Engineering Commons^™

Insight Into The Effects Of Cation Disorder And Surface Chemical Residues On The Initial Coulombic Efficiency Of Layered Oxide Cathode, Jin-Li Liu, Han-Feng Wu, Zhi-Bei Liu, Ying-Qiang Wu, Li Wang, Feng-Li Bei, Xiang-Ming He

Journal of Electrochemistry

Lithium layered oxide LiNi_0.6Co_0.2Mn_0.2O₂ (NCM622) is one of the most promising cathode materials in high-energy lithium-ion batteries for electric vehicles. However, one drawback for NCM622 is that its initial coulombic efficiency (ICE) is only about 87%, which is at least 6% lower than that of LiCoO₂ or LiFePO₄. In this work, we investigated the effects of surface chemical residues (e.g., LiOH and Li₂CO₃) and Li/Ni cation disorder resulted during the sintering on the ICE. We found that the ICE of the as-prepared samples could be boosted …

Effectiveness Of Clay Nanotube Blended Coating Materials For Thermal Insulation, Hawa Hashm

Doctoral Dissertations

Studies conducted by the U.S. Department of Energy reported that heating and cooling systems use nearly 60% of the total energy consumed in a building, while approximately 31% of that energy loss occurs through the improperly insulated floor, walls, and ceiling. Hot summers or severely cold weather can make these problems worse. The passing of conditioned air through these building materials is a substantial source of energy loss, which has driven significant investigation into new environmentally friendly, sustainable, and cost-effective solutions. The main objective of the research was to experimentally evaluate the thermal conductivity of paints blended with halloysite nanotubes …

Recent Progress In Two Dimensional Mxenes For Photocatalysis: A Critical Review, Tahir Haneef, Kashif Rasool, Jibran Iqbal, Rab Nawaz, Muhammad Raza Ul Mustafa, Khaled A Mahmoud, Tapati Sarkar, Asif Shahzad

All Works

Transition metal carbides and nitrides, generally known as MXenes have emerged as an alternative to improve photocatalytic performance in renewable energy and environmental remediation applications because of their high surface area, tunable chemistry, and easily adjustable elemental compositions. MXenes have many interlayer groups, surface group operations, and a flexible layer spacing that makes them ideal catalysts. Over 30 different members of the MXenes family have been explored and successfully utilized as catalysts. Particularly, MXenes have achieved success as a photocatalyst for carbon dioxide reduction, nitrogen fixation, hydrogen evolution, and photochemical degradation. The structure of MXenes and the presence of hydrophilic …

Fluid Droplet Spreading And Adhesion Studied With A Microbalance: A Review, Youhua Jiang, Jaroslaw Drelich

Michigan Tech Publications, Part 1

A contact angle observed for a liquid–solid system is not necessarily a unique value, and a few contact angles need to be considered carefully in relation to liquid spreading, adhesion and phase separation. Understanding of the significance of different contact angles has improved in the last few years through direct measurements of interactive forces between droplets/bubbles and solids together with the simultaneous visualization of the changes in their shapes. A microelectronic balance system is employed to measure the force of spreading after either liquid droplet or gas bubble attachment to a substrate surface and the droplet/bubble–substrate adhesion forces after droplet/bubble …

Transition-Metal Ions In Β-Ga2O3 Crystals: Identification Of Ni Acceptors, Timothy D. Gustafson, Nancy C. Giles, Brian C. Holloway, J. Jesenovec, B. L. Dutton, M. D. Mccluskey, Larry E. Halliburton

Faculty Publications

Excerpt: Transition-metal ions (Ni, Cu, and Zn) in β-Ga₂O₃ crystals form deep acceptor levels in the lower half of the bandgap. In the present study, we characterize the Ni acceptors in a Czochralski-grown crystal and find that their (0/−) level is approximately 1.40 eV above the maximum of the valence band.

