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Enhancing The Design Of Strained Superlattice Gallium Arsenide Based Photocathodes With Distributed Bragg Reflector, Adam D. A. Masters

Electrical & Computer Engineering Theses & Dissertations

Particle accelerators play a crucial role in our understanding of matter and the universe and have numerous practical applications in various fields. These devices enable scientists to examine the smallest components of matter, study the forces that govern their interactions, and probe conditions from the early universe. Moreover, accelerators are valuable in medicine, industry, and research, enhancing imaging methods, cancer therapies, and manufacturing techniques. As the experiments conducted at these facilities evolve and require higher precision, improved particle sources must continue to advance to keep up with their requirements. To do that, we enhanced the design of spin polarized electron …

Dealuminated Metakaolin In Supplementary Cementitious Material And Alkali-Activated Systems: A Review, Amany G. Micheal Prof., Mostafa Adel Elsebaei Eng., Maria Mavroulidou Prof., Maria Centeno Assoc. Prof., Rabee Shamass Senior Lec., Ottavia Rispolio Mrs.

Architectural Engineering

This paper presents a comprehensive review of dealuminated metakaolin (DK), a hazardous industrial by-product generated by the aluminium sulphate (alum) industry and evaluates its potential as a component in cementitious systems for the partial or full replacement of Portland cement (PC). Positioned within the context of waste valorisation in concrete, the review aims to establish a critical understanding of DK formation, properties, and reactivity, particularly its pozzolanic potential, to assess its suitability for use as a supplementary cementitious material (SCM), or as a precursor in alkali-activated cement (AAC) systems for concrete. A systematic methodology is used to extract and synthesise …

Designing Self-Healable Aromatic Copolymers And Olefinic Composites, Samruddhi Yashwant Gaikwad

All Dissertations

Self-healing polymers capable of recovering from mechanical damage are promising materials for advanced applications, especially those involving mechanical and/or physical fatigue. In these studies, we have developed techniques to achieve autonomous self-healing in commodity Styrene/n-butyl acrylate copolymers. The mechanism of self-healing in the designed polymers involves inter-and/or intrachain non-covalent interactions between π-cloud and polar linkages of acrylic nBA in random/preferentially alternating copolymers. A combination of spectroscopic tools, thermo-mechanical analysis, and molecular dynamics (MD) simulations has been used to elucidate the mechanism of self-healing. These studies further show the incorporation of dipolar C-F groups to understand the effect of having fluorinated …

Investigation Of Solid-State Reactive Sintering And Rapid Laser Reactive Sintering For Al-Doped Li7la3zr2o12 Solid-State Electrolyte, Aaron Santomauro

All Dissertations

As a society, we’ve exhausted an extreme amount of fossil fuels and put an overwhelming strain on Earth’s natural resources. From this, it is critical to think about the successful future of our planet and ourselves by developing energy devices such as all-solid-state lithium-ion batteries (ASSLIBs). These devices offer a greener and more efficient alternative to power our daily lives, such as electric vehicles (EVs), portable electronics, medical devices, grid-scale energy storage, and aerospace/aviation. ASSLIBs are an excellent alternative to liquid-state batteries, which pose dangerous safety concerns (e.g., flammability, electrolyte leakage, etc.). These ASSLIBs are known to have generally high …

Advancing Lithium-Ion Batteries Through Exploration Of Novel Physico-Chemical Phenomena, Peshal Karki

All Dissertations

Lithium-ion batteries (LIBs) power a wide range of modern devices, from smartphones to electric vehicles. This dissertation integrates materials characterization and electrochemical testing to develop novel Si-based electrode materials, investigate separator effects, and improve electrochemical impedance spectroscopy (EIS) modeling. First, I synthesized Si@CC composites using bio-based carbon sources and discovered a novel in situ disorder reduction in the amorphous carbon cloud during cycling, attributed to Si volume fluctuations and mesoporous carbon structure, which enhanced capacity retention. A binder-free electrode (Si@CC@BP) using bucky paper further improved gravimetric and areal capacities while reducing weight and manufacturing complexity.

