Engineering Commons^™

High-Temperature Performance Of Alloyed Cast Irons And Cr/Ni Austenitic Steels—An Overview And Discussion, Simon N. Lekakh, Mei Li, Larry Godlewski

Materials Science and Engineering Faculty Research & Creative Works

Fe-based cast alloys, including cast irons and steels, have been used in service at a wide range of mechanical and thermal load in oxidizing environment. Special alloying practices can be used to improve high temperature performance of Fe-based cast alloys in an oxidizing atmosphere. At elevated temperatures, alloying elements can produce a protective interface layer which prevents oxidant penetration into the metal matrix. However, a combination of thermo-mechanical loads along with surface oxidation can decrease the materials integrity by destroying the stable protected interface limiting the range of working parameters and lifetime performance of the material. This overview aims to …

Flexural Strength Of (Hf,Nb,Ta,Ti,Zr)B2–(Hf,Nb,Ta,Ti,Zr)C High-Entropy Dual-Phase Ceramics, Rubia Hassan, William G. Fahrenholtz, Gregory E. Hilmas, Jeremy Watts

Materials Science and Engineering Faculty Research & Creative Works

The room and elevated temperature flexural strengths were measured for (Hf,Nb,Ta,Ti,Zr)B2–(Hf,Nb,Ta,Ti,Zr)C high-entropy dual-phase ceramics. The fracture of ceramics originated from two distinct flaw populations that were either surface defects introduced during specimen preparation or volume defects introduced during processing. The average strength at room temperature was 638 ± 94 MPa with individual bars strengths as high as ∼800 MPa. At 1800°C, average strength increased to 786 ± 265 MPa with individual bar strengths as high as ∼1050 MPa. Above 1800°C, creep dominated resulting in deformation of the bars without fracture. The fracture mode changed from completely trans granular at room …

Molecular Dynamics Simulations Of Key Parameters On Thermal Properties Of Carbon Nanotube Modified Epoxy Composites, Lida Najmi

Electronic Theses and Dissertations

The application of carbon nanotube (CNT)-reinforced epoxy matrix composites (CRECs) has attracted extensive attention in various industrial sectors due to the significant improvement of material properties imparted by CNTs. The thermal behavior of these nanocomposites is governed by complex heat transfer mechanisms operating at different scales, resulting in a complex relationship between the effective thermal response and the microstructural characteristics of the composite. In this study, molecular dynamics (MD) simulations were used to investigate the thermal conductivity of CRECs, focusing on the effects of key parameters such as the length and volume fraction of CNTs, the degree of cross-linking within …

A Comprehensive Review Of Piezoelectric Pvdf Polymer Fabrications And Characteristics, Nadia Ahbab, Sidra Naz, Tian-Bing Xu, Shihai Zhang

Mechanical & Aerospace Engineering Faculty Publications

Polyvinylidene fluoride (PVDF) polymer films, renowned for their exceptional piezoelectric, pyroelectric, and ferroelectric properties, offer a versatile platform for the development of cutting-edge micro-scale functional devices, enabling innovative applications ranging from energy harvesting and sensing to medical diagnostics and actuation. This paper presents an in-depth review of the material properties, fabrication methodologies, and characterization of PVDF films. Initially, a comprehensive description of the physical, mechanical, chemical, thermal, electrical, and electromechanical properties is provided. The unique combination of piezoelectric, pyroelectric, and ferroelectric properties, coupled with its excellent chemical resistance and mechanical strength, makes PVDF a highly valuable material for a wide …

Design Of Aluminum-Copper Alloy With Scandium In Solution, Austin M. Depottey

Dissertations, Master's Theses and Master's Reports

The 2xxx series of precipitation-strengthened aluminum-copper alloys are commonly used in high-temperature applications (up to 300°C) where lightweight metals are required. Scandium additions to aluminum-copper alloys have gained recent academic interest due to improved high-temperature mechanical properties, by forming coarsening- resistant Al3Sc dispersoids and stabilization of θ′ precipitates. However, gaps in knowledge about the effects of scandium present a challenge to successful commercialization of aluminum-copper-scandium alloys. This work seeks to explore these knowledge gaps and ultimately design and test a commercially feasible aluminum- copper alloy with scandium. To better understand the processing conditions required to avoid the detrimental W-phase (Al8Cu4Sc), …

