Compound Aircraft Transport (CAT) flight involves two or more aircraft using the resources of each other; a symbiotic relationship exists consisting of a host, the mothership aircraft and a parasite, the hitchhiker aircraft. Wingtip-docked flight is just as its name implies; the two aircraft are connected wingtip-to-wingtip. Formation flight describes multiple aircraft or flying objects that maintain a pattern or shape in the air. There are large aerodynamic advantages in CAT flight. The aforementioned wingtip-docked flight increases total span of the aircraft system, and formation flight utilizes the upwash from the trailing wingtip vortex of the lead aircraft (mothership) to reduce the energy necessary to achieve and/or maintain a specific flight goal for the hitchhiker and the system. The Stability Wind Tunnel (6 X 6 X 24 foot test section) at Virginia Tech, computational aerodynamic analysis with the vortex lattice method (VLM), and a desktop aircraft model were used to answer questions of the best location for a hitchhiker aircraft and analyze stability of the CAT system. Wind tunnel tests implemented a 1/32 scale F-84E model (hitchhiker) and an outboard wing portion representing a B-36 (mothership). These models were chosen to simulate flight tests of an actual wingtip-docked project, Tom Tom, in the 1950s. That project was terminated after a devastating accident that demonstrated a possible "flapping" motion instability. The wind tunnel test included a broad range of hitchhiker locations: varying spanwise gap distance, longitudinal or streamwise distance, and vertical location (above or below wing) with respect to a B-36-like wing. The data showed very little change in the aerodynamic forces of the mothership, and possibilities of large benefits in lift and drag for the hitchhiker when located slightly aft and inboard with respect to the mothership. Three CAT flight configurations were highlighted: wingtip-docked, close formation, and towed formation. The wingtip-docked configuration had a 20-40 percent performance benefit for the hitchhiker compared to solo flight. The close formation configuration had performance benefits for the hitchhiker approximately 10 times that of solo flight, and the towed formation was approximately 8 times better than solo flight. The VLM analysis completed and reenforced the experimental wind tunnel data. A modified VLM program (VLM CAT) incorporated multiple aircraft in various locations as well as additional calculations for induced drag. VLM CAT results clearly followed the trends seen in the wind tunnel data, but since VLM did not model the fuselage, has assumptions like a flat wake, and is an inviscid computation it did not predict the large benefits or excursions as seen in the wind tunnel data. Increases in performance for the hitchhiker in VLM CAT were on the order of 3 to 4 times that of the hitchhiker in solo flight, while the wind tunnel study saw up to 10 times that of solo flight. VLM CAT is a valuable tool in supplying quick analysis of position and planform effects in CAT flight. Modifications to a desktop F-16 dynamic simulation have been developed to investigate the stability of wingtip-docked flight. These modifications analyze the stability issues linked with sideslip angle as seen by the Tom Tom Project test pilot, when he entered docking maneuvers with 5 degrees yaw to simulate a ``tired pilot". The wingtip-docked system was determined to have an unstable aperiodic mode for sideslip angle greater than 0.0 degrees and an unstable oscillatory mode for sideslip angle greater than 2.0 degrees. There is a small range of sideslip angle that is a stable oscillatory mode, sideslip angle between 0.0 and 2.0 degrees. The variables, altitude and speed, yield little effect on the stability of the system. The sensitivity analysis was indeterminate in distinguishing a state driving the instability, but the analysis was conclusive in verifying the lateral-longitudinal (roll-pitch) coupled motion observed by test pilots in wingtip-docked flight experiments. The parameter with the largest influence on the instability was the change in pitch angular acceleration with respect to roll angle. The aerodynamic results presented in this study have determined some important parameters in the location of a hitchhiker with respect to a mothership. The largest aerodynamic benefits are seen when the hitchhiker wingtip is slightly aft, inboard and below the wingtip of the mothership. In addition, the stability analysis has identified an instability in the CAT system in terms of sideslip angle, and that the wingtip-docked hitchhiker is coupled in lateral and longitudinal motion, which does concur with the divergent "flapping" motion about the hinged rotational axis experienced by the Tom Tom Project test pilot. / Ph. D.

