A new class of materials, known as multi-functional energetic structural materials (MESMs), has been developed. These materials possess both strength and energetic functionalities, serving as candidates for many exciting applications. One of such applications is ballistic missiles, where these materials serve as part of structural casing as well as explosive payload. In this study, the dynamic compressive behavior of two types of MESMs in the intermediate strain rate regime is investigated. The first type is a thermite mixture of Al and Fe₂O₃ particles suspended in an epoxy matrix. The second type is a shock compacted mixture of Ni and Al powders. Compression experiments on a split-Hopkinson pressure bar (SHPB) apparatus are carried out at strain rates on the order of 103 s-1. In addition, a novel method for investigating the dynamic hardness of the Al + Fe₂O₃ + Epoxy materials is developed. In this method, high-speed digital photography is used to obtain time-resolved measurements of the indentation diameter throughout the indentation process. Experiments show that the shock compacted Ni-Al material exhibits a rather ductile behavior and the deformation of the Al + Fe₂O₃ + Epoxy mixtures is dominated by the polymer phase and significantly modulated by the powder phases. The pure epoxy is ductile with elastic-plastic hardening, softening, and perfectly plastic stages of deformation. The Al and Fe₂O₃ particles in Al + Fe₂O₃ + Epoxy mixtures act as reinforcements for the polymer matrix, impeding the deformation of the polymer chains, alleviating the strain softening of the glassy polymer matrix at lower levels of powder contents (21.6 - 29.2% by volume), and imparting the attributes of strain hardening to the mixtures at higher levels of powder contents (21.6 - 49.1% by volume). Both the dynamic and quasi-static hardness values of the Al + Fe₂O₃ + Epoxy mixtures increase with powder content, consistent with the trend seen in the stress-strain curves. To quantify the constitutive behavior of the 100% epoxy and the Al + Fe₂O₃ + Epoxy materials, the experimentally obtained stress-strain curves are fitted to the Hasan-Boyce model. This model uses a distribution of activation energies to characterize the energy barrier for the initiation of localized shear transformations of long chain polymeric molecules. The results show that an increase in powder content increases the activation energy, decreases the number of transformation sites, causes redistribution of applied strain energy, and enhances the storage of inelastic work. These effects lead to enhanced strength and strain hardening rate at higher levels of powder content.

Metal oxide-facilitated transformation is likely an important degradation pathway of antibacterial agents at soil-water interfaces. Phenolic disinfectants (triclosan and chlorophene), fluoroquinolones (FQs), and aromatic N-oxides are of particular concern due to their widespread usage, potential toxicity and frequent detection in the environment. Results of the present study show that the above antibacterial agents are highly susceptible to metal oxide-facilitated oxidation. The interfacial reactions exhibit complex reaction kinetics, which are affected by solution pH, the presence of co-solutes, surface properties of metal oxides, and structural characteristics of antibacterial agents. Adsorption of the antibacterial agents to Mn and Fe oxide surfaces generally proceeds faster than oxidation reactions of these compounds by Mn and Fe oxides, especially in the case of Fe oxides. Reaction intermediates and end products are identified by GC/MS, LC/MS and/or FTIR. Structurally-related model compounds are examined to facilitate reaction site and mechanism elucidation. On the basis of experimental results and literature, reaction schemes are proposed. In general, the antibacterial agent is adsorbed to the oxide surface, forming a precursor complex. Electrons are transferred within the precursor complex from the antibacterial agent to the oxide, followed by releasing of the radical intermediates which undergo further reactions to generate oxidation products. The precursor complex formation and electron transfer are likely rate-limiting. For triclosan, phenoxy radicals are critical intermediates to form oxidation products through three pathways (i.e., radical coupling, further oxidation of the radical, and breakdown of an ether bond within the radical). The first two pathways are also operative in the oxidation of chlorophene. For FQs, oxidation generates radical intermediates that are most likely centered on the inner N in the piperazine ring. The radical intermediates then undergo three major pathways (i.e., radical coupling, N-dealkylation, and hydroxylation) to yield a variety of products. For aromatic N-oxides, a N-oxide radical intermediate is generated upon oxidation by MnO2, followed by the loss of oxygen from the N-oxide moiety and the formation of a hydroxyl group at the C-atom adjacent to the N-oxide moiety. Overall, a fundamental understanding of the reaction mechanisms between three classes of antibacterial agents and metal oxides has been obtained.

