Engineering Commons^™

Yield And Crop Water Use Efficiency Response Of Drought-Tolerant And Conventional Maize Hybrids Under Different Irrigation Regimes, Plant Populations And Climate Gradients, Ali T. Mohammed

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Water scarcity in many regions of the world, including Nebraska, is imposing increasing pressure on water demands in agriculture to meet future food and fiber demand of rapidly growing world populations. One of the viable alternatives to counter this challenge is cultivating new drought-tolerant hybrids/varieties/cultivars. Recently, new drought-tolerant maize (Zea mays L.) hybrids have been developed by major seed companies. However, it is essential to evaluate the performance of these hybrids, in terms of grain yield and crop water use (actual evapotranspiration) in various climatic and soil conditions under large production settings. Research was conducted at four locations across the …

Characterization Of Stator Winding Short-Circuit Faults In Interior Permanent-Magnet Motor-Drive Systems, Andrew Strandt

Master's Theses (2009 -)

This thesis contains a comprehensive analysis of experimental data collected from a case-study interior permanent-magnet electric machine experiencing winding short-circuit faults of varying severity. The experimental data collected from the faulted machine is from both motoring operation energized by a PWM sensorless ac drive as well as generating operation driven by the test bed dynamometer with a resistive winding load. For both modes of operation a complete set of three-phase voltage and current signals was recorded and analyzed. The three fault diagnosis techniques applied and compared regarding their ability to diagnose and prognosticate a winding fault in an interior permanent-magnet …

Ion Exchange Nutrient Recovery From Municipal Wastewater, Allen Williams

Master's Theses (2009 -)

Nitrogen and phosphorus discharge is regulated due to eutrophication. Typically ammonium-nitrogen is removed through nitrification which requires energy and phosphorus (P) is removed by metal salt addition to precipitate P. A more sustainable approach may be to implement nutrient recovery to form fertilizers. Most nitrogen fertilizer is formed through the energy intensive Haber-Bosch process. Phosphate rock, a limited resource, is mined for P fertilizer. Discharge regulations and the fertilizer production costs provide an economic driver for recovery. The current project used anionic and cationic ion exchange (IX) to concentrate the nutrients with recovery by struvite precipitation. Previous work lacks direct …

Supraspinal Control Of Unilateral Locomotor Performance: An Fmri Study Using A Custom Pedaling Device, Brett Arand

Master's Theses (2009 -)

This study aimed to develop a novel unilateral pedaling device, validate its function, and use it in an fMRI study of bilateral vs. unilateral locomotor control. The new device is MRI compatible and allows for conventional coupled bilateral pedaling, along with decoupled unilateral pedaling. It was designed with an assistance mechanism to simulate the presence of the non-contributing leg while pedaling unilaterally. During coupled bilateral pedaling, the two legs work in unison: while one leg is extending in the downstroke, it provides support to lift the other leg back up as it is flexing in the upstroke. The device uses …

Quantification Of Local Hemodynamic Alterations Caused By Virtual Implantation Of Three Commercially-Available Stents For The Treatment Of Aortic Coarctation, Sung Kwon

Master's Theses (2009 -)

Patients with coarctation of the aorta (CoA) are prone to morbidity including atherosclerotic plaque that has been shown to correlate with altered wall shear stress (WSS) in the descending thoracic aorta (dAo). We created the first patient-specific computational fluid dynamics (CFD) model of a CoA patient treated by Palmaz stenting, and compared resulting WSS distributions to those from virtual implantation of the NumedCP and GenesisXD stents also commonly used for CoA. CFD models were created from magnetic resonance, fluoroscopy and blood pressure (BP) data. Simulations incorporated vessel deformation, downstream vascular resistance and compliance to match measured data and generate blood …

Numerical Simulation Model On Irreversibility Of Shock-Wave Process, Longhao Huang

Master's Theses (2009 -)

The objective of this research is to develop a better understanding of the irreversibilities associated with the shock compaction of matter, especially as a result of impact. Due to complex shock processes, experimentation alone cannot fix the material state, since properties such as internal energy, entropy as well as the shock process are not measurable. Thus, in addition to experimentation, analytical and numerical methods are also used to completely characterize the shock process, although they are restricted by underlying constitutive assumptions. Instead of using artificial irreversibility, such as artificial viscosity to simplify and stabilize the numeric shock model, this work …

