Chemical Engineering Commons^™

Adsorption Kinetics And Phase Behavior Of Particles Adsorbed At An Interface, Shaghayegh Darjani

Dissertations and Theses

The ability to predict the adsorption dynamic, phase behavior, and surface pressure of a monolayer of adsorbed particles in two-dimensional systems are key aspects of many current research areas. Examples include phase transitions in amphiphilic monolayers, emulsion stability due to particle adsorption at interfaces, and melting at an interface.

In this thesis, a new approach for deriving the equation of state for a two-dimensional lattice gas is proposed, based on arguments similar to those used in the derivation of the Langmuir-Szyszkowski equation of state for localized adsorption. This work aims to predict the adsorption kinetics and phase behavior of a …

A New Mathematical Theory For The Dynamics Of Large Tumor Populations, A Potential Mechanism For Cancer Dormancy & Recurrence And Experimental Observation Of Melanoma Progression In Zebrafish, Adeyinka A. Lesi

Dissertations and Theses

Cancer, a family of over a hundred disease varieties, results in 600,000 deaths in the U.S. alone. Yet, improvements in imaging technology to detect disease earlier, pharmaceutical developments to shrink or eliminate tumors, and modeling of biological interactions to guide treatment have prevented millions of deaths. Cancer patients with initially similar disease can experience vastly different outcomes, including sustained recovery, refractory disease or, remarkably, recurrence years after apparently successful treatment. The current understanding of such recurrences is that they depend on the random occurrence of critical mutations. Clearly, these biological changes appear to be sufficient for recurrence, but are they …

Molecular To Macroscopic Understanding Of Chloroaluminate Anion Intercalation In Rechargeable Aluminum-Graphite Batteries, Jeffrey Xu

Dissertations and Theses

Today’s global energy challenges pose an urgent need to electrify transportation and better store intermittent renewable energy sources (e.g., solar and wind energy). For such large-scale battery applications, aluminum batteries are a promising “beyond lithium-ion” technology due to the high volumetric capacity, earth abundance, low-cost, and inherent safety of aluminum metal. However, there are very few compatible positive electrode materials that exhibit high energy density and cycling stability, in part due to the challenges of electrochemically intercalating highly charged Al³⁺ cations. Recently, graphite has been demonstrated as a promising positive electrode material in non-aqueous rechargeable aluminum batteries, which store …

Molecular-Level Understanding Of Ionic & Electronic Charge Storage Mechanisms In Rechargeable Aluminum Batteries Using Sold-State Nmr, Ankur Lahanu Jadhav

Dissertations and Theses

Rechargeable aluminum-ion batteries are safe and low-cost alternatives to traditional lithium-ion batteries due to the high volumetric capacity (8040 mAh/cm³) of aluminum. However, very few electrode materials have shown reversible aluminum ion intercalation. Intercalation Al³⁺ ions in these structures leads to poor capacity retention, mainly due to slow solid-state diffusion of the highly charged tri-valent aluminum ions within these crystalline structures. In 2015, aluminum ions were shown to reversibly intercalate/de-intercalate into the Chevrel Mo₆S₈ phase, though the intercalation mechanism is not well understood. Alternatively, molecular chloroaluminate ions within the ionic liquid electrolyte have also …

Development Of Light Actuated Chemical Delivery Platform On A 2-D Array Of Micropore Structure, Hojjat Rostami Azmand, Hojjat Rostami Azmand

Dissertations and Theses

Localized chemical delivery plays an essential role in the fundamental information transfers within biological systems. Thus, the ability to mimic the natural chemical signal modulation would provide significant contributions to understand the functional signaling pathway of biological cells and develop new prosthetic devices for neurological disorders. In this paper, we demonstrate a light-controlled hydrogel platform that can be used for localized chemical delivery in a high spatial resolution. By utilizing the photothermal behavior of graphene-hydrogel composites confined within micron-sized fluidic channels, patterned light illumination creates the parallel and independent actuation of chemical release in a group of fluidic ports. The …

Development Of Novel Inks And Approaches For Printing Tissues And Organs, Shen Ji

