A large portion of an airport property is occupied by runways and taxiways, which must be kept in excellent condition to ensure the safety of the airplanes, and the people on board. Any free objects on the airfield can cause damage to aircraft and are a possible danger to both the airplanes and the passengers. However, deterioration of the concrete airfield can be a major hazard and the presence of de-icing and anti-icing fluids may accelerate degradation. The focus of this project was the evaluation and assessment of aircraft de-icing and anti-icing fluids on the deterioration of airfield concrete. These fluids are used to remove and prevent snow and ice formation on aircraft by lowering the freezing temperature of water. The primary component in both fluids is ethylene glycol, while additives, which are proprietary and unknown, are mixed in to control various properties. Very little research has been done regarding the effect of the de-icer and anti-icers on the concrete deterioration. The aim of this study was to gain a better understanding of its influence on the deterioration of airfield concrete through a series of mechanical and electro-chemical tests, as well as microscopic and elemental analysis. Based on the comparative experiments and analyses performed using water, ethylene glycol, de-icer, and anti-icer, it appears that de-icing fluids do not prematurely cause concrete deterioration. In addition, experimental procedures in this study utilized the de-icing fluids as a concentrate, which are unrealistic conditions on an airfield, where dilution occurs from the addition of water and the presence of snow and ice. There was precipitate formation in all cases of cement paste exposure to de-icing fluid, however, which indicates that reactions are occurring and should be investigated further to determine the long term effects on concrete. With respect to the scope of this study, it was determined that the use of de-icers and anti-icers cause no significant detrimental effects on concrete mechanical properties and durability.

A large portion of an airport property is occupied by runways and taxiways, which must be kept in excellent condition to ensure the safety of the airplanes, and the people on board. Any free objects on the airfield can cause damage to aircraft and are a possible danger to both the airplanes and the passengers. However, deterioration of the concrete airfield can be a major hazard and the presence of de-icing and anti-icing fluids may accelerate degradation. The focus of this project was the evaluation and assessment of aircraft de-icing and anti-icing fluids on the deterioration of airfield concrete. These fluids are used to remove and prevent snow and ice formation on aircraft by lowering the freezing temperature of water. The primary component in both fluids is ethylene glycol, while additives, which are proprietary and unknown, are mixed in to control various properties. Very little research has been done regarding the effect of the de-icer and anti-icers on the concrete deterioration. The aim of this study was to gain a better understanding of its influence on the deterioration of airfield concrete through a series of mechanical and electro-chemical tests, as well as microscopic and elemental analysis. Based on the comparative experiments and analyses performed using water, ethylene glycol, de-icer, and anti-icer, it appears that de-icing fluids do not prematurely cause concrete deterioration. In addition, experimental procedures in this study utilized the de-icing fluids as a concentrate, which are unrealistic conditions on an airfield, where dilution occurs from the addition of water and the presence of snow and ice. There was precipitate formation in all cases of cement paste exposure to de-icing fluid, however, which indicates that reactions are occurring and should be investigated further to determine the long term effects on concrete. With respect to the scope of this study, it was determined that the use of de-icers and anti-icers cause no significant detrimental effects on concrete mechanical properties and durability.

The goal of this work is to provide a detailed description of the freezing mechanism in gold clusters. This is accomplished by using constrained Monte Carlo simulations combined with parallel tempering algorithms to evaluate the free energy barriers for various temperatures with respect to crystalline order parameters on a 456 atom cluster. <p>Our simulation results help us to challenge the usual assumption of classic nucleation theory where nucleation starts at the center of a cluster, showing instead that nucleation is favored by freezing started at the surface. We study simplistic phenomenological models for surface freezing and find that the three phase contact line free energy term must be included in order to properly describe the features of the free energy barriers. <p>Furthermore, we propose an alternative free energy parameter with which we are able to identify a kinetic spinodal temperature where the nucleation barrier disappears and find that the critical cluster size remains finite at the limit of stability of the fluid phase. This result is supported by Molecular Dynamics simulations.

