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2024

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Full-Text Articles in Engineering

Impacts Of Key Degradation Byproducts On Amine Scrubbing For Post-Combustion Carbon Capture, Thomas Jorgensen Jan 2024

Impacts Of Key Degradation Byproducts On Amine Scrubbing For Post-Combustion Carbon Capture, Thomas Jorgensen

Theses and Dissertations--Chemistry

The increasing atmospheric CO2 concentration causes significant concern about global warming and its environmental impact. Industrial sectors, including power generation, transportation, and production factories, contribute most of the anthropogenic sources of CO2 emissions. Researchers search for methods to mitigate these CO2 emissions without compromising the benefits of industrial processes, including CO2 capture, utilization, and sequestration (CCUS). Post-combustion carbon capture (PCCC) by amine scrubbing is the most technology ready CCUS, with various pilot-scale projects worldwide showing small-scale to fully operational plants. While researchers have made significant progress in amine scrubbing, they strive to improve the efficiency and …

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Magnetotransport Properties Of Dirac Semimetal Taco2te2 And Ferromagnetic Weyl Semimetal Co3sn2s2, Samuel Pate Jan 2024

Magnetotransport Properties Of Dirac Semimetal Taco2te2 And Ferromagnetic Weyl Semimetal Co3sn2s2, Samuel Pate

Graduate Research Theses & Dissertations

This dissertation investigates the magnetotransport properties of topological semimetals, specifically focusing on the Dirac semimetal TaCo2Te2 and the Weyl semimetal Co3Sn2S2. In TaCo2Te2, I observed extremely large magnetoresistance that violates Kohler’s rule. Extended Kohler’s rule can be applied with a calculation of Hall factor at low temperatures. I also explored the applicability of the two-band and four-band models of carrier analysis and correlate the region where Kohler’s rule is obeyed to the four-band model. In Co3Sn2S2, I explored the angle-dependent anomalous Hall effect (AHE) near the Kagome plane, revealing a tunable AHE under applied fields and an abrupt disappearance of …

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First Course Portfolio For Tmfd 213: Merchandising I: Textile And Apparel Industry, Na Young Jung Jan 2024

First Course Portfolio For Tmfd 213: Merchandising I: Textile And Apparel Industry, Na Young Jung

UNL Faculty Course Portfolios

This portfolio presents a comprehensive overview of TMFD 213: Merchandising I, a foundational course in the Department of Textiles, Merchandising, and Fashion Design at the University of Nebraska-Lincoln. The course is designed to equip students with critical thinking, analytical skills, and industry-specific knowledge necessary for professional success in the textile and apparel industry. The portfolio outlines the course’s objectives, teaching methodologies, and the impact of instructional strategies on student learning outcomes. It includes detailed analyses of quantitative and qualitative data collected through pre- and post-test surveys, assignments, and reflections. Quantitative results demonstrate significant improvements in key areas such as familiarity …

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Estimation Of Methyl Orange Dye's Molar Absorptivity Using A Photoresistor-Based Photometer, Patricia M. Ludovice, Ramon M. Delos Santos Jan 2024

Estimation Of Methyl Orange Dye's Molar Absorptivity Using A Photoresistor-Based Photometer, Patricia M. Ludovice, Ramon M. Delos Santos

Physics Faculty Publications

The need to further develop solar cell technology, particularly on dye-sensitized solar cells (DSSCs), drives absorption studies of various chemical species. In this study, absorbance analysis of methyl orange (MO) dye was performed using the adapted and modified photoresistor-based photometer of Adams-McNichol et al. [1]. The research aims to improve the stability of the reference setup, while maintaining the accuracy of absorbance results it yields. The methodology includes photometer fabrication, MO dye sample preparation, and the evaluation of MO dye's molar absorptivity in an aqueous solution. Results show that the estimated molar absorptivity of MO using the voltage readings from …

