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2008

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Articles 1 - 30 of 997

Full-Text Articles in Civil and Environmental Engineering

Improving The Design Of Low Volume Sealed Roads In Tanzania, Mfinanga A Dec 2008

Improving The Design Of Low Volume Sealed Roads In Tanzania, Mfinanga A

Tanzania Journal of Engineering and Technology (TJET)

The main objective of the study was to identify appropriate road designs for Low Volume Sealed Roads (LVSRs) with the aim of improving the design of such roads in Tanzania. The study was conducted in Dar es Salaam and Morogoro regions in Tanzania where data for LVSRs were collected from primary and secondary sources in the two regions. The study found that by using an improved pavement design method specifically meant for LVSRs results in cost savings for LVSRs of up to 51% compared with the conventional method of pavement design in Tanzania. The study recommends that the pavement design …

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Integrated Remote Sensing And Gis Techniques For Groundwater Exploration In Semi-Arid Region: A Case Of Karamoja Region – Uganda, Lubang Nobert Dec 2008

Integrated Remote Sensing And Gis Techniques For Groundwater Exploration In Semi-Arid Region: A Case Of Karamoja Region – Uganda, Lubang Nobert

Tanzania Journal of Engineering and Technology (TJET)

Groundwater is a precious resource that covers wide geographical extent. Proper evaluation is required in order to ensure prudent use of groundwater resources. The current groundwater assessment in Karamoja region, as in many parts of the world, uses Apparent Resistivity and Vertical Electrical Sounding, which has limited coverage to some localized usually predetermined areas. Comprehensive groundwater development program needs a wide area coverage and large volume of multidisciplinary data. In the present study, an integrated remote sensing and GIS based methodology is developed and tested for the evaluation of groundwater resources of Karamoja Sub Region, Northeastern Uganda. The components of …

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Potential Use Of Waterguard As A Disinfectant For Domestic Water Use, Yohana L Dec 2008

Potential Use Of Waterguard As A Disinfectant For Domestic Water Use, Yohana L

Tanzania Journal of Engineering and Technology (TJET)

been identified as an alternative method for treatment of domestic drinking water. The aim of this study was to investigate the effectiveness of Water Guard in disinfecting drinking water from different sources drawn from Kinondoni district, Dar es Salaam as well as to establish appropriate dosage that can be used during the treatment. Results showed that, a dose of 4.0mL per 20 litrer of water guard is sufficient for disinfection of urban water sources. The above prescribed doses provide 100% disinfection efficiency with residue chlorine of less than 0.3mg/l. Water with turbidity values of 30-35 NTU, chlorine dosage of 8mL/20 …

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The Multivariate Statistical Analysis Of Abiotic Parameters Of The Lake Tanganyika Sub Catchment, Hudson Nkotagu Dec 2008

The Multivariate Statistical Analysis Of Abiotic Parameters Of The Lake Tanganyika Sub Catchment, Hudson Nkotagu

Tanzania Journal of Engineering and Technology (TJET)

Results from multivariate statistical analysis of abiotic parameters conducted during the dry season at 20 accessible sites on 8 rivers, 2 lakes and a dam covering the Lake Tanganyika sub catchment are discussed. Standard methods were used to determine the levels of abiotic parameters from water samples. Physical parameters including DO, EC, Eh, turbidity, temperature, pH and secchi transparency were measured in situ while chlorophyll a was determined in the laboratory. Nutrients such as NO3-, SiO2, PO4 3- and Fe2+ were determined along with HCO3-. Factor analysis resulted in four factors including increased primary productivity, redox conditions, dissolution, and reduction …

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An Equation For Estimating The (R) Usle Slope Steepness Factors, Mathew Mulemgera Dec 2008

An Equation For Estimating The (R) Usle Slope Steepness Factors, Mathew Mulemgera

Tanzania Journal of Engineering and Technology (TJET)

Abstract Currently three equations are used for calculating slope steepness factor for the Revised Universal Soil Loss Equation (RUSLE); one for slopes less than nine percent, the second for slopes equal or greater than nine percent, and the third equation that has been proposed for use in China for slopes equal or greater than 17 %. The three equations have linear relationships between slope steepness factor, S and the sine of the slope angle, θ. The three equations under predict the factor, S when used on slope steepness beyond the data sets used to develop them. In addressing this problem …

