Mechanical Engineering Commons^™

Utility-Scale Solar Pv Performance Enhancements Through System Level Modifications, Andrew D. S. Glick, Naseem Ali, Juliaan Bossuyt, Marc Calaf, Raúl Bayoán Cal

Mechanical and Materials Engineering Faculty Publications and Presentations

Performance of solar PV diminishes with the increase in temperature of the solar modules. Therefore, to further facilitate the reduction in cost of photovoltaic energy, new approaches to limit module temperature increase in natural ambient conditions should be explored. Thus far only approaches based at the individual panel level have been investigated, while the more complex, systems approach remains unexplored. Here, we perform the first wind tunnel scaled solar farm experiments to investigate the potential for temperature reduction through system-level flow enhancement. The percentage of solar irradiance converted into electric power depends upon module efficiency, typically less than 20%. The …

Agile Stage-Gate Management (Asgm) For Physical Products, John J. Salvato, Andre O. Laplume

Michigan Tech Publications, Part 1

We present a qualitative study of Agile Stage-Gate Management (ASGM),: a hybrid new product development methodology that combines Agile and Stage-Gate Management (SGM) approaches for the coordination of new product development. When applied to software projects, Agile is expected to deliver reduced development times, improved resource utilization, and greater financial success. We examine whether ASGM practitioners realize similar outcomes in a sample of global firms developing complex electro-mechanical products (e.g., automobile components, railway propulsion systems, and medical devices). Our grounded theory approach articulates an understanding of ASGM through extensive interviews of experienced professionals. Our thematic analysis supports many expected benefits …

Towards Large Eddy Simulation Of A Staged, Pressurized Oxy-Fuel Combustor, Alain Islas Montero

Graduate Theses, Dissertations, and Problem Reports (ETD)

Identified by the DoE among the novel and transformational technologies, staged-pressurized oxy-fuel combustion (SPOC) is a promising low-cost, low-emission, and highly efficient tool for carbon capture utilization and storage (CCUS), with pulverized coal burning under elevated pressures and low recycled flue gas. A lab-scale SPOC facility, under establishment at Washington University in St. Louis (WUSTL), causes the critical need to develop accurate and reliable computational models to assist the ongoing WUSTL experiments. This constitutes the driving motivation of the present work. Specifically, comprehensive three-dimensional Large-eddy simulations (LES) of the lab-scale SPOC reactor, with most of important characteristics of a multi-phase …

Automated And Standardized Tools For Realistic, Generic Musculoskeletal Model Development, Trevor Rees Moon

Graduate Theses, Dissertations, and Problem Reports (ETD)

Human movement is an instinctive yet challenging task that involves complex interactions between the neuromusculoskeletal system and its interaction with the surrounding environment. One key obstacle in the understanding of human locomotion is the availability and validity of experimental data or computational models. Corresponding measurements describing the relationships of the nervous and musculoskeletal systems and their dynamics are highly variable. Likewise, computational models and musculoskeletal models in particular are vitally dependent on these measurements to define model behavior and mechanics. These measurements are often sparse and disparate due to unsystematic data collection containing variable methodologies and reporting conventions. To date, …

Route Planning For Long-Term Robotics Missions, Christopher Alexander Arend Tatsch

Graduate Theses, Dissertations, and Problem Reports (ETD)

Many future robotic applications such as the operation in large uncertain environment depend on a more autonomous robot. The robotics long term autonomy presents challenges on how to plan and schedule goal locations across multiple days of mission duration. This is an NP-hard problem that is infeasible to solve for an optimal solution due to the large number of vertices to visit. In some cases the robot hardware constraints also adds the requirement to return to a charging station multiple times in a long term mission. The uncertainties in the robot model and environment require the robot planner to account …

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 …

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 …

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 …

Doping With Rare Earth Elements And Resultant Nano-Inclusions On The Electrical And Thermal Properties Of The Mis-Fit Layered Thermoelectric Oxide, Geoffroy Gauneau

Graduate Theses, Dissertations, and Problem Reports (ETD)

