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2023

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Articles 1321 - 1350 of 1539

Full-Text Articles in Chemistry

Modelling And Simulation Of Chemical Reaction Of Porous Mgcl2 Pellets With Nh3 By Including Impact Of Heat And Mass Transfer And Structure Change, Zeynep Karakaş Helvaci, Gürkan Karakaş, Yusuf Uludağ Jan 2023

Modelling And Simulation Of Chemical Reaction Of Porous Mgcl2 Pellets With Nh3 By Including Impact Of Heat And Mass Transfer And Structure Change, Zeynep Karakaş Helvaci, Gürkan Karakaş, Yusuf Uludağ

Turkish Journal of Chemistry

The MgCl2?NH3 reactive system is investigated in terms of heat and mass transfer coupled with chemical reaction through numerical simulation. The reversible nature of the chemical reaction is captured by including adsorption and desorption terms in the rate expression simultaneously. The kinetic coefficients of the adsorption are directly adopted from the literature, while those for the desorption reaction are calculated based on the thermodynamic relations. The impact of changing pressure and pellet porosity are also investigated in the simulations. The initial temperature of the pellet is 300 K in all simulations. Temperature, NH3 pressure, and conversion distributions in the pellets, …

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Synthesis Of Copper Nano/Microparticles Via Thermal Decomposition And Their Conversion To Copper Oxide Film, Çağdaş Allahverdi̇ Jan 2023

Synthesis Of Copper Nano/Microparticles Via Thermal Decomposition And Their Conversion To Copper Oxide Film, Çağdaş Allahverdi̇

Turkish Journal of Chemistry

Copper nano/microparticles were synthesized in octadecene at 290 °C by thermal decomposition method. Copper acetate monohydrate, stearic acid, and 1-octadecanol were used as copper precursor, capping and mild reducing agents, respectively, at the synthesis. Borosilicate glass substrates submerged into the reaction solution during the synthesis were coated by copper nano/ microparticles. Thermal decomposition and coating techniques were combined in this study. Copper nano/microparticles were thoroughly characterised via X-ray powder diffraction, X-ray photoelectron, Raman, and attenuated total reflectance-Fourier transform infrared spectroscopies, and scanning and transmission electron microscopies. The average minimum Feret?s diameter of these synthesized copper particles was measured as ~87 …

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Theoretical Investigation Of Steric Effects On The S1 Potential Energy Surface Of O-Carborane-Anthracene Derivatives, Fahri̇ Alkan Jan 2023

Theoretical Investigation Of Steric Effects On The S1 Potential Energy Surface Of O-Carborane-Anthracene Derivatives, Fahri̇ Alkan

Turkish Journal of Chemistry

TDDFT scan calculations were performed for s-carborane-anthracene derivatives (o-CB-X-Ant where X=-H, -CH3, -C2H5 and tert-butyl or -tBu) in order to understand the interplay between the steric effects, S1 potential energy surface (PES) and photophysical properties. The results show that all systems exhibit three local minima on the S1 PES, which correspond to the emissive LE and TICT state, along with the nonemissive CT state respectively. In the case of the unsubstituted system (o-CB-H-Ant), and -CH3 and -C2H5 substituted cases, S1 PES is predicted to be quite flat for certain conformations indicating that it is possible for these systems to reach …

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Investigation Of Boron Adsorption By Graphene Oxide: Equilibrium, Kinetic, And Thermodynamic Studies, Mehmet Fati̇h Önen, Nalan Erdöl Aydin, Osman Eksi̇k, Peli̇n Demi̇rci̇vi̇, Gülhayat Saygili Jan 2023

Investigation Of Boron Adsorption By Graphene Oxide: Equilibrium, Kinetic, And Thermodynamic Studies, Mehmet Fati̇h Önen, Nalan Erdöl Aydin, Osman Eksi̇k, Peli̇n Demi̇rci̇vi̇, Gülhayat Saygili

Turkish Journal of Chemistry

Graphene oxide, which has a great application in industry, is one of the promising carbonous materials. Modified Hummers method was applied to synthesize graphene oxide. Characterization techniques showed that pure graphene oxide was successfully obtained. Its adsorptive properties were investigated by boron adsorption. The results were demonstrated that boron adsorption on graphene oxide was a pH-dependent process and maximum adsorption was achieved at pH 6 (0.98 mg g?1). Langmuir adsorption capacity was calculated as 3.92 mg g?1 with R2 = 0.99. The kinetic data brought to light that pseudosecond-order kinetic model was well described the experimental data (R2 = 0.99), …

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Computational Comparison Of Platinum, Base Metals, And Binary Intermetallic Compounds’ Efficiency In Hydrogenation Catalysis, Lauren M. Sayler Jan 2023

Computational Comparison Of Platinum, Base Metals, And Binary Intermetallic Compounds’ Efficiency In Hydrogenation Catalysis, Lauren M. Sayler

Graduate Theses/Dissertations

In the petroleum industry, platinum is used as a catalyst in hydrogenation reactions during petroleum refining. Although platinum is extremely effective as a catalyst, it is expensive. This is an investigation into platinum and what characteristics make it so efficient, with the end goal of finding intermetallic compounds composed of base metals that are as effective in hydrogenation catalysis. The metals used in this investigation are Fe, Co, Ni, Mo, and W. The research performed here is computational and used to support and direct decisions made in the laboratory. The computation is first-principle, which is accomplished using Vienna Ab initio …

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Development Of Electrochemical Biosensor For Detection Of Thyroid–Stimulating Hormone, Kittirat Kitticharoenwiwat Jan 2023

Development Of Electrochemical Biosensor For Detection Of Thyroid–Stimulating Hormone, Kittirat Kitticharoenwiwat

Chulalongkorn University Theses and Dissertations (Chula ETD)

This dissertation focused on the development of electrochemical paper-based immunosensor for determining thyroid-stimulating hormone (TSH) using a label-free immunoassay. Thyroid-stimulating hormone is a pituitary hormone that stimulates the thyroid gland to produce thyroid hormones for the body’s metabolism. The current electrochemiluminescence method for determining TSH as a specific biomarker indicating congenital hypothyroidism (CHT) onset is unfortunately restricted to laboratory settings, thereby resulting in limited practical utilization, delayed diagnosis, and severe outcomes. Herein, we proposed a simple, rapid, portable, and sensitive electrochemical biosensor with a label-free format based on bovine serum albumin (BSA)/graphene oxide (GO) nanocomposite for TSH determination. Caboxylated GO …

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Bamboo Biochar For Bar Adsorptive Microextraction Of Parabens In Water, Maytinee Jantorn Jan 2023

Bamboo Biochar For Bar Adsorptive Microextraction Of Parabens In Water, Maytinee Jantorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this research, bamboo biochar bar was prepared in the form of small-sized rods using starch as a binder and applied as a sorbent in bar adsorptive microextraction (BAµE) of parabens (methyl paraben, ethyl paraben, propyl paraben and butyl paraben) in water. The mixture of bamboo biochar which has a size of 60-80 mesh, a surface area of 102.6 m²g-1 and a pore size of 0.7 nm and starch in a weight ratio of 1:13 gave the good mechanical stability and high removal efficiency of parabens. When applied the bamboo biochar bar as a sorbent, the optimum conditions for BAµE …

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Selective Photodegradation Of Food Contaminants Using Titania-Silica-Iron Oxide Nanocomposites With Molecularly Imprinted Technology, Mehak Un Nisa Jan 2023

Selective Photodegradation Of Food Contaminants Using Titania-Silica-Iron Oxide Nanocomposites With Molecularly Imprinted Technology, Mehak Un Nisa

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this study, magnetic imprinted photocatalysts (Fe3O4@SiO2@TiO2@MIP and Fe3O4@SiO2@MIP@TiO2) have been synthesized successfully by surface molecular imprinting technique. 5,7-dimethoxy-coumarin was used as a dummy template to give specific recognition ability to AFB1. A range of analytical techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), vibrating sample magnetometer (VSM), and Branauer-Emmett-Teller (BET) were employed to study the crystal structure, morphology, and chemical composition of the nanocomposites. The HPLC-DAD was used to quantify the photodegradation efficiency of imprinted photocatalysts under different factors such as the source of irradiation light, initial concentration of analyte, amount of photocatalyst, and …

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Polyaniline/Cellulose Nanofiber/Polyvinyl Alcohol Hydrogel-Modified Screen-Printed Graphene Electrode For Cd2+ And Ni2+ Detection, Pichapon Boonkrong Jan 2023

Polyaniline/Cellulose Nanofiber/Polyvinyl Alcohol Hydrogel-Modified Screen-Printed Graphene Electrode For Cd2+ And Ni2+ Detection, Pichapon Boonkrong

Chulalongkorn University Theses and Dissertations (Chula ETD)

Heavy metal contamination in wastewater has been an environmental issue, so the determination of heavy metals by an accurate and simple method is important. In this work, polyaniline/cellulose nanofiber/polyvinyl alcohol hydrogel-modified screen-printed graphene electrode (PANI/CNF/PVA hydrogel-modified SPGE) was fabricated by combining the advantages of graphene and conductive hydrogel to increase the conductivity and preconcentrate the metal ions to fabricate the modified electrode for the simultaneous detection of Cd2+ and Ni2+. First, PANI/CNF nanocomposite was synthesized by in situ chemical polymerization, and CNF was shown to prevented PANI aggregation and provided sufficient porous structure on the modified electrode. The PANI/CNF nanocomposite …

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Synthesis And Evaluation Of Sorbicillinoids, Noah Devolve Jan 2023

