Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

University of Iowa

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 1 - 30 of 1083

Full-Text Articles in Engineering

Modeling Of Conservation Practices On A Huc-12 Watershed Scale Using Hydrological Simulation Program -- Fortran, Greg Geimer Aug 2018

Modeling Of Conservation Practices On A Huc-12 Watershed Scale Using Hydrological Simulation Program -- Fortran, Greg Geimer

Theses and Dissertations

Conservation practices are frequently used to try and restore the natural resilience of the landscape to retain water, decrease nutrient loads, and mitigate flooding. Quantifying the potential benefits of conservation practices can inform stakeholders and improve the effectiveness of watershed planning. To this end, an existing Hydrological Simulation Program --- FORTRAN (HSPF) model of the English River was enhanced to enable detailed modeling of conservation practices. Using site-specific nutrient removal wetlands and water and sediment control basins (WASCOBs) derived from the Agricultural Conservation Planning Framework (ACPF) two 12-digit hydrologic unit code (HUC-12) watersheds within the English River, Headwaters North English River ...


Identification Of Potential Conservation Practices And Hydrologic Modeling Of The Upper Iowa Watershed, Trevor Julian Rundhaug Aug 2018

Identification Of Potential Conservation Practices And Hydrologic Modeling Of The Upper Iowa Watershed, Trevor Julian Rundhaug

Theses and Dissertations

In 2016 the Iowa Watershed Approach (IWA) was created to increase community resiliency against flooding, to develop hydrologic assessments that would identify strategies to reduce flooding, and to implement those strategies within nine identified watersheds that experienced flooding between 2011 and 2013. One of the nine watersheds was the Upper Iowa watershed located in northeast Iowa. This thesis focuses on the work that has been done to create a hydrologic assessment of the Upper Iowa watershed. The hydrologic assessment identifies potential conservation practices, creates a hydrologic model to assess the hydrologic cycle over the past ten years, and identifies strategies ...


Structural And Functional Assessments Of Copd Populations Via Image Registration And Unsupervised Machine Learning, Babak Haghighi Aug 2018

Structural And Functional Assessments Of Copd Populations Via Image Registration And Unsupervised Machine Learning, Babak Haghighi

Theses and Dissertations

There is notable heterogeneity in clinical presentation of patients with chronic obstructive pulmonary disease (COPD). Classification of COPD is usually based on the severity of airflow limitation (pre- and post- bronchodilator FEV1), which may not sensitively differentiate subpopulations with distinct phenotypes. A recent advance of quantitative medical imaging and data analysis techniques allows for deriving quantitative computed tomography (QCT) imaging-based metrics. These imaging-based metrics can be used to link structural and functional alterations at multiscale levels of human lung. We acquired QCT images of 800 former and current smokers from Subpopulations and Intermediate Outcomes in COPD Study (SPIROMICS). A GPU-based ...


Design For Test Methods To Reduce Test Set Size, Yingdi Liu Aug 2018

Design For Test Methods To Reduce Test Set Size, Yingdi Liu

Theses and Dissertations

With rapid development in semiconductor technology, today's large and complex integrated circuits require a large amount of test data to achieve desired test coverage. Test cost, which is proportional to the size of the test set, can be reduced by generating a small number of highly effective test patterns. Automatic Test Pattern Generators (ATPGs) generate effective deterministic test patterns for different fault models and can achieve high test coverage. To reduce ATPG-produced test set size, design for test (DFT) methods can be used to further improve the ATPG process and apply generated test patterns in more efficient ways.

The ...


An Evaluation Of An Automated, Interactive Learning Method For A Database Query Language, Summer L. Campbell Aug 2018

An Evaluation Of An Automated, Interactive Learning Method For A Database Query Language, Summer L. Campbell

Theses and Dissertations

Effective learning models adopt a highly structured approach for introductory topics, then provide students more freedom as topics increase in depth and complexity. The structure guides beginning students with rapid, appropriate feedback and provides a framework that can be expanded later with extra flexibility that encourages students to flesh out the basic framework with trial and error. This trial and error phase would also be more effective with informative feedback but providing copious feedback on open-ended problems is only feasible with a small student-to-teacher ratio or with the help of e-learning. Training engineers involves introducing many complex topics and the ...


