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Articles 1411 - 1440 of 14237

Full-Text Articles in Chemical Engineering

Machine Learning Approaches To The Exploration Of Ammonia Synthesis Catalysts Utilizing Experimental Data, Rasika Jayarathna Jul 2024

Machine Learning Approaches To The Exploration Of Ammonia Synthesis Catalysts Utilizing Experimental Data, Rasika Jayarathna

Theses and Dissertations

Traditional heterogeneous catalyst discovery process relies upon human expert-guided experiments based on domain knowledge and human intuition supported by catalyst characterization. However, this process is time and resource-consuming and suffers from human bias. Machine learning (ML) models trained on experimental data have the potential to significantly accelerate this discovery process by guiding experiments to optimize the catalyst performance and increase the understanding of the catalysts. Ammonia synthesis catalysts are a class of catalysts widely investigated in the literature, which has generated decades of experimental data. Moreover, ammonia has been gaining attention since it can be used as a carbon-free next-generation …


Applications Of Catalytic Ammonia Chemistry: From Low-Pressure Ammonia Synthesis To The Decomposition Of Tritiated Ammonia As A By-Product Of Magnetically Confined Nuclear Fusion, Jennifer Kules Naglic Jul 2024

Applications Of Catalytic Ammonia Chemistry: From Low-Pressure Ammonia Synthesis To The Decomposition Of Tritiated Ammonia As A By-Product Of Magnetically Confined Nuclear Fusion, Jennifer Kules Naglic

Theses and Dissertations

Ammonia is the 2nd most produced chemical in the world with vital importance for its use in fertilizer as the global population has grown in accordance with the industrialization of NH3. While 80% of NH3 produced goes to fertilizer, it has gained attention recently as a hydrogen storage and transportation vessel. Industrially, NH3 is produced at high temperatures and pressures which in turn require high electrical input. Turning to a green NH3 cycle with low temperature and pressure membrane reactors for both NH3 synthesis and decomposition would allow for much lower energy input as well as a renewable energy to …


Dynamic Metabolic Flux Analysis Amidst Data Variability: Sphingolipid Biosynthesis Case Study In Arabidopsis Thaliana Cell Cultures, Abraham Boluwatife Osinuga Jul 2024

Dynamic Metabolic Flux Analysis Amidst Data Variability: Sphingolipid Biosynthesis Case Study In Arabidopsis Thaliana Cell Cultures, Abraham Boluwatife Osinuga

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

Sphingolipids are pivotal for plant development and stress responses. Growing interest has been directed towards fully comprehending the regulatory mechanisms of the sphingolipid pathway. In this study, we explore its de novo biosynthesis and homeostasis in Arabidopsis thaliana cell cultures, shedding light on fundamental metabolic mechanisms. Employing 15N isotope labeling and quantitative dynamic modeling approach, we obtained data with notable variations and developed a regularized and constraint-based Dynamic Metabolic Flux Analysis (r-DMFA) framework to predict metabolic shifts due to enzymatic changes. Our analysis revealed key enzymes such as sphingoid-base hydroxylase (SBH) and long-chain-base kinase …


Characteristics Of Pyrolysis Products Of California Chaparral And Their Potential Effect On Wildland Fires, Mahsa Alizadeh, David R. Weise, Thomas H. Fletcher Jul 2024

Characteristics Of Pyrolysis Products Of California Chaparral And Their Potential Effect On Wildland Fires, Mahsa Alizadeh, David R. Weise, Thomas H. Fletcher

Faculty Publications

The aim of this study was to investigate the pyrolysis of selected California foliage and estimate the energy content of the released volatiles to show the significance of the pyrolysis of foliage and its role during wildland fires. While the majority of the volatiles released during the pyrolysis of foliage later combust and promote fire propagation, studies on the energy released from combustion of these compounds are scarce. Samples of chamise (Adenostoma fasciculatum), Eastwood’s manzanita (Arctostaphylos glandulosa), scrub oak (Quercus berberidifolia), hoaryleaf ceanothus (Ceanothus crassifolius), all native to southern California, and sparkleberry …


