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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 …

Effect Of Quince Seed Gum (Qsg) On The Performance Of Injectable Hyaluronic Acid Hydrogels In Terms Of The Rheological, Morphological, And Mechanical Aspect, Serdar Kolay, Ni̇lhan Kayaman Apohan, Erdi̇nç Babuç, Gökay Gün

Turkish Journal of Chemistry

Injectable hydrogels play an important role in tissue engineering as a filling and repairing material. This study aimed to develop a new injectable hydrogel based on hyaluronic acid (HA) and quince seed gum (QSG) and investigate the effect of QSG on hydrogel performance. The amount of unreacted 1,4-Butanediol diglycidyl ether (BDDE) is maintained at an undetectable level for HA-QSG hydrogels. Amino acid analysis showed that the HA-QSG hydrogel had rich amino acid concentrations of leucine, arginine, and valine. After thermal sterilization, the elastic modulus of HA-QSG gels for dermal and intra-articular filler applications is 63 Pa and 92 Pa respectively. …

Antiviral And Cytotoxic Activities And Chemical Profiles Of Two Species Of Abies Nordmanniana From Türkiye, Nazli Sarikahya, Gaye Sümer Okkali, Furkan Ozan Çöven, Sevda Zeinali̇, Gülce Gucur, Ayşe Di̇la Çağlar, Ece Uyar, Ahmet Ceyhan Gören, Ayşe Nalbantsoy

Turkish Journal of Chemistry

Abies is an important genus of the family Pinaceae, with about 50 species found in the highlands of Asia, Europe, North Africa, and North and Central America. The principal aim of the present work was to investigate the chemical content and biological potential of the resin and cone from Abies nordmanniana subsp. bornmulleriana and Abies nordmanniana subsp. equi-trojani, respectively. The flavonoid and phenolic contents of the resin and cones were evaluated using liquid chromatography-high resolution mass spectrometry (LC-HRMS). Additionally, the essential oil and fatty acid compositions were analyzed using gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detector (GC-FID).. Cytotoxicity …

Theoretical Study On The Insertion Reaction Of The Stannylenoid H2snlif With X-H Bonds (X = N, O, F), Shuo Wu, Bingfei Yan, Shaoli Liu, Wenzuo Li

Turkish Journal of Chemistry

The insertion reactions of p-complex (RP) and three-membered ring configuration (RS) of stannylenoid H2SnLiF with NH3, H2O and HF have been studied theoretically by quantum chemical calculation. The structures of reactants, precursors, transition states, intermediates and products have been fully optimized at the M06-2X/def2-TZVP level. The single point energy of all fixed points were calculated using the QCISD method. The calculation results show that the three-membered ring configuration is easier to conduct the insertion reaction. Comparing the reaction energy barriers of RP, RS to NH3, H2O and HF, we found that the difficulty of the insertion reaction is NH3 > H2O …

Senggani Fruit (Melastoma Malabathricum Linn.) Extract As A Natural Indicator In Ph-Responsive Pva-Taro Starch Plastic Packaging, Rika Risma Dewi, Intan Syahbanu, Winda Rahmalia

Turkish Journal of Chemistry

Polyvinyl alcohol (PVA)-starch-based bioplastics are widely used in many applications. pH-responsive plastic packaging was produced through the incorporation of senggani (Melastoma malabathricum Linn.) fruit extract into PVA-taro starch-based plastic packaging. The objective of this research was to examine the characteristics of senggani fruit extract under different pH conditions and explore its application as a pH indicator in intelligent packaging. The senggani fruit was extracted through the maceration method using a solvent comprising 96% ethanol and 3% citric acid, with a ratio of 85:15 (v/v). The senggani fruit extract solution underwent color changes, appearing pink at pH levels below 6, pale …

Design And Characterization Of Phosphonic Acid-Functionalized Grafted Sepiolite Nanohybrids And Their Adsorption Studies For Removal Of Copper Ions From Aqueous Solution, Mehwish Tahir, Asif Raza, Amara Nasir, Tariq Yasin, Shamila Imtiaz

Turkish Journal of Chemistry

In this study, we synthesized novel, economically efficient phosphonic acid-functionalized grafted sepiolite nanohybrids for selective elimination of copper ions from water. These nanohybrids were prepared by graft polymerization of glycidyl methacrylate onto sepiolite. We utilized free radical graft polymerization to graft glycidyl methacrylate (GMA) onto silanized sepiolite. The nanohybrids obtained exhibited a grafting percentage of 479% at 0.3 g of KPS initiator, 15% GMA monomer, and after 4 h of reaction. In pursuit of selectively removing metal ions from water, the nanohybrid with the highest grafting (PGE3) was chemically treated with phosphoric acid to introduce phosphonic acid groups on it. …

