Engineering Commons^™

Progress Toward Durable Icephobic Materials, Matthew J. Coady

Electronic Thesis and Dissertation Repository

Ice accumulation is a major engineering challenge in many fields including aerospace, power generation, transportation, and infrastructure. A variety of solutions are being researched to address this challenge. Perhaps the most promising method of combating ice accumulation is by applying coatings with low values of interfacial ice adhesion strength, τ_ice. Icephobic materials are those with ice adhesion below 100 kPa, and it has been shown that passive delamination can occur on surfaces with τ_ice below 20 kPa. While various low adhesion surfaces have been prepared, durability concerns pervade applications where surfaces experience repeated icing or freeze-thaw cycles, …

Application-Specific Oxide-Based And Metal-Dielectric Thin Film Materials Prepared By Rf Magnetron Sputtering Preprints201908.0184.V1.Pdf, Mohammad Nur-E-Alam, Wade Lonsdale, Mikhail Vasiliev, Kamal Alameh

Mikhail Vasiliev

Collagen-Mimetic Hydrogels Promote Human Endothelial Cell Adhesion, Migration And Phenotypic Maturation, Dany J. Munoz Pinto, V. R. Guiza-Arguello, S. M. Becerra-Bayona, J. Erndt-Marino, S. Samavedi, S. Malmut, B. Russell, M. Höök, M. S. Hahn

Dany J. Munoz Pinto

This work evaluates the response of human aortic endothelial cells (HAECs) to thromboresistant collagen-mimetic hydrogel coatings toward improving the biocompatibility of existing "off-the-shelf" small-caliber vascular grafts. Specifically, bioactive hydrogels-previously shown to support α1/α2 integrin-mediated cell adhesion but to resist platelet activation-were fabricated by combining poly(ethylene glycol) (PEG) with a 120 kDa, triple-helical collagen-mimetic protein (Scl2-2) containing the GFPGER adhesion sequence. Analysis of HAECs seeded onto the resulting PEG-Scl2-2 hydrogels demonstrated that HAEC adhesion increased with increasing Scl2-2 concentration, while HAEC migration rate decreased over this same concentration range. In addition, evaluation of HAEC phenotype at confluence indicated significant differences in …

Design Of Tissue-Specific Cellular Microenvironments For Adipose-Derived Stromal Cell Culture And Delivery, Arthi Shridhar

Electronic Thesis and Dissertation Repository

The development of in vitro cell culture models that investigate tissue-specific effects of the extracellular matrix (ECM) on stem/progenitor cell lineage-commitment can contribute towards the design of improved cell delivery strategies. This thesis developed processing methods that conserved ECM bioactivity to generate well-characterized 2- and 3-D culture platforms that facilitated the evaluation of ECM composition on the adipogenic and osteogenic differentiation of human adipose-derived stromal cells (ASCs). Initial work compared α-amylase and pepsin digestion as methods to fabricate ECM coatings. The effects of enzyme processing and ECM composition were explored using human decellularized adipose tissue (DAT) and bovine tendon collagen …

Coatings On Mammalian Cells: Interfacing Cells With Their Environment, Kara A. Davis, Pei-Jung Wu, Calvin F. Cahall, Cong Li, Anuhya Gottipati, Brad J. Berron

Chemical and Materials Engineering Faculty Publications

The research community is intent on harnessing increasingly complex biological building blocks. At present, cells represent a highly functional component for integration into higher order systems. In this review, we discuss the current application space for cellular coating technologies and emphasize the relationship between the target application and coating design. We also discuss how the cell and the coating interact in common analytical techniques, and where caution must be exercised in the interpretation of results. Finally, we look ahead at emerging application areas that are ideal for innovation in cellular coatings. In all, cellular coatings leverage the machinery unique to …

Protection Of High-Voltage Transformer Bushings And Other Brittle Structures Against Impact, Christine Nichole Henderson

Electronic Theses and Dissertations

This dissertation contributes unique approaches to improve the fundamental understanding of the impact behavior of porcelain high-voltage (HV) transformer bushings under high-velocity impact, with a focus on their protection with feasible methods which could be quickly applied in service to prevent vandalism and other undesirable impact situations. The bushings are brittle and pressurized; prone to explosive damage when hit by a high-velocity projectile. Damaged bushings can destroy transformers and entire substations in complex fashions. This can put the power grid at risk for cascading failures and electrical blackouts, affecting consumers. Therefore, suggesting practical approaches which could be used to protect …

Application-Specific Oxide-Based And Metal-Dielectric Thin-Film Materials Prepared By Radio Frequency Magnetron Sputtering, Mohammad Nur-E-Alam, Wade Lonsdale, Mikhail Vasiliev, Kamal Alameh

Research outputs 2014 to 2021

We report on the development of several different thin-film functional material systems prepared by radio frequency (RF) magnetron sputtering at Edith Cowan University nanofabrication labs. While focusing on the RF sputtering process optimizations for new or the previously underexplored material compositions and multilayer structures, we disclose several unforeseen material properties and behaviours. Among these are an unconventional magnetic hysteresis loop with an intermediate saturation state observed in garnet trilayers, and an ultrasensitive magnetic switching behaviour in garnet-oxide composites (GOC). We also report on the unusually high thermal exposure stability observed in some nanoengineered metal-dielectric multilayers. We communicate research results related …

The Effect Of Curing And Zirconium Content On The Wettability And Structure Of A Silicate Hybrid Sol-Gel Material, Emma Machugh, Maikki Cullen, Alicja Kaworek, Brendan Duffy, Mohamed Oubaha

Articles

Functional hybrid sol-gel coatings have been developed for numerous applications with a wide range of wettabilities. This study proposes to investigate the relationship between the structure and the wetting properties of a zirconium modified silicate hybrid sol-gel coating. The structures of the coatings were altered by varying the content of zirconium, and the curing process, while keeping the sol-gel preparation conditions identical. The structure of the materials was characterized by FTIR, 29Si NMR and SEM. The thermal properties and the wettability are identified by DSC and contact angle measurements, respectively. By corroborating the structural and wettability analyses, it is shown …

Phase Separation And Enhanced Wear Resistance Of Cu88fe12 Immiscible Coating Prepared By Laser Cladding, Shuzhen Zhao, Shengfeng Zhou, Min Xie, Xiaoqin Dai, Dongchu Chen, Laichang Zhang

Research outputs 2014 to 2021

In order to eliminate the microstructure segregation of Cu–Fe immiscible alloys which characterized with a liquid miscible gap, the Cu88Fe12 (wt.%) immiscible coating was prepared by laser cladding. The phase separation characteristic and wear resistance of the Cu88Fe12 (wt.%) immiscible coating were also investigated. The results show that the size of the milled Cu88Fe12 composite powder is reduced comparing to that of the un-milled powder due to fracturing during mechanical milling. Moreover, the demixing or delamination disappears in the Cu88Fe12 immiscible coating and a large amount of face-centered-cubic (fcc) γ-Fe and body-centered-cubic (bcc) α-Fe particles are dispersed in the face-centered-cubic …