Carbon-Based Nanocomposite Membranes For Membrane Distillation: Progress, Problems And Future Prospects, Chhabilal Regmi, Yuwaraj K. Kshetri, S. Ranil Wickramasinghe Jul 2024

Carbon-Based Nanocomposite Membranes For Membrane Distillation: Progress, Problems And Future Prospects, Chhabilal Regmi, Yuwaraj K. Kshetri, S. Ranil Wickramasinghe

Chemical Engineering Faculty Publications and Presentations

The development of an ideal membrane for membrane distillation (MD) is of the utmost importance. Enhancing the efficiency of MD by adding nanoparticles to or onto a membrane’s surface has drawn considerable attention from the scientific community. It is crucial to thoroughly examine state-of-the-art nanomaterials-enabled MD membranes with desirable properties, as they greatly enhance the efficiency and reliability of the MD process. This, in turn, opens up opportunities for achieving a sustainable water–energy–environment nexus. By introducing carbon-based nanomaterials into the membrane’s structure, the membrane gains excellent separation abilities, resistance to various feed waters, and a longer lifespan. Additionally, the use …


Impact Of Non-Thermal Plasma Generated Using Air And Nitrogen On Functional Properties Of Milk Protein Dispersions, Nikitha Modupalli, Md Mahfuzur Rahman Jul 2024

Impact Of Non-Thermal Plasma Generated Using Air And Nitrogen On Functional Properties Of Milk Protein Dispersions, Nikitha Modupalli, Md Mahfuzur Rahman

Food Science Faculty Publications and Presentations

This study focuses on improving the functionalities of milk protein concentrate (MPC) using a nonthermal plasma jet and plasma-activated water (PAW) with atmospheric air and nitrogen as source gases. The 5% and 10% MPC dispersions were directly treated with a plasma jet, and PAW was used to make the MPC dispersions. The dispersions were analyzed for changes in protein structure and functional properties. The treatment altered the secondary structure of MPC protein structure by increasing β-components and changing the order of random coils. The solubility of the PAW-treated 5% protein dispersions doubled due to plasma-induced modification of hydrophilic and covalent …


Rock Structural Changes Monitored By Fibre Bragg Grating Sensors And Nuclear Magnetic Resonance During Static And Dynamic Carbonated Brine Core Flooding Experiments, Bruno Da Silva Falcão, Lionel Esteban, Ausama Giwelli, Ahmed Al-Yaseri, Alireza Keshavarz, Jeremie Dautriat, Stephanie Vialle, Stefan Iglauer Jul 2024

Rock Structural Changes Monitored By Fibre Bragg Grating Sensors And Nuclear Magnetic Resonance During Static And Dynamic Carbonated Brine Core Flooding Experiments, Bruno Da Silva Falcão, Lionel Esteban, Ausama Giwelli, Ahmed Al-Yaseri, Alireza Keshavarz, Jeremie Dautriat, Stephanie Vialle, Stefan Iglauer

Research outputs 2022 to 2026

One proposed solution to reduce greenhouse gas emissions is the capture and storage of carbon dioxide (CCS) in geological formations such as depleted oil and gas reservoirs. Injected carbon dioxide (CO2) forms carbonic acid once dissolved in the formation water, which can lead to dissolution of certain types of rock minerals. This may weaken rock geomechanical properties that can jeopardize the safety of long-term storage. In this work, the use of Fibre Bragg Grating (FBG) sensors associated with Nuclear Magnetic Resonance (NMR) was investigated to measure the change in rock strain during core flooding experiments. Optical fibres were glued onto …