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2008 Fall Engr333 Project Final Report, 2008 Fall Engr333 Dec 2008

2008 Fall Engr333 Project Final Report, 2008 Fall Engr333

ENGR 333

The Calvin College Engineering 333 class of 2008 was challenged with the question, “What would it take to implement an energy efficiency fund at Calvin?” Before addressing this question, another had to be asked: “What is an energy efficiency fund?” An energy efficiency fund is a revolving fund which takes seed money from donations, tuition, or grants and invests it into projects that save energy. Energy cost savings from the projects are routed back to the fund to help it grow and enable it to finance future projects. In order to begin this, the senior engineering students began organizing and …

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Assessment Of Ground Shaking In Ilan County, Taiwan, Hui-Mi Hsu, Sao-Jeng Chao, Howard Hwang Dec 2008

Assessment Of Ground Shaking In Ilan County, Taiwan, Hui-Mi Hsu, Sao-Jeng Chao, Howard Hwang

Journal of Marine Science and Technology–Taiwan

This paper presents an estimation of ground shaking intensity in the Ilan area caused by two scenario earthquakes. On the basis of seismic activity in the study area, the seismic zones, including Okinawa trough seismic zone section A and Suao-Hualien offshore seismic zone are established. The earthquakes occurring in these two zones are considered as the scenario earthquakes. The hundreds of boring logs are also collected and classified into three site classes as specified in the Taiwan Seismic Building Code. The intensity of ground shaking in the Ilan area caused by a scenario earthquake is then estimated by using an …

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Impact Of Fire-Through And Misfire In Rectifier Valves On A Turbine Generator Neighboring To A Hvdc Inverter Station, Ming-Te Liang Dec 2008

Impact Of Fire-Through And Misfire In Rectifier Valves On A Turbine Generator Neighboring To A Hvdc Inverter Station, Ming-Te Liang

Journal of Marine Science and Technology–Taiwan

The major purpose of this paper is the theoretical elucidation of the corrosion tube growth mechanism of mild steel occurred from the effect of pH value and oxygen corrosion at elevated pressure provided by Riggs et al. [6]. Based on the Nernst-Planck equation, continuity principle, Green's theorem, Stokes's theorem and the equation of Newton's second law of motion, the mechanism of corrosion tube development can be explained theoretically. The Bernoulli sum is contant at any cross-section of tubular corrosion product. The implication of the present results are theoretically enhanced the formation of corrosion tube mechanism.

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The Study Of Price Accept Threshold For The ??Lue Highway??Tour Of The North-East Region In Taiwan, Hung-Yen Chou, Jin-Long Lu, Chiang Fu Dec 2008

The Study Of Price Accept Threshold For The ??Lue Highway??Tour Of The North-East Region In Taiwan, Hung-Yen Chou, Jin-Long Lu, Chiang Fu

Journal of Marine Science and Technology–Taiwan

The “Blue Highway” in the NE region of Taiwan includes the tour itineraries of Keelung-Suao, Suao-Hualien and Keelung-Hualien, each with its individual oceanic scenic features and its potential corresponding onshore scenic spots. This study explores the relationship between the “Blue Highway” tour portfolios and price attributes to collect the preference recognition of the public concerning the NE region “Blue Highway” tour itineraries and prices with the stated preference method. The utility function of the discrete choice model assumes the impact effect among attributes to be in a linear relationship plus percentages. The price threshold model improves the assumption of this …

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Theoretical Elucidation On The Corrosion Tube Growth Mechanism Of Mild Steel In The Effect Of Ph On Oxygen Corrosion At Elevated Pressures, Ming-Te Liang Dec 2008

Theoretical Elucidation On The Corrosion Tube Growth Mechanism Of Mild Steel In The Effect Of Ph On Oxygen Corrosion At Elevated Pressures, Ming-Te Liang

Journal of Marine Science and Technology–Taiwan

The major purpose of this paper is the theoretical elucidation of the corrosion tube growth mechanism of mild steel occurred from the effect of pH value and oxygen corrosion at elevated pressure provided by Riggs et al. [6]. Based on the Nernst-Planck equation, continuity principle, Green's theorem, Stokes's theorem and the equation of Newton's second law of motion, the mechanism of corrosion tube development can be explained theoretically. The Bernoulli sum is contant at any cross-section of tubular corrosion product. The implication of the present results are theoretically enhanced the formation of corrosion tube mechanism.

