Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

University of Arkansas, Fayetteville

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 511 - 540 of 2839

Full-Text Articles in Engineering

An Annotated Checklist Of The Camel Crickets (Insecta: Orthoptera: Rhaphidophoridae) Of Arkansas, H.W. Robison, C.T. Mcallister Jan 2024

An Annotated Checklist Of The Camel Crickets (Insecta: Orthoptera: Rhaphidophoridae) Of Arkansas, H.W. Robison, C.T. Mcallister

Journal of the Arkansas Academy of Science

A total of 14 native species of camel crickets and one introduced taxon representing three genera (Ceuthophilus, Phrixocnemis, and Diestrammena) of the orthopteran family Rhaphidophoridae, are herein reported from Arkansas. The most diverse genus was Ceuthophilus, with 13 native species, while Phrixocnemis had one native species, and Diestrammena, formerly Tachycines, was represented by one introduced species. This updated checklist is intended to be of use to entomologists, naturalists, professional biologists, and resource managers in evaluating the biodiversity of Arkansas. State distributional maps are provided for each species listed by county, and habitats are discussed in which each species was taken …


Fish Leeches Of Arkansas, D.J. Richardson, W.E. Moser, C.T. Mcallister, S.P. Lawson, H.W. Robison Jan 2024

Fish Leeches Of Arkansas, D.J. Richardson, W.E. Moser, C.T. Mcallister, S.P. Lawson, H.W. Robison

Journal of the Arkansas Academy of Science

Recent collection within Arkansas greatly enlarges the knowledge concerning hosts and distributions of fish leeches within the state. The natural history of the 6 species of fish leeches known from Arkansas (Placobdella montifera, Placobdella pediculata, Cystobranchus klemmi, Cystobranchus verrilli, Myzobdella lugubris, and Myzobdella reducta) is reviewed and updated and molecular data are provided.


Aggregation And Oligomerization Characterization Of Ss-Lactoglobulin Protein Using A Solid-State Nanopore Sensor, Mitu C. Acharjee, Brad Ledden, Brian Thomas, Xianglan He, Troy Messina, Jason Giurleo, David Talaga, Jiali Li Jan 2024

Aggregation And Oligomerization Characterization Of Ss-Lactoglobulin Protein Using A Solid-State Nanopore Sensor, Mitu C. Acharjee, Brad Ledden, Brian Thomas, Xianglan He, Troy Messina, Jason Giurleo, David Talaga, Jiali Li

Physics Faculty Publications and Presentations

Protein aggregation is linked to many chronic and devastating neurodegenerative human diseases and is strongly associated with aging. This work demonstrates that protein aggregation and oligomerization can be evaluated by a solid-state nanopore method at the single molecule level. A silicon nitride nanopore sensor was used to characterize both the amyloidogenic and native-state oligomerization of a model protein ß-lactoglobulin variant A (βLGa). The findings from the nanopore measurements are validated against atomic force microscopy (AFM) and dynamic light scattering (DLS) data, comparing βLGa aggregation from the same samples at various stages. By calibrating with linear and circular dsDNA, this study …


Pleated Plasma Membrane Complex In Spermatids Of The Western Siren, Siren Nettingi (Caudata: Sirenidae), S.E. Trauth Jan 2024

Pleated Plasma Membrane Complex In Spermatids Of The Western Siren, Siren Nettingi (Caudata: Sirenidae), S.E. Trauth

Journal of the Arkansas Academy of Science

I investigated the pleated plasma membrane complex of linear folds and biflagellar entities in developing spermatids of the Western Siren, Siren nettingi. My primary goal was to reveal the ultrastructural morphology of these distinctive cellular folds (usually 8 in number) as they support the flagellar formation of biflagellated sperm found in this salamander and in other members in the family Sirenidae. My results reveal that the biflagellar components (2 sets of axonemes, undulating membranes, and axial fibers), termed biflagellar complex, develop between folds or are attached onto these folds. The folds themselves are transitory and do not directly contribute to …


A Survey Of Strongyle Nematodes In New England Dairy Goats, D.J. Richardson, E.M. Wray, D. Watters, U. Hanif, E. Jalbert, E. Thompson, G. Trajkovic, A.R. Sirois, N. Pilotte Jan 2024

