Engineering Commons^™

Formulation Strategies To Enhance Solubility And Permeability Of Small Molecules For Drug Delivery Applications, Pradeep Kumar Bolla

Open Access Theses & Dissertations

All the new chemical entities/drug molecules intended for therapeutic use must be administered using an appropriate delivery system/dosage form to achieve maximum bioavailability. However, designing a drug delivery system is complex as several factors such as lipophilicity, molecular mass, crystallinity, ionic charge, polymorphic forms and hydrogen bonding) affect the solubility and permeability of these molecules. Biopharmaceutics drug classification system (BCS) categorizes the existing drugs into four classes based on the aqueous solubility and membrane permeability and it is reported that >70% of the drugs are poorly soluble and belong to BCS class II and BCS class IV. Several physical, chemical …

Structural Analysis Of Deformed Caprock Associated With A Salt Shoulder At Gypsum Valley Salt Wall, Paradox Basin, Colorado, Hanah Draper

Open Access Theses & Dissertations

This study documents the style and distribution of deformation present in Triassic-age gypsic and carbonate caprock associated with the Gypsum Valley Salt Wall Salt Shoulder in the Paradox Basin, Colorado in order to determine the mechanism and timing of deformation. Mapping of gypsic and carbonate capstone facies shows that the caprock layering that was generated during formation has been deformed by large-and-small-scale folding and faulting, brecciation, and boudinage. Deformation within the caprock resulted in widely variable orientations along the length of the salt shoulder, that also varies locally in intensity of deformation and with proximity to the passively rising diapir …

Comparison Of Pyrolysis Of Live Wildland Fuels Heated By Radiation Vs. Convection, Mohammad-Saeed Safdari, Elham Amini, David R. Weise, Thomas H. Fletcher

Faculty Publications

During wildland fires, which include both planned (prescribed fire) and unplanned (wildfire) fires, live and dead plants may be subject to both radiative and convective heat transfer mechanisms. In this study, the pyrolysis of 14 live plant species native to the forests of the southern United States was investigated using a flat-flame burner (FFB) apparatus under three heating modes in order to mimic pyrolysis of plants during wildland fires. The heating modes were: (1) radiation-only, where the plants were pyrolyzed under a moderate heating rate of 4 °C s−1 (radiative flux of 50 kW m−2); (2) convection-only, where the FFB …

Evaluation Of Nox‑Reduction Measures For Iron-Ore Rotary Kilns, Rikard Ekland, Thomas Allguren, Christian Fredriksson, Denver Haycock, Colson Johnson, Jacob Fransen, Thomas H. Fletcher, Klas Andersson

Faculty Publications

The grate-kiln process is employed for sintering and oxidation of iron-ore pellets. In this process, a fuel (typically coal) is combusted with a large amount of excess air in a rotary kiln, and the high air-to-fuel ratio leads to significant NOx formation. The current Article is an assessment of NOx reduction measures that have been tested in pilot-scale and in full-scale by the Swedish iron-ore company Luossavaara-Kiirunavaara Aktiebolag (LKAB). The results show that the scaling between the full-scale kiln and the pilot-scale kiln is crucial, and several primary measures that reduce NOx significantly in pilot-scale achieve negligible reduction in full-scale. …

Chemical And Thermal Sintering Of Supported Metals With Emphasis On Cobalt Catalysts During Fischer−Tropsch Synthesis, Mahmood Rahmati, Mohammad-Saeed Safdari, Thomas H. Fletcher, Morris D. Argyle, Calvin H. Bartholomew

Faculty Publications

This comprehensive critical review combines, for the first time, recent advances in nanoscale surface chemistry, surface science, DFT, adsorption calorimetry, and in situ XRD and TEM to provide new insights into catalyst sintering. This work provides qualitative and quantitative estimates of the extent and rate of sintering as functions of nanocrystal (NC) size, temperature, and atmosphere. This review is unique in that besides summarizing important, useful data from previous studies, it also advances the field through addition of (i) improved or new models, (ii) new data summarized in original tables and figures, and (iii) new fundamental perspectives into sintering of …

