Doctoral and Masters

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Next Generation Hydroxyapatite Bone Grafts: Copper-Inclusion and Photocurable Composites
(New York State College of Ceramics at Alfred University. Inamori School of Engineering., 2023-12) Kucko, Sierra; Keenan, Timothy; Sundaram, S.K.; Clare, Alexis; Wren, Anthony
Orthopedic infection is a massive threat whose prevalence and invasiveness increases in parallel to a rapidly aging population. The rise in antibiotic-resistance deepens this threat to a level where infection is projected to become a leading cause of death in the next two decades, thus substantiating the need for alternative therapies. A shift from treatment solutions towards prophylactic practices will likely pave the way for the next generation of bone grafts. Hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP), the most widely used bone grafting materials clinically, do not have any inherent antimicrobial properties. Transition metals, such as Cu, are known to be antibacterial and have thus been incorporated into HA or β-TCP for that purpose, which is the motivation for the following work. Since ceramic particles are typically delivered as a grafting material in composite form, a wide range of HA- and β-TCP-polymer composites are reviewed extensively, including the various fabrication methods that have been developed recently. Clinically implemented composites are surveyed, with commercially available products and their respective uses highlighted. Robust structural and chemical analysis of these types of materials is severely lacking, which limits our understanding of their antibacterial nature and leaving some conclusions to be drawn based upon conjecture. Our fundamental understanding of any antibacterial effect relies on the understanding of the tenancy of substituted ion(s) and its correlation to key physical, structural, and chemical properties. This gap in knowledge leaves room for a substantial body of work designed to explore Cu-inclusion in an HA lattice. Motivated by this, a series of Cu-containing HA (CuHA) was synthesized via aqueous co-precipitation. This work tracks changes in lattice parameters with increased Cu content, conducted through Pawley fits of X-ray powder diffraction (XRD) patterns. High-temperature in situ XRD followed by quantitative phase identification assessed the thermal transition to Cu-containing β-TCP. As Cu target incorporation increased from 0-5 mol% (actual 0-1.96 mol%), there was an observable increase in stoichiometry, carbonate removal, and resistance to thermal phase transition. Particle size, surface area, and degree of crystallinity measurements revealed significant deviation in surface area corresponding to only a 1.96 mol% increase in Cu content, yet miniscule modifications to crystallinity and particle size were observed. Heat treatment of CuHA to form Cu-containing biphasic calcium phosphate (CuBCP) enabled Cu release in aqueous solution whereby its CuHA counterpart showed no Cu release. Agar diffusion and time-based bacterial broth analyses were conducted against gram-positive and gram-negative strains of bacteria for CuHA and CuBCP. Some key structure-property relationships have been identified through this work. Calcium phosphates, albeit adept at repairing hard tissue, are limited to non-load-bearing sites. Additionally, they are difficult to retrofit in the often unusually shaped bone defects. Ceramic-polymer composites are a better biological mimic of bone tissue, which itself is a composite. Polymerized high internal phase emulsion (polyHIPE) is a stochastic fabrication process that elicits highly interconnected and porous scaffolds, ideal for bone tissue regeneration. A 4-armed star-shaped photocurable polycaprolactone (PCL) is synthesized and functionalized with methacrylate end-groups to be used for UV-cured polyHIPE. The resultant polymer is characterized via Raman spectroscopy, attenuated total reflection- Fourier transform infrared spectroscopy (ATR-FTIR), and mass spectrometry (MS) to gain insight into the architecture of the macromolecule. Cured polyHIPEs exhibited excellent porosity, open-cell morphology, and interconnectedness, with pore size diameter of 108 ± 57μm. Efforts culminated with the attempted manufacture of a proof-of-concept next-generation bio-composite by incorporating HA into the polyHIPE. HA underwent surface modification to improve dispersion in the oil phase. However, HA caused a complete phase inversion of the emulsion. Nonetheless, the star-shaped PCL is characterized and this proof-of-concept bio-composite is described.
The Effects of Residual KNO3 and Ion Exchange Induced Crack Closure on Indented Glass
(New York State College of Ceramics at Alfred University. Inamori School of Engineering., 2023-11) Tindle, Madison; LaCourse, William; Möncke, Doris; Clare, Alexis
The objective of this body of work is to investigate the fatigue response of ion - exchanged aluminosilicate glass containing pre-exchange indentation flaws. Previous work found that residual potassium nitrate (KNO3), the ion exchange material, remained in the flaw after an initial washing of the parts. The remaining material at the flaw tip is thought to prevent humidity or water from penetrating to the crack tip and slows crack propagation thus increasing the failure load. To test this hypothesis two flaw depths of 25μm and 90μm, and three washing conditions were tested after the parts were ion-exchanged at the same time and temperature. The first condition is the control set where the samples just underwent an initial washing to remove salt on the surface post ion exchange. The second condition was ultrasonic cleaned. The third condition was also ultrasonic cleaned and mineral oil was added to the flaw to act as a humidity barrier. The fatigue response for each condition was evaluated using a ring-on-ring method at varying strain rates to calculate the fatigue response. The sample with small flaws around 25μm in depth showed no difference in fatigue response between the control and just ultrasonic cleaned. The driving force for the increased strength is from the ion exchange at the flaw tip and not the material left in the flaw acting as a humidity barrier. The samples with the larger flaws around 90μm did show some variation in the failure mechanism and failed at low loads that were closer to the non-ion-exchanged failure loads. When these parts were looked at under SEM NaCl was found on the surface of the flaws, which led to some exploration in diffusion time, expansion, and contamination during the ion exchange process. The crack width was estimated to evaluate the volume of salt in the flaw as well as determine the feasibility of the crack closure. The two most plausible hypotheses were the salt refresh rate or contamination. Further testing is needed to answer these questions.