Synthesis And Evaluation Of Sorbicillinoids, Noah Devolve

Honors Program Theses

Sorbicillinoids are a rich family of natural products that have intrigued and inspired scientists since their initial discovery in 1948. A recent report by Zhang et al. detailed the discovery of several new monomeric sorbicillinoids that are particularly interesting as they show nitric oxide (NO) inhibition in RAW264.7 monocyte cell assays and thus possess potential as anti-inflammatory agents. Based on this information, obtaining more of these novel compounds and establishing a preliminary structure activity relationship (SAR) could be achieved by modulating the substitution pattern on the molecules’ benzene ring and varying the alkyl chain length. To this end, a flexible …

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Feminist Pedagogy In Stem: The Intersection Of Stem Pedagogy And Feminist Theory, Lesley Ann Giddings, Candice Price Jan 2023

Feminist Pedagogy In Stem: The Intersection Of Stem Pedagogy And Feminist Theory, Lesley Ann Giddings, Candice Price

Chemistry: Faculty Publications

Science, technology, engineering, and mathematics (STEM) education aims to cultivate the capacity for innovation and real-world problem-solving (Marrero et al., 2014). However, STEM pedagogy has not historically aligned with this goal, often failing to teach students the necessary skills and mindset for creative problem-solving (Stehle & Peters-Burton, 2019). Traditional STEM pedagogical methods, such as rote and lecture-based learning, are based on the teacher being the dominant source of knowledge and students being the passive receivers (Achuonye, 2015; Khalaf & Mohammed Zin, 2018). These methods lack student support, collaboration, active learning, and real-world contexts (Gasiewski et al., 2012). Furthermore, the exclusion …

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Creating Meaningful Connections With The Electr Eating Meaningful Connections With The Electron Transport Chain Beyond A Virtual Classroom, Lesley Ann Giddings Jan 2023

Creating Meaningful Connections With The Electr Eating Meaningful Connections With The Electron Transport Chain Beyond A Virtual Classroom, Lesley Ann Giddings

Chemistry: Faculty Publications

At the center of feminist pedagogy is community. Creating community within the classroom and between the class and local communities increases student engagement and access to knowledge. Communities can be a source of solidarity and further decenter authority in the classroom, empowering students, teachers, and the surrounding community to be co-learners. Amid the COVID-19 pandemic, remote teaching posed challenges to student engagement. Here, I describe an assignment used to build an inclusive community of co-learners within a virtual biochemistry class and our local communities. Oxidative phosphorylation is a cellular process used to create energy that depends on the electron transport …

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Lead Induced Differences In Bone Properties In Osteocalcin +/+ And −/− Female Mice, G. Yildirim, W. C. Budell, O. Berezovska, S. Yagerman, S. S. Maliath, P. Mastrokostas, S. Tommasini, T. L. Dowd Jan 2023

Lead Induced Differences In Bone Properties In Osteocalcin +/+ And −/− Female Mice, G. Yildirim, W. C. Budell, O. Berezovska, S. Yagerman, S. S. Maliath, P. Mastrokostas, S. Tommasini, T. L. Dowd

Publications and Research

Lead (Pb) toxicity is a major health problem and bone is the major reservoir. Lead is detrimental to bone, affects bone remodelingand is associated with elderly fractures. Osteocalcin (OC) affects bone remodeling, improves fracture resistance and decreases with age and in some diseases. The effect of lead in osteocalcin depleted bone is unknown and of interest. We compared bone mineral properties of control and Pb exposed (from 2 to 6 months) femora from female adult C57BL6 OC+/+ and OC−/− mice using Fourier Transform Infrared Imaging (FTIRI), Micro-computed tomography (uCT), bone biomechanical measurements and serum turnover markers (P1NP, CTX). Lead significantly …

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Facile Synthesis Of Nite2-Co2Te2@Rgo Nanocomposite For High-Performance Hybrid Supercapacitor, Maziar Farshadnia, Ali A. Ensafi, Kimia Zarean Mousaabadi, Behzad Rezaei, Muslum Demir Jan 2023

Facile Synthesis Of Nite2-Co2Te2@Rgo Nanocomposite For High-Performance Hybrid Supercapacitor, Maziar Farshadnia, Ali A. Ensafi, Kimia Zarean Mousaabadi, Behzad Rezaei, Muslum Demir

Chemistry & Biochemistry Faculty Publications and Presentations

The design of bimetallic tellurides that exhibit excellent electrochemical properties remains a huge challenge for high-performance supercapacitors. In the present study, tellurium is consolidated on CoNi2@rGO for the first time, to synthesize NiTe2-Co2Te2@rGO nanocomposite by using a facile hydrothermal method. As-prepared NiTe2-Co2Te2@rGO nanocomposite was characterized by EDS, TEM, FESEM, Raman, BET, XRD, and XPS techniques to prove the structural transformation. Upon the electrochemical characterization, NiTe2-Co2Te2@rGO has notably presented numerous active sites and enhanced contact sites with the electrolyte solution during …

