The ribosome, the cell’s machine for synthesizing proteins, can be thought of as the chef of the cell. Just as a chef reads a recipe and combines ingredients to create a dish, the ribosome reads cellular instructions and connects building block molecules (amino acids) to construct proteins. Like the final...
The purpose of the dissertation is to develop a framework for equilibration of activity-trip chain demand in an integrated system of activity scheduling and travel choices within a dynamic network equilibrium framework. Activity-based modeling systems generate detailed activity chain schedules for individuals, which have to be assigned to transportation networks....
Pattern recognition algorithms have been proposed as a way to control powered lower limb prostheses, specifically for transitioning between the different pre-programmed locomotion modes of the prosthesis (e.g., level ground walking, stair ascent, etc.). However, these algorithms cannot track changes in the statistical characteristics of input signals, and do not...
The rapid growth of digital imaging technology and the accumulation of large collections of digital images has created the need for efficient and intelligent schemes for content-based image retrieval. Our goal is to organize the contents semantically, according to meaningful categories. We present a new approach for semantic classification that...
The optical and magneto-optical properties of the ferromagnetic semiconductors, InMnAs and its alloy InMnAsP were investigated to determine the band structure and nature of the ferromagnetism in these materials. Alloys were grown by metal-organic vapor phase epitaxy. Infrared absorption of InMnAs was investigated to determine the presence and properties of...
Ceramic matrix composites are known for their low density, high strength and high stiffness, but lower fracture toughness compared to metal matrix composites. The addition of a reinforcing agent within the matrix can increase the toughness of the composite via many strain energy absorption mechanisms such as plastic deformation. This...
Substrate-mediated delivery involves the immobilization of DNA, complexed with nonviral vectors, to a biomaterial or surface that supports cell adhesion. Cells cultured on the substrate are exposed to elevated DNA concentrations within the local microenvironment, which enhances transfection. As surface properties are critical to this delivery approach, self-assembled monolayers (SAMs)...
Autoxidation is a primary route by which lubricants in working conditions undergo degradation. Degraded lubricants, if not replaced periodically, contribute to increased wear and product failure. Experimental studies of lubricant degradation have yielded useful results but have left important questions unanswered. While many computational studies of degradation have been carried...
In composite manufacturing, Vacuum Assisted Resin Transfer Molding (VARTM) is becoming increasingly important as a cost effective manufacturing method of structural composites. In this process the dry preform (reinforcement) is placed on a rigid tool and covered by a flexible film to form an airtight vacuum bag. Liquid resin is...
Next generation of high performance nano-optoelectronic integrated circuits will require an integral combination of highly efficient all-optical nanophotonic devices and electrically-pumped nanophotonic devices, which will enable the chip to process optical information all optically with ultrafast speed and electro-optically to interface with the electronic control plane. The realizations of such...
As technology moves into deep submicron and nanoscale era, undesirable trends such as increasing power density, leakage power, and temperature variation within chips have made thermal effects emerge as a major bottleneck in further technology scaling. Thermal effects are no longer considered as just a reliability issue, but it also...
This dissertation examines the impact of product returns on effective supply chain management. Within this area of research, known as Closed-Loop Supply Chain Management, we consider both strategic and tactical level reverse logistics and inventory management problems from the perspective of a firm which must efficiently process returned items. More...
Oxide surface structures play a key role in many technological processes, including catalysis, thin film growth, and layered structures, and a thorough understanding of surface structures and surface structure dynamics is required in order to better engineer materials systems for these processes. This research works towards understanding these fundamental principles...
Structural dynamics in three polymer blend systems, differing largely with respect to morphology, have been investigated. The first system, composed of two immiscible homopolymers, exhibits a microstructure of micron-sized droplets dispersed in a matrix phase. We have examined small-angle x-ray scattering (SAXS) as a new approach for conducting in situ...
Living organisms grow precisely controlled assemblies of inorganic crystals using organic substrates. This observation has inspired the strategy of using synthetic organic templates for the growth of tailored inorganic thin films. It has been previously shown that monomolecular organic layers floating on supersaturated aqueous subphases (Langmuir monolayers) select the structure...
The self-assembly of quantum dots (QDs) in thin solid films is an important area of nanotechnology with many relevant applications. In the present thesis, three problems related to the growth and self-assembly of QDs are investigated.
In Chapter 1, a new instability mechanism for the formation of QDs associated with...
Dimensionally constrained material systems are at the forefront of current materials research because of their novel and often enhanced physical, chemical and biological properties. The dimensionality effects are pervasive through different classes of materials including ceramics, metals and polymers. Often times dimensionality effects are manifested as internal structure variations in...
The work presented in this dissertation focuses on ceramic anode materials for solid oxide fuel cells (SOFCs). The primary goal was to characterize the anode and relate the electrochemical behavior to the microstructure. The anode that was most extensively studied in this work was a composite of Gd0.10Ce0.90O1.95 (GDC) and...
Granular matter and living cells represent two extremes of what have come to be regarded as complex systems - systems characterized by a richness in global behavior that is not easily deduced from the interactions of their individual parts, even when those interactions are simple and well understood. On the...
This dissertation demonstrates how self-assembly can direct nanoscale ordering and optimize electronic properties of organic semiconductors, as well as organic-inorganic hybrids. In excitonic solar cells, controlling the ordering and interfaces between electron-transporting (n-type) and hole-transporting (p-type) domains is crucial. In addressing this challenge, hybrid nanostructures were designed by mineralization of...