In Situ Image Processing And Data Binning Strategy For Particle Engineering Applications, Toufic El Arnaout, Patrick J. Cullen

Articles

Crystallization control can be improved through real-time monitoring technologies. Here, a workflow is demonstrated on rapid batch cooling crystallization of L-glutamic acid. First, in situ images were generated using video microscopy sensors and analyzed, by employing a single, rapid macro code to extract particle data descriptors. A binning procedure (over time) was performed, where every data point represented the counts of particles within a specific size or shape range per 100 images. This binning method was found more informative in tracking of the populations compared to whole image averages or individual particle datapoints. This study provides a step-by-step guide towards …

Synergistic Effect Of Hydrophilic Nanoparticles And Anionic Surfactant On The Stability And Viscoelastic Properties Of Oil In Water (O/W) Emulations; Application For Enhanced Oil Recovery (Eor), Sarmad Al-Anssari, Zain-Ul-Abedin Arain, Haider A. Shanshool, Alireza Keshavarz, Mohammad Sarmadivaleh

Research outputs 2014 to 2021

With the rapidly increased global energy demand, great attention has been focused on utilizing nanotechnology and particularly nanofluids in enhanced oil recovery (EOR) to produce more oil from low-productivity oil reservoirs. Nanofluid flooding has introduced as one of the promising methods for enhanced oil recovery using environment-friendly nanoparticles (NPs) to be as an innovative-alternative for chemical methods of EOR. This work investigates the synergistic effects of anionic surfactant and hydrophilic silica nanoparticles on the stability and the mechanical behavior of oil in water (O/W) emulsions for their application in EOR. To achieve this, an extensive series of experiments were conducted …

Customized Boron And Magnesium-Based Reactive Materials Prepared By High Energy Mechanical Milling, Xinhang Liu

Dissertations

New reactive materials need to be developed having biocidal combustion products. When ignited, such material can add chemical biocidal effects to the common effects of high temperature and pressure. Biocidal combustion products are capable of deactivating harmful spores or bacteria, which can be released by targets containing biological weapons of mass destruction. Research showed that halogens, especially iodine, are effective as biocidal components of reactive material formulations. Recently, magnesium combustion product MgO is also found to have a biocidal effect. Thus, advanced formulations containing both magnesium and iodine are of interest; such formulations are prepared and investigated here.

Reactive materials …

A New Interpretation Of The √7×√7 R19.1° Structure For P Adsorbed On A Ni(111) Surface, Elizabeth Barrow, Grant S. Seuser, Hiroko Ariga-Miwa, Donna A. Chen, Jochen A. Lauterbach, Kiyotaka Asakura

Faculty Publications

We have studied P adsorption on Ni(111), a system which shows complex adsorbate structures. We determined the phase diagram of the surface P adsorbed on Ni(111). At low coverage, amorphous P was observed. At temperatures between 373 and 673 K and coverages above 0.1 monolayer, we found a √7×√7 R19.1° structure, but above 673 K, other complex structures were created. These structures seemed to correlate with each other and we reinterpret a √7×√7 R19.1° structure of P adsorbed on Ni(111) based on the similarities of these surface structures. The new rectangular structure for the √7×√7 19.1° is discussed in relation …

Effect Of 3d Printed Tablet Shape On Drug Release Profile, Christina Gedeon

Theses

There is a growing interest in utilizing additive manufacturing (AM) as a manufacturing tool to develop oral tablets for personalized medicine. This ultimate goal in mind, this study explores the feasibility of extrusion-based fused deposition modeling (FDM) to 3D print oral tablets with tunable design to control drug release profile. Tablets are printed using poly(vinyl alcohol) (PVA) loaded with model drugs: acetaminophen and caffeine. Hot melt extrusion (HME) is used to fabricate PVA filaments loaded with acetaminophen and caffeine. These filaments are used to fabricate a range of tablets with varying designs to prepare immediate and delayed release tablets. Thermal …