Additive Manufacturing of Hybrid Composites for Flexible Electronic Application
(New York State College of Ceramics at Alfred University. Inamori School of Engineering., 2023-08) Gao, Yuqi; Ding, Junjun; Wu, Yiquan; Wren, Anthony; Tidrow, Steven
Material extrusion 3D printing is capable of fabricating complex macrostructures and designing microstructures for next-generation flexible electronics. Thick electrodes are promising to increase the mass loading of active materials in supercapacitors, but the 3D geometries and microstructures in thick electrodes still hinder the development with high electron and ion exchange rate and accessible active sites. The scaffold 3D electrodes of reduced graphene oxide:manganese oxide/carbon nanotube (rGO:MnOx/CNT) with highly-ordered microstructure were manufactured by material extrusion 3D printing, freeze-drying, and thermal treatment. The increasing amount of MnOx/CNT composites improved the areal capacitance. And the rate capability remained stable at different thicknesses. A 2 mm thick rGO:MnOx/CNT (weight ratio 5:3) electrode exhibited an excellent area capacitance contributed by the highly ordered rGO networks. Fiber-shaped supercapacitors are attractive as an energy storage unit due to their excellent flexibility. However, fabricating robust fibers with large yields remained a challenge. The present study fabricated the core-sheath fibers through coaxial extrusion printing. Carboxymethylcellulose sodium salt (CMC) slurry with controlled rheological properties was extruded from the outer channel, while GO slurry was extruded from the inner channel simultaneously. The followed freeze-drying process protected GO sheets from agglomeration, providing more efficient chemical reduction. After reduction, rGO sheets were separated and expanded to fill in the CMC sheath, which eliminated the delamination between the CMC sheath and rGO core. Apart from the 1D core-sheath fiber electrode, 3D printed electrode with core-sheath structure provided a solution for the development of thick supercapacitors. Specifically, 3D thick rGO/CNT-rGO/CNT/MnO@CNT (rGC-rGCMC) electrodes with controlled lattice architectures, core-sheath structure, and hierarchical porosity were prepared. The electrodes with different volume ratios of core to sheath, including 100%-0%, 0%-100%, 20%-80%, 30%-70%, 40%-60%, and 50%-50%, were investigated to explore the influences of core-sheath structure on thick electrodes. All capacitance decays from core-sheath electrodes (20%-80%, 30%-70%, 40%-60%, and 50%-50%) were smaller than rGCMC (0%-100%) electrodes, indicating the improved rate capability from the core-sheath structure. Compared 30%-70% core-sheath electrodes with electrodes made of homogenous 30% rGC and 70% rGCMC mixture (30%+70%), lower capacitance (382.27 mF cm^-2 and 25.66 F g^-1 at 0.5 mA cm^-2) of 30%+70% mixture electrode without core-sheath structure suggested less efficiency to harvest electrons from the redox reactions. Electrochemical impedance spectroscopy (EIS) data further supported and explained the resistances of thick electrodes with different volume ratios.
Nanoscale Dipole Engineering of BaTiO3 Using Dy3+-Ta5+ and Ho3+-Ta5+ Dipole Pairs
(New York State College of Ceramics at Alfred University. Inamori School of Engineering., 2023-05) Pellegrino, Victoria; Tidrow, Steven; Pilgrim, Steven; Sundaram, S.K.
Barium titanate (BaTiO3) is the most widely used base material for electroceramic capacitor technology. Previously, experiments conducted within the New York State College of Ceramics (NYSCC) Laboratory for Electroceramics (LEC) at Alfred University have demonstrated that substituting dipole pairs for the titanium ion in the center of the octahedral cage in BaTiO3 can enhance the electrical properties of the material for storing charge and provide the enhanced properties over a larger operating temperature range as compared with pure BaTiO3. This thesis investigates the properties of BaTiO3 - based material processed using dipole engineering at the nanoscale, through substitution of Dy3+-Ta5+ and Ho3+-Ta3+ dipoles for Ti4+, to form Ba(Dy,Ta)xTi1-2xO3 and Ba(Ho,Ta)xTi1-2xO3, respectively. The dipole pairs maintain charge neutrality, but desirably possess higher polarizability values than the original Ti4+ ion; thereby, leading to enhancements in electrical properties. The substitutions were performed through a solid-state reaction following the stoichiometric equation: Ba(Ḇ3+, Ta5+)xTi1-2xO3, with x = 0.0000, 0.0025, 0.0050, 0.0100, 0.0250 and 0.0500, and Ḇ being the Dy3+ or Ho3+. The material properties were investigated using room temperature and energy dependent characterization tools to improve understanding of the effects of dipole pair substitutions, including concentration dependence. Material characterization has been completed using: room temperature x-ray diffraction to determine room temperature structure, phase purity and lattice parameter; temperature dependent resistivity to determine intrinsic material resistivity and activation energy; impedance - inductance - resistance (LCR) to determine temperature and frequency dependent relative permitivity; temperature dependent Raman to determine thermally induced structural phase transitions; and, scanning electron microscope to determine microstructure, and grain size. Analysis indicates that a range of a priori predicted properties, using the new simple material model (NSMM) as well as projections from prior results, occur. Further, novel Raman properties are also observed, including a BaTiO3 - like lattice and a second lattice associated with either the individual ions Dy3+ and Ho3+ or the Dy - Ta and Ho - Ta dipole pairs within Ba(Dy,Ta)xTi1-2xO3 and Ba(Ho,Ta)xTi1-2xO3, respectively. Importantly, a decoupling of the relative permitivity peak from the structural phase transition temperature is demonstrated.
