Using GIS to Quantify Patterns of Glacial Erosion on Northwest Iceland: Implications for Independent Ice Sheets

Glacial erosion patterns on northwest Iccliind are quantified using a Geographic Information System (GIS) in order to interpret subglacial characteristics of part of northwest Iceland affected by ice sheet glaciation. Ice scour lake density is used as a proxy for glacial erosion. Erosion classes are interpreted from variations in the density of lake basins. Lake density was calculated using two dilTerent methods: the first is sensitive to the total number of lakes in a specific area, and the second is sensitive to total lake area in a specific area. Both of these methods result in a value for lake density, and the results for lake density calculated using the two methods are similar. Areas with the highest density of lakes are interpreted as areas with the most intense erosion with the exception of alpine regions. The highest density of lakes in the study area exceeds 8% and is located on upland plateaus where mean elevations range from 400 to 800 m a.s.l. Low lake density (0-2%) is observed in steep alpine areas where steep topography does not favor lake development. The G!S analysis is combined with geomorphic mapping to provide ground truth for the GIS interpretations and to locate paleo-ice flow indicators and landforms. The patterns identified in this study illustrate distinct regions of glacial erosion and flow paths that are best explained by two independent ice sheets covering northwest Iceland during the Last Glacial Maximum (LGM). Areas of alpine glacial landforms and the presence of nunataks within the glaciated region support interpretations that Ice-free regions or cold-based ice cover existed on parts of northwest Iceland during the LGM. The methods developed in this study are easily transferable to other formerly glaciated regions and provide tools to evaluate subglacial properties of former ice sheets. The data generated yield important subglacial boundary conditions for ice sheet models of Iceland

Graduate Internship Report in AgEd: Heritage High School

This document represents a compilation of responses addressing the Quality Criteria in Agricultural Education, and the required documentation. The forty-eight sections of this document cover the following three major areas. Heritage High School\u27s program information in meeting the Quality Criteria in Agricultural Education. Verification and supporting documentation in meeting the quality criteria. Project emphasis repor

Cool Roofs at Pomona College

The energy efficiency of a building is directly related to the heat transfer between the building and the outside environment. In order to limit the heat transfer to the building by solar radiation cool roofs have been developed which increase the solar reflectivity of roofs. This report investigates the potential application of high reflectivity coatings to roofs at Pomona College and the energy benefits that could result. Cool roofs are used to address two prevalent environmental concerns: high cooling loads and Urban Heat Islands. These two problems are linked and exhibit the potential micro and mesoscale benefits of reducing roof surface temperature. Cool roofs are part of a larger set of solutions to tackle these two issues and so must be considered in the context of the multitude of other mitigation measures. This report discusses the ways in which a cool roof affects a building envelope and Urban Heat Islands, and what this means in the context of Southern California and Pomona College. Due to the already energy efficient clay tile on most Pomona roofs, the gains from reflective coatings would be limited. However there are several flat roofs on campus that could benefit from the application of a reflective coating. These benefits would come in the form of cooling energy cost reduction to individual buildings. These benefits would not be so drastic as to necessitate immediately applying reflective coatings, but flat roofs should be updated with an energy efficient coating as part of regularly scheduled resurfacin

Discovery and Experts under the Federal Rules of Civil Procedureq

The problem of delineating the boundaries of discovery under Rules 26-37 of the Federal Rules of Civil Procedure is constant, for the language of limitation in the rules themselves remains vague. The discretionary nature of these rules suggests determination of each case on its own record. The burden so imposed on district judges and the lack of definite standards in the rules themselves governing the exercise of discretion have undoubtedly contributed to the adoption by many judges of rather inflexible ancillary rules for the application of discovery in questionable areas. One of these areas concerns the extent to which expert witnesses\u27 are subject to the discovery rules

Comprehensive Study of Study of Optimal Synergetic Skip Entries with Dynamic Thrust Vectoring Control

The atmospheric skip entry has been studied since London\u27s presentation in 1962 describing a more fuel efficient means of altering the orbital inclination of satellites. Since London, research over the decades since has traversed many aspects of this field with varying degrees of success. The present research employs the use of modern optimal control software, complex dynamics with minor simplifications, and thrust vectoring to re-approach the aerocruise atmospheric skip entry. Using the aerodynamics of the X-34, the aerocruise problem is first compared to the un-powered aeroglide where it is shown that the aerocruise is capable of increasing the inclination change by an average of 10°, and can be used more effectively when constraints on heating and deceleration rates are applied. A typical assumption of aerocruise maneuvers, that thrust be opposite of drag proved to not be the optimal solution. Optimal thrust angle solutions tend to guide the thrust vector in the direction of the atmospheric turn, and approximately 10° in the direction of lift. This research shows that thrust vectoring could be utilized in trans-atmospheric vehicle (TAV) design to increase the inclination change during an atmospheric maneuver. In addition, various vehicle parameter changes are studied and their results analyzed for the purpose of TAV design. Compared to the exo-atmospheric plane change the thrust vectoring aerocruise grants an additional 28.3° of inclination change; a ∆V savings equivalent to 3.67 km/s

Revealing the Warm-Hot Intergalactic Medium with OVI Absorption

Hydrodynamic simulations of growth of cosmic structure suggest that 30-50% of the total baryons at z=0 may be in a warm-hot intergalactic medium (WHIM) with temperatures ~10^5-10^7K. The O VI \lambda \lambda 1032, 1038 absorption line doublet in the FUV portion of QSO spectra provides an important probe of this gas. Utilizing recent hydrodynamic simulations, it is found that there should be ~5 O VI absorption lines per unit redshift with equivalent widths >= 35 mA, decreasing rapidly to ~0.5 per unit redshift at >= 350 mA. About 10% of the total baryonic matter or 20-30% of the WHIM is expected to be in the O VI absorption line systems with equivalent width >= 20 mA; the remaining WHIM gas may be too hot or have too low metallicity to be detected in O VI. We find that the simulation results agree well with observations with regard to the line abundance and total mass contained in these systems. Some of the O VI systems are collisionally ionized and some are photoionized, but most of the mass is in the collisionally ionized systems. We show that the gas that produces the O VI absorption lines does not reside in virialized regions such as galaxies, groups, or clusters of galaxies, but rather has an overdensity of 10-40 times the average density. These regions form a somewhat connected network of filaments. The typical metallicity of these regions is 0.1-0.3Zsun.Comment: accepted to ApJ Letters; full color Figure 1 may be obtained at http://astro.princeton.edu/~cen/PROJECTS/p2/p2.html (at the bottom of the page

Western Legacy

A selection of photos portraying Western Legacy

Cosmic Chemical Evolution

Numerical simulations of standard cosmological scenarios have now reached the degree of sophistication required to provide tentative answers to the fundamental question: Where and when were the heavy elements formed? Averaging globally, these simulations give a metallicity that increases from 1% of the solar value at $z=3$ to 20% at present. This conclusion is, in fact, misleading, as it masks the very strong dependency of metallicity on local density. At every epoch higher density regions have much higher metallicity than lower density regions. Moreover, the highest density regions quickly approach near solar metallicity and then saturate, while more typical regions slowly catch up. These results are much more consistent with observational data than the simpler picture (adopted by many) of gradual, quasi-uniform increase of metallicity with time.Comment: ApJ(Letters) in press, 15 latex pages and 4 figure