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On Chip Microfluidic Separation Of Cyclotides, Reza Didarian, Aliakbar Ebrahimi, Hamed Ghorbanpoor, Hesam Bagheroghli, Fatma Doğan Güzel, Mohsen Farhadpour, Nasrin Lotfibakhshayesh, Hossein Hashempour, Hüseyi̇n Avci Jan 2023

On Chip Microfluidic Separation Of Cyclotides, Reza Didarian, Aliakbar Ebrahimi, Hamed Ghorbanpoor, Hesam Bagheroghli, Fatma Doğan Güzel, Mohsen Farhadpour, Nasrin Lotfibakhshayesh, Hossein Hashempour, Hüseyi̇n Avci

Turkish Journal of Chemistry

Cyclotides as a cyclic peptide produced by different groups of plants have been a very attractive field of research due to their exceptional properties in biological activities and drug design applications. The importance of cyclotides as new biological activities from nature caused to attract researchers to develop new separation systems. Recent growth and development on chip-based technology for separation and bioassay especially for anticancer having sparklingly advantages comparison with common traditional methods. In this study, the microfluidic separation of Vigno 1-5 cyclotides extracted from Viola ignobilis by using polar and nonpolar forces as a liquid-liquid interaction was investigated through modified …

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Promoting Antihepatocellular Carcinoma Activity Against Human Hepg2 Cells Via Pyridine Substituted Palladium Complexes: In Vitro Evaluation And Qsar Studies, Öğünç Meral, Fati̇h Mehmet Emen, Emi̇ne Kutlu, Ruken Esra Demi̇rdöğen, Nesli̇han Kaya Kinaytürk, Görkem Kismali, Şevki̇naz Doğan Jan 2023

Promoting Antihepatocellular Carcinoma Activity Against Human Hepg2 Cells Via Pyridine Substituted Palladium Complexes: In Vitro Evaluation And Qsar Studies, Öğünç Meral, Fati̇h Mehmet Emen, Emi̇ne Kutlu, Ruken Esra Demi̇rdöğen, Nesli̇han Kaya Kinaytürk, Görkem Kismali, Şevki̇naz Doğan

Turkish Journal of Chemistry

Bis(4-(4-nitrobenzyl)pyridine)dichloropalladium(II), [PdCl$_{2}$L$^{1}$$_{2}$], bis(2-amino-5-bromopyridine)dichloropalladium(II), [PdCl$_{2}$L$^{2}$$_{2}$], bis(2,4-dimethylpyridine)dichloropalladium(II), [PdCl$_{2}$L$^{3}$$_{2}$], bis(3,4-dimethylpyridine)dichloropalladium(II), [PdCl$_{2}$L$^{4}$$_{2}$] were prepared. The spectroscopic techniques (FT-IR and $^{1}$H-NMR, $^{13}$C-NMR) were used to characterize the compounds. Theoretical calculations were used to validate the experimental results. The LanL2DZ-based DFT/B3LYP method was used to define the most stable possible molecular structure for the complexes. Potential energy distribution analysis was performed to determine the theoretical vibration bands of the complexes. Molecular electrostatic potential maps, boundary molecular orbitals and Mulliken charge distribution were used to determine the active sites of the molecules. The interaction mechanisms between the complexes and liver cancer protein were investigated via molecular docking. …

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Sars-Cov-2 Main Protease Targeting Potent Fluorescent Inhibitors: Repurposing Thioxanthones, Gönül Saadet Batibay, Eyüp Meti̇n Jan 2023

Sars-Cov-2 Main Protease Targeting Potent Fluorescent Inhibitors: Repurposing Thioxanthones, Gönül Saadet Batibay, Eyüp Meti̇n

Turkish Journal of Chemistry

The coronavirus disease, COVID-19, is the major focus of the whole world due to insufficient treatment options. It has spread all around the world and is responsible for the death of numerous human beings. The future consequences for the disease survivors are still unknown. Hence, all contributions to understand the disease and effectively inhibit the effects of the disease have great importance. In this study, different thioxanthone based molecules, which are known to be fluorescent compounds, were selectively chosen to study if they can inhibit the main protease of SARS-CoV-2 using various computational tools. All candidate ligands were optimized, molecular …

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A New Method In The Synthesis Of Conductive Polymers; Synthesis, Characterization, And Investigation Of Photocatalytic Properties Of Polyaniline, Muzaffer Can Jan 2023

A New Method In The Synthesis Of Conductive Polymers; Synthesis, Characterization, And Investigation Of Photocatalytic Properties Of Polyaniline, Muzaffer Can