Dissertations

Tissue engineering is a multidisciplinary field that investigates and develops new methods to repair, regenerate and replace damaged tissues and organs, or to develop biomaterial platforms as in vitro models. Tissue engineering approaches require the fabrication of scaffolds using biomaterials or fabrication of living tissues using cells. As the demands of customized, implantable tissue/organs are increasing and becoming more urgent, conventional scaffold fabrication approaches are difficult to meet the requirements, especially for complex large-scale tissue fabrication. In this regard, three-dimensional (3D) printing attracted more interest over the past decades due to its unrivaled ability to fabricate highly customized tissues or …

The Aging And Impacts Of Atmospheric Soot: Closing The Gap Between Experiments And Models, Ogochukwu Yvonne Enekwizu

Dissertations

The main goal of this dissertation is to generate data and parameterizations to accurately represent soot aerosols in atmospheric models. Soot from incomplete combustion of fossil fuels and biomass burning is a major air pollutant and a significant contributor to climate warming. The environmental impacts of soot are strongly dependent on the particle morphology and mixing state, which evolve continuously during atmospheric transport via a process known as aging. To make predictions of soot impacts on the environment, most atmospheric models adopt simplifications of particle structure and mixing state, which lead to substantial uncertainties. Using an experimentally constrained modeling approach, …

Modeling Mass Transfer And Chemical Reaction In Industrial Nitrocellulose Manufacturing Processes, Francis Patrick Sullivan

Dissertations

A series of models are proposed to describe the production of military grade nitrocellulose from dense cellulose materials in mixtures of nitric acid, sulfuric acid, and water. This effort is conducted to provide a predictive capability for analyzing the rate and extent of reaction achieved under a range of reaction conditions used in the industrial nitrocellulose manufacturing process for sheeted cellulose materials. Because this capability does not presently exist, nitrocellulose producers have historically relied on a very narrow range of cellulose raw materials and resorted to trial and error methods to develop processing conditions for new materials. This tool enables …

Development Of Novel Membranes For Nanocarbon Enhanced Separation With Application In Biofuels And Solvent Recover, Oindrila Gupta

Dissertations

Pharmaceutical industries historically have had one of the highest amounts of solvent waste generated per unit of drug manufactured. Energy requirements and carbon footprint of current solvent recycling processes tend to be quite high, and the incineration of the solvents for waste disposal produces toxic air emissions. Also, rapidly increasing demand for energy and strict regulation on engine pollutant emissions have necessitated the use of alcohol as carbon-neutral fuels. Thermal distillation is one of the most common methods for the separation of alcohol-water mixtures. However, its application is limited due to energy requirements and high operating costs, and heating to …

Predicting Bulk-Scale Properties Of Pharmaceutical Powders From Their Particle-Scale Dimensionless Measures, Kuriakose T. Kunnath

Dissertations

Loose powder packing and flowability are both important bulk properties to consider in relation to pharmaceutical tablet and capsule manufacturing. These properties as well as cohesive powder agglomeration tendency impact the efficiency of various processes such as feeding, blending, conveying, and compaction, and could have an adverse effect on final drug product. Pharmaceutical powders are often milled to fine sizes (<100 gm) for dissolution improvements via increased available surface area. However, such particle size reductions lead to inadequate bulk powder properties due to high cohesion among the individual particles. Recent work has demonstrated the ability of nano-silica dry coating techniques to significantly decrease interparticle forces without changes in particle size. In this work, the ability to predict properties such as powder bed porosity, flowability, and particle agglomeration both before and after nano-silica dry coating is examined, along with assessment of the extent of property enhancements after dry coating. Previous studies have utilized empirical approaches to build property prediction models. However, such approaches lack physical fundamentals which dictate bulk powder behavior and would be unable to account for the effects of dry powder coating. Incorporation of physics can be done via computation of the granular Bond number, as is done in this study for a large dataset of commonly used pharmaceutical powders, with wide variations in particle size, shape, density, and surface roughness. Predictive capability of current Bond number models is investigated, reasons for outliers are elucidated, and amendments to improve prediction is attempted. Overall, the aim of this work is to expand generalizability of Bond number models to a wider variety of particles, and extend its use from single powders to multi-component mixtures. The major outcome of this work is the development of a predictive framework that is expected to simplify pharmaceutical dry powder formulation development, reduce required experimental testing, and provide quantifiable estimates to aid processing route decision making.

