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Articles 1561 - 1590 of 33288
Full-Text Articles in Entire DC Network
Functional Utility Of Gold Complexes With Phosphorus Donor Ligands In Biological Systems, Adedamola S. Arojojoye, Samuel G. Awuah
Functional Utility Of Gold Complexes With Phosphorus Donor Ligands In Biological Systems, Adedamola S. Arojojoye, Samuel G. Awuah
Chemistry Faculty Publications
Metallo-phosphines are ubiquitous in organometallic chemistry with widespread applications as catalysts in various chemical transformations, precursors for organic electronics, and chemotherapeutic agents or chemical probes. Here, we provide a comprehensive review of the exploration of the current biological applications of Au complexes bearing phosphine donor ligands. The goal is to deepen our understanding of the synthetic utility and reactivity of Au-phosphine complexes to provide insights that could lead to the design of new molecules and enhance the cross-application or repurposing of these complexes.
Effect Of Single Screw Extrusion Process Parameters On Gel Formation And Properties In Polycaprolactone Films, Kitthanya Ritthichai
Effect Of Single Screw Extrusion Process Parameters On Gel Formation And Properties In Polycaprolactone Films, Kitthanya Ritthichai
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research focuses on the production of polycaprolactone (PCL) films using the commercial grade CAPA 6800 through a continuous single-screw extrusion process. This method serves as an alternative to conventional solution-based film fabrication that requires solvents and chemical reagents. The effects of processing temperature (80–120 °C), screw design (mixing screw and plain screw), and extruder-barrel cooling system (water-cooled and air-cooled) on film quality, gel formation, thermal properties, and mechanical properties of PCL films were investigated. Based on the processing of high-purity PCL pellets, the results indicate that the processing temperature, screw design, and barrel-cooling system did not affect the chemical …
Raw Data For Tailoring High Entropy Borides For Hydrogenation: The Influence Of Crystal Morphology And The Exploration Of Catalytic Pathways, Michael Yeung, Ting Wang
Raw Data For Tailoring High Entropy Borides For Hydrogenation: The Influence Of Crystal Morphology And The Exploration Of Catalytic Pathways, Michael Yeung, Ting Wang
Chemistry Department Faculty Scholarship
The high entropy boride (HEB) Al0.2Nb0.2Pt0.2Ta0.2Ti0.2B2, with its unique crystal structure and high coordination (platinum coordinated to 12 borons), has been shown in our previous work to exhibit exceptional catalytic properties, especially in sulfur-rich environments, where traditional platinum catalysts would succumb to sulfur-poisoning. In this work, we investigate the mechanism of the HEB catalyst, first by comparing the synthesis by flux growth, as previously reported, to an arc melted preparation. It is evident that the aluminum flux growth synthesis encourages the growth of single crystals, with clear and defined crystal facets, whereas the arc melted sample results in poorly defined …
Raw Data For A Mild Alkaline Hydrothermal Etchant For Mbene Exfoliation, Michael Yeung
Raw Data For A Mild Alkaline Hydrothermal Etchant For Mbene Exfoliation, Michael Yeung
Chemistry Department Faculty Scholarship
Abstract for data:
Raw data for the journal publication, A Mild Alkaline Hydrothermal Ethant for MBene Exfoliation. ReadMe file provided.
Abstract for journal publication:
MoBene (the boride equivalent of MXenes) has been a synthetic challenge because borides degrade in common etching media. Inspired by the intercalation of lithium ions into AlOOH, we hypothesized that a hydrothermal route enables lithium ions to intercalate the aluminum layer of MoAlB and further separate the MoB sheet apart. Here, MoBene is first synthesized through a mild hydrothermal etching method with dilute lithium hydroxide. X-ray diffraction showed a peak at 8.9°, confirming an exfoliated layered …
Toward Biocompatible Assessment Of N-15 Hyperpolarized Metronidazole For Hypoxia Sensing, Faisal Asif
Toward Biocompatible Assessment Of N-15 Hyperpolarized Metronidazole For Hypoxia Sensing, Faisal Asif
Wayne State University Theses
Recent advances in hyperpolarization, particularly Signal Amplification by Reversible Exchange (SABRE), have enhanced molecular magnetic resonance imaging (MRI) for in vivo applications. This study investigates [15N3]metronidazole, a tri-nitrogen-labeled derivative of an FDA-approved antibiotic, as a hypoxia-sensitive imaging agent. Under hypoxic conditions, the nitroimidazole group undergoes stepwise reduction to an amino group, inducing significant 15N chemical shift changes (30–600 ppm). We aim to develop an iridium catalyst-free, biocompatible hyperpolarized (HP) [15N3]metronidazole formulation exhibiting robust polarization (up to 15%) and extended T1 lifetimes (~10 min). Three specific objectives guide this work: (1) formulation of a HP injectable with enhanced 15N detection, (2) …
Durable Oxyfluoride Waste Forms For Salt Wastes From Molten Salt Reactors, Alevtina A. Maksimova, Jake W. Amoroso, Matthew Page, Gregory Morrison, Hans Conrad Zur Loye
