Engineering Science and Materials Commons^™

Electropulse Annealing: Phase Composition Of Tial6v4, Vaughn Eckhardt, Ethan Croke, Ian Baker, Russ Taylor

Wetterhahn Science Symposium Posters

Titanium alloy TiAl6V4 is the most ubiquitous titanium alloy used for dental care, aerospace manufacturing, and for high performance vehicles. The material typically undergoes a thermal heat  treatment, but electropulse annealing is another process that involves sending current through the material to heat it up at a quicker rate. The rate of post-annealing cooling is high, and around the material's critical point, its two components, alpha and beta phase, change in relative concentration. After testing multiple current densities and temperatures, in general, as the current density that the sample received during electropulse annealing decreased, both the alpha and beta phases …

Optimization And Energy Efficiency Analysis Of An Automatic Feed Mixer With A Rotating Drum Mechanism, Kris Witono, Talifatim Machfuroh, Nurlia Pramita Sari, Lisa Agustriyana, Aini Lostari

Journal of Mechanical Engineering Science and Technology (JMEST)

Energy-efficient feed mixer machines are important for improving the productivity and sustainability of small and medium-scale livestock farms. Previous studies primarily focused on either structural performance or mixing efficiency, with limited studies integrating both aspects. Therefore, this study evaluated an automatic rotating-drum feed mixer by combining Finite Element Method (FEM) analysis and energy modeling. The study used FEM simulations for different materials, namely A36 steel alloy, stainless steel 304, aluminium 6061, and galvanized steel, with thicknesses of 3 mm and 4 mm, as well as different drum systems. The FEM results showed that all evaluated materials met the minimum safety …

Influence Of Gas Atmosphere And Deposition Time On Si/Mno₂ Thin Films Properties Deposited By Magnetron Sputtering For Supercapacitor Application, Tansya Trisnatika Dewi, Boon Tong Goh, Reza Akbar Pahlevi, Ishmah Luthfiyah, Markus Diantoro

Journal of Mechanical Engineering Science and Technology (JMEST)

Thin films of MnO₂ were successfully deposited onto Si substrates using the magnetron sputtering technique in various gas atmospheres and deposition times to study their influence on the structural, morphological, electrical, and electrochemical properties for application as supercapacitor electrodes. Structural analysis using XRD showed that deposition under an Ar+O₂ gas atmosphere increased the crystallite size and crystallinity of the Si/MnO₂ films, while shorter deposition times reduced the crystallite size and lowered the crystallinity. Surface morphology observation using SEM showed that the film deposited in an Ar+O₂ gas atmosphere had smaller, more uniform, evenly distributed, and closely …

Influence Of Fiber Loading And Cu/Sio₂ Fillers On Mechanical And Physical Properties Of Sugarcane Bagasse Epoxy Composites, Ansor Salim Siregar, Indra Indra, Agung Fauzi Hanafi, Sunny Ineza Putri

Journal of Mechanical Engineering Science and Technology (JMEST)

The rising worldwide need for lightweight, high-strength, and eco-friendly materials has driven considerable investigation into natural fiber composites. This research offers an extensive examination of the creation and characterization of a new hybrid composite designed for high-performance sports equipment. The composite structure consists of an epoxy matrix strengthened with sugarcane bagasse fibers and synergistic blend of copper and silicon dioxide hybrid particulate fillers. Three unique composite variations were created, with systematically adjusted weight fractions of sugarcane bagasse fiber (35%, 31%, 27%) and hybrid fillers. A thorough assessment of mechanical and physical properties was carried out following ASTM standards. The results …

An Analytical Framework For Quantifying Urban And Community Resilience To Natural Hazards From Cell-Phone Gps-Location And Traffic-Flow Data, Georgios Chatzikyriakidis

Civil and Environmental Engineering Theses and Dissertations

Urban areas are increasingly exposed to natural hazards while accommodating a growing share of the global population, yet a consistent science-based framework for quantifying urban and community resilience remains lacking. This dissertation develops a physics-based analytical framework grounded in statistical mechanics and the quantitative theory of Brownian motion. A city is conceptualized as a complex medium in which citizens move analogously to Brownian particles within a viscoelastic environment, influenced by socioeconomic interactions and infrastructure functionality.

