Digital Commons Network^™

High-Mobility Few-Layer Graphene Field Effect Transistors Fabricated On Epitaxial Ferroelectric Gate Oxides, X. Hong, A. Posadas, K. Zou, C. H. Ahn, J. Zhu

Xia Hong Publications

The carrier mobility μ of few-layer graphene (FLG) field-effect transistors increases tenfold when the SiO₂ substrate is replaced by single-crystal epitaxial Pb(Zr_0.2Ti_0:8)O₃ (PZT). In the electron-only regime of the FLG, μ reaches 7 X 10⁴ cm² / Vs at 300 K for n = 2.4 X 10¹²=cm², 70% of the intrinsic limit set by longitudinal acoustic (LA) phonons; it increases to 1.4 X 10⁵ cm² / Vs at low temperature. The temperature-dependent resistivity p(T) reveals a clear signature of LA phonon scattering, yielding …

Quantum Scattering Time And Its Implications On Scattering Sources In Graphene, X. Hong, K. Zou, J. Zhu

Xia Hong Publications

We determine the quantum scattering time T_q in six graphene samples with mobility of 4 400<μ <17 000 cm² /V s over a wide range of carrier density (1.2<n<6X10¹²/cm2). T_q derived from Shubnikov–de Haas oscillation ranges ~25–74 fs, corresponding to a single-particle level broadening of 4.5–13 meV. The ratio of the transport to quantum scattering time T_t /T_q spans 1.5–5.1 in these samples, which can be quantitatively understood combining scattering from short-ranged centers and charged impurities located within 2 nm of the graphene sheet. Our results suggest that charges residing on the SiO …

Accumulation Of A 5′ Proximal Subgenomic Rna Of Citrus Tristeza Virus Is Correlated With Encapsidation By The Minor Coat Protein, Siddarame Gowda, Satyanarayana Tatineni, Svetlana Y. Folimonova, Mark E. Hilf, William O. Dawson

Department of Plant Pathology: Faculty Publications

During replication, Citrus tristeza virus (CTV) produces large amounts of two unusual subgenomic (sg) RNAs that are positive-stranded and 5′ coterminal. Although these RNAs are produced in similar amounts and are similar in size, with LMT1 (~750 nt) only slightly larger than LMT2 (~650), we found that the similar sgRNAs are produced differently. We previously showed that the LMT1 RNA is produced by premature termination during genomic RNA synthesis. However, LMT2 production was found to correlate with virion assembly instead of RNA replication. The time course of accumulation of the LMT2 RNA occurred late, coinciding with virion accumulation. The long …

First-Principles Analysis Of Spin-Disorder Resistivity Of Fe And Ni, Aleksander L. Wysocki, Renat F. Sabirianov, Mark Van Schilfgaarde, Kirill D. Belashchenko

Department of Physics and Astronomy: Faculty Publications

Spin-disorder resistivity of Fe and Ni and its temperature dependence are analyzed using noncollinear density functional calculations within the supercell method. Different models of thermal spin disorder are considered, including the mean-field approximation and the nearest-neighbor Heisenberg model. If the local moments are kept frozen at their zero-temperature values, very good agreement with experiment is obtained for Fe but for Ni the resistivity at elevated temperatures is significantly overestimated. Agreement with experiment for Fe is improved if the local moments are made self-consistent. The effect of short-range order on spindisorder resistivity is more pronounced in Ni compared to Fe but …

Citric Acid Cross-Linking Of Starch Films, Narendra Reddy, Yiqi Yang

Department of Textiles, Merchandising and Fashion Design: Faculty Publications

This paper shows that citric acid can cross-link starch and improve the tensile strength, thermal stability and decrease the dissolution of starch films in water and formic acid. The poor mechanical properties and water stability of starch have restricted its industrial applications. Although cross-linking is a common approach to improve the properties of starch products, current starch cross-linking methods are either expensive, toxic or do not impart the desired properties to the cross-linked materials. In this research, the possibility of cross-linking starch films using citric acid to improve their strength and stability was examined. Citric acid cross-linked starch films show …

Relating Groundwater To Seasonal Wetlands In Southeastern Wisconsin, Usa, John D. Skalbeck, Donald M. Reed, Randall J. Hunt, Jamie D. Lambert

