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Celik, GokhanSwellable Organically Modified Silica as a Novel Catalyst Scaffold for Catalytic Treatment of Water Contaminated with Trichloroethylene
Doctor of Philosophy, The Ohio State University, 2018, Chemical Engineering
Groundwater contamination by chlorinated compounds is a serious environmental concern because of its potential impact on groundwater and surface water that serves as a major source of public drinking water. Among chlorinated compounds, trichloroethylene (TCE) is one of the most abundantly detected groundwater contaminants with high level of toxicity. The toxicity and the carcinogenic effects of TCE pose a serious threat to human health and the environment. Hydrodechlorination (HDC) is an efficient elimination-based remediation technique to clean groundwater contaminated by chlorinated compounds. In HDC, chlorinated compounds react with hydrogen and are catalytically converted to chloride-free hydrocarbons and hydrogen chloride. Active research on HDC of chlorinated compounds has resulted in promising conversions and catalytic activities over state-of-the-art palladium-based catalysts. However, the existing HDC catalysts reported in the literature suffer from the following shortcomings: (i) catalyst poisoning due to anionic species present in real groundwater such as sulfur-containing species (SO42-, HS-), chloride species (Cl-), etc., (ii) inhibition by the unavoidable reaction product HCl, (iii) formation of carbonaceous species on active sites, and (iv) active metal leaching during operation. The above-mentioned challenges impede the commercialization and widespread utilization of HDC. For industrial organizations to adapt catalytic HDC as a remediation technique, these deactivation issues need to be addressed. Our research has therefore focused on developing a novel catalytic water treatment system in which the deactivation-resistance is improved. The focus of this dissertation is the use of a newly-discovered material, namely swellable organically-modified silicate (SOMS) as a catalyst scaffold for HDC of TCE. SOMS is a highly animated material with unique properties. It is adsorptive, extremely hydrophobic and swellable when contacted with organics. The SOMS structure consists of a cross-linked network of organosilica particles that provide flexibility to the structure of the material. The catalytic system developed in this dissertation has addressed the above-mentioned challenges by utilizing the unique characteristics of SOMS in the following ways: (i) The swelling capability of SOMS allows the active metals dissolved in organic solvents, to be deposited inside the swollen matrix of SOMS. Hence, an effective protection of the active sites is achieved since they are not situated on the exterior surface. (ii) The hydrophobicity of SOMS guides the organics towards the active sites and repels anionic poisons and HCl. Thus, the catalyst deactivation problems are alleviated. (iii) The surface of SOMS does not contain substantial amounts of surface hydroxyls. This was attributed to decreasing the formation of carbonaceous deposits. An experimental approach has been undertaken to demonstrate that the catalytic system developed within this work can meet the above-mentioned challenges. The work performed in this dissertation includes building experimental set-ups where intrinsic kinetic measurements can be performed, developing experimental protocols to synthesize metal-impregnated SOMS, performing aqueous-phase hydrodechlorination activity experiments, performing accelerated-poisoning experiments to investigate the deactivation-resistance characteristics, and carrying out ex-situ and in-situ characterization studies over pristine and poisoned catalysts. These experimental studies were repeated for the commercially-used water treatment catalyst, Pd/Al2O3 in order to have a basis for comparison. In this dissertation, SOMS has been presented as a promising catalyst scaffold due to its unique properties and animated nature. It has the potential to meet the challenges associated with catalytic treatment of water. Based on the studies conducted as a part of this dissertation, it can be concluded that Pd-incorporated SOMS catalysts are catalytically active and more resistant to inhibition and deactivation than the commercially employed counterparts.

Committee:

Umit Ozkan (Advisor); Andre Palmer (Committee Member); Chalmers Jeffrey (Committee Member); Rebecca Kim (Committee Member)

Subjects:

Chemical Engineering

Keywords:

Swellable Organically Modified Silica; SOMS; Hydrodechlorination; Trichloroethylene; Organosilicate; Swelling; Smart Catalytic Materials; Stimuli-Induced Materials; Palladium; Pd-Al2O3; Deactivation; Hydrophobicity; Groundwater remediation

Giammanco, Giuseppe E.Photochemistry of Fe(III)-carboxylates in polysaccharide-based materials with tunable mechanical properties
Doctor of Philosophy (Ph.D.), Bowling Green State University, 2016, Photochemical Sciences
We present the formulation and study of light-responsive materials based on carboxylate-containing polysaccharides. The functional groups in these natural polymers allow for strong interactions with transition metal ions such as Fe(III). The known photochemistry of hydroxycarboxylic acids in natural waters inspired us in exploring the visible light induced photochemistry of the carboxylates in these polysaccharides when coordinated to Fe(III) ions. Described in this dissertation are the design and characterization of the Fe(III)-polysaccharide materials, specifically the mechanistic aspects of the photochemistry and the effects that these reactions have on the structure of the polymer materials. We present a study of the quantitative photochemistry of different polysaccharide systems, where the presence of uronic acids was important for the photoreaction to take place. Alginate (Alg), pectate (Pec), hyaluronic acid (Hya), xanthan gum (Xan), and a polysaccharide extracted from the Noni fruit (NoniPs), were among the natural uronic acid-containing polysaccharide (UCPS) systems we analyzed. Potato starch, lacking of uronate groups, did not present any photochemistry in the presence of Fe(III); however, we were able to induce a photochemical response in this polysaccharide upon chemical manipulation of its functional groups. Important structure-function relationships were drawn from this study. The uronate moiety present in these polysaccharides is then envisioned as a tool to induce response to light in a variety of materials. Following this approach, we report the formulation of materials for controlled drug release, able to encapsulate and release different drug models only upon illumination with visible light. Furthermore, hybrid hydrogels were prepared from UPCS and non-responsive polymers. Different properties of these materials could be tuned by controlling the irradiation time, intensity and location. These hybrid gels were evaluated as scaffolds for tissue engineering showing great promise, as changes in the behavior of the growing cells were observed as a result of the photochemical treatment of the material. We present these natural and readily available, polysaccharide-based, metal-coordination materials as convenient building blocks in the formulation of new stimuli responsive materials. The photochemical methods developed here can be used as convenient tools for creating advanced materials with tailored patterns and gradients of mechanical properties.

Committee:

Alexis Ostrowski, Ph.D. (Advisor); Michael Geusz, Ph.D. (Committee Member); George Bullerjahn, Ph.D. (Committee Member); R. Marshall Wilson, Ph.D. (Committee Member)

Subjects:

Chemical Engineering; Chemistry; Materials Science; Polymer Chemistry; Polymers

Keywords:

photochemistry; polymers; polysaccharides; hydrogels; stimuli-responsive materials; iron; coordination chemistry; biomimetic materials; drug delivery; tissue engineering; cartilage; biomaterials; nanotechnology; photopatterning; green chemistry

Hagerty, PhillipPhysical Vapor Deposition of Materials for Flexible Two Dimensional Electronic Devices
Master of Science (M.S.), University of Dayton, 2016, Chemical Engineering
Molybdenum Disulfide (MoS2) and Tungsten Disulfide (WS2) are two materials in a larger class of materials known as Transition Metal Dichalcogenides (TMDs) that have begun emerge as semiconducting materials. When their horizontal length scale is reduced from bulk to monolayer they demonstrate surprising combinations of properties including a direct electronic band gap and mechanical flexibility. Two dimensional (2D) materials have the potential to revolutionize performance and tailorability of electro-optical devices fabricated entirely from molecularly thin materials. In a departure from traditional exfoliation or high temperature chemical vapor deposition approaches for 2D materials synthesis, novel plasma-based physical vapor (PVD) techniques were used to fabricate uniform films over large areas. This experimental approach allowed unique studies. For example, vapor phase growth allowed systematically variation of the sulfur vacancy concentration in MoS2 and WS2 and subsequent correlation to electronic properties. This effort leads to controlled bottom-up assembly of 2D devices on flexible and standard substrates to experimentally couple the remarkable intrinsic mechanical and electronic properties of ultrathin materials, which are particularly appealing for molecular sensing. The pursuit of an all physical vapor deposited field effect transistor (FET) is the main priority for the 2D materials community as definitive demonstration of the feasibility of physical vapor deposition as a scalable technique for consumer electronics. PVD sputtered Titanium Nitride (TiN) and Tungsten (W) were experimentally characterized as potential back gated materials, Plasma Vapor Deposited (PLD) a-BN was electrically characterized as a uniform ultra-thin low temperature dielectric, and sputtered MoS2 and WS2 were electrically characterized as a semiconductor material. Tungsten deposition methods were previously researched and mimicked for smooth and conductive back gate material depositions. TiN was parameterized and the best room temperature deposition conditions were 70V applied to the sputtering gun with 25 sccm gas flow of 90% N2 and 10% Ar for 60 minutes. The best high temperature depositions were done at 500oC, 70V applied to the sputtering gun with 25 sccm gas flow of 90% N2 and 10% Ar for 30 minutes. Dielectric a-BN electrical characterization began to occur after 6nm which equated to 100 pulses, while 200 pulses equated to 16.5nm thickness. A dielectric constant of 5.90 ± .65 is reported for a-BN for under 20nm thickness. Soft probing techniques by conductively pasted gold wires on the probe tips were required to obtain true electrical measurements of 2D materials in a stacked structure, otherwise scratching would occur and uniformity would cease to exist in the film. Chemical Vapor Deposition (CVD) and mechanical exfoliation have provided the only working TMD semiconductor 2D materials in MOSFET structure to date with lithographic electrical connections. PVD sputtering as a new synthesis method for crystalline TMD with a stoichiometric ratio is achievable over large areas. Though, reduced area depositions are required for doped Silicon and Silicon Oxide (SiO2) based FET structures to limit the chance of encountering a pinhole. With reduced area and stoichiometric enhancement control, sputtered TMD films exhibit high sensitivity to oxygen and are electrically conductive even when exposed to a field effect. Increasing the grain size of the sputtered materials is the next driving force towards a fully recognizable TMD thin film transistor.

Committee:

Christopher Muratore, PhD (Committee Chair); Terrence Murray, PhD (Committee Member); Kevin Myers, DSc (Committee Member)

Subjects:

Aerospace Engineering; Aerospace Materials; Electrical Engineering; Engineering; Materials Science

Keywords:

PVD; materials; 2D materials; Nanoelectronics; TMDs; 2D Transistors; Molybdenum Disulfide; MoS2; WS2; Tungsten Disulfide

Mohi, Amal A.Performance Evaluation of Pavement Markings on Portland Cement Concrete Bridge Decks
Master of Science, University of Akron, 2009, Civil Engineering

The performance of sixteen different pavement marking materials including waterborne traffic paint, thermoplastic, preformed thermoplastic, epoxy, polyurea, modified urethane, methyl methacrylate, and durable tapes, was evaluated on selected Portland cement concrete bridge decks, connected to mainline asphalt pavement, located in Ashland and Richland counties in ODOT District 3 along interstate I-71. Each material was installed in four locations along the three lanes of the interstate. Yellow was installed on the left edge line and white was installed on the two lane lines and the right edge line. All materials were installed in 150-mil grooves to ensure that all traces of the old thermoplastic have been completely removed eliminating its effect on the newly installed products. The groove depth selected was the same as the transverse tines depth on the bridge decks.

