Master of Science, University of Toledo, 2024, Geology

Traditional soil investigation methods often involve point-source data from laboratory-scale analysis on soil cores or the use of in-situ sensors to directly measure soil physiochemical properties such as soil moisture content. These methods are destructive, costly, time-consuming, and inadequate in capturing details of spatial variation in the soil types and properties. Geophysical methods present non-invasive approaches for estimating the spatial variation in soil properties, but gaps still exist in using fast, non-contact-based geophysical methods such as electromagnetic imaging (EMI) and ground penetrating radar (GPR) for characterizing vertical variation in soil properties. Also, the effect of polarization on interpreting the electrical conductivity, e.g., from EMI of variably saturated soil, remains poorly studied, limiting the use of electrical geophysical methods for characterizing soil properties. This research assesses the use of electrical conductivity from EMI and GPR's radargrams for characterizing the vertical distribution of soil moisture, organic matter, and texture. It used laboratory-based spectral induced polarization (SIP) measurements to assess the electrical polarization of the soil. Co-located EMI and GPR measurements were acquired along 12 transects at the Stranahan Arboretum research sites in Toledo, Ohio. Soil samples were collected from nine locations along the EMI and GPR transects, segmented into 63 subsamples, and analyzed for soil moisture content (SMC), soil organic matter content (SOM), and percentage sand, silt, and clay contents. The apparent electrical conductivity from the EMI survey were also inverted using the EmagPy software to obtain vertical variation of the soil electrical conductivity. 20 minimally disturbed soil cores were later collected for laboratory SIP measurements. A linear regression model was used to assess the relationship between the soil electrical signals and the laboratory-derived soil physiochemical prop (open full item for complete abstract)

Master of Science, University of Toledo, 2022, Geology

Wetlands' water and nutrient retention functions depend on their soil properties, hence the need to understand the spatial-temporal variation of these properties. The use of soil cores and in situ sensors to assess soil properties distribution is limited due to their high cost, field efforts, and disturbances. This study seeks to advance the use of non-invasive geophysical methods using soil electrical conductivity via electromagnetic imaging (EMI) for estimating wetlands' soil properties distribution. First, I acquired spatial distribution of soil apparent electrical conductivity (ECa) and magnetic susceptibility (MSa) via EMI over a 162,000 m2 restored wetland using an EM-38-MK2 instrument towed behind a utility terrain vehicle equipped with a differential ground positioning system. I collected twenty-two undisturbed soil samples and analyzed them in the laboratory for soil moisture (SMC), organic matter (SOM), porosity, bulk density, and texture. A linear regression model was used to compare the correlation between each soil property with measured ECa and MSa, while ECa was used to predict the distribution of SMC and SOM using the statistical model validated using a leave-one-out technique. Measured ECa correlates strongly with soil texture, SMC, and SOM, with SOM showing a slightly dominant control. These results show that ECa can predict the distribution of SMC and SOM in wetland soils to an accuracy of ~67-70% for these datasets. While these results validate the potential for extending EMI to characterize wetland soils, reliance on statistical correlation is limited to the study site and data range. Cross-correlation between the soil properties also limits understanding of the contribution of each soil property to the measured bulk conductivity. Decoupling this requires a mechanistic understanding of the current conduction processes within wetland soils, considering electromigration via the soil pore fluid and surface conduction at the grain-fluid interface. T (open full item for complete abstract)

Doctor of Philosophy (PhD), Ohio University, 2022, Physics and Astronomy (Arts and Sciences)