United States Geological Survey: Staff Publications

Historically, drier types of wetlands have been difficult to characterize and are not well researched. Nonetheless, they are considered to reflect the precipitation history with little, if any, regard for possible relation to groundwater. Two seasonal coastal wetland types (wet prairie, sedge meadow) were investigated during three growing seasons at three sites in the Lake Michigan Basin, Wisconsin, USA. The six seasonal wetlands were characterized using standard soil and vegetation techniques and groundwater measurements from the shallow and deep systems. They all met wetland hydrology criteria (e.g., water within 30 cm of land surface for 5% of the growing season) …

Missouri River Recovery Program: Reclaiming Lost Habitat: Real Estate Program

United States Army Corps of Engineers, Omaha District

Historically, the Missouri River continually reshaped itself by eroding banks in some areas and building up islands and sandbars in other areas. The river’s dynamic nature provided plenty of habitat for native species of animals and plants.

Efforts in the 1900s to manage the river by building dams, levees and a navigation channel provided many social and economic benefits to the nation but drastically reduced the amount of habitat available for the river’s native species. Today, lack of habitat is a major reason that several Missouri River species are endangered or threatened, such as the pallid sturgeon, least tern and …

Lower Yellowstone River Irrigation Dam, Fish Protection And Passage

United States Army Corps of Engineers, Omaha District

This Value Engineering (VE) Report summarizes the events of the VE workshop facilitated by GeoVal, Inc., June 1-5, 2009 for the U.S. Army Corps of Engineers (USACE) Omaha District, Nebraska. The Lower Yellowstone River Irrigation Dam, Fish Protection and Passage Value Engineering Study focuses on the assessment of alternatives for meeting Federal project objectives examining current plans and programs to seek out alternative approaches and ideas that will improve the overall performance of the project.

Federal project objectives of the Lower Yellowstone River Irrigation Dam, Fish Protection and Passage Project are to:

-Continue to provide reliable irrigation water delivery to …

Missouri River Recovery Program: Missouri River Basin

United States Army Corps of Engineers, Omaha District

The Missouri River, the nation’s longest, travels more than 2,300 miles from Three Forks, Montana, to join the Mississippi River near St. Louis, Missouri. For centuries, the river has served as the center of life for the inhabitants of North America’s Great Plains. Following exploration and mapping by Lewis and Clark’s Corps of Discovery in the early 1800s, the Missouri River became the gateway to the West.

Historically, the dynamic and untamed Missouri River has produced violent floods in the spring and summer with erosive forces that ate away its banks and turned its waters the color of mud.

Since …

Missouri River Recovery Program: Emergent Sandbar Habitat

United States Army Corps of Engineers, Omaha District

This Value Engineering (VE) Report summarizes the events of the April 6-8, 2009 VE workshop facilitated by GeoVal, Inc. for the U.S. Army Corps of Engineers (USACE) Omaha District, Nebraska. The Missouri River Recovery Program - Emergent Sandbar Habitat Value Engineering Study focuses on the assessment of the Missouri River Recovery Program (MRRP) Habitat Creation Project with specific focus on the creation of emergent sandbar habitats, examining current plans and programs to seek out alternative approaches and ideas that will improve the overall performance of the program.

The MRRP seeks to mitigate near-term losses of Missouri River habitats and recover …

Missouri River Recovery Program: Putting The Pieces Together: Mrrp Main Programs

United States Army Corps of Engineers, Omaha District

The Missouri River Recovery Program (MRRP) is a comprehensive effort led by the U.S. Army Corps of Engineers in partnership with the U.S. Fish and Wildlife Service, Tribes, states, other federal agencies and non-governmental organizations to develop and implement actions to create a healthy Missouri River.

The MRRP consists of:

-The Missouri River Bank Stabilization and Navigation Project (BSNP) Fish
and Wildlife Mitigation Project

- The Amended Biological Opinion and the Corps’ Record of Decision related
to the Master Water Control Manual for the Missouri River

- The 2007 Water Resources Development Act

Each of these guiding authorities set out …

The Dynamics Of Development: Challenges For Bayesian Rationality, Nils Straubinger, Edward T. Cokely, Jeffrey R. Stevens

Department of Psychology: Faculty Publications

Commentary on Oaksford & Chater, Precis of Bayesian Rationality

Oaksford & Chater draw a rather static picture of human reasoning by focusing on typical patterns of responses from adults. We propose a more dynamic perspective, which considers that reasoning systematically varies within individuals over the lifespan (Howe & Rabinowitz 1996; Markovits & Barrouillet 2002) and between individuals with different levels of knowledge and expertise (Ericsson et al. 2006).

The original articles, the full set of commentaries, and the authors' response are attached (below) as an "Additional file."