Manipulation of Lanthanoid Luminescence in Silicates
(New York State College of Ceramics at Alfred University. Inamori School of Engineering., 2023-06) Bellows, Charles; Clare, Alexis; LaCourse, William; Loucks, Roger; Möncke, Doris
The luminescent properties of several lanthanoid ions were examined when doped into silicate glasses. Moreover, the effect of visible colorants, common in the world of glass art, on said luminescence was studied. Several potential applications are described, including aesthetic uses in the realms of art and industry. Luminescent microsphere production as an add-value sink for waste glass is detailed and a novel process was developed to incorporate persistent luminescent material into waste glass and other 'previously melted' glasses via a 'sinter-esque' fusion method with promising results. A glass with a unique dopant combination was developed to showcase a visible color contrasted with a UV-induced luminescent color. Glass medallions utilizing this composition were manufactured for use in the podium medals of the 2023 FISU World University Games Winter. Additionally, a specific case study was investigated regarding one of the lanthanoid-transition metal codopant compositions. The combination of cerium and manganese ions in silicate glass composition exhibits a novel optical effect: luminescent opacity. Under visible light illumination, this composition appears transparent purple; similar to other silicates containing the Mn3+ ion. As with other silicates doped with Ce3+ and Mn2+ ions, this composition also luminesces visible light under ultraviolet light. Unlike similar compositions, under said ultraviolet light the glass acquires a turbidity not seen under visible light. when the ultraviolet source is removed, the glass returns to a transparent purple rather than maintaining its opacity.
Upstate New York Wind Farm Utilization - Towards Black Start
(Alfred University. Inamori School of Engineering., 2023-07) Alanazi, Omar; Wang, Xingwu; Zhan, Junpeng; Lu, Dan
Considering wide available wind farm resources in Upstate New York, this work attempted to seek a new application: possibilities in black start operations. Before reaching such goal, one needs to plan the possibilities by surveying power grid unique conditions in this area. Such planning may avoid future additions of power generation facilities based on petroleum energy sources, transitioning towards a more sustainable and resilient energy system. Thus, this work was focusing on the feasibility of such future plan, and examined the wind farm power levels and locations, along with population center electricity usage. Preliminary simulations were done with MATLAB/Simulink and OPAL-RT. Analyses of voltage fluctuations, power delivery to a desirable load, switching events and subsequent instability/stability reactions, and frequency variations were evaluated. In particular, four different cases were considered for a topology involving four wind power generators and four major trunks. Some trunks had two end loads: upper and lower loads. All four trunks were connected to each other. In case one, the end load for trunk 1 was considered. In case two, another load for trunk 2 near generation was considered. In case three, the upper end load for trunk 3 was considered. In case four, the lower end load for trunk 3 was considered. The voltage uncertainty of most loads was within ±10% and the frequency was 60 ± 0.5 Hz. Briefly, this work simulated the transient of switching the loads from one trunk to another.
Solid State Epitaxial growth of Bulk and Thin Film Single Crystals
(New York State College of Ceramics at Alfred University. Inamori School of Engineering., 2023-02) Milisavljevic, Iva; Wu, Yiquan; Sundaram, S.K.; Tidrow, Steven; Wren, Anthony
Recent studies have shown that many challenges encountered in conventional single crystal growth methods, including high production costs, can be overcome using the solid-state single-crystal growth (SSCG) approach, which has been recognized as a simple and cost-effective alternative for obtaining single crystals. Thus far, the development of the SSCG technique has enabled the fabrication of single crystals with complex chemical compositions and even incongruent melting behavior through the use of a recently proposed mechanism of grain boundary migration known as the "mixed control mechanism" and the associated principles of microstructural evolution. The first chapter of this thesis presents the study of the mechanisms and kinetics of this novel single crystal growth technique using undoped and Nd-doped yttrium aluminum garnet (YAG and Nd:YAG) optical materials as the model systems. The results of the study have broadened the knowledge of the SSCG by demonstrating the effects of different parameters, including the application of external pressure during processing, doping, temperature, and oxygen partial pressure that can be used to control and predict the quality of single crystals and grain growth behavior during the single crystal conversion process. Further on, the progression of this project led to the study not only on bulk YAG single crystals but also thin (single crystal) YAG and Nd:YAG and aluminum gallium oxide (β-(AlxGa1-x)2O3) epitaxial films with the aim of extending the collection of potential applications of these well-known optical and optoelectronic materials. Good-quality epitaxial films of YAG and Nd:YAG on YAG single crystal substrates (chapter II) and β-(AlxGa1-x)2O3) on sapphire substrates (chapter III) were generated and characterized in terms of their structural, chemical, and optical properties using a less studied sol-gel spin-coating film fabrication approach. The results of the study on the wide-bandgap semiconductor β-(AlxGa1-x)2O3 films on the effects of tuning the bandgap by changing the Al concentration (i.e., bandgap engineering), substrate orientation, and rare-earth doping collectively demonstrating the effectiveness of a simple and inexpensive sol-gel spin-coating deposition technique to fabricate novel materials and compositions with tunable properties for a broad range of next-generation electronic, optoelectronic, and photonic devices.
