Engineering Commons^™

Breaking Through The Strength-Ductility Trade-Off Of Lpbf-Produced Ti-Xnb Alloys From Mixed Powders Via Ω-Phase Induced Heterostructure, Jian Bo Jin, Shengfeng Zhou, Huan Yang, Junjie Yang, Zhiguo Zhang, Baisong Guo, Lai Chang Zhang

Research outputs 2022 to 2026

Highlights Powder-mixed Ti-35Nb alloy produced by LPBF breaks through the strength-ductility trade-off. The ultimate strength, uniform elongation and Young’s modulus of heterostructured Ti-35Nb alloy are (806 ± 7) MPa, (18.0 ± 1.1)%, and (68 ± 6) GPa, respectively. In-situ laser re-melting improves elemental distribution uniformity in LPBF-produced powder-mixed Ti-xNb alloys. Optimized Nb content induces the phase transformation of β + α′ → β + ω in Ti-xNb alloy. Heterostructured β + ω/β enhances the strength-ductility synergy of Ti-35Nb alloy.

Analysis Of Progressive Failure From Hydrofracturing Tests In Boise Sandstone, Alejandra Sanchez Arizmendi

Boise State University Theses and Dissertations

Sealed borehole laboratory hydrofracturing tests with acoustic emission monitoring were used to investigate the acoustic emission activity, damage thresholds, progressive failure, and tensile strength as a function of injection rate for twenty Boise Sandstone specimens. Four injection rates 15.7, 31.4, 62.8, and 125.6 mL/minute were used in the testing.

Increasing the injection rate initially increased and then decreased acoustic emission activity. The highest injection rate resulted in the lowest number of AE hits. The acoustic emission data was collected via two ultrasonic sensors. The highest average AE hits at the 31.4 mL/min injection rate was 613 and the lowest average …

The Effect Of Loading Conditions And Specimen Size On The Tensile Strength Of Ring-Shaped Specimens, Kolby Scott Mcclure

Boise State University Theses and Dissertations

This study introduces a custom-built direct tension testing apparatus designed for ring-shaped rock specimens. The apparatus applies a uniform axial load to the inner surface of the ring and is compatible with standard geotechnical testing equipment. Using this device, 176 granite specimens sourced from Horseshoe Bend, Idaho, were tested under three configurations: Brazilian, indirect ring tension, and direct ring tension. Only specimens exhibiting valid diametrical splitting failure modes (126 out of 176) were included in the final analysis. Direct tension tests yielded the lowest tensile strengths, followed by Brazilian tests, with indirect tension tests producing the highest values. While scatter …

Stimulation And Recording Interfaces For Data Transmission To And From A Micro Neural Stimulation Device, Morgan Riley

Boise State University Theses and Dissertations

Advancements in neuromodulation for treating neurological disorders increasingly rely on selective peripheral nerve stimulation rather than whole-nerve activation. Traditional approaches engage all fascicles, causing off-target effects such as involuntary muscle contractions and pain. To address these challenges, this research proposes a minimally invasive microdevice that integrates wireless galvanic impulse communication with an epineural multi-contact nerve cuff. This design facilitates high-throughput, low-power stimulation, recording, and data transfer. Development efforts include optimizing neural stimulation protocols, validating deep tissue galvanic transmission, and fabricating a multi-channel nerve cuff for stable electrode–tissue interfacing. In parallel, custom depth-controlled intramuscular arrays enable high-density electromyography (EMG) recording during …

Harnessing Bioscaffold-Coupled Stimulation Through Electroactive Graphene Foam For Enhanced Cellular And Mechanical Responses: Applications In Cartilage Tissue Engineering, Mone't Sawyer

Boise State University Theses and Dissertations

Osteoarthritis is a leading cause of joint degeneration, with limited treatment options that fail to restore native cartilage. Tissue engineering offers a promising strategy by combining cells, scaffolds, and bioactive cues to regenerate functional tissue, though challenges remain in developing systems that integrate and precisely control these signals in three-dimensional environments. This work establishes a scaffold-coupled electrical stimulation (ES) platform using electroactive graphene foam (GF) to modulate cellular and mechanical responses relevant to cartilage tissue engineering. Custom stereolithography-printed bioreactors were developed to deliver low-voltage biphasic square waves (20–60 mVpp, 1 kHz) directly to GF scaffolds under submerged culture, maintaining waveform …