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Photoexcited Charge Carrier Dynamics And Electronic Properties Of Two-Dimensional Mxene, Nb2ctx, Andrew M. Fitzgerald, Emily Sutherland, Tarek A. Elmelegy, Mary Qin Hassig, Julia Martin, Erika Colin-Ulloa, Ken Ngo, Ronald L. Grimm, Joshua R. Uzarski, Michel W. Barsoum, N. Aaron Deskins, Lyubov V. Titova, Kateryna Kushnir Friedman Jan 2024

Photoexcited Charge Carrier Dynamics And Electronic Properties Of Two-Dimensional Mxene, Nb2ctx, Andrew M. Fitzgerald, Emily Sutherland, Tarek A. Elmelegy, Mary Qin Hassig, Julia Martin, Erika Colin-Ulloa, Ken Ngo, Ronald L. Grimm, Joshua R. Uzarski, Michel W. Barsoum, N. Aaron Deskins, Lyubov V. Titova, Kateryna Kushnir Friedman

Mechanical Engineering

Two-dimensional, 2D, niobium carbide MXene, Nb2CTx, has attracted attention due to its extraordinarily high photothermal conversion efficiency that has applications ranging from medicine, for tumor ablation, to solar energy conversion. Here, we characterize its electronic properties and investigate the ultrafast dynamics of its photoexcitations with a goal of shedding light onto the origins of its unique properties. Through density functional theory, DFT, calculations, we find that Nb2CTx is metallic, with a small but finite density of states at the Fermi level for all experimentally relevant terminations of Nb2CTx that can be achieved using HF or molten salt etching of the …

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Corrosion Characteristics Of Ti And Al2o3/Ti Thin Films Sputtered On 316lss, Iman El-Mahallawi, Hanan ِ Abd El-Fattah Dr., Lamiaa Mohamed Dr., Aliaa Abdelfattah Jan 2024

Corrosion Characteristics Of Ti And Al2o3/Ti Thin Films Sputtered On 316lss, Iman El-Mahallawi, Hanan ِ Abd El-Fattah Dr., Lamiaa Mohamed Dr., Aliaa Abdelfattah

Mechanical Engineering

In this work, two thin films (Ti and Al2O3/Ti) were deposited on 316LSS substrates by the physical vapor deposition (PVD) sputtering technique. Heat treatment was applied for thin films at 400 °C for 2 h. Thin films were divided into two groups, The First group cooled in the air (normalized), and the second cooled in the furnace (annealed). The electrochemical characteristics were investigated by potentiodynamic polarization (POT) and impedance spectroscopy (EIS) tests. The corrosion resistance (CRST) for all thin films before and after heat treatment was determined in 3.5% NaCl at room temperature (RT). Scanning electron microscope (SEM), and surface …

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Economic, Environmental, And Social Characteristics Of E-Scooters On Lsu Campus, Mostafa Elseifi, Md Afif Rahman Chowdhury Jan 2024

Economic, Environmental, And Social Characteristics Of E-Scooters On Lsu Campus, Mostafa Elseifi, Md Afif Rahman Chowdhury

Publications

This study provides a comprehensive evaluation of e-scooter technology, with a focus on its environmental, economic, and social impacts, particularly within university settings at the Louisiana State University (LSU) campus. A life-cycle assessment (LCA) was conducted to assess the environmental sustainability of e-scooters, encompassing all stages from raw materials acquisition to end-of-life. The analysis determined that the total CO2 emissions for an e-scooter over a five-year lifespan were approximately 389 kg, with significant reductions possible by improving the lifespan of e-scooters, integrating recycled materials, and utilizing renewable energy sources for charging batteries. The study also compared the environmental and …

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Vehicle Classification Technologies For Toll Collection, Samir Ahmed Jan 2024

Vehicle Classification Technologies For Toll Collection, Samir Ahmed

Publications

Toll facilities (roads, bridges, and tunnels) are intended for revenue generation to pay off the long-term debt issued to finance construction, capacity expansion, operations, and maintenance of these facilities. Tolls are one form of a broad concept known as road pricing. In addition to revenue generation, road pricing is used for other reasons including transportation demand management to reduce peak hour travel and the recurring traffic congestion on some corridors. The aim of this study is to provide the tolling industry with detailed analysis of the suitability of various non‐ pavement‐intrusive vehicle classification technologies (imaging using radar, Lidar, thermal profiling, …

