Mechanical Engineering Commons^™

Numerical Simulation Of Nonlinear Vibrations Of Discrete Mass With Harmonic Force Perturbation, M. Yusupov, B. A. Akhmedov, Olga Karpova

Acta of Turin Polytechnic University in Tashkent

The problem of vibration of a single-mass system under the force excitation of vibration associated with a fixed base by a weightless nonlinear viscoelastic spring is considered. To take into account the rheological properties of the spring material, the Boltzmann-Volterra principle was used. Mathematical models of the problem under consideration are obtained, which are described by integro-differential equations. A solution method based on the use of quadrature formulas has been developed and a computer program has been compiled on its basis, the results obtained are presented in the form of graphs. The influence of nonlinear and rheological properties of a …

Design And Control Techniques Of The Open-Circuit Subsonic Wind Tunnel With Closed Testing Section, Jamshid Yakhshilikov, Jamshid Inoyatkhodjaev

Acta of Turin Polytechnic University in Tashkent

This paper will describe the design and control techniques of the open-circuit subsonic wind tunnel with closed testing section (WT) for study purpose. The goal is to design a WT that can be tested at a wind speed of 30 m/s, where the desired cross-sectional area of the test chamber is 0.5x0.5 m. The pressure drop inside the WT has been calculated in order to select one of the available axial fans from the manufacturer’s catalog, and computational fluid dynamics (CFD) was performed to check the result. In order to obtain a smooth airflow in the test section, a proportional …

Solar Photovoltaic Performance Monitoring: A Bibliometric Review, Research Gaps And Opportunities, Javed Sayyad, Paresh Nasikkar

Library Philosophy and Practice (e-journal)

Electrical power generation has been revolutionized by growing demand and use of Renewable Energy (RE) sources such as Solar Photovoltaic (SPV) as the main electricity source in modern times. The main objective of this bibliometric analysis is to understand the scope of the literature available for SPV performance characterization. This detailed reviewed was performed on the documents related to SPV research considering all the subject categories from Scopus and Web of Science (WoS) databases. The patterns for the particular set of keywords were broke down with the recuperated outcomes from Scopus database in the language, publication type, year of publication, …

Feasibility Study Of A Micro-Electro-Mechanical-Systems Threshold-Pressure Sensor Based On Parametric Resonance: Experimental And Theoretical Investigations, Mark Pallay, Meysam Daeichin, Shahrzad Towfighian

Mechanical Engineering Faculty Scholarship

A tunable threshold pressure sensor based on parametric resonance of a microbeam subjected to electrostatic levitation is proposed. Parametric excitation can trigger a large amplitude vibration at twice the natural frequency if the magnitude of the driving force is large enough to overcome energy loss mechanisms in the system such as squeeze film damping. This causes a temporarily unstable response with a significant gain in oscillation amplitude over time until it is eventually capped by nonlinearities in the force or material or geometric properties. The instability divides the frequency region into two regions: distinct responses bounded by the system non-linearity, …

Exploring A Platinum Nanocatalytic Microcombustion-Thermoelectric Coupled Device, Dylan Moore Mcnally

Theses and Dissertations

This work aimed to create a first-generation power device for eventual application to portable electronics. A platinum nanoparticle catalytic substrate was employed in a microcombustion-thermoelectric coupled (MTC) device for the purpose of chemical-to-electrical energy conversion. Multiple microcombustion reactors were designed, fabricated, and investigated. Most importantly, the reactor configuration was designed to accommodate thermoelectric generators (TEGs) for power production. Temperature studies with catalytic combustion of methanol-air fuel mixtures were used to evaluate the thermal power generation performance of each reactor. The final reactor design enabled ignition at room temperature with the ability to achieve repeat catalytic cycles upon subsequent exposure to …

Spectral Absorption Coefficient Of Additive Manufacturing Materials, Nicholas J. Wallace, Matthew R. Jones, Nathan B. Crane

Faculty Publications

Active thermography techniques are of interest for quality assurance of additive manufacturing processes. However, accurate measurements of thermophysical properties of materials are required to successfully implement active thermography. In particular, the spectral absorption coefficient of materials commonly used in additive manufacturing must be known to accurately predict the spatial distribution of thermal energy generated from absorption of power emitted by a laser or pulsed flash lamp. Accurate measurements of these optical properties are also needed to develop greater understanding of additive manufacturing processes that rely on radiative heat transfer to fuse powders. This paper presents spectral absorption coefficient measurements and …