An Investigation Of Measurement Method And Phase Change In A Latent Heat Energy Storage Device, Jared Becker Aug 2018

An Investigation Of Measurement Method And Phase Change In A Latent Heat Energy Storage Device, Jared Becker

Theses and Dissertations

Exploring uses of two-phase mixtures as a way to store peak solar energy for off-peak usage is a novel approach that has been gaining attention in recent years to address the issues tied to solid fuel dependence. This research explores a “solar salt” mixture (40%wt KNO3 and 60%wt NaNO3) in an aluminum enclosure under two test conditions: conduction enhancement and no conduction enhancement. The central aim is to develop an understanding of thermal distributions and melt developments as the system moves from room temperature to 300 oC. Thermal pattern development is explored by experimentally observing a 2-D temperature ...


A Comparison Of Linear And Nonlinear Ecg-Based Methods To Assess Pilot Workload In A Live-Flight Tactical Setting, Christopher Patrick Reichlen May 2018

A Comparison Of Linear And Nonlinear Ecg-Based Methods To Assess Pilot Workload In A Live-Flight Tactical Setting, Christopher Patrick Reichlen

Theses and Dissertations

This research compares methods for measuring pilot mental workload (MWL) from the electrocardiogram (ECG) signal. ECG-based metrics have been used extensively in MWL research. Heart rate (HR) and heart-rate variability (HRV) exhibit changes in response to varying levels of task demand. Classical methods for HRV analysis examine the ECG signal in the linear time and frequency domains. More contemporary research has advanced the notion that nonlinear elements contribute to cardiac control and ECG signal generation, spawning development of analytical techniques borrowed from the domain of nonlinear dynamics (NLD). Applications of nonlinear HRV analysis are substantial in clinical diagnosis settings; however ...


Submerged Attached-Growth Reactors As Lagoon Retrofits For Cold-Weather Ammonia Removal, Rebecca Ruth Mattson May 2018

Submerged Attached-Growth Reactors As Lagoon Retrofits For Cold-Weather Ammonia Removal, Rebecca Ruth Mattson

Theses and Dissertations

Small towns that operate wastewater treatment lagoons struggle to meet ammonia limits in cold weather. Here we report the performance of a lagoon, retrofitted with submerged attached-growth reactors (SAGRsTM), to provide insight on ammonia effluent compliance and optimal SAGR sizing as functions of water temperature. The lagoon-SAGR water resource recovery facility (WRRF) removed 95% of incoming ammonia with 94% attributable to the SAGRs. The high treatment capacity of the two primary SAGRs, evidenced by nearly continuous dissolved oxygen saturation and exceedingly high ammonia removals, suggested the two secondary SAGRs were essentially unnecessary and that all four SAGRs should be reduced ...


Differentiation Between Causes Of Optic Disc Swelling Using Retinal Layer Shape Features, John William Miller May 2018

Differentiation Between Causes Of Optic Disc Swelling Using Retinal Layer Shape Features, John William Miller

Theses and Dissertations

The optic disc is the region of the retina where the optic nerve exits the back of the eye. A number of conditions can cause the optic disc to swell. Papilledema, optic disc swelling caused by raised intracranial pressure (ICP), and nonarteritic anterior ischemic optic neuropathy (NAION), swelling caused by reduced blood flow to the back of the eye, are two such conditions. Rapid, accurate diagnosis of the cause of disc swelling is important, as with papilledema the underlying cause of raised ICP could potentially be life-threatening and may require immediate intervention.

The current clinical standard for diagnosing and assessing ...


Control Of Swelling, Electrochemical, And Elongation Properties Of Photopolymers Through The Modification Of Structure, Jacob Ryan Mclaughlin May 2018

Control Of Swelling, Electrochemical, And Elongation Properties Of Photopolymers Through The Modification Of Structure, Jacob Ryan Mclaughlin

Theses and Dissertations

Modifying photopolymer structure on the molecular and nanoscale level permits tailoring materials for use in a wide variety of applications. Understanding the fundamentals behind polymer structure at these levels permits the control of material properties. This work gains insight into the modification of structure on two levels, the nanoscale by use of structure templates and the molecular scale through the modification of polymer network formation.

