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Full-Text Articles in Engineering

On The Computational Efficiency Of Les And Hybrid Rans-Les Models In Building Aerodynamics, Faiaz Khaled, Aly Mousaad Aly May 2021

On The Computational Efficiency Of Les And Hybrid Rans-Les Models In Building Aerodynamics, Faiaz Khaled, Aly Mousaad Aly

Faculty Publications

No abstract provided.


Weather-Related Construction Delays In A Changing Climate: A Systematic State-Of-The-Art Review, Steven J. Schuldt, Matthew R. Nicholson, Yaquarri A. Adams Ii, Justin D. Delorit Mar 2021

Weather-Related Construction Delays In A Changing Climate: A Systematic State-Of-The-Art Review, Steven J. Schuldt, Matthew R. Nicholson, Yaquarri A. Adams Ii, Justin D. Delorit

Faculty Publications

Adverse weather delays forty-five percent of construction projects worldwide, costing project owners and contractors billions of dollars in additional expenses and lost revenue each year. Additionally, changes in climate are expected to increase the frequency and intensity of weather conditions that cause these construction delays. Researchers have investigated the effect of weather on several aspects of construction. Still, no previous study comprehensively (1) identifies and quantifies the risks weather imposes on construction projects, (2) categorizes modeling and simulation approaches developed, and (3) summarizes mitigation strategies and adaptation techniques to provide best management practices for the construction industry. This paper accomplishes …


Accelerated Controller Tuning For Wind Turbines Under Multiple Hazards, Aly Mousaad Aly, Milad Rezaee Mar 2021

Accelerated Controller Tuning For Wind Turbines Under Multiple Hazards, Aly Mousaad Aly, Milad Rezaee

Faculty Publications

During their lifecycle, wind turbines can be subjected to multiple hazard loads, such as high-intensity wind, earthquake, wave, and mechanical unbalance. Excessive vibrations, due to these loads, can have detrimental effects on energy production, structural lifecycle, and the initial cost of wind turbines. Vibration control by various means, such as passive, active, and semi-active control systems provide crucial solutions to these issues. We developed a novel control theory that enables semi-active controller tuning under the complex structural behavior and inherent system nonlinearity. The proposed theory enables the evaluation of semi-active controllers’ performance of multi-degrees-of-freedom systems, without the need for time-consuming …


A Life Cycle Comparison Of Remote, Deployed Expeditionary Waste Management Scenarios, David J. Chester [*], Chandrani Mukherjee, Jeremy M. Slagley, Eric Mbonimpa, Thomas Hornstein Feb 2021

A Life Cycle Comparison Of Remote, Deployed Expeditionary Waste Management Scenarios, David J. Chester [*], Chandrani Mukherjee, Jeremy M. Slagley, Eric Mbonimpa, Thomas Hornstein

Faculty Publications

The current barrier to acquisition and utilization of viable waste-to-energy (WTE) technologies at remote or deployed expeditionary sites requires high capital and operation & maintenance costs. The impacts to environment and human health of differing expeditionary waste management strategies were compared using the Life Cycle Assessment software SimaPro 8.0. Emissions of individual waste management scenarios were compiled from peer-reviewed literature, converted to values compatible with SimaPro’s waste scenario inputs, and the calculated impacts compared using SimaPro’s pre-loaded methodologies. These calculated impacts and the economic impacts confirm that open-air burning of waste is not only dangerous to humans and the environment, …


Workshop Outcomes Report: 1st International Workshop On Seismic Resilience Of Arctic Infrastructure And Social Systems, Majid Ghayoomi, Katharine Duderstadt, Alexander Kholodov, Alexander Shiklomanov, Matthew Turner, Elham Ajorlou Jan 2021

Workshop Outcomes Report: 1st International Workshop On Seismic Resilience Of Arctic Infrastructure And Social Systems, Majid Ghayoomi, Katharine Duderstadt, Alexander Kholodov, Alexander Shiklomanov, Matthew Turner, Elham Ajorlou

Faculty Publications

No abstract provided.