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Designing And Characterizing New Coating Materials To Increase The Corrosion Resistance Of Steel Reinforcement Embedded In Concrete, Homero Castaneda Lopez Jan 2024

Designing And Characterizing New Coating Materials To Increase The Corrosion Resistance Of Steel Reinforcement Embedded In Concrete, Homero Castaneda Lopez

Publications

To develop a sustainable and durable rebar on different elements of the RC as a corrosion control system in regions where corrosion is the leading risk for the infrastructure system. The outcome of this research leads to a comprehensive report that provides methods, testing results, peer review papers, conference proceedings, and guidance for the utilization of rebar for corrosion control actions in RC, capable of long-term performance in harsh corrosive environments (deicing cycle conditions). Workforce development will also take place through a series of outreach activities targeting the broader audience of corrosion, civil, and materials engineers, and potential industrial partners …

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Evaluating The Moisture Susceptibility Of Asphalt Mixes In Oklahoma, Mohamed Elkashef, Samir Ahmed, Sina Mousavi Rad Jan 2024

Evaluating The Moisture Susceptibility Of Asphalt Mixes In Oklahoma, Mohamed Elkashef, Samir Ahmed, Sina Mousavi Rad

Publications

Moisture-induced damage can be detrimental to asphalt pavements. The modified Lottman approach (AASHTO T 283) is used to evaluate the stripping susceptibility of mixtures in Oklahoma. There are concerns about the ability of the AASHTO 283 to predict moisture damage in the field. In this study, the AASHTO T 283, the moisture-induced stress tester (MiST), and the Hamburg wheel tracking (HWT) test are used to evaluate the moisture susceptibility of mixes prepared using different gradations, local aggregate sources, and binders sampled from different refineries in Oklahoma. The mixes were also tested for cracking and rutting using the indirect tensile asphalt …

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Monitoring Of Transportation System Assets Using Synthetic Aperture Radar (Sar) Satellite Data, Anand Puppala, Nripojyoti Biswas, Amit Gajurel Jan 2024

Monitoring Of Transportation System Assets Using Synthetic Aperture Radar (Sar) Satellite Data, Anand Puppala, Nripojyoti Biswas, Amit Gajurel

Publications

This research harnessed both high and medium resolution Synthetic Aperture Radar (SAR) data to delve into infrastructure health assessment. High resolution SAR analyses capable of identifying differences between asphalt and concrete pavement surfaces. Particularly, it was found that Normalized Radar Cross Section (NRCS) values can deftly distinguish pavement types and detect surface anomalies such as alligator cracks in asphalt ahead of conventional methods. On the other hand, Time-Series Interferometric Synthetic Aperture Radar (InSAR) insights, extracted from medium resolution SAR, established a direct linkage between environmental factors and ground deformations. Such findings were corroborated by optical images collected during May 2017 …

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Stabilization Of Expansive Soil Using Geopolymers From Locally Available Resources, Anand Puppala, Miladin Radovic, Nripojyoti Biswas, Sopharith Chou, Oscar Huang Jan 2024

Stabilization Of Expansive Soil Using Geopolymers From Locally Available Resources, Anand Puppala, Miladin Radovic, Nripojyoti Biswas, Sopharith Chou, Oscar Huang

Publications

Traditional calcium-based stabilizers are generally used to stabilize native expansive soils that are often found throughout Region 6. Due to their high carbon footprint, many studies are being conducted to identify a suitable green alternative for stabilizing expansive soils. Geopolymer (GP) received a lot of attention in the past few decades owing to its similar properties to that of ordinary Portland cement (OPC) yet with a lower carbon footprint. Previous studies have shown that metakaolin-based GP is an effective stabilizer to stabilize expansive soils. This study investigated the feasibility of stabilizing native expansive soils with GP synthesized with locally sourced …

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Framework Of Internal Damage Identification In Inhomogeneous Medium Interweaving Wave Scattering Model And Deep Learning, Suyun Ham, Stefan Romanoschi, Yin Chao Wu, Dafnik Saril Kumar David Jan 2024