Next, I investigated how separator …

Synthesis And Characterization Of Magnetic Nanoparticles To Study Effective Magnetic Anisotropy For Biomedical And Catalytic Applications, Alexander Malaj

All Dissertations

This dissertation focuses on understanding how to tune the magnetic properties of nanoparticles through controlling the effective magnetic anisotropy (Keff), which is a key variable in determining a nanoparticle’s Néel relaxation time, which will dictate its magnetic behavior in various applications. In this work, magnetocrystalline anisotropy is tuned by synthesizing tri-metallic substituted ferrite (Fe3-x-yMnxCoyO4) nanoparticles with specific metallic compositions that were informed by computer simulations using density functional theory (DFT) to target magnetocrystalline anisotropy values. A drip synthesis was used to control the size and composition of the tri-metallic ferrites, which were revealed to be monodisperse and compositionally mixed by …

Material Extrusion 3d Printing Of Metal Alloy: Material, Methods And Application., Sihan Zhang

Electronic Theses and Dissertations

Material extrusion (MEX) additive manufacturing presents a promising pathway for producing metal components with complex geometries while avoiding the safety hazards associated with loose powder handling in conventional metal additive manufacturing processes. This dissertation investigates the development and optimization of MEX processes for aluminum alloys, addressing critical challenges in feedstock formulation, printing parameter optimization, and post-processing strategies. Three distinct approaches were explored to advance the capabilities of aluminum MEX: filament-based processing of 6061 aluminum, paste-based extrusion of 6061 aluminum, and development of a novel aluminum-magnesium-tin alloy system for space manufacturing applications. The filament-based approach successfully demonstrated the production of 6061 …

Ferroelectricity And Multiferroicity In Ultrathin Films Of Unconventional Transition Metal Oxide, Xin Li

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

Ferroic orders of transition metal oxides, such as ferroelectricity and ferromagnetism, are determined by the intercoupling between spin, charge, lattice. Consequently, ferroic epitaxial thin films have attracted wide interest due to the profuse novel phenomena and the great application potentials for modern electronics. However, the mainstream of the study for transition metal oxides has focused on perovskite structure, limiting the understanding and discovery of novel phenomena associate with ferroic orders. In this thesis, the epitaxial films of hexagonal rare-earth ferrites (h-RFeO₃) and fluorite-structure hafnia oxide (HfO₂) are studied comprehensively, providing new experimental and theoretic …

Feasibility Study On Using Blue Clay As A Supplementary Cementitious Material (Scm)., Clark Lemon

Master of Engineering Theses

An effective strategy for reducing CO₂ emissions in the global cement industry is replacing a percentage of cement with supplementary cementitious materials (SCMs). As the availability of conventional SCMs such as fly ash and slag is decreasing, alternative SCMs such as calcined clays have been studied for their use as effective pozzolans. The present work investigates the feasibility of using a waste product from the quarrying industry known as blue clay as a viable SCM. It is composed of multiple clay minerals, predominantly muscovite. Raw and calcined at four temperatures (500, 650, 800, and 950°C), blue clay was analyzed …

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.

Synthesis, Structural Characterization And Optical Studies Of Silver-Indium-(Zinc)-Chalcogenide Fluorescent Quantum Dots, Sujal Acharya

Graduate Theses and Dissertations

Developing a non-toxic, high-performance fluorescent nanomaterial is crucial for overcoming the environmental and health restrictions of current cadmium, and lead based quantum dots (QDs), which limit the application of quantum dots in optoelectronics and bioimaging. In this thesis, we synthesized environmentally friendly AgInS2 QDs by a colloidal method, systematically altering the In/Ag precursor ratio from 2 to 6 to study the impact on their optical and photophysical properties. Our goals were to find the optimal stoichiometry for maximum quantum efficiency and stability. We also investigated further improving optical and photophysical properties through shelling with ZnS. The emission spectra appeared broad, …

