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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Implementierung und Umsetzbarkeit eines Tablet-gestützten Screenings auf Unterstützungsbedarf in der Radioonkologie / Implementation and application for the need of support in the field of radiooncology via tablet screening

Häckel, Annalena January 2017 (has links) (PDF)
Die Inzidenz und Prävalenz von Krebserkrankungen präsentiert sich in den vergangenen Jahren ungebrochen hoch. Durch die stetige Optimierung der Versorgung werden Betroffenen neuartige Optionen offeriert. Moderne Onkotherapie zeichnet sich durch sektorenübergreifende Kooperation aus. Diese komplexen Versorgungskonzepte können durch innovative Technologien simplifiziert werden. Vorliegende Arbeit erörtert die Frage nach der Umsetzbarkeit Tablet-gestützter Screenings in der Routine der Strahlenmedizin. Die Erfassung der ESAS-Items und des Unterstützungsbedarfs ermöglichte nach dem Vorbild kanadischer Versorgungskonzepte definierte Aussagen zur Qualität der medizinischen Versorgung. Im Rahmen der Studie erhielten Tumorpatienten vor der perkutanen Radiotherapie (T1) ein Tablet-gestütztes Symptom-Screening. Das Tablet-Screening wurde von den Teilnehmern bezüglich Bedienung und Nutzerfreundlichkeit evaluiert. Nach Abschluss der Radiotherapie erfolgte eine telefonische Nachbefragung der Teilnehmer (T2). Insgesamt partizipierten 332 Krebspatienten am Tablet-Screening. 79 potentielle Studienprobanden nahmen nicht teil. Als Hauptursachen zeigten sich fehlende Zeit (21,5%), die Teilnahme an sonstigen Studien (20,3%) und zu hohe psychische Belastungen (17,7%). Der Anteil der Screening-Teilnehmer mit fundierten Vorkenntnissen im Umgang mit Tablet-PCs (15,7%) war gering. Probanden mit Tablet-Vorerfahrungen waren signifikant jünger als Unerfahrene. Anwendung und Nutzerfreundlichkeit erlangte hohe Zustimmung. Die wenigen (21,7%) Befürworter konventioneller Stift-Papier-Fragebögen waren signifikant älter. 219 Screening-Teilnehmer stellten ihre ausgewerteten Symptom-Fragebögen weiteren Auswertungen zur Verfügung. Der Performance-Status wurde von Patient und Mediziner eher divergent bewertet (ĸ=0,254). Von T1 zu T2 nahm der Anteil positiv gescreenter Probanden ab. Kurativpatienten markierten bei den ESAS-Items Müdigkeit, Kurzatmigkeit und Sonstiges signifikante Symptomverbesserungen. Bei Palliativpatienten zeigte Kurzatmigkeit signifikante Verbesserung, Depressionen hingegen signifikante Verschlechterung. Der schwächste Unterstützungsbedarf (23,3%) wurde beim ,,Bedarf an Informationen beim Erstellen von Patientenverfügungen‘‘ registriert. Die BUKA-Studie konnte die Chancen Tablet-gestützter Befragungen in der Routine der Radioonkologie darstellen. Das Screening markierte durchgängig positive Bewertungen sowie große Akzeptanz. Die positiven Ergebnisse deckten sich mit denen anderer Studien bezüglich EDV-gestützter Datenerhebung. Die oftmals nicht ausreichendende Zeit zur Studienteilnahme war jedoch nicht auf eine zu zeitintensive Bedienung von Tablet-PCs zurückzuführen. Die Anzahl der Screening-Items sollte der kurzen Wartezeit der Strahlenambulanz angepasst werden. EDV-Screenings sollten darüber hinaus zukünftig bereits von zuhause absolviert werden. Die zunehmende Technisierung des Alltags lässt den Anteil PC-erfahrener Patienten weiter ansteigen. Die Einführung EDV-gestützter Versionen bietet eine effektive Möglichkeit des Patienten-Monitoring als Grundlage multidisziplinärer onkologischer Versorgung. Infolge der zunehmenden PC-gestützten Verarbeitung hochsensibler Patientendaten ist die Gewährleistung vollkommener Datensicherheit dringend notwendig. Im Gegensatz zu anderen Arbeiten präsentierte das Studienkollektiv überwiegend Kurativpatienten mit gutem Allgemeinzustand. Trotz geringerer Symptombelastung konnten auch hier die positiven Effekte der Radiotherapie dargestellt werden. Der hohe Unterstützungsbedarf erschien oftmals dem mangelnden medizinischen Verständnis der Betroffenen geschuldet. Kurativpatienten