Lyotropic liquid crystals (LLCs) are a type of self-assembling surfactant system, which in combination with photopolymerization can be used to template ordered nanostructure within polymer materials. This structure can be controlled and utilized to influence ...


Urban And Rural Flood Forecasting: A Case Study Of A Small Town In Iowa, Lauren Elise Grimley May 2018

Urban And Rural Flood Forecasting: A Case Study Of A Small Town In Iowa, Lauren Elise Grimley

Theses and Dissertations

Floods are the most common natural disaster in the U.S. as reported by the Federal Emergency Management Administration (FEMA), and there is a need to provide advance warning to vulnerable communities on the potential risks of flooding after intense storms. The key drivers of urban hydrological research include climate change impacts and adaption, city resilience to hydrological extremes, and integration with emergency management and city planning disciplines. Significant advances in modeling techniques and computational resources have made real-time flood forecasting tools in urban and rural areas an achievable goal, but there is no universal method for flood modeling. Urban ...


Local Properties And Rupture Characteristics Of Thoracic Aortic Aneurysm Tissue, Yuanming Luo May 2018

Local Properties And Rupture Characteristics Of Thoracic Aortic Aneurysm Tissue, Yuanming Luo

Theses and Dissertations

Ascending thoracic aortic aneurysms (ATAAs) are focal dilatations in the aorta that are prone to rupture or dissect. Currently, the clinically used indicator of the rupture risk is the diameter. However, it has been demonstrated that the diameter alone may not properly predict the risk. To evaluate the rupture risk, one must look into the local mechanical conditions at the rupture site and understand how rupture is triggered in the tissue which is a layered fibrous media. A challenge facing experimental studies of ATAA rupture is that the ATAA tissue is highly heterogeneous; experimental protocols that operate under the premise ...


Development Of Electrospun Polymer Nanofiber Mats For Removal Of Uranium From Aqueous Systems, Adam Joseph Johns May 2018

Development Of Electrospun Polymer Nanofiber Mats For Removal Of Uranium From Aqueous Systems, Adam Joseph Johns

Theses and Dissertations

Uranium contamination in drinking water sources, such as ground or surface water, poses a potential health risk. In areas, such as the Navajo Nation, uranium levels can be found at concentrations ~300 times higher than the maximum concentration limit (MCL) set by the Environmental Protection Agency (EPA) of 30 µg/L. Exposure to these contaminated waters can result in elevated uranium concentrations within the body even after several months of eliminating the source. Inside the body uranium is a nephrotoxin (damages the kidney) and has been linked to cancer among other health problems. Reducing these health risks towards individuals requires ...


Photochemical Transformations Of Dichloroacetamide Safeners, Andrew Kral May 2018

Photochemical Transformations Of Dichloroacetamide Safeners, Andrew Kral

Theses and Dissertations

Safeners are widely used ingredients in commercial herbicide formulations, but their environmental fate has garnered relatively little scrutiny because of their classification as “inert” by the US EPA. Here, we investigated the photolysis of one popular class of safeners, dichloroacetamides, to better understand their persistence and formation potential for bioactive transformation products in surface waters. Of four commonly used dichloracetamide safeners only benoxacor underwent direct photolysis. Benoxacor had a half-life of 7.7 min when irradiated at pH 7, thus photolysis will likely be an important fate pathway in surface waters. Other dichloroacetamide safeners AD-67, dichlormid, and furilazole, while resistant ...


Modeling Of Shrinkage Porosity Defect Formation During Alloy Solidification, Vahid Khalajzadeh May 2018

Modeling Of Shrinkage Porosity Defect Formation During Alloy Solidification, Vahid Khalajzadeh

Theses and Dissertations

Among all casting defects, shrinkage porosities could significantly reduce the strength of metal parts. As several critical components in aerospace and automotive industries are manufactured through casting processes, ensuring these parts are free of defects and are structurally sound is an important issue. This study investigates the formation of shrinkage-related defects in alloy solidification. To have a better understanding about the defect formation mechanisms, three sets of experimental studies were performed. In the first experiment, a real-time video radiography technique is used for the observation of pore nucleation and growth in a wedge-shaped A356 aluminum casting. An image-processing technique is ...