Advanced Thermal Characterization And Temperature Control To Enable The Next Generation Of Micro-Electronic Technologies, Assaad El Helou

Mechanical Engineering Research Theses and Dissertations

In the electronics world, self-heating is an inevitable by-product of electrical activation that has a major impact on device performance and reliability. Thermal technologies have been in constant development to effectively dissipate the generated heat and keep device operation temperatures within reliable limits. Moreover, thermal characterization technologies have been implemented to understand the thermal performance within microelectronic sys- tems, but not without facing experimental and numerical challenges. This work presents ad- vanced thermal investigations, both experimental and numerical, that are adapted and most suited for emerging micro-electronic technologies. Initially, the main experimental and numerical modeling challenges faced in the thermal …

Microparticle Propulsion For In Vivo Navigation, Louis Rogowski

Mechanical Engineering Research Theses and Dissertations

Microscale propulsion impacts a diverse array of fields, with simplistic microrobots allowing for novel innovations in microscale surgery and drug delivery. Propulsion at the microscale is constrained by physics, with time-reversal and geometric symmetries limiting available propulsion mechanisms. However, certain fluid environments and surface coatings allow for the propulsion of microparticles through externally applied magnetic fields. Presented here is a detailed analysis of microparticles propelling using spontaneous symmetry breaking, flagella surface coatings, and multi-modal actuation mechanisms. Spontaneous symmetry breaking in nonlinearly viscoelastic fluids is presented for the first time in literature, with two equal and opposite propulsion states existing along …

The Effect Of Surface Air Entrapment On Oscillating Fin Flow At Intermediate Reynolds Number, Nicholas Davis

Mechanical Engineering Research Theses and Dissertations

Oscillating fin flow has been a subject of study due to its simplicity and similarity to aquatic propulsion methods found in nature. At intermediate Reynolds numbers, in the range of 10 to 1000, drag tends to have a larger impact than at higher Reynolds numbers and the boundary layer thickness on the fin surface tends to be larger, which can alter the vortices shed during oscillation. To attempt to reduce these effects, an apparent slip condition may be placed on the surface of the fin. In this investigation, entrapment of pneumatically supplied air at a perforated fin surface was used …

Detection Of Nucleotides In Hydrated Ssdna Via 2-D H-Bn Nanopore With Ionic-Liquid/Salt-Water Interface, Jungsoo Lee

Multidisciplinary Studies Theses and Dissertations

Accomplishing slow translocation speed with high sensitivity has been the greatest mission for solid-state nanopore (SSN) to electrically detect nucleobases in single-stranded DNA (ssDNA). In this study, a method to detect nucleobases in ssDNA using a SSN is introduced by considerably slowing down the translocation speed and effectively increasing its sensitivity. The ultra-thin titanium dioxide (TiO₂) coated hexagonal boron nitride (h-BN) nanopore was fabricated, along with an ionic-liquid [bmim][PF₆]/2.0 M KCl aqueous (cis/trans) interfacial system, to increase both the spatial and the temporal resolutions. As the ssDNA molecules entered the nanopore, a …

Thermo-Fluid Characterizations Of The Powder-Bed Fusion Additive Manufacturing Processes Using Laser And Electron Beam, M Shafiqur Rahman

LSU New Orleans Theses and Dissertations

The powder-bed fusion (PBF) process is a subdivision of Additive Manufacturing (AM) technology where a heat source at a controlled speed selectively fuses regions of a powder-bed material to form three-dimensional (3-D) parts. Two of the most effective PBF processes are selective laser melting (SLM) and electron beam additive manufacturing (EBAM), which can fabricate full-density metallic parts in a layer-by-layer fashion. In this study, thermal behavior and melt-pool dynamics in the PBF process are investigated by developing 3-D multiphysics-based thermo-fluid models for both SLM and EBAM, containing Ti-6Al-4V alloy as a powder-bed material. The laser and electron beams are modeled …

A Numerical And Experimental Study Of Lid Driven Square Cavity Flow For Laminar And Turbulent Cases, Abdullah Bin Naeem