Thermoelectric generators produce electricity by directly converting temperature differences into electrical energy through Seebeck effect. Thermoelectric generators possess many unique features, such as having no moving part and being very reliable with a relatively long lifespan once built. They are solid-state waste heat harvesters. With various waste heat available throughout many industries, thermoelectric generators could offer economically competitive renewable energy. The current state of the art thermoelectric materials includes materials with relatively toxic elements and must work under vacuum, making them quite expensive to produce. Among the various thermoelectric materials, ceramic oxides have been proved to be more chemically stable …

Effects Of Supplementary Cementitious Materials On Early-Age Tensile Creep And Shrinkage Of Concrete, Lucas James Bucklen

Graduate Theses, Dissertations, and Problem Reports (ETD)

Determination of early-age tensile creep properties is critical for the performance of mass concrete structures at an early age. Due to the stress relaxation that tensile creep induces in concrete structures, accurate quantification of creep deformation is needed to determine the stress profile of the structure. Conventional methods of measuring tensile creep include the direct tension test where the concrete is subject to constant tensile stress. This method requires large quantities of concrete with embedded strain gauges which can only be used once. In this paper, the tensile creep parameters of concrete are found by using the restrained concrete ring …

A Study On The Hydrodynamics Of A Bench-Scale Top-Fed Bubbling Fluidized Bed Gasifier Using Biomass And Coal As Feedstocks, Ali Can Sivri

Graduate Theses, Dissertations, and Problem Reports (ETD)

The production of synthetic gas (syngas) from renewable or carbon-neutral sources can significantly reduce greenhouse and other emissions associated with conventional fuels. One of the most promising technologies to efficiently convert carbonaceous feedstocks such as biomass, coal, or municipal waste into syngas for transportation, power, heat, electricity generation, and or production of added-value chemicals is the bubbling fluidized-bed gasifier (BFBG). However, the gasification process inside a BFBG is a very complex high-temperature multiphase flow phenomena still not well understood, particularly when binary mixtures are investigated. As a result, despite the numerous correlations in the literature developed to predict the hydrodynamics …

Design And Optimization Of Dynamic System For A One-Kw Free Piston Linear Engine Alternator-Gensets Program, Nima Zamani Meymian

Graduate Theses, Dissertations, and Problem Reports (ETD)

In power/energy systems, free-piston linear machines are referred to as a mechanism where the constrained crank motion is eliminated and replaced with free reciprocating piston motion. Depending on the application, the piston motion can be converted into other types of energy and includes compressed air/fluid, electricity, and high temperature/pressure gas. A research group at West Virginia University developed a free-piston linear engine alternator (LEA) in 1998 and have achieved significant accomplishment in the performance enhancement of the LEAs to date. The present LEA design incorporates flexure springs as energy restoration components and as bearing supports. The advantages of using flexure …

Characterizing Premixed Syngas Combustion In Micro-Channels, Sunita Pokharel

Graduate Theses, Dissertations, and Problem Reports (ETD)

Increasing demands in the next-generation portable power-generation devices such as unmanned aerial vehicles (UAV), microsatellite thrusters, micro-chemical reactors and sensors calls for fuels with high specific energy and low emissions to meet the current demand of green energy. Fuel-lean synthesis gas (syngas) meets both these requirements exhibiting a promising route to a clean and green environment. Thus, it is of critical importance to characterize syngas combustion and understand its properties in the micro-combustion industry. In addition to complicated flame dynamics in microscale systems, varying the syngas-fuel mixture composition as well as the boundary conditions and geometry of a combustor significantly …

Modeling And Tuning Of Cvt Systems For Sae® Baja Vehicles, Sean Sebastian Skinner

Graduate Theses, Dissertations, and Problem Reports (ETD)

Continuously variable transmission (CVT) describes a family of transmission styles. These systems serve the same purpose as their traditional counterparts; transmitting power while offering a variable gearing ratio. The difference lies in the CVT’s ability to change ratio continuously between a minimum and maximum without halting power transfer. They offer many benefits of an automatic transmission while being significantly lighter. For this reason, CVTs are often used on Baja SAE^® vehicles to control gearing ratio.

