Materials Science and Engineering Commons^™

Aerosol Synthesis Of Tungsten Bronze Particles For Nir Shielding, Hao Tu

Theses and Dissertations

This dissertation emphasizes the need for efficient energy use in buildings and transportation due to global warming and the energy crisis. It suggests that improving energy efficiency can help reduce energy consumption and emissions and support sustainability. The dissertation introduces various transparent materials that can block near-infrared (NIR) radiation from solar radiation to save energy and money, and it highlights the growing market value of such products. The dissertation compares tungsten bronze with other NIR shielding materials and shows its advantages. The dissertation introduces a cheap and environmentally friendly method for continuously producing tungsten bronze particles via aerosol synthesis. Particle …

Fabrication And Optical Properties Of Two-Dimensional Transition Metal Dichalcogenides, Manpreet Boora

Dissertations, Master's Theses and Master's Reports

Two-dimensional layered materials such as graphene and transition metal dichalcogenides have gained a lot of attention because of their distinctive chemical, optical, and electronic properties. Transition metal dichalcogenides can have a tunable bandgap in the range of 1 − 3 eV (visible), which enables their applications in ultrathin field effect transistors, photovoltaics, sensors, and optoelectronic devices. They exhibit an indirect-to-direct band gap transition when thinned down from bulk to a single layer. They show strong photoluminescence, electron–photon interaction, valley pseudospin, nonlinear optical response, and lack of dangling bonds. Many exotic phenomena appear when materials are thinned to nanoscale size because …

Study Of Nanocomposite Materials Using Molecular Dynamics, Prashik Sunil Gaikwad

Dissertations, Master's Theses and Master's Reports

There is an increase in demand for new lightweight structural materials in the aerospace industry for more efficient and affordable human space travel. Polymer matrix composites (PMCs) with reinforcement material as carbon nanotubes (CNTs) have shown exceptional increase in the mechanical properties. Flattened carbon nanotubes (flCNTs) are a primary component of many carbon nanotube (CNT) yarn and sheet materials, which are promising reinforcements for the next generation of ultra-strong composites for aerospace applications. These flCNT/polymer materials are subjected to extreme pressure and temperature during curing process. Therefore there is a need to investigate the evolution of properties during the curing …

Comparison Of The Thermal Stability In Equal-Channel-Angular-Pressed And High-Pressure-Torsion-Processed Fe–21cr–5al Alloy, Maalavan Arivu, Andrew Hoffman, Jiaqi Duan, Jonathan Poplawsky, Xinchang Zhang, Frank W. Liou, Rinat Islamgaliev, Ruslan Valiev, Haiming Wen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Nanostructured Steels Are Expected to Have Enhanced Irradiation Tolerance and Improved Strength. However, They Suffer from Poor Microstructural Stability at Elevated Temperatures. in This Study, Fe–21Cr–5Al–0.026C (Wt%) Kanthal D (KD) Alloy Belonging to a Class of (FeCrAl) Alloys Considered for Accident-Tolerant Fuel Cladding in Light-Water Reactors is Nanostructured using Two Severe Plastic Deformation Techniques of Equal-Channel Angular Pressing (ECAP) and High-Pressure Torsion (HPT), and their Thermal Stability between 500–700 °C is Studied and Compared. ECAP KD is Found to Be Thermally Stable Up to 500 °C, Whereas HPT KD is Unstable at 500 °C. Microstructural Characterization Reveals that ECAP KD …

Microstructure, Mechanical Properties And Oxidation Behavior Of Refractory Multi-Principal Element Alloys By Laser Remelting And Conventional Manufacturing, Visharad Jalan, Seth Crawford, Sung Heng Wu, Frank W. Liou, Haiming Wen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Refractory Multi-Principal Element Alloys (RMPEAs), HfNbTaTiZr, (HfNbTaTiZr)₉Cr, and (HfNbTaTiZr)₉Al, Were Manufactured using Vacuum Arc Melting Followed by Laser Remelting to Mimic Additive Manufacturing. the Microhardness of the As-Cast HfNbTaTiZr, (HfNbTaTiZr)₉Cr, and (HfNbTaTiZr)₉Al Samples after Arc Melting Was Measured as 6.20, 7.63, and 6.89 Gpa, respectively. after Laser Remelting and Re-Solidification, the Hardness Increased by ~ 30% for Each Composition; the Hardest Was (HfNbTaTiZr)₉Cr Measured at 9.60 GPa, While the Softest Was HfNbTaTiZr with a Hardness of 8.42 GPa, Which Was Still Harder Compared to All the Other Samples. the Addition …