Harnessing The Mechanical And Gelation Behavior Of Tyramine-Substituted Silk Fibroin Bioinks Through Integration Into A Modular And Low-Cost 3d Bioprinting Platform, Sourjjadeepta Biswas

Boise State University Theses and Dissertations

3D printing has become an indispensable tool in research labs across the globe. Yet, when it comes to bioprinting with custom or sensitive bioinks, accessible options remain limited. Commercial systems are often prohibitively expensive and restricted to proprietary materials, while DIY setups frequently lack the precision and compatibility needed for biologically relevant printing. Moreover, tunable bioinks that align with real-world biological constraints are still hard to come by. To address these gaps, we developed a modular, low-cost bioprinting platform tailored for tyramine-substituted silk fibroin (TA-SF) hydrogels-biocompatible materials known for their rapid gelation, tunable stiffness, and potential to support cell differentiation …

Design Of A Novel Robust Adaptive Fractional-Order Model Predictive Controller For Boost Converter Using Grey Wolf Optimization Algorithm, Chao Peng, Seyyed Morteza [email protected] Ghamari, Hasan Mollaee, Omid Rezaei

Research outputs 2022 to 2026

Boost converters play a crucial role in power electronics but present control challenges due to their non-minimum phase behavior and nonlinear dynamics at high switching frequencies. To address these issues, this work proposes a Fractional-order adaptive Model Predictive Control (FO-MPC) framework incorporating Exponential Regressive Least Squares (ERLS) for system identification. Traditional MPC frameworks often rely on accurate mathematical models, which are difficult to obtain in real-world scenarios. This adaptive modelling approach based on ERLS identification method eliminates the need for precise system models, improving robustness and adaptability under parameter variations. Additionally, a FO derivative term enhances damping, stability, and noise …

Machine Learning Assisted Quality Control In Metal Additive Manufacturing: A Review, Zeqi Hu, Changlin Huang, Lechun Xie, Lin Hua, Yujie Yuan, Lai Chang Zhang

Research outputs 2022 to 2026

Additive manufacturing (AM) promotes the production of metallic parts with significant design flexibility, yet its use in critical applications is hindered by challenges in ensuring consistent quality and performance. Process variability often leads to defects, insufficient geometric accuracy and inadequate material properties, which are difficult to effectively manage due to limitations of traditional quality control methods in modeling high-dimensional nonlinear relationships and enabling adaptive control. Machine learning (ML) offers a transformative approach to model intricate process-structure-property relationships by leveraging the rich data environment of AM. The study presents a comprehensive examination of ML-driven quality assurance implementations in metallic AM. First, …

Biopolymer-Based Membranes And Their Application In Per- And Polyfluorinated Substances Removal: Perspective Review, Roham Ghanbari, Ratish Permala, Stefan Iglauer, Masoumeh Zargar

Research outputs 2022 to 2026

Over the past 2 decades, per- and polyfluoroalkyl substances (PFAS) have attracted considerable attention due to their widespread occurrence and adverse effects on both the environment and human health. PFAS possess strong carbon‑fluorine bonds that confer exceptional chemical stability and resistance to natural degradation; their fluorinated chains are highly hydrophobic and oleophobic, while their polar functional groups contribute to amphiphilic behavior and water solubility. Certain PFAS thus pose serious risks to living organisms, especially mammals. Membrane filtration is recognized as a particularly effective technique, achieving removal efficiencies greater than 99 % for long-chain-PFAS (including anionic, cationic, and zwitterionic PFAS molecules). …

Interface Engineering And Safety In Solid-State Batteries: Advancing From Human-Centered Insights To Ai-Driven Innovations, Elnaz Karimi, Stefan Iglauer, Muhammad Rizwan Azhar

Research outputs 2022 to 2026

Solid-state batteries (SSBs) represent a transformative advancement in energy storage, offering superior safety, higher energy density and extended cycle life compared to conventional lithium-ion batteries (LIBs). However, challenges related to interface engineering—particularly in ensuring stable electrochemical performance and preventing lithium dendrite formation—have hindered their widespread adoption and can compromise safety. Effective interface engineering is critical for mitigating interfacial resistance, enhancing mechanical stability and preventing thermal runaway, all of which are vital for improving battery reliability. The integration of artificial intelligence (AI) and machine learning (ML) in this context accelerates battery optimization by enabling predictive modelling of interfacial behaviour, material discovery …