Structural Study of Alkaline Earth Aluminosilicate Glasses by Vibrational Spectroscopy
(New York State College of Ceramics at Alfred University. Inamori School of Engineering., 2022-06) Hunt, Jennifer; Möncke, Doris; Clare, Alexis; LaCourse, William
Understanding the structure of alkaline earth aluminosilicate glasses is important for many applications including better interpretation of the structure property correlation and subsequent development of commercial glasses for various technologies including damage resistant and stronger glasses for consumer electronics, photonics, nuclear waste sequestration, bioglasses, and new glasses in life science. Changes in the coordination of aluminate polyhedra, connectivity and the degree of polymerization of the network impact the materials physical properties. The structure of two alkaline earth aluminosilicate glass series is studied by Infrared and Raman spectroscopy. The glasses contain either barium or magnesium oxide as modifier components. Multiple glasses were available for each series with the formula: xMO-yAl2O3-(100-x-y)SiO2. The aluminum coordination was quantified by 27Al-NMR, confirming a predominant four-fold coordination. However, the high field strength of Mg2+ compared to Ba2+ has a significant impact on the aluminum speciation as more five-fold coordinated Al, up to 14%, as well as higher disporportionation in the glass and more non-bridging oxygen ions in the Mg-glasses. Nevertheless, the higher crosslinking strength of Mg2+, is reflected in a higher Tg. The magnesium coordination was deduced from oxygen polarizabilities and found to be closer to six-fold coordinated. Increasing non-bridging oxygen formation with increasing modifier, both Mg and Ba, is seen by the increasing peak intensities of the Q2 and Q3 modes for both glass series, resulting in a decrease in connectivity of the network with increasing modifier content.
Analysis of Earthquake Impact on Solar Houses via Finite Element Method - ABAQUS
(Alfred University. Inamori School of Engineering., 2017-09) Ding, Ding; Wang, Xingwu; Leigh, Wallace; Rosiczkowski, Joseph
Solar PV systems may be considered in areas affected by earthquakes. However, such solar systems should be designed to resist earthquakes. The impacts on solar systems will be studied as the first step. Earthquake generates the most extreme vibration as a natural disaster. An increasing number of active solar PV systems are being installed on solar houses located in earthquake zones. The impact of earthquakes on these solar homes needs to be assessed as these facilities are relatively new. With an earthquake and sunlight occurring simultaneously, the solar PV modules may still generate electricity. Yet, there is concern that the wires may short circuit due to wires crossing path, which creates a fire hazard. For solar house applications, there is no single code/regulation/standard dealing with earthquake safety in California. Some houses with smaller roof slopes are having solar panels rest on the roofs, thereby using frictional forces to restrain the solar harvesting equipment. The purpose of this study is to evaluate the possibilities of damage due to earthquakes. According to the earthquake analysis, earthquakes might cause two events in sequence: one, exposing the bare metal wires, and two, shorting two leads. With flammable materials nearby, a fire may be started due to the two situations mentioned up above. Researchers normally invest in a significant amount of time and money for quality verification of products; the most common structural analysis is used in shocking and striking experiments. In order to improve safety assurance, manufactures expect to make more environmental-friendly and safer products in a short amount of time. With the purpose of enhancing shock resistance and seismic resistance, traditional methods are used to conduct physical experiment for finding solutions. Thus, a process of design, manufacture, tests and re-design are required. This procedure will waste a significant amount of man power and material resources. On the other hand, due to the limitation of the equipment's size, quality and price, physical experiment is beset with difficulties. Taking advantage of using FEA simulation tests can make up for the deficiency of this challenge. FEA software could finish simulating and getting results from the computer model before the sample was created. This will give researchers an advanced knowledge in impact resistance and antiknock characteristics. This will help cut down the research period, maximize use of research funding, and heighten safety and practicability. Utilizing the FEA software, this thesis analyzes and simulates the potential damage due to material failure or bare wire metals suffering from seismic acceleration. In this study, a dynamic earthquake simulation was conducted on solar houses. Finite Element Analysis was performed to obtain the variation of stress magnitude at critical locations.
3D Printed Ceramics After ISS Spaceflight
(Inamori School of Engineering, Alfred University., 2022-09) Bailey, Alexander; Wang, Xingwu; Clare, Alexis; Rosiczkowski, Joseph
This work characterizes 3D printed ceramics after space flight aboard the ISS. Along with water immersion and mercury immersion testing, visual data was collected via SEM, AFM and TEM evaluation. Bulk resistivity was measured via two-point contact probe methods. Cumulative radiation dosage was approximated with data collected from NOAA's GOES system. The SEM micrographs did not provide data for bubbles in the glassy phases of the material, but the TEM data showed bubbles in the polycrystalline structure of the control and experimental batch A specimens. The bulk resistivity testing ultimately revealed that the experimental specimens became less thermally dependent when temperatures varied from 50 °C to 75 °C. This work indicates the need for longer space experiment and radiation exposure durations. Of the two sample batches evaluated, the batch A variant shows promise for future study.