WVU’s Baja team has used mechanical CVTs for many decades. These systems are simpler in the sense that they don’t require power to operate. …

Experimental, Computational And Analytical Studies Towards A Predictive Scenario For A Burning Accident, Furkan Kodakoglu

Graduate Theses, Dissertations, and Problem Reports (ETD)

Historically, accidental gas and dust explosions constitute one of the major hazards to both personnel and equipment in the process industries. The current knowledgebase on such explosions does not provide an acceptable level of risk. Therefore, novel preventive mining/fire safety strategies, based on a rigorous predictive scenario for burning accidents, are critically needed. The present dissertation is devoted to such a predictive scenario, with a particular focus on the flame and pressure evolutions in explosions encountered in an enclosure with or without obstructions. The experimental component of this dissertation comprises a series of experiments on explosion venting. Specifically, the influence …

Impact Of Particle Injection On Gas Flow At Elevated Pressure: A Numerical Study, Ansan Pokharel

Graduate Theses, Dissertations, and Problem Reports (ETD)

Modeling of a turbulent two-phase gaseous-solid flow still faces challenges. The present study is devoted to two-phase flow in an annular pipe (hollow cylinder) operating at an elevated pressure of 15 bar and moderate Reynolds numbers of circa 6 x 10³. The influence of the various factors – such as the particle loading, the interaction between the phases, and turbulent dispersion – on the flow dynamics is systematically studied by means of the computational simulation employing the ANSYS FLUENT commercial package. To be specific, particle loading with a volumetric fraction of 1.2 % is defined as high particle …

Development Of An Activity-Based Windowing Approach To Evaluate Real-World Nox Emissions From Modern Medium And Heavy-Duty Diesel Trucks, Rasik Pondicherry

Graduate Theses, Dissertations, and Problem Reports (ETD)

The introduction of in-use emissions regulations by the United States Environmental Protection Agency (U.S.EPA) requires medium-duty (MD) and heavy-duty (HD) engine manufacturers to demonstrate emissions compliance during in-fleet operation. In the United States (U.S.), the Not-to-Exceed (NTE) method is used to evaluate real-world emissions compliance from on-highway MD and HD trucks. Regulatory agencies, engine manufacturers and research entities have identified that the NTE method incorporates numerous exclusions and evaluates emissions compliance only under selective operating conditions that are favorable for the selective catalytic reduction (SCR) system to reduce oxides of nitrogen (NOx) emissions efficiently. Such operation is typically encountered only …

Evaluation Of Process And Economic Feasibility Of Implementing A Topping Cycle Cogeneration System, Unique Karki

Graduate Theses, Dissertations, and Problem Reports (ETD)

Industrial applications that require steam for their end-uses generally utilize steam boilers that are at higher size than what is typically required. Similarly, gas turbine-based power plants corroborate the gas turbine system and eventually relieve the exhaust into the atmosphere. These facilities include food, paper, chemicals, refining, and primary metal manufacturing industries. This research focuses on the scope of a topping cycle combined heat and power (CHP) system by pushing the load on the boiler to a higher limit, or a gas turbine operation in place of a boiler system for a topping cycle CHP and its economic feasibility by …

Analysis Of Mechanical Deformation Eect On The Voltage Generation Of A Vertical Contact Mode Triboelectric Generator, Nabid Aunjum Hossain, Mir Jalil Razavi, Shahrzad Towfighian

Mechanical Engineering Faculty Scholarship

One of the associated factors that controls the performance of a triboelectric generator (TEG) is the mechanical deformation of the dielectric layer. Therefore, a good contact model can be a prominent tool to find a more realistic and efficient way of determining the relationships between the contact and electrical output of the generator. In this study, experiments are conducted on a vertical contact mode triboelectric generator under an MTS machine. The open-circuit voltages are measured at different loads imposed by the MTS by controlling the cyclic displacement of the top tribo layer of the generator. A finite-element-based theoretical model is …

Modeling And Characterization Of A Pull-In Free Mems Microphone, Mehmet Ozdogan, Shahrzad Towfighian, Ronald Miles