Dynamic Modeling And Control Of Doubly Fed Induction Generators Driven By Wind Turbines, Wei Qiao

Department of Electrical and Computer Engineering: Faculty Publications

Two different models are presented and developed in PSCAD/EMTDC to represent a variable-speed wind turbine equipped with a doubly fed induction generator (DFIG). One is the most detailed switching-level (SL) model. The other is a simplified fundamental-frequency (FF) model. The effect of different shaft system representations on the dynamic behavior of the wind turbine generator (WTG) system and the issue of damping low-frequency torsional oscillations are investigated. Dynamic and transient simulation studies are carried out to compare two models with different shaft system representations. Results show that the FF model is sufficient while the lumpedmass shaft model is insufficient to …

Real-Time Implementation Of A Statcom On A Wind Farm Equipped With Doubly Fed Induction Generators, Wei Qiao, Ganesh Kumar Venayagamoorthy, Ronald G. Harley

Department of Electrical and Computer Engineering: Faculty Publications

Voltage stability is a key issue to achieve the uninterrupted operation of wind farms equipped with doubly fed induction generators (DFIGs) during grid faults. This paper investigates the application of a static synchronous compensator (STATCOM) to assist with the uninterrupted operation of a wind turbine driving a DFIG, which is connected to a power network, during grid faults. The control schemes of the DFIG rotor- and grid-side converters and the STATCOM are suitably designed and coordinated. The system is implemented in real-time on a Real Time Digital Simulator. Results show that the STATCOM improves the transient voltage stability and therefore …

Enhanced Chemical Vapor Deposition Of Diamond By Wavelength-Matched Vibrational Excitations Of Ethylene Molecules Using Tunable Co2 Laser Irradiation, Hao Ling, Q. Xie, T. Gebre, X. K. Shen, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

Wavelength-matched vibrational excitations of ethylene (C₂H₄ molecules using a tunable carbon dioxide (CO₂) laser were employed to significantly enhance the chemical vapor deposition (CVD) of diamond in open air using a precursor gas mixture of C₂H₄, acetylene (C₂H₂), and oxygen (O₂). The CH₂-wag vibration mode (_v7) of the C₂H₄ molecules was selected to achieve the resonant excitation in the CVD process. Both laser wavelengths of 10.591 and 10.532 μm were applied to the CVD processes to compare …

The Magnetoelectric Effects In Multiferroic Composite Nanofibers, C. L. Zhang, W. Q. Chen, S. H. Xie, J. S. Yang, Jiangyu Li

Department of Engineering Mechanics: Faculty Publications

In this letter, we analyze the quasistatic and dynamic magnetoelectric responses of multiferroic composite nanofibers consisting of both ferroelectric and ferromagnetic phases and demonstrate that the nanofibers exhibit magnetoelectric responses orders of magnitude higher than multiferroic composite thin films of similar compositions. The analysis suggests that the multiferroic nanofibers are promising for magnetoelectric applications.

Harvesting Magnetic Energy Using Extensional Vibration Of Laminated Magnetoelectric Plates, C. L. Zhang, J. S Yang, W. Q. Chen

Department of Engineering Mechanics: Faculty Publications

Magnetically forced extensional vibrations of laminated plates with piezoelectric and piezomagnetic layers are analyzed theoretically. It is shown that such a structure can be used to harvest magnetic energy and convert it to electric energy. The output power and the energy conversion efficiency are calculated. The load dependence of the magnetoelectric coupling coefficient is also obtained.

Real-Time Depth Sectioning: Isolating The Effect Of Stress On Structure Development In Pressure-Driven Flow, Lucia Fernandez-Ballester, Derek W. Thurman, Julia A Kornfield

Department of Engineering Mechanics: Faculty Publications

Transient structure development at a specific distance from the channel wall in a pressure-driven flow is obtained from a set of real-time measurements that integrate contributions throughout the thickness of a rectangular channel. This “depth sectioning method” retains the advantages of pressure-driven flow while revealing flow-induced structures as a function of stress. The method is illustrated by applying it to isothermal shear-induced crystallization of an isotactic polypropylene using both synchrotron x-ray scattering and optical retardance. Real-time, depth-resolved information about the development of oriented precursors reveals features that cannot be extracted from ex-situ observation of the final morphology and that are …

Evaporation Induced Two-Dimensional Buckling Within Liquid Droplet, Ziguang Chen, Maozi Liu, Gang-Yu Liu, Li Tan

Department of Engineering Mechanics: Faculty Publications

Evaporation of a liquid droplet containing a thin layer of surfactants atop could generate two-dimensional buckling on surfaces. Herringbone features were produced via embedded nanoparticle beds. We assign transient surface tension as the driving force for such a phenomenon. Considering the surfactant layer as a thin elastic film, a continuum model is employed to calculate the mechanical properties of the layer. Particularly, we estimated an elastic modulus of 4 GPa for the surfactant layer, indicating rather strong mechanical properties of these small molecules when they are close packed to form supramolecules via noncovalent binding.