A central premise is that urban resilience, interpreted as engineering resilience (an outcome), can be quantified through a single metric: the mean-square displacement MSD=⟨r²(t)⟩, of …

Sorption And Thermal Conductivity Of Concrete Containing Aggregates Of E-Waste, Rakesh Kumar Saini, Praveen Kumar

Journal of Sustainable Construction Materials and Technologies

In many parts of the world, substantial energy is used to maintain comfortable temperatures in inner parts of the buildings for living and working. Construction materials with low thermal conductivity, if used in the exterior walls and façade etc. in such structures can be useful in lowering the energy demand. On the other hand, moisture ingress through sorption is a common factor contributing in degradation of concrete structures with time. Constituents of concrete may be engineered to some extent to get both the desired attributes, lower thermal conductivity and sorption than normal concrete. The rapid increase in electronic waste, or …

Thermal Transient Analysis Of Mahogany Wood Biomass Pyrolysis: The Role Of Zeolite Catalyst Variations On Temperature Distribution, Yusri Yusri, Widya Wijayanti, Mega Nur Sasongko

Journal of Mechanical Engineering Science and Technology (JMEST)

Biomass pyrolysis is a thermochemical process that converts waste into fuel. The use of zeolite catalysts can enhance efficiency by accelerating biomass decomposition. To demonstrate its effect, thermal simulations were conducted using ANSYS Thermal Transient to analyze temperature distribution, reaction rates, and catalyst effectiveness in the pyrolysis process. This study aims to improve thermal efficiency and temperature uniformity by analyzing the effect of 10% and 20% zeolite mixtures on heat distribution and heating rates at input temperatures of 650 K, 750 K, and 850 K, using the 2D axial symmetry method. The simulation was performed under specific boundary conditions: input …

Effects Of Prescribed Burning On Forest Soil Low-Molecular-Weight Organic Acids, Ariana Rivera-Anazco

Honors Theses

Low-molecular-weight organic acids (LMWOAs) play important roles in nutrient mobilization, microbial activity, and carbon cycling in forest soils, yet their response to prescribed fire and thinning remains poorly understood. This thesis examined whether thinning and prescribed burning altered extractable LMWOA in O-horizon soils from the Lubrecht Experimental Forest. The study focused on lactic, propionic, glycolic, acetic, and formic acids measured in soils collected immediately before and approximately two weeks after the 2024 prescribed burn across four treatment categories: control, burn, thin, and thin+burn. The managed plots belong to a long-term experiment first treated in 2001-2002, whereas the control remained unmanaged …

Response Surface Modelling And Multi-Objective Optimisation Of Asphalt Binder And Mixture Properties Modified With Reclaimed Automotive Lubricants And Waste Glass Bottle Powder, Nura Shehu Aliyu Yaro, Jacob Adedayo Adedeji, Luvuno Nkosinathi Jele, Nasir Khan, Aliyu Usman, Jacob Olumuyiwa Ikotun

Journal of Sustainable Construction Materials and Technologies

Large volumes of reclaimed automotive lubricant (RAL) and waste glass bottle powder (WGBP) are disposed of inappropriately, causing serious environmental concerns. Furthermore, the paradigm shift towards sustainability in the pavement industry has prompted academics to investigate alternatives to conventional materials. As a result, one possible approach is to use these waste products as alternative materials in the asphalt pavement sector. This study investigated the combined use of RAL and WGBP as complementary modifiers, extending beyond the conventional single-modifier approaches reported in previous studies. Thus, in this study, response surface methodology (RSM) was utilised to optimise and predict the synergistic effects …

Design Of Air-Entrained Concrete For Airport Pavements Through Local Aggregate Utilization: Performance Optimization And Economic Analysis, Li Wentao, Rizwan Qadir, Arslan Mushtaq, Hilal Khan, Kamran Jillani

Journal of Sustainable Construction Materials and Technologies

Airport pavement construction in developing countries faces critical challenges balancing international performance standards with economic constraints, while limited research exists on optimizing air-entrained concrete mixes using locally sourced materials for cost-effective solutions. This study investigated the development of economical air-entrained concrete mix designs for airport pavements utilizing Pakistani aggregates and systematic cement content optimization. Comprehensive experimental evaluation included material characterization through petrographic analysis, alkali-aggregate reactivity assessment via accelerated mortar bar testing, and mechanical property development across cement contents from 360-450 kg/m3. Air entrainment was achieved through controlled admixture dosing while maintaining target slump of 50mm. Results demonstrated that locally sourced …