Amorphous materials have myriad applications. There are persistent challenges in understanding their structure due to the absence of long range order. Ab initio methods are useful tools to model these materials and determine their microscopic properties. To utilize materials for technological applications, understanding of electronic transport is of central importance. More specifically, for a heterogeneous system, determining conduction-active sites in the network may provide an insight to engineer the material for a desired application. In this dissertation, we describe and develop a novel method to project electronic conductivity onto real-space grids and visualize conduction-active sites in selected materials. To implement the method, we utilize the Kohn-Sham eigenvalues and eigenfunctions obtained from hybrid functional calculations. We then apply the method to study conduction mechanisms in insulating, semi-conducting, metallic and mixed systems. In this dissertation, we also describe atomistic modeling of two promising resistive memory materials: amorphous aluminum oxide (a-Al2O3) and silicon suboxide (a-SiOx). For the former case, we study the impact of transition metal Cu in a highly ionic host a-Al2O3 and discuss its effect to electronic structure and transport in the material. We reveal that the Cu atoms segregate and form a cluster or chain-like structure in the oxide host. We find that such Cu-cluster/chain like network forms the major conduction-active sites in the material. For the latter case, we present a-SiOx models with x = 1.7, 1.5 and 1.3 and study their structure and electronic transport. In our study, we find that the decrease in x results in the complexity of the network with different tetrahedral structures of the form SiSiyO4−y where y = 0 to 4. This results in different types of oxygen (O)-vacancy sites in the material. We propose that a-SiOx also has a potential as a computer security device: physical unclonable functions (PUFs) (open full item for complete abstract)

MS, University of Cincinnati, 2019, Engineering and Applied Science: Materials Science

Two limitations of polymeric fiber reinforced composite materials are their susceptibility to damage, and their reduced thermal conductivity compared to metals. This thesis proposes techniques to address these limitations and to make composite materials more multi-functional and reliable like metals. Laminated composites are prone to damage due to impacts which cause localized delamination and microcracking. It is challenging to detect these types of damages because non-destructive inspection takes the structure out of service, inspection is slow and expensive on large structures, and the damage may not be obvious on the outer surface. Left undetected, the damage can propagate due to loading during normal use and lead to reduced performance or failure of a component or the entire structure. In most applications, detection of these internal damages is critical to maintain the performance and structural integrity of components, and to assure the safety of the aircraft or wind turbine. Composites are used because they are lightweight and corrosion resistant, but must be over-designed to account for possible undetected damage which increases cost and weight. Structural Health Monitoring (SHM) is an approach to continuously monitor structures for damage while they are in operation. The complexity and cost of monitoring large structures where damage can occur anywhere on the structure has so far restricted the application of SHM systems. This thesis presents a method to monitor large composite structures for damage using a simple and reliable approach. Carbon Nanotube (CNT) sheets are used as sensors to detect internal damages in composites. Two CNT sheets separated by a dielectric form the sensor. Impact damage can short circuit the two CNT layers indicating that damage has occurred. Since CNTs have good electrical and thermal conductivity, they will improve the thermal conductivity of composites. Through the thickness thermal conductivity of CNT sheet is characterize (open full item for complete abstract)

Master of Science, University of Akron, 2019, Chemical Engineering

The next generation electronic devices are expected to be small in size and of magnified capacity. Denser packaging of the active components is important to miniaturize the electronic devices. Denser packaging is feasible only when heat generated by heat sources is quickly and effectively carried away to the heat sink. Next generation electronic devices with high performance microprocessors and integrated circuits along with diminished volume have led to major heat dissipation issue. Heat dissipation helps to control the temperature of the electronic devices at a desired level. Heat is dissipated to the heat sink from heat generator by the process of thermal conduction. Due to irregularities on the surfaces of the heat generator and heat sink, air is entrapped, and the air gap is formed in the path of thermal conduction. Air gap disturbs the thermal conduction as air is a really poor thermal conductor with a thermal conductivity of 0.026 W/mK at room temperature. Air acts as a thermal barrier preventing the effective heat transfer between the heat source and heat sink. Different kind of thermal interface materials are used to fill up the air gap between the heat generator and the heat sink to improve thermal conduction. Introduction of thermal interface material can significantly increase the performance of electronic device. In a typical power electronic package, a grease is used as thermal interface material. Thermal conductive paste with high thermal conductivity (much greater than air) fills up all the air gaps between the heat generator and the heat sink to improve the thermal conduction. Development of the thermal conductive paste with low thermal resistance, high thermal conductivity and low electric conductivity is challenging and the most important aspect in today's electronic industries. In the current study, we have tried to overcome this challenge by developing a thermally conductive grease with low thermal resistance, high thermal conductivity and low (open full item for complete abstract)

