Mechanical Engineering Commons^™

Numerical Study Of Flow Of Supercritical Carbon Dioxide Inside Microchannels With Heat Transfer, Uday Manda

Electronic Theses and Dissertations, 2020-2023

Heat transfer inside microscale geometries is a complex and a challenging phenomenon. As supercritical fluids display large variations in their properties in the vicinity of the critical point, their usage could be more beneficial than traditional coolants. This numerical study, in two parts, primarily focuses on the physics that drives the enhanced heat transfer characteristics of carbon dioxide (CO2) near its critical state and in its supercritical state. In the first part of the study, the flow of supercritical Carbon Dioxide (sCO2) over a heated surface inside a microchannel of hydraulic diameter 0.3 mm was studied using three-dimensional computational fluid …

Decentralized Digital Fabrication Of Flexible Micro/Nano Devices Using A Laserjet Printer, Arshya Bamshad

Electronic Theses and Dissertations, 2020-2023

The fabrication of traditional micro/nano devices requires access to cleanrooms, complex and expensive tools, and highly-skilled labor. A facile and digital do-it-yourself (DIY) technique for the fabrication of low-cost devices on flexible substrates (paper, cloth, and plastic films) is presented in this work. A set of office-grade equipment (i.e., laserjet printer, thermal laminator, computer-aided paper cutter), and commercially available supplies (i.e., baking wax paper, furniture restoration metal-leaf) are utilized. The presented technology enables community-embedded production by removing a high technological barrier. The validity of the proposed technology was proved by designing three levels of experiments, i.e., patterns, devices, and systems. …

An Innovative Elastohydrodynamic Seal Concept For Gases, Matthew J. Demond

College of Graduate Studies: Theses & Dissertations

Supercritical CO₂ (sCO₂) power cycles are next generation power technologies offering improved efficiency, lower customer costs, and less water usage. They hold significant potential in many different industries such as nuclear power production, ship propulsion, geothermal power, solar power, and fossil fuel power plants. One of the largest hurdles preventing this milestone is the lack of suitable shaft seals for sCO₂ operating conditions. This component issue needs to be addressed for the next generation nuclear turbine and compressor development to progress. In this study, a novel Elastohydrodynamic (EHD) seal is proposed. This proposed design is capable …

Determining Cause Of Failure For Load Cells Supporting Vertical Pressure Vessels Subject To Wind Loading, Seth Nowak

College of Graduate Studies: Theses & Dissertations

Wind loads cannot be avoided during a natural disaster such as a hurricane and could affect the strength and stability of vertical pressure vessels during exposure. Vertical pressure vessels cater to large wind loads; therefore, it is imperative to study the effect of additional loading on the structures. In this study, three pressure vessels with volumes of 50 CuFt, 200 CuFt, and 1100 CuFt, supported by three equidistant load cells under their legs are individually analyzed to determine von mises stress to estimate yield failure criteria. Two load rating criteria, maximum load capacity and water-filled condition (critical condition) are utilized …

An Analysis Of Thermal Comfort Perception In Cal Poly's Math & Science Building, Pouria Ali Fariborzi

Master's Theses

Since Americans, on average, spend approximately 90% of their time indoors according to the EPA, it is crucial to provide room occupants with the best, most comfortable, and healthiest possible environment, which is known as Indoor Environmental Quality (IEQ). This thesis aims to identify how we can provide comfortable learning environments to improve student success. To determine the best possible environment for occupants, a model of the Math & Science Building was developed, validated, and modified using DesignBuilder. In addition, we compared thermal comfort surveys to actual measured conditions for some classrooms. Analysis indicates that students prefer a cooler thermal …

Process Optimization For An Integrated Reverse Osmosis—Pressure Retarded Osmosis Pilot-Scale System Operated On Humboldt Bay, Ca, Galen O'Toole

Cal Poly Humboldt theses and projects

Pressure retarded osmosis (PRO) is an emerging osmotic power technology that could mitigate the major challenges faced by seawater reverse osmosis desalination (RO): brine disposal and high energy consumption. The primary focus of this paper is process optimization for a linked seawater reverse osmosis (RO) and pressure retarded osmosis (PRO) water purification system. PRO generates power by using osmosis to “pump” water through a membrane from low pressure and low concentration to high pressure and high concentration (RO brine). This commercial-scale pilot effort explores process optimization for pressure retarded osmosis as an industrial process rather than theoretical or experimental process. …

Recent Advances In Biosensors For Detection Of Covid-19 And Other Viruses, Shobhit K. Patel, Jaymit Surve, Juveriya Parmar, Kawsar Ahmed, Francis M. Bui, Fahad Ahmed Al-Zahrani