Polymer-Enhanced Nanopore Sensing, Eugene Gyasi Agyemang

Graduate Theses and Dissertations

The resistive pulse technique characterizes single analytes by detecting fluctuations in the ion current as they pass through a narrow orifice connecting two electrolyte-filled chambers, each containing a single electrode. The amplitude, shape, frequency, and duration of these fluctuations primarily provide information about the analyte’s size, shape, concentration, and net surface charge, respectively. One configuration for resistive pulse measurements is of an electrolyte-filled nanopipette immersed in a bath, where the nanopipette tip acts as the nanoscale orifice. It was previously shown that incorporating the large quantities polymer polyethylene glycol (PEG 8K, 50% w/v) into the external electrolyte bath dramatically enhanced …

Discovering And Designing Novel Perovskite Photovoltaic Materials Via Machine Learning, Junyeong Ahn

Discovery Undergraduate Interdisciplinary Research Internship

Perovskite semiconductors are promising materials for high-efficiency photovoltaics due to their outstanding optoelectronic properties, emerging as a sustainable energy source through solar cell applications. Perovskites with the ABX₃ composition (A, B = metal or organic cations with varying oxidation states; X = chalcogen or halogen anions) have gained interest for their excellent phase stability and compositional tunability. However, combinatorial possibilities arising from the many choices of A, B, and X site species, and their respective mixing fractions, a large number of possible ABX₃ perovskites remain undiscovered. In this work, we used machine learning (ML) methods to design new stable and …

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 …

Effect Of Various Canopy Shapes On The Drag Coefficient Of Pickup Trucks, Khairil Anwar, Muhammad Syaiful Fadly, Muhammad Wahyu Hermanto

Journal of Mechanical Engineering Science and Technology (JMEST)

The aerodynamic performance of light commercial vehicles, such as the Suzuki Carry, plays a crucial role in their fuel economy and road stability. One typical add-on, a canopy, often changes that airflow and, as a result, alters the drag acting on the vehicle. In this study, three different canopy shapes, flat, curved, and triangular, were examined to understand how each one affects the drag coefficient (Cd). To investigate this, both wind tunnel trials and CFD runs were conducted to track the airflow and measure any changes in drag with greater detail. For reference, the exact vehicle without a canopy was …

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 …

Steam Supply Evaluation For Carbon Capture And Storage In A Subcritical Coal-Fired Power Plant, Veri Hendrayawan, Anggit Raksajati, Sanggono Adisasmito, Firman Bagja Juangsa

Journal of Mechanical Engineering Science and Technology (JMEST)

The aim of this study is to analyze the implementation of carbon capture and storage (CCS) in coal-fired power plants (CFPP) in Indonesia by determining the reboiler energy demand through steam source analysis. The study uses a representative 3×330 MW subcritical coal-fired power plant (CFPP), with an emission intensity of 1.02 tCO₂/MWh and flue gas CO₂ concentration of 13.8%. CCS modeling shows the reboiler requires about 2.9×10⁹ kJ/h energy, supplied by steam extracted from the plant’s steam cycle. A steam cycle model was developed to evaluate the impact of steam extraction. Potential tapping points analyzed include main steam, cold reheat, …

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 …

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 …

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 …

Multiple Input–Single Output (Miso) Framework For Low Velocity Impact Response Of Hybrid Gongronema Latifolium/S-Glass Fibre Epoxy Composites, Christian Emeka Okafor, Peter Chukwuemeka Ugwu, Godspower Onyekachukwu Ekwueme, Nürettin Akçakale, Emmanuel Chukwudi Nwanna

Journal of Mechanical Engineering Science and Technology (JMEST)

Sustainable composites are vital for impact-critical aerospace, automotive, and defense applications. This study used Multiple Input–Single Output (MISO) experimental approach to assess how hybrid ratio, mass fraction, and fiber orientation influence the low-velocity impact behavior of Gongronema/S-glass epoxy composites. Gongronema fibers and S-glass were combined with ER-F292 epoxy and molded into ASTMstandard samples. Charpy impact tests measured energy absorption. A 60-run design evaluated input variable combinations, and Multiple Linear Regression identified significant predictors using p-values and confidence intervals. Results showed that the mean values for hybridization ratio, mass fraction, fiber orientation, and low velocity impact were (2.50), (27.79%), (67.90°), and …