Mechanical Engineering Commons^™

Heater Control For Thermionic Power Generation, Charlie Markusen, Patrick Kearney, Jaydon Zimmerman

Mechanical Engineering Senior Theses

The purpose of this report is to detail the conceptualization, analysis, budget, manufacturing, and assembly the heater for a thermionic energy converter for portable energy generation. This proof of concept will be created to provide a full thermionic energy converter with a reliable and satisfactory heater than can be used in future systems. The report highlights the feasibility and realities in the design and fabrication of the system.

Understanding The Strain Localization And Progressive Damage Growth At The Free-Edge Of Composite Laminates Using Digital Image Correlation, Addis Tessema

Theses and Dissertations

Understanding the mechanics of Fiber Reinforced Composites (FRC) that guide the design and optimization of laminate structures, have attracted numerous researchers. For the last five decades, various analytical and numerical models have been developed to understand the damage and failure mechanisms in FRC. For long, Classical laminate plate theory (CLPT) has majorly been used as a theoretical guide in the design of composite structures. The CLPT framework is developed based on the consideration of an infinitesimal wide plate that depicts a planar stress condition. Thus, as it considers only the planar stresses, the out of plane interlaminar stresses are absent …

Energy Analysis And Orbit Simulation Of Actuating Cubesat Solar Arrays, Justin T. Ehren

Honors Theses

CubeSats are used in space research to explore new technologies and detect data to gain a better understanding of various areas of research and subjects affecting human life. CubeSats rely on a solar array to generate energy from the sun and perform their various functions in space. This research studies the energy capturing potential of various solar array configurations and positioning devices for CubeSats. The location and orientation of a CubeSat is simulated with MATLAB for both geo-synchronous and sunsynchronous orbits. Two degree-of-freedom (DoF) positioning devices are sufficient to continuously adjust the photovoltaic array to face towards the sun. Lower …

Numerical Simulation Of Viscoelastic Flow In Micro/Nanochannels, Lanju Mei

Mechanical & Aerospace Engineering Theses & Dissertations

Micro/Nanofluidic devices often involve use of biological fluids or polymeric solutions that cannot be simply treated as Newtonian fluids. The numerical simulation for the complex fluids at micro/nanoscale presents a significant computational challenge, and the inclusion of electrokinetic body force further increases the complexity. Specifically, the well-known High Weissenberg Number Problem (HWNP) has become a challenge for the numerical simulation of viscoelastic fluid. This dissertation is aimed to develop a numerical tool to simulate the behavior of viscoelastic fluid in the micro/nanochannel. The most popular log-conformation reformulation to solve the HWNP is presented and implemented in a finite volume scheme. …

Off Axis Compressive Response Of Ice-Templated Ceramics, Rahul Kumar Jujjavarapu

Mechanical & Aerospace Engineering Theses & Dissertations

The off-axis compressive behavior of ice-templated ceramic was analyzed using experimental results and micro-mechanical model simulation. Ice-templated ceramics is a versatile processing technique used to manufacture anisotropic ceramic foam by exploiting the anisotropic growth characteristics and lamellar morphology. The ice-templating process results in processing-structure-property relationships determined by the microstructure. The processed alumina samples which were later manufactured by water jet machine from the freeze casting were tested under quasi-static off-axis loading conditions and were used to determine the mechanical properties of the material. Digital image correlation (DIC) was used to measure the strain response of ice-templated ceramic under off-axis loading. …

Comparison Of Support Methods For Static Aerodynamic Testing And Validation Of A Magnetic Suspension And Balance System, Cameron K. Neill

Mechanical & Aerospace Engineering Theses & Dissertations

Magnetic suspension wind tunnels offer an alternative to traditional physical support methods. They allow for the collection of support interference free data and broader dynamic test capabilities than existing methods. Determination of dynamic aerodynamic characteristics is a crucial portion of the design of new re-entry capsules. A NASA initiative restored the 6-inch Magnetic Suspension and Balance System to support the design of a new MSBS for a supersonic wind tunnel. Before a new MSBS can be constructed, the characteristics of the current MSBS must be examined.