Department of Mechanical and Materials Engineering: Faculty Publications

This century has introduced very deadly, dangerous, and infectious diseases to humankind such as the influenza virus, Ebola virus, Zika virus, and the most infectious SARS-CoV-2 commonly known as COVID-19 and have caused epidemics and pandemics across the globe. For some of these diseases, proper medications, and vaccinations are missing and the early detection of these viruses will be critical to saving the patients. And even the vaccines are available for COVID-19, the new variants of COVID-19 such as Delta, and Omicron are spreading at large. The available virus detection techniques take a long time, are costly, and complex and …

The Toyota Production System (Tps) In A Non-Traditional Manufacturing Environment: The Role Of Standardization In The Fast-Food Industry, Kevin Mccracken

Theses and Dissertations--Manufacturing Systems Engineering

The Toyota Production System (TPS), also known as Lean Manufacturing (LM), was founded in the automotive industry and has contributed to Toyota’s decades of success. This has brought much attention to TPS and how this system may be implemented in other industries. Focusing on the TPS foundational element of standardization, this study examines the impact of target cycle time (TCT) on process fluctuation in a fast-food environment. In order to observe the effects of TCT, team members within 3 production lines were timed. Times were measured before and after the addition of a TCT to the Standardized Work (STW) in …

Airflow Impact Upon Remote Laser Welding Quality, Baixuan Yang

Mechanical Engineering Research Theses and Dissertations

Laser induced plasma-plume and condensed particles attenuate the laser beam energy, resulting in keyhole instability and lacking penetration. There are various airflow devices that are currently used in both industrial and laboratory laser welding settings to suppress the detrimental effect of plasma plume and hot spatters. A systematic experimental and numerical study is presented in this dissertation that investigates different external airflow effects on the remote laser welding process used in automotive manufacturing applications.

The vertical airflow impact on the remote laser welding was first studied experimentally. The airflow velocity profiles of a coaxial vertical flow device were measured using …

An Experimental Study Of Fuel Selection For A Gasoline Multi-Mode, Spark Ignited – Compression Ignition Engine, Zachary J. Stanchina

Dissertations, Master's Theses and Master's Reports

In this study of fuels of different reactivities and their performance in a low-temperature combustion (LTC) engine. The engine was a 2.2L CRDI engine code D4HB provided by industry partner Hyundai America Technical Center inc. (HATCI). The engine was instrumented with in-cylinder pressure sensors allowing for monitoring of the combustion process.

First, the engine was operated with standard US pump grade gasoline, Research Octane number (RON) 91 E10, to find initial operation conditions as well as control points of stable operation for daily checks on system conditions.

Tested were 8 different fuel blends, the four base blends were provided by …

Incorporating High-Fidelity Aerostructural Analyses In Wind Turbine Rotor Optimization, Denis-Gabriel Caprace, Adam Cardoza, Andrew Ning, Marco Mangano, Sicheng He, Joaquim R. R. A. Martins

Faculty Publications

s demand grows for wind turbines with larger blades, the design of future wind turbines must account for multi-physical interactions and an ever-increasing number of design load conditions. One aspect, aerostructural coupling, calls for design tools that are both accurate and computationally efficient. In this paper, we present a combined-fidelity approach that couples high-fidelity computational fluid dynamics and computational solid mechanics simulations, with a conventional aeroelastic turbine modeling tool based on blade element momentum and beam theories. The approach is integrated into a multidisciplinary optimization framework. It takes advantage of the high-fidelity tightly-coupled aerostructural simulations to evaluate the rotor power …

Antagonistic Co-Contraction Can Minimize Muscular Effort In Systems With Uncertainty, Anne D. Koelewijn, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Muscular co-contraction of antagonistic muscle pairs is often observed in human movement, but it is considered inefficient and it can currently not be predicted in
simulations where muscular effort or metabolic energy are minimized. Here, we investigated the relationship between minimizing effort and muscular co-contraction
in systems with random uncertainty to see if muscular co-contraction can minimize effort in such system. We also investigated the effect of time delay in the muscle, by varying the time delay in the neural control as well as the activation time constant.We solved optimal control problems for a one-degree-of-freedom pendulum actuated by two identical …

Nanomechanical Characterization And Comparison Of Additively Manufactured Grcop-42 Alloy, Trupti Suresh Mali

Electronic Theses and Dissertations

In an aggressive thermomechanical environment, the superior mechanical as well as thermal properties of materials play an essential role. GRCop which is a copper-based alloy developed by NASA has the potential to fulfill the requirements necessary for hightemperature applications such as the combustion chamber of liquid rocket engines. The first alloy of this family, GRCop-84 (Cu-8 wt.% Cr-4 wt.% Nb) was discovered followed with the development of GRCop-42 (Cu-4 wt.% Cr, 2 wt.% Nb). The reduction in alloying element percentage enhanced thermal conductivity with less built time while maintaining the strength of the material. The conventional fabrication is replaced with …