Characterization Of Two-Dimensional Oculomotor Control During Goal-Directed Eye Movements In Humans, Vincent Dang

Master's Theses (2009 -)

Oculomotor control is a subset of sensorimotor control that allows humans to make extremely accurate eye movements for ADL. Impairments to oculomotor control can increase the impact of sensorimotor control deficits, especially in neurodegenerative diseases such as MS. Here, a two-dimensional computational control system of saccades and smooth-pursuit eye movements was compiled from literature to systematically characterize oculomotor control in eight visually-healthy humans as a precursor to studying the relationship between oculomotor and sensorimotor control in patient populations. Subjects visually tracked a single dot on a 41 x 30.5 cm monitor in a dark room while eye positions were recorded …

An Investigation Of Phase-Change Effects During Rapid Compression Machine Experiments, Colin Banyon

Master's Theses (2009 -)

Rapid compression machines (RCMs) are well characterized laboratory scale devices capable of achieving internal combustion (IC) engine relevant thermodynamic environments. These machines are often used to collect ignition delay times as targets for gas-phase chemical kinetic fuel autoigntion models. Modern RCMs utilize creviced piston(s) to improve charge homogeneity and allow for an adequate validation of detailed chemistry mechanisms against experiments using computationally efficient, homogeneous reactor models (HRMs). Conventionally, experiments are preformed by introducing a premixed gas of fuel + oxidizer + diluent into the machine, which is compressed volumetrically via a piston. Experiments investigating low-vapor pressure fuels (e.g. diesels, biodiesels, …

Anaerobic Co-Digestion Planning And Research For Green Bay, Wi, Jonathan Kusowski

Master's Theses (2009 -)

The aspiration to find an alternative sustainable fuel source is an ever growing concern. Anaerobic digestion might hold the answer to finding an alternative sustainable energy source. Anaerobic digestion does not only provide a renewable resource in the form of biogas, but also stabilizes wastes, preventing large amounts from being landfilled or incinerated. Anaerobic digestion of municipal wastewater sludges can often be improved by the addition of high strength industrial wastes, in a process called co-digestion. High strength industrial wastes provide an additional carbon source for the microbes to utilize and convert into usable biogas. Co-digestion also offers the opportunity …

Comparison Of Three Space Vector Pwm Methods For A Three-Level Inverter With A Permanent Magnet Machine Load, Alia Rebecca Strandt

Master's Theses (2009 -)

Much work exists on multilevel space vector pulse width modulation (PWM) to drive induction machines, in which the rotor currents are induced by stator rotating field effects. However, there are few investigations that analyze these modulation methods applied to permanent magnet (PM) and wound-field synchronous machines, in which the rotor induces a back emf in the stator. In this thesis, three different three-level space vector PWM switching sequences are applied to a three-level neutral-point-clamped (NP) inverter driving an internal permanent magnet (IPM) machine load. The inherent qualities of each of the switching sequences when under the influence of a forcing …

Developing Mhealth Solutions For Natural Family Planning, Md Miftah Uddin

Master's Theses (2009 -)

Natural Family Planning (NFP) is a method to help couples determine the fertile and infertile times of a woman’s menstrual cycle with natural indicators of fertility. NFP methods have advantages over other methods of family planning. Proper use of NFP methods also ensures high effectiveness (close to 98%) in helping couples avoid pregnancy. However, very few physicians prescribe NFP to their patients due to lack of credibility to the fertility methods and lack of access to NFP knowledge. The Marquette University College of Nursing Institute for Natural Family Planning has been researching for many years to increase knowledge and efficiency …

Automation Of Energy Demand Forecasting, Sanzad Siddique

Master's Theses (2009 -)

Automation of energy demand forecasting saves time and effort by searching automatically for an appropriate model in a candidate model space without manual intervention. This thesis introduces a search-based approach that improves the performance of the model searching process for econometrics models. Further improvements in the accuracy of the energy demand forecasting are achieved by integrating nonlinear transformations within the models. This thesis introduces machine learning techniques that are capable of modeling such nonlinearity. Algorithms for learning domain knowledge from time series data using the machine learning methods are also presented. The novel search based approach and the machine learning …

