Engineering Commons^™

Design, Build, And Analysis Of A Compressed Natural Gas Direct Injection Compression Ignition Single Cylinder Research Engine, Tyler Miller

Dissertations, Master's Theses and Master's Reports

Both experimental and simulation efforts have been employed to further advance the design and build of a single cylinder research engine. The engine will aid in advancing technology and understanding the operation of compression-ignition (CI) engines using natural gas within the heavy-duty engine industry. The basis for the engine is a Cummins 15L ISX engine that has been modified, retrofitted, and instrumented to allow for late-cycle direct-injection of high-pressure compressed natural gas. Along with the engine build, a one-dimensional GT-Power simulation model has been created and used to analyze the engine operation and specify components including the engine compression ratio …

Numerical Investigation Of Spray Characterization Of Heater-Gdi System, Ashwin Karthik Purushothaman

Dissertations, Master's Theses and Master's Reports

Gasoline engines require fuel enrichment at low temperature cranking (cold start) conditions for efficient engine operation. Since the amount of fuel injected is high at cold start to compensate low fuel evaporation, fuel sprays tend to impinge on the cold surfaces of the piston and cylinder walls leading to the formation of excessive unburned hydrocarbons. One of the ways to ensure reliable cold start performance and to reduce UHC emissions is to have the fuel subjected to preheating. The objective of this study is to investigate the effects of fuel preheating on Gasoline Direct Injection sprays to improve the mixture …

Metalimnetic Oxygen Minimum In Green Lake, Wisconsin, Mahta Naziri Saeed

Dissertations, Master's Theses and Master's Reports

Green Lake, located in Green Lake County, Wisconsin, has been experiencing summer Metalimnetic Oxygen Minima (MOM). The severity of the MOM has increased in recent years and the lake was listed as impaired in 2014. To investigate the MOM, the lake was monitored during 2017 and 2018 at two sites using moored temperature and oxygen sensors recording at 1-hour intervals. Using these data, a hydrodynamic model (Simstrat) was configured for the lake. A new model was then developed to simulate the oxygen changes in the lake. Productivity, respiration, sediment oxygen demand (SOD) and fluxes were included, and hydrodynamics were driven …

Optimization Of Shape And Control Of Linear And Nonlinear Wave Energy Converters, Jiajun Song

Dissertations, Master's Theses and Master's Reports

In this dissertation, we address the optimal control and shape optimization of Wave Energy Converters. The wave energy converters considered in this study are the single-body heaving wave energy converters, and the two-body heaving wave energy converters. Different types of wave energy converters are modeled mathematically, and different optimal controls are developed for them. The concept of shape optimization is introduced in this dissertation; the goal is to leverage nonlinear hydrodynamic forces which are dependent on the buoy shape. In this dissertation, shape optimization is carried out and its impact on energy extraction is investigated. In all the studies conducted …

Dynamic Testing: An Experimental Approach To Defect Identification In Additive Manufactured Parts, Aimee Allen

Dissertations, Master's Theses and Master's Reports

Today’s additive manufacturing (AM) industry produces specialized parts at low volume or with complex geometries. Traditional testing methods are effective, but costly and time consuming to perform. The AM industry lacks an optimized testing method for identifying internal defects that occur in parts. The evaluation of multiple parts printed on the same build plate for internal defects using various nondestructive (dynamic) testing techniques is presented. From these experiments, perspective was gained on when and how dynamic testing can be used to find defects. Insight gained from these experiments can help the industry in future testing for internal defects.