Turkish Journal of Chemistry

As known, in the synthesis of conductive polyaniline polymer from aniline monomer, the polymerization medium must be acidic. In order to make the polymerization medium acidic, protonic acids such as HCl and H2SO4 are generally used. In this study, two acids have been used to make the polymerization medium acidic. One of them, as we know, is H2SO4 as a protonic acid. The other acid is the zinc ion, which is a Lewis acid. The metal ion has never been used for this purpose up to now. Two polyaniline polymers have been synthesized to prove that conductive polymers can also …

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การพัฒนาบล็อกคอนกรีตปูพื้นจากกากของเสียในกระบวนการเผาไหม้แบบฟลูอิไดซ์เบด, ณัฐวรรณ ดวงแก้ว Jan 2023

การพัฒนาบล็อกคอนกรีตปูพื้นจากกากของเสียในกระบวนการเผาไหม้แบบฟลูอิไดซ์เบด, ณัฐวรรณ ดวงแก้ว

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้ศึกษาการใช้ประโยชน์เถ้าลอย และทรายของเสีย (ขนาดละเอียดและหยาบ) จากกระบวนการเผาไหม้แบบฟลูอิไดซ์เบดเพื่อนำความร้อนมาใช้ในการอบแห้งในกระบวนการผลิตกระดาษ มาใช้เป็นวัตถุดิบในการเตรียมบล็อกคอนกรีต 2 ประเภทวัสดุ คือ คอนกรีตฐานปูนซีเมนต์ปอร์ตแลนด์ และคอนกรีตฐานจีโอพอลิเมอร์ สำหรับการเตรียมคอนกรีตฐานปูนซีเมนต์ปอร์ตแลนด์ ได้ศึกษาผลของการใช้เถ้าลอยทดแทนส่วนของปูนซีเมนต์ปอร์ตแลนด์ (วัสดุประสาน) และศึกษาอัตราส่วนของทรายของเสีย (มวลรวม) ต่อวัสดุประสาน ที่มีต่อสมบัติของคอนกรีต ขึ้นรูปด้วยวิธีการอัด บ่มชิ้นงานเป็นเวลา 1 7 และ 28 วัน พบว่าตัวอย่างที่มีเถ้าลอยทดแทนปูนซีเมนต์ปอร์ตแลนด์ร้อยละ 15 โดยน้ำหนักของวัสดุประสาน และมีอัตราส่วนของ มวลรวมต่อวัสดุประสาน เท่ากับ 1:1 โดยน้ำหนัก ที่อายุ 7 วัน มีค่ากำลังอัด 45 MPa เป็นไปตามมาตรฐาน มอก.827-2531 นอกจากนั้นยังได้นำส่วนผสมดังกล่าวมาเตรียมบล็อกประสานปูพื้นฐานปูนซีเมนต์ปอร์ตแลนด์ที่มีขนาดและรูปทรงตามมาตรฐานดังกล่าวด้วยเครื่องผลิตบล็อกคอนกรีต พบว่าสามารถเตรียมบล็อกประสานปูพื้นฐานปูนซีเมนต์ปอรต์แลนด์ที่มีเถ้าลอยทดแทนส่วนของปูนซีเมนต์ปอร์ตแลนด์ได้ ในส่วนของการศึกษาความเป็นไปได้ในการผลิตบล็อกฐานจีโอพอลิเมอร์เป็นการทดลองเตรียมจีโอพอลิเมอร์แบบส่วนเดียว โดยใช้เถ้าลอยร่วมกับสารแอลคาไลซึ่งประกอบด้วย โซเดียมซิลิเกตและโซเดียมไฮดรอกไซด์ (วัสดุประสาน) และผสมกับมวลรวมในสัดส่วนของวัสดุประสานต่อมวลรวมเท่ากับ 1:1 เช่นเดียวกับการเตรียมบล็อกคอนกรีตฐานซีเมนต์ ใช้อัตราส่วนผสมน้ำต่อวัสดุประสานเท่ากับ 0.31 ขึ้นรูปด้วยวิธีการอัด โดยศึกษาผลของสัดส่วนของเถ้าลอยต่อสารอัลคาไล และสัดส่วนของโซเดียมซิลิเกตต่อโซเดียมไฮดรอกไซด์ ที่มีต่อสมบัติของคอนกรีต พบว่าชิ้นงานที่ใช้เถ้าลอยร้อยละ 80 โดยน้ำหนักของวัสดุประสาน และใช้สารอัลคาไล (โซเดียมซิลิเกตต่อโซเดียมไฮดรอกไซด์เท่ากับ 60:40 โดยน้ำหนัก) ร้อยละ 20 โดยน้ำหนักของวัสดุประสาน ที่อายุ 28 วัน มีกำลังอัด 5.45 MPa ซึ่งเป็นค่าที่ต่ำกว่าค่าตามมาตรฐาน มอก.827-2531 จึงไม่สามารถใช้ทำบล็อกประสานปูพื้นได้ แต่ค่ากำลังอัดของบล็อกฐานจีโอพอลิเมอร์ก็สูงมากพอสำหรับผลิตบล็อกกลวงไม่รับน้ำหนักตาม มอก.58-2560