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

Thesis advisor: X. Peter Zhang / Chapter 1. Co(II)-Based Metalloradical Catalysis for Stereoselective Radical Cyclopropanation of Alkenes This Account summarizes our group’s recent efforts in developing metalloradical catalysis as a one-electron approach for catalytic radical cyclopropanation of alkenes with diazo compounds. Chapter 2. Asymmetric Radical Process for General Synthesis of Chiral Heteroaryl Cyclopropanes We have developed a Co(II)-based metalloradical system that is highly effective for asymmetric radical cyclopropanation of alkenes with in situ-generated heteroaryldiazomethanes. Through fine-tuning the cavity-like environments of newly developed D2-symmetric chiral amidoporphyrins as the supporting ligand, the optimized Co(II)-based metalloradical system is broadly applicable to pyridyl and other heteroaryldiazomethanes for asymmetric cyclopropanation of a wide range of alkenes, providing general access to valuable chiral heteroaryl cyclopropanes in high yields with excellent diastereoselectivities and enantioselectivities. Chapter 3. Enantioselective Metalloradical 1,6-C–H Alkylation of In Situ-Generated Alkyldiazomethanes for Synthesis of Chiral Piperidines We have disclosed an effective Co(II)-based metalloradical system as a fundamentally different approach to harness the potential of 1,6-HAA radical process, enabling asymmetric 1,6-C–H alkylation of in situ-generated alkyldiazomethanes to construct chiral piperidines. Supported by an optimal D2-symmetric chiral amidoporphyrin ligand, the Co(II)-catalyzed alkylation system is capable of activating a wide array of alkyldiazomethanes containing C(sp3)–H bonds with varied steric and electronic properties, providing access to chiral piperidines in good to high yields with high enantioselectivities from readily accessible 4-aminobutanal derivatives. In addition to practical attributes, such as operational simplicity and mild conditions, the metalloradical system is highlighted by its tolerance to different functional groups as well as compatibility with heteroaryl units. Chapter 4. Design and Synthesis of A Novel D2-Symmetric Chiral Porphyrin for Co(II)-Based Metalloradical Catalysis A novel D2-symmetric chiral amidoporphyrin derived from chiral cyclopropanecarboxamide containing diphenyl units has been effectively constructed based on Co(II)-catalyzed asymmetric cyclopropanation of alkenes. / Thesis (PhD) — Boston College, 2022. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

Recent studies have provided conflicting results in regards to equine intradermal skin testing and its use in defining causative antigens in IgE mediated diseases such as equine recurrent airway obstruction (RAO). This study was divided into two experiments. In the first experiment of this study, the hypothesis tested was normal horses would have minimal variability in the wheals formed by intradermal injection of positive control stimulants. This was evaluated by examining the repeatability of skin test wheals created by 5 concentrations of histamine, compound 48/80, and phaseolus vulgaris (PHA) within a normal horse and between 12 normal horses at 0.5 hours, 4 hours, and 24 hours post injection. Minimal variability was detected within individual horses and between 12 horses for histamine and compound 48/80 at 0.5 hours and for PHA at 4 hours. This information suggests that the intradermal injection of positive control substances is a repeatable test in normal horses. In the second experiment of this study, the hypothesis tested was normal horses react differently to intradermal injection of positive control stimulants (histamine, compound 48/80, PHA) and/or an environmental antigen (Aspergillus) in comparison to horses affected with RAO. This was evaluated by identifying differences in wheal responses between normal horses and RAO affected horses. Concentration response curves were created in normal and RAO affected horses to the aforementioned stimulants at 0.5 hours, 4 hours, and 24 hours post injection. No statistically significant differences were noted in concentration response between normal and ROA affected horses when compound 48/80 and PHA were evaluated. RAO affected horses demonstrated a greater slope at the 0.5 hour time when compared to normal horses suggesting that RAO affected horses are hypersensitive to intradermal injection of histamine. Injection of Aspergillus mix at 4000 protein nitrogen units/ml caused an intradermal wheal reaction at the 24-hour time in 4/5 RAO horses. This reaction was not noted in normal horses. This information suggests that there may be a positive relationship between causative antigens (i.e. Aspergillus) that may induce clinical RAO and positive intradermal skin test results. An additional aspect that was evaluated in both experiments involved histologic examination of skin biopsies taken from wheals created by intadermal injection of histamine, compound 48/80, PHA, and Aspergillus at various times post injection. In the first experiment, intradermal injection of histamine caused severe dermal edema and margination of neutrophils and eosinophils at 0.5 hours. Compound 48/80 demonstrated mild to modest dermal edema at 0.5 hours while PHA demonstrated severe dermal edema, hemorrhage, and lymphactic ectasia at 4 and 24 hours. PHA also demonstrated a neutophilic inflammation at 4 hours that progressed to a mixed lymphohistiocytic and neutrophilic inflammation at 24 hours. In the second experiment, no edema and modest to moderate neutrophilic inflammation was noted in normal horses after intradermal injection of Aspergillus at 24 hours. In contrast, RAO affected horses demonstrated mild to modest edema and a mild to moderate mixed inflammatory response (lympho-histocytic, neutrophilic, eosinophilic) after intradermal injection of Aspergillus at 24 hours suggesting a delayed type response. / Master of Science

