Monte Carlo Investigation of Lattice Models of Polymer Collapse in Five Dimensions

Monte Carlo simulations, using the PERM algorithm, of interacting self-avoiding walks (ISAW) and interacting self-avoiding trails (ISAT) in five dimensions are presented which locate the collapse phase transition in those models. It is argued that the appearance of a transition (at least) as strong as a pseudo-first-order transition occurs in both models. The values of various theoretically conjectured dimension-dependent exponents are shown to be consistent with the data obtained. Indeed the first-order nature of the transition is even stronger in five dimensions than four. The agreement with the theory is better for ISAW than ISAT and it cannot be ruled out that ISAT have a true first-order transition in dimension five. This latter difference would be intriguing if true. On the other hand, since simulations are more difficult for ISAT than ISAW at this transition in high dimensions, any discrepancy may well be due to the inability of the simulations to reach the true asymptotic regime.Comment: LaTeX file, 16 pages incl. 7 figure

630-mV open circuit voltage, 12% efficient n-Si liquid junction

We report the first experimental observation of a semiconductor/liquid junction whose open circuit voltage Voc is controlled by bulk diffusion/recombination processes. Variation in temperature, minority-carrier diffusion length, and/or in majority-carrier concentration produces changes in the Voc of the n-Si/CH3OH interface in accord with bulk recombination/diffusion theory. Under AM2 irradiation conditions, the extrapolated intercept at 0 K of Voc vs T plots yields activation energies for the dominant recombination process of 1.1–1.2 eV, in accord with the 1.12-eV band gap of Si. A crucial factor in achieving optimum performance of the n-Si/CH3OH interface is assigned to photoelectrochemical oxide formation, which passivates surface recombination sites at the n-Si/CH3OH interface and minimizes deleterious effects of pinning of the Fermi level at the Si/CH3OH junction. Controlled Si oxide growth, combined with optimization of bulk crystal parameters in accord with diffusion theory, is found to yield improved photoelectrode output parameters, with 12.0±1.5% AM2 efficiencies and AM1 Voc values of 632–640 mV for 0.2-Ω cm Si materials

The Lake Champlain Basin Science Center : a flagship project in the Burlington Waterfront Revitalization

As stated in the thesis project, "For more than a decade now, the City of Burlington has fought for community access and control over one of the City's most important assets - the Lake Champlain waterfront. At the heart of the waterfront, isolated behind barbed wire fence, sits the U.S. Navy Reserve Center. The facility is used one weekend each month and otherwise remains dormant and locked. For more than ten years, the City has pursued relocating the Navy to open up the site for public use. Finally, in 1995 we are on the brink of converting this underutilized building to a Lake Champlain Basin Science Center--a dynamic, hands-on museum dedicated to demonstrating the ecology, history and culture of the Lake Champlain basin. By better understanding our past -- how Lake Champlain has affected human activity and how our actions have impacted the lake, we can make better choices for our future. The Science Center serves as a flagship project for the entire Burlington waterfront revitalization, cementing our goal of public access for ALL residents to this spectacular resource. Although the ultimate goal for the Lake Champlain Basin Science Center is a ribbon cutting on New Years 1997, much progress has been made in the last 17 months. In between writing up my final project and completing the 501(c)(3) application to the IRS to incorporate the new organization, we have a signed conceptual agreement between the City of Burlington, the University of Vermont and the Science Center Board. We have a capital campaign underway in its quiet stages with our sights set on launching a public splash this summer. We have moved 180 degrees from creating two separate facilities of research and a museum into one integrated museum where the research itself becomes an exhibit interpreted for a public audience. We have better defined the scope of the Science Center's program, at least conceptually. Our plan is to integrate the ecology, culture and history of the Lake Champlain Basin into a program that will teach all age visitors about how the Basin was formed, how we have come to know this, and what our place is within it. We have successfully secured a U.S. Department of Housing and Urban Development grant to buy the City out of the project and cover the City's debt so that the non-profit will no longer be strapped with an annual debt. We have completed conceptual drawings for a brand new 40,000 square foot facility, and have received nothing but positive responses from many different groups in the community about the project thus far. We have two part-time staff people, including myself, hired to keep the project moving." (Library-derived description)Rosenbluth, B. (1995). The Lake Champlain Basin Science Center: A flagship project in the Burlington Waterfront RevitalizationMaster of Science (M.S.)School of Community Economic Developmen