Doctor of Philosophy, University of Akron, 2015, Mechanical Engineering

Thermoelectric materials exhibit a significant coupling between thermal and electrical transport. Devices made from thermoelectric materials can convert between thermal and electrical energy. System reliability is extremely high but widespread use of the technology is hindered by low conversion efficiency. To increase the practicality of thermoelectric devices improvements are required in both (i) device design and (ii) thermoelectric materials. Advanced thermoelectric analysis developed in this work provides general guidelines for device design by introducing a new set of design factors. The new analytic factors include Device Design Factor, Fin Factor, Inductance Factor, and Thermal Diffusivity Factor. The advanced analysis is applied to two material systems developed in this work. The first system investigated was a composite of WSi2 precipitates in a Si/Ge matrix. The composite was investigated through both solidification techniques and powder processing. The system has a 30% higher figure of merit, a material parameter relating to conversion efficiency, than traditional zone-leveled Si/Ge. The second system investigated was a novel quaternary CoxNi4-xSb12-ySny skutterudite. The system was found to achieve both n- and p-type conduction with tuning of the Co level.

Doctor of Philosophy, Case Western Reserve University, 2013, Chemical Engineering

A new class of high-performance resins combining the molecular structure of both traditional phenolics and benzoxazines is developed. The monomers are synthesized through Mannich condensation reaction of methylol-functional phenols and primary amines, in the presence of paraformaldehyde. The network structure is built utilizing simultaneous addition and condensation polymerization through benzoxazine and resole chemistry. The presence of methylol groups accelerates the polymerization with improved thermal properties of the produced polymer. The polymers show high glass transition temperature, Tg (274-311°C) and excellent thermal stability compared to the traditional polybenzoxazines. The non-isothermal DSC analysis using Kissinger and Ozawa methods show that polymerization reactions of methylol monomer exhibits lower apparent non-elementary activation energy (83.6 and 93.5 KJ/mol) compared to the unfunctionalized monomer (94.1 and 101.4 KJ/mol). The thesis shows an optimum solution to overcome the historic limitations of using phenolic/urethane materials. The limitations include the slow reaction kinetics of the isocyanate and phenolic compounds along with poor thermal stability of the produced urethane linkages. The new approach is based on reacting methylol benzoxazines with isocyanates and polyols to form polybenzoxazine/polyurethane copolymers. The incorporation of benzoxazine in the copolymer shifted the decomposition temperature to (285-300 °C) with char yield of (18-53%), depending on the benzoxazine content. In addition, the thesis deals with the preparation of high thermally conductive coating for electronic components. For this purpose, boron nitride nanosheet (BNNS) is used as a model system to be dispersed in benzoxazine monomer. Composite of the commercial BN embedded into methylol benzoxazine monomer was used as a control. BNNS systems exhibit higher thermal conductivity values than the BN systems. The SEM images show that dispersion and distributio (open full item for complete abstract)

Master of Science (MS), Ohio University, 2012, Electrical Engineering (Engineering and Technology)