Machine Learning Design And Experimental Production Of Recycled Aluminum Alloys With Magnesium And Iron, Skylar Patten

Dissertations, Master's Theses and Master's Reports

Recycling aluminum saves up to 95% of the energy required for primary production but introduces impurities such as iron that limit alloy performance. The Al-Mg-Fe system, though commercially used, remains underexplored. This work applies machine learning with Multi-Objective Bayesian Optimization (MOBO) using Thermo-Calc simulations to design Al-Mg-Fe-Si-Cu-Zn alloys with improved castability and reduced porosity. The optimization targeted freezing range, shrinkage, drag coefficient, and microstructural parameters, identifying compositions with high Mg, Si, and Cu and low Zn as optimal. Predicted alloys were experimentally cast and characterized, with yield strengths exceeding 95 MPa and elongation comparable to commercial 319 aluminum in the …

Nanomaterial-Enabled Enhancements In Thylakoid-Based Biofuel Cells, Amit Sarode, Gymama Slaughter

Center for Bioelectronics Publications

Thylakoid-based photosynthetic biofuel cells (TBFCs) harness the inherent light-driven electron transfer pathways of photosynthesis to enable sustainable solar-to-electrical energy conversion. While TBFCs offer a unique route toward biohybrid energy systems, their practical deployment is hindered by sluggish electron transfer kinetics, unstable redox mediators, and inefficient interfacing between biological and electrode components. This review critically examines recent advances in TBFCs, with a focus on three key surface engineering strategies: (i) incorporation of nanostructured materials to enhance electrode conductivity and surface area; (ii) application of redox mediators to facilitate charge transfer between photosynthetic proteins and electrodes; and (iii) functional exploitation of individual …

Thermo-Rheological And Tribological Properties Of Low- And High-Oleic Vegetable Oils As Sustainable Bio-Based Lubricants, Abiodun Saka, Tobechukwu K. Abor, Anthony C. Okafor, Monday U. Okoronkwo

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Vegetable oil-based lubricants have attracted increased research attention in recent decades as sustainable alternatives to conventional petroleum-based lubricants in metal machining. However, more studies are required to fully elucidate the thermo-rheological and tribological properties. This study presents an investigation of the thermo-rheological and tribological properties of different vegetable oils, including low- and high-oleic soybean oil, high-oleic sunflower, safflower, and canola oils. The lubricity, and evolution of viscosity and thermodynamic properties as a function of temperature were investigated to obtain important parameters including the viscosity index, flow behavior index, flow activation energy, specific heat capacity, thermal conductivity, coefficient of friction, contact …

Solid Loading Effects On The Assembly Of Alumina Particles In Aqueous Suspensions Due To The Dielectrophoretic Forces, Sivakumar Chithamallu, Rohan Kiran Parai, Dipankar Ghosh

Mechanical & Aerospace Engineering Faculty Publications

Current work in situ investigated the mechanisms of the interparticle interactions that evolve in dilute aqueous alumina suspensions subjected to alternating current (AC) electric field and the effects of solid loading of suspensions. The interactions were investigated for alumina suspension compositions in the 0.005‒0.04 vol.% solid loading range. Field‐induced interactions evolved via particle motion and dynamic assembly, chain formation parallel to the direction of the applied field and chain growth, chain cross‐linking, and chain thickening. The evolution time of each of those events was rapidly accelerated with solid loading. While chain cross‐linking was negligible in low solid loading suspensions, a …

Flexural Response Of Inflatable Drop-Stitch Panels, Alex J. Watterson

Open Access Master's Theses

All CUI (Controlled Unclassified Information) is U.S. government property and has been removed from this thesis.

Evaluation Of Polymer Coated Fabrics Subjected To Various Multiaxial Stress States, Shane Marx

Open Access Master's Theses

All CUI (Controlled Unclassified Information) is U.S. government property and has been removed from this thesis.

