Chemistry Commons^™

Transition State Theory Application To H2 Gas Sensitivity Of Pristine And Pd Doped Sno2 Clusters, Mudar Ahmed Abdulsattar

Karbala International Journal of Modern Science

The reaction of H₂ and O₂ gases with pristine and Pd doped Sn₁₀O₁₆ clusters is investigated using transition state theory and density functional theory. The reaction of hydrogen and oxygen molecules is controlled by a transition state that implies crossing an activation energy hill to react with the SnO₂ cluster. Our investigation performs thermodynamic calculations, including Gibbs free energy, enthalpy, and entropy of activation and reaction in the temperature range 25-500 °C. The results show that the Gibbs free energy of activation of H₂ gas reaction is 0.23 and 0.18 eV for pristine …

On The Dynamic Behaviour Of Automobile Pulleys Under Cyclic Loading, Haval Kamal Asker, Thaker Saleh Dawood

Karbala International Journal of Modern Science

This paper investigates the dynamic characteristics of pulley systems with different numbers of bolt holes. Models with four, six and eight bolt holes were chosen for the pulley. Three sets of cyclic pressure were applied to the pulley system to resemble the different running revolutions of an engine. The study investigates the effect of the number of holes on the system’s stiffness and natural frequency. Finite element models were used to simulate the obtained deformations, stresses and frequency response function (FRF) for pulley models comprising four, six and eight bolt holes under different cyclic pressures. The results show that the …

Optically Thick Radiating Free Convective Mhd Nanofluid Flow Over An Exponentially Accelerated Plate, D.P. Bhatta, S.R. Mishra, J.K. Dash

Karbala International Journal of Modern Science

The present analysis investigates an unsteady conducting water-based nanofluid embedding with porous medium over an exponentially accelerated vertical plate. The plate is accelerated with moving ramped temperature. However, water is treated as the base fluid with Copper (Cu) and Titanium Oxide (TiO₂) as nanoparticles. Effects of thermal radiation, heat source, and radiation absorption are taken care of in the energy equation which may enhance the heat transfer properties of nanofluid. The crux of the investigation is to find the closed-form solution of nonlinear coupled partial differential equations. Laplace Transform technique is employed to solve these equations. The influence …

A Support Vector Machine-Based Prediction Model For Electrochemical Machining Process, Subham Agarwal Mr., Shruti Sudhakar Dandge Ms., Shankar Chakraborty Prof.

Karbala International Journal of Modern Science

Manufacturing of quality products is one of the core measures to address competitiveness in industries. Hence, it is always necessary to accomplish quality prediction at early stages of a manufacturing process to attain high quality products at the minimum possible cost. To achieve this goal, the past researchers have developed and investigated the applications of different intelligent techniques for their effective deployment at various stages of manufacturing processes. In this paper, support vector machine (SVM), a supervised learning system based on a novel artificial intelligence paradigm, is employed for prediction of three responses, like material removal rate, surface roughness and …

Influence Of Carbon Fibres On Strain Sensing And Structural Properties Of Rc Beams Without Stirrups, Arvind Kumar Cholker, Manzoor Ahmad Tantray

Karbala International Journal of Modern Science

In present study, effect of micro carbon fibres on strain sensing property and structural behavior of the reinforced concrete (RC) beams in absence of stirrups was experimentally investigated. A total of three RC beams of dimensions, 125 mm width, 350 mm height and 1500 mm long were manufactured without stirrups. All the three beams had different longitudinal reinforcement ratios (0.9%, 1.43% and 1.03 %) and uniform strength of concrete of 36.5 MPa. All the beams had carbon fibre based concrete (CFBC) at top and bottom surface in mid span for a length of 350mm and depth of 78 mm. All …

Approximating Fixed Points In Modular Spaces, Salwa Salman Abed, Meena Fouad Abduljabbar

Karbala International Journal of Modern Science

A generic two theorems for the two step iterative sequence of multivalued mappings are proved in a complete convex real modular space, and then cite some corollaries that are special cases of these theorems.

