Engineering Commons^™

Effects Of Aggregates On Properties And Performance Of Mastics And Superpave Hot Mix Asphalt Mixtures, Francisco Aragão

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Superpave, a set of advancements in testing devices and specifications for asphalt binders and mixtures, was limited to address the effects of aggregates. Because aggregates represent around 95% in mass of the asphalt mixtures, it is important to understand how these materials affect properties and performance of such mixtures. This research focus on how different types and contents of aggregates affect properties of mastics and asphalt mixtures, and their performance considering the viscoelastic nature of the asphalt material.

Five different types of aggregates and hydrated lime were used for sample fabrication together with two different binders. Several different tests were …

Measurement Of Poisson’S Ratio With Contact-Resonance Atomic Force Microscopy, D.C. Hurley, Joseph A. Turner

Nebraska Center for Materials and Nanoscience: Faculty Publications

We describe contact-resonance atomic force microscopy (AFM) methods to quantitatively measure Poisson’s ratio ν or shear modulus G at the same time as Young’s modulus E. In contact-resonance AFM, the frequencies of the cantilever’s resonant vibrations are measured while the tip is in contact with the sample. Simultaneous measurement of flexural and torsional vibrational modes enables E and ν to be determined separately. Analysis methods are presented to relate the contact-resonance frequencies to the tip-sample contact stiffness, which in turn determines the sample’s nanoscale elastic properties. Experimental results are presented for a glass specimen with fused silica used as …

Wireless Multiple Access Communication Over Collision Frequency Shift Channels, Chen Xia

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

A collision frequency shift keyed system (CFSK) using M-ary FSK signaling is investigated. CFSK is a wireless multiple access system in which users access a channel without cooperation. This results in collisions when users simultaneously transmit signals in the same frequency band. However, analysis has shown that the CFSK system has the potential to achieve greater capacities than binary multiple access systems.

In this dissertation, bounds on the multiuser capacity of the noisy synchronous and asynchronous CFSK channel are derived. Analytical models are designed for investigating these capacity results. It is shown that the capacity of the noisy synchronous CFSK …

Ellipsometer Or Polarimeter And The Like System With Multiple Detector Element Detector In Environmental Control Chamber Including Secure Sample Access, John A. Woollam, Gregory K. Pribil, Martin M. Liphardt, James Welch

Department of Electrical and Computer Engineering: Faculty Publications

A spectrophotometer, ellipsometer or polarimeter or the like system with a spectroscopic source of wavelengths and a detector with multiple detector elements for simultaneous monitoring of a number of wavelengths in an environmental control chamber which optionally provides for secured sample entry, and methodology of use.

Acuta Enews August 2007, Vol. 36, No. 8

ACUTA Newsletters

ln This lssue

From the President ............. Walt Magnussen, Ph,D., Texas A&M University

Tech Talk: ls This a Phone That You Want on Your Network? ............ Kevin Tanzillo, Dux PR 2 ACUTA Resources Make Membership a Great Value

DC Update ............... Jeanne Jansenius, Sewonee, The University of the South

Board Report............... Riny Ledgerwood, San Diego State Univ., ACUTA Sec./Treasurer

IPFIX Standard (NetFlow) and lT Staff |mpact.............. Gary Audin, Delphi lnc.

Check lt Out: RFls/RFPs, Job Postings, Press Releases

FYI: Useful lnformation from the Campus................. Student Monitor

Web Tip: Address Change for ACUTA Listservs ..... Aaron Fuehrer, ACUTA lnformation Technology Mgr. …

Design Aids For Threaded Rod Precast Prestressed Girder Continuity System, Maher K. Tadros, Leslie D. Martin

Nebraska Department of Transportation: Research Reports

No abstract provided.

