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Articles 1771 - 1800 of 2277

Full-Text Articles in Civil and Environmental Engineering

Measuring Performance Of Innovative Pavement Features, Wayne Jensen, Zhigang Shen, Cody Kluver Jan 2009

Measuring Performance Of Innovative Pavement Features, Wayne Jensen, Zhigang Shen, Cody Kluver

Department of Construction Engineering and Management: Faculty Publications

The Nebraska Department of Roads (NDOR) conducts annual examinations of the state's interstate and federal highway pavements. During these examinations, numerous indicators of pavement performance are measured directly or compiled from parameters recorded by a vehicle passing over the pavement section. Parameters are documented and analyzed for each one-tenth mile pavement segment. Seven sections where innovative features have been incorporated into the pavement were selected by the NDOR for comparison to nearby conventional pavement sections. This study used various parameters recorded by the NDOR as well as field observations to compare the performance of seven pairs of pavement sections. Each …


Missouri River Recovery Program: Fish And Wildlife Protection – Key To A Healthy River Jan 2009

Missouri River Recovery Program: Fish And Wildlife Protection – Key To A Healthy River

United States Army Corps of Engineers, Omaha District

Fish and wildlife conservation on the Missouri River is one of the eight congressionally-authorized project purposes of the U.S. Army Corps of Engineers. In support of this, the Corps manages lands and waters to ensure its availability for future generations and to help preserve healthy ecosystems and biodiversity. This purpose originally focused on maintaining native and game species, but in recent years it has taken on renewed prominence with efforts to recover threatened and endangered species.

The Missouri River is a dynamic ecosystem, creating and maintaining important open water, sandbar, wetland, and forest habitat for a wide diversity of wildlife, …


Missouri River Recovery Program: Reclaiming Lost Habitat: Real Estate Program Jan 2009

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 …


Missouri River Recovery Program: River Power To Clean Energy Jan 2009

Missouri River Recovery Program: River Power To Clean Energy

United States Army Corps of Engineers, Omaha District

The overall vision of the Missouri River Recovery Program is to create a sustainable ecosystem supporting thriving populations of native species while providing for current social and economic values. Many of these social and economic values are authorized by the U.S. Congress as crucial uses of the river’s resources. Hydroelectric power is one of these authorized purposes. Hydroelectric power uses the power of the river to provide electricity to homes and businesses within the Missouri River Basin and beyond.


Missouri River Recovery Program: Missouri River Basin Jan 2009

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 Jan 2009

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 Jan 2009

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 …


Missouri River Recovery Program: Spring Rise Monitoring Jan 2009

Missouri River Recovery Program: Spring Rise Monitoring

United States Army Corps of Engineers, Omaha District

The U.S. Army Corps of Engineers is committed to recover Missouri River species, while fulfilling its century-old responsibility to protect human health and safety. To aid in the recovery of the endangered pallid sturgeon, the Corps releases extra water from Missouri River reservoirs in March and May. These “spring pulses” mimic the historic river rises that resulted from melting snow on the plains and mountains, before the construction of dams on the river. Biologists believe these pulse events are necessary for Missouri River species to reproduce and survive, which is critical for a healthy river environment.

At the same time, …


Grand Challenges For Biological Engineering, Jeong-Yeol Yoon, Mark R. Riley Jan 2009

Grand Challenges For Biological Engineering, Jeong-Yeol Yoon, Mark R. Riley

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Biological engineering will play a significant role in solving many of the world's problems in medicine, agriculture, and the environment. Recently the U.S. National Academy of Engineering (NAE) released a document "Grand Challenges in Engineering," covering broad realms of human concern from sustainability, health, vulnerability and the joy of living. Biological engineers, having tools and techniques at the interface between living and non-living entities, will play a prominent role in forging a better future. The 2010 Institute of Biological Engineering (IBE) conference in Cambridge, MA, USA will address, in part, the roles of biological engineering in solving the challenges presented …


Impact Of Microclimatic Data Measured Above Maize And Grass Canopies On Penman‐Monteith Reference Evapotranspiration Calculations, Suat Irmak, Lameck O. Odhiambo Jan 2009

Impact Of Microclimatic Data Measured Above Maize And Grass Canopies On Penman‐Monteith Reference Evapotranspiration Calculations, Suat Irmak, Lameck O. Odhiambo

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Estimation of reference evapotranspiration (ETref) using measured microclimatic data and the Penman‐Monteith (PM) method provides a powerful means of quantifying actual plant evapotranspiration (ETa) needed for use in various disciplines. When applying the PM method to estimate ETref, it is desirable to measure the required microclimatic data over a reference grass or alfalfa surface rather than above non‐reference surfaces. However, in reality, establishing and maintaining a reference surface for long periods of time is a difficult task. Other surface energy balance systems, such as the Bowen ratio energy balance system (BREBS), eddy covariance system, …


