Texte remanié de: Dissertation--Mayence, Allemagne--Universität Mainz. / Bibliogr. p. 231-242.

This thesis study the possibility of riser slugging control in oshore oil productionusing a subsea choke valve. A 5-state simplied model of a well-pipelinerisersystem is introduced and tted to a reference model in the ow simulatorOLGA. The models have two inputs, a subsea valve at the wellhead and a topsidevalve at the top of the riser. The eect the valves have on the behavior ofthe simplied model are tted to simulation data from the OLGA-model usingbifurcation diagrams.An input-output controllability analysis of the simplied model show thatanti-slug control using a subsea valve at the wellhead is more dicult than theconventional solution, which is to use the topside choke valve. This is conrmedby simulations on the simplied model using Hinfinity-controllers.Stabilizing control of the OLGA-model using the subsea valve was unsuccessful,despite testing dierent measurement combinations and control structures.A more promising solution for controlling riser slugging using a subsea valve istested in OLGA, where a subsea valve located near the base of the riser can keepthe system stable at riser slugging conditions. This is also seen in an experimenton a small scale ow lab.

Subsea petroleum extraction systems may be large and complex, and many decisions affect the production. Maintaining high production levels is not a trivial task. As decisions are made based on available information and experience, better decisions come with better information. Decision support tools may provide essential information to achieve better production levels.In this master thesis, different methods are proposed as decision support tools. The aim is to increase the production from a part of a subsea production system, consisting of a manifold with seven producing wells and two flowlines, given certain system constraints. The methods are based on well models and numerical optimization, and both static and dynamic optimization is considered. The well models are non-linear, and binary decisions are also present. The problems that arise are complex MINLP problems, and are solved by combining ’brute force’, ’Branch & Bound’, and a nonlinear solver. The solution of the problems is implemented in MATLAB, and tested on predefined test scenarios, with no, little or extensive dynamics present. The performance is assessed by simulations, and by calculating the resulting average production.It was found that static optimization to decide the well settings, such as valve openings and flowline routing, has a great potential to increase the oil production from the system. The results when applying a dynamic approach to the system were not conclusive, but the methods proposed showed no indications of any major performance increase, relative to applying only static optimization.

Zugl.: Mainz, Univ., Diss., 2002

Orientador: Antonio Manoel Mansanares / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-05T12:36:29Z (GMT). No. of bitstreams: 1 Silva_VagnerLuizda_M.pdf: 2632810 bytes, checksum: 349b270849e09c9dfcac5d7edfeefa03 (MD5) Previous issue date: 2005 / Resumo: Os vidros dopados com semicondutores são objeto de grande interesse como materiais ópticos não lineares e estudos intensivos acerca dos efeitos de confinamento quântico e não linearidade ótica tem sido realizados. Apesar do grande interesse nas propriedades óticas desses materiais, os dados térmicos e opto-térmicos são ainda escassos e raros. Neste trabalho utilizamos a espectroscopia de lente térmica na configuração de modo descasado para determinar a difusividade térmica e o comportamento do coeficiente de temperatura do índice de refração dn/dT em amostras de vidros de borossilicato dopados com CdTe. As amostras estudadas foram vidros tratados termicamente a 540oC para períodos de 20, 65, 150, 255, 300, 360 e 480 min. Também foram realizados espectros fotoacústicos com estas amostras. Para os espectros fotoacústicos notamos que as amostras tratadas para 20 e 65 min são quase transparentes na faixa do visível, apresentando banda de absorção no ultra-violeta, característica de dielétricos tais como esses vidros. Para amostras tratadas a 150 min ou mais, aparece uma banda de absorção adicional no visível, e que se desloca para comprimentos de onda mais longos com o tempo de tratamento. Esta banda é consequência dos efeitos de confinamento quântico do elétron, associado à existência de nanocristais de CdTe no vidro. Os resultados de lente térmica mostraram os valores de difusividade térmica encontrados em função do tratamento térmico das amostras. Estes valores são próximos à difusividade térmica de vidros de borossilicato relatados na literatura e mostram uma diminuição pequena do parâmetro térmico para amostras tratadas para longos períodos. Este efeito pode ser causado pela perturbação na propagação de calor introduzida pelos pontos quânticos. O comportamento de dn/dT (em 632,8 nm) obtido das medidas de Lente Térmica, devidamente normalizados pelo Sinal Fotoacústico, mostrou clara correlação com a evolução das bandas de absorção em função da temperatura de tratamento, indicando que o efeito da modulação térmica se dá principalmente através do deslocamento da banda de absorção / Abstract: Glasses doped with semiconductors are of great interest as non-linear optical materials, and intensive studies on quantum confinement and non-linear optics in these structures have been carried out. Despite the importance of their optical properties, thermal and opto-thermal properties are still not well characterized in these materials. In this work we used the thermal lens technique to determine the thermal diffusivity and the behavior of the temperature coefficient of the refractive index, dn/dT, in CdTe quantum dots borosilacate glasses. Samples annealed at 540oC for 20, 65, 150, 255, 300, 360 and 480 min were investigated. Optical absorption spectra were also determined using photoacoustic technique. The photoacoustic spectra for the samples treated for 20 and 65 min did not show signifficant absorption in the visible range, presenting only the well known UV band of glasses. The samples treated for 150 min and further presented an additional band in the visible, which shifts up to long wavelengths with annealing. This band arises in the quantum confinement in the CdTe nanocrystals dispersed in the glass matrix. Thermal lens measurements allowed the determination of the thermal diffusivity of the samples as a function of the thermal treatment. The found values are in good agreement with literature data for borosilicate glasses, and present a slight decrease for samples treated for long periods. This decrease can be related to the perturbation introduced by the CdTe aggregates in the heat propagation. Finally, the behavior of dn/dT (at 632,8 nm) obtained through thermal lens measurements showed a net correlation with the evolution of the absorption bands with thermal treatment. This indicates that the effect of the thermal modulation is dominated by the shift of the absorption band to longer wavelengths / Mestrado / Física / Mestre em Física