Mechanical Engineering Faculty Scholarship

In this study, we examine the feasibility of designing a MEMS microphone employing a levitation based electrode configuration. This electrode scheme enables capacitive MEMS sensors that could work for large bias voltages without pullin failure. Our experiments and simulations indicate that it is possible to create robust sensors properly working at high DC voltages, which is not feasible for most of the conventional parallel plate electrode-based micro-scale devices. In addition, the use of larger bias voltages will improve signal-to-noise ratios in MEMS sensors because it increases the signal relative to the noise in read-out circuits. This study presents the design, …

Lateral Pull-In Instability Of Electrostatic Mems Transducers Employing Repulsive Force, Meysam Daeichin, Ronald Miles, Shahrzad Towfighian

Mechanical Engineering Faculty Scholarship

We report on the lateral pull-in in capacitive MEMS transducers that employ a repulsive electrostatic force. The moving element in this system undergoes motion in two dimensions. A two degree-offreedom mathematical model is developed to investigate the pull-in quantitatively. The nonlinear electrostatic force, which is a vector function of two spatial coordinates, is determined by calculating the potential energy of the system using a boundary element approach. The equilibrium points are found by numerically solving the nonlinear coupled static equations. A stability analysis reveals that depending on the values of the lateral and transverse stiness, the system undergoes dierent bifurcations …

An Extensive Set Of Kinematic And Kinetic Data For Individuals With Intact Limbs And Transfemoral Prosthesis Users, Seyed Abolfazl Fakoorian, Arash Roshanineshat, Poya Khalaf, Vahid Azimi, Daniel J. Simon, Elizabeth Hardin

Electrical and Computer Engineering Faculty Publications

This paper introduces an extensive human motion data set for typical activities of daily living. These data are crucial for the design and control of prosthetic devices for transfemoral prosthesis users. This data set was collected from seven individuals, including five individuals with intact limbs and two transfemoral prosthesis users. These data include the following types of movements: (1) walking at three different speeds; (2) walking up and down a 5-degree ramp; (3) stepping up and down; (4) sitting down and standing up. We provide full-body marker trajectories and ground reaction forces (GRFs) as well as joint angles, joint velocities, …

Buckling Load Study On Pop Nut (Rivet) Using Finite Element Analysis, Saurabh Shankar Shegokar

Dissertations, Master's Theses and Master's Reports

This study highlights the material behavior in riveting operation that includes buckling load analysis using ABAQUS. Finite Element Analysis is used to find the buckling load vs. Displacement results and validated with the results obtained in physical testing of rivet (POP Nut). A mesh sensitivity study is performed using ABAQUS to understand the optimum mesh size for this analysis. An axisymmetric model with contact properties is created and simulated to reduce the simulation time using ABAQUS. The results obtained through Finite Element Analysis show a good resemblance with the testing results. Design changes were suggested to achieve better results that …

Radio Frequency Studies Of Soot Loading And Ammonia Storage On A Diesel Particulate Filter With A Scr Catalyst Coating, Shreyans Sethia

Dissertations, Master's Theses and Master's Reports

The radio frequency (RF) measurement technique has been shown to be a viable method for measurement of the amount of soot loaded onto DPF’s ^[1] and the amount of NH₃ stored on SCR catalysts ^[2]. In one of the configurations, a microwave resonant cavity is formed by the metal can encasing the enclosed catalyst. Two metal probes acting as antennas are placed on either side of the catalyst. Power transmitted between the antennas is monitored as the frequency of the signal is swept. At certain frequencies, resonance is achieved. Measurements of the resonance frequencies, amplitude at resonance, and …

Comparative Evaluation Of Carbon Reinforced Polyetherketone Acetabular Cup Using Finite Element Analysis, A. Abdal, Rafiqul Noorani, G. Cha

Mechanical Engineering Faculty Works

Background: Patients suffering from osteoarthritis undergo surgery to replace hip joints with hip prosthesis implants. Today most acetabular cups of hip prostheses are made of Ultra-High-Molecular-Weight-Polyethylene. However, these materials acting as acetabular cups of the implant have been recalled since patients have been feeling uncomfortable and abstained from physical activities. A newly introduced material, 30% Carbon Reinforced Polyetherketone, possess better isotropic mechanical properties and lower wear rates.

Objective: The research aims to compare the von-Mises stresses and deformation in static and dynamic loading of Ultra-High Molecular-Weight-Polyethylene to 30% Reinforced Carbon Fiber Polyetherketone using Finite Element Analysis.

Material and Methods: An …

Experimental And Computational Characterization Of Sodium Nitrate @ Silica Nano Capsules For Thermal Energy Storage Applications, Wataru Hashimoto

Graduate Research Theses & Dissertations

In this investigation, a nanocapsule composed of a sodium nitrate core and a silicon dioxide shell is synthesized, characterized, and analyzed utilizing a mixture of analytical and computational tools. The sol-gel method was selected as the process of nanoencapsulation. Analytical characterization techniques employed in this investigation include differential scanning calorimetry (DSC) to measure melting temperatures and enthalpies of fusion, dynamic light scattering (DLS) to calculate particle size distributions, scanning electron microscopy (SEM) to analyze surface characteristics, transmission electron microscopy (TEM) to perform shell characterization, and energy dispersive X-ray spectroscopy (EDS) to determine chemical composition. Preliminary results indicated a decrease in …

Transportation Analysis And Related Design Optimization Of The Fermilab High-Beta 650 Mhz Cryomodule, Josh F. Helsper

Graduate Research Theses & Dissertations

The Proton Improvement Plan-II (PIP-II) at Fermi National Accelerator Laboratory(FNAL) will create a new and vastly improved accelerator, which will be the source of high energy particles for the experiments taking place at FNAL. The new linear accelerator (LINAC) contains several types of cryomodules, which are individual particle accelerators. The last cryomodule in the LINAC will be the High-Beta 650 (HB650), which will operate at 650 MHz. Each module is approximately 15 meters in length, 1.5 meters wide, weighs 13 tonnes, and shares many design features with three of the other cryomodules. The HB650 consists of two primary sections, the …

Laminate-Like Behavior Of An Additively Manufactured Polymer With Underlying Bioinspired Architecture, Flavio Jonuzaj

Graduate Research Theses & Dissertations

Laminates are a class of composite materials in which several unidirectional laminae are stacked together to create a material with a clear layer-by-layer architecture. Traditionally, each lamina is itself a composite consisting of aligned fibers, such as cellulose, graphite, or glass, embedded within a polymer, ceramic, or metal host matrix. These materials are unique in the sense that their engineering properties can be greatly varied simply by changing the stacking order of lamina within the laminate. While there are several traditional manufacturing approaches for laminates, recent research has focused on assessing the feasibility of using additive manufacturing techniques to create …

Micro-Macro Mathematical Modeling Analysis Of An Al-Air Battery, Christopher Charles Welch

Graduate Research Theses & Dissertations

The aluminum-air battery is a very promising electrical energy storage system for portable electronics and electric vehicles because it is safe, inexpensive, and has a very high energy density. With the [EMIm]Cl-AlCl3 room-temperature ionic liquid (RTIL) electrolyte, by controlling the acidity, H2 evolution and dendrite formation are prevented and the Al2O3 passive film on the anode can be partially dissolved (cracked), so the battery’s lifespan is extended and even allows battery charging. Still, the Al2O3 passive film on the anode and Al2O3 deposition on the cathode remain issues which negatively affect battery performance. While these phenomena have been experimentally observed, …

Implementation Of A 2d Bond Based Peridynamic Fatigue Model In Fem, Kyle Mansfield

Graduate Research Theses & Dissertations

A relatively new fracture theory known as peridynamics has been developed which uses a nonlocal theory to describe crack growth, resolving many of the issues associated to the classical continuum theory. Internal material interactions are described via a family of ‘bonds’, capable of exerting force over a macro-scale region of influence known as the horizon. Bond damage accumulates naturally due to repeated cyclic or critical loading and damage precipitates as a growing crack as bonds reach a critical damage and are severed. In the present work a modified compact tension specimen subjected to cyclic loading is modeled with the 2D …