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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Examining the effects of openings at the base of slender reinforced concrete (tilt-up) wall panels subjected to varying wind pressures

Cook, Andrew January 1900 (has links)
Master of Science / Department of Architectural Engineering and Construction Science / Kimberly Waggle Kramer / This report examines the effects of openings located at the base of reinforced concrete slender wall panels (tilt-up panels) designed in accordance with the American Concrete Institute (ACI) Committee 318-11 Building Code Requirements for Structural Concrete Section 14.8 Alternative Design of Slender Walls. The parametric study calculates the reinforcement (longitudinal) required for specific panels in accordance with ACI 318-11 Section 14.8 and compares the designs to a finite element analysis conducted with SAP 2000 version 14 to determine the appropriateness of the assumptions made in Section 14.8. Furthermore, this report compares the design of a tilt-up panel designed by Section 14.8 Alternative Design of Slender Walls and designed by Section 10.10 Slenderness Effects in Compression Members.
42

MASSPEC: multiagent system specification through policy exploration and checking

Harmon, Scott J. January 1900 (has links)
Doctor of Philosophy / Department of Computing and Information Sciences / Scott A. DeLoach / Multiagent systems have been proposed as a way to create reliable, adaptable, and efficient systems. As these systems grow in complexity, configuration, tuning, and design of these systems can become as complex as the problems they claim to solve. As researchers in multiagent systems engineering, we must create the next generation of theories and tools to help tame this growing complexity and take some of the burden off the systems engineer. In this thesis, I propose guidance policies as a way to do just that. I also give a framework for multiagent system design, using the concept of guidance policies to automatically generate a set of constraints based on a set of multiagent system models as well as provide an implementation for generating code that will conform to these constraints. Presenting a formal definition for guidance policies, I show how they can be used in a machine learning context to improve performance of a system and avoid failures. I also give a practical demonstration of converting abstract requirements to concrete system requirements (with respect to a given set of design models).
43

Analysis of a pilot-scale constructed wetland treatment system for flue gas desulfurization wastewater

Talley, Mary Katherine January 1900 (has links)
Master of Science / Department of Biological and Agricultural Engineering / Stacy L. Hutchinson / Coal-fired generation accounts for 45% of the United States electricity and generates harmful emissions, such as sulfur dioxide. With the implementation of Flue Gas Desulfurization (FGD) systems, sulfur dioxide is removed as an air pollutant and becomes a water pollutant. Basic physical/chemical wastewater treatment can be used to treat FGD wastewater, but increased regulations of effluent water quality have created a need for better, more economical wastewater treatment systems, such as constructed wetlands. At Jeffrey Energy Center, north of St. Mary’s, KS, a pilot-scale constructed wetland treatment system (CWTS) was implemented to treat FGD wastewater before releasing the effluent into the Kansas River. The objectives of this study were to 1.) determine if a portable water quality meter could be used to assess water quality and track pollutant concentrations, 2.) develop a water balance of the CTWS, 3.) generate a water use coefficient for the CWTS, and 4.) create a mass balance on the pollutants of concern. Water quality measurements were taken with a HORIBA U-50 Series Multi Water Quality Checker and compared to analytical water tests provided by Continental Analytic Services, Inc. (CAS) (Salina, KS). The water balance was created by comparing inflows and outflows of data determined through flow meters and a Vantage Pro2™ weather station. Information from the on-site weather station was also used to compute the system water use coefficient. Water sampling was conducted from date to date at 10 locations within the CWTS. In general, there was little to no relationship between the HORIBA water quality measurements and the analytical water tests. Therefore, it was recommended that JEC continue to send water samples on a regular basis to an analytical testing laboratory to assess the CWTS function and track pollutants of concern. Because the water balance was conducted during system initiation, there was a great deal of fluctuation due to problems with the pumping system, issues with the upstream FGD treatment system, extreme weather events, and immature vegetation. This fluctuation resulted in the system having a non-steady state operation, which weakened the ability to calculate a system water use coefficient. However, during periods of strong system function, the water use coefficient was similar to previous studies with maximum water use being approximately equal to the reference evapotranspiration. The results of the mass balance indicated high removals mercury, selenium, and fluoride, but low removals of boron, manganese, chloride, and sulfate were exported from the CWTS.
44

Eccentrically braced steel frames as a seismic force resisting system

Hague, Samuel Dalton January 1900 (has links)
Master of Science / Department of Architectural Engineering / Kimberly Waggle Kramer / Braced frames are a common seismic lateral force resisting system used in steel structure. Eccentrically braced frames (EBFs) are a relatively new lateral force resisting system developed to resist seismic events in a predictable manner. Properly designed and detailed EBFs behave in a ductile manner through shear or flexural yielding of a link element. The link is created through brace eccentricity with either the column centerlines or the beam midpoint. The ductile yielding produces wide, balanced hysteresis loops, indicating excellent energy dissipation, which is required for high seismic events. This report explains the underlying research of the behavior of EBFs and details the seismic specification used in design. The design process of an EBF is described in detail with design calculations for a 2- and 5-story structure. The design process is from the AISC 341-10 Seismic Provisions for Structural Steel Buildings with the gravity and lateral loads calculated according to ASCE 7-10 Minimum Design Loads for Buildings and Other Structures. Seismic loads are calculated using the Equivalent Lateral Force Procedure. The final member sizes of the 2-story EBF are compared to the results of a study by Eric Grusenmeyer (2012). The results of the parametric study are discussed in detail.
45

A bandlimited step function for use in discrete periodic extension

Pathmanathan, Sureka January 1900 (has links)
Master of Science / Department of Mathematics / Nathan Albin / A new methodology is introduced for use in discrete periodic extension of non-periodic functions. The methodology is based on a band-limited step function, and utilizes the computational efficiency of FC-Gram (Fourier Continuation based on orthonormal Gram polynomial basis on the extension stage) extension database. The discrete periodic extension is a technique for augmenting a set of uniformly-spaced samples of a smooth function with auxiliary values in an extension region. If a suitable extension is constructed, the interpolating trigonometric polynomial found via an FFT(Fast Fourier Transform) will accurately approximate the original function in its original interval. The discrete periodic extension is a key construction in the FC-Gram algorithm which is successfully implemented in several recent efficient and high-order PDEs solvers. This thesis focuses on a new flexible discrete periodic extension procedure that performs at least as well as the FC-Gram method, but with somewhat simpler implementation and significantly decreased setup time.
46

Demonstrating an approach for modeling crop growth and hydrology using SWAT 2009 in Kanopolis Lake Watershed, Kansas

Mollenkamp, Lorinda Larae January 1900 (has links)
Master of Science / Department of Biological and Agricultural Engineering / Kyle R. Douglas-Mankin / Aleksey Y. Sheshukov / According the U.S. Environmental Protection Agency’s (EPA) website, our planet is at risk of global warming due to greenhouse gas emissions. The earth’s average temperature has been reported to have risen by 1.4°F over the last century. This seemingly small increase in average planetary temperature has been linked to devastating floods, severe heat waves, and dangerous and unpredictable shifts in our climate (US EPA, 2013a). In the 2012 report, the Intergovernmental Panel on Climate Change states that bioenergy has the potential to significantly mitigate greenhouse gases as long as this is produced in a sustainable manner (Chum, et al., 2011). In light of these facts, research into the sustainable production of bioenergy sources in the United States is currently underway. To ensure that the correct biofuel crop is selected for a given region and to investigate any secondary effects of changing our nation’s agricultural practices to include biofuels, computer models can be very useful. The Soil Water Assessment Tool (SWAT) is a robust, continuous time step model that was developed by the USDA Agricultural Resource Service that can simulate changes in land use and land management and the effect this has on erosion, water quality, and other important factors. This paper describes the preliminary work to create a model of the Kanopolis Lake Watershed that is part of the Kansas River Basin using SWAT 2009. Data pertaining to weather, topography, land use, management, stream flow, and reservoirs was gathered and incorporated into the SWAT model. This was then simulated to obtain the uncalibrated data. SWAT produced unacceptable statistics for both crop yields and for stream flow using the Nash-Sutcliffe Efficiency equation and using percent bias. This suggests that the model must be calibrated to be of use in understanding both the current and future land use scenarios. Once the model is calibrated and validated, it can be used to simulate different biofuel cropping scenarios.
47

Single molecule studies of acidity in heterogeneous catalysts

Sun, Xiaojiao January 1900 (has links)
Doctor of Philosophy / Department of Chemical Engineering / Keith L. Hohn / Amorphous silica-alumina is widely used as a solid acid catalyst for various reactions in oil refining and the petrochemical industry. The strength and the number of the acid sites in the material are most often believed to arise from the alumina atoms inserted into the silica lattice. The existence of the acidity distribution across the framework is a result of the local composition or the short-range interactions on the silica-alumina surface. Conventional techniques used to characterize silica-alumina provide effective information on the average acidity, but may not reflect the heterogeneity of surface acidity within the material. Recently, it is possible to study individual catalytic sites on solid catalysts by single molecule fluorescence microscopy with high time and space resolution. Fluorophores can be chosen that emit at different wavelengths depending on the properties of the local environment. By doping these fluorophores into a solid matrix at nanomolar concentrations, individual probe molecules can be imaged. Valuable information can be extracted by analyzing changes in the fluorescence spectrum of the guest molecules within a host matrix. In this research, silica-alumina thin films were studied with single molecule fluorescence microscopy. The samples were prepared by a sol-gel method and a wide-field fluorescence microscope was used to locate and characterize the fluorescent behaviors of pH sensitive probes. In mesoporous thin films, the ratio of the dye emission at two wavelengths provides an effective means to sense the effective pH of the microenvironment in which each molecule resides. The goal of this work was to develop methods to quantify the acidity of individual micro-environments in heterogeneous networks. Pure silica films treated with external phosphate solutions of different pH values were used to provide references of the fluorescence signals from individual dye molecules. SM emission data were obtained from mesoporous Al-Si films as a function of Al content in films ranging from 0% to 20% alumina. Histograms of the emission ratio revealed that films became more acidic with increasing Al content. The acidity on interior surfaces in zeolite pores was also of interest in this work. A microfluidic device was built to isolate the interior surface from the exterior surface. Some preliminary results showed the potential of using SM fluorescence method to study the acidic properties inside the pores of zeolite crystals.
48

