5,255 research outputs found

    Estimation of suspendent sediment concentration using acoustic methods

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    Thesis (Master)--Izmir Institute of Technology, Civil Engineering, Izmir, 2009Includes bibliographical references (leaves: 64-68)Text in English; Abstract: Turkish and Englishix, 71 leavesAcoustic Doppler current meters (ADCP, ADP, and ADV) can provide information about the suspended sediment concentration (SSC) in the water; although, they are designed for flow velocity measurements. Contrary to conventional samplers, those are labor intensive for measuring SSC, when an acoustic instrument is calibrated for a water system; no additional sensor is needed to measure SSC, enabling the researchers to measure velocity and concentration simultaneously which is required for most sediment transport studies. Recently, the acoustic instruments are investigated in different studies where signal to noise ratio (SNR) and SSC were related using different formulations. However, these studies were limited to single study site where neither the effect of particle size nor the effect of temperature was investigated. In the scope of this study, different parameters that affect the ADV.s performance prediction of SSC were investigated. In order to investigate the reliability of ADV in different environments, SSC measurements were made in different streams. Soil samples were collected from all measuring stations and particle size analysis was conducted. The multivariate data analysis was applied to the measurements to derive a relation formula between SNR and SSC. Multivariate analysis indicated that reported SSC values depended on at least three parameters; water temperature, mean diameter of the soil, and shape of the particle size distribution curve. Also, effect of high SSC conditions on ADV performance was investigated during and after rain events. Results indicated that ADV was not capable of measuring SSC when a limit concentration (SSC>400 mg/l) was exceeded

    Surrogate Accelerated Bayesian Inversion for the Determination of the Thermal Diffusivity of a Material

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    Determination of the thermal properties of a material is an important task in many scientific and engineering applications. How a material behaves when subjected to high or fluctuating temperatures can be critical to the safety and longevity of a system's essential components. The laser flash experiment is a well-established technique for indirectly measuring the thermal diffusivity, and hence the thermal conductivity, of a material. In previous works, optimization schemes have been used to find estimates of the thermal conductivity and other quantities of interest which best fit a given model to experimental data. Adopting a Bayesian approach allows for prior beliefs about uncertain model inputs to be conditioned on experimental data to determine a posterior distribution, but probing this distribution using sampling techniques such as Markov chain Monte Carlo methods can be incredibly computationally intensive. This difficulty is especially true for forward models consisting of time-dependent partial differential equations. We pose the problem of determining the thermal conductivity of a material via the laser flash experiment as a Bayesian inverse problem in which the laser intensity is also treated as uncertain. We introduce a parametric surrogate model that takes the form of a stochastic Galerkin finite element approximation, also known as a generalized polynomial chaos expansion, and show how it can be used to sample efficiently from the approximate posterior distribution. This approach gives access not only to the sought-after estimate of the thermal conductivity but also important information about its relationship to the laser intensity, and information for uncertainty quantification. We also investigate the effects of the spatial profile of the laser on the estimated posterior distribution for the thermal conductivity

    DECELERATING OPEN CHANNEL FLOW OVER GRAVEL: TURBULENCE STRUCTURE & SENSOR DEVELOPMENT

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    This dissertation describes investigations of fully turbulent decelerating hydraulically roughbed flow over gravel and the development of technology to measure turbulence and associated sediment transport in streams. Theory is developed for predicting velocity distributions in simple uniform flow using the asymptotic invariance principle and tested using laboratory and field collected data. A mixed scale is developed that accounts for bed derived turbulent structures throughout the flows depth and is used to parameterize the external boundary’s effect on the flow for the logarithmic and outer layers. The asymptotic invariance principle and similarity analysis is conducted for the equations of motion in the outer region of decelerating flow over gravel to define equilibrium conditions for this class of flows with the velocity scale is the freestream velocity. The combination of time series and time averaged statistical analysis of turbulent flow is used to elucidate the structure of flow under decelerating conditions. Time averaged statistical measures of turbulence confirm results of others for higher Froude number approaching transcritical and time series analysis shows the effects of decelerating flow on turbulence to be frequency dependent. Wireless velocity sensors were developed and found capable of measuring time averaged velocity and able to resolve macroturbulence from time series data. A semi-theoretical model of elastic deformation of cantilever beams under hydraulic forcing was coupled with circuit theory to develop a calibration procedure for the VBS that requires only three measurement points, one of which is at zero velocity. Light based sensors are developed to estimate light attenuation in water for ecological research or estimating sediment concentration in water. A semi-theoretical scaling of light attenuation and sediment properties was developed which predicts light attenuation from sediment properties. The combination of new theory on open channel velocity, turbulent structure and field sensors for measuring turbulence and sediment offers the possibility to extend our laboratory knowledge to realistic flow situations

