Engineering Science and Materials Commons^™

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 …

Development Of Microfluidic Device To Monitor The Contamination In Drinking Water Using Impedance Spectroscopy, Pornpipat Oupchan

Chulalongkorn University Theses and Dissertations (Chula ETD)

Microplastic contamination is a growing concern, as microplastics have been found in brain tissue and can enter the body through consumption. The objective of this research is to develop a microfluidic device to monitor microplastic particles by using electrical impedance spectroscopy principles. The device operates based on a flow-through principle. The configuration of electrode consists of copper-based cylindrical electrode with diameter of 300 micrometer and a center-to-center spacing of 2000 micrometer. The electrodes are designed to be replaceable. The microchannel has a rectangular cross-section with a width of 2000 micrometer and a height of 1000 micrometer. The microfluidic device was …

การทำความเย็นส่วนบุคคลโดยใช้วัสดุเปลี่ยนสถานะสำหรับบุคลากรที่สวมใส่ชุดป้องกันการติดเชื้อส่วนบุคคล, พรพุทธ วิสุทธิวัชรกุล

Chulalongkorn University Theses and Dissertations (Chula ETD)

ชุดป้องกันส่วนบุคคล (PPE) เป็นอุปกรณ์สำคัญที่ช่วยลดความเสี่ยงในการติดเชื้อของบุคลากรทางการแพทย์ อย่างไรก็ตาม การสวม PPE เป็นเวลานาน โดยเฉพาะในสภาพอากาศร้อนและชื้นอย่างประเทศไทย มักนำไปสู่การกักเก็บความร้อนในร่างกาย การระบายความร้อนลดลง และเกิดความไม่สบาย ความเหนื่อยล้า รวมถึงภาวะเครียดจากความร้อน งานวิจัยนี้จึงได้พัฒนาแบบจำลองชีวความร้อนอย่างง่าย (simplified bioheat model) โดยอ้างอิงโครงสร้างแบบจำลองแบบ passive ของ Fiala และเสริมด้วยการตอบสนองทางสรีรวิทยาแบบ active ที่จำเป็น เพื่อใช้ทำนายอุณหภูมิของร่างกายและประเมินความสบายทางความร้อนเมื่อสวม PPE ร่วมกับการระบายความร้อนด้วยวัสดุเปลี่ยนสถานะ (Phase Change Material: PCM) ผลการตรวจสอบความถูกต้องเทียบกับแบบจำลองอ้างอิงของ Fiala แสดงให้เห็นว่าแบบจำลองที่พัฒนาขึ้นมีความแม่นยำดี โดยมีความคลาดเคลื่อนของอุณหภูมิอยู่ภายใน ±0.2°C นอกจากนี้ผลการจำลองยังพบว่า PCM สามารถลดความเครียดจากความร้อนและเพิ่มความสบายทางความร้อนอย่างมีนัยสำคัญในช่วง 60 นาทีแรกของการทำงาน แม้ว่าประสิทธิภาพจะลดลงเมื่อ PCM หลอมละลายเต็มที่ก็ตาม ข้อจำกัดของงานวิจัยนี้ คือ แบบจำลองตั้งอยู่บนสมมติฐานของสภาวะอากาศร้อน (เริ่มต้นที่ 30°C) ทำให้ยังไม่สามารถแทนสภาวะอากาศเย็นได้อย่างสมบูรณ์ อีกทั้งไม่ได้พิจารณาการตอบสนองทางสรีรวิทยาระยะยาว เช่น ภาวะขาดน้ำ ความเหนื่อยล้า หรือความเครียดเชิงกลจากน้ำหนัก PCM ที่เพิ่มขึ้น ถึงแม้จะมีข้อจำกัดดังกล่าว แบบจำลองนี้ยังคงสามารถทำนายอุณหภูมิร่างกายและค่าความรู้สึกทางความร้อนแบบพลวัต (DTS) ได้อย่างมีประสิทธิภาพก่อนการใช้งานจริง จึงสามารถนำไปใช้เป็นเครื่องมือช่วยวางแผนระยะเวลาการทำงานที่ปลอดภัย และช่วยกำหนดปริมาณ รวมถึงตำแหน่งการติดตั้ง PCM ที่เหมาะสม ผลลัพธ์จากงานวิจัยนี้สามารถเป็นฐานข้อมูลสำคัญสำหรับการออกแบบชุด PPE ที่ปลอดภัย และช่วยลดภาระความร้อนสำหรับบุคลากรทางการแพทย์ในสภาพแวดล้อมร้อนชื้นได้ดียิ่งขึ้น

