593 research outputs found
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Stable Cyclopropenium-Based Radicals
Stable radicals have enjoyed widespread use in a variety of fields including synthetic chemistry, materials chemistry, energy storage, and biochemistry. This thesis outlines our investigations of cyclopropenium-based stable radicals and their application as redox mediators, redox-active ligands, catalysts, and materials for energy storage.
The first chapter gives a brief overview of the use of radicals in synthetic chemistry. The principles that govern the stability of radicals is discussed and notable examples are highlighted. The second section of the first chapter reviews the aromatic platforms that have been developed by the Lambert group and how they might be converted into stable radical species.
The second chapter details our study of 2,3-diaminocyclpropenones as stable radicals. These electron rich cyclopropenium derivatives undergo facile oxidation to yield a radical cation species. The origin of the stability of this oxygen-centered radical was elucidated by density functional theory calculations and analysis of the crystal structure. Diaminocyclopropenones were also found to be effective neutral L-type ligands in Ce(IV) complexes. EPR and UV-VIS experiments revealed that these complexes exhibited reversible homolytic dissociation of their diaminocyclopropenone ligands.
The third chapter describes the use of trisaminocyclopropeniums as catholytes for nonaqueous redox flow batteries. A newly designed trisaminocyclopropenium structure could be accessed in large quantities and showed long lasting stability in its oxidized state. A new composite polyionic material was developed for use as a membrane suitable for organic solvent and high voltages. Cycling in combination with a perylenediimide anolyte yielded a 1.7 V battery that exhibited excellent coulombic efficiency and capacity retention. Using a spiro-bis(phthalimido) anolyte afforded a battery with an open circuit voltage of 2.8 V.
The fourth chapter details how our battery studies with trisaminocyclopropenium radical dications led us to discover their photoinduced reactivity. We developed an electrophotocatalytic platform using trisaminocyclopropeniums as a species capable of being activated by both photochemical and electrochemical energy. The excited state oxidation potential of the doubly activated species was found to be +3.33 V, which was capable of effecting oxidative coupling reactions using both arenes and ethers as substrates. Density functional theory calculations and spectroscopic experiments revealed that the photoreactivity was due to a SOMO-inversion event. The trisaminocyclopropenium radical dication could be prepared on scale via direct electrolysis and subsequently used in high throughput screening
Development of high resolution simulations of the atmospheric environment using the MASS model
Numerical simulations were performed with a very high resolution (7.25 km) version of the MASS model (Version 4.0) in an effort to diagnose the vertical wind shear and static stability structure during the Shuttle Challenger disaster which occurred on 28 January 1986. These meso-beta scale simulations reveal that the strongest vertical wind shears were concentrated in the 200 to 150 mb layer at 1630 GMT, i.e., at about the time of the disaster. These simulated vertical shears were the result of two primary dynamical processes. The juxtaposition of both of these processes produced a shallow (30 mb deep) region of strong vertical wind shear, and hence, low Richardson number values during the launch time period. Comparisons with the Cape Canaveral (XMR) rawinsonde indicates that the high resolution MASS 4.0 simulation more closely emulated nature than did previous simulations of the same event with the GMASS model
Product Architecture and Strategic Positioning in Information Products Firms
Businesses exist to deliver desired products and servicesto their markets. The efficient and effective design and development of products meeting market needs is a critical process which must be performed and managed effectively for a firm to remain viable. Product design and development has been dealt with at some length in the literature with regard to the architecture of assembled tangible products (e.g., automobiles (Abernathy 1978), power tools (Lehnerd 1987), production equipment (Henderson and Clark 1990), and computers (Meyer and Roberts 1988)), and process design for non-assembled tangible products (e.g., glass (Utterback 1994)). Less attention has been paid to the architecture for the delivery of services (Chase and Hayes 1991, Harvey and Filiatrault 1991, Heskett 1993, Heskett and Schlesinger 1994), and almost no research has been done with regard to the design and delivery of information 1 products and services. The worldwide economy is shifting from one based predominantly on physical goods and energy to one based on information goods and knowledge. Yet we do not understand much about the transformation to an information-based economy comprising firms whose core competency is their ability to create, access, or add value to information. This paper focuses on the effective design of information products. It develops a framework for organizing, managing, and building a robust information technology platform for the effective design and develop of information-based products and services. Based on that framework, we develop a means for assessing the strategic positioning and defensibility of information products firms
THE IMPACT OF MARKETING INFORMATION SUPPLY ON PRODUCT MANAGERS: AN ORGANIZATIONAL INFORMATION PROCESSING PERSPECTIVE
This paper examines the impact of information supply and distribution on managerial information processing using a model derived from the organizational information processing (OIP) framework developed by Daft and Weick (1984). The model suggests that more supply and distribution of information wiltlead to greater information use and the acquisition of more knowledge, given the organization\u27s information processing capabilities match its requirements. The model was extended to include the influence of social factors (i. e., culture and power) and the level of knowledge in the organization. Product managers in two consumer goods organizations providing different levels of information technology support were studied to compare the effect of different approaches to supplying and distributing information. The focused comparison case research method (George and McKeown 1985) was used, in which sites are selected differing only on the dimensions of interest, namely information supply and distribution. The cases provided evidence to support the model. The company which had more data and analytic tools available for its product managers used more information and knew more about the factors that influenced the marketing of its products. In addition, organizational culture and the level of knowledge at the companies affected their approach to information supply, information use, and knowledge acquisition. The results suggest that the effective use of information technology requires a combination of managing the organization culture and fitting the characteristics of information supply and distribution mechanisms to information requirements
Model AI Assignments 2018
The Model AI Assignments session seeks to gather and disseminate the best assignment designs of the Artificial Intelligence (AI) Education community. Recognizing that assignments form the core of student learning experience, we here present abstracts of seven AI assignments from the 2018 session that are easily adoptable, playfully engaging, and flexible for a variety of instructor needs. Assignment specifications and supporting resources may be found at http://modelai.gettysburg.edu
From principles to action: Applying the National Research Council's principles for effective decision support to the Federal Emergency Management Agency's watch office
AbstractThe National Research Council (NRC) proposed six principles for effective decision support in its 2009 report Informing Decisions in a Changing Climate. We structured a collaborative project between the Federal Emergency Management Agency Region R9 (FEMA R9), the Western Region Headquarters of the National Weather Service (WR-NWS), and the Climate Assessment of the Southwest (CLIMAS) at the University of Arizona around the application of the NRC principles. The goal of the project was to provide FEMA R9's Watch Office with climate information scaled to their temporal and spatial interests to aid them in assessing the potential risk of flood disasters. We found that we needed specific strategies and activities in order to apply the principles effectively. By using a set of established collaborative research approaches we were better able to assess FEMA R9's information needs and WR-NWS's capacity to meet those needs. Despite our diligent planning of engagement strategies, we still encountered some barriers to transitioning our decision support tool from research to operations. This paper describes our methods for planning and executing a three-party collaborative effort to provide climate services, the decision support tool developed through this process, and the lessons we will take from this deliberate collaborative process to our future work and implications of the NRC principles for the broader field of climate services
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