The use of water based adhesive primers in enhancing the durability of aluminum adhesively bonded with epoxy was studied. The effects of the thickness of both the aluminum oxide surface layer and the primer layer on bond durability were established. 5052 aluminum alloy was oxidized by phosphoric acid anodization prior to primer coating. The oxide layer thickness was controlled mainly by changing anodization voltage and directly measured using a HR-SEM (high resolution scanning electron microscope). The oxide layer was also examined by AES (Auger electron spectroscopy) and XPS (X ray photoelectron spectroscopy). The surface oxide layer was porous and the thickness varied from 0.2 to 2.2 μm. The anodized aluminum substrates contained 3 atomic % of phosphorus and were coated with several solid concentrations of water based adhesive primers. These primers contained non-reactive polyurethane emulsions, and were dried at room temperature. The primer thicknesses were measured by ellipsometry. The primer penetrated into the aluminum oxide pores, confirmed by observing the primer surface after the aluminum oxide was removed by dissolving in dilute NaOH aqueous solution. All adhesive bonding was done using the wedge test configuration with a structural epoxy adhesive, Naviloc® XY 0210, which was cured for 30 min. at 180°C. The wedge samples were immersed in 80°C water and crack lengths were monitored as a function of time. Both the initial crack length and crack propagation were minimized when the primer thickness was a little less than the aluminum oxide thickness. In a separate study, the aluminum oxide surfaces were aged in hot water or hot humid environment before bonding. The crack lengths of the aged samples for both 60°C water immersion and 70°C ≥95 %R.H. conditions were similar to those of non-aged sample. On the other hand, when the samples were aged in 80°C water, the oxide was hydrated and the crack length increased. The locus of failure also changed from cohesive failure in the adhesive for the lower temperature aged samples to a mixed mode of cohesive failure and aluminum oxide-primer interfacial failure for the 80°C aged samples. / Master of Science

Creosote, containing many high molecular weight hydrophobic polycyclic aromatic hydrocarbons (PAH's), is present in the subsurface environment at the Oneida Tie-Yard in Oneida, Tennessee. Phytoremediation using hybrid poplar trees was chosen as the remedial technology on-site. Since monitoring began, the contaminant plume has been shrinking consistently and evidence has shown that remediation is taking place. However, remediation may be rate-limited by the desorption and dissolution kinetics of the PAH's on-site. The objectives of this research are to: (1) estimate the desorption and dissolution rates of 10 PAH's found in the subsurface and (2) estimate the amount of each PAH and total mass of contaminant that is irreversibly sorbed to the soil. Three laboratory desorption and dissolution experiments were performed using contaminated soil samples from the Oneida Tie-Yard site. The first experiment was a batch desorption equilibrium experiment, the second was a batch desorption kinetics experiment, and the third was a soil column dissolution kinetics experiment. The target compounds in this study were: naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, chrysene, and benzo(b)fluoranthene. The resulting data for the desorption equilibrium experiment revealed that rates of equilibrium were truly not instantaneous in the systems studied. However, because approximately 76% of PAH's desorbed by the first sampling event (3 days), an equilibrium isotherm was considered appropriate. Results showed that there is a sorbed reversible concentration that readily desorbs to the aqueous phase for each PAH. Additionally, it was determined that the percent removal of sorbed PAH's decreases with increasing molecular weight. Desorption curves based on experimental data were found to exhibit linear behavior over large variations in aqueous concentration, but showed exponential behavior as concentrations approached zero. Freundlich sorption equilibrium isotherms for the 10 monitored PAH's on-site were generally found to have N coefficient values over 1, especially over large variations in solution phase concentration, indicating a non-uniform sorbent. Dissolution of resistant PAH's under field-like conditions was determined to occur over long periods of time. Dissolution rates calculated from experimental data were shown to generally decrease with increasing molecular weight. Overall, desorption and dissolution kinetics of PAH's were shown to be rate-limiting factors to remediation at the Oneida Tie-Yard. / Master of Science