Framework Of Internal Damage Identification In Inhomogeneous Medium Interweaving Wave Scattering Model And Deep Learning, Suyun Ham, Stefan Romanoschi, Yin Chao Wu, Dafnik Saril Kumar David

Publications

The primary objective of this project is to investigate the framework of internal damage identification in inhomogeneous media (IHM) using deep learning techniques and wave scattering. The study focuses on two main steps: 1) analyzing the wave response pattern in homogeneous media (HM) and 2) characterizing the wave response variation (WRV) in IHM with different aggregate sizes and random distributions. The WRV patterns are then classified and used to predict internal damage using a convolutional neural network (CNN). The accuracy of the finite element (FE) model is verified using laboratory tests with artificial internal crack models of varying depths. The …

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Identifying Wrong-Way Driving Entry Points On Interstate Highways Using Land-Use Impact Assessment And 911 Calls, Farman Mia, Samer Dessouky Jan 2024

Identifying Wrong-Way Driving Entry Points On Interstate Highways Using Land-Use Impact Assessment And 911 Calls, Farman Mia, Samer Dessouky

Publications

The research aims to provide insight into the initiation event of Wrong-way Driving (WWD) on highways. The intense severity of a WWD accident is encouraging the authorities to install mitigation systems that will ensure safety for motorists on highways. The WWD events are mostly resulting of intoxicated driving, where the unconscious driver takes the wrong way to enter the highway and place other motorists into life-threatening danger. This research attempted to explore from basic knowledge of WWD occurrence to examine the origin and driving philosophy of intoxicated drivers from land-use impact and mathematical modeling point of views. To identify the …

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Automated Vehicle Impacts On Underserved Populations, Kate Kyung Hyun, Stephen Mattingly, Katie Kam Jan 2024

Automated Vehicle Impacts On Underserved Populations, Kate Kyung Hyun, Stephen Mattingly, Katie Kam

Publications

This research report describes the scenario framework created to determine the potential role automated vehicles (AVs) have in benefiting and adversely impacting the following underserved populations: people with disabilities and impairments (visually, hearing, physically, intellectually) and with autism spectrum disorder, younger and older populations, immigrants, low income, indigenous, rural, female and LGBTQ+, vulnerable road users (cyclists, pedestrians, low speed riders and drivers), and minority races. After presenting a literature review, three chapters explain the 3 modules of the framework: (1) scenario construction, (2) scenario factors, and (3) GIS methodology for evaluating community level AV impacts. Module 1 describes the use …

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Monotonic And Cyclic Behavior Of High Strength Reinforcing Steel (Hsrs) After High Temperature Exposure, Himan Hojat Jalali, Moein Ebrahimi, Khaled Abuhishmeh, Mohammadamin Soltanianfard Jan 2024

Monotonic And Cyclic Behavior Of High Strength Reinforcing Steel (Hsrs) After High Temperature Exposure, Himan Hojat Jalali, Moein Ebrahimi, Khaled Abuhishmeh, Mohammadamin Soltanianfard

Publications

Conventional reinforced concrete transportation structures in North America often use Grade 40 ksi-60 ksi reinforcing steel. The introduction of high strength reinforcing steel (HSRS) with higher yield strength in the reinforced concrete industry has led to many economic and workability advantages such as construction time saving, reduced labor cost and steel consumption which in turn alleviates congestion of reinforcement, savings in transportation and deliveries that finally results in lower carbon emission. Despite these benefits, many states, including those in Region 6, have not widely adopted the use of higher strength reinforcing steels in practice due to lack of knowledge and …

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Green Mobility In Texas: Comparative Environmental Impacts And Lifecycle Cost Analysis Of Hybrid, Electric, And Hydrogen Fuel Cell Cars, Raghava R. Kommalapati, Hongbo Du, Md Jobair Bin Alam Jan 2024