Rapid Synthesis Of Azoindolizine Derivatives Via Aryldiazonium Salts, Ferruh Lafzi̇

Turkish Journal of Chemistry

A practical, rapid, and efficient method for the synthesis of azoindolizine derivatives via aryldiazonium salts with excellent yields was reported. Firstly, the corresponding aniline derivatives were synthesized via a simple and rapid method. Then, the optimal reaction conditions were investigated using a variety of protic and aprotic solvents that demonstrating the robustness of the approach. Finally, the applicability of this method to various sources of indolizine and phenyldiazonium tetrafluoroborate salts was expanded.

Modeling Exciton Delocalization And Transport In Pdbd-T-2f With The Line-Dipole Improvement For Coupling Calculation, Brian Dvorak

College of Science and Health Theses and Dissertations

A non-atomistic representation of the conjugated polymer PDBD-T-2F was constructed to model exciton delocalization and transport in the material. A Hamiltonian was built in the site basis to model the energy transfer, using excitation energies calculated using density functional theory and inter-site through-space coupling values calculated with either density functional theory or the newly integrated line-dipole approximation. The Hamiltonian allowed calculation of the excitation energies available for each system, prediction of the absorption spectrum, and simulation of the dynamics of exciton transport. For realistic crystal sizes at room temperature, the model predicts a band gap at 1.9 eV with decreasing …

Heterogeneous Resources In Infrastructures Of The Edge Network Paradigm: A Comprehensive Review, Qusay S. Alsaffar, Leila Ben Ayed

Karbala International Journal of Modern Science

The late 1990s saw the rise of the edge computing network paradigm, as well as an increase in the number of IoT de-vices. This concept is viewed as a link between cloud servers and end-devices, bringing processing and storage re-sources closer to clients. As a result of its low latency and high performance, researchers and developers have expressed interest in it. However, this paradigm confronts a number of obstacles and restrictions, including restricted and hetero-geneous resources at network edges. In this paper, we provide a detailed review of heterogeneous resources in edge network infrastructures using a three-dimensional method. These three …

Incorporating Oxygen Isotopes Of Oxidized Reactive Nitrogen In The Regional Atmospheric Chemistry Mechanism, Version 2 (Icoin-Racm2), Wendell W. Walter, Masayuki Takeuchi, Nga L. Ng, Meredith G. Hastings

Faculty Publications

The oxygen isotope anomaly (Δ¹⁷O = δ¹⁷O − 0.52 × δ¹⁸O > 0) has proven to be a robust tool for probing photochemical cycling and atmospheric formation pathways of oxidized reactive nitrogen (NO_y). Several studies have developed modeling techniques to implicitly model Δ¹⁷O of NO_y molecules based on numerous assumptions that may not always be valid. Thus, these models may be oversimplified and limit our ability to compare model Δ¹⁷O values of NO_y with observations. In this work, we introduce a novel method for explicitly tracking Δ …

Zinc Oxide Nanostructures Synthesized By Hot Water Treatment For The Photocatalytic Degradation Of Organic Pollutants In Water, Ranjitha Kumarapuram Hariharalakshmanan

Theses and Dissertations

Photocatalysis using nanostructured semiconductors for the degradation of organic pollutants has received significant attention as an advanced water treatment method. A photocatalyst absorbs light with energy greater than or equal to its band gap and generates electron-hole pairs. These electrons and holes take part in redox reactions in water to generate reactive oxygen species, such as hydroxyl radicals and superoxide anions, which can break down organic contaminants. However, this method has some challenges, such as electron-hole recombination, which reduces the efficiency, high cost of nanostructure synthesis, and reduced durability of nanostructured photocatalysts in suspension form. The immobilization of photocatalyst nanostructures …

An Investigation Of The Mindset Context And Its Downstream Effects On Marginalized Student Outcomes In College Stem Courses, Ronia Naim Kattoum

Theses and Dissertations

Multiple national calls centered on critical thinking and social justice have been made to improve and reform higher education in science, technology, engineering, and mathematics (STEM) courses to increase the representation of students from marginalized groups in the STEM workforce and equip all students for success. To help answer this call, our project has two overarching goals: 1) Identify pathways to increase student success in STEM courses at a moderately selective metropolitan institution with a diverse population that can be generalized to similar institutions, and 2) determine how instructional practices influence perceptions of the learning environment, especially for marginalized students. …

