Engineering Commons^™

Assessing Trichloromethane Formation And Control In Algal-Stimulated Waters Amended With Nitrogen And Phosphorus, Clinton Mash

Graduate Theses and Dissertations

Nitrogen (N) and phosphorus (P) enrichments can stimulate algal growth in drinking water sources, which can cause increased production of disinfection byproduct (DBP) precursors. However, the effect of systematic N and P enrichments on DBP formation and control has not been adequately studied. In this work, we enriched samples from a drinking water source - sampled on April 5, May 30, and August 19, 2013 - with N and P to stimulate algal growth at N:P ratios covering almost five orders of magnitude (0.2-4,429). To simulate DBP-precursor removal processes at drinking water treatment plants (DWTPs), the samples were treated with …

Assessing The Impact Of Chlorine Residual On Trihalomethane And Haloacetonitrile Formation Under Chlorination And Chloramination Disinfection Regimes, Thien Duc Do

Graduate Theses and Dissertations

A disinfection byproduct (DBP) formation potential (FP) test can be used to indirectly measure the concentration of DBP precursors in natural waters, permitting assessment of various DBP-related treatment processes and control strategies. While these tests require a 7-day chlorine residual (CR) between 3-5 mg L^-1 as Cl², it is not well known if this recommended residual corresponds to the true DBPFP (i.e., the maximum concentrations) for trihalomethanes (THMs) and haloacetonitriles (HANs). In this study, THMs and HANs were quantified as a function of CR under three common disinfection regimes: (1) free chlorine at pH 7.0 (FC7), (2) …

Manifold Learning Based Spectral Unmixing Of Hyperspectral Remote Sensing Data, Jun-Hwa Chi

Open Access Dissertations

Nonlinear mixing effects inherent in hyperspectral data are not properly represented in linear spectral unmixing models. Although direct nonlinear unmixing models provide capability to capture nonlinear phenomena, they are difficult to formulate and the results are not always generalizable. Manifold learning based spectral unmixing accommodates nonlinearity in the data in the feature extraction stage followed by linear mixing, thereby incorporating some characteristics of nonlinearity while retaining advantages of linear unmixing approaches. Since endmember selection is critical to successful spectral unmixing, it is important to select proper endmembers from the manifold space. However, excessive computational burden hinders development of manifolds for …

Adaptive Targeting: Engaging Farmers To Assess Perceptions And Improve Watershed Modeling, Optimization, And Adoption Of Agricultural Conservation Practices, Margaret Mccahon Kalcic

Open Access Dissertations

Targeting agricultural conservation practices to farmland that has the greatest impact on surface water quality has received wide support from scientists and watershed managers. The targeting approach has, however, been politically contentious as many believe farmers will oppose the approach on grounds such as privacy invasion and unfair distribution of government incentives. Targeting conservation practices using complex optimization models has become common in the scientific community, and yet targeted results are underutilized in practice because of difficulties such as knowledge transfer and absence of a political framework for their use. For targeting to be successful, it must be politically supported …

Effect Of Lightweight Aggregate Moisture Content On Internally Cured Concrete, Casey Jones

Graduate Theses and Dissertations

Putting an end to the rapid deterioration of concrete structures in the United States will only occur through the introduction of better materials and construction methods. The American Society of Civil Engineers (ASCE) reports the overall condition of concrete bridges in the United States to be a "C+". Though better than other areas of the infrastructure, there is still room for improvement in concrete bridges. One major area that may be improved is that of the concrete bridge deck. The bridge deck is comprised of the actual driving surface. It is subject to many deterioration mechanisms including freeze/thaw cycles, de-icing …

Parameterizing Analytical Models To Support An Empirically Based Warehouse Design Methodology, Lisa Thomas

Graduate Theses and Dissertations

Research in the area of warehouse design is characterized by a myriad of analytical models that address one, typically small and isolated, area of the warehouse. These models, although important in gaining insight into one question of warehouse design, are of limited value when one considers the larger question of overall warehouse design. Thus, research in the area of overall warehouse design typically consists of procedure-driven processes based on qualitative factors and not the quantifiable results of analytical models.

In contrast, practitioners have significant empirical data related to how a design alternative performs in an industry, a company, or a …

Evaluation Of Broiler Litter Heat Production During Windrowing & Nitrogen Based Gas Emission Mitigation Using Biofilter, Min Lei

Graduate Theses and Dissertations

Ammonia emission from animal feeding operations (AFOs) has negative effects on environment and animals' health. Thus measuring and mitigating ammonia emission from AFOs is important for environmental protection. In chapter I, different ammonia measurements were discussed and a mitigation technology- biofilter was represented.

In-house windrowing of built-up litter has been used by broiler producers to reduce pathogen loads and rejuvenate litter for the next flock. When litter is piled up for an extended period during downtime, heat generated by the litter pile can become a substantial heat source due to the metabolism of microorganisms. In chapter II, heat production rates …

Development Of Hydrodynamic Channel Routing Model Of The Lower Rio Grande River To Assist In Flood And Stormwater Management, Andrew W. Leeper

Theses and Dissertations - UTB/UTPA

Flooding and stormwater management of the Lower Rio Grande River (LRG) has become a major issue throughout the years with local entities along the river. The purpose of this study is to develop a hydrodynamic channel routing model to predict water surface elevation changes due to flooding. The study area consists of the LRG from Los Ebanos to Brownsville, Texas. This hydrodynamic model displays the hydraulics of the water flow through the LRG and determines where potential flood hazards exist. To verify the accuracy of the model a series of calculated output hydrographs were established at the Progreso Bridge and …