Transparent Gallium-Based Oxide Ceramics
(New York State College of Ceramics at Alfred University. Inamori School of Engineering., 2022-05) Zhang, Guangran; Wu, Yiquan; Tidrow, Steven; Ding, Junjun; Wren, Anthony
Transparent ceramics have been developed and studied for more than 50 years; however, very few efforts have been made in making transparent ceramics semiconducting. Gallium-based oxide materials including, β-Ga2O3 and MgGa2O4 are one of the few materials being considered for semiconducting transparent oxide applications, and which attract significant attention due to their potential as electronic materials with unprecedented performance. This study provides preliminary experimental results on the fully densified (transparent) β-Ga2O3, β-(AlxGa1-x)2O3 and MgGa2O4 ceramics successfully fabricated via the Spark Plasma Sintering (SPS or Pulsed Electric Current Sintering) approach. Both β-Ga2O3 and β-(AlxGa1-x)2O3 have a monoclinic crystalline structure which leads to non-isotropic refractive index. Dense grain structure and small grain size are the two key requirement for obtaining optical transparency in these two material systems. MgGa2O4 belongs to the spinel family with a cubic crystalline structure that do not suffer from birefringence and small grain size is no longer needed as a solution to this problem. Gallium oxide compound (β-Ga2O3 and MgGa2O4) are very reactive at high sintering temperature, which may lead to the reduction reaction when in contact with graphite or exposed to the vacuum environment. To avoid this problem, Mo foil and BN powder have been applied to reduce such reaction. In addition, BN has also served as a buffer layer, which absorbed the thermal and mechanical shock during SPS processing, which have been thought to be the cause of cracking in many sintered ceramic samples at the very end of the sintering process upon cutting off the electrical power supply. High total transmittance of 84% has been achieved in the non-cubic β-Ga2O3 transparent ceramics at 1000nm, whereas high in-line transmittance of 73.3% at ~1.2 µm has been demonstrated in cubic MgGa2O4 transparent ceramics. Detailed procedures on how to fabricate these transparent ceramics are presented in this work. Characterizations results related to to optical properties of fabricated transparent ceramics (photoluminescence, thermoluminescence) are presented to demonstrate potential applications. Overall, it is believed that the transparent ceramics mentioned here will bring new opportunities to the transparent ceramics field, especially for electro-optic applications.
Surface Area Reduction and Two Step Sintering of Alumina
(New York State College of Ceramics at Alfred University. Inamori School of Engineering., 2023-02) Delia, Daniel J.; Carty, William; Tidrow, Steven; Wu, Yiquan; Keenan, Timothy
Surface area reduction trajectories were examined for calcined alumina powder over a range of thermal profiles. Variations in trajectory are explained through experimental demonstrations of blended coarse and fine particle alumina systems. This work demonstrates that (1) nanoparticles do not appear to assist conventional sintering, as the nanoparticle surface area drops precipitously with minimal increase in density, and (2) the forming method does not contribute, nor control, surface area reduction during alumina sintering. Surface area reduction trajectories of >99.9% purity α-alumina powders with various sodium additives levels are compared to a commercial Bayer processed alumina powder to assess the role of sodium on surface area reduction with heat treatment. The results demonstrate that the surface area reduction trajectories of α-alumina are dictated solely by particle size and are independent of the presence of impurities over the range of chemistries studied, indicating that Na impurities do not appear to enhance surface area reduction. Two step sintering of a calcined alumina powder was investigated. A range of green densities were generated and evaluated, to address the role of processing in two step sintering. Both as received and milled powders achieved relative densities surpassing 99% through two step sintering with the lowest ratio of measured grain size with respect to initial particle size(D50) was observed to be 1.5. Discontinuous grain growth features were observed within a fine matrix for milled powder. The sintering of graded particle size distributions of alumina were evaluated for dispersed and flocculated systems. Two step sintering (TSS) of a matrix phase composed of fine particles was attempted with respect to the percolation threshold of coarse and medium particles. Relative density and microstructural evolution were evaluated to assess the role of processing and forming relationships with respect to constrained sintering conditions linked to the percolation threshold of large particles.
Investigation and Primary Fabrication of Strontium-Copper-Doped Sol-Gel Bioglass for Soft-Tissue Repair
(New York State College of Ceramics at Alfred University. Inamori School of Engineering., 2022-12) Perry, Danielle L.; Wren, Anthony; Keenan, Timothy; LaCourse, William
Several studies have reported the use of either strontium (Sr2+) or copper (Cu2+) as bioactive glass dopants however, incorporating both dopants into a bioactive glass composition for the use of soft tissue regeneration remains to be accomplished. Both strontium and copper encourage soft tissue bonding to bone and present angiogenic and antimicrobial properties, respectively. In the current study, the objective was to synthesize strontium and copper-doped bioactive glasses via the sol-gel processing technique and to characterize the structure of the material along with evaluating the antibacterial properties of each bioactive glass. Bioactive glasses synthesized using the sol-gel processing technique have the potential to create high levels of purity and homogeneity while also allowing for a variety of pore structures ranging from nanometers to millimeters. The bioactive glass samples were characterized using various X-ray techniques, vibrational spectroscopy, thermal analysis, and particle size analysis methods. The antibacterial efficacy of the bioactive glasses was examined using multiple methods including, agar diffusion and broth dilution tests which were conducted on the bioactive glass frit and then fabricated into thin films using Polycaprolactone (PCL) and analyzed again using SEM/EDX. This research primarily focuses on understanding the structure and properties of strontium and copper-doped bioactive glasses but gives insight into the materials' role in soft tissue repair and regeneration. The material's intended function would be to augment the insertion points of ligaments, like the Anterior Cruciate Ligament (ACL), and to facilitate the recruitment of new cells to increase healing times after reconstruction.