Correction: Modeling Phase Selection And Extended Solubility In Rapid Solidified Alloys (Metallurgical And Materials Transactions A, (2023), 10.1007/S11661-023-07221-7), Azeez Akinbo, Yijia Gu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In the original online version of this article the reference citation in Fig. 3b was incorrect. The original article was corrected.

Preparation, Cure, And Characterization Of Cyanate Ester-Epoxy Blends Containing Reactive Flame Retardants, Mustafa Mukhtar, Donald A. Klosterman

Chemical and Materials Engineering Faculty Publications

Cyanate ester resins are sometimes mixed with lower cost epoxy monomers to modify cost, toughness, and processing capabilities. Despite the high performance of these thermosetting polymers, flame retardancy remains an issue. This study examined blends of three different commercial cyanate ester monomers (LVT-100, LECy, and XU-71787.02) and diglycidyl ether of bisphenol A (DGEBA) at 50/50 wt% of each type. The blends were successfully reacted with two reactive flame retardants (FR): 9,10-dihydro-9-ox-9-phosphaphenanthrene-10-oxide (DOPO) and poly(m-phenylene methylphosphonate) (PMP) at phosphorus contents ranging from 0 to 3 wt%. The curing behavior of EP/CE blends was investigated using differential scanning calorimetry (DSC). It was …

การเตรียมและประสิทธิภาพการเร่งปฏิกิริยาเชิงแสงของวัสดุเชิงประกอบสตรอนเชียมไททาเนตที่เจือด้วยอะลูมิเนียม/กราฟิติกคาร์บอนไนไตรด์ภายใต้แสงที่ตามองเห็น, ณัฐรุจา โตวิรัตน์กิจ