Durable Oxyfluoride Waste Forms For Salt Wastes From Molten Salt Reactors, Alevtina A. Maksimova, Jake W. Amoroso, Matthew Page, Gregory Morrison, Hans Conrad Zur Loye
Faculty Publications
Molten salt reactors (MSRs) are promising technology to replace traditional light and heavy water reactors in the near future. Waste management for MSRs, however, remains a pressing concern that needs to be resolved prior to realizing deployment of MSRs. Specifically, the generated salt waste needs to be safely sequestered, a task made difficult by the high solubility of the salt waste that can cause the release of radionuclides into the environment. This work demonstrates a new approach to immobilize multiple fluoride salts into a single waste form by converting highly-soluble fluorides to durable and stable oxyfluorides. Notably, we report a …
Eugenol Loaded Calcium Citrate Particle As A Ph Triggered Drug Release System And A Reducing Agent For Au (Iii), Sadia Afrin
Eugenol Loaded Calcium Citrate Particle As A Ph Triggered Drug Release System And A Reducing Agent For Au (Iii), Sadia Afrin
Dissertations and Theses
The study demonstrated that eugenol affects the morphology of calcium citrate particles during their formation, as confirmed by SEM micrography and PXRD analysis. Coating of eugenol loaded calcium citrate particles (CaCit MPs) with casein improves their known pH-dependent drug release profile, as confirmed by UV absorption spectroscopy. The casein-coated eugenol-loaded CaCit MPs (CCaCit(eu) MPs) can effectively control and sustain drug release under different pH conditions, particularly at acidic pH values (4.8 and 5.5), which mimics the environment of tumor tissues. To further explore the biomedical applications of calcium citrate, a bulk nanostructured precursor to the known anti-cancer calcium citrate phosphate-based …
Zinc Or Swim: Investigating Zinc Pollution From Restoration Materials, Megan R. Jensik
Zinc Or Swim: Investigating Zinc Pollution From Restoration Materials, Megan R. Jensik
Honors Undergraduate Theses
Zinc is an essential nutrient, but can be toxic at high concentrations, negatively affecting various biological functions. Gabions are galvanized metals coated in zinc that are used for many human purposes, including coastal restoration efforts attempting to avoid using plastic materials. However, gabions can degrade in marine environments, potentially leaching metal into the water and soil. There is a knowledge gap regarding the occurrence and impacts of zinc pollution in the areas where these gabions are deployed, including the Indian River Lagoon (IRL). To address this, sediment samples were collected from the IRL and analyzed for their physical and chemical …
The Relevance Of Dnajb1 Protein Dimerization Against The Human Neurodegenerative Diseases, Erina Kotreli, Trang Le, Szymon Ciesielski
The Relevance Of Dnajb1 Protein Dimerization Against The Human Neurodegenerative Diseases, Erina Kotreli, Trang Le, Szymon Ciesielski
Dean's Leadership Council Library Research Prize
All biological functions in living organisms depend on the activity of proteins, long molecules that must twist and fold into specific shapes to become functional. A subset of proteins known as molecular chaperones is essential for maintaining cellular health by assisting other proteins in folding correctly and refolding those damaged by stress. When proteins misfold and clump together, they can form toxic aggregates linked to many neurodegenerative diseases, including Alzheimer’s disease (AD), one of the leading causes of death in the United States. In AD, these protein aggregates form organized, elongated structures referred to as amyloid-like fibrils, which damage neurons …
William Albert Noyes Jr. And A Systemic Study Of The Near Ultraviolet Photochemical Decomposition Of Acetone, Zildjan Bonita
William Albert Noyes Jr. And A Systemic Study Of The Near Ultraviolet Photochemical Decomposition Of Acetone, Zildjan Bonita
Natural Sciences Student Research Presentations
Prior Knowledge
- Chemists observed that acetone vapor decomposes under UV light producing CO and hydrocarbons. The problem with their data was that it was inconsistent due to uncontrolled experimental variables (Herr and Noyes 2052–2053).
- Quantum yield data varied widely, pressure, temperature, and light intensity had never been systematically analyzed (Herr and Noyes 2052–2053).
- Noyes and Herr wanted to create a quantitative, controlled measurements to clarify the mechanisms of acetone photolysis (Herr and Noyes 2052–2053).
Importance of Acetone IV
- Serves as a fundamental model for photochemical bond cleavage (Journal of the American Chemical Society).
- Tests core photochemical laws (absorption → excitation …
Stephen J. Lippard: Chemistry Meets Medicine, Radwa Elrouby
Stephen J. Lippard: Chemistry Meets Medicine, Radwa Elrouby
Natural Sciences Student Research Presentations
Key Study
In "DNA Sequence Context Modulates the Impact of a Cisplatin 1,2-GpG Intrastrand Cross-Link", Pilch, Todd, and Lippard found that the DNA sequence around the binding site influences how tightly cisplatin binds (Pilch, Todd, and Lippard).