The performance evaluation lasted for slightly over two years. The average daily traffic (ADT) was 42,000 for both directions. Two handheld LTL-X retroreflectometers were used for measuring retroreflectivity and one MiniScan XE Plus colorimeter was used for taking color readings. The evaluation included subjectively rating daytime color, nighttime visibility, and durability in accordance to Supplemental 1047 (dated April 18, 2008).

The performance evaluation results obtained during the periodic evaluations were compared to preselected milestone performance criteria. The service life of each marking material was predicted using different mathematical models that estimated the time required for retroreflectivity to drop to a threshold value of 150 mcd/m2/lux for white markings and 100 mcd/m2/lux for yellow markings. The service life predictions were then used to calculate the life cycle costs of the marking materials in order to determine their cost effectiveness.

Committee:

Ala Abbas (Advisor)

Subjects:

Civil Engineering

Keywords:

Road Marking Materials; Pavement Marking Materials

Chang, Cherng-ChiFinite element analysis of laminated composite free-edge delamination specimens /
Doctor of Philosophy, The Ohio State University, 1987, Graduate School

Committee:

Not Provided (Other)

Subjects:

Engineering

Keywords:

Laminated materials;Composite materials;Finite element method

Alalwiat, Ahlam AdnanMass Spectrometry Methods for the Analysis of Biodegradable Hybrid Materials
Doctor of Philosophy, University of Akron, 2015, Chemistry
This dissertation focuses on the characterization of hybrid materials and surfactant blends by using mass spectrometry (MS), tandem mass spectrometry (MS/MS), liquid chromatography (LC), and ion mobility (IM) spectrometry combined with measurement and simulation of molecular collision cross sections. Chapter II describes the principles and the history of mass spectrometry (MS) and liquid chromatography (LC). Chapter III introduces the materials and instrumentation used to complete this dissertation. In chapter IV, two hybrid materials containing poly(t-butyl acrylate) (PtBA) or poly(acrylic acid) (PAA) blocks attached to a hydrophobic peptide rich in valine and glycine (VG2), as well as the poly(acrylic acid) (PAA) and VG2 peptide precursor materials, are characterized by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), electrospray ionization mass spectrometry (ESI-MS) and ion mobility mass spectrometry (IM-MS). Collision cross-sections and molecular modeling have been used to determine the final architecture of both hybrid materials. Chapter V investigates a different hybrid material, [BMP-2(HA)2], comprised of a dendron with two polyethylene glycol (PEG) branches terminated by a hydroxyapatite binding peptide (HA), and a focal point substituted with a bone morphogenic protein mimicking peptide (BMP-2). MALDI-MS, ESI-MS and IM-MS have been used to characterize the HA and BMP-2 peptides. Collisionally activated dissociation (CAD) and electron transfer dissociation (ETD) have been employed in double stage (i.e. tandem) mass spectrometry (MS/MS) experiments to confirm the sequences of the two peptides HA and BMP-2. The MALDI-MS, ESI-MS and IM-MS methods were also applied to characterize the [BMP-2(HA)2] hybrid material. Collision cross-section measurements and molecular modeling indicated that [BMP-2(HA)2] can attain folded or extended conformation, depending on its degree of protonation (charge state). Chapter VI focuses on the analysis of alkyl polyglycoside (APG) surfactants by MALDI-MS and ESI-MS, MS/MS, and by combining MS and with ion mobility (IM) and/or ultra-performance liquid chromatography (UPLC) separation in LC-IM and LC-IM-MS experiments. Chapter VII summaries this dissertation’s findings.

Committee:

Chrys Wesdemiotis, Dr. (Advisor); Leah Shriver, Dr. (Committee Member); Adam Smith, Dr. (Committee Member); Sailaja Paruchuri, Dr. (Committee Member); Matthew Becker, Dr. (Committee Member)

Subjects:

Analytical Chemistry; Chemistry

Keywords:

Mass Spectrometry; the Analysis of Biodegradable Hybrid Materials; Hybrid Materials

Barney, Ian TimothyFabrication and Testing of Hierarchical Carbon Nanostructures for Multifunctional Applications
Doctor of Philosophy (PhD), Wright State University, 2012, Engineering PhD
Multi-scale hierarchical carbon structures have been developed by growing strongly attached carbon nanotubes (CNT) on high surface area substrates having open, interconnected porosity. This investigation was developed on cellular carbon foams but the process is equally suitable for other geometries including flat, fibers, and other porous substrates (interconnected). It is also adaptable to other substrate materials such as metals, alloys or ceramic compounds. Multiwalled carbon nanotubes are grown using a floating catalyst chemical vapor deposition (CVD) method after pre-coating the substrate with a silica nano-layer. The silica-coated graphitic substrates are seen to grow 280 times more nanotubes per unit area compared to bare graphite. Detailed spectroscopic and microscopic studies indicate that this significant improvement can be attributed to improved adhesion and distribution of the iron catalysts and enhanced catalytic activity from substrate interactions. Failure analysis of the nanotube layer under several types of loading demonstrates strong adhesion between CNT and substrate, with failure occurring in the underlying substrate. Attachment of carbon nanotubes can result in more than two orders of magnitude increase in specific surface area as independently confirmed by modeling the microstructure and direct surface area measurement using Brunauer-Emmett-Teller (BET) technique. These hierarchical materials are tested as encapsulation structures for phase change materials (PCM). The CNT can act as nanofin radiators enhancing energy exchange between the thermally conductive encapsulation and the PCM, hence improving thermal response time. A heat cell was designed to compare the response times of foam encapsulation with and without CNT. Encapsulation with CNT is found to have and significantly faster thermal response. DSC measurements demonstrate that CNT/foam hierarchical encapsulation provides 15% higher storage of latent heat. The improvements in thermal responsiveness and storage capacity from CNT/foam encapsulation provide 150% higher specific power (W/g) while transferring the heat into the paraffin wax when compared to the foam without CNT.