Material Characterization And Comparison Of Sol-Gel Deposited And Rf Magnetron Deposited Lead Zirconate Titanate Thin Films, Katherine Lynne Miles

Mechanical Engineering ETDs

Lead zirconate titanate (PZT) has been a material of interest for sensor, actuator, and transducer applications in microelectromechanical systems (MEMS). This is due to their favorable piezoelectric, pyroelectric and ferroelectric properties. While various methods are available to deposit PZT thin films, radio frequency (RF) magnetron sputtering was selected to provide high quality PZT films with the added capability of batch processing. These sputter deposited PZT films were characterized to determine their internal film stress, Young’s modulus, composition, and structure. After characterization, the sputtered PZT samples were poled using corona poling and direct poling methods. As a means of comparison, commercially …

The Impact Of Contact Geometry On Sea Ice Stress And Fracture At The Scale Of Ice Floes, Michael J. May

Dartmouth College Master’s Theses

Observations of stress and strain at the scale of ice floes are necessary to fill a gap in our understanding of sea ice mechanical behavior. Current climate and ice dynamics models represent ice mechanical properties using stress-strain relationships largely determined at laboratory-scale (<1m) or from regional-scale (10+km) deformation observations. The former scale does not include all mechanisms of deformation operating in the ice pack; the latter aggregates multiple modes of deformation into non-physical fluid analogies. The Sea Ice Dynamics Experiment (SIDEx) was run in Feb-Mar 2021 to fill this gap, observing stress and strain at the scale of sea ice failure processes. Here we present stress sensor observations. Stress gages (N=31) were deployed over a 4.5km² area in the southern Beaufort Sea to observe in-situ stress. These data were analyzed in the context of deformation observations from satellite imagery and local laser and radar interferometers to explain the drivers of sea ice stress variations before and after fracture. Three case studies between 14 March and 24 March, during which fractures propagated through …

Sustainable Material For Urea Delivery Based On Chitosan Cross-Linked By Glutaraldehyde Saturated Toluene: Characterization And Determination Of The Release Rate Mathematical Model, Jayanudin Jayanudin, Retno S. D. Lestari, Indar Kustiningsih, Dandi Irawanto, Rozak Rozak, Reyonaldo L. A. Wardana, Fakhri Muhammad

Karbala International Journal of Modern Science

The aims of this study were to characterize the urea-loaded chitosan microspheres and determine the release kinetic constants and diffusion coefficients. An emulsion cross-linking method was used to prepare the urea-loaded chitosan microspheres. Urea was dissolved in a solution of chitosan then put into vegetable oil and stirred to form an emulsion. Glutaraldehyde saturated toluene (GST) was added into the emulsion dropwise while continuously stirring for the solidification process. Chitosan microspheres filled with urea were washed, dried, and then analyzed. Characterization of the urea-loaded chitosan microspheres was conducted using a scanning electron microscope (SEM), Raman spectroscopy, X-ray diffraction, and particle …

Low-Pressure Plasma Surface Treatment Of Polycarbonate And Polyacrylic Plates With Different Plasmas And Their Characterization, Suleyman Gorkem Gizer

USF Tampa Graduate Theses and Dissertations

In this thesis, polycarbonate (PC) and acrylic (PMMA) surfaces were treated with carbon tetrafluoride (CF4), oxygen (O2), and air plasmas with a low-pressure plasma method in order to change their surface properties such as surface free energy and wettability. Moreover, different pattern sized, line, triangular and square shaped surface patterns were used to determine the shape and size-dependent changes. The characteristics of untreated and plasma treated surfaces were examined via contact angle (CA) measurements with distilled (DI) water, against plasma treatment number. Moreover, surface free energy (SFE) calculations of the PC and PMMA surfaces were carried out from sessile drop …

Plasma Treatment Of Polyethylene And Polydimethylsiloxane By Air, Oxygen, And Carbon Tetrafluoride And Their Characterization, Osman Polat

USF Tampa Graduate Theses and Dissertations

In this thesis, low density polyethylene (LDPE) and polydimethylsiloxane (silicone/PDMS) were treated with oxygen (O2) , air and carbon tetrafluoride (CF4) low pressure 13.56 MHz radiofrequency plasma. An experimental setup was used to determine process power and irradiation time for improved modification, the validation was done by measuring the contact angle of the treated samples immediately after treatment. The modification used commercially available sheets to imitate its use in the industry and various applications. The treatment aims to increase/decrease the surface free energy, making it possible to modify the intrinsic inert materials without affecting the bulk. Increased wettability, adhesion, and …