Biophysical techniques like melting temperature and circular dichroism showed that some sequences stabilize DNA more strongly after drug binding (Pilch, Todd, and Lippard).
This explains why cisplatin is more effective in some tumor genomes (Todd and Lippard).
Experiment 1--Density, Measurement And Significant Figures, Kevin Mark, Phil Mercier
Experiment 1--Density, Measurement And Significant Figures, Kevin Mark, Phil Mercier
Open Educational Resources
Lab objectives:
- To identify an unknown metal by measuring and calculating its density
- To determine the density of an unknown liquid by graphing mass and volume data
- To compare the accuracy and precision of water mass using measurements from a beaker and burette
Multi-Attribute Characterization Of Polymeric And Lipid-Based Drug Delivery Systems By Column Switching Liquid Chromatography-Mass Spectrometry, Brady W. Drennan
Multi-Attribute Characterization Of Polymeric And Lipid-Based Drug Delivery Systems By Column Switching Liquid Chromatography-Mass Spectrometry, Brady W. Drennan
Chemistry & Biochemistry Dissertations - Archive
Drug delivery systems (DDS) are an increasingly relevant technology, owing to their ability to provide controlled release and to enable the use of otherwise toxic or labile therapeutics. However, these modalities are complex, containing a multitude of species with diverse chemical and physical properties. Their characterization, which involves the assessment of critical quality attributes (CQAs), requires numerous analytical techniques. The high-throughput demands of the biopharmaceutical industry have driven the need to consolidate these characterizations into a single analytical method. Consequently, novel analytical technologies are needed to support multi-attribute characterization. A multimodal liquid chromatography–mass spectrometry (LC–MS) system was developed to facilitate …
Structure–Property Relationships Mediated By Lone Pairs And Vacancies In Oxychalcogenides: A Combined Experimental And Theoretical Study, Hoa Hn Nguyen
Chemistry & Biochemistry Dissertations - Archive
Structure–property relationships in some oxychalcogenide materials are strongly governed by the interplay between stereochemically active lone pairs and anion vacancy formation. Through a combination of density functional theory (DFT), synchrotron and neutron total scattering and optical characterization, this work elucidates how local symmetry breaking, chemical substitution, and vacancy dynamics influence electronic and optical behavior across several lone pair-containing systems. In crystalline TeO2, all three polymorphs exhibit wide band gaps with Te4+ 5s2 lone pairs contributing significantly near the valence band edge. Oxygen vacancy formation is thermodynamically favorable and induces asymmetric charge redistribution and enhanced polarizability, supporting …
Determination Of Structural Factors Contributing To Protection Of Zinc Fingers In Estrogen Receptor Α Through Molecular Dynamic Simulations, Patricia B. Lutz, Wesley R. Coombs, Craig A. Bayse
Determination Of Structural Factors Contributing To Protection Of Zinc Fingers In Estrogen Receptor Α Through Molecular Dynamic Simulations, Patricia B. Lutz, Wesley R. Coombs, Craig A. Bayse
Chemistry & Biochemistry Faculty Publications
The ERα transcription factor that induces tumor growth is a potential target for breast cancer treatment. Each monomer of the ERα DNA-binding domain (ERαDBD) homodimer has two conserved (Cys)4-type zinc fingers, ZF1 (N-terminal) and ZF2 (C-terminal). Electrophilic agents release Zn2+ by oxidizing the coordinating Cys of the more labile ZF2 to inhibit dimerization and DNA binding. Microsecond-length molecular dynamics (MD) simulations show that greater flexibility of ZF2 in the ERαDBD monomer leaves its Cys more solvent accessible and less shielded from electrophilic attack by sulfur-centered hydrogen bonds than ZF1 which is buried in the protein. In the …
