Master of Science / Department of Mechanical and Nuclear Engineering / Kirby S. Chapman / Oxides of nitrogen (NOx), carbon monoxide (CO) and other combustion by-products of gas turbines have long been identified as harmful atmospheric pollutants to the environment and humans. Various government agencies place restrictions on emissions and often require some sort of emissions monitoring even for new low emission gas turbines. Predicting actual emissions from operating parameters that affect the formation of pollutants, called parametric emissions monitoring system (PEMS), has potential economic advantages compared to a continuous emissions monitoring system (CEMS). The problem is that a simple applicable PEMS does not exist. During this study, a gas turbine combustor model applying first engineering principles was developed to predict the emission formation of NOx and CO in a gas turbine. The model is based on a lean-premixed combustor with a main and pilot burner including the function of a bleeding air valve. The model relies on ambient condition and load. The load is expressed as a percentage of the target speed of the gas producer turbine. Air flow and fuel flow for the main and pilot burner are calculated by the model based on the load through a set of measured input data for a specific gas turbine. To find the combustion temperature characteristics, the combustor is divided into several zones. The temperature for each zone is calculated by applying an energy balance. To predict NOx and CO, several correlations explored by various researchers are used and compared against each other, using the calculated temperatures, pressures and equivalence ratios. A comparison between collected emissions examples from a turbine test cell data spreadsheet and predicted emissions by the developed model under the same conditions show a highly accurate match for NOx emission at any load. Because of the high variation of CO at part load, the model predictions only match the CO data set at full load.

Proton-Exchange Membrane (PEM) fuel cells are extremely attractive for replacing internal combustion engines in the next generation of automobiles. However, two major technical challenges remain to be resolved before PEM fuel cells become commercially successful. The first issue is that CO, produced in trace amounts in fuel reformer, severely limits the performance of the conventional platinum-based PEM fuel cell. A possible solution to the CO poisoning is higher temperature operation, as the CO adsorption and oxidation overpotential decrease considerably with increasing temperature. However, the process temperature is limited in atmospheric fuel cells because water is critical for high conductivity in the standard PEM. An increase in operating pressure allows higher temperature operation, although at the expense of parasitic power for the compressor. Further the conventional PEM, Nafion? is limited to 120°C due to it's low glass transition temperature. Thus, the design of higher temperature PEMs with stable performance under low relative humidity (RH) conditions is considered based on a proton transport model for the PEM and a fuel cell model that have been developed. These predictive models capture the significant aspects of the experimental results with a minimum number of fitted parameters and provides insight into the design of higher temperature PEMs operating at low RH. The design of an efficacious high temperature, low RH, PEM was based on enhancing the acidity and water sorption properties of a conventional PEM by impregnating it with a solid superacid. A systematic investigation of the composite Nafion?inorganic PEMs comprising experiments involving water uptake, ion-exchange capacity (IEC), conductivity and fuel cell polarization is presented in the work. The most promising composite is the nano-structured ZrO2/Nafion?PEM which exhibits an increase in the IEC, a 40% increase in water sorbed and a resulting 24% conductivity enhancement vs. unmodified Nafion?112 at 120°C and at RH < 40%.

Thomas Mofolo’s novel Chaka was a key contributor to Shaka’s mythical status. This thesis attempts to demonstrate the significance of this work in light of the author’s intellectual education and development by the Paris Evangelical Mission Society in Lesotho and the subsequent exploitation of the novel by Léopold Sédar Senghor. In the figure of Shaka, whom Senghor posed as an intellectual challenge to the imperial cultural assumptions of the colonising powers, the Senegalese author created one of Négritude’s most powerful symbols. Following Senghor, a succession of Francophone African versions of Mofolo’s story imbued the Zulu king with each author’s cultural and political idiosyncrasies. These versions offered entirely new texts, which performed the simultaneous acts of deculturation and neoculturation of Mofolo’s novel and Shaka/Chaka’s life. Traditionally, Anglophone and Francophone African literary cultures have been treated as separate intellectual spheres. This thesis seeks to understand the dialogue between them, and examines the evolving narrative of their cultural exchanges through the ‘transculturation’ of Mofolo’s Chaka.