Resilient Forward Osmosis Membranes Against Microplastics Fouling Enhanced By Mwcnts/Uio-66-Nh2 Hybrid Nanoparticles, Mitra Golgoli, Javad Farahbakhsh, Mohadeseh Najafi, Mehdi Khiadani, Michael L. Johns, Masoumeh Zargar Jul 2024

Resilient Forward Osmosis Membranes Against Microplastics Fouling Enhanced By Mwcnts/Uio-66-Nh2 Hybrid Nanoparticles, Mitra Golgoli, Javad Farahbakhsh, Mohadeseh Najafi, Mehdi Khiadani, Michael L. Johns, Masoumeh Zargar

Research outputs 2022 to 2026

The escalating presence of microplastics (MPs) in wastewater necessitates the investigation of effective tertiary treatment process. Forward osmosis (FO) emerges as an effective non-pressurized membrane process, however, for the effective implementation of FO systems, the development of fouling-resistance FO membranes with high-performance is essential. This study focuses on the integration of MWCNT/UiO-66-NH2 as metal-organic frameworks (MOFs) and multi-wall carbon nanotubes (MWCNT) nanocomposites in thin film composite (TFC) FO membranes, harnessing the synergistic power of hybrid nanoparticles in FO membranes. The results showed that the addition of MWCNT/UiO-66-NH2 in the aqueous phase during polyamide formation changed the polyamide surface structure, and …


High–Strength Porous Tinbzrtafe Alloys Fabricated By Sintering Of Nanocomposite Powder Precursor With Space Holder Technique, Yuhua Li, Yuxin He, Rong Zhao, Libin Niu, Juxin Qu, Lai Chang Zhang Jul 2024

High–Strength Porous Tinbzrtafe Alloys Fabricated By Sintering Of Nanocomposite Powder Precursor With Space Holder Technique, Yuhua Li, Yuxin He, Rong Zhao, Libin Niu, Juxin Qu, Lai Chang Zhang

Research outputs 2022 to 2026

Although introducing high porosity in biomedical Ti alloys can reduce their elastic modulus and promote new bone ingrowth, relieving the stress–shielding effect and implant failure, this also causes a decline in the alloys’ mechanical strength. In this work, a new preparation method for the high–strength and high–porosity Ti65Nb23.33Zr5Ta1.67Fe5 (TNZTF, at.%) alloy was suggested by sintering nanocomposite powder precursor in combination with the use of a space holder technique, in which NH4HCO3 is adopted to achieve a porous structure. The highly porous TNZTF alloy possesses a homogeneous fine–grained microstructure consisting of equiaxed α–Ti and a small amount of FeTi2, the latter …


Preparation, Reaction Mechanism And Microwave-Absorbing Application Of Functional Transition Metal Carbide/Nitride Ceramic Materials, Zhengbo Xu, Shu Qing Kou, Bai Xin Dong, Xinmiao Zhong, Hongyu Yang, Lin Liu, Ruifen Guo, Shi Li Shu, Feng Qiu, Lai Chang Zhang Jul 2024

Preparation, Reaction Mechanism And Microwave-Absorbing Application Of Functional Transition Metal Carbide/Nitride Ceramic Materials, Zhengbo Xu, Shu Qing Kou, Bai Xin Dong, Xinmiao Zhong, Hongyu Yang, Lin Liu, Ruifen Guo, Shi Li Shu, Feng Qiu, Lai Chang Zhang

Research outputs 2022 to 2026

The explosive growth of wireless communications and electronic devices has brought electromagnetic radiation's harmfulness and hidden trouble to light, which has a major impact on electrical equipment's ability to function normally. MXene, a material with favorable features like conductivity, a unique two-dimensional multiple-layer structure and abundant surface functional groups, has made it a viable contender for high-performance microwave-absorbers. This article introduces the synthesis strategy of MXene/MXene-based materials and their parent phase MAX, comprehensively summarizes and analyzes the current progress in the study on the microwave-absorbing properties of MXene/MXene-based materials, analyzes the main problems and bottlenecks. Future research directions for MXene …