The objective of the proposed research is to develop simplified reconfigurable transmission systems with frequency multipliers for the transmission of complex modulated signals. Because they rely on nonlinear properties, frequency multiplier-based transmission systems require proper linearization techniques and accurate modeling of the signal transfer function. To accomplish these two goals, the author has developed techniques to model and linearize frequency multipliers and to digitize feedback signals for nonlinear characterization. First, adaptive predistortion techniques and zonal transfer theories have been developed for modeling and linearization. The predistortion system has been verified by applying an IS-95B signal to various frequency multipliers built by the author. Second, because the output signals at higher harmonic zones occupy wider frequency bandwidths than the signal in the fundamental zone does and thus make it harder to use traditional sampling techniques, a simplified but effective method called the sub-Nyquist sampling rate was developed and verified. Third, two methods for reconfigurable transmitters using frequency multipliers in conjunction with digital predistortion linearizers were developed. Both methods make it possible to transmit complex signals via frequency multipliers by using dual-band transmission systems that incorporate frequency multipliers that are based on linearization techniques. One of these methods uses a circuit topology that can be switched between a fundamental-mode in-phase combined amplifier and a push-push frequency doubler using input phasing. The second suggested method uses a fundamental-frequency power amplifier followed by a varactor multiplier that can be bypassed with an RF switch. This work will contribute to the development of low-cost and size-effective reconfigurable transmission systems because it requires fewer transmitting components and needs less sampling of the feedback networks.

In recent years, smart gird has received much attention, and many researchers have devoted to home area network (HAN) to improve the efficiency of grid. This thesis proposes a bidirectional isolated DC-DC converter (Dual Active Bridge, DAB) with phase shift control to implement the concept of HAN. Li+Fe battery is used as storage device of the converter, and a bidirectional communication between Laboratory Virtual Instrumentation Engineering Workbench (LabVIEW) and Digital Signal Processor (DSP) is realized by CAN-bus. By setting the current command given by LabVIEW system, the converter is able to charge the Li+Fe battery with constant current and constant voltage method as well as discharge the Li+Fe battery with constant current. Operation principle of the converter and the associated loss are presented.

Initial forms of analytical models created to simulate real engineering structures may generally yield dynamic response predictions different than those obtained from experimental tests. Since testing a real structure under every possible excitation is not practical, it is essential to transform the initial mathematical model to a model which reflects the characteristics of the actual structure in a better way. By using structural model updating techniques, the initial mathematical model is adjusted so that it simulates the experimental measurements more closely. In this study, a sensitivity-based finite element (FE) model updating method using experimental frequency response (FRF) data is presented. This study bases on a technique developed in an earlier study on the computation of the so-called Mis-correlation Index (MCI) used for identifying the system matrices which require updating. MCI values are calculated for each required coordinate, and non-zero numerical values indicate coordinates carrying error. In this work a new model updating procedure based on the minimization of this index is developed. The method uses sensitivity approach. FE models are iteratively updated by minimizing MCI values using sensitivities. The validation of the method is realized through some case studies. In order to demonstrate the application of the method for real systems, a real test data obtained from the modal test of a scaled aircraft model (GARTEUR SM-AG19) is used. In the application, the FE model of the scaled aircraft is updated. In the case studies the generic software developed in this study is used along with some commercial programs.

