Atomic Layer Deposition Seeded ZnO Nanowires in Hybrid Carbon Fiber Composites: Synthesis, Characterization and Multifunctionality

Interfacial treatments of carbon fiber composites play a critical role in determining the overall performance as the surface of carbon fiber is smooth and inert causing low bonding to the polymer matrix. In this dissertation, atomic layer deposition (ALD) seeded ZnO nanowires were grown on carbon fiber as an enhanced interphase using two-step hydrothermal method for the first time. The effects of growth parameters of seed layers by ALD and nanowire growth in hydrothermal method were systematically investigated. Several morphologies of ZnO nanostructures were obtained and characterized using field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Single carbon fiber composites and carbon fiber composite laminates with ZnO nanowires were manufactured, then tested by single fiber fragmentation test, 3-point bending test, short beam 3-point bending test. It was found that the incorporation of ZnO nanowires significantly improved the mechanical properties of composites including interfacial shear strength, flexural strength and interlaminar shear strength by up to 286%,45.6% and 31.1%.The successful development and characterization of ZnO nanowires enhanced structural composites have great potential to lead to new generation of lightweight materials with increased mechanical properties for broad mechanical and aerospace engineering applications

Estimation And Tracking Algorithm For Autonomous Vehicles And Humans

Autonomous driving systems have experienced impressive growth in recent years. The present research community is working on several challenging aspects, such as, tracking, localization, path planning and control. In this thesis, first, we focus on tracking system and present a method to accurately track a moving vehicle. In the vehicle tracking, considering the proximity of surrounding vehicles, it is critical to detect their unusual maneuvers as quickly as possible, especially when autonomous vehicles operate among human-operated traffic. In this work, we present an approach to quickly detect lane-changing maneuvers of the nearby vehicles. The proposed algorithm is based on the optimal likelihood ratio test, known as Page test. Second, we consider another form of tracking: tracking the movements of humans in indoor settings. Indoor localization of staff and patients based on radio frequency identification (RFID) technology has promising potential application in the healthcare sector. The use of an active RFID in real-time indoor positioning system without any sacrifice of localization accuracy is intended to provide security, guidance and support service to patients. In this paper maximum likelihood estimation along with its Cramer-Rao lower bound of the locations of active RFID tags are presented by exploring the received signal strength indicator which is collected at the readers. The performance of real-time localization system is implemented by using an extended Kalman filter (EKF)

Analysis of swirling flow effects on the characteristics of unsteady hot-streak migration

AbstractThe temperature of flow at the combustor exit is inherently non-uniform and the hot fluid is called hot-streak. An in-house CFD software, NUAA-Turbo, was used to carry out 3D unsteady simulations on the PW-E3 single-stage high-pressure turbine. The hot-streak effect based on real stator and combustor counts was approximately evaluated by the contraction/dilatation method on the interface. The unsteady attenuation and migration process of hot-streaks in the turbine passage were well captured. The general performance parameters for different circumferential positions of hot-streaks were relatively consistent. Then, the influences of hot-streaks on blade surface temperature were investigated by comparing results under hot-streak and uniform inflow conditions. Unsteady simulations with combined inlet hot-streak and swirling flow show that the core of a hot-streak migrates to the tip under the influence of a positive swirl, while the phenomenon is just opposite with a negative swirl. Therefore, the heat transfer environment of rotor blades shows great differences with different directions of inlet swirl

The Metabolism of Baicalin in Rat and the Biological Activities of the Metabolites

Baicalin is one of the major bioactive constituents of Scutellariae Radix, but the biotransformation of it is poorly understood. In this paper, the metabolism of baicalin in rat was studied. Nine metabolites including one new compound were isolated and identified structurally. The plausible scheme for the biotransformation pathways of baicalin in the rats was deduced. And the main metabolites were evaluated for their antioxidation and anti-inflammation biological activities for the first time