Multiscale Modeling Of Carbon Fibers/Graphene Nanoplatelets/Epoxy Hybrid Composites For Aerospace Applications, Hashim Al Mahmud

Dissertations, Master's Theses and Master's Reports

Significant research effort has been dedicated for decades to improve the mechanical properties of aerospace polymer-based composite materials. Lightweight epoxy-based composite materials have increasingly replaced the comparatively heavy and expensive metal alloys used in aeronautical and aerospace structural components. In particular, carbon fibers (CF)/graphene nanoplatelets (GNP)/epoxy hybrid composites can be used for this purpose owing to their high specific stiffness and strength. Therefore, this work has been completed to design, predict, and optimize the effective mechanical properties of CF/GNP/epoxy composite materials at different length scales using a multiscale modeling approach. The work-flow of modeling involves a first step of using …

Effect Of Cerium And Magnesium Additions On The Strength And Morphology Of The Intermetallic Compound Layers In Aluminum-Steel Dissimilar Castings, Matt Thomas

Dissertations, Master's Theses and Master's Reports

Dissimilar castings are under investigation due to their light-weighting opportunities within the automotive industry. In this case, dissimilar castings consist of a solid steel core and a poured aluminum component. The strength and integrity of the casting relies on the coherency of the bond between the two components; by optimizing the metallurgical component of the bonding phenomena, the weight and complexity of the insert can be reduced, further increasing the light-weighting opportunities. An interface comprised of intermetallics, generally Fe₄Al₁₃ and Fe₂Al₅, forms between the two components with the latter forming nearest the steel. …

Lagrangian Relaxation Method For Integrated Vehicles And Drones Routing Model, Perawit Charoenwut

Chulalongkorn University Theses and Dissertations (Chula ETD)

Nowadays, e-commerce increases parcel transportation demand year by year. Many companies are seeking the way to improve performance of delivery service and cost-efficiency. One among many solutions is using a drone attached with a truck for the last mile delivery. A drone can be launched from either depot or truck and returned to the depot or wait for the truck to take them back from the docking station around the delivery area. The vehicle routing problem with drones considers truck- and drone-route simultaneously. It is an enormous problem that cannot be solved by a normal linear programming method. This research …

Effects Of Oxygen Modification On The Structural And Magnetic Properties Of Highly Epitaxial La0.7sr0.3mno3 (Lsmo) Thin Films, Shalini Kumari, Navid Mottaghi, Chih-Yeh Huang, Robbyn Trappen, Ghadendra Bhandari, Saeed Yousefi, Guerau Cabrera, Mohindar S. Seehra, Mikel B. Holcomb

Faculty & Staff Scholarship

La0.7Sr0.3MnO3, a strong semi-metallic ferromagnet having robust spin polarization and magnetic transition temperature (TC) well above 300 K, has attracted significant attention as a possible candidate for a wide range of memory, spintronic, and multifunctional devices. Since varying the oxygen partial pressure during growth is likely to change the structural and other physical functionalities of La0.7Sr0.3MnO3 (LSMO) films, here we report detailed investigations on structure, along with magnetic behavior of LSMO films with same thickness (~30 nm) but synthesized at various oxygen partial pressures: 10, 30, 50, 100, 150, 200 and 250 mTorr. The observation of only ( …

Ground And Aerial Robots For Agricultural Production: Opportunities And Challenges, Santosh Pitla, Sreekala Bajwa, Santosh Bhusal, Tom Brumm, Tami M. Brown-Brandl, Dennis R. Buckmaster, Isabella Condotta, John Fulton, Todd J. Janzen, Manoj Karkee, Mario Lopez, Robert Moorhead, Michael Sama, Leon Schumacher, Scott Shearer, Alex Thomasson

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Crop and animal production techniques have changed significantly over the last century. In the early 1900s, animal power was replaced by tractor power that resulted in tremendous improvements in field productivity, which subsequently laid foundation for mechanized agriculture. While precision agriculture has enabled site-specific management of crop inputs for improved yields and quality, precision livestock farming has boosted efficiencies in animal and dairy industries. By 2020, highly automated systems are employed in crop and animal agriculture to increase input efficiency and agricultural output with reduced adverse impact on the environment. Ground and aerial robots combined with artificial intelligence (AI) techniques …

การลดของเสียในกระบวนการประกอบสายส่งสัญญาณทางแสง (Active Optical Cable), อาภานวล แก้วกาหลง