Green Mobility In Texas: Comparative Environmental Impacts And Lifecycle Cost Analysis Of Hybrid, Electric, And Hydrogen Fuel Cell Cars, Raghava R. Kommalapati, Hongbo Du, Md Jobair Bin Alam

Publications

Compared to gasoline/diesel cars and battery electric cars (BECs), hydrogen fuel cell cars (HFCCs) are relatively new. Two main advantages of HFCCs over electric vehicles are no special requirements for heavy batteries and long charging time. There is no HFCC in Texas; thus, exploring the use of electricity or hydrogen produced from renewable energies for personal cars and mitigating vehicle emissions is critical for sustaining a long-term decarburization strategy for megacities like Houston and Dallas. This project addressed this critical gap and developed environmental impacts and cost assessments for hybrid gasoline cars, BECs, and HFCCs in Texas under several possible …

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Smart3pm: Smart Pavement Monitoring, Management, And Maintenance, Damien Stephens, Mena Souliman, Mukul Shirvaikar, Samer Dessouky Jan 2024

Smart3pm: Smart Pavement Monitoring, Management, And Maintenance, Damien Stephens, Mena Souliman, Mukul Shirvaikar, Samer Dessouky

Publications

An application specific multi-platform smartphone application can utilize on-board accelerometer, gyroscope, and GPS sensors, along with software derived signals from the same sensors, to sample vibrational and geolocation datasets to capture pavement distresses such as potholes when mounted in a standardized configuration in a vehicle. Several observations were made with regard to the signals obtained from the accelerometer, gyroscope, and GPS sensors, and it was determined that the raw sensor outputs are capable of sampling statistically significant datasets which can be used to distinguish pavement distress from normal driving conditions. Furthermore, an approximate sensor noise margin is established, and a …

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Design Of 3d Printable Eco-Concrete By Utilizing Rheology Modifiers For Sustainable Infrastructure, Maryam Hojati, Muhammad Saeed Zafar Jan 2024

Design Of 3d Printable Eco-Concrete By Utilizing Rheology Modifiers For Sustainable Infrastructure, Maryam Hojati, Muhammad Saeed Zafar

Publications

In recent years, 3D printing technology has gained significant momentum across various industries within the construction sector, 3D printing has emerged as a promising technique; however, there are challenges associated with designing suitable construction materials and adjusting their properties for the 3D printing process. One of the key considerations in this regard is the rheological properties, encompassing parameters such as viscosity, yield stress, and thixotropy. These properties play a pivotal role in shaping the characteristics of 3D-printed concrete, both in its fresh and hardened states, including buildability, extrudability, and mechanical performance. Researchers have traditionally relied on chemical admixtures, such as …

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Development Of A Web Application For Traffic Accident Mapping And Analysis, Susan Bogus Halter, Su Zhang, Arian Golrokh Amin Jan 2024

Development Of A Web Application For Traffic Accident Mapping And Analysis, Susan Bogus Halter, Su Zhang, Arian Golrokh Amin

Publications

It is widely accepted that road traffic safety is a significant public health issue. One of the effective ways to improve road traffic safety is analyzing crash data to understand where traffic accidents occur, identify associated spatial and temporal patterns, and determine causation. In the State of New Mexico, locations of traffic accidents are currently visualized using a variety of static maps. Although these statics maps are easier to create and producers can control how users view the data, users cannot customize these maps to meet their special needs. That being said, new maps need to be created for any …

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Motorcycle Crash Analysis, Hatim Sharif, Samer Dessouky Jan 2024

Motorcycle Crash Analysis, Hatim Sharif, Samer Dessouky

Publications

The Fatality Analysis Reporting System database shows that, in stark contrast to the 34 percent decline in non-motorcyclist crash–related fatalities, motorcyclist crash–related fatalities were up 86 percent with only three year-to-year declines since 1997, while non-motorcyclist crash–related fatalities had 13 year-to-year declines since 1997. At the national level, the rate of motorcyclist fatalities per vehicle mile traveled is 29 times higher than the rate among passenger car occupants, with overall injury rates approximately five times higher among motorcyclists than passenger car occupants. Given the frequency of motorcycle crashes and their staggering toll in terms of loss of life and economic …