Impact Of Stirrer Speed And Media Type-Loading On The Breakage Kinetics During Wet Stirred Media Milling Of Griseofulvin, Nathaniel Parker

Theses

The aim of this study is to investigate the impact of stirrer speed (2000-4000 rpm) and bead loading (~20-60%) on the breakage kinetics-energy consumption during milling of griseofulvin, a poorly soluble drug, and compare the performance of crosslinked polystyrene (CPS) beads with that of yttrium-stabilized zirconia (YSZ) beads. Laser diffraction, SEM, viscometry, and XRPD were used for characterization. A microhydrodynamic model was used to interpret the breakage kinetics. An increase in stirrer speed led to faster breakage due to more frequent and forceful CPS bead-bead collisions. Despite causing slight decrease in maximum contact pressure, an increase in CPS bead loading …

A New Interpretation Of The √7×√7 R19.1° Structure For P Adsorbed On A Ni(111) Surface, Elizabeth Barrow, Grant S. Seuser, Hiroko Ariga-Miwa, Donna A. Chen, Jochen A. Lauterbach, Kiyotaka Asakura

Faculty Publications

We have studied P adsorption on Ni(111), a system which shows complex adsorbate structures. We determined the phase diagram of the surface P adsorbed on Ni(111). At low coverage, amorphous P was observed. At temperatures between 373 and 673 K and coverages above 0.1 monolayer, we found a √7×√7 R19.1° structure, but above 673 K, other complex structures were created. These structures seemed to correlate with each other and we reinterpret a √7×√7 R19.1° structure of P adsorbed on Ni(111) based on the similarities of these surface structures. The new rectangular structure for the √7×√7 19.1° is discussed in relation …

The Potentials Of Faecal Sludge Treatment Using Local Conditioners In Tanzania: A Review, Doglas Benjamin1

Tanzania Journal of Engineering and Technology (TJET)

Worldwide, every day human beings generate millions of tons of Faecal Sludge (FS), which is rich in water, nutrients, energy, and organic compounds. Yet FS is not being managed in a way that permits us to derive value from its reuse, while at the same time, millions of farmers struggle with depleted soils and lack of water. In most of the developing countries, energy for cooking is mainly derived from cutting of trees, either as wood or charcoal. Resource recovery and reuse from FS can create livelihoods, enhance food security, support green economies, reduce waste and contribute to cost recovery …

Indonesia Natural Mineral For Heavy Metal Adsorption: A Review, Grandprix T. M. Kadja, Moh Mualliful Ilmi

Journal of Environmental Science and Sustainable Development

Indonesia has abundant mineral resources used as natural adsorbent materials for the absorption of heavy metal. Among these are natural zeolites, clay, and ashes. These natural materials showed high performance adsorption capacity with respects to their low cost and high availability. Several research reports had been published for studying the performance of the natural materials as adsorbent of several heavy metals i.e., Hg, Pb, Fe, Cd, Cr, Zn, Ni, and Cu by examining the effect of various factors, including pH, contact time, initial concentration, temperature, and dosage. Furthermore, to determine the adsorption rate, mechanism, and efficiency of natural materials in …

Transient Electrochemical Surface-Enhanced Raman Spectroscopic Study In Electrochemical Reduction Of P-Nitrothiophenol, Yun Ling, Jing Tang, Guo-Kun Liu, Cheng Zong

Journal of Electrochemistry

P-nitrothiophenol (PNTP) is one of the most common probe molecules studied by surface-enhanced Raman spectroscopy (SERS). The research in electrochemical reduction behavior of PNTP will help understanding the mechanism for the nitrobenzene reduction. In this paper, we used transient electrochemical surface-enhanced Raman spectroscopy (TEC-SERS) to study the SERS of PNTP with cyclic voltammetry and chronoamperometry on gold electrodes. The results show that the TEC-SERS provide a time resolution that equals the transient electrochemical methods, and we concluded that the reaction was so quick that we did not observe the spectral information of intermediate species described in the literatures with a …