Development Of An Automated Platform For Sensing And Differentiating Vapor-Phase Btex Constituents, Jonathan Samuelson

USF Tampa Graduate Theses and Dissertations

Light aromatic hydrocarbons are an inevitable byproduct of fossil fuel extraction, refinement, distribution, and use. The four lightest and most prevalent of these are benzene, toluene, ethylbenzene, and xylene, which are known collectively as BTEX. In spite of their chemical similarity these species have markedly different effects on human health and substantially different concentrations are permitted by OSHA in workplaces and by the EPA in ambient air and groundwater. Real-time detection, identification, and quantification of these species is therefore of great importance wherever they see industrial use.This work represents the continuation and advancement of a line of research in which …

A Machine Learning Approach To Robotic Additive Manufacturing Of Uv-Curable Polymers Using Direct Ink Writing, Luis A. Velazquez

LSU Master's Theses

This thesis presents the design and implementation of a robotic additive manufacturing system that uses ultraviolet (UV)-curable thermoset polymers. Its design considers future applications involving free-standing 3D printing by means of partial UV curing and the fabrication of samples that are reinforced with fillers or fibers to manufacture complex-shape objects.

The proposed setup integrates a custom-built extruder with a UR5e collaborative manipulator. The capabilities of the system were demonstrated using Anycubic resin formulations containing fumed silica (FS) at varying weight fractions from 2.8 to 8 wt%. To fully cure the specimens after fabrication, a UV chamber was used. Then, measurements …

Sodium Alginate, Nanoclay And Curcumin Based Food Packaging Material For Intelligent Food Packaging Applications, Kalpani Y. Perera, Máille Hopkins, Shubham Sharma, Brendan Duffy, Amit K. Jaiswal, Swarna Jaiswal

Articles

Bionanocomposite food packaging contains materials of biological origin which display high-performance activity when compared to biopolymers and are eco-friendly alternatives to conventional packaging materials. Intelligent packaging monitors the condition of the food or environment surrounding the food and communicates changes to the consumer. This study aimed to develop a bionanocomposite intelligent packaging material by utilising sodium alginate, nanoclay and curcumin. Sodium alginate (2 W/V% SA) film incorporated with 0.3 W/V% curcumin (Cur), glycerol, and nanoclay (NC) in various concentrations (0, 0.5, 1 and 2 W/V %) was prepared using the solvent casting method. The influences of nanoclay and curcumin on …

Biodegradable Active Bio-Nanocomposite Film For The Enhanced Shelf Life Of Tomatoes, Kalpani Y. Perera, Shubham Sharma, Brendan Duffy, Amit K. Jaiswal, Swarna Jaiswal

Articles

The increased environmental pollution has led to finding sustainable solutions for non-renewable plastic-based food packaging materials. Thus, the use of biomaterial-based packaging material has become an immense trend. This work aims at developing an antimicrobial biodegradable chitosanalginate bio-nano composite film with TiO2 nanoparticle (NPs) for food packaging applications. The film was developed by a solution casting method. The chemical, mechanical, thermal, barrier, antimicrobial, and biodegradable properties of the packaging films were evaluated. Packaging studies were performed for 15 days for cherry tomatoes. The designed packaging material had enhanced the mechanical properties with a significantly (p < 0.05) higher tensile strength of 15.76 folds and 2 fold higher elongation at break. The UV barrier properties increased by 88.6%, while the film transparency decreased by 87.23%. Molecular interaction of N-H covalent bonds was observed between alginate and chitosan together with TiO2 NPs. The developed bio-nano composite film showed antimicrobial activity against foodborne pathogens E. coli, S. aureus, S. typhi, and L. monocytogene with a log reduction of 7.08, 7.28, 6.04 & 6.02 log CFU/ml respectively at 24 hours incubation period. The film was completely biodegraded and a weight loss of 89.06% was observed in bio-nanocomposite film during the 3 months. Shelf-life estimation of cherry tomato using developed packaging films showed an increase in the shelf-life up to 8 days with stable pH, total soluble solids, and weight with no bacterial growth when packaged with prepared film. Owing to their improved mechanical, UV barrier, antibacterial, and biodegradability, the prepared active bio-nano composite packaging films could be considered a potential candidate for fruit packaging.