A Speleogenetic History Of Novoafonskaya Cave In The Western Caucasus, Olga Chervyatsova, Sergey Potapov, Jonathan Baker, Dmitry Gavryushkin, Victor Polyak, Matt Heizler, Sergey Tokarev, Sergey Sadykov, Roman Dbar, Yuri Dublyansky

International Journal of Speleology

Speleogenesis in hypogene karst settings may be closely tied to regional tectonic dynamics and concomitant hydrochemical evolution of karst waters. However, placing temporal constraints on these processes can require a wider array of field observations and techniques than for typical karst systems. Herein, we present a comprehensive study of Novoafonskaya Cave (Western Caucasus, Abkhazia). The updated speleogenetic history of the cave comprises four stages: (1) the most ancient, a low-T hydrothermal (ca. 40–50°C) priming stage; (2) the main stage enabled by mixing of upwelling thermomineral and locally recharged common karst waters; (3) the late sulfuric-acid speleogenesis (SAS) stage, which left …

Modified Toulmin's Argumentation Model Based On Prior Experiences, Ali Hadi Hasan, Mohamad Ab. Saleh, Ahmed T. Sadiq

Karbala International Journal of Modern Science

Our work focuses on the usefulness of previously stored correct extracted results, which form a sort of stored knowledge got from previous experiences, from enhancing Toulmin's argument model that deals with drug conflict problems in therapeutic diagnostics. New patients are entered using friendly user interface to store in files and then they are matched with the records of previous results, patients’ symptoms and histories datasets which also contain the correct best drugs extracted results. If the new entered record of a patient is matching with any previous record then the correct result of drug will be found immediately and displayed. …

Design, Synthesis And Characterization Of Zinc And Gold-Based Metal-Organic Frameworks And Complexes For The Detection And Treatment Of Cancer, May Reda Mohamed

Thesis/ Dissertation Defenses

The early detection of cancer plays a pivotal role in improving patient outcomes, emphasizing the urgent need for highly sensitive and selective biosensing platforms. Metal-Organic Frameworks (MOFs) have emerged as promising candidates in this domain due to their tunable properties, large surface area, and high porosity. Herein, the utilization of zinc-based MOF as a sophisticated biosensing platform tailored for the precise detection of the HER2 cancer biomarker is presented. HER2, a critical protein marker in breast cancer diagnostics and treatment, demands highly selective and accurate detection methods for effective patient management. Simple hydrothermal synthesis methodology has been adopted to synthetize …

Nanoparticles As Antioxidant Agents: A Comprehensive Review, Sulyman Olalekan Ibrahim, Halimat Yusuf Lukman, Fatimat Ronke Abdulkadir, Monsurat Yemisi Bello, Yusuf Oloruntoyin Ayipo, Halimah Funmilayo Babamale, Marili Funmilayo Zubair, Olubunmi Atolani

Al-Bahir

This study seeks to provide a comprehensive overview of the latest progress in the antioxidant properties of nanoparticles. Nanoparticles (NPs) have emerged as a promising tool in several domains of science and industry, including their application as antioxidant agents. The main knowledge gaps seem to be in correctly identifying the make-up of the naturally occurring phytochemicals that give these nano-antioxidants their extraordinary pharmacology and drug-like properties. In many instances, that characterization is done using spectroscopy instrumentation such as fourier-transform Infrared (FT-IR), scanning electron microscope (SEM), and X-ray diffraction analysis (XRD). From literature appraisals, it was discovered that a lot of …

Predicting Rheology Of Uv-Curable Nanoparticle Ink Components And Compositions For Inkjet Additive Manufacturing, Cameron D. Lutz

Master's Theses

Inkjet additive manufacturing is the next step toward ubiquitous manufacturing by enabling multi-material printing that can exhibit various mechanical, electronic, and thermal properties. These characteristics are realized in the careful formulation of the inks and their functional materials, but there are many constraints that need to be satisfied to allow optimal jetting performance and build quality when used in an inkjet 3-D printer. Previous research has addressed the desirable rheology characteristics to enable stable drop formation and how the metallic nanoparticles affect the viscosity of inks. The contending goals of increasing nanoparticle-loading to improve material deposition rates while trying to …

General Chemistry Ii: Chem 2134, Subha Pratihar

ATU Faculty OER Books and Materials

No abstract provided.