This thesis discusses the calibration and validation of the 6-inch MSBS. After calibration, three …

Estimation Of Arterial Wall Parameters Via Model-Based Analysis Of Noninvasively Measured Arterial Pulse Signals, Dan Wang

Mechanical & Aerospace Engineering Theses & Dissertations

This dissertation presents a model-based method for estimating arterial wall parameters from noninvasively measured arterial pulse signals via a microfluidic-based tactile sensor. The sensor entails a polydimethylsiloxane (PDMS) microstructure embedded with 5×1 transducer array built on Pyrex/Polyethylene terephthalate (PET) substrate. The arterial pulse causes a time-varying deflection on the top of the PDMS microstructure, which registers as a resistance change by the transducer at the site of the artery.

Owing to the time-harmonic nature of its radial motion, the arterial wall is modeled as a second-order dynamic system. By combining this dynamic model with a hemodynamic model of blood flow, …

Wavelet Transform On Digital Rainbow Hologram Based On Spectral Compression For Quality Enhancement In 3d Display Media, Ucuk Darusalam, Panca Dewi Pamungkasari

Makara Journal of Technology

A digital rainbow hologram (DRH) is a potential next-generation three-dimensional display media for the development of modern and smart electronics devices. It is one of the methods that can support the characteristic whereby a realistic display media occupies the space that the real object would have occupied. Since a rainbow hologram records a large amount of spatial or temporal frequency component from the object that represents the rainbow spectrum, a large amount of information needs to be decoded digitally. In this paper, to reconstruct a DRH, we propose a novel method based on the modulation of red, green, and blue …

Shock Compaction Of Graphene Doped Yttria Stabilized Zirconia: An Experimental And Computational Study, Christopher Rueben Johnson

Master's Theses (2009 -)

Yttria stabilized zirconia (YSZ) is a broadly used ceramic due to its impeccable hardness and thermal stability. Limitations of the material, however, subsist within its fracture toughness. Literature indicates that shock consolidation may enable production of composite YSZ and graphene mixtures with improved fracture toughness and other material properties while maintaining the material’s nanostructure dimensionality. Therefore, investigation of the compaction phenomena at non-equilibrium states will provide informative results to be used in the fabrication of bulk graphene-YSZ composites. Computational molecular dynamics (MD) simulations and impact experiments are conducted to explore and characterize the dynamic response of the YSZ variants. Molecular …

Microfabrication And Characterization Of Freestanding And Integrated Carbon Nanotube Thin Films, Derric Benjamin Syme

Theses and Dissertations

This work chronicles the fabrication of two unique thin films using carbon nanotubes. The first is a carbon film made primarily from vertically grown carbon nanotubes (CNTs) and rolled into lateral alignment. The second is an insulating film created by CNTs as a scaffolding to create a porous silica layer. Each topic represents a different method of utilizing CNTs for thin-film fabrication.Investigation of an entirely carbon thin film, comprised of aligned and laterally oriented carbon nanotubes was performed. The thin film was strengthened by deposition of amorphous carbon for a total thickness of <<> 5 µm. This thickness is thinner than …

Analysis Of Distortion Transfer And Generation Through A Fan And A Compressor Using Full-Annulus Unsteady Rans And Harmonic Balance Approaches, Daniel Robert Soderquist

Theses and Dissertations

Understanding distortion transfer and generation through fan and compressor blade rows is able to assist in blade design and performance prediction. Using full annulus unsteady RANS simulations, the effects of distortion as it passes through the rotor of a transonic fan at five radial locations (10%, 30%, 50%, 70%, and 90% span) are analyzed. The inlet distortion profile is a 90-degree sector with a 15% total pressure deficit. Fourier distortion descriptors are used in this study to quantitatively describe distortion transfer and generation. Results are presented and compared for three operating points (near-stall, design, and choke). These results are used …

Mesoscale Modeling Of Shape Memory Alloys By Kinetic Monte Carlo–Finite Element Analysis Methods, Adam David Herron

Theses and Dissertations

A coupled kinetic Monte Carlo – Finite Element Analysis (kMC–FEA) method is developed with a numerical implementation in the Scalable Implementation of Finite Elements at NASA (ScIFEN). This method is presented as a mesoscale model for Shape Memory Alloy (SMA) material systems. The model is based on Transition State Theory and predicts the nonlinear mechanical behavior of the 1st order solid–solid phase transformation between Austenite and Martensite in SMAs. The kMC–FEA modeling method presented in this work builds upon the work of Chen and Schuh [1, 2]. It represents a “bottom-up” approach to materials modeling and could serve as a …

Experimental Investigation Of The Manufacture Of Tunable Graphene Oxide Filter Membranes Using Intense Pulse Light, Joshua H Kotter

Electronic Theses and Dissertations

Reduced graphene oxide is a thin, strong, and inexpensive material with a channel and pore structure that make it a promising candidate for a filtration material. Reduced graphene oxide has been produced and tested in the laboratory, but a lack of scalable manufacturing techniques have limited its commercial use.