Adiabatic Shear Banding In Nickel And Nickel-Based Superalloys: A Review, Russell A. Rowe, Paul G. Allison, Anthony N. Palazotto, Keivan Davami

Faculty Publications

This review paper discusses the formation and propagation of adiabatic shear bands in nickel-based superalloys. The formation of adiabatic shear bands (ASBs) is a unique dynamic phenomenon that typically precedes catastrophic, unpredicted failure in many metals under impact or ballistic loading. ASBs are thin regions that undergo substantial plastic shear strain and material softening due to the thermo-mechanical instability induced by the competitive work hardening and thermal softening processes. Dynamic recrystallization of the material’s microstructure in the shear region can occur and encourages shear localization and the formation of ASBs. Phase transformations are also often seen in ASBs of ferrous …

Experimental Evidence That Shear Bands In Metallic Glasses Nucleate Like Cracks, Alan A. Long, Wendelin Wright, Xiaojun Gu, Anna Thackray, Mayisha Nakib, Jonathan T. Uhl, Karin A. Dahmen

Faculty Journal Articles

Highly time-resolved mechanical measurements, modeling, and simulations show that large shear bands in bulk metallic glasses nucleate in a manner similar to cracks. When small slips reach a nucleation size, the dynamics changes and the shear band rapidly grows to span the entire sample. Smaller nucleation sizes imply lower ductility. Ductility can be increased by increasing the nucleation size relative to the maximum (“cutoff”) shear band size at the upper edge of the power law scaling range of their size distribution. This can be achieved in three ways: (1) by increasing the nucleation size beyond this cutoff size of the …

Sculpting Charge In Graphene Through Patterned Strain, Dylan J. Balter, Jenna Smith

The Journal of Purdue Undergraduate Research

No abstract provided.

Processing Of Plastic Film From Potato Starch: Effect Of Drying Methods, Kourtney Collier, Samantha Goins, Austin Chirgwin, Isabelle Stanfield

The Journal of Purdue Undergraduate Research

Starch-based plastics are biodegradable, compostable compounds made of starch and plasticizers from natural sources. Their fabrication involves the starch-plasticizer reaction at 70–100°C followed by cooling and drying. Th e most common drying method is air drying (natural convection), which is effective but slow. Th e objective of this work is to study the effect of fast drying (forced convection) on the quality of the plastic film. Th is work compares the effects of drying conditions and drying rate on warpage, shrinkage rate, and presence of bubbles. Five drying methods are studied: (1) natural convection with uncovered petri dish, (2) natural …

Synthesis Of A Phosphorus-Based Epoxy Reactive Flame Retardant Analog To Diglycidyl Ether Of Bisphenol A (Dgeba) And Its Behavior As A Matrix In A Carbon Fiber Composite, Mustafa Mukhtar

Chemical and Materials Engineering Faculty Publications

This paper describes the synthesis of a phosphorus-based flame retardant that is a chemical analog of diglycidyl ether of bisphenol A (DGEBA), as well as its incorporation as a matrix into carbon fiber laminates. Carbon fiber composites, if used for structural applications in mass transport vehicles (aircraft, trains), will require some aspects of improved fire performance to be used safely in those applications. The first phase of work involved the development of two separate synthesis routes to produce the flame retardant monomer, referred to as Phosphorus-DGEBA or simply P-DGEBA. The second step was to determine the viability of the compound's …

Optimizing Switching Of Non-Linear Properties With Hyperbolic Metamaterials, James A. Ethridge, John G. Jones, Manuel R. Ferdinandus, Michael J. Havrilla, Michael A. Marciniak

Faculty Publications

Hyperbolic metamaterials have been demonstrated to have special potential in their linear response, but the extent of their non-linear response has not been extensively modeled or measured. In this work, novel non-linear behavior of an ITO/SiO₂ layered hyperbolic metamaterial is modeled and experimentally confirmed, specifically a change in the sign of the non-linear absorption with intensity. This behavior is tunable and can be achieved with a simple one-dimensional layered design. Fabrication was performed with physical vapor deposition, and measurements were conducted using the Z-scan technique. Potential applications include tunable optical switches, optical limiters, and tunable components of laser sources.