Design, Development, And Testing Of Near-Optimal Satellite Attitude Control Strategies, Giovanni Lavezzi

Electronic Theses and Dissertations

Advances in space technology and interest toward remote sensing mission have grown in the recent years, requiring the attitude control subsystems of observation satellites to increase their performances in terms of pointing accuracy and on-board implementability. Moreover, an increased interest in small satellite missions and the recent technological developments related to the CubeSats standard have drastically reduced the cost of producing and flying a satellite mission. In this context, the proposed research aims to improve the state of the art for satellite attitude control methodologies by proposing a near-optimal attitude control strategy, simulated in a high-fidelity environment. Two strategies are …

A Computational Fluid Dynamics Analysis Of The Temperature And Impurity Profiles In The Protodune-Sp Neutrino Detector, Jenna Harrison

Electronic Theses and Dissertations

Computational fluid dynamics (CFD) models of the ProtoDUNE single-phase detector were developed, refined, and analyzed. The ProtoDUNE single-phase detector is a prototype detector that is part of the Deep Underground Neutrino Experiment, an international research collaboration aimed at better understanding neutrinos and the role they play in our universe. The ProtoDUNE single-phase detector is used to gather data and inform design changes for the full-sized far detector prior to its construction. The effects of certain geometric features and heat sources on the thermal profiles within the liquid region of the detector were investigated in a set of parametric studies. The …

Project-Based Learning In Non-Traditional Settings In Engineering Education, Mary Foss

Electronic Theses and Dissertations

The purpose of this study is to examine the effectiveness of utilizing the principles of Project-based learning (PJBL) in nontraditional settings in engineering education. There is ample literature related to the usage of PJBL techniques in engineering education but there are also challenges with incorporating PJBL within the curriculum. It is the aim of this dissertation to build upon this understanding of the advantages and limitations of PJBL in engineering education and identify areas within the existing body of knowledge in which more research is needed. This dissertation divides this topic into 4 sub-topics. The first sub-topic explores how PJBL …

Spatial Transformation Of A Layer-To-Layer Control Model For Selective Laser Melting, Xin Wang, Robert G. Landers, Douglas A. Bristow

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Selective Laser Melting (SLM) is an Additive Manufacturing (AM) technique with challenges in its complexity of process parameters and lack of control schemes. Traditionally, people tried time-domain or frequency-domain control methods, but the complexity of the process goes beyond these methods. In this paper, a novel spatial transformation of SLM models is proposed, which transforms the time-domain process into a spatial domain model and, thus, allows for state-space layer-to-layer control methods. In a space domain, this also provides the convenience of modelling laser path changes. Finally, a layer-to-layer Iterative Learning Control (ILC) method is designed and demonstrates the methodology of …

High-Pressure Kinetic Interactions Between Co And H2 During Syngas Catalytic Combustion On Pdo, Ran Sui, John Mantzaras, Rolf Bombach, Meysam Khatoonabadi

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The catalytic combustion of H2/CO/O2/N2 mixtures over PdO was investigated at pressures 3 to 10 bar, H2:CO volumetric ratios 1:5 to 3:1, and global equivalence ratios ψ = 0.13 and 0.23. The catalyst surface temperatures were controlled to 540-690 K, a range especially important for hybrid hetero-/homogeneous combustion approaches with large gas turbines at idle or part-load operation and for microreactors with recuperative small-scale turbines. In situ Raman measurements determined the major gas-phase species concentrations over the catalyst boundary layers in a channel-flow reactor, thermocouples monitored the surface temperatures, and surface characterization identified the catalyst oxidation state (PdO) and surface …

Coastal Wave Powered Reverse Osmosis System, Alexander Raymond Charest, Joeseph Daniel Camobreco, Tori Sweet, Sam Williams, Andrew Lepage, Devan Sack, Meagan Wiggin, Chelsea Kimball, Brendan Reagan

Honors Theses and Capstones

Part of the Marine Energy Collegiate Competition (MECC) is the optional Build and Test Challenge where teams are encouraged to build a portion of their proposed solution. After the conducted testing the laboratory results are compared to the simulated and calculated models. For the MECC the University of New Hampshire (UNH) team decided to use a wave energy converter to produce pressurized water. The pressurized water would be filtered through a reverse osmosis membrane to make it potable. Our system uses the power of the ocean waves to move a float up and down in heave motion. This motion drives …

Tractor Test 2252: John Deere 9rx 540, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Tractor Test 2251: John Deere 9rx 490, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Tractor Test 2250: John Deere 9rt 570, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Tractor Test 2249: John Deere 9rt 520, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Tractor Test 2248: John Deere 9rt 470, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Test 2261: John Deere 6140m, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Test 2259: John Deere 9r 440, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Test 2257: John Deere 5125m, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Test 2256: John Deere 5115m, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Test 2255: John Deere 5100m, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Test 2254: John Deere 5090m, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …