Physical Sciences and Mathematics Commons^™

Synthesis And Characterization Of N- And P- Doped Tin Oxide Nanowires, Hoang Tran, Shankar B. Rananavare

Chemistry Faculty Publications and Presentations

Bulk-scale synthetic methods for preparing doped tin oxide (SnO₂) nanowires (NWs) are presented. n-and p-doping is achieved through insertion of Antimony and Lithium in tin oxide lattice, respectively. We also present a comparison of the structural and optical properties of SnO₂ nanoparticles (NPs), and SnO₂ NWs. Both n-type and p- type NWs display a characteristic red shift in their photoluminescence (PL) spectra. Surface plasmons observed in these systems imply high carrier concentrations. These corrosion resistant materials are useful in fabricating ultra-sensitive gas detectors and transparent electronics.

Positional Control Over Nanoparticle Deposition Into Nanoholes, Moshood K. Morakinyo, Shankar B. Rananavare

Chemistry Faculty Publications and Presentations

Controlled deposition of metal nanoparticles (NPs) into lithographic patterned nanoholes has been a major challenge. Electrostatic attraction was employed in directing gold NPs of precise size into e-beam lithographically patterned holes. Citrate stabilized gold NPs with a net negative surface charge were deposited on a positively charged well-bottom surface generated by adsorption of long-chain amino-terminated organosilane N-(2-aminoethyl)-11-aminoundecyltrimethoxy- silane (AATMS). Scanning electron microscopy (SEM) results indicate that deposition of NPs into patterned holes is a function of deposition time and NPs concentration. Other factors affecting NP fill fraction are thickness of silane and resist layer and spacing between the nanoholes.

Analysis Of The Conformational Behavior And Stability Of The Sap And Tsap Isomers Of Lanthanide(Iii) Nb-Dota-Type Chelates, Gyula Tircso, Benjamin Charles Webber, Benjamin E. Kucera, Victor G. Young, Mark Woods

Chemistry Faculty Publications and Presentations

Controlling the water exchange kinetics of macrocyclic Gd(3+) chelates, a key parameter in the design of improved magnetic resonance imaging (MRI) contrast media, may be facilitated by selecting the coordination geometry of the chelate. The water exchange kinetics of the mono- capped twisted square antiprism (TSAP) being much closer to optimal than those of the mono capped square antiprism (SAP) render the TSAP isomer more desirable for high relaxivity applications. Two systems have been developed that allow for selection of the TSAP coordination geometry in 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-type Gd(3+) chelates, both based upon the macrocycle nitrobenzyl cyclen. In this paper …

Bis Photobase Generator, Hoang Tran, Shankar B. Rananavare

Chemistry Faculty Publications and Presentations

The extension of 193nm technology is desirable due to the magnitude of past investments. Since “optical” advancements are increasingly difficult, there is a strong demand for more sophisticated “smart” resists to increase pattern density. Many studies have proven double pattering can be used for the extension of 193nm lithography. In this study, a new class of two stage photo base generators will be introduced along with the synthetic procedure and molecular characterization. The characterizations for exposure study by NMR have shown typical characteristics to stage decomposition under the exposure of 254nm light as well as promising pitch division. GCMS was …

Determination Of The Electric Field Intensity And Space Charge Density Versus Height Prior To Triggered Lightning, Christopher J. Biagi, Martin A. Uman, Jay Gopalakrishnan, J. D. Hill, Vladimir A. Rakov, T. Ngin, Douglas M. Jordan

Mathematics and Statistics Faculty Publications and Presentations

We infer the vertical profiles of space charge density and electric field intensity above ground by comparing modeling and measurements of the ground-level electric field changes caused by elevating grounded lightning-triggering wires. The ground-level electric fields at distances of 60 m and 350 m were measured during six wire launches that resulted in triggered lightning. The wires were launched when ground-level electric fields ranged from 3.2 to 7.6 kV m⁻¹ and the triggering heights ranged from 123 to 304 m. From wire launch time to lightning initiation time, the ground-level electric field reduction at 60 m ranged from 2.2 …

Interview With Adam Boesel, Green Micro Gym, 2011 (Audio), Adam Boesel

All Sustainability History Project Oral Histories

Interview of Adam Boesel by Teresa Celestine at Green Micro Gym Portland, Oregon on July 29th, 2011.