Comparing Structure-Property Evolution For Pm-Hip And Forged Alloy 625 Irradiated With Neutrons To 1 Dpa, Caleb Clement, Sowmya Panuganti, Patrick H. Warren, Yangyang Zhao, Yu Lu, Katelyn Wheeler, David Frazer, Donna P. Guillen, David W. Gandy, Janelle P. Wharry

Materials Science and Engineering Faculty Publications and Presentations

The nuclear power industry has growing interest in qualifying powder metallurgy with hot isostatic pressing (PM-HIP) to replace traditional alloy fabrication methods for reactor structural components. But there is little known about the response of PM-HIP alloys to reactor conditions. This study directly compares the response of PM-HIP to forged Ni-base Alloy 625 under neutron irradiation doses ∼0.5–1 displacements per atom (dpa) at temperatures ranging ∼321–385 °C. Post-irradiation examination involves microstructure characterization, ASTM E8 uniaxial tensile testing, and fractography. Up through 1 dpa, PM-HIP Alloy 625 appears more resistant to irradiation-induced cavity nucleation than its forged counterpart, and consequently experiences …

Fabrication Of Thin-Film Composite, Reverse-Osmosis Membranes With Polyethylenimine Modifications For Enhancing Membrane Fouling Resistance, Stephanie N. Hamilton

Master's Theses

Increasing water reuse opportunities for communities has become increasingly important as access to clean water is becoming more scarce. Reverse Osmosis (RO) is an advanced treatment technology used in water recycling wastewater for potable reuse applications. RO is a promising technology; however, the membranes have limitations including their high energy demand and their susceptibility to membrane fouling. The main objective of this study was to develop a reproducible method for the fabrication of RO membranes with enhanced flux and reduced susceptibility to fouling. Literature contains numerous publications on fabrication of thin film composite (TFC) RO membranes with high performance. However, …

Magnetism In Doped And Hybrid Two – Dimensional Transition Metal Dichalcogenides, Nalaka Kapuruge

USF Tampa Graduate Theses and Dissertations

In recent years, spintronics has gained increasing interest due to the possibility of storing and processing information through the manipulation of both the charge and spin of an electron. Dilute magnetic semiconductors are ideal for the fabrication of such devices as they display carrier-mediated ferromagnetism which allows the electronic control of magnetism. Transferring these properties into the two-dimensional (2D) realm is very attractive for both fundamental research and novel applications. The recent discovery of long-range magnetic order in 2D materials has attracted a growing effort in the search for new functional 2D materials that can display ferromagnetic properties at room-temperature. …

Electrochemical Syntheses Of Nanomaterials And Small Molecules For Electrolytic Hydrogen Production, Jia-Qi Wei, Xiao-Dong Chen, Shu-Zhou Li

Journal of Electrochemistry

Hydrogen is a clean, efficient, renewable energy resource and the most promising alternative to fossil fuels for future carbon-neutral energy supply. Therefore, sustainable hydrogen production is highly attractive and urgently demanded, especially via water electrolysis that has clean, abundant precursors and zero emission. However, current water electrolysis is hindered by the sluggish kinetics and low cost/energy efficiency of both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In this regard, electrochemical synthesis offers prospects to raise the efficiency and benefit of water electrolysis by fabricating advanced electrocatalysts and providing more efficient/value-adding co-electrolysis alternatives. It is an eco-friendly and facile …

Alkaline Seawater Electrolysis At Industrial Level:Recent Progress And Perspective, Tao Zhang, Yi-Pu Liu, Qi-Tong Ye, Hong-Jin Fan

Journal of Electrochemistry

Industrial hydrogen generation through water splitting, powered by renewable energy such as solar, wind and marine, paves a potential way for energy and environment sustainability. However, state-of-the-art electrolysis using high purity water as hydrogen source at an industrial level would bring about crisis of freshwater resource. Seawater splitting provides a practical path to solve potable water shortage, but still faces great challenges for large-scale industrial operation. Here we summarize recent developments in seawater splitting, covering general mechanisms, design criteria for electrodes, and industrial electrolyzer for direct seawater splitting. Multi-objective optimization methods to address the key challenges of active sites, reaction …