Unraveling Visible Spectra Of S-Type Stars: The F3Δ–A3Δ (Α System) And E3Π–A3Δ (Β System) Band Systems Of Zro, Manish Bhusal, Peter Bernath, Jacques Liévin
Unraveling Visible Spectra Of S-Type Stars: The F3Δ–A3Δ (Α System) And E3Π–A3Δ (Β System) Band Systems Of Zro, Manish Bhusal, Peter Bernath, Jacques Liévin
Chemistry & Biochemistry Faculty Publications
ZrO has many low-lying states, and its spectra are essential for the characterization of S-type stars. A high-resolution emission spectrum recorded with a Fourier transform spectrometer at the National Solar Observatory is used for the analysis. The 0–0 and 1–0 bands of the f³Δ-a³Δ system (α system) and the 0–0 band of the e³Π-a³Δ system (β system) have been rotationally analyzed using the modern spectral fitting program PGOPHER. New ab initio calculations of transition dipole moments have been performed to determine the band strengths. These band strengths are used to produce line lists that are suitable for the …
Phytochemical Analysis, Antioxidant, And Antibacterial Properties Of Partition Fractions Of Adansonia Digitata And Annona Muricata Extracts Using Chloroform, Ethyl Acetate, Ethanol, And Aqueous Solvent Systems, Fagbohun Oyenike Bushirat, Hassan Abdusalam Adewuyi, Sakariyau Adio Waheed, Maryam Nana Musa, Timothy God-Giveth Olusegun, Ayomide Babatunde Ishola, Agumage Idoko, Adeola Victor Kolawole, Adesanmi Adefunmilayo Oluwatuyi, Sarah Ngozi Agwasim
Phytochemical Analysis, Antioxidant, And Antibacterial Properties Of Partition Fractions Of Adansonia Digitata And Annona Muricata Extracts Using Chloroform, Ethyl Acetate, Ethanol, And Aqueous Solvent Systems, Fagbohun Oyenike Bushirat, Hassan Abdusalam Adewuyi, Sakariyau Adio Waheed, Maryam Nana Musa, Timothy God-Giveth Olusegun, Ayomide Babatunde Ishola, Agumage Idoko, Adeola Victor Kolawole, Adesanmi Adefunmilayo Oluwatuyi, Sarah Ngozi Agwasim
Chemistry & Biochemistry Faculty Publications
Adansonia digitata and Annona muricata are traditionally used medicinal plants with reported pharmacological properties. In this study, we aimed to elucidate the phytochemical composition, antioxidant activity, and antibacterial properties of partition fractions of Adansonia digitata and Annona muricata extracts obtained using chloroform, ethyl acetate, ethanol, and aqueous solvent systems. The plant extracts were successively partitioned using chloroform, ethyl acetate, ethanol, and aqueous solvent systems. Phytochemical analysis was performed using standard methods. Antioxidant activity was evaluated using FRAP and DPPH assays. Antibacterial activity was assessed using agar well diffusion and MIC determination. Phytochemical analysis revealed the presence of alkaloids (10.2-15.6%), flavonoids …
The Importance Of Solution Studies For The Structural Characterization Of The Enterovirus 5' Cloverleaf, Morgan G. Daniels, Meagan E. Werner, Xiaobing Zuo, Steven M. Pascal
The Importance Of Solution Studies For The Structural Characterization Of The Enterovirus 5' Cloverleaf, Morgan G. Daniels, Meagan E. Werner, Xiaobing Zuo, Steven M. Pascal
Chemistry & Biochemistry Faculty Publications
Enteroviruses initiate genomic replication via a highly conserved mechanism that is controlled by an RNA platform, also known as the 5' cloverleaf (5'CL). Here, we present a biophysical analysis of the 5'CL conformation of three enterovirus serotypes under various ionic conditions, utilizing CD spectroscopy, size-exclusion chromatography, and small-angle X-ray scattering. In general, a tendency toward a smaller monomeric hydrodynamic radius in the presence of salts was observed, but the exact structural signature of each 5'CL varied depending upon the serotype. Rhinovirus B14 (RVB14) exhibited at least two monomeric conformations and a low propensity for dimerization, while poliovirus 1 (PV1) showed …
