This dissertation summarizes research efforts focused on the use of boron and transition metal halides to form new carbon-carbon and carbon-halide bonds. The boron halide mediated alkyne-aldehyde coupling reaction to generate 1,3,5-triaryl-1,5-dihalo-1,4-dienes was reinvestigated in an attempt to explain the stereochemistry observed during changing of both the mode of addition and the reaction temperature. Either (Z,Z)-1,4-dienes or (Z,E)-1,4-dienes can be the predominant product depending on reaction conditions used. This mechanistic investigation also led to the discovery of several novel reactions. These include the stereoselective preparation of (Z)-3-chloroallylic ethers from the reaction of alkenylboron dichlorides with aryl aldehydes in the presence of an amine; the titanium(IV) halide coupling of alkoxides and alkynes; the haloallylation of aryl aldehydes with boron trihalide using different allylmetals; and the base induced elimination of the haloallylated products to form 1,3-dienes. The results of these studies strongly imply a cationic mechanism. The new reactions described herein can be characterized as atom-efficient, environmentally friendly, and capable of generating the desired products in good to excellent yields.

Halogen bonding (XB), the interaction between electron deficient halogen compounds and electron donors, is an established non-covalent interaction in the solid and gaseous phases. Understanding of XB in the solution phase is limited. This thesis describes experimental studies of XB interactions in solution, and the application of XB interactions in anion recognition. Chapter 1 is a brief review of current understanding of XB interaction: theoretical models, studies of XB in solid and gaseous phases and examples in biological systems are discussed. At the end of this chapter, halogen bonding in the solution phase is discussed, along with applications of halogen bonding in organic syntheses. In chapter 2, linear free energy relationships involving the thermodynamics of halogen bonding of substituted iodoaromatics are studied. The utility of substituent constants and calculated molecular electrostatic potential values as metrics of halogen bond donor ability are discussed. Density Functional Theory (DFT) calculations are shown to have useful predictive values for trends in halogen bond strength for a range of donor-acceptor pairs. Chapter 3 describes the development of new multidentate anion receptors based on halogen bonding. Bidentate and tridentate receptors were found to exhibit significantly higher binding constants than simple monodentate donors. These receptors show selectivity for halide anions over oxyanions. Using 19F NMR spectra at different temperature, the enthalpies and entropies of anion bindings for monodentate and tridentate receptors were determined. The results indicate a positive entropy contribution to anion binding for both mono and tridentate receptors in acetone solvent. Finally in chapter 4, some mesitylene based receptors with 3-halopyridinium and 2-iodobenzimidazolium donors are introduced. The receptors perform halide anion recognition in aqueous solvent system through charge-assisted XB interactions. These findings can allude to utility in organic synthesis, supramolecular chemistry and drug design.

Halogen bonding (XB), the interaction between electron deficient halogen compounds and electron donors, is an established non-covalent interaction in the solid and gaseous phases. Understanding of XB in the solution phase is limited. This thesis describes experimental studies of XB interactions in solution, and the application of XB interactions in anion recognition. Chapter 1 is a brief review of current understanding of XB interaction: theoretical models, studies of XB in solid and gaseous phases and examples in biological systems are discussed. At the end of this chapter, halogen bonding in the solution phase is discussed, along with applications of halogen bonding in organic syntheses. In chapter 2, linear free energy relationships involving the thermodynamics of halogen bonding of substituted iodoaromatics are studied. The utility of substituent constants and calculated molecular electrostatic potential values as metrics of halogen bond donor ability are discussed. Density Functional Theory (DFT) calculations are shown to have useful predictive values for trends in halogen bond strength for a range of donor-acceptor pairs. Chapter 3 describes the development of new multidentate anion receptors based on halogen bonding. Bidentate and tridentate receptors were found to exhibit significantly higher binding constants than simple monodentate donors. These receptors show selectivity for halide anions over oxyanions. Using 19F NMR spectra at different temperature, the enthalpies and entropies of anion bindings for monodentate and tridentate receptors were determined. The results indicate a positive entropy contribution to anion binding for both mono and tridentate receptors in acetone solvent. Finally in chapter 4, some mesitylene based receptors with 3-halopyridinium and 2-iodobenzimidazolium donors are introduced. The receptors perform halide anion recognition in aqueous solvent system through charge-assisted XB interactions. These findings can allude to utility in organic synthesis, supramolecular chemistry and drug design.