Composite durability can be influenced by varying the properties of the fiber/matrix interphase region. One method to modifY the properties of this interphase is through the application of a sizing to the carbon fiber. Recent work at Virginia Tech has shown that polymer-modified interphases can lead to increases by as much as two orders of magnitude in notched fatigue lifetime. In the present work, an apparatus was constructed to uniformly coat carbon fiber tow with water-soluble and dispersible polymers. Few such devices have been developed for use in academic settings because of the processing complexities presented by the aqueous coating system. Due to the high surface tensions of the aqueous solutions, fiber clumping and heterogeneous sizing deposition were major bottlenecks. Our novel process utilizes high tensions, high spreading, and low line speeds to accomplish the sizing step. Each processing independent variable can be continuously monitored and controlled which allowed for statistical correlation to the sizing level and uniformity. The sizing process was shown to satisfy three criteria for quality. 1. The average sizing level or weight percent on the final fiber can be readily controlled to achieve typical target values. 2. Filament clumping as a result of cohesion between corresponding filaments is kept to a minimum. 3. The sizing process must produce fiber with a consistent level of polymer sizing. In addition, characterization techniques for the sized fiber were developed. Pyrolysis in a high temperature nitrogen furnace was developed as a precise technique to ascertain the quantitative sizing level on the carbon fiber. SEM and ESCA were utilized to determine fiber clumping and sizing homogeneity. The sizing process along with the statistical process model and the characterization techniques allow for the precise development of optimal interphase materials that are tailored to meet the performance requirements of the composite consumer. / Master of Science

Our research seeks new methods for functionalizing organic small molecules using organoboronic derivatives as a versatile handle for late-stage manipulations. Metal-catalyzed formation of new carbon-boron bonds and their subsequent transformations are highlighted. Among the myriad of unsaturated substrates for conducting borylation reactions, allenes have received minimal attention. These substrates are uniquely advantageous given that diboration results in the formation of both allylic and vinylic boronates. Orthogonal reactivity of the sp2 and the sp3 C-B bonds can allow for chemoselective transformations. However, oxidation of the carbon-boron bond is one example in which the conditions are unselective. To address this shortcoming, a platinum catalyst was developed for the diboration of 1,1-diaryl allenes with a differentially protected diboron reagent, pinB-Bdan. The reaction proceeds regioselectively in high yields to furnish olefins bearing a vinylic Bpin and an allylic Bdan moiety. The subsequent chemoselective transformation of each boron center was demonstrated. Methods for preparing 1,8-diaminonaphthalene protected vinylboronates conjugated to carbonyl groups are severely limited. A simple and efficient protocol was developed for carrying out an environmentally friendly copper(II)-catalyzed beta-borylation of alkynoates and alkynamides in water and open-to-air. Following the discriminative activation of the more Lewis acidic pinacol protected boron center in pinB-Bdan, a regio-, stereo- and chemoselective beta-borylation of acetylenic substrates delivers (Z)-beta-boryl enoates and primary, secondary, and tertiary enamides under very mild conditions. As an inexpensive and earth abundant metal, catalysts based on copper are highly desirable. An international collaborative project to develop a copper-catalyzed cross-coupling reaction of beta-boryl carbonyl compounds was explored. Preliminary results found these substrates to be either unstable towards or unreactive under the reactions conditions screened. / Ph. D.

Tobacco has long been considered as a host to produce large quantities of high-valued recombinant proteins. However, dealing with large quantities of biomass with a dilute concentration of product is a challenge for down-stream processing. Aqueous two-phase extraction (ATPE) has been used in purifying proteins from various sources. It is a protein-friendly process and can be scaled up easily. ATPE was studied for its applicability to recombinant protein purification from tobacco using egg white lysozyme as the model protein. Separate experiments with polyethyleneglycol(PEG)/salt/tobacco extract, and PEG/salt/lysozyme were carried out to determine the partition behavior of tobacco protein and lysozyme, respectively. Two level fractional factorial designs were used to study the effects of factors such as PEG molecular weight, PEG concentration, the concentration of phase forming salt, sodium chloride concentration, and pH on protein partitioning. The results showed that PEG/sodium sulfate system was most suitable for lysozyme purification. Detailed experiments were conducted by spiking lysozyme into the tobacco extract. The conditions with highest selectivity of lysozyme over native tobacco protein were determined using a response surface design. The purification factor was further improved by decreasing the phase ratio along the tie line corresponding to the phase compositions with the highest selectivity. Under selected conditions the lysozyme yield was predicted to be 87% with a purification factor of 4 and concentration factor of 14. The binodial curve and tie line corresponding to the optimal condition for lysozyme recovery for the PEG 3400/sodium sulfate system were developed. The selectivity at the optimal condition was experimentally determined to be 47 with a lysozyme yield of 79.6 % with a purification factor of 10 and a concentration factor of 20. From this study, ATPE was shown to be suitable for initial protein recovery and partial purification from transgenic tobacco. / Master of Science

京都大学 / 新制・課程博士 / 博士(工学) / 甲第25289号 / 工博第5248号 / 京都大学大学院工学研究科材料工学専攻 / (主査)教授 邑瀬 邦明, 教授 杉村 博之, 教授 宇田 哲也 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Yes / We investigate how the presence of Ca2+ ions at the aqueous TiO2 interface influences the binding modes two experimentally-identified titania-binding peptides, Ti-1 and Ti-2, using replica exchange with solute tempering molecular dynamics simulations. We compare our findings with available experimental data and contrast our results with those obtained under NaCl solution conditions. We find that for Ti-1, Ca2+ ions enhances the adsorption of the negatively-charged Asp8 residue in this sequence to the negatively-charged surface, via Asp{Ca2+{TiO2 bridging. This appears to generate a non-local impact on the adsorption of Lys12 in Ti-1, which then pins the peptide to the surface via direct surface contact. For Ti-2, fewer residues were predicted to adsorb directly to the surface in CaCl2, compared with predictions made for NaCl solution, possibly due to competition between the other peptide residues and Ca2+ ions to adsorb to the surface. This reduction in direct surface contact gives rise to a more extensive solvent-mediated contact Ti-2. In general, the presence of Ca2+ ions resulted in a loss of conformational diversity of the surface-adsorbed conformational ensembles of these peptides, compared to counterpart data predicted for NaCl solution. Our findings provide initial insights into how peptide{TiO2 interactions might be tuned at the molecular level via modification of the salt composition of the liquid medium. / Air Office of Scientific Research, grant number FA9550-12-1- 0226.

Master of Science / Department of Clinical Sciences / Amy J. Rankin / Objective – To measure blood aqueous-barrier breakdown following aqueocentesis using various needle sizes and to monitor the intraocular pressure (IOP) response. Animals – 24 healthy, adult dogs received treatment (24 treated eyes, 24 contralateral eyes); 3 dogs were untreated controls (6 control eyes). Procedures – Dogs receiving treatment were divided into 3 equal groups (25-, 27-, or 30- gauge needle aqueocentesis). In each dog the treated eye was determined randomly, the contralateral eye was untreated. Dogs that did not have aqueocentesis performed in either eye were used as controls. Aqueocentesis at the lateral limbus was performed under sedation and topical anesthesia. Anterior chamber fluorophotometry was performed before and after aqueocentesis on day 1. On days 2-5 sedation and fluorophotometry were repeated. Intraocular pressure was measured with a rebound tonometer at multiple time points. Results – Aqueocentesis resulted in blood-aqueous barrier breakdown in all treated eyes with barrier reestablishment present by day 5 detected by fluorophotometry. On day 2 the contralateral untreated eyes of all groups also showed statistically significant increased fluorescence (P < 0.05) following treatment of the opposite eye, but these values were not statistically significantly greater than untreated controls. In treated eyes there was no statistical difference in fluorescein concentration or IOP between 27- and 30-gauge needles. Use of the 25- gauge needle resulted in a statistically significant increase in anterior chamber fluorescence on days 3 and 5. It also caused a statistically significant increase in IOP 20 minutes following aqueocentesis as compared to the 27- and 30-gauge needles. Aside from this transient ocular hypertension, rapid resolution of ocular hypotony following aqueocentesis was observed in all treatment groups. Conclusions and Clinical Relevance – Aqueocentesis using a 25-gauge needle resulted in a greater degree of blood-aqueous barrier breakdown and a brief state of intraocular hypertension following paracentesis. Use of a 27- or 30-gauge needle is recommended for aqueous paracentesis. A consensual ocular reaction appeared to occur in dogs following unilateral traumatic blood-aqueous barrier breakdown and may be of clinical significance. Statistical significance was limited in this study due to high variability and large standard deviations.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23515号 / 工博第4927号 / 新制||工||1769(附属図書館) / 京都大学大学院工学研究科物質エネルギー化学専攻 / (主査)教授 安部 武志, 教授 陰山 洋, 教授 作花 哲夫 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

The thesis, which contains nine chapters, reports extensive large scale atomistic molecular dynamics (MD) simulation studies of water structure and dynamics at the surface of an anionic micelle, hydration layer of two proteins, and in the grooves of a 38-base pairs long DNA. Understanding the structure and dynamics of water molecules at the surfaces of self-organized assemblies and complex biological macromolecules has become a subject of intense research in recent times. Chapter 1 contains a brief overview of the biomolecular hydration dynamics. Relevant experimental, computational, and theoretical studies of biomolecular hydration and the time scales associated with the water dynamics are discussed. In Chapters 2 and 3, the structure, environment, energetics, and dynamics of constrained water molecules in the aqueous anionic micelle of cesium perfluorooctanoate (CsPFO) have been studied using large scale atomistic molecular dynamics simulations. Based on the number of hydrogen bond (HB) that interfacial water molecule makes with the polar head group (PHG) oxygen of the micelle, we find the existence of three kinds of water at the interface. We introduce a nomenclature to identify the species as IBW2 (form two HBs with two different PHG), IBW1 (form one HB with PHG), and IFW (no HB with PHG). Despite of possessing two strong w-PHG bonds, the concentration of the IBW2 species is rather low due to entropic effect. The ion solvation dynamics study at the interface shows the presence of a slow component, with a relaxation time 1-2 order of magnitude slower than that in the corresponding bulk solvent in agreement with the experimental results. Both the translational and orientational dynamics of the water molecules near the micellar surface is found to be much slower than those in the bulk. The HB between the PHG of the micelle and the water molecule has almost 13 times longer life time than that in the bulk between two tagged water molecules. In Chapter 4, we present results of extensive atomistic MD simulation studies of the structure and dynamics of aqueous protein solution of the toxic domain of Enterotoxin (1ETN) and the chicken villin headpiece sub-domain containing 36 amino acid residues (HP-36). Reduced water structure and the faster water dynamics around the active site of these proteins have been observed which may have biological significance. Chapter 5 presents an extensive atomistic molecular dynamics simulations study of water dynamics in the hydration layer of a 38 base long hydrated DNA duplex. The computed rotational time correlation function (TCF) of the minor groove water dipoles is found to be markedly non-exponential with a slow component at long time. The constrained water molecule is also found to exhibit anisotropic diffusion in both the major and minor grooves. At short-to-intermediate times, translational motion of water molecules in minor groove is sub-diffusive. Chapter 6 presents the study of water entropy in both the grooves DNA. The average values of the entropy of water at 300K in both the grooves of DNA are found to be significantly lower than that in bulk water. We propose that the configurational entropy of water in the grooves can be used as a measure of the mobility (or micro viscosity) of water molecules in a given domain. In Chapter 7, we study the specific DNA base-water hydrogen bond lifetime (HBLT) dynamics at the major and the minor grooves of a hydrated duplex. The base-water HBLT correlation functions are in general multi-exponential and the average lifetime depends significantly on the specificity of the DNA sequence. The average HBLT is longer in the minor groove than that in the major groove by almost a factor of 2. Chapter 8 presents the solvation dynamics of constituent bases of aqueous DNA duplex. The solvation TCFs of the four individual bases display highly non-exponential decay with time. An interesting negative cross-correlation between water and counterions is observed which makes an important contribution to relaxation at intermediate to longer times. In the concluding note, Chapter 9 presents a brief summary of the outcome of the thesis and suggests several relevant problems that may prove w orthwhile to be addressed in future