Det här projektet handlar om att utveckla en metod för real driving emission (RDE). RDE är ett komplement till Worldwide Light Duty Test Procedure (WLTP) som kommer att ersätta New European Driving Cycle (NEDC). Dessa cykler och metoder används för att mäta personbilars avgaser. Huvudanledningen till varför NEDC ska bytas ut är för att körcyklerna inte längre är realistiska och reflekterar inte hur en bil presterar egentligen. Detta har lett till att bilar har högre bränsleförbrukning och högre avgasutsläpp när dom körs i trafiken jämfört med resultaten från NEDC.Metoden utvecklades genom hänvisningar till den officiella WLTP rapporten. Tillsammans med Vehicle Emission gruppen från AVL fastställdes en komplett steg för steg metod.Utrustningen som användes förseddes av AVL och flera tester av varje steg av metoden genomfördes för att förfina metoden så mycket som möjligt. Bilen som användes var en SAAB 9-5 2.0l bensin.Resultaten visade att både bilen och testet inte mötte kriterierna för RDE och godkändes inte av programmet som användes för att utvärdera testet. Detta var delvis för att kriterierna för RDE är strikta och delvis för att ingen pre och post test genomfördes eftersom det tar mycket tid för att dom testerna ska bli godkända.I överlag ger WLTP och RDE potentiella bilköpare en bättre detaljerad sammanfattning av hur bra bilen presterar i trafiken jämfört med NEDC. / This project is about developing a method for real driving emission (RDE). RDE is a complement to Worldwide Light Duty Test Procedure (WLTP) which will replace the New European Driving Cycle (NEDC). These cycles and procedures are used for measuring emissions for light duty vehicles. The main reason why NEDC is being replaced is because the driving cycles does not reflect how vehicles are normally driven. This has resulted in vehicles having higher fuel consumption and emitting more poisonous gases when driven on actual roads compared to the results from the NEDC.The method was developed by referring to the laws of the official WLTP report written by EU. Together with the Vehicle Emissions team at AVL a complete step by step method was established.All the equipment and instruments were provided by AVL and several tests of each step of the method was made to perfect the method as much as possible. The vehicle that was used was a 2005 SAAB 9-5 2.0l petrol.The results displayed that the car and the test did not meet the criteria for RDE and was not passed by the evaluating software. This was partly because the driving criteria for RDE are strict and can be difficult to achieve and partly because no pre and post test was made since it can take several tries before those tests are passed.Overall, WLTP and RDE give buyers a more detailed and better conclusion of how a car performs on the road compared to NEDC.

A Portable Emissions Measurement System (PEMS) is widely used for analysing the emissions of a vehicle. However, the PEMS is quite cumbersome and time-consuming to use for vehicle testing. This thesis investigates the possibilities of a Smart Emissions Measurement System (SEMS) and how it correlates to the more advanced PEMS. The second factor is of a shortened drive cycle, and how it is compared to the legislated drive cycle. The main hypothesis of this thesis was that a shortened drive cycle with the SEMS equipment should be able to predict the outcome of a full Real Driving Emissions (RDE) test with PEMS equipment with a statistical significance that is large enough to prove the SEMS to be a useful tool. The experiment was performed with a PEMS in parallel with a SEMS on both a shortened and a legislated drive cycle. The study concludes that the SEMS is showing promising results as to how well an RDE test can be predicted, and it would be a useful resource to increase testing on vehicles, both on a shortened and a legislated route. However, as the emissions of light-duty vehicles get smaller, they also get harder to measure with accuracy. This will always be a problem for the SEMS equipment, and even more on a shortened route. As a future application for light-duty vehicles, this might not be the perfect system due to many inaccuracies, but there are many other applications where SEMS could be useful with enough precision, such as heavier and older vehicles. / Portable Emissions Measurement System (PEMS) används i stor utsträckning för att analysera utsläpp av fordon. PEMS är dock ganska besvärligt och tidskrävande att använda vid fordonstestning. Det här examensarbetet undersöker möjligheterna med Smart Emissions Measurement System (SEMS) och hur det korrelerar med PEMS. Den andra faktorn som undersöks är en förkortad körcykel och hur den jämförs med den lagstadgade körcykeln. Huvudhypotesen i det här examensarbetet var att en förkortad körcykel med SEMS bör kunna förutsäga resultatet av ett fullständigt Real Driving Emissions (RDE)-test med PEMS med en tillräckligt stor statistisk signifikans för att visa att SEMS är ett användbart verktyg. Studien utfördes med PEMS parallellt monterat med SEMS på både en förkortad och en lagstadgad körcykel. Studien drar slutsatsen att SEMS visar lovande resultat för hur väl ett RDE-test kan förutsägas, och det skulle vara en användbar resurs för att öka testningen av fordon, både på en förkortad och en lagstadgad körcykel. Eftersom utsläppen från lätta fordon blir allt lägre, blir de även svårare att mäta med noggrannhet. Det kommer alltid att vara ett problem för SEMS, och särskilt på en förkortad rutt. Som en framtida applikation för lätta fordon kanske SEMS inte är det perfekta systemet på grund av att det inte är särskilt precist, men det finns många andra applikationer där SEMS kan vara användbart och där det har tillräcklig precision, så som för tyngre och äldre fordon.

