Chemistry Commons^™

Mechanistic Analysis Of Reductive Boracarboxylation Using Low Valent Copper And Co2, Notashia Nicole Baughman

Graduate Theses, Dissertations, and Problem Reports (ETD)

The synthesis of organoboron compounds is of contemporary importance in the chemistry community given their utility in subsequent functionalization reactions as well as their growing therapeutic potential in the treatment of human disease. This, coupled with the ubiquity of carboxylic acid functional groups in pharmaceuticals and fine chemicals, has led to interest in one-pot difunctionalization reactions using CO₂ and a boron source. An (ICy)copper(I)-catalyzed boracarboxylation reaction was recently developed wherein CO₂ and a pinacolboryl group is added across the double bond of vinyl arenes was recently developed, providing access to α-aryl-β-boryl propionic acid derivatives. A subsequent publication detailed …

Development Of New Synthetic Methods For Carbon Nanohoops, Merfat Aljhdli

Graduate Theses, Dissertations, and Problem Reports (ETD)

Carbon nanotubes have received much attention from the material chemists after the synthesis and structure analysis by Iijima in 1991. It was envisioned that cycloparaphenylenes (CPPs), which comprise a sequence of benzene units connected at para position to make a cyclic ring structure, are possible templates for growing carbon nanotubes of a single chirality and single diameter for nanotechnology application. Recently, chemists turned their attention to synthesizing aromatic carbon nanobelts proposed as a general term for carbon molecules composed of fused benzene rings in cylindrical structure shape. Cyclophenacenes (CPAs) as carbon nanobelts are expected to be more suitable candidates for …

Electrospinning Piezoelectric Fibers For Biocompatible Devices, Bahareh Azimi, Mario Milazzo, Andrea Lazzeri, Stefano Berrettini, M. Jasim Uddin, Zhao Qin, Markus J. Buehler, Serena Danti

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

The field of nanotechnology has been gaining great success due to its potential in developing new generations of nanoscale materials with unprecedented properties and enhanced biological responses. This is particularly exciting using nanofibers, as their mechanical and topographic characteristics can approach those found in naturally occurring biological materials. Electrospinning is a key technique to manufacture ultrafine fibers and fiber meshes with multifunctional features, such as piezoelectricity, to be available on a smaller length scale, thus comparable to subcellular scale, which makes their use increasingly appealing for biomedical applications. These include biocompatible fiber-based devices as smart scaffolds, biosensors, energy harvesters, and …

On Comparison Of Luminescence Properties Of La2zr2o7 And La2hf2o7 Nanoparticles, Santosh K. Gupta, Maya Abdou, Partha Sarathi Ghosh, Jose P. Zuniga, Ezhilarasan Manoharan, Hyeongjun Kim, Yuanbing Mao

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

Unveiling the underlying mechanisms of properties of functional materials, including the luminescence differences among similar pyrochlores A2B2O7, opens new gateways to select proper hosts for various optoelectronic applications by scientists and engineers. For example, although La2Zr2O7 (LZO) and La2Hf2O7 (LHO) pyrochlores have similar chemical compositional and crystallographic structural features, they demonstrate different luminescence properties both before and after doped with Eu3+ ions. Based on our earlier work, LHO‐based nanophosphors display higher photo‐ and radioluminescence intensity, higher quantum efficiency, and longer excited state lifetime compared to LZO‐based nanophosphors. Moreover, under electronic O2−→Zr4+/Hf4+ transition excitation at 306 nm, undoped LHO nanoparticles (NPs) …

Td-Dft Spin-Adiabats With Analytic Nonadiabatic Derivative Couplings, Nicole Bellonzi, Ethan Alguire, Shervin Fatehi, Yihan Shao, Joseph E. Subotnik