Effective Early Treatment Of Microcystis Exponential Growth And Microcystin Production With Hydrogen Peroxide And Hydroxyapatite, Ian Struewing, Nathan Sienkiewicz, Chiqian Zhang, Nicholas Dugan, Jingrang Lu Dec 2020

Effective Early Treatment Of Microcystis Exponential Growth And Microcystin Production With Hydrogen Peroxide And Hydroxyapatite, Ian Struewing, Nathan Sienkiewicz, Chiqian Zhang, Nicholas Dugan, Jingrang Lu

Faculty Publications

: Mitigating cyanotoxin production is essential to protecting aquatic ecosystems and public health. However, current harmful cyanobacterial bloom (HCB) control strategies have significant shortcomings. Because predicting HCBs is difficult, current HCB control strategies are employed when heavy HCBs have already occurred. Our pilot study developed an effective HCB prediction approach that is employed before exponential cyanobacterial growth and massive cyanotoxin pro‐ duction can occur. We used a quantitative polymerase chain reaction (qPCR) assay targeting the toxin‐encoding gene mcyA to signal the timing of treatment. When control measures were applied at an early growth stage or one week before the exponential …


Improving Tolerance Control On Modular Construction Project With 3d Laser Scanning And Bim: A Case Study Of Removable Floodwall Project, Huimin Li, Chengyi Zhang, Siyuan Song, Sevilay Demirkesen, Ruidong Chang Dec 2020

Improving Tolerance Control On Modular Construction Project With 3d Laser Scanning And Bim: A Case Study Of Removable Floodwall Project, Huimin Li, Chengyi Zhang, Siyuan Song, Sevilay Demirkesen, Ruidong Chang

Faculty Publications

Quality control is essential to a successful modular construction project and should be enhanced throughout the project from design to construction and installation. The current methods for analyzing the assembly quality of a removable floodwall heavily rely on manual inspection and contact-type measurements, which are time-consuming and costly. This study presents a systematic and practical approach to improve quality control of the prefabricated modular construction projects by integrating building information modeling (BIM) with three-dimensional (3D) laser scanning technology. The study starts with a thorough literature review of current quality control methods in modular construction. Firstly, the critical quality control procedure …


United States Department Of Defense (Dod) Real Property Repair, Alterations, Maintenance, And Construction Project Contract Data: 2009–2020, Tyler Stout, Adam Teston, Brent T. Langhals, Justin D. Delorit, Carlton Hendrix, Steven J. Schuldt Oct 2020

United States Department Of Defense (Dod) Real Property Repair, Alterations, Maintenance, And Construction Project Contract Data: 2009–2020, Tyler Stout, Adam Teston, Brent T. Langhals, Justin D. Delorit, Carlton Hendrix, Steven J. Schuldt

Faculty Publications

Nearly one-half of all construction projects exceed planned costs and schedule, globally [1]. Owners and construction managers can analyze historical project performance data to inform cost and schedule overrun risk-reduction strategies. Though, the majority of open-source project datasets are limited by the number of projects, data dimensionality, and location. A significant global customer of the construction industry, the Department of Defense (DoD) maintains a vast database of historical project data that can be used to determine the sources and magnitude of construction schedule and cost overruns for many continental and international locations. The selection of data provided by the authors …


Multihazard Hurricane Fragility Model For Wood Structure Homes Considering Hazard Parameters And Building Attributes Interaction, Carol C. Massarra, Carol J. Friedland, Brian D. Marx, J. Casey Dietrich Sep 2020

Multihazard Hurricane Fragility Model For Wood Structure Homes Considering Hazard Parameters And Building Attributes Interaction, Carol C. Massarra, Carol J. Friedland, Brian D. Marx, J. Casey Dietrich

Faculty Publications

Predicting building damage as a function of hurricane hazards, building attributes, and the interaction between hazard and building attributes is a key to understanding how significant interaction reflects variation hazard intensity effect on damage based on building attribute levels. This paper develops multihazard hurricane fragility models for wood structure homes considering interaction between hazard and building attributes. Fragility models are developed for ordered categorical damage states (DS) and binary collapse/no collapse. Exterior physical damage and building attributes from rapid assessment in coastal Mississippi following Hurricane Katrina (2005), high-resolution numerical hindcast hazard intensities from the Simulating WAves Nearshore and ADvanced CIRCulation …


Conceptual Study Of A Real-Time Hybrid Simulation Framework For Monopile Offshore Wind Turbines Under Wind And Wave Loads, Wei Song, Chao Sun, Yanhui Zuo, Vahid Jahangiri, Yan Lu, Qinghua Han Aug 2020

