Digital Commons Network^™

Heat Conduction In Cylindrical Coordinates With Time-Varying Conduction Coefficients: A Practical Engineering Approach, Lulut Alfaris, Ruben Cornelius Siagian, Aldi Cahya Muhammad, Ukta Indra Nyuswantoro, Budiman Nasution

Journal of Mechanical Engineering Science and Technology (JMEST)

This research aims to develop a mathematical method for expressing the Laplace operator in cylindrical coordinates and applying it to solve heat conduction equations in various scenarios. The method commences by transforming Cartesian coordinates into cylindrical coordinates and identifying the necessary substitutions. The result is the expression of the Laplace operator in cylindrical coordinates, which is subsequently employed to address heat conduction equations within cylindrical coordinates. Various cases encompassing different initial and boundary conditions, as well as variations in the conduction coefficient over time, are meticulously considered. In each instance, precise mathematical solutions are determined and subjected to thorough analysis. …

Vertical Shaft Kinetic Turbine Performance Using A Cup-Shape Blade, Kennie A. Lempoy, Nita C. V. Monintja, Arwanto M. A. Lakat

Journal of Mechanical Engineering Science and Technology (JMEST)

The abundant availability of alternative energy sources forms the fundamental foundation for rural energy development. In particular, renewable energy sources are indispensable in rural areas due to their ecofriendly nature and widespread accessibility, which helps preserve the environment by avoiding pollution. Indonesia, a country blessed with vast water resources, especially its rivers, holds enormous potential for harnessing kinetic energy derived from fast-flowing river waters. Effective utilization of this kinetic energy has the potential to address energy shortages in the country. In this context, there is a pressing need to enhance the efficiency of kinetic turbines designed to function as electricity …

Artificial Neural Network-Based Modeling Of Performance Spark Ignition Engine Fuelled With Bioethanol And Gasoline, Susi Marianingsih, Farhanna Mar’I, Hendry Y. Nanlohy

Journal of Mechanical Engineering Science and Technology (JMEST)

Machine learning technology can distinguish the relationship between engine characteristics and performances. Therefore, the goal of the present work is to predict the performance parameters of a singlecylinder 4-stroke gasoline engine at different ignition timings using a blended mixture of gasoline and bioethanol by an artificial neural network (ANN). Experimental data for training and testing in the proposed ANN was obtained at a dynamic speed and full load condition. An ANN model was developed based on standard Back-Propagation algorithm for the spark ignition engine. Multi-layer perception network (MLP) was used for non-linear mapping between the input and output parameters. An …

The Effect Of Adding Aluminium On The Performance Of Zno Nrs/Pani In Their Application As Photoelectrochemical Water Splitting, Eprilia Trikusuma Sari, Nandang Mufti, Anissa Chairani Alfin Nadhira, Hari Wisodo, Markus Diantoro

Journal of Mechanical Engineering Science and Technology (JMEST)

Photoelectrochemical (PEC) is a new renewable energy technology that converts H2O into hydrogen and oxygen gas with the help of sunlight. A photoelectrochemical cell device consists of three main components, one of which is the photoanode. One of the materials that can be used as a photoanode is ZnO which has good electrical properties and is non-toxic. Nanorods-structured ZnO has the advantage of being able to increase light absorption due to its high surface area. However, the resulting performance is still quite low. So it is necessary to make modifications to the photoanode, one of which is by adding aluminium …

Mechanical Characterization Of Naoh-Treated Agel Fiber-Cotton Composites, I Gusti Ngurah Nitya Santhiarsa, I Gusti Bagus Wijaya Kusuma, I Gede Artha Negara

Journal of Mechanical Engineering Science and Technology (JMEST)

Composites comprising two or more distinct materials are fabricated to enhance the mechanical properties of the constituent materials. A common approach for generating composites is vacuum infusion. This technique enables the infusion of two materials utilizing a vacuum. In the field of composite science, textile composites have emerged as an important new development. Agel rope, derived from twisting agel fibers, exhibits inferior bending strength and elongation compared to ropes fabricated from synthetic fibers. Moreover, agel rope is susceptible to bacterial decay. This study aims to characterize the mechanical properties of textile composites comprising woven agel rope subjected to NaOH treatment. …