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

Wepresent an algorithm for efficient calculation of analytic nonadiabatic derivative couplings between spin-adiabatic, time-dependent density functional theory states within the Tamm-Dancoff approximation. Our derivation is based on the direct differentiation of the Kohn-Sham pseudowavefunction using the framework of Ou et al. Our implementation is limited to the case of a system with an even number of electrons in a closed shell ground state, and we validate our algorithm against finite difference at an S1/T2 crossing of benzaldehyde. Through the introduction of a magnetic field spin-coupling operator, we break time-reversal symmetry to generate complex valued nonadiabatic derivative couplings. Although the nonadiabatic …

Lanthanide-Doped Lanthanum Hafnate Nanoparticles As Multicolor Phosphors For Warm White Lighting And Scintillators, Santosh K. Gupta, Jose P. Zuniga, Maya Abdou, Melonie P. Thomas, Manisha De Alwis Goonatilleke, Beth S. Guiton, Yuanbing Mao

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

Designing luminescent materials especially nanomaterials with multifunctional applications is highly challenging and demanding. In this work, we explored pyrochlore La2Hf2O7 nanoparticles (NPs) singly and triply codoped with Eu3+, Tb3+ and Dy3+. Under both ultraviolet and X-ray irradiations, the La2Hf2O7 NPs singly doped with Eu3+, Tb3+ and Dy3+ displayed red, green and yellowish-blue emission, respectively. The concentration quenching study revealed a non-radiative energy transfer in Eu3+ doped La2Hf2O7 NPs, which takes place via dipole-quadrupole mechanism. On the other hand, a dipole-dipole interaction prevails in Tb3+ and Dy3+ doped La2Hf2O7 NPs. Lifetime spectroscopy reveals the stabilization of Eu3+ and Dy3+ ions at …

Tailoring The Viscosity Of Water And Ethylene Glycol Based Tio2 Nanofluids, Abu Musa Abdullah, Aminur Rashid Chowdhury, Yingchen Yang, Horacio Vasquez, Justin Moore, Jason Parsons, Karen Lozano, Jose J. Gutierrez, Karen S. Martirosyan, Mohammed Uddin

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

Highlights

• Viscosity of TiO2 nanofluid at variable physical parameters has been reviewed.

• Classical and experimental viscosity models of nanofluids have been discussed.

• Preparation techniques of TiO2 nanofluid have been discussed.

• Viscosity of TiO2 nanofluid can increase by 329 times compared to the base fluid.

• Viscosity of TiO2 nanofluid decreases significantly with increasing temperature.

Abstract

Nanofluids have garnered significant attention in the scientific and engineering research communities due to their enhanced heat transfer properties when compared to conventional thermal fluids. Nanofluids comprised of titanium dioxide (TiO2) nanoparticles have a wide range of applications due to their excellent thermophysical properties like thermal …

Lysyl-Trna Synthetase From Pseudomonas Aeruginosa: Characterization And Identification Of Inhibitory Compounds, Samantha Balboa, Yanmei Hu, Frank B. Dean, James M. Bullard

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

Pseudomonas aeruginosa is an opportunistic pathogen that causes nosocomial infections and has highly developed systems for acquiring resistance against numerous antibiotics. The gene (lysS) encoding P. aeruginosa lysyl-tRNA synthetase (LysRS) was cloned and overexpressed, and the resulting protein was purified to 98% homogeneity. LysRS was kinetically evaluated, and the Km values for the interaction with lysine, adenosine triphosphate (ATP), and tRNALys were determined to be 45.5, 627, and 3.3 µM, respectively. The kcatobs values were calculated to be 13, 22.8, and 0.35 s−1, resulting in kcatobs/KM values of 0.29, 0.036, and 0.11 s−1µM−1, …

Stabilization Dynamics Of The Ozone Molecular System, Sangeeta Sur

Doctoral Dissertations

"The observation of larger-than-expected concentrations of heavier isotopologues of ozone known as 'ozone isotopic anomaly' in the stratosphere is a mass-independent effect (in contrast to most kinetic isotope effects familiar to chemists) that is traced back to the recombination process in the formation of ozone in the Chapman cycle. Understanding the relative efficiencies (often approximated as equal for different isotopologues) of the stabilization step (some of the details of which are still a mystery) which involves energy transfer from a highly excited ozone molecule to a third body, M (argon atom in this case) to form stable ozone is a …