Hatt-Flow: Hierarchical Attention-Flow Mechanism For Group-Activity Scene Graph Generation In Videos, Naga Venkata Sai Raviteja Chappa, Pha Nguyen, Thi Hoang Ngan Le, Page Daniel Dobbs, Khoa Luu

Electrical Engineering and Computer Science Faculty Publications and Presentations

Group-activity scene graph (GASG) generation is a challenging task in computer vision, aiming to anticipate and describe relationships between subjects and objects in video sequences. Traditional video scene graph generation (VidSGG) methods focus on retrospective analysis, limiting their predictive capabilities. To enrich the scene-understanding capabilities, we introduced a GASG dataset extending the JRDB dataset with nuanced annotations involving appearance, interaction, position, relationship, and situation attributes. This work also introduces an innovative approach, a Hierarchical Attention–Flow (HAtt-Flow) mechanism, rooted in flow network theory to enhance GASG performance. Flow–attention incorporates flow conservation principles, fostering competition …

Photodegradation Of Microplastics Through Nanomaterials: Insights Into Photocatalysts Modification And Detailed Mechanisms, Yiting Xiao, Yang Tian, Wenbo Xu, Jun Zhu

Biological and Agricultural Engineering Faculty Publications and Presentations

Microplastics (MPs) pose a profound environmental challenge, impacting ecosystems and human health through mechanisms such as bioaccumulation and ecosystem contamination. While traditional water treatment methods can partially remove microplastics, their limitations highlight the need for innovative green approaches like photodegradation to ensure more effective and sustainable removal. This review explores the potential of nanomaterial-enhanced photocatalysts in addressing this issue. Utilizing their unique properties like large surface area and tunable bandgap, nanomaterials significantly improve degradation efficiency. Different strategies for photocatalyst modification to improve photocatalytic performance are thoroughly summarized, with a particular emphasis on element doping and heterojunction construction. Furthermore, this review …

Moss Biomonitoring Of Lead Emissions From Hillsboro Airport, Daria Kolpakov

University Honors Theses

The objective of this experiment was to use biomonitoring as a method to determine lead concentration levels around Hillsboro Airport in Hillsboro, Oregon. Twenty-two samples were collected within a 2 km radius around Hillsboro Airport using a randomized sampling strategy. The concentrations of lead within the samples were determined using ICP-MS. The average lead concentration was (2.8 ± 5.0) mg/kg with a peak value of 21.6 mg/kg 0.57 km from Hillsboro Airport. As the average lead concentration was substantially skewed, Hillsboro Airport is likely to be the source of the lead increase.

Design, Synthesis And Characterization Of Zinc And Gold-Based Metal Organic Frameworks And Complexes For The Detection And Treatment Of Cancer, May Reda Mohamed

Dissertations

The early detection of cancer plays a pivotal role in improving patient outcomes, emphasizing the urgent need for highly sensitive and selective biosensing platforms. Metal-Organic Frameworks (MOFs) have emerged as promising candidates in this domain due to their tunable properties, large surface area, and high porosity. Herein, the utilization of zinc-based MOF as a sophisticated biosensing platform tailored for the precise detection of the HER2 cancer biomarker is presented. HER2, a critical protein marker in breast cancer diagnostics and treatment, demands highly selective and accurate detection methods for effective patient management. Simple hydrothermal synthesis methodology has been adopted to synthetize …

In Situ And 2d And 3d In Silico Redox Cycling Studies For Design Optimization Of Coplanar Arrays Of Microband Electrodes In A 70 Μm × 100 Μm Electroactive Footprint, Miguel Angel Abrego Tello, Mahsa Lotfi Marchoubeh, Ingrid Fritsch

Chemistry & Biochemistry Faculty Publications and Presentations

Optimization of redox-cycling currents was performed by adjusting the height (sidewalls, h), width (w), and length (l) of band electrodes and their spacing (w_gap) in coplanar arrays restricted to a small-electroactive window of 70 × 100 μm. These arrays can function in μL-volumes for chemical analysis (e.g., in-vivo dopamine detection using probes). Experiments were conducted with an array of five electrodes (NE = 5), w = 4.3 μm, w_gap = 3.7 μm, h = 0.150 μm, and l = 99.2 μm. Reasons for …

Modeling Charging Current Dynamics At Microelectrodes And Their Interfaces With Electrolyte And Insulators With A Focus On Microfabricated Gold Microband Electrodes On An Su-8 Substrate, Miguel Angel Abrego Tello, Mahsa Lotfi Marchoubeh, Ingrid Fritsch

Chemistry & Biochemistry Faculty Publications and Presentations

The suitability of electrochemical methods for quantitative measurements at microdevices is influenced by the relatively large electrode-insulator interface-to-electrode area ratio, greatly impacting charging dynamics due to interactions among electrolyte, conductor material, and insulator layers. The resulting charging current can overwhelm the faradaic current from redox chemistry. The device studied here features a 70 μm × 100 μm electroactive window, hosts gold coplanar microband electrodes, and is insulated by SU-8, which serves as both overlayer and substrate. The overlayer defines the electroactive length and isolates the leads of the electrodes from the sample solution. Cyclic voltammetry in 0.10 M …