Conceptual Study Of A Real-Time Hybrid Simulation Framework For Monopile Offshore Wind Turbines Under Wind And Wave Loads, Wei Song, Chao Sun, Yanhui Zuo, Vahid Jahangiri, Yan Lu, Qinghua Han

Faculty Publications

As an attractive renewable energy source, offshore wind plants are becoming increasingly popular for energy production. However, the performance assessment of offshore wind turbine (OWT) structure is a challenging task due to the combined wind-wave loading and difficulties in reproducing such loading conditions in laboratory. Real-time hybrid simulation (RTHS), combining physical testing and numerical simulation in real-time, offers a new venue to study the structural behavior of OWTs. It overcomes the scaling incompatibilities in OWT scaled model testing by replacing the rotor components with an actuation system, driven by an aerodynamic simulation tool running in real-time. In this study, a …


Data Quality And Reliability Assessment Of Wearable Emg And Imu Sensor For Construction Activity Recognition, Srikanth Sagar Bangaru, Chao Wang, Fereydoun Aghazadeh Aug 2020

Data Quality And Reliability Assessment Of Wearable Emg And Imu Sensor For Construction Activity Recognition, Srikanth Sagar Bangaru, Chao Wang, Fereydoun Aghazadeh

Faculty Publications

The workforce shortage is one of the significant problems in the construction industry. To overcome the challenges due to workforce shortage, various researchers have proposed wearable sensor-based systems in the area of construction safety and health. Although sensors provide rich and detailed information, not all sensors can be used for construction applications. This study evaluates the data quality and reliability of forearm electromyography (EMG) and inertial measurement unit (IMU) of armband sensors for construction activity classification. To achieve the proposed objective, the forearm EMG and IMU data collected from eight participants while performing construction activities such as screwing, wrenching, lifting, …


Groundwater Level Mapping Tool: An Open Source Web Application For Assessing Groundwater Sustainability, Steven W. Evans, Norman L. Jones, Gustavious P. Williams, Daniel P. Ames, E. James Nelson Jul 2020

Groundwater Level Mapping Tool: An Open Source Web Application For Assessing Groundwater Sustainability, Steven W. Evans, Norman L. Jones, Gustavious P. Williams, Daniel P. Ames, E. James Nelson

Faculty Publications

Decision makers need an accurate understanding of aquifer storage trends to effectively manage groundwater resources. Groundwater is difficult to monitor and quantify since the data collected from monitoring wells are often available only at irregular and infrequent intervals. We present an open-source web application (app) to visualize groundwater data over time and automatically calculate changes in aquifer storage volume to help managers assess aquifer sustainability. This app uses a novel multi-linear regression (MLR) algorithm to impute missing data for infrequently sampled wells, using correlated data from other wells in the same aquifer. The app uses this MLR-imputed data to spatially …


Exploiting Earth Observation Data To Impute Groundwater Level Measurements With An Extreme Learning Machine, Steven Evans, Gustavious P. Williams, Norman L. Jones, Daniel P. Ames, E. James Nelson Jun 2020

Exploiting Earth Observation Data To Impute Groundwater Level Measurements With An Extreme Learning Machine, Steven Evans, Gustavious P. Williams, Norman L. Jones, Daniel P. Ames, E. James Nelson

Faculty Publications

Groundwater resources are expensive to develop and use; they are difficult to monitor and data collected from monitoring wells are often sporadic, often only available at irregular, infrequent, or brief intervals. Groundwater managers require an accurate understanding of historic groundwater storage trends to effectively manage groundwater resources, however, most if not all well records contain periods of missing data. To understand long-term trends, these missing data need to be imputed before trend analysis. We present a method to impute missing data at single wells, by exploiting data generated from Earth observations that are available globally. We use two soil moisture …


Analysis Of Military Construction Cost Growth In Usaf Major Defense Acquisition Programs, Emily E. Angell, Edward D. White, Jonathan D. Ritschel, Alfred E. Thal Jr. Apr 2020

Analysis Of Military Construction Cost Growth In Usaf Major Defense Acquisition Programs, Emily E. Angell, Edward D. White, Jonathan D. Ritschel, Alfred E. Thal Jr.