Preparation Of Β-Ni (Oh)2 Nanosheet–Modified Glassy Carbon For Pseudocapacitors, Muhammad Buchari Setia Putra, Aliyah Aliyah, Afiten Rahmin Sanjaya, Respati Kevin Pramadewandaru, Hoeil Chung, Tribidasari Anggraningrum Ivandini Jun 2024

Preparation Of Β-Ni (Oh)2 Nanosheet–Modified Glassy Carbon For Pseudocapacitors, Muhammad Buchari Setia Putra, Aliyah Aliyah, Afiten Rahmin Sanjaya, Respati Kevin Pramadewandaru, Hoeil Chung, Tribidasari Anggraningrum Ivandini

Makara Journal of Science

β-Nickel hydroxide (Ni(OH)2) nanosheet–modified glassy carbon for pseudocapacitors was successfully prepared. The nanosheets were synthesized via a conventional growth seeding method combined with hydrothermal treatment. Transmission electron microscopy (TEM) characterization indicated the hexagonal structure of the nanosheets of around 15 nm in size, and X-ray diffraction (XRD) pattern confirmed the β-phase lattice crystal. These nanosheets used to modify the glassy carbon surface, increased the electroactive surface area by around 15 times. Furthermore, electrochemical investigation of the modified glassy carbon revealed an excellent performance and a specific capacitance of 628.01 F g−1 at a 1 A g−1 …


Optimizing The Expression Of Polyethylene Terephtalate Hydrolase-Encoding Synthetic Gene In Escherichia Coli Arctic Express (De3), Jocelyn Nataniel, Maria Ulfah, Dini Achnafani, Niknik Nurhayati, Gabriela Christy Sabbathini, Sri Rezeki Wulandari, Abinawanto Abinawanto, Is Helianti Jun 2024

Optimizing The Expression Of Polyethylene Terephtalate Hydrolase-Encoding Synthetic Gene In Escherichia Coli Arctic Express (De3), Jocelyn Nataniel, Maria Ulfah, Dini Achnafani, Niknik Nurhayati, Gabriela Christy Sabbathini, Sri Rezeki Wulandari, Abinawanto Abinawanto, Is Helianti

Makara Journal of Science

The waste of polyethylene terephthalate (PET) plastic waste in Indonesia is a pressing concern due to its slow degradation and potential environmental damage. One promising solution is to utilize polyethylene terephthalate hydrolase from Ideonella sakaiensis (IsPETase), an enzyme that specifically degrades PET. However, inducing the expression of IsPETase synthetic gene in Escherichia coli BL21 (DE3) has been challenging because much of it remains insoluble. This study aimed to express IsPETase in E. coli Arctic Express (DE3) and optimize the conditions to enhance its production. First, pET22b(+)pelB-IsPETase was inserted into E. coli Arctic Express (DE3). The …


Algorithms And Models For Synthesis Of Elements Of Digital Information Systems, Odil Abdujalilovich Jumaev, M.T. Ismoilov, V.B. Pulatov, G.X. Rashidov Jun 2024

Algorithms And Models For Synthesis Of Elements Of Digital Information Systems, Odil Abdujalilovich Jumaev, M.T. Ismoilov, V.B. Pulatov, G.X. Rashidov

Chemical Technology, Control and Management

The development of algorithms for noise-tolerant and high-speed measurement systems involves an integrated approach that encompasses methods of data processing and transmission, as well as mechanisms for rapid response to changes. This paper presents the key principles and techniques used in such technologies. The information systems are thoroughly analyzed, including the use of signal processing techniques and their identification, filtering using various statistical techniques to determine signal parameters and the development of algorithms to analyze and classify signals. Critical aspects of the system such as performance, reliability, security and scalability are also evaluated. The paper discusses information system structures and …