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้มีวัตถุประสงค์เพื่อปรับปรุงกระบวนการประกอบสายส่งสัญญาณทางแสง ที่ระดับความเร็ว 100Gb/s ซึ่งเป็นเทคโนโลยีการส่งสัญญาณสำหรับดาต้าเซ็นเตอร์ที่เติบโตอย่างต่อเนื่อง โดยประยุกต์ใช้เครื่องมือปรับปรุงคุณภาพตามแนวทางซิกซ์ ซิกมา หรือ DMAIC ประกอบด้วย (1) ระยะนิยามปัญหา พิจารณาอัตราผลิตผลดีในกระบวนการประกอบระดับออพติคอลเอนจิน พบว่ากระบวนการวัดกำลังแสงขาออกมีสัดส่วนของเสียเฉลี่ยต่ำที่สุด ประมาณ 10.29% ซึ่งเป็นตัวชี้วัดว่ากระบวนการวางเลนส์ด้วยวิธีการแบบแพสซิพ (Passive Alignment technique) ซึ่งเป็นวิธีการวางตำแหน่งเลนส์โดยใช้ภาพเอกลักษณ์และการคำนวณระยะสัมพัทธ์ระหว่างกึ่งกลางของเลนส์ และกึ่งกลางของเลเซอร์ VCSEL ยังมีคุณภาพดีไม่เพียงพอ (2) ระยะการวัด การวิเคราะห์ความพ้องกันของระบบวัดกำลังแสงขาออก โดยใช้ข้อมูลแบบนับ (Attribute gage R&R) แสดงให้เห็นว่าระบบวัดมีความสามารถในการวัดซ้ำ, วัดได้อย่างถูกต้อง, และระบบมีความพ้องกันดี (Kappa > 0.9) โดยค่า Cpk และ Ppk จากการวิเคราะห์ความสามารถของกระบวนการ เป็น 0.923 และ 0.423 ตามลำดับ (3) ระยะวิเคราะห์หาสาเหตุของปัญหาด้วยการทดสอบสมมติฐานสัดส่วนประชากร 2 กลุ่ม พบว่ามี 4 ปัจจัยที่ส่งผลต่อสัดส่วนของเสียได้แก่ อัลกอริทึมการหาอไลน์เมนท์ออฟเซ็ต, แผ่นวงจรรวมที่ผลิตจากแหล่งที่ต่างกัน, ระนาบแกน Z หรือบอนด์ไลน์, และอุณหภูมิการอบกาวให้แห้งหลังวางเลนส์ (4) การดำเนินการปรับปรุง และ (5) การติดตามผล ซึ่งหลังการปรับปรุงพบว่าว่าสัดส่วนของเสียลดลงจาก 10.29% เหลือ 1.98% หรือลดลง 80% กระบวนการมี Cpk และ Ppk ดีขึ้นเป็น 1.187 และ 0.687 ตามลำดับ

การสังเคราะห์โบรอนคาร์ไบด์จากรังไหมและกรดบอริก, กานต์ชนก ภูผาทอง

Chulalongkorn University Theses and Dissertations (Chula ETD)