Special Issue On Evapotranspiration Measurement And Modeling, Samuel Ortega-Farias, Suat Irmak, R. H. Cuenca Jan 2009

Special Issue On Evapotranspiration Measurement And Modeling, Samuel Ortega-Farias, Suat Irmak, R. H. Cuenca

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Water availability for irrigation throughout the world has been reduced in recent years due to a combination of frequent droughts and competition for water resources among agricultural, industrial, and urban users. In addition, some major agricultural areas face moderate to significant reductions of rainfall, or changes in timing of stream flow due to changes in timing of snowmelt, as a result of global climate change. Under such conditions, sophisticated irrigation water management will be required to optimize water use efficiency and maintain sufficient levels of crop productivity and quality. A key factor to achieve these targets is the estimation of …


Magnitude And Trends Of Reference Evapotranspiration Rates In South Central Nebraska: Daily, Monthly, Growing Season Total, And Annual Total, Suat Irmak Jan 2009

Magnitude And Trends Of Reference Evapotranspiration Rates In South Central Nebraska: Daily, Monthly, Growing Season Total, And Annual Total, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Reference evapotranspiration (ETref ) is used to determine the actual water use (ETa) rate for various crops and is one of the key variables that needs to be determined accurately for effective irrigation management. This extension circular provides information on the magnitude and temporal distribution of daily, monthly, annual, and growing season alfalfa-reference evapotranspiration (ETref)) in south central Nebraska. It also discusses why long-term average ETref values may not represent non-average years or be accurate enough for irrigation management.

The most common way to calculate actual crop water use (ETa) for a …


Integration Of An Extended Octagonal Ring Transducer And Soil Coulterometer For Identifying Soil Compaction, Santosh Pitla, L. G. Wells, S. A. Shearer Jan 2009

Integration Of An Extended Octagonal Ring Transducer And Soil Coulterometer For Identifying Soil Compaction, Santosh Pitla, L. G. Wells, S. A. Shearer

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The soil coulterometer is an “on‐the‐go” electro‐mechanical system which collects impedance force data at multiple depths using an oscillating coulter. During the initial testing (summer 2006), only vertical soil impedance force data was collected using a pressure sensor. To improve the performance of the coulterometer, an extended octagonal ring transducer was integrated into the system to collect both the horizontal and vertical impedance forces given by the soil. In the summer of 2007, data was collected using the revised sensor from a typical central Kentucky field setting in a 0.8‐ha (2‐acre) plot. Four passes were made with the coulterometer. Seventy …


Estimating Percent Residue Cover Using The Line-Transect Method, David P. Shelton, Paul J. Jasa Jan 2009

Estimating Percent Residue Cover Using The Line-Transect Method, David P. Shelton, Paul J. Jasa

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Leaving crop residue on the soil surface is one of the easiest and most cost-effective methods of reducing soil erosion. Research in Nebraska and other midwestern states has shown that leaving as little as 20 percent of the soil surface covered with crop residue can reduce soil erosion by one-half of what it would be from residue-free conditions. Greater amounts of residue cover will further reduce erosion. Many Conservation Plans specify crop residue management or residue left on the soil surface as the primary erosion control method. Generally, the amount of cover required after planting ranges from 30 percent to …


Effect Of Phase Countdown Timers On Queue Discharge Characteristics Under Heterogeneous Traffic Conditions, Anuj Sharma Jan 2009

Effect Of Phase Countdown Timers On Queue Discharge Characteristics Under Heterogeneous Traffic Conditions, Anuj Sharma

Anuj Sharma Publications

Analysis of queue discharge characteristics at signalized intersections is a primary component of traffic signal analysis and design. On the basis of previous studies, mainly conducted in homogeneous traffic conditions, the discharge headway is assumed to be high at the start of green for the first few vehicles, mainly because of start-up lost times, and is also assumed to reach the minimum value by the fourth or fifth vehicle in the queue. The minimum headway is expected to continue until the end of the queue. However, this may not be the case under heterogeneous traffic conditions, such as those in …


Special Issue On Evapotranspiration Measurement And Modeling, Samuel Ortega-Farias, Suat Irmak, R. H. Cuenca Jan 2009

Special Issue On Evapotranspiration Measurement And Modeling, Samuel Ortega-Farias, Suat Irmak, R. H. Cuenca

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Water availability for irrigation throughout the world has been reduced in recent years due to a combination of frequent droughts and competition for water resources among agricultural, industrial, and urban users. In addition, some major agricultural areas face moderate to significant reductions of rainfall, or changes in timing of stream flow due to changes in timing of snowmelt, as a result of global climate change. Under such conditions, sophisticated irrigation water management will be required to optimize water use efficiency and maintain sufficient levels of crop productivity and quality. A key factor to achieve these targets is the estimation of …