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้มีวัตถุประสงค์เพื่อเตรียมตัวเร่งปฏิกิริยาเชิงแสงของวัสดุเชิงประกอบสตรอนเชียมไททาเนตที่เจือด้วยอะลูมิเนียม/กราฟิติกคาร์บอนไนไตรด์ (Al-SrTiO3/g-C3N4) สำหรับการย่อยสลายสีย้อมโรดามีนบีและการผลิตแก๊สไฮโดรเจนจากกระบวนการแยกน้ำภายใต้การฉายแสงที่ตามองเห็น โดย SrTiO3 เตรียมด้วยวิธีปฏิกิริยาสถานะของแข็งที่อุณหภูมิ 1300 °C เป็นเวลา 12 ชั่วโมง จากนั้นนำ SrTiO3 มาเจือด้วยอะลูมิเนียม 2% โดยโมล โดยการเติมผงอะลูมินา (Al2O3) ผ่านกระบวนการฟลักซ์ด้วยการเติมเกลือสตรอนเซียมคลอไรด์ (SrCl2) ในเบ้าหลอมอะลูมินาที่อุณหภูมิ 1150 °C เป็นเวลา 10 ชั่วโมง พบว่า Al-SrTiO3 ที่ผ่านการบำบัดด้วยฟลักซ์แสดงประสิทธิภาพการย่อยสลายสีย้อมโรดามีนบีที่ดีขึ้นภายใต้แสงยูวีเมื่อเทียบกับ SrTiO3 ที่ไม่ได้ผ่านการบำบัด โดย Al-SrTiO3 ที่ผ่านการบำบัดด้วยฟลักซ์มีประสิทธิภาพการย่อยสลายสีย้อม 21.66% หลังจาก 60 นาที ซึ่งสูงกว่าประสิทธิภาพ 3.1% ของ SrTiO3 ที่สังเคราะห์โดยวิธีปฏิกิริยาสถานะของแข็งถึงเจ็ดเท่า การปรับปรุงนี้เกิดจากการบำบัดด้วยฟลักซ์ที่ช่วยเพิ่มความเป็นผลึกและส่งเสริมการแทรกตัวของ Al3+ ในโครงสร้างเพอรอฟสไกต์ของ SrTiO3 รวมถึงการสร้างตำหนิช่องว่างของออกซิเจนและลดการเกิด Ti3+ ที่เป็นอุปสรรคต่อกระบวนการเร่งปฏิกิริยาเชิงแสง จากนั้นนำ Al-SrTiO3 ที่ได้มาเตรียมวัสดุเชิงประกอบ Al-SrTiO3/g-C3N4 (5% Al-SrTiO3) ด้วยวิธีต่าง ๆ พบว่าวิธีการเผาแคลไซน์ร่วมแสดงประสิทธิภาพการย่อยสลายสีย้อมโรดามีนบีภายใต้แสงที่ตามองเห็นสูงที่สุด เมื่อเปรียบเทียบกับการเตรียมด้วยวิธีการบดผสมเชิงกล วิธีการกระจายในตัวกลาง และวิธีไฮโดรเทอร์มอล เนื่องจากวิธีการเผาแคลไซน์ร่วมทำให้ได้พื้นที่ผิวจำเพาะที่สูงขึ้น ซึ่งช่วยเพิ่มการดูดซับและการย่อยสลายสีย้อม รวมทั้งลดการรวมตัวของอิเล็กตรอนและโฮล อย่างไรก็ตามวัสดุเชิงประกอบ Al-SrTiO3/g-C3N4 ยังแสดงประสิทธิภาพการย่อยสลายสีย้อมโรดามีนบีภายใต้แสงที่ตามองเห็นต่ำกว่า g-C3N4 บริสุทธิ์เล็กน้อย ในการทดสอบประสิทธิภาพการผลิตแก๊สไฮโดรเจนของ Al-SrTiO3 ภายใต้แสงยูวีเมื่อเติมตัวเร่งปฏิกิริยาร่วมโรเดียมโครเมียมออกไซด์ (RhCrOx) 0.1% โดยน้ำหนัก พบว่า อัตราการผลิตแก๊สไฮโดรเจนเท่ากับ 568 ไมโครโมลต่อกรัมต่อชั่วโมง และเมื่อเติมไตรเอทาโนลามีน (triethanolamine, TEOA) เป็นสารเอื้อให้เกิดปฏิกิริยาเพื่อจับโฮลในแถบวาเลนซ์ อัตราการผลิตไฮโดรเจนเพิ่มขึ้นเป็น 826 ไมโครโมลต่อกรัมต่อชั่วโมง เนื่องจากอิเล็กตรอนสามารถเข้าร่วมในปฏิกิริยารีดักชันได้มากขึ้น เมื่อนำวัสดุเชิงประกอบ Al-SrTiO3/g-C3N4 ที่เตรียมด้วยวิธีการเผาแคลไซน์ร่วมที่สัดส่วนต่าง ๆ และเติมตัวเร่งปฏิกิริยาร่วม RhCrOx มาทดสอบประสิทธิภาพการผลิตแก๊สไฮโดรเจนภายใต้การฉายแสงที่ตามองเห็น ในสภาวะที่มีสารเอื้อให้เกิดปฏิกิริยา TEOA พบว่า ตัวอย่าง Al-SrTiO3/g-C3N4 …

Modification Of Natural Fibrous Materials For Sar-Cov-2 Diagnostic And Ph-Simulated Theranostic Applications, Pornchanok Punnoy

Chulalongkorn University Theses and Dissertations (Chula ETD)

This dissertation investigates the development of colorimetric sensors utilizing natural fibrous materials modified by nanomaterials to enhance the performance of chemical sensors and theranostic devices for healthcare applications. The work is divided into two main sections. The first section, cellulose is utilized as a dual-function platform for qualitative screening of SAR-CoV-2 for COVID-19 diagnosis by colorimetric sensor and quantitative detection by mass spectrometry. The cellulose is modified with gold nanoparticles conjugated to monoclonal antibodies, enabling the specific detection of viral protein antigens through colorimetric changes resulting from nanoparticle aggregation. This platform demonstrates a detection range from 0.01 to 1 µg·mL−1 …