Next-Generation Underwater Localization: Artificial Intelligence-Based And Energy-Aware Approaches, Mainul Islam Chowdhury, Quoc Viet Phung, Iftekhar Ahmed, Walid K. Hasan, Daryoush Habibi

Research outputs 2022 to 2026

Designing accurate, reliable, and energy-efficient localization techniques for underwater acoustic networks is highly challenging due to factors such as large propagation delays, the absence of Global Positioning System (GPS), node mobility, and limited acoustic link capacity. In any underwater sensor network (UWSN) monitoring application, data collected by underwater nodes becomes more meaningful when accompanied by location information. However, traditional localization methods often rely on geometric models and statistical filters that are highly sensitive to sensor noise and communication constraints. Energy consumption is another primary concern in UWSNs, not only because replacing and recharging underwater batteries are challenging, but also due …

Application Of Plastic Waste As A Sustainable Bitumen Mixture—A Review, Nuha S. Mashaan, Thakur Chamlagai

Research outputs 2022 to 2026

Plastic waste is growing rapidly, while asphalt binders remain heavily reliant on petroleum bitumen. Incorporating recycled plastics into bitumen can divert waste and enhance pavement performance. This review compiles 251 experimental records from 56 studies to evaluate how plastic type, dosage, and processing conditions affect softening point, penetration, and viscosity. Across studies, plastics (PET, LDPE/HDPE/LLDPE, PP, and hybrids) consistently stiffen binders, reducing penetration and increasing softening point and viscosity, thereby improving rutting resistance while potentially raising mixing/compaction demands. Using grouped cross-validated machine-learning models (median baseline, ridge, random forest, XGBoost), we quantify the predictability of binder properties and show that nonlinear …

Theory And Technology Of Enhanced Coal Seam Gas Production By Integrated Drilling, Punching And Fracturing In Coal Mine: Part 1 Theory, Shiyao Yu, Xianbo Su, Jinxing Song, Qian Wang, Zhenjiang You

Research outputs 2022 to 2026

Coal seams in China are typically characterized by high coal seam gas content and low permeability, posing challenges for efficient coal seam gas extraction. However, achieving successful boreholes, especially in soft coal formations, remains a challenge. The mechanisms underlying permeability improvement in different coal structures need further exploration. Therefore, this paper is focused on the fundamental principles of permeability improvement in soft coal through hydraulic punching, and in hard coal via hydraulic jet fracturing. Firstly, borehole instability results from a dynamic interplay of four factors: in situ stress, coal structure, mechanical properties of coal with fluid, and drilling technology. While …

Feasibility And Potential Of Electric Air Taxis For Long Distance Airport Access/Egress Trips, Atul Subedi

All Graduate Theses and Dissertations, Fall 2023 to Present

Getting to the airport is often one of the most stressful parts of a trip, especially for people who live far from the airport. In the United States, many travelers live more than an hour’s drive from a major airport, and their choices such as driving, using public transit, or paying for ride-hailing can be time-consuming, expensive, and inconvenient. A new technology, Electric Air Taxis (EATs), is being developed as a potential solution. These small, battery-powered aircraft could offer faster, cleaner, and more direct connections to airports. However, the success of EATs depends not only on the technology itself but …

Utilizing Diatoms In Wastewater Treatment For Pollutant Removal, Ceaira D. Howard

All Graduate Theses and Dissertations, Fall 2023 to Present

Wastewater treatment systems are increasingly challenged by a complex mix of pollutants including excess nutrients, organic dyes, and persistent chemicals like per- and polyfluoroalkyl substances (PFAS). Conventional treatment technologies often struggle to effectively and affordably remove these contaminants. This study explores the use of two diatom species, Phaeodactylum tricornutum and Navicula cryptocephala var. veneta, both single-celled microalgae with silica-based cell walls, as an environmentally sustainable approach to tertiary wastewater treatment. Diatoms offer dual functionality through surface adsorption properties and metabolic flexibilities, making them promising candidates for integrated treatment strategies.