Editorial Board

Karbala International Journal of Modern Science

No abstract provided.

Investigating Geochemical Processes Of Fluid-Rock Interactions On Materials Related To Energy And Environment, Zelong Zhang

LSU Doctoral Dissertations

Understanding the potential processes of radionuclides released from nuclear waste forms is essential to the safe disposal and containment of nuclear waste. Iodoapatite, a potential waste form for radioiodine, was chosen as a model system to examine the impact by common aqueous anions on iodine release processes. Four semi-dynamic leaching tests were performed using 0.1 mol/L NaCl, Na₂CO₃, Na₃PO₄, and Na₂SO₄ solutions respectively under 90 °C, 1 bar, fixed S/V ratio 5/m (sample surface area to solution volume), and with 24-hour replacement of the leaching solutions. Solution analysis and …

Novel Reusable Renewable Resource-Based Benign Nanocomposites For Removal And Recovery Of Phosphorus From Contaminated Water, Amita Nakarmi

Theses and Dissertations

Phosphorus (P) is a pollutant which degrades water quality and is a cause of concern for eutrophication of water. This research dissertation discusses the synthesis of novel, renewable resource-based, single metallic and bimetallic nanocomposite media, their use in Phosphorus remediation as phosphate, and their regeneration for reuse. The media consist of chemically modified pine wood chips in addition to metal oxides/hydroxides. Iron is used for single metallic media, while cerium/aluminum and cerium/manganese are used for mixed bimetallic media. The synthetic method is environmentally friendly and economically viable. These nanocomposites may find use in the removal of P from contaminated waters, …

Benzosiloles With Crystallization-Induced Emission Enhancement Of Electrochemiluminescence: Synthesis, Electrochemistry, And Crystallography, Liuqing Yang, Donghyun Koo, Jackie Wu, Jonathan M. Wong, Tyler Day, Ruizhong Zhang, Harshana Kolongoda, Kehan Liu, Jian Wang, Zhifeng Ding, Brian Pagenkopf

Chemistry Publications

Crystallization-induced emission enhancement (CIEE) was demonstrated for the first time for electrochemilunimescence (ECL) with two new benzosiloles. Compared with their solution, the films of the two benzosiloles gave CIEE of 24 times and 16 times. The mechanism of the CIEE-ECL was examined by spooling ECL spectroscopy, X-ray crystal structure analysis, photoluminescence, and DFT calculation. This CIEE-ECL system is a complement to the well-established aggregation-induced emission enhancement (AIEE) systems. Unique intermolecular interactions are noted in the crystalline chromophore. The first heterogeneous ECL system is established for organic compounds with highly hydrophobic properties.

Fabrication, Characterization And Applications Of Chemically Modified Planar Metallic Electrodes From Copper Clad Sheets, Rana T. Alsaidi

Theses

In this work, we developed a fabricating method for planar electrodes by milling and cutting copper-clad sheets. The main objectives of this thesis are to produce customized planar electrodes with different geometries with relatively higher reusability compared to the screen-printed electrodes available by commercial vendors. The fabricated electrodes from copper-clad sheets were electroplated with different metals using commercial electroplating baths to produce different metallic planar electrodes. Also, the fabrication of planar electrodes with cavities to be filled with modified carbon paste was done. The electroplated planar electrodes were characterized by the cyclic voltammetry technique. In addition to that, they were …

Thermodynamic Characterization Of Free And Surface Water Of Colloidal Unimolecular Polymer (Cup) Particles Utilizing Dsc, Peng Geng, Ashish Zore, Michael R. Van De Mark

Chemistry Faculty Research & Creative Works

Colloidal Unimolecular Polymer (CUP) particles are spheroidal, 3-9 nm with charged groups on the surface and a hydrophobic core, which offer a larger surface water fraction to improve the analysis of its characteristics. Differential scanning calorimetry (DSC) was performed to determine the characteristics of surface water. These properties include the amount of surface water, the layer thickness, density, specific heat of the surface water above and below the freezing point of water, melting point depression of free water, effect of charge density and particle size. The charge density on the CUP surface was varied as well as the molecular weight …