Structure-Terahertz Property Relationship and Ultrafast Laser Modification in Borosilicate, Tellurite, and Chalcogenide Glasses
(New York State College of Ceramics at Alfred University. Inamori School of Engineering., 2022-12) Tostanoski, Nicholas J.; Sundaram, S.K.; Möncke, Doris; Clare, Alexis; LaCourse, William
This thesis is focused on developing structure-terahertz (THz) property relationships for three distinct glass families, i.e., oxide borosilicate, oxide tellurite, and non-oxide chalcogenide glass families. A comprehensive structural study has been carried out using spectroscopy techniques, e.g., nuclear magnetic resonance (NMR), infrared (IR), and Raman spectroscopy. THz time-domain spectroscopy (THz-TDS) is used to record refractive indices at THz frequencies. Unique structure-THz property relationships are observed for borosilicate, tellurite, and chalcogenide glass families. Sodium borosilicate glasses with a depolymerized glass network composed of [BO4]−, Q4, and Q3- structural units and danburite and reedmergnerite borosilicate ring units with mixed bonding and an interconnected network measure higher THz refractive indices than polymerized networks. Sodium tungsten tellurite and lanthanum tungsten tellurite glasses have higher THz refractive indices correlated to a glass network with substantial TeO2 and WO3 content with mixed Te-O-W linkages and TeO2- or WO3-rich content with homonuclear Te-O-Te or W-O-W linkages, respectively. Unary, binary, and ternary chalcogenide glass systems record a range of THz refractive indices ultimately controlled by and, therefore, elemental composition, structural units, and network. Arsenic sulfide, arsenic selenide, germanium selenide, and germanium arsenic selenide glass systems record the maximum THz refractive index at = 2.4 for As40S60 and As40Se60, = 2.8 for Ge40Se60, and r = 2.5 for Ge10As30Se60, respectively. High-repetition rate femtosecond laser irradiation of sodium borosilicate glasses supports depolymerized glass networks with no change in NMR signal but larger change in the THz refractive indices. Low-repetition rate femtosecond laser irradiation of arsenic sulfide and arsenic selenide chalcogenide glasses measure minimal structural changes and varying degrees of THz refractive indices changes. Linear visible-THz refractive indices correlation in the sodium borosilicate glass system shows higher measurable refractive indices for depolymerized borosilicate networks and LWIR-THz refractive indices correlation in the chalcogenide family shows linear, nonlinear, and anomalous behaviors. Our results reveal the ability to customize the glass family, system, and composition to design a glass with targeted THz optical properties and the use of ultrafast laser irradiation to modify glass structure and THz properties.
3D Printing Silver- and Copper-Doped Hydroxyapatite Scaffolds for Use as Bone Substitute
(New York State College of Ceramics at Alfred University. Inamori School of Engineering., 2022-08) Wallisch, Abigail; Keenan, Timothy; Ding, Junjun; Sundaram, S.K.
With the objective of 3D printing antibacterial bone scaffolds in mind, silver- and copper-doped hydroxyapatite was synthesized through precipitation. The formulation was created with the intention of ten percent dopant substitution in calcium sites. The resulting solid was then milled into to a powder. Phase identification through X-ray diffraction verified the structural composition was hydroxyapatite. Elemental analysis through X-ray fluorescence (XRF) showed the silver-doped powders had 0.3 atomic percent dopant and the copper-doped powders had 1.1 atomic percent dopant, both below the expected goal of 2.7 atomic percent. Secondary electron imaging through scanning electron microscopy provided visualization of porous particles with a wide particle size distribution. Energy dispersive spectroscopy (EDS) showed little evidence of any detectable dopant concentration in the powders, which was consistent with the low dopant content detected through XRF. Particle size analysis through dynamicc light scattering revealed mean particle sizes of 2.2 μm and 1.2 μm for the silver-doped and copper-doped hydroxyapatite samples, respectively. Surface area analysis through the Brunauer-Emmett-Teller method measurements reported 80.0 ± 0.2 m²/g for the silver-doped sample and 342.0 ± 0.6 m²/g for the copper-doped sample. The powders were sent to Lithoz America for slurry preparation using their proprietary recipes. The porosity and agglomeration of the powders proved to be an obstacle for achieving a slurry with an appropriate solids loading for Lithoz's lithography-based ceramic manufacturing system. After a series of failed attempts, it was discovered that the powders' agglomerates were absorbing the resin. As a result, the effective solids loading of the slurries widely strayed from the measured solids loading. With this added knowledge, both powders were successfully prepared into printable slurries. Both slurries were printed into nine scaffolds, all 10 mm in length, 10 mm in width, and 5 mm in height. Both compositions underwent curing complications during the run. Scaffolds were then cleaned, with difficulty, using the Lithoz proprietary solvent, LithoSol 20. They underwent three firing cycles: preconditioning, debinding, and sintering. The preconditioning cycle was held at a maximum temperature of 120°C for 72 hours, the debinding cycle was held above 600°C for 9 hours with a maximum instantaneous temperature of 1000°C, and the sintering cycle was held at a maximum temperature of 1100°C for 2 hours. After sintering, the scaffolds were considerably smaller in size. The shrinkage of the silver-doped scaffolds was ~35% in the XY directions and ~30% in the Z direction. The shrinkage of the copper-doped scaffolds was ~40% in the XY direction and ~35% in the Z direction. The Archimedes density was calculated to be 2.01 g/m³ for the silver-doped scaffolds and 2.20 g/m³ for the copper-doped scaffolds, both densities higher than that of human bone. EDS data indicated a lack of homogeneity within the silver-doped scaffolds and phase separation in the copper-doped scaffolds. The silver-doped scaffolds consisted of regions that ranged in concentration from undetectable amounts of silver to 6.25 atomic percent silver. Conversely, the copper-doped scaffolds had copper-rich deposits with 56.26 atomic percent copper and a region with an undetectable copper concentration. Scaffolds were tested for antibacterial behavior through exposure to Staphylococcus aureus, a gram positive species of bacteria, and Escherichia coli, a gram negative species of bacteria. These tests showed little evidence of antibacterial activity. Each inhibition zone for the twelve tested scaffolds was 0mm. It was concluded that this was a result of multiple factors: non-homogeneity, agar levels in the petri dish, and low dopant concentrations. In order to achieve a viable antibacterial bone substitute customizable to a patient's needs, a lower density, a higher degree of homogeneity, and a higher dopant concentration must be achieved in 3D-printed parts. Additionally, achieving a controllable and adjustable density is necessary for meeting the needs of a variety of patients.