A Survey Of Strongyle Nematodes In New England Dairy Goats, D.J. Richardson, E.M. Wray, D. Watters, U. Hanif, E. Jalbert, E. Thompson, G. Trajkovic, A.R. Sirois, N. Pilotte

Journal of the Arkansas Academy of Science

The paucity of information concerning the occurrence of strongyle nematodes in New England dairy goats prompted a survey of 241 dairy goats from throughout New England. Of the 241 goats examined using the McMaster technique, 104 (42.7%) were infected with strongyles with a mean intensity (+ SE) of 369.7 + 45.8 eggs per gram. Subsequent molecular examination of 50 random samples from these goats revealed a prevalence of 88% infection specifically with Haemonchus contortus. Haemonchus contortus is the most important internal parasite of sheep and goats, exerting a crushing economic burden on the livestock industry worldwide due to lowered milk …


A Simple, Inexpensive Alkaline Method For Bacterial Dna Extraction From Environmental Samples For Pcr Surveillance And Microbiome Analyses, Abdulkarim Shwani, Bin Zuo, Adnan Alrubaye, Jiangchao Zhao, Douglas D. Rhoads Jan 2024

A Simple, Inexpensive Alkaline Method For Bacterial Dna Extraction From Environmental Samples For Pcr Surveillance And Microbiome Analyses, Abdulkarim Shwani, Bin Zuo, Adnan Alrubaye, Jiangchao Zhao, Douglas D. Rhoads

Poultry Science Faculty Publications and Presentations

DNA extraction for downstream molecular diagnostic applications can be an expensive, time-consuming process. We devised a method to quickly extract total bacterial DNA from environmental samples based on the sodium hydroxide lysis of cells with or without capture by magnetic beads for subsequent PCR or quantitative PCR. The final DNA extraction method using NaOH is extremely low-cost and can be completed in as little as 10 min at room temperature with dilution, or the DNA can be further purified using silica-coated paramagnetic beads. NaOH extraction was effective for Gram-negative and Gram-positive bacteria in samples from air, soil, sewage, food, laboratory …


Bat Versus Ant: The First Report Of Evening Bat/Ant Interaction In Arkansas, J.D. Wilhide, D.B. Sasse, R.P. Kelso Jan 2024

Bat Versus Ant: The First Report Of Evening Bat/Ant Interaction In Arkansas, J.D. Wilhide, D.B. Sasse, R.P. Kelso

Journal of the Arkansas Academy of Science

This paper documents the first reported occurrence of bat/ant agonistic interaction in Arkansas and the second report involving Evening Bats (Nycticeius humeralis). An adult male Evening Bat was captured during a presence / absence mist net survey along Highway 412 in Black Rock, Lawrence County, Arkansas on 4 June 2023. The bat weighed 12.0 g and had a forearm length of 36.94 mm which is in the midrange for evening bats in Arkansas (Sealander and Heidt 1990). The evening bat had two ant head capsules attached to its right cheek and at the tip of the lower lip (Fig. 1).


Keynote Address And Meeting Program, Academy Editors Jan 2024

Keynote Address And Meeting Program, Academy Editors

Journal of the Arkansas Academy of Science

No abstract provided.


Journal Acknowledgements And Editorial Board, Academy Editors Jan 2024

Journal Acknowledgements And Editorial Board, Academy Editors

Journal of the Arkansas Academy of Science

No abstract provided.


Instructions To Authors, Academy Editors Jan 2024

Instructions To Authors, Academy Editors

Journal of the Arkansas Academy of Science

No abstract provided.


Distal Urogenital Anatomy And Epithelial Morphology In The Male Cajun Chorus Frog, Pseudacris Fouquettei (Anura: Hylidae), S.E. Trauth Jan 2024

Distal Urogenital Anatomy And Epithelial Morphology In The Male Cajun Chorus Frog, Pseudacris Fouquettei (Anura: Hylidae), S.E. Trauth

Journal of the Arkansas Academy of Science

I examined the microanatomy of the distal urogenital system in male Cajun Chorus Frogs (Pseudacris fouquettei) from a small sample (n = 6) collected in central Arkansas in March 2018 and February 2023. Specifically, my primary objectives were to investigate the following: (1) the paired Wolffian (urogenital) ducts caudally from the kidneys to their merging with the urodeum of the cloaca, (2) the structure of seminal vesicles (if present), and (3) the epithelial morphologies among the distal urogenital tract, the posterior alimentary canal, and cloaca. My histological analysis confirmed the presence of ampullae (sperm storage structures) as mid-duct expansions of …