An International Laboratory Comparison Of Dissolved Organic Matter Composition By High Resolution Mass Spectrometry: Are We Getting The Same Answer?, Jeffrey A. Hawkes, Juliana D'Andrilli, Jeffrey N. Agar, Mark P. Barrow, Stephanie M. Berg, Núria Catalán, Hongmei Chen, Rosalie K. Chu, Richard B. Cole, Thorsten Dittmar, Rémy Gavard, Gerd Gleixner, Patrick G. Hatcher, Chen He, Nancy J. Hess, Ryan H.S. Hutchins, Amna Ijaz, Hugh E. Jones, William Kew, Maryam Khaksari, Diana Catalina Palacio Lozano, Jitao Lv, Lynn Mazzoleni, Beatriz E. Noriega-Ortega, Helena Osterholz, Nikola Radoman, Shuzhen Zhang, Phoebe Zito, David C. Podgorski

Michigan Tech Publications, Part 1

High-resolution mass spectrometry (HRMS) has become a vital tool for dissolved organic matter (DOM) characterization. The upward trend in HRMS analysis of DOM presents challenges in data comparison and interpretation among laboratories operating instruments with differing performance and user operating conditions. It is therefore essential that the community establishes metric ranges and compositional trends for data comparison with reference samples so that data can be robustly compared among research groups. To this end, four identically prepared DOM samples were each measured by 16 laboratories, using 17 commercially purchased instruments, using positive-ion and negative-ion mode electrospray ionization (ESI) HRMS analyses. The …

Altering An Epoxy-Amine Thermoset's Performance Through Varying Mix Ratios, Kiersten M. Smith

Master's Theses

Epoxy resins are used in a number of different industries and therefore have application-specific material requirements, from satellites that require materials that operate in space, to paints and coatings that require high scratch resistance and mechanical durability, to medical devices, designed to be in continuous contact with biological fluids. Commercial epoxy products come with manufacturer’s information explaining the epoxy properties and recommended preparation processing conditions, which may include epoxy resin to curing agent mix ratio (Part A : Part B), cure time, and cure temperature, for example. Due to proprietary reasons, it can be difficult to understand why these values …

Pitting Corrosion Of Oerlikon’S Abrasion Resistant Ferritic Stainless Steels, Matthew P. Nalty, Emma Wagstaff

Materials Engineering

Existing hardfacing coatings for hydraulic cylinders and brake disc applications crack during use leaving the components susceptible to corrosion. To address this problem, Oerlikon has designed three new alloys to be abrasion and corrosion resistant. This paper reviews the literature necessary to understand and quantify pitting resistance of stainless-steel alloys. It documents one round of testing ASTM G48 method A: Ferric Chloride Pitting Test of Stainless Steels on the new alloys P72-X9, P72-X13, P129-X9, as well as samples of 431, 316, and 2205 stainless steels. This paper also discusses improvements to the G48 testing method and industry use of the …

The Reduction, Sequestration, And/Or Coordination Of Technetium-99 Utilizing Polyoxometalates And Nanomaterials, Colleen Mb Gallagher

Dissertations, Theses, and Capstone Projects

Research into the sequestration of radionuclides from aqueous media is being conducted due to the contamination of aqueous waste effluents and groundwater with highly toxic long-lived radionuclides. These contaminants are introduced into water and streams from legacy nuclear sites, nuclear reactor operations, nuclear fuel reprocessing, nuclear weapons testing, and plutonium production. A major contributor (~6%) to the waste from thermal neutron fission of uranium-235 is the radionuclide technetium-99 (⁹⁹Tc). It is considered a long-lived radioisotope with a half-life of 2.1x10⁵ years. It is a weak beta emitter with a max energy of 0.29 MeV and is most …