Achievable Rates And Resource Allocation Strategies For Imperfectly Known Fading Relay Channels, Junwei Zhang, M. Cenk Gursoy

Department of Electrical and Computer Engineering: Faculty Publications

Achievable rates and resource allocation strategies for imperfectly known fading relay channels are studied. It is assumed that communication starts with the network training phase in which the receivers estimate the fading coefficients. Achievable rate expressions for amplify-and-forward and decode-and-forward relaying schemes with different degrees of cooperation are obtained. We identify efficient strategies in three resource allocation problems: (1) power allocation between data and training symbols, (2) time/bandwidth allocation to the relay, and (3) power allocation between the source and relay in the presence of total power constraints. It is noted that unless the source-relay channel quality is high, cooperation …

Causes And Impacts Of Salinization In The Lower Pecos River, Christopher W. Hoagstrom

Great Plains Research: A Journal of Natural and Social Sciences (through 2013)

River salinization is a byproduct of water resource development that results from cumulative impacts of flow-regime modifications and crop irrigation. However, historical salinization in the Lower Pecos River is often attributed to natural, high-salinity groundwater. Here, evidence from literature and U.S. Geological Survey gaging stations is reviewed to summarize historical changes associated with water development that potentially contributed to Pecos River salinization. A suite of hydrological changes, initiated in the 1880s, likely contributed to streamflow salinization: (1) reduced flood frequency and magnitude, (2) diminished streamflow, (3) increased evapotranspiration, and (4) increased prevalence of natural, high-salinity groundwater. Salinization is presently highest …

Near-Surface Soil-Water Monitoring For Water Resources Management On A Wide-Area Basis In The Great Plains, K. G. Hubbard, J. You, V. Sridhar, E. Hunt, S. Korner, G. Roebke

Great Plains Research: A Journal of Natural and Social Sciences (through 2013)

In the Great Plains, soil water is one of the most critical factors related to sustainable production on cropland and rangeland, while the need for better water management grows in the face of increasing water demand during dry years. Soil water is also an important factor related to flood modeling and quantification of the boundary conditions in atmospheric models such as global circulation models. The objectives of this study were to install a wide-area automated soil-monitoring network, determine effective calibration procedures, and develop new products to illustrate the status of soil water. Soil-monitoring sensors were established at 51 sites across …

Sequencing, Analysis, And Annotation Of Expressed Sequence Tags For Camelus Dromedarius, Abdulaziz M. Al-Swailem, Maher M. Shehata, Faisel M. Abu-Duhier, Essam J. Al-Yamani, Khalid A. Al-Busadah, Mohammed S. Al-Arawi, Ali Y. Al-Khider, Abdullah N. Al-Muhaimeed, Fahad H. Al-Qahtani, Manee M. Manee, Badr M. Al-Shomrani, Saad M. Al-Qhtani, Amer S. Al-Harthi, Kadir C. Akdemir, Mehmet S. Inan, Hasan H. Otu

Department of Electrical and Computer Engineering: Faculty Publications

Despite its economical, cultural, and biological importance, there has not been a large scale sequencing project to date for Camelus dromedarius. With the goal of sequencing complete DNA of the organism, we first established and sequenced camel EST libraries, generating 70,272 reads. Following trimming, chimera check, repeat masking, cluster and assembly, we obtained 23,602 putative gene sequences, out of which over 4,500 potentially novel or fast evolving gene sequences do not carry any homology to other available genomes. Functional annotation of sequences with similarities in nucleotide and protein databases has been obtained using Gene Ontology classification. Comparison to available …

Genes Differentially Expressed By Cumulus Cells And Assays Using Same To Identify Pregnancy Competent Oocytes, Jose B. Cibelli, Amy E. Iager, Hasan H. Otu