Silver Doped Nanoceria (Agcnp) Integrated Silk Scaffold For Chronic Wound Healing, Architha K. Venkatesan

Honors Undergraduate Theses

Chronic wound healing can be seriously impeded by the formation of biofilms, infections, peri-wound edema, hematoma, osteomyelitis, and the formation of reactive oxidative species (ROS). We hypothesize that a scaffold created from Silver-Doped Nanoceria (AgCNP) embedding silk can be beneficial to aid the wound healing process, inhibit inflammation and prevent microorganisms from forming a biofilm over the wound. Current wound healing methods such as intradermal injections are not advantageous to use since they can cause unwanted responses elsewhere in the body other than the wound site. Silk, however, has a positive impact on the wound healing effect and can be …

Thermal And Electrical Properties Of Spark Plasma Sintered (Ti,Cr)B2 Ceramics, Steven M. Smith, Lun Feng, William Fahrenholtz, Gregory E. Hilmas, Laura Silvestroni

Mathematics and Statistics Faculty Research & Creative Works

Thermal and electrical properties were measured for TiB2 ceramics containing varying CrB2 contents up to 33 mol%. The room-temperature thermal diffusivity decreased with increasing Cr content from 0.330 ± 0.003 cm2/s for pure TiB2 to 0.060 ± 0.003 cm2/s for (Ti0.66Cr0.33)B2. The amount of anisotropy in the coefficients of thermal expansion increased with increasing Cr content and the c-axis had the greatest dependence on Cr addition, with an increase of more than 25% in the thermal expansion for 33 mol% CrB2 compared to TiB2, whereas the a-axis only increased by about 8%. The electrical conductivity was the lowest for (Ti0.66Cr0.33)B2 …

Cascaded Sapphire Fiber Bragg Gratings Inscribed By Femtosecond Laser For Molten Steel Studies, Dinesh Reddy Alla, Deva Prasad Neelakandan, Farhan Mumtaz, Rex E. Gerald, Laura Bartlett, Ronald J. O'Malley, Jeffrey D. Smith, Jie Huang

Electrical and Computer Engineering Faculty Research & Creative Works

This research reports a distributed fiber optic high-temperature sensing system tailored for applications in the steel industry and various other sectors. Recent advancements in optical sensor technology have led to the exploration of sapphire crystal fibers as a solution for sensing in harsh environments. Utilizing a femtosecond (fs) laser, cascaded fiber Bragg gratings (FBGs) were meticulously fabricated within a multimode sapphire optical fiber. These FBGs endowed the system with distributed sensing capabilities and underwent rigorous testing under extreme temperatures, reaching up to 1,800 °C. The study delves into the investigation of the FBG reflection spectrum, facilitated by the development of …

Predicting Compressive Strength And Hydration Products Of Calcium Aluminate Cement Using Data-Driven Approach, Sai Akshay Ponduru, Taihao Han, Jie Huang, Aditya Kumar

Electrical and Computer Engineering Faculty Research & Creative Works

Calcium aluminate cement (CAC) has been explored as a sustainable alternative to Portland cement, the most widely used type of cement. However, the hydration reaction and mechanical properties of CAC can be influenced by various factors such as water content, Li₂CO₃ content, and age. Due to the complex interactions between the precursors in CAC, traditional analytical models have struggled to predict CAC binders' compressive strength and porosity accurately. To overcome this limitation, this study utilizes machine learning (ML) to predict the properties of CAC. The study begins by using thermodynamic simulations to determine the phase assemblages of …

Drop Wetting And Sliding On Soft, Swollen Elastomers, Zhuoyun Cai

Theses and Dissertations--Chemical and Materials Engineering

Soft, slippery surfaces have gained increasing attention due to their wide range of potential applications, for example in self-cleaning, anti-fouling, liquid collection, and more. One design approach in creating slippery surfaces is using a swollen elastomer, which is a polymer network swollen with a lubricant. This type of surface may be beneficial for longer-term use than standard lubricant-infused surfaces, and provides a versatile surface with tunable mechanical properties. Hence, understanding the physics of soft surface interactions is important for fundamental soft matter physics, biomaterials, adhesives, and coatings. This research experimentally investigates wetting on soft infused networks, with the aim of …