Curcumin is a versatile chemical. It is used in food, medicine and electrical engineering. Use of curcumin in medical fields has been concentrated on the treatment of cancer, but it is a traditional spice that has been used in food preparation for millennia. Curcumin has seldom been used in physics, and electronics. In fact, curcumin gained its importance for its under representing ligand suitable for holding metal ions suspended in an insulating matrix of organic polymer. It consists of two regions: The ¿¿¿¿--diketone moiety for holding the metal, and the phenol group for attaching to the organic polymer. Its electronics applications have been focused primarily on the conversion of light to electricity. The unmodified structure of curcumin is not stable enough for photoluminescence because of its severe absorption in 340 nm - 535 nm wavelength range. Surprisingly, modified curcumin structures proved to be photo stabile in the visible range of 420 nm - 580 nm. Recently it was reported that 0.6% efficient photovoltaic material can be achieved using curcumin. In addition, curcumin dyes are chemically stable and eco-friendly. The project began with Dr. Butcher's, Department of Chemistry, Ohio University, suggestion that curcumin might serve as a means for making electrically conducting polymers. Initial work conducted by this research led to the investigation of photovoltaic properties of engineered curcuminated epoxy and ITO glass as a transparent electrode. No photovoltaic behavior was observed, but the changes in resistance noted that were sufficiently interesting to warrant detailed investigation. In the project, we used purified curcumin to prepare a novel copper doped curcuminated epoxy polymer and studied electrical properties at ambient temperature. The Design of Experiments method was applied to this study for the purpose of determining the significance of various constituents on the conductivity. Sixteen compositions were prepared and investigated using a Kei (open full item for complete abstract)

Master of Science, Miami University, 2006, Environmental Sciences

This practicum was carried out along the Great Miami River at Charles M. Bolton well field site 6 corresponding to pumping well 6 owned by Greater Cincinnati Water Works. The aim of the study was to assess the impact of storms and floods on the hydraulic conductance of the bed of the Great Miami River using seepage meters in conjunction with mini-piezometers and the method outlined by Lee (1977). In this study the hydraulic conductivity of the streambed was measured before and after flooding and ranged from 2.53×10-3 to 5.22×10-1cm/s. The streambed conductivity was lower compared to the glacial aquifer conductivity measured by other researchers. The pre-and post-flood hydraulic conductivities were not significantly different (p=0.77).

Master of Science in Polymer Engineering, University of Akron, 2010, Polymer Engineering

Boron Nitride (BN) is widely used in thermal management applications involving thermoplastic polymeric articles. BN platelet agglomerates give higher through-plane thermal conductivity and more isotropic thermal conduction than single crystal powder grades. However, the agglomerates are relatively weak and susceptible to attrition when subjected to aggressive shearing in processing flows. Thus, it is imperative that compounding of BN with polymer and subsequent processing of the compounds should be carried out below a critical shear stress level in order to preserve the agglomerate structures and to obtain isotropic thermal conduction. This study focuses on identification of the critical hydrodynamic stress level for BN agglomerate attrition and its effect on the thermal conductivity of the composites produced by extrusion compounding and injection molding. Two agglomerate grades of BN viz. PT350 and CF400 with different mean particle sizes were used as fillers in polycarbonate (PC) at different filler loadings. Shear experiments were carried out in rotational and capillary rheometers and the status of BN particle breakdown was analyzed using Scanning Electron Microscopy (SEM) images. The results of shear experiments in rheometric flows revealed that morphology of BN particles and thermal conductivity of the composites strongly depended on the shear stress encountered. The particle size distribution and thermal conductivity measurements revealed that considerable breakage of agglomerates occurred during extrusion and injection molding which affected through plane conductivity of the composites. The in-plane conductivity was seen to increase with injection speed due to particle orientation during injection molding. The in-plane thermal conductivity as high as 2.47 W/mK around twelve times higher than neat polycarbonate was obtained with 35 wt% loading of boron nitride. It was also found that polycarbonate filled with 35 wt%PT350 and 25 wt% CF400 showed an increase in (open full item for complete abstract)

