Physical Sciences and Mathematics Commons^™

Town Of Salisbury Harbor Plan -- Phase 1, Urban Harbors Institute, University Of Massachusetts Boston

Urban Harbors Institute Publications

This document presents information developed during the first phase of the planning process to develop a Harbor Plan for the Town of Salisbury, Massachusetts. The initial phase consists of compiling and mapping existing information on natural resources, uses of the waterways and shoreline, relevant government regulatory programs and jurisdictions, identifying issues, and conducting some analyses of recreational boating-related needs. A mooring plan and mooring field delineation plan are required by the Harbor Management Plan and will be periodically updated as needed. This phase concludes with a preliminary identification of long-term goals and the development of recommendations for next steps in …

Electron Tunneling In A Strained N-Type Si1−Xgex/Si/Si1−Xgex Double-Barrier Structure, K. M. Hung, T. H. Cheng, W. P. Huang, K. Y. Wang, H. H. Cheng, Greg Sun, R. A. Soref

Physics Faculty Publications

We report electrical measurements on an n-type Si_1−xGe_x/Si/Si_1−xGe_x double-barrier structure grown on a partially relaxed Si_1−yGe_y buffer layer. Resonance tunneling of Δ₄band electrons is demonstrated. This is attributed to the strain splitting in the SiGe buffer layer where the Δ₄ band is lowest in energy at the electrode. Since the Δ₄ band electrons have a much lighter effective mass along the direction of tunneling current in comparison with that of the Δ₂ band electrons, this work presents an advantage over those …

Electroluminescence Efficiency Enhancement Using Metal Nanoparticles, Jacob B. Khurgin, Greg Sun, R. A. Soref

Physics Faculty Publications

We apply the “effective mode volume” theory to evaluate enhancement of the electroluminescence efficiency of semiconductor emitters placed in the vicinity of isolated metal nanoparticles and their arrays. Using the example of an InGaN/GaN quantum-well active region positioned in close proximity to Ag nanospheres, we show that while the enhancement due to isolated metal nanoparticles is large, only modest enhancement can be obtained with ordered array of those particles. We further conclude that random assembly of isolated particles holds an advantage over the ordered arrays for light emitting devices of finite area.

Plymouth-Carver Sole Source Aquifer: Regional Open Space Plan, Urban Harbors Institute, University Of Massachusetts Boston

Urban Harbors Institute Publications

The second largest sole source aquifer in Massachusetts, the Plymouth-Carver Sole Source Aquifer (the Aquifer) covers 140 square miles underlying the towns of Plymouth, Carver, Kingston, Wareham, Plympton, Middleborough, and Bourne. The Aquifer contains over 500 billion gallons of fresh water (USGS 1992), and serves as a critical water resource for residential, commercial, and agricultural uses in the area. Though its resources are vast, they are not unlimited, nor are they unaffected by contamination.

On August 7, 1990, the Environmental Protection Agency (EPA) released a notice announcing that the Plymouth-Carver Aquifer satisfies all criteria for designation as a sole source …

An Application For A State Designated, Federally Approved No Discharge Area For Boston Harbor, Ma, City Of Boston Environment Department, City Of Quincy Harbormaster, Urban Harbors Institute, University Of Massachusetts Boston, Charles River Watershed Association

Urban Harbors Institute Publications

The municipalities surrounding Boston Harbor are requesting that the Commonwealth of Massachusetts designate the waters of Boston Harbor as a No Discharge Area (NDA) pursuant to the Clean Water Act, Section 312(f)(3). An NDA is a body of water in which the discharge of vessel sewage, whether treated or not, is prohibited. The No Discharge Area would be called the Boston Harbor No Discharge Area.

While the waters of Boston Harbor are under the jurisdiction of a number of different municipalities, water quality issues affect the harbor as a whole. Past efforts to clean up the harbor have occurred across …

Economists, Value Judgments, And Climate Change: A View From Feminist Economics, Julie A. Nelson

Economics Faculty Publication Series

A number of recent discussions about ethical issues in climate change, as engaged in by economists, have focused on the value of the parameter representing the rate of time preference within models of optimal growth. This essay examines many economists' antipathy to serious discussion of ethical matters, and suggests that the avoidance of questions of intergenerational equity is related to another set of value judgments concerning the quality and objectivity of economic practice. Using insights from feminist philosophy of science and research on high reliability organizations, this essay argues that a more ethically transparent, real-world-oriented, and flexible economic practice would …

Shading Facilitates Sessile Invertebrate Dominance In The Rocky Subtidal Gulf Of Maine, Ron J. Etter, Robert J. Miller

Biology Faculty Publication Series

Dramatic shifts in community composition occur between vertical and horizontal rocky surfaces in subtidal environments worldwide, yet the forces mediating this transition are poorly understood. Vertical rock walls are often covered by lush, diverse communities of sessile suspension-feeding invertebrates, while adjacent horizontal substrates are dominated by algae, or corals in the tropics. Multiple factors, including light, sedimentation, water flow, and predation have been proposed to explain this pattern, but experimental tests of these hypotheses are lacking. We manipulated light level and predation to test whether variation in these mechanisms could be responsible for the shift in composition of sessile communities …