Influence Of Synthesis Conditions On The Physicochemical And Electrocatalytic Properties Of Non-Stoichiometric Ba2sr2la2ti4o12 Perovskites,
2023
Institute of Electrochemistry and Energy Systems Acad. Evgeni Budevski, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., bl 10, 1113 Sofia, Bulgaria
Influence Of Synthesis Conditions On The Physicochemical And Electrocatalytic Properties Of Non-Stoichiometric Ba2sr2la2ti4o12 Perovskites, Ofeliya Kostadinova, Iliyan Popov, Simeon M. Stankov, Hristo Kolev, Tamara Petkov
Karbala International Journal of Modern Science
Present work studies the influence of the pretreatment milling media (deionized water (BLTOS-H) and isopropanol (BLTOS-i)) on the surface characteristics, structure, chemical composition and catalytic activity of non-stoichiometric Ba2Sr2La2Ti4O12 perovskites. The IR spectroscopy and XRD analyses shows a difference in the structure and phase composition of the two materials. X-ray photoelectron spectroscopy detects a Ba2+- and La3+-enriched and Sr2+-depleted surface. The BLTOS-i sample appears to exhibit higher specific surface area (SSA) and pore volume in comparison to BLTOS-H. The electrochemical tests showed that BLTOS-H sample have similar behavior to platinum at current densi-ties up to 10 mA cm-2, while BLTOS-i …
Running Shoe Pedometer,
2023
The University of Akron
Running Shoe Pedometer, Benjamin Kasper
Williams Honors College, Honors Research Projects
Running shoe pedometer aims to solve the issue of worn out running shoes. It can be difficult to know just how many miles you have run in your shoes and when a new pair is needed. Running in old shoes and worn out shoes is heavily linked to injury. My proposed project is a device that is powered by the compressive forces on the shoes soles that counts the number of steps the wearer takes using a microcontroller. Then, when the shoe reaches milestone that indicate it has been used 75% 90% and 100% of its expected life, it will …
Elucidation Of Active Site And Mechanism Of Metal Catalysts Supported In Nu-1000,
2022
Clemson University
Elucidation Of Active Site And Mechanism Of Metal Catalysts Supported In Nu-1000, Hafeera Shabbir
All Dissertations
Advances in extraction of shale oil and gas has increased the production of geographically stranded natural gas (primarily consisting of methane (C1) and ethane (C2)) that is burned on site. A potential utilization strategy for shale gas is to convert it into fuel range hydrocarbons by catalytic dehydrogenation followed by oligomerization by direct efficient catalysts. This work focuses on understanding metal cation catalysts supported on metal-organic framework (MOF) NU-1000 that will actively and selectively do this transformation under mild reaction conditions, while remaining stable to deactivation (via metal agglomeration or sintering). I built computational models validated by experimental methods to …
Intersections Of Environmentalism, Chemistry, And Racism: An Experimental Study Of Halobenzene Hydrogenolysis And Critical Communication Studies Of Equitable Learning Practices Rooted In Black Feminism,
2022
The University of Maine
Intersections Of Environmentalism, Chemistry, And Racism: An Experimental Study Of Halobenzene Hydrogenolysis And Critical Communication Studies Of Equitable Learning Practices Rooted In Black Feminism, Lauren O. Babb
Electronic Theses and Dissertations
Increasing concentrations of fluorinated aromatic compounds in surface water, groundwater, and soil pose threats to the environment. Fundamental studies that elucidate mechanisms of dehalogenation for C-X compounds (where X represents a halide) are required to develop effective remediation strategies. For halogenated benzenes, previously published research has suggested that the strength of the C-X bond is not rate-determining in the overall rate of dehalogenation. Instead, the rate-determining step has been hypothesized to be adsorption of the C-X compound onto the surface of a catalyst. Building on this hypothesis, in this work, we examine the reaction kinetics of fluorobenzene conversion to benzene, …
Wind Tunnel Modeling Of Jack Rabbit Ii Mock Urban Environment Gas Concentration Measurements,
2022
University of Arkansas, Fayetteville
Wind Tunnel Modeling Of Jack Rabbit Ii Mock Urban Environment Gas Concentration Measurements, Sami S. Fares
Graduate Theses and Dissertations
The 2015 Jack Rabbit (JR) II field trials were conducted to improve understanding of the denser-than-air dispersion of chlorine in an urban environment. The field study involved five large-scale, outdoor release trials of chlorine in a mock urban environment (MUE) at Dugway Proving Ground (DPG). Various instrumentation was deployed, including JazTM Ultraviolet-Visible (UV-Vis) point sensors capable of measuring gas-phase chlorine concentration throughout the mock urban array.