LSU New Orleans Theses and Dissertations

Experimental and numerical studies are performed on steady and unsteady lid-driven cavity flow for laminar flow regime. In the experiments, a PIV and an LDA were employed to measure the global and local velocities, respectively inside a cavity of AR 1.0. The velocity vector plots and streamline plots which represent unsteady circulation patterns are obtained using the PIV. The steady local velocities measured with LDA are then used to calibrate the PIV measurements. The numerical study is performed using a commercial CFD solver. For turbulent flow simulation RANS equations with K-Epsilon closure model were used. From the PIV calibration study, …

Mechanical Engineering News, Georgia Southern University

Mechanical Engineering: News & Publications (2013-2023)

• Mechanical Engineering Graduate Featured in University News

Investigating The Performance Of A Novel Multi-Element Airfoil Concept Using Numerical Analysis, Ahmed Elbaz

Mechanical Engineering

Separation control is one of the trending topics recently for Vertical Axis Wind Turbine (VAWT) applications, flow separation that occur on the suction side of an airfoil is a major limitation for VAWTs starting and power coefficient; passive control of flow separation has been attracting wind energy research community recently. The principle objective of this paper is to investigate the effect of the multi-element airfoil on the aerodynamic characteristics at wide range of angles of attack at a Reynolds number of 140,000. The multi element airfoil modification has been implemented by replacing the baseline airfoil with two airfoil members within …

Numerical Investigation On The Effect Of Surface Perturbations On Aerodynamics Of Cambered Airfoils, Ahmed Elbaz

Mechanical Engineering

The issue of the flow separation and the urge to reach higher performance ratings in airfoils can be acquired through the passive surface modification. By altering the shape of the upper surface to have a perturbated shape using a simple sinusoidal wave, the flow characteristics of airfoils can be enhanced to yield higher desired outputs. This study proposes the effect of both the wave amplitude and the number of waves for the perturbated upper surface on the lift and drag characteristics for SG-6040 and SG-6042 airfoils. Perturbating the upper surface of the airfoil can be of a great advantage as …

Numerical Investigation Of Flow Over An Airfoil With Active Cavity, Ahmed Elbaz

Mechanical Engineering

Wind turbine blades are commonly made of airfoils due to their high lifting characteristics. The performance of the airfoils can reach higher optimal conditions with applying various modifications on the airfoil geometry.  The need to improve airfoil performance at low values of Reynolds number is essential to small power wind turbines. Therefore, the objective of this study is to investigate methods to increase the lift to drag ratio, which results in better aerodynamic performance of the airfoil used in wind turbines at low Reynolds number using active flow control by employing a surface cavity with suction. The investigation considered both …

1. Test Data, Zhiqu Lu, Likun Zhang, Lei Cao

Gulf Research Program Data Sets

This data set contains recorded and processed bubble sounds under different conditions: a few bubbles vs. constant flow bubbles. Each condition is tested with nitrogen and with methane.

2. Modeling, Zhiqu Lu, Likun Zhang, Lei Cao

Gulf Research Program Data Sets

This data set contains the results for acoustic bubble modeling.

3. Localization, Zhiqu Lu, Likun Zhang, Lei Cao

Gulf Research Program Data Sets

This data set contains the results for oil leakage source localization.

4. Metadata Files, Zhiqu Lu, Likun Zhang, Lei Cao

Gulf Research Program Data Sets

This data set contains all ReadMe files for test data, modeling data, and localization data, as well as the corresponding codes.

5. Programs And Algorithms, Zhiqu Lu, Likun Zhang, Lei Cao

Gulf Research Program Data Sets

This data set contains all codes for the study.

6. Supplemental Materials, Zhiqu Lu, Likun Zhang, Lei Cao

Gulf Research Program Data Sets

This data set contains all conference presentations, manuscripts, technical reports, posters.

Industry 4.0 In The Retail Sector: Sustainability Of Food Retail With A Focus On Food Insecurity In Dayton, Oh, Katrina Alexis Coleman

Honors Theses

In recent years, large scale agricultural and food processing industries have experienced a great worldwide digital transformation. The advent of Industry 4.0, which has become popular in Europe, has helped many industries optimize their operations. Relatively new is the idea that food processing industries and other stakeholders in the food distribution supply chain cannot only optimize their processes but also, track and provide timely customer service. This has technical and managerial challenges that might limit the potential benefits of industry 4.0 in the efficient distribution of fresh food produce. For example, food retailers have to meet the increasing customer desire …

Designing And Implementing A Peer-To-Peer Led Behavioral And Energy Reduction Program For Low-Income Neighborhoods, Jenn Hoody