Scope And Mechanism Of The Ruthenium-Catalyzed Sp3 C–H Coupling Reaction Of 2-Alkylindoles With Enones For The Synthesis Of Carbazole Derivatives, Krishna Prasad Gnyawali, Mina Son, Donghun Hwang, Nuwan Asanka Pannilawithana, Mu-Hyun Baik, Chase S. Yi
Scope And Mechanism Of The Ruthenium-Catalyzed Sp3 C–H Coupling Reaction Of 2-Alkylindoles With Enones For The Synthesis Of Carbazole Derivatives, Krishna Prasad Gnyawali, Mina Son, Donghun Hwang, Nuwan Asanka Pannilawithana, Mu-Hyun Baik, Chase S. Yi
Chemistry Faculty Research and Publications
The catalytic system consisting of a cationic Ru–H complex 1 and 3,4,5,6-tetrachloro-1,2-benzoquinone (L1) was found to be highly effective for the dehydrative sp3 C–H coupling reaction of 2-alkyl substituted indoles with enones to form 2,4-disubstituted carbazole products. The analogous coupling reaction of 2-alkylindoles with linear enones bearing the cyclic olefinic group afforded tetracyclic carbazole products. A normal deuterium kinetic isotope effect was measured from the coupling reaction of 1,2-dimethylindole versus 1-methyl-2-(methyl-d3)indole with (E)-3-penten-2-one (kH/kD = 2.5). The Hammett plot was constructed from the reaction of para-substituted …
Synthesis Of Bio-Orthogonal Hydrogels For 3d Cell Culture Via Penicillamine Β-Thiolactone-Mediated Native Chemical Ligation, Kaelin E. Marshall, Matthew E. Currier, Nathan J. Oldenhuis
Synthesis Of Bio-Orthogonal Hydrogels For 3d Cell Culture Via Penicillamine Β-Thiolactone-Mediated Native Chemical Ligation, Kaelin E. Marshall, Matthew E. Currier, Nathan J. Oldenhuis
Honors Theses and Capstones
Many hydrogel systems designed to mimic the extracellular matrix (ECM) employ thiol-based chemistries with undesirable functional groups, including vinyl sulfones and methacrylates. In downstream applications, any unreacted functional groups are problematic and render hydrogels non-viable for human use. Here, we introduce modifications to the Native Chemical Ligation (NCL) mechanism, exploring the elimination of cytotoxic byproducts and increased reaction rate by using a β-thiolactone. The inclusion of the β-thiolactone results in retention of the thiol within the gel, as well as enhanced kinetics due to the thermodynamic favorability of the ring opening and amide formation. We achieved this by functionalizing 4-arm …
Production Of Graphene From Graphite Via Flash Joule Heating Process, Siranut Sirathanutworakan
Production Of Graphene From Graphite Via Flash Joule Heating Process, Siranut Sirathanutworakan
Chulalongkorn University Theses and Dissertations (Chula ETD)
Graphene is a material with unique properties and high potential. Due to its outstanding characteristics in strength, electrical and thermal conductivity, and flexibility, graphene is considered one of the materials of the future that can be used to enhance the efficiency of various emerging technologies. This research focuses on the synthesis of graphene using the Flash Joule Heating (FJH) process, during which an extremely high temperature occurs within milliseconds. The carbon precursor is rapidly exposed to intense heat, resulting in the dissociation of all chemical bonds in its structure and the reorganization of carbon atoms into a new graphene structure. …
Data-Driven Predictive Model For Various Shapes Of Gold Nanoparticle Synthesis Based On Self-Organizing Maps, Thanapol Khamhla
Data-Driven Predictive Model For Various Shapes Of Gold Nanoparticle Synthesis Based On Self-Organizing Maps, Thanapol Khamhla
