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Full-Text Articles in Engineering
Security Enhancements In Voice Over Ip Networks, Seyed Amir Iranmanesh
Security Enhancements In Voice Over Ip Networks, Seyed Amir Iranmanesh
Dissertations, Theses, and Masters Projects
Voice delivery over IP networks including VoIP (Voice over IP) and VoLTE (Voice over LTE) are emerging as the alternatives to the conventional public telephony networks. With the growing number of subscribers and the global integration of 4/5G by operations, VoIP/VoLTE as the only option for voice delivery becomes an attractive target to be abused and exploited by malicious attackers. This dissertation aims to address some of the security challenges in VoIP/VoLTE. When we examine the past events to identify trends and changes in attacking strategies, we find that spam calls, caller-ID spoofing, and DoS attacks are the most imminent …
Surface Modification Of Synthetic And Natural Polymers Using Deep Uv (172 Nm) Irradiation, Lopamudra Das
Surface Modification Of Synthetic And Natural Polymers Using Deep Uv (172 Nm) Irradiation, Lopamudra Das
Dissertations, Theses, and Masters Projects
The ability to modify the surfaces of polymers and impart desirable functionalities without affecting the bulk-mediated physical properties is vital for advanced materials development. Photochemical approaches to surface modification are particularly attractive as they minimize the need for use of hazardous materials used in conventional wet chemical technologies, and are relatively faster, efficient and convenient to use. In this research, we undertook a combined experimental and computational approach to understand the effect of deep UV irradiation on a broad range of polymeric materials, and develop a scalable and deployable surface modification strategy that could be extended to all. Four polyesters, …
Surfactant Free Emulsion Polymerization Of Poly(Styrene-Co-Methyl Methacrylate): Correlation Of Microsphere Characteristics With Monomer Reactivity And Water Solubility, Samantha Applin
Dissertations, Theses, and Masters Projects
Polymeric microspheres have been used in a broad range of applications from chromatographic separation techniques to analysis of air flow over aerodynamic surfaces. The preparation of microspheres from many polymer families has consequently been extensively studied using a variety of synthetic approaches. Although there are a myriad of polymeric microsphere synthesis methods, free-radical initiated emulsion polymerization is one of the most common techniques. In this work, poly(styrene-co-methyl methacrylate) microspheres were synthesized via surfactant-free emulsion polymerization. The effects of the co-monomer composition and addition time on particle size distribution, particle formation, and particle morphology were investigated. Particles were characterized using dynamic …
Vertically Oriented Graphene Electric Double Layer Capacitors, Dilshan V. Premathilake
Vertically Oriented Graphene Electric Double Layer Capacitors, Dilshan V. Premathilake
Dissertations, Theses, and Masters Projects
Vertically oriented graphene nanosheets (VOGN) synthesized by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) have been fabricated as electrical double layer capacitors (EDLCs). The relatively open morphology of the films provided good frequency response, but had limited capacitance compared to present day activated carbon EDLCs. The objective of this research was to improve the capacitance of these films to a commercially viable level while maintaining sufficient frequency response for AC filtering. The growth of VOGN on Ni and Al substrates has been studied in this work. The native oxide on Ni was thinned at temperatures above ~600ºC with the …