Aim of this thesis is the design of experimental equipment for studying the formation of lubricating films in contacts lubricated machine parts Liquid gases with the following parameters: experimental device to operate on the principle of optical tribometer, the design will be modified so that it can be used to deleting contacts liquid gases.

Made available in DSpace on 2017-07-24T19:22:05Z (GMT). No. of bitstreams: 1 MANOELA HASS DOLINSKI THOMASSEWSKI.pdf: 1885236 bytes, checksum: f6df4dd8ee0fdb0bea20dba5b9c53058 (MD5) Previous issue date: 2008-02-26 / The purpose of this study was to measure mass loss and surface roughness (Ra) changes of differents glass ionomer cement indicated to atraumatic restorative treatment, with a resin composite used as control material, after a simulated toothbrushing test. The surface characteristics before and after abrasion were evaluated on scanning electron microscopy (SEM). The tested materials were: Vitro Fil LC® ,Fuji IX® , Vitro Molar® , Maxxion R®, and the resin composite Filtek Z100®. Ten samples (6mm in diameter and 5mm thick) on all samples from each were prepared according to manufacturers’ instructions. Toothbrushing abrasion was performed on all specimens from each of the materials using a simulator. The mass loss, surface roughness and qualitative analyse were assessed before and after 20000 brushstrokes, using Shimadzu analytical balance of 0,0001g accuracy, a Mitutoyo surftest-301 and Shimadzu SSX-550 Superscan respectively. The measurements of both properties were statiscally compared by Anova one-way and then paired t-test and Tukey’s test. Correlation between mass loss and surface roughness was calculated. The level significance was α=5% (p<0,05). All materials presented a statistically significant mass loss comparing initial and final values. The loss mass in order decreasing was Vitro Fil LC>Maxxion R> Vitro Molar>Filtek Z100>Fuji IX. All materials became rougher with the exception of Vitro Molar that presented low roughness after toothbrushing test. There was no correlation between wear and surface roughness and SEM observations were in accordance to those roughness measured. In conclusion, the findings of this study showed that, the high viscosity glass cement ionomer presented wear and roughness seems to control material and the fluoride release propertie, this may be adequate for atraumatic restorative treatment. However, long-term clinical evaluation are necessary to better indicate this category of materials / O objetivo deste estudo foi mensurar a perda de massa e as alterações de rugosidade média superficial (Ra) de diferentes cimentos de ionômero de vidro indicados para tratamento restaurador atraumático tendo uma resina composta como material controle, após teste de escovação simulada. As características de superfície antes e após abrasão foram avaliadas em microscópio eletrônico de varredura (MEV). Os materiais testados foram: Vitro Fil LC® ,Fuji IX® , Vitro Molar® , Maxxion R®, e a resina composta microhíbrida Filtek Z100®. Dez amostras (6mm de diâmetro e 5mm de espessura) de cada material foram confeccionados de acordo com as instruções do fabricante. O teste foi conduzido em uma máquina de escovação simulada, em todas as amostras de todos os materiais, totalizando 20000 ciclos. Antes e após o teste, a massa, rugosidade e analise qualitativa em MEV, de cada material foram aferidas em um balança analítica Shimadzu de 0,0001g de precisão, pelo equipamento Mitutoyo modelo surftest-301 e pelo microscópio Shimadzu SSX-550 Superscan., respectivamente. Os resultados das variáveis perda de massa e rugosidade foram analisados pelo teste ANOVA de um critério e então o pós-teste para comparações múltiplas de Tukey, com o objetivo de identificar entre quais grupos situavam as diferenças. Para analisar a relação entre perda de massa e rugosidade média foi utilizada a análise de regressão linear. O nível de significância empregado foi de α=5% (p<0,05), utilizado para todas as análises. Todos os materiais apresentaram diferenças estatísticas de perda de massa entre valores iniciais e finais. A perda de massa em ordem decrescente foi Vitro Fil LC>Maxxion R> Vitro Molar>Filtek Z100>Fuji IX. Os materiais se tornaram mais rugosos exceto o Vitro Molar que apresentou menor rugosidade após teste. Não houve correlação entre perda de massa e rugosidade superficial. Observações ao MEV estavam de acordo com as medidas de rugosidade. Concluindo, os achados deste estudo mostraram que os cimentos de alta viscosidade apresentaram desgaste e rugosidade semelhantes ao material controle e ainda possuem a propriedade de liberar flúor, sendo adequado para tratamento restaurador atraumático. Entretanto, avaliações clínicas são necessárias para melhor indicar esta categoria de material.