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Case Study Of Wind-Resistant Design And Analysis Of High Mast Structures Based On Different Wind Codes, Ching-Wen Chien, Jing-Jong Jang Dec 2008

Case Study Of Wind-Resistant Design And Analysis Of High Mast Structures Based On Different Wind Codes, Ching-Wen Chien, Jing-Jong Jang

Journal of Marine Science and Technology–Taiwan

The high mast structure (HMS) has the characters of light weight and high cost efficiency. Therefore, it is widely used in the modern construction industry. It has a large the ratio of height (H) to least horizontal dimension (D) that makes it a particularly more slender and wind-sensitive than any other structures. Therefore, the purpose of this research is to develop the wind-resistant design (WRD) procedure for the slender, tapered support structures of HMS subjected to wind-induced excitation from vortex shedding and gust buffeting. This paper illustrates the theoretical basis and the analytical development of the WRD; including calculating gust …

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The Manpower Supply Planning And Shift Setting For Mass Rapid Transit Carriage Maintenance In Short-Term Operations, Shangyao Yan, Chia-Hung Chen, Miawjane Chen Dec 2008

The Manpower Supply Planning And Shift Setting For Mass Rapid Transit Carriage Maintenance In Short-Term Operations, Shangyao Yan, Chia-Hung Chen, Miawjane Chen

Journal of Marine Science and Technology–Taiwan

An effective carriage maintenance plan cannot only reduce the mass rapid transit system operating costs, but is also directly related to its safety and schedule punctuality. Traditionally, the arrangement of the carriage maintenance manpower supply has been based on staff experience, and has been performed manually following simple rules. This is not only time-consuming but often ineffective. Therefore, in this research, we incorporate flexible management strategies, different combinations of principles, and the related operating constraints, to develop a basic carriage maintenance manpower supply plan model. Furthermore, we construct an integrated model by modifying the basic model, which can help an …

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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 …

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Assessing Water Quality Modeling In Subtropical Regions Based On A Case Study Of The Aguamilpa Reservoir, Oliver Obregon Dec 2008

Assessing Water Quality Modeling In Subtropical Regions Based On A Case Study Of The Aguamilpa Reservoir, Oliver Obregon

Theses and Dissertations

The shortage of water in Mexico has made public and private institutions look at reservoirs as an alternative solution for present and future water supply. However, eighty percent of the existing reservoirs in Mexico are contaminated at some level, many severely. Water quality models are water-management tools used to diagnose water quality problems and the impact of various environmental conditions. They can be effective in assessing various measures of remediation leading to improved water quality. In most of the cases such water quality models have been successfully applied in reservoirs located in temperate climates. However, the use of water quality …

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Detection Of Voids In Prestressed Concrete Bridges Using Thermal Imaging And Ground-Penetrating Radar, David G. Pollock, Kenneth J. Dupuis, Benjamin Lacour, Karl R. Olsen Dec 2008

Detection Of Voids In Prestressed Concrete Bridges Using Thermal Imaging And Ground-Penetrating Radar, David G. Pollock, Kenneth J. Dupuis, Benjamin Lacour, Karl R. Olsen

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Thermal imaging and ground-penetrating radar was conducted on concrete specimens with simulated air voids. For the thermal imaging inspections, six concrete specimens were constructed during the month of June 2007 to simulate the walls of post-tensioned box girder bridges. The objective was to detect simulated air voids within grouted post-tensioning ducts, thus locating areas where the post-tensioning steel strands are vulnerable to corrosion. The most important deduction taken from these inspections was that PT-ducts and simulated voids were more detectable in the 20 cm (8 in.) thick specimens than in the 30 cm (12 in.) thick specimens. While inspections of …

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Hydro-Nexrad: An Updated Overview And Metadata Analysis, Witold F. Krajewski, Anton Kruger, Piotr Domaszczynski, Charles Gunyon, Bong Chul Seo, Radosław Goska, James A. Smith, Mary Lynn Beack, Matthias Steiner Dec 2008

Hydro-Nexrad: An Updated Overview And Metadata Analysis, Witold F. Krajewski, Anton Kruger, Piotr Domaszczynski, Charles Gunyon, Bong Chul Seo, Radosław Goska, James A. Smith, Mary Lynn Beack, Matthias Steiner

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Hydro-NEXRAD is a prototype system that allows hydrologists to obtain user-specified rainfall data for their research. These data are based on observations collected by the national network of WSR-88D radars, known as NEXRAD. Users interact with Hydro-NEXRAD through a web-based interface that has map-based components for spatial navigation, calendar- and time series plot components for temporal navigation and a menu-based component for selection of processing options. Through the interface, users browse the Hydro-NEXRAD metadata and select data of interest. As the system is approaching the point of being fully operational, the authors and a group of test users have evaluated …

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Liquefaction Behavior Of Mississippi River Silts, Ali M. Izadi, Ronaldo Luna, Richard Wesley Stephenson Dec 2008

Liquefaction Behavior Of Mississippi River Silts, Ali M. Izadi, Ronaldo Luna, Richard Wesley Stephenson

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Civil Infrastructure Built on Alluviums and Recent Deposits, Such as Dams, Contain Significant Amount of Silts. the Static and Dynamic Behavior of These Fine-Grained Soils Has Been Investigated Less Than the Clay-Like or Sand-Like Soils. Low Plasticity Silts (PI = 6) Obtained East of St. Louis in Illinois Are Known as Loess that Has Been Re-Deposited by Water in the Floodplains of the Mississippi River. These Silts Were Reconstituted in the Laboratory by Slurry at Water Content above the Liquid Limit and Then Consolidated to an Initial Effective Stress. the Initial Laboratory Characterization under Monotonic Loading Included a Series of …

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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 …

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Bs News Dec 2008

Bs News

Building Services Engineering

No abstract provided.

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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.

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How Can We Best Manage Freeway Congestion?, Robert Bertini, Christopher Monsere Dec 2008

How Can We Best Manage Freeway Congestion?, Robert Bertini, Christopher Monsere

TREC Project Briefs

Researchers from Portland State University evaluate Oregon’s Implementation of System-Wide Adaptive Ramp Metering (SWARM).

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Theoretical Determination Of Subcritical Sequent Depths For Complete And Incomplete Hydraulic Jumps In Closed Conduits Of Any Shape, Nathan John Lowe Dec 2008

Theoretical Determination Of Subcritical Sequent Depths For Complete And Incomplete Hydraulic Jumps In Closed Conduits Of Any Shape, Nathan John Lowe

Theses and Dissertations

In order to predict hydraulic jump characteristics for channel design, the jump height may be determined by calculating the subcritical sequent depth from momentum theory. In closed conduits, however, outlet submergence may fill the conduit entirely before the expected sequent depth is reached. This is called an incomplete or pressure jump (as opposed to a complete or free-surface jump), because pressure flow conditions prevail downstream. Since the momentum equation involves terms for the top width, area, and centroid of flow, the subcritical sequent depth is a function of the conduit shape in addition to the upstream depth and Froude number. …

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Operations-Oriented Performance Measures For Freeway Management Systems: Final Report, Robert E. Brydia, Stephen P. Mattingly, Melanie L. Sattler, Auttawit Upayokin Dec 2008

Operations-Oriented Performance Measures For Freeway Management Systems: Final Report, Robert E. Brydia, Stephen P. Mattingly, Melanie L. Sattler, Auttawit Upayokin

Civil Engineering Faculty Publications - Archive

This report describes the second and final year activities of the project titled “Using Operations-Oriented Performance Measures to Support Freeway Management Systems.” Work activities included developing a prototype system architecture for testing the use of performance measures in real-time. Outputs from this effort included operator’s screens, a prototype database, and a concept of operations for using the real-time measures. Additional work showcased the application of a multi-criterion screening approach to the selection of competing performance measures.

