Die vorliegende Dissertation beschäftigt sich mit der Synthese und Charakterisierung drei verschiedener Typen chiraler Phosphinoferrocene sowie deren Anwendung in der Palladiumkatalysierten Suzuki-Miyaura-Reaktion. Der Schwerpunkt liegt dabei auf Untersuchungen zur Synthese räumlich gehinderter Biaryle sowie auf atropselektiven Biarylkupplungen. Über eine Ullmann-artige Kupplung von Iodferrocen mit sekundären Alkoholen wurden zunächst chirale Ferrocenylalkylether synthetisiert, die mit Hilfe dirigierter Lithiierungen in 1,1'-disubstituierte Phosphinoferrocene der Art Fe( 5-C5H4OR)( 5-C5H4-C6H4-2-PR'2) sowie planar-chirale 1,2,1'-trisubstituierte Ferrocene des Typs Fe( 5-C5H3-1-PPh2-2-OR)( 5-C5H4SiMe3) überführt werden konnten. Erstere eignen sich für die Umsetzung räumlich gehinderter Arylhalogenide in der Suzuki-Miyaura-Reaktion, wobei die katalytische Produktivität mit sinkendem Tolman Kegelwinkel der Phosphine steigt. Darüber hinaus ist es möglich, Kupplungsreaktionen zwischen nicht aktivierten Bromaromaten und Phenylboronaäure bei ultraniedriger Katalysatorbeladung (1 ppm) durchzuführen. Die 1,2-P,O-substituierten Ferrocene erlauben die Synthese tri-ortho-substituierter Biaryle. Dabei zeigte sich, dass die Enantioselektivität der Umsetzung hauptsächlich durch die planare Chiralität des Ferrocens und nicht durch den chiralen Alkoxysubstituenten bestimmt wird. Darauf aufbauend wurde eine Serie verschieden substituierter planar-chiraler Phosphinoalkenylferrocene der Art Fe( 5-C5H3-2-PR'2-(E)-CH=CHR)( 5-C5H5) synthetisiert. Die elektrochemische Untersuchung dieser Verbindungen zeigte, dass die -Donoreigenschaften des Phosphins durch die elektronischen Eigenschaften des alkenylgebundenen Substituenten R nicht verändert werden. Dies erlaubt die unabhängige Variation der -Donor-/ -Akzeptoreigenschaften des Phosphins und des Alkens. Abschließend wurde ein Vertreter der Phosphinoalkenylferrocene in der Synthese tri- und tetra-ortho-substituierter Biaryle sowie in atropselektiven Biarylkupplungen eingesetzt. Die Leistungsfähigkeit des Katalysators in der Suzuki-Miyaura-Reaktion wurde durch die Variation der Substratpalette untersucht.

[pt] Este trabalho apresenta uma estratégia de modelagem aberta e extensível, desenvolvida em Python, para a criação de modelos de subdivisões planares. A estratégia se dá na forma de uma biblioteca de modelagem geométrica, denominada HETOOL, desenvolvida no trabalho e de uso genérico, baseada na conhecida e consagrada estrutura de dados topológica Half-Edge. Além de considerar os aspectos topológicos e geométricos da modelagem, a estratégia também permite a configuração pelo usuário final dos atributos de simulação. Essas características, somadas à disponibilização do código fonte, conferem um caráter útil e relevante para o desenvolvimento de ferramentas educacionais para modelagem em mecânica computacional. Para demonstrar a aplicabilidade da estratégia proposta, foi desenvolvido um aplicativo, denominado de Finite Element Method Educational Computer Program (FEMEP), que permite a criação de modelos bidimensionais de elementos finitos, com geração de malhas por região, para diversos tipos de simulação de mecânica computacional. O pacote desenvolvido apresenta uma modelagem iterativa e dinâmica que realiza a interseção automática entres os elementos geométricos modelados. O HETOOL oferece várias funcionalidades e facilidades ao usuário, permitindo o uso do pacote mesmo sem o usuário ter conhecimento sobre os conceitos topológicos envolvidos na implementação dessa estrutura de dados. O pacote possibilita a criação e configuração atributos de forma simples e rápida a partir de um arquivo no formato JSON. Essa versatilidade na criação atributos permite a aplicação deste pacote na resolução de vários problemas presentes na engenharia e em outras áreas do meio científico. / [en] This work presents an open and extensible modeling strategy, developed in Python, for creating planar subdivision models. The strategy takes the form of a geometric modeling library called HETOOL, developed in the work and of general use, based on the well-known and renowned Half-Edge topological data structure. In addition to considering the topological and geometric aspects of the modeling, a strategy also allows for an end-user configuration of simulation attributes. These characteristics, added to the availability of the source code, provide a useful and relevant tool for the development of educational tools for modeling computational mechanics. To demonstrate the applicability of the proposed strategy, an application was developed, called the Finite Element Method Educational Computer Program (FEMEP), which allows the creation of two-dimensional finite element models, with mesh generation per region, for various types of mechanics simulation computational. The developed package presents iterative and dynamic modeling that performs an automatic intersection between the modeled geometric elements. HETOOL offers several functions and facilities to the user, allowing the use of the package even without the user having knowledge about the topological concepts involved in the implementation of this data structure. The package makes it possible to create and configure attributes simply and quickly from a file in JSON format. This versatility in creating attributes allows the application of this package to solve several problems present in engineering and in other areas of the scientific environment.