Currently, the effect of the vertical resolution on the brightness temperature (BT) has not been examined in depth. The uncertainty of the freezing level (FL) retrieved using two different satellites' data is large. Various radiative transfer (RT) codes yield different BTs in strong scattering conditions. The purposes of this research were: 1) to understand the uncertainty of the BT contributed by the vertical resolution numerically and analytically; 2) to reduce the uncertainty of the FL retrieval using new thermodynamic observations; and 3) to investigate the characteristics of four different RT codes. Firstly, a plane-parallel RT Model (RTM) of n layers in light rainfall was used for the analytical and computational derivation of the vertical resolution effect on the BT. Secondly, a new temperature profile based on observations was absorbed in the Texas A&M University (TAMU) algorithm. The Precipitation Radar (PR) and Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) data were utilized for the improved FL retrieval. Thirdly, the TAMU, Eddington approximation (EDD), Discrete Ordinate, and backward Monte Carlo codes were compared under various view angles, rain rates, FLs, frequencies, and surface properties. The uncertainty of the BT decreased as the number of layers increased. The uncertainty was due to the optical thickness rather than due to relative humidity, pressure distribution, water vapor, and temperature profile. The mean TMI FL showed a good agreement with mean bright band height. A new temperature profile reduced the uncertainty of the TMI FL by about 10%. The differences of the BTs among the four different RT codes were within 1 K at the current sensor view angle over the entire dynamic rain rate range of 10-37 GHz. The differences between the TAMU and EDD solutions were less than 0.5 K for the specular surface. In conclusion, this research suggested the vertical resolution should be considered as a parameter in the forward model. A new temperature profile improved the TMI FL in the tropics, but the uncertainty still exists with low FL. Generally, the four RT codes agreed with each other, except at nadir, near limb or in heavy rainfall. The TAMU and the EDD codes had better agreement than other RT codes.

This study determined the effects of sucrose and sorbitol as cryoprotectant (CR) on the quality and sensory attributes of bone-in hams (N=90) injected (20% of weight) with following brine treatments (BT): control (2% sucrose; CNT), 2% CR (1% sucrose, 1% sorbitol), 4% CR (2% sucrose, 2% sorbitol). Hams that were frozen and injected with CNT after thawing (FZ I) were used as a negative control. After reaching the designated ST all bone-in hams were thawed under refrigeration (4oC) and FZ I hams were then injected with CNT (n=8). Hams were cooked to 70oC, chilled (7oC), sliced, vacuum packaged and analyzed for lipid oxidation, color, protein solubility and purge at 0, 28, and 56 of refrigerated storage while sensory evaluation and shear force determinations were conducted at 28 d. Color, pH, and lipid oxidation values tended to remain similar or decrease as frozen storage time increased. Water holding capacity (percent bound water) and protein solubility increased as frozen storage increased. The 4% CR BT exhibited the lowest shear force value (4.04 N/g) but was not statistically different than CNT or FZ I on ham knuckle muscles. Trained sensory panelists found hammy and salty were the strongest flavor and basic taste attributes. The results of this study confirm that quality attributes and protein functionality were maintained but not significantly improved by injecting a brine solution with cryoprotectants prior to freezing.

Attention has begun to focus on the pulmonary delivery of antifungal agents for invasive fungal infections as inhalation of the fungal spores is often the initial step in the pathogenesis of many of these infections. Invasive fungal infection in the lungs in immunocompromised patients has high mortality rates despite current systemic (oral or intravenous) therapies. However, drug delivery of antifungal agents directly to the lungs could potentially result in high concentrations of drug in the lungs, a quicker onset of action, and reduction of systemic side effects. Voriconazole (VRC) is a second, generation triazole antifungal agent with increased potency, a broad spectrum of antifungal activity, and a fairly poor aqueous solubility. It is the recommended therapeutic agent for the treatment of Invasive Pulmonary Aspergillosis (IPA), and its use has improved therapeutic outcomes in immunocompromised patients with IPA. Still, systemic administration by oral or intravenous delivery is limited by high inter- and intra-patient pharmacokinetic variability, many potential drug interactions, and a narrow therapeutic index with many adverse effects, leading to clinical failures. Therefore, development of novel particulate formulations containing VRC for targeted drug delivery to the lungs is critical to improving therapeutic outcomes in patients with invasive fungal infections in the lungs. Within the framework of this dissertation, two particle engineering processes, thin film freezing (TFF) and advanced evaporative precipitation into aqueous solution (AEPAS), were investigated. The goal was to investigate microcrystalline VRC, nanocrystalline VRC, and nanostructured amorphous VRC formulations suitable for pulmonary delivery and to determine the effect of morphology on the in vivo deposition and distribution of inhaled particulate VRC formulations. TFF process parameters significantly affected the solid state properties and aerodynamic performance of the dry powder formulations containing VRC. Following dry powder insufflation into the lungs of mice, microstructured crystalline TFF-VRC achieved higher and more prolonged concentrations of VRC in the lungs with slightly lower systemic bioavailability than nanostructured amorphous TFF-VRC-PVP K25. AEPAS and TFF of template nanoemulsions did not lead to production of crystalline nanoparticles, as predicted. In particular, VRC proved to be a difficult molecule to stabilize in the nanocrystalline and nanostructured amorphous states. Ultimately, this body of work demonstrated that the particle engineering process, TFF, could be used to develop voriconazole formulations suitable for dry powder inhalation with more favorable pharmacokinetic parameters compared to inhaled voriconazole solution. / text