äußerten deutlich mehr Interesse aktiv an der Therapie teilzuhaben. Palliativpatienten erschienen durch das Übermaß an Therapien entkräftet. / In recent years the incidence and prevalence of carcinosis remained unchanged high. The continous improvement of patient centred care offers unknown possibilities. Modern cancer therapy is distinguished by overlapping cooperation. These extensive treatment options can be simplified by innovative technology. The study in hand investigates the implementabilitiy of a tablet screening in the field of radiooncology. Aquiring data on the ESAS Items and on the individual request of support as done in the Canadian cancer support system enables us to give evidence. In the present study tumor patients were screened before receiving percutane radiotherapy (T1) on a special symptom screening scale via tablet. The participants also evaluated the tablet screening on handling and usability. After the radiotheray the participants were questioned again via phone interview. In total 332 cancer patients took part in the tablet screening. 79 potential participants didn’t participate. The main reasons were the lack of time (21,5%), the participation in other studies (20,3%), and the high psychic strain (17,7%). The the number of participants with a previous knowledge in the use of tablet-computer was low (15,7%). Furthermore, they were significantly younger than the participants with that hat no previous knowledge in the use of a tablet. Handling and usabilityshowed high acceptance. The few supporters of conventional paper-pencil -quetionnaires were significantly older. In total 219 screening patients did consent the further evaluation and analysis of their screening results. Patients and physicians showed divergent results in theassessment of the patient’s performance status (k=0,254). The rate of participants with positive screening results decreased from T1 to T2. In the ESAS items fatigue, dyspnoea and other problems curative patients showed significant symptom improvement. Patients with palliative treatment also represented with significant improvemet in dyspnoea whereas the rate on depression increased significantly. Patients showed the lowest interest in the provision on information on making an advance health care directive (23,3%). The BUKA study was able to represent the opportunities of tablet screening in the routine of radiooncology. The tablet screening did resilt in an overall positive feedback and demonstrated high rate of acceptance. Similar positive results were also showen in several previous studies concerning the use computerized questionnaires. The participants complaints on the lack of time did not refer to the use of the computerized questionnaire itself but on the provided amount of time for the questionaire itself. In the future, the amount of screening items should be adjusted to the amount of waiting time in the ambulance of the radiooncology. Furthermore, computerized screening should be considered to be already done at home. The upcoming computerization in the daily routine will increase rate people with previous knowledge on computerized systems and applications even further. The implementation of computerized systems provides the opportunity of a very effective patient monitoring as a foundation vor multidisciplinary oncological treatment. As a result of the increasing digitalization of patient data the data protection is extremely important and future challenge but must be basic prerequisite. In contrast to other studies our patients predominantly represented a good performance status. Despite the low symptom stress the positive effects of a radiotherapy could be illustrated here as well. The high demand of support seemed to be due to the lack of understanding of medical information. Curative patients showed significantly more interest in taking actively part in their therapy whereas patients with palliative treatment seemed to be rather exhausted with the excess of palliative treatment options.
52

Recheneffiziente Implementierung einer approximierten modellprädiktiven Regelung auf einem Industrie-PC

Karau, Fabian, Leuer, Michael 12 February 2024 (has links)
Die modellprädiktive Regelung (MPC) hat sich in vielen industriellen Anwendungen bewährt. Ein Nachteil ist jedoch der hohe Rechenaufwand, bedingt durch die erforderliche Lösung eines Optimierungsproblems in jedem Abtastschritt. In diesem Beitrag wird die entworfene MPC daher durch ein neuronales Netz approximiert. Als neuronales Netz wird ein Multi-Layer-Perceptron (MLP) verwendet. Mit dem trainierten MLP sind nur noch Matrix-Vektor-Multiplikationen erforderlich, die effizient berechnet werden können. Das trainierte MLP wird in C++ Code übersetzt und durch einen Industrie- PC ausgeführt. Am akademischen Beispiel einer Wippenwinkel-Regelung wird die Funktionsfähigkeit und der geringere Rechenbedarf demonstriert.
53

A PC based expert system for positional tolerance allocation

Mehta, Anuj January 1994 (has links)
No description available.
54

A prom burner module extension card for an IBM PC

Chen, Chiung-Hsing January 1989 (has links)
No description available.
55

A Pen-Based Interactive Animation Environment for Effective Communication using a Tablet PC

Holman Jr, Jerome Thomas 30 October 2019 (has links)
The human mind is a churning engine, processing all forms of sensory input. Information that reaches these senses is powerful, facilitating and deepening understanding. Animations access sight. They provide a rich visual model that portrays not only information about the system graphically, but they also present information about the relationships and interactions in that model over time. However, the complexity of today's software for constructing animations limits their use and isolates animations to a small set of scenarios. One such eliminated scenario is being able to create and manipulate animations in real time, while a conversation takes place. The human mind comprehends from manipulation, trial, and error. Animations are productions. Instructors cannot manipulate and recreate animations within the time constraints of a classroom. Developers cannot recreate animations within the time constraints of a meeting. This thesis explores the engineering of a modeling environment prototype for creating animated models. By building an environment designed to leverage the capabilities of Microsoft's Tablet PC operating system, this thesis contributes a new approach to creating animations and visualizations. This prototype demonstrates a pen-based user interface that decreases the time and effort required to create an animation by enabling users to create an animation by simply drawing a model and animating it. The Tablet PC hardware and software provide developers with the capabilities necessary to create software that works as naturally as the pen and paper. With the Tablet PC's Ink technology, users can draw models and simply draw the paths where the objects in that model should follow. This thesis explores the design of the environment, the research prototype named Model Pad, and explores its importance, its contribution, and its unique design based on the capabilities of the Tablet PC. As mobile computers become increasingly central to the workplace, the ability to create animations quickly and easily while talking with others, while presenting in front of an audience or a class, or while working with a team of engineers allows animation to become a natural part of the way we visually communicate information. The Model Pad environment is merely a first step in the direction of creating fully pen-based modeling and animation tools. The concepts it builds form the foundation of understanding how to express animations that are more complex. This thesis and the Model Pad environment provide the initial framework for building pen-based animation tools on the Tablet PC, allowing simple models to be expressed in methods as simple as using a pen and paper. This solution enables people to construct simple models in real time, enabling a rebirth of the power of animation for education and engineering design. / Master of Science / The human mind is a churning engine, processing all forms of sensory input. Information that reaches these senses is powerful, facilitating and deepening understanding. Animations access sight. They provide a rich visual model that portrays not only information about the system graphically, but they also present information about the relationships and interactions in that model over time. However, today’s software tools for constructing animations are complex, unnatural and limiting to for Students, Instructors, and Developers. This thesis explores the engineering of a modeling environment prototype for creating animated models with a natural form of input, a pen. By building an environment designed to leverage the capabilities of Microsoft’s Tablet PC, a personal computer designed with a built-in interactive screen that enables users to draw on the screen to interact with it directly, this thesis contributes a new approach to creating animations and visualizations. This prototype demonstrates a pen-based user interface that decreases the time and effort required to create an animation by enabling users to create an animation by merely drawing a model and animating it. The Tablet PC hardware and software provide developers with the capabilities necessary to develop software that works as naturally as the pen and paper. With the Tablet PC’s Ink technology, users can draw models and merely draw the paths where the objects in that model should follow. This thesis explores the design of the environment, the research prototype named Model Pad, and explores its importance, its contribution, and its unique design based on the capabilities of the Tablet PC. As mobile computers become increasingly central to the workplace, the ability to create animations quickly and efficiently while talking with others, while presenting in front of an audience or a class, or while working with a team of engineers allows the animation to become a natural part of the way we visually communicate information. The Model Pad environment is merely a first step in the direction of creating fully pen-based modeling and animation tools. The concepts it builds form the foundation of understanding how to express animations that are more complex. This thesis and the Model Pad environment provide the interaction primitives for building penbased animation tools on the Tablet PC, allowing simple models to be expressed in methods as simple as using a pen and paper. This solution enables people to construct simple models in real time, enabling a rebirth of the power of animation for education and engineering design.
56