Fluid dynamics of cavitating sonic two-phase flow in a converging-diverging nozzle

Asher, William January 1900 (has links)
Master of Science / Department of Mechanical and Nuclear Engineering / Steven Eckels / Both cavitating and flashing flows are important phenomena in fluid flow. Cavitating flow, a common consideration in valves, orifices, and metering devices, is also a concern in loss of coolant accidents for liquid water in power plants when saturation pressures are below atmospheric pressure. Flashing flow is a common consideration for devices such as relief and expansion valves and fluid injectors as well as for loss of coolant accidents in which the coolant’s saturation pressure is above atmospheric. Of the two phenomena, flashing flow has received greater interest due to its applicability to safety concerns, though cavitating flow is perhaps of greater interest in terms of energy efficiency. It is possible for cavitating and flashing flow to actually become sonic. That is, the local velocity of a fluid can exceed the local speed of sound due to the unique properties of two-phase mixtures. When a flow becomes sonic, it is possible for the flow to accelerate and impose additional energy losses that would not otherwise occur. Models of this aspect of two-phase flow are not well developed, typically only being presented for the case of constant area ducts. In this paper two models for cavitating sonic flow are developed and described by applying the integral forms of the mass, momentum, and energy equations to a control volume of variable cross-sectional area. These models, based on the homogeneous equilibrium model (HEM) and separated flow model, are then applied to experimental data taken by the author with R-134a as the fluid of interest. Experimental data were taken with four instrumented converging-diverging nozzles of various geometries using a custom testing rig that allowed for precise control and measurement of flow parameters such as mass flow, temperature, and pressure. The resultant data from the models are then examined, focusing on the resultant velocities, Mach numbers, quality, and shear stresses.
49

Modeling power system load using intelligent methods.

He, Shengyang January 1900 (has links)
Master of Science / Department of Electrical Engineering / Shelli K. Starrett / Modern power systems are integrated, complex, dynamic systems. Due to the complexity, power system operation and control need to be analyzed using numerical simulation. The load model is one of the least known models among the many components in the power system operation. The two different load models are the static and dynamic models. The ZIP load model has been extensively studied. This has widely applied to composite load models that could maintain constant impedance, constant current, and/or constant power. In this work, various Neural Networks algorithms and fuzzy logic have been used to obtain these ZIP load model coefficients for determining the percentage of constant impedance, current, or power for the various load buses. The inputs are a combination of voltage, voltage change, and power change, or voltage and power, and the outputs consist of the ZIP load model coefficients for determining the type and the percentage of load at the bus. The trained model is used to predict the type and percentage of constant load at other buses using simulated transient data from the 16-generator system. A small study was also done using a dynamic induction machine model in addition to the ZIP load model. As expected, the results show that the dynamic model is more difficult to determine than the static model.
50

Sorption of veterinary antibiotics to woodchips

Ajmani, Manu January 1900 (has links)
Master of Science / Department of Civil Engineering / Alok Bhandari / In the upper Midwest, subsurface tile drainage water is a major contributor of nitrate (NO[subscript]3–N) coming from fertilizers and animal manure. Movement of NO[subscript]3-N through tile drainage into streams is a major concern as it can cause eutrophication and hypoxia conditions, as in the Gulf of Mexico. Denitrifying bioreactors is one of the pollution control strategies to treat contaminated tile drainage water. These bioreactors require four conditions which are: 1) organic carbon source, 2) anaerobic conditions, 3) denitrifying bacteria and 4) influent NO[subscript]3-N. This research focuses on investigating fate of veterinary antibiotics in woodchips commonly used in in-situ reactors. Tylosin (TYL) and sulfamethazine (SMZ) are two veterinary antibiotics which are most commonly used in the United States and can be found in tile water after manure is land applied. Partition coefficients of TYL and SMZ on wood were determined by sorption experiments using fresh woodchips and woodchips from an in situ reactor. It was concluded that the woodchips were an effective means to sorb the veterinary antibiotics leached into the tile water after application of animal manure. Linear partition coefficients were calculated and phase distribution relationships were established for both the chemicals. The fresh woodchips gave inconclusive data but predictions could be made by the information determined in the experiments using woodchips from a ten year old woodchip bioreactor. Desorption was also studied and the likelihood of desorption was predicted using the Apparent Hysteresis Index. Overall, it was found that the old woodchips allowed for quick sorption of both antibiotics. It was also found that SMZ had reversible sorption on old woodchips. Thus, it was concluded that the woodchip bioreactor would not be effective for removal of veterinary antibiotics from tile drainage. More research is required for the fate of TYL and to confirm the conclusion.

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