The interview index is available for download.

Hiv-1 Matrix Protein Binding To Rna, Ayna Alfadhli, Henry Mcnett, Seyram Tsagli, Hans Peter Bachinger, David H. Peyton

Chemistry Faculty Publications and Presentations

The matrix (MA) domain of the HIV-1 precursor Gag (PrGag) protein plays multiple roles in the viral replication cycle. One essential role is to target PrGag proteins to their lipid raft-associated phosphatidylinositol-(4,5)-bisphosphate (PI[4,5]P2) assembly sites at the plasma membranes (PMs) of infected cells. In addition to this role, several reports have implicated nucleic acid binding properties to retroviral MAs. Evidence indicates that RNA binding enhances the binding specificity of MA to PI(4,5)P2-containing membranes, and supports a hypothesis in which RNA binding to MA acts as a chaperone that protects MA from associating with inappropriate cellular membranes prior to PrGag delivery …

Carbon Sequestration In The New Jersey Pine Barrens Under Different Scenarios Of Fire Management, Robert M. Scheller, Steve Van Tuyl, Kenneth L. Clark, John Hom, Inga La Puma

Environmental Science and Management Faculty Publications and Presentations

The New Jersey Pine Barrens (NJPB) is the largest forested area along the northeastern coast of the United States. The NJPB are dominated by pine (Pinus spp.) and oak (Quercus spp.) stands that are fragmented and subject to frequent disturbance and forest management. Over long time periods (>50 years), the balance between oak and pine dominance is determined by fire frequency. As a consequence, the ability of the NJPB to sequester carbon may be contingent upon management activities as well as patterns of historic land use. We simulated 100 years of carbon change using three scenarios: (1) contemporary management …

Effectiveness Of Forest Management Strategies To Mitigate Effects Of Global Change In South-Central Siberia, Eric J. Gustafson, Anatoly Z. Shvidenko, Robert M. Scheller

Environmental Science and Management Faculty Publications and Presentations

We investigated questions about the ability of broad silvicultural strategies to achieve multiple objectives (reduce disturbance losses, maintain the abundance of preferred species, mitigate fragmentation and loss of age-class diversity, and sequester aboveground carbon) under future climate conditions in Siberia. We conducted a factorial experiment using the LANDIS-II landscape disturbance and succession model. Treatments included varying the size and amount of areas cut and the cutting method (selective or clearcut). Simultaneously, the model simulated natural disturbances (fire, wind, insect out-breaks) and forest succession under projected future climate conditions as predicted by an ensemble of global circulation models. The cutting method …

Lakeview, Oregon: The Little Town That Collaboration Saved, Laura Singer, Emily Rome, Liubov Doerr, Mari Saint Pierre, Dick Townsend, Alexander Freed, Daniel Mcduffee, Greg Nugent, Gretchen Olsen, Kirk Rea, Melissa Long, Ross D. Lamberth, Shelley D. Searle

National Policy Consensus Center Publications and Reports

The assessment team was made up of a diverse group - eight undergraduate PSU students, two graduate teaching assistants and one instructor - representing all ages, interests and fields of study. However, one thing everyone had in common was an interest in learning about collaboration and how it might be used to improve the state of Oregon, the nation and even the world. To that end, everyone participating in the Capstone course hoped to enhance their “Skills for Being an Effective Collaborator.” As this is the first time this course has been offered, we hope our success in meeting its …

Planning Approaches For Water Resources Development In The Lower Mekong Basin, Robert Costanza, Ida Kubiszewski, Peter Paquet, Jeffrey King, Shpresa Halimi, Hansa Sanguanngoi, Nguyen Luong Bach, Richard Frankel, Jiragorn Ganaseni, Apisom Intralawan, David Morell

Institute for Sustainable Solutions Publications and Presentations

Governments in the Lower Mekong Basin (LMB) face decisions that involve trade-offs between, for example, the economic benefits from hydropower generation and potentially irreversible negative impacts on the ecosystems that provide livelihoods and food security to the rural poor. These decisions involve complex problems that are both poorly understood in scientific terms and subject to rapid, potentially catastrophic change over time. A comprehensive, whole systems approach that adequately addresses the risks and uncertainties involved is necessary, but this is a daunting challenge for researchers, decision makers, and managers. They must develop the capacity to plan, coordinate, and implement a program …

