Engineering Commons^™

Enhancing Urban Water Quality Through Biological-Chemical Treatment: Aquatic Macroinvertebrate Community And Temporal Chlorophyll-A Response, Matthew Chaffee

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

With a growing human population, urbanization is impeding a plethora of natural waterways. Of these, urban ponds play a vital role in nutrient sequestration, flood prevention, and habitat sanctuaries. However, nutrient loading can reduce habitat effectiveness and promote harmful algae blooms. To reduce internal nutrient loads, a biological-chemical treatment strategy consisting of floating treatment wetlands (FTWs) and lanthanum were applied to two urban retention ponds, Densmore and Wilderness Ridge Ponds. To measure effectiveness, chlorophyll-a samples were collected and correlated with Sentinel-2. A novel band algorithm termed 3BR1 produced a strong correlation (R² = 0.72) to physical chlorophyll-a …

Responses Of Maize To Different Irrigation Regimes In Semi-Arid Western Nebraska, Swathi Palle

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

As the “Cornhusker State”, Maize (Zea mays) is an important crop in Nebraska. However, farmers in the state are challenged by unstable supply of surface water and limited groundwater resources. A better understanding of maize's response to water stress that occurs at different growth stages can help implement the best irrigation practices that conserve water while maintaining yields. In this study, we conducted field experiments at the Panhandle Research, Extension, and Education Center to compare the responses of maize to eight irrigation treatments which included both limited and deficit irrigation regimes during 2022 and 2023 growing seasons. Specifically, …

Renovating The Ipmu Via Internet Of Things For Pollutant Emission Estimations In Poultry Facilities, Joshua Dotto

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

The emissions of ammonia (NH₃), particulate matter (PM_2.5), and carbon dioxide (CO₂) are major concerns in poultry facilities. They can pose environmental concerns and nuances. Robust and affordable measurement systems are needed to accurately measure in-barn concentrations and quantify the emissions.

The Intelligent Portable Monitoring Unit (iPMU or PMU3) developed in 2016 was reconstructed into PMU4 to include upgraded NH₃ and PM_2.5 sensors and wireless connectivity for a low-cost, robust, and accurate air quality monitoring device with contactless data transfer using the concept of Internet of Things (IoT). In addition, a user-friendly …

A Wearable Fluorescence Imaging Device For Intraoperative Identification Of Human Brain Tumors, Mehrana Mohtasebi, Chong Huang, Mingjun Zhao, Siavash Mazdeyasna, Xuhui Liu, Samaneh Rabienia Haratbar, Faraneh Fathi, Jinghong Sun, Thomas A. Pittman, Guoqiang Yu

Biomedical Engineering Faculty Publications

Malignant glioma (MG) is the most common type of primary malignant brain tumors. Surgical resection of MG remains the cornerstone of therapy and the extent of resection correlates with patient survival. A limiting factor for resection, however, is the difficulty in differentiating the tumor from normal tissue during surgery. Fluorescence imaging is an emerging technique for real-time intraoperative visualization of MGs and their boundaries. However, most clinical grade neurosurgical operative microscopes with fluorescence imaging ability are hampered by low adoption rates due to high cost, limited portability, limited operation flexibility, and lack of skilled professionals with technical knowledge. To overcome …

A Novel Renewable Energy Powered Zero Liquid Discharge Scheme For Ro Desalination Applications, Mamdouh A. Gadalla, Amr Abdel Fatah, Hany A. Elazab

Chemical and Biochemical Engineering Faculty Research & Creative Works

This work proposes a conceptual model for a Zero Liquid Discharge (ZLD) for Reverse Osmosis (RO) desalination. The model describes a Process Flow Diagram (PFD). The proposed process relies on an RO followed by electrolyser, solar evaporator and mixing tank. The water reject from the RO is split into three fractions, one to an electrolyser to produce H2, another to solar evaporator to produce fresh water, third is remixed with water from the evaporator to reduce the salinity of the RO feed. The hydrogen produced in the electrolyser is burned and its energy is stored using cement blocks. The evaporator …

Evaluation Of Different Decontamination Procedures On Bond Strength To Sound And Caries Affected Dentin Using “No-Wait” Universal Adhesive, Lamiaa M. Moharam, Haidy N. Salem, Sherif Khadr, Ahmed Abdou