High-Temperature Diffusion of Potassium in Silica
(New York State College of Ceramics at Alfred University. Inamori School of Engineering., 2022-04) Schrock, Benjamin; LaCourse, William; Clare, Alexis; Möncke, Doris
This work focuses on determining the diffusion coefficient of potassium in silica at high temperatures. Understanding this diffusion helps predict the final profile of optical fiber. This work also investigates several variables that may affect the potassium diffusion rate: viscous flow, oxygen diffusion, and water diffusion. The glass used in this experiment was HSQ300, a silica glass from Heraeus. The core of the glass cane was doped with ~1.2mol% potassium oxide. The cane underwent thermal cycling, then gradient index measurements were taken to trace the movement of potassium. Four thermal cycles were made on a glass-working lathe with a traversing set of hydrogen-oxygen burners that heated the cane for 31.5 minutes per cycle. The cane's surface was heated to 2256°C, and the equivalent temperature for diffusion in the core was calculated to be 1865°C. After four thermal cycles, the gradient index data showed a diffusion distance of 1.70mm. This resulted in a diffusion coefficient for potassium in silica D = (1.23 ± 0.54) x 10^-6 cm^2 /second. Further analysis indicated that potassium diffusion rate may have been influenced by water which diffused into the glass from the hydrogen-oxygen burner.
Synthesis of SiAlON Ceramics with Molecular Precursors as Additives
(New York State College of Ceramics at Alfred University. Inamori School of Engineering., 2022-05) McGarrity, Kade A.; Shulman, Holly; Misture, Scott; Wang, Kun; Ding, Junjun
Silicon nitride (Si3N4) and its related materials have been the subjects of research for 70 years and have garnered interest for applications ranging from cutting tools and bearings to turbine blades and spinal implants. The highly covalent nature of Si3N4 lends it exceptional structural properties such as high strength and hardness, but simultaneously renders it difficult to sinter. A few techniques are employed to ameliorate this challenge. The first is the generation of a solid solution of Al and O in the Si3N4 lattice, commonly through the use of Al2O3 powder, thereby reducing the covalency of the system and resulting in what is known as a SiAlON. The second is the incorporation of liquid phase sintering additives which enable a dissolution-reprecipitation sintering mechanism but which reside at the grain boundary after cooling as a relatively low-temperature glass. The present work investigates the incorporation of additives, including Al and O, via molecular-level precursors in order to tailor the sintering, microstructural evolution, and resultant structural properties of SiAlON ceramics. The first portion of this work demonstrates the incorporation of Al and O atoms with a very fine-scale homogeneous distribution via organometallic precursor aluminum tri sec-butoxide (ASB). A combination of chemical mapping, X-ray diffraction, thermogravimetric analysis, and differential thermal analysis was employed to investigate the pyrolytic decomposition of the organometallic precursor. Rietveld refinements were performed to assess the effectiveness of solid solution formation via the molecular precursor route to SiAlONs, in direct comparison to conventional Al2O3 powder-derived SiAlONs. Homogeneous distribution of Al which persists to at least 1000°C was achieved by the deposition of the organometallic precursor on starting Si3N4 powder surfaces, with no evidence of Al2O3 particle formation. Lattice refinements revealed that for various liquid phase concentrations and dwell times, the Al-organometallic more effectively facilitated the SiAlON solid solution than did Al2O3 powder. The second portion of this work investigates the incorporation of boron into the SiAlON system via precursor boric acid (H3BO3). Inspired by ultrahigh temperature polymer-derived ceramic SiBCN, this body of work aims to assess the roles of boron in a powder-route silicon-based ceramic system in the context of bonding, structural development, and ultimate structural properties. It was found through Raman spectroscopy and 11B SS MAS-NMR that boron exists in threefold coordination with nitrogen in the turbostratic boron nitride (t-BN) structure, similarly to in SiBCN. Increasing boron concentration in resultant SiAlONs results in a decrease in the population of both residual α-Si3N4 and second phases in the grain boundary, until a single phase β'-SiAlON was obtained at 3 wt% H3BO3. The grain size distributions of resultant SiAlONs were significantly narrowed by incorporating boron. Ultimately, fracture strength was increased from ~850 MPa to >1000 MPa by incorporating 3 wt% H3BO3. Subsequent in-depth fractographic analysis indicated that fracture origins of low-boron SiAlONs were predominantly inclusions consisting of either native material or foreign material from processing. However, boron-rich SiAlONs tended to fail from more elusive, less severe surface flaws such as machining cracks. It is proposed that the incorporation of boron reduces grain boundary diffusivity, mitigating abnormal grain growth or crystallization of second phases, effectively eliminating the worst flaw population in the present SiAlONs.