Heat Transfer Performance Of Single-Phase Circular Heat Sink With Micro Pin-Fin Structures, Mouza Abdulla Al Shamsi

Thesis/ Dissertation Defenses

This thesis presents a numerical study of laminar forced convection in a novel design of a microscale single phase water cooed circular heat sink with pin fins developed and analyzed to serve as a miniaturized cooling system. The developed heat sink in this study aims to achieve efficient heat dissipation from high electronics integration that generates high heat flux and non-uniform temperature distribution, which leads to the reduction of life and reliability of electronic devices. Numerical analysis of ten different configurations of the circular heat sink has been carried out for the heat flux of 1000 kW/m2 at range of …

Efficient Navigation And Motion Control For Autonomous Forklifts In Smart Warehouses: Lspb Trajectory Planning And Mpc Implementation, Konchanok Vorasawad, Myoungkuk Park, Changwon Kim

Michigan Tech Publications

The rise of smart factories and warehouses has ushered in an era of intelligent manufacturing, with autonomous robots playing a pivotal role. This study focuses on improving the navigation and control of autonomous forklifts in warehouse environments. It introduces an innovative approach that combines a modified Linear Segment with Parabolic Blends (LSPB) trajectory planning with Model Predictive Control (MPC) to ensure efficient and secure robot movement. To validate the performance of our proposed path-planning method, MATLAB-based simulations were conducted in various scenarios, including rectangular and warehouse-like environments, to demonstrate the feasibility and effectiveness of the proposed method. The results demonstrated …

Dynamics And Scaling Of Particle Streaks In High-Reynolds-Number Turbulent Boundary Layers, Tim Berk, Filippo Coletti

Mechanical and Aerospace Engineering Faculty Publications

Inertial particles in wall-bounded turbulence are known to form streaks, but experimental evidence and predictive understanding of this phenomenon is lacking, especially in regimes relevant to atmospheric flows. We carry out wind tunnel measurements to investigate this process, characterizing the transport of microscopic particles suspended in turbulent boundary layers. The friction Reynolds number Re_𝜏 = O(10⁴) allows for significant scale separation and the emergence of large-scale motions, while the range of viscous Stokes number St⁺ = 18–870 is relevant to the transport of dust and fine sand in the atmospheric surface layer. We …

The Effects Of Engineering Summer Camps On Middle And High School Students’ Engineering Interest And Identity Formation: A Multi-Methods Study, Timothy Robinson, Adam Kirn, Jenny Amos, Indira Chatterjee

Journal of Pre-College Engineering Education Research (J-PEER)

This multi-methods study explores changes in engineering interest and identity of middle and high school students (n = 79) attending introductory-level engineering summer camps at a large western land grant university. Middle school is a critical time when student interest, identity, and subsequently career choice begin to emerge and hence it is important that at this age students are given accurate information about engineering majors in college and future career opportunities in engineering. Data were collected over a period of two years in six summer camps. Three separate populations of middle and high school students participated in the summer …

What Does It Mean To Be “Prepared For Work”? Perceptions Of New Engineers, Jessica R. Deters, Marie C. Paretti, Logan A. Perry, Robin Ott

Department of Mechanical and Materials Engineering: Faculty Publications

Background: Engineering education seeks to prepare students for engineering practice, but the concept of preparedness is often ill-defined. Moreover, findings from studies of different populations or in different contexts vary regarding how well new graduates are prepared. These variations, coupled with the lack of clarity, suggest the need to better understand what it means to be prepared for engineering work.

Purpose: This study contributes to research on workplace preparation by exploring how new graduates describe being prepared for engineering work.