Use Of Google Earth Streetview To Evaluate Nesting By The Cliff Swallow (Petrochelidon Pyrrhonota) In Lowlands Of Eastern Arkansas, With Reports Of New Records, R. Tumlison, Z. Autrey Jan 2024

Use Of Google Earth Streetview To Evaluate Nesting By The Cliff Swallow (Petrochelidon Pyrrhonota) In Lowlands Of Eastern Arkansas, With Reports Of New Records, R. Tumlison, Z. Autrey

Journal of the Arkansas Academy of Science

Cliff Swallows (Petrochelidon pyrrhonota) typically construct their mud nests under the overhangs of cliffs. However, construction of concrete bridges and overpasses has provided suitable nesting structure in the last few decades. As the number of such nesting sites have increased, the breeding range also has expanded. We evaluated the use of Google Earth Streetview as a means of cheaply harvesting data regarding nesting distribution. The gourd-shaped nests of Cliff Swallows were easily discernible via available imagery, and we were able to document previously unreported nest sites of this species in 6 counties in eastern Arkansas (5 from imagery, 1 from …


Shell Damage Patterns In Limpkin Mussel Middens At Bois D’Arc Lake, Arkansas, G.R. Graves Jan 2024

Shell Damage Patterns In Limpkin Mussel Middens At Bois D’Arc Lake, Arkansas, G.R. Graves

Journal of the Arkansas Academy of Science

The Limpkin (Aramus guarauna) is rapidly colonizing the lower Mississippi Valley from recently established Gulf Coast populations. Anecdotal reports indicate that it feeds on freshwater mussels and gastropods in Arkansas, but without documentation. Here I report an analysis of Limpkin shell middens from Bois d’Arc Lake in Hempstead Co. Limpkins at this location preyed heavily on Pyganodon grandis (Giant Floater), a large mussel species widely distributed in the Mississippi Valley. Limpkins employ vigorous bill blows to pierce holes in mussels and usually attack the anterior end of the shell. Video and photographs of feeding birds provide new insight on the …


Rapid Expansion Of The Limpkin Aramus Guarauna Across Anglo-America, A. Alam, R. Kaddoura, J. Jackson, R. Kannan Jan 2024

Rapid Expansion Of The Limpkin Aramus Guarauna Across Anglo-America, A. Alam, R. Kaddoura, J. Jackson, R. Kannan

Journal of the Arkansas Academy of Science

We quantitatively document and describe the recent rapid expansion of the Limpkin Aramus guarauna across Anglo-America (United States and Canada). Using data downloaded from eBird (www.eBird.org), we present graphs showing the explosive growth in reports of number of individual birds and frequencies in checklists for this species in several parts of Anglo- America outside Florida (its traditional Anglo- American range). We also provide geographic progression maps to illustrate the expansion through time (2013-2023) and furnish qualitative information on foods consumed by the bird in new areas, based on a survey of 274 images uploaded by citizen scientists in eBird. Possible …


X-Ray Diffraction And Petrographic Analysis Of Magnet Cove Carbonatite Core, Arkansas, R.E. Mero, D. Mayo, M.P. Testa Jan 2024

X-Ray Diffraction And Petrographic Analysis Of Magnet Cove Carbonatite Core, Arkansas, R.E. Mero, D. Mayo, M.P. Testa

Journal of the Arkansas Academy of Science

Geothermal activity such as hot springs are known to precipitate calcium carbonate (CaCO3) minerals, producing rocks such as tufa, travertine and sometimes associated with carbonatite. The precipitation of CaCO is caused by the reduction of CO, which is less soluble in warmer waters. Geothermal heating of water in natural springs drives this precipitation of CaCO3 in areas of Arkansas including Magnet Cove. Magnet Cove, Arkansas is an alkalic igneous rock complex that is composed of a series of ring dikes post-Mississippian in age. These dikes have intruded into faulted and folded Paleozoic sedimentary rocks. One of these igneous dikes is …


New Record Of Leucistic Blue Catfish, Ictalurus Furcatus (Siluriformes: Ictaluridae) From The Black River, Lawrence County, Arkansas, C.T. Mcallister, H.W. Robison Jan 2024

