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This dissertation presents an empirical approach to identifying decisions for adapting cognitive radio parameters with no a priori knowledge of the environment. Cognitively inspired radios, attempt to combine observed metrics of system performance with artificial intelligence decision-making algorithms. Current architectures trend towards hybrid combinations of heuristics, such as genetic algorithms (GA) and experiential methods, such as case-based reasoning (CBR). A weakness in the GA is its reliance on limited mathematical models for estimating bit error rate, packet error rate, throughput, and signal-to-noise ratio. The CBR approach is similarly limited by its dependency on past experiences. Both methods have potential to suffer in environments not previously encountered. In contrast, the statistical methods identify performance estimation models based on exercising defined experimental designs. This represents an experiential decision-making process formed in the present rather than the past. There are three core contributions from this empirical framework: 1) it enables a new approach to decision making based on empirical estimation models of system performance, 2) it provides a systematic method for initializing cognitive engine configuration parameters, and 3) it facilitates deeper understanding of system behavior by quantifying parameter significance, and interaction effects. Ultimately, this understanding enables simplification of system models by identifying insignificant parameters. This dissertation defines an abstract framework that enables application of statistical approaches to cognitive radio systems regardless of its platform or application space. Specifically, it assesses factorial design of experiments and response surface methodology (RSM) to an over-the-air wireless radio link. Results are compared to a benchmark GA cognitive engine. The framework is then used for identifying software-defined radio initialization settings. Taguchi designs, a related statistical method, are implemented to identify initialization settings of a GA. / Ph. D.

Liquid waste discharged from industrial outfalls is categorized into two major classes based on their density. One type is the effluent that has a higher density than that of the ambient water body. In this case, the discharged effluent has a tendency to sink as a negatively buoyant jet. The second type is the effluent that has a lower density than that of the ambient water body and is hence defined as a (positively) buoyant jet that causes the effluent to rise. Negatively/Positively buoyant jets are found in various civil and environmental engineering projects: discharges of desalination plants, discharges of cooling water from nuclear power plants turbines, mixing chambers, etc. This thesis investigated the mixing and dispersion characteristics of such jets numerically. In this thesis, mixing behavior of these jets is studied using a finite volume model (OpenFOAM). Various turbulence models have been applied in the numerical model to assess the accuracy of turbulence models in predicting the effluent discharges in submerged outfalls. Four Linear Eddy Viscosity Models (LEVMs) are used in the positively buoyant wall jet model for discharging of heated waste including: standard k-ε, RNG k-ε, realizable k-ε and SST k-ω turbulence models. It was found that RNG k-ε, and realizable k-ε turbulence models performed better among the four models chosen. Then, in the next step, numerical simulations of 30˚ and 45˚ inclined dense turbulent jets in stationary ambient water have been conducted. These two angles are examined in this study due to lower terminal rise height for 30˚ and 45˚, which is very important for discharges of effluent in shallow waters compared to higher angles. Five Reynolds-Averaged Navier-Stokes (RANS) turbulence models are applied to evaluate the accuracy of CFD predictions. These models include two LEVMs: RNG k-ε, and realizable k-ε; one Nonlinear Eddy Viscosity Model (NLEVM): Nonlinear k-ε; and two Reynolds Stress Models (RSMs): LRR and Launder-Gibson. It has been observed that the LRR turbulence model as well as the realizable k-ε model predict the flow more accurately among the various turbulence models studied herein.

Pseudomonas aeruginosa is a ubiquitous, opportunistic pathogen that causes acute and chronic infections. Infection is typically initiated via motile and virulent strains. After exposure to stressors, acute infections make both genotypic and phenotypic switches to a chronic, sessile strain. This is due to intricate regulatory networks directing gene expression in response to stressors. One network, GacA/GacS, has been established to control virulence factors. The stringent response of bacteria is mediated by alarmones produced primarily by RelA which responds to starvation. To study the effect of the stringent response on the virulence switch. A series of experiments were run in both PAO1, a virulent strain, and PDO300, an acute strain, and RelA deletion mutants of each transcriptional fusions of GacA/GacA system were integrated in the wild-types and mutants. Alginate, swimming, twitching, and biofilm formation assays were performed on all. The preliminary data suggests that the stringent response influences the GacA/GacS system.