Zum besseren Verständnis von Evaluationen verschiedener Lehrformate: Wie Charisma der Dozierenden und studentische Technikaffinität die Wahrnehmung didaktischer Qualität beeinflussen / For a better understanding of evaluations of different teaching formats: How teacher charisma and student digital affinity influence the perception of didactic quality

Weigel, Sandra Carina January 2024 (has links) (PDF)
Seit Beginn des neuen Jahrtausends haben Tablets in der medizinischen Lehre zunehmend an Bedeutung gewonnen. In dieser Studie wurden ein Tablet-basiertes und ein Dozierenden-zentriertes Lehrformat im Rahmen eines Radiologie-Seminars verglichen. Ziel war es, vergleichende Erkenntnisse über selbsteingeschätzten und objektiven Lernzuwachs und empfundene didaktische Qualität zu erlangen und mögliche Einflüsse des Charismas der Dozierenden sowie der studentischen Technikaffinität auf diese Variablen zu untersuchen. Von n=366 Studierenden wurden über drei Semester hinweg Daten zu studentischer Technikaffinität generell sowie didaktischer Qualität und Zufriedenheit mit den Seminaren abhängig vom Lehrformat erhoben. Im letzten Studiensemester nahmen die Studierenden zudem eine Selbsteinschätzung ihres Lernzuwachses vor und legten ein Wissens- und Bildinterpretationstestat sowie eine Einschätzung des Charismas der Dozierenden ab. Mittels Maximum-Likelihood Faktorenanalyse erfolgte eine Strukturaufklärung der didaktischen Qualität und des Charismas. Pearson-Korrelationskoeffizienten wurden zur Untersuchung möglicher Korrelationen zwischen den Variablen berechnet. Ein Strukturregressionsmodell des Charismas der Dozierenden, der studentischen Technikaffinität und der didaktischen Qualität wurde erstellt und daraus eine lineare Regressionsgleichung abgeleitet. Dem Tablet-basierten Lehrformat wurden signifikant höhere Werte in didaktischer Qualität und studentischer Zufriedenheit zugeschrieben. Das Dozierenden-zentrierte Format schnitt hingegen in selbsteingeschätztem und objektivem Lernzuwachs signifikant besser ab. Ausschließlich im Tablet-basierten Unterricht korrelierte das Charisma der Dozierenden mit dem selbsteingeschätzten Lernzuwachs. Die studentische Technikaffinität wirkte sich in diesem Format stärker auf die didaktische Qualität aus. Zudem wurden gute Organisation, eindeutige Lernziele und adäquate Lernformvariation als bedeutsame Faktoren identifiziert. Diese Studie hebt die Relevanz des dozentischen Charismas und der studentischen Technikaffinität für die Sicherstellung hoher didaktischer Qualität in Tablet-basiertem Unterricht hervor. Sie zeigt zudem die Wichtigkeit der Kongruenz von Lernzielen, Lehrkonzept und Prüfungsmethode dieses Lehrformats auf, um hohe Studienleistungen sicherzustellen. Die untersuchten Faktoren sollten bei Entwurf digitaler Lehrkonzepte über spezifische Messinstrumente objektiviert und bei Bedarf geschult oder angepasst werden, um eine erfolgreiche Integration digitaler Medien in die medizinische Lehre zu gewährleisten. / Since the beginning of the new millennium, tablets have become increasingly important in medical teaching. In this study, a tablet-based and a teacher-centred teaching format were compared in the context of a radiology seminar. The aim was to gain comparative insights into estimated and objective learning gain and perceived didactic quality, and to investigate possible influences of teacher charisma and student digital affinity on these variables. Data on student digital affinity in general as well as didactic quality and satisfaction with the seminars depending on the teaching format were collected from n=366 students over three semesters. In the last semester, students also estimated their learning gain, completed a knowledge and image interpretation test and rated teacher charisma. Maximum likelihood factor analysis was used to provide a structural elucidation of didactic quality and charisma. Pearson correlation coefficients were calculated to investigate possible correlations between the variables. A structural regression model of teacher charisma, student digital affinity, and didactic quality was constructed and a linear regression equation was derived. The tablet-based teaching format was attributed significantly higher values in didactic quality and student satisfaction. The teacher-centred format, on the other hand, performed significantly better in estimated and objective learning gain. Only in tablet-based teaching did teacher charisma correlate with estimated learning gain. Student digital affinity had a stronger effect on didactic quality in this format. In addition, good organization, clear learning objectives, and adequate variation of learning activities were identified as important factors. This study highlights the relevance of teacher charisma and student digital affinity in ensuring high didactic quality in tablet-based teaching. It also shows the importance of congruence of learning objectives, teaching concept, and assessment method of this teaching format to ensure high academic performance. The factors examined should be objectified via specific measuring instruments when designing digital teaching concepts and trained or adapted as necessary to ensure successful integration of digital media in medical teaching.
57

