Mechanical Engineering Commons^™

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 …

A Study Of Thermal Energy Storage Of Phase Change Materials: Thermophysical Properties And Numerical Simulations, Kyung-Eun Min

Dissertations and Theses

A Thermal Energy Storage (TES) system is meant for holding thermal energy in the form of hot or cold materials for later utilization. A TES system is an important technological system in providing energy savings as well as efficient and optimum energy use. The main types of a TES system are sensible heat and latent heat. A latent heat storage is a very efficient method for storing or releasing thermal energy due to its high energy storage density at constant temperatures, and a latent heat storage material can store 5-14 times more heat per unit volume than a sensible heat …

Cpu Cooling Pulse Device For Enhanced Heat Transfer, Hannah Farabee, Noémie L. Iñiguez, Hugo Nunez, Wendy Zwanka

Senior Theses

Ice Dragon Cooling is a company which researches thermofluids and heat transfer technologies. The company’s present research focuses on HVAC and computer applications, with an emphasis on nanofluid development. To support Ice Dragon’s mission, the company wants a product that enhances heat transfer efficiency in liquid-cooled CPU systems. The product is to be a pulse device which increases the turbulence of a liquid across a computer CPU cooling block, thereby expediting heat transfer away from the CPU.

The needs for Ice Dragon Cooling were determined based on engineering knowledge and industry consultation. After further analysis, it was determined that increasing …

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 …

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 …

Development Of Scalable And Tunable Super- Hydrophilic And - Hydrophobic Coatings On The Cu Substrate For Phase Change Heat Transfer Applications, Raikan Saad Dawas

Theses and Dissertations

The aim of this study is to enhance and sustain the thin liquid film evaporation (TLFE) as well as dropwise condensation (DWC) on scalable copper substrates. The current dissertation consists of two sections. The objective of the first section is to enhance the dry cooling technology which is widely used in industrial applications such as in the air side of power plants, AC unit, or electronic cooling. However, the thermal dissipation performance is limited with low heat transfer coefficients (HTCs) due to the low thermal conductivity and density of the air. Inspired by the phase change heat transfer during the …

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 …

Friction Stir Additive Manufacturing(Fsam) Of 2050 Al-Cu-Li Alloy, Ilana Lu

Theses and Dissertations

As a solid state process, friction stir welding (FSW) is an advantageous joining method for higher strength aluminum alloys such as 2050 Al-Cu-Li which are not readily fusion welded. This study explores the potential of friction stir lap welding (FSLW) as an additive manufacturing process for this aluminum-lithium alloy. To accomplish this, lap weld joints were performed so that each additional layer would penetrate the preceding weld pass which creates a large, stacked build. Excess material is machined away leaving only weld. Cast AA2050 is explored in this study as a more cost-efficient feedstock for this process as compared to …

Modeling Piezoresistive Effects In Flexible Sensors, Marianne E. Clayton

Theses and Dissertations

This work describes a model of the piezoresistive behavior in nanocomposite sensors. These sensors are also called flexible sensors because the polymer matrix allows for large deformations without failure. The sensors have conductive nanoparticles dispersed through an insulative polymer matrix. The insulative polymer gaps between nanoparticles are assumed to be possible locations for electron tunneling. When the distance between two nanoparticles is small enough, electrons can tunnel from one nanoparticle to the next and ultimately through the entire sensor. The evolution of this gap distance with strain is important to understand the overall conductivity of the strain sensor. The gap …

Aerodynamic Design Optimization Of A Locomotive Nose Fairing For Reducing Drag, Chad Lamar Stucki

Theses and Dissertations

Rising fuel cost has motivated increased fuel efficiency for freight trains. At cruising speed,the largest contributing factor to the fuel consumption is aerodynamic drag. As a result of stagnationand flow separation on and around lead and trailing cars, the first and last railcars experiencegreater drag than intermediate cars. Accordingly, this work focused on reducing drag on lead locomotivesby designing and optimizing an add-on nose fairing that is feasible for industrial operation.The fairing shape design was performed via computational fluid dynamic (CFD) software.The simulations consisted of two in-line freight locomotives, a stretch of rails on a raised subgrade,a computational domain, and …

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 …

Impact Of Pulse Length On The Accuracy Of Defect Depth Measurements In Pulse Thermography, James Pierce, Nathan B. Crane

Faculty Publications

Pulse thermography is a nondestructive testing method in which an energy pulse is applied to a surface while the surface temperature evolution is measured to detect sub surface defects and estimate their depth. This nondestructive test method was developed on the assumption of instantaneous surface heating, but recent work has shown that relatively long pulses can be used to accurately determine defect depth in polymers. This paper examines the impact of varying input pulse length on the accuracy of defect depth quantification as a function of the material properties. Simulations using both thermoplastics and metals show that measurement error is …

Characterization And Optimization Of A Propeller Test Stand, Colin Bruce Leighton Benjamin

Mechanical & Aerospace Engineering Theses & Dissertations

In recent history, there has been a rapid rise in the use of drones, and they are expanding in popularity each year. The widespread use and future capabilities of these unmanned aerial vehicles (UAVs) will call for increased study and classification of propellers to maximize their performance. As a result, it is necessary to have continuity in the development, maximization, and optimization of propeller test stand’s capability to collect accurate and precise measurements. It is of significant advantage to have the capability of accurately characterizing a propeller based on its thrust and torque. In this study, a propeller test stand …

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 …

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. …

Investigation Of The Coupled Nuclear, Thermal-Hydraulic, And Thermomechanical Response Of A Natural Circulation Research Reactor Under Severe Reactivity-Initiated Accident Transients, Darren G. Talley

Mechanical Engineering ETDs

Research reactors play an important role in higher education, scientific research, and medical radioisotope production around the world. It is thus important to ensure the safety of facility workers and the public. This work presents a new reactor transient analysis code, referred to as Razorback, which computes the coupled reactor kinetics, fuel element heat transfer, fuel element thermal expansion and thermal stress, and thermal-hydraulic response of a natural circulation research reactor. The code was developed for the evaluation of large rapid reactivity addition in research reactors, with an initial focus on the Annular Core Research Reactor (ACRR) at Sandia National …

Limit Equilibrium Method-Based Shear Strength Prediction For Corroded Reinforced Concrete Beam With Inclined Bars, Yafei Ma, Baoyong Lu, Zhongzhao Guo, Lei Wang, Hailong Chen, Jianren Zhang

Mechanical Engineering Faculty Publications

Shear strength is a widely investigated parameter for reinforced concrete structures. The corrosion of reinforcement results in shear strength reduction. Corrosion has become one of the main deterioration factors in reinforced concrete beam. This paper proposes a shear strength model for beams with inclined bars based on a limit equilibrium method. The proposed model can be applied to both corroded and uncorroded reinforced concrete beams. Besides the tensile strength of longitudinal steel bars, the shear capacity provided by the concrete on the top of the diagonal crack, the tensile force of the shear steel at the diagonal crack, the degradation …

Design Of A Portable Biogas Purification And Storage System, Anikumar Kosna, Bade Shrestha

Faculty Research and Creative Activities Award (FRACAA)

The objective of this study is to propose and design a commercial portable purification and storage system to commercialize biogas (which mainly consists of 45 - 75 % of methane and 15 - 16% of carbon dioxide), produced from household/non-commercial biogas plants. The selection of purification process is based on the portability of the purification system.