Plants are exposed to a variety of environmental stresses, ranging from insects and phytopathogens known as biotic stressors, to edaphic stressors including drought and salinity - clustered under the group of abiotic stresses. Facing these pernicious risks, plants have adopted several strategies to survive in stressful environments. With contemporary advances in technology and scientific research, it is possible to insert a specific gene or trait into a plant in order to confer salt tolerance. For example, a thiol methyltransferase enzyme in cabbage converts Cl¯ and other halide ions into their corresponding methyl halides, which are released directly into the air. Cloning the TMT1 gene and functionally expressing this gene into tobacco plants conferred salt tolerance on these plants. Although increased salt tolerance is a favourable and beneficial trait for plant productivity, the emission of methyl halides into the atmosphere can be noxious for the environment. Indeed, methyl halides are some of the factors contributing to climate change, widely believed to be the foremost environmental problem of the twenty-first century. Climate change is affecting all forms of life on earth and its impacts are often severe and irreversible. For that reason, it has been placed at the forefront of the international political agenda. The present study focused on two main physiological traits of stress resistance in tobacco plants which have been genetically engineered with the cabbage TMT1 gene: The production of methyl halides, particularly methyl chloride, as a way to confer salt tolerance; and synthesis of the stress hormone, ethylene. Both pathways share a common metabolite, S-adenosyl-L-methionine (SAM), for the synthesis of the final products. SAM, derived from the amino acid methionine (Met), is a universal methyl group donor. It plays essential roles in plant metabolism, by acting as a precursor for ethylene, polyamines, and vitamin B1 synthesis, and as a source of atmospheric dimethylsulphides. Therefore, it is important that the plant maintains the SAM pool at a level sufficient to serve all the different metabolic pathways. The present work set out to determine whether addition of another SAM-dependent pathway through TMT insertion in tobacco plants would negatively affect ethylene synthesis by lessening the amount of SAM available for ethylene biosynthesis. Detailed experimental studies were conducted, including in vitro and in vivo experiments, to examine the potential effect of TMT gene insertion on SAM availability for ethylene synthesis in tobacco plants. Three series of in vitro tests, differing by the number of leaf discs used, the final headspace volume in each flask, the incubation period in the different solutions and the time of introducing salt solutions, were carried out. Data obtained from two series of in vitro experiments revealed a decrease in ethylene emission when salt solutions were added at the beginning of the experiment and when leaves where incubated overnight in the presence of 0.1 M NaBr, coupled with the production of methyl halides, whereas the other series of in vitro tests as well as the in vivo results showed no alteration in ethylene accumulation because of TMT insertion when tobacco leaves were exposed to salt treatments. According to the results presented in this study, the amounts of available SAM in transformed tobacco are likely sufficient to serve both ethylene and methyl halides biosynthetic pathways. Besides, in vivo results indicate that inserting the TMT1 gene that improves salt stress resistance in tobacco should not dramatically alter ethylene synthesis, and therefore, would be unlikely to affect any physiological trait associated with ethylene production if this gene is used to engineer salt tolerance in high-value crops. Although TMT insertion does not alter ethylene emission in transgenic plants and tends to be an efficient tool to confer salt tolerance in halo-intolerant crops, its environmental cost is of great concern and, therefore, should be taken into consideration to mitigate the amounts of methyl halides emitted into the atmosphere because of this insertion.