This thesis has shown that graphene oxide can be rapidly manufactured with an industrially scalable flash reduction process. The flash reduction process uses 0.58 millisecond pulses from a xenon lamp to reduce the graphene oxide film in less than a minute. Results for partially reduced graphene oxide membranes tuned by the …

Numerical Analysis On Convective Cooling Augmented By Evaporative Heat And Mass Transfer For Thermal Power Plant Application, Sudipta Saha

Theses and Dissertations

This thesis work describes a numerical study on the effect of evaporative cooling on the augmentation of forced convective cooling. In recent years, on-demand phase change boosted cooling has drawn major interest where convective heat transfer is augmented/aided by evaporative heat and mass transport processes. This dual mode (convection and evaporation) cooling method is envisioned to drastically enhance the heat transfer coefficient where conventional convective cooling has already reached its maximum value and furthermore dry cooling is still a desired objective. A multi- dimensional mathematical model has been developed to conduct simulations over a range of operating parameters to obtain …

Cfd Study Of Aerodynamic Drag Reduction Tool Of A Generic Sports Utility Vehicle (Suv), Samira Ishrat Jahan

Masters Theses

The Sports Utility Vehicle (SUV) has been a popular automobile choice in North America for over 50 years due to its seating and hauling versatility and good towing capacity. This widespread popularity has resulted in manufacturers pushing for increased horsepower and cabin size. Unfortunately, the limiting factor has been fuel economy which is governed by the vehicle aerodynamics. A reduction in aerodynamic drag can result in better fuel economy. The goal of this study is to reduce the aerodynamic drag of a generic SUV and the efficient application of drag reduction devices to control flow separation. An initial study has …

Algorithm For Geodetic Positioning Based On Angle-Of-Arrival Of Automatic Dependent Surveillance-Broadcasts, Richard Allen Gross

Masters Theses

This paper develops a non-precision, three-dimensional, geodetic positioning algorithm for airborne vehicles. The algorithm leverages the proliferation of Automatic Dependent Surveillance – Broadcast (ADS-B) equipped aircraft, utilizing them as airborne navigation aids to generate an RF Angle-of-Arrival (AOA) and Angle-of-Elevation (AOE) based geodetic position. The resulting geodetic position can serve as a redundant navigation system for use during locally limited Global Navigation Satellite System (GNSS) availability, be used to validate on-board satellite navigation systems in an effort to detect local spoofing attempts, and be used to validate ADS-B position reports.

The navigation algorithm is an implementation of an Extended Kalman …

Bicitaxi, Alesis Gonsalves, Sean Flanagan, Tianhao Jiang, Brenden Stone

Mechanical Engineering Senior Theses

The purpose of this report is to provide an overview of the progress made concerning the development of a solution aimed at the transportation issues faced by residents of Puebla, Mexico, and specifically the community of Colonia Puebla. Colonia Puebla is a low-income community on the outskirts of Puebla. The overall goal is to develop and prototype a product that will alleviate some of the pressure due to the lack of accessibility of transportation and then field test said product in the target community. Ideally, the product would be able to stimulate a micro-economy to provide a source of income …

Molecularly Conductive Behavior Of Blended Polymer Electrolyte-Based Cmc/Pva, Noor Saadiah Mohd Ali, Dishen Zhang, Yuki Nagao, Ahmad Salihin Samsudin

Makara Journal of Technology

This study investigated the electrical conduction and structural behavior of blended polymer electrolyte (BPE)-based carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA) in the development of solid-state electrochemical devices. Based on impedance spectroscopy and correlating Fourier transform infrared (FTIR) with thermogravimetric analysis, a framework was proposed to explain the structural enhancement of the BPE system. As revealed by FTIR, the optimum conductivity of CMC/PVA BPEs was 9.21 × 10−6 Scm−1 for 80:20 composition attributed to the intermolecular attraction between the polymers. Thermal stability of the CMC/PVA was influenced by the formation of a hydrogen bond between the hydroxyl (-OH), carboxylate (-COO-), …