To test the trophic flexibilities of diatoms, P. tricornutum was …

Quicklime-Based Self-Healing Concrete For Bridge Deck Applications, Mehrnoosh Nazari

All Graduate Theses and Dissertations, Fall 2023 to Present

Concrete is one of the most widely used construction materials in the world. However, over time, it can crack and deteriorate, especially on roads and bridges exposed to harsh weather and deicing salts. Inspired by the long-lasting durability of ancient Roman concrete, this study explores the self-healing capabilities of concrete incorporating quicklime (calcium oxide) aggregates to extend the service life of bridge decks. For this purpose, three concrete mixtures were developed using local materials: one without quicklime (C-Q 0%) and two with 2% (C-Q 2%) and 4% quicklime (C-Q 4%). These mixtures were tested for fresh properties, strength, durability, and …

Jhtdb-Wind: A Web-Accessible Large-Eddy Simulation Database Of A Wind Farm With Virtual Sensor Querying, Xiaowei Zhu, Shuolin Xiao, Ghanesh Narasimhan, Luia A. Martinez-Tossas, Michael Schnaubelt, Gerard Lemson, Hanxun Yao, Alexander S. Szalay, Dennice F. Gayme, Charles Meneveau

Mechanical and Materials Engineering Faculty Publications and Presentations

This paper introduces JHTDB-wind (https://turbulence.idies.jhu.edu/datasets/windfarms), a publicly accessible database containing large-eddy simulation (LES) data from wind farms. Building on the framework of the Johns Hopkins Turbulence Database (JHTDB), which hosts direct numerical and some large-eddy simulation datasets of canonical turbulent flows, JHTDB-wind stores the full space-time (4D) history of the flow and provides users the ability to access and query the data via a web-based virtual sensor interface. The initial dataset comprises LES results from a large wind farm with 6 X 10 turbines, modeled using a filtered actuator line method, under conventionally neutral atmospheric conditions. This data comprises one …

Investigation Of Insertion Loss In Inkjet-Printed Coplanar Waveguide Based On Drying Temperature, Jun Ho Yu, Sung Min Sim, Jin Woo Choi, Sang Ho Lee, Jung Mu Kim

Michigan Tech Publications

In this study, we propose an optimized inkjet printing process to improve the insertion loss of inkjet-printed coplanar waveguide (CPW) transmission lines. The process involves varying the drying temperature and adjusting the number of printing steps to investigate their effects on the electrical characteristics of the printed CPW. The relationships between surface roughness, surface cavities, morphological changes, and insertion loss are studied by conducting atomic force microscopy analysis and by examining the insertion loss up to 3 GHz. The printed CPW that underwent low-temperature drying after the first printing and high-temperature drying after the second printing before sintering showed improved …

Full Factorial Design Of Carbon Content And Heating Temperature On Height Reduction In Bonnell Springs, Yurida Ekawati, Cendana Anggun Sasmitha, Mochamad Syamsul Ma’Arif

Journal of Mechanical Engineering Science and Technology (JMEST)

The durability of Bonnell springs, which are widely used in the manufacture of spring beds, is often compromised by height reduction during use, which negatively impacts product comfort and quality. This study aims to minimize spring height reduction by investigating the effects of heating temperature and carbon content in the spring steel. A full factorial experimental design was applied using two factors: heating temperature (250°C, 260°C, and 270°C) and carbon content (0.72%, 0.73%, and 0.74%). Nine treatment combinations were tested, with five replicates each, and the height reduction values were measured after 100 compression cycles. The data were analyzed using …

Simulation Of Stress, Deformation, And Vibration In Unlubricated Ball Bearings At Varying Rotational Speeds, Billy Dwiki, Moh. Hartono

Journal of Mechanical Engineering Science and Technology (JMEST)

Bearings are critical components in rotating machinery, and their performance is highly influenced by operational factors such as rotational speed, load, and lubrication. This study aims to analyze the deformation, stress, and dynamic behavior of SAE 52100 bearings under dry operating conditions at various rotational speeds, as well as to propose mitigation strategies for high-speed industrial applications. A finite element simulation was conducted using ANSYS R19.2 to evaluate the total deformation, equivalent elastic strain, Von Mises stress, and vibrational characteristics of a 6204-type SAE 52100 bearing. The simulations were performed across a speed range of 600 to 2000 RPM under …

Optimizing Zeolite Catalysts For Efficient Ldpe Plastic Waste Pyrolysis, Hilda Porawati, Mazwan Mazwan, Sukadi Sukadi

Journal of Mechanical Engineering Science and Technology (JMEST)