This thesis reports on the development of low-temperature processes for transition metal carbide and MAX-phase thin film growth. Magnetron sputtering and evaporation, far from thermodynamical equilibrium, have been utilised to engineer the properties of the films by physical and chemical control. Deposition of W, W2C and β-WC1-x films with controlled microstructure, from nanocrystalline to epitaxial, is shown in the W-C system down to 100 oC. W films with upto 20 at% C exhibited an extreme solid-solution hardening effect, with a nanoindentation hardness maximum of 35 GPa. Furthermore, the design of epitaxial ternary carbide films is demonstrated in the Ti1-xVxCy system in the form of controlled unit-cell parameters, strain-free films with a perfect match to the substrate, and ternary epitaxial gradient films. Moreover, phase stabilisation and pseudomorphic growth can be tuned in (Nb,Mo)C and (Ti,W)C films. The results obtained can be used for example to optimise electrical contacts in SiC high-power semiconductor devices. A large part of this thesis focuses on the deposition of MAX-phases. These compounds constitute a family of thermally stable nanolaminates with composition Mn+1AXn, n=1, 2 or 3, where M is an early transition metal, A is generally a group 13-14 element, and X is C or N. They show a combination of typical ceramic and metallic properties and are also machinable by virtue of the unique deformation behaviour observed only in laminates. So far, the MAX-phases have almost exclusively been prepared by high-temperature sintering and studied in bulk form. However, this thesis establishes a patented seed layer approach for successful MAX-phase thin film depositions down to 750 oC. For the first time, single-phase and epitaxial films of Ti3SiC2, Ti3AlC2 and Ti2AlC have been grown. The method has also been used to synthesise a new MAX-phase, Ti4SiC3. In addition, two previously unreported intergrown MAX-type structures are presented, Ti5Si2C3 and Ti7Si2C5. Combined theoretical and experimental results show the possibility to deposit films with very low bulk resistivity and designed mechanical properties. Furthermore, the demonstration of MAX-phase and carbide multilayer films paves the way for macrostructure engineering, for example, in coatings for low-friction or wear applications.

O aumento nos rejeitos industriais e a contínua produção de resíduos causam muitas preocupações no âmbito ambiental. Neste contexto, o descarte de pneus usados tem se tornado um grande problema por conta da pequena atenção que se dá à sua destinação final. Assim sendo, essa pesquisa propõe a produção de uma mistura polimérica com polipropileno (PP), a borracha de etileno-propileno-dieno (EPDM) e o pó de pneu (SRT). A Metodologia de Superfície de Resposta (MSR), coleção de técnicas estatísticas e matemáticas úteis para desenvolver, melhorar e optimizar processos, foi aplicada à investigação das misturas ternárias. Após o processamento adequado em extrusora de dupla rosca e a moldagem por injeção, as propriedades mecânicas de resistência à tração e resistência ao impacto foram determinadas e utilizadas como variáveis resposta. Ao mesmo tempo, a microscopia eletrônica de varredura (MEV) foi usada para a investigação da morfologia das diferentes misturas e melhor interpretação dos resultados. Com as ferramentas estatísticas específicas e um número mínimo de experimentos foi possível o desenvolvimento de modelos de superfícies de resposta e a otimização das concentrações dos diferentes componentes da mistura em função do desempenho mecânico e além disso com a modificação da granulometria conseguimos um aumento ainda mais significativo deste desempenho mecânico. / The increase in industrial waste and solid waste production cause many concerns in the environment. In this context, the disposal of used tires has become a major problem because of the little attention given to their final destination. Therefore, this research proposes the production of a polymer blend of polypropylene (PP), rubber of ethylene-propylene-diene (EPDM) and tire dust (SRT). The Response Surface Methodology (RSM), a collection of mathematical and statistical techniques useful for developing, improving and optimizing processes, was applied to the investigation of ternary mixtures. After proper processing on twin screw extrusion and injection molding, the mechanical properties of tensile and impact strength were determined and used as response variables. At the same time, scanning electron microscopy (SEM) was used to investigate the morphology of different blends and better interpretation of results. With specific statistical tools and a minimum number of experiments it was possible to develop models of response surfaces and the optimization of the concentrations of different components of the mixture depending on the mechanical performance and even with the change in particle size could increase even more significant this mechanical performance.