Applying An Improved Mrps-Gmm Method To Detect Temporal Patterns In Dynamic Data System, Shaobo Wang

Master's Theses (2009 -)

The purpose of this thesis is to introduce an improved approach for the temporal pattern detection, which is based on the Multivariate Reconstructed Phase Space (MRPS) and the Gaussian Mixture Model (GMM), to overcome the disadvantage caused by the diversity of shapes among different temporal patterns in multiple nonlinear time series. Moreover, this thesis presents an applicable software program developed with MATLAB for users to utilize this approach. A major study involving dynamic data systems is to understand the correspondence between events of interest and predictive temporal patterns in the output observations, which can be used to develop a mechanism …

Admittance Selection For Force Guided Assembly With Optimal Motion, Fernando Rodriguez Anton

Master's Theses (2009 -)

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Current robots lack the precise relative positioning necessary to complete automatic assembly tasks. Several solutions have been proposed. Some approaches use complex vision and force sensing systems to generate corrective motion if misalignment is present in the assembly task. Other solutions rely on generating elastic behavior, known as compliance, between the end eector and the held movable part. This compliant mechanism helps guide the movable part of the assembly into its proper position. The project focuses on designing a process by which passive compliant systems can achieve successful assembly for a range of misalignment and generate error-reducing motion that …

Parallel Implementations Of The Frank-Wolfe Algorithms For The Traffic Assignment Problem, Shawn Eugene Allen

Computational Modeling & Simulation Engineering Theses & Dissertations

Transportation planners seek to understand how to best invest limited resources for future transportation network development. The traffic assignment problem is one algorithm of great importance to planners because it provides insight into how traffic will flow within the network. The Frank-Wolfe algorithm is a traditional solution method for this optimization problem, but it has been characterized by its slow rate of convergence and poor computational performance. This thesis examines and implements several modern advancements in this algorithm which are designed to improve the rate of convergence.

In addition to algorithm changes, another method to improve the performance of an …

Using Real Property Layouts To Study The Foreclosure Contagion Effect In Real Estate With Agent-Based Modeling And Simulation, Daniele Vernon-Bido

Computational Modeling & Simulation Engineering Theses & Dissertations

Foreclosures in the United States increased sharply from 2007 to 2009. These foreclosures had a spillover effect on neighboring property values causing additional foreclosures. This is known as the foreclosure contagion effect.

Recent studies have quantified the discount attributed to foreclosure contagion using equation-based techniques. However, the discount varied between studies and markets. Further studies using agent-based modeling and simulation have demonstrated the relationship between the discounts, the time a foreclosure remains on the market, the prevailing interest rates and the average property values.

This study uses agent-based modeling and simulation (ABMS) to explore the differences that varying neighborhood densities …

Theoretical Analysis Of Torsionally Vibrating Microcantilevers For Chemical Sensor Applications In Viscous Liquids, Tao Cai

Dissertations (1934 -)

Dynamically driven microcantilevers excited in the transverse (or out-of-plane) direction are widely used as highly sensitive chemical sensing platforms in various applications. While these devices work very well in air, their performance in liquids is not efficient because of the combination of increased viscous damping and effective fluid mass. In order to improve the characteristics of microcantilevers in liquid environments, some other vibration modes such as the torsional mode and lateral (or in-plane) flexural mode have been proposed.
In this work, the characteristics of torsionally vibrating rectangular microcantilevers with length L, width b and thickness h in viscous liquids are …

Dynamic Balance Control During Treadmill Walking In Chronic Stroke Survivors, Eric Richard Walker

Dissertations (1934 -)

Maintaining dynamic balance is an important component of walking function that is likely impaired in chronic stroke survivors, evidenced by an increased prevalence of falls. Dynamic balance control requires maintaining the center of mass (COM) within the base of support during movement. During walking, dynamic balance control is achieved largely by modifying foot placement to adjust the base of support. However, chronic stroke survivors have difficulty with both precision control of foot placement, as well as reduced control of COM movement. The objective of this dissertation was to characterize dynamic balance control strategies during walking in chronic stroke survivors. Additionally, …