Development of Tests to Simulate Use Conditions and Fabrication of Additively Manufactured Ceramic Nozzles
(New York State College of Ceramics at Alfred University. Inamori School of Engineering., 2022-04) Mahany, Timothy R.; Shulman, Holly; Sundaram, S.K.; Ding, Junjun
Additive manufacturing (AM) allows for the rapid production of a desired shape, and enables the ability to modify the design before it is produced again. This can be a valuable tool in industry as a method for manufacturing prototypes, and larger runs of the same part, to an extent. There is a cost/benefit tipping point that is influenced by the complexity of the part, number of parts needed, frequency and value of design modifications, quality of parts produced, turnaround time, skill level of labor, infrastructure, profit margin for product, and other factors. AM of ceramics has lagged behind polymers and metals, as ceramic fabrication includes issues of shrinkage, distortion, and strength limiting process flaws. This AM alumina work was stimulated by a need in aerospace applications for a ceramic nozzle to replace a machined high temperature precious metal. This nozzles is an excellent test case for the rapid response of AM to develop a high value ceramic part. Technical ceramics can have superior characteristics, such as the ability to withstand high temperatures and high compressive forces, compared to other materials. Lithography-based Ceramic Manufacturing (LCM) is one of the current techniques that can be used for AM of ceramics. This work focused on producing nozzles out of Al2O3by means of LCM, and then subjecting the printed parts to internal pressure and thermal shock tests. To conduct pressure tests on the samples a custom apparatus had to be designed and produced to hold the sample while allowing the freedom to select the pressure that was applied. The testing jig was electronically controlled and allowed for a max pressure of 6.9 MPa (1,000 psi) to be tested. The printed Al2O3 parts were thermally shocked once to four different ΔT's; 300°C, 500°C, 700°C, 900°C. Each ΔT were then rapidly internally pressurized up to 205 times to two different pressures; 3.4 MPa (500psi), 6.9 MPa (1,000 psi). The ΔT's of 300°C and 500°C showed they could survive being thermally shocked and survive 6.9 MPa (1,000 psi). Whereas samples that had a ΔT of 700°C and 900°C received critical damage from being thermally shocked and could not handle any pressure.
Charge Storage in Defect Engineered Oxide Nanosheets
(New York State College of Ceramics at Alfred University. Inamori School of Engineering., 2022-02) Flint, Madeleine N.; Misture, Scott; Pilgrim, Steven; Tidrow, Steven; Shulman, Holly
Layered δ-MnO2 (birnessite) exhibits a unique response to the reduction of Mn4+ to Mn3+, where the reduced Mn3+ Jahn-Teller distorted octahedron creates a 'surface Frenkel defect.' The reduced Mn3+O6 octahedron migrates out of the the plane of the sheet and creates a vacancy within the sheet. The charged defect content may be controlled during flocculation of exfoliated nanosheets by equilibrating the nanosheet suspension in a pH regulated environment. It has been shown earlier that charged defects in δ-MnO2 improve electrochemical properties by increasing capacitance beyond 300 F/g, decreasing charge transfer resistance by a factor of 10, and improving life cycle stability. Building on earlier work, the present study aims to understand the synthesis of layered MnO2 and Mn-containing layered perovskites and their chemomechanical response during charge and discharge. X-ray total scattering, X-ray absorption spectroscopy, and Raman spectroscopy were employed to probe the chemomechanical response during electrochemical cycling of MnO2 electrodes in a custom-built electrochemical cell. While surface Frenkel defect content remained constant throughout electrochemical cycling, reversible reduction of Mn4+ to Mn3+ occurred, presumably within the sheet. MnO2 floccules equilibrated at a pH of 2 and 4 underwent 17% and 13% reduction from Mn4+ to Mn3+ upon K+ intercalation, respectively. Such reductions caused mechanical deformation of porous MnO2 electrodes and was found to be dependent on defect content and degree of restacking of the nanosheets. Floccules with a low degree of nanosheet restacking experienced lateral expansion upon K+ insertion of 0.7% and 0.5% for equilibration at a pH of 2 and 4, respectively, with no change in the interlayer (basal) direction spacing. However, MnO2 nanosheet floccules with a high degree of restacking experienced a 1.1% and 1.2% lateral expansion upon charging and a contraction in their basal direction of 1.7% and 0.7% for pH 2 and 4 samples, respectively. The interlayer contraction has been noted earlier, but largely eliminating the sheet-to-sheet stacking provides direct access to knowledge of the in-sheet chemomechanical response. Microstructures of air-dried and freeze-dried floccules as well as floccules with varying degrees of surface Frenkel defect content were similar. Surface Frenkel defect content remained constant across processing variations such as drying conditions and degree of restacking when equilibrated to the same pH.
Adhesion Studies with Ultra-Thin Glass
(New York State College of Ceramics at Alfred University. Inamori School of Engineering., 2022-02) Fekety, Curtis; LaCourse, William; Sundaram, S.K.; Clare, Alexis
A phenomenon was observed during work producing "ultra-thin glass" (<150μ thickness) where samples folded onto themselves displayed strong adhesion and served as a simple method to analyze contaminants in the process and packaging of resulting ware. Subsequent Contact Angle, Wedge Test, and T-Peel studies were performed to understand the baseline of Surface Free Energy (SFE) for this direct bonding and attempts were made to refresh aged and packaged samples through various cleaning steps to produce a similar effect. When results showed SFE change was minimal between aged, cleaned, and fresh glass and no treatments enabled similar direct bonding to fresh samples, 90° and 180° Peel Test with adhesive tapes and films were used as a surrogate to rank the effectiveness of attempted cleaning procedures. Such tests yielded widely ranging values inherent to known issues with peel testing, but provided useful data to calculate true adhesion values of just 2 - 2.5 N/m, which were 1 to 3 orders of magnitude less than the experimental values due to work absorbed by elastic/plastic effects when peeling the polymer adherend. Highly flexible glass samples do not experience plastic deformation, so studying direct bonded ultra-thin glass provides a unique perspective on adhesion studies by excluding plastic effects. It was also demonstrated that although the direct bonded samples had even lower peel strengths after initial separation, the bond strength was higher than strong tapes and even epoxy prior to edge-crack formation, showing the usefulness of direct bonding in optical materials and potential for future development.

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