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Mapping A Post-Shelby County Contingency Strategy, Luis Fuentes-Rohwer, Guy-Uriel E. Charles

Articles by Maurer Faculty

Professors Guy-Uriel E. Charles and Luis Fuentes-Rohwer argue that voting rights activists ought to be prepared for a future in which section 5 is not part of the landscape. If the Court strikes down section 5, an emerging ecosystem of private entities and organized interest groups of various stripes—what they call institutional intermediaries—may be willing and able to mimic the elements that made section 5 an effective regulatory device. As voting rights activists plot a post-Shelby County contingency strategy, they should both account for institutional intermediaries and think about the types of changes that could enhance the ability of these …

Exafs And Epr Analysis Of The Local Structure Of Mn-Doped Li2B4O7, T D. Kelly, L Kong, D A. Buchanan, A T. Brant, J. C. Petrosky, J W. Mcclory, V T. Adamiv, Y V. Burak, Peter A. Dowben

Peter Dowben Publications

The local structure of Mn-doped Li₂B₄O₇(001) was investigated using extended X-ray absorption fine structure (EXAFS) at the Mn K edge and electron paramagnetic resonance (EPR). The location of the Mn dopant in a lithium tetraborate crystal is consistent with occupation of a site with strong oxygen coordination. The Mn–O bond lengths are similar to those observed with Mn doping of the icosahedral based boron carbide whereMnis in a substitutional dopant in one of the cage sites. From EXAFS, the manganese does not appear to greatly alter the overall tetragonal form of lithium tetraborate, with …

Gamma And X-Ray Sensitivity Of Gd2O3 Heterojunctions, Juan A. Colon Santana, C M. Young, J W. Mcclory, J C. Petrosky, X Wang, P Liu, Jinke Tang, V T. Adamiv, Ya V. Burak, Keisuke Fukutani, Peter A. Dowben

Peter Dowben Publications

We find that Gd₂O₃ thin films strongly favor a (-402) texture growth on a variety of substrates and will form heterojunction diodes with silicon, especially when doped with oxygen vacancies. Even in the thin film limit, these heterojunction diodes appear to be sensitive to gamma radiation, likely from the X-rays created by scattering events, adding to the numerous hurdles that must be overcome if Gd based semiconductor devices are to be used for solid state neutron detection applications.

Adsorption Of Tcnqh-Functionalized Quinonoid Zwitterions On Gold And Graphene: Evidence For Dominant Intermolecular Interactions+, Lingmei Kong, Lucie Routaboul, Pierre Braunstein, Hong-Gi Park, Jaewu Choi, John P. Colon Cordova, E Vega, Luis G. Rosa, Bernard Doudin, Peter A. Dowben

Peter Dowben Publications

We experimentally investigate the electronic structure of the strongly dipolar, quinonoid-type molecule obtained by TCNQH-functionalization (TCNQH = (NC)₂CC₆H₄CH(CN)₂) of (6Z)-4-(butylamino)-6-(butyliminio)- 3-oxocyclohexa-1,4-dien-1-olate C₆H₂(...NHR)₂(...O)₂ (where R = n-C₄H₉) to be very similar after deposition from solution on either graphene or gold substrates. These zwitterion adsorbate thin films form structures that are distinct from those formed by related quinonoid molecules previously studied. We argue that adsorbate–adsorbate interactions dominate and lead to a Stranski–Krastanov ‘island growth’ mechanism.

Combinatorial Neural Codes From A Mathematical Coding Theory Perspective, Carina Curto, Vladimir Itskov, Katherine Morrison, Zachary Roth, Judy L. Walker

Department of Mathematics: Faculty Publications

Shannon’s seminal 1948 work gave rise to two distinct areas of research: information theory and mathematical coding theory. While information theory has had a strong influence on theoretical neuroscience, ideas from mathematical coding theory have received considerably less attention. Here we take a new look at combinatorial neural codes from a mathematical coding theory perspective, examining the error correction capabilities of familiar receptive field codes (RF codes).We find, perhaps surprisingly, that the high levels of redundancy present in these codes do not support accurate error correction, although the error-correcting performance of receptive field codes catches up to that of random …

Reviews Of Science For Science Librarians: Drought In The Agricultural And Geosciences Literature, Leslie M. Delserone, Adonna Fleming

University of Nebraska-Lincoln Libraries: Faculty Publications

Drought is a hot topic, given the climatic events of summer 2012 in the United States. This article provides a fundamental understanding of drought—its definitions, classifications, ratings, and impact on agriculture. Also included are introductions to drought-related research areas in the geosciences—specifically geology, hydrology, and atmospheric sciences—as well as pointers to reliable sources of information about drought from the agricultural and geosciences literature.