Ultrasonic Flow Meter Calibration Via The Internet Using An Analog-To-Digital Converter, Aliev Ravshan, A.U. Djalilov Jun 2024

Ultrasonic Flow Meter Calibration Via The Internet Using An Analog-To-Digital Converter, Aliev Ravshan, A.U. Djalilov

Chemical Technology, Control and Management

The purpose of scientific research work is remote control of improving the metrological properties of the water flow measuring device. Therefore, the Arduino platform with an additional ESP8266 NodeMcu v3 and analog-to-digital converter, module was installed in the scientific article for automatic calibration/checking of ultrasonic flow meters used in irrigation networks. The module is integrated into a 32-bit microcontroller with low power consumption. The ESP8266 NodeMcu v3 module operates at 80 and 160 MHz clock frequencies, supports real-time operating system (RTOS), built-in Wi-Fi, and has a microstrip antenna on board. Through this, the data exchange between the computing equipment and …


Research Of The Fuzzy Control System For Adjusting Thread Tension During The Warping Process, To'xtamurod Hayitmurodovich Avezov, Zokhid Ergashboyevich Iskandarov Jun 2024

Research Of The Fuzzy Control System For Adjusting Thread Tension During The Warping Process, To'xtamurod Hayitmurodovich Avezov, Zokhid Ergashboyevich Iskandarov

Chemical Technology, Control and Management

The paper considered issues of research into a fuzzy control system for the warping process. During the warping process, the reasons that cause defects in the final finished product have been studied, firstly (remove this word) which are thread breakage, thread tangling, the formation of loops on or under the belt, hanging loose threads and similar factors. To study the warping process, its mathematical model is constructed. Kinematic parameters of stationary movement corresponding to the equilibrium mode were determined by solving the nonlinear functional matrix - equation of movement. The process of breakage the warp of the threads under oscillation …


Research Of A New Technological Flowsheet Parameters For Uranium Mining From Technogenic Uranium Ores, Nazarov Jamol, G.M. Allaberganova, H.L. Pulatov, A.M. Muzafarov Jun 2024

Research Of A New Technological Flowsheet Parameters For Uranium Mining From Technogenic Uranium Ores, Nazarov Jamol, G.M. Allaberganova, H.L. Pulatov, A.M. Muzafarov

Chemical Technology, Control and Management

This paper presents the results of a study of the parameters of a new technological scheme for the extraction of uranium from technogenic uranium ores. The results of the analytical determination of the concentration of parent - 238U and daughter radionuclides - 234U , 230Th , 226Ra , 222Rn , 218Pa , 214Pb , etc. are presented . in the studied technogenic uranium ores. The principal scheme of the new uranium extraction technology from technogenic uranium ores is presented. The use of the classifier in a new scheme for separating granules of technogenic …


Assessment Of Metrological Errors Of Recognition Metrics In The Intelligent Control And Regulation System Of The Cotton Harvesting Machine, Erkin Uljaev, Utkirjon Murodillaevich Ubaydullaev, Azizjon Abdulla Ugli Abdulhamidov Jun 2024

Assessment Of Metrological Errors Of Recognition Metrics In The Intelligent Control And Regulation System Of The Cotton Harvesting Machine, Erkin Uljaev, Utkirjon Murodillaevich Ubaydullaev, Azizjon Abdulla Ugli Abdulhamidov

Chemical Technology, Control and Management

This article presents a method for assessing the error of metrics of an intelligent system for monitoring and regulating the width of the working gap of the harvesting apparatus of a cotton picker. To assess the error, the calculation of the average value of the standard deviation of metrics, absolute systematic and random errors, as well as absolute and relative total errors are used. The results of these calculations will allow us to determine the accuracy of the recognition system and opportunities for its improvement.