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Kinetic Mechanism Of Dimethylsulfone Monooxygenase And Its Immobilized Magnetic Nanoparticles, Montisa Mangkalee Jan 2023

Kinetic Mechanism Of Dimethylsulfone Monooxygenase And Its Immobilized Magnetic Nanoparticles, Montisa Mangkalee

Chulalongkorn University Theses and Dissertations (Chula ETD)

The dimethyl sulfone monooxygenase system is a two-component flavoprotein catalyzing the monooxygenation of dimethyl sulfone (DMSO2) by oxidative cleavage producing methanesulfinate and formaldehyde. The reductase component (DMSR) is a flavoprotein with FMN as a cofactor catalyzing flavin reduction using NADH. The oxygenase (DMSMO) uses reduced flavin from the reductase and oxygen for substrate monooxygenation. DMSMO can bind to FMN and FMNH– with a Kd of 17.4 ± 0.9 µM and 4.08 ± 0.8 mM, respectively. The binding of FMN to DMSMO is required prior to binding DMSO2. Substituting reduced DMSR with FMNH– demonstrated the same oxidation kinetics, indicating that FMNH- …

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การจำลองซีเอฟดีสามมิติของไรเซอร์ดักจับคาร์บอนไดออกไซด์แบบอุณหภูมิไม่คงที่ที่มีท่อน้ำหล่อเย็น, อลีนา ดำเนินสวัสดิ์ Jan 2023

การจำลองซีเอฟดีสามมิติของไรเซอร์ดักจับคาร์บอนไดออกไซด์แบบอุณหภูมิไม่คงที่ที่มีท่อน้ำหล่อเย็น, อลีนา ดำเนินสวัสดิ์

Chulalongkorn University Theses and Dissertations (Chula ETD)

แก๊สเรือนกระจกที่สำคัญและมีปริมาณมากที่สุดคือ แก๊สคาร์บอนไดออกไซด์ แก๊สคาร์บอนไดออกไซด์จากการผลิตไฟฟ้าถือเป็นแหล่งแก๊สเรือนกระจกที่สำคัญ เทคโนโลยีการดักจับแก๊สคาร์บอนไดออกไซด์ทำได้หลายวิธี เช่น การดักจับก่อนการเผาไหม้ การเผาไหม้ด้วยออกซิเจน และการดักจับหลังการเผาไหม้ การศึกษานี้มุ่งเน้นไปที่เทคโนโลยีการดักจับคาร์บอนไดออกไซด์หลังการเผาไหม้โดยใช้เครื่องปฏิกรณ์ฟลูอิไดซ์เบดแบบหมุนเวียนดักจับแก๊สคาร์บอนไดออกไซด์ออกจากแก๊สเผาไหม้ แก๊สเผาไหม้ถูกป้อนเข้าไปยังหอดูดซับเพื่อดูดซับคาร์บอนไดออกไซด์ก่อนที่จะปล่อยออกสู่ชั้นบรรยากาศ โพแทสเซียมคาร์บอเนตบนตัวรองรับแกมมา-อะลูมินาถูกใช้เป็นตัวดูดซับ การวิจัยนี้เป็นการพัฒนาแบบจำลองพลศาสตร์ของไหลเชิงคำนวณของเครื่องปฏิกรณ์ ฟลูอิไดซ์เบดแบบหมุนเวียนที่มีการติดตั้งท่อน้ำหล่อเย็นในไรเซอร์ซึ่งเป็นบริเวณที่เกิดการดักจับแก๊สคาร์บอนไดออกไซด์ อุณหภูมิในเครื่องปฏิกรณ์สามารถเปลี่ยนสมดุลของปฏิกิริยาเพื่อให้สามารถดักจับคาร์บอนไดออกไซด์ได้มากขึ้น เครื่องปฏิกรณ์จำลองเป็นรูปสี่เหลี่ยมจัตุรัสขนาด 0.05 x 0.05 ม. และสูง 1.1 ม. แบบจำลองทางคณิตศาสตร์ที่ใช้คือ แบบออยเลอเรียน-ออยเลอเรียน โดยได้เพิ่มสมการการเกิดปฏิกิริยาเคมีของโพแทสเซียมคาร์บอนเนต คาร์บอนไดออกไซด์ และน้ำเข้าไปด้วย จากการทดสอบแบบจำลองพบว่า จำนวนเซลล์ที่เหมาะสมที่ใช้ในการจำลองคือ 500,000 เซลล์ และช่วงเวลาที่ใช้ในการจำลองจะอยู่ที่ 250 - 500 วินาที ตัวแปรที่ใช้ศึกษาประกอบด้วย ความเร็วของแก๊สขาเข้า ความเร็วของน้ำหล่อเย็น และลักษณะการจัดเรียงท่อน้ำหล่อเย็นภายในหอดูดซับ จากการจำลองกระบวนการพบว่า ตัวแปรที่ส่งผลต่อประสิทธิภาพการดักจับแก๊สคาร์บอนไดออกไซด์ในหอดูดซับอย่างมีนัยสำคัญ คือ ความเร็วของแก๊สขาเข้า และ ลักษณะการจัดเรียงท่อน้ำหล่อเย็นภายในหอดูดซับ ส่วนความเร็วของน้ำหล่อเย็นไม่ส่งผลต่อประสิทธิภาพการดักจับแก๊สคาร์บอนไดออกไซด์อย่างมีนัยสำคัญ