Enhancement Of Mechanical, Structural, And Electrical Properties In Advanced Composites And Vat Photopolymerized 3d Printing Nanocomposites, Poom Narongdej

CGU Theses & Dissertations

Advanced composites have gained significant attention across various industries, including aerospace, automotive, clean energy, and healthcare, owing to their exceptional mechanical properties and versatility. Fiber-reinforced polymer (FRP) composites, particularly those reinforced with carbon fibers, are extensively used as structural materials in spacecraft, aircraft, high-performance vehicles, and wind turbines due to their high strength-to-weight ratios, stiffness, durability, and tailorable mechanical characteristics. In healthcare, the advent of additive manufacturing (3D printing) has expanded the utility of advanced composites, enabling precise customization of components to meet patient-specific needs while offering design flexibility and ease of fabrication. Despite these advantages, several challenges hinder the …

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 …

Antibacterial, Self-Adhesive Guar Gum/Polyvinyl Alcohol/Tannic Acid Conductive Hydrogels For Flexible Strain Sensors, Noppanan Putdon, Somnuk Theerakulpistut, Rawit Jittham, Pornnapa Kasemsiri

Journal of Metals, Materials and Minerals

In this research, a multifunctional strain sensor with antibacterial properties and self-adhesion capabilities was developed using guar gum (GG), polyvinyl alcohol (PVA), and tannic acid (TA). The incorporation of TA into GG-PVA hydrogel-based strain sensors was investigated to evaluate its effects on mechanical and electrical properties, self-adhesion, and antibacterial activities. The anti-bacterial activities against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were enhanced with the increasing content of TA. The adhesive strength was observed in the range of 1.20 ± 0.10 kPa to 5.05 ± 0.23 kPa, and the values tended to increase as TA content increased. The …

Mechanochemical Synthesis Of Ni(Ii)-Tptz Complexes With Co-Ligands: Spectroscopy, Dft, And Biological Studies, Deepak Senapati, Anulipsa Priyadarshini, Debadutta Samal, P. Ramesh Babu, Satyanarayan Sahoo, Narayan Chandra Bera, Raghabendra Samantaray, Jagannath Panda, Rojalin Sahu

Journal of Metals, Materials and Minerals

New mixed-ligand Ni(II) complexes [Ni(tptz)(1,10-phen)] (1), [Ni(tptz)(2-Mimd)2] (2), and [Ni(tptz)Imd)2] (3) were synthesized via a green, solvent-free mechanochemical approach using ball milling. The primary ligand used was 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz), with secondary ligands being 1,10-phenanthroline, 2-methyl imidazole, and imidazole, respectively. Structural characterization by IR, UV-Visible, photoluminescence spectroscopy, and powder X-ray diffraction, supported by DFT calculations, revealed a distorted square planar geometry for complex 1 and distorted tetrahedral geometries for complex-2 and complex-3. Notably, bathochromic shifts in the UV-Vis spectra confirm metal-ligand charge transfer transitions and extended π-delocalization. Powder XRD analysis determined average crystallite sizes of 17.86 nm (1), 25 nm (2), …

Liquid-Liquid Extraction Of Nd(Iii) Using [P66614][Cy272] Ionic Liquid, Prasanjit Das, Kali Sanjay, Niharbala Devi

Journal of Metals, Materials and Minerals

This study explores the extraction of Nd(III) from synthetic solutions using the ionic liquid [P66614] [Cy272]. Key extraction parameters, including the effect of phase contact time, initial pH, salting-out agents, extractant concentration, and temperature, were systematically optimized. Results revealed that a phase contact time of 15 min, an initial pH of 2.14, and 0.2 mol∙L‒1 NaCl as a salting-out agent and extractant concentration of 0.015 mol∙L‒1 [P66614][Cy272], achieved maximum extraction efficiency of 99.7%. Thermodynamic analysis confirmed the process is to be exothermic, spontaneous, and entropy-driven, highlighting the strong complexation between Nd(III) and the ionic liquid [P66614][Cy272]. Stripping tests revealed that …

Evaluation Of Practical Methods To Determine If A Karst Creek Is Gaining Or Losing: Case Study Of Leith Creek, Elizabeth Jones

Graduate Theses/Dissertations

Karst landscapes are abundant in Missouri, with features such as caves, springs, and sinkholes that form through the dissolution of limestone. Leith Creek is a small stream in Polk County, Missouri fed by two springs and the shallow unconfined Springfield Plateau aquifer, a highly karstified aquifer which is made up of limestone and minor interbedded shale-mudstone units. To determine if Leith Creek is gaining or losing, stream flow, water chemistry and temperature sensors were monitored. Stream flow results required multiple visits to take measurements while temperature sensors required two visits, one to install the dataloggers and another to remove the …

Phase-Field Method Of Fracture In Fiber-Reinforced Polymer Composites: Theory, Modeling, And Validation, Akash Kumar

Dissertations, Master's Theses and Master's Reports

Fiber-reinforced polymer composites (FRPCs) are widely used in aerospace, automotive, and civil engineering due to their high specific strength, stiffness, and durability. However, their anisotropic and heterogeneous nature makes fracture prediction challenging, with damage modes classified as intralaminar failure (matrix cracking, fiber breakage, fiber-matrix debonding) and interlaminar delamination. Delamination, driven by weak through-thickness strength and high interlaminar stresses, is a predominant failure mechanism in FRPCs. While cohesive zone models (CZMs) are commonly used for delamination, they are computationally expensive and inefficient for capturing intralaminar fractures where crack paths are unknown. To address this, we developed a unified phase field-based cohesive …

Controlling Nitrogen Pickup During Induction Melting Of Ultrahigh-Strength Cr-Ni-Mo-V Steels, Kingsley T. Amatanweze, Viraj A. Athavale, Mario F. Buchely, Laura N. Bartlett, Ronald J. O'Malley, Daniel M. Field

Materials Science and Engineering Faculty Research & Creative Works

Nitrogen pickup during air induction melting can result in porosity and a loss of fracture toughness in ultrahigh-strength quenched and tempered steel castings. Nitrogen atoms are easily adsorbed into liquid steel upon exposure to the air, and argon shrouding alone has limited effectiveness. Previous studies have shown that proper charge sequencing and maintaining a high amount of dissolved oxygen in the melt prior to tapping and deoxidation can limit nitrogen pickup in the melt. In the current study, the effect of melt practice and charging procedure on nitrogen pickup was studied as a function of hold time in a series …

Parametric Analysis Of Water Jet Descaling Efficiency Of Reheated Continuously Cast Thin Slab, Tochukwu P. Ojiako, Mario F. Buchely, Simon Lekakh, Ronald J. O'Malley, Richard Osei, Taha Tayebali

Materials Science and Engineering Faculty Research & Creative Works

Efficient oxide scale removal is critical for maintaining surface quality and process efficiency in steel manufacturing. This study optimizes water jet descaling by evaluating the performance of flat and rotary jet nozzles under varying process parameters. Using a combined approach of experimental analysis and computational fluid dynamics, it investigates the influence of pressure (138–275 bar), lead angle (0°, 15°, 25°), working distance (50–100 mm), and spray angle (15°–25°) on descaling efficiency. Findings indicate that flat jet nozzles achieve superior performance at short working distances due to concentrated impact forces, while rotary jet nozzles sustain efficiency over extended distances through dynamic …

Effect Of Gating Design On Filling And Inclusion Control In An Al-Killed Cr-Mo-Ni Steel, Kingsley T. Amatanweze, Koushik Balasubramanian, Soumava Chakraborty, Viraj A. Athavale, Mario F. Buchely, Laura N. Bartlett, Ronald J. O'Malley, Daniel M. Field, Krista R. Limmer, Katherine M. Sebeck

