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Articles 1 - 8 of 8

Full-Text Articles in Physical Sciences and Mathematics

An Analysis Of The Chemical Processes In The Smoke Plume From A Savanna Fire, Jorg Trentmann, Robert J. Yokelson, Peter V. Hobbs, Tanja Winterrath, Ted J. Christian, Meinrat O. Andreae, Sherri A. Mason Jun 2005

An Analysis Of The Chemical Processes In The Smoke Plume From A Savanna Fire, Jorg Trentmann, Robert J. Yokelson, Peter V. Hobbs, Tanja Winterrath, Ted J. Christian, Meinrat O. Andreae, Sherri A. Mason

Chemistry and Biochemistry Faculty Publications

[1] Photochemistry in young plumes from vegetation fires significantly transforms the initial fire emissions within the first hour after the emissions are injected into the atmosphere. Here we present an investigation of field measurements obtained in a smoke plume from a prescribed savanna fire during the SAFARI 2000 field experiment using a detailed photochemical box-dilution model. The dilution used in the model simulations was constrained by measurements of chemically passive tracers (e.g., CO) near and downwind of the fire. The emissions of the dominant carbonaceous compounds, including oxygenated ones, were taken into account. The field measurements revealed significant production of …


Preparation, Structural Characterization, And Dynamic Properties Investigation Of Permalloy Antidot Arrays, Andriy Vovk, Leszek M. Malkinski, Scott L. Whittenburg, Charles O'Connor, Jin-Seung Jung, Suk-Hong Min May 2005

Preparation, Structural Characterization, And Dynamic Properties Investigation Of Permalloy Antidot Arrays, Andriy Vovk, Leszek M. Malkinski, Scott L. Whittenburg, Charles O'Connor, Jin-Seung Jung, Suk-Hong Min

Chemistry and Biochemistry Faculty Publications

Regular nanosized structures are considered to be promising materials for magnetic information storage media with high density of information. Recently attention was paid to static and dynamic magnetic properties arising from dimensional confinement in such nanostructures. Here we present an investigation of permalloy antidot arrays of different thicknesses. Thin permalloyfilms of thickness ranging from were deposited on nanoporous membranes with a pore size of . It was found that additional ferromagnetic resonance peaks appear for film thicknesses below , while films with larger thicknesses show resonanceproperties similar to continuous films. A comparison between the filmsdeposited onto Si wafers and porous …


Wave Field Migration As A Tool For Estimating Spatially Continuous Radar Velocity And Water Content In Glaciers, John H. Bradford, Joel T. Harper Apr 2005

Wave Field Migration As A Tool For Estimating Spatially Continuous Radar Velocity And Water Content In Glaciers, John H. Bradford, Joel T. Harper

Geosciences Faculty Publications

Normal-moveout velocity analysis can lead to significant overestimates of the velocity structure of temperate glaciers since most englacial reflectors approximate point scatters and violate the assumption of planar flat lying reflectors. Migration velocity analysis (MVA) is a tool that does not depend on the assumption of flat lying reflectors. MVA can provide laterally and vertically continuous velocity estimates from conventional common-offset radar sections. In a study of temperate Bench Glacier, Alaska, we used MVA coupled with dielectric modeling to estimate the distribution of water content along a cross-section of the glacier. We found the glacier has two layers, an upper …


Assessing The Accuracy Of Respondents Reports Of The Location Of Their Home Relative To A National Forest Boundary And Forest Cover, John D. Baldridge, James T. Sylveste, William T. Borrie Jan 2005

Assessing The Accuracy Of Respondents Reports Of The Location Of Their Home Relative To A National Forest Boundary And Forest Cover, John D. Baldridge, James T. Sylveste, William T. Borrie

Society and Conservation Faculty Publications

This paper assesses the accuracy of responses to a question that asks the location of respondents’ homes relative to a National Forest boundary. The analysis also assesses the accuracy of respondent reports on forest cover in the area surrounding their home. We find non-ignorable error in the responses to both questions. The remainder of this paper is divided into three sections. First, the methods used for this study are described as are limitations of the study. Second, we illustrate the study’s results. Finally, we discuss our results and conclusions.