Faculty Publications

This study uses descriptive and inferential statistics to identify cost growth Analysis of Military Construction of military construction (MILCON) at the programmatic level, while bridging the gap between Selected Acquisition Report (SAR) estimates and actual project costs. Findings of this study aid the cost community with appropriate allocation of resources in developing these estimates. Overall, Major Defense Acquisition Programs (MDAP) appear to experience more negative growth (cost savings) in MILCON estimates on reviewed SARs— typically less than 0.2% of the total program cost. SAR estimates became more accurate from the first to last SAR in comparison to the total MILCON …


The Viability And Simplicity Of 3d-Printed Construction: A Military Case Study, Jeneé A. Jagoda, Brandy Diggs-Mcgee, Megan Kreiger, Steven J. Schuldt Apr 2020

The Viability And Simplicity Of 3d-Printed Construction: A Military Case Study, Jeneé A. Jagoda, Brandy Diggs-Mcgee, Megan Kreiger, Steven J. Schuldt

Faculty Publications

In November 2019, U.S. Marines, Air Force, and Army Corps of Engineers personnel demonstrated the viability and simplicity of three-dimensionally (3D)-printed construction in a controlled environment at the U.S. Army Engineer Research and Development Center—Construction Engineering Research Laboratory in Champaign, Illinois. The tri-service exercise spanned three days and culminated in the construction of three 1 m × 1 m × 1 m (3 ft × 3 ft × 3 ft) concrete dragon’s teeth (square pyramid military fortifications used to defend against tanks and armored vehicles) and several custom-designed objects. The structural components were printed using a custom-built, gantry-style printer called …


Over Height Impact Avoidance And Incident Detection System, Suvash Chapain, Aly Mousaad Aly Mar 2020

Over Height Impact Avoidance And Incident Detection System, Suvash Chapain, Aly Mousaad Aly

Faculty Publications

During the construction and repair of bridges, work platforms or construction-related containment may result in restricted vertical clearances at a work location. Some tractor-trailer combinations are prone to over-height collisions at these locations. Collisions are a hazard to all drivers, and repair of the damage typically causes traffic delays. Appropriate solutions to this problem will focus on the prevention of collisions by detecting over-height vehicles and directing the drivers to take an alternate safe route. This presentation addresses the design and functionality of smart detection/alert systems that can be set up well in advance of a known vertical clearance restriction …


Wireless Underground Communications In Sewer And Stormwater Overflow Monitoring: Radio Waves Through Soil And Asphalt Medium, Usman Raza, Abdul Salam Feb 2020

Wireless Underground Communications In Sewer And Stormwater Overflow Monitoring: Radio Waves Through Soil And Asphalt Medium, Usman Raza, Abdul Salam

Faculty Publications

Storm drains and sanitary sewers are prone to backups and overflows due to extra amount wastewater entering the pipes. To prevent that, it is imperative to efficiently monitor the urban underground infrastructure. The combination of sensors system and wireless underground communication system can be used to realize urban underground IoT applications, e.g., storm water and wastewater overflow monitoring systems. The aim of this article is to establish a feasibility of the use of wireless underground communications techniques, and wave propagation through the subsurface soil and asphalt layers, in an underground pavement system for storm water and sewer overflow monitoring application. …


Improving Construction Work Zone Safety Using Technology: A Systematic Review Of Applicable Technologies, Chukwuma Nnaji, John Gambatese, Hyun Woo Lee, Fan Zhang Feb 2020

Improving Construction Work Zone Safety Using Technology: A Systematic Review Of Applicable Technologies, Chukwuma Nnaji, John Gambatese, Hyun Woo Lee, Fan Zhang

Faculty Publications

© 2019 The Authors Once considered conventional, the construction industry is gradually increasing its reliance on innovations such as the application of technologies in safety management. Given the growing literature on technology applications in safety management and the varying opinions on the utility of applied technologies, a systematic review that streamlines findings from past studies is indispensable to construction stakeholders. Although a number of review studies are available in the building construction sector, the level of fragmentation and uniqueness within the construction industry necessitates a review study specifically targeting the heavy civil sector. In response, the present study applies a …


Peak Pressures On Low Rise Buildings: Cfd With Les Versus Full Scale And Wind Tunnel Measurements, Aly Mousaad Aly, Hamzeh Gol-Zaroudi Jan 2020

