Yes / We report on the use of non-equillibrium biocatalytic self-assembly and gelation to guide the reductive synthesis of gold nanoparticles. We show that biocatalytic rates simultaneously dictate supramolecular order and presentation of reductive phenols which in turn results in size control of nanoparticles that are formed. / BBSRC funding (BB/K007513/1); European Research Council under the European Union’s Seventh Framework Programme, ERC (Starting Grant EMERgE) grant agreement no. 258775.

Quantum dot infrared photodetectors (QDIPs) have emerged as a promising technology in the mid- and far-infrared (3-25 μm) for medical and environmental sensing that have a lot of advantages over current technologies based on Mercury Cadmium Telluride (MCT) and quantum well (QW) infrared photodetectors (QWIPs). In addition to the uniform and stable surface growth of III/V semiconductors suitable for large area focal plane applications and thermal imaging, the three dimension confinement in QDs allow sensitivity to normal incidence, high responsivity, low darkcurrent and high operating temperature. The growth, processing and characterizations of these detectors are costly and take a lot of time. So, developing theoretical models based on the physical operating principals will be so useful in characterizing and optimizing the device performance. Theoretical models based on non-equilibrium Green's functions have been developed to electrically and optically characterize different structures of QDIPs. The advantage of the model over the previous developed classical and semiclassical models is that it fairly describes quantum transport phenomenon playing a significant role in the performance of such nano-devices and considers the microscopic device structure including the shape and size of QDs, heterostructure device structure and doping density. The model calculates the density of states from which all possible energy transitions can be obtained and hence obtains the operating wavelengths for intersubband transitions. The responsivity due to intersubband transitions is calculated and the effect of having different sizes and different height-to-diameter ratio QDs can be obtained for optimization. The dark and photocurrent are calculated from the quantum transport equation provided by the model and their characteristics at different design parameter are studied. All the model results show good agreement with the available experimental results. The detectivity has been calculated from the dark and photocurrent characteristics at different design parameters. The results shows a trade off between the responsivity and detectivity and what determines the best performance is how much the rate of increase of the photocurrent and dark current is affected by changing the design parameters. Theoretical modeling developed in the thesis give good description to the QDIP different characteristics that will help in getting good estimation to their physical performance and hence allow for successful device design with optimized performance and creating new devices, thus saving both time and money. / Thesis / Doctor of Philosophy (PhD)

Origin-Destination (O-D) trip tables represent the demand-supply information of each directed zonal-pair in a given region during a given period of time. The effort of this research is to develop a linear programming methodology for estimating O-D trip tables based on observed link volumes. In order to emphasize the nature of uncertainty in the data and in the problem, the developed model permits the user's knowledge of path travel time to vary within a band-width of values, and accordingly modifies the user-optimality principle. The data on the observed flows might also not be complete and need not be perfectly matched. In addition, a prior trip table could also be specified in order to guide the updating process via the model solution. To avoid excessive computational demands required by a total numeration of all possible paths between each O-D pair, a Column Generation Algorithm (CGA) is adopted to exploit the special structures of the model. Based on the known capacity of each link, a simple formula is suggested to calculate the cost for the links having unknown volumes. An indexed cost is introduced to avoid the consideration of unnecessary passing-through-zone paths, and an algorithm for solving the corresponding minimum-cost-path problem is developed. General principles on the design of an object-oriented code are presented, and some useful programming techniques are suggested for this special problem. Some test results on the related models are presented and compared, and different sensitivity analyses are performed based on different scenarios. Finally, several research topics are recommended for future research. / Master of Science

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