Quantum Ballistics, Andrei Sokolov

Materials Research Science and Engineering Center: Faculty Publications

For the last 40 years, computer-chip manufacturers have been constantly improving the performance of their products by shrinking the size of transistors—the building blocks of processors and memory chips. Having gone from dimensions of a few microns in the early 1970s to 45 nm in Intel’s latest prototypes, the number of transistors that can be etched on a given area of silicon has been doubling every 18 months. This exponential trend, which is known as Moore’s law, has been the driving force behind the relentless miniaturization of microelectronic devices. However, we are now approaching the physical limits of existing technology. …

Streambank Stabilization Using Traditional And Bioengineering Methods:A Literature Review, David M. Admiraal

Nebraska Department of Transportation: Research Reports

No abstract provided.

Nitrogen And Phosphorus Concentrations Of Runoff As Affected By Moldboard Plowing, John E. Gilley, Bahman Eghball, David B. Marx

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The excessive application of manure on cropland areas can cause nutrients to accumulate near the soil surface. This study was conducted to measure the effects of moldboard plowing on the redistribution of nutrients within the soil profile and nutrient transport by overland flow. Composted beef cattle manure was applied at dry weights of 0, 68, 105, 142, and 178 Mg ha^-1 to a silty clay loam soil and then incorporated by disking. Selected plots were moldboard plowed 244 days later to a depth of approximately 23 cm. Soil samples for analysis of water‐soluble phosphorus, Bray and Kurtz No. 1 …

Nutrient Concentrations Of Runoff During The Year Following Manure Application, John E. Gilley, Bahman Eghball, D. B. Marx

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Little information is currently available concerning temporal changes in nutrient transport following the addition of manure to cropland areas. This study was conducted to measure nutrient transport in runoff as affected by tillage and time following the application of beef cattle or swine manure to a site on which corn (Zea mays L.) was grown. Rainfall simulation tests were initiated 4, 32, 62, 123, and 354 days following land application. Three 30 min simulated rainfall events, separated by 24 h intervals, were conducted at an intensity of approximately 70 mm h-1. Dissolved phosphorus (DP), particulate phosphorus (PP), total phosphorus …

Combined Spatial Filter And Relay Systems In Rotating Compensator Ellipsometer/Polimeter, Martin M. Liphardt, Blaine D. Johs, Jeffrey S. Hale, Craig M. Herzinger, Steven E. Green, Ping He, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

Low aberration relay systems modified to perform as spatial filters in rotating compensator ellipsometer, polarimeter and the like systems.

Understanding Sub-20 Nm Breakdown Behavior Of Liquid Dielectrics, Kumar R. Virwani, Ajay P. Malshe, Kamlakar P. Rajurkar

Department of Industrial and Management Systems Engineering: Faculty Publications

Nanoscale confinement of dielectric molecules is expected to influence their breakdown mechanism in applications such as nanoprobe based machining, molecular electronics, and other related technologies. This Letter presents the first experimental study of the breakdown of nonpolar, nonthiolated liquid dielectrics in the nanometer regime and develops a field emission assisted avalanche based approach to model such behavior. The studies show that dielectric breakdown in the sub-20 nm regime is independent of the cathode materials and is dominated by the electron emission and atomic cluster migration due to the ‘‘sub-20 nm scale confinement of the liquid dielectric.’’

Detection Of Ultrathin Biological Films Using Vacuum Ultraviolet Spectroscopic Ellipsometry, Dileep K. Goyal, Greg K. Pribil, John A. Woollam, Anuradha Subramanian

Anuradha Subramanian Publications

Spectroscopic ellipsometry (SE) is a non-contact and a non-destructive optical technique used in characterization of thin films. It is widely used to determine optical constants, thickness in multilayer stacks and microstructure (voids, alloy fraction, or mixed phase composition). This paper reports on a systematic investigation of the optical properties of two different kinds of silane compounds: 3-aminopropyltriethoxysilane (APTES) and 3-glycidoxypropyltriethoxy-silane (GPS) as well as for immunoglobulin G (IgG) attached to these modified samples using vacuum ultraviolet spectroscopic ellipsometry (VUV-SE). VUV-SE is a newly developed technique and used to evaluate the strength and energy of the interband electronic excitations/transitions in these …

Acuta Enews July 2007, Vol. 36, No. 7

ACUTA Newsletters

ln This lssue

Meet the Board for 2007-08

From ACUTA Headquarters: Member Anniversaries............... Jeri A. Semer, CAE, Executive Director

Tech Talk: The Passing of Passwords................... Kevin Tanzillo, Dux PR

DC Update .................. Jeanne Jansenius, Sewanee, The University of the South

Check lt Out: RFls/RFPs, Job Postings, Press Releases

Board Report ................. Riny Ledgerwood, Son Diego State Univ., ACUTA Sec./Treasurer

FYI: Useful lnformation from the campus............... Student Monitor

Level 3 Completes lnternet2 Optical Network implementation

Member Sites to See

lnfo Links................... Randy Hayes, Univ. of Northern lowa

Terri Robinett Wins Room at the Conference

$5250,000 Emergency & Event Notification "Grants,, from …

Blowout Penstemon (Penstemon Haydenil) Endangered Species, James Stubbendieck, Kay Lynn Kottas

Nebraska Department of Transportation: Research Reports

No abstract provided.

Global-Change Scenarios: Their Development And Use, Edward Parson, Virginia Burkett, Karen Fisher-Vanden, David Keith, Linda Mearns, Hugh Pitcher, Cynthia Rosenzweig, Mort Webster

United States Department of Energy: Publications

A scenario is a description of potential future conditions produced to inform decision-making under uncertainty. Scenarios can help inform decisions that involve high stakes and poorly characterized uncertainty, which may thwart other, conventional forms of analysis or decision support. Originally developed to study military and security problems, scenarios are now widely used for strategic planning and assessment in businesses and other organizations, and increasingly to inform planning, analysis, and decision-making for environmental issues, including climate change.
Scenarios can serve many purposes. They can help inform specific decisions, or can provide inputs to assessments, models, or other decision-support activities when these …

Scenarios Of Greenhouse Gas Emissions And Atmospheric Concentrations, Leon Clarke, James Edmonds, Henry Jacoby, Hugh Pitcher, John Reilly, Richard Richels

United States Department of Energy: Publications

This and a companion report constitute one of twenty-one Synthesis and Assessment Products called for in the Strategic Plan for the U.S. Climate Change Science Program. These studies are structured to provide high-level, integrated research results on important science issues with a particular focus on questions raised by decision-makers on dimensions of climate change directly relevant to the U.S. One element of the CCSP’s strategic vision is to provide decision support tools for differentiating and evaluating response strategies. Scenario-based analysis is one such tool. The scenarios in this report explore the implications of alternative stabilization levels of anthropogenic greenhouse …

Convergence Or Divergence: Technology Policies And User Expectations

ACUTA: Other Publications

The Forum

Since 1997, the annual ACUTA Forum for Strategic Leadership in Communications Technology has provided a unique opportunity for campus leaders to exchange ideas and discuss issues relevant to the use of technology in meeting the goals of higher education. Held in conjunction with ACUTA's Annual Conference and Exhibtion, this forum brings together men and women of vision, foresight, and authority to discuss strategic directions for the campus of the future.

Goals

• To provide a venue for the examination of issue and challenges facing the higher education community as we grapple with planning, financing, and implementing technology on our …

Nebraska Blueprint - Summer 2007

Nebraska Blueprint (Student Publication)

Table of Contents:

Engineering Alumni Join Peace Corps: Volunteers give back to society by teaching others applicable engineering skills. by Natasha Richardson
Graduate’s Career Lets him Explore Sea and Space: Don Skoumal has notable achievements and involvement in NASA’s Sea Launch Project. by Brian Neilson
Applying Nanotechnology to Tanks: Dean David Allen’s research is helping make tanks lighter and stronger. by Kellie Troxel
A Treatment for Hemophilia Could Start Here: Researchers look for a new treatment to combat this dangerous blood disorder. by Michaela McBride
10 Ways to Get the Most out of Engineering at UNL: A soon-to-be graduate gives …

Pilot Study On Real-Time Calculation Of Arrival Type For Assessment Of Arterial Performance, Edward J. Smaglik, Darcy M. Bullock, Anuj Sharma

Department of Civil and Environmental Engineering: Faculty Publications

The Highway Capacity Manual uses the arrival type (AT) as a mechanism to account for the quality of traffic signal coordination in the calculation of delay at a signalized intersection. Although there is much discussion in the literature regarding the accuracy and precision of this approach, the AT parameter provides a simple mechanism for grading the performance of traffic signal coordination. This paper describes data collection limitations of current traffic signal controllers and proposes a procedure where the AT parameter can be calculated by traffic signal controllers in real time. Given that the nation received a score of 61 out …

Vacuum Ultraviolet Optical Analysis Of Spin-Cast Chitosan Films Modified By Succinic Anhydride And Glycidyl Phenyl Ether, William H. Nosal, Daniel W. Thompson, T. E. Tiwald, S. Sarkar, Anuradha Subramanian, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

Optical properties of spin-cast chitosan films were determined in the vacuum ultraviolet (VUV) through visible regions of the spectrum using spectroscopic ellipsometry. The onset of absorption in the ultraviolet was determined for chitosan films modified with succinic anhydride (SA) and glycidyl phenyl ether (GPE). This absorption was accounted for by including Gaussian and Tauc–Lorentz shaped oscillators in the optical model. VUV through visible optical constants were determined for these modified films, as well as for immunoglobulin G (IgG) attached to GPE-modified samples. Several resonant oscillator structures exhibit greatly differing oscillator parameters for the as-deposited, as well as SA- and GPE …

Water Erosion Prediction Project (Wepp): Development History, Model Capabilities, And Future Enhancements, Dennis C. Flanagan, John E. Gilley, Thomas G. Franti

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The Water Erosion Prediction Project (WEPP) was initiated in August 1985 to develop new‐generation water erosion prediction technology for use by federal action agencies involved in soil and water conservation and environmental planning and assessment. Developed by the USDA‐ARS as a replacement for empirically based erosion prediction technologies, the WEPP model simulates many of the physical processes important in soil erosion, including infiltration, runoff, raindrop and flow detachment, sediment transport, deposition, plant growth, and residue decomposition. The WEPP project included an extensive field experimental program conducted on cropland, rangeland, and disturbed forest sites to obtain data required to parameterize and …

Laying The Groundwork For Odor Control And Setback Estimation In Nebraska, Rick R. Stowell

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The goal of this field research study was to validate use of the Odor Footprint Tool (OFT) with livestock building sources in rural communities. The primary objective was to evaluate the accuracy of predictions of annoyance potential (as projected by odor concentration output data from AERMOD^® - the OFT's underlying dispersion model) when compared to measures of annoyance potential made in the field. Odor assessors were trained to monitor odors around a 4,800-head finishing site in eastern Nebraska. During the summer of 2005, mobile odor assessors monitored odor levels at downwind locations. During the spring and summer of 2006, …

Adhesive Contact In Filaments, Xiang-Fa Wu, Yuris A. Dzenis

Department of Engineering Mechanics: Faculty Publications

This paper studies the elastic contact in filaments induced by surface adhesion, which plays an important role in the mechanical response of fibrous materials (e.g., fiber friction, sliding, compression hysteresis, etc.). During the process, a simple 3D elastic contact model was proposed. The filaments were assumed to be uniform, smooth elastic cylinders, and the adhesive force between filaments in contact was estimated according to Bradley’s approach (Bradley 1932 Phil. Mag. 13 853) that relies on the filament configurations before deformation. Under the action of fiber surface adhesion, the elastic deformation and the size of the contact zone were determined in …

Temporal Changes In Nutrient Transport Following Land Application Of Manure, John E. Gilley, Eghball Bahman, D. B. Marx

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

Little information is currently available concerning temporal changes in nutrient transport following the addition of manure to cropland areas. This study was conducted to measure nutrient transport in runoff as affected by tillage and time following the application of beef cattle or swine manure to a site on which corn [Zea mays (L.)] was grown. Rainfall simulation tests were initiated 4, 32, 62, 123, and 354 days following land application. Three 30-min simulated rainfall events, separated by 24-hour intervals, were conducted at an intensity of approximately 70 mm hr-1. Dissolved phosphorus (DP), particulate phosphorus (PP), total phosphorus (TP), NO3-N, …

Runoff Nutrient Concentrations Following Manure Application As Affected By Crop Residue, John E. Gilley, Jeffrey Nicolaisen, Eghball Bahman, David B. Marx

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

Manure is applied to cropland areas managed under diverse conditions resulting in varying amounts of residue cover. The objective of this study was to measure the effects of crop residue on nutrient concentrations in runoff from areas where beef cattle or swine manure were recently applied but not incorporated. Plots 0.75 m wide by 2 m long were established at the study site. Existing residue materials were removed, and corn, soybean, or winter wheat residue was added at rates of 2, 4, or 8 Mg ha-1. Manure was applied at rates required to meet estimated annual nitrogen requirements for corn. …

Moldboard Plowing Following Compost Application Significantly Reduces Nutrient Transport, John E. Gilley, Bahman Eghball, David B. Marx

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

The excessive application of manure on cropland areas can cause nutrients to accumulate near the soil surface and increase nutrient transport by overland flow. Inverting soils with high surface nutrient content could reduce runoff nutrient transport. This study was conducted to measure the effects of moldboard plowing on the redistribution of nutrients within the soil profile and nutrient transport by overland flow. Composted beef cattle manure was applied at dry weights of 0, 68, 105, 142, and 178 Mg ha^-1 to a silty clay loam soil and then incorporated by disking. Selected plots were moldboard plowed 244 days later …

Effect Of Overland Flow Rate On Nutrient Transport From Land Application Areas, John E. Gilley, William F. Sabatka, Bahman Eghball, David B. Marx

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

Little information is currently available concerning the effects of varying flow rate on nutrient transport by overland flow. The objective of this study was to measure the effects of overland flow rate on nutrient transport following the application of beef cattle or swine manure to plots containing 0, 2, 4, or 8 Mg ha^-1 of corn residue. After addition of residue materials to 0.75 m wide x 2.0 m long plots, beef cattle or swine manure was added and the plots were then either disked or maintained in a no-till condition. Three 30-min simulated rainfall events, separated by 24-hour …

Microwave Pretreatment Of Switchgrass To Enhance Enzymatic Hydrolysis, Deepak R. Keshwani, Jay J. Cheng, Joseph C. Burns, Laigeng Li, Vincent Chiang

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

Switchgrass is a promising lignocellulosic biomass for fuel-ethanol production. However, pretreatment of lignocellulosic materials is necessary to improve its susceptibility to enzymatic hydrolysis. The objectives of this study were to examine the feasibility of microwave pretreatment to enhance enzymatic hydrolysis of switchgrass and to determine the optimal pretreatment conditions. Switchgrass samples immersed in water, dilute sulfuric acid and dilute sodium hydroxide solutions were exposed to microwave radiation at varying levels of radiation power and residence time. Pretreated solids were enzymatically hydrolyzed and reducing sugars in the hydrolysate were analyzed. Microwave radiation of switchgrass at lower power levels resulted in more …

Collapse Analysis Of Nanofibers, Xiang-Fa Wu, Yuris A. Dzenis

Department of Engineering Mechanics: Faculty Publications

Continuous nanofibers fabricated by the electrospinning technique have found increasing applications (e.g., nanofiber composites, nanofiber devices, bioengineering tissue scaffolding, etc.). For a nanofiber network subjected to a small external perturbation, the fiber segments within the network may deflect and stick to each other under the condition that their surface adhesion energy overcomes the elastic strain energy induced by fiber bending. Therefore, this paper aims to study adhesion-induced nanofiber collapse and relevant criteria. A simple fiber collapse model was proposed, which is based on the contact of two deflected elastic filaments under surface adhesion. Four fundamental fiber collapse modes (i.e., fiber-flat …