Synthesis And Characterization Of Porous Carbon Composite Derived From Biomass Waste For Supercapacitor Application, Cheng Kim Sim

Student Works (2020-2029)

Energy storage devices have gradually dominated human daily activities and indispensable to economy development such as supercapacitor and battery. There are few factors determining the performance of supercapacitor and active material is one of the crucial. Therefore, biomass such as pineapple peel (PP) and green waste (GW) were preferred and prior mixed with manganese and tin carbonate to synthesize carbon composite (PP/GW-ZMO and PP/GW-ZTO) via combustion. Brunauer–Emmett–Teller (BET) was employed to study the textural properties with the highest specific surface area obtained in PP-C (1765.92 m2g-1) and GW-C (1613.92 m2g-1). The existence of composite materials was examined using x-ray diffraction …

New Alkaloids From Selected Malaysian Alstonia And Lycopodium Species And Their Biological Activity, Soon Yee Joanne Yeap

Student Works (2020-2029)

Two Malaysian plants, Alstonia penangiana Sidiyasa (family: Apocynaceae) and Lycopodium platyrhizoma J.H.Wilce (family: Lycopodiaceae), were investigated for their alkaloidal composition. This project represents the first reported phytochemical study on these two plant species. A total of 94 alkaloids (1−94) were isolated and characterized from the leaf and stem-bark extracts of Alstonia penangiana, a plant endemic to Penang Island, Malaysia. Of these, 32 are new alkaloids. The leaf extract of A. penangiana yielded a total of 15 new alkaloids, including a pair of type-A and type-B macroline isomers (1, 2), four macroline oxindoles (20–23), three talpinine-type oxindoles (41–43), two ajmaline alkaloids …

Catalytic Esterification Of Palm-Based Lauric Acid Diethylene Glycol Via Microwave Heating, Abas Noor Azeerah

Student Works (2020-2029)

Diethylene glycol esters of fatty acids are mixtures of diethylene glycol mono- and di-esters of saturated and unsaturated fatty acids derived from edible oils and fats. The products are produced either by direct esterification of diethylene glycol with fatty acids or by transesterification of diethylene glycol with oils or fats. This study involved in maximizing the conversion of lauric acid to glycol ester via esterification with diethylene glycol, aided by calcined Zn-Mg-Al catalyst in a 250-ml reactor using both conventional and microwave heating. Preliminary catalytic screening involving tin (II) oxalate, Amberlyst-15 and calcined Zn-Mg-Al catalysts in esterification of lauric acid …

Integrated In Silico Techniques For Mechanism Studies Of Antiviral And Antidiabetic Compounds, Mohd Isa Diyana

Student Works (2020-2029)

Discovery and development of drug is an iterative process that involves identification of target and leads discovery, lead optimization and pre-clinical of biological profile and is continued until the drugs are eligible to be tested in the clinical phase. Computer-aided drug design (CADD) is an efficient way to overcome the demands of cost, time consumption and drug validation. CADD utilizes in silico technique approaches such as molecular docking to understand their binding pattern and affinity with the target protein and molecular dynamic (MD) simulations to provide an atomic view of the dynamic behavior and stability of bioactive compound inside the …

Crystal Structure Of The Catalytic C-Lobe Of The Hect-Type Ubiquitin Ligase E6ap, Lena K. Ries, Anna K.L. Liess, Christian G. Feiler, Donald E. Spratt, Edward D. Lowe, Sonja Lorenz

Chemistry

The HECT-type ubiquitin ligase E6AP (UBE3A) is critically involved in several neurodevelopmental disorders and human papilloma virus-induced cervical tumorigenesis; the structural mechanisms underlying the activity of this crucial ligase, however, are incompletely understood. Here, we report a crystal structure of the C-terminal lobe (“C-lobe”) of the catalytic domain of E6AP that reveals two molecules in a domain-swapped, dimeric arrangement. Interestingly, the molecular hinge that enables this structural reorganization with respect to the monomeric fold coincides with the active-site region. While such dimerization is unlikely to occur in the context of full-length E6AP, we noticed a similar domain swap in a …