Cálculo do equilíbrio de fases em sistemas contendo hidrocarbonetos em fase gasosa com altos teores de CO2 e traços de água. / Phase equilibrium calculations for systems with hydrocarbons in gas phase with high content of CO2 and traces of water.

Carvalho, Danilo Pereira de 02 September 2016 (has links)
Os grandes campos de petróleo offshore recentemente descobertos na camada pré-sal, localizada no sudeste do Brasil, representam um avanço significativo da participação brasileira nas reservas mundiais de hidrocarbonetos, que ainda são a principal matriz energética mundial. Nesse cenário, torna-se importante o desenvolvimento da produção desses campos. Um dos principais desafios tecnológicos da exploração desses campos é o processamento do gás natural associado, que possui altos teores de dióxido de carbono CO2. Esse contaminante deve ser separado para possibilitar a injeção no reservatório e/ou o escoamento desse gás através de dutos submarinos, dadas as restrições na legislação ambiental. Nas plantas de processamento instaladas no convés de grandes embarcações, são previstas instalações para a separação do CO2 e a remoção de umidade do gás a fim de evitar a formação de hidratos e a corrosão acentuada das linhas de escoamento, pois tanto a injeção quanto a exportação do gás são realizadas em condições de pressão e temperaturas extremas. Nesse contexto, o conhecimento acurado das condições em que se forma uma fase aquosa líquida é importante para garantir a viabilidade técnica e de segurança dessas operações. Considerando a relevância do assunto e as limitações da literatura para os cenários enfrentados no pré-sal brasileiro, esse trabalho tem o objetivo de fazer um estudo abrangente do equilíbrio de fases em sistemas contendo hidrocarbonetos em fase gasosa com altos teores de CO2 e traços de água, visando à obtenção de modelo para cálculo do ponto de orvalho da água. O uso de modelos rigorosos baseado na teoria dos fluidos associativos (PC-SAFT) mostrou-se adequado para o cálculo das condições de saturação em amplas faixas de pressão e temperatura. Com base em dados experimentais publicados foi possível fazer um ajuste preciso dos parâmetros de interação binária da equação de estado PC-SAFT. Como resultado, obteve-se um modelo capaz de descrever o comportamento de fases em misturas de hidrocarbonetos com composição próxima das encontradas no pré-sal brasileiro. / The giant offshore petroleum fields recently discovered in the pre-salt layer on the southeast of Brazil represent a significant increment in the Brazilian share of the global hydrocarbon reserves, which is still the most important energetic matrix. In this scenario, the development of production for these petroleum fields becomes important. One of the main technological challenges posed by these fields is the processing of the associated gas, which contains high amounts of carbon dioxide (CO2). Due to environmental laws, this contaminant must be separated to allow the injection back into the reservoir and/or the gas flow through subsea pipelines. The gas processing plants installed on large vessels comprise facilities that remove CO2 and moisture from natural gas, to prevent hydrate formation and severe corrosion throughout the pipelines, as both gas injection and gas exportation are performed in extreme pressure and temperature conditions. Thus, the accurate knowledge of conditions in which aqueous liquid phases are formed is important to ensure the technical viability and operational safety of these operations. Considering the relevance of this subject and the limitations of published works for the Brazilian pre-salt scenario, this work presents a comprehensive study on the phase equilibrium in systems with hydrocarbons in gas phase with high content of CO2 and traces of water, aiming at developing a model to calculate the dew point of water. The use of a rigorous method based on the associating fluid theory (PCSAFT) has shown to be appropriate to calculate the saturation condition for a large range of pressure and temperature. Based on the experimental data published, the fitting of the binary interaction parameter from the PC-SAFT equation of state was carried out. The resulting model was able to describe the phase behavior of hydrocarbon mixture with composition similar to those found in the Brazilian pre-salt.
58