โบรอนคาร์ไบด์เป็นวัสดุที่ได้รับความสนใจอย่างแพร่หลาย เนื่องจากมีความแข็งสูงประกอบกับมีสมบัติเชิงกลและทางกายภาพที่เป็นเลิศ จึงถูกนำไปใช้งานที่ต้องการความทนทานในสภาวะพิเศษหลากหลายด้าน ในงานวิจัยนี้ ผู้วิจัยได้มีความพยายามที่จะสังเคราะห์โบรอนคาร์ไบด์ที่อุณหภูมิต่ำ จากรังไหมและกรดบอริก เนื่องจากรังไหมมีหมู่ฟังก์ชันไฮดรอกซิลภายในโครงสร้าง สามารถสร้างพันธะ B-O-C ระหว่างกระบวนการเตรียมสารผสมตั้งต้นร่วมกับกรดบอริก รังไหมจะถูกจุ่มแช่ในสารละลายกรดบอริก จากนั้นนำไปสังเคราะห์โดยผ่านหรือไม่ผ่านขั้นตอนแคลไซน์ ผลิตภัณฑ์จากการสังเคราะห์ได้ถูกนำมาตรวจสอบองค์ประกอบเฟสด้วยเทคนิคการเลี้ยวเบนของรังสีเอ็กซ์ จากการทดลองปรับเปลี่ยนตัวแปรต่างๆในกระบวนการ พบว่า การจุ่มแช่รังไหม 1 กรัม ในสารละลายที่เตรียมกรดบอริก 2 และ 4 กรัม ในน้ำปราศจากไอออน 150 มิลลิลิตร เป็นเวลา 4 ชั่วโมง ณ อุณหภูมิห้อง เมื่อผ่านการอบและสังเคราะห์ที่อุณหภูมิ 1450 องศาเซลเซียส เป็นเวลา 5 ชั่วโมง ในบรรยากาศก๊าซอาร์กอน องค์ประกอบเฟสของผลิตภัณฑ์ประกอบด้วยโบรอนคาร์ไบด์ โดยมีคาร์บอนปรากฏเป็นเฟสหลักอยู่ในระบบ เมื่อลดอุณหภูมิการสังเคราะห์เป็น 1350 องศาเซลเซียส ไม่พบโบรอนคาร์ไบด์ในองค์ประกอบเฟสของผลิตภัณฑ์ นอกจากนี้ เมื่อนำกระบวนการไฮโดรเทอร์มัลที่ 180 องศาเซลเซียส 4 ชั่วโมง มาใช้ร่วมในการสังเคราะห์ พบว่าไม่สามารถพัฒนาการเกิดเฟสโบรอนคาร์ไบด์ให้เพิ่มขึ้น อย่างไรก็ตาม งานวิจัยในส่วนนี้ยังคงต้องการการศึกษาทดลองเพิ่มเติมเพื่อยืนยันผล

การสังเคราะห์โบรอนคาร์ไบด์จากไตรเมทิลบอเรตและแบคทีเรียเซลลูโลส, รณภูมิ ไชยตระการกิจ

Chulalongkorn University Theses and Dissertations (Chula ETD)

โบรอนคาร์ไบด์เป็นวัสดุเซรามิกที่มีความแข็งสูงมาก และมีสมบัติเชิงกลยอดเยี่ยมที่อุณหภูมิสูง งานวิจัยนี้มีความพยายามที่จะสังเคราะห์โบรอนคาร์ไบด์ที่อุณหภูมิต่ำด้วยวิธีการคาร์โบเทอร์มิกรีดันชัน โดยใช้สารตั้งต้นได้แก่ ไตรเมทิลบอเรตเป็นแหล่งโบรอนและแบคทีเรียเซลลูโลสเป็นแหล่งคาร์บอน จากการตรวจสอบหมู่ฟังก์ชันของสารผสมตั้งต้น พบพันธะ B-O-C ซึ่งเอื้อต่อการเกิดเฟสโบรอนคาร์ไบด์ในผลิตภัณฑ์ จากการตรวจสอบองค์ประกอบเฟสในผลิตภัณฑ์ที่เตรียมสารผสมตั้งต้นโดยใช้น้ำปราศจากไอออนเป็นตัวทำละลายผ่านการสังเคราะห์ที่อุณหภูมิ 1450 องศาเซลเซียส เป็นเวลา 5 ชั่วโมง ในบรรยากาศก๊าซอาร์กอน โดยไม่ผ่านขั้นตอนการเผาแคลไซน์ พบว่ามีโบรอนคาร์ไบด์เป็นเฟสหลัก และยังคงพบคาร์บอนเป็นมลทินในผลิตภัณฑ์ โครงสร้างจุลภาคของผลิตภัณฑ์ที่สังเคราะห์ได้ประกอบด้วยผลึกโบรอนคาร์ไบด์รูปร่างหลายเหลี่ยมขนาด 1-5 ไมครอน เป็นส่วนใหญ่ โดยมีอนุภาครูปร่างคล้ายแบคทีเรียเซลลูโลสที่ยังไม่ได้ทำปฏิกิริยากระจายในโครงสร้าง