Atomistic Calculations Characterizing Thermodynamic And Mechanical Properties Of High Entropy Alloys, Sarah O'Brien

Theses and Dissertations--Chemical and Materials Engineering

High entropy alloys (HEAs) are an exciting new class of materials. HEAs combine multiple elements in concentrations ranging from 5% to 35%. The large variation in concentrations increases the alloy’s entropy, stabilizing it. The stabilization is due to both an increased configurational entropy and increases the vibrational entropy when the alloy is at higher temperatures. This was seen for both MoNbTaW and FeNiMoW by combining the atomistic techniques: density functional theory (DFT) and density functional perturbation theory (DFPT). For MoNbTaW, the composition plays a large role in stabilizing the alloy over the configuration of elements. For the three-phase alloy, FeNiMoW, …

Analysis Of Ptfe Radial Lip Seals For Wheel Bearing Applications, Madison Vogt

Theses and Dissertations--Mechanical and Aerospace Engineering

A numerical analysis was conducted to investigate the viscoelastic effects of nonlinear materials on the sealing zone and contact pressure distribution of radial lip seals in a conventional geometric topology. The use of nonlinear materials in radial lip seal applications is desirable to improve operation and reliability of rotating machinery due to their high operating temperatures, chemical compatibility, and low friction coefficients. Examples include, but are not limited to, seals within industrial air compressors, turbine engines, aircraft landing systems, chemical processing equipment, and Freon pumps. This work focuses on analyzing the nonlinear viscoelastic response of pure Polytetrafluoroethylene (PTFE) and PTFE …

Growth Kinetics And Stability Of Metal Halide Perovskite Nanocrystals: Influence Of Stirring Speed And Water Exposure, You-Lin Huang

Theses and Dissertations--Mechanical and Aerospace Engineering

Cesium lead bromide (CsPbBr₃) perovskite nanocrystals (NCs) have garnered significant interest due to their exceptional optoelectronic properties, including high photoluminescence quantum yield, tunable bandgap, and excellent carrier dynamics. These attributes make them promising candidates for applications in light-emitting diodes, photovoltaics, and sensing technologies. However, optimizing their synthesis and improving their environmental stability remain critical challenges. This dissertation explores the growth kinetics of CsPbBr₃ NCs, focusing on the effects of stirring speed and water exposure on their structural and optical properties.

The synthesis of CsPbBr₃ NCs was performed using both mechanochemical (MC) and antisolvent methods, enabling an …

Fabricating Silver-Ceria Polymer Nanocomposite Scaffolds For Biomedical Therapeutic Applications, Shreya S. Pawar

Honors Undergraduate Theses

Improper healing of bone fractures and limited regeneration of bone following bone tumor resection remain a prevalent complication worldwide. Long-term effects of this include joint instability, limited movement, and arthritis. Bone infections (osteomyelitis), reactive oxygen species (ROS) generation via excessive inflammation, and underlying conditions such as osteoporosis can contribute to suboptimal bone tissue regeneration. ROS accumulation stimulates osteoblast apoptosis, while promoting osteoclast differentiation. These processes inhibit mineralization and osteogenesis. Conventional therapeutics involve the utilization of drugs and bone grafts. However, these approaches pose limitations and can result in subsequent complications. Microbial infections, ROS accumulation, and excessive inflammations are factors that …

Polymeric Nanocomposites-Based Advanced Coatings For Antimicrobial And Antiviral Applications: A Comprehensive Overview, Rachid Amrhar, Jaspal Singh, Mostafa Eesaee, Pascal Carrière, Alireza Saidi, Phuong Nguyen-Tri

Revues de littérature, synthèses de connaissances

The rise in microbial infections and viral outbreaks has accelerated the development of advanced antibacterial and antiviral coating that effectively minimize infection risks. Amidst rising global health concerns due to infectious diseases, these coatings have emerged as vital solutions for surface protection across various settings. This review focuses on the recent development and in-depth analysis includes synthesis process, inactivation mechanism in photoreactive antimicrobial and antiviral bio-coatings. This review comprehensively explores the development of different nanocomposite materials, including polymers based on metal oxide nanoparticles, metal nanoparticles, graphene-based materials, and organic-inorganic composites. Their practicality and compatibility with diverse surfaces such as ceramics, …

Improving The Figure Of Merit In Iron-Vanadium-Aluminium Thermoelectric Alloy System Guided By Computational Modeling, Tao Fang