Method: Applying secondary analysis to data from the multi-institution Capstone To Work (C2W) project, we used thematic …

Comparative Evaluation Of Investigation Methods For Estimating The Load-Dependent State Of Charge And End Of Discharge Of A Multirotor Uav Battery, Hanna Dibbern, Morten Roßberg, Claudia Werner

Journal of Aviation Technology and Engineering

As the scope of multirotor unmanned aerial vehicle (UAV) applications increases, more attention is being paid to UAV energy requirements, which vary depending on the mission profile. To obtain accurate information about the UAV battery during flight, the idea of a digital twin including a battery state estimation model is promising. For battery state estimation, a Kalman filter combination is the preferred approach in the literature. Comparing different Kalman filters, the unscented Kalman filter has a more accurate estimation for nonlinear systems compared to the extended Kalman filter. In the application of UAV flight with load-dependent flight missions, the comparison …

Stereoscopic-Based Mass Properties Estimation For Warhead Fragments, Alessia Nocerino, Katharine Larsen, Riccardo Bevilacqua, Elisabetta L. Jerome

Student Works

FRAGMENTATION characteristics such as spatial distribution, number of fragments, fragment velocity, and fragment mass can be used to characterize the lethality of a fragmenting weapon or any metal cased explosive [1,2]. However, most warhead tests and evaluations are limited to static arena testing, where fragment characteristics must be collected by hand. Recently, stereoscopic imaging techniques have been added to static arena tests. Using this method, position tracks can be collected for each fragment, and then velocity information can be found. This paper proposes a method to estimate the mass and moment of inertia using data collected by a stereoscopic imaging …

Employment Of Intelligent Predictive Maintenance On Thermal Power Plant Component Parts Taking Condenser Vacuum As A Case Study, Titus Ajewole

Tanzania Journal of Engineering and Technology (TJET)

This work proposes deployment of machine learning in the maintenance of individual constituent parts of steam power plant assemblages. With the condenser vacuum of a steam turbine (in a six-turbine plant assemblage) taken as a case study, information on the past operating parameters of the selected plant component was used to forecast its future working condition. Based on Exponential Gaussian Process of Regression, a model was developed, trained using the diachronic operational data, and employed in determining the future. A quantitative evaluation was employed to provide the distribution of the test values of the data about the lines of regression, …

Wind Farm Optimization And Analysis Of Complex Wake Structures, Rubel Chandra Das

Mechanical Engineering ETDs

A high-fidelity computational solver was developed with direct numerical simulation (DNS), large eddy simulation (LES), and Concurrent Precursor Method (CPM) capabilities. Extensive validation ensured the solver's accuracy in modeling fluid dynamics, including the wake characteristics of both utility and miniature-scale wind turbines. Key performance statistics (e.g., velocity and turbulence intensity profiles) were compared against established theoretical, computational, and experimental results. The study examined the influence of ground clearance on turbine performance, comparing two scenarios with different hub heights. Results showed that larger ground clearance facilitates quicker wake recovery. Finally, the study uses a nine-turbine array model to explore wind farm …

Computational Modeling Using A Novel Continuum Approach Coupled With Pathway-Informed Neural Networks To Optimize Dynein-Mediated Centrosome Positioning In Polarized Cells, Arkaprovo Ghosal, Padmanabhan Seshaiyar Dr., Adriana Dawes Dr., General Genomics Inc.

Annual Symposium on Biomathematics and Ecology Education and Research

No abstract provided.

Wire Electrical Discharge Machining Of Aisi304 And Aisi316 Alloys: A Comparative Assessment Of Machining Responses, Empirical Modeling And Multi-Objective Optimization, Mona Aboueleaz, Noha Naeim, Islam Abdelgaliel, Mohamed Aly, Ahmed Elkaseer

Mechanical Engineering

This research investigates the multi-response of both material removal rate (MRR) and surface roughness (Ra) for the wire electrical discharge machining (WEDM) of two stainless steel alloys: AISI 304 and AISI 316. Experimental results are utilized to compare the machining responses obtained for AISI 316 with those obtained for AISI 304, as previously reported in the literature. The experimental work is conducted through a full factorial experimental design of five running parameters with different levels: applied voltage, transverse feed, pulse-on/pulse-off times and current intensity. The machined workpieces are analyzed using an image processing technique in order to evaluate the size …

Thermo-Mechanical Instabilities In Next-Generation Friction Materials In High-Speed Sliding Systems, Kingsford Koranteng

Electronic Theses and Dissertations

For centuries, the manufacturing industry has incorporated metals like copper into friction materials to enhance thermal properties and minimize thermo-mechanical instabilities (TMI) in high-speed sliding systems. Unfortunately, these metals have adverse environmental effects due to the emission of hazardous particulate matter. As a result, there is a growing movement towards adopting next-generation friction materials as an alternative solution.