Nesąlytinė savitųjų ir technologinių defektų spektroskopija Si, Ge ir GaN dariniuose / Contactless spectroscopy of native and technological defects in Si, Ge and GaN structures

Uleckas, Aurimas 01 October 2012 (has links)
Viena iš pagrindinių priežasčių, keičiančių puslaidininkinių prietaisų parametrus, yra elektriškai aktyvūs defektai. Gilieji lygmenys sąlygoja krūvininkų gyvavimo trukmės mažėjimą medžiagoje, todėl blogėja krūvininkų surinkimo koeficientas puslaidininkiniuose detektoriuose, išauga energijos nuostoliai galios prietaisuose bei mažėja šviesos diodų našumas. Elektriškai aktyvių radiacinių bei technologinių defektų charakterizavimas yra aktualus vystant naujų, daugiasluoksnių puslaidininkinių struktūrų formavimo technologijas bei puslaidininkinių detektorių darbo parametrų optimizavimui. Šiame darbe buvo sukurta nesąlytinė laike išskirtosios spektroskopijos metodika giliųjų lygmenų puslaidininkinėse struktūrose įvertinimui kambario temperatūroje. Ši metodika įgalina sinchroniškai kontroliuoti gaudyklių aktyvacijos energiją ir krūvininkų gyvavimo trukmę. Sukurtas, išbandytas ir sukalibruotas mikrobangomis zonduojamo fotolaidumo kinetikų matavimo prietaisas, skirtas krūvininkų gyvavimo trukmės bandinio briaunoje ir plokštumoje įvertinimui bei technologinių procesų kontrolei. Šiais metodais buvo įvertinti defektų parametrai hadronais apšvitintame, įvairiais metodais užaugintame Si. Taip pat įvertinta legiravimo, metalų implantacijos ir apšvitinimų įtaka Ge struktūrų rekombinacijos charakteristikoms. Rekombinacijos parametrų kontrolei apšvitų stabdomais bei skvarbiaisiais hadronais metu buvo sukurta nuotoliniu būdu valdoma matavimų sąranga ir pritaikyta radiacinių defektų tipų ir jų... [toliau žr. visą tekstą] / Electrically active defects are one of the main obstacles to produce high efficiency semiconductor based devices. Deep levels determine the non-radiative recombination processes and deteriorate efficiency of light emitting diodes, charge collection efficiency of radiation detectors and determine high power dissipation of the power devices. This work is addressed to material science and development of contactless measurement technologies for non-invasive defects characterization and identification within modern structures of Si, Ge and GaN by developing the non-destructive techniques. Contactless time resolved techniques for deep levels spectroscopy has been approved for evaluation of defects parameters within irradiated Si and implanted Ge structures. Peculiarities of recombination parameters have been revealed in Ge structures dependent on doping and irradiation. The methodology and instrumentation for the control of recombination parameters during irradiations by penetrative and stopped protons have been proposed, designed and approved. Evolution of densities and of species of the radiation defects during irradiation has been examined and models for fluence dependent variations of density of extended defects are proposed. An impact of dislocation networks on recombination properties has been revealed within strained thin-layered SiGe structures and epitaxial GaN layers. The models for explanation of the interplay of defects in these structures have been proposed in this... [to full text]
59

