Preparation and Characterization of Composites Based on Natural Fibers

, M.Sc. Thesis Sharif University of Technology Bapiri, Pardis (Author) ; Shojaei, Akbar (Supervisor) ; Esfandeh, Masoud (Supervisor) ; Rezadoust, Amir Masoud (Co-Supervisor)

Abstract

In this research, coating with polymer solution was considered for improve the surface adhesion of natural jute fibers with polymer matrix. This coating was performed by two polymers, polyurethane and polystyrene, in order to create compatibility between natural fibers and unsaturated polyester resin. Impregnation and coating of fibers were done by dissolving these polymers in a suitable solvent and creating a thin coating on the fibers. 2%, 5% and 10% solutions of each polymer were prepared for impregnating fibers and the pultrusion process of the resulting fibers was performed using unsaturated polyester resin. The polyurethane were not compatible with jute fibers and caused a loss of...

Scattering Correction in PET Device using Deep Learning

, M.Sc. Thesis Sharif University of Technology Kamalizadeh, Zeynab (Author) ; Vosoghi, Naser (Supervisor) ; Ghaffarian, Pardis (Co-Supervisor) ; Sheikhzadeh, Peyman (Co-Supervisor)

Abstract

Positron Emission Tomography (PET) imaging is a modern sectional imaging technique widely used due to its advantages in visualizing the physiological functions of body tissues. In this method, a radiotracer is injected into the body, concentrating in the area of interest. As the positron-emitting radionuclide decays, positron annihilation occurs, resulting in the emission of two gamma rays in opposite directions. The PET scanner detects these gamma rays; however, scattering may occur during their journey from the patient’s body to the detector, which can introduce errors in tumor localization. To reconstruct images and correct for these scatter effects, various techniques such as iterative...

Enhancement Of the Quality In PET Brain Images Using AutoGANcoder Algorithms

, M.Sc. Thesis Sharif University of Technology Razavi Satvati, Reyhaneh Sadat (Author) ; vosoughi, Naser (Supervisor) ; Ghafarian, Pardis (Co-Supervisor) ; Attari, Ali Akbar (Co-Supervisor)

Abstract

Positron Emission Tomography (PET) is a cutting-edge medical imaging technique that enables the examination of functional activities in different regions of the body, particularly the brain. This technique involves injecting a radiopharmaceutical into the body, which emits gamma rays that are subsequently detected by the PET scanner to generate images. However, a significant challenge in PET imaging is the degradation of image quality due to noise and photon scattering, which can lead to diagnostic errors, especially in sensitive applications such as detecting brain diseases. Various image reconstruction techniques have been developed in the past to mitigate attenuation and scattering...