Environmental Monitoring And Control System Of Greenhouse Based On Internet Of Things Technology, Ru Jiang, Nadirbek Yusupbekov Jun 2024

Environmental Monitoring And Control System Of Greenhouse Based On Internet Of Things Technology, Ru Jiang, Nadirbek Yusupbekov

Chemical Technology, Control and Management

Greenhouse is an important application scene of modern agriculture. In this paper, a set of greenhouse environmental monitoring, facility remote control and production management system is designed and implemented based on Internet of Things technology for the development needs of modern agriculture in greenhouse. The system selects STM32F407 control board as the main controller to realize real-time monitoring of greenhouse environmental parameters including temperature and humidity, soil nutrients, soil pH and other greenhouse environmental information, and can adjust greenhouse environmental parameters by controlling the irrigation system, roller shutters, fans, shading curtains and other facilities in the greenhouse. The main controller …


Structural And Parametric Identification Of Recycling Systems, Khusan Igamberdiev, Madina Mirxalilovma Fozilova Jun 2024

Structural And Parametric Identification Of Recycling Systems, Khusan Igamberdiev, Madina Mirxalilovma Fozilova

Chemical Technology, Control and Management

The issue of identifying recirculation systems with a specific control loop, in which information and control information about various technological processes circulate, is being considered. A methodology for identifying recirculation systems has been developed, based on algorithms for structural identification of the model based on the results of assessing the sensitivity of the optimum of control parameters and a fuzzy inference algorithm based on production rules that contribute to solving the problem of parametric identification.


Synthesis Of An Adaptive Neuro-Fuzzy Control System For Steam Generator Temperature, Isomiddin Xakimovich Siddikov, Dilnoza Maxamadjanovna Umurzakova Jun 2024

Synthesis Of An Adaptive Neuro-Fuzzy Control System For Steam Generator Temperature, Isomiddin Xakimovich Siddikov, Dilnoza Maxamadjanovna Umurzakova

Chemical Technology, Control and Management

This paper is devoted to the modeling and synthesis of an adaptive neuro-fuzzy control system for steam generator temperature. Temperature control systems play an important role in industry because accurate and stable control is a prerequisite for the efficient operation of steam systems. Traditional control methods based on mathematical models and fixed parameter controllers may have limitations in providing optimal performance and adapting to changing operating conditions. The paper proposes a synthesized system combining fuzzy logic and adaptation methods to achieve more accurate and stable temperature control. A detailed structural diagram of the system, modeling, and tuning methods are presented. …


Decision-Making Algorithms For Drilling Instrument Control Systems, Fuzayl Fozil Ugli Odilov Jun 2024

Decision-Making Algorithms For Drilling Instrument Control Systems, Fuzayl Fozil Ugli Odilov

Chemical Technology, Control and Management

The control of the movement of the drilling tool and the structure of the well are considered. An effective control algorithm for drilling systems that provides control of well trajectory parameters is analyzed. In technological processes, it is necessary to control several parameters or several systems at the same time. It is considered necessary to create decision-making algorithms for the formation of managerial effects for the control system of such technological processes. The controlled oriented type of the bottom of the drill string was analyzed. Work was carried out on the decision-making algorithm for the processing of control effects. The …


Manufacturing Of Aligned Electrospun Nanofiber Yarns For Their Enhanced Mechanical And Piezoelectric Properties, Adaugo Mary-Frances Enuka Jun 2024

Manufacturing Of Aligned Electrospun Nanofiber Yarns For Their Enhanced Mechanical And Piezoelectric Properties, Adaugo Mary-Frances Enuka

Theses and Dissertations

Electrospinning is a widely used technique for producing nanofibers with diverse applications. This method uses polymer solutions and strong electric fields to generate nano-sized fibers with unique properties. This study presents a novel manufacturing approach that enables the production of electrospun poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanofiber yarns using an automated parallel track system and an adjustable roll-to-roll collector. This research examines the impact of an automated post-drawing system on the polymer chain orientation, crystallinity, tensile strength, morphology, and piezoelectric properties of PVDF-HFP nanofiber yarn. The results reveal that the post-drawing process significantly improves molecular alignment, increases tensile strength, and enhances the …