    Poster Session

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    River Basins of Kentucky, Dan Carey, Kentucky Geological Survey An Initial Prioritization Approach for Potential Agricultural Best Management Practice Implementation Based on Subwatershed Indicators and Expert Knowledge, Brian Lee and Corey Wilson, Dept Landscape Architecture, UK Locating Karst Conduits in Cane Run Watershed of Central Kentucky Using Electrical Resistivity Methods, Junfeng Zhu and others, Kentucky Geological Survey Identification of DNA Biomarkers for Determining Sources of Fecal Pollution in Water, Rick Fowler and others, WATERS Laboratory, WKU Integrating Participatory Communication and Structured Public Involvement Processes to Better Address Superfund Issues: The Paducah Gaseous Diffusion Plant Future State Vision Project, Anna Hoover and others, KWRRI Invertebrate Production in Restored and Reference Streams, Robert Johnson and Hwa-seong Jin, Dept of Biology, UL Microscopic Population Dynamics and their Relationships to the Activated Sludge Process in a 30 MGD Wastewater Treatment Plant, Maria Lundin and David Price, LFUCG Div of Water Quality Breakpoint Analysis and Assessment of Nutrient Concentrations and Turbidity to Diatom and Macroinvertebrate Integrity in the Pennyroyal Bioregion of Kentucky, 2007-2008, Angie Crain and Brian Caskey, USGS Water Science Center Gene Expression in Zebrafish (Danio rerio) Following Exposure to Gaseous Diffusion Plant Effluent and Effluent Receiving Stream Water, Ben Brammel and Andrew Wigginton, Dept Civil Engineering, UK Restructuring the Kentucky Groundwater Data Repository Database, Bart Davidson and others, KGS Feasibility of Using 15N-Enriched E. Coli as a Bacterial Tracer in the Cane Run/Royal Spring Basin, John Warden and Alan Fryar, Dept of Earth and Environmental Sciences, UK The Use of Stable Isotope Analysis to Indentify Sources of Sediment Transported from Four Appalachian Watersheds in Southeastern Kentucky, Darren Martin and Jimmy Fox, Dept of Civil Engineering, UK Real Time Sediment Discharge Estimates Using a Turbidity and Velocity Bend Sensor Network, Robert Stewart and others, Dept of Civil Engineering, UK Estimates of Particulate Organic Carbon Flux in Various Levels of the Watershed System, William Ford and Jimmy Fox, Dept of Civil Engineering, UK Study of Performance of Velocity Bend Sensors in Flow over Gravel Bed Flumes and Rivers, Sruti Pulugurtha and others, Dept of Civil Engineering, UK Spatial Patterns of Nutrient Leaching in a Central Kentucky Pasture Undergoing Forage Renovation, Essam El-Naggar and Mark Coyne, Dept of Plant and Soil Science, UK The Effects of the Invasive Amur Honeysuckle Leaf Consumption of Green Frog Tadpoles, Andrew Wallace and Richard Durtsche, Dept of Biological Sciences, NKU Impact of the Invasive Amur Honeysuckle (Lonicera maackii) on Stand Transpiration in a Wetland Forest, Richard Boyce and S. Lincoln Fugal, Dept of Biological Sciences, NKU Relationship Between Fecal Coliform and E coli Values within the Kentucky River Basin, Madhu Akasapu and Lindell Ormsbee, KWRRI Ten Mile Creek Watershed Based Plan, Tony Powell, Northern Kentucky Health Dept and Ben Albritton, KWRRI Pathogen TMDL for South Elkhorn Watershed, Chandramouli Viswanathan, Purdue University Calumet, Ben Albritton and Lindell Ormsbee, KWRR

    Development of Landsat-based Technology for Crop Inventories: Appendices

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    There are no author-identified significant results in this report

    Development of Novel Passive Control Techniques for More Uniform Temperature at Combustor Exit and Hybrid Les/Rans Modeling