Making An Impact: Campus-Wide Collaboration For Course And Learning Space Transformation, Clarence Maybee, Tomalee Doan, Catherine Fraser Riehle

University of Nebraska-Lincoln Libraries: Faculty Publications

Most of us would agree that the roles of librarians have been changing with an almost mind-reeling rapidity. While this can be challenging, it also can provide excellent opportunities to support our students in their academic endeavors in new and meaningful ways. At Purdue University such an opportunity arrived in the shape of a provost-initiated, campus-wide course redesign program called Instruction Matters: Purdue Academic Course Transformation (IMPACT). This initiative aims to bring active-learning to foundational courses traditionally taught through lectures. Involved since the onset, Purdue librarians recognized the IMPACT initiative as one way to enter the conversations blooming on our …

Reclaiming “Anthropology: The Forgotten Behavioral Science In Management History” – Commentaries, Fred Luthans, Ivana Milosevic, Beth A. Bechky, Edgar H. Schein, Susan Wright, Davydd J. Greenwood

Department of Management: Faculty Publications

Purpose – This collection of commentaries on the reprinted 1987 article by Nancy C. Morey and Fred Luthans, “Anthropology: the forgotten behavioral science in management history”, aims to reflect on the treatment of the history of anthropological work in organizational studies presented in the original article.

Design/methodology/approach – The essays are invited and peer-reviewed contributions from scholars in organizational studies and anthropology.

Findings – The scholars invited to comment on the original article have seen its value, and their contributions ground its content in contemporary issues and debates.

Originality/value – The original article was deemed “original” for its time (1987), …

Jurassic Earthquake Sequence Recorded By Multiple Generations Of Sand Blows, Zion National Park, Utah, David Loope, James F. Elder, Vitaly A. Zlotnik, Richard M. Kettler, Darryll T. Pederson

Department of Earth and Atmospheric Sciences: Faculty Publications

Earthquakes along convergent plate boundaries commonly occur in sequences that are complete within 1 yr, and may include 8–10 events strong enough to generate sand blows. Dune crossbeds within the Jurassic Navajo Sandstone of Utah (western United States) enclose intact and truncated sand blows, and the intrusive structures that fed them. We mapped the distribution of more than 800 soft-sediment dikes and pipes at two small sites. All water-escape structures intersect a single paleo-surface, and are limited to the upper portion of the underlying set of cross-strata and the lower portion of the overlying set. A small portion of one …

Fostering Climate Change Education In The Central Great Plains: A Public Engagement Approach, Lisa M. Pytlikzillig, Timothy Steffensmeier, Amber Campbell Hibbs, Ben Champion, Eric Hunt, John A. Harrington, Jr., Jacqueline D. Spears, Natalie Umphlett, Tarik Abdel-Monem, Roger Bruning, Daniel Kahl

Lisa PytlikZillig Publications

Despite its increasing importance for sustainability, building widespread competency in the basic principles of climate literacy among the United States general public is a great challenge. This article describes the methods and results of a public engagement approach to planning climate change education in the Central Great Plains of the United States. Our approach incorporated contextual and lay expertise approaches to public engagement with a focus on supporting the self-determination of the specific stakeholder groups–rural producers, educators, and community members. An integration of results from the focus groups reveal that our approach was received positively and elicited a number of …

Review Of Electrochemical And Electrodischarge Machining, Kamlakar P. Rajurkar, M. M. Sundaram, A. P. Malshe

Department of Mechanical and Materials Engineering: Faculty Publications

Electrochemical and electro-discharge machining processes are the two major electro-machining processes with unique capabilities. Electrical Discharge Machining (EDM) and Electrochemical Machining (ECM) offer a better alternative or sometimes the only alternative in generating accurate 3-D complex shaped macro, micro and nano features and components of difficult–to-machine materials. Technological advances reported in electrochemical and electro discharge machining processes, which reflect the state of the art in academic and industrial research and applications, are briefly reviewed in this paper.