Creep, Fatigue And Creep-Fatigue Interactions In Modified 9% Cr - 1% Mo (P91) Steels, Valliappa Kalyanasundaram

Graduate Theses and Dissertations

Grade P91 steel, from the class of advanced high-chrome ferritic steels, is one of the preferred materials for many elevated temperature structural components. Creep-fatigue (C-F) interactions, along with oxidation, can accelerate the kinetics of damage accumulation and consequently reduce such components' life. Hence, reliable C-F test data is required for meticulous consideration of C-F interactions and oxidation, which in turn is vital for sound design practices. It is also imperative to develop analytical constitutive models that can simulate and predict material response under various long-term in-service conditions using experimental data from short-term laboratory experiments. Consequently, the major objectives of the …

Return To Traffic Of Full Depth Reclamation Pavements, Robert Benjamin Hill

Graduate Theses and Dissertations

Full-Depth Reclamation (FDR) is a cost-effective rehabilitation treatment for deteriorated pavements. However, when using asphalt emulsion based rehabilitation techniques one of the most challenging aspects of FDR is determining when traffic can be returned to the rehabilitated pavement surface. Since asphalt emulsion mixtures need ample time for curing, they cannot be sealed with a surface layer until the water has evaporated from the rehabilitated layer. It is often not possible to keep the road closed until all of the water has evaporated and the surface layer is placed, therefore, at some point the traffic needs to be returned to the …

Variability In The Hydraulic Conductivity Of A Test Pad Liner System Using Different Testing Techniques, Matthew Jonathan Nanak

Graduate Theses and Dissertations

Historic methods (the time lag approach, the velocity approach, and the Z-t approach), utilized to reduce two stage borehole test data, were evaluated. Two of the historic methods provided viable results and were used for this research project. Additionally, these two methods are recommended for reducing two stage borehole test data in the future.

Flexible wall permeameter and soil index laboratory testing were conducted on the soil used to construct three environmentally controlled compacted clay liners (test pads) to develop a zone of acceptance (placement window). Using the results from the laboratory testing, two acceptance criterions were evaluated, while one …

Simulating Land Use Land Cover Change Using Data Mining And Machine Learning Algorithms, Amin Tayyebi

Open Access Dissertations

The objectives of this dissertation are to: (1) review the breadth and depth of land use land cover (LUCC) issues that are being addressed by the land change science community by discussing how an existing model, Purdue's Land Transformation Model (LTM), has been used to better understand these very important issues; (2) summarize the current state-of-the-art in LUCC modeling in an attempt to provide a context for the advances in LUCC modeling presented here; (3) use a variety of statistical, data mining and machine learning algorithms to model single LUCC transitions in diverse regions of the world (e.g. United States …

An Evaluation Of Spatial Variability Of Water Stress Index Across The United States: Implications Of Supply And Demand In The East Vs The West, Jennifer Ann Roath

Open Access Theses

In order to support both human and environmental needs, high quality fresh water must be available when and where it is required. As a metric for indicating unsustainable water usage, WSI is only useful when the values reflect accurate interactions between supply and demand; however, the complexity of temporal and spatial variability of available fresh water complicates the analysis of water stress.

The overall goal of this project was to investigate the spatial variability of water stress across the United States and the appropriate spatial scale for management decisions. To accomplish this, a national dataset describing spatial distribution and breakdown …

Product Characterization And Headspace Analysis Of Solar Irradiated Aqueous C60 Clusters, Dan Su

Open Access Theses

Buckminsterfullerene (C60) is an important fullerene material that has drawn much attention and is currently being applied in many different fields. It was discovered in 1985. As its production has largely increased to meet these industrial needs, it is obvious that its environmental occurrence, especially in aqueous systems, will occur. To further provide information for environmental toxicity studies and for its risk assessment, this thesis focuses on the photo transformation processes of aqueous C60 clusters (Aqu/nC60), with a particular interest in measuring any mineralization that occurs under different irradiation conditions. Two sets of experiments were conducted to test for CO2 …

Nutrient Recovery From Anaerobically-Digested Dairy Manure By Struvite Formation And Its Effect On Gas Releases, Zhong Qiao

Open Access Theses

Manure management practices such as anaerobic digestion and lagoon storage have become important issues for large dairy farms partially due to water quality and air quality concerns caused by excess nitrogen and phosphorus. Prior research efforts have proven that struvite formation is an effective method for nutrients recovery from both municipal and agricultural wastewaters. However, little is known about nutrient recovery through struvite formation from anaerobically-digested dairy manure effluents.The effects of struvite precipitation on the releases of gases such as NH3, H2S, and CO2 are also unclear.

In this thesis, both bench-scale tests and pilot-scale storage tests were conducted to …

Interactional Analysis Of Emergent Risks In Institutionally Diverse Construction Projects, Nader Naderpajouh

Open Access Dissertations

Naderpajouh, Nader Ph.D., Purdue University, December 2013. Interactional Analysis of Emergent Risks in Institutionally Diverse Construction Projects. Major Professor: Makarand Hastak.

Construction projects, as complex systems of systems (SOS), increasingly involve institutionally diverse actors that escalate complexity of the projects. Examples of these actors include the export credit agencies, international organizations such as the World Bank, non-governmental organizations (NGO), regulatory actors, transnational organizations, as well as public and community groups. The observed surge in complexity of the projects aim to enhance their robustness in: i) sustaining the increasing demand for service of these projects, and ii) sustaining the contextual fluctuation …