The problem of plastic waste, particularly from low-density polyethylene (LDPE) plastic bags, poses a significant challenge in environmental management due to its non-biodegradable nature and widespread use in daily life. This study evaluates the influence of catalyst types on the characteristics and energy efficiency of liquid fuel products produced from LDPE waste pyrolysis. The three treatments compared were no catalysts, natural zeolite catalyst, and synthetic zeolite catalysts, each subjected to three different temperature variations: 250°C, 300°C, and 350°C. The observed parameters in this study were volume, product mass, cetane index, density, sulfur content, viscosity, flash point, calorific value, and energy …

Thermophysical, Rheological And Wear Resistance Of Canola Oil Biolubricant With Calcium Carbonate Additive Nanoparticle As Coolant In Cnc Machining, Alfandi Jaelani, Poppy Puspitasari, Diki Dwi Pramono, Alief Muhammad, Muhammad Kozin, Muhammad Kashif

Journal of Mechanical Engineering Science and Technology (JMEST)

Vegetable oil-based cutting fluids are of great importance in supporting green and sustainable manufacturing. This research introduces a new groundbreaking vegetable lubricant formulated with canola oil as the base material, coupled with CaCO3 nanoparticles synthesized from scallop shell waste and used as a cutting fluid in the AISI 1045 CNC machining process steel sprayed with minimum quantity lubrication (MQL). This investigation delves into the thermophysical, rheological, and wear resistance of the developed bio-lubricant. The results of this analysis show density value increased in the canola + CaCO3 0.15% sample by 3.28% of the pure canola sample, as did the viscosity …

Improvement Of Thermal Energy Storage Performance In Al-Al2o3 Composites Through Additions Of Copper: Evaluation Of Microstructure And Thermal Properties, Muhammad Hasan Basri, Ramang Magga, Muhammad Syaiful Fadly, Zikri Arifansyah Djaba, Muhammad Iqbal Ibrahim, Hidayat Hidayat, Yandi Yandi

Journal of Mechanical Engineering Science and Technology (JMEST)

The study aims to evaluate the influence of adding copper aluminum–alumina composite (Al–Al₂O₃) against characteristic thermal properties through metallurgical powder. Three variations of the composition of weight copper were used, namely 5%, 10%, and 15%, with aluminum as the matrix and alumina as the reinforcement. Thermal test covering analysis of thermal conductivity, specific heat, and microstructure characterization using SEM-EDX. The results show that adding Cu increases thermal conductivity significantly, with the highest mark achieved in the 15% Cu composite (6.47 W/m.°C). However, the increase in Cu content above 10% causes the agglomeration of particles and enhancements in porosity, which harms …

Numerical Investigation Of Ethanol-Enriched Diesel And Biodiesel Fuels In A Diesel Engine, Annisa Bhikuning, Hezron Elyakim Potto, Sandi Apriandi Setiawan, Jamal F. Jati

Journal of Mechanical Engineering Science and Technology (JMEST)

This study explores the effects of ethanol blending on the performance and emissions of a compression ignition (CI) engine using both diesel and biodiesel as base fuels. Motivated by increasing environmental concerns regarding pollutant emissions from conventional diesel engines, ethanol was introduced as an oxygenated additive to improve combustion characteristics and reduce the formation of harmful exhaust emissions. Ethanol’s high oxygen content promotes more complete combustion, potentially lowering carbon-based emissions such as carbon monoxide (CO), particulate matter (PM), and unburned hydrocarbons. In this study, performance and emission parameters were simulated using Diesel-RK software at various engine speeds of 1500, 2000, …

One-Way Thermal-Fluid-Solid Coupling Analysis Of Helicopter Tail Reducer With Spiral Bevel Gear, Dongping Sheng, Zhongyuan Ma, Chenqi Zhou, Haidong Feng, Hun Guo, Chun Su

Journal of Mechanical Engineering Science and Technology (JMEST)

This research focuses on investigating the thermal-fluid-solid coupling behavior within spiral bevel gears to enhance the bearing capacity and extend the operational service life of the gear reducer located in the helicopter tail gearbox. The study commences by constructing detailed, parametrically defined threedimensional digital models. These models accurately represent the critical components: the spiral bevel gear itself, the surrounding gearbox housing, and the supporting gear shaft, based directly on the specifications of an actual helicopter tail reducer assembly. Subsequently, the analysis proceeds with a one-way, steadystate thermal-solid coupling simulation performed on the established model assembly. This critical simulation phase aims …

