Submitted by Etelvina Domingos (etelvina.domingos@ufpe.br) on 2015-03-10T19:39:47Z No. of bitstreams: 2 VERSÃO FINAL DA TESE DE DOUTORADO DE RICARDO SCHNEIDER Correções Banca 24-02-12 as 19 30 (2).pdf: 6805434 bytes, checksum: 4e1a4cf9c9351d215edfb5bd590bc6b8 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-10T19:39:47Z (GMT). No. of bitstreams: 2 VERSÃO FINAL DA TESE DE DOUTORADO DE RICARDO SCHNEIDER Correções Banca 24-02-12 as 19 30 (2).pdf: 6805434 bytes, checksum: 4e1a4cf9c9351d215edfb5bd590bc6b8 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2012-01 / Foram desenvolvidos e estudados sistemas vítreos com a capacidade de formação de nanopartículas e filmes nanoestruturados, quando submetidos a tratamento térmico, para atuar como parte ativa de dispositivos. As composições dos sistemas desenvolvidos e avaliados mostraram-se adequadas para produção de fibras. O crescimento de nanofilmes foi monitorado em função das condições de tratamento térmico, em temperaturas características de cada sistema, através de microscopia de força atômica (AFM) e microscopia eletrônica de varredura (MEV). Um dos sistemas desenvolvidos no presente trabalho resultou em aplicação como parte ativa de dispositivos sensores de gás hidrogênio. As temperaturas características dos sistemas estudados foram determinadas por análise térmica e utilizadas em simulações dos eventos térmicos observados. As simulações foram realizadas com rotinas desenvolvidas no programa Wolfram Mathematica®, possibilitando caracterização dos mecanismos associados aos processos de cristalização. As amostras vítreas em forma de fibras puxadas a partir dos sistemas baseados em compostos de chumbo, GAPAgF e GAPAgO, dopadas com íons prata, foram obtidas pela fusão dos reagentes de partida em forno resistivo, seguidas pelo tratamento térmico em torno da temperatura de transição vítrea (Tg) para produzir o filme de prata nanoestruturado na superfície das fibras. Um terceiro sistema, baseado em fosfato (NaPONG), apresentou crescimento de filme nanoestruturado apenas quando submetido a tratamento térmico em atmosfera redutora, diferenciando substancialmente do mecanismo envolvido nos sistemas anteriores (GAPAgF e GAPAgO). O sistema NaPONG apresenta uma capacidade de dissolução de vários óxidos e compostos, e permitiu a dopagem deste sistema também com íons Ni2+ e a obtenção de nanopartículas de níquel. O crescimento do filme nanoestruturado nos sistemas de compostos de chumbo apresenta forte dependência com a temperatura necessária para o crescimento do filme. Tal dependência não é observada no sistema baseado em fosfato, o que permite a obtenção de filmes em temperaturas em torno de 340 °C, abaixo da Tg do sistema. O crescimento das nanopartículas foi monitorado por AFM em ambos os sistemas, em função do tempo de tratamento térmico. Detectou-se crescimento de nanoestruturas de prata com 50 nm em apenas um minuto e cinco minutos de tratamento térmico, para os sistemas GAPAgO e NaPONG, respectivamente. Quanto às características elétricas, o filme nanoestruturado, que se apresenta como não-condutor quando obtido nos sistemas baseados em chumbo, mostrou-se condutor no sistema fosfato, obtido com tratamento térmico de trinta minutos a 350 °C sob atmosfera de H2. Imagens de MEV mostram que a condutividade é obtida quando se estabelece o “contato” entre as nanopartículas que formam o filme, ultrapassando um limiar de percolação, formando um caminho ininterrupto pelo qual fluirá a corrente elétrica. Fibras do sistema fosfato com filme condutor foram aplicadas no desenvolvimento de dispositivos sensores de gás. O dispositivo obtido mostra sensibilidade ao gás hidrogênio e não aos gases oxigênio e nitrogênio. Os resultados indicam que o dispositivo desenvolvido pode atuar como sensor seletivo, com aplicações nas áreas de processos e segurança.