Tuning Polymer Glass Formation Behavior And Understanding Time-Temperature Superposition Breakdown With Oligomeric Additives, Peijing Yue Jun 2024

Tuning Polymer Glass Formation Behavior And Understanding Time-Temperature Superposition Breakdown With Oligomeric Additives, Peijing Yue

USF Tampa Graduate Theses and Dissertations

The glass transition of polymer melts has been investigated for over a century. Even so, there are still many unanswered questions about the underlying physics. Countless theories were proposed to explain and define glass transition temperatures. More specifically, both the origins of the glass transition and underlying classification of glass as a state of matter remain unresolved. Time-temperature superposition (TTS) is one of the most widely used techniques to characterize the viscoelastic behavior of a material and the mechanical behavior and is employed to reduce the measuring time during characterization. Despite the widespread use of TTS, many authors have reported …


Investigating The Feasibility And Mechanisms Of Cold Spray Deposition Of Polymer-Based Powders On Fiber-Reinforced Composite Substrates, Nicholas Beau Mennie Jun 2024

Investigating The Feasibility And Mechanisms Of Cold Spray Deposition Of Polymer-Based Powders On Fiber-Reinforced Composite Substrates, Nicholas Beau Mennie

Theses and Dissertations

Fiber-reinforced composites have become important structural components in industries such as aerospace and energy due to their high mechanical strength and relatively light structural weight. However, during operation, these materials can be prone to impact damage and disintegration. Effective protection via metalization and repair of composites would, therefore, reduce the cost and time for replacement parts. Polymer-based cold spray, while a relatively new technique, can be utilized to metalize and possibly repair composite materials subjected to impact-induced damage. In this work, studies involving polymers and composite cold spray were performed to enable the process of safeguarding, enhancing, or repairing various …


Copper-Based Electrocatalysts For Electrochemical Reduction Of Co2 To C2 Products, Monsuru Olatunji Dauda Jun 2024

Copper-Based Electrocatalysts For Electrochemical Reduction Of Co2 To C2 Products, Monsuru Olatunji Dauda

LSU Master's Theses

The electrochemical reduction of CO2 using copper-based electrocatalysts has emerged as a promising approach for sustainable chemical production, offering a pathway to mitigate the rising atmospheric CO2 levels while generating valuable fuels and chemicals. However, the selectivity and efficiency of copper-based catalysts towards specific C2 products remain a major challenge, hindering their commercial viability. This thesis focuses on the development, characterization, and mechanistic understanding of three promising electrocatalyst systems for multi-carbon product generation from CO2 reduction: copper-phosphide (Cu-P), copper-tin (Cu-Sn), and copper selenide (Cu2Se). A comprehensive investigation of the electrocatalysts was conducted using advanced …


Activity Descriptors As Tools For Designing Highly Efficient Electrocatalysts For Water Splitting, Aya Gomaa Jun 2024

Activity Descriptors As Tools For Designing Highly Efficient Electrocatalysts For Water Splitting, Aya Gomaa

Theses and Dissertations

There is an uprising urge to design efficient, active, and durable catalysts to achieve sustainable hydrogen production. The unambiguity of which material should be used pushed the scientific community to devote enormous efforts in exploring different elements with different ratios on trial and error bases. However, the bridge between the theoretical calculation and the experiments introduced a new realm of designing efficient catalysts by introducing the concept of activity descriptors. In the first part of the thesis, the ability to convert waste stainless steel (SS) 316L meshes into highly efficient and durable oxygen evolution reaction (OER) catalysts is demonstrated. The …


Use Of Nanoparticle Additives To Achieve Desirable Properties In Fluorine-Free Firefighting Foams, Annelise Kathleen Curtin Jun 2024