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Bridge Inspection Training And Enhanced Operations Using Augmented Reality, Fernando Moreu, Ali Mohammadkhorasani, Kaveh Malek Jan 2024

Bridge Inspection Training And Enhanced Operations Using Augmented Reality, Fernando Moreu, Ali Mohammadkhorasani, Kaveh Malek

Publications

This research project focused on the innovative application of Augmented Reality (AR) headsets to enhance bridge inspection processes and inspection training. The study encompassed the visualization of 3D point cloud data, utilized the Eye-Tracking features of AR headsets for inspection quantification, evaluate the applicability of AR in the bridge inspection training and instruction of an AR virtual menu for the in-field bridge inspection. The primary tasks included establishing a database connection for AR headset, designing an AR menu tailored for bridge inspection, devising an evaluation method based on Eye-Tracking capabilities, and integrating AR into bridge inspection training. Once the technical …

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Deep Reinforcement Learning-Based Digital Twin For Risk Improved Decision Making In Transportation Construction, Yong-Cheol Lee, Anisha Deria Jan 2024

Deep Reinforcement Learning-Based Digital Twin For Risk Improved Decision Making In Transportation Construction, Yong-Cheol Lee, Anisha Deria

Publications

Organizing and overseeing a large number of transportation construction and maintenance projects that generally entail several miles of a worksite are a critical burden for each DOT. In addition, it requires manual monitoring of a project or construction managers to identify a progress status, a work activity, and a safety issue in a job site. Because of the projected huge volume, complexity, significant impacts of future transportation infrastructure projects, it is evident that we are now facing a critical need to create a means of improving the results of work zone management and evaluating their impacts on our society. In …

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The Effect Of Covid-19 Lockdown On Traffic Crashes In Texas., Hatim Sharif, Samer Dessouky Jan 2024

The Effect Of Covid-19 Lockdown On Traffic Crashes In Texas., Hatim Sharif, Samer Dessouky

Publications

An analysis of traffic patterns during COVID-19 has identified that reduction in the miles traveled has a significant negative correlation with COVID-19 cases and deaths across the USA. Preliminary statistics in the US suggest an increase in fatal crashes over the period of the lockdown in comparison to the same period in previous years. Moreover, while total crashes are down, motor vehicle crashes involving non-motorists became more prevalent. At the same time, non-motorist traffic has increased while motor vehicle traffic and crashes have shifted to the local systems. The main goal of this research is to perform a comprehensive evaluation …

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Calcined Clays As Alternative Supplementary Cementitious Material And Precursor For Geopolymer Binders In Transportation Infrastructure, Hassan Noorvand, Miladin Radovic, Marwa Hassan, Adriana A. Alvarado, Oscar Huang Jan 2024

Calcined Clays As Alternative Supplementary Cementitious Material And Precursor For Geopolymer Binders In Transportation Infrastructure, Hassan Noorvand, Miladin Radovic, Marwa Hassan, Adriana A. Alvarado, Oscar Huang

Publications

This project aimed to assess the feasibility of using locally sourced calcined kaolinitic clays both as supplementary cementitious materials (SCMs) and as precursors for synthesizing geopolymers (GPs). For SCMs, a comprehensive set of characterizations was conducted, including X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), particle size analysis, and loss on ignition (LOI), along with evaluations of concrete properties such as strength activity index (SAI), slump, air content, compressive strength, and surface resistivity. For GPs, compressive strength was tested. The study yielded several key findings: (1) Three types of calcined clays (CCs) were analyzed based …

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Prediction Of Moisture Resistance Of Polymeric Asphalt Binders Through The Atomic Force Microscopy (Afm) Technique, Zahid Hossain, Ashraf Elsayed, Khaja Sameer Sadat Jan 2024

Prediction Of Moisture Resistance Of Polymeric Asphalt Binders Through The Atomic Force Microscopy (Afm) Technique, Zahid Hossain, Ashraf Elsayed, Khaja Sameer Sadat