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Investigation Of The Merging Of Two Axisymmetric Turbulent Jets, Jeffrey Smith Dec 2008

Investigation Of The Merging Of Two Axisymmetric Turbulent Jets, Jeffrey Smith

All Theses

A study was done to determine the converging distance of two axisymmetric turbulent jets and to compare the experimental results with the Reichardt hypothesis. This experiment consisted of measuring the velocity profiles of the two jets and manipulating the momentum ratio between the jets. Through testing, it was determined that the Reichardt hypothesis while efficient, over predicts the converging distance of the jets by up to 25% in some cases.
An Acoustic Doppler Velocimeter (ADV) was used to take measurements across the path of the jets and monitored the velocity and the turbulent kinetic energy. After observing the velocity profiles, …

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Multiple Radar Data Merging In Hydro-Nexrad, Witold F. Krajewski, Bong Chul Seo, Anton Kruger, Piotr Domaszczynski, Gabriele Villarini, James A. Smith Dec 2008

Multiple Radar Data Merging In Hydro-Nexrad, Witold F. Krajewski, Bong Chul Seo, Anton Kruger, Piotr Domaszczynski, Gabriele Villarini, James A. Smith

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The Hydro-NEXRAD merging algorithms include two options: (1) data-based merging; and (2) product-based merging. Data-based merging algorithm takes volume scan reflectivity data from all radars involved through preprocessing algorithm that performs volume data quality control, interpolates data to synchronize temporal scale between individual radars, and finally combines data onto a common geographic grid. Reflectivity values for a given location are assigned by a weighting function with respect to the distance from the radar. This single reflectivity field is then converted to rainfall amounts using a user-requested standard approach. In product-based merging algorithm reflectivity data from multiple radars are all converted …

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Bioflocculation For Control Of Wastewater Pond Microalgae, Daniel Thomas Frost Dec 2008

Bioflocculation For Control Of Wastewater Pond Microalgae, Daniel Thomas Frost

Master's Theses

Investigates several hypotheses regarding the use of bioflocculation as a harvesting method for wastewater pond microalgae. Research performed on pilot-scale high rate ponds (HRPs) on the California Central Coast.

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Piles Under Earthquake Loads, Shamsher Prakash, Vijay K. Puri Dec 2008

Piles Under Earthquake Loads, Shamsher Prakash, Vijay K. Puri

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Piles are preferred type of foundation for supporting structures in seismic areas. their performance is affected by soil, pile and earthquake related parameters. in non-liquefying soils, the shear modulus may degrade, and material damping may increase with increasing strain/displacement. in liquefying soils, the lateral ground displacement may lead to increased lateral loads and moments on the pile leading to pile failure in bending. the loss of lateral support can also lead to buckling type failure. These issues for pile design in seismic areas are examined. © 2008 ASCE.

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The North American Transportation Security Center, Steven Douglas Kreis, Michael M. Barclay Dec 2008

The North American Transportation Security Center, Steven Douglas Kreis, Michael M. Barclay

Kentucky Transportation Center Research Report

No abstract provided.

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Fatigue Risks In The Connections Of Sign Support Structures: Phase 1, Christopher Foley, Baolin Wan, Mathew Weglarz, Matthew Hellenthal, Jordan Komp, Andrew Smith, Joseph Schmidt Dec 2008

Fatigue Risks In The Connections Of Sign Support Structures: Phase 1, Christopher Foley, Baolin Wan, Mathew Weglarz, Matthew Hellenthal, Jordan Komp, Andrew Smith, Joseph Schmidt

Transportation Reports with the Wisconsin Department of Transportation

Wisconsin sought to assess the risk of fatigue-induced fracture in its existing sign support structures designed before the latest AASHTO specifications that included fatigue design. A framework for assessing fatigue-induced fracture risk is developed and detailed synthesis of fatigue testing of connections is conducted. Statistical analysis of tests conducted since 1970 is made and models for characterizing uncertainty in the fatigue life of these connections are proposed. Recommendations regarding further fatigue testing (specimen configuration, number and stress range) are given. Statistical models for wind speed and direction are developed using historical records obtained through the National Climatic Data Center for …

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Green Roofs For A Green Town: Possibilities Of Green Roof Implementation In The Town Of Normal, Lindsey Sihau, '09 Dec 2008

Green Roofs For A Green Town: Possibilities Of Green Roof Implementation In The Town Of Normal, Lindsey Sihau, '09

Outstanding Senior Seminar Papers

Green roofs have been growing in popularity throughout the world. Scientists have been studying them since the 1980’s. This research project reviews the literature regarding both the benefits and barriers to green roof construction and management. Policies around the nation are then examined and analyzed. Suggestions are made regarding possible additions to the local Stormwater Management Policy that would emphasize the importance of sustainable building techniques such as green roofs, and hopefully offer incentive to their implementation.

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