Molybdenum-Doped Zinc Oxide Nanocomposite For Sustainable Photoelectrocatalytic Degradation Of Dyes And Antimicrobial Activity, Samar A. Salim

Nanotechnology Research Centre

Mo-doped ZnO nanocomposite was synthesized by using auto-combustion method. X-ray diffraction patterns of prepared nanocomposite indicated effective construction of crystalline Mo/ZnO NCs with co-existence of MoO2 and ZnO in required weight ratio. XRD results revealed also that ZnO crystallite size decreased as Mo-doping concentration increased. The direct band gap reduced from 3.309 eV of (MZ-0) to 3.258 eV of (MZ-5), demonstrating a negative correlation with Mo-doping levels. The electrocatalytic activity of Mo/ZnO NCs was assessed by their capability to degrade Indigo Carmine (IC) and Murexide (ME) dyes, and their antibacterial properties were also evaluated. The electrocatalytic (EC) degradation efficiencies for …

Versatile Exoskeleton Control Paradigms For Agile Human Locomotion: Task-Agnostic And Stability-Augmented Assistance, Miao Yu

All Dissertations

Lower-limb exoskeletons have shown great potential for assisting human locomotion, but designing controllers that provide assistance across diverse locomotor tasks and under external perturbations remains a major challenge. Many existing controllers for steady-state walking rely on pre-defined reference trajectories, which constrain voluntary human motion and limit adaptability across tasks. Moreover, they usually assume stable walking, while their performance under unstable conditions remains largely unexplored. In addition, existing gait stability augmentation controllers are often reactive rather than proactive to unstable conditions. In this dissertation, we propose control frameworks that preserve voluntary human motion while addressing two major challenges: providing task-agnostic assistance …

Porous Hydrophobic Adsorbent Coatings For Carbon Dioxide Capture, Samuel Babatunde Olushola

Theses and Dissertations

This work presents the development of a porous, hydrophobic zeolite 13X coating for the separation of carbon dioxide (CO₂) from flue gas or natural gas. Zeolite 13X was combined with yeast, glucose, and sodium alginate as pore-forming agents, and with polytetrafluoroethylene (PTFE) and Polydimethylsiloxane (PDMS) as hydrophobicity-inducing agents to enhance water resistance while maintaining CO₂ access to the adsorbent. The study explored PTFE/13X mass ratios ranging from 0 to 2.33 to investigate the interplay between hydrophobicity and CO₂ uptake. The wettability of the coating was characterized by using a temporal water contact angle (WCA) measurement. Increasing …

Molecular Catalysts For Electrochemical Nitrogen Activation Toward Sustainable Ammonia Synthesis, Jin-Xiu Han, Hao Xue, Xian-Biao Fu

Journal of Electrochemistry

Homogeneous electrocatalytic nitrogen reduction reaction (NRR) provides a powerful framework to interrogate molecular nitrogen-fixation pathways under mild conditions. By tuning the metal center, ligand architecture, and reaction medium, these systems enable capturing key intermediates and delivering mechanistic insight at the molecular-level resolution. Nevertheless, advances remain constrained by highly reduced operating potentials, intense competition from the hydrogen evolution reaction (HER), limited durability in turnover, and inadequate long-term stability.

In this review, we take electron delivery to the molecular active site as the guiding principle for organizing homogeneous electrochemical N₂ activation and transformation. We classify reported systems into direct electron transfer …

Water-Driven Solid Electrolyte Interphase Governs Continuous-Flow Ammonia Electrosynthesis, Peng-Bo Liu, Sheng-Liang Zhai, Ji Huang, Zhong-Shuo Zhang, Jie Zeng, Shao-Feng Li

Journal of Electrochemistry

Flow-cell architectures have emerged as a powerful platform for continuous and stable lithium-mediated nitrogen reduction (Li-NRR), enabling ambient-condition electrochemical ammonia synthesis and offering a promising alternative to Haber-Bosch processes. However, Li-NRR is exceptionally sensitive to trace water, and even minor variations in water content can profoundly alter interfacial chemistry. Here, we systematically investigate how initial water concentration affects Li-NRR performance in a continuous-flow cell. Excess water drives the formation of a thick solid electrolyte interphase (SEI) layer, which may impede nitrogen access to metallic lithium and hinder lithium-ion transport. As a result, the ammonia Faradaic efficiency collapses from ~61% to …

Insertion Of Noble Metal Free Cathodic Catalyst Layer With Fe-N-C Catalyst For Boosted Performance Of Pemfc, Shi Zhou, Muhammad Tariq, Asif Nadeem Tabish, Muhammad Salman, Fan-Di Ning, Muhammad Rayyan Tayyab, Ran-Ran Peng, Meng-Geng Hao, Wen-Mu Li, Xiao-Chun Zhou

Journal of Electrochemistry

Economical Fe-N-C catalysts are considered as promising alternatives to platinum group metal catalysts for proton exchange membrane fuel cells (PEMFCs). Despite exhibiting robust activity on rotating disk electrodes, their performance within membrane electrode assemblies often experiences limitations, such as decreased O₂ diffusion, high H₂O₂ formation, low proton conduction, and a lower electron transfer number. In this study, key factors, including proton transport, electron conduction, and gas diffusion within air-breathing PEMFCs, have been investigated by adjusting cathode catalyst layer (CCL) compositions. From the experimental results, the optimal peak power density was obtained when the loading of Fe-N-C …

Design And Fabrication Of A Composite Torpedo Baseball Bat, Peyton A. Lee, Carter Mathison, Jaden J. Schwantz, Noah Misukanis, Cole V. Stalberger

Research & Creative Achievement Day

Observing current trends in Major League Baseball, there has been increasing interest in torpedo-style wood bats due to their unique weight distribution. Unlike traditional bat geometries, the torpedo design shifts more weight toward the hands, improving balance and allowing for greater control throughout the swing. This project applies the same concept using composite materials so that high school and college players can also have access to this design innovation. The proposed bat is constructed from carbon fiber reinforced polymer with an epoxy resin to create a lightweight and durable structure. The design aims to maintain the performance benefits of the …

Comparison Of Pfas-Free Hydrophobic Layer-By-Layer Coatings For Cellulosic Textiles: Evaluation Of Water Repellency, Mechanical Durability, And The Effects Of Fabric Construction, Elvira Isenzhulova, Radika Bhaskar

School of Design and Engineering Papers

Environmentally safe water-repellent coatings are urgently needed for the textile industry as an alternative to PFAS-based finishes. Challenges include development of coatings that are effective in imparting both water repellency and mechanical durability, with relatively simple synthesis to promote industry use. This study compared the performance and abrasion resistance of two different bio-based, layer-by-layer (LbL) self-assembled hydrophobic coatings for cellulosic fibers. Textile samples were coated with bilayers composed of negatively charged plant-derived carnauba wax and a positively charged component: either poly-L-lysine or lower-cost zinc oxide nanoparticles. To investigate the influence of surface microroughness on coating adhesion and performance, two different …

Analysis Of Factors Enabling Organisational Governance Maturity For The Technical Audit Function In Tanzania, George C. Haule

Tanzania Journal of Engineering and Technology (TJET)

The study aimed to identify key factors contributing to Organisational Governance Maturity (OGM) of the Technical Audit Functions (TAF) in Tanzania.  The study employed a sequential approach as a research design.  The first step was to collect and analyse literature studies to identify factors enabling the OGM of the TAF.  Next, a questionnaire was administered to one hundred twenty-eight (128) respondents from seven (7) TAFs to rank the key enabling factors that were identified from the literature that influence the OGM of TAF in Tanzania.  Using data from a questionnaire administered to 128 respondents, a two-step strategy was employed to …

Complex Systems Mapping Of Fiscal Growth Dynamics At Strategic Maritime Chokepoints Using Time-Series Slopes, Rahul Balamurugan, Preethi Nanjundan, Avichal Sharma

Northeast Journal of Complex Systems (NEJCS)

This study examines how maritime and trading states allocate public resources between defence, health, and economic growth around three strategic chokepoints the Strait of Malacca, the Strait of Hormuz, and the Suez Canal. The analysis extends the classic “guns versus butter” framing by treating defence and health spending as co-evolving components of an interconnected fiscal-growth system. Using World Development Indicators data (1999-2024), trend slopes are estimated for military spending (% of GDP), healthcare spending (% of GDP), and GDP growth (annual %). Two derived indicators are computed, a defence-to-health slope ratio (military slope/health slope) and a fiscal-balance proxy (health slope …