Publications

Moisture damage is a significant concern for state Departments of Transportation (DOTs) and other agencies due to its adverse impact on pavement performance as well as longevity. The main focus of the current study project is to quantify, at the molecular level, the interaction between binder and aggregate at the interface level in the form of adhesion forces between bitumen samples and minerals of various chemical compositions. First of all, A thorough review of the literature on moisture degradation in asphalts was conducted. Based on the literature review, a comprehensive project plan and test matrix were created. Binder samples from …

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Early-Age Strength Monitoring Of Sensor-Embedded 3d Printed Structures, Ali Kazemian, Marwa Hassan, Hassan Noorvand, Gabriel Arce, Kasra Banijamali Jan 2024

Early-Age Strength Monitoring Of Sensor-Embedded 3d Printed Structures, Ali Kazemian, Marwa Hassan, Hassan Noorvand, Gabriel Arce, Kasra Banijamali

Publications

Construction 3D printing (C3DP) is an automated technology that has the potential to reduce the construction time and cost by utilizing different types of robotic systems. Due to the absence of formwork in C3DP, potential excessive water evaporation can cause issues to the freshly-printed structures that are exposed to the ambient curing condition. Moreover, the 3D printed elements should carry the service loads in a short time after printing to provide a load-bearing capacity. Destructive and non-destructive methods are the two types of methods that are being used in the construction industry for quality monitoring. Due to the time-consuming nature …

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Design And Fabrication Of Quantum Cascade Laser Tree Arrays, Luke Milbocker Jan 2024

Design And Fabrication Of Quantum Cascade Laser Tree Arrays, Luke Milbocker

Graduate Thesis and Dissertation 2023-2024

Quantum cascade lasers (QCLs) are semiconductor lasers that can be designed to emit over a very broad wavelength range from the mid-wave infrared (MWIR) to terahertz frequencies. Their compact size and ability to output several watts of MWIR or long-wave infrared (LWIR) radiation makes them ideal sources for directional infrared counter measures (DIRCM). This application is fueling demand for ever more powerful QCLs, but power gains from single QCLs have largely stagnated in recent years. Novel waveguide geometries such as tree-arrays seek to increase output power delivered in a single high-quality beam. InGaAs/AlInAs tree array QCLs based on ridge waveguides …

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Comparative Study Of Robotic And Manual Welding In A Low Volume-High Mix Manufacturing Environment: Case Study Of Lift Ring, Sai Sasank Pothamsetti Jan 2024

Comparative Study Of Robotic And Manual Welding In A Low Volume-High Mix Manufacturing Environment: Case Study Of Lift Ring, Sai Sasank Pothamsetti

All Graduate Theses, Dissertations, and Other Capstone Projects

A comparative study of robotic and manual welding in a low volume high mix manufacturing environment focusing on a truck body part named the lift ring to see if there is a benefit of incorporating robotic welding into the production line. By utilizing predetermined time studies such as Methods Time Measurement 1(MTM-1) and Maynard’s Operation Sequence Technique (MOST) in conjunction with normal time and motion study to see which method of time study can be used to extrapolate the times of production for higher number of parts. MTM-1 and MOST were used for a detailed time and motion analysis which …

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Comparative Study Of Robotic And Manual Welding In A Low Volume-High Mix Manufacturing Environment: Case Study Of Tail Gate, Aditya Suggula Jan 2024

Comparative Study Of Robotic And Manual Welding In A Low Volume-High Mix Manufacturing Environment: Case Study Of Tail Gate, Aditya Suggula

All Graduate Theses, Dissertations, and Other Capstone Projects

Our study rigorously compared the efficacy of Methods-Time Measurement (MTM 1) and Maynard Operation Sequence Technique (MOST) against actual production times to identify the most accurate and efficient time management frameworks for manufacturing processes. We aimed to discern which method better predicts job completion times in a real-world setting, using a case study that included both manual and robotic welding in the assembly of a truck body part, the tipper tailgate. We discovered notable discrepancies between the predetermined time systems and actual observations, particularly in manual welding tasks. These differences highlighted the complexity of manual tasks, which involve intricate movements …

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