Master of Science / Department of Mechanical and Nuclear Engineering / Kirby S. Chapman / The increased emissions monitoring requirements of industrial gas turbines have created a demand for less expensive emissions monitoring systems. Typically, emissions monitoring is performed with a Continuous Emissions Monitoring System (CEMS), which monitors emissions by direct sampling of the exhaust gas. An alternative to a CEMS is a system which predicts emissions using easily measured operating parameters. This system is referred to as a Parametric Emissions Monitoring System (PEMS). A review of the literature indicates there is no globally applicable PEMS. Because of this, a PEMS that is applicable to a variety of gas turbine manufacturers and models is desired. The research presented herein includes a literature review of NOx reduction techniques, NOx production mechanisms, current PEMS research, and combustor modeling. Based on this preliminary research, a combustor model based on first-engineering principles was developed to describe the NOx formation process and relate NOx emissions to combustion turbine operating parameters. A review of available literature indicates that lean-premixed combustion is the most widely-used NOx reduction design strategy, so the model is based on this type of combustion system. A review of the NOx formation processes revealed four well-recognized NOx formation mechanisms: the Zeldovich, prompt, nitrous oxide, and fuel-bound nitrogen mechanisms. In lean-premixed combustion, the Zeldovich and nitrous oxide mechanisms dominate the NOx formation. This research focuses on combustion modeling including the Zeldovich mechanism for NOx formation. The combustor model is based on the Siemens SGT-200 combustion turbine and consists of a series of well-stirred reactors. Results show that the calculated NOx is on the same order of magnitude, but less than the NOx measured in field tests. These results are expected because the NOx calculation was based only on the Zeldovich mechanism, and the literature shows that significant NOx is formed through the nitrous oxide mechanism. The model also shows appropriate trends of NOx with respect to various operating parameters including equivalence ratio, ambient temperature, humidity, and atmospheric pressure. Model refinements are suggested with the ultimate goal being integration of the model into a PEMS.

"Polyelectrolyte multilayer (PEM) thin films prepared via the Layer-by-Layer (LbL) deposition technique are of special interest in this research. The purpose of this study is to replace current mechanical closure systems, based on hook-and-loop type fasteners (i.e. Velcro), with PEM thin film systems. The technique is simple, cheap, versatile and environmental friendly; as a consequence a variety of thin films can be easily fabricated. By proposing PEMs as non-mechanical and nanoscopic molecular closures, we aim to obtain hermetic sealing, good adhesive strength, and peel off ease. Atomic force microscopy (AFM) and colloidal probe techniques were used to characterize the morphology, roughness and adhesive properties of PEMs. AFM measurements were conducted in air, necessarily requiring careful control of ambient humidity. PEMs were formed by consecutive deposition of polyanions and polycations on a charged polyethylene terephthalate (PET) solid surface, the result of which was stable nanostructured films. By systemically varying the parameters of PEM build-up process: different combinations of polyelectrolytes, different numbers of bilayers (polyanion/polycation pairs), and miscellaneous types and concentrations of salts (NaCl, NaBr and NaF salts at 0.5 M and 1.0 M concentrations), the adhesion and morphology of PEMs were thoroughly investigated. The PEM thin films specifically investigated include poly(ethyleneimine) (PEI), poly(styrene sulfonate) (PSS), poly(allylamine hydrochloride) (PAH), poly(acrylic acid) (PAA), and poly(diallydimethylammonium chloride) (PDADMAC). Silica colloidal probes were utilized in the investigation, some of which were functionalized with COOH and/or coated with PEI-PSS. Silica colloidal probes were used in order to quantify interaction forces on the PEMs. A functionalized silica colloidal probe (a probe with COOH surface chemistry) and a silica colloidal probe coated with PEI-PSS were used to simulate PEM-PEM interactions. The results suggest that adhesion in the PEMs depend on the number of layers, the salt concentration and the salt type used during the build-up process, the environmental conditions where the adhesion force measurements were made, and the choice of probe. "

