Engineering Science and Materials Commons^™

Intrinsic, Doped And Alloyed Gallium Oxide Films For Optoelectronics, Francelia Sanchez Escobar

Open Access Theses & Dissertations

Due to the impressive advancement of present technology and increasing energy consumption, there is increasing demand for energy-efficient multifunctional devices based on low-cost, eco-friendly material systems. Gallium oxide (Ga2O3) is an emerging semiconductor with potential for the next generation of power electronics and optoelectronic devices due to its ultra-wide bandgap of 4.8 eV and high theoretical breakdown voltage of 8 MV/cm among other intrinsic properties. Some of the possible applications of β-Ga2O3 include ultra-violet (UV) solar blind photodetectors, field effect transistors, solar cells, and chemical sensors. However, to utilize its full potential, understanding the mechanistic aspects of thin film growth …

Assessing Khumbu Region Glaciers Mass Balance Change Using Geospatial Techniques From 2012 To 2024, Yashvi Jagatbhai Shah

Electronic Theses, Projects, and Dissertations

The glaciers in the Hindu Kush Himalaya are critical for sustaining the water supply of South Asia's major rivers, upon which over 230 million people, both in the mountainous regions and lowland areas, depend. Climate change is driving rapid glaciers melt near the summit of Mount Everest, located at an elevation of approximately 7,906 meters (25,938 feet). This has resulted in glacier thinning occurring up to 80 times faster than the original ice formation. However, due to their disposition in a complex topographic setting and inaccessible terrain, continuous glacier observations pose significant challenges.

This study evaluated the mass balance of …

Greek Key-Inspired Fractal Metamaterials With Enhanced Flexibility And Energy Absorption., Zhennan Zhang

Electronic Theses and Dissertations

Architected materials with intricate three-dimensional (3D) geometries offer unique properties and functionalities but face challenges in manufacturing costs and complexity. This research explores the integration of simple 2D Greek Key-inspired lattices into fractal designs to achieve exceptional mechanical performance. Using 3D printing and kerfing, these fractal structures demonstrate enhanced flexibility and energy absorption capabilities. Through three-point bending and in-plane tensile tests, the 2D fractal lattices exhibited a 600-fold reduction in bending force and a tensile stretch capacity of up to 520%, significantly outperforming brittle parent materials. Out-of-plane compression tests revealed a five-fold increase in energy absorption compared to honeycomb structures, …

Density-Driven Investigations Of Ruthenium Binary Compounds Rux2 (X = O, S, N), Melanie White

UNLV Theses, Dissertations, Professional Papers, and Capstones

Exploration and fine-tuning of the energy landscape of materials can be accessed by means of changes in material density, a key principle of high pressure research. Density-driven changes impact variations in oxidation states and coordination numbers for the element constituents of a compound. Pressure-induced modification of intrinsic density can promote the formation of new materials, variations in physical properties, and transformations in crystallographic symmetry. With this as our foundation, we focus on ruthenium binary compounds - altering the anion species to change electronegativity while probing pressure and temperature effects. This led us to the present study of ruthenium oxide RuO2, …

Development Of Uranium Fluoride Microstructures, Harry Jang

UNLV Theses, Dissertations, Professional Papers, and Capstones

Uranium microstructured materials with controlled size and shape have found applications in several branches of the nuclear industry including as targets for medical isotopes production, fuels for nuclear reactors, standards for analytical measurements, and energy sources for space exploration. Morphological studies of actinide materials are also highly relevant to nuclear forensics-related work. Other potential applications include information storage, catalysis, sensors, and luminescent devices. Most studies on uranium microstructured materials have focused on binary oxides, nitrides, carbides, and fluorides, with the spherical shape being the dominant morphology. Prior to the work reported in this dissertation, aside from UF4 microspheres (ms) and …

Synthesis And In Vitro Testing Of Mg-6zn-Xhap Biocomposites From Beef Bone As Biodegradable Bone Implant Material, Jojor Lamsihar Manalu, Francisca Tjhay, Theodora Kristoforus, Sovian Aritonang

Journal of Mechanical Engineering Science and Technology (JMEST)