New Record Of Leucistic Blue Catfish, Ictalurus Furcatus (Siluriformes: Ictaluridae) From The Black River, Lawrence County, Arkansas, C.T. Mcallister, H.W. Robison

Journal of the Arkansas Academy of Science

The Blue Catfish, Ictalurus furcatus (Lesueur), the largest North American ictalurid, inhabits deep watersheds, impoundments, and main channels and backwaters of medium to large rivers, over mud, sand, and gravelly substrate. Its native range includes the Mississippi River basin from western Pennsylvania to southern South Dakota and southwestern Nebraska south to the Gulf of Mexico and in Alabama, Florida, The Rio Grande drainage of Texas and New Mexico (Page and Burr 2011). In Arkansas, I. furcatus is found throughout the Arkansas, Red, and Mississippi river drainages and has been stocked by the Arkansas Game and Fish Commission into reservoirs throughout …


Ltspice Modeling For Gan-Git Hemt Including Cryogenic Temperature, Md Maksudul Hossain, Yuqi Wei, H. Alan Mantooth Jan 2024

Ltspice Modeling For Gan-Git Hemt Including Cryogenic Temperature, Md Maksudul Hossain, Yuqi Wei, H. Alan Mantooth

Electrical Engineering Faculty Publications and Presentations

Highly efficient electrically driven avionics have led to a renewed interest in cryogenic propulsion systems with the goal of reducing carbon emission footprint. Although cryogenic converters promise better efficiency and improved power density, the successful design is incumbent upon the appropriate switching device selection and simulation-based analyses prior to initial prototyping. In this work, a datasheet-driven compact model for a gallium nitride (GaN) Gate Injection Transistor (GIT) has been proposed and implemented in LTspice, a versatile, high performance, and free circuit simulator in order to investigate the merit of the chosen device in a power electronic system.


Gan Hemt And Air Core Magnetics Based Power Converters Evaluations At Cryogenic Temperature, Yuqi Wei, Md Maksudul Hossain, H. Alan Mantooth Jan 2024

Gan Hemt And Air Core Magnetics Based Power Converters Evaluations At Cryogenic Temperature, Yuqi Wei, Md Maksudul Hossain, H. Alan Mantooth

Electrical Engineering Faculty Publications and Presentations

Cryogenic power electronics is both advantageous and indispensable in many applications, like deep space probe, military electric vehicle, magnetic resonance imaging etc. Among different semiconductors, the gallium nitride (GaN) high electron mobility transistor (HEMT) is the most promising candidate for cryogenic applications with significant conduction loss and switching loss reductions. Moreover, there is no carrier freeze out effect for the GaN HEMTs, which is applicable in extreme low temperature operating conditions. In this work, the efficiency of GaN HEMTs based power converters with different power levels (from several Watts to several kiloWatts) are evaluated at cryogenic temperature. Three different commercial …


Closing Dichloramine Decomposition Nitrogen And Oxygen Mass Balances: Relative Importance Of End-Products From The Reactive Nitrogen Species Pathway, Huong T. Pham, David G. Wahman, Julian L. Fairey Jan 2024

Closing Dichloramine Decomposition Nitrogen And Oxygen Mass Balances: Relative Importance Of End-Products From The Reactive Nitrogen Species Pathway, Huong T. Pham, David G. Wahman, Julian L. Fairey

Civil Engineering Faculty Publications and Presentations

In drinking water chloramination, monochloramine autodecomposition occurs in the presence of excess free ammonia through dichloramine, the decay of which was implicated in N-nitrosodimethylamine (NDMA) formation by (i) dichloramine hydrolysis to nitroxyl which reacts with itself to nitrous oxide (N2O), (ii) nitroxyl reaction with dissolved oxygen (DO) to peroxynitrite or mono/dichloramine to nitrogen gas (N2), and (iii) peroxynitrite reaction with total dimethylamine (TOTDMA) to NDMA or decomposition to nitrite/nitrate. Here, the yields of nitrogen and oxygen-containing end-products were quantified at pH 9 from NHCl2 decomposition at 200, 400, or 800 μeq Cl2·L …