Chemical and Biochemical Engineering Faculty Research & Creative Works

Background: Current study aimed to evaluate the effect of different decontamination procedures on micro-shear bond strength (μSBS) of sound (SoD) and caries-affected dentin (CAD) of two universal adhesives after blood-saliva contamination. Methods: One hundred and eighty bovine anterior teeth were prepared and allocated into the respective groups according to tested dentin substrates [SoD, CAD], universal adhesives [Clearfil Bond Universal Quick (UBQ), All-Bond-Universal (ABU)], adhesive contamination stage [none, contamination before and after adhesives light-curing], and according to decontamination procedures [no decontamination, water rinsing, adhesive rebond, Ethylenediaminetetraacetic acid (ETDA) and chlorhexidine (CHX) application]. Universal adhesives were applied according to manufacturer instructions in …

Structural Performance And Resiliency Of Reinforced Concrete Bridge Pier Columns, Multi-Column Piers, And Bridge Systems Subjected To Multiple Hazards – Fire, Collision, And Air Blast, Qusai Abdulkarim Alomari

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Given their close proximity to traffic and improper employment of protective systems, bridges and bridge piers are vulnerable to multi-hazard events triggered by vehicle collisions coupled with correlated and cascading events, such as explosions and fires. Despite recent catastrophic incidents that have highlighted the profound consequences of these extreme demands, including substantial damage, adverse economic impact, and loss of life, there has been a notable lack of research investigating the performance of bridges and bridge structural components under the aforementioned multi-hazards. Furthermore, current bridge design codes do not address these events assuming that, after these destructive events, replacement of the …

On Dyadic Parity Check Codes And Their Generalizations, Meraiah Martinez

Department of Mathematics: Dissertations, Theses, and Student Research

In order to communicate information over a noisy channel, error-correcting codes can be used to ensure that small errors don’t prevent the transmission of a message. One family of codes that has been found to have good properties is low-density parity check (LDPC) codes. These are represented by sparse bipartite graphs and have low complexity graph-based decoding algorithms. Various graphical properties, such as the girth and stopping sets, influence when these algorithms might fail. Additionally, codes based on algebraically structured parity check matrices are desirable in applications due to their compact representations, practical implementation advantages, and tractable decoder performance analysis. …

Development Of A Machine Learning System For Irrigation Decision Support With Disparate Data Streams, Eric Wilkening

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

In recent years, advancements in irrigation technologies have led to increased efficiency in irrigation applications, encompassing the adoption of practices that utilize data-driven irrigation scheduling and leveraging variable rate irrigation (VRI). These technological improvements have the potential to reduce water withdrawals and diversions from both groundwater and surface water sources. However, it is vital to recognize that improved application efficiency does not necessarily equate to increased water availability for future or downstream use. This is particularly crucial in the context of consumptive water use, which refers to water consumed and not returned to the local or sub-regional watershed, representing a …

In Situ Water Sensing Systems: Research On Advancements In Environmental Monitoring, Abigail Seibel

Honors Program: Senior Projects (Public)

In this work, two sensing systems were researched in order to improve in situ environmental monitoring. The first is a pH and Total Alkalinity sensor used to determine these characteristics of sea water. I explored the facets of this sensor over a 7-week internship with Dr. Ellen Briggs in her lab in summer of 2023. The second is a more holistic sensing system that reads temperature, turbidity, and pressure used for studying environmental characteristics of Alaskan bever ponds. Both systems were developed in close collaboration with scientists who are collecting data to better understand the impacts of climate change. Better …

Molecular Control Of Triplet-Pair Spin Polarization And Its Optoelectronic Magnetic Resonance Probes, Obadiah G. Reid, Justin C. Johnson, Joel D. Eaves, Niels H. Damrauer, John E. Anthony

Chemical and Materials Engineering Faculty Publications

Preparing and manipulating pure magnetic states in molecular systems are the key initial requirements for harnessing the power of synthetic chemistry to drive practical quantum sensing and computing technologies. One route for achieving the requisite higher spin states in organic systems exploits the phenomenon of singlet fission, which produces pairs of triplet excited states from initially photoexcited singlets in molecular assemblies with multiple chromophores. The resulting spin states are characterized by total spin (quintet, triplet, or singlet) and its projection onto a specified molecular or magnetic field axis. These excited states are typically highly polarized but exhibit an impure spin …