Landslides cause significant damage worldwide and therefore epitomize the most important problems in geotechnical engineering. Hence, perceiving the mechanics involved in the deformation process of landslides is necessary for risk assessment. In addition to the resistance offered by basal shear surfaces, internal shearing also influences the stability and kinematics of compound landslides. For compound landslides, internal shearing is essential to develop feasible sliding mechanisms. The internal distortion is caused by the formation of shear bands that develop within the sliding mass. The strain localization is generally attributed to slope changes along the basal sliding surface (or topography) that constrain the strain field of the landslide. The development of these internal shear bands also controls the energy dissipation, and its distribution determines the final degradation of the material. This work focuses on the study of internal failure mechanisms that develop in compound landslides. A theoretical model of a compound landslide is numerically analyzed using the Material Point Method (MPM), a state-of-the-art numerical technique appropriate to model large deformation problems. The internal failure pattern is identified for different basal sliding geometries. Based on that, a generalized method is proposed to estimate the internal failure mechanism of bi-planar compound geometries. The material degradation and energy dissipation are evaluated in terms of the accumulated deviatoric strain and the reaction forces exerted by the landslide on a vertical wall. Moreover, preliminary studies are conducted to analyze the use of barriers as a mitigation strategy to counter landslide damage, and their efficiencies are investigated. / Master of Science / Landslides consist of movement of rock and debris down a slope. They cause substantial damage each year and therefore represent an important class of problems in geotechnical engineering. Understanding the deformation process and internal shearing pattern occurring in landslides is an important aspect for assessing the risk that a landslide poses. The internal shear is caused due to the formation of shear bands that develop within the mass flowing down the slope and originate at the points of slope change on an incline. These shear bands also affect the amount of energy dissipated and the degradation of flow material. In this work, the internal failure mechanism in landslides is analyzed and effects on landslide kinematics are studied. Material Point Method (MPM) is used to simulate slope instabilities which is an advanced numerical technique appropriate for modeling large deformation problems such as landslides. Several theoretical models of compound landslides are presented considering variation in geometry (roundedness), friction, and slope angle. A generalized failure mechanism of a landslide is proposed based on its geometry and physical parameters. Finally, accumulated strains and reaction forces impacted by moving mass on a wall are calculated for different landslide geometries, and subsequently correlated to energy dissipation material degradation. These results also serve as a precursor to studying the role of barriers in mitigating landslide damage.