Effects Of Confinement On Ionic Liquids And Deep Eutectic Solvents For The Design Of Catalytic Systems, Electrochemical Devices, And Separations, Andrew Drake

Theses and Dissertations--Chemical and Materials Engineering

Confinement of ionic liquids (ILs) and deep eutectic solvents (DESs) within mesoporous materials such as silica helps to control the local environment within the pores for applications such as catalysis, electrochemistry, and absorption. Silica thin films with 2.5 and 8 nm pores and micron-sized silica particles with pore diameters of 5.4 and 9 nm were synthesized to study the effect of nanoconfinement on ILs 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF₆]), 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]), and DESs reline and ethaline (choline chloride and urea or ethylene glycol). Silica thin films with vertically aligned, well ordered, and accessible pores were synthesized via the evaporation-induced …

Development Of Interatomic Potential Of High Entropy Diborides With Artificial Intelligence Approach To Simulate The Thermo-Mechanical Properties, Nur Aziz Octoviawan

Graduate Theses/Dissertations

The interatomic potentials designed for binary/high entropy diborides and ultra-high temperature composites (UHTC) have been developed through the implementation of deep neural network (DNN) algorithms. These algorithms employed two different approaches and corresponding codes; 1) strictly local & invariant scalar-based descriptors as implemented in the DEEPMD code and 2) equivariant tensor-based descriptors as included in the ALLEGRO code. The samples for training and validation sets of the forces, energy, and virial data were obtained from the ab-initio molecular dynamics (AIMD) simulations and Density Functional Theory (DFT) calculations, including the simulation data from the ultra-high temperature region (> 2000K). The study …

Defect State Study And Surface Patching In Zno Nanoparticles Via Nano- Bio Interaction With Dna Bases, Ummay Honey

Graduate Theses/Dissertations

First, this thesis investigates the structural and optical properties of hydrothermally synthesized ZnO nanostructures, focusing on the effects of varying annealing temperatures on their properties. Structural characterizations using micro-Raman spectroscopy, X-ray diffraction (XRD), and morphological study called scanning electronic microscopy (SEM) show changes in crystallinity and intensity with different annealing temperatures. Optoelectronic characterization using photoluminescence spectroscopy reveals changes in luminescence properties near the ultraviolet region with temperature variation and in the visible emission area region. These results provide insights into how annealing temperature can affect the surface layer of ZnO nanostructures and can be applied to improve performance in electronic …

A Study Of Synthesis And Characterization Of Naxmno2-Δ As A Cathode Material For Sodium-Ion Battery, Zia Uddin Mahmud

Graduate Theses/Dissertations

The proliferation of renewable energy sources and the promising market for net-scale battery applications immediately increases the need for electrochemical energy storage technology. Sodium (Na) components are more accessible and less expensive than lithium. Being a sodium-based material with a high-power density provided by Na-ion diffusion, Na_xMnO_{2- δ} is a strong contender for large-scale Sodium-ion-battery (SIB) applications. In the current study, Na_xMnO_{2- δ} is created using a solid-state reaction technique, and investigated structural, electrical, and electrochemical properties of materials were investigated using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), UV-VIS spectroscopy, and …

Synthesis, Characterization, And Application Of Chitosan Nanoparticles For In Vitro Studies On Hela Cancer Cells, Rejeena Jha

Graduate Theses/Dissertations

Chitosan is a fibrous substance that is derived from chitin, a natural substance in the shells of crustaceans. It possesses all the necessary qualities for being used as carrier for the transport of drugs and genes into tumor, such as biodegradability, biocompatibility, hydrophilicity, and non-toxicity and cationic in nature. Ionic gelation method was used to synthesize chitosan (CS) nanoparticles (NPs). Ionic gelation is a very benign process chemically that requires mixing a CS aqueous solution with a sodium tripolyphosphate (TPP) aqueous solution at room temperature. In addition, a surfactant polyethylene oxide (PEO) alone and a diblock copolymer of PEO and …

Exploration And Synthesis Of Half-Heusler And Disordered Ternary Intermetallic Single Crystals, Md Fahel Bin Noor