Peak Pressures On Low Rise Buildings: Cfd With Les Versus Full Scale And Wind Tunnel Measurements, Aly Mousaad Aly, Hamzeh Gol-Zaroudi

Faculty Publications

This paper focuses on the processes of wind flow in the atmospheric boundary layer, to produce realistic full-scale pressures for the design of low-rise buildings. CFD with LES turbulence closure is implemented on a scale 1:1 prototype building. A proximity study was executed computationally in CFD with LES that suggests new recommendations on the computational domain size, in front of a building model, apart from common RANS-based guidelines (e.g. COST and AIJ). Our findings suggest a location of the test building, different from existing guidelines, and the inflow boundary proximity influences pressure correlation and reproduction of peak loads. The CFD …


Internet Of Things For Sustainable Mining, Abdul Salam Jan 2020

Internet Of Things For Sustainable Mining, Abdul Salam

Faculty Publications

The sustainable mining Internet of Things deals with the applications of IoT technology to the coupled needs of sustainable recovery of metals and a healthy environment for a thriving planet. In this chapter, the IoT architecture and technology is presented to support development of a digital mining platform emphasizing the exploration of rock–fluid–environment interactions to develop extraction methods with maximum economic benefit, while maintaining and preserving both water quantity and quality, soil, and, ultimately, human health. New perspectives are provided for IoT applications in developing new mineral resources, improved management of tailings, monitoring and mitigating contamination from mining. Moreover, tools …


Hydrologic Modeling As A Service (Hmaas): A New Approach To Address Hydroinformatic Challenges In Developing Countries, Michael A. Souffront Alcantara, E. James Nelson, Kiran Shakya, Christopher Edwards, Wade Roberts, Corey Krewson, Daniel P. Ames, Norman L. Jones, Angelica Gutierrez Oct 2019

Hydrologic Modeling As A Service (Hmaas): A New Approach To Address Hydroinformatic Challenges In Developing Countries, Michael A. Souffront Alcantara, E. James Nelson, Kiran Shakya, Christopher Edwards, Wade Roberts, Corey Krewson, Daniel P. Ames, Norman L. Jones, Angelica Gutierrez

Faculty Publications

Hydrologic modeling can be used to aid in decision-making at the local scale. Developed countries usually have their own hydrologic models; however, developing countries often have limited hydrologic modeling capabilities due to factors such as the maintenance, computational costs, and technical capacity needed to run models. A global streamflow prediction system (GSPS) would help decrease vulnerabilities in developing countries and fill gaps in areas where no local models exist by providing extensive results that can be filtered for specific locations. However, large-scale forecasting systems come with their own challenges. These New hydroinformatic challenges can prevent these models from reaching their …


An Open-Source Tool To Facilitate The Processing Of Grace Observations And Gldas Outputs: An Evaluation In Bangladesh, Adam J. Purdy, Cédric H. David, Md. Safat Sikder, John T. Reager, Hrishikesh A. Chandanpukar, Norman L. Jones, Mir A. Matin Oct 2019

An Open-Source Tool To Facilitate The Processing Of Grace Observations And Gldas Outputs: An Evaluation In Bangladesh, Adam J. Purdy, Cédric H. David, Md. Safat Sikder, John T. Reager, Hrishikesh A. Chandanpukar, Norman L. Jones, Mir A. Matin

Faculty Publications

Bangladesh lies at the intersection of the Ganges, Brahmaputra, and Meghna rivers with a combined average discharge of 38,000 m3s−1 ranking fourth globally. Despite the volume of water flowing through and seasonally inundating parts of the landscape, groundwater reliance is necessary to support an intensive agricultural industry. Here we use newly-developed open-source software to combine observations from the Gravity Recovery and Climate Experiment (GRACE) satellites with hydrologic estimates of land water storage from the Global Land Assimilation Data System (GLDAS) to isolate basin-scale groundwater anomalies in Northwest Bangladesh from 2002 to 2016. We place our estimates in the context of …


Enabling Stakeholder Decision-Making With Earth Observation And Modeling Data Using Tethys Platform, E. James Nelson, Sarva T. Pulla, Mir A. Matin, Kiran Shakya, Norm Jones, Daniel P. Ames, W. Lee Ellenburg, Kel N. Markert, Cédric H. David, Benjamin F. Zaitchik, Patrick Gatlin, Riley Hales Oct 2019