Wire Electro-Discharge Machining Of Titanium Alloy, Farnaz Nourbakhsh, Kamlakar P. Rajurkar, Ajay P. Malshe, Jian Cao

Department of Mechanical and Materials Engineering: Faculty Publications

This paper presents an experimental investigation of wire electro-discharge machining (WEDM) of titanium alloy. The objective is to investigate the effect of seven process parameters including pulse width, servo reference voltage, pulse current, and wire tension on process performance parameters (such as cutting speed, wire rupture and surface integrity). A Taguchi L18 design of experiment (DOE) has been applied. All experiments have been conducted using Charmilles WEDM. It was also found that the cutting speed increases with peak current and pulse interval. Surface roughness was found to increase with pulse width and decrease with pulse interval. The Analysis of Variance …

Selective Detection And Automated Counting Of Fluorescently-Labeled Chrysotile Asbestos Using A Dual-Mode High-Throughput Microscopy (Dm-Htm) Method, Myoung-Ock Cho, Hyo Mi Chang, Donghee Lee, Yeon Gyu Yu, Hwataik Han, Jung Kyung Kim

Department of Mechanical and Materials Engineering: Faculty Publications

Phase contrast microscopy (PCM) is a widely used analytical method for airborne asbestos, but it is unable to distinguish asbestos from non-asbestos fibers and requires time-consuming and laborious manual counting of fibers. Previously, we developed a high-throughput microscopy (HTM) method that could greatly reduce human intervention and analysis time through automated image acquisition and counting of fibers. In this study, we designed a dual-mode HTM (DM-HTM) device for the combined reflection and fluorescence imaging of asbestos, and automated a series of built-in image processing commands of ImageJ software to test its capabilities. We used DksA, a chrysotile-adhesive protein, for selective …

Photovoltaic Device, Jinsong Huang, Bin Yang, Yongbo Yuan

Department of Mechanical and Materials Engineering: Faculty Publications

An apparatus includes a substrate; and a photoactive layer disposed on the substrate. The photoactive layer includes an electron acceptor material; an electron donor material; and a material having dipoles.

Prediction Of The Thermomechanical Behavior Of Particle-Reinforced Metal Matrix Composites, Yi Hua, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

The objective of this paper was to predict the thermomechanical behavior of 2080 aluminum alloy reinforced with SiC particles using the Mori–Tanaka theory combined with the finite element method. The influences of particle volume fraction, stiffness, aspect ratio and orientation were examined in terms of effective Young’s modulus, Poisson’s ratio and coefficient of thermal expansion (CTE) of the composite. The microstructure induced local stress and strain field was obtained through the numerical models of the representative volume element. Results suggested that particle volume fraction had significant impact on the effective Young’s modulus, Poisson’s ratio and CTE of the composite. Stiffer …

Elastic–Plastic Analysis And Strength Evaluation Of Adhesive Joints In Wind Turbine Blades, Yi Hua, Ananth Ram Mahanth Kasavajhala, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

The objective of this paper is to investigate the performance of adhesive joints of carbon/epoxy wind turbine blade subjected to combined bending and tension loadings through finite element method. The influence of adhesive material properties and geometrical details including fillet and imperfections was examined in terms of interlaminar stresses in the adhesive layer. The variation of stress intensity with change in adhesive shear modulus has also been investigated, while contour integral method was used for evaluating the stress intensity factors (SIF) at the imperfection tip. Furthermore, the strength of the joint was assessed through the crack initiation and propagation analysis. …

Impact Damage On A Thin Glass Plate With A Thin Polycarbonate Backing, Wenke Hu, Yenan Wang, Jian Yu, Chian-Fong Yen, Florin Bobaru Ph.D.

Department of Mechanical and Materials Engineering: Faculty Publications

We present experimental and computational results for the impact of a spherical projectile on a thin glass plate with a thin polycarbonate backing plate, restrained in a metal frame, or in the absence of the frame. We analyze the dependence of the damage patterns in the glass plate on the increasing impact velocities, from 61 m/s to 200 m/s. Experimental results are compared with those from peridynamic simulations of a simplified model. The main fracture patterns observed experimentally are captured by the peridynamic model for each of the three projectile velocities tested. More accurate implementation of the actual boundary conditions …

Scalar Differential Equation For Slowly-Varying Thickness-Shear Modes In At-Cut Quartz Resonators With Surface Impedance For Acoustic Wave Sensor Application, Huijing He, Jiashi Yang, John A. Kosinski