Committee:

Sharmila M. Mukhopadhyay, PhD (Advisor); Raghavan Srinivasan, PhD (Committee Member); H. Daniel Young, PhD (Committee Member); P.Terry Murray, PhD (Committee Member); Ajit K. Roy, PhD (Committee Member)

Subjects:

Materials Science

Keywords:

carbon nanotubes; hierarchical materials; carbon foam; phase change materials; paraffin wax; BET; silica

Grant, Stacy M.Polymer Templating Synthesis, Adsorption and Structural Properties of Alumina-Based Ordered Mesoporous Materials
PHD, Kent State University, 2011, College of Arts and Sciences / Department of Chemistry

The main objective of this research was to develop a more complete understanding of underlying chemical processes taking place in the one-pot modified sol-gel synthesis of ordered mesoporous alumina and alumina-based metal oxides. This was accomplished through exploration of the effects of altering synthesis parameters (polymer template, acid concentration, etc.), substitution of constituents (nickel, titanium, etc.) or by the introduction of additives (co-solvent molecules) on the resulting material’s structural properties. In tandem with this approach was the optimization of these alterations in order to produce well ordered mesoporous alumina and alumina-based metal oxides. A secondary goal was in creating general synthesis strategies for tailoring these materials for use in a number of applications.

This project resulted in an increased understanding of the cooperative self-assembly process and the effects of various synthesis components and conditions. The most influential variable in the synthesis mixture is the polymer template which determines pore morphology. Variations from optimal resulted in small decreases in both surface area and pore volume. The second most influential variable is acid concentration. Acid concentration is directly proportional to pore width, up to a limiting concentration. Higher acid concentration also led to higher thermal stability and evidence of transitions from the hexagonal to the cubic phase. The addition of co-solvent molecules at low temperature affected the resulting pore volumes and induced microporosity. Unlike their siliceous counterparts, ordered mesoporous alumina did not display the clear relationship between co-solvent concentration and mesopore width. Materials were found to be stable and the synthesis was highly reproducible.

A sample preparation method for alumina-based metal oxides was demonstrated. This method was found to be limited by additional metal, it’s suitability for an acidic synthesis and it’s compatibility with the alumina framework. However, it was shown that alumina-based metal oxides (specifically nickel- and titanium-aluminum oxide) result in thermally stable, ordered (up to ~20% additional metal) mesopores with a high degree of thermal stability and crystallinity. Materials were present as a mixed metal phase at the stoichiometric equivalent with excesses of either metal at other equivalents. These materials are currently being used in research labs around the world to determine their suitability for numerous industrial applications.

Committee:

Mietek Jaroniec, Dr. (Committee Chair); Anatoly Khitrin, Dr. (Committee Member); Songping Huang, Dr. (Committee Member); John Portman, Dr. (Committee Member); Deng-Ke Yang, Dr. (Committee Member)

Subjects:

Chemistry; Materials Science

Keywords:

ordered mesoporous materials; polymer templated; alumina; aluminum oxide; alumina-based oxides; mesoporous oxides; high surface area catalytic materials

Billy, Joshua ThomasInvestigating the Electrochemical Conversion of Carbon Dioxide to Fuels
Doctor of Philosophy, The Ohio State University, 2018, Chemistry
The upsurge in anthropogenic activities since the Industrial Revolution has led to an increase in atmospheric carbon dioxide (CO2) concentration that is a significant factor in global climate change. Attempts to curtail a further rise in atmospheric CO2 concentration include technology that captures and sequesters CO2 from local point sources where it is being emitted and/or capture and conversion technologies that transforms CO2 to other chemicals that can be used as raw materials, such that no additional consumption of fossil fuels is need to create these raw materials. Currently, there are no large commercial processes that convert CO2 to useful chemicals, save for the water-gas shift that leads to the Fischer-Tropsch process, but both of these reactions require a large amount of energy input. Simpler methods exist, such as the electrochemical conversion of CO2, which can be performed in aqueous solution at room temperature and atmospheric pressure. This CO2 utilization pathway, however, is not yet fully developed for several reasons: lack of a selective and robust catalyst, large energy input required for desirable products, and low rate of reaction. The electrochemical CO2 reduction reaction (CO2RR) has been widely studied in recent years but is still in its infancy. This work addresses various challenges faced in the design of selective and active catalyst materials while also focusing on experimental design and providing insights into the CO2RR mechanism. Due to copper’s (Cu) unique ability to convert CO2 to hydrocarbons and alcohols, Cu-based materials are of prime interest. Planar Cu foils served as a model catalyst for experimental parameter studies in this work, in which we found that gas and solution flow rates, as well as electrochemical cell design, play a crucial role in controlling the selectivity of the reaction. Cu foils were also used as a model in isotopic labelling experiments that provide insights into the CO¬2RR mechanism, such that bicarbonate (HCO3-) was determined to be the primary proton donor in the reduction of CO2 to hydrocarbons and alcohols. Unique nanostructured Cu materials were synthesized in the lab through etching of a Cu-Al alloy, creating a porous Cu of nano-size, herein described as nanoporous Cu. Increased CO2RR activity and unique selectivity was observed on nanoporous copper and could be further enhanced by making bimetallic variations of the material. Similar results were also obtained using Cu nanoparticles purchased elsewhere.

Committee:

Co Anne (Advisor); Olesik Susan (Committee Member); Wu Yiying (Committee Member); Lal Rattan (Committee Member)

Subjects:

Chemistry; Energy; Materials Science

Keywords:

electrochemistry; chemistry; carbon dioxide; CO2; electrocatalysis; materials; copper; CO2 conversion; catalytic materials; catalysis

Myers, JoshuaNANO-MATERIALS FOR MICROWAVE AND TERAHERTZ APPLICATIONS
Doctor of Philosophy (PhD), Wright State University, 2015, Engineering PhD
In this age of digital electronics the quest for faster computational devices and high speed communications have driven a need for new materials that are capable of fulfilling these goals. In both areas the need for a thinner channel in transistors, faster carrier transport characteristics, and better magnetic materials dominate the direction of research. Recently 2D materials have been realized. These single layer atomic thick materials show potential in having extremely high carrier transport velocities at room temperature and, due to their natural 2D structure, are the thinnest material possible in nature. On the other hand spin-spray ferrites have showed potential in producing high permeability, low loss materials with a low processing temperature compatible with current CMOS technology. One of the largest hindrances in the implementation of these materials are the lack of measurement capabilities. Both 2D materials and spin-spray ferrites have nm sized features that significantly change how the material behave. To further investigate these materials scanning microwave microscopy (SMM) is being developed as a possible characterization tool. SMM has the unique ability to collect the complex reflection coefficient simultaneously with the topography at nm horizontal spatial resolutions. The complex reflection coefficient is able to supply valuable information about materials such as conductivity and permittivity. This dissertation provides an in depth look at the potential applications for SMM and supplies a rigorous characterization, both experimentally and numerical simulations, of the SMM system. In detail we re- port first time SMM measurements of graphene's conductivity and permittivity along with characterization of graphene defects induced by oxygen plasma etching and graphene wrinkles. We have also experimentally show conductive grain boundaries in spin-spray ferrites leading to larger than expected losses. Lastly we show Fourier transform inferred spectroscopy measurements of graphene micro and nano ribbons. These results show the versatility of SMM and the ability to further characterize new materials. Furthermore we show the ability of the SMM to obtain calibrated conductivity and permittivity measurements on the nanoscale level leading to a more complete understanding of the effects of defects on the electrical properties of graphene and understanding of the losses in ferrimagnetic materials.

Committee:

Yan Zhuang, Ph.D. (Advisor); Marian Kazimierczuk, Ph.D. (Committee Member); Douglas Petkie, Ph.D. (Committee Member); LaVern Starman, Ph.D. (Committee Member); Shin Mou, Ph.D. (Committee Member)

Subjects:

Atoms and Subatomic Particles; Electrical Engineering; Electromagnetics; Engineering; Materials Science; Nanoscience; Nanotechnology; Optics

Keywords:

Scanning Microwave Microscope; Graphene; 2D Materials; AFM; Plasmonics; THz; Photonics; Defects; Nano-Materials, Spin-Spray, Ferrite

Xu, MubingAdaptive-passive and active control of vibration and wave propagation in cylindrical shells using smart materials
Doctor of Philosophy, University of Akron, 2005, Engineering
Smart materials are increasingly used in structural control of vibration and wave propagation. Most of existing studies have focused on the vibration control using smart materials in the form of patches or films, and ring-type has seldom been used. There is not much research on control of cylindrical shells using tunable materials. To meet this need, the present study develops theoretical models for adaptively–passive and active control of vibration and wave propagation in cylindrical shells using smart materials. One unique characteristic of shape memory alloy (SMA), i.e., the controllable elastic modulus with respect to temperature, is adopted in adaptively–passive control of vibration; with the capability of providing line circumferential distributed control forces due to their property of piezoelectricity in piezoelectric ceramic materials (e.g., PZT), the ring-type actuators are proposed to actively control the forced vibration response. The cylindrical shells both in vacuo and filled with fluid are investigated, and two different problems are considered: one is the wave propagation and transmission, and the other is the forced vibration response from external excitation. With the controllable elastic modulus of SMA, SMA wall joint has the capability of controlling the vibration source with wide-band frequencies or with a time-varying frequency. With the solution of the characteristics of the free wave propagation from the dispersive equation, the vibration response and characteristics of reflection/transmission from incident wave are investigated by using the wave approach and the method of residues. Numerical simulation indicates that the SMA wall joint has the potential to solve the problem of pass-band, and the transmission loss is more than 20dB for all frequency ranges providing a proper temperature. This SMA wall joint is also adopted to adaptively control the forced vibration response from external excitation. Parametric study demonstrates that the SMA joint has the capability of controlling the forced vibration of the shell excited by external excitation, and increasing damping ratio in the SMA joint does not mean to improve its vibration control performance. With the property of piezoelectricity, the piezoelectric ceramic material is able to function as both sensors and actuators. With the capability to offer more control authority by providing active control line force/moment, the ring-type PZT actuator (being modeled as a line circumferential distributed control force) is adopted to actively control the vibration in cylindrical shell. The transmission loss of this active control method is obtained by using the theory of residues. Simulation results demonstrate that it is possible to achieve a vibration reduction of 20 dB for the shells both in vacuo and filled with fluid by using only one control force. In summary, the present study illustrates the effectiveness and capabilities of smart materials (e.g., SMA and PZT) on control of vibration and wave propagation in cylindrical shells, and the proposed theoretical models provide better understanding of vibration and wave propagation behaviors of cylindrical shells with smart materials and can be used to guide design and analysis of smart cylindrical shell structures.

