Perylene and perylene diimide (PDIs) are widely used for organic optical electronic materials due to their outstanding thermal stability, visible light absorption and high molar absorption coefficients. To tailor perylene and PDI’s optical and electronic properties for specific applications, molecular contortion and bay-functionalization have been proved as effective methods. In this thesis, these strategies will be applied to perylene and PDI to develop novel optical and electronic materials. In the first chapter, the molecular contortion strategy is applied to perylene to tune singlet and triplet energies and successfully turn on singlet fission in thin films of contorted perylene. Perylene does not undergo singlet fission in its planar form. The tuning of the energetics that control singlet fission through molecular contortion can be applied to a large repertoire of established molecular chromophores. In the second chapter, novel bay-functionalization reactions of PDI, which are base-assisted direct amination and N-heteroarylation, are discussed. The reactions are able to achieve up to 70% yield for mono N-heteroarylation. UV-Vis and EPR spectroscopy suggest that these reactions are mediated through PDI radical anions that are thermally induced by strong bases. An intriguing small-molecule white-light-emitter is constructed from this reaction. In the third chapter, contorting PDIs to form chiral helicenes for Chiral Induced Spin Selectivity (CISS) is discussed. CISS allows for selective transportation of one electron spin and filtration out of the other spin, exhibiting great potential applications in spintronics, spin-polarized light-emission, and spin-controlled catalysis. However, the mechanism of CISS remains unclear and it is necessary to develop a molecular system that allows for the investigation of CISS effect at the atomic level. PDI-based helicenes could be an ideal model system for the investigation of CISS effect due to their chiroptical properties. The chirality of PDI-based helicene dimers is resolved without chiral HPLC separation by converting helicene enantiomers into diastereomers, where Prep TLC is used to separate the helicene diastereomers at a relatively large scale.

Phytoplankton populations are integral to the structure and function of aquatic ecosystems, and phytoplankton are an excellent study system for exploring ecological questions. Reservoirs often exhibit high horizontal (inflow to dam) and vertical (surface to sediments) environmental heterogeneity, which plays a large role in determining phytoplankton population dynamics. In this thesis, I explore how three bloom-forming phytoplankton taxa, the dinoflagellates Peridinium and Gymnodinium, and the cyanobacterium Planktothrix, respond to horizontal and vertical environmental gradients, respectively. First, I monitored recruitment, or the process of leaving the sediments and entering the pelagic life stage, of dinoflagellates across a horizontal reservoir ecosystem gradient. Surprisingly, coupling of dinoflagellate biology with reservoir physics and chemistry varied along this continuum; recruiting cells were sensitive to reservoir physics (e.g., flow rate, solar radiation) in the upstream riverine zone, while recruitment was related to reservoir chemistry (e.g., dissolved oxygen, nutrients) in the downstream lacustrine zone. This study indicates that upstream habitats should be monitored when studying reservoir phytoplankton dynamics. Next, I investigated the environmental drivers of the vertical distribution and biomass of a hypolimnetic cyanobacterial bloom over two consecutive summers. I collected high-resolution in situ phytoplankton data, and measured environmental variables throughout the water column. Across both years, the vertical distribution of this population was determined by light availability, while the cyanobacterial biomass was predicted by both light and nutrients. These two studies demonstrate that changing physics and chemistry across environmental gradients can regulate phytoplankton dynamics in reservoirs, and phytoplankton monitoring should include more spatially comprehensive sampling approaches. / Master of Science

Active daylight harvesting technologies that are currently available in the market have often suffered from wide-spread market acceptability due to their high cost and imperfect performance. Passive systems, though simple and affordable, typically cannot harvest higher potentials of daylight, which is dynamic over days, months, and seasons, due to their static nature. There is a research and market gap that calls for investigation towards the development of low-tech, manually adjustable, high-performance daylighting mechanisms to be used as an alternative to active daylighting solutions, which are often controlled by building automation systems. This research proposes a framework to support the development of daylight harvesting mechanisms, which will allow for low-tech yet temporary adjustable systems, merging some of the advantages of active systems with passive ones. The hybrid of the above two categories will be a manually adjustable light harvesting device that will allow for quick adjustment through mechanical means to few predefined positions. These positions will be customized to each location to achieve optimum daylight harvesting. The resulting device will allow for flexible adjustment to daily and seasonal variations of the sun's path, while retaining a level of simplicity and elegance towards low-cost installation and operation. Significant effort was made in the initial phase of this research to use experimental studies as the primary method of investigation. However, given the nature of daylight and practical constraints in the field, the experimental method was found to be not productive enough for extent of this research. As a result, simulation studies were ultimately used to generate the necessary data for the development of this framework. For the simulation phase 'DIVA4Rhino,' a climate-based daylighting software and 'Grasshopper,' a graphical programming tool for Rhino, was used to first construct a parametric simulation loop. Next, a reduced set of parameters for a manually adjustable light shelf system were tested for daylight performance, as a 'proof of concept'. Finally, based on the previous two steps, a framework to help the development of manually adjustable light shelf systems has been defined. This research shows that light shelves, even when kept fixed at a single optimum configuration for the whole year, can increase interior daylight performance in most locations and orientations. It also shows that indoor daylight harvesting can be further enhanced if the light shelf is manually adjusted on a seasonal basis. Amongst the variations tested, rotational adjustability has been found to contribute most to the increase in performance. Segmented adjustability, e.g. where the inner and outer sections of a light shelf are manipulated separately, was found to extend performance of light shelves even further though not by significant amounts. / Ph. D.

The stage of maturity of seeds at harvest is an important factor that determines seed vigor. Separating seeds from a seed lot composed of many different stages of development can be difficult especially after maximum dry mass is attained. Separating seeds based on their physiological maturity is more challenging than sorting seeds based on their physical properties. Seeds may be non-destructively sorted using chlorophyll fluorescence (CF) as a marker of seed maturity. This study was conducted to test whether CF could be used to remove low vigor immature seeds from muskmelon (Cucumis melo L.'Top Mark') and tomato (Lycopersicum esculentum) seed lots. Light treatments were applied to determine whether the light environment during seed harvesting and processing could affect chlorophyll content and seed vigor. Seeds from nine stages of development were collected from 'TopMark'. Seeds from three stages of fruit development (red ripe, breaker, and mature green) were harvested from tomato cultivar Money Maker and two phytochrome mutants: phytochrome A mutant, fri-1 and phytochrome B mutant, tri-1. The SeedMaster Analyzer (Satake USA Inc., Houston Texas) was used to measure CF and to sort individual seeds according to CF levels. Immature tomato seeds and muskmelon, harvested from green fruits, had the highest CF (p>0.001). Contrary to the results obtained with the other tomato genotypes, the vigor of tri-1 did not change inversely with changing CF levels, rather, seeds with low CF had the same vigor as seeds with high CF. This result may suggest that the presence of phytochrome B exerts an inhibitory influence on vigor in tomato seeds, and that the persistent presence of chlorophyll during seed development does not affect vigor. The light treatments had no consistent effect on seed chlorophyll content or on vigor in either tomato or muskmelon. / Master of Science

A spatial sequence unfolds and is revealed over time. It is perceived through motion, movement channeled through the space with light and form. The layering and overlapping of surface creates a relationship of light and dark between preceding and receding forms. Light gives depth to this space and allows mass to convey light and dark. It is the mass, growing from the inside surface, that shapes the voids and frames the solids of the following space; solids which are transparent and are of void and light. Individual spatial configurations overlap to compose a whole, on experience of form orchestrated by light and light's darkness. / Master of Architecture

This thesis is an exploration of the historical, societal, and individual as well as material factors that contribute to the constructing of space, and in particular, sacred space. With the idea that the making of sacred space is simultaneously a material construct and a construct of the mind, both postures were considered and studied throughout the research and design process of the thesis. / Master of Architecture

M.S.

Master of Science

This project will address light use in a museum. The focus and the program will require give and take in order to provide sources of natural light without compromising conservation standards. The building will house exhibits of film and photography, including theatres, dark rooms, prints, and projections as well as all the necessary program to support the building including a cafeteria, restrooms, a gift shop, as well as indoor and outdoor gathering spaces. The building site is in DC. When choosing a site I consulted with the National Capital Planning Commission's urban plan of Washington. They have published on their website a study that has listed the city's potential monument and museum sites. When evaluating these sites I decided to use views to and from the sites, as well as acreage to dwindle down the options. / Master of Architecture

Keratin is a biomaterial derived from biological sources and can be used in a variety of medical applications. This study focuses on keratin derived from human hair. Unfortunately, there is not a lot of information in the literature describing how keratin reacts to subtle changes in an aqueous solution such as differences in pH, keratin concentration, buffer concentration, salt concentration, and temperature. To have a better understanding of this effect, dynamic light scattering was used to test the size ranges and volume percentages in each range. Dynamic light scattering shows the size of the keratin in each environment and its consistency with time. The results showed that there is a difference in keratin behavior between water and buffer solutions, but very subtle differences between each buffer, buffer concentration, keratin concentration, pH and temperature. Keratins aggregate extensively in un-buffered conditions (i.e. pure water), which has implications to both purification and fabrication of biomaterials as water is used extensively in these processes. Interestingly, there was little effect of keratin concentration, pH, and temperature on the buffers used in this study, suggesting there may be a wide range of conditions in which aggregation can be minimized. / Master of Science