Multimodal Vibrational Studies Of Drug Uptake In Vitro: Is The Whole Greater Than The Sum Of Their Parts?, David Perezguaita, Karolina Chrabaszcz, Kamilla Malek, Hugh Byrne

Articles

Herein, we investigated the use of multimodal Raman and infrared (IR) spectroscopic microscopy for the elucidation of drug uptake and subsequent cellular responses. Firstly, we compared different methods for the analysis of the combined data. Secondly, we evaluated whether the combined analysis provided enough benefits to justify the fusion of the data. A459 cells inoculated with doxorubicin (DOX) at different times were fixed and analysed using each technique. Raman spectroscopy provided high sensitivity to DOX and enabled an accurate estimation of the drug uptake at each time point, whereas IR provided a better insight into the resultant changes in the …

Quantification Of Low-Content Encapsulated Active Cosmetic Ingredients In Complex Semi-Solid Formulations By Means Of Attenuated Total Reflectance-Infrared Spectroscopy, Franck Bonnier, Lynda Miloudi, Sandra Henry, Dominique Bertrand, Clovis Tauber, Xavier Perse, Florent Yvergnaux, Hugh Byrne, Igor Chourpa, Emilie Munnier

Articles

Attenuated total reflectance-infrared (ATR-IR) spectroscopy is a robust tool for molecular characterisation of matter. Applied to semi-solid formulations, it enables rapid and reliable data collection without pre-analytical requirements. Based on nano-encapsulated Omegalight®, a skin-lightening active cosmetic ingredient (ACI), incorporated in a hydrogel, it is first demonstrated that, despite the high water content and the chemical complexity of the samples (i.e. number of ingredients), the spectral features of the ACI can be detected and monitored. Secondly, with a total of 105 samples divided into a training set (n = 60) and an unknown set (n = 45) covering a …

Raman Mapping Coupled To Self Modelling Mcr-Als Analysis To Estimate Active Cosmetic Ingredient Penetration Profile In Skin, Aline Stella, Franck Bonnier, Ali Tfayli, Florent Yvergnaux, Hugh Byrne, Igor Chourpa, Emilie Munnier, Clovis Tauber

Articles

Confocal Raman mapping (CRM) is a powerful, label free, non-destructive tool, enabling molecular characterization of human skin with applications in the dermo-cosmetic field. Coupling CRM to multivariate analysis can be used to monitor the penetration and permeation of active cosmetic ingredients (ACI) after topical application. It is presently illustrated how multivariate curve resolution alternating least squares (MCR-ALS) can be applied to detect and semi-quantitatively describe the diffusion profile of Delipidol, a commercially available slimming ACI, from Raman spectral maps. Although the analysis outcome can be critically dependent on the a priori selection of the number of regression components, it is …

Exploiting Fourier Transform Infrared And Raman Microspectroscopies On Cancer Stem Cells From Oral Squamous Cells Carcinoma: New Evidence Of Acquired Csplatin Chemoresistance, Valentina Notarstefano, Simona Sabbatini, Chiaro Pro, Alessia Belloni, Giulia Orilisi, Corrado Rubini, Hugh Byrne, Lisa Vaccari, Elisabetta Giorgini

Articles

Oral Squamous Cells Carcinoma (OSCC) is characterised by the risk of recurrence and the onset of a refractoriness response to chemotherapy drugs. These phenomena have been recently related to a subpopulation of Cancer Stem Cells (CSCs), which have either an innate or acquired drug resistance, triggered by chemotherapy treatments. In this light, to precisely target chemotherapy regimens, it is essential to improve knowledge on CSCs, with a particular focus on their molecular features. In this work, a subpopulation of CSCs, isolated by tumour sphere formation from primary OSCC cells, were treated with cisplatin for 16, 24 and 48 hours and …