Materials Science and Engineering Faculty Research & Creative Works

The effect of gating system design on the inclusion population and size distribution in an aluminum-killed low-alloy advanced high strength steel casting was studied. A mold with four different gating systems: pressurized and non-pressurized with side risers, naturally pressurized with a side riser, and naturally pressurized with a top riser, was designed using computational fluid dynamics and solidification software. The design allowed inclusion populations in castings produced with each gating system to be compared during the same pouring event. Samples taken from different positions just below the top surface of each casting were analyzed using an SEM/EDS system with automated …

Effects Of Soil Properties On Cp Performance, Cecilia Segretario

Williams Honors College, Honors Research Projects

This research aims to evaluate the affect of various soil properties on the effectiveness of cathodic protection (CP) in preventing underground pipeline corrosion. Metal coupons of common pipeline materials with applied CP will be mounted in several separate controlled soil environments to manipulate real world underground corrosion scenarios. Each soil environment will have different physical properties by mixing the soil with a prepared chemical solution. The physical properties to be evaluated include pH, resistivity, and moisture content. At the end of a corrosion duration, weight loss method will be used to evaluate the corrosion rate over that period. Additionally, the …

Cochlear Electrode Insertion Training Model, Sarah Powell, Kaelyn E. Kraley, Nathan J. Smith

Williams Honors College, Honors Research Projects

Cochlear implant surgery is a delicate procedure performed by Otolaryngologists (ENTs) to implant an electronic device into the inner ear to provide a sense of sound for people who are profoundly deaf or hard of hearing. The current practices of training involve cadavers and 3D-printed models. Cadavers are commonly used but are expensive, single-use, and do not provide visual and haptic feedback, which are essential for medical students. 3D printed models are less commonly used and are hard to fabricate and not as realistic. If medical students are not properly trained for this delicate procedure, then risks are significantly increased …

Ab Initio Simulations For Oxidation Of An Ultra-High Temperature Ceramic (Hfb2), Wesley I. Black

Browse all Theses and Dissertations

Ultra-High Temperature Ceramics are a class of ceramics that possess high strength and melting points in excess of 3000°C. These ceramics are promising for aerospace applications, where materials need to endure high-temperature and high-stress environments. Utilizing ab initio simulations, this thesis research focuses on the atomistic details of oxidation for a typical ultra-high temperature ceramic material, namely hafnium diboride. The simulations provide energy barriers for transition from the initial to final structures via transition states on the (0 0 0 1) surface. These result in estimates for reaction rates and other thermodynamic features that are essential for assessing applicability under …

Design And Development Of A Rapid Tensile Quench Rig, Tyler Jewell, Justin Naylor

Williams Honors College, Honors Research Projects

This report outlines the design process and implantation of a tensile quenching rig that incorporated forced convection and a frequency generator. When any metal is quenched, a vapor barrier forms around it. When this happens, it limits the heat flux that may occur until the barrier turns into just nucleate boiling. The vapor barrier acts as an insulator and causes the heat flux to fluctuate, causing uneven hardening which would limit the use of some materials. To combat this effect, we are trying to use forced convection, and something new, which is adding high frequency waves into the quenching process. …

Study Of Fiber-Loaded Slurries For Ceramic Matrix Composite Fabrication By Additive Manufacturing, Gaspard Matondo

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We studied the additive manufacturing of an alumina-matrix composite reinforced with alumina fibers using the Admatec Admaflex 3D printer, which utilizes digital light processing technology. Oxide-oxide composites are composite materials in which both the matrix and the reinforcing element are ceramic oxides. Monolithic alumina ceramic exhibits a good combination of thermal and mechanical properties, including thermal shock resistance, high melting point, thermal oxidation resistance, good thermal conductivity, hardness, and mechanical strength. However, it is very brittle. Introducing alumina fiber as a reinforcing material into the alumina matrix is expected to enhance mechanical properties, particularly toughness, making the ceramic matrix composite …