Engineering Science and Materials Commons^™

Quantifying The Effect Of Initial Molecular Weight Distribution On The Degradation Of Linear Polyethylene At High Temperatures Using Dissipative Particle Dynamics, Cassandra L. Simpson

All Theses

Polyolefins are the primary contributors to greenhouse gas emissions and supply chain energy requirements with respect to other commodity polymers. In order to explore more efficient methods for recycling and upcycling these plastics, it is important to consider the kinetics of polymer fragments during the degradation process to more accurately reflect experimental outcomes. The molecular weight distribution of synthetic polymers is an important factor to consider when synthesizing, processing, and manufacturing industrial plastics. The breadth of this distribution, or dispersity, is determined by the ratio of the weight average molecular weight to the number average molecular weight, and is correlated …

Mechanical Characterization Of M Plane (10-10) And C Plane (0001) Gallium Nitride Semiconductors Via Spherical Nanoindentation, Daniela Alejandra Duarte

Open Access Theses & Dissertations

Gallium nitride's (GaN) mechanical characterization is essential for evaluating its performance and long-term dependability, especially when subjected to mechanical stress and irradiation. The design and optimization of GaN-based devices, which are extensively employed in high-power electronics and optoelectronics, depend on an understanding of these characteristics. Mechanical characterization allows for the evaluation of key characteristics, including stress distributions, representing the spatial variation of internal stresses under applied loading, and pop-in events, which correspond to abrupt displacements associated with the onset of dislocation nucleation and slip. These features are essential for understanding the anisotropic (direction-dependent) response of the material to external forces …

Application Of Distributed Fiber Optic Sensing (Dfos) For Monitoring Asphalt Pavement Strains Under Accelerated Loading Conditions, Sebastian Morales

Open Access Theses & Dissertations

This thesis presents a study on the application of Distributed Fiber Optic Sensing (DFOS) technology for detecting pavement's strain response with high spatial resolution. Using a Rayleigh-based optical frequency domain reflectometry (OFDR) system, DFOS sensors were calibrated and embedded in full-scale asphalt slabs subjected to accelerated loading using a Model Mobile Load Simulator 3 (MMLS3). Calibration of the DFOS sensors was conducted using a three-point bending flexural test with known load conditions and reference strain gauges to validate theoretical and numerical models. The results demonstrate DFOS's capability to detect pavement response under static and dynamic loading, as well as changes …

Laser Scan Path Design For Controlled Microstructure In Additive Manufacturing With Integrated Reduced-Order Phase-Field Modeling And Deep Reinforcement Learning, Augustine Twumasi

Open Access Theses & Dissertations

Laser Powder Bed Fusion (L-PBF) is a well-established additive manufacturing technique for fabricating intricate metal components with exceptional precision. A significant challenge in L-PBF is the formation of complex microstructures that influence final material properties. We propose a physics-guided, machine learning-aided approach to optimize scan paths for desired microstructure outcomes, such as equiaxed grains. We employed a phase-field method (PFM) to model the evolution of the crystalline grain structure. To reduce computational costs, we trained a surrogate machine learning model, a 3D U-Net convolutional neural network, using single-track phase-field simulations with varying laser powers to predict crystalline grain orientations based …

Advancing Real-World Implementation Of The Well Optimized Linear Finder (Wolf) High-Speed Atmospheric Turbulence Compensation Method, Timothy Evan Coon

Theses and Dissertations

This dissertation advances the real-world implementation of the Well Optimized Linear Finder (WOLF) method for high-speed Atmospheric Turbulence Compensation (ATC). Atmospheric turbulence introduces phase aberrations into optical wavefronts and degrades image quality in terrestrial imaging systems. Traditional phase diversity methods are computationally intensive and poorly suited to real-time operation. The WOLF method addresses these limitations through a novel, point-wise formulation of the optical transfer function (OTF) as a structured autocorrelation of the generalized pupil function (GPF). This formulation enables the estimation of phase aberrations at individual spatial coordinates with distributed computational complexity.

The research begins by developing a MATLAB-based simulation …

Shape Memory Behavior In Medium To High Entropy Shape Memory Alloys: Design, Prediction, And Experimental Analysis, Hatim Raji

Theses and Dissertations

This dissertation provides a data-driven system integrating synthetic data generation and machine learning (ML) techniques to create multicomponent SMA compositions with specific transformation temperatures (TTs). Models were trained to represent the nonlinear dependencies influencing martensitic transformation behavior by using elemental, thermodynamic, and process-related aspects. The capacity of the ML models on medium entropy NiTiHfPd and high entropy NiTiHfZrCu systems accuracy was confirmed by experimental validation showing TTs closely matched with model outputs.

Development Of Power Management On Unmanned Surface Vehicles To Measure Battery Voltage And Power, Diana Alia, Henna Nurdiansari, Akhmad Kasan Gupron, Amelia Greacy Talenta Siregar

Journal of Mechanical Engineering Science and Technology (JMEST)

This research focuses on designing an electrical system for unmanned surface vehicles (USV) to ensure optimal performance during survey operations. This USV ship is a catamaran-type ship with a Sonar Deeper depth sensor to know the depth of the water and is equipped with long range (LoRa) as a data transmitter. The USV electrical system design incorporates the use of a 4050 mAh 11.1 V LiPo battery and an iMAX B6AC charger, with evaluations covering battery charging, power consumption, and voltage stability. The trials showed that the battery supported the operation of the USV for approximately 47.8 minutes at a …

Utilization Of Biomass From Kerai Payung Trees And Waste Paper Through Pyrolysis Technology To Support The Zero-Waste Concept, Anggita Putri Indadari, Nurfa Anisa, Asih Budi Santoso

Journal of Mechanical Engineering Science and Technology (JMEST)

Wisnuwardhana University is a private institution with a green campus environment surrounded by Kerai Payung trees. This environment produces organic waste from trees and inorganic waste such as used paper from campus activities. This study aims to achieve zero-waste processing by using pyrolysis technology to process campus waste, ensuring minimal residue. The experimental method involves comparing waste processing outcomes between conventional combustion and pyrolysis, the data was analyzed by comparing the results of pyrolysis with conventional combustion. The results of biochar from the pyrolysis process of used paper, Kerai Payung leaves, and nagging Kerai Payung tree are 76 g, 250 …

Dynamic Analysis And Fatigue Life Evaluation Of Single Herringbone Planetary Gear System With Crack Fault, Dongping Sheng, Jie Yang, Chun Su

Journal of Mechanical Engineering Science and Technology (JMEST)

The herringbone planetary gear transmission is widely used due to its exquisite compact structure, excellent load-bearing capacity, and stable transmission characteristics. However, root crack is one of the most common failure modes of gears. A cracked herringbone planetary gear system is taken as research object. The sun gear with crack fault is studied from the aspect of modal and transient dynamic analysis, and the related results are compared with the healthy gear. Based on the transient dynamic analysis of the herringbone teeth with cracks, a fatigue life evaluation is conducted. Firstly, the results show that no significant difference between the …

Investigation Of The Influence Of Warhead Shape And Type Of Missile Weapon Material Counter-Training Tank Weapons Simulation Approach, Transisma Budiarta, Haris Puspito Buwono, Radhi Nurvian Amrullah

Journal of Mechanical Engineering Science and Technology (JMEST)

This study analyzes the effect of warhead shape and material variations on pressure, temperature, and lift on training missiles using CAD-based simulation methods. The variations of warhead shapes tested include flat, flat radius, and tapered, while the materials used are rubber, ABS, and PE. The simulation results show that the tapered warhead shape with PE material produces the lowest pressure (50.3 MPa) due to more efficient pressure release and low friction properties. Conversely, the Flat shape produces the highest pressure (69.1 MPa) on all materials due to flow stagnation. In terms of temperature, the Flat Radius warhead with PE and …

Investigation Of Drag Force And Downforce On Two Racing Motorcycles In Slipstream Conditions, Muhamad Hanifudin, Gaguk Jatisukamto, Mahros Darsin, Muh. Nurkoyim Kustanto, Azmi Saleh, Suprihadi Prasetyono, Catur Suko Sarwono

Journal of Mechanical Engineering Science and Technology (JMEST)

The performance of modern racing motorcycles is greatly influenced by their aerodynamics. Slipstreaming occurs during a race when a rider closely follows another, especially on a straight track. The effect can reduce aerodynamic drag and increase the overall speed of the rider behind. This study investigates the aerodynamic effects of slipstreaming on a racing motorcycle using computational fluid dynamics. This study also considers its effect on both drag force and downforce, which affects motorcycle stability. A 3D CAD model of a racing motorcycle and a rider in a crouching position was used as the object of research. CFD simulations were …

Characterization Of Curcumin As A Coating Material For Polymer-Free Stents Interms Of Morphology And Release, Ameliyana R.S.P.A. Yani, Muhammad Kusumawan Herliansyah

Journal of Mechanical Engineering Science and Technology (JMEST)

The use of bare metal stents over the long term often leads to the re-narrowing of blood vessels, prompting a shift to drug-eluting stents (DES). However, the use of polymers in DES has been known to trigger inflammation and thrombosis in the arteries. As an alternative, polymer-free drug-eluting stents (PF-DES) have emerged as a safer option. In this study, curcumin was selected as the primary coating material for PFDES using the electrophoretic deposition method. The effects of varying curcumin concentrations (125 µg/ml, 250 µg/ml, and 500 µg/ml) were examined to understand their impact on deposition morphology, coating weight, chemical bonding …

Influence Of Different Nanoparticles On Thermophysical Properties And Wear Resistance Of Corn Oil-Based Cutting Fluid In Mql-Cnc Milling Machining, M Nuril Anwar Habiby, Poppy Puspitasari, Aminnudin Aminnudin, Diki Dwi Pramono, Ahmad Atif Fikri, Mariyam Jameelah Ghazali

Journal of Mechanical Engineering Science and Technology (JMEST)

Vegetable oil-based cutting fluids have emerged as a promising innovation in machining operations, supporting the advancement of sustainable and eco-friendly manufacturing practices. This study delves into the development of a biolubricant derived from corn oil, enriched with 0.15% mass fractions of various nanoparticles, including calcium carbonate (CaCO3), copper oxide (CuO), and multi-walled carbon nanotubes (MWCNT). These nano-cutting fluids were applied through the Minimum Quantity Lubrication (MQL) method during CNC milling of AISI 1045 steel. The investigation focused on evaluating thermophysical properties, including density, thermal conductivity, and dynamic viscosity, as well as tool wear performance. The results demonstrated that CuO nanoparticles …

Impact Of Print Speed And Nozzle Temperature On Tensile Strength Of 3d Printed Abs For Permanent Magnet Turbine Systems, Wirawan Wirawan, Hilmi Iman Firmansyah, Satworo Adiwidodo, Mohammad Sukri Mustapa

Journal of Mechanical Engineering Science and Technology (JMEST)

Operational parameters must be integrated into turbine systems' main components, which are determined by turbine systems' functional requirements. The need for producing component designs more effectively raises the possibility of using additive manufacturing. The study focuses on the optimization of the mechanical properties of the principal components of magnetic turbines manufactured with 3D printers using Acrylonitrile Butadiene Styrene (ABS), by changing the temperature and speed of the nozzle. The approach consisted of modeling a standard test piece in CAD software and producing ABS-based test pieces using a 3D printer with print speeds of 50, 70, 90, and 110 mm/s and …

Performance Analysis Of Alkaline Fuel Cell With Variation Of Potassium Hydroxide Concentration In Electrolyte Solution, Mohammad Rifqy Alfariz, Nasrul Ilminnafik, Dwi Djumhariyanto, Intan Hardiatama, Muhammad Khadafi Ibnu, Raafi Aditya Nugraha, Domingos De Sousa Freitas

Journal of Mechanical Engineering Science and Technology (JMEST)

Alkaline Fuel Cell (AFC) is a green energy conversion tool that converts chemical energy into electrical energy through electrochemical reactions. This research aims to analyze the effect of potassium hydroxide (KOH) concentration variation in electrolyte solution on the AFC performance, using nickel and manganese catalysts. The research methods include experiments using various KOH concentrations to determine the optimal concentration to produce the best AFC performance. The voltage and current produced are measured, as well as the calculation of the electrical power and efficiency of the AFC. The results showed that KOH concentration has a significant influence on the performance of …

Toolpath Motion Strategy And Feed Rate In Cnc Milling On Energy Consumption Of Machining Process, Luqman Dwi Saputra, Eko Yudiyanto

Journal of Mechanical Engineering Science and Technology (JMEST)

The use of CNC milling machines to produce components, especially aluminum brackets used for automotive, is one of the advances in the industrial field. The use of CNC milling machines has the advantage of producing processes with speed accuracy, and better workpiece quality than conventional machines. This research investigates energy consumption in the CNC milling process by varying the toolpath motion strategies—Zigzag, Constant Overlap Spiral, Parallel Spiral, and Parallel Spiral Clean Corners—as well as feed rates of 700 mm/min, 800 mm/min, 900 mm/min, and 1000 mm/min. The goal is to find out the best parameters for using energy in the …

Boiling Heat Transfer Coefficient And Critical Heat Flux On Conical Cylindrical Copper Under Surface Modification, Muhammad Dimyati Nashrullah, Andi Sanata, Imam Solahuddin, Nasrul Ilminnafik, Indro Pranoto, Adhika Widyaparaga

Journal of Mechanical Engineering Science and Technology (JMEST)

This study examined how surface roughness and nanoceramic coating, influences the boiling heat transfer coefficient (BHTC) and critical heat flux (CHF) of a conical cylindrical copper test specimen. Three test specimens exhibiting surface roughness of 0.22 µm, 0.14 µm, and 0.04 µm were analyzed for comparison. Two additional test specimens were treated with nanoceramic coatings utilizing silicon carbide as the base material: one specimen received a single-layer coating and the second was applied with a double-layer coating. The behavior of the bubbles was closely observed with a high-speed camera to deepen the analysis. The experimental results showed that the test …

Development Of Adjustable Static Test Equipment For Below-Knee Prosthetic Feet: A Case Study, Firmansyah Hafizh Rizal Nurrokhim, Fauzan Raka Mawandi, Puspa Dinda Safitri, Imam Mahmudah, Dwiky Mirnanda, Ndaru Adyono, Wahyu Dwi Lestari

Journal of Mechanical Engineering Science and Technology (JMEST)

The high prevalence of physical disabilities in Indonesia, particularly among the productive-age population, highlights the urgent need for advancements in prosthetic technology. While local fabricators have begun producing prosthetic feet, the lack of standardized testing procedures compromises safety and performance. This study addresses that gap by developing an adjustable static testing device tailored for below-knee prosthetic feet, focusing on keel and heel tests to evaluate mechanical performance. The device includes a jig-fixture platform adjustable to 8° and 15° for heel and keel tests, respectively. It applies a 1230 N load based on AOPA standards and integrates load and displacement sensors …

Performance Of Rice Grain Conveyor Vacuum Blower With Variations In The Number And Shape Of Impeller Angles, Dedi Suwandi, Agus Sifa, Tito Endramawan, Kasni Sumeru, Ismail Wellid

Journal of Mechanical Engineering Science and Technology (JMEST)

Separating rice and bran, moving rice to storage, and other processes related to moving grain or rice. In the modern rice milling industry, the process of transferring grain material already uses a pneumatic conveying system; a vacuum blower system for transferring grain is needed when milling grain to become rice. The research method used to obtain the shape of a vacuum blower with strong inlet suction power and outlet thrust is carried out by Computational Fluid Dynamics simulation and testing several types and variations in the number of blades. Simulation of forward curved blade type impellers, backward curved blade, and …

Characterization Of Bamboo Petung Fiber Reinforced Composites With Environmentally Friendly Enzymes, Rudianto Raharjo, Teguh Dwi Widodo, Redi Bintarto, Fikrul Akbar Alamsyah

Journal of Mechanical Engineering Science and Technology (JMEST)

Natural fiber composites are a good choice for many businesses uses because of their better mechanical properties and are friendly environment. Researchers are currently looking into bamboo petung fiber (BPF) and epoxy composites as alternative to synthetic fibers and products made from petroleum. This study's goal is to improve the overall performance of these composites while reducing the need for non-organic materials. This study used the various concentration of bromelain enzyme in BPF to changes the mechanical and physical properties of epoxy composites made from BPF. Composites were characterized the mechanical properties including tensile strength using tensile tester, impact strength …