Grain Boundary Defect Passivation Of Mixed Cation Perovskite Solar Cell To Improve Device Performance, Sheikh Ifatur Rahman

Electronic Theses and Dissertations

Rigorous research on perovskite solar cell for more than ten years all over the world has led the rapid development of perovskite technology giving us device efficiency of 25.2%, surpassing the performance of traditional thin-film solar technologies on small scale devices (<1cm²). Perovskite material has excellent electronic and optical properties making it greatly suitable for PV application. The device fabrication process being simple with low cost and solution processability has led the researchers to visualize high efficiency scalable devices. Due to solution process fabrication method the defects in the materials causes the devices perform less than anticipated. These …

Discharge Coefficients For Rectangular Suppressed And Submerged Sluice Gates, Charles M. Burt, Albert J. Clemmens, Kyle Feist

BioResource and Agricultural Engineering

Two sizes of sluice gates were tested in submerged conditions with a variety of flow rates and gate openings. A new equation was developed for flow rate prediction.

Video And Image Super-Resolution Via Deep Learning With Attention Mechanism, Xuan Xu

Graduate Theses, Dissertations, and Problem Reports (ETD)

Image demosaicing, image super-resolution and video super-resolution are three important tasks in color imaging pipeline. Demosaicing deals with the recovery of missing color information and generation of full-resolution color images from so-called Color filter Array (CFA) such as Bayer pattern. Image super-resolution aims at increasing the spatial resolution and enhance important structures (e.g., edges and textures) in super-resolved images. Both spatial and temporal dependency are important to the task of video super-resolution, which has received increasingly more attention in recent years. Traditional solutions to these three low-level vision tasks lack generalization capability especially for real-world data. Recently, deep learning methods …

Assessment Of Heat Stress For Outdoor Work Conditions In Saudi Arabia, Jamal Alanazi

Graduate Theses, Dissertations, and Problem Reports (ETD)

Outdoor workers have an increased risk of heat stress in Saudi Arabia since it is one of the hottest places in the Middle East. Recently, the government decided to limit outdoor work hours during the months of June, July, and August every year, and banned working under the direct sunlight from 12:00 to 03:00 p.m., although outdoor workers in the petroleum, natural gas, or emergency maintenance work industries are exempt from this prohibition. Traditionally, the efforts by safety and health professionals to mitigate work-related heat injury has been directed toward the assessment of environmental heat stress (e.g., wet-bulb globe temperature), …

Plasmon-Enhanced Optical Probes For Sensing Of Drug Metabolite, Jennifer Boryczka

Graduate Theses, Dissertations, and Problem Reports (ETD)

An Au@SiO₂ core-shell nanostar structure was synthesized along with CuInS2 quantum dots. The quantum dots display near-infrared fluorescence. In this work, the nanostar structure was functionalized with antibodies and then was utilized as a SERS probe for drug metabolite detection. Drugs are an illicit substance that police, medics, and hospitals need to know if an individual is under the influence of but that individual will not always be willing or able to provide that information. A sensor based on this new probe has been developed for detection of drug metabolites in buffer.

Transit Agencies Performance Assessment And Implications, Parisa Hajibabaee

Graduate Theses, Dissertations, and Problem Reports (ETD)

Although most transit systems operate in small urban and rural areas in the United States, these systems have rarely received the same attention as their urban counterparts, both in terms of ensuring the efficiency and effectiveness of their operations and understanding the factors that affect their performance. This thesis's main goals are to assess the performance of rural and small urban public transit agencies and help them evaluate adopting a ridehailing program, thereby improving their performance. We applied operations research and decision-making tools to two public transit projects in small urban and rural areas. The first project focuses on three …