Department of Electrical and Computer Engineering: Faculty Publications

A genetic means of identifying "pregnancy competent" oocytes is provided. The means comprises detecting the level of expression of one or more genes that are expressed at characteristic levels (upregulated or downregulated) in cumulus cells derived from pregnancy competent oocytes. This characteristic gene expression level, or pattern referred to herein as the "pregnancy signature", also can be used to identify subjects with underlying conditions that impair or prevent the development of a viable pregnancy, e.g., pre-menopausal condition, other hormonal dysfunction, ovarian dysfunction, ovarian cyst, cancer or other cell proliferation disorder, autoimmune disease and the like. In preferred embodiments the …

Preparing Advocates For Faculty Development: Expanding The Meaning Of “Growing Our Own”, Deborah S. Meizlish, Mary C. Wright

To Improve the Academy: A Journal of Educational Development

Discussions about preparing newcomers for faculty development focus almost exclusively on the staffing needs of teaching centers. Unfortunately, this emphasis significantly narrows what it means to prepare people for the field. Instead, we suggest that successful preparation has two elements: preparation of talented individuals for formal positions in the field and preparation of knowledgeable advocates or allies. As evidence, we present results from a survey of our center’s graduate teaching consultants, documenting how their work shaped their future connections to faculty development. Our results challenge centers to consider how their programming can “grow” both professionals in and advocates for faculty …

Meeting New Faculty At The Intersection: Personal And Professional Support Points The Way, Ann Riley

To Improve the Academy: A Journal of Educational Development

Faculty developers can play a significant role in increasing the retention of new faculty. This chapter presents a study conducted at a public research university that reveals that first-year faculty need personal, relational, and professional support. However, the importance of each type of support shifts during this first year, suggesting that faculty development efforts aimed toward new faculty should adjust accordingly. This study uses a sequential mixed-method design and is grounded in adult development theory, which views new faculty as adult learners in a career-life transition and faculty developers as adult educators.

Teaching Learning Processes—To Students And Teachers, Pamela E. Barnett, Linda C. Hodges

To Improve the Academy: A Journal of Educational Development

Our teaching and learning center serves faculty and graduate students as teachers and undergraduates as learners. Here we share the experiences of graduate student facilitators whom we trained to lead problem-solving skills workshops for undergraduates. Our aim was to help these graduate students see themselves as teachers of disciplinary thinking as much as of disciplinary content. However, they also began to reexamine their teaching beliefs and practices, recognize and respond to the needs of novice learners, and become more conscious of the demands of learning their disciplines. We offer this program as a model for developing future facuity.

Sample Investigating System, Martin M. Liphardt, Thomas E. Tiwald, Blaine D. Johs, Jeffery S. Hale, Craig M. Herzinger, Steven E. Green, Ping He, Ronald A. Synowicki, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

A spectroscopic system for adjusting spacing between an adjacent source/detector as a unit, and a sample, and a reflecting means for directing an incident beam which refelcts from said sample back onto said sample and then into the detector along a locus which is in a plance of incidence that is offset from that of the incident beam, or directly from the reflecting means into the detecor, including means for reducing reflections of a beam fo electromagnetic from the back of a sample, including methodology of use.

Simulation Of Coherent Radar Imaging Using Continuous Wave Noise Radar, Jing Xu, Michael Hoffman, B.L. Cheong, R.D. Palmer

Department of Electrical and Computer Engineering: Faculty Publications

A computationally simple cross-correlation model for multiple backscattering from a continuous wave (CW) noise radar is developed and verified with theoretical analysis and brute-force time-domain simulations. Based on this cross-correlation model, a modification of an existing numerical method originally developed by Holdsworth and Reid for spaced antenna (SA) pulsed radar is used to simulate the estimated cross correlation corresponding to atmospheric backscattering using a coherent CW noise radar. Subse- quently, coherent radar imaging (CRI) processing comparisons between the CW noise radar and a con- ventional pulsed radar are presented that verify the potential of CW noise radar for atmospheric imaging.

Review Of "Forty Acres And A Fool: How To Live In The Country And Still Keep Your Sanity." By Roger Welsch, Gwendolyn K. Meister

Great Plains Quarterly (through 2013)

These recent books by longtime Nebraska author, folklorist, and humorist Roger Welsch examine life in the Great Plains from two quite different perspectives. Forty Acres and a Fool, ostensibly a how-to book on moving to the country, is written in a personal, conversational style from the start. In the introduction Welsch relates the story of his own physical (and mental) relocation to Dannebrog, a village of 352 in central Nebraska. Although the book offers practical advice on everything from moving buildings to fitting in with the social life of one's chosen rural community, it feels essentially like sitting down …