Regional Co2 And Latent Heat Surface Fluxes In The Southern Great Plains: Measurements, Modeling, And Scaling, W. J. Riley, Sebastien C. Biraud, Margaret S. Torn, Marc L. Fischer, David P. Billesbach, Joe A. Berry Jan 2009

Regional Co2 And Latent Heat Surface Fluxes In The Southern Great Plains: Measurements, Modeling, And Scaling, W. J. Riley, Sebastien C. Biraud, Margaret S. Torn, Marc L. Fischer, David P. Billesbach, Joe A. Berry

Department of Agricultural and Biological Systems Engineering: Faculty Publications

[1] Characterizing net ecosystem exchanges (NEE) of CO2 and sensible and latent heat fluxes in heterogeneous landscapes is difficult, yet critical given expected changes in climate and land use. We report here a measurement and modeling study designed to improve our understanding of surface to atmosphere gas exchanges under very heterogeneous land cover in the mostly agricultural U.S. Southern Great Plains (SGP). We combined three years of site-level, eddy covariance measurements in several of the dominant land cover types with regional-scale climate data from the distributed Mesonet stations and Next Generation Weather Radar precipitation measurements to calibrate a land surface …


Development Of High Performance Precast/Prestressed Bridge Girders, Amin K. Akhnoukh Dec 2008

Development Of High Performance Precast/Prestressed Bridge Girders, Amin K. Akhnoukh

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

Demand continues to increase for bridges with long spans and shallow depths. Due to safety concerns, four-span overpasses are being replaced with two span overpasses to avoid placement of piers near the highway shoulders. In the meantime, the bridge profile is restricted due to existing businesses nearby. Thus, nearly the same superstructure depth must be used for double the span length. This dissertation focuses on topics aiming at providing precast prestressed concrete girders with the shallowest possible depth for a given span. It forms parts of larger projects conducted by the University of Nebraska for the Nebraska Department of Roads …


Integrated Science Assessment For Oxides Of Nitrogen And Sulfur – Ecological Criteria, United States Environmental Protection Agency Dec 2008

Integrated Science Assessment For Oxides Of Nitrogen And Sulfur – Ecological Criteria, United States Environmental Protection Agency

United States Environmental Protection Agency: Publications

This Integrated Science Assessment (ISA) is a synthesis and evaluation of the most policy-relevant science that forms the scientific foundation for the review of the secondary (welfare-based) national ambient air quality standards (NAAQS) for oxides of nitrogen (NOx) and oxides of sulfur (SOx). The Clean Air Act definition of welfare effects includes, but is not limited to, effects on soils, water, wildlife, vegetation, visibility, weather, and climate, as well as effects on man-made materials, economic values, and personal comfort and well-being. The current secondary NAAQS for SOx, set in 1973, is a 3-hour average …


Cable Median Barrier Guidelines, Dean L. Sicking, Karla A. Lechtenberg, Francisco Daniel Benicio De Albuquerque Dec 2008

Cable Median Barrier Guidelines, Dean L. Sicking, Karla A. Lechtenberg, Francisco Daniel Benicio De Albuquerque

Nebraska Department of Transportation: Research Reports

No abstract provided.


Approach Slope For Midwest Guardrail System, Erin A. Johnson, Karla A. Lechtenberg, Dean L. Sicking, Robert W. Bielenberg M.S.C.E., E.I.T., Ronald K. Faller, John R. Rohde, John D. Reid Dec 2008

Approach Slope For Midwest Guardrail System, Erin A. Johnson, Karla A. Lechtenberg, Dean L. Sicking, Robert W. Bielenberg M.S.C.E., E.I.T., Ronald K. Faller, John R. Rohde, John D. Reid

Nebraska Department of Transportation: Research Reports

No abstract provided.


Quantitative Rrna-Targeted Solution-Based Hybridization Assay Using Peptide Nucleic Acid Molecular Beacons, Xu Li, Eberhard Morgenroth, Lutgarde Raskin Dec 2008

Quantitative Rrna-Targeted Solution-Based Hybridization Assay Using Peptide Nucleic Acid Molecular Beacons, Xu Li, Eberhard Morgenroth, Lutgarde Raskin

Department of Civil and Environmental Engineering: Faculty Publications

The potential of a solution-based hybridization assay using peptide nucleic acid (PNA) molecular beacon (MB) probes to quantify 16S rRNA of specific populations in RNA extracts of environmental samples was evaluated by designing PNA MB probes for the genera Dechloromonas and Dechlorosoma. In a kinetic study with 16S rRNA from pure cultures, the hybridization of PNA MB to target 16S rRNA exhibited a higher final hybridization signal and a lower apparent rate constant than the hybridizations to nontarget 16S rRNAs. A concentration of 10 mM NaCl in the hybridization buffer was found to be optimal for maximizing the difference between …


Performance Evaluation Of Safety Grates For Cross-Drainage Culverts, Karla A. Polivka, Dean L. Sicking, Robert W. Bielenberg, John R. Rohde, Ronald K. Faller, John D. Reid Oct 2008

Performance Evaluation Of Safety Grates For Cross-Drainage Culverts, Karla A. Polivka, Dean L. Sicking, Robert W. Bielenberg, John R. Rohde, Ronald K. Faller, John D. Reid

Nebraska Department of Transportation: Research Reports

No abstract provided.