State Aggregation And Population Dynamics In Linear Systems, Jonathan E. Rowe, Michael D. Vose, Alden H. Wright Jan 2005

State Aggregation And Population Dynamics In Linear Systems, Jonathan E. Rowe, Michael D. Vose, Alden H. Wright

Computer Science Faculty Publications

We consider complex systems that are composed of many interacting elements, evolving under some dynamics. We are interested in characterizing the ways in which these elements may be grouped into higher-level, macroscopic states in a way that is compatible with those dynamics. Such groupings may then be thought of as naturally emergent properties of the system. We formalize this idea and, in the case that the dynamics are linear, prove necessary and sufficient conditions for this to happen. In cases where there is an underlying symmetry among the components of the system, group theory may be used to provide a …


Diurnal Water-Pressure Fluctuations: Timing And Pattern Of Termination Below Bench Glacier, Alaska, Usa, T. J. Fudge, Joel T. Harper, Neil Humphrey, W. Tad Pfeffer Jan 2005

Diurnal Water-Pressure Fluctuations: Timing And Pattern Of Termination Below Bench Glacier, Alaska, Usa, T. J. Fudge, Joel T. Harper, Neil Humphrey, W. Tad Pfeffer

Geosciences Faculty Publications

Observations from basal water-pressure sensors along the length of Bench Glacier, Alaska, USA, show that diurnal fluctuations of water pressure are seasonal and restricted to summer. Most notable about these fluctuations is their disappearance in the late summer and early autumn, long before the seasonal end of diurnal meltwater input. Here we present data documenting the end of diurnal water-pressure fluctuations during the 2002 and 2003 melt seasons. The end of diurnal fluctuations occurred abruptly in multiple boreholes spaced meters to kilometers apart. There was no obvious spatial progression of termination events, and a clear correlation with meteorological forcing or …


Evolution Of Subglacial Water Pressure Along A Glacier’S Length, Joel T. Harper, Neil Humphrey, W. Tad Pfeffer, T. J. Fudge, Shad O'Neel Jan 2005

Evolution Of Subglacial Water Pressure Along A Glacier’S Length, Joel T. Harper, Neil Humphrey, W. Tad Pfeffer, T. J. Fudge, Shad O'Neel

Geosciences Faculty Publications

Observations from along the length of Bench Glacier, Alaska, USA, show that the subglacial water-pressure field undergoes a multiphase transition from a winter mode to a summer mode. Data were collected at the glacier surface, the outlet stream, and in a network of 47 boreholes spanning the length of the 7 km long glacier. The winter pressure field was near overburden, with low-magnitude (centimeter to meter scale) and long-period (days to weeks) variations. During a spring speed-up event, boreholes showed synchronous variations and a slight pressure drop from prior winter values. Diurnal pressure variations followed the speed-up, with their onset …


Historical Context And Hazardous Waste Facility Siting: Understanding Temporal Patterns In Michigan, Robin Saha, Paul Mohai Jan 2005

Historical Context And Hazardous Waste Facility Siting: Understanding Temporal Patterns In Michigan, Robin Saha, Paul Mohai

Environmental Studies Faculty Publications

This article tests the proposition that, beginning in the 1970s, historic growth of public environmental concern and opposition to waste facilities, as well as changes in the policy environment increasingly encouraged hazardous waste facilities siting to follow the path of least (political) resistance and resulted in environmental inequities. Our longitudinal analysis of sitings in the State of Michigan from 1950 to 1990 reveals a distinct temporal pattern supporting our hypotheses. Whereas significant racial, socioeconomic, and housing disparities at the time of siting were not in evidence for facilities sited prior to 1970, patterns of disparate siting were found for facilities …