Multistage Sonication Effect On The Composition And Properties Of Degraded Chitosan Product, Nurul Laili Arifin, Emma Savitri, Anjar Indah, Fesa Putra, Sumarno Sumarno

Makara Journal of Technology

The sonication method randomly breaks polymer chains to produce a varied distribution of products. A scheme with multi-stage sonication steps is proposed to identify oligomers and low molecular weight chitosan based on changes to the degrad-ed product. For each sonication level, 1% (w/v) chitosan in 1% (v/v) aqueous acetic acid was sonicated for 120 min at 60 °C. The products of the sonication treatment were deprotonized by adding an alkali solution, freeze dried and insoluble product re-sonicated until a low molecular weight was produced. Low molecular weight chitosan/insoluble products were character-ized with Fourier-transform infrared spectra (FT-IR) and X-ray diffraction (XRD) …

Data Fusion Method Based On Adaptive Kalman Filtering, Bernadus Herdi Sirenden

Makara Journal of Technology

This paper discusses data fusion methods to combine the data from a rotary encoder and ultrasonic sensor. Both sensors are used in a micro-flow calibration system developed by the Research Center of Metrology LIPI. The methods studied are hierarchical data fusion and Kalman filtering. Three types of Kalman filters (KFs) are compared: the conventional Kalman filter and two adaptive Kalman filters. Moreover, a method to combine the uncertainty results from KF in hierarchical data fusion is proposed. The aim of this study is to find appropriate methods of data fusion that can be implemented in micro-flow calibration systems. Data from …

Study Of Zno Nanospheres Fabricated Via Thermal Evaporation For Solar Cell Application, Fatin Farisha Alia Azmi, Bouchta Sahraoui, Saifful Kamaluddin Muzakir

Makara Journal of Technology

A solar cell is a device that absorbs light energy to generate electrical energy. A typical example of a solar cell is the quantum dot solar cell (QDSC), which consists of three main components: (i) fluorophore: the component that absorbs light and generates excited state electrons and holes, (ii) photoelectrode: the component that transports the excited state electron and prevents recombination of excited state electrons and holes, and (iii) electrolyte: the component that re-plenishes the vacancy left by the excited electron in the hole. Despite the increasing number of research in the QDSC field, to date, a device with significant …

Sorption-Based Energy Storage Systems: A Review, Kyaw Thu, Nasruddin Nasruddin, Sourav Mitra, Bidyut Baran Saha

Makara Journal of Technology

Mismatched timing between the supply and demand of energy calls for reliable storage systems. Energy storage systems have become further significant with the widespread implementation of renewable energy. These systems can mitigate problems that are often associated with renewable energy sources such as supply unreliability while meeting the de-mand during peak hours. Energy can be stored in various forms, yet storage systems can be generally grouped based on their output forms, namely (i) electricity and (ii) heat or thermal energy. Electrical energy is the most convenient and effective form since it can power almost all modern devices. However, the electricity …

Electrical Properties Of A Novel Solid Biopolymer Electrolyte Based On Algi-Nate Incorporated With Citric Acid, Ahmad Faizrin Ahmad Fuzlin, Noor Syahida Ismail, Yuki Nagao, Ahmad Salihin Samsudin

Makara Journal of Technology

In the present study, a novel solid biopolymer electrolyte (SBE) system is introduced by doping citric acid into alginate polymer. A sample of the alginate-citric acid SBE system was prepared via a solution casting technique. Using electrical impedance spectroscopy (EIS), the electrolytes of alginate-citric acid analyzed from 5 Hz to 1 MHz achieved the highest conductivity at 20 wt.% of 5.49 × 10-7 S cm-1. The temperature dependence of various citric acid amounts obeyed the Arrhenius rule with R2~1, where all SBE systems were thermally activated with increasing temperature. The dielectric studies of the alginate-citric acid SBE system showed non-Debye …

Skeletal Muscle Recovery And Vibration, Garrett Collier Jones

Theses and Dissertations

In the past decade there has been a significant increase in focus on the effect upper body vibration (UBV) has on the recovery of skeletal muscle after exercise-induced muscle damage. Recovery can be defined and investigated using a wide variety of methods. This study used three different measurements to track muscle recovery over 7 days following an exercise muscle damage protocol and applied vibration to a mathematical model. A visual analog scale (VAS) was used to measure muscle pain, a strain gauge was used to obtain maximum voluntary isometric contraction (MVIC) strength measurements, and shear wave elastography (SWE) represented muscle …