Effects Of Calcination Temperature Of Naturally Occurring Absorbents On Drinking Water Defluoridation, Brenda Mndolwa

Tanzania Journal of Engineering and Technology (TJET)

Currently, in Tanzania, fluoride removal from drinking water is treated mostly using the bone char method. The method has poor acceptability in some religious communities and also causes water quality deterioration in taste and odour if the bones are not properly prepared. The use of local natural adsorbents as an alternative is feasible with limitations of high levels of other impurities in treated water. Locally available gypsum, magnesite and bauxite were converted to adsorbents through calcination. The study was conducted to determine the removal efficiency, best calcination temperature and composite ratio of the three adsorbents for the removal of fluoride …

Fermentability Of Concentrated Sulfuric Acid Hydrolyzates From Aspenwood And Pinewood, Kando Janga

Tanzania Journal of Engineering and Technology (TJET)

The fermentability of hydrolyzates derived from two-stage concentrated sulfuric acid hydrolysis of Trembling aspen (Populus tremula) and Scots pine (Pinus sylvestris) were investigated. Three types of hydrolyzates were produced at mild, moderate and high decrystallization severity conditions. Portions of each of the original hydrolyzates were concentrated by vacuum evaporation to increase the sugar fraction to simulate industrial applications. Both sets of hydrolyzates were fermented anaerobically using Saccharomyces cerevisiae ATCC 96581. After 23 hours of fermentation, complete glucose consumption was observed for all the original hydrolyzates, with no signs of inhibition. The ethanol yields from these hydrolyzates ranged from 68% to …

Preparation And Characterization Of Reactive Composites Combining Boron With Mixed Oxides, Purvam Mehulkumar Gandhi

Theses

Thirteen liquids have been explored as Process Control Agents (PCAs) for high-energy mechanical milling of two metal oxide powders, CuO and Bi₂O₃, with the practical purpose to reduce the sizes of powder particles and refine their crystal structure. Multiple liquid properties have been considered to analyze their effect on evolution of both particle and crystallite sizes during milling for each oxide. Experimental data were analyzed using the δ-AICc (Akaike Information criterion) correlation function applied to linear relations between liquid properties and powder characteristics. Multiple linear correlation models were ranked based on the highest log-likelihood and the …

Optimal Conditions Of Fermentation Of The Pichia Pastoris Yeast Expressing The Recombinant Pres2-S Protein (M-Hbsag) Of Hepatitis B Virus (Hbv), Sasmakоv Sobirdjan, Ashirоv Оybek, Abdurakhmanоv Jaloliddin, Xasanоv Shuhrat

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this study is determination of optimal fermentation conditions of the Pichia pastoris yeast expressing the recombinant Pres2-S protein of hepatitis B virus (HBV). For this purpose we investigated the main factors influencing for the cultivation of recombinant strain of the yeast Pichia pastoris pPIC3,5-S-HBsAg - the composition of the nutrient medium, pH and dissolved oxygen (DO). As a result, by enzyme-linked immunosorbent assay (ELISA) the optimal concentration of methanol ≈1.0 %, which is the initiator and the only source of carbon for protein expression in the Mut+ phenotype Pichia pastoris yeast cells was determined. In the selected …

Waste Engine Oil Regeneration With Bentonite From The Navbahor Deposit, Azimova Shodiyakhon, Arslanov Sharafutdin, Turakhujayev Saidakbar, Azimov Dilmurod

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the study was the regeneration of used oils. The change in the conditions for the regeneration of used engine oil as a result of adsorptive cleaning with alkaline earth clay from the Navbakhor deposit has been studied. The carried-out regeneration allows almost completely removing mechanical impurities, moisture from the waste oil and helps to clarify it. The optimal conditions for regeneration have been established. The removal of secondary products formed during the use of engine oil while retaining the main components that determine the serviceability of the product has been established. By means of IR spectroscopy, as …

Mixed Complex Compounds Of Palmitate, Oleate Calcium With Acetamide, Nicotinamide And Thiocarbamide, Ibadullaeva Tursunoy, Azizov Tokhir, Ibragimova Мavluda