Optimal Route Planning Using Computer Simulation In The Context Of Distributor-To-Consumer Supply Network, Miriam Aguilera Nava

Open Access Theses & Dissertations

Effective route planning for distribution centers is a multifaceted challenge crucial tobusiness success, as it directly impacts time and cost savings while enhancing overall delivery efficiency. Oversight of proper planning can lead to problems and inefficiencies in the distribution process. Hence, this work undertakes a comparative experiment of two delivery strategies in a distributor-to-consumer supply network. While the first strategy investigates the delivery process by zip area, the second strategy considers the clustering of the areas for more streamlined delivery fulfillment. The effectiveness of the delivery process is gauged based on a set of metrics, including total distance traveled, average …

Development Of Metaheuristic Algorithms For The Efficient Allocation Of Power Flow Control Devices, Eduardo Jose Castillo Fatule

Open Access Theses & Dissertations

No abstract provided.

An Optimization Procedure To Design Nozzle Contours For Hypersonic Wind Tunnels, Omar Antonio Dominguez

Open Access Theses & Dissertations

Supersonic wind tunnels allow scientists and researchers to evaluate and analyze the behaviors of objects under real-life conditions when subjected to supersonic speeds. One of the main complexities when building a wind tunnel is the design of the convergent-divergent nozzle that is used to produce high-speed and high-quality flows. To achieve supersonic speeds, this nozzle adopts a specialized approach that incorporates the complexities of flow compressibility. The compressible effect is accurately evaluated using isentropic relations, allowing for precise determination of stagnation pressure and temperature, and static pressure and temperature relevant to the desired Mach number. Isentropic equations used to define …

Effect Of Multiple Machine Configurations And Wall Thickness On Microstructure And Microhardness Of Laser Powder Bed Fusion (L-Pbf) Additively Manufactured Heat-Treated Inconel 718 Products, Anannya Doris

Open Access Theses & Dissertations

This research examined thin section prototypes having seven nominal thicknesses ranging from 0.1 to 2.0 mm, composing a series of geometric feature build plates manufactured by multiple laser powder bed fusion (L-PBF) machine configurations. The build plates and thin section feature prototypes underwent a full heat treatment cycle per established standards: anneal at 1066°C, SR+HIP at 1163°C, and fully treat-treated by combining SR+HIP+solution treatment at 1066°C and double aging treatment at 760°C and 680°C, respectively. The fully heat-treated (FHT) Inconel 718 wall specimens were sectioned from 16 distinct geometric feature build plates constructed on 15 different L-PBF machines. The thin …

Additively Manufactured Cryogenic Engineered Heat Pipe For Lunar Ice Collection, Mahadi Hasan

Open Access Theses & Dissertations

Nowadays, one of the most talked-about subjects in space exploration is cryogenic heat pipes. These heat pipes are made in a way that allows them to operate without the need for additional power or energy. Evaporated vapor and condensed liquid can be moved by buoyancy forces or capillary forces that are subject to gravity because of the phase shifts of the working fluids moving inside. The cooling solution typically entails a phase transition from liquid to vapor, which can dissipate larger heat fluxes because of the fluid's high latent heat of vaporization. Recent developments in additive manufacturing and micro-nano structures …

Design And Implementation Of Laser Beam Measurements At The Extents Of The Build Platform: Impact Of Beam Location On Melt Pool Geometry, Alexandra Hernandez

Open Access Theses & Dissertations

Laser powder bed fusion (LPBF) is a form of metal additive manufacturing that enables the development of complex parts that cannot readily be made with traditional manufacturing methods. The process utilizes a tightly focused laser beam to selectively melt and fuse layers of powdered metal to create a 3-D part.LPBF is a promising technology, but there are barriers to its adoption in most industries. Mainly, it is difficult to qualify these parts for use, since they are prone to processing defects and part-to-part variation. One source of this is part position on the building plane, especially for multi-part builds where …

Communication Security In Smart Home Iot And Scada Applications, Ismael Holguin

Open Access Theses & Dissertations

The advancements in technology have enabled continuous integration of consumer electronicdevices and sensors to the Internet, creating Internet of Things (IoT) environments for various applications. IoT communication protocols play a significant role in these environments and greatly vary depending on the type of application. In this work, we consider communication protocols in Smart Home IoT and SCADA environments, focus on their security features, and investigate methods to enhance their security. Most of these communication protocols were designed to meet specific communication goals, where security was not a requirement or priority during design. However, due to a shift in the security …