Theoretical Analysis Of Laterally Vibrating Hammerhead Microcantilever Sensors In A Viscous Liquid, Jinjin Zhang

Dissertations (1934 -)

Dynamically driven prismatic microcantilevers excited in the in-plane flexural mode have been investigated and used in liquid-phase sensing applications. However, the performance is restricted due to their limited surface sensing area and higher stiffness in shorter and wider prismatic microcantilevers. To increase the surface sensing area, and further improve sensing characteristics, it has been proposed to investigate symmetric hammerhead microcantilevers vibrating laterally in viscous liquid media. In this work, a theoretical model is proposed and the characteristics of the microcantilevers with symmetric shaped hammerheads (isosceles trapezoid, semi-circle, uniform rectangle and composite rectangle) are investigated. In the analysis, the stem of …

Industrial Symbiosis: Corn Ethanol Fermentation, Hydrothermal Carbonization, And Anaerobic Digestion, Patrick J. Mcnamara, Lindsey R. Jader, Frederick J. Schendel, Nicholas J. Hahn, Brandon M. Wood, Kenneth J. Valentas, Paige M. Novak, Steven J. Heilmann

Civil and Environmental Engineering Faculty Research and Publications

The production of dry-grind corn ethanol results in the generation of intermediate products, thin and whole stillage, which require energy-intensive downstream processing for conversion into commercial animal feed products. Hydrothermal carbonization of thin and whole stillage coupled with anaerobic digestion was investigated as alternative processing methods that could benefit the industry. By substantially eliminating evaporation of water, reductions in downstream energy consumption from 65% to 73% were achieved while generating hydrochar, fatty acids, treated process water, and biogas co-products providing new opportunities for the industry. Processing whole stillage in this manner produced the four co-products, eliminated centrifugation and evaporation, and …

Syllabus For Space Systems Engineering 120: Satellites And Space Systems I (Fall 2013), Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

The Fall 2013 Syllabus for Professor Bob Twiggs' Space Systems Engineering 120: Satellites and Space Systems I Course taught at Morehead State University.

Wind Power Uncertainty And Power System Performance, C. Lindsay Anderson, Judith Cardell

Engineering: Faculty Publications

The penetration of wind power into global electric power systems is steadily increasing, with the possibility of 30% to 80% of electrical energy coming from wind within the coming decades. At penetrations below 10% of electricity from wind, the impact of this variable resource on power system operations is manageable with historical operating strategies. As this penetration increases, new methods for operating the power system and electricity markets need to be developed. As part of this process, the expected impact of increased wind penetration needs to be better understood and quantified. This paper presents a comprehensive modeling framework, combining optimal …

Characterization Of The 5 Ghz Elevator Shaft Channel, Ruoyu Sun, David W. Matolak

Faculty Publications

In this paper we provide channel characterization results for the elevator shaft channel in the 5-GHz band, based upon measurements conducted in four buildings. This channel is of interest for several applications, including WiFi and public safety. Although several authors have provided elevator shaft channel characteristics for lower-frequency bands (255-MHz, 900-MHz, 1.9-GHz), to our knowledge this is the first work that addresses the 5-GHz band. Moreover, prior work has not thoroughly addressed channel characteristics when the elevator car is in motion, whereas here we provide measurement and modeling results for this dynamic condition. Our measurements were of power delay profiles, …

A New Angle On Microscopic Suspension Feeders Near Boundaries, Rachel E. Pepper, Marcus Roper, Sangjin Ryu, Nobuyoshi Matsumoto, Moeto Nagai, Howard A. Stone

Department of Mechanical and Materials Engineering: Faculty Publications

Microscopic sessile suspension feeders are a critical component in aquatic ecosystems, acting as an intermediate trophic stage between bacteria and higher eukaryotic taxa. Because they live attached to boundaries, it has long been thought that recirculation of the feeding currents produced by sessile suspension feeders inhibits their ability to access fresh fluid. However, previous models for the feeding flows of these organisms assume that they feed by pushing fluid perpendicular to surfaces they live upon, whereas we observe that sessile suspension feeders often feed at an angle to these boundaries. Using experiments and calculations, we show that living suspension feeders …