Protonic Capacitor: Elucidating The Biological Significance Of Mitochondrial Cristae Formation, James Weifu Lee

Chemistry & Biochemistry Faculty Publications

For decades, it was not entirely clear why mitochondria develop cristae? The work employing the transmembrane-electrostatic proton localization theory reported here has now provided a clear answer to this fundamental question. Surprisingly, the transmembrane-electrostatically localized proton concentration at a curved mitochondrial crista tip can be significantly higher than that at the relatively flat membrane plane regions where the proton-pumping respiratory supercomplexes are situated. The biological significance for mitochondrial cristae has now, for the first time, been elucidated at a protonic bioenergetics level: 1) The formation of cristae creates more mitochondrial inner membrane surface area and thus more protonic capacitance for …

The Role Of Α, Γ, And Metastable Polymorphs On Electrospun Polyamide 6/Functionalized Graphene Oxide, Javier Macossay-Torres, Yazmin I. Avila-Vega, Faheem A. Sheikh, Travis Cantu, Francisco E. Longoria-Rodriguez, Edgar H. Ramirez-Soria, Rigoberto C. Advincula, Jose Bonilla-Cruz

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

The present paper describes the addition of nitroxide-functionalized graphene oxide (GOFT) into polyamide 6 (PA6) micro- and nanofibers, which were obtained through electrospinning. SEM micrographs demonstrated the presence of fibers. Tensile testing presented an unexpected and non-obvious behavior, in which the Young’s modulus, tensile strength, and elongation simultaneously and remarkably increased compared to the pristine polymer nanofibers. GOFT induces the hydrogen bonding between the NH group from PA6 with the functional groups, thus promoting higher crystallinity of the polymer matrix. Nonetheless, deconvoluted DSC curves revealed the presence of two quasi-steady polymorphous (b and d phases) contributing to 46% of the …

Effect Of Hydrothermal Temperature Treatment On The Variance Of Fluorescence In Ca2sio4:Tb3Þ, Rajaboopathi Mani, Santosh K. Gupta

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

Investigations of structural defects and their associated impact on the optical properties of optical materials are essential expediencies because different methods are involved in the preparation of those materials for display applications. Lanthanide ion doping is a simple structural probing strategy that facilitates the challenges of identifying the structural defects. Pure and terbium (Tb3+) doped Ca2SiO4 (C2S) particles were prepared using Pechini (C2SP) and hydrothermal methods (C2SH). From SEM images, it is observed that the Tb3+ doped C2SP particles were highly agglomerated, more than the C2SH particles. The TEM study confirmed that the particle size decreased for C2SH prepared at …

Preparation And Characterization Of Γ-Al2o3 Doped With Selected Elements And Correlating Surface Properties With The Catalytic Activity In Methanol Dehydration To Dimethyl Ether, Mo’Ath Ahmad Hasan

Chemistry Theses

The increasing demand for energy is associated with challenges that include environmental concerns and limited reserves. Dimethyl ether, DME, which can be obtained from different feedstocks, including natural gas and biomass, has recently been recognized as an ultra-clean environmentally friendly fuel due to the fact that it possesses unique characteristics that make it an efficient alternative fuel for diesel fuel engines. In addition, DME is an industrially important intermediate for a variety of chemicals. A promising potential route for dimethyl ether production is catalytic dehydration of methanol over solid acid catalysts. Therefore, exploring new solid acid catalytic materials and understanding …

Two Beta-Phosphorylamide Compounds As Ligands For Sm3+, Eu3+, And Tb3+: X-Ray Crystallography And Luminescence Properties, Alan R. Lear, Jonah Lenters, Michael G. Patterson, Richard J. Staples, Eric J. Werner, Shannon Biros

Open Access Publishing Support Funded Articles

This paper describes the synthesis of two beta-phosphorylamide ligands and their coordination chemistry with the Ln ions Tb3+, Eu3+, and Sm3+. Both the ligands and Ln complexes were characterized by IR, NMR, MS, and X-ray crystallography. The luminescence properties of the Tb3+ and Eu3+ complexes were also characterized, including the acquisition of lifetime decay curves. In the solid state, the Tb3+ and Sm3+ ligand complexes were found to have a 2:2 stoichiometry when analyzed by X-ray diffraction. In these structures, the Ln ion was bound by both oxygen atoms of each beta-phosphorylamide moiety of the ligands. The Tb3+ and Eu3+ …

Effect Of Polymer Design And Coating Formulation On The Water Uptake And Sensitivity Of Acrylic Water-Borne Films, William Z. Thompson

Master's Theses

Water-borne latex coatings represent a safer, more user-friendly, and environmentally responsible alternative to solvent-borne coatings, and are growing in popularity each year. However, these coatings often exhibit unfavorable performance when exposed to water for extended periods of time. This prolonged exposure often results in water uptake, which may give rise to other detrimental effects such as a decrease in modulus, blushing or water-whitening, reduced serviceable life, and softening of the film. In this study, various polymer composition latex design spaces are studied to develop an understanding of how water uptake can be modulated and minimized using common synthetic approaches. Factors …

Pegylated Block Copolymer For Cancer Imaging And Treatment, Sweety Singh

Dissertations

Gene theranostics have emerged as an important tool for the treatment of cancer as well as other diseases. Among the challenges in this field is the lack of effective vectors to chaperone plasmids into cells while the vector itself exhibits minimal toxicity. Herein, the synthesis, cellular uptake, and gene delivery using a biocompatible norbornene-based block copolymer is reported. This block copolymer, bearing polyethylene glycol moieties along with primary amines is functionalized with both a boron dipyrromethene (BODIPY) fluorophore for fluorescence tracking and a folic acid derivative for cancer cell targeting.

Stoichiometry control afforded residual unreacted amine functional groups available to …

Doped Carbonaceous Materials And Thin Films As Smart Materials For Pollutant Remediation And Electrocatalytic Applications, Bijay Paudel Chhetri

Theses and Dissertations

In this dissertation, we focused on utilizing naturally abundant, low-cost, environmentally benign, and renewable carbon precursors to synthesize doped carbonaceous materials as they are of particular interest in the scientific research because of their characteristic physiochemical properties. Such renewable bio-polymer derived doped carbonaceous hold potential applications in fuel cells, pollutant remediation, and many others. Due to the growing interest in developing high performance electrode materials for energy storage devices like supercapacitors, the design of thin-fils electrodes that delivered high specific capacitance with long term stability is essential. In chapter 1, the dissertation discussed backgrounds in carbon-based materials, renewable biopolymers, fuel …

Silver(I) And Copper(I) Complexes Of Semi‐Bulky Nitrogen‐Confused C‐Scorpionates, Denan Wang, Fathiya Jahan, Kristin J. Meise, Sergey V. Lindeman, James R. Gardinier

Chemistry Faculty Research and Publications

Two new sterically demanding nitrogen‐confused C‐scorpionate ligands with a bis(3,5‐diisopropylpyrazol‐1‐yl)methyl group bound to the 3‐ position of a normal pyrazole (^HL^iPr2) or an N‐toluenesulfonyl pyrazole (^TsL^iPr2) have been prepared. Reactions between the ligands (^xL^iPr2) and silver trifluoromethanesulfonate, AgOTf, gave four new compounds of the types [Ag(^xL^iPr2)](OTf) (x = Ts, 1a; x = H, 2a) or [Ag(^xL^iPr2)2](OTf) (x = Ts, 1b; x = H, 2b) depending on the initial metal:ligand ratio. Similarly, the reactions with [Cu(CH₃CN)_4](PF_{6 …}