Valuing Ecological Systems And Services, Robert Costanza, Ida Kubiszewski, David E. Ervin, Randall Bluffstone, Darrell Brown, Heejun Chang, Veronica Dujon, Elise F. Granek, Stephen Polasky, Vivek Shandas, J. Alan Yeakley, James Boyd

Institute for Sustainable Solutions Publications and Presentations

Making trade-offs between ecological services and other contributors to human well-being is a difficult but critical process that requires valuation. This allows both better recognition of the ecological, social, and economic trade-offs and also allows us to bill those who use up or destroy ecological services and reward those that produce or enhance them. It also aids improved ecosystems policy. In this paper we clarify some of the controversies in defining the contributions to human well-being from functioning ecosystems, many of which people are not even aware of.We go on to describe the applicability of the various valuation methods that …

Electronic Properties Of Metal-Arene Functionalized Graphene, Pavel Plachinda, David Evans, Raj Solanki

Physics Faculty Publications and Presentations

We have employed first-principles density-functional calculations to study the electronic characteristics of covalently functionalized graphene by metal-bis-arene chemistry. It is shown that functionalization with M-bis-arene (M = Ti, V, Cr, Mn, Fe) molecules leads to an opening in the bandgap of graphene (up to 0.81 eV for the Cr derivative), and as a result, transforms it from a semimetal to a semiconductor. The bandgap induced by attachment of a metal atom topped by a benzene ring is attributed to modification of π-conjugation and depends on the concentration of functionalizing molecules. This approach offers a means of tailoring the band structure …

Bridging The Marine–Terrestrial Disconnect To Improve Marine Coastal Zone Science And Management, Benjamin I. Ruttenberg, Elise F. Granek

Environmental Science and Management Faculty Publications and Presentations

Coastal zone ecosystems sit between larger terrestrial and marine environments and, therefore, are strongly affected by processes occurring in both systems. Marine coastal zone systems provide a range of benefits to humans, and yet many have been significantly degraded as a result of direct and indirect human impacts. Management efforts have been hampered by disconnects both between management and scientific research and across linked marine–terrestrial systems. Management jurisdictions often start or end at the shoreline, and multiple agencies at different levels of government often have overlapping or conflicting management goals or priorities, or suffer from a lack of knowledge or …

Investigations Into Whole Water, Prototropic And Amide Proton Exchange In Lanthanide(Iii) Dota-Tetraamide Chelates, Mark Woods, Azhar Pasha, Piyu Zhao, Gyula Tircso, Somdatta Chowdhury, Garry Kiefer, Donald E. Woessner, A. Dean Sherry

Chemistry Faculty Publications and Presentations

Lanthanide(III) chelates of DOTA-tetraamide ligands have been an area of particular interest since the discovery that water exchange kinetics are dramatically affected by the switch from acetate to amide side-chain donors. More recently these chelates have attracted interest as potential PARACEST agents for use in MRI. In this paper we report the results of studies using chemical exchange saturation transfer (CEST) and some more recently reported chelates to re-examine the exchange processes in this class of chelate. We find that the conclusions of Parker and Aime are, for the most part, solid; water exchange is slow and a substantial amount …

Interview With Ethan Beck, Ethan Beck Homes, 2011 (Audio), Ethan Beck

All Sustainability History Project Oral Histories

Interview of Ethan Beck by Sara Scott at Portland State University on June 2nd, 2011.

The interview index is available for download.

Landslide Susceptibility In Tryon State Park, Oregon, Tracy E. Handrich

Anthós

LIDAR and topographic data were used to identify areas of high landslide susceptibility. An arctangent equation was used to calculate slope angle, design criteria of susceptibility and designate zones of high, moderate, and low risk.