Department of Mechanical and Materials Engineering: Faculty Publications

For time-harmonic motions, we generalize a 2-D scalar differential equation derived previously by Tiersten for slowly-varying thickness-shear vibrations of AT-cut quartz resonators. The purpose of the generalization is to include the effects of surface acoustic impedance from, e.g., mass layers or fluids for sensor applications. In addition to the variation of fields along the plate thickness, which is considered in the usual 1-D acoustic wave sensor models, the equation obtained also describes in-plane variations of the fields, and therefore can be used to study the vibrations of finite plate sensors with edge effects. The equation is compared with the theory …

Solution-Processed Nanoparticle Super-Float-Gated Organic Field-Effect Transistor As Un-Cooled Ultraviolet And Infrared Photon Counter, Yongbo Yuan, Qingfeng Dong, Bin Yang, Fawen Guo, Qi Zhang, Ming Han, Jinsong Huang

Department of Mechanical and Materials Engineering: Faculty Publications

High sensitivity photodetectors in ultraviolet (UV) and infrared (IR) range have broad civilian and military applications. Here we report on an un-cooled solution-processed UV-IR photon counter based on modified organic field-effect transistors. This type of UV detectors have light absorbing zinc oxide nanoparticles (NPs) sandwiched between two gate dielectric layers as a floating gate. The photon-generated charges on the floating gate cause high resistance regions in the transistor channel and tune the source-drain output current. This ‘‘super-float-gating’’ mechanism enables very high sensitivity photodetectors with a minimum detectable ultraviolet light intensity of 2.6 photons/µm²s at room temperature as well …

Analysis Of Electrically-Forced Vibrations Of Piezoelectric Mesa Resonators, Huijing He, Guo-Quan Nie, Jin-Xi Liu, Jiashi Yang

Department of Mechanical and Materials Engineering: Faculty Publications

We study the electrically forced thickness-shear and thickness-twist vibrations of stepped thickness piezoelectric plate mesa resonators made of polarized ceramics or 6-mm class crystals. A theoretical analysis based on the theory of piezoelectricity is performed, and an analytical solution is obtained using the trigonometric series. The electrical admittance, resonant frequencies, and mode shapes are calculated, and strong energy trapping of the modes is observed. Their dependence on the geometric parameters of the resonator is also examined.

Exploring The Design Space Of Multichannel Peer-To-Peer Live Video Streaming Systems, Miao Wang, Lisong Xu, Byrav Ramamurthy

School of Computing: Faculty Publications

Most of the commercial peer-to-peer (P2P) video streaming deployments support hundreds of channels and are referred to as multichannel systems. Recent research studies have proposed specific protocols to improve the streaming quality for all channels by enabling cross-channel cooperation among multiple channels. In this paper, we focus on the following fundamental problems in designing cooperating multichannel systems: 1) what are the general characteristics of existing and potential designs? and 2) under what circumstances should a particular design be used to achieve the desired streaming quality with the lowest implementation complexity? To answer the first question, we propose simple models based …

Non-Stationary Phenomenon In Large Team Information Sharing, Adam Eck, Leen-Kiat Soh

School of Computing: Technical Reports

Information sharing is important in agent-based sensing, especially for large teams where only a small subset of the agents can directly observe the environment. We consider the impact of non-stationarity in the observed phenomenon on the collective beliefs of such large teams. Non-stationarity is challenging because not only must the team converge to consistent, accurate beliefs (as studied previously), but, most importantly, the team must also frequently revise its beliefs over time as the phenomenon changes values. We analytically and empirically demonstrate the difficulty in revising beliefs over time with the standard model and pro-pose two novel solutions for improving …

Field Study Identifying Barriers And Delays In Data-To-Decision With Small Unmanned Aerial Systems, Brittany A. Duncan, Robin R. Murphy

School of Computing: Conference and Workshop Papers

This paper reports on lessons learned in rapidly getting data from a small tactical unmanned aerial system (sUAS) to an incident commander during a 2012 high fidelity hazardous materials exercise. In order to capture the Public Safety data-todecision path, observational data was collected on three flights of an AirRobot 100B sUAS, used extensively by the US Army, with HazMat specialists as part of a chemical train derailment exercise at the 2012 Summer Institute at Disaster City_R . The Summer Institute found that (i) the data path requires an average of 4 steps to go from the field to the …

Exploiting Soil Moisture Information For Adaptive Error Control In Wireless Underground Sensor Networks, Xin Dong, Mehmet C. Vuran