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Development And Assessment Of Gamified Process-Oriented Guided Inquiry Learning Activities In Undergraduate Large Lecture Chemistry Courses, Nathan Turner Jan 2023

Development And Assessment Of Gamified Process-Oriented Guided Inquiry Learning Activities In Undergraduate Large Lecture Chemistry Courses, Nathan Turner

Electronic Theses and Dissertations

Students who take general chemistry and do not perform well are more likely to pursue an alternative degree or remove themselves from STEM curriculum entirely. Poor academic performance and high student attrition rates in general chemistry courses have resulted in the perception of chemistry courses being gatekeepers for students in pursuit of STEM degrees. Process-Oriented Guided Inquiry Learning (POGIL) has shown promising results in both lecture and laboratory teaching on student performance in chemistry while gamification has been used to enhance student learning experiences to help students grasp chemistry concepts. The current project blends two student-centered approaches, gamification and POGIL, …

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Development Of Novel Cellular Assay Model And Therapeutic Deep Eutectic Solvents To Optimize The Activity Of Anticancer Agents, Nizam Uddin Jan 2023

Development Of Novel Cellular Assay Model And Therapeutic Deep Eutectic Solvents To Optimize The Activity Of Anticancer Agents, Nizam Uddin

Electronic Theses and Dissertations

Multidrug resistance (MDR) is the major burden behind chemotherapeutic treatment failure. It is the principal mechanism by which cancer cells evade chemotherapeutic treatment. As a result, aggressive cancer cells survive and continue uncontrolled cell division. Multidrug resistance affects survival rate of almost all types of cancer patients and death toll rises at an alarming rate. There are seven different mechanisms for evolving MDR. The most common mechanism in efflux activity of overexpressed ABC transporters. MRP1 is a prominent ABC transporter that pumps out a wide variety of anticancer drugs from the cells and thereby reduces intracellular drug concentrations and develops …

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Design, Synthesis, And Biological Evaluation Of Novel Steroidal Analogs: Potential Anticancer Agents, Trevor Ostlund Jan 2023

Design, Synthesis, And Biological Evaluation Of Novel Steroidal Analogs: Potential Anticancer Agents, Trevor Ostlund

Electronic Theses and Dissertations

Cancer is a malicious disease with low survivability rates primarily due to lack of reliable treatment options. Treatments are often non-specific for patients, and cancer resistance to treatment is becoming more prevalent as fast as new therapies are created. Previous studies in our laboratory have focused on the Epidermal Growth Factor Receptor (EGFR) and its downstream kinase family members as a key target for cancer. This cascade controls cell proliferation, anti-apoptotic effects, cell regulation, and other survival factors. Additionally, ABC transporters, responsible for efflux of chemotherapeutic material from cells, are key targets to combat drug resistance. We first evaluated a …

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Comprehensive Analysis And Forensic Investigation Of Cyanide, Thiocyanate, And 2-Amino-2-Thiazoline-4-Carboxylic Acid In-Ante- And Postmortem Blood Utilizing Advanced Analytical Techniques, Abdullah Hamad Alluhayb Jan 2023

Comprehensive Analysis And Forensic Investigation Of Cyanide, Thiocyanate, And 2-Amino-2-Thiazoline-4-Carboxylic Acid In-Ante- And Postmortem Blood Utilizing Advanced Analytical Techniques, Abdullah Hamad Alluhayb

Electronic Theses and Dissertations

Cyanide (CN), present as cyanide anion (CN-) or hydrogen cyanide (HCN), is a deadly poison. The main mechanism of CN toxicity is blocking terminal electron transfer, leading to cellular hypoxia, cytotoxic anoxia, and potential death. Determining blood CN concen-trations along with its major metabolite, thiocyanate (SCN-), is crucial. A sensitive method for concurrent detection of CN and SCN- from human ante- and post-mortem blood via liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis was devel-oped. The method involved active microdiffusion with chemical modification using naph-thalene-2,3-dicarboxaldehyde (NDA) and taurine, while monobromobimane (MBB) mod-ification was used for SCN-. The method showed good sensitivity for …