Trajectory-Based Methods To Predict User Churn In Online Health Communities, Apoorva Joshi May 2018

Trajectory-Based Methods To Predict User Churn In Online Health Communities, Apoorva Joshi

Theses and Dissertations

Online Health Communities (OHCs) have positively disrupted the modern global healthcare system as patients and caregivers are interacting online with similar peers to improve quality of their life. Social support is the pillar of OHCs and, hence, analyzing the different types of social support activities contributes to a better understanding and prediction of future user engagement in OHCs.

This thesis used data from a popular OHC, called Breastcancer.org, to first classify user posts in the community into the different categories of social support using Word2Vec for language processing and six different classifiers were explored, resulting in the conclusion that ...


New Bayesian Methods For Quality Control Applications, Baosheng He May 2018

New Bayesian Methods For Quality Control Applications, Baosheng He

Theses and Dissertations

In quality control applications, the most basic tasks are monitoring and fault diagnosis. Monitoring results determines if diagnosis is required, and conversely, diagnostic results aids better monitoring design. Quality monitoring and fault diagnosis are closely related but also have significant difference. Essentially. monitoring focus on online changepoint detection, whilst the primary objective of diagnosis is to identify fault root causes as an offline method. Several critical problems arise in the research of quality control: firstly, whether process monitoring is able to distinguish systematic or assignable faults and occasional deviation; secondly, how to diagnose faults with coupled root causes in complex ...


Microstructure Prediction Of Severe Plastic Deformation Manufacturing Processes For Metals, Ninggang Shen May 2018

Microstructure Prediction Of Severe Plastic Deformation Manufacturing Processes For Metals, Ninggang Shen

Theses and Dissertations

The objective of the research presented in this thesis has been to develop a physics-based dislocation density-based numerical framework to simulate microstructure evolution in severe plastic deformation (SPD) manufacturing processes for different materials. Different mechanisms of microstructure evolution in SPD manufacturing processes were investigated and summarized for different materials under dynamic or high strain rates over a wide temperature range. Thorough literature reviews were performed to clarify discrepancies of the mechanism responsible for the formation of nanocrystalline structure in the machined surface layer under both low-temperature and high-temperature conditions.

Under this framework, metallo-thermo-mechanically (MTM) coupled finite element (FE) models were ...


Mri-Based Active Shape Model Of The Human Proximal Femur Using Fiducial And Secondary Landmarks And Its Validation, Xiaoliu Zhang May 2018

Mri-Based Active Shape Model Of The Human Proximal Femur Using Fiducial And Secondary Landmarks And Its Validation, Xiaoliu Zhang

Theses and Dissertations

Osteoporosis, associated with reduced bone mineral density and structural degeneration, greatly increases the risk of fragility fracture. Magnetic resonance imaging (MRI) has been applied to central skeletal sites including the proximal femur due to its non-ionizing radiation. A major challenge of volumetric bone imaging of the hip is the selection of regions of interest (ROIs) for computation of regional bone measurements. To address this issue, an MRI-based active shape model (ASM) of the human proximal femur is applied to automatically generate ROIs. The challenge in developing the ASM for a complex three-dimensional (3-D) shape lies in determining a large number ...


Validation Of Computational Methods For Fracture Assessment Of Metastatic Disease To The Proximal Femur, Palani Taver Permeswaran May 2018

Validation Of Computational Methods For Fracture Assessment Of Metastatic Disease To The Proximal Femur, Palani Taver Permeswaran

Theses and Dissertations

Stage IV cancer is characterized by a cancer’s ability to metastasize, or spread throughout the body. Metastatic disease in bone is a devastating condition affecting hundreds of thousands of people each year. Stage IV cancer patients suffering from metastatic disease in the proximal femur are at high risk of catastrophic pathologic fracture, an event which severely impacts patient health. Although metrics have been created to assess the risk of impending fracture, they lack specificity in the proximal femoral region. Shortcomings of these metrics further complicate clinical decision making related to prophylactic fixation in these medically compromised individuals.

Fortunately, by ...


High-Fidelity Multidisciplinary Design Optimization Of A 3d Composite Material Hydrofoil, Silvia Volpi May 2018

High-Fidelity Multidisciplinary Design Optimization Of A 3d Composite Material Hydrofoil, Silvia Volpi

Theses and Dissertations

Multidisciplinary design optimization (MDO) refers to the process of designing systems characterized by the interaction of multiple interconnected disciplines. High-fidelity MDO usually requires large computational resources due to the computational cost of achieving multidisciplinary consistent solutions by coupling high-fidelity physics-based solvers. Gradient-based minimization algorithms are generally applied to find local minima, due to their efficiency in solving problems with a large number of design variables. This represents a limitation to performing global MDO and integrating black-box type analysis tools, usually not providing gradient information. The latter issues generally inhibit a wide use of MDO in complex industrial applications.

An architecture ...


Investigating The Effect Of Fluid Shear Stress On The Failure Of Cancer Cell Membranes: An Experimental And Computational Analysis, Leah M. Vandenbosch May 2018

Investigating The Effect Of Fluid Shear Stress On The Failure Of Cancer Cell Membranes: An Experimental And Computational Analysis, Leah M. Vandenbosch

Theses and Dissertations

Cancer metastasis, or the formation of a secondary tumor at a site distant from the primary tumor, is known to be an inefficient process. Historically, it was believed that the shear stresses and forces experienced by cancer cells traveling through the circulatory system are major limiting factors to their metastatic potential and viability. High levels of fluid shear stress are known to be capable of destroying tumor cells. However, more recent research has shown that cancer cells survive migration through the circulatory system and extravasation into distant tissues with a high degree of efficiency, indicating that hemodynamic forces are not ...


Neuropsychological And Morphometric Correlates Of Decision Making With The Coin Flip Task, Ashten Sherman Jan 2018

Neuropsychological And Morphometric Correlates Of Decision Making With The Coin Flip Task, Ashten Sherman

University of Iowa Honors Theses

The purpose of this study was to determine how older adults perform on a decision- making task (referred to as the Coin Flip Task), and how this performance correlates with demographic, neuropsychological, and brain morphometry variables. The study of decision making ability among older adults is important for several reasons. First, older adults frequently make “weighty” decisions as they age, such as important financial and medical decisions. When less than optimal decisions are made, it is difficult for the older adult to recover from or fix that decision given their relatively limited longevity. Second, decision making ability emanates from a ...


Multi-Parented End-Effectors In Optimization-Based Prediction Of Posture And Anthropometry, Anna Seydel Jan 2018

Multi-Parented End-Effectors In Optimization-Based Prediction Of Posture And Anthropometry, Anna Seydel

University of Iowa Honors Theses

Improving motion capture processing onto a virtual model is an important research area. Although there has been significant research in this field, little work has been done to determine posture and anthropometry simultaneously with the intent of visualizing the data on virtual models. Many existing techniques are less accurate when applying processed data to a virtual model for biomechanical analysis. This paper presents a novel approach that estimates posture and anthropometry using optimization-based posture prediction to determine joint angles and link-lengths of a virtual model. By including anthropometric design variables, this approach introduces flexible handling of innate variance in subject-model ...


Fingerprinting The Refugio Oil Spill Using Topographic Signal Processing Of Two-Dimensional Gas Chromatographic Images, Rachel Bruflodt Jan 2018

Fingerprinting The Refugio Oil Spill Using Topographic Signal Processing Of Two-Dimensional Gas Chromatographic Images, Rachel Bruflodt

University of Iowa Honors Theses

Oil spill fingerprinting aims to determine whether oil samples originate from the source of the spill or from a different source. This can be done by comparing the composition of hydrocarbons in each oil sample’s two-dimensional gas chromatography (GCxGC) image. In this work, we compare oil samples taken from the 2015 Refugio Oil Spill with oil samples taken elsewhere. We use an approach called Peak Topography Mapping (PTM) which aims to automatically compare oil samples using both target and non-target peaks in the GCxGC image. Results suggest that the non-target peaks analyzed in PTM can provide information beyond that ...


Connecting The Dots: A New Method To Determine Radiation Yield During Electron Beam (Eb) Polymerization Reactions Via Raman Spectroscopy, Renae Kurpius Jan 2018

Connecting The Dots: A New Method To Determine Radiation Yield During Electron Beam (Eb) Polymerization Reactions Via Raman Spectroscopy, Renae Kurpius

University of Iowa Honors Theses

Electron-beam (EB) polymerization is a fast, solvent-free, low-energy means of polymerizing inks, thin films, and coatings such as those used in food packaging. During EB polymerization, accelerated electrons interact with liquid monomer molecules to form radicals, which continue to react with other monomer molecules and form long chain, solid polymers. The final polymer properties are dependent on the monomer chemistry, as well as processing conditions such as dose (i.e., the amount of energy absorbed by the sample), belt speed (i.e., the rate at which the sample travels through the electron-beam unit), and dose rate (i.e., the rate ...


Green Roof Policy Optimization Algorithms And Microsimulations Benefits And Downsides Of Green Roof Incentives And Mandates In San Francisco, Harrison Freund Jan 2018

Green Roof Policy Optimization Algorithms And Microsimulations Benefits And Downsides Of Green Roof Incentives And Mandates In San Francisco, Harrison Freund

University of Iowa Honors Theses

As the 21st Century progresses, developers are becoming more aware of their environmental footprint. As the Green Economy slowly gains its footing, developers will be expected to change current building practices to reflect the increasing demand to adapt to sustainability challenges. One such methodology used by LEED to evaluate the sustainability of a building is the implementation of a green roof, the installment of vegetation on the top of a building. There are many socioecological benefits that justify the implementation of a green roof, which explain why in recent years municipalities have enacted new policies to mandate or incentivize their ...


Clinical Alarms Management In The Intermediate Cardiology And Cardiovascular Intensive Care Units At The University Of Iowa Hospital And Clinics, Aubree Larson Jan 2018

Clinical Alarms Management In The Intermediate Cardiology And Cardiovascular Intensive Care Units At The University Of Iowa Hospital And Clinics, Aubree Larson

University of Iowa Honors Theses

The Intermediate Cardiology Unit (4RC) and the Cardiovascular Intensive Care Unit (CVICU) at the University of Iowa Hospital (UIHC) experience a significant amount of clinical alarms that they have to manage. The clinical alarms monitors have thirty-four different vital signs for patients in the two units, and an alarm will sound when a vital sign or rhythm starts to signal abnormalities. Some of the abnormalities are triggered by a valid clinical condition of the patient, also called an actionable alarm. Alarms that do not fall into the actionable alarm category, called non-actionable and false alarms, have led to alarm fatigue ...


Evaluation Of Ultra-Wideband Position Localization For An Indoor Office Environment, Jake Uribe Jan 2018

Evaluation Of Ultra-Wideband Position Localization For An Indoor Office Environment, Jake Uribe

University of Iowa Honors Theses

Recently, significant improvements have been made in the area of indoor wireless position estimation. Issues of high power consumption and poor accuracy have stifled business and research initiatives to implement this technology to increase efficiency, save money, and obtain critical information. Investigation was done to determine if Decawave’s DWM1001 technology is capable of tracking workers within an office environment to desk level accuracy for both a static (immobile) and dynamic (mobile) tag. Evaluation was conducted under sparse and dense deployment conditions of anchors. Sparse deployments held 1 anchor per 30 meters squared. Dense deployments held 1 anchor per 15 ...


Investigating The Construction Of An Animated 3d Model Using Stereo Photogrammetry, Jiancheng Rong Jan 2018

Investigating The Construction Of An Animated 3d Model Using Stereo Photogrammetry, Jiancheng Rong

University of Iowa Honors Theses

3D modeling and motion capture are technologies that are widely used in many industries including virtual entertainment, clinical research, cinema and military. This technology is used to construct animated 3D models that can be controlled by human operators or designed to perform a series of tasks in a virtual environment. Other uses include scenario research and video gaming. Today, most 3D modeling techniques require a 3D designer to manually create the model. This has the potential to improve the quality and aesthetic of the model, and proves useful in designing video game characters, but is less accurate when the model ...