Electrochemical Sensor Based On Magnetic Electrode Modified With Magnetic Molecularly Imprinted Nanoparticles Immobilized Hemoglobin For Determination Of Hydrogen Peroxide, Yang Yuan, Jia-Xin Wang, Yu-Hua Cao

Journal of Electrochemistry

In this work, the surface-imprinted technique was used to prepare magnetic hemoglobin (Hb) imprinted nanoparticles, using Fe₃O₄@SiO₂ NPs as the carrier, Hb as the template molecule, and tetraethyl orthosilicate (TEOS) as the imprinted polymer monomer. The nanoparticles had a core-shell structure, with magnetic Fe₃O₄ NPs as the core and Hb imprinted polymers as the shell. Therefore, Hb could be concentrated and fixed on the surface of the magnetic imprinted nanoparticles (MMIPs NPs). Furthermore, MMIPs NPs were immobilized with chitosan (CS) on the surface of a magnetic electrode to constitute Hb enzyme-like biosensor …

Zif-67-Derived Ag/Co-Embedded N-Enriched Mesoporous Carbon For Oxygen Reduction Reaction, Zheng-Ling Di, Jing Zhu, Lei Dai, Wei Meng, Yue-Hua Li, Zhang-Xing He, Ling Wang

Journal of Electrochemistry

Nitrogen-doped porous carbon materials are considered as one of the most promising catalysts for oxygen reduction reaction (ORR). Herein, in order to further improve the activity of the nitrogen-doped porous carbon, Ag/Co bimetal is embedded into nitrogendoped porous carbon to form Ag/Co-embedded nitrogen-doped porous carbon material (AgCo@NC). The AgCo@NC was derived by the wet impregnation of Ag+ into ZIF-67 precursor, followed by chemical reduction and a subsequent pyrolysis process under Ar atmosphere at different temperatures (500 ℃, 600 ℃, 700 ℃). The morphologic characterization shows that the Ag/Co nanoparticles were successfully embedded in the mesoporous carbon framework with abundant nitrogen …

Ionic Liquid Assisted Synthesis Of Porous Carbons From Rice Husk For Supercapacitors, Han-Fang Zhang, Feng Wei, Jian Sun, Meng-Ying Jing, Xiao-Jun He

Journal of Electrochemistry

It is still a challenge to prepare carbon materials with high specific surface area at low cost from renewable resources. Herein, the authors report an efficient approach to synthesize porous carbons (PCs) from rice husk with ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF₆)) as a template and an activation agent. The as-made PCs featured the high specific surface area up to 1438 m²·g^-1. As electrodes for supercapacitors, PCs showed a high specific capacitance of 256 F·g^-1 at 0.05 A·g^-1 in 6 mol·L^-1 KOH aqueous electrolyte and a good rate performance of 211 F·g …

A Microfluidic Paper-Based Analytical Device For Early Diagnosis And Prognosis Of Acute Myocardial Infarction, Lim Wei Yin

Student Works (2020-2029)

Acute myocardial infarction (AMI), also termed as heart attack, is often clinically screened by blood test through the measurement of cardiac biomarkers (i.e., troponin (T or I), creatine kinase (CK−MB) and myoglobin) and electrocardiography (ECG) changes which are presented to the hospital. However, the early diagnosis of AMI is challenging because the detection of biomarkers such as troponin (T or I) and CK−MB are only reliable at the intermediate and later stages (> 6 hours after chest pain onset), during myocardial injury and myocardial infarction. On the other hand, myoglobin often been used as early biomarker which is detectable within …

