The properties of functional materials have been studied with density functional theory. The first type of materials that have been investigated is the so called diluted magnetic semiconductors. It is a new class of materials that could offer enhanced functionality by making use of spin in addition to the charge of the electron. (Mn,Al) co-doped ZnO has been investigated regarding the Al significance on ferromagnetic behavior using density functional theory within the generalized-gradient approximation plus on-site Coulomb interaction. Despite the presence of Al the system always shows antiferromagnetic behavior. The role of intrinsic defects on ferromagnetism in pure and Cr doped In2O3 was also studied. For pristine In2O3, In vacancy and O interstitial states are completely spin polarized. Moreover, these hole states will create Cr ions in mixed valence state, giving rise to a strong ferromagnetic coupling. The second type of functional materials studied are hydrogen storage materials for mobile applications. These materials are considered as alternative if hydrogen is to replace fossil fuels as a energy carrier. In the view of this a series of compounds containing boron, nitrogen and hydrogen has been examined with respect to electronic structure, dehydrogenation energy and hydrogen diffusion properties. One compound, NH3BH3, has many desirable properties as a hydrogen storage material. In an effort to improve those properties, one of the H atoms in the NH3 group was replaced by Li, Na or Sr. The calculated hydrogen removal energies of the hydrogen release reactions were found to be significantly improved. Finally, a coating material, Al2O3, for wear resistant coatings on high performance cemented carbide cutting tools has been investigated. Chemical vapor deposition grown Al2O3 has been used for decades by the industry. To improve the growth process H2S is added to the gas mixture. The catalytic effect of H2S on the AlCl3/H2/CO2/HCl chemical vapor deposition process has been investigated on an atomistic scale. By applying a combined approach of thermodynamic modeling and density functional theory it seems that H2S acts as mediator for the oxygenation of the Al-surface which will in turn increase the growth rate of Al2O3.

Abstract This thesis studies the practical appraisal for pipeline inspection using the guided wave T(0,1) mode. The characteristic of reflected signals from the features of pipeline for various coated materials and fluid-filled pipes are also evaluated. The attenuation and the traveling distance of the guided wave are then calculated from the above-mentioned data for pipeline inspection in petro-chemical industries. In the experimental setup, the torsional mode is excited at one axial location using an array of transducers distributed around the circumference of the 6-inch test pipe. The reflected signals from various features, such as flanges, welds, supports, bends, defects and patches are analyzed at first at specific frequencies in the experiments. The effect of various coated material such as bitumen, PE and insulated material are also evaluated for the propagating torsional mode T(0,1) in the pipe. The results show that the attenuation of reflected signal is heavy for the bitumen-coated case because its viscosity is much higher than the other cases. Furthermore, the effect of pipe contents for defect detection using T(0,1) mode is investigated in this thesis. Various pipe contents, such as water, diesel oil, lubricant and fuel oil are deposit into the test pipe, respectively, to evaluate the influence to T(0,1). For the attenuation evaluation of reflected signal from flange in pipe, the reflected signal from an air-content pipe is measured for reference to compare with the measurements of other pipe contents in the experiments. The results show that the low viscosity liquid deposit in the pipe, such as water, diesel oil and lubricant, has no effect on the torsional mode; while the high viscous of the fuel oil deposit in the pipe attenuates the reflected signal heavily. It became evident that the torsional mode T(0,1) is most suitable for use in fluid-filled pipeline inspection.

The improvement in the impermeability of concrete was studied using different methods. The main aim was to investigate impermeability improvement of concrete and to compare these methods. Two different methods were examined to investigate and compare impermeability and strength improvement of concrete by using two different sets of concrete specimens. These methods included the application of coating materials to concrete and the production of concrete using different constituent amounts and types. The first set of concrete specimens was prepared by applying two different coating materials (a coating material including both powder and liquid components / and a coating material including only a liquid component) on reference concrete specimens separately. The second set of concrete specimens was prepared using different proportions of concrete constituents such as cement, water, steel and plastic fibers, mineral and chemical concrete admixtures. Various tests were conducted on both sets of concrete specimens in order to compare the permeability of concrete specimens. However, some of these tests v were not applied on all of the specimens because of test and material specifications. The tests were used to evaluate compressive strength, water absorption, chloride ion penetration and depth of water penetration under pressure. These test methods were carried out on concrete cube specimens and concrete cores taken from those specimens according to the relevant standards. It was found that the permeability of the concrete specimens decreased significantly when the coating material which was composed of the combination of powder and liquid components was applied on concrete specimens. However, permeability did not decrease significantly for concrete specimens coated with the coating material composed of only a liquid component. Significant improvement in the impermeability of the concrete specimens was observed when the amount of cement was increased, the water-to-cement ratio was decreased, mineral admixtures (silica fume and fly ash) and plasticizers were used. This improvement was associated with densification of the concrete microstructure and reduction in capillary pores as a result of pozzolanic reaction and due to reduction in water-to-cement ratio. Coating materials were determined to be effective for concretes with high permeability prior to coating whereas their effect was less significant for lower-initial permeability concretes. Moreover, the effect of coating materials on permeability differed depending on their chemical compositions. The effect of using steel fibers and plastic fibers for the improvement of concrete impermeability was found to be insignificant.

Thesis advisor: Matthias M. Waegele / Depositing metal-organic frameworks (MOFs) on the surfaces of metal nanoparticles (NPs) to enhance catalytic selectivity has recently attracted great attention; however, a solid understanding of how the NP-MOF interface promotes catalytic selectivity is lacking. In this thesis, we have conducted three fundamental studies and further applied the knowledge to other types of catalysts using enzymes. The first part of this thesis focuses on understanding the NP-MOF interfacial structures and their impact on catalytic performance. We have systematically probed the NP-MOF interface generated by three commonly used approaches by IR and Raman spectroscopy. We have revealed significant differences in interfacial chemical interactions between them, and have found that these differences in interfacial structure dramatically impact selectivity. For example, the interface generated by the coating approach contains trapped capping agents. This trapped capping agent reduces crotyl alcohol selectivity for the hydrogenation of crotonaldehyde. The second part of this thesis focuses on addressing the trapped capping agents at the NP-MOF interface. We developed an approach to creating a direct NP-MOF interface by utilizing weakly adsorbed capping agents during the MOF coating process. Their dynamic nature allows for their gradual dissociation from the NP surface with the assistance of the organic MOF linkers. Thus, direct chemical interactions can be built between NP and MOF, generating a clean and well-defined interface. Direct evidence on capping agent dissociation and formation of chemical interactions was obtained by Raman and IR spectroscopy. Combined with transmission electron microscopy and X-ray diffraction, we have revealed the relative orientation and facet alignment at the NP-MOF interface. The third part of this thesis investigates how various MOF components affect the selectivity of hydrogenation reactions catalyzed at the MOF-NP interface. We found that the replacement of Zr-oxo nodes with Ce-oxo nodes yields the highest selectivity for cinnamyl alcohol (~87%), whereas the functionalization of the terephthalic acid linker with -OH, CH3, -NO2 and NH2 groups only moderately modulates the selectivity relative to the Zr-UiO-66 (~58%). Reaction kinetics studies demonstrate that coating Pt NPs with Ce-UiO-66 increases the rate of C=O hydrogenation, which infrared spectroscopic observations suggest is due to the interaction of the C=O group with the Ce-oxo node. This work highlights the critical role of metal-oxo nodes in regulating the catalytic selectivity of metal NPs in specific reactions. The fourth part of this thesis extends the interface control to other catalysts involving enzymes. We compared the interfacial interactions of catalase in solid and hollow MOF microcrystals. The solid sample with confined catalase was prepared through a reported method. The hollow sample was generated by hollowing the MOFs crystal, sealing freestanding enzymes in the central cavities of the hollow MOF. By monitoring this hollowing process, we observed that the enzymes gradually changed from a confined form to a freestanding form. The freestanding enzymes in the hollow MOFs show higher activity in the decomposition of hydrogen peroxide, attributed to their lesser chemical interactions and confinement. This study highlights the importance of the freestanding state for the biological function of encapsulated enzymes. Taken together, the four sections in this thesis establish design rules for refining MOF-based catalyst design. / Thesis (PhD) — Boston College, 2022. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

The primary focus of this research is to utilize cellular and polymeric membranes for biomedical applications: To date, several organic and inorganic materials have been used to synthesize nanoparticles (NPs). The question arises as to which criteria and design principles should be considered while selecting the best material. Based on the results of testing, three key roles of NPs have been identified. First, NPs need enough circulation time to reach their target. Then these NPs must be able to target diseased tissue while leaving healthy tissue unaffected. Finally, NPs must be biodegradable and easily eliminated from the body. Biomimetic nanoparticles based on cell membranes have been developed as an efficient way to fulfill the needs of drug delivery goals and achieve targeted delivery by actively interacting and communicating with the biological environment. In the first project, genome editing machinery was delivered to particular cells using biomimetic cancer cell coated zeolitic imidazolate frameworks. MCF-7 cells demonstrated the highest uptake of C3-ZIFMCF compared to HeLa, HDFn, and aTC cells. In terms of genome editing, MCF-7 cells transfected with C3-ZIFMCF showed 3-fold EGFP repression compared to C3-ZIFHELA cells transfected with 1-fold EGFP repression. In vivo tests demonstrated C3-ZIFMCF's affinity for MCF-7 tumor cells. This demonstrates the biomimetic approach's ability to target cells specifically, which is definitely the most essential step in future genome editing technology translation. In the second project, multimodal therapeutic nanowires (NWs D-ZIF) MCF-7 cancer cells were developed. D-ZIF coated NWs had higher cellular uptake and photothermal treatment efficiency than non-coated NWs. (NWs D-ZIF) MCF accumulates in MCF-7 tumor cells and enhances photothermal capability. On the other hand, chiral separation of enantiomers is becoming more important, particularly in pharmaceuticals. Because enzyme activities and other biological processes are stereoselective, chiral drugs' enantiomers often have different metabolic effects, pharmacological activity, metabolic rates, and toxicities. In an attempt to address this issue, we decided in the final project to study the capability of chiral polyamide membrane for efficient and energy-free chiral separation. In particular, to separate essential amino acid critical to all living organisms (DL-tryptophan).

Membrane technology has been used in water purification for decades. However, membrane fouling remains a limiting factor. One way to control fouling is through surface modification. Several studies report that increasing surface hydrophilicity can reduce membrane fouling. Surface modification via physical coating (i.e., thin-film composite membrane) was explored in this research to prevent membrane fouling. Before making thin-film composite membranes, it was important to study structure/property relations in a series of potential coating materials. This research aims to contribute to a better fundamental understanding of the structure/property relations which govern water transport, rejection of model foulants (i.e., emulsified oil droplet or protein), and fouling characteristics in hydrogels based on poly(ethylene glycol) diacrylate (PEGDA) and N-vinyl-2-pyrrolidone (NVP). Crosslinked poly(ethylene glycol) (PEG) free-standing films were prepared by UV-induced photopolymerization of PEGDA crosslinker in the presence of varying amounts of water or monofunctional poly(ethylene glycol) acrylate (PEGA). The crosslinked PEGDA films exhibited polymerization induced phase separation (PIPS) when the water content of the prepolymerization mixture was greater than 60 wt%. Visible light absorbance measurements, water uptake, water permeability, and salt kinetic desorption experiments were used to characterize the structure of these phase-separated, crosslinked hydrogels. The films with PIPS exhibited a porous morphology in cryogenic scanning electron microscope (CryoSEM) studies. Dead-end filtration experiments using deionized water and bovine serum albumin (BSA) solutions were performed to explore the fundamental transport and fouling properties of these materials. The total flux of pure water through the films after prior exposure to BSA solution was nearly equal to that of the as-prepared material, indicating that these PEGDA films resist fouling by BSA under the conditions studied. Crosslinked NVP free-standing films were prepared by UV-induced photopolymerization in the presence of water, with NVP as the monomer and N,N’-methylenebisacrylamide (MBAA) as the crosslinker. A series of crosslinked films were polymerized at various prepolymerization water contents, NVP/MBAA ratios and at various levels of UV light intensity in the polymerization. Like PEGDA, the NVP films also underwent phase-separation during polymerization. The influence of monomer/ crosslinker ratio, prepolymerization water content, and UV intensities on membrane morphology and water transport was characterized with CryoSEM, bio-atomic force microscope (Bio-AFM) and dead-end filtration. Molecular weight cutoff (MWCO) measurements were used to characterize the sieving property of crosslinked NVP films polymerized at different UV intensities. UV intensity was found to have an impact on the interconnectivity of crosslinked membranes. Finally, tests of fouling resistance to protein solution (bovine serum albumin) and oily water emulsion were performed. The NVP crosslinked films had good protein and oily water fouling resistance. Overall, both crosslinked PEGDA and NVP films exhibit fouling resistance to oily water emulsions or protein solution. NVP films had more porous structure and higher water permeability than did PEGDA films, while the more compact structure of PEGDA films led to better rejection of model foulants (e.g., protein) than in NVP films. Based on different applications (e.g., oil/water separation, protein filtration), different coating materials must be chosen according to the membrane morphology, transport property, and rejection of model foulants to achieve the highest water flux and foulant rejection in membranes used for water purification. / text

This master´s thesis is aimed at the analyse of the production of lacquers and paints and at its expansion in the Sherwin-Williams Czech republic company. At first particular activities of the company are presented and then several variants of the expansion are suggested, among them belongs the implementation of the operation in shifts, the modernization of equipment and the increase in the number of workers. After the exploration of influences of these variants on logistic processes and the exploration of related costs and merits the modernization is chosen as the optimal variant for the expected level of the demand.