Chulalongkorn University Theses and Dissertations (Chula ETD)
This work presents a machine learning framework that simultaneously classifies the shape and predicts the localised surface plasmon resonance (LSPR) wavelength of gold nanoparticles (AuNPs) purely from synthesis conditions. The dataset used to train the model consist of synthesis conditions and the corresponding AuNPs characteristics, including spherical, star, plate, and rod shapes with their measured LSPR wavelengths, were compiled from existing literatures. Our model first classifies synthesis conditions into clusters according to their resulting shape and then builds local regression models for each shape, enabling both classification and quantitative prediction within a single framework. The proposed model integrates the clustering …
ซีโอไลต์นาโน Hzsm-5 สำหรับการฟื้นฟูสภาพตัวทำละลายเอมีนที่ใช้งานแล้ว, สรัญนุช ยั่งยืน
ซีโอไลต์นาโน Hzsm-5 สำหรับการฟื้นฟูสภาพตัวทำละลายเอมีนที่ใช้งานแล้ว, สรัญนุช ยั่งยืน
Chulalongkorn University Theses and Dissertations (Chula ETD)
การดักจับคาร์บอนไดออกไซด์หลังการเผาไหม้ ด้วยตัวทำละลายเอมีนเป็นเทคโนโลยีที่ได้รับความนิยม แต่มีข้อจำกัดสำคัญคือภาระพลังงานสูงในขั้นฟื้นฟูตัวทำละลาย งานวิจัยนี้จึงมุ่งศึกษาการฟื้นฟูสารละลายเอมีนผสม 2-amino-2-methyl-1-propanol (AMP) และ 1-(2-hydroxyethyl)pyrrolidine (1-(2-HE)PRLD) อัตราส่วน 1:1 ความเข้มข้นรวม 4 M โดยเสริมประสิทธิภาพด้วยตัวเร่งปฏิกิริยาซีโอไลต์นาโน HZSM-5 เพื่อเพิ่มประสิทธิภาพการคายซับคาร์บอนไดออกไซด์ ตัวเร่งปฏิกิริยานาโน HZSM-5 ถูกสังเคราะห์ด้วยวิธีไฮโดรเทอร์มัลภายใต้สภาวะต่าง ๆ ได้แก่ อุณหภูมิการตกผลึก (110–180 °C) ระยะเวลาการตกผลึก (1–3 วัน) และระยะเวลาบ่มเจล (16–48 ชั่วโมง) วิเคราะห์ตัวเร่งปฏิกิริยาด้วย BET, XRD, FE-SEM, XPS, Py-FTIR และ NH3-TPD ก่อนนำไปทดสอบการคายซับคาร์บอนไดออกไซด์ ที่ 90 °C ในสารละลาย AMP:1-(2-HE)PRLD ผลการทดลองพบว่า สภาวะที่เหมาะสมในกระบวนการสังเคราะห์ ตัวเร่งปฏิกิริยาคืออุณหภูมิ 150 °C ระยะเวลาตกผลึก 3 วันและบ่มเจล 48 ชั่วโมง ซึ่งมีขนาดอนุภาคเฉลี่ยเท่ากับ 81 nm ส่งผลทำให้มีพื้นที่ผิว และมีกรดเบรินส์เตดสูงเท่ากับ 344 m2/g และ 0.013 mmol/g ตามลำดับ เมื่อทดสอบประสิทธิภาพการคายซับคาร์บอนไดออกไซด์ พบว่าอัตราการคายซับคาร์บอนไดออกไซด์เริ่มต้น ความจุการดูดซับ เท่ากับ 45.72 mol/min และ 1.29 mol CO2/L ตามลำดับ นอกจากนี้ยังพบว่า ภาระทางความร้อนมีค่าเท่ากับ 36.87 kJ/mol CO2 ซึ่งต่ำกว่ากรณีที่ใช้ตัวเร่งปฏิกิริยาเชิงพาณิชย์ ร้อยละ 41% ผลการศึกษานี้พบว่า AMP:1-(2-HE)PRLD ร่วมกับนาโน HZSM-5 เป็นแนวทางที่มีศักยภาพสูงสำหรับการพัฒนาเทคโนโลยีดักจับคาร์บอนไดออกไซด์แบบใช้พลังงานต่ำในระดับอุตสาหกรรม
การสังเคราะห์แกรฟีนควอนตัมดอตฐานกรดฮิวมิกและการประยุกต์เป็นสารเคลือบเซนเซอร์ตรวจจับความเครียด, ปริตตา จูฑาภักติ
การสังเคราะห์แกรฟีนควอนตัมดอตฐานกรดฮิวมิกและการประยุกต์เป็นสารเคลือบเซนเซอร์ตรวจจับความเครียด, ปริตตา จูฑาภักติ
Chulalongkorn University Theses and Dissertations (Chula ETD)
แกรฟีนควอนตัมดอต (GQDs) ถูกสังเคราะห์จากกรดฮิวมิก (HA) ที่เป็นสารตั้งต้นด้วยการใช้หม้อทอดไฟฟ้าด้วยวิธีไฮโดรเทอร์มอล ซึ่งในงานวิจัยนี้มุ่งเน้นการศึกษาตัวแปรที่เกี่ยวข้องกับกระบวนการสังเคราะห์ GQDs ด้วยการเปลี่ยนแปลงอัตราส่วนของกรดฮิวมิกที่ใช้สังเคราะห์และศึกษาผลของตัวโดป จากผลการศึกษาพบว่าตัวโดปที่ใช้ในการะบวนการสังเคราะห์ GQDs ที่เหมาะสมคือ เอทิลีนไดเอมีน (EDA) และจากผลการทดลองแสดงให้เห็นว่า GQDs ที่ใช้ EDA มีความเข้มแสงฟลูออเรสเซนต์สูงสุดที่ 66 หน่วยที่ความยาวคลื่น 467 นาโนเมตร (ช่วงแสงเขียวอมฟ้า) เมื่ออัตราส่วนกรดฮิวมิกต่อเอทิลีนไดอะมีนเท่ากับ 10 : 0.5 (มิลลิกรัม : มิลลิลิตร) ขนาดเฉลี่ยของอนุภาคอยู่ที่ 6.68 นาโนเมตร ซึ่งถูกวิเคราะห์โดยกล้องจุลทรรศน์อิเล็กตรอนแบบส่องผ่าน และการวัดขนาดอนุภาค เทคนิคสเปกตรัมฟลูออเรสเซนซ์ และการดูดกลืนรังสี ตามลำดับ โครงสร้างกราฟิติกของ GQDs ถูกยืนยันด้วยสเปกโทรสโกปีรามาน ดังนั้นในงานวิจัยนี้จึงสนใจที่จะนำ GQDs ที่ใช้ EDA เป็นตัวโดปไปประยุกต์ใช้งานเป็นสารเคลือบเรืองแสงที่นำไปเคลือบลงบนยางซิลิโคนเพื่อนำไปประยุกต์ใช้เป็นสารเคลือบเซนเซอร์ตรวจจับความเครียด พบว่า ความเข้มของแสงฟลูออเรสเซนต์ของสารเคลือบเรืองแสง GQDs มีแนวโน้มลดลงเมื่อเวลาเวลาผ่านไป แต่สามารถหดกลับคืนใกล้เคียงสภาพเดิมเมื่อปล่อยการให้แรง และเมื่อเทียบค่าความเข้มของแสงฟลูออเรสเซนต์ของแต่ละอัตราส่วน พบว่า ที่อัตราส่วนกรดฮิวมิกต่อเอทิลีนไดอะมีนเท่ากับ 50 : 0.5 (มิลลิกรัม : มิลลิลิตร) มีค่าเข้มแสงของแสงฟลูออเรสเซนต์สูงที่สุด