Assessing Magnetic Iron Oxide Nanoparticles Properties Under Different Thermal Treatments, Erick S. Vasquez, Evan M. Prehn, Keisha B. Walters

Chemical and Materials Engineering Faculty Publications

Magnetic nanoparticle structures have been examined as potential carrier vehicles and substrates in a wide range of applications where they undergo mechanical, chemical and/or thermal manipulation to allow for their modification, conjugation and transport. For safe and effective use, it is imperative to not only measure the initial physicochemical and structural properties of nanomaterials, but also identify and quantify any property changes related to a loss of chemical and/or physical integrity during processing and usage conditions. In this study an assessment of iron oxide magnetic nanoparticle thermal stability using modulated differential scanning calorimetry (mDSC) and a controlled-heating system is conducted …

Design And Development Of A Perfusion Bioreactor With Internal Volume Expansion And Cell Retention For Cell And Gene Therapy Manufacturing, Corinna Doris

KGI Theses and Dissertations

Economically producing patient-specific cell therapies at commercial levels remains a challenge as it requires manufacturing separate batches per patient where the production system must be scaled-out rather than scaled-up to supply more patient doses. The resulting high production cost and consequent price-point can limit patient access. Specifically, the current cell expansion processes are highly manual and laborious, with the number and complexity of operations and components increasing the opportunities for failure and contamination. This work therefore aims to design a mechanically simple bioreactor that is better suited for scale-out by consolidating the cell expansion process to fewer components, vessels, and …

Electroanalytical Investigation Of The Electrode –Electrolyte Interface Of Quaternary Ammonium Ionic Liquids: Impact Of Alkyl Chain Length And Ether Functionality, Jeffrey M. Klein, Henry Squire, Burcu E. Gurkan

Faculty Scholarship

The influence of ionic associations and potential-dependent interactions on the electrode-electrolyte interfacial structure of ionic liquids (ILs) is studied by electrochemical impedance spectroscopy (EIS) and surface-enhanced Raman spectroscopy (SERS) for a variety of asymmetric quaternary ammonium ILs. Specifically, the impact of cation alkyl chain length (C = 4, 8 and 16) and ether functionality on the interfacial structuring of ILs at the glassy carbon electrode surface is examined. Ammonium cations with alkyl chain length of 8 and 16 carbons are found to stabilize the formation of the bis(trifluorosulfonyl)imide, [TFSI], anion dense Stern layer at positive electrode potentials leading to larger …

Fluorinated Coal Derived Carbons And Electrodes For Use In Battery Systems And Similar, Stephen M. Lipka, Christopher R. Swartz

Center for Applied Energy Research Faculty Patents

An electrode including fluorinated and surface defluorinated coal is described, as well as methods of producing such and employing such within an electrical system. The coal in the electrodes is fluorinated at an amount of between 0.3 and 1 .4. The resulting coal products can be further surface defluorinated and maintain functionality within an electrical system.

Low Temperature Liquid Metal Batteries For Energy Storage Applications, Cameron A. Lippert, Kunlei Liu, James Landon, Susan A. Odom, Nicolas E. Holubowitch

Center for Applied Energy Research Faculty Patents

The present invention relates to a molten metal battery of liquid bismuth and liquid tin electrodes and a eutectic electrolyte. The electrodes may be coaxial and coplanar. The eutectic electrolyte may be in contact with a surface of each electrode. The eutectic electrolyte may comprise ZnC1₂:KCI.