Fundação de Amparo a Pesquisa do Estado de São Paulo / The reverse transcription polymerase chain reaction (RT-PCR) of turkey astrovirus (TAstV) capsid and polymerase gene was applied in the bursa of Fabricius (BF), thymus (TH), spleen (SP) and cloacal swabs (CS) from young poults with PEMS (Poult Enteritis Mortality Syndrome). The histological lesions were atrophy, lymphoid depletion, cellular infiltration and necrosis of BF, TH and SP, respectively. The RT-PCR reactions were positive in all of 100 CS, 7 out of 10 of BF, 10 out of 20 TH and SP, respectively, for the polymerase gene of TAstV-2. Five out of 10 TH and SP samples, considered as negative by RT-PCR, were positive when specific primers designed to the TAstV-2 capsid gene were applied. Finally, this is the first description of turkey astrovirus infection presenting PEMS in Latin America. / O Astrovírus dos Perus Tipo 2 (TAstV-2) é agente etiológico de uma doença emergente em perus, a Poult Enteritis Mortality Syndrome (PEMS), caracterizada por enterite severa, elevados índices de mortalidade, atrofia linfóide e imunossupressão em aves jovens, sendo responsável por sérios prejuízos financeiros à indústria avícola dos Estados Unidos. No Brasil, há necessidade de conhecimento sobre a ocorrência desses vírus nas diarréias das aves, sendo esse, um passo fundamental para o estabelecimento de medidas profiláticas específicas e para a exportação de produtos avícolas dentro das condições de sanidade. Este estudo teve por objetivos detectar TAstV, pela técnica de RT-PCR dirigida aos genes codificadores da polimerase e capsídeo viral, em perus jovens de 30 a 45 dias de idade com quadro clínico de diarréia severa, imunossupressão, baixo desempenho zootécnico e mortalidade, caracterizar alterações histopatológicas em bursa de Fabrícius (BF), timo (T) e baço (B) e, por fim, comparar os resultados obtidos com os dados de literatura. O TAstV-2 foi detectado em todas amostras de swabs cloacais (SC, n=100), 7 amostras de bursa de Fabrícius (BF, n=10) e em 10 amostras de timo (T, n=20) e baço (B, n=20). De 10 amostras de timo e baço negativas na primeira análise de RT-PCR, 5 foram positivas com o uso de primers específicos para o gene do capsídeo do TAstV-2. Os exames histológicos revelaram ocorrência de atrofia, depleção linfóide, infiltração celular e necrose da BF, T e B, respectivamente. Esses resultados representam a primeira descrição do TAstV-2 circulante em lotes comerciais de perus na América Latina. / Mestre em Genética e Bioquímica

Layer-by-layer assembly of polyelectrolytes is a simple technique based on the self-assembly of polycations and polyanions mainly by electrostatic interactions, which has gained considerable scientific interest for its versatility of applications. Ease of fabrication process, inexpensive approach and use to coat surfaces with various geometries prompts the researchers to select this technique not only for the surface modification applications but also to study the processes which exploit the 3D matrix properties of polyelectrolyte multilayer films (PEMs). Recent advances have been made where PEMs coatings have been utilized for their bio-applications like drug delivery and in tissue engineering for modifying the biomaterial's surfaces. In the field of drug delivery and tissue engineering the location and availability of the constituent molecules is very important, which is defined by their ability to diffuse through the encapsulating material or reservoir. So the main objective of this thesis is to understand the transport of molecules in ultrathin Polyelectrolyte Multilayer Films in lateral as well as transverse direction to the substrate. To study this transport behaviour in PEMs, we have employed various strategies which can enhance or suppress the diffusivity across PEMs. Thus, understanding the diffusion at nanoscale resolution will lead us to design better host materials for loading of drugs and growth factors for various biomedical applications.