This thesis evaluates metafictional self-reflexivity, and presents it within the scope of certain structuralist and post-structuralist approaches especially by referring to William Gass&rsquo / definition of metafiction and Raymond Federman&rsquo / s theories on the devices of metafiction. Then aspects of the works of William Gass&rsquo / Willie Master&rsquo / s Lonesome Wife and Laurence Sterne&rsquo / s The Life and Opinions of Tristram Shandy are discussed within this framework.

This doctoral thesis contributes to the ongoing scholarly conversation on literary representation of musical sounds, forms, and compositions. My close examination of the tangible presences of Western art music in the fiction of three contemporary American novelists relocates traditional foci of intermediality and word and music studies from referential precision and structural equivalence across the arts to the problem of readerly experience of music through fictional narrative. Exploring a variety of diegetic encounters with music in William T. Vollmann's Europe Central (2005), William H. Gass's Middle C (2013), and Richard Powers's Orfeo (2014), I draw from cognitive narratology and the philosophy of music, among others, to construct a concise model of musical experience and a system of its literary correlatives, which can provide for the reader's enactive response to music-related themes and means in fiction. I discuss the different strategies the writers apply to communicate the presumably elitist experience of Western classical music as suggestive and relevant to their 21st-century readerships, whether big or small. I order my chapters dialectically, regarding the three authors' literary approaches to musical experience as thesis, antithesis, and synthesis. In Chapter I, Vollmann's intermedial transpositions of Dmitri Shostakovich's fictionalized works are shown to be framed by a mimetic bias, under which diegetic music functions as a characterization means for the author's historical preoccupations. The thesis (i) I infer from Vollmann's approach is that music is part of the fictional reality representative/informative/definitive of what that reality is like. Chapter II is devoted to Gass's metafictional distrust of representation, whereupon his novelistic narrative discards diegetic music almost completely and points out ways of experiencing verbal textures musically. Gass's method is thus antithetical (ii) to Vollmann's: music is a metaphor for creativity, indifferent to the subject matter and/or plot, which at representation level may well be a parodic perversion of the very idea of creativity. Powers's balanced treatment of musicalized content and form and his generous supply of multivalent experiential cues are forged to appeal to a broader reading audience, as I argue in Chapter III. In what I see as a synthesis (iii) of Vollmann and Gass, Powers's storyworld contains abundant diegetic music that constructs narrative settings and drives the events of the plot, but is itself graspable through musical metaphors. The findings of the thesis open new directions for research into musico-literary reception. Encouraging a revival of reader-response awareness in literary analysis, musicalized fiction is an untrivial subject for interactive theoretical scrutiny by psychologists and philosophers of music, transmedial narratologists, and cognitive scientists. Empirical studies of actual readers' experience of musicalized prose may prove particularly promising in further investigation of this intersectional phenomenon.

This diploma thesis will be focused on the identification and quantification of PAHs with molecular mass exceeding 278 Da by separation and spectrometric methods available at the laboratories of ICTEP.