Doctor of Philosophy, University of Akron, 2008, Polymer Engineering

In this work, highly conductive carbon-filled epoxy composites were developed for manufacturing bipolar plates in proton exchange membrane (PEM) fuel cells. These composites were prepared by solution intercalation mixing, followed by compression molding and curing. The in-plane and through-plane electrical conductivity, thermal and mechanical properties, gas barrier properties, and hygrothermal characteristics were determined as a function of carbon-filler type and content. For this purpose, expanded graphite and carbon black were used as a synergistic combination. Mixtures of aromatic and aliphatic epoxy resin were used as the polymer matrix to capitalize on the ductility of the aliphatic epoxy and chemical stability of the aromatic epoxy. The composites showed high glass transition temperatures (Tg ~ 180°C), high thermal degradation temperatures (T2 ~ 415°C), and in-plane conductivity of 200-500 S/cm with carbon fillers as low as 50 wt%. These composites also showed strong mechanical properties, such as flexural modulus, flexural strength, and impact strength, which either met or exceeded the targets. In addition, these composites showed excellent thermal conductivity greater than 50 W/m/K, small values of linear coefficient of thermal expansion, and dramatically reduced oxygen permeation rate. The values of mechanical and thermal properties and electrical conductivity of the composites did not change upon exposure to boiling water, aqueous sulfuric acid solution and hydrogen peroxide solution, indicating that the composites provided long-term reliability and durability under PEM fuel cell operating conditions. Experimental data show that the composites developed in this study are suitable for application as bipolar plates in PEM fuel cells.

Master of Science in Materials Science and Engineering (MSMSE), Wright State University, 2024, Materials Science and Engineering

The abundance and the cost-effectiveness of sodium resources have made sodium-ion batteries (SIBs) viable alternatives to lithium-ion batteries. Developing low-cost and high-performance electrolytes is one of the key areas for the advancement of SIB technology. The highly conductive liquid or solid electrolytes have the potential for practical sodium-ion battery applications. Long-term stability, alternative polymers, and full-cell integrations are other avenues that need further research to improve scalability and performance for SIBs. This research covers preparing and evaluating liquid and polymer electrolytes, with a focus on ionic conductivities. Liquid electrolytes were prepared by the dissolution of different sodium salts including NaCl, Na2S, Na2SO3, and NaF in methanol, water, DMF (dimethyl formamide), n-propanol, and DMSO (dimethyl sulfoxide) solvents, in a concentration range from 0.01 M to 0.1 M. It is aimed to investigate the impacts of the solubility, polarity, and concentration on the ionic conductivities. Polymer electrolytes were prepared using the solvent casting technique. The films contained NaCl as the salt and PEO (polyethylene oxide) as the polymer host. The impacts of the two solvents, methanol and DMF, with and without plasticizer EC (ethylene carbonate) on the ionic conductivity of the polymer electrolytes were analyzed. The study validates that optimizing solvent and additive selection are paramount in developing high-performance electrolytes for SIBs.

Master of Sciences (Engineering), Case Western Reserve University, 2025, Macromolecular Science and Engineering

Hexagonal boron nitride is a platelet-like thermally conductive filler commonly used to increase the thermal conductivity of polymers. Good alignment of boron nitride in the in-plane direction is required to create a good network for phonon transport to achieve high thermal conductivity in composite materials. To create good alignment of platelet-like particles, extensional flow is needed, like what is experienced by a polymer melt in a layer multiplication element in forced assembly co-extrusion. As a result, films with A/B structure of hBN + polymer/unfilled polymer were made using layer multiplication co-extrusion. The high degree of alignment and confinement of boron nitride into every other layer led to a higher-than-expected thermal conductivity at relatively low loadings of boron nitride. At only 12.7vol% (25wt%) filler loading, a composite film reached a thermal conductivity of 3.41 Wm-1K-1 which is much higher than was predicted by modeling.