Addressing Current Security And Privacy Limitations In Iot Applications With Differential Privacy, Nicholas Anthony Lopez

Open Access Theses & Dissertations

Over the last decade, billions of devices have been developed to run on the Internet of Things (IoT) domain. IoT has been embedded into everyday tasks so much that the number of devices has outpaced the global population. Some of the main areas of IoT include healthcare, industry, communications, transportation, logistics, and environmental awareness, to name a few. With this greater demand for devices comes an even greater demand for privacy and security. The three main principles of security include confidentiality, integrity, and availability. However, there is no “one size fits all” solution regarding privacy or security. When applied across …

Evaluation Of Inconel 718 Laser Powder Bed Fusion Angled Wall Artifact, Laura Itzel Marquez

Open Access Theses & Dissertations

This research investigates the mechanical properties and microstructural characteristics of Inconel 718 specimens fabricated using different additive manufacturing (AM) systems, focusing on the influence of build orientation. A total of 16 samples were constructed at 45, 60, and 90 degrees to the build platform and analyzed to ascertain variations in mechanical strength, encompassing elongation at break, ultimate tensile strength (UTS), yield stress, and hardness. The comprehensive statistical analysis employs robust methods to quantify the effects of printing parameters on the performance of the builds, thereby identifying the most influential factors in AM processes. Additionally, microstructural analysis through advanced imaging techniques, …

Leveraging Agile Software Methodologies Within Software Development To Introduce A Novel Educational Software Methodology, Montserrat Guadalupe Molina

Open Access Theses & Dissertations

Agile Software Development has been growing increasingly popular in the software engineering industry as a way to produce working software in a quick and people-centered manner. Agile methodologies require practitioners to have strong technical and non-technical skills, such as teamwork, project management, and communication skills. Students graduating from the software engineering discipline have been found to be lacking in these areas, leading to many difficulties faced by recent graduates as they begin their professional careers. Given that Agile Software Development is the most popular software development lifecycle currently used by practitioners in industry, it is important to expose students to …

Analysis Of Travel Behavior At International Border Crossings: Application Of Travel Surveys, Jennifer Areli Moreno Escamilla

Open Access Theses & Dissertations

Transportation planning provides an insight into the demand and traffic distribution of existingconditions of a region and helps identify future transportation needs. The results generated from forecasting models influence many decisions on the selection of transportation projects and funding allocations. Thus, forecasting models require up-to-date trip information to represent trip patterns and generate representative traffic demand analysis in a such complex areas as binational regions. The purpose of this study is to provide an analysis on travel survey methodology applied to collect trip information at international border crossings. Based on the results of the survey, an analysis on trip pattern …

Ultra Wide Band Gap Oxides For Advanced Optoelectronics And Supercapacitor Applications: A Case Study Of Intrinsic And Doped Germanium Dioxide, Paul Gaurav Nalam

Open Access Theses & Dissertations

Germanium dioxide (GeO2) is a metal oxide semiconductor with multiple polymorphs that has recently garnered a significant amount of scientific attention owing to its novel ultra-wide band gap and pseudo-capacitive properties, which can potentially transcend current power electronic, optoelectronic, and supercapacitor technologies. However, due to the difficulty in the synthesis of stable crystalline phases of individual polymorphs of GeO2 thin films, this material system demands complex and resource-intensive deposition techniques to synthesize. An attempt was made to develop cost-effective and scalable deposition techniques to stabilize specific crystalline phases of GeO2 thin films. These phases were further structurally fine-tuned to state …

Enhancing Damage Tolerance Of The Constituents Of Sandwich Composites, Zackery Nieto

Open Access Theses & Dissertations

Composite structures have become a lucrative material choice for researchers throughout various sectors such as green energy, arctic travel, and aerospace application due to their light weight, high-bending to stiffness ratio, and job tailorable applications through material selection. With the increasing demand for new and better composite technologies growing each year it is imperative to investigate new materials and analytical options to help the composite field as a whole grow. In this report various materials and statistical applications have been studied regarding the constituent materials in sandwich composites. For core materials an additive manufactured photoreactive resin has been characterized for …

