Doctor of Philosophy

dissertationStudies on the evolution of soot particle size distributions during the process of soot oxidation were carried out in the two-stage burner by using a Scanning Mobility Particle Sizer (SMPS) for n-butanol/n-dodecane, methyl decanoate/n-dodecane, and ethylene flames. This experimental technique, along with measurements of flame temperature, gas-phase composition, surface functional groups, and soot nanostructure and morphology, allowed for identifying effective parameters during soot oxidation and the mechanisms associated with soot oxidation-induced fragmentation. The results of increasing n-butanol and methyl decanoate in n-dodecane showed a reduced sooting propensity; however, it did not enhance soot oxidative reactivities. The result of image analysis technique demonstrated a strong dependence of soot oxidation rate on the initial soot nanostructure, whereas oxygen functionalities did not matter as much. The highest soot oxidative reactivity was found for the soot nanostructure with the minimum degree of orderliness. On the other hand, the lowest oxidative reactivity was observed for the soot with the nanostructure composed of large layer planes with either low or zero curvatures. Soot oxidation-induced fragmentation was studied by using ethylene fuel. The mechanisms of soot oxidation-induced fragmentation were explored by following changes in mobility size, number and concentration, flame temperature, and gas-phase compositions. Results showed that the rate of fragmentation was inversely proportional to the peak temperature, and the onset of fragmentation depended on the presence of aggregates. In addition, two main mechanisms suggested in the literature, (i) aggregate break-up by burning bridges; (ii) primary particle break-up by O2 diffusion, were tested with the aid of an image analysis technique. The results demonstrated that bridge sites were formed by less-ordered nanostructure, resulting in a faster burning rate, suggesting aggregate fragmentation by this mechanism. The effectiveness factor calculation was used to evaluate the feasibility of primary particle breakup by O2 internal burning. It was shown the primary particle breakup for particles smaller than 10 nm becomes more probable by decreasing temperature and increasing O2 partial pressure

Engineering A Retinal Progenitor Cell Graft For Transplantation Studies In The Rd10 Mouse Model

In later stages of retinal degenerative diseases such as age-related macular degeneration (AMD) and retinitis pigmentosa stem cell therapy can be the only viable treatment option due to the loss of photoreceptor and RPE cells. Differentiation of embryonic stem cells (ESCs) towards the desired lineage explicitly requires a microenvironment that mimics the natural tissue that it is intended to regenerate. Developing a planar 3D retinal graft derived from ESCs can be transplanted to treat various retinal degeneration diseases. Our aim was to explore the differentiation and growth of ESCs on a gelatinous scaffold in order to transplant into a retinitis pigmentosa mouse model (RD10). Our aim was to evaluate the transplanted graft for host inflammatory response, stem cell integration, cell survival, and tumorigenesis. The transplanted graft was also compared to injection of a homogenous photoreceptor cell population into the subretinal space of the RD10 mouse model. A biocompatible gelatinous scaffold was developed in order to support the differentiation of a multilayered retinal structure. ESCs were seeded onto the scaffold for proliferation and differentiation in the vicinity of retinal pigment epithelium cells. Cultures were analyzed for differentiation by qRT-PCR and immunofluorescence confocal microscopy. The graft was transplanted into the subretinal space to examine biocompatibility and retinal progenitor cell integration into the native mouse retina. ESCs migrated through the 60μm thickness of the scaffold and differentiated into the retinal progenitor cells as evidenced by qRT-PCR and immunohistochesmistry. In-vivo testing analyzed on 1st, 3rd and 6th week showed scaffold degradation by the 6th week. The gelatinous scaffold supported the differentiation of ESCs to RPCs and minimal inflammatory response was seen post transplantation