การเตรียมคาร์บอนแบคทีเรียเซลลูโลสและควอนตัมดอตจากน้ำหมึกของหมึกกระดองสำหรับใช้งานตกแต่งสำเร็จสิ่งทอ, มณฑิชา สันติภาพมณฑล
การเตรียมคาร์บอนแบคทีเรียเซลลูโลสและควอนตัมดอตจากน้ำหมึกของหมึกกระดองสำหรับใช้งานตกแต่งสำเร็จสิ่งทอ, มณฑิชา สันติภาพมณฑล
Chulalongkorn University Theses and Dissertations (Chula ETD)
การพัฒนาวัสดุนาโนคาร์บอนและควอนตัมดอต เพื่อประยุกต์ใช้เป็นสารตกแต่งสำเร็จสิ่งทอเพื่อเพิ่มคุณสมบัติพิเศษ คาร์บอนนาโนไฟเบอร์และคาร์บอนควอนตัมดอตเป็นวัสดุนาโนที่มีสมบัติเด่นด้านความแข็งแรง การนำไฟฟ้า และการเรืองแสง ขอบเขตของงานวิจัยนี้ประกอบด้วยการเตรียม คาร์บอนนาโนไฟเบอร์จากแบคทีเรียเซลลูโลส (BC-CNF) และการสังเคราะห์ควอนตัมดอต (QDs) จากน้ำหมึกของหมึกกระดอง ซึ่งเป็นการสังเคราะห์ทางชีวภาพ ในส่วนของการเตรียม BC-CNF ได้มีการดัดแปรงโครงสร้างด้วยปฏิกิริยาซัลโฟเนต เพื่อให้ได้สาร BC-CNF-SO3- ซึ่งผลการวิเคราะห์ยืนยันการเกิดหมู่ฟังก์ชันซัลโฟเนต และอนุภาคในระดับซับไมครอน โดยมีขนาดอนุภาคเฉลี่ย 1.6218 ไมโครเมตร และสามารถกระจายตัวในน้ำได้ดี เมื่อนำ BC-CNF-SO3- มาตกแต่งสำเร็จบนผ้าพอลิเอสเทอร์ พบว่าความสามารถในการดูดซึมน้ำของผ้าเพิ่มขึ้น โดยผ้าที่ใช้ความเข้มข้นร้อยละ 3 ให้ประสิทธิภาพดีที่สุด ด้วยเวลาดูดซึมน้ำเฉลี่ยเพียง 2 วินาทีหลังการซัก ซึ่งแสดงถึงความคงทนต่อการซักที่ดี ในส่วนของการสังเคราะห์ QDs จากน้ำหมึกของหมึกกระดอง พบว่าอนุภาคมีขนาดอยู่ในช่วง 4-6 นาโนเมตร และแสดงความสามารถในการเรืองแสงภายใต้แสงอัลตราไวโอเลต โดยการเติมเอทิลีนไดเอมีน (EDA) ในปริมาณ 2 มิลลิลิตร ให้ค่าความเข้มของการเรืองแสงสูงสุด เมื่อนำ สารละลายควอนตัมดอตจากน้ำหมึกที่สังเคราะห์โดยเติมเอทิลีนไดเอมีน 2 มิลลิลิตร (EDA 2) ที่สังเคราะห์มาตกแต่งสำเร็จบนผ้าไนลอน พบว่าปริมาณ สารละลายควอนตัมดอตจากน้ำหมึกของหมึกกระดองที่สังเคราะห์โดยเติมเอทิลีนไดเอมีน 2 มิลลิลิตร (EDA 2) โดยใช้สารละลายปริมาตร 1 มิลลิลิตร ให้ความเข้มการเรืองแสงสูงสุด โดยก่อนซัก ค่าโดยประมาณ 180–190 a.u. และหลังซัก ค่าโดยประมาณ 110–120 a.u. โดยมีความคงทนต่อการซักดี ผลการวิจัยสรุปได้ว่า การประยุกต์ใช้ในการตกแต่งสำเร็จสิ่งทอ สามารถเพิ่มความสามารถในการดูดซึมน้ำของผ้าพอลิเอสเทอร์ และความสามารถในการเรืองแสงบนผ้าไนลอน
Characterization And Leaching Feasibility Studies Of Copper Flue Dust For The Recovery Of Main And Trace Metals, Fardis Nakhaei, Marek Locmelis, Lana Alagha, Michael S. Moats, Carlos Eyzaguirre, Cory Smith
Characterization And Leaching Feasibility Studies Of Copper Flue Dust For The Recovery Of Main And Trace Metals, Fardis Nakhaei, Marek Locmelis, Lana Alagha, Michael S. Moats, Carlos Eyzaguirre, Cory Smith
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
Although copper smelter dust (CSD) is classified as hazardous waste, it also serves as a valuable secondary resource, offering potential for the recovery of critical elements. In this study, CSD samples were collected from the waste heat boiler (WHB) and electrostatic precipitator (ESP) units connected to the flash smelting furnace at a copper smelter. The representative samples were extensively characterized by particle size, and chemical and mineralogical analyses. Following sample characterization, leaching experiments were performed to evaluate the potential extraction of Cu, Fe, As, Zn, Pb, In, Ga, and Ge from the flue dusts. Distilled water, H2SO4, and HCl were …
M Star Opacities: The B³Π–X³Δ Band System Of Tio, Peter F. Bernath, Manish Bhusal, Mirek R. Schmidt
M Star Opacities: The B³Π–X³Δ Band System Of Tio, Peter F. Bernath, Manish Bhusal, Mirek R. Schmidt
Chemistry & Biochemistry Faculty Publications