Master of Science, The Ohio State University, 2005, Graduate School

Master of Science, The Ohio State University, 1968, Graduate School

Doctor of Philosophy, The Ohio State University, 2024, Chemistry

The design of next generation electrical and thermal transport materials is of far-reaching importance for myriad applications from thermoelectrics to dynamic transport switching. To that end, axis-dependent conduction polarity and thermal-switching materials hold significant promise. Axis-dependent conduction polarity (ADCP) is a phenomenon in which the electrons (n-type carriers) and holes (p-type carriers) are preferentially conducted along orthogonal directions in a crystal. The driving force for this phenomenon is a large (> 10x) anisotropy in the electron and hole mobilities between orthogonal directions. Herein is discussed the development of the first air-stable, wide bandgap (> 0.4 eV) semiconductor that displays ADCP, orthorhombic PdSe2. The anisotropy in the hole mobilities between the cross-plane and in-plane directions is > 100x, with holes preferentially conducting along the cross-plane direction. Additionally, the onset temperature of ADCP can be controlled via extrinsic doping with Ir and Sb as p-type and n-type dopants, respectively. When the chemical potential is near the valance band (Ir doping), ADCP is not observed up to 400 K. When it is mid-gap the onset temperature is about 350 K. But when it is near the conduction band (Sb doping), the onset temperature can be as low as 100 K. The dopant dependent onset temperature indicates the necessity for both the conduction and valance bands to be populated sufficiently to observe ADCP. Studies in this model system pave the way for further ADCP studies in semiconductors. Solid-state thermal switching is the rapid and reversible control over the thermal conductivity of a material between some low and high value without the need for physical phase changes or moving parts. Topologically non-trivial materials are promising candidates for solid-state thermal switching on account of their anomalous transport properties. Therefore, EuCd2As2 and MnBi2Te4 were studied for their thermal switching potential. Eu (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2024, Nuclear Engineering

Actinide oxide fuels undergo complex and multifaceted transformations during reactor operation, which, if properly understood and accounted for, can significantly enhance the safety and stability of the fuel cycle. A key aspect of understanding these transformations is identifying the critical features of fuel microstructure that impact thermal conductivity. This thermal conductivity is influenced by intricate microstructural, chemical, and thermodynamical processes. Due to substantial thermal variations across the annular pellet, significant microstructural changes occur over short distances, and these processes are highly temperature-dependent. Thus, a coupled approach to simulating the multiscale features of nuclear fuels is essential for predicting the evolution of thermal systems in actinide oxides. While accurately accounting for microstructural changes in nuclear fuels has been crucial to the industry since its inception, localized thermal conductivity measurements have recently emerged as a method to validate thermal conductivity models that have been standard for decades. Novel experimental techniques, offering unprecedented levels of discretization, now capture these localized microstructural trends affecting the thermophysical properties of nuclear fuel. Previous studies on the validation and parameterization of thermal conductivity in nuclear fuels were limited by the measurement scale, often spanning millimeters using techniques such as Laser Flash Analysis. The thermal conductivity microscopes, however, provide micron-scale resolution, enabling more precise validation across the spatial dimensions of nuclear fuels. In this study, radial measurements of porosity, elemental composition, and thermal conductivity of oxide nuclear fuel pellets at various burnups were acquired and analyzed in conjunction with a fuel performance model integrated with the experimental results. The nuclear fuel performance software BISON was used to integrate the multiscale m (open full item for complete abstract)

Master of Science (MS), Ohio University, 2024, Biological Sciences (Arts and Sciences)

Eastern Hellbenders (Crytobranchus a. alleganiensis) have suffered enigmatic, range- wide declines over the past decades. Persisting populations are skewed towards larger, older adults, suggesting that reduced recruitment is responsible for these declines, with degraded water quality, specifically elevated conductivity, implicated as a main contributor. Successful fertilization and the resilience of eggs under high conductivity conditions suggest deleterious effects during larval development. We experimentally assessed the effects of chronic exposure to elevated conductivity (1000 μS/cm) on wild Eastern Hellbender larvae hatched in a lab, as well as the effects of switching from low conductivity (100 μS/cm) to high, and vice versa, on Eastern Hellbenders during early larval development. We assessed mortality over 72 days post-hatching, with half of the larvae switched from their original conductivity treatments to the other over five days beginning at 33 days post-hatching. Chronic exposure to elevated conductivity resulted in significant mortality. Additionally, switching larvae from low conductivity to high resulted in increased mortality, while switching larvae from high conductivity to low increased survival. We also assessed larval morphology and swimming performance and found significant negative effects of chronic exposure to elevated conductivity on both body mass and multiple measures of morphology (length and width). We observed similar effects in animals switched from low conductivity to high, while switching animals from high conductivity to low resulted in only marginally increased mass and morphological measures, demonstrating their inability to compensate for initially depressed growth rates even after being returned to more optimal conditions. Despite altered size and morphology, elevated conductivity did not impact locomotor performance, though switching conductivities, regardless of direction, did result in increased burst distance. We measured who (open full item for complete abstract)