Dartmouth College Ph.D Dissertations

Thermoelectric materials can convert a thermal gradient to electricity. Currently, commercialized Bi₂Te₃ is brittle and expensive, which restricts the usage of this material. Compared to other thermoelectric materials, Fe₂VAl is cost-effective, stable and more robust mechanically. However, the figure of merit (zT) had been much lower than Bi₂Te₃. In this thesis, our main goal is to improve the figure of merit in Fe₂VAl system guided by computational modeling. We will start the discussion by presenting the Ge doped Fe₂VAl sample with record thermoelectric figure of merit value. …

Photocatalytic Performance Of Ba₀.₈Ca₀.₂Tio₃ Composite For Norfloxacin Removal In Aqueous Solutions, Raj Mohanty, Swayam Aryam Behera, Asima Subhadarshini, Binita Nanda, P. Ganga Raju Achary

Journal of Metals, Materials and Minerals

This study investigates the degradation of norfloxacin using a Ba0.8Ca0.2TiO3 (BCTO) perovskite composite synthesized via a simple solid-state method. Variety of characterization techniques, including photoluminescence spectra, powder X-Ray Diffraction, UV-Vis Diffuse Reflectance Spectra, FE-SEM and Fourier-Transform Infrared spectra confirm the structural and optical properties of BCTO. Electrical characterization further elucidates its conductive properties. The BCTO composite demonstrates an impressive 87% degradation rate of norfloxacin, attributed to its reduced electron-hole recombination, enhanced light harvestation, and improved charge carrier mobility. Kinetic studies indicate that the degradation process adheres to a pseudo-first-order model, with BCTO outperforming both pure BaTiO3 and conventional photocatalysts. These …

Improving The Mechanical Performance Of 45s5 3d Scaffolds Through The Particles Of Barium Titanate Ceramics, Surirat Yotthuan, Usanee Pantulap, Nuttawan Sawangboon, Ornuma Tungsanguan, Ekarat Meechoowas, Kansiree Kaewmorakot, Nathaporn Uthaichai, Theerachai Bongkarn

Journal of Metals, Materials and Minerals

Bioglass® 45S5 is widely used in bone tissue engineering due to its excellent bioactivity. However, its low mechanical strength remains a major limitation. In this study, 25 wt% barium titanate (BaTiO3; BT) was incorporated into 45S5 scaffolds to improve mechanical performance and modulate bioactivity. The 3D scaffolds were fabricated using the foam replication method and exhibited interconnected porosity, with average pore sizes of 471 ± 94 μm (45S5) and 598 ± 58 μm (45S5/BT25), closely resembling human bone. The addition of BT increased the density and compressive strength of the scaffolds to 2.89 ± 0.18 g∙cm‒3 and 2.0 ± 0.2 …

Synthesis And Characterization Of Silica Nanoparticles From Solar Panel Glass Cullet, Pathomporn Ussawanawachat, Nithiwach Nawaukkaratharnant, Apirat Theerapapvisetpong

Journal of Metals, Materials and Minerals

The rapid growth of solar energy as a renewable resource has led to a significant increase in discarded solar panels. Recycling their glass components, especially fine cullet fragments, remains a major challenge due to impurity levels and processing limitations. This study proposes a sustainable approach to recycle solar panel glass cullet into high-purity silica nanoparticles using alkali fusion followed by acid precipitation. Process conditions including cullet to NaOH ratio, fusion temperature, and surfactant addition were optimized. The highest silica yield of 60.26% was achieved at a 1:1.4 cullet to NaOH ratio and 500℃. Polyethylene glycol (PEG 1000) was used as …

Laser Ablation Behavior And Ablation Threshold Of Entropy-Controlled Perovskite Coatings, Shuo Wang, Junyang Lu, Mengqing Zhang, Jiayi Zheng, Tong Zhang

Journal of Metals, Materials and Minerals

The protection threshold of laser ablation resistant materials lags behind the development of laser power density. Single-functional laser ablation resistant materials can no longer meet the practical needs. High-entropy perovskites with infinite chemical composition, tunable bandgap structure, and efficient thermal management capabilities provide new ideas for developing novel high-reflectivity and low-thermal-conductivity multifunctional laser ablation resistant materials. Herein, leveraging these unique advantages of high-entropy perovskites in optics and thermodynamics, four entropy-controlled perovskite coatings, Ba(Zn1/2Ta1/2)O3 (BZTO), Ba(Zn1/3Ta1/3Nb1/3)O3 (BZTNO), Ba(Zn1/4Ta1/4Nb1/4Ti1/4)O3 (BZTNTO) and Ba(Zn1/5Ta1/5Nb1/5Ti1/5Zr1/5)O3 (BZTNTZO) are designed. Through time-dependent laser ablation experiments, the optical and thermal properties are comprehensively evaluated. And laser ablation behavior …