In the present study, the powder metallurgy was evaluated as a technique to produce high performance Al &amp / #8211 / 8Fe &amp / #8211 / 1.7V &amp / #8211 / 7.9Si (wt%) alloys for elevated temperature applications and the role of powder particle size range and extrusion ratio in the microstructural and mechanical properties of the extruded alloys was investigated. For this purpose, an air atomization method was employed to produce powders of the high temperature alloy and after that the produced powders were sieved and cold compacted. The compacted billets were subsequently hot extruded at 450 &amp / #8211 / 480 &deg / C. Five selected ranges of powders which were different in particle size (&amp / #8722 / 2000+212 &amp / #956 / m, &amp / #8722 / 212+150 &amp / #956 / m, &amp / #8722 / 150+106 &amp / #956 / m, &amp / #8722 / 106+90 &amp / #956 / m, and &amp / #8722 / 90 &amp / #956 / m) and three different extrusion ratios (144:1, 81:1, and 26:1) were used in this study. In the first part of the thesis, microstructure and thermal stability of as &amp / #8211 / air atomized powders were described. &amp / #945 / &amp / #8211 / Al matrix and &amp / #945 / &amp / #8211 / Al13(Fe, V)3Si phases were characterized in all rapidly solidified powders by XRD. The fraction of the intermetallic phases was reduced as the powder particle size increased. DTA analysis revealed an exothermic reaction at 581 &deg / C in all alloy powders of different size fractions. In the second part of the study, the effect of powder particle size and extrusion ratio on microstructural and mechanical properties (at different temperatures) of the extruded alloys was investigated. The results showed that decrease in powder particle size and increase in extrusion ratio refined the microstructure and improved the mechanical properties. It was revealed that the effect of powder size was more evident than that of extrusion ratio. Remarkable increases in mechanical properties (e.g. 60.7% increase in ultimate tensile strength at 250 &deg / C) were observed as a result of rapid solidification process (atomization) and hot extrusion.

Samli Fe-oxide (+Cu&plusmn / Au) deposit is hosted by Samli pluton and rocks of Karakaya Complex in western Anatolia. The pluton consists of both mafic and felsic phases showing magma mixing textures. 40Ar/39Ar geochronology yielded an age range of 23.2&plusmn / 0.5 to 22.42&plusmn / 0.11 Ma for the Samli pluton, overlapping with 40Ar/39Ar age of 22.33&plusmn / 0.59 Ma and U-Pb age of 23.34&plusmn / 0.19 Ma from alterations. Sr-Nd isotope data are suggestive of a metasomatized subcontinental lithospheric mantle (SCLM) source for the magma. Alteration-mineralization pattern is defined by a series of overlapping halos characterized by sodic-calcic (plagioclase-pyroxene&plusmn / scapolite), calcic (garnet-pyroxene&plusmn / epidote), potassic (biotite+magnetite+chalcopyrite), hematite-limonite, and late stage (chalcedony-calcite+native Cu) alterations. Stable (&delta / 18O, &delta / 34S) and radiogenic (87Sr/86Sr,143Nd/144Nd) isotope compositions suggest a magmatic source for the fluids responsible for alteration-mineralization. Given the spatial-temporal association of alteration- mineralization with magmatic rocks, the hydrothermal system that controls mineralization in Samli appears to be linked with emplacement and cooling of Samli pluton. Samli Fe-oxide (+Cu&plusmn / Au) deposit has features characteristic for both skarn- and Iron-Oxide-Copper-Gold (IOCG) type deposits. The spatial and temporal association with a porphyritic intrusion, widespread calc-silicate assemblage, metal content (abundant Fe-oxide with high copper content) are similar to calcic Fe-Cu skarns, whereas low-Ti (&le / 0.05% TiO2) magnetite/hematite, low-S sulfides (chalcopyrite&gt / pyrite), high Cu (up to 6.78%) and moderate Au (up to 8.82 ppm) grades, local structural control in alteration-mineralization, and the derivation of the causative magma from a SCLM resembles the features pertinent to IOCG type mineralization. Therefore, Samli deposit is defined as a skarn type Fe-Cu mineralization with a potential for IOCG type deposit.