Cálculo do equilíbrio de fases em sistemas contendo hidrocarbonetos em fase gasosa com altos teores de CO2 e traços de água. / Phase equilibrium calculations for systems with hydrocarbons in gas phase with high content of CO2 and traces of water.

Danilo Pereira de Carvalho 02 September 2016 (has links)
Os grandes campos de petróleo offshore recentemente descobertos na camada pré-sal, localizada no sudeste do Brasil, representam um avanço significativo da participação brasileira nas reservas mundiais de hidrocarbonetos, que ainda são a principal matriz energética mundial. Nesse cenário, torna-se importante o desenvolvimento da produção desses campos. Um dos principais desafios tecnológicos da exploração desses campos é o processamento do gás natural associado, que possui altos teores de dióxido de carbono CO2. Esse contaminante deve ser separado para possibilitar a injeção no reservatório e/ou o escoamento desse gás através de dutos submarinos, dadas as restrições na legislação ambiental. Nas plantas de processamento instaladas no convés de grandes embarcações, são previstas instalações para a separação do CO2 e a remoção de umidade do gás a fim de evitar a formação de hidratos e a corrosão acentuada das linhas de escoamento, pois tanto a injeção quanto a exportação do gás são realizadas em condições de pressão e temperaturas extremas. Nesse contexto, o conhecimento acurado das condições em que se forma uma fase aquosa líquida é importante para garantir a viabilidade técnica e de segurança dessas operações. Considerando a relevância do assunto e as limitações da literatura para os cenários enfrentados no pré-sal brasileiro, esse trabalho tem o objetivo de fazer um estudo abrangente do equilíbrio de fases em sistemas contendo hidrocarbonetos em fase gasosa com altos teores de CO2 e traços de água, visando à obtenção de modelo para cálculo do ponto de orvalho da água. O uso de modelos rigorosos baseado na teoria dos fluidos associativos (PC-SAFT) mostrou-se adequado para o cálculo das condições de saturação em amplas faixas de pressão e temperatura. Com base em dados experimentais publicados foi possível fazer um ajuste preciso dos parâmetros de interação binária da equação de estado PC-SAFT. Como resultado, obteve-se um modelo capaz de descrever o comportamento de fases em misturas de hidrocarbonetos com composição próxima das encontradas no pré-sal brasileiro. / The giant offshore petroleum fields recently discovered in the pre-salt layer on the southeast of Brazil represent a significant increment in the Brazilian share of the global hydrocarbon reserves, which is still the most important energetic matrix. In this scenario, the development of production for these petroleum fields becomes important. One of the main technological challenges posed by these fields is the processing of the associated gas, which contains high amounts of carbon dioxide (CO2). Due to environmental laws, this contaminant must be separated to allow the injection back into the reservoir and/or the gas flow through subsea pipelines. The gas processing plants installed on large vessels comprise facilities that remove CO2 and moisture from natural gas, to prevent hydrate formation and severe corrosion throughout the pipelines, as both gas injection and gas exportation are performed in extreme pressure and temperature conditions. Thus, the accurate knowledge of conditions in which aqueous liquid phases are formed is important to ensure the technical viability and operational safety of these operations. Considering the relevance of this subject and the limitations of published works for the Brazilian pre-salt scenario, this work presents a comprehensive study on the phase equilibrium in systems with hydrocarbons in gas phase with high content of CO2 and traces of water, aiming at developing a model to calculate the dew point of water. The use of a rigorous method based on the associating fluid theory (PCSAFT) has shown to be appropriate to calculate the saturation condition for a large range of pressure and temperature. Based on the experimental data published, the fitting of the binary interaction parameter from the PC-SAFT equation of state was carried out. The resulting model was able to describe the phase behavior of hydrocarbon mixture with composition similar to those found in the Brazilian pre-salt.
60