The tire-terrain interaction is complex and tremendously important; it impacts the performance and safety of the vehicle and its occupants. Icy roads further enhance these complexities and adversely affect the handling of the vehicle. The analysis of the tire-ice contact focusing on individual aspects of tire construction and operation is imperative for tire industry's future. This study investigates the effects of the tread rubber compound on the drawbar pull performance of tires in contact with an ice layer near its melting point. A set of sixteen tires of eight different rubber compounds were considered. The tires were identical in design and tread patterns but have different tread rubber compounds. To study the effect of the tread rubber compound, all operational parameters were kept constant during the testing conducted on the Terramechanics Rig at the Terramechanics, Multibody, and Vehicle Systems laboratory. The tests led to conclusive evidence of the effect of the tread rubber compound on the drawbar performance (found to be most prominent in the linear region of the drawbar-slip curve) and on the resistive forces of free-rolling tires. Modeling of the tire-ice contact for estimation of temperature rise and water film height was performed using ATIIM 2.0. The performance of this in-house model was compared against three classical tire-ice friction models. A parametrization of the Magic Formula tire model was performed using experimental data and a Genetic Algorithm. The dependence of individual factors of the Magic Formula on the ambient temperature, tire age, and tread rubber compounds was investigated. / Master of Science / The interaction between the tire and icy road conditions in the context of the safety of the occupants of the vehicle is a demanding test of the skills of the driver. The expected maneuvers of a vehicle in response to the actions of the driver become heavily unpredictable depending on a variety of factors like the thickness of the ice, its temperature, ambient temperature, the conditions of the vehicle and the tire, etc. To overcome the issues that could arise, the development of winter tires got a boost, especially with siping and rubber compounding technology. This research focuses on the effects on the tire performance on ice due to the variation in the tread rubber compounds. The experimental accomplishment of the same was performed using the Terramechanics rig at the Terramechanics, Multibody, and Vehicle Systems (TMVS) laboratory. It was found that the effect of the rubber compound is most pronounced in the region where most vehicles operate under normal circumstances. An attempt was made to simulate the temperature rise in the contact patch and the water film that exists due to the localized melting of ice caused by frictional heating. Three classical friction models were used to compare the predictions against ATIIM 2.0, an in-house developed model. Using an optimization technique namely the Genetic Algorithm, efforts were made to understand the effects of the tread rubber compound, the ambient temperature, and the aging of the tire on the parameters of the Magic Formula model, an empirical model describing the performance of the tire.

Gas Chromatography (GC) is an analytical technique in the chemistry field widely used to separate compounds present in a sample mixture. Conventional GC systems are an extremely versatile and powerful tool to perform complex separations. However, these systems come with the cost of being bulky and requiring a high amount of power for operation. With considerable research for over 40 years, the advent of Micro-Gas Chromatography (µGC) made it possible for miniaturized, compact, low-power, and field portable GC systems. This thesis presents a portable µGC system that enables real-time analysis of complex compound separations, made possible with the use of multiple separation columns and a novel multidimensional compound identification algorithm. The system architecture and the software design with multiple features enabling portability of the µGC system are discussed. A set of microfabricated separation columns (µSCs) and photoionization detectors (PIDs) are integrated to realize a fully functional µGC system that is tested with different types of complex compound mixtures. An in-depth analysis of processing the output chromatograms obtained from the setup for signal filtering and peak detection is described in this thesis. A multidimensional analysis for compound identification in complex mixtures is presented. / Master of Science / Volatile organic compounds (VOCs) are generally chemicals that have high vapor pressure and low boiling points used and produced in the processing of petroleum products, paint, refrigerants, pharmaceuticals, and adhesives. VOCs are emitted as gases from certain solids or liquids, some of which may have short- and long-term adverse health effects even with minute exposure. Gas Chromatography (GC) is a common analytical technique used to detect, identify, and quantify VOCs in the environment, and conventional GC Systems have been utilized for this purpose. The separation of compounds occurs inside an analytical column that has selective interaction between the column and the analytes passing through. However, these systems are expensive, bulky, consume high power, and require expertise to operate. Recently, advancements in the Microelectromechanical systems (MEMS) field has paved the way to create Micro-Gas Chromatography (µGC) systems with improved performance when compared to traditional systems. Active research is ongoing to improve the portability of µGC systems for reliable and quick on-field analysis. In this thesis, we present a µGC system that has a robust and scalable design that allows the development of a portable µGC system. The compound separation of complex mixtures is showcased using the portable µGC system setup. The output chromatograms obtained from the µGC system are pre-processed, which involves noise filtering and peak detection, followed by an analysis using a multidimensional compound identification algorithm.