The Chemical Hazards Research Center (CHRC) was tasked by the Chemical Security Analysis Center (CSAC) with the Mock Urban Wind Tunnel (MUWT) program to study the 2015 JR II Trials at wind tunnel scale. …
Performance And Fouling During Bioreactor Harvesting,
2022
University of Arkansas, Fayetteville
Performance And Fouling During Bioreactor Harvesting, Da Zhang
Graduate Theses and Dissertations
Tangential flow filtration has many advantages for bioreactor harvesting as the permeate could be introduced directly to the subsequent capture step, the process is easy to scale up, and fouling of the filter is limited by the cross flow. However, membrane fouling has limited its widespread use. This is particularly problematic given the high cell densities encountered today. Here a reverse asymmetric commercial membrane, BioOptimal™ MF-SL (Asahi Kasei), where the more open surface faces the feed stream, and the tighter barrier layer faces the permeate stream, has been investigated for bioreactor harvesting. The open surface contains pores up to 40 …
Chromatographic Dynamic Chemisorption,
2022
University of Massachusetts Amherst
Chromatographic Dynamic Chemisorption, Shreya Thakkar
Masters Theses
Reaction rates of catalytic cycles over supported metal catalysts are normalized by the exposed metal atoms on the catalyst surface, reported as site time yields which provide a rigorous standard to compare distinct metal surfaces. Defined as the fraction of exposed metal surface atoms to the total number of metal atoms, it is important to measure the dispersion of supported metal catalysts to report standardized rates for kinetic investigations. Multiple characterization techniques such as electron microscopy, spectroscopy and chemisorption are exploited for catalyst dispersion measurements. While effective, electron microscopy and spectroscopy are not readily accessible due to cost and maintenance …
Photocatalytic Degradation Of Organic Contaminants By Titania Particles Produced By Flame Spray Pyrolysis,
2022
Mississippi State University
Photocatalytic Degradation Of Organic Contaminants By Titania Particles Produced By Flame Spray Pyrolysis, Noah Babik
Theses and Dissertations
Advanced oxidation of organic pollutants with TiO2 photocatalysts is limited due to the wide bandgap of TiO2, 3.2 eV, which requires ultraviolet (UV) radiation. When nanosized TiO2 is modified by carbon doping, charge recombination is inhibited and the bandgap is narrowed, allowing for efficient photodegradation under visible light. Here, we propose a flame spray pyrolysis (FSP) technique to create TiO2. The facile process of FSP has been successful in preparing highly crystalline TiO2 nanoparticles. Using the same procedure to deposit TiO2 onto biochar, the photocatalyst was doped by the carbonaceous material. The morphology, crystalline and electronic structure of the FSP …
Optimization Of Styrene From Ethylbenzene Case Study,
2022
University of Mississippi
Optimization Of Styrene From Ethylbenzene Case Study, Jabria Daria Thompson
Honors Theses
The following pages detail the optimization process of styrene from ethylbenzene in the Styrene Production Plant, Unit 500. There were two parts of the assignment, each with slightly different end goals. The goal of the first part of the assignment, was to create a process that would effectively and efficiently increase the negative Net Present Value (NPV) of the production plant. Procedures taken in this process included developing a working kinetic process simulation model and optimizing this model through unit operations and heat integration, as well as developing an accurate economic model that will be used to evaluate the proposed …
Kinetics Of Carboxymethylation Reaction Of Cellulose Samples With Different Degree Of Crystallinity,
2022
Institute of Polymer Chemistry and Physics, Tashkent, Uzbekistan
Kinetics Of Carboxymethylation Reaction Of Cellulose Samples With Different Degree Of Crystallinity, Ilkhom Goyibnazarov, Sherzod Yuldoshov, Abdushukhur Sarimsokov
CHEMISTRY AND CHEMICAL ENGINEERING
No abstract provided.
Mathematical Modeling Of Synthesis 4´,4´´-Di-(1-Methyl-1-Hydroxy-2-Phenylethynyl)-Dibenzo-18-Crown-6,
2022
National University of Uzbekistan, Tashkent, Uzbekistan
Mathematical Modeling Of Synthesis 4´,4´´-Di-(1-Methyl-1-Hydroxy-2-Phenylethynyl)-Dibenzo-18-Crown-6, Lyubov Kozinskaya, Dilorom Mirkhamitova
CHEMISTRY AND CHEMICAL ENGINEERING
The main goal of this study is the mathematical modeling of the optimal conditions for the synthesis of 4´,4´´-di-(1-methyl-1-hydroxy-2-phenylethynyl)-dibenzo-18-crown-6 by the least squares method. In the STAT program, iconograms of mathematical modeling of the synthesis and the dependence of the rate of formation of 4´,4´´-di-(1-methyl-1-hydroxy-2-phenylethynyl)-dibenzo-18-crown-6 on temperature and reaction time were obtained, the corresponding analytical dependencies are determined. Mathematical processing of the results of the synthesis of 4´,4´´-di-(1-methyl-1-hydroxy-2-phenylethynyl)-dibenzo-18-crown-6 was carried out, a system of linear equations was compiled using the matrix method. The average reaction rate and the optimum of the mathematical model were determined, and the experimental and calculated …
Optimization Of A Fluidized Bed Reactor For The Production Of Styrene From Ethylbenzene,
2022
University of Mississippi
Optimization Of A Fluidized Bed Reactor For The Production Of Styrene From Ethylbenzene, Gregory Espenan
Honors Theses
In order to optimize Unit 500, a styrene production plant, the Net Present Value (NPV) was used as the objective function to ensure every optimization strategy had a positive economic effect. To optimize a chemical plant, it is important to note efficiency, economics, product specifications, and production requirements. The goal of this project was to make changes to the base case of Unit 500 to minimize the cost to produce styrene for an upstream unit. PRO/II was used to simulate various points in different unit operations throughout the process. The NPV was measured after each unit operation was simulated to …
Analyzing The Surface Chemistry Of Ni-Fe Hydroxide Alloy Nanoparticles As Catalysts For The Oxygen Evolution Reaction By X-Ray Photoelectron Spectroscopy Analysis,
2022
University of Arkansas, Fayetteville
Analyzing The Surface Chemistry Of Ni-Fe Hydroxide Alloy Nanoparticles As Catalysts For The Oxygen Evolution Reaction By X-Ray Photoelectron Spectroscopy Analysis, Lauren B. Shepard
Chemical Engineering Undergraduate Honors Theses
Water electrolysis has been proposed as a renewable source of hydrogen, a possible replacement to harmful fossil fuels. This process can be broken down into two half reactions, the hydrogen evolution reaction and the oxygen evolution reaction. Because the oxygen evolution reaction has slow kinetics and a high overpotential to overcome, a catalyst is needed to speed up the kinetics and ensure faster and more efficient production of molecular hydrogen. The use of Ni-Fe hydroxide alloy nanoparticles as a catalyst has been shown to significantly improve the efficiency of the reaction by decreasing the overpotential, making the process more energy …
Electrode Development Of Water Electrolyzer Cells For Low-Cost And High-Efficiency Hydrogen Production,
2022
University of Tennessee, Knoxville
Electrode Development Of Water Electrolyzer Cells For Low-Cost And High-Efficiency Hydrogen Production, Shule Yu
Doctoral Dissertations
A worldwide increase in energy demand and a latent crisis in the fossil fuel supply have spurred broad research in the renewable energy. Currently, most renewable energy resources (e.g., hydro, wind, solar, tide) face supply challenges as they are known to be intermittent, unstable, and locally shackled, which calls for urgent development in energy storage and conversion. Hydrogen is regarded as an ideal energy carrier with its advantages (e.g., high energy density, environmentally friendliness, and low weight). In practice, the proton exchange membrane electrolyzer cell (PEMEC) is considered to be one of the optimal hydrogen production and energy storage devices …
Optimizing Virus Prefiltration For Biopharmaceutical Manufacturing,
2022
University of Arkansas, Fayetteville
Optimizing Virus Prefiltration For Biopharmaceutical Manufacturing, Solomon Isu
Graduate Theses and Dissertations
Virus filters are single-use devices that use a size-based separation process. In virus filters, contaminating virus particles are retained while the therapeutic molecules pass through the membrane pores. Virus filters are an essential component of the overall virus clearance strategy. Sections 1 and 2 of this dissertation provide an introduction and extensive review of monoclonal antibody (mAb) process development, where virus filtration is pivotal. In section 3, prefiltration studies were performed with an industrially relevant IgG1 type mAb using adsorptive and size-exclusion-based prefilters with different mechanisms of action. This mAb has an isoelectric point range of 7.1 to 8.0 and …
Catalytic Ring Opening Of Mono- And Bicyclic Compounds For The Production Of Renewable Diesel And Jet Fuel,
2022
University of Maine
Catalytic Ring Opening Of Mono- And Bicyclic Compounds For The Production Of Renewable Diesel And Jet Fuel, Matthew J. Kline
Electronic Theses and Dissertations
Thermal DeOxygenation (TDO) is a process that converts organic acids produced from cellulose hydrolysis and dehydration into a low-oxygen bio-oil containing substituted naphthene compounds. The high aromatic content is desirable for gasoline fractions, but middle distillates such as diesel and jet fuel require upgrading via hydrogenation and ring opening to achieve better combustion characteristics. Previous research has demonstrated that TDO oil could be hydrogenated over high-surface-area nickel catalysts to improve the combustion characteristics, but the cetane number was still below the specifications.