Critical to a cell's survival is its ability to deal with stress by making an appropriate response. This response often takes place in the cytoplasm, which is everything contained within the cell's plasma membrane that is not the nucleus. The cytoplasm is a dynamic environment and its ability to reorganize is essential to the cell's function. This dissertation presents a novel, previously undiscovered state of cytoplasm organization for the model system Schizosaccharomyces pombe, also known as fission yeast. Typically the fission yeast cytoplasm is a fluid-like environment in which endogenous lipid granules subject to thermal fluctuations, move freely as they explore their local surroundings through diffusion. When the cell is in a nutrient depleted environment it is exposed to the stress of advanced glucose starvation. As a result, we find that the cytoplasm undergoes drastic reorganization reminiscent of a phase transition; it is now a solid-like environment in which there is no visible motion. Lipid granules throughout the cell appear to be completely immobilized and are unable to move through the cytoplasm, despite the application of force through optical tweezers. We term this cytoplasmic state the cell frozen state. The cell frozen state is a physiological state, one that the cell can recover from with the addition of fresh nutrients. It is characterized by an anomalous diffusion exponent of [alpha] = 0.23 ± 0.01, which is a significant reduction from the anomalous diffusion exponent [alpha] = 0.66 ± 0.01 found for exponentially growing cells in which there is visible motion. To account for the cell wide immobilization of lipid granules, we hypothesize the formation of a polymer network all through the cytoplasm, and identify septins 1-3 as the most likely filament formers. In addition, we find there is an increase in the number of vacuoles in the cytoplasm during starvation, and propose a vacuole-septin model to describe the cytoplasm reorganization for the cell frozen state. / text

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Current design guidelines for reinforced soil walls and slopes recommend the use of granular soils such as gravels and sands as select fills. Cost savings could potentially be realized by using on-site clays and silts. Some clays are swelling and silts are frost susceptible. When considering the use of swelling clays and frost susceptible silts as fills, environmental loading due to swelling-shrinkage and freeze-thaw effects from environmental changes could become a design issue. To examine the hypothesis that consideration of environmental loading during design will produce improvements in the performance of geosynthetic-reinforced soil structures that use clays or silts as fill materials, experimental and numerical studies were undertaken. Geosynthetic-reinforced clay specimens were subjected to wetting and drying in a model test apparatus developed and commissioned for this study. In separate test set-up, reinforced silt specimens were subjected to freezing and thawing. Tests on unreinforced specimens were also performed in otherwise identical conditions for comparison purposes. Movements of the specimens, soil strains, reinforcement strains, soil suctions and soil temperatures were monitored during the application of environmental loading in addition to mechanical loading from external stresses. The results of the laboratory model tests showed that reinforcements reduced horizontal displacements of the clay specimens during wetting and drying. The same is true for the case of silt during freezing and thawing. The environmental loading induced strains, and therefore stresses in the reinforcements. The measured geogrid strain during the wetting-drying of reinforced clay specimen was up to 0.75%. Similarly, the measured geogrid strain in the reinforced silt specimen during freezing-thawing cycles was up to 0.57%. The strains were greater than the strains generated by mechanical loading for the range of applied stresses used in this study. Numerical models were developed to simulate wetting only induced swelling of reinforced clays and freezing only induced expansion of reinforced silts specimens. They were used to simulate the results of laboratory model tests. The performance of geosynthetic-reinforced soil slopes with swelling clay fills and frost susceptible silt fills was evaluated. Parametric studies were performed to determine important parameters affecting the performance of reinforced clay and silt slopes.