Yes / Cancer is now the second-leading cause of mortality and morbidity, behind only heart disease, necessitating urgent development of (chemo)therapeutic interventions to stem the growing burden of cancer cases and cancer death. Plants represent a credible source of promising drug leads in this regard, with a long history of proven use in the indigenous treatment of cancer. This study therefore investigated Anacardium occidentale, one of the plants in a Nigerian Traditional Medicine formulation commonly used to manage cancerous diseases, for cytotoxic activity. Bioassay-guided fractionation, spectroscopy, Alamar blue fluorescence-based viability assay in cultured HeLa cells and microscopy were used. Four compounds: zoapatanolide A (1), agathisflavone (2), 1, 2-bis (2,6-dimethoxy-4-methoxybenzoyl) ethane (Anacardicin, 3) and methyl gallate (4) were isolated, with the most potent being zoapatanolide A with an IC50 value of 36.2 ± 9.8 μM in the viability assay. To gain an insight into the likely molecular basis of their observed cytotoxic effects, Autodock Vina binding free energies of each of the isolated compounds with seven molecular targets implicated in cancer development (MAPK8, MAPK10, MAP3K12, MAPK3, MAPK1, MAPK7 and VEGF), were calculated. Pearson correlation coefficients were obtained with experimentally-determined IC50 in the Alamar blue viability assay. While these compounds were not as potent as a standard anti-cancer compound, doxorubicin, the results provide reasonable evidence that the plant species contains compounds with cytotoxic activity. This study provides some evidence of why this plant is used ethnobotanically in anti-cancer herbal formulations and justifies investigating Nigerian medicinal plants highlighted in recent ethno-botanical surveys. / This work was supported by a British Council Researcher Links Travel Grant 2013 to TBJ, a South Africa’s National Research Foundation (NRF) Grant No 98345, 2016 to FRVH and an academic staff funding provided to AAF by the School of Pharmacy, University of Bradford, UK.

Yes / Ice cover formed on a river surface is a common natural phenomenon during winter season in cold high latitude northern regions. For the ice-covered river with compound cross-section, the interaction of the turbulence caused by the ice cover and the channel bed bottom affects the transverse mass and momentum exchange between the main channel and floodplains. In this study, laboratory experiments are performed to investigate the turbulent flow of a compound channel with shore ice covered on the floodplains. Results show that the shore ice resistance restricts the development of the water flow and creates a relatively strong shear layer near the edge of the ice-covered floodplain. The mean streamwise velocity in the main channel and on the ice-covered floodplains shows an opposite variation pattern along with the longitudinal distance and finally reaches the longitudinal uniformity. The mixing layer bounded by the velocity inflection point consists of two layers that evolve downstream to their respective fully developed states. The velocity inflection point and strong transverse shear near the interface in the fully developed profile generate the Kelvin-Helmholtz instability and horizontal coherent vortices. These coherent vortices induce quasi-periodic velocity oscillations, while the dominant frequency of the vortical energy is determined through the power spectral analysis. Subsequently, quadrant analysis is used in ascertaining the mechanism for the lateral momentum exchange, which exhibits the governing contributions of sweeps and ejections within the vortex center. Finally, an eddy viscosity model is presented to investigate the transverse momentum exchange. The presented model is well validated through comparison with measurements, whereas the constants α and β appeared in the model need to be further investigated. / National Natural Science Foundation of China (NSFC). Grant Numbers: 52020105006, 11872285: State Key Laboratory of Water Resources and Hydropower Engineering Science (WRHES), Wuhan University. Grant Number: 2018HLG01

京都大学 / 新制・課程博士 / 博士(理学) / 甲第25135号 / 理博第5042号 / 新制||理||1719(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 依光 英樹, 教授 畠山 琢次, 教授 松永 茂樹 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM