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Delgoda, Rupika. "A study of arylamine N-acetyltransferase from Salmonella typhimurium." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302221.
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Lhoumaud, Priscillia. "Rôle de l'histone méthyl-transférase dMes-4 dans l'expression des gènes, la pause et l'épissage." Toulouse 3, 2014. http://www.theses.fr/2014TOU30096.
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Les protéines qui se fixent aux séquences dites 'insulatrices' sont appelées les 'IBPs' (pour 'Insulator Binding Proteins'). Ces facteurs réguleraient de nombreux gènes via leur rôle dans l'organisation de la chromatine. Une hypothèse de travail est que cette fonction des IBPs reposerait sur leur capacité à ouvrir la chromatine localement, favorisant ainsi le recrutement de facteurs impliqués dans la régulation des gènes. Lors de mon travail de thèse, j'ai tout d'abord identifié l'enzyme de méthylation d'histones (HMT), dMes4, comme un partenaire structural et fonctionnel important des protéines insulatrices BEAF-32/dCTCF. Ainsi, mes résultats ont montré que déplétion de dMes4 récapitulait les défauts d'expression obtenus après déplétions des IBPs, démontrant son rôle prépondérant en tant que co-facteur des IBPs. DMes-4 est la seule enzyme capable de di-méthyler l'histone H3 sur la lysine 36 (H3K36me2) chez la Drosophile, une modification d'histone qui jouerait un rôle déterminant dans le recrutement des complexes d'acétylation des histones (HATs) qui permettent l'ouverture de la chromatine. Mes recherches ont par ailleurs souligné le rôle prépondérant des IBPs dans le recrutement de cette HMT, permettant ainsi l'ouverture de la chromatine aux promoteurs de gènes. De plus, j'ai montré que ce mécanisme dMes-4 dépendant était requis pour le recrutement de l'activateur transcriptionnel DREF, un facteur clé dans la régulation des oncogènes. DREF active l'élongation de la transcription par l'ARN polymérase II qui est couplée à la tri-méthylation H3K36me3 par l'enzyme dHypB. De façon intéressante, la tri-méthylation est requise dans le recrutement des facteurs d'épissage et mes résultats ont montré que la marque H3K36me2 servirait dans ce contexte à prédéfinir un état chromatinien 'compétent' pour que l'activation transcriptionnelle soit couplée à la bonne maturation des ARNs. Un deuxième volet de mes travaux a permis de caractériser la fonction de dMes-4 et de dHypB dans la transition entre les étapes de " pause " et d'élongation de l'ARN polymérase II, via le recrutement du complexe P-TEFb, qui est nécessaire à la bonne maturation de l'ARN polymérase II et à la dissociation concomitante du facteur de pause appelé NELF. Mes résultats montrent que NELF servirait de point de contrôle permettant de coupler l'élongation à l'épissage et la maturation des transcrits. Aussi, ce couplage dépendrait notamment de la fonction dMes-4-dépendante dans le recrutement de P-TEFb et de celle de NELF dans le contrôle de la 'maturation' de l'ARN polymérase II. Mes résultats suggèrent que ces défauts de maturation seraient dus à l'incapacité de la forme immature à recruter dHypB, entraînant ainsi des défauts d'épissage dépendants de H3K36me3. Mes travaux permettent ainsi de mieux comprendre le rôle de la pause dans la maturation des ARNs, via les HMTs dMes-4/dHypBThe Drosophila insulator-binding proteins (IBPs) Beaf32/dCTCF regulate gene expression, through mechanisms that may involve their role in chromatin organization. One hypothesis is that chromatin insulators may lead to open chromatin locally, thereby recruiting factors involved in transcriptional activation. During my PhD, I have identified a key histone modifier, dMes-4, as a novel co-factor of IBPs involved in chromatin accessibility, which specifically co-regulates hundreds of genes flanked by Beaf32/dCTCF. DMes-4, the only H3K36me2 histone methyltransferase in Drosophila, may play a key role in the recruitment of Histone acetyltransferases (HATs) leading to a chromatin opening. Our results show that dMes-4 is recruited at gene promoters through IBPs, thereby opening chromatin locally for the recruitment of the transcriptional activator DREF. Such transcriptional activation is involved in oncogene activation. Our results show that DREF triggers RNAPII elongation concomitantly with the trimethylation of H3K36 (H3K36me3) by dHypB, thereby allowing H3K36me3-dependent RNA splicing. Our work highlights a key role of IBPs/dMes-4 in presetting chromatin for transcriptional activation and proper RNA splicing. A second part of my Ph. D. Work was to characterize the respective roles of dMes-4 and dHypB in the "switch" from RNAPII pausing to transcription elongation, through the recruitment of the complex P-TEFb. We show that P-TEFb is required for the maturation of RNAPII, which is under the control of the paused factor NELF. My data show that NELF may serve as a "checkpoint" coupling RNAPII maturation with RNA splicing. This checkpoint may involve both dMes-4 in recruiting P-TEFb, and of NELF in preventing the release of RNAPII before its "maturation". Our data further show that NELF depletion leads to splicing defects due to the impaired recruitment of dHypB on such immature RNAPII, leading to defects in H3K36me3 deposition. As such, my work highlights a key function of the HMTs dMes-4/dHypB and of NELF-mediated RNAPII pausing in RNA maturation
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Deml, Christoph. "Analyse und Modellierung des DMOS-Transistors." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969618816.
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Deml, Christoph Hoffmann Kurt. "Analyse und Modellierung des DMOS-Transistors." Neubiberg Universitätsbibliothek der Universität der Bundeswehr, 2008. http://d-nb.info/998614890/34.
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Faigle, Christopher Tyler. "DMS-Splines and radiosity." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624727.
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Zupac, Dragan. "Radiation-induced mobility degradation in DMOS transistors." Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186456.
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Effects of radiation-induced interface-trapped charge and oxide-trapped charge on the inversion-layer carrier mobility in double-diffused metal-oxide-semiconductor (DMOS) power transistors are investigated. Interface-trapped charge is more effective in scattering inversion-layer carriers than oxide-trapped charge. However, the effects of oxide-trapped charge must be taken into account in order to properly describe the mobility behavior. An effective approach to detecting effects of oxide-trapped charge and separating these effects from effects of interface-trapped charge is demonstrated. Detection is based on analyzing mobility data sets which have different functional relationships between the two trapped charge components. These relationships may be linear or nonlinear. Separation of effects of oxide-trapped charge and interface-trapped charge is possible only if these two trapped charge components are not linearly dependent. A significant contribution of oxide-trapped charge to mobility degradation is demonstrated and quantified. Effects of oxide-trapped charge may be dominant in non-hardened DMOS transistors irradiated at relatively high dose rates. In addition, DMOS devices have been irradiated at room temperature and mobility measurements performed at room temperature and at 77 K to analyze mobility degradation due to the same density of radiation-induced defects at these two different temperatures. Radiation-induced mobility degradation is more pronounced at 77 K than at room temperature, due to increased relative importance of Coulomb scattering from trapped charge when phonon scattering is significantly reduced. Effects of oxide-trapped charge on mobility are more pronounced at cryogenic temperatures than at room temperature.
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Hung, Merit Y. (Merit Yi). "Double diffused (DMOS) FETs for analog applications." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/13698.
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Angel, Mattias, and Albert Berggren. "Regionala DMOs marknadsföring och sociala mediers påverkan." Thesis, Mittuniversitetet, Institutionen för ekonomi, geografi, juridik och turism, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-39247.
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Destination management organizations (DMOs) är organisationer som ofta är uppbyggda av två eller flera medlemsorganisationer. En huvudsaklig uppgift som DMOs har är att marknadsföra destinationen. Sociala medier är något som förändrat sättet många organisationer bedriver sin marknadsföring på. Kommunikationen har gått från statisk envägs, alltså från den som producerar budskap till den som konsumerar, till mer dynamisk tvåvägskommunikation där relationer, samarbete och kommunikation mellan de två parterna kommit att bli allt viktigare. Vi undersöker i den här uppsatsen hur svenska regionala DMOs använder sig av sociala medier i sitt marknadsföringsarbete. Empirin har samlats in genom kvalitativa, semistrukturerade intervjuer med personer som arbetar med marknadsföring vid fyra svenska regionala DMOs. Detta har kombinerats med en analys av berörda DMOs respektive sidor på de sociala medierna Facebook och Instagram. Resultaten visar att de olika organisationerna har både likheter och skillnader i hur de operativt och strategiskt använder sig av sociala medier i marknadsföringssyfte.Destination management organizations (DMOs) are usually structured by two or more member-organizations. One of the main tasks for a DMO is to market the destination. Social medias have changed the way a lot of organizations manages their marketing. Communication has gone from a static one directional, from the producer to the consumer, to a more dynamic two-way communication where the interaction between the two parts has become more important. In this paper we examine how swedish regional DMOs use social medias in their marketing. The empirical data has been gathered by qualitative semi-structured interviews with persons who work with marketing at four different swedish regional DMOs. This has been combined with analysis of the concerned DMOs social media pages on Facebook and Instagram. The results show that the different organizations have both similarities and differences in their strategic and operative use of social media in marketing efforts.
2020-06-08
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Ito, H., D. Suzuki, Y. Yokochi, S. Kuroda, M. Umemiya, H. Miyasaka, K.-I. Sugiura, M. Yamashita, and H. Tajima. "Quasi-one-dimensional electronic structure of (DMET)_2CuCl_2." The American Physical Society, 2005. http://hdl.handle.net/2237/7127.
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Schepp, Oliver. "Simulations- und Meßmethoden zur Bestimmung der Temperatur von LeistungsMOSFETs /." Düsseldorf : VDI-Verl, 1998. http://www.gbv.de/dms/bs/toc/251116484.pdf.
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Adolph, Daniela. "Zunahme der renalen Quecksilberausscheidung durch DMPS bei chronischer Quecksilbervergiftung." Diss., lmu, 2007. http://nbn-resolving.de/urn:nbn:de:bvb:19-79299.
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Adam, Banafscheh. "DMPS und Dimercaprol in der Therapie der akuten Arsenintoxikation." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972308113.
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Lundén, Jenny. "Atmospheric DMS in the High Arctic." Doctoral thesis, Stockholms universitet, Meteorologiska institutionen (MISU), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-38178.
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During the Arctic summer when the anthropogenic influence is limited, the natural marine source of sulfur in the form of gas-phase dimethyl sulfide viz. DMS(g), is of great importance for cloud formation. The harsh environment of the Arctic makes it difficult to perform in situ measurements of DMS(g) and hence regional model simulations can serve as a complement to increase our understanding of DMS related processes in the Arctic. In this thesis a regional scale meteorological forecast model, extended with DMS(g) calculations, is used to provide a consistent three-dimensional time evolving picture of DMS(g) over the pack-ice region. The analysis focus on meteorological aspects on the horizontal and vertical distribution of DMS(g). Our results show that the amount of DMS(g) over an oceanic source region alone does not determine concentration found over the pack-ice, the prevailing wind also exerts a large influence on the horizontal DMS(g) distribution. The modeled DMS(g) concentrations are advected in plumes in over the pack-ice, which, in combination with the photo-chemical decay, explain the large observed temporal variability of DMS(g) over the pack-ice. The modeled vertical structure show episodes with DMS(g) maxima well above the local boundary layer. Also shown is that DMS(g) maxima can be formed adjacent to frontal zones. In the presence of turbulence DMS(g) can be mixed downwards into the local boundary layer and aid growth to local particles and hence contribute to cloud formation in the boundary layer.At the time of the doctoral defense the following papers were unpublished and had a status as follows: Paper 1: Manuscript. Paper 2: Manuscript. Paper 4: Manuscript.
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Lundén, Jenny. "Atmospheric DMS in the High Arctic." Stockholm : Department of Meteorology, Stockholm University, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-38178.
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Diss. (sammanfattning) Stockholm : Stockholms universitet, 2010.At the time of the doctoral defense the following papers were unpublished and had a status as follows: Paper 1: Manuscript. Paper 2: Manuscript. Paper 4: Manuscript.
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Elbashiri, Ali. "Distributed Marking System (DMS), cORBA implementation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0007/MQ45367.pdf.
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Žáček, Jan. "Pilotní zavádění DMS v bankovním prostředí." Master's thesis, Vysoká škola ekonomická v Praze, 2014. http://www.nusl.cz/ntk/nusl-202082.
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The diploma thesis focuses on the analysis of a document management system (DMS) pilot implementation in the environment of a Czech bank. The thesis is divided into three parts; the first part is theoretical and remaining two parts are practical (analytical). The theoretical part is devoted to summarization of basic theoretical knowledge in the field of DMS and in a pilot deployment of information systems. The second part describes the EMC xCP 2.1 platform and evaluates its advantages and disadvantages compared to competing products. The third part describes the technological implementation and deployment of a new DMS pilot solution in a bank. Further it analyzes and describes the follow-up activities and related projects that increase the DMS usability in a real business applications. The diploma thesis concurrently focuses on the business requirements analysis including constrains of a new solution deployment, as well as the DMS technological aspects description and the solution design. The author of this thesis has been working as an analyst in the IT company and has been in a long-term cooperation with the DMS team in the bank. The motivation for choosing this topic is to make a summary and clarification of knowledge gained on projects in the the bank and to take an advantage of it in the future cooperation.
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Honkomp, Tina [Verfasser]. "Intraokulare Druckerhöhung und post-DMEK Glaukom / Tina Honkomp, geb. Wolf." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2018. http://d-nb.info/1172206031/34.
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Fokkema, Mark. "City branding on Instagram: DMOs and their usage of affordances." Thesis, Uppsala universitet, Institutionen för informatik och media, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-305446.