Downstreaming Of Natural Materials Huta Ginjang Quartz Sand Doped With Nd2o3 For Laser Medium Application, Juniastel Rajagukguk, Jakrapong Kaewkhao

Journal of Metals, Materials and Minerals

The QSBoBa glasses with chemical formula 10 Quartz sand + (50-x) B2O3 + 10BaO + 30Na2O + xNd2O3 (x = 0, 0.5, 1, 1.5, and 2 mol%) were prepared by a conventional melt-quenching technique. The successfully fabricated glass samples will be analyzed based on their physical, structural, optical and luminescent properties. The XRD and FTIR spectra have been included to observe the complete structural properties. Optical absorption spectra revealed several characteristic transitions, with a prominent hypersensitive transition 4I9/2→4G5/2 at 584 nm, indicating an increasing asymmetry and disorder at higher Nd3+ concentrations. The photoluminescence emission spectra demonstrated strong radiative transitions of …

Crack Development Of Electroplated Niw Alloys And Their Wettability And Tribological Properties, Jidsucha Darayen, Suwat Ploypech, Martin Metzner, Claudia Beatriz Dos Santos, Petch Jearanaisilawong, Yuttanant Boonyongmaneerat

Journal of Metals, Materials and Minerals

This study investigates how sodium tungstate concentration (20–46 wt.%) and current density (40–60 A/dm²) affect the microstructure, wettability, mechanical properties, and tribological behavior of electrodeposited Ni-W coatings. Results show that increasing current density markedly raises crack density (from <100 to >400 cracks/cm²), while tungstate concentration has minimal effect. XRD confirms Ni-W solid solution formation, with higher tungsten content refining grains and increasing hardness—peaking at 900 HV at 50 A/dm² (an 80% rise from 500 HV at 40 A/dm²). However, excessive stress at 60 A/dm² leads to microcracking and hardness plateauing (~650–700 HV). Higher crack density improves wettability (contact angle ~17°), enhancing lubricant …

Upcycled Waste-Derived Triboelectric Nanogenerator For Sustainable Energy Harvesting, Archana Panda, Basanta Kumar Panigrahi, Subhendu Pati, Sunit Gourav Mohanty, Kushal Ruthvik Kaja

Journal of Metals, Materials and Minerals

The proliferation of disposable paper-based materials in laboratories has raised significant environmental concerns due to their rapid discard and accumulation. This study explores the upcycling of commonly discarded laboratory waste, specifically butter paper and polyurethane (PU) foam, into a single-electrode triboelectric nanogenerator (TENG) for mechanical energy harvesting. The fabricated device employs butter paper as the positive triboelectric layer and PU foam as the negative layer, with an aluminium tape electrode. Electrical tests reveal a peak voltage of 21 V and current of 47 nA, reaching a maximum power of 438 nW at 500 MΩ load. The TENG demonstrates stable performance …

The Effects Of Starting Microstructure On The Results Of Double Intercritical Annealing Process Of 0.107%C-2.39%Mn-0.453%Si Dual Phase Steel, Wichayut Chumoung, Nithi Saenarjhan

Journal of Metals, Materials and Minerals

This study investigates and compares the effects of the starting microstructure on the double intercritical annealing (DIA) process on the microstructure and mechanical properties of 0.11%C-2.39%Mn-0.45%Si dual phase steel. The specimens were austenitized, followed by water quenching (WQ) or air cooling (AC), then DIA at 730°C. For the WQ method, high cooling rate results in the formation of a high strength martensitic structure. Conversely, AC method yields a moderate cooling rate, forming a bainitic structure. After single intercritical annealing (SIA), the microstructure transformed into ferrite and martensite. WQ method specimens contain high stress concentration, leading to earlier recrystallization compared to …

