Integrated circuit control of resonant and hard switched dc/dc converters for industrial and educational applications

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 127-128).This thesis presents an integrated secondary side synchronous rectification controller, designed on a modern industrial silicon IC process, for use in the LLC resonant converter topology. The controller is intended to function in systems with output power levels up to 500 W and switching frequencies up to 1 MHz. Simulation data for this controller indicates high degrees of performance over a input voltage range of 12-48 V and an operating temperature range of -50° C to 150° C. Significant improvement over existing synchronous rectication controllers is observed. In addition, a simulation and written exercise framework, intended to couple with circuits in a pre-existing discrete hardware kit, has been developed for a proposed class on power IC design. SPICE schematics of important circuit modules as well as relevant coursework is presented and explained. The course itself is motivated by the challenges of the industrial design process, and goals include teaching students about practical power IC design techniques and developing their intuition for high level circuit function. The end result is student construction of a working controller for a traditional hard-switched dc/dc converter.by Victor Samuel Sinow.M.Eng

Academic Hiring Gatekeeper & Employer Perceptions Of Online Degrees And The Acceptability Of Online Degrees For Faculty And Administrator Employment In Higher Education

Due to its flexibility and convenience, online education has become a feasible alternative for degree seeking students who are unable to attend a traditional higher education institution. Although online courses and programs have their benefits, there remains an ongoing debate on issues related to credibility, quality, and acceptability among certain stakeholders including faculty, administrators, and employers. The current study focuses on one group of academic stakeholders-namely, academic hiring gatekeepers and employers; that is, those who are directly involved in the hiring process of faculty and administrators. Specifically, the objective is to explore hiring gatekeeper and employer acceptability of online degrees as a sufficient credential for employment in institutions of higher education. While there are many assumptions and commonly held perceptions in the academic community regarding the value and quality of online degrees, the purpose of this study is to simply describe these views and attitudes. The data for this study were collected primarily through in-depth interviews and a survey apparatus that was implemented online. The overall design proposed for this study was grounded in the mixed-methods approach to data collection (Creswell, 2003). Data gathered from 102 surveys was examined using ANOVA and Chi-Square analysis and the statistical relevance of the findings suggest that within higher education, there continues to be a robust debate among academic hiring gatekeepers in higher education regarding the quality and rigor associated with online degrees. Moreover, study findings also reveal that academic hiring gatekeepers perceptions of online degrees do influence the hiring practices for positions. Finally, data from the in-depth interviews demonstrates that institutional reputation was a critical factor when making faculty and administrator hiring decisions

Substantial chest-wall deformity following tissue expansion after radiotherapy

We present the case of a 54-year-old woman who underwent a two-stage breast reconstruction with a tissue expander after sustaining a lumpectomy and local radiotherapy for breast cancer. During expansion, the woman developed an abnormal concave deformity of the chest wall. Although respiratory or aesthetic consequences were expected, our patient reported only pain and was satisfied with the end result. Osteoporosis or local recurrence was excluded as predisposing factors, and radiotherapy was considered to be the causal factor in our patient. On the basis of this finding, we advise surgeons to take the risk of chest-wall deformity into consideration when planning a reconstruction with tissue expanders, especially in patients with a history of radiotherapy, and we recommend an alternative reconstructive method in this group of patients

The Foreign Corrupt Practices Act of 1977

178 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1982.In 1977, the 95th Congress of the United States passed and President Jimmy Carter signed into law, the Foreign Corrupt Practices Act, Public Law 95-213. The general purpose of this Act is to make it unlawful for publicly held corporations to make certain payments to foreign officials and other foreign persons with the specific intent to influence the foreign official's behavior.Far from being a routine or insignificant item of legislation, this law broke new ground by attempting to regulate U.S. corporate behavior outside its borders. The circumstances surrounding the Act's formulation, the political climate which facilitated its passage, and the speed with which the opposition mobilized to hinder its implementation and enforcement, are therefore all worthy of study--not only for what they may tell the reader about the Act itself, but also for insights they provide into four broader theoretical issues: (1) To what extent can a study of the Act aid the reader in examining the nature and structure of the political process by which foreign policy is formulated? (2) To what extent can foreign policy making be viewed primarily as a response to external (foreign) stimuli? (3) What should be the economic relationship between a multinational corporation and its home country? (4) To what extent can the U.S. impose foreign business policy by and through the enactment of the Foreign Corrupt Practices Act?After examining the aforementioned theoretical issues, one can conclude that there are at least three factors which contribute to an effective foreign business policy. First, the policy must be countenanced by the major political actors in the political system. In other words, a true consensus should exist. Second, the policy must be responsive to the interdependent domestic and foreign dimensions which initially gave rise to the policy. And third, the policy must equitably regulate foreign economic opportunities.It is this author's position that the Foreign Corrupt Practices Act of 1977 fails all three of the above criteria, and the Act has far more dramatically affected the American political system than any of the political systems where U.S. firms conduct international business.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

A Step Beyond BRET: Fluorescence by Unbound Excitation from Luminescence (FUEL)

Fluorescence by Unbound Excitation from Luminescence (FUEL) is a radiative excitation-emission process that produces increased signal and contrast enhancement in vitro and in vivo. FUEL shares many of the same underlying principles as Bioluminescence Resonance Energy Transfer (BRET), yet greatly differs in the acceptable working distances between the luminescent source and the fluorescent entity. While BRET is effectively limited to a maximum of 2 times the Förster radius, commonly less than 14 nm, FUEL can occur at distances up to µm or even cm in the absence of an optical absorber. Here we expand upon the foundation and applicability of FUEL by reviewing the relevant principles behind the phenomenon and demonstrate its compatibility with a wide variety of fluorophores and fluorescent nanoparticles. Further, the utility of antibody-targeted FUEL is explored. The examples shown here provide evidence that FUEL can be utilized for applications where BRET is not possible, filling the spatial void that exists between BRET and traditional whole animal imaging