Sequential Structural And Fluid Dynamics Analysis Of Balloon-Expandable Coronary Stents., David Martin

Doctoral

As in-stent restenosis following coronary stent deployment has been strongly linked with stent-induced arterial injury and altered vessel hemodynamics, the sequential numerical analysis of the mechanical and hemodynamic impact of stent deployment within a coronary artery is likely to provide an excellent indication of coronary stent performance. Despite this observation, very few numerical studies have considered both the mechanical and hemodynamic impact of stent deployment. In light of this observation, the aim of this research is to develop a robust numerical methodology for investigating the performance of balloon-expandable coronary stents in terms of their mechanical and hemodynamic impact within a …

Impacts Of Climate Change On The Seasonality Of Low Flows In 134 Catchments In The River Rhine Basin Using An Ensemble Of Bias-Corrected Regional Climate Simulations, Mehmet C. Demirel, Martijn Booij, Arjen Hoekstra

Civil and Environmental Engineering Faculty Publications and Presentations

The impacts of climate change on the seasonality of low flows were analysed for 134 sub-catchments covering the River Rhine basin upstream of the Dutch-German border. Three seasonality indices for low flows were estimated, namely the seasonality ratio (SR), weighted mean occurrence day (WMOD) and weighted persistence (WP). These indices are related to the discharge regime, timing and variability in timing of low flow events respectively. The three indices were estimated from: (1) observed low flows; (2) simulated low flows by the semi-distributed HBV model using observed climate as input; (3) simulated low flows using simulated inputs from seven combinations …

2012 Portland Metropolitan Region Transportation System Performance Report, Robert L. Bertini, Dean George, Matthew Downey

Civil and Environmental Engineering Faculty Publications and Presentations

Our transportation system is a key ingredient in the economy, quality of life and urban fabric of the Portland metropolitan area. It has been stated in the past that it is not possible to manage our transportation system tomorrow unless we understand how it is performing today. In this spirit, Portland State University has been working with regional and statewide partners to develop new capabilities to measure, monitor and track the performance of the transportation system in real time and using archived data sources. We believe that it is possible to leverage these disparate data sources toward providing better transportation …

Decentralization Of A Multi Data Source Distributed Processing System Using A Distributed Hash Table, Grzegorz Chmaj, Shahram Latifi

Electrical & Computer Engineering Faculty Research

A distributed processing system (DPS) contains many autonomous nodes, which contribute their own computing power. DPS is considered a unified logical structure, operating in a distributed manner; the processing tasks are divided into fragments and assigned to various nodes for processing. That type of operation requires and involves a great deal of communication. We propose to use the decentralized approach, based on a distributed hash table, to reduce the communication overhead and remove the server unit, thus avoiding having a single point of failure in the system. This paper proposes a mathematical model and algorithms that are implemented in a …

The Effect Of Distribution On Product Temperature Profile In Thermally Insulated Containers For Express Shipments, Jay Singh, Sanjiv Jaggia, Koushik Saha

Industrial Technology and Packaging

An uninterrupted cold chain is a continual series of storage and distribution activities that maintain a specific temperature or temperature range. Cold chain solutions typically involve excessive packaging to ensure that the desired product temperature is maintained through the distribution process, thereby increasing the logistics-related costs. There is a myriad of solutions available for shipping temperature-sensitive products, including those constructed with a variety of packaging materials as well as refrigerants. Although static characteristics for thermally insulated packaging solutions such as the R-values of package systems as well as the melting points and heat absorption rates of various refrigerants have been …

Application Of Machine Learning And Parametric Nurbs Geometry To Mode Shape Identification, Robert Mceuen Porter

Theses and Dissertations

In any design, the dynamic characteristics of a part are dependent on its geometric and material properties. Identifying vibrational mode shapes within an iterative design process becomes difficult and time consuming due to frequently changing part definition. Although research has been done to improve the process, visual inspection of analysis results is still the current means of identifying each vibrational mode determined by a modal analysis. This research investigates the automation of the mode shape identification process through the use of parametric geometry and machine learning.In the developed method, displacement results from finite element modal analysis are used to create …