Effects Of Thickness On The Performance Of Sno2 Gas Sensors Using Low-Temperature Co-Fired Ceramic, Montri Aiempanakit, Kittiyaporn Singsumphan, Chutima Nakmuk, Cheewita Suwanchawalit, Manatsawee Srirak, Kata Jaruwongrungsee, Anurat Wisitsoraat, Monrudee Liangruksa, Chawarat Siriwong

Journal of Metals, Materials and Minerals

This study develops SnO2-based gas sensors integrated with a low-temperature co-fired ceramic (LTCC) micro hotplate for ethanol detection. SnO2 nanoparticles were synthesized using a simple precipitation method, and sensing layers with varying thicknesses around 0.24 µm, 0.71 µm, and 1.20 µm were applied to evaluate their influence on performance. The results show that the optimal configuration is a 0.71 µm layer, offering high sensitivity, fast response, and efficient recovery. Operating at a low voltage of 3.2 V, the sensors exhibit low power consumption, suitable for portable and battery-operated applications. The gas-sensing mechanism relies on changes in resistance due to interactions …

Atmospheric Corrosion Of Hot Dip Galvanized Structural Steel Exposed To The Tropical Climate Of Thailand, Adithep Bunphot, Pakawat Sancharoen, Somnuk Tangtermsirikul, Taweep Chaisomphob

Journal of Metals, Materials and Minerals

Hot dip galvanized steels were tested in the atmospheric tropical climate environments of Thailand for 12 month from March 2021 to March 2022. Three locations were studied, i.e. a rural area at Saraburi in the central part, an industrial area at Chonburi in the eastern part, and a coastal/urban area at Songkhla in the southern part of Thailand. The thickness loss of the galvanized steel samples was measured by the weight loss method. Types of corrosion products observed on the samples were zincite, wulfingite, hydrozincite, and simonkolleite. All of them were found on the sample at Songkhla. Three of them, …

Lactic Acid-Assisted Complexation For Enhanced Lithium Extraction And Its Application To Spent Libs, Sibananda Sahu, Niharbala Devi

Journal of Metals, Materials and Minerals

A novel approach for complexing lithium with lactic acid to enhance extraction efficiency and its application to spent LIBs was proposed in this study. Key parameters influencing the extraction were systematically examined, including lactic acid concentration, pH of the aqueous phase, concentration of extractant, diluent selection, phase ratio between organic and aqueous phase, and stripping efficiency. Lithium extraction showed a remarkable improvement, rising from 16% to 43%, as the lactic acid concentration enhanced from 0.01 mol∙L‒1 to 1.0 mol∙L‒1. This was achieved using D2EHPA (0.1 mol∙L‒1)  at a maintained pH of 6.5. Maximum lithium extraction of 84.5% was observed at …

Development Of Ceramic Based Novel Materials For Application In Low Temperature Solid Oxide Fuel Cell (Ltsofc) – A Critical Review, Kaliappan Tamilselvan, Arputharaj Samson Nesaraj

Journal of Metals, Materials and Minerals

In the field of renewable energy, fuel cell research has emerged as a promising source of energy for the future. Fuel cells utilize fuels more efficiently compared to other energy generation systems. Solid oxide fuel cell (SOFC) systems are gaining prominence due to their applications in military operations, mobile power supplies, and stationary power generation. Significant research efforts are being made to lower the operating temperature of SOFCs from 1000℃ to approximately 600℃, leading to the development of low-temperature solid oxide fuel cells (LTSOFCs). This is being achieved by selecting alternative electrode and electrolyte materials, particularly ceramics, to enhance their …

The Effect Of Asphalt Emulsion On The Properties Of Fly Ash Based Geopolymers, Natcha Prommityat, Chiravoot Pechyen, Pitak Laoratanakul, Benya Cherdhirunkorn

Journal of Metals, Materials and Minerals

This research aimed to study the effect of asphalt emulsion (AE) on the properties of fly ash based geopolymers. Solid waste materials used for the production of geopolymer were coal fly ash (FA) 70 wt% and bagasse ash (BA) 30 wt%. Alkaline solution used for the geopolymerization reaction was the mixture of 10 M NaOH and Na2Sio3

with the ratio of 1:2. The liquid and solid (L/S) ratios of 0.6, 0.7 and 0.8 were prepared. The AE of 1 wt%, 3 wt% and 5 wt% were added into the raw materials mixtures. Then, the mixed slurry was casted into a …