The dissertation investigates the starting transient behaviors of metal halide lamps driven by constant currents and constant powers, respectively. Based on the investigation results, three starting scenarios are proposed for shortening the starting time, and an identification strategy is figured out for designing an electronic ballast being capable of driving three small-wattage lamps rated at different powers. A laboratory electronic ballast is designed to drive small-wattage metal halide lamps with a programmable low-frequency square-wave current. Experiments are conducted to examine the effects of the starting current on variations of the light output as well as the lamp voltage and power. From the effects of the applied current on the generated luminance, three starting scenarios are attempted to accelerate the starting transient stage. Experimental evidence shows that the starting time can be effectively shortened by increasing the lamp current during glow-to-arc and warm-up stages. A short interval of over-power operation during the warm-up stage enables the lamp to further enhance the producing of luminance quickly, and hence greatly reduce the starting transient period. According to the starting transient characteristics of metal halide lamps, an identification strategy is figured out to recognize three small-wattage metal halide lamps rated at powers of 20-W, 35-W and 70-W from three world-wide prominent brands, GE, OSRAM and PHILIPS. An electronic ballast is designed to drive the metal halide lamps with the multi-stage constant-power starting scenario. Experimental results evidence that the electronic ballast with the proposed identification strategy can recognize three lamps¡¦ rated powers correctly during the starting transition, and drive the lamp to its rated power before entering the steady-state.

The operating characteristics of metal halide lamps are investigated, including acoustic resonance, spectral energy, and luminous efficacy. To operate metal halide lamps at intended conditions, two test sophisticated ballast circuits are built to drive the lamps with sine-wave current and square-wave current, respectively. One ballast employs the series resonant inverter to output sinusoidal lamp current over a high-frequency range from 20 kHz to 300 kHz. The other makes use of the full-bridge inverter to drive the lamps with square-wave current from 50 Hz up to 300 kHz. For both test circuits, the operating frequency and the magnitude of the lamp current can be controlled independently. On the other hand, the lamp power is adjusted by regulating the DC-link power. Several conclusions are drawn from experimental results: (1) Little difference is found between the lighting spectra of a lamp when driven by sinusoidal current and square-wave current. (2) Luminous efficiency deteriorates as the operating frequency increases. The deterioration is more significant at lower frequencies. (3) Luminous efficiency decreases considerably as the lamp power is reduced. (4) Arc instability from acoustic resonance is highly related to the waveform of the lamp current. The investigated results give better understanding on the steady state operation of metal halide lamps and provide useful information for the design of the electronic ballasts.

The metal halide lamp has become an attractive lighting source because of its compact size, good color rendering, long lamp life, and high luminous efficacy. As a member of high-intensity discharge lamps, it has a negative incremental resistance, which claims the necessity of a ballast circuitry. Similar to other gas discharge lamps, the operating performance can be further improved when driven by a high-frequency electronic ballast. However, there are some obstacles in ballasting the metal halide lamp with the high-frequency inverter. For a cold lamp, an ignition voltage up to several kVs is required for breaking down the electrodes during starting period. The breakdown voltage and the equivalent lamp resistance may vary from time to time and lamp to lamp, and is sensitive to the used time. Furthermore, the ignition voltage for restarting a hot lamp can be ten times that for a cold lamp. On the other hand, the lamp driven by a high-frequency electronic ballast may suffer from acoustic resonance. All these make it difficult in the design of an electronic ballast, especially for the applications with hot restarting. In this dissertation, the operating characteristics for both starting transient and steady-state of the metal halide lamp are first investigated. Then, a simple method by measuring the lamp voltage is proposed to detect the happening of acoustic resonance. Based on the investigated results, several electronic ballasts are designed for driving metal halide lamps with capabilities of wide input voltage range, high input power factor, hot restarting, fast transition. In addition, an inverter circuit is configured for ballasting multiple lamps. A buck-boost power-factor-correction circuit is integrated into the load resonant inverter to achieve a high power factor, fast transition, and constant power operation. The extremely high ignition voltage for hot restarting is generated by an auxiliary ignitor. The electronic ballast is precisely operated at the specific frequency at which acoustic resonance will not occur. In addition to these features, a protection circuit is included to prevent from high voltage and/or current stresses on circuit components in case that the lamp fails to be started up or comes to the end of its life-time. For the ballast with multiple lamps, the load circuits with abnormal lamps can be isolated from the others which are under normal operation. Prototypes of the proposed circuits are built and tested. Experimental results present the satisfactory performances.