Honors Theses

Reduction in energy consumption from fossil fuels is a necessary step toward combating climate change as more and more studies are revealing the catastrophic outcomes if the current trends do not change. Residential programs generally managed by energy utilities promoting energy cost savings and reduced consumption are being enacted to decrease the greenhouse emissions. However, thus far, little to no measures have been taken to extend the reach of such programs to low-income communities. Reducing household energy consumption would be particularly beneficial for these communities as it would lower utility bills for low-income households who spend a substantially greater portion …

Upper Extremity Motion Assessments In Virtual Reality Environments, Lanna Nicole Klausing

Honors Theses

Traditional upper extremity rehabilitation techniques often utilize tedious and repetitive reaching motions. Fully immersive virtual reality (VR), involving a VR headset, is a technology with the potential to have non-gaming uses and applications, specifically as an upper extremity rehabilitation tool. This study was designed with the long-term goal of evaluating immersive VR as an upper extremity rehabilitation tool. The purpose of this research is to quantify different movement deficits that may arise due to MS or Parkinson’s, and to understand how the motions of patients with MS or Parkinson’s may differ from healthy controls. This thesis documents the first step …

Effect Of Airfoil-Preserved Undulations On Wing Performance And Wingtip Vortex, Faith A. Loughnane

Honors Theses

The effect of undulation placement (leading edge, trailing edge, leading and trailing edge) on the wing performance and the wingtip vortex was investigated. Experiments were performed at the University of Dayton Low Speed Wind Tunnel (UD-LSWT) on undulated wings where the NACA 0012 airfoil cross-section is preserved along the wingspan. Sensitivity studies were done on the undulation wavelength along the span (λ/c 0.31, 0.21 and 0.15) and undulation placement (leading edge, trailing edge, and both leading and trailing edge). The leading edge undulations delayed stall until higher angles of attack, however, the maximum aerodynamic efficiency was reduced. The trailing edge …

Interface Engineering Of Materials For Energy And Biological Applications, Ardalan Chaichi

LSU Doctoral Dissertations

Interface interactions are generally classified into solid-liquid, solid-gas, solid-vacuum, liquid-gas, light-matter and electron-matter categories. Surface morphological studies as well as surface chemical reactions can be studied in various types of complex systems thanks to technological advances in materials characterization methods. By employing interface engineering in different applications, it is possible to control electrical, chemical, mechanical, optical and biological properties of materials. Accordingly, we have applied interface engineering in three different areas of energy materials, biomaterials and surface imaging. As a result, firstly, we have introduced a high intensity light flash-based method on engineered substrates for delamination of reduced graphene oxide …

Florida Building Code, Energy Conservation, 7th Edition (2020) Vs. 2018 International Energy Conservation Code Residential Stringency Analysis, Florida Solar Energy Center, Jeffrey Sonne

FSEC Energy Research Center®

This report summarizes the review and evaluation activities carried out to make a determination whether the residential provisions of the 7th Edition (2020) Florida Building Code, Energy Conservation meet or exceed those of the 2018 International Energy Conservation Code (IECC) code.

Numerical Evaluation Of Effective Thermal Response Of Heterogeneous Materials, Kevin W. Irick

Mechanical Engineering ETDs

Heterogeneity in materials leads to increased complication of physics, at the level or scale where heterogeneity exists, making analysis and material behavior predictions more difficult. As a result of the intricate descriptions or understanding of the physics required to determine the behavior of a heterogenous material or system, practitioners frequently prefer the use of effective properties or responses. This body of work is dedicated to performing computational analyses on the thermal behavior of heterogeneous materials and evaluating the corresponding analyses using formal verification approaches. Custom finite element method code was used for solving the heat equation in a variety of …

Solar Insolation Micro-Forecasts Using Longwave Infrared Sensors And Artificial Intelligence, Anthony R. Menicucci

Mechanical Engineering ETDs

Solar Insolation Micro-Forecasts (SIMF) are used by Independent Service Operators (ISOs) and other grid operators to maintain constant and stable electrical grid frequency, voltage, power factor and waveform across their transmission infrastructure. Intermittent, thick, dense and typically cumulus clouds negatively impact the electrical grid by quickly turning on and off power production from large solar photovoltaic (PV) fields, causing grid stability problems between generation and load. Forecasting insolation values over large PV fields allows operators the chance to anticipate and proactively implement mitigation strategies like engaging spinning reserve from gas turbines, deploying generators, buying power in the spot market, and …