Matching Items (4)
Description
A system for illuminating a sample in situ with visible and UV light inside a transmission electron microscope was devised to study photocatalysts. There are many factors which must be considered when designing and building such a system. These include both mechanical, optical, and electron optical considerations. Some of the restrictions posed by the electron microscope column are significant, and care must be taken not to degrade the microscope's electron optical performance, or to unduly restrict the other current capabilities of the microscope. The nature of these various design considerations is discussed in detail. A description of the system that has been added to the microscope at ASU, an FEI Tecnai F20 environmental transmission electron microscope is also given. The system includes a high brightness broadband light source with optical filters, a fiber to guide the light to the sample, and a system for precisely aligning the fiber tip. The spatial distribution and spectrum of the light reaching the sample has been characterized, and is described in detail.
ContributorsMiller, Benjamin (Author) / Crozier, Peter A. (Thesis advisor) / McCartney, Martha (Committee member) / Rez, Peter (Committee member) / Arizona State University (Publisher)
Created2012
Description
Mixed reality mobile platforms co-locate virtual objects with physical spaces, creating immersive user experiences. To create visual harmony between virtual and physical spaces, the virtual scene must be accurately illuminated with realistic physical lighting. To this end, a system was designed that Generates Light Estimation Across Mixed-reality (GLEAM) devices to continually sense realistic lighting of a physical scene in all directions. GLEAM optionally operate across multiple mobile mixed-reality devices to leverage collaborative multi-viewpoint sensing for improved estimation. The system implements policies that prioritize resolution, coverage, or update interval of the illumination estimation depending on the situational needs of the virtual scene and physical environment.
To evaluate the runtime performance and perceptual efficacy of the system, GLEAM was implemented on the Unity 3D Game Engine. The implementation was deployed on Android and iOS devices. On these implementations, GLEAM can prioritize dynamic estimation with update intervals as low as 15 ms or prioritize high spatial quality with update intervals of 200 ms. User studies across 99 participants and 26 scene comparisons reported a preference towards GLEAM over other lighting techniques in 66.67% of the presented augmented scenes and indifference in 12.57% of the scenes. A controlled lighting user study on 18 participants revealed a general preference for policies that strike a balance between resolution and update rate.
To evaluate the runtime performance and perceptual efficacy of the system, GLEAM was implemented on the Unity 3D Game Engine. The implementation was deployed on Android and iOS devices. On these implementations, GLEAM can prioritize dynamic estimation with update intervals as low as 15 ms or prioritize high spatial quality with update intervals of 200 ms. User studies across 99 participants and 26 scene comparisons reported a preference towards GLEAM over other lighting techniques in 66.67% of the presented augmented scenes and indifference in 12.57% of the scenes. A controlled lighting user study on 18 participants revealed a general preference for policies that strike a balance between resolution and update rate.
ContributorsPrakash, Siddhant (Author) / LiKamWa, Robert (Thesis advisor) / Yang, Yezhou (Thesis advisor) / Hansford, Dianne (Committee member) / Arizona State University (Publisher)
Created2018
Description
Vivid illuminations of the aristocratic hunt decorate Bibliothèque nationale de France, MS. fr. 616, an early fifteenth-century illuminated manuscript of Le livre de chasse composed by Gaston Fébus, Count of Foix and Viscount of Béarn (1331-1391 C.E.), in 1389. Gilded miniatures visualize the medieval park, an artificial landscape designed to facilitate the ideal noble chase, depicting the various methods to pursue, capture, and kill the prey within as well as the ritual dismemberment of animals. Medieval nobles participated in the social performance of the hunt to demonstrate their inclusion in the collective identity of the aristocracy. The text and illuminations of Le livre de chasse contributed to the codification of the medieval noble hunt and became integral to the formation of cultural memory which served as the foundation for the establishment of the aristocracy as different from other parts of society in the Middle Ages. This study contributes new information through examination of previously ignored sources as well as new analysis through application of critical theoretical frameworks to interpret the manuscript as a meaning-making object within the visual culture of the Middle Ages and analysis of the illuminations reveals the complexities surrounding one of the most important acts of performance for the medieval elite.
ContributorsPratt-Sturges, Rebekah (Author) / Schleif, Corine (Thesis advisor) / Cruse, Markus (Committee member) / Cuneo, Pia (Committee member) / Arizona State University (Publisher)
Created2017
Description
One of the most pronounced issues affecting the management of fisheries today is bycatch, or the unintentional capture of non-target species of marine life. Bycatch has proven to be detrimental for many species, including marine megafauna and pelagic fishes. One method of reducing bycatch is illuminated gillnets, which involves utilizing the differences in biological visual capabilities and behaviors between species of bycatch and target fish catch. To date, all studies conducted on the effects of net illumination on bycatch and target fish catch have been conducted at night. In this study, the effects of net illumination on bycatch, target fish catch, and market value during both night and day periods at Baja California Sur, Mexico were compared. It was found that i) net illumination is effective (p < 0.05) at reducing bycatch of finfish during the day and at night, ii) net illumination at night is more effective (p < 0.05) at reducing bycatch for elasmobranchs, Humboldt squid, and aggregate bycatch than during the day, iii) time of day did not have an effect (p > 0.05) on sea turtle bycatch, and iv) net illumination did not significantly (p > 0.05)affect target catch or market value at night or during the day. These results suggest that net illumination may be an effective strategy for reducing finfish bycatch in fisheries that operate during the day or across 24 h periods, and is especially effective for reducing elasmobranch, Humboldt squid, and total bycatch biomass at night.
ContributorsDenton, Kyli Elise (Author) / Senko, Jesse (Thesis advisor) / Neuer, Susanne (Thesis advisor) / Pratt, Stephen (Committee member) / Arizona State University (Publisher)
Created2021