This study aimed to develop biodegradable Mg-6Zn hydroxyapatite (Mg-6Zn HAp) biocomposites for potential use in bone replacement applications. The hydroxyapatite (HAp) powders, sourced from cow bone, were synthesized through an eco-friendly and cost-effective process, leveraging bioresources for material sustainability. The Mg-6Zn and HAp powders were mechanically mixed through ball milling for six hours to ensure homogeneity. The resultant powder mixture was then subjected to isostatic pressing at a high pressure of 570 MPa, forming a dense coin-shaped composite with a 1.5 cm diameter. This coin was consolidated in a capsule furnace at elevated temperatures for one hour to enhance material …

Analysis Of Tidal Energy Potential In The Merauke Papua River Waters Indonesia, Peter Sahupala, Daniel Parenden

Journal of Mechanical Engineering Science and Technology (JMEST)

The purpose of this study is as a source of information to study the potential of tidal energy at the estuary of the Maro River in the waters of Merauke Regency. This study uses a quantitative method, while the method for determining the location of the study used is the purposive sampling method where the data collection point is right at the end of the estuary of the Maro River because it faces directly onto the Arafura Sea. Tide data for 5 months, namely September 1, 2023 to January 31, 2024 with a pool area of 1,260,000 m2, with the …

Study On Thermal-Fluid-Solid Coupling Characteristics For Helicopter Intermediate Spiral Bevel Gear Reducer, Dongping Sheng, Jie Yang, Chun Su

Journal of Mechanical Engineering Science and Technology (JMEST)

In the helicopter transmission system, the intermediate reducer is particularly special. It uses bevel gear pairs to change the transmission direction and to transfer the rotational speed effectively. Therefore, an in-depth study of the spiral gear pair is crucial to improve the overall performance of the helicopter rotor system. This study focuses on the study of the thermal-fluid-solid coupling characteristics and one-way steady-state thermal finite element analysis are conducted based on volume of fluid multiphase flow simulation theory to provide strong support for the design and optimization of the helicopter intermediate reducer. Several conclusions could be obtained. Firstly, it could …

Characteristics Of Liquid Products From Spirulina Platensis Pyrolysis Under Microwave Irradiation With Activated Carbon Additive, Mohammad Mirza Yuniar Romaz, Sukarni Sukarni, Retno Wulandari

Journal of Mechanical Engineering Science and Technology (JMEST)

Global energy consumption has surged due to the population's rapid growth, leading to a switch to using renewable and clean energy. Among various strategies for developing renewable and clean energy, biomass pyrolysis emerged as attractive, and microwave irradiation pyrolysis is a prominent technique. This research aims to determine the ideal parameters for microwave-assisted pyrolysis of Spirulina platensis (SP) microalgae in order to produce high-value liquid products with the addition of activated carbon (AC) additives. Liquid bio-oil products were characterized concerning their calorific value, chemical bonds, and thermal stability. This research also investigates product distribution as a function of AC loading. …

Optimization Of The Number Of Cylinder Blades In Coffee Pulper Machine: Finite Element Analysis And Simple Additive Weighting Methods, Mochamad Rifki Syahriza, Dwi Djumhariyanto, Nasrul Ilminnafik, Mahros Darsin, Danang Yudistiro, Hari Arbiantara Basuki, Robertoes Koekoeh Koentjoro Wibowo, Ahmad Syuhri, Sumarji Sumarji

Journal of Mechanical Engineering Science and Technology (JMEST)

The increasing interest in coffee in all circles means that coffee production and quality must always increase due to consumer demands. One way to maintain the quality of coffee beans is by breaking them down using a huller machine. This research aims to improve the optimization of coffee machines by modifying the cylinder blades of huller machines with variations of 3, 4, 5, and 7 cylinder blades in terms of static loading design and quality and production capacity of coffee bean breaking. The experiment was carried out using 400 rpm and breaking 10kg of dry coffee cherries every time the …

Simulation-Based Methodology To Investigate The Impact Of Material Type And Compressive Speed Variation On Effective Strain Rate And Springback, Radhi Nurvian Amrullah, Syamsul Hadi, Muhammad Akhlis Rizza

Journal of Mechanical Engineering Science and Technology (JMEST)