The operating characteristics of small-wattage metal halide lamps (35W, 70W, and 150W) are investigated. Included are acoustic resonance, luminous efficacy, and electrical characteristics at steady state. A laboratory electronic ballast is built to operate metal halide lamps with square-wave currents in a frequency range from 50 Hz up to 50 kHz. The operating frequency, amplitude and dead-time can be adjusted independently. Experimental results show that the luminous efficiency decreases slightly as the operating frequency increases but deteriorates considerably as the lamp power is reduced. By examining the acoustic resonance spectra, it is found that the lamp arc instability is highly related to the dead-time of the inverter. The investigated results provide useful information for the design of the electronic ballasts.

Halide Edib positioned herself as a main agent and figure of the Turkish nationalist movement, as both visionary and defender of her nation. Contributing to the evolving discourse on what it meant to be Turkish; Edib placed the family at the center of the state and identified women as state-builders. Through her interpretation of Turkish nationalism, I argue that Edib obscured the division between the public and private realm and classified women as agents in the creation of the Republic. I further contend that by doing this she contributed to the legitimization of Turkey on an international scale. This thesis focuses on the speeches Halide Edib delivered at the university Jamia Millia Islamia in New Delhi in 1935. These particular speeches are significant because they work towards a legitimization of Turkey, still in its infancy, as a nation, by addressing the "woman question." Halide Edib's view of a "new nation" and a "new woman" articulated in these speeches challenged contemporary views on women in a society at a political and cultural crossroads, overwhelmingly dominated by men.The power dynamics within the family and society at large are nuanced by Halide Edib's understanding of Turkish women's part in the national process during the formative years of the Turkish Republic. She depicted women as agents of nationalism and creators of the state. In doing this, she challenged both the ideological and applied position of women in the private realm, through her own discursive understanding of nationalism. Edib's definition of nationalism included the tenets of gender relations, family, and Islam and described each as a necessary component of a successful state.

This thesis is based on experimental results from measurements on methyl halides at a photon energy corresponding to the He IIβ emission line. Double ionization processes involving the valence electrons of the molecules CH3F, CH3Cl and CH3I are studied by means of a magnetic bottle TOF-PEPECO spectrometer. Resulting double ionization data of these molecules suggest that mainly direct double photoionization is observed as a continuous energy sharing between the ejected electron pairs. As a mean to further understand the double ionization processes, a "rule of thumb", for double ionization in molecules, is applied to the data presented in the double ionization spectra. This is done in order to quantify the effective distance between the two vacancies created in the dications. It is found that the distance between the vacancies may be related to the bond distance between the carbon and halogen atoms. Further investigations call for quantum chemical calculations to scrutinize this hypothesis. / Det här examensarbetet är baserat på experimentella fotojonisations studier av metyl halider vid en fotonenergi motsvarande He IIβ emissionslinjen. Valenselektronerna i dubbeljonisations processerna för CH3F, CH3Cl och CH3I har studerats under användning av en så-kallad magnetisk flask TOF-PEPECO spektrometer. Resultaten av dessa mätningar visar att mestadels direkt dubbeljonisation processer före- kommer, där elektronerna delar kontinuerligt på energin som friges vid jonisationen. Den dubbla jonisa- tions processen är ytterligare studerad genom att tillämpa en tumregel för dubbeljonisation i molekyler, vilket ger en indikation av hur stort avståndet är mellan de två vakanserna som skapades när molekylerna joniserade. Resultaten från tumregeln visar att avståndet mellan vakanserna kan vara relaterade till bind- ningsavståndet mellan kol-atomen och halogen-atomen, i respektive metyl halogen. För att ytterligare bekräfta dubbeljonisations processerna i dessa molekyler, krävs kvantmekaniska beräkningar.