Microplastic Fragment And Fiber Contamination Of Beach Sediments From Selected Sites In Virginia And North Carolina, Usa, Gabrielle Z. Dodson, A. Katrina Shotorban, Patrick G. Hatcher, Derek Waggoner, Sutapa Ghosal, Nora Noffke

OES Faculty Publications

Microplastic particles (<5 >mm) constitute a growing pollution problem within coastal environments. This study investigated the microplastic presence of estuarine and barrier island beaches in the states of Virginia and North Carolina, USA. Seventeen sediment cores were collected at four study sites and initially tested for microplastic presence by pyrolysis-gas chromatography–mass spectrometry. For the extraction, microplastic particles were first separated from the sediment using a high-density cesium chloride solution (1.88 g/mL). In a second step, an oil extraction collected the remaining microplastic particles of higher densities. Under the light microscope, the extracted microplastic particles were classified based on their morphologies …

Synthesis And Design Of Novel Polymer Grafted Nanoparticles Relevant To Drug Delivery Vehicles For Biomedical Application, Maan Abduldiyem Hassan Al-Ali

Theses and Dissertations

The modification of inorganic nanoparticles with organic polymer chains has become a significant field of study for the engineering of advanced nanocomposite materials. This dissertation presents the design, synthesis, and characterization of novel polymer grafted silica nanoparticles as new strategies to combat bacterial resistance. Described herein is the synthesis of monomers that have been graft polymerized onto silica nanoparticles that can be used as a delivery drug vehicle for biomedical applications. The polymerization of these monomers was performed via reversible addition-fragmentation chain transfer (RAFT) polymerization. The molecular design of the RAFT agents that are attached to the surfaces of the …

Metal Ions Impact On Shewanella Oneidensis Mr-1 Adhesion To Ito Electrode And The Enhancement Of Current Output, Aisha Awad Alshahrani

Dissertations

The goal of this study is to enhance the efficiency of bacterial extracellular electron transfer (EET) in Shewanella oneidensis MR-1 by enhancing adhesion to the electrode's surface. Our results clearly show a major difference in the attachment and behavior of Shewanella oneidensis MR-1 for Ca2+, Pb2+, Cd2+, and Mg2+, compared to the control. the final microbial coverage, as measured by confocal microscopy and cathodic peak charge in cyclic voltammetry (Qpc), increases with increasing metal ion concentrations. We found the cells attached to the electrode increased more with the addition of metal ion concentrations in the following order of metals: Ca2+ …

Optimization Of Microbial Fuel Cells, Norberto M. Gonzalez

Dissertations

Optimization of microbial fuel cells is investigated by utilizing Shewanella oneidensis as a model microorganism. the microbe's ability to grow and use glucose as a carbon source is explored under varying oxygen environments through an offline PMP derivatization method and HPLC analysis. Shewanella growth and glucose utilization is enhanced under aerobic environments; however, under microaerobic environments the addition of ferric iron results in a faster exponential growth initialization. a flavin mononucleotide modified indium tin oxide electrode is prepared and characterized for its usefulness in microbial fuel cells by controlled potential electrolysis, cyclic voltammetry, and electrochemical impedance spectroscopy studies. the electrode …

Lewis Acid-Carbonyl Solution Interactions And Their Implications In Catalytic Systems, Carly Soren Hanson

Dissertations

The utilization of Lewis acids to activate substrates containing carbonyls is ubiquitous in organic synthetic methods. in order to facilitate the development of novel reaction pathways and understand existing methods, it is necessary to determine the solution interactions between Lewis acids and Lewis bases. Historically, the characterization of the interactions of Lewis pairs has relied on solid state infrared (IR) spectroscopy and X-ray crystallography, as well as in situ NMR. I have developed a method utilizing in situ IR spectroscopy and solution conductivity towards the identification of the solution structures formed when a range of carbonyl compounds are combined with …