The role of histamine in chronic gastrointestinal diseases has been increasingly recognized in humans, but the role of histamine in the canine gastrointestinal tract has not been thoroughly investigated. The presence and distribution of all 4 histamine receptors (H1, H2, H3, and H4) in the stomach, duodenum, ileum, jejunum, and colon of healthy dogs were evaluated with a commonly employed immunohistochemistry technique using antibodies predicted to cross react with canine histamine receptors. All 4 histamine receptors were identified in the canine gastrointestinal tract, and differed in location and density within sections of the canine gastrointestinal tract. Antibody specificity was evaluated with Western blot. With the establishment of a method to study histamine receptors in the canine gastrointestinal tract, additional research to evaluate histamine receptors in dogs is warranted to further understand the pathophysiology and treatment of chronic canine enteropathies.

H2 Green Steels etablering i Boden och den allmänt hållbarhetsfokuserade samhällsutvecklingen innebär att kommunen är i behov av en hastig samhällsomställning. Bodens kommun hävdar att de på ca tre år behöver anpassa sig efter en samhällsutveckling som normalt sker under en 15 till 20-årsperiod. Detta betyder att Boden förväntas få en kraftig befolkningstillväxt fram till 2030. På så sätt kommer det bland annat behövas fler bostäder, fler skolor, fler aktivitetsmöjligheter och ett utökat samhällsutbud. Rapportens syfte har därför varitatt kartlägga hur den nuvarande situationen i Boden ser ut gällande samhällsservicen och det allmänna samhällsutbudet. Målet är på så sätt att få en indikation på vilka insatser som krävs samt var i kommunen de kan behöva implementeras.  Boden befolkningsmängd har under de senaste 50 åren genomgått både nedgångar och uppgångar. Just nu står kommunen inför en rejäl befolkningstillväxt till följd av de gröna satsningarna i regionen och uppskattar därför en total befolkningsökning på drygt 17% fram till 2030. Bodens kommuns arbete kring denna pågående samhällsomställning handlar om att utveckla infrastrukturen, se till att det finns en välfungerande kompetensförsörjning, utveckla attraktiva boende- och närmiljöer samt nyttja innovativa materialströmmar.  I detta utredningsarbete har kommunens generella samhällsutbud granskats, dels för att ta reda vad som egentligen finns, dels för att kartlägga hur detta är fördelat inom kommunen. Detta syftar till skolverksamheter, hälsovård, motion och friluftsliv, livsmedelsbutiker, restaurangersamt faciliteter som erbjuder tillfällig vistelse. Kartläggningen av samhällsutbudet har genomförts i kommunens egna interaktiva GIS-miljö och databas. Fristående information har även hämtats för att komplettera det som inte funnits tillgängligt. Kommunen har sedan delats in i olika områden utifrån en viss avståndsradie med H2GS som utgångspunkt. De olika områdena har en radie på 3 km, 6 km, 9 km, 15 km, 30 km och 50 km. Vidare har ett sjunde område inkluderats som berör allt utanför 50 km. Ett tydligt mönster har varit att samhällsutbudet är väldigt samlat inom en radie på 6 km, trots att det är relativt tomt inom de första 3 kilometerna. Detta är förvisso inte så märkligt eftersom Boden centrum återfinns inom detta område. Generellt sett tillkommer det ytterst få saker mellan radien på 15 km och 30 km, varvid det återigen ökar mellan 30 km och 50 km.  Genom att studera befolknings- och delområdesprognosen, H2GS placering, kommunens vision samt strukturen av samhällsservice och samhällsutbud, verkar det mest rimligt att expandera inom det primära utvecklingsområdet, dvs. inom en ca nio kilometers radie från H2GS anläggning. Detta utesluter dock inte nybyggnation i kommunens övriga delar eftersom en viktig aspekt med samhällsutvecklingen är att kunna erbjuda attraktiva boendemiljöer runt om i hela kommunen.