Enhancing Microwave Disinfection: Impact Of Sodium Chloride On Microbial Inactivation, Saleh A. Alfawaz, Ibrahim Nasser I. Alquaydheb, Amirreza Ghadimi Avval, Sara Ghayouraneh, Samir M. El-Ghazaly, Jianhong Zhou Jan 2024

Enhancing Microwave Disinfection: Impact Of Sodium Chloride On Microbial Inactivation, Saleh A. Alfawaz, Ibrahim Nasser I. Alquaydheb, Amirreza Ghadimi Avval, Sara Ghayouraneh, Samir M. El-Ghazaly, Jianhong Zhou

Electrical Engineering and Computer Science Faculty Publications and Presentations

This study explores the role of sodium chloride (NaCl) in enhancing the efficiency of microbial inactivation using microwave energy with two distinct methods: temperature-controlled treatment and predefined cycle. The primary objective is to maintain a stable temperature within the biological samples during treatment. Detailed descriptions of the treatment system’s design and the function of each element are provided. Simulations are conducted to illustrate the heating behavior of liquids with and without NaCl, revealing significant differences in temperature profiles between the two media. The experimental design and the objective behind each iteration are discussed. The experimental design includes three different power …


Theoretical Investigations Of The Structural, Dynamical, Electronic, Magnetic, And Thermoelectric Properties Of CoMRhsi (M = Cr, Mn) Quaternary Heusler Alloys, Abdullah Hzzazi, Hind Alqurashi, Eesha Andharia, Bothina Hamad, M. O. Manasreh Jan 2024

Theoretical Investigations Of The Structural, Dynamical, Electronic, Magnetic, And Thermoelectric Properties Of CoMRhsi (M = Cr, Mn) Quaternary Heusler Alloys, Abdullah Hzzazi, Hind Alqurashi, Eesha Andharia, Bothina Hamad, M. O. Manasreh

Physics Faculty Publications and Presentations

The structural, dynamical, electrical, magnetic, and thermoelectric properties of CoMRhSi (M = Cr, Mn) quaternary Heusler alloys (QHAs) were investigated using density functional theory (DFT). The Y-type-II crystal structure was found to be the most stable configuration for these QHAs. Both CoCrRhSi and CoMnRhSi alloys possess a half-metallic behavior with a 100% spin-polarization as the majority spin channel is metallic. On the other hand, the minority spin channel is semiconducting with narrow indirect band gaps of 0.54 eV and 0.57 eV, respectively, along the Γ−𝑋 high symmetry line. In addition, both CoCrRhSi and CoMnRhSi alloys possess a ferromagnetic structure …


Effect Of Strain Profiling On Anisotropic Opto-Electronic Properties Of As2X3 (X =S, Te) Monolayers From First Principles, Eesha Andharia, Hind Alqurashi, Ihsan Erikat, Bothina Hamad, M. O. Manasreh Jan 2024

Effect Of Strain Profiling On Anisotropic Opto-Electronic Properties Of As2X3 (X =S, Te) Monolayers From First Principles, Eesha Andharia, Hind Alqurashi, Ihsan Erikat, Bothina Hamad, M. O. Manasreh

Physics Faculty Publications and Presentations

Strain Engineering is a widely adopted approach to modulate the opto-electronic performance of 2-Dimensional (2D) materials. Recently, anisotropic Van der Waals (vdW) based 2D As2S3 monolayer has gained significant attention within the scientific community due to its stability in ambient conditions. Similar compounds like As2Te3 have also been theoretically explored. However, its indirect bandgap nature limits its application in optical devices. In this study, a systematic study of compressive and tensile strain on three profiles–Uniaxial along a-axis, Uniaxial along b-axis and biaxial strain from −10% to +10%, is performed for As2S3 …


In Vivo Measurement Of Nadh Fluorescence Lifetime In Skeletal Muscle Via Fiber-Coupled Time-Correlated Single Photon Counting, Kathryn M. Priest, Jacob V. Schluns, Nathania Nischal, Colton L. Gattis, Jeffery C. Wolchok, Timothy J. Muldoon Jan 2024

In Vivo Measurement Of Nadh Fluorescence Lifetime In Skeletal Muscle Via Fiber-Coupled Time-Correlated Single Photon Counting, Kathryn M. Priest, Jacob V. Schluns, Nathania Nischal, Colton L. Gattis, Jeffery C. Wolchok, Timothy J. Muldoon