Multiple supported catalysts were synthesized by ion exchange and incipient wetness impregnation, and the catalysts were characterized by …
Computational Rational Design Of Electrocatalysts For Electrochemical Ammonia And Hydrogen Synthesis,
2022
University of Massachusetts Amherst
Computational Rational Design Of Electrocatalysts For Electrochemical Ammonia And Hydrogen Synthesis, Akash Jain
Doctoral Dissertations
The electrochemical hydrogen evolution reaction (HER) and nitrogen reduction reaction (NRR) offer fossil-fuel-free routes for hydrogen and ammonia synthesis, respectively. However, currently, both processes lack suitable electrocatalysts for practical applications. Thus, this dissertation focuses on the computational rational design of HER and NRR electrocatalysts.
HER is most efficiently catalyzed by platinum (Pt), which is expensive. To reduce the catalyst cost, we investigate core-shell nanoparticles of inexpensive tungsten-carbide (WC) and Pt (WC@Pt). Using first-principles density functional theory (DFT) calculations, we compare the suitability of two WC phases, α-WC and β-WC as support materials for Pt overlayers. We dope WC with titanium …
Understanding The Photodegradation Mechanism Of Gaseous Acetaldehyde Over Bi2wo6 – Modified Znwo4 Photocatalyst Under Uv Light Irradiation,
2022
National University of Uzbekistan, Uzbekistan-Japan Innovation Center of Youth, Tashkent, Uzbekistan
Understanding The Photodegradation Mechanism Of Gaseous Acetaldehyde Over Bi2wo6 – Modified Znwo4 Photocatalyst Under Uv Light Irradiation, Mirabbos Hojamberdiev, Ronald Vargas, Shahlo Daminova, Zuhra Kadirova
CHEMISTRY AND CHEMICAL ENGINEERING
Indoor air quality has a significant impact on human health as people spend more time indoors. As a common indoor air pollutant, acetaldehyde is considered toxic when exposed to it for a prolonged period. The aim of this study is the enhancement of the photocatalytic activity of ZnWO4 with a monoclinic wolframite structure for degradation of gaseous acetaldehyde by modifying its surface with Bi2WO6 layered structure. The mechanisms behind the enhanced photocatalytic activity and the pathways for acetaldehyde photodegradation over the Bi2WO6-modified ZnWO4 photocatalyst are discussed.
Modelling Of Reаctive Distillаtion Process For Etherificаtion Reаction,
2022
Shаhrisаbz brаnch of the Tаshkent Сhemicаl-Technologicаl Institute, Shаhrisаbz, Uzbekistаn
Modelling Of Reаctive Distillаtion Process For Etherificаtion Reаction, Adham Norkobilov, Olimjon Mаksudov, Abdulaziz Bаkhtiyorov, Orifjon Zаripov, Abbos Elmаnov
CHEMISTRY AND CHEMICAL ENGINEERING
А reаctive distillаtion system is exаmined to produce for the production of Ethyl tert butyl ether (ETBE) viа etherificаtion of isobutene with ethаnol. Optimizаtion methods using heаt integrаtion аre аlso conducted. The molаr reflux rаtio аnd reboiler duty аre cаlculаted using sensitivity аnаlysis. The bottom streаm with the sаtisfied purity of ETBE is integrаted for heаting the feed streаm to the column. Heаt integrаtion from reаctor heаt to the initiаl feed streаm аnd from bottom streаm of the column to the column inlet streаm with the purpose of аchieving tаrget feed temperаture leаds to high conversion in the reаctive distillаtion …
Design And Fabrication Of Nanostructured Electrodes For Complementary Electrochemical And Photoelectrochemical Water Splitting,
2022
The American University in Cairo AUC
Design And Fabrication Of Nanostructured Electrodes For Complementary Electrochemical And Photoelectrochemical Water Splitting, Kholoud El Sayed Abousalem
Theses and Dissertations
Designing highly active, durable, and nonprecious electrodes for overall water splitting is of urgent scientific importance to realize sustainable hydrogen production. Accordingly, the need to search efficient energy production systems is of crucial necessity. In this thesis, two various systems for sustainable hydrogen production have been reported using electrochemical and photoelectrochemical pathways. In the first part of the thesis, electrochemical water splitting involving both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) has been established. To this end, an innovative approach is demonstrated to synthesize flower-like 3D homogenous trimetallic Mn, Ni, Co phosphide catalysts directly on nickel foam via …