Att byta databas i ett befintligt system är svårt. För att ta reda på om en annan databas fungerar tillfredsställande till systemet finns inte mycket annat att göra än att testa. Syftet med detta arbete är att utvärdera om det är möjligt för SAAB att byta databas frånSybase ASE Express Edition till H2. För utvärderingen byggs ett så kallat ''Proof-of-Concept'' med den nya databasen kopplad till systemet. Med denna uppsättning görs tester för att undersöka skillnader i funktion och prestanda. Testerna görs genom att bygga arbetslaster som båda databaserna får hantera, där tiden det tar att utföra arbetet mäts. Det görs även förbättringar på linjära sökmetoder i systemet. Resultaten visar att Sybase-databasen har bättre prestanda när det gäller att läsa från databasen.Men att H2 har mycket bättre prestanda när det gäller att skriva till databasen.Slutsatsen som dras från utvärderingen är att H2 fungerar som en ersättare till Sybase ASE ExpressEdition. Systemets linjära sökmetoder utvärderas och ersätts med teoretiskt bättre binära sökmetoder. / The changing of database to an existing system is not easy. To find out if the new database willwork to a satisfying degree there is no other way than to test it. The purpose of this work is toevaluate if it is possible for SAAB to switch database from Sybase ASE Express Edition to H2. To evaluate the database, a Proof-of-Concept is created and connected to the systemWith this setup, tests are performed to investigate differences in functions and performance.The tests are preformed by building workloads that both databases will work with, where the time it takesto work with them is measured. Will also create an improvement on search methods that were linear. The results show that Sybase have a better performance when it comes to reading from the database while H2 have a better performance when it comes to writing to the database.  A conclusion is that H2 will work as a substitute to Sybase ASE Express Edition. The linear search methods as previouslyimplemented where replaced with binary search methods and the results show that the binary searchmethod were faster.

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This dissertation describes two related studies on hydrogenation and hydrodesulfurization of heterocyclic S-containing compounds. Alkyl substituted thiophenes are promising candidates for hydrogen carriers as the dehydrogenation reactions are known to occur under mild conditions. Four types of catalysts including supported noble metals, bimetallic noble metals, transition metal phosphides and transition metal sulfides have been investigated for 2-methylthiophene (2MT) hydrogenation and ring opening. The major products were tetrahydro-2-methylthiophene (TH2MT), pentenes and pentane, with very little C5-thiols observed. The selectivity towards the desired product TH2MT follows the order: noble metals > bimetallics > phosphides > sulfides. The best hydrogenation catalyst was 2% Pt/Al2O3 which exhibited relatively high reactivity and selectivity towards TH2MT at moderate temperatures. Temperature-programmed desorption (TPD) of hydrogen indicated that the H2 desorption amount was inversely related to the rate of TH2MT formation. Temperature programmed reaction (TPR) experiments revealed that pentanethiol became the major product, especially with HDS catalysts like CoMoS/Al2O3 and WP/SiO2, which indicates that poisoned or modified conventional HDS catalysts would be good candidates for further 2MT hydrogenation studies. The role of tetrahedral Ni(1) sites and square pyramidal Ni(2) sites in Ni2P hydrotreating catalysts was studied by substitution of Ni with Fe. The Fe component was deemed as a good probe because Ni2P and Fe2P adopt the same hexagonal crystal structure, yet Fe2P is completely inactive for hydrodesulfurization (HDS). For this purpose a series of NiFeP/SiO2 catalysts were prepared with different Ni:Fe molar ratios (1:0, 3:1, 1:1, 1:3, and 0:1) and investigated in the HDS of 4,6-dimethyldibenzothiophene at 300 and 340 oC. The uniformity of the NiFe series was demonstrated by x-ray diffraction analysis and by Fourier transform infrared (FTIR) spectroscopy of adsorbed CO. The position of substitution of Fe was determined by extended X-ray absorption fine structure (EXAFS) analysis. It was found that at 300 oC the HDS activity of the catalysts decreased with increasing Fe content and that this could be explained by the substitution of Fe at the more active Ni(2) sites. As temperature was raised to 340 oC, the activity of the Fe-containing samples increased, although not to the level of Ni2P, and this could be understood from a reconstruction of the NiFe phase to expose more Ni(2) sites. This was likely driven by the formation of surface Ni-S bonds, which could be observed by EXAFS in spent samples. / Ph. D.

Dynamical systems are mathematical models of physical phenomena widely used throughout the world today. When a dynamical system is too large to effectively use, we turn to model reduction to obtain a smaller dynamical system that preserves the behavior of the original. In many cases these models depend on one or more parameters other than time, which leads to the field of parametric model reduction. Constructing a parametric reduced-order model (ROM) is not an easy task, and for very large parametric systems it can be difficult to know how well a ROM models the original system, since this usually involves many computations with the full-order system, which is precisely what we want to avoid. Building off of efficient 𝐻-infinity approximations, we develop a greedy algorithm for efficiently modeling large-scale parametric dynamical systems in an 𝐻₂-sense. We demonstrate the effectiveness of this greedy search on a fluid problem, a mechanics problem, and a thermal problem. We also investigate Bayesian optimization for solving the optimization subproblem, and end with extending this algorithm to work with MIMO systems. / Master of Science / In the past century, mathematical modeling and simulation has become the third pillar of scientific discovery and understanding, alongside theory and experimentation. Mathematical models are used every day, and are essential to modern engineering problems. Some of these mathematical models depend on quantities other than just time, parameters such as the viscosity of a fluid or the strength of a spring. These models can sometimes become so large and complicated that it can take a very long time to run simulations with the models. In such a case, we use parametric model reduction to come up with a much smaller and faster model that behaves like the original model. But when these large models vary highly with the parameters, it can also become very expensive to reduce these models accurately. Algorithms already exist for quickly computing reduced-order models (ROMs) with respect to one measure of how "good" the ROM is. In this thesis we develop an algorithm for quickly computing the ROM with respect to a different measure - one that is more closely tied to how the models are simulated.

Dynamical systems are useful tools for modeling many complex physical phenomena. In many situations, we do not have access to the governing equations to create these models. Instead, we have access to data in the form of input-output measurements. Data-driven approaches use these measurements to construct reduced order models (ROMs), a small scale model that well approximates the true system, directly from input/output data. Frequency domain data-driven methods, which require access to values (and in some cases to derivatives) of the transfer function, have been very successful in constructing high-fidelity ROMs from data. However, at times this frequency domain data can be difficult to obtain or one might have only access to time-domain data. Recently, Burohman et al. [2020] introduced a framework to approximate transfer function values using only time-domain data. We first discuss improvements to this method to allow a more efficient and more robust numerical implementation. Then, we develop an algorithm that performs optimal-H2 approximation using purely time-domain data; thus significantly extending the applicability of H2-optimal approximation without a need for frequency domain sampling. We also investigate how well other established frequency-based ROM techniques (such as the Loewner Framework, Adaptive Anderson-Antoulas Algorithm, and Vector Fitting) perform on this identified data, and compare them to the optimal-H2 model. / Master of Science / Dynamical systems are useful tools for modeling many phenomena found in physics, chemistry, biology, and other fields of science. A dynamical system is a system of ordinary differential equations (ODEs), together with a state to output mapping. These typically result from a spatial discretization of a partial differential equation (PDE). For every dynamical system, there is a corresponding transfer function in the frequency domain that directly links an input to the system with its corresponding output. For some phenomena where the underlying system does not have a known governing PDE, we are forced to use observations of system input-output behavior to construct models of the system. Such models are called data-driven models. If in addition, we seek a model that can well approximate the true system while keeping the number of degrees of freedom low (e.g., for fast simulation of the system or lightweight memory requirements), we refer to the resulting model as a reduced order model (ROM). There are well established ROM methods that assume access to transfer function input-output data, but such data may be costly or impossible to obtain. This thesis expands upon a method introduced by Burohman et al. [2020] to infer values and derivatives of the transfer function using time domain input-output data. The first contribution of this thesis is to provide a robust and efficient implementation for the data informativity framework. We then provide an algorithm for constructing a ROM that is optimal in a frequency domain sense from time domain data. Finally, we investigate how other established frequency domain ROM techniques perform on the learned frequency domain data.

This analytical study evaluates the response characteristics of a two-degree-of freedom quarter-car model, using passive and semi-active dampers, along with a seven-degree-of-freedom full vehicle model. The behaviors of the semi-actively suspended vehicles have been evaluated using skyhook, groundhook, and hybrid control policies, and compared to the behaviors of the passively-suspended vehicles. The relationship between vibration isolation, suspension deflection, and road-holding is studied for the quarter-car model. Three main performance indices are used as a measure of vibration isolation (which can be seen as a comfort index), suspension travel requirements, and road-holding quality. After performing numerical simulations on a seven-degree-of-freedom full vehicle model in order to confirm the general trends found for the quarter-car model, these three indices are minimized using optimization techniques. The results of this study indicate that the hybrid control policy yields better comfort than a passive suspension, without reducing the road-holding quality or increasing the suspension displacement for typical passenger cars. The results also indicate that for typical passenger cars, the hybrid control policy results in a better compromise between comfort, road-holding and suspension travel requirements than the skyhook and groundhook control policies. Finally, the numerical simulations performed on a seven-degree-of-freedom full vehicle model indicate that the motion of the quarter-car model is not only a good approximation of the heave motion of a full-vehicle model, but also of the pitch and roll motions since both are very similar to the heave motion. / Master of Science