To obtain the desired results in the manufacturing process, especially the bending process, the occurrence of springback must be reduced. The effective strain rate must be increased to predict the increase in material. This study uses a simulation method to determine the influence of material type and compressive speed variation on spring back and effective strain rate. This study uses 3 kinds of materials: JIS SPHD, JIS A1100 BE, and JIS SN400A, and speed variations, namely: 90 mm/s, 105 mm/s, and 120 mm/s. This study shows that JIS SN400A material has the smallest springback value compared to JIS A1100 BE …

Turbine Engine Reliability Analysis Using Reliability Availability Maintainability (Ram), Oyong Novareza, Zefry Darmawan, Nasir Widha Setyanto, Effendi Bin Mohamad

Journal of Mechanical Engineering Science and Technology (JMEST)

Electrical energy is a vital necessity characterized by ever-increasing electricity consumption. The most dominating power plant in Indonesia in supplying electricity is the steam power plant, which is 50%. In its implementation, there is damage that occurs where the highest damage is to the general unit with the highest damage to the turbine unit. Therefore, the author uses the reliability, availability, and maintainability method or RAM. The purpose of this study is to determine the value of RAM on the turbine system at PLN and provide recommendations for improvements to system performance. The results showed that the MTTF and MTTR …

Innovative Approaches For Improving Orc Performance: A Review Of Pure Fluids, Zeotropic Mixtures, And Nanoparticles, Ebenezer Kumi, Vasudevarao Veeredhi, Christopher Enweremad

Journal of Mechanical Engineering Science and Technology (JMEST)

Although the organic Rankine Cycle (ORC) is said to effectively capture low-grade heat, its commercialization has been limited because of working fluid constraints and inefficiencies resulting from operating at low temperatures. This study reviews the working fluids used in organic Rankine cycles and examines how nanoparticles could enhance the efficiency of the ORC, by enhancing the thermophysical properties of the working fluids. Results from this review showed that zeotropic mixtures of pure fluids, provide a viable approach to improving the thermophysical characteristics of organic working fluids and have the potential to achieve thermo-economic performance superior to that of individual pure …

Innovations In Additive Manufacturing For Socket Fabrication: An Overview, Linda Ziyadatul Faiza, Wahyu Caesarendra, Wahyu Dwi Lestari

Journal of Mechanical Engineering Science and Technology (JMEST)

Additive Manufacturing (AM) has transformed the prosthetics industry, particularly in socket production, which plays a critical role in the comfort, fit, and functionality of prosthetic limbs. This article examines the latest advancements in AM technologies and their applications in socket fabrication. Key techniques like stereolithography (SLA), selective laser sintering (SLS), and fused deposition modeling (FDM) have facilitated the production of highly personalized, lightweight, and durable prosthetic sockets. These methods not only improve design precision but also allow for the use of biocompatible, flexible materials, enhancing both comfort and functionality. Digital design tools have streamlined the production process, reducing lead times …

Structural Simulation Of Wheelchair Ramp Using Finite Element Method, Bhre Wangsa Lenggana, Agung Nugroho, Ubaidillah Ubaidillah

Journal of Mechanical Engineering Science and Technology (JMEST)

Wheelchairs are essential mobility aids for people with disabilities, but they are often limited to flat surfaces and cannot overcome height differences. Portable ramps are an effective solution to overcome this limitation. This research aims to simulate and analyze the structure of a portable ramp for wheelchairs. Simulations were conducted using finite element method analysis software to assess the portable ramp's von Mises stress, deformation, and safety factor in various loading positions. Finite element method (FEM) analysis software was utilized to evaluate key mechanical properties, including von Mises stress, deformation, and safety factor, under different loading conditions and positions. The …

Analysis Of Biomass Briquette Mixed Bagasse And Sugarcane Peel On The Performance Of Forced Top-Lit Updraft Gasifier Stove, Intan Hardiatama, Aron Enruico, Yuni Hermawan, Muhammad Trifiananto, Skriptyan N.H. Syuhri

Journal of Mechanical Engineering Science and Technology (JMEST)