Mecanismos envolvidos na citotoxicidade de uma ditiolpirrolona obtida de Streptomyces sp. isolado da AscÃdia Eudistoma vannamei / Mechanisms involved in cytotoxicity ditiolpirrolona obtained from a Streptomyces sp. isolated from Squirt Eudistoma vannamei

Paula AraÃjo de Abreu 09 April 2013 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / O cÃncer à caracterizado por ser um conjunto de doenÃas que envolve crescimento descontrolado, surgimento e espalhamento de cÃlulas anormais, e à considerada uma das principais causa de morte por doenÃa no mundo. AscÃdias e microorganismos marinhos sÃo profÃcuos produtores de substÃncias com atividade citotÃxica e antitumoral. Estudos preliminares com a ascÃdia Eudistoma vannamei, endÃmica do nordeste brasileiro, identificaram uma potente atividade anticÃncer de seu extrato e, a partir dele, isolaram-se esteuroporinas inÃditas. Curiosamente, tais molÃculas sÃo comumente produzidas por bactÃrias. No presente trabalho, os extratos dos microorganismos isolados da ascÃdia foram testados quanto a sua citotoxicidade e o mais potente deles foi selecionado e indentificado como actinomiceto pertencente ao gÃnero Streptomyces sp. A partir da purificaÃÃo desse extrato, foi isolada uma ditiolpirrolona citotÃxica que apresentou valores de concentraÃÃo inibitÃria mÃdia variando de 1,05 a 6,39 μM, em diferentes linhagens tumorais. Estudos realizados em cÃlulas de carcinoma prostÃtico humano metastÃtico indicaram que a ditiolpirrolona causou despolarizaÃÃo mitocondrial e induziu o aparecimento de figuras mitÃticas, apÃs 24 e 48 horas de tratamento. AlÃm disso, detectou-se alteraÃÃo no ciclo celular, como atraso nas fases final do ciclo, S e G2/M. A ditiolpirrolona alterou a expressÃo de algumas proteinas relacionadas ao ciclo celular e principalmente à citocinese, como Prc1, Plk-1 e RhoA, tais proteÃnas estÃo diretamente envolvidas com a formaÃÃo do anel contrÃtil, imprescindÃvel para a conclusÃo da divisÃo celular / Ascidians and marine microorganisms are prolific producers of cytotoxic and antitumor compounds. As part of a study to examine Brazilian species, we examined microbiota associated with ascidian, Eudistoma vannamei as potential sources for active natural product leads Earlier revisions with this specie showed a potent anticanceractivity of its extract; and two unpublished staurosporines were isolated. Curiously, these classes of compounds are generally produced by bacteria. So, in order to evaluate the biomedical potential of these compounds the microbiota associated to the ascidian Eudistoma vannamei was investigated. From this effort we isolated a number of bacterial strains and after screening for cytotoxicity using a panel of tumor cell lines, we identified a Streptomyces sp.,that presented significant bioactivity. Using bioactivity fractionation, we identified the active compound as, dithiolopyrrolone N-(4,5-dihydro-5-oxo-1,2- dithiolo[4,3-b]pyrrol-6-yl)-N-methyl-formamide also know as VD846. The compound presented IC50 values ranging from 1.1 to 6.4 μM across a panel of cell lines. Further biological studies, indicated that this compound induced cell cycle arrest during mitosis, an observation that was confirmed by evaluating the effects on a series of cell lines using mitotic index analyses, flow cytometry, and confocal microscope. Western blot analyses indicated that cells treated with VD846 resulted in reduced expression of Plk1 and RhoA, proteins that are necessary for cleavage furrow assembly and exit from cytokinesis.

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