Ultrasonic Non-Destructive Evaluation Of Additively Manufactured Polymer-Ceramic Composites, Christian Alexander Ruiz

Open Access Theses & Dissertations

Digital light processing (DLP) is an attractive additive manufacturing technique due to its ability to create ceramic parts with complex geometries. DLP uses ultraviolet light to polymerize a slurry comprised of ceramic powder and photosensitive resin in layers to create solid parts. Printing parameters such as light intensity and exposure time are critical when producing these parts. Improper parameters can lead to over or under-curing, adversely impacting print quality and strength. Samples were printed at varying layer exposure times and then tested using ultrasonics to determine the degree of conversion. Additionally, ultrasonics were used as a non-destructive technique to obtain …

Development Of A 3d Printed Conductive Biopolymer For Cardiac Tissue Engineering, Britanny Lizeth Stark

Open Access Theses & Dissertations

Cardiovascular disease (CVD) is the leading cause of death in the US, with approximately 859,000 deaths each year. The major contributor to CVD is Acute Myocardial Infarction (AMI), which causes the death of approximately 25% of the cardiomyocytes present in the left ventricle of the heart. After AMI, the adult human heart has a very limited regenerative capacity. Moreover, the electrical propagation of the myocardium is severely disrupted, making the heart more susceptible to failure and patient death. However, current pharmacological treatments do not address the loss of cardiomyocytes and the disruption of electrical propagation in the heart. Tissue engineering …

Characterization Of Fcc Al-Cu-Ni-Mn-Ag High Entropy Alloy, Gina Zavala Alvarado

Open Access Theses & Dissertations

The effect of Ag on the microstructure developed in Al-Cu-Ni-Mn alloy has been determined. The modified Al-Cu-Ni-Mn alloy by Ag addition shows the presence of three microconstituents consisting of phases rich in (1) Cu, (2) Ni, and (3) Ag. The foregoing alloys heated for 24 hours from 600 to 1000 °C show excellent oxidation resistance. Oxide formation and microstructural changes of the alloy have been characterized by elemental mapping and X-ray diffraction (XRD). Results show that the elements of Al and Mn preferentially oxidize while Cu and Ni provide oxidation resistance to the alloy. Hardness was taken on the alloy …

Enhancing Power System Flexibility Through Efficient Integration Of Facts And Electric Vehicles, Izaz Zunnurain

Open Access Theses & Dissertations

The global transition towards a cleaner and sustainable energy landscape has led to the integration of renewable energy sources and electric vehicles (EVs) into the modern power system, along with their complexities. Due to the high penetration of renewable energy sources and rapid growth of EVs, the power grid often experiences congestion, increasing the overall operating cost of the power system and directly jeopardizing the power stability and quality of the grid. A flexible and resilient power infrastructure that can accommodate the intermittency of renewable energy sources and the adoption of EVs is very much required to ensure the reliability …

Viability Of Magnetic Nanoparticles For Magnetic Hyperthermia Cancer Therapy, Marcos Adrian Garcia

Open Access Theses & Dissertations

Over the last few decades magnetic nanoparticles have gained an extraordinary amount of attention in the science community. Their versatile use in many different research areas such as medicine, engineering and technology and many other areas has made them a popular subject. In this thesis, the synthesis of different systems of magnetic nanoparticles will be explored along with the potential use of the MNP's as viable candidates for Magnetic Hyperthermia Cancer Therapy. With values of over 200 emu/g for Iron-Silver magnetic nanoparticles with particle sizes ranging from 30-70nm and their heating properties under an AC magnetic field. As well of …

Exploration Of Advanced Scan Strategy Capabilities On A Commercial Lpbf System Using Intervector Power Ramping, Antonio York

Open Access Theses & Dissertations

Lack of confidence in the quality of materials produced with metal AM has hinged on the unaddressed defects inherent to the process. Studies have worked to determine defect formation mechanisms and provide adjustments to key process controls. However, these advances have typically been developed in-house on research systems which offer increased and transparent control to the operator. A research gap exists in applying changes in approach of scan strategies to existing commercial systems, which can incentivize adoption while furthering development. The focus of this study is the implementation of inter-vector power ramping on a commercial laser powder bed fusion system …