Since the 1950s the jet aeroacoustics community has been involved in predicting and measuring the noise distribution in jets. In this work, cylindrical and planar Fourier near-field acoustical holography are used to investigate radiation from a full-scale, installed jet engine. Practical problems involving measurement aperture and the highly directional nature of the source are addressed. Insights from numerical simulations reveal usable reconstruction regions. A comparison of cylindrical and planar NAH for the respective measurement apertures shows cylindrical NAH outperforms planar NAH on reconstructions both towards and away from the source.

A simple and novel dual-CP printed antenna is modelled and measured. The patch antennais small and achieves a low axial ratio without quadrature feeding. The measured pattern showsaxial ratio pattern squinting over frequency. Possible methods of improving the individual element are discussed, as well as an array technique for improving the axial ratio bandwidth. Three endfire printed antenna structures are designed, analyzed, and compared. The comparison includes an analysis of costs of production for the antenna structures in addition to their performance parameters. This analysis concludes that cost of materials primarily reduces the size of antennas for a given gain and bandwidth. An antenna stucture with an annular beam pattern for down-looking navigational radar is proposed. The antenna uses sub-wavelength grating techniques from optics to achieve a highly directive planar reflector which is used as a ground plane for a monopole. A fan-beam array element is fabricated for use in a digitally steered receive array for obstacle avoidance radar. The steered beam pattern is observed. The element-dependent phase shifts for a homodyned signal in particular are explored as to their impact on beam steering.

No description available.

<p dir="ltr">Burst-mode lasers and burst-mode optical parametric oscillators (OPOs) are applied and developed for planar laser induced fluorescence (PLIF) measurements of key species for high-speed combustion measurements. OH-PLIF in the rotating detonation engine was performed for the first time at wave structure visualization in two different planes and was 10 times faster than any other burst mode OH-PLIF measurements at the time. The same system was used to perform another OH-PLIF experiment at 1 MHz for ~200 pulses to compare key features of the detonation wave structure with computational fluid dynamic simulations and a fundamental detonation tube experiment. The system was also used for seedless velocity measurements in the exhaust by tracking a pocket of OH with a technique called FLASH. A similar OPO was built, aligned, and tuned to perform 1 MHz NO PLIF in a Mach 10 hypersonic tunnel to visualize second mode instabilities and calculate the frequency in the boundary layer transition of a 7-degree cone. A high-efficiency OPO was developed and characterized utilizing the KTP crystal to provide narrow bandwidth pulses for the fluorescence of multiple species. The OPO was pumped at repetition rates up to 1 MHz and was calculated to have a 1.9% UV efficiency from the fundamental 1064 nm output. This is 3 – 5 times increase in efficiency from previous custom and commercial built OPOs. The OPO was applied to the RDC for OH PLIF in the combustor channel and NO PLIF for injector dynamics and response studies. Lastly, a burst-mode laser was used to perform LII on the post detonation blast flow field to measure explosively generated soot. The data was taken at 1 MHz and compared and corrected with a separate set of experiments and computational simulations.</p>