Development Of Methods For The Removal Of Selected Pollutants From Several Matrices And Identification Of Unknown Pollutants Adsorbed Onto Plastics Collected From Freshwater, Kathryn Marie Renyer

Dissertations

Plastic pollution represents one of greatest anthropogenic threats to the environment. Five to ten billion tons of plastic are manufactured every year. Currently, Earth's ecosystem is contaminated with billions of tons of plastic debris, much of which cannot be recycled. Over time, this plastic debris decomposes into small particles. Small plastic particles are known to adsorb toxic compounds in marine environments. My research is concerned with creating novel methods for the detection and quantification of selected persistent organic pollutants from several media. Specifically, I developed methods for the detection and quantification of endosulfan sulfate (ESS) from Lumbricus terrestris tissue and …

Electron Transfer Of Shewanella Oneidensis Mr-1 At Clay-Modified Ito Electrode, Reem Faez Alshehri

Dissertations

Various strategies have been established to enhance the extracellular electron transfer and energy output capability of microbial fuel cells, with the majority being aimed at anode modification. The anode has a significant impact on the electricity generation performance of MFCs because it is in direct contact with the microorganisms. The materials of the anode should be favorable for the bacterial cell and capable to facilitate the electron transfer. Developing of an electrode using low-cost and effective materials assists to enhance the bacterial cell attachment and extracellular electron transfer. This provides a significant improvement in MFC performance. In this study, clay …

Benzimidazole Containing Acetamide Derivatives Attenuate Neuroinflammation And Oxidative Stress In Ethanol-Induced Neurodegeneration, Muhammad Imran, Lina Tariq Al Kury, Humaira Nadeem, Fawad Ali Shah, Muzaffar Abbas, Shagufta Naz, Arif Ullah Khan, Shupeng Li

All Works

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. Oxidative stress-induced neuroinflammation is the prominent feature of neurodegenerative disorders, and is characterized by a gradual decline of structure and function of neurons. Many biochemical events emerge thanks to the result of this neurodegeneration, and ultimately provoke neuroinflammation, activation of microglia, and oxidative stress, leading to neuronal death. This cascade not only explains the complexity of events taking place across different stages, but also depicts the need for more effective therapeutic agents. The present study was designed to investigate the neuroprotective effects of newly synthesized benzimidazole containing acetamide derivatives, 3a (2-(4-methoxyanilino)-N-[1-(4-methylbenzene-1-sulfonyl)-1H-benzimidazol-2-yl] …

Deriving Statistical Inference From The Application Of Artificial Neural Networks To Clinical Metabolomics Data, Kevin M. Mendez

Theses: Doctorates and Masters

Metabolomics data are complex with a high degree of multicollinearity. As such, multivariate linear projection methods, such as partial least squares discriminant analysis (PLS-DA) have become standard. Non-linear projections methods, typified by Artificial Neural Networks (ANNs) may be more appropriate to model potential nonlinear latent covariance; however, they are not widely used due to difficulty in deriving statistical inference, and thus biological interpretation. Herein, we illustrate the utility of ANNs for clinical metabolomics using publicly available data sets and develop an open framework for deriving and visualising statistical inference from ANNs equivalent to standard PLS-DA methods.

Adiabatic Trajectory Approximation Within The Framework Of Mixed Quantum/Classical Theory, Bikramaditya Mandal, Alexander Semenov, Dmitri Babikov

Chemistry Faculty Research and Publications

A hierarchy of approximate methods is proposed for solving the equations of motion within a framework of the mixed quantum/classical theory (MQCT) of inelastic molecular collisions. Of particular interest is a limiting case: the method in which the classical-like equations of motion for the translational degrees of freedom (scattering) are decoupled from the quantum-like equations for time evolution of the internal molecular states (rotational and vibrational). In practice, trajectories are pre-computed during the first step of calculations with driving forces determined solely by the potential energy surface of the entrance channel, which is an adiabatic trajectory approximation. Quantum state-to-state transition …

Surface-Enhanced Raman Scattering For Enantiomeric Discrimination, Thanyada Sukmanee

Chulalongkorn University Theses and Dissertations (Chula ETD)

Surface-enhanced Raman scattering (SERS) substrates with intended surface modification were developed for enantiomeric analysis by taking the consideration of asymmetric electric field and molecular interaction between a probe molecule and enantiomeric analyte. In the first study, discrimination between enantiomers is achieved by performing tip-enhanced Raman scattering using a silver tip which is chemically modified by an achiral para-mercaptopyridine (pMPY) probe molecule. The different relative intensities of the pMPY spectra were obtained when three pairs of enantiomers containing hydroxy and/or amino groups were used as analytes. Enantiomeric discrimination can be attained by the asymmetric electric field of the tip apex co-existed …

Electrospun Polyacrylonitrile/Graphene Oxide Nanofibers As Sorbent For Solid Phase Extraction Of Epichlorohydrin In Water, Chotitas Sribun

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this study, electrospun nanofibers of polyacrylonitrile functionalized with graphene oxide (PAN/GO) were fabricated and applied as a sorbent in solid phase extraction in a disk format (SPE disk). Graphene oxide were synthesized by chemical oxidation of graphite powder via Hummers and Tour methods and were characterized by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). For electrospun PAN/GO nanofibers, the average diameters of fibers ranged from 117-147 nm and the surface area of PAN and PAN/GO nanofibers were ranged from 7.77-13.40 m2/g. Then, the PAN/GO nanofibers were assembled in a SPE disk format and …

Development Of Polymeric Niosomes Containing Oxyresveratrol For Skin Care Products, Jirawut Jaimun

Chulalongkorn University Theses and Dissertations (Chula ETD)

Designing delivery systems to improve active ingredient (AI) efficiencies have increased incredible interests in recent years. In this study, a vesicular system has been developed using thin film hydration method with modifications. Niosomes formed from sorbitan monoesters (SpanTM) with cholesterol molar ratios of 0, 0.5, 1 and 1.5 were prepared with varying AI amount 10-50 mg and was hydrated by hyaluronan solution. Oxyresveratrol was separated from the heartwoods of Artocarpus lacucha. This AI has been broadly utilized to restrain enzyme tyrosinase; however, it possesses low stability against heat and light. Encapsulation utilizing niosome or polymeric niosome as a delivery system …

การออกแบบและการประเมินกระบวนการของระบบเซลล์เชื้อเพลิงชนิดคาร์บอเนตหลอมเหลวร่วมกับระบบการแยกอากาศด้วยเคมิคอลลูปปิง, กวินทรา กอบกู้วิทยา

Chulalongkorn University Theses and Dissertations (Chula ETD)

เซลล์เชื้อเพลิงชนิดคาร์บอเนตหลอมเหลวเป็นอุปกรณ์ผลิตไฟฟ้าผ่านกระบวนการทางไฟฟ้าเคมีที่มีประสิทธิภาพสูงและปล่อยมลพิษต่ำ อย่างไรก็ตามการใช้ไฮโดรคาร์บอนเป็นเชื้อเพลิงยังคงมีการปลดปล่อยคาร์บอนไดออกไซด์สู่บรรยากาศ งานวิจัยนี้จึงมีแนวคิดที่จะพัฒนาระบบเซลล์เชื้อเพลิงชนิดคาร์บอเนตหลอมเหลวร่วมกับการดักจับคาร์บอนไดออกไซด์โดยใช้กระบวนการแยกอากาศด้วยเคมิคอลลูปปิง โดยการสร้างแบบจำลองของระบบเซลล์เชื้อเพลิงร่วมกับระบบการแยกอากาศด้วยกระบวนเคมิคอลลูปปิงด้วยโปรแกรม Aspen plus ในแบบจำลองใช้ดีเซลเป็นเชื้อเพลิงและแมงกานีสออกไซด์เป็นตัวพาออกซิเจน แบ่งการออกเป็น 2 กรณี คือ กรณีที่ใช้คาร์บอนไดออกไซด์และกรณีที่ใช้ไอน้ำเป็นตัวพาออกซิเจน จากผลการศึกษา พบว่า ระบบที่มีการดักจับคาร์บอนไดออกไซด์ให้ประสิทธิภาพการผลิตไฟฟ้าโดยรวมต่ำกว่าระบบที่ไม่มีการดักจับคาร์บอนไดออกไซด์ แต่สามารถดักจับคาร์บอนไดออกไซด์ได้สูงถึงร้อยละ 81.13 เมื่อเปรียบเทียบกรณีที่ใช้แก๊สตัวพาออกซิเจนต่างกัน พบว่า กรณีที่ใช้คาร์บอนไดออกไซด์ให้ประสิทธิภาพการผลิตไฟฟ้าสูงกว่ากรณีที่ใช้ไอน้ำโดยให้ค่าประสิทธิภาพ การผลิตไฟฟ้าโดยรวมเท่ากับร้อยละ 50.78 และ 50.03 ตามลำดับ นอกจากนี้ พบว่า กรณีที่ใช้คาร์บอนไดออกไซด์มีปริมาณการปล่อยคาร์บอนไดออกไซด์และดัชนีการใช้พลังงานต่อการดักจับคาร์บอนไดออกไซด์ต่ำกว่ากรณีที่ใช้ไอน้ำ ซึ่งมีค่า 2.72 และ 2.76 โมลต่อกิโลวัตต์ชั่วโมง และ 109.27 และ 120.84 กิโลจูลต่อโมลคาร์บอนไดออกไซด์ ตามลำดับ นอกจากนี้จากการศึกษาผลของตัวแปรดำเนินการต่างๆ ที่ส่งผลต่อประสิทธิภาพการผลิตไฟฟ้าและความสามารถในการดักจับคาร์บอนไดออกไซด์ พบว่า ภาวะดำเนินการที่ดีที่สุด ได้แก่ อัตราส่วนต่อไอน้ำเท่ากับ 3 อุณหภูมิรีฟอร์มิงเท่ากับ 800 องศาเซลเซียส อุณหภูมิดำเนินการของเซลล์เชื้อเพลิงเท่ากับ 750 องศาเซลเซียส สัดส่วนการใช้เชื้อเพลิงเท่ากับร้อยละ 79 และสัดส่วนการใช้คาร์บอนไดออกไซด์เท่ากับร้อยละ 65 โดยให้ประสิทธิภาพการผลิตไฟฟ้าโดยรวมและดัชนีการใช้พลังงานต่อการดักจับคาร์บอนไดออกไซด์เท่ากับร้อยละ 53.04 และ 122.12 กิโลจูลต่อโมลคาร์บอนไดออกไซด์

ผลของอายุคอมพาวนด์ต่อยางไม่ผ่านมาตรฐานจากเครื่องอัดรีดแบบสี่หัวและสมบัติของหน้ายาง, ปิยธิดา จันทรางสุวรรณ์

Chulalongkorn University Theses and Dissertations (Chula ETD)

