrial applications. It makes the fluid flow turbulent to laminar, dampens eddy and reduces head loss by up to a certain limit and saves pumping energy costs. Viscosity is the property which dampens eddy due to viscous effect increases the fluidity up to a certain limit. Pseudoplasticity is the shear thinning effect that decreases viscosity when flowrate increases. So for viscoelastic effect we can increase the concentration up to a certain limit to reduce head loss but during flow due to pseudoplastic effect the viscosity will start decreasing which is negative effect. So these combined effect is studied to reduce skin friction drag in pipline and save energy cost which will be convenient for food industry, chemical and medicine industry. In this investigation, investigation is carried out for 0.3 g/L, 0.2 g/L and 0.15 g/L of xanthan gum in turbulent flow to observe the pressure drop and heat transfer rate. The study reveals that after increasing viscosity the pressure drop reduced significantly. Conversely the heat transfer rate also reduced due to poor mixing effect. A higher performance and less vibration of pump was also observed. It was concluded that frictional pressure drop was reduced up to 85% and heat transfer rate reduced up to 90% by increasing the concentration of the DRA(drag reducing agent) up to 0.3 g/L at 10 LPM than the pure water or base fluid as working substance on double pipe heat exchanger. As the heat transfer rate reduced up to 90% with reducing pressure drop so another aim of the study was to establish a concentration and flowrate for which heat transfer rate is maximum and it was found at concentration of 0.15 g/L of DRAs(drag reducing agents) at 22 LPM(maximum flowrate at this setup). A Master of Science (M.Sc) Thesis in Mechanical Engineering (ME) Department at Chittagong University of Engineering and Technology (CUET) 2024-12-15T00:00:00Z