Development Of Highly Efficient Hybridfunctionalized Membranes For Sustainable Water Harvesting, Ahmed Z. Abuibaid

Dissertations

Water scarcity has emerged as a critical global challenge. This problem catches the world's interest through events such as the severe drought in Europe during the summer of 2022. While desalination plants offer a solution, their high energy consumption necessitates the exploration of alternative, sustainable water resources. Addressing the urgent need for alternative water resources in the face of increasing water scarcity. A viable option was presented by fog harvesting, which is a method to collect water from atmospheric fog. This method was initially developed to meet the demands of a variety of sectors such as agricultural purposes, and household …

Positron Emission Tomography In Oncology And Environmental Science, Samantha Delaney

Dissertations, Theses, and Capstone Projects

The last half century has played witness to the onset of molecular imaging for the clinical assessment of physiological targets. While several medical imaging modalities allow for the visualization of the functional and anatomical properties of humans and living systems, few offer accurate quantitation and the ability to detect biochemical processes with low-administered drug mass doses. This limits how physicians and scientists may diagnose and treat medical issues, such as cancer, disease, and foreign agents.

A promising alternative to extant invasive procedures and suboptimal imaging modalities to assess the nature of a biological environment is the use of positron emission …

Development And Applications Of Flexible Piezoelectric Nanogenerators Using Batio3, Pdms, And Mwcnts For Energy Harvesting And Sensory Integration In Smart Systems, Islam Uddin Shipu, Dipasree Bhowmick, Nondon Lal Dey

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Mechanical energy is a versatile and accessible green energy source, increasingly harnessed to power small-scale devices via innovative flexible piezoelectric nanogenerators (F- PNGs). These devices convert mechanical energy into electricity using lightweight materials such as Barium Titanate (BaTiO3), poly dimethyl siloxane (PDMS), and multi-walled carbon nanotubes (MWCNTs). In this design, BaTiO3 nanoparticles were embedded in a composite film with PDMS and MWCNTs, sandwiched between two copper electrodes. The BaTiO3/PDMS/MWCNT composite PENGs, synthesized for this study, produce an output voltage of ∼8 V through periodic cyclic beating. This represents an increase of about 16% compared to the PENGs without MWCNT doping. …

A Molecular Dynamics Study On The Destruction Mechanism Of Per And Polyfluoroalkyl Substances Due To Ultrasound Technology, Bruno Bezerra De Souza

Dissertations

Per- and polyfluoroalkyl substances (PFAS) are a group of stable synthetic chemicals that are highly persistent and harmful pollutants to the environment and human health. PFAS have caused a strong public and regulatory response due to their ubiquitous presence in the environment and toxicity to humans. The application of ultrasound is one of the most effective treatment technologies for the mineralization of PFAS in contaminated water. However, this technology is treated as a black box causing the inability to be optimized. Therefore, there is a pressing need to investigate the intricate dynamics of PFAS degradation under ultrasound to unlock its …

Molecular-To-Continuum Scale Modeling Of Aerosols: Atmospheric Application And Beyond, Ella Ivanova

Dissertations

Aerosol modeling is critical for various applications, such as climate forecasting, air quality, and human health impact assessment. During their lifetime, aerosols undergo a complex evolution, usually divided into several stages — formation, processing, transport, and removal — that occur on different scales. Thus, the choice of modeling methods depends on the stage considered. For example, certain stages of particle formation may require nano-scale modeling while aerosol-cloud interactions span from microscale to mesoscale. This study examines the modeling of aerosol behavior over a wide range of scales, from nano to microscale, with implications to mesoscale.

This dissertation focuses on two …

2-Tertbutylfuran At 550 And 700 K: A Multiplexed Photoionization Mass Spectrometric Investigation And Determination Of Cross Sections Of A Carbon- Bromine Bond And Various Brominated Organic Compounds, Ameyali Tapia

Master's Theses

This thesis presents the combustion study of 2-tertbutylfuran (2-TBF) in reaction with atomic oxygen (O(3P)). Data was collected at the Advanced Light Source (ALS) of the Lawrence Berkeley National Lab, using tunable vacuum ultraviolet radiation coupled with a multiplexed mass spectrometer to acquire the data. These data were taken at low pressures of 7 and 8 torr at temperatures of 550 K and 700 K, respectively. Primary products of the system were identified and characterized, while reaction pathways of the products are currently being studied to ensure thermodynamic feasibility. Branching fractions of the system were also calculated, to view the …