การเติบโตของอุตสาหกรรมยานยนต์ส่งผลต่อการผลิตยางล้อ ยางคอมพาวนด์ จำนวนมาก ถูกทำลายจากการผลิตที่มากเกินไป เนื่องจากยางคอมพาวนด์ที่ถูกจัดเก็บ เป็นเวลานานอาจส่งผลต่อคุณภาพของยางรถยนต์ งานวิจัยชิ้นนี้ศึกษาผลกระทบของ ระยะเวลาการจัดเก็บยางคอมพาวนด์ที่อุณหภูมิ 25 °C เป็นเวลา 30 วัน และ 50 °C เป็นเวลา 6 วัน ยางคอมพาวนด์ถูกแบ่งประเภทโดยสารตัวเติมได้แก่ เขม่าดำ ซิลิกา – เขม่าดำที่อัตราส่วนโดยน้ำหนักเท่ากับ 1.3 และ 5.8 ทุกๆ 3 วันยางคอมพาวนด์ ถูกวิเคราะห์ผ่านเครื่องวัดความหนืดมูนนี่ และเครื่อง MDR รวมไปถึงการทดสอบ ค่าความแข็ง ความกระเด้งกระดอน สมบัติแรงดึง ความหนาแน่นของการเชื่อมขวาง และสัดส่วนเจลในยางวัลคาไนซ์ จากผลการศึกษา การเชื่อมขวางในตัวยางคอมพาวนด์ จะมีปริมาณมากขึ้นตามเวลา ส่งผลให้ค่าความหนืดมูนนี่มีปริมาณเพิ่มขึ้น โดยยางคอมพาวนด์ที่ใช้ซิลิกามีหมู่ไซลานอล (Si-OH) ที่พื้นผิวจะเกิดปฏิกิริยา ระหว่างสารตัวเติมมากกว่าเขม่าดำ การเพิ่มอุณหภูมิในการจัดเก็บยางคอมพาวนด์ส่งผลให้ เร่งการเกิดการเชื่อมขวาง สำหรับพฤติกรรมการคงรูป การเชื่อมขวางที่เพิ่มขึ้น ส่งผลให้ระยะเวลาการสุกลดลง ค่าแรงบิดต่ำสุดมีค่าเพิ่มขึ้น และค่าแรงบิดสูงสุดลดลง สำหรับยางวัลคาไนซ์ การเชื่อมขวางเพิ่มขึ้นส่งผลต่อการเพิ่มขึ้นของค่าความแข็ง ความกระเด้งกระดอน ยางจะมีความแข็งแรงและเหนียวที่มากขึ้น โดยยางคอมพาวนด์ ที่ถูกจัดเก็บที่ 50 °C จะมีระยะเวลาการจัดเก็บไม่เกิน 3 วัน

Regenerated Amorphous Cellulose From Pineapple Leaf Fibers Via Sulfuric Acid Treatment, Gisma Coraima Asmarani

Chulalongkorn University Theses and Dissertations (Chula ETD)

Pineapple leaf fiber (PALF) is an agricultural residue available abundantly in Thailand as a renewable resource with high cellulose content. In this research, a simple process using sulfuric acid (H2SO4) treatment has been developed to produce three types of cellulosic products from PALF, which are regenerated amorphous (RAC), microcrystalline (MCC), and nanocrystalline (NCC) cellulose. H2SO4 acid treatment has been done in 25% and 50% (v/v) H2SO4 under three different temperatures (-20, 30, and 50 ºC). In 25% (v/v) H2SO4, various MCC lengths (about 29.57 ± 9.99 to 106.40 ± 61.10 μm) were produced from different temperatures. Different temperatures in this …

Electrocoagulation In Two Phase Separation For Manipulation Of Volatile Compound Profiles In Perfumes, Isaya Thaveesangsakulthai

Chulalongkorn University Theses and Dissertations (Chula ETD)

Electrocoagulation (EC) approach employing two aluminium electrodes and a two phase medium of aqueous solution of NaCl and hexane (2-phase-EC) was developed. The approach enabled electrochemical treatment of odor active compounds in perfume extract. The samples before and after 2-phase-EC at cathode, anode and between the two electrodes left for equilibrium after the treatment were analyzed by using solid phase micro extraction (SPME) and gas chromatography hyphenated with mass spectrometry (GC-MS). This allowed identification of volatile compounds in each sample based on comparison with MS and retention index database. After the treatment, the perfume smells were fresher, sweeter and more …