Composite laminates are an important subject of modern technology and engineering. The most common mode of failure in these materials is probably interlaminar fracture (delamination). Delamination growth under applied fatigue loads usually leads to structural integrity loss of the composite laminate, and hence its catastrophic failure. It is known that several parameters can affect the fatigue fracture performance of laminates. These include the constituent material properties, composite geometry, fatigue load variables or environmental factors. The knowledge about effects of these parameters on fatigue delamination growth can lead to a better understanding of composite fatigue fracture behaviour. Effects of some of these parameters can be elucidated by undertaking appropriate sensitivity analysis combined with the finite element method (FEM) and related software. The purpose of this work was three-fold. The first goal was the elaboration and computational implementation of FEM-based numerical strategies for the sensitivity analysis of interface fatigue crack propagation in elastic composite laminates. The second goal of this work was the numerical determination and investigation of displacement and stress fields near the crack tip, contact pressures along crack surfaces, mixed mode angle, energy release rate and the number of cumulative fatigue cycles. The third aim of the present study was to use the developed strategies to evaluate numerically the sensitivity gradients of the total energy release rate and fatigue life with respect to design variables of the curved boron/epoxy-aluminium (B/Ep-Al) composite laminate in two different material configurations under cyclic shear of constant amplitude. This study provided novel strategies for undertaking sensitivity analysis of the delamination growth under fatigue loads for elastic composite laminates using the package ANSYS. The numerical results of the work shed more light on mechanisms of interfacial crack propagation under cyclic shear in the case of a curved B/Ep-Al composite laminate. Moreover, the outcome of the sensitivity gradients demonstrated some advantages for using the sensitivity analysis to pinpoint directions for the optimisation of fatigue fracture performance of elastic laminates. The strategies proposed in this work can be used to study the sensitivity of the interface fatigue crack propagation in other elastic laminates, if the crack propagates at the interface between the elastic and isotropic components. However, the strategies can be potentially extended to composites with interfacial cracks propagating between two non-isotropic constituents under a constant amplitude fatigue load. Finally, the strategies can also be used to undertake the sensitivity analysis of composite fatigue life with respect to variables of fatigue load.

Quasikristallines Al-Cu-Fe (i-Phase) wurde ueber den Weg der amorphen (a-) Phase in Form duenner Schichten hergestellt und ein Vergleich elektronischer Transporteigenschaften der isotropen a-Phase in verschiedenen Anlassstufen mit der schliesslich entstehenden fast isotropen i-Phase durchgefuehrt (Leitfaehigkeit, Magnetoleitfaehigkeit, Hall-Effekt und Thermokraft). Die Auswirkungen einer Hume-Rothery-Stabilisierung auf den elektronischen Transport standen dabei im Vordergrund. Es wurden in der i-Phase auch die Auswirkungen einer systematischen Aenderung des Fe-Gehalts untersucht. Die a-Phase und die i-Phase sind in vielen wichtigen Trends miteinander verwandt, z.B. ist die inverse Matthiesen-Regel sowohl in der a- als auch in der i-Phase gueltig. Thermokraft und Hall-Effekt, die sehr empfindlich auf Aenderungen der Bandstruktur sind, zeigen drastischere Aenderungen beim Uebergang amorph-quasikristallin. Die Aenderungen der Eigenschaften in der i-Phase als Funktion der Temperatur und des Fe-Gehalts koennen in einem Zweibandmodell quantitativ erfasst werden. Mit dem Konzept der Spektralleitfaehigkeit, in das im Prinzip das Zweibandmodell uebergeht, koennen die Eigenschaften sowohl der i-Phase als auch der a-Phase quantitativ beschrieben werden. In der a-Phase fuehrt dieses Konzept auf eine sich von der frisch praeparierten a-Phase durch Tempern bis hin zur i-Phase kontinuierlich aendernde Spektralleitfaehigkeit, die schon unmittelbar nach dem Aufdampfen durch ein breites und ein, diesem ueberlagertes, schmales Minimum beschrieben werden kann. Beim Tempern wird das schmale Minimum immer tiefer. Im Ortsraum wird insgesamt ein Szenario vorgeschlagen, das von sphaerischer Ordnung ausgeht, zu der schon in der frisch praeparierten a-Phase eine Winkel- und Abstandsordnung hinzukommt. Diese verstaerkt sich beim Tempern bis hin zur perfekt geordneten Struktur in der i-Phase. Das Verschwinden magnetischer Effekte und die damit verbundenen Aenderungen der Tieftemperatur-Leitfaehigkeit beim Tempern deuten ebenfalls auf eine sich bereits in der a-Phase vollziehende kontinuierliche Aenderung der lokalen Umgebung der Fe-Atome, deren Anordnung hauptsaechlich die elektronischen Transporteigenschaften bestimmt.

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