Enabling Stakeholder Decision-Making With Earth Observation And Modeling Data Using Tethys Platform, E. James Nelson, Sarva T. Pulla, Mir A. Matin, Kiran Shakya, Norm Jones, Daniel P. Ames, W. Lee Ellenburg, Kel N. Markert, Cédric H. David, Benjamin F. Zaitchik, Patrick Gatlin, Riley Hales

Faculty Publications

Tethys Platform is an open source framework for developing web-based applications for Earth Observation data. Our experience shows that Tethys significantly lowers the barrier for cloud-based app development, simplifies the process of accessing scalable distributed cloud computing resources and leverages additional software for data and computationally intensive modeling. The Tethys software development kit allows users to create web apps for visualizing, analyzing, and modeling Earth Observation data. Tethys platform provides a collaborative environment for scientists to develop and deploy several Earth Observation web applications across multiple Tethys portals. We work in partnership with leading regional organizations world-wide to help developing …


Preparation Of Activated Biochar-Supported Magnetite Composite For Adsorption Of Polychlorinated Phenols From Aqueous Solutions, Byung-Moon Jun, Yejin Kim, Jonghun Han, Yeomin Yoon, Chang Min Park Sep 2019

Preparation Of Activated Biochar-Supported Magnetite Composite For Adsorption Of Polychlorinated Phenols From Aqueous Solutions, Byung-Moon Jun, Yejin Kim, Jonghun Han, Yeomin Yoon, Chang Min Park

Faculty Publications

For this study, we applied activated biochar (AB) and its composition with magnetite (AB-Fe3O4) as adsorbents for the removal of polychlorophenols in model wastewater. We comprehensively characterized these adsorbents and performed adsorption tests under several experimental parameters. Using FTIR, we confirmed successful synthesis of AB-Fe3O4 composite through cetrimonium bromide surfactant. We conducted adsorption tests using AB and AB-Fe3O4 to treat model wastewater containing polychlorophenols, such as 2,3,4,6-Tetrachlorophenol (TeCP), 2,4,6-Trichlorophenol (TCP), and 2,4-Dichlorophenol (DCP). Results of the isotherm and the kinetic experiments were well adapted to Freundlich’s isotherm model and the …


Generalized Beam–Spring Model For Predicting Elastic Behavior Of Partially Composite Concrete Sandwich Wall Panels, Salam Al-Rubaye, Taylor Sorensen, Robert J. Thomas, Marc Maguire Aug 2019

Generalized Beam–Spring Model For Predicting Elastic Behavior Of Partially Composite Concrete Sandwich Wall Panels, Salam Al-Rubaye, Taylor Sorensen, Robert J. Thomas, Marc Maguire

Faculty Publications

Partially composite sandwich wall panels (SWP) have been used in the construction industry for at least twenty years. Currently there is limited codified guidance for designers of partially composite concrete SWP, but they are being designed safely and routinely. Design is often guided by the composite connector manufacturers who sell proprietary composite connectors often using a variation of truss-type matrix methods for prediction of elastic behavior of SWPs. The purpose of this paper is to quantify the accuracy of such a model in a uniform manner by developing a generalized version of these matrix models called the beam-spring model (BSM). …


Post-Treatment Of Nanofiltration Polyamide Membrane Through Alkali-Catalyzed Hydrolysis To Treat Dyes In Model Wastewater, Byung-Moon Jun, Yeomin Yoon, Chang Min Park Aug 2019

Post-Treatment Of Nanofiltration Polyamide Membrane Through Alkali-Catalyzed Hydrolysis To Treat Dyes In Model Wastewater, Byung-Moon Jun, Yeomin Yoon, Chang Min Park

Faculty Publications

This research focused on the influence of post-treatment using alkali-catalyzed hydrolysis with a full-aromatic nanofiltration (NF) polyamide membrane and its application to the efficient removal of selected dyes. The post-treated membranes were characterized through Fourier transform infrared spectroscopy, goniometry, and zeta-potential analysis to analyze the treatment-induced changes in the intrinsic properties of the membrane. Furthermore, the changes in permeability induced by the post-treatment were evaluated via the measurement of water flux, NaCl rejection, and molecular weight cutoff (MWCO) under different pH conditions and post-treatment times. Major changes induced by the post-treatment in terms of physicochemical properties were the enhancement of …


Hydrodynamic Modeling Coupled With Long-Term Field Data Provide Evidence For Suppression Of Phytoplankton By Invasive Clams And Freshwater Exports In The San Francisco Estuary, Bruce G. Hammock Jun 2019

Hydrodynamic Modeling Coupled With Long-Term Field Data Provide Evidence For Suppression Of Phytoplankton By Invasive Clams And Freshwater Exports In The San Francisco Estuary, Bruce G. Hammock

Faculty Publications

The San Francisco Estuary (California, USA) had abundant pelagic fish in the late 1960s, but has few pelagic fish today. A primary cause for this decline in fish is thought to be a trophic cascade, triggered by declining phytoplankton. Here, we describe the changes in pelagic community structure of the San Francisco Estuary. Then, we examine whether changes in hydrodynamics due to freshwater exports, which increased exponentially beginning in 1967, in addition to the 1986 invasion by the clam Potamocorbula amurensis, explain the phytoplankton loss. Hydrodynamic variables were reconstructed back to 1956 using statistical models fit to, and cross-validated against, …


Statistical Viability Analysis Of United States Air Force Estimating Cost Factor For Sustainable Construction, Philip A. Ramsey, Diedrich Prigge, Torrey J. Wagner, Alfred E. Thal Jr. May 2019

Statistical Viability Analysis Of United States Air Force Estimating Cost Factor For Sustainable Construction, Philip A. Ramsey, Diedrich Prigge, Torrey J. Wagner, Alfred E. Thal Jr.

Faculty Publications

Varying legislation and executive orders coupled with needs for energy resiliency have led the United States Air Force (USAF) to pursue sustainable construction. However, the limited understanding of initial costs to implement these changes have contributed to poor project cost estimating, resulting in 62 percent of USAF projects experiencing more than 5 percent cost growth. After reviewing 1628 USAF Military Construction (MILCON) construction projects in 922 category codes (CATCODEs), a twotailed t-test for populations with unequal variance was accomplished on the final normalized contract cost for 340 projects in 16 CATCODEs executed between 2002 and 2017. This analysis provides a …


Using Wind And Hydro Power To Sustain The Off-Grid Power Supply For A 50' Cruising Sailboat, Keisha Meyer, Torrey J. Wagner, Jada Williams May 2019

Using Wind And Hydro Power To Sustain The Off-Grid Power Supply For A 50' Cruising Sailboat, Keisha Meyer, Torrey J. Wagner, Jada Williams

Faculty Publications

Cruising sailboats operate with a power requirement modest enough to operate mostly or completely on renewable energy technology sources. Cruisers without renewable energy systems use the vessel’s diesel engine to charge the boat’s batteries; if the systems are operated at anchor, this dramatically decreases the time before the engine needs major overhaul. System users estimate a diesel engine can run approximately 8,000 hours underway before needing major overhaul, whereas operating 500 hours at anchor produces similar wear and tear on engine pistons. Although renewable energy systems have a high initial capital cost, these systems can provide the vessel’s electrical system …


Metrics For Assessing Overall Performance Of Inland Waterway Ports: A Bayesian Network Based Approach, Niamat Ullah Ibne Hossain, Farjana Nur, Raed Jaradat, Seyedmohsen Hosseini, Mohammad Marufuzzaman, Stephen M. Puryear, Randy K. Buchanan May 2019

Metrics For Assessing Overall Performance Of Inland Waterway Ports: A Bayesian Network Based Approach, Niamat Ullah Ibne Hossain, Farjana Nur, Raed Jaradat, Seyedmohsen Hosseini, Mohammad Marufuzzaman, Stephen M. Puryear, Randy K. Buchanan

Faculty Publications

Because ports are considered to be the heart of the maritime transportation system, thereby assessing port performance is necessary for a nation’s development and economic success. This study proposes a novel metric, namely, “port performance index (PPI)”, to determine the overall performance and utilization of inland waterway ports based on six criteria, port facility, port availability, port economics, port service, port connectivity, and port environment. Unlike existing literature, which mainly ranks ports based on quantitative factors, this study utilizes a Bayesian Network (BN) model that focuses on both quantitative and qualitative factors to rank a port. The …