CHEMISTRY AND CHEMICAL ENGINEERING

The purpose of the study was the synthesis and study of the structure of mixed complexes of palmitate, calcium oleate with acetamide, nicotinamide and thiocarbamide. The mixed coordination compounds of palmitate and calcium oleate were synthesized. The composition, individuality, thermal behavior, methods of coordinating the palmitate and oleate fragments, acetamide, nicotinamide and thiocarbamide molecules have been established. Comparison of the diffraction patterns of calcium palmitate and oleate, free ligand molecules and synthesized compounds showed the mismatch of the diffractograms, conseqently that the synthesized complexes have an individual crystal lattice different from the starting materials. The method of coordination of amide …

Synthesis Of Esters Of Halogenoacetic Acids, Yuldasheva Muxabbat, Turaev Sherzod

CHEMISTRY AND CHEMICAL ENGINEERING

Amidoalkylating reagents containing a phthalimide group are used in the synthesis of hard-to-reach primary amines and complex heterocyclic compounds. These types of amidoalkylating compounds are suitable reagents for nucleophilic substituted reactions in acidic media due to their resistance to acids. Result of reactions of amidoalkylating reagents-N-hydroxyethylphthalimide and N-hydroxymethylphthalimide with aliphatic carbonic acids can also produce new bactericidal and fungicidal esters. In this study, halogen acids reacted with N-hydroxymethylphthalimide monochloric acetic acid, monobromic acetic acid, monoiodic acetic acid, trifluoric acetic acid and trichloroacetic acid, as well as, N-b-hydroxyethylphthaleidyl monohydric acid. As a result of the reactions, new phthalimidomethyl and phthalimidoethyl esters …

Carbon Nanotube–Liposome Complexes In Hydrogels For Controlled Drug Delivery Via Near-Infrared Laser Stimulation, S. Zahra M. Madani, Mohammad Moein Safaee, Mitchell Gravely, Carolynn Silva, Stephen Kennedy, Geoffrey D. Bothun, Daniel E. Roxbury

Chemical, Biomolecular, and Materials Engineering Faculty Publications

Externally controllable drug delivery systems are crucial for a variety of biological applications where the dosage and timing of drug delivery need to be adjusted based on disease diagnosis and progression. Here, we have developed an externally controllable drug delivery system by combining three extensively used platforms: hydrogels, liposomes, and single-walled carbon nanotubes (SWCNTs). We have developed carbon nanotube–liposome complexes (CLCs) and incorporated these structures into a 3D alginate hydrogel for use as an optically controlled drug delivery system. The CLC structures were characterized by using a variety of imaging and spectroscopic techniques, and an optimal SWCNT/lipid ratio was selected. …

Numerical Simulations Of Current And Temperature Distribution Of Symmetrical Double-Cathode Solid Oxide Fuel Cell Stacks Based On The Theory Of Electric-Chemical-Thermal Coupling, Cheng-Rong Yu, Jian-Guo Zhu, Cong-Ying Jiang, Yu-Chen Gu, Ye-Xin Zhou, Zhuo-Bin Li, Rong-Min Wu, Zheng Zhong, Wan-Bing Guan

Journal of Electrochemistry

Solid oxide fuel cell (SOFC) is a high-efficient clean conversion device for future energy management. Because of the low antioxidant reduction ability and complex thermal stress, the structure of traditional asymmetrical thin anode-supported planar SOFC is easily to be broken under stack operating conditions. To overcome these defects, a new complete symmetrical SOFC based on double-sided cathodes was developed. To study the influences of gas flow direction and current collection mode on the cell performance inside stack, a numerical model was established by finite element method based on the theory of electro-thermo-chemo multiphysical coupling. By applying this model, the molar …

Plastic Crystal - Gel Polymer Electrolytes For Magnesium Rechargeable Batteries, Diyana Hambali

Student Works (2020-2029)

Polymer electrolytes are known to be the possible substitution for liquid electrolytes due to their excellent safe performance and good compatibility with electrodes compared to its liquid counterpart. Thus, in the present work, gel polymer electrolytes (GPEs) have been studied comprising plastic crystal succinonitrile (SN) to form plastic crystal - gel polymer electrolytes. The GPEs were prepared by using two types of magnesium salts which are magnesium trifluoromethanesulfonate (MgTf2) and magnesium bis(trifluoromethanesulfonimide) (Mg(TFSI)2) varied from 5 to 30 wt.%. In the preparation of GPEs, four GPE systems were introduced which are single plasticized systems (PVdC-co-AN/SN/MgTf2 and PVdC-co-AN/SN/Mg(TFSI)2) and double plasticized …