Biomedical Engineering Faculty Publications and Presentations

Nicotinamide adenine dinucleotide (NADH) is a cofactor that serves to shuttle electrons during metabolic processes such as glycolysis, the tricarboxylic acid cycle, and oxidative phosphorylation (OXPHOS). NADH is autofluorescent, and its fluorescence lifetime can be used to infer metabolic dynamics in living cells. Fiber-coupled time-correlated single photon counting (TCSPC) equipped with an implantable needle probe can be used to measure NADH lifetime in vivo, enabling investigation of changing metabolic demand during muscle contraction or tissue regeneration. This study illustrates a proof of concept for point-based, minimally-invasive NADH fluorescence lifetime measurement in vivo. Volumetric muscle loss (VML) injuries were …


Recovery Of Ionic Liquid From The Model Solution Mixture Mimicking The Catalytically Hydrolyzed Cellulose Product Utilizing Amberlyst Ion-Exchange Resin, Chhabilal Regmi, Chidambaram Thamariselvan, Zhexi Zhu, Xianghong Qian, S. Ranil Wickramasinghe Jan 2024

Recovery Of Ionic Liquid From The Model Solution Mixture Mimicking The Catalytically Hydrolyzed Cellulose Product Utilizing Amberlyst Ion-Exchange Resin, Chhabilal Regmi, Chidambaram Thamariselvan, Zhexi Zhu, Xianghong Qian, S. Ranil Wickramasinghe

Chemical Engineering Faculty Publications and Presentations

The hydrolysis of cellulose using ionic liquid (IL) has been extensively studied but there is limited understanding of the removal of IL from the biomass hydrolysate. Finding a suitable method for the recovery and reuse of IL is one of the biggest challenges before its large-scale application. Selecting an appropriate combined recovery process is very important. This study proposed a facile ion-exchange combined method for the recovery of IL from the modeled cellulose hydrolysate mixture containing sugars as well as γ-valerolactone (GVL) via an adsorption–desorption mechanism using sulfonic acid cation-exchange (Amberlyst 15 (H)) resin. The results showed that the resin …


Energy Content Of Acorns Of Shinnery Oak (Quercus Havardii) In The Diet Of Scaled Quail (Callipepla Squamata) In Southeastern New Mexico, J.L. Hunt, M.E. Grilliot, T.L. Best, D. Lozano-Lopez, E.R. Neilson, I.C. Castillo Jan 2024

Energy Content Of Acorns Of Shinnery Oak (Quercus Havardii) In The Diet Of Scaled Quail (Callipepla Squamata) In Southeastern New Mexico, J.L. Hunt, M.E. Grilliot, T.L. Best, D. Lozano-Lopez, E.R. Neilson, I.C. Castillo

Journal of the Arkansas Academy of Science

Shinnery oak (Quercus havardii) is a deciduous, low-growing shrubby tree that is a dominant plant in large areas of grassland in western Oklahoma, the Texas Panhandle, and eastern New Mexico. Acorns of the plant are important food items for many wildlife species, including scaled quail (Callipepla squamata), mourning doves (Zenaida macroura), and endangered lesser prairie-chickens (Tympanuchus pallidicinctus). We analyzed the energy content of acorns of shinnery oak obtained from the crops of scaled quail collected from plains-mesa sand-scrub in Lea and Eddy counties, New Mexico. Acorns were removed from crops and dried for 48 hours at 60°C to remove moisture …


Cybersecurity In Critical Infrastructure Systems: Emulated Protection Relay, Mitchell Bylak Dec 2023

Cybersecurity In Critical Infrastructure Systems: Emulated Protection Relay, Mitchell Bylak

Computer Science and Computer Engineering Undergraduate Honors Theses

Cyber-attacks on Critical Systems Infrastructure have been steadily increasing across the world as the capabilities of and reliance on technology have grown throughout the 21st century, and despite the influx of new cybersecurity practices and technologies, the industry faces challenges in its cooperation between the government that regulates law practices and the private sector that owns and operates critical infrastructure and security, which has directly led to an absence of eas- ily accessible information and learning resources on cybersecurity for use in public environments and educational settings. This honors research thesis addresses these challenges by submitting the development of an …


Ionically Crosslinked Cellulose Nanocrystals By Metal Nitrates For The Preparation Of Stable Emulsions With Tunable Interface Properties, Joseph Batta-Mpouma, Gurshagan Kandhola, Jin-Woo Kim Dec 2023