Graduate Theses/Dissertations

Due to their distinct physical and chemical characteristics, half-Heusler compounds are intermetallic materials that have undergone substantial research. The general formula for these compounds is XYZ, where X and Y are transition metals and Z is a p-block element. Thermoelectricity is among the half-Heusler compounds' most exciting potential uses, but additional possible applications include spintronics, magnetic refrigeration, and superconductivity, among others. Recently, half-Heuslers (and Heuslers) have emerged as candidates for catalysts for hydrogenation. The CoNbSn half-Heusler compound, as well as another unique intermetallic ternary compound, the disordered Mn_4-xCr_xAl₁₁, were successfully grown as single crystals …

Synthesis And Characterization Of Cage-Structured Compounds As Promising Thermoelectric Materials, Nusrat Yasmin

Graduate Theses/Dissertations

The development of new thermoelectric materials is of great interest due to their potential to convert waste heat into useful electricity. The primary problem is that the physical factors that are utilized to assess thermoelectric performance conflict with one another. One way to improve their performance is to hinder the lattice from conducting heat through its vibrations while maintaining the heat conduction via the electrons. This can be done by creating cage structures that allow heavy atoms to jiggle. In this study, we report the synthesis of a group of such compounds, using the self-flux method. They all belong to …

Classifying Sidewalk Materials Using Multi-Modal Data, Jiawei Liu

Dissertations and Theses

Navigating safely and independently presents considerable challenges for people who are blind or have low vision (BLV), as it requires a comprehensive understanding of their neighborhood environment. Our user study reveals that materials and objects on sidewalks play a crucial role in navigation tasks. Unfortunately, current methods for assessing sidewalk materials are suboptimal, often relying on labor-intensive and expensive manual assessments that fail to capture the full range of sidewalk features critical to individuals with BLV.

In response to this problem, this master’s thesis investigates deep learning approaches specifically designed for the classification of multi-modal sidewalk materials. The proposed framework …

Mechanical Design Of A Microwave Imaging Device For Breast Cancer Detection In Mri Scanners, Grace M. Player

Dartmouth College Master’s Theses

This project seeks to develop an updated version of a microwave imaging device for use in conjunction with breast MRI, improving upon existing technology and developing novel concepts for the device. It posits three primary redesign targets for updating the previous system: resizing the system height, making the device more iteration- friendly, and improving the overall manufacturability of the device by replacing custom components with commercially available alternatives. All three of these redesign targets are met in the new design, V2.0. The height is reduced by reducing antenna travel and height, embedding some components, and shortening the tank wall, resulting …

Characterization Of Virgin, Re-Used, And Oxygen-Reduced Copper Powders Processed By The Plasma Spheroidization Process, M. Hossein Sehhat, David Perez-Palomino, Connor Wiedemeier, Tristan Cullom, Joseph William Newkirk

Mathematics and Statistics Faculty Research & Creative Works

Fabrication of parts with high mechanical properties heavily depend on the quality of powder deployed in the fabrication process. Copper powder in three different powder types were spheroidized using radio-frequency inductively coupled plasma (ICP) spheroidization process (TekSphero-15 system). The characterized powders include virgin powder as purchased from the powder manufacturer, powder used in electron beam powder bed fusion (EB-PBF) process, and reconditioned powder, which was used powder that underwent an oxygen-reduction treatment. The goal of spheroidizing these powder types was to evaluate the change in powder morphology, the possibility of enhancing the powder properties back to their as-received conditions, and …

Predicting Dissolution Kinetics Of Tricalcium Silicate Using Deep Learning And Analytical Models, Taihao Han, Sai Akshay Ponduru, Arianit Reka, Jie Huang, Gaurav Sant, Aditya Kumar

Electrical and Computer Engineering Faculty Research & Creative Works

The dissolution kinetics of Portland cement is a critical factor in controlling the hydration reaction and improving the performance of concrete. Tricalcium silicate (C₃S), the primary phase in Portland cement, is known to have complex dissolution mechanisms that involve multiple reactions and changes to particle surfaces. As a result, current analytical models are unable to accurately predict the dissolution kinetics of C₃S in various solvents when it is undersaturated with respect to the solvent. This paper employs the deep forest (DF) model to predict the dissolution rate of C₃S in the undersaturated solvent. The …