Doctor of Philosophy, University of Akron, 2024, Polymer Engineering

In this work, High Density Polyethylene (HDPE) composites were made using Torrefied Soybean Hulls (TSBH) and Carbon Black (CB) to study the interactions affiliated with the TSBH content for as-received as well as size-reduced particles. The Milled TSBH (MTSBH) was shown to integrate well at low loadings, but showed signs of favoring filler-filler interactions over filler-matrix interactions, reducing the overall effectiveness as the loadings increased. Rheological testing showed that the higher-loaded MTSBH composites behaved similar to composites with larger particles as the loading increased, indicating that clusters had formed. Unmilled TSBH (UTSBH) showed good mechanical strength, but the particle size was shown to limit its ability to integrate into the material, even at low loadings. The addition of CB was shown to have the most impact on the low loading MTSBH composites, where the MTSBH-CB interactions were shown to influence the filler network in electrical resistance testing where a nonlinear trend was observed in the composite resistivity with the addition of MTSBH. In UTSBH composites, there were less signs of CB-UTSBH interactions due to the relatively large particle size. To contrast the hydrophilic matrix behavior of HDPE, Nylon-6 (PA6) was used as a matrix for the TSBH composites. In cases where either TSBH filler was used, the composite performance was shown to improve to a greater degree than in the case of HDPE due to the hydrophilic groups contained in the PA6 backbone. Similar to the HDPE composites, the TSBH particles showed a lack of effectiveness at higher filler loadings, though MTSBH showed more effective integration which indicates that this is a result of particle size. The CB and MTSBH showed synergistic effects with high CB and low MTSBH loading during cyclic tension testing, where the increase in strain energy density required for a test was less when the CB was present that when it was not. This effect was seen throughout the mono (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2023, Materials Science and Engineering

This thesis reports experimental data on the transport properties of ferroelectric and ferromagnetic solids, as well as topological insulators. The analogies between the thermal perturbations of ferroelectric and ferromagnetic order are explored from a fundamental point of view. While ferromagnetic order is the object of an established field of study, spin caloritronics, the study of perturbations in ferroelectrics stands to establish a new field, polarization caloritronics. This new field, following in the footsteps of its predecessor, has the potential to impact thermoelectricity, heat controlling devices and possibly phonon-based logic. The first subject of this dissertation is a new quasiparticle, the ferron, defined as the elementary thermal excitation of polarization in a ferroelectric material. Likening the ferron to the quantum of a spin wave, the magnon, we measured the ferronic thermal conductivity in lead zirconium titanate (PZT), a well-established ferroelectric material. With the assistance of resonant ultrasound spectroscopy (RUS) to establish the electric field dependent sound velocity, we determined that optical phonons hybridize with acoustic phonons assisting in the formation of a polarization-lattice coupled phonon, coined the ferron. The ferron theory states that the electric field dependent sound velocity and thermal conductivity can be predicted with three material properties: the Gruneisen parameter which quantifies the anharmonicity of the phonon dispersion with respect to volume changes, and d33 and d31, which are the piezoelectric coefficients which quantify the parallel and perpendicular strain of the system in an electric field, respectively. The predicted field dependency using published values for PZT agreed well with our observations. To further test this theory, we performed RUS and thermal conductivity measurements on a relaxor ferroelectric, a solid solution of lead magnesium niobate and lead titanate (PMN-PT). Here, the theory (open full item for complete abstract)