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Synthesis And Kinetic Investigation Of Oxidation In A Palladium-Methyl System, Richard A. Cardrino , '23 Jan 2023

Synthesis And Kinetic Investigation Of Oxidation In A Palladium-Methyl System, Richard A. Cardrino , '23

Senior Theses, Projects, and Awards

The current industrial syngas process for transforming methane to methanol is an indirect process that requires the initial oxidation of methane to carbon monoxide with a subsequent reduction to form methanol under high pressure and temperature conditions. An alternative green chemical process is desirable, especially one that directly oxidizes gaseous methane to liquid methanol under mild conditions with an environmentally benign oxidant, such as dioxygen. The current study investigates the synthesis of a novel palladium complex with activated methane and the selective oxidation of this complex resulting in the liberation of methanol under more ambient conditions, a model system for …

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Exogenous Factors That Impact Huntingtin Aggregation, Adam Skeens Jan 2023

Exogenous Factors That Impact Huntingtin Aggregation, Adam Skeens

Graduate Theses, Dissertations, and Problem Reports (ETD)

While expansion of a polyglutamine (polyQ) domain is the immediate cause of huntingtin (htt) aggregation associated with Huntington’s Disease (HD), other cellular factors modify aggregation. These include interactions with cellular membranes, protein biding partners, molecular crowding, and proteinaceous seeds. Here, two important factors are biophysically characterized: 1) the interaction of htt with endomembranes and 2) proteinaceous seeds obtained from a variety of htt-derived peptides. In the first project, the aggregation of htt at bilayer interfaces and in the presence of divalent cations was investigated. A major cellular factor implicated in altered htt aggregation is the binding of lipids. Furthermore, the …

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Solid State Nmr Analysis Of Insect Wing Membranes, Samuel Eddy Jan 2023

Solid State Nmr Analysis Of Insect Wing Membranes, Samuel Eddy

Graduate Theses, Dissertations, and Problem Reports (ETD)

Solid State NMR is a powerful tool for analyzing the chemical composition of insects. Previous studies have used Solid State NMR to investigate the chemical composition and investigate the sclerotization (tanning) process of insect exoskeletons. Acquiring sufficient exoskeleton sample for analysis has been relatively simple. This is however not the case for other components of an insect’s physiology, particularly the wing membrane material. The wings of an insect only compose a small percentage of their overall body mass, and many hundreds to thousands of insects must be processed in order to achieve a few milligrams of wing membrane sample. The …

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Sound The (Smaller) Alarm: The Triphosphate Magic Spot Nucleotide Pgpp, Areej Malik, Megan A. Hept, Erin B. Purcell Jan 2023

Sound The (Smaller) Alarm: The Triphosphate Magic Spot Nucleotide Pgpp, Areej Malik, Megan A. Hept, Erin B. Purcell

Chemistry & Biochemistry Faculty Publications

It has recently become evident that the bacterial stringent response is regulated by a triphosphate alarmone (pGpp) as well as the canonical tetra- and pentaphosphate alarmones ppGpp and pppGpp [together, (p)ppGpp]. Often dismissed in the past as an artifact or degradation product, pGpp has been confirmed as a deliberate endpoint of multiple synthetic pathways utilizing GMP, (p)ppGpp, or GDP/GTP as precursors. Some early studies concluded that pGpp functionally mimics (p)ppGpp and that its biological role is to make alarmone metabolism less dependent on the guanine energy charge of the cell by allowing GMP-dependent synthesis to continue when GDP/GTP has been …

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Infrared Spectra Of Small Radicals For Exoplanetary Spectroscopy: Oh, Nh, Cn, And Ch: The State Of Current Knowledge, Svatopluk Civiš, Adam Pastorek, Martin Ferus, Sergei N. Yurchenko, Noor-Ines Boudjema Jan 2023

Infrared Spectra Of Small Radicals For Exoplanetary Spectroscopy: Oh, Nh, Cn, And Ch: The State Of Current Knowledge, Svatopluk Civiš, Adam Pastorek, Martin Ferus, Sergei N. Yurchenko, Noor-Ines Boudjema

Chemistry & Biochemistry Faculty Publications

In this study, we present a current state-of-the-art review of middle-to-near IR emission spectra of four simple astrophysically relevant molecular radicals—OH, NH, CN and CH. The spectra of these radicals were measured by means of time-resolved Fourier transform infrared spectroscopy in the 700–7500 cm−1 spectral range and with 0.07–0.02 cm−1 spectral resolution. The radicals were generated in a glow discharge of gaseous mixtures in a specially designed discharge cell. The spectra of short-lived radicals published here are of great importance, especially for the detailed knowledge and study of the composition of exoplanetary atmospheres in selected new planets. Today, …

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