A Self-Supported Ru-Cu3P Catalyst Toward Alkaline Hydrogen Evolution, Zi-Xuan Wan, Chao-Hui Wang, Xiong-Wu Kang

Journal of Electrochemistry

Transition metal phosphide (TMP) is a kind of effective catalysts toward hydrogen evolution reaction (HER) in alkaline electrolytes. However, the performance of TMP catalysts is strongly limited by water splitting. In this work, we developed a method to prepare a copper foam (CF) supported Ru-doped Cu₃P catalyst (Ru-Cu₃P/CF) by a consecutive growth of Cu(OH)₂ nanoarrays, soaking in RuCl₃ solution and phosphorization. A large surface area was obtained by the self-supported catalysts with the appropriative Ru doping. As an excellent HER catalyst, it exhibited a low overpotential of 95.6 mV at a current density of …

Catalytic Effect Of Disordered Ru-O Configurations For Electrochemical Hydrogen Evolution, Xue Sun, Ya-Jie Song, Ren-Long Li, Jia-Jun Wang

Journal of Electrochemistry

Phase engineering is considered as an effective method for modulating the electronic structure and catalytic activity of catalysts. The disordered conformation of amorphous materials allows flexible reforming of the surface electronic structure, showing their attractiveness as catalysts for hydrogen evolution reaction (HER). Herein, we designed and developed an amorphous ruthenium dioxide (a-RuO₂) catalyst with a disordered Ru-O configuration. The conformational relationship between Ru-O ordering and HER performance is established by combining advanced electron microscopic techniques with detailed electrochemical tests. Specifically, the disordered Ru-O coordination significantly enhanced the HER catalytic activity in both acidic and alkaline media, ultimately leading …

Alkaline Water Electrolysis For Efficient Hydrogen Production, Wen-Fu Xie, Ming-Fei Shao

Journal of Electrochemistry

Hydrogen production from water electrolysis is a sustainable and environmentally benign strategy in comparison with fossil fuel-based hydrogen. However, this promising technique suffers from the high energy consumption and unsatisfactory cost due to the sluggish kinetics of both half reaction and inferior stability of electrocatalysts. To address this challenge, herein, we present a timely and comprehensive review on advances in alkaline water electrolysis that is already commercialized for large scale hydrogen production. The design principles and strategies with aiming to promote the performance of hydrogen generation are discussed from the view of electrocatalyst, electrode, reaction and system. The challenges and …

Perturbative Theoretical Model Of Electronic Transient Circular Dichroism Spectroscopy Of Molecular Aggregates, Paul C. Arpin, Daniel B. Turner

Materials Science and Engineering Faculty Publications and Presentations

A chiral analog of transient absorption spectroscopy, transient circular dichroism (TCD) spectroscopy is an emerging time-resolved method. Both spectroscopic methods can probe the electronic transitions of a sample, and TCD is additionally sensitive to the dynamic aspects of chirality, such as those induced by molecular excitons. Here, we develop a theoretical description of TCD for electronic multi-level models in which the pump pulse is linearly polarized and probe pulse is alternately left- and right-circularly polarized. We derive effective response functions analogous to those often used to describe other four-wave mixing methods and then simulate and analyze TCD spectra for three …

Feasibility Assessment Of Warm Mix Asphalt In Arkansas, Mohammad Najmush Sakib Oyan

Student Theses and Dissertations

The future of Warm Mix Asphalt (WMA) technologies is promising in the U.S. However, the Arkansas Department of Transportation (ARDOT) does not have any specific guidelines to implement them in the field. This research aims to provide necessary baseline data for WMA as a proof of concept. In this study, three ARDOT approved Performance Grade (PG) binders namely PG 64-22, PG 70-22, and PG 76-22 were investigated. Each of these binders was obtained from two different sources. They were modified by varying doses of four selected additives: Sasobit®, Advera®, Evotherm®, and Rediset®. Additionally, four different types of aggregates (sandstone, limestone, …