The development of pictorial tools for obstructive sleep apnoea syndrome

Introduction: Obstructive sleep apnoea syndrome (OSAS) is common but remains underdiagnosed and is linked with several disease states and increased risk of mortality. The key symptom, excessive daytime sleepiness, is commonly measured with the Epworth Sleepiness Scale which is not always easily completed by patients. The aim of this thesis is to develop pictorial material for assessing sleepiness and risk of OSAS. Methods: Health literacy was measured in a sample sleep population and the Epworth Sleepiness Scale was investigated for ease of use. Images were developed to translate the Epworth into pictures and the response to pictures of ‘driving while sleepy’ was investigated in detail. A new tool, the pictorial Sleepiness and Sleep Apnoea Scale, was devised by adding four sleepiness images from the pictorial Epworth to four new images representing ‘risk of OSAS’. Evaluations were made in two populations of the tool’s potential in predicting those at risk of OSAS. Results: Poor or impaired health literacy was found in 16% of patients attending the sleep clinic. Evaluation of the Epworth Sleepiness Scale found that a third of new patients made quantifiable errors. A preference for the pictorial Epworth Sleepiness Scale was reported by 55% of users and a kappa statistic indicated good agreement between the pictorial and traditional Epworth Sleepiness Scale. Drivers were more inclined to record feeling sleepy if the image in Q8 depicted the sleepy person in the car as a passenger. In a sleep clinic population the pictorial Sleepiness and Sleep Apnoea Scale was slightly better at predicting disease than the Epworth. In a cardiac rehabilitation clinic use of the witnessed apnoea image from the pictorial Sleepiness and Sleep Apnoea Scale, along with the Epworth Sleepiness Scale, helped to identify symptoms suggestive of sleep apnoea in a third of those screened. When investigated with a sleep study, the prevalence of sleep–disordered breathing in this patient group was 14.8%. Conclusion: Pictorial tools for patients with potential obstructive sleep apnoea syndrome have clinical value and can help bridge the gap between poor or impaired health literacy and the material we use to assess sleepiness and likelihood of obstructive sleep apnoea syndrome.Open Acces

Mechanics and durability of lime-based textile reinforced mortars

Application of lime-based textile-reinforced mortars (TRMs) for strengthening of masonry structures have received a growing attention in recent years. An extensive effort has been devoted to understanding of the performance of these composites and their effectiveness in improving the seismic safety of existing masonry structures. Nevertheless, several aspects regarding the durability and mechanics of these composites still remain unknown. This letter is an effort on highlighting those aspects considering both experimental and numerical modelling approaches

Detection and localization of debonding damage in composite-masonry strengthening systems with the acoustic emission technique

Different types of strengthening systems, based on fiber reinforced materials, are under investigation for external strengthening of historical masonry structures. A full characterization of the bond behavior and of the short—and long-term failure mechanisms is crucial to ensure effective design, compatibility and durability of the strengthening solution. In this paper, the effectiveness of the Acoustic Emission (AE) technique for debonding characterization and localization on Fiber Reinforced Polymer (FRP)- and Steel Reinforced Grout (SRG)-strengthened clay bricks is investigated. The AE technique proofs to be efficient for damage detection during accelerated ageing tests under thermal cycles and during experimental shear bond tests. AE data demonstrated the thermal incompatibility between brick and epoxy-bonded FRP composites during the accelerated ageing tests and debonding damage was successfully detected, characterized and located during the shear bond tests.- (undefined

From text to tech: Shaping the future of physics-based simulations with AI-driven generative models

This micro-article introduces a method for integrating Large Language Models with geometry/mesh generation software and multiphysics solvers, aimed at streamlining physics-based simulations. Users provide simulation descriptions in natural language, which the language model processes for geometry/mesh generation and physical model definition. Initial results demonstrate the feasibility of this approach, suggesting a future where non-experts can conduct advanced multiphysics simulations by simply describing their needs in natural language, while the code autonomously handles complex tasks like geometry building, meshing, and setting boundary conditions

Session 1-2-E: The Indirect Contribution of Non-gaming Amenities to Casino Gaming Performance

Objective Evaluate the simultaneous impact of all non-gaming amenities on gaming volum