Corrosion-Resistant Non-Carbon Electrocatalyst Supports For Proton Exchange Membrane Fuel Cells, Cheng He

McKelvey School of Engineering Graduate Student Theses & Dissertations

Proton exchange membrane fuel cells (PEMFCs) are a promising portable power source due to their low operating temperature, minimal pollutant generation and fast startup. However, several challenges remain concerning lifetime, reliability, and cost. A critical issue is PEMFC component durability. Platinum supported on high surface area carbon has been one of the most widely used electrocatalysts in PEMFCs. However, carbon corrosion over the course of normal PEMFC operation occurs due to the relatively low standard electrode potential for the carbon dioxide/carbon redox couple (0.207V vs. standard hydrogen electrode). Considering this challenge, it is imperative to identify alternative support materials to …

Contemporary Problems In Aerosol Aggregation And Gelation, Pai Liu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Aggregation of nanoparticles in aerosols is a fundamental phenomenon with important implications to diverse fields ranging from material synthesis to pollutant control. The past few decades have witnessed extensive research on investigating the structure and growth mechanism of aerosol aggregates with sizes spanning across several orders of magnitude. This dissertation focuses on some contemporary problems that remain unaddressed in this topical area. Aerosol aggregates in sub-micron regimes, which are formed via the irreversible collision and aggregation of solid nanoparticle monomers, are fractal-like in their morphology. A mathematical description of this seemingly random structure dates to the seminal works by Forest …

Coulombic And Non-Coulombic Effects Of Single And Overlapping Electric Double Layers With Surface Charge Regulation, Raviteja Vangara

Chemical and Biological Engineering ETDs

The physical origin of charged interfaces involving electrolyte solutions is in the thermodynamic equilibrium between the surface reactive groups and certain dissolved ionic species in the bulk. This equilibrium is very strongly dependent on the precise local density of these species, also known as potential determining ions in the solution. The latter, however, is determined by the overall solution structure, which is dominated by the large number of solvent molecules relative to all solutes. Hence, the solvent contribution to the molecular structure is a crucial factor that determines the properties of electric double layers. Models that explicitly account for the …

Cfd Simulation Investigating The Effects Of Groove Geometry On Heat Transfer For Internally Grooved Tubes, Richard Zaven Saroukhanoff

UNLV Theses, Dissertations, Professional Papers, and Capstones

This numerical study investigates the thermal performance of internally grooved tubes used in heat exchangers. In order to enhance the performance of heat exchangers, turbulence promoters are inserted along the streamwise flow. The use of inserts, grooves, and augmentations along the axial length of the tube creates disturbances that improve the overall heat transfer due to enhanced fluid mixing and greater surface contact boundary walls. However, the implementation of tube wall augmentations creates an increase in pressure drop across the tube which must be compensated for with additional pumping power for the working fluid. Therefore, in order to analyze the …

Performance Modeling Of Supercritical Carbon Dioxide Zigzag-Channel Printed Circuit Heat Exchangers, Katrine Birgitte Bennett

UNLV Theses, Dissertations, Professional Papers, and Capstones

Supercritical carbon dioxide (sCO2) is currently being studied as the working fluid in power producing Brayton cycles due to its excellent physical and thermodynamic properties, especially near the critical point. Printed circuit heat exchangers (PCHEs) are being considered for use as condensers and recuperators for this purpose due to their high strength and compact designs. Many experimental and numerical studies are being conducted to characterize and optimize sCO2 PCHE operation and develop correlations to describe their thermal-hydraulic performance. Additionally, a few experimental and numerical structural assessments of these PCHEs have been conducted, but all have been somewhat limited due to …

The Role Of Multi-Charged Responses: Construction And Application Of A Tandem Differential Mobility Analyzer (Tdma), Christopher Ray Oxford

McKelvey School of Engineering Graduate Student Theses & Dissertations

Atmospheric aerosols impact health outcomes, visibility, and the energy balance of the earth. The atmosphere contains a variety of compounds, and the volatility (phase change enthalpy and vapor pressure) of each compound determines its partitioning between the gas phase and the particle phase. The hygroscopicity (an aerosol’s affinity for water) of an atmospheric aerosol particle is determined by the many compounds present in the particle, and thus, the volatility impacts hygroscopicity. Changes in hygroscopicity alter the fraction of the aerosol deposited in the lungs and the fraction of the aerosol activated into cloud droplets. Thus, understanding the volatility and hygroscopicity …