Leadership In Sustainable Chemicals Policy: Opportunities For Oregon, Jennifer H. Allen, Alexis Dinno

Institute for Sustainable Solutions Publications and Presentations

Oregon is uniquely positioned to lead in the development of safer alternatives to toxic chemicals. Existing chemicals policy in the United States does not comprehensively protect human health or the environment from the potential impacts of chemical exposure. Very few of the 84,000 chemical substances produced, processed or imported for commercial purposes in the United States have been studied for health and environmental impacts. The federal Environmental Protection Agency has access to only limited information about potential health or environmental hazards. Manufacturers have the right to withhold what they consider to be confidential business information. Because of this lack of …

Embedding Parallel Computation In A Stochastic Mesh Network: A Morphogenetic Approach, Max Orhai

Anthós

Many basic techniques in computer science have been founded on the assumption that physical computing resources are scarce but orderly, and that the cost of effective direct communication between physically distant parts of a computer system is affordable. In ubiquitous computing systems such as sensor networks, or in the design of nano-scale systems, these familiar assumptions may not hold.

What if we suppose instead that computing capacity is plentiful, but that only local communication is possible, and the exact structure of the communication network is not known in advance? This is the domain of spatial programming.

How can we program …

Mapping Conservation Opportunity Areas For The Intertwine's Regional Conservation Strategy, Theresa Burcsu, James S. Kagan

Institute for Natural Resources Publications

As part of efforts to develop the Regional Conservation Strategy (RCS) for the greater Portland-Vancouver region, Oregon State University’s Institute for Natural Resources (INR) was asked to use spatial modeling to identify conservation opportunity areas (COAs). To complete the project, INR analysts proposed a strategy that would map high value areas using a landscape approach that is focused on relatively high spatial resolution data sets available for the whole metropolitan region. The approach creates 2 main metrics: one focused on terrestrial organisms and the other focused on aquatic and riparian organisms. These are combined to create a map of highly …

Tension Directly Stabilizes Reconstituted Kinetochore-Microtubule Attachments, Bungo Akiyoshi, Krishna K. Sarangapani, Andrew F. Powers, Christian R. Nelson, Steve Reichow, Hugo Arellano-Santoyo, Tamir Gonen, Jeffrey A. Ranish, Charles L. Asbury, Sue Biggins

Chemistry Faculty Publications and Presentations

Kinetochores are macromolecular machines that couple chromosomes to dynamic microtubule tips during cell division, thereby generating force to segregate the chromosomes. Accurate segregation depends on selective stabilization of correct ‘bi-oriented’ kinetochore-microtubule attachments, which come under tension due to opposing forces exerted by microtubules. Tension is thought to stabilize these bi-oriented attachments indirectly, by suppressing the destabilizing activity of a kinase, Aurora B. However, a complete mechanistic understanding of the role of tension requires reconstitution of kinetochore-microtubule attachments for biochemical and biophysical analyses in vitro. Here we show that native kinetochore particles retaining the majority of kinetochore proteins can be …

Resizable, Scalable, Concurrent Hash Tables, Josh Triplett, Paul E. Mckenney, Jonathan Walpole

Computer Science Faculty Publications and Presentations

We present algorithms for shrinking and expanding a hash table while allowing concurrent, wait-free, linearly scalable lookups. These resize algorithms allow the hash table to maintain constant-time performance as the number of entries grows, and reclaim memory as the number of entries decreases, without delaying or disrupting readers.

We implemented our algorithms in the Linux kernel, to test their performance and scalability. Benchmarks show lookup scalability improved 125x over readerwriter locking, and 56% over the current state-of-the-art for Linux, with no performance degradation for lookups during a resize.

To achieve this performance, this hash table implementation uses a new concurrent …

Resizable, Scalable, Concurrent Hash Tables Via Relativistic Programming, Josh Triplett, Paul E. Mckenney, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Presentation focusing on software synchronization, thread locking, transactional memory, and relativistic programming. Hash table algorithms are presented with examples of relativistic list insertion and removal, and related data structures. Existing approaches are compared to new methodologies and future work with relativistic data structures.

Interview With Franklin Jones, B-Line, 2011 (Audio), Franklin Jones

All Sustainability History Project Oral Histories

Interview of Franklin Jones by Grant Russ at Portland, Oregon on May 31st, 2011.

The interview index is available for download.