<p>This thesis reports on the development of low-temperature processes for transition metal carbide and MAX-phase thin film growth. Magnetron sputtering and evaporation, far from thermodynamical equilibrium, have been utilised to engineer the properties of the films by physical and chemical control. Deposition of W, W₂C and β-WC_1-x films with controlled microstructure, from nanocrystalline to epitaxial, is shown in the W-C system down to 100 ^oC. W films with upto 20 at% C exhibited an extreme solid-solution hardening effect, with a nanoindentation hardness maximum of 35 GPa. Furthermore, the design of epitaxial ternary carbide films is demonstrated in the Ti_1-xV_xC_y system in the form of controlled unit-cell parameters, strain-free films with a perfect match to the substrate, and ternary epitaxial gradient films. Moreover, phase stabilisation and pseudomorphic growth can be tuned in (Nb,Mo)C and (Ti,W)C films. The results obtained can be used for example to optimise electrical contacts in SiC high-power semiconductor devices. </p><p>A large part of this thesis focuses on the deposition of MAX-phases. These compounds constitute a family of thermally stable nanolaminates with composition M_n+1AX_n, n=1, 2 or 3, where M is an early transition metal, A is generally a group 13-14 element, and X is C or N. They show a combination of typical ceramic and metallic properties and are also machinable by virtue of the unique deformation behaviour observed only in laminates. So far, the MAX-phases have almost exclusively been prepared by high-temperature sintering and studied in bulk form. However, this thesis establishes a patented seed layer approach for successful MAX-phase thin film depositions down to 750 ^oC. For the first time, single-phase and epitaxial films of Ti₃SiC₂, Ti₃AlC₂ and Ti₂AlC have been grown. The method has also been used to synthesise a new MAX-phase, Ti₄SiC₃. In addition, two previously unreported intergrown MAX-type structures are presented, Ti₅Si₂C₃ and Ti₇Si₂C₅. Combined theoretical and experimental results show the possibility to deposit films with very low bulk resistivity and designed mechanical properties. Furthermore, the demonstration of MAX-phase and carbide multilayer films paves the way for macrostructure engineering, for example, in coatings for low-friction or wear applications.</p>

The first aim of this study is the development of extracellular recombinant therapeutic protease streptokinase producing Bacillus sp., and the second aim is to determine fermentation characteristics for streptokinase production. In this context, the signal (pre-) DNA sequence of B.licheniformis (DSM1969) extracellular serine alkaline protease enzyme gene (subC: Acc. No. X03341) was ligated to 5&rsquo / end of the streptokinase gene (skc: Acc. No. S46536) by SOE (Gene Splicing by Overlap Extension) method through PCR. The resulting hybrid gene pre(subC)::skc was cloned into the pUC19 plasmid. Then, the hybrid gene was sub-cloned to pMK4 plasmid which is an E. coli-Bacillus shuttle vector with high copy number and high stability. Recombinant plasmid pMK4::pre(subC)::skc was finally transferred into B. subtilis (npr- apr-) and B. licheniformis 749/C (ATCC 25972) species. Streptokinase production capacities of these two recombinant Bacillus species were compared. The highest production was observed in recombinant B. lichenifomis 749/C (ATCC 25972) strain in a defined medium which was optimized in terms of carbon and nitrogen sources by a statistical approach, namely Response Surface Methodology (RSM). RSM evaluated the streptokinase concentration as the response and the medium components as the independent variables. The highest recombinant streptokinase concentration was found as 0.0237 kgm-3 at glucose and (NH4)2HPO4 concentrations of 4.530 and 4.838 kgm-3 respectively. The fermentation and oxygen transfer characteristics of the streptokinase production were investigated in a 3 dm3 pilot scale batch bioreactor (Braun CT2-2) equipped with temperature, pH, foam, air inlet and agitation rate controls having a working volume of VR=1.65 dm3 using the production medium optimized for the recombinant B. lichenifomis 749/C (ATCC 25972) strain. Streptokinase and &amp / #946 / -lactamase activities, cell, glucose and organic acid concentrations, dissolved oxygen, pH, oxygen uptake rate, overall liquid phase mass transfer coefficient for oxygen, maintenance coefficient for oxygen, specific cell growth rate and yield coefficients were determined through the bioprocess. The bioprocess of recombinant streptokinase production was performed at uncontrolled pH of these bioreactor operation conditions: air inlet rate of Q0/VR=0.5 vvm, and the agitation rate of N=400min-1. The resulting streptokinase volumetric activity reached its maximum as 1.16 PUml-1 (0.0026 g/l streptokinase) at t=20 h.

Kitchen waste, which is collected in large amounts from cafeterias, restaurants, dining halls, food processing plants, and household kitchens, have become a valuable material for bioprocess engineering. Due to the high carbohydrate fraction, kitchen waste has great potential to be used as a potential substrate for ethanol production. Utilization of it as a raw material in ethanol fermentation would also contribute to reduction of costs. In the first part of this study, the effect of pretreatment method and enzymatic hydrolysis on glucose production was evaluated. Dry baker&rsquo / s yeast, Saccharomyces cerevisiae, was used in fermentation experiments conducted with and without fermentation medium at pH 4.5 and 30oC for 48 hours. Close values of glucose concentration were obtained from no pretreated and hot water treated samples. The fermentation results indicated that ethanol can be produced at similar concentrations in bioreactors with and without fermentation medium addition (p &gt / 0.05). Thus, it is concluded that use of kitchen wastes as is disposed and without fermentation medium in ethanol fermentation could lower the cost to a large extent. In the second part of this study, the effects of solid load, which is proportional to the glucose concentration (10% to 20% (w/w)), inoculum level of Saccharomyces cerevisiae (5% to 15% (v/v)), and fermentation time (48 to 96 h) on production of bioethanol from kitchen waste were studied using Response Surface Methodology (RSM). A three-factor Box Behnken design was used. Ethanol concentration was used as a response in the resulting experimental design. High Pressure Liquid Chromatography (HPLC) method was used to determine ethanol and glucose concentrations. The statistical analysis of the constructed model developed by RSM suggested that linear effects of solid load, inoculum level, and fermentation time and quadratic effects of inoculum level and fermentation time were all significant (p &lt / 0.05) on bioethanol production. The model was verified by additional runs, which were not present in the design matrix. It was found that the constructed model could be used to determine successfully the bioethanol concentration with &gt / 90% precision. An optimum ethanol concentration of 32.16 g/L was suggested by the model with 20% (w/w) solid load, 8.85% (v/v) inoculum level and 58.8 hours of fermentation. Further study is needed to evaluate the optimal fermentation conditions in a large scale fermentation

O aumento nos rejeitos industriais e a contínua produção de resíduos causam muitas preocupações no âmbito ambiental. Neste contexto, o descarte de pneus usados tem se tornado um grande problema por conta da pequena atenção que se dá à sua destinação final. Assim sendo, essa pesquisa propõe a produção de uma mistura polimérica com polipropileno (PP), a borracha de etileno-propileno-dieno (EPDM) e o pó de pneu (SRT). A Metodologia de Superfície de Resposta (MSR), coleção de técnicas estatísticas e matemáticas úteis para desenvolver, melhorar e optimizar processos, foi aplicada à investigação das misturas ternárias. Após o processamento adequado em extrusora de dupla rosca e a moldagem por injeção, as propriedades mecânicas de resistência à tração e resistência ao impacto foram determinadas e utilizadas como variáveis resposta. Ao mesmo tempo, a microscopia eletrônica de varredura (MEV) foi usada para a investigação da morfologia das diferentes misturas e melhor interpretação dos resultados. Com as ferramentas estatísticas específicas e um número mínimo de experimentos foi possível o desenvolvimento de modelos de superfícies de resposta e a otimização das concentrações dos diferentes componentes da mistura em função do desempenho mecânico e além disso com a modificação da granulometria conseguimos um aumento ainda mais significativo deste desempenho mecânico. / The increase in industrial waste and solid waste production cause many concerns in the environment. In this context, the disposal of used tires has become a major problem because of the little attention given to their final destination. Therefore, this research proposes the production of a polymer blend of polypropylene (PP), rubber of ethylene-propylene-diene (EPDM) and tire dust (SRT). The Response Surface Methodology (RSM), a collection of mathematical and statistical techniques useful for developing, improving and optimizing processes, was applied to the investigation of ternary mixtures. After proper processing on twin screw extrusion and injection molding, the mechanical properties of tensile and impact strength were determined and used as response variables. At the same time, scanning electron microscopy (SEM) was used to investigate the morphology of different blends and better interpretation of results. With specific statistical tools and a minimum number of experiments it was possible to develop models of response surfaces and the optimization of the concentrations of different components of the mixture depending on the mechanical performance and even with the change in particle size could increase even more significant this mechanical performance.