The Influence Of Spatial Variance On Rock Strength And Mechanism Of Failure, Danqing Gao

Graduate Theses, Dissertations, and Problem Reports (ETD)

The heterogeneity in the rock formation affects both rock behavior and the strength. The effect of heterogeneity is observed both at the laboratory scale and at the rockmass level. The mechanical properties of intact rock vary considerably at laboratory scale and often an average value is used for design purposes. Similarly, the values are arbitrarily scaled when used at rockmass level. In underground coal mines, the effect of variability of properties is often observed with the erratic roof failure events that occur throughout the mine. The approach often was to use the deterministic values from limited site data to estimate …

Environment Search Planning Subject To High Robot Localization Uncertainty, Jared Joseph Beard

Graduate Theses, Dissertations, and Problem Reports (ETD)

As robots find applications in more complex roles, ranging from search and rescue to healthcare and services, they must be robust to greater levels of localization uncertainty and uncertainty about their environments. Without consideration for such uncertainties, robots will not be able to compensate accordingly, potentially leading to mission failure or injury to bystanders. This work addresses the task of searching a 2D area while reducing localization uncertainty. Wherein, the environment provides low uncertainty pose updates from beacons with a short range, covering only part of the environment. Otherwise the robot localizes using dead reckoning, relying on wheel encoder and …

An Examination To Pathways Powering Car Using Clean Energy, Marina Miranda

Graduate Theses, Dissertations, and Problem Reports (ETD)

Traditional vehicles powered by internal combustion engines contribute significantly to increasing emissions of greenhouses gasses (GHG). There has been increasing interest in powering vehicles using green energy include using electricity produced by wind turbine and solar panel. The green electricity can be used to directly charge the Battery Electric Vehicles (BEV), or producing hydrogen as fuel for Fuel Cell Electric Vehicles (FCEV) by converting electrical energy to hydrogen (H₂) through water electrolysis. The low energy density H₂ produced can be stored on board as either compressed H₂ or liquefied H₂.

This research examines the …

Metaheuristics For The Generalized Quadratic Assignment Problem, Roseline Mostafa

Graduate Theses, Dissertations, and Problem Reports (ETD)

The generalized quadratic assignment problem (GQAP) is the task of assigning a set of facilities to a set of locations such that the sum of the assignment and transportation costs is minimized. The facilities may have different space requirements, and the locations may have varying space capacities. Also, multiple facilities may be assigned to each location such that space capacity is not exceeded. In this research, an application of the GQAP is presented for assigning a set of machines to a set of locations on the plant floor. Two meta-heuristics are proposed for solving the GQAP: tabu search (TS) and …

Analysis Of Factors Influencing The Stationarity Of Surface Electromyography Signals Measured In Non-Fatigued Shoulder Muscles, Hui Ci

Graduate Theses, Dissertations, and Problem Reports (ETD)

A reduction in the % stationarity of surface electromyography (SEMG) signals with respect to the initial or fresh condition is used to predict localized muscle fatigue. However, factors other than muscle fatigue can also influence the stationarity of SEMG signals. This study was aimed at analyzing the effect of various work/task related factors on the stationarity of SEMG signals obtained from non-fatigued shoulder muscles. Twelve participants were recruited for data collection and each one performed 120 trials characterized by the combination of 2 shoulder angles (60° and 120°), 2 planes of exertions (sagittal and scapular), 3 force levels (0lb, 2.5lb, …

Sustainability-Based Expert System For Additive Manufacturing And Cnc Machining, Josage Chathura Pamuditha Perera

Graduate Theses, Dissertations, and Problem Reports (ETD)

The development of technologies which enable resource efficient production is of paramount importance for the continued advancement of the manufacturing industry. In order to ensure a sustainable and clean energy future, manufacturers should be able to contrast and validate existing manufacturing technologies on a sustainability basis. In the post COVID-19 era of enterprise management, the use of artificial intelligence to simulate human expert decision making abilities will open new doors to achieving heightened levels of productivity and efficiency. The introduction of innovative technologies such as CNC machining and 3D printing to production systems has redefined the manufacturing landscape in a …