School of Computing: Conference and Workshop Papers

Wireless underground sensor networks (WUSNs) have recently been investigated for a wide range of applications. One challenge in wireless underground communications is its high bit error rate, especially at long distances. In WUSNs, the communication quality is substantially affected by the environment, especially the soil moisture. Thus, the underground channel quality can be effectively estimated based on local soil moisture readings. By utilizing the local soil moisture values to estimate the channel quality, adaptive error control mechanisms can be implemented for underground nodes. In this paper, two error control mechanisms, adaptive-rate forward error control and adaptive transmit power control, are …

Impacts Of Soil Moisture On Cognitive Radio Underground Networks, Xin Dong, Mehmet C. Vuran

School of Computing: Conference and Workshop Papers

Wireless underground communications is mainly characterized by the effects of soil moisture on antenna return loss and bandwidth as well as path loss. In this paper, the impacts of soil moisture, especially on underground channel capacity, are analyzed for underground wireless communications. It is shown that for a given antenna and soil moisture level, there exits an optimal operation frequency that maximizes channel capacity. While existing research on wireless underground communication is focused on fixed-frequency systems, this paper motivates the use of cognitive radio systems, which can adjust operation frequency in a wide range, for efficiency for wireless underground communication. …

An Empirical Comparison Of The Fault-Detection Capabilities Of Internal Oracles, Tingting Yu, Witawas Srisaan, Gregg Rothermel

School of Computing: Conference and Workshop Papers

Modern computer systems are prone to various classes of runtime faults due to their reliance on features such as concurrency and peripheral devices such as sensors. Testing remains a common method for uncovering faults in these systems, but many runtime faults are difficult to detect using typical testing oracles that monitor only program output. In this work we empirically investigate the use of internal test oracles: oracles that detect faults by monitoring aspects of internal program and system states. We compare these internal oracles to each other and to output-based oracles for relative effectiveness and examine tradeoffs between oracles involving …

Associations Of Students' Creativity, Motivation, And Self-Regulation With Learning And Achievement In College Computer Science Courses, Duane F. Shell, Melissa Patterson Hazley, Leen-Kiat Soh, Elizabeth Ingraham, Stephen Ramsay

School of Computing: Conference and Workshop Papers

The need for more post-secondary students to major and graduate in STEM fields is widely recognized. Students’ motivation and strategic self-regulation have been identified as playing crucial roles in their success in STEM classes. But, how students’ strategy use, self-regulation, knowledge building, and engagement impact different learning outcomes is not well understood. Our goal in this study was to investigate how motivation, strategic self-regulation, and creative competency were associated with course achievement and long-term learning of computational thinking knowledge and skills in introductory computer science courses. Student grades and long-term retention were positively associated with self-regulated strategy use and knowledge …

Segmenting Tables Via Indexing Of Value Cells By Table Headers, Sharad C. Seth, George Nagy

School of Computing: Conference and Workshop Papers

Correct segmentation of a web table into its component regions is the essential first step to understanding tabular data. Our algorithmic solution to the segmentation problem relies on the property that strings defining row and column header paths uniquely index each data cell in the table. We segment the table using only “logical layout analysis” without resorting to any appearance features or natural language understanding. We start with a CSV table that preserves the 2- dimensional structure and contents of the original source table (e.g., an HTML table) but not font size, font weight, and color. The indexing property of …

Directed Test Suite Augmentation, Zhihong Xu

School of Computing: Dissertations, Theses, and Student Research

Test suite augmentation techniques are used in regression testing to identify code elements affected by changes and to generate test cases to cover those elements. Whereas methods and techniques to find affected elements have been extensively researched in regression testing, the problem of generating new test cases to cover these elements cost-effectively has rarely been studied. We believe that reusing existing test cases will help us achieve this task. This research develops test suite augmentation techniques that reuse existing test cases to automatically generate new test cases to cost-effectively cover affected elements. We begin by using two dynamic test case …

Theory Guided Professional Development In Early Childhood Science Education, Soo-Young Hong, Julia C. Torquati, Victoria J. Molfese

Nebraska Center for Research on Children, Youth, Families, and Schools: Faculty Publications

The importance of early and developmentally appropriate science education is increasingly recognized. Consequently, creation of common guidelines and standards in early childhood science education has begun (National Research Council (NRC), 2012), and researchers, practitioners, and policy makers have shown great interest in aligning professional development with the new guidelines and standard. There are some important issues that need to be addressed in order to successfully implement guidelines and make progress toward accomplishing standards. Early childhood teachers have expressed a lack of confidence in teaching science and nature (Torquati, Cutler, Gilkerson, & Sarver, in press) and have limited science and pedagogical …