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    Gas turbines have become an important, widespread, and reliable device in the field of power generation. For any gas turbine system, the combustor is an integral part responsible for the combustion of the fuel. A number of studies have shown that the flow field exiting a combustor is highly non-uniform in pressure, velocity and, most importantly, temperature. Hot streaks amongst other non-uniformities cause varying thermal stresses on turbine blades and put pressure on the blade materials. In particular, these non-uniformities can have detrimental effects on the performance of the engine and cause a reduction in the expected life of critical components such as the turbine vanes. Due to the importance and severity of the problem, a large portion of the total combustor development effort is devoted to achieving better temperature uniformity. The present work is another attempt to develop novel passive control techniques to enhance mixing in a facility simulating the dilution zone of a typical gas turbine combustor and produce more uniform temperature at the combustor exit. Extensive experimentation was conducted to compare the proposed dilution techniques - staggered dilution holes, staggered dilution holes with streamlined body and staggered dilution holes with guide vanes at various orientations (0°, 30°, 60° and 90°). A weighted parameter was defined called `uniformity factor (\u27χ^\u27 ) to compare how close the mixture fraction is to the equilibrium value. For the majority of the flow conditions tested, the 30° guide vanes gave the most uniform temperature flow with just about 2% higher pressure loss as compared to the staggered dilution holes geometry. The fact that the use of 30° guide vanes can provide the turbine blade with 15% more uniform temperature flow than the staggered dilution holes design with merely 2% more pressure drop, has a very important implementation in order to reduce the damage of the turbine blades due to non-uniform temperature flow and extend its life-span. This would result in an overall reduction in the maintenance cost of the gas turbine systems which is quite significant. Furthermore, it was found that the introduction of the streamlined body not only improved the mixing in some cases but also helped decrease the pressure drop from inlet to exit of the experimental set-up. This is expected to increase the overall system efficiency and decrease the operating cost of a gas turbine system. Additionally, numerical modeling was used for various parametric studies to explore the effect of jet-to-mainstream momentum flux ratio on the exit temperature uniformity, variation of the cooling rate within the dilution zone, exergy analysis, etc. The other significant part of this work comprised of development of an Algebraic Stress Model (ASM) in order to estimate the turbulence via Reynolds stresses prediction. The ASM model developed is validated for a simple two-dimensional turbulent flow over a flat plate and a complex three dimensional flow around Ahmed body. The developed model is capable of predicting Reynolds stresses for a variety of flow regimes. Based on these validation it can be concluded that adopting a hybrid approach which combines the advantages of the ASM model with other turbulence models can be sought after for a more in-depth analysis of the flow structures and turbulent quantities both near-wall and away from the boundary for any fluid flow problem. The accurate prediction of the turbulent quantities plays a significant role in not just the fluid motion/transfer phenomenon rather it governs the heat exchange process as well especially in regions close to the wall

    Development of recommendations for air mixer and sampler design and combinations thereof for performance testing of HVAC equipment

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    Advances in equipment performance, and the development of variable speed equipment have led to stricter performance testing of HVAC&R equipment, requiring limited tolerances on capacity and efficiency measurements to 5% of certified ratings. This necessitates the use of third-party performance validation tests by manufacturers. Accurate airside measurement is crucial, and proper air mixing is necessary to minimize airflow nonuniformities before air sampling. However, the available literature and guidelines on air mixing and sampling device design are limited, which can result in discrepancies in measured efficiency beyond the allowable tolerances. To address this issue, this research aims to develop design recommendations for air mixing and sampling devices used in HVAC&R equipment performance testing. The study assessed the mixing effectiveness and pressure drop of three types of air mixers - baseline louvered mixer, orifice-type mixer, and orthogonal pattern louver mixer - under various operating and geometrical conditions. The results showed that all three mixing devices were capable of reducing airflow stratification. However, the orthogonal pattern louver mixer showed the most promising results due to its simple design, and the high mixing performance and low pressure drop in a limited mixing length which can be achieved due to its advantage of creating two-dimensional mixing, which is reliable even if maldistribution profile unknown, contributing to its superior performance compared to the other two mixing devices. Additionally, the investigation of design guidelines for air sampling devices for accurate and reliable performance resulted in design constraints and guidelines for sampling hole size, pitch, sampler material, and other factors. Furthermore, the study explored the effectiveness of combining air mixing and sampling devices to enhance the accuracy of capacity measurements through in-situ testing, focusing on the optimal configuration of the combination. The results suggest that selecting an air mixer with high mixing performance and a sufficient mixing length can contribute to a robust mixer-sampler combination for improved accuracy and precision of capacity and vapor mass balance measurements. Overall, this study provides valuable insights into optimal air mixing and sampling device design and configuration, enhancing bulk air condition accuracy, and improving HVAC equipment capacity measurement accuracy in psychrometric performance testing

    Improved LANDSAT to give better view of earth resources

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    The launch data of LANDSAT 3 is announced. The improved capability of the spacecrafts' remote sensors (the return beam vidicon and the multispectral scanner) and application of LANDSAT data to the study of energy supplies, food production, and global large-scale environmental monitoring are discussed along with the piggyback amateur radio communication satellite-OSCAR-D, the plasma Interaction Experiment, and the data collection system onboard LANDSAT 3. An assessment of the utility of LANDSAT multispectral data is given based on the research results to data from studies of LANDSAT 1 and 2 data. Areas studied include agriculture, rangelands, forestry, water resources, environmental and marine resources, environmental and marine resources, cartography, land use, demography, and geological surveys and mineral/petroleum exploration

    Proceedings of 2010 Kentucky Water Resources Annual Symposium

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    This conference was planned and conducted as part of the state water resources research annual program with the support and collaboration of the Department of the Interior, U.S. Geological Survey and the University of Kentucky Research Foundation, under Grant Agreement Number 06HQGR0087. The views and conclusions contained in this document and presented at the symposium are those of the abstract authors and presenters and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government or other symposium organizers and sponsors
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