Geometry Based Synthesis Of Planar Compliances With Redundant Mechanisms Having Five Compliant Components, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

In this paper, a geometric approach to the passive realization of any planar compliance with a redundant compliant mechanism is presented. The mechanisms considered are either simple serial mechanisms consisting of five elastic joints or simple parallel mechanisms consisting of five springs. For each type of mechanism, realization conditions to achieve a given compliance are derived. The physical significance of each condition is identified and graphically interpreted. Geometry based synthesis procedures to achieve any given compliance are developed for both types of mechanisms. Since each realization condition imposes restrictions solely on the mechanism geometry, the procedures allow one to choose …

Partial Pressures And High-Temperature Thermodynamic Properties For The Germanium-Tellurium System, Robert F. Brebrick

Mechanical Engineering Faculty Research and Publications

Our earlier optical density measurements over Ge-Te compositions are reanalyzed. Spectral characteristics of the GeTe(g) spectrum are determined from measurements with a 1 at.% Te sample near 1200 K. Beers law constants for GeTe(g) are established by requiring consistency between spectroscopic results for the dissociation of GeTe(g) into Ge(g) and Te₂(g) and our description in terms of the partial pressure of Te₂ and the partial optical density of GeTe over Ge saturated GeTe(c). Between 870 and 997 K the partial pressures over Ge saturated GeTe(c) are ln P(Te₂,atm) = − 24,800/T + 17.600 and ln …

Structural Health Monitoring And Non-Destructive Inspection Of Composite And Metallic Structures, Asaad Qasim Migot

Theses and Dissertations

Structural Health Monitoring (SHM) and Nondestructive Testing (NDT) techniques are being used as effective tools for investigating variety of civil, mechanical, and aerospace applications. In recent years, these techniques become such incredible tools for continuously monitoring of various structures. The aim of the dissertation work is to develop SHM and NDT methodologies for acoustic emission sources localization, damage detection and quantification in metallic and composite structures using a network of sensors, guided wave and developed imaging methods. This work is implemented through preparing metallic and composite specimens, setting up experiments, designing efficient networks of sensors, modeling guided wave interaction with …

Plasma Surface Functionalization Of Afp Manufactured Composites For Improved Adhesive Bond Performance, Ibrahim Sarikaya

Theses and Dissertations

High-performance composite structures not only require a reliable fabrication process when creating primary structures, but also a high fidelity and repeatable bonding process for the assembled components. During the assembly process, surface contaminants are a major concern as they have the potential to compromise the bond quality resulting in poor bond strength, low failure load, and undesirable failure modes of the adhesively bonded structures. This is further complicated by composite materials inherently possessing low surface energy and thus exhibiting low adhesive property. Therefore, detecting and removing contaminants on the pre-bond composite surface is an active research topic in pursuit of …

Surface Science And Engineering Of Nano-Structured Cathodes For Intermediate Temperature Solid Oxide Fuel Cells, Yeting Wen

Theses and Dissertations

The bulk-to-surface Sr-segregation can seriously compromise the stability of oxygen electrocatalysis in Sr-doped perovskite oxides such as La1-xSrxCoO3-δ and La1-xSrxCo1- yFeyO3-δ and limit their practical applications as cathode materials in solid oxide fuel cells. Although such chemical instability has been actively studied in recent years, fundamental understanding of Sr-segregation process vs temperature and time, particularly under real-world conditions, as well as the suppression method, are still needed. This PhD dissertation aims to acquire fundamental knowledge of Sr-segregation process under practical conditions in solid oxide fuel cells and develop suppression method to ensure the long-term stability through surface modifications.

To gain …

Acoustoelastic Metamaterial With Simultaneous Noise Filtering And Energy Harvesting Capability From Ambient Vibrations, Fariha Mir

Theses and Dissertations

Harvesting unused and untapped energy from ambient vibration noise and acoustic sound waves is an emerging field of research in the recent years. Utilization of the energy with a wide band of the frequency spectrum from the vibrational sources alone stands as one of the most promising ways to power small electronic devices, smartphones, local structural health monitoring (SHM) sensors and home and workshop appliances. Various sources of ambient vibration and acoustic noise can be found around us in our everyday life. These sources are abundant in almost all the engineering industries and manufacturing facilities for example in aerospace, mechanical …