When an atomic nucleus undergoes fission, two fragments with different mass and kinetic energy are emitted. The highly unstable fission fragments (FFs) evaporate prompt neutrons soon after the nucleus splits. A precise measurement of both, the mass yield distribution of the FFs and the average prompt neutron emission, $\bar{\nu}$, is important not only for current nuclear technologies but also for the development of future technologies such as Generation IV nuclear power plants. Moreover, the experimental determination of the mass yield distributions, both pre- and post-neutron emission, is valuable for testing fission models. Additionally, a precise measurement of the average neutron multiplicity as a function of the FFs mass, <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?$%5Cbar%7B%5Cnu%7D(A)$" data-classname="equation" data-title="" />, is crucial in the understanding of how the excitation energy is shared between nascent FFs.  The VElocity foR DIrect particle identification spectrometer (VERDI) is designed to achieve pre- and post-fission mass distributions with resolutions between 1-2 u. VERDI is a double-energy double-velocity instrument that consists of two arms. On each arm is operated one Microchannel Plate detector (MCP) for the collection of the FFs start time and up to 32 Passive Implanted Planar Silicon (PIPS) detectors for the stop time and energy detection of the FFs. However, challenges in the experimental measurements with VERDI arise due to the high degree of ionization (plasma) in the detector material from the interaction with the FFs. The plasma causes a delay in the charge carriers' migration for the signal start, known as the plasma delay time effect (PDT). Furthermore, the recombination of charge carriers in the plasma causes a shrinking in the signal's height, known as pulse height defect (PHD). This phenomenon leads to inaccuracies in the measurement of FFs mass distributions and increased systematic uncertainties.  Previous studies on PDT and PHD have shown varying behaviors across different detector types, which motivated dedicated studies in the type of PIPS detectors used in VERDI. An experimental campaign to characterize the PDT and PHD in PIPS detectors was conducted in the LOHENGRIN recoil separator, which is part of the ILL nuclear facility in Grenoble, France. Measurements of FFs in a range of masses between 80 u and 149 u, with energies between 20 MeV to 110 MeV, were taken to fully characterize six PIPS detectors. The resulting PDT and PHD values were 1 ns to 4 ns and 2 MeV to 10 MeV respectively. The PDT and PHD exhibited consistent energy and mass dependencies across the detectors, which enables the possibility of an event-by-event correction of VERDI data. In this thesis, the basis for discussing the results of the studies of the PDT and PHD effects will be presented.

The main objectives of this research are to investigate and design low profile antennas for mobile handsets applications using the balanced concept. These antennas are considered to cover a wide range of wireless standards such as: DCS (1710¿1880 MHz), PCS (1850¿1990 MHz), UMTS (1920¿2170 MHz), WLAN (2400¿2500 MHz and 5000 ¿ 5800 MHz) and UWB frequency bands. Various antennas are implemented based on built-in planar dipole with a folded arm structure. The performance of several designed antennas in terms of input return loss, radiation patterns, radiation efficiency and power gain are presented and several remarkable results are obtained. The measurements confirm the theoretical design concept and show reasonable agreement with computations. The stability performance of the proposed antenna is also evaluated by analysing the current distribution on the mobile phone ground plane. The specific absorption rate (SAR) performance of the antenna is also studied experimentally by measuring antenna near field exposure. The measurement results are correlated with the calculated ones. A new dual-band balanced antenna using coplanar waveguide structure is also proposed, discussed and tested; this is intended to eliminate the balanced feed network. The predicted and measured results show good agreement, confirming good impedance bandwidth characteristics and excellent dual-band performance. In addition, a hybrid method to model the human body interaction with a dual band balanced antenna structure covering the 2.4 GHz and 5.2 GHz bands is presented. Results for several test cases of antenna locations on the body are presented and discussed. The near and far fields were incorporated to provide a full understanding of the impact on human tissue. The cumulative distribution function of the radiation efficiency and absorbed power are also evaluated. / UK Engineering and Physical Sciences Research Council (EPSRC)

The rapidly growing demand for UWB as high data rates wireless communications technology, since the Federal Communications Commission (FCC) allocated the bandwidth of UWB from 3.1GHz to 10.6 GHz. Antenna also plays an essential role in UWB system. However, there are some difficulties in designing UWB antenna as compared to narrowband antenna. The primary requirement of UWB antennas is be able to operate over frequencies released by the FCC. Moreover, the satisfaction of radiation properties and good time domain performance over the entire frequency range are also necessary. In this thesis, designing and analysing printed crescent shape monopole antenna, Planar Inverted F-L Antenna (PIFLA) and Planar Inverted FF Antenna (PIFFA) are focused. A Planar Inverted FF Antenna (PIFFA) can be created to reduce the potential for interference between a UWB system and other communications protocols by using spiral slot. The antennas exhibits broadside directional pattern. The performances such as return loss, radiation pattern and current distribution of the UWB antennas are extensively investigated and carried out. All the results have been demonstrated using simulation and experimentally whereby all results satisfy the performance under - 10dB point in the bandwidth of UWB. In addition the miniaturization of MIMO/diversity Planar Inverted-F antenna (PIFA) which is suitable for pattern diversity in UWB applications is presented. This antenna assembly is formed by two identical PIFAs, a T-shaped decoupling structure which connects the two PIFAs and a finite ground plane with a total compact envelope dimension of 50 ¿ 90 ¿ 7.5mm3. The radiation performance of the proposed MIMO antenna was quite encouraging and provided an acceptable agreement between the computed and measured envelope correlation coefficient and channel capacity loss. / General Secretariat of Education and Scientific Research Libya

General Secretariat of Education and Scientific Research, Libya. / The only available copy is the print version kept in the J.B.Priestley Library for reference.