The study begins by conducting experimental and numerical investigations to examine the instabilities found in metal-based friction materials. The primary objective is to utilize the insights gained from the investigations to computationally explore effective strategies for mitigating various instabilities that may arise …

Molecular Dynamics Study Of Characterization In Metal-Free Friction Materials, Yizhan Zhang

Electronic Theses and Dissertations

Metallic friction materials currently used in industry may adversely impact the environment. Substitutions for metals in friction materials, on the other hand, can introduce operational safety issues and other unforeseeable issues such as thermal-mechanical instabilities and insufficient strength. In view of it, this dissertation focuses on developing different kinds of materials from simple structure to complex structure and evaluating the material properties with the assistance of molecular dynamics (MD) tools at the nano scale.

First, the concept of the contacted surfaces in friction at the atomic scale was introduced in order to get accurate understanding of the friction process compared …

Design And Scale Model Of Wave Generator For The Testing Of Wave Energy Conversion Devices, Amanda Olla

Master's Theses

As the climate crisis draws more concern, research and development in wave energy as a renewable energy source has increased. Devices such as wave energy converters (WECs) are being researched, tested, and implemented to make wave energy a competitive power source. Testing of these devices is limited due to environmental concerns such as weather, location, and other issues. WECs require testing in a marine environment, however, performing testing in the actual environment may be difficult due to weather, access, mounting, and other issues. To eliminate environmental unknowns from testing, a wave simulator device can mimic wave behavior without the need …

Mems Cantilever Biosensors Driven By Fringe Effect: Voltage-Amplitude Response Of Parametric Resonance, Miguel A. Martinez, Dumitru I. Caruntu

Mechanical Engineering Faculty Publications

This paper deals with voltage-amplitude response of fringing field/effect actuated micro-electromechanical system (MEMS) cantilever beam resonator biosensors at parametric resonance. The system consists of a flexible electrode (cantilever beam) and a fixed electrode (ground plate) in parallel, connected through an AC voltage source. The electrostatic force induced is due to the parallel-plate capacitance, which is directly related to the overlapping area of the two electrodes (Palmer’s Formula). In addition, fringing field electrostatic actuation must be accounted for. This is due to the bending of electric field lines from the ground plate to the top and side walls of the cantilever …

Heat Transfer Performance Of Single-Phase Circular Heat Sink With Micro Pin-Fin, Mouza Abdulla Al Shamsi

Theses

This thesis presents a numerical study of laminar forced convection in a novel design of a microscale single phase water cooled circular heat sink with pin fins developed and analyzed to serve as a miniaturized cooling system. The developed heat sink in this study aims to achieve efficient heat dissipation from high electronics integration that generates high heat flux and non-uniform temperature distribution, which leads to the reduction of life and reliability of electronic devices.

Numerical analysis of ten different configurations of the circular heat sink has been carried out for the heat flux of 100 W/cm2 at range of …

Searching For Unknown Material Properties For Am Simulations, Aaron Flood, Rachel Boillat, Sriram Praneeth Isanaka, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Additive manufacturing (AM) simulations are effective for materials that are well characterized and published; however, for newer or proprietary materials, they cannot provide accurate results due to the lack of knowledge of the material properties. This work demonstrates the process of the application of mathematical search algorithms to develop an optimized material dataset which results in accurate simulations for the laser directed energy deposition (DED) process. This was performed by first using a well-characterized material, Ti-64, to show the error in the predicted melt pool was accurate, and the error was found to be less than two resolution steps. Then, …

Development Of Guidance, Navigation, And Control Systems For Multi-Spacecraft Assembly In Proximity Operations, Mohammed Ayman Atallah

Theses

This thesis presents the development of Guidance, Navigation, and Control (GNC) algorithms for multi-spacecraft assembly in proximity operations. A 3-DOF mathematical model of spacecraft relative translational motion is derived using the Euler-Lagrange method. Additionally, a 6-DOF mathematical model of spacecraft relative translational and rotational motion is derived using the twistor method, with consideration for the kinematic coupling effect. A new Linear Time-Invariant (LTI) model is developed based on the twistor model, which is utilized in the design of the GNC systems. Both LTI Model Predictive Control (MPC) and Linear Time-Varying (LTV) MPC algorithms are employed to develop Guidance and Control …