Committee:

Pizhong Qiao (Advisor)

Subjects:

Engineering, Mechanical

Keywords:

vibration and wave propagation control; smart materials; adaptively&8211;passive control; active control; shape memory alloy; piezoelectric ceramic materials(PZT); fluid-shell coupled system

Fletcher, Aaron ThomasA Study of Alkali-Resistant Materials for Use in Atomic Physics Based Systems
Master of Science (MS), Wright State University, 2017, Physics
Due to shortcomings in emerging alkali-based atomic physics based systems, a need to investigate alkali resistant materials has arisen. There is interest in alkali based systems such as atomic clocks and diode pumped alkali laser (DPAL) systems. In the case of atomic clocks and DPALs, alkali metal vapor, such as Rb, is the active part of the systems. The alkali vapor is confined in some manner of housing, but the transmission of electromagnetic radiation is required in the cells. This requires the incorporation of windows into the cell. The current window material, however, have been shown to degrade over time, thus reducing the effectiveness of these systems. It is believed that the alkali atoms diffuse into the bulk of the housing material. This diffusion results in changes of optical and, in some cases, structural properties of the material. These changes lead to the degradation of window materials in these alkali-based systems. In an effort to improve the longevity of alkali-based systems, a material study was conducted to identify window material that could resist diffusion-based changes in optical properties. Candidate materials were selected based on their structure, optical properties, and/or density. All candidate materials underwent baseline characterization. Baseline characterization techniques included atomic force microscopy, spectrophotometry, reflectometry, ellipsometry, and X-ray diffraction spectroscopy. Once baseline data was collected, the candidate materials were exposed to Rb at high temperatures for an extended period of time to simulate atomic physics devices. Exposure was achieved by heating the Rb source to ~ 550 °C while the candidate materials were kept at ~ 450 °C. This created a 100 °C temperature gradient to thoroughly expose the materials to gaseous Rb. After exposure, the materials underwent the same analysis techniques to ascertain the changes in structural and optical properties. Additionally, time of flight secondary ion mass spectroscopy depth profiling was conducted to quantitatively determine the depth of Rb into the bulk of the material. The results of this research effort found that highly crystalline materials were capable of resisting alkali diffusion better than amorphous materials, often only tens of nm. Their optical properties were also relatively unchanged. Amorphous materials were not able to resist the diffusion of Rb; diffusion depths were shown to be on the order of microns. Based on this research effort, aluminum oxynitride, MgAl2O4, MgO, and ZrO2 are being recommended as materials that will improve the longevity of emerging atomic physics systems. A vapor cell made from ZrO2 was fabricated and is being evaluated for use in atomic clock systems. For DPAL systems, window materials will need to be further tested to determine whether it can resist the high fluence laser radiation after being exposed to Rb.

Committee:

Gregory Kozlowski, Ph.D. (Advisor); Steven Fairchild, Ph.D. (Committee Member); David Turner, Ph.D. (Committee Member)

Subjects:

Materials Science; Physical Chemistry; Physics

Keywords:

ToF-SIMS; DPAL; laser windows; laser optics; alkali diffusion; materials science; optical materials

Cheekati, Sree LakshmiGRAPHENE BASED ANODE MATERIALS FOR LITHIUM-ION BATTERIES
Master of Science in Engineering (MSEgr), Wright State University, 2011, Materials Science and Engineering
Improvements of the anode performances in Li-ions batteries are in demand to satisfy applications in transportation. In comparison with graphitic carbons, transition metal oxides as well as graphene can store over twice amount of lithium per gram. Recently, graphene-based anodes for Li-ion batteries are under extensive development. In this research, lithium storage characteristics in graphene oxide (GO), GO/Manganese acetate (GO/MnAc), GO/manganese oxide (GO/MnOx) composites and Nano Graphene Platelets (NGP) were studied. The prepared GO delivered reversible capacities of 706mAh/g with an average columbic efficiency of 87%. Reversible capacities of 533 mAh/g were observed for GO/MnAc composite. GO/MnOx nanocomposite thermal annealed at 400°C in inert atmosphere exhibited high reversible charge capacity of 798 mAh/g with an average columbic efficiency of 95% and capacity fade per cycle of 1.8%. The EIS spectra of discharge and charge profiles of GO and GO/MnOx composites were analyzed to investigate the kinetics evolution of electrode process at different stages of lithium storage.

Committee:

Hong Huang, PhD (Advisor); Daniel Young, PhD (Committee Member); Chu Kuan-lun, PhD (Committee Member); George Huang, PhD (Other)

Subjects:

Alternative Energy; Automotive Materials; Chemistry; Energy; Engineering; Materials Science; Metallurgy; Nanotechnology

Keywords:

Lithium Ion Batteries; Anode Materials; Graphene; Graphene Oxide; Nano Graphene Platelets; Graphene Oxide Manganese Acetate Composite; Graphene Oxide Manganese Oxide Nano Composite; Electrochemical Impedance Spectroscopy; Graphene Based Anode Materials;

Abedsoltan, HosseinMeso-Scale Wetting of Paper Towels
Master of Science, Miami University, 2017, Chemical, Paper & Biomedical Engineering
In this study, a new experimental approach is proposed to investigate the absorption properties of some selected retail paper towels. The samples were selected from two important manufacturing processes, conventional wet pressing (CWP) considered value products, and through air drying (TAD) considered as high or premium products. The tested liquids were water, decane, dodecane, and tetradecane with the total volumes in micro-liter range. The method involves the point source injection of liquid with different volumetric flowrates, in the nano-liter per second range. The local site for injection was chosen arbitrarily on the sample surface. The absorption process was monitored and recorded as the liquid advances, with two distinct imaging system methods, infrared imaging and optical imaging. The microscopic images were analyzed to calculate the wetted regions during the absorption test, and the absorption diagrams were generated. These absorption diagrams were dissected to illustrate the absorption phenomenon, and the absorption properties of the samples. The local (regional) absorption rates were computed for Mardi Gras and Bounty Basic as the representative samples for CWP and TAD, respectively in order to be compared with the absorption capacity property of these two samples. Then, the absorption capacity property was chosen as an index factor to compare the absorption properties of all the tested paper towels.

Committee:

Steven Keller (Advisor); Shashi Lalvani (Committee Member); Douglas Coffin (Committee Member)

Subjects:

Chemical Engineering; Forestry; Materials Science; Mechanical Engineering

Keywords:

Porous Materials; Low-density Materials; Paper Science; Liquid flow; Wetting; Absorption; Absorption Models and Methods; Paper towel absorption properties; Image processing and analysis

Barrera Martinez, Cindy SofiaNovel Renewable Materials from Natural Rubber and Agro-Industrial Residues
Doctor of Philosophy, The Ohio State University, 2016, Food, Agricultural and Biological Engineering
Natural rubber is currently one of the most important crop-produced industrial bio-based materials in the world. Further improvements in rubber inherent properties are obtained by the addition of fillers, enabling polymeric products suited to highly demanding applications. However, most existing fillers are neither renewable nor sustainable. Agro-industrial residues are highly abundant solid wastes that represent a promising source of alternative fillers. Moreover, the renewable character of these residues could improve the sustainability of natural rubber products while adding value to these waste materials. Fillers obtained from agro-industrial residues, namely, eggshells, carbon fly ash, processing tomato peels and guayule bagasse, were used for the manufacture of composites with both hevea and guayule natural rubber. The effect of amount, type and particle size of waste-derived fillers on power consumption during mixing of the rubber compounds, and on mechanical properties of compression molded test pieces were investigated. Waste-derived fillers were used as partial and complete replacement of petroleum-derived carbon black (industrial reference reinforcing filler). Unfilled compounded rubber and composites containing carbon black with no other filler were used as reference materials. Reinforcement of unfilled hevea and guayule rubber compounds was obtained with most waste-derived fillers used, particularly composites containing micro and nano sized eggshells and tomato peel particles. This can be attributed to different factors related to filler characteristics including particle structure, size, bulk density, alkalinity and surface activity. The introduction of co-filler systems, in this case carbon black with various waste-derived materials at low loadings, generated materials with superior or similar mechanical properties than those of composites made solely with carbon black. This reinforcement may reflect a combined synergistic reinforcing effect of carbon black particles, which possess a strong polymer-filler interaction, with the formation of a unique network between the rubber and the waste-derived materials. This effect was more pronounced in guayule than hevea rubber as a result of differences in rubber structure and composition (non-rubber components) between these two natural rubber matrixes. These differences affect the overall reinforcement achieved with the waste-derived fillers. These results could strengthen ongoing commercialization efforts of guayule products. Unusual combinations of mechanical properties were achieved with both types of rubber. Also, this work showed that micro sized fillers are effective reinforcing fillers. Micro-fillers can be produced at a far lower cost than their nano-sized versions.

Committee:

Katrina Cornish, PhD (Advisor); Kurt Koelling, PhD (Committee Member); Ajay Shah, PhD (Committee Member); Alfred Soboyejo, PhD (Committee Member)

Subjects:

Engineering; Polymers

Keywords:

Renewable Materials from Natural Rubber, Renewable Materials from Agro-Industrial Residues

Margowati, MargarethaLaboratory characterization of Ohio-strategic highway research program test road pavement materials
Master of Science (MS), Ohio University, 2001, Civil Engineering (Engineering)
Laboratory characterization of Ohio-strategic highway research program test road pavement materials

Committee:

Teruhisa Masada (Advisor)

Subjects:

Engineering, Civil

Keywords:

Laboratory Characterization; Ohio-Strategic Highway; Test Road Materials; Pavement Materials

Littell, JustinThe Experimental and Analytical Characterization of the Macromechanical Response for Triaxial Braided Composite Materials
Doctor of Philosophy, University of Akron, 2008, Civil Engineering

Increasingly, carbon composite structures are being used in aerospace applications. Due to their high strength, high stiffness and low weight properties, they are good candidates for replacing many aerospace structures currently made out of aluminum or steel. Recently, many of the aircraft engine manufacturers have been developing new commercial jet engines which will use composite fan cases. Instead of using traditional composite layup techniques, these new fan cases will use a triaxially braided pattern, which improves case performance. The impact characteristics of composite materials for jet engine fan cases applications have been an important research topic, because federal regulations require that an engine case must be able to contain a blade and blade fragments during an engine blade out event. Once the impact characteristics of these triaxial braided materials are known, computer models can be developed to simulate a jet engine blade out event, thus reducing cost and time for development of these composite jet engine cases. The two main problems that have arisen in this area of research are that the material properties for these materials have not been fully determined, and computationally efficient computer models, which incorporate much of the micro-scale deformation and failure mechanisms, are not available.

This research addressed some of the deficiencies present in previous research regarding these triaxial braided composite materials. This research developed new techniques to accurately quantify the material properties of the triaxial braided composite materials. New test methods were developed for the composite constituent, the polymer resin, and representative composite coupons. These methods expanded previous research by using novel specimen designs along with using a non-contact measuring system which was also capable of identifying and quantifying many of the micro-scale failure mechanisms present in the materials. Finally, using the data gathered, a new hybrid micro-macromechanical computer model was created to simulate the behavior of these composite material systems under static and ballistic impact loading using the test data acquired. It also quantified how the fiber/matrix interface affected material response under static and impact loading.

The results showed that the test methods were capable of accurately quantifying the polymer resin under a variety of strain rates and temperature for three loading conditions, which is a constituent in the composite material. The resin strength and stiffness data showed a clear strain rate and temperature dependence. The data also showed the hydrostatic stress effects and hysteresis, all of which can be used by researchers developing composite constitutive models for the resins. The results for the composite data showed noticeable differences in strength, failure strain and stiffness in the different material systems presented. The investigations into the micro-scale failure mechanisms provided insights into the nature of the different material systems behaviors. Finally, the developed computer model predicted composite static strength and stiffness to within 10% of the gathered test data. It also agreed with the composite impact data, where available.

Committee:

Wieslaw Binienda, PhD (Advisor)

Subjects:

Aerospace Materials; Civil Engineering; Engineering; Mechanical Engineering; Mechanics; Polymers

Keywords:

Composite Materials; Materials Testing; Optical Measurement; Photogrammetry; Computer Modelling; Impact Simulation

Ko, Ying-hsiangThe growth of metal particles in porous glass and the dielectric and optical properties of the composites /
Doctor of Philosophy, The Ohio State University, 1986, Graduate School

Committee:

Not Provided (Other)

Subjects:

Engineering

Keywords:

Composite materials;Composite materials;Glass

James, Sheronica L.Transcranial Ultrasound as a Potential Modality for Real-Time Observation of Brain Motion
Doctor of Engineering, Cleveland State University, 2017, Washkewicz College of Engineering
Brain-related injuries are a major public health concern in the United States, and an estimated 70,000 to 90,000 people per year consequently suffer from significant and/or irreversible disabilities following traumatic brain injury. While the severity of head motion, namely acceleration, can be a good indicator of the cause of injury, a measure of the stresses and strains placed on the brain during trauma has yet to be realized due to an inability to directly observe brain motion and deformation under such conditions in real time. Such measures may be equally important in characterizing brain motion under non-traumatic conditions, such as cerebellar tonsillar ectopia, where it is speculated that motion of the cerebellar tonsils is dramatically increased. The objective of this dissertation was to investigate transcranial ultrasound as a potential modality for direct, real-time observation of brain motion. To test this approach in controlled laboratory experiments a custom ultrasound system was designed and a custom head model comprising an ex-vivo human skull and brain tissue-mimicking phantom matched for acoustic velocity and mechanical stiffness to human brain was developed. The portability, affordability and real-time visualization capability of this model system present a unique tool for investigating brain motion under aberrant conditions and may aid in clinical decision-making.

Committee:

Gregory T. Clement, Ph.D. (Committee Chair); Aaron Fleischman, Ph.D. (Committee Member); Moo Yeal Lee, Ph.D. (Committee Member); Anne Su, Ph.D. (Committee Member); D. Geoffrey Vince, Ph.D. (Committee Member)

Subjects:

Acoustics; Biomechanics; Biomedical Engineering

Keywords:

Transcranial ultrasound; Brain motion; Biomechanics of brain tissue; Tissue-mimicking materials

Lichtensteiger, Michael J.Impact analysis of viscoelastic spheres, fruits and vegetables with rigid, plane surfaces /
Doctor of Philosophy, The Ohio State University, 1982, Graduate School

Committee:

Not Provided (Other)

Subjects:

Engineering

Keywords:

Fruit;Vegetables;Cushioning materials

Moussa, Atef BassiliA coupled problem of finite deformation and flow in porous media /
Doctor of Philosophy, The Ohio State University, 1980, Graduate School

Committee:

Not Provided (Other)

Subjects:

Education

Keywords:

Porous materials;Fluid mechanics

Waitus, Lorin VictorConceptualizing a body of knowledge of solid materials processing with implications for curriculum development /
Doctor of Philosophy, The Ohio State University, 1972, Graduate School

Committee:

Not Provided (Other)

Subjects:

Education

Keywords:

Industrial arts;Materials

Fain, Charles CliffordInfluence of localized matrix recrystallization on the strength of triaxial ceramics /
Doctor of Philosophy, The Ohio State University, 1967, Graduate School

Committee:

Not Provided (Other)

Subjects:

Engineering

Keywords:

Ceramics;Strength of materials

Yoldaş, Bülent ErtürkElectrochemistry of glass-refractory interfaces and refractory corrosion /
Doctor of Philosophy, The Ohio State University, 1966, Graduate School

Committee:

Not Provided (Other)

Subjects:

Engineering

Keywords:

Refractory materials;Electrochemistry

Baich, Liseli JeanetteImpact of Infill Design on Mechanical Strength and Production Cost in Material Extrusion Based Additive Manufacturing
Master of Science in Engineering, Youngstown State University, 2016, Department of Mechanical and Industrial Engineering
The widespread adoption of Additive Manufacturing (AM) can be greatly attributed to the lowering prices of entry-level extrusion-based 3D printers. It has enabled the use of AM for prototypes, STEM education and often, to produce complex custom commercial products. With increased access to material extrusion-based 3D printers and newer materials, the influence of print parameters such as infill patterns on resulting mechanical strength and print costs, need to be investigated. This research investigates the relationship among (1) infill designs, (2) selection of printer (entry-level vs. production grade), (3) mechanical properties (e.g. tensile, compressive and flexural) and (4) production cost (print time and material). Finite Element Analysis (FEA) simulation using ANSYS software was conducted on the 4-point bending specimens to develop an FEA model that was correlated with the experimental data (±8% accuracy). Relevant infill designs are evaluated and recommended based on the loading conditions and savings in production cost when compared to solid infill design. In the case of tension, a larger air gap in the infill design was the most cost effective. In the case of compression, low density and high density infills were more cost effective when compared to solid samples. In the case of the flexural loading, low density infill was also the most cost effective infill design. It was found that print time had a greater effect on total cost and hence, influence of print time is analyzed using both entry-level and production grade printers. The findings from this study will help formulate criteria for selection of optimal infill design based on loading conditions and cost of printing. In summary, it was found that in the case of entry-level printers, solid infill design is preferred due to minimal cost savings when compared to other infill designs. On the contrary, it was found that low density infill is more cost efficient than solid infill design while using production-grade printers.

Committee:

Guha Manogharan, PhD (Advisor); Hazel Marie, PhD (Committee Member); Jae Joong Ryu, PhD (Committee Member)

Subjects:

Industrial Engineering

Keywords:

3D printing; cost analysis; manufacturing; infill pattern; FEA analysis; production cost; materials

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