Use Of Nanoparticle Additives To Achieve Desirable Properties In Fluorine-Free Firefighting Foams, Annelise Kathleen Curtin

USF Tampa Graduate Theses and Dissertations

Class B Firefighting foams play a crucial role in protecting equipment and people fromliquid fuel fires but concerns regarding the impacts of per- and poly-fluoroalkyl substances (PFAS) have resulted in bans on the use of aqueous film forming foam (AFFF). Fluorine-free replacements are yet to achieve the same level of performance. Nanoparticles including silica and clay have been used to improve foam stability, especially in environments where hydrocarbon fuels are present. These materials have also been used in solid composites to improve fire resistance. The stability of aqueous foams containing silica and Laponite RD nanoparticles along with surfactants of different …


Department Chairs As Change Agents: A Virtual Cross-Institutional Professional Development Model For Chairs, Cinzia Cervato, Stephanie Peterson, Carrie Ann Johnson, Canan Bilen-Green, Carla Koretsky, Adrienne Minerick, Gul Okudan Kremer Jun 2024

Department Chairs As Change Agents: A Virtual Cross-Institutional Professional Development Model For Chairs, Cinzia Cervato, Stephanie Peterson, Carrie Ann Johnson, Canan Bilen-Green, Carla Koretsky, Adrienne Minerick, Gul Okudan Kremer

Michigan Tech Publications

Department chairs are crucial in impacting departmental climate, conveying expectations, and providing merit assessments. Therefore, they have the most influence in retaining highly qualified faculty. Most department chairs come from the faculty ranks and lack formal training in key management, communication, and administrative skills, including performance reviews, resource allocation and budgeting, legal and compliance issues, promotion and tenure determinations, conflict resolution, and the inclusive management of people with diverse identities. Recognizing the critical role of department chairs and the evident gap in their training, we developed a series of chair workshops to provide ongoing professional development for department chairs across …


Emergent Magnetism And Hyperthermia In Phase- And Size-Tunable Iron Oxide Nanostructures, K Mudiyanselage Tharindu Supun Bandara Attanayake Jun 2024

Emergent Magnetism And Hyperthermia In Phase- And Size-Tunable Iron Oxide Nanostructures, K Mudiyanselage Tharindu Supun Bandara Attanayake

USF Tampa Graduate Theses and Dissertations

Iron oxide nanoparticles (IONPs) hold immense potential across diverse fields, from spintronics, magnetic hyperthermia to drug delivery, biodetection, and magnetic resonance imaging. Unlocking these applications hinges on our ability to tailor the magnetic properties of IONPs, and this dissertation presents novel and powerful approaches for enhancing magnetic and hyperthermic responses of multiphase iron oxide nanostructures. This is achieved by manipulating their phase volume fraction, size, and shape with a focus on the magnetic tunability of nanostructures via strategic control over structural and environmental parameters. The aforementioned has been achieved by the following three key approaches: (i) phase-tunability of iron oxide …


Chemical Herding As A Multiplicative Factor For Top-Down Manipulation Of Colloids, Mark N. Mcdonald, Douglas R. Tree, Cameron K. Peterson Jun 2024

Chemical Herding As A Multiplicative Factor For Top-Down Manipulation Of Colloids, Mark N. Mcdonald, Douglas R. Tree, Cameron K. Peterson

Faculty Publications

Colloidal particles can create reconfigurable nanomaterials, with applications such as color-changing, self-repairing, and self-regulating materials and reconfigurable drug delivery systems. However, top-down methods for manipulating colloids are limited in the scale they can control. We consider here a new method for using chemical reactions to multiply the effects of existing top-down colloidal manipulation methods to arrange large numbers of colloids with single-particle precision, which we refer to as chemical herding. Using simulation-based methods, we show that if a set of chemically active colloids (herders) can be steered using external forces (i.e., electrophoretic, dielectrophoretic, magnetic, or optical forces), then a larger …