Amplitude-Voltage Response Of Parametric Resonance Of Electrostatically Actuated Circular Membranes, Marcos Alipi, Dumitru I. Caruntu

Mechanical Engineering Faculty Publications

This paper deals with the amplitude-voltage response of parametric resonance of electrostatically actuated MEMS circular membranes resonator for sensing applications. The system consists of a flexible circular membrane over a parallel ground plate. A soft AC voltage is applied between the MEMS membrane and ground plate to actuate the membrane near its first natural frequency. Two methods of investigation are used in this research, namely the method of multiple scales (MMS), and the reduced order model (ROM). These methods were used to solve for the voltage response of the MEMS analytically and numerically. This work also reports the effects the …

Aerodynamic & Aeroacoustic Performance Of Wind Turbine Blades Featuring Enhanced Flow-Control, Md Zishan Akhter

Dissertations

Wind energy, being one of the cleanest and most sustainable sources, has undergone remarkable growth in recent years due to advancements in aerodynamics and increased power output. The research community is actively pursuing the development of cutting-edge solutions to further optimize wind turbine technology, ensuring its maximum efficiency and revolutionizing the landscape of wind power.
/="/">This research aims to design and develop flow-control devices for wind turbine blades, employing both active and passive control mechanisms, namely morphing trailing-edge and slot-profile, respectively. The objective is to enhance wind turbine performance across a wide range of wind speeds. The morphing trailing-edge …

Impact Of Silicon Ion Irradiation On Aluminum Nitride-Transduced Microelectromechanical Resonators, David D. Lynes, Joshua Young, Eric Lang, Hengky Chandrahalim

Faculty Publications

Microelectromechanical systems (MEMS) resonators use is widespread, from electronic filters and oscillators to physical sensors such as accelerometers and gyroscopes. These devices' ubiquity, small size, and low power consumption make them ideal for use in systems such as CubeSats, micro aerial vehicles, autonomous underwater vehicles, and micro-robots operating in radiation environments. Radiation's interaction with materials manifests as atomic displacement and ionization, resulting in mechanical and electronic property changes, photocurrents, and charge buildup. This study examines silicon (Si) ion irradiation's interaction with piezoelectrically transduced MEMS resonators. Furthermore, the effect of adding a dielectric silicon oxide (SiO₂) thin film is …

A Generalized Machine Learning-Based Classifier Considering Cost-Effective Features For Automated Fault Detection And Diagnosis (Afdd) Of Packaged Rooftop Units, Md Rasel Uddin

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Packaged rooftop units (RTUs) are widely used for space conditioning in commercial buildings and manufacturing facilities. The typical soft faults related to RTUs degrade the system's performance in terms of cooling capacity, power consumption, and Coefficient of Performance (COP), detrimentally affecting both the equipment and energy consumption and the environment. Previous research in soft fault detection for rooftop units lacked classifier validation using lab and field data, developing a generalizable algorithm, and analyzing its performance across varying fault intensities.

Using a simulated data library for multiple rooftop units, this study proposes a machine-learning classifier with a reduced set of 9 …

Digital Twins Of The Living Knee: From Measurements To Model, Thor Erik Andreassen

Electronic Theses and Dissertations

Modern medicine has dramatically improved the lives of many. In orthopaedics, robotic surgery has given clinicians superior accuracy when performing interventions over conventional methods. Nevertheless, while these and many other methods are available to ensure treatments are performed successfully, far fewer methods exist to predict the proper treatment option for a given person. Clinicians are forced to categorize individuals, choosing the best treatment on “average.” However, many individuals differ significantly from the “average” person, for which many of these treatments are designed. Going forward, a method of testing, evaluating, and predicting different treatment options' short- and long-term effects on an …

Potential Roles Of Vessel Traffic Services (Vts) In Maritime Decarbonization, Suleiman Mustapha Bunza

World Maritime University Dissertations

No abstract provided.

Application Of Wind Propulsion In The Existing Fleet Of The Caspian Sea Using Real Wind Data, Mahmud Suleymanli

World Maritime University Dissertations

No abstract provided.