High Figure Of Merit Spin Polarized Electron Sources Grown Via Mocvd, Benjamin Belfore, Adam Masters, Deewakar Poudel, Greg Blume, Stephen Polly, Erdong Wang, Seth M. Hubbard, Marcy Stutzman, Joseph M. Grames, Matt Poelker, Matt Grau, Sylvain Marsillac

Electrical & Computer Engineering Faculty Publications

Spin polarized photocathodes are key to the future operation of electron accelerators such as the ones at Thomas Jefferson National Accelerator Facility and Brookhaven National Laboratory. Currently, these photocathodes come in short supply due to limited production by molecular beam epitaxy. By developing a process to implement similar structures using metal organic chemical vapor deposition, the availability of these devices can be increased. In this paper, we detail the implementation of recent photocathode advancements via metal organic chemical vapor deposition process and show an improvement in both polarization and quantum efficiency of our devices compared to those fabricated via molecular …

Hydrogen-Wettability Alteration Of Indiana Limestone In The Presence Of Organic Acids And Nanofluid, Mirhasan Hosseini, Rossen Sedev, Mujahid Ali, Muhammad Ali, Jalal Fahimpour, Alireza Keshavarz, Sefan Iglauer

Research outputs 2022 to 2026

This study focuses on the wettability alteration (changing from a hydrophobic state to a hydrophilic state) of Indiana limestone for hydrogen (H₂) geological storage. We examine the effect of hexanoic acid C₆, lauric acid C₁₂, and stearic acid C₁₈, on the wettability of Indiana limestone at ambient (298 K and 0.1 MPa) and reservoir (323 K and 8.27 MPa) conditions. The effects of silica nanofluids (silica with deionized water) at various concentrations (0.1 wt%, 0.25 wt%, and 0.5 wt%) on the wettability reversal of stearic-aged samples were tested at ambient and reservoir …

Crosslinking Enhancement Of Natural Rubber By Electron Beam, Mili Purbaya

Chulalongkorn University Theses and Dissertations (Chula ETD)

Vulcanization is a crucial process that transforms raw rubber into a durable and useful material. During vulcanization, crosslinking points are created between rubber molecules, which convert them into a thermosetting substance. The conventional vulcanization method is carried out by the addition of some chemicals accompanied by the application of thermal energy. This study explored the possibility of using electron beam irradiation which is an environmentally friendly and short-time method for vulcanizing natural rubber. The research was divided into two parts. In the first part, the efficacy of electron beam vulcanization was compared to that of thermal vulcanization. Natural rubber containing …

Cellulose Nanofiber/Poly(Acrylic Acid)-Based Hydrogel For Colorimetric Biomarker Sensors, Nichaphat Passornraprasit

Chulalongkorn University Theses and Dissertations (Chula ETD)

This dissertation develops innovative CNF/PAA hydrogel-based colorimetric sensors for non-invasive biomarker detection, focusing on urea for chronic kidney disease (CKD) and sarcosine for prostate cancer (PCa). Hydrogels serve as a matrix for enzyme and indicator encapsulation due to their high absorption capacity and unique three-dimensional network, with CNF enhancing mechanical properties. The research is divided into two parts. Part I involves preparing a GO/CNF/PAA hydrogel via non-toxic radiation crosslinking, featuring high swelling capacity and enhanced laser absorptivity due to GO. This hydrogel, used as a patch for on-skin detection, shows vivid color changes to distinguish CKD patients from healthy individuals, …

Higher-Order Effects In Biaxial Flexure Of Gfrp I-Section Beams, Zia Razzaq, Faridoon Z. Razzaq

Civil & Environmental Engineering Faculty Publications

A theoretical study of Glass Fiber Reinforced Polymer (GFRP) beams subjected to biaxial bending moments is presented with a focus on the influence of higher-order effects on maximum normal stresses. It is shown that the biaxial bending type of loading causes a dramatic increase in the maximum normal stress for a GFRP beam when induced torsional effects are included. The study demonstrates that the traditional first-order theory can grossly underestimate the maximum normal stress in a GFRP beam. Based on the numerical results presented using a higher-order theory which also accounts for induced warping normal stresses, the maximum normal stress …