The Impact Of Pine Resin-Epoxy Ratios On Fire Resistance And Acoustic Performance Of Banana Fiber Composites, Cokorda Istri Putri Kusuma Kencanawati, Dewa Ngakan Ketut Putra Negara, I Gede Andy Andika Parahita

Journal of Mechanical Engineering Science and Technology (JMEST)

Because of their low environmental impact and biodegradability, composite materials derived from natural fibers and resins have drawn interest as sustainable substitutes for synthetic materials in thermal and acoustic applications. Two promising natural components are banana stem fiber and pine resin, but they need to be modified due to their mechanical limitations and flammability. Epoxy resin is commonly used to enhance structural performance; however, its effects on acoustic and fire resistance properties require further investigation. This study examined how different epoxy resin contents affected the sound absorption and fire resistance of composites made from banana stem fiber and pine resin. …

Effect Of Argon Gas Flow Rate On Crystal Structure, Morphology, And Optical Properties Of Cigs Film For Photodetector Applications, Nurul Lathi’I Fatul Chamidah, Fadilah Wulan Cahyani, I Gusti Ayu Isnaini Fatha Ramadhani, Erma Surya Yuliana, Nasikhudin Nasikhudin, Safwan Abd. Aziz, Nandang Mufti

Journal of Mechanical Engineering Science and Technology (JMEST)

CIGS material can be used as a material for photodetector applications. The deposition of CIGS thin films remains challenging. Generally, argon is used as a gas to bombard the CIGS material through the sputtering method. This study fabricated photodetectors by varying the argon gas flow rate (50-80 sccm) to investigate its effect on device performance. XRD, SEM, UV-Vis, and photoresponse tests were characterized. Structural analysis using XRD showed a weak (112) diffraction peak, indicating that the resulting film was not fully crystalline, but rather consisted of a nanocrystalline phase, even partly amorphous, with small crystallite sizes. According to the SEM …

Spray Angle On The Performance Of Split-Type Ac Condenser Installed On Concrete Rooftop In Tropical Climate, Kennedy Kennedy, I N Frenki Aryana, Basri Basri

Journal of Mechanical Engineering Science and Technology (JMEST)

This study investigated the influence of different water spray angles (0°, 15°, and 30°) on the thermal and energy performance of a split-type air-conditioning (AC) condenser installed on a concrete rooftop in a tropical climate. An experimental setup was designed to replicate actual concrete rooftop conditions, focusing on the condenser inlet temperature, compressor power consumption, and system coefficient of performance (COP). A 6-minute ON and 6-minute OFF intermittent spray cycle was employed to optimise water usage and minimise excessive humidity. Experimental measurements were conducted on a 9,000 Btu/h split-type unit equipped with a nozzle system connected to a 200 L …

The Effect Of Preheater On Heat And Mass Transfer Efficiency Using Rotating Drum Roaster, Melisa Surya Andini, Retno Wulandari, Heru Suryanto

Journal of Mechanical Engineering Science and Technology (JMEST)

Indonesia is the third-largest coffee producer globally, facing challenges including rising raw material costs, increased energy consumption, and unpredictable weather conditions. One potential solution is optimizing energy efficiency during roasting. This study investigates the effect of preheating on time and energy efficiency in heat and mass transfer by utilizing waste heat to preheat green Robusta coffee beans. The experiment was conducted on a laboratory scale using a rotating drum roaster with a double-layer drum made of stainless steel and clay, at 200 °C under atmospheric pressure. Two treatments were applied: roasting with a preheater and without, each repeated three times …

Impact Of Cpo And B35 On Diesel Engine Rocker Arm Wear During Long-Term Operation, Fawwaz Aqilah Nurmansyah, Nur Fadilah Rizky Supramono, Muhammad Ikhsan, Erwan Adi Saputro, Wiliandi Saputro

Journal of Mechanical Engineering Science and Technology (JMEST)

The increasing number of motor vehicles has led to higher fossil fuel consumption, contributing to greenhouse gas emissions, climate change, and environmental degradation. As a renewable alternative, biodiesel offers a way to reduce these impacts. Indonesia, with its abundant natural resources, has significant potential for biodiesel production. Crude palm oil (CPO) is a promising feedstock due to its availability and relatively low environmental impact. However, the high costs associated with the transesterification process make direct use of pre-heated CPO an area worth exploring. This study investigates the impact of pre-heated pure CPO compared to B35 ("Dexlite") on rocker arm wear …