Ionically Crosslinked Cellulose Nanocrystals By Metal Nitrates For The Preparation Of Stable Emulsions With Tunable Interface Properties, Joseph Batta-Mpouma, Gurshagan Kandhola, Jin-Woo Kim

Materials Science and Engineering Faculty Publications and Presentations

Biologically extracted cellulose nanocrystals (CNCs) are rod-like and amphiphilic materials with surface-exposed (hydrophilic sites) and hidden (hydrophobic sites) hydroxyl groups. These physicochemical characteristics make CNCs suitable for use as emulsifying agents to stabilize emulsions. Stable oil-in-water emulsions, using sulfated (i.e., – SO3−) CNCs that were ionically crosslinked with alkaline-earth (i.e., Mg 2+) or transition-d-block (i.e., Zn 2+) metal cations, were developed without the use of any synthetic surfactants or prior functionalization of pure CNCs with hydrophobic molecules. Various emulsion surface properties such as interfacial tension, surface charge, surface chemistry, as well as rheology were characterized. Ionically …


Enhancing Rubber (Hevea Brasiliensis) Seed Shell Biochar Through Acid-Base Modification For Effective Phenol Removal From Aqueous Environments, Oyinlola R. Obanla, Jamie A. Hestekin, Modupe E. Ojewumi, Imen Bousrih, Modupeoluwa C. Fawole Dec 2023

Enhancing Rubber (Hevea Brasiliensis) Seed Shell Biochar Through Acid-Base Modification For Effective Phenol Removal From Aqueous Environments, Oyinlola R. Obanla, Jamie A. Hestekin, Modupe E. Ojewumi, Imen Bousrih, Modupeoluwa C. Fawole

Chemical Engineering Faculty Publications and Presentations

This work encompasses using acid-base modified rubber seed shell biochar (RSSB) as an adsorption approach to eradicate phenol from aqueous mediums. Potassium hydroxide (KOH) was used pre-pyrolysis to modify the RSS, and hydrochloric acid (HCl) was used post-pyrolysis to modify the RSSB. The methodology was divided into three stages: RSS pretreatment, RSS base-modification and pyrolysis, and RSSB acid-modification and processing. Temperature, pH and several other factors were investigated for their impacts on the adsorbent, and optimal conditions were established at pH 6, 1.0 g of rubber seed shell biochar (RSSB), 50 mg/L initial concentration, 120 min contact time, and 30°C …


A Low-Power Analog Cell For Implementing Spiking Neural Networks In 65 Nm Cmos, John S. Venker, Luke Vincent, Jeff Dix Dec 2023

A Low-Power Analog Cell For Implementing Spiking Neural Networks In 65 Nm Cmos, John S. Venker, Luke Vincent, Jeff Dix

Computer Science and Computer Engineering Faculty Publications and Presentations

A Spiking Neural Network (SNN) is realized within a 65 nm CMOS process to demonstrate the feasibility of its constituent cells. Analog hardware neural networks have shown improved energy efficiency in edge computing for real-time-inference applications, such as speech recognition. The proposed network uses a leaky integrate and fire neuron scheme for computation, interleaved with a Spike Timing Dependent Plasticity (STDP) circuit for implementing synaptic-like weights. The low-power, asynchronous analog neurons and synapses are tailored for the VLSI environment needed to effectively make use of hardware SSN systems. To demonstrate functionality, a feedforward Spiking Neural Network composed of two layers, …


Capabilities Of Sintered Silver As A High Temperature Packaging Material, Bakhtiyar Mohammad Nafis Dec 2023

Capabilities Of Sintered Silver As A High Temperature Packaging Material, Bakhtiyar Mohammad Nafis

Graduate Theses and Dissertations

With electrification progressing across many sectors including industry, automotive and aerospace, the power density requirements are changing. The increased power density results in higher and higher ambient temperatures that electronics are exposed to. The response has been to move towards wide bandgap (WBG) semiconductor devices that can withstand much greater temperatures and can operate at much higher voltages than silicon. Additionally, these WBG devices deliver low drain-source on resistance (RDS_on) capabilities, enabling high current power modules that increase power density even further. This also requires the packaging to evolve in order to withstand the new requirements. As a result, researchers …