The population growth in Indonesia from 270 million in 2020 to 279 million in 2024 has increased LPG consumption, potentially leading to future fuel shortages. The top-lit updraft (TLUD) gasifier stove using renewable biomass materials, offers a sustainable alternative. Biomass such as bagasse and sugarcane peel can be optimized into charcoal briquettes with high calorific value and low emissions. The calorific value of briquettes can be further enhanced by blending other high–calorific biomass materials. This experimental research focuses on testing the calorific value of raw bagasse and sugarcane peel before carbonization, as well as briquette mixtures (70:30, 50:50, 30:70) using …

Characterization And Performance Nanofiltration Membranes In Water Quality For Goldfish (Carassius Auratus) Aquaculture, Inpita Casuarina Eqisetia Utari, Uun Yanuhar, Asus Maizar Suryanto Hertika, Heru Suryanto, Jibril Maulana, Nico Rahman Caesar, Mahrus Ismail, Leong-Seng Lim

Journal of Mechanical Engineering Science and Technology (JMEST)

Water quality is an important factor in aquaculture activities, including goldfish (Carassius auratus) farming. One approach to improving water quality is the use of nanofilters. This study aims to evaluate the performance of nanofilters made from Sargassum sp. with the addition of copper oxide nanoparticles. The method used involves the fermentation of bacterial cellulose from Acetobacter xylinum using Sargassum sp. extract as a medium, followed by homogenization and the addition of CuO-NPs at concentrations of 0.5%, 1%, and 1.5%, and subsequent oven drying. The nanofilter membrane will then be analyzed using SEM, XRD, and FTIR to characterize its properties. Performance …

The Potential Of Ramie Fiber As Reinforcement In Calcium Carbonate-Filled Polyester Resin Matrix Composites For Roofing Applications, Reinaldo Reinaldo, Djoko Setyanto

Journal of Mechanical Engineering Science and Technology (JMEST)

Polymer matrix composite roofing materials available in the Indonesian market typically consist of 30%wt chopped strand mat glass fiber embedded in unsaturated polyester resin, filled with 30 parts per hundred resin (PHR) calcium carbonate. The aim of this research is to evaluate whether natural ramie fibers can potentially replace glass fibers. In the first stage of the study, we compared three types of natural fibers abundant in Indonesia: banana stem fibers, sugarcane bagasse, and ramie. Showed that ramie fiber performed the best. Its flexural strength, flexural modulus, and impact toughness were the highest, measured at 191.57 MPa, 6691 MPa, and …

Captivating Combustion Traits Of Bio-Oil Droplets Enriched With Bio-Additives From The Areca Shell Waste, Muhammad Alif Raehan, Helen Riupassa, Hendry Y. Nanlohy

Journal of Mechanical Engineering Science and Technology (JMEST)

Fuel derived from crude vegetable oil, such as coconut oil, holds promise as an alternative energy source to mitigate the increasing reliance on fossil fuels driven by population growth and industrial activities. The experiment involved suspending a single droplet of crude coconut oil mixed with activated carbon from areca shell waste and placed at the junction on R-type thermocouple (Pt/Pt-Rh13%). The droplets were ignited using a hot wire and subjected to atmospheric pressure and room temperature. Coconut oil comprises a saturated triglyceride carbon chain compound of approximately 91%, and areca shell waste possesses a porous structure that fosters favorable interactions …

Characterization Of Hydroxyapatite Derived From Scallop Shell Waste Synthesized By Sonochemical Method With Different Temperature Calcination, Diki Dwi Pramono, Poppy Puspitasari, Aminnudin Aminnudin, Jeefferie Abd Razak

Journal of Mechanical Engineering Science and Technology (JMEST)

One common bio-ceramic material used in the biomedical industry is hydroxyapatite. Because of its crystallographic and molecular resemblance to the hard tissues of the human body, hydroxyapatite is thought to form. Scallop shells are one natural source of hydroxyapatite, which is high in calcium. This study examines how the calcination temperature affects the characteristics of hydroxyapatite made from leftover scallop shell. Hydroxyapatite was synthesized via the sonochemical method, with calcination conducted at temperatures of 900°C, 1000°C, and 1100°C. The hydroxyapatite that was prepared was assessed using Xray diffraction (XRD) to determine the phase and crystallite size, Scanning Electron Microscopy (SEM) …