Application Of The Modified Log-Wake Law In Open-Channels, Junke Guo, Pierre Y. Julien Sep 2008

Application Of The Modified Log-Wake Law In Open-Channels, Junke Guo, Pierre Y. Julien

Department of Civil and Environmental Engineering: Faculty Publications

The modified log-wake law, which was developed for turbulent boundary layers and pipe flows, is extended to turbulent flows in open-channels. Turbulent velocity profiles in open-channels can be approximated with three components: (1) the law of the wall that results from the constant bed shear stress; (2) the law of the wake that reflects the effects of gravity, secondary currents and bed roughness; and (3) the cubic correction near the maximum velocity. A procedure to determine the four model parameters from velocity measurements while keeping κ = 0.41 is presented. The modified log-wake law compares very well with experimental data …


Implementing Scc Technology In Nebraska—All About Working Together, Mark D. Lafferty Aug 2008

Implementing Scc Technology In Nebraska—All About Working Together, Mark D. Lafferty

Department of Civil and Environmental Engineering: Faculty Publications

In October 2001, Concrete Industries, Inc. (CI) was working with its admixture supplier to improve our form finish for precast concrete products. They brought us a new product and before long the concrete slump became a 26‐in. (660‐mm) diameter circle. Obviously, this generated a lot of excitement with our production personnel, but we also had to consider what it would take to get architects and engineers comfortable with using it.


Facilitating Use Of The Odor Footprint Tool By Nebraska Pork Producers, Rick R. Stowell Jul 2008

Facilitating Use Of The Odor Footprint Tool By Nebraska Pork Producers, Rick R. Stowell

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The goal of this project was to make Odor Footprint Tool (OFT) resources readily usable by pork producers and their technical advisors as a planning and screening tool when siting swine facilities. Detailed odor footprints for five specified sizes of swine facilities were developed for twenty-four locations throughout Nebraska: six regional sites and three “localized” sites within each region. Each odor footprint shows the predicted odor annoyance-free frequency as a function of the distance from the facility. Footprints developed using localized weather data differed only slightly from footprints produced using weather data from a regional site when the general topography …


Integrated Science Assessment For Oxides Of Nitrogen — Health Criteria, U.S. Environmental Protection Agency Jul 2008

Integrated Science Assessment For Oxides Of Nitrogen — Health Criteria, U.S. Environmental Protection Agency

United States Environmental Protection Agency: Publications

National Ambient Air Quality Standards (NAAQS) are promulgated by the U.S. Environmental Protection Agency (EPA) to meet requirements set forth in Sections 108 and 109 of the Clean Air Act (CAA). These sections require the EPA Administrator (1) to list widespread air pollutants that reasonably may be expected to endanger public health or welfare; (2) to issue air quality criteria that assess the latest available scientific information on the nature and effects of ambient exposure to the criteria pollutants; (3) to set “primary” NAAQS to protect human health with adequate margin of safety and to set “secondary” NAAQS to protect …


Nebraska Water Map Jul 2008

Nebraska Water Map

Nebraska Water Center: Administrative Materials

Nebraska Water is a full-color, 24"x36" poster, that is appropriate for educational use. The information presented on the maps is the best available as of July 2008. The content and level of detail of each map is based on available space and map scale.


Design And Evaluation Of A Low-Tension Cable Guardrail End Terminal System, Rebecca A. Hitz, Kirk J. Molacek, Cody S. Stolle, Karla A. Polivka, Ronald K. Faller, John R. Rohde, Dean L. Sicking, John D. Reid Jul 2008

Design And Evaluation Of A Low-Tension Cable Guardrail End Terminal System, Rebecca A. Hitz, Kirk J. Molacek, Cody S. Stolle, Karla A. Polivka, Ronald K. Faller, John R. Rohde, Dean L. Sicking, John D. Reid

Nebraska Department of Transportation: Research Reports

No abstract provided.


Implementation Of Conductive Concrete For Deicing (Roca Bridge), Christopher Y. Tuan Jul 2008

Implementation Of Conductive Concrete For Deicing (Roca Bridge), Christopher Y. Tuan

Nebraska Department of Transportation: Research Reports

No abstract provided.