Systems Ideas For The Scientific And Societal Imperatives Of The Coastal Ocean: Case Of The Bp Oil Gusher In The Gulf Of Mexico, Spring & Summer 2010, Christopher Mooers

Systems Science Friday Noon Seminar Series

In recent decades, great progress has been made in advancing the scientific understanding of the coastal ocean (i.e., the 200 nautical mile Exclusive Economic Zone (EEZ)) across a broad set of disciplines. Simultaneously, the societal use of the coastal ocean has skyrocketed through, for example, increased shipping & boating, sports & commercial fishing, and exploitation of non-living resources, such as, oil & gas extraction and sand & gravel mining. International law and national policy assign coastal nations the responsibility for stewardship (i.e., wise management) of their respective EEZs. The scope of the stewardship and applications can be summarized as (1) …

Spatial And Temporal Patterns In The Influence Of Land Use On Water Quality In Five Portland Area Creeks Representing Differing Levels Of Urbanization, Heejun Chang, Madeline Steele, Zoe Bonak

Geography Faculty Publications and Presentations

While the negative effects of urban development on freshwater systems are well documented, impacts of human disturbance on water quality vary depending on land cover, local climate, and temporal and spatial scales of analysis. To better understand this variation, we analyzed water quality data for a total of 15 sites from six Portland, Oregon area creeks at multiple spatial and temporal scales. The creeks are characterized by differing levels of urban development, from relatively pristine to highly developed. More than ten years of monthly data gathered by the Portland Bureau of Environmental Services were used to analyze temporal trends, and …

Effects Of Climate Change On Water Quality In The Yaquina Estuary, Oregon, Cheryl A. Brown, Darrin Sharp, Heejun Chang, Madeline Steele

Geography Faculty Publications and Presentations

As part of a larger study to examine the effect of climate change (CC) on estuarine resources, we simulated the effect of rising sea level, alterations in river discharge, and increasing atmospheric temperatures on water quality in the Yaquina Estuary. Due to uncertainty in the effects of climate change, initial model simulations were performed for different steady river discharge rates that span the historical range in inflow, and for a range of increases in sea level and atmospheric temperature. Model simulations suggest that in the central portion of the estuary (19 km from mouth), a 60-cm increase in sea level …

Assessment Of The Hydrologic Response To Climate Change In The Upper Deschutes River Basin, Central Oregon, Heejun Chang, M. Scott Waibel, Marshall W. Gannett, Christina L. Hulbe

Geography Faculty Publications and Presentations

Effects of climate change in the Cascade Range will likely include more rain, less snow, and earlier snowmelt in the Cascade Range as compared to present conditions. These changes, in turn, will affect the timing of runoff, groundwater recharge, and groundwater discharge to spring-fed streams. This hydrologic response needs to be examined and understood due to implications for water management. In this study, a water- and energy-balance model was used to explore 21st century changes in the water budget in the upper Deschutes Basin, and a groundwater model was used to evaluate the response of the groundwater system to those …

Climate Change And Shifts In Water Related Ecosystem Services In The Tualatin And Yamhill River Basins, Heejun Chang, Terrance Anthony, Driss Ennaanay, Manu Sharma

Geography Faculty Publications and Presentations

Water related ecosystem services (WES), such as flow regulation, drinking water supply, temperature regulation, and water recreational activities, are affected by anthropogenic climate change. Forecasting potential shifts in such WES is critical to identifying the form and magnitude of likely impacts. We quantified the levels and values of WES under multiple climate change scenarios in the two watersheds located in the Portland metropolitan area, Oregon, USA using the combination of a hydrologic model Better Assessment Science Integrating point and Non-point Sources - Soil and Water Assessment Tool (BASINS-SWAT) and an ecosystem evaluation model ? Integrated Valuation of Ecosystem Services and …

Climate Change Impact On Drought Risk And Uncertainty In The Willamette River Basin, Heejun Chang, Il-Won Jung

Geography Faculty Publications and Presentations

Climate change due to global warming could induce more frequent droughts in the Willamette River Basin because less snowfall in winter and earlier snowmelt due to temperature increase may lead to decreases in spring and summer streamflow. This study examines possible changes in drought risk using two drought indices, Standardized Precipitation Index (SPI) and Standardized Runoff Index (SRI). SPI represents a climatological drought index that considers only precipitation change, while SRI is a hydrological drought index that considers water balance change. In rainfall-dominated regions in the Willamette Valley, SPI is a useful drought index. In snow-dominated regions in the High …