The spectra of titanium monoxide (TiO) are used to classify M stars. TiO experimental cross sections based on a high-resolution emission spectrum recorded with a Fourier transform spectrometer at the National Solar Observatory are used for the analysis of the TiO B³Π–X³Δ transition (𝛾' system). The 3–2 and 4–3 vibrational bands are analyzed for the first time, and the analysis of the 2–1 band is revised. The transition dipole moment function from an ab initio calculation is used to calculate the band strengths. These band strengths are used to produce a B³Π–X³Δ line list for the vibrational levels v' ⩽ …
Atmospheric Chemistry Experiment (Ace) Winds, Matthew Wyatt, Peter F. Bernath, Chris Boone, Léo Lavy, Ryan Johnson
Atmospheric Chemistry Experiment (Ace) Winds, Matthew Wyatt, Peter F. Bernath, Chris Boone, Léo Lavy, Ryan Johnson
Chemistry & Biochemistry Faculty Publications
The Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) uses limb geometry to measure transmittance spectra of Earth's atmosphere by solar occultation. Line-of-sight wind speeds can be derived via Doppler shifts of molecular lines in infrared spectra. The wind look direction angles relative to geodetic North are derived from geometry. We validate the new ACE version 5.3 (v.5.3) line-of-sight winds with MIGHTI and meteor radar vector wind observations and find a ±15 m/s sunrise/sunset shift above 80 km. We also compare line-of-sight winds from ACE-FTS v.5.2 and v.5.3 with vector winds from the MERRA-2, HWM14, and WACCM-X models. A ±15 m/s …
Evaluating The Chemical Reactivity Of Wildfire-Derived Dissolved Organic Molecules: Glutathione Binding Through Kendrick Mass Defect Analysis, Hannah M. Hamontree, Patrick G. Hatcher
Evaluating The Chemical Reactivity Of Wildfire-Derived Dissolved Organic Molecules: Glutathione Binding Through Kendrick Mass Defect Analysis, Hannah M. Hamontree, Patrick G. Hatcher
Chemistry & Biochemistry Faculty Publications
The emerging risks to organisms of pyrogenic-derived dissolved organic matter (PyDOM) from forest fires are of concern due to its toxic and mutagenic potential (e.g., pro-oxidative responses in fauna through the depletion of glutathione, a nitrogen- and sulfur-containing tripeptide found in cells). This study simulates this phenomenon in a laboratory setting by identifying bonding between reduced l-glutathione and organic molecules in leachates from environmentally weathered biomass samples (charred and uncharred) using Kendrick Mass Defect (KMD) analysis from formula lists obtained from negative-mode electrospray ionization-Fourier transform-ion cyclotron resonance-mass spectrometry ((-)ESI-FT-ICR-MS). These formula lists reveal a 10-fold increase in nitrogen- and sulfur-containing …
The Importance Of Atomic Charges For Predicting Site-Selective Ir-, Ru-, And Rh-Catalyzed C-H Borylations, Shannon M. Stephens, Kyle M. Lambert
The Importance Of Atomic Charges For Predicting Site-Selective Ir-, Ru-, And Rh-Catalyzed C-H Borylations, Shannon M. Stephens, Kyle M. Lambert
Chemistry & Biochemistry Faculty Publications
A supervised machine learning model has been developed that allows for the prediction of site selectivity in late-stage C-H borylations. Model development was accomplished using literature data for the site-selective (≥95%) C-H borylation of 189 unique arene, heteroarene, and aliphatic substrates that feature a total of 971 possible sp² or sp³ C-H borylation sites. The reported experimental data was supplemented with additional chemoinformatic descriptors, computed atomic charges at the C-H borylation sites, and data from parameterization of catalytically active tris-boryl complexes resulting from the combination of seven different Ir-, Ru-, and Rh-based precatalysts with eight different ligands. Of the over …