Evaluation Of Control Strategies For Overhead Work Using Electromyography Of Rotator Cuff Muscles, Hossein Motabar

Graduate Theses, Dissertations, and Problem Reports (ETD)

Work-related musculoskeletal disorders (MSDs) of shoulder have a significant impact on overall health and economics in the industrialized nations. Rotator cuff is the most frequently injured region in the shoulder complex. Overhead work is considered as one of the most predominant causes of rotator cuff injuries. The workers in construction, automotive, and aerospace industries are routinely exposed to overhead exertions. Elimination of overhead work is nearly impossible due to various task and technology constraints. Therefore, appropriate intervention strategies based on the engineering and administrative controls opt to be used to prevent the hazardous impact of overhead exertions. The objective of …

Next Generation Of Applications Of Metal-Organic Frameworks For Energy And Environmental Sustainability, Qian Liu

Graduate Theses, Dissertations, and Problem Reports (ETD)

My PhD work aimed at using Metal-organic frameworks (MOFs) for mitigating the environmental issues and energy crisis associated with anthropogenic activities. Specifically, we developed robust platforms and/ or systems using MOF as “scaffolds” to allow for model pollutant detection and CO₂ sequestration and benign transformation respectively.

First, I detailed how photocatalytic properties of 2,5-furandicarbocylic acid (FDCA) in its alone and its MOF- integrated form (MIL-160) were used for the first time for the reduction of Ag⁺ at room conditions. Such photocatalytic activities could then be used in user-designed hybrids (i.e., Ag/MIL-160) to form sensorial platforms for prevalent phenol …

Review Of Established And Emergent Methods For The Production Of C4 Olefins, James Matthew Koval

Graduate Theses, Dissertations, and Problem Reports (ETD)

Current production of C₄ olefins is dominated by naphtha cracking and butane dehydrogenation, but significant research interest is developing in alternate feedstocks due to an abundance of inexpensive natural gas and bioethanol. The current C₄ olefin production methods are costly, make use of already-depleted petroleum resources, and are often hazardous to workers, which forms the impetus for investigation into alternative methods and assessment of their viability as a future means of olefin production. Methods of natural gas conversion to higher order hydrocarbons are discussed, including Fischer-Tropsch synthesis and oxidative methane coupling, each of which could form the first …

Parametric Optimization Of Visible Wavelength Gold Lattice Geometries For Improved Plasmon-Enhanced Fluorescence Spectroscopy, Casey A. Norville

Graduate Theses, Dissertations, and Problem Reports (ETD)

The exploitation of spectro-plasmonics will allow for innovations in optical instrumentation development and the realization of more efficient optical biodetection components. Biosensors have been shown to improve the overall quality of life through real-time detection of various antibody-antigen reactions, biomarkers, infectious diseases, pathogens, toxins, viruses, etc. has led to increased interest in the research and development of these devices. Further advancements in modern biosensor development will be realized through novel electrochemical, electromechanical, bioelectrical, and/or optical transduction methods aimed at reducing the size, cost, and limit of detection (LOD) of these sensor systems. One such method of optical transduction involves the …

Comparative Assessment Of Different Ultra-Low Nox Measurement Instruments For Heavy-Duty Diesel Engines, Diego Bernabe Mejia

Graduate Theses, Dissertations, and Problem Reports (ETD)

Constant Volume Sampling (CVS) systems are an approved method for emission testing as stated in CFR Title 40 Part 1065 Engine Emission Testing Program. For future near zero emission vehicles, the emission measurement equipment must verify the results with the same accuracy as the limits in the past. The most critical values are the limitations for THC, NO_x and particulate matter.

The objective of this study was aimed at identifying challenges associated with measuring system-out emissions at proposed ultra-low NO_x (ULNO_x) levels - 0.02 (g/bhp-hr) and system robustness. The study compared a variety of existing instrument …