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Technological developments such as social media have created challenges for DMOs (destination marketing organisations or destination management organisations). DMOs are trying to keep up with development of new social media platforms including Instagram. Academic literature shows that there is very little known about the usage of Instagram by DMOs. Research on this topic is still in its infancy. This thesis aims to find out how Leeuwarden and Amsterdam, two cities in the Netherlands, are utilising Instagram by using affordances approaches of Kietzmann et al. and Spector. A qualitative case study, as well as a content analysis and interviews provide insight in DMOs usage of Instagram affordances, which is the purpose of this thesis. Findings show that both Leeuwarden and Amsterdam mostly use similar ways in utilising the affordances by Kietzmann et al. and Spector. The honeycomb model by Kietzmann et al. shows that the affordances of Instagram mainly focus on sharing, identity and relationships. Instagram does in a very limited way focus on groups. Spector’s affordances show that collaboration, interaction and creativity are most important. Reflection, dialogue, organisation and inquiry are not important.
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Morales, Jose I. "Tactical DMS : a global broadcast service option /." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1996. http://handle.dtic.mil/100.2/ADA311435.
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Thesis (M.S. in Systems Technology [Command, Control and Communications (C3)]) Naval Postgraduate School, June 1996.Thesis advisor(s): D.v.Z Wadsworth, R. Buddenberg, Carl R. Jones. "June 1996." Includes bibliographical references. Also available online.
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Caruana, A. "DMS and DMSP production by marine dinoflagellates." Thesis, University of East Anglia, 2010. https://ueaeprints.uea.ac.uk/25594/.
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Smith, Lucille Lakier. "The role of inflammation in delayed muscle soreness (DMS) and the effects of indomethacin on DMS and perceived exertion." Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/71190.
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PART I: MARKERS OF INFLAMMATION IN DELAYED MUSCLE SORENESS
Fifty-five untrained males were assigned to an experimental (E) or a control group (C), to re-examine the concept that DMS represents an acute inflammatory response. Subjects were assigned to receive either Indocin (Id; 100 mg per day) for 2 days prior to the treatment and a placebo (P) for 2 days after (Id-P); or the reverse combination (P-Id); or Id for- 4 days (Id-Id); or placebo (P-P). On the treatment day, to induce DMS, E subjects performed 30 min of bench-stepping with one leg leading throughout; C subjects rested for 30 min. Immediately before and after stepping/resting, all subjects used their right and left leg to perform 19 maximal and 15 submaximal repetitions on the Cybex II. Blood samples were collected -5 min before, immediately after bench stepping (0 h), 2 h after and 24, 48 and 72 h, to evaluate WBC. DMS was also monitored 0, 24, 48 and 72 h. All E subjects experienced a significant amount of DMS (p<.01) which peaked at 48 h after exercise (E=7.58 ± .79 vs 0 for C, X±SEM); however, no significant differences in soreness perception were observed between drug and placebo groups. Total WBC count ( cells/mm³ ) was significantly greater at 0 h (8,340±380) than at -5 min (6,699±365) for both E and C; this increase was most likely a response to Cybex exercise. At 2 h there was a significant increase in total WBC count for E ( 9,603±389) and no change for C ( 8,336±273}. Neutrophils increased significantly at 2 h for E only (6,428±375 vs 4,988±261 for C}. Bench-stepping leads to increases in DMS and increases in WBC count, particularly in neutrophils, 2 h after stepping; this data suggests that inflammation is involved in DMS.
PART II: EFFECT OF AN ASPIRIN-LIKE DRUG ON PERCEIVED EXERTION DURING BENCH STEPPING
The object of this study was to determine whether perceived exertion (RPE) for the limb performing predominantly positive work was significantly greater than for the limb performing predominantly negative work, during 30 min of bench stepping. A second objective was to determine the effects of indomethacin (Id) on RPE. Thirty-nine males were randomly assigned to a drug (Id) or placebo (P) group and administered 150 mg indomechacin or placebo, beginning 36 h prior to stepping. Results indicated no significant differences between RPE for "concentric" and "eccentric" limbs of the P group inspite of the fact that the metabolic demand of the "concentric" limb was much greater. Indomethacin did not significantly alter RPE during stepping however, when RPE scores were totaled over the entire bench stepping period, the Id condition was associated with a greater (p < .01) psychological cost for the "concentric" leg effort as compared to P; this indicated that indomethacin might alter effort sense related to concentric contractions.Ph. D.
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Schwinde, Jan-Hendrik [Verfasser], Gerd [Gutachter] Geerling, and Lars [Gutachter] Wojtecki. "Langzeitergebnisse nach Descemet-Membran Endothel Kerato-plastik (DMEK) und Triple-Descemet-Membran Endothel Keratoplastik (Triple-DMEK) im Vergleich / Jan-Hendrik Schwinde ; Gutachter: Gerd Geerling, Lars Wojtecki." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2019. http://d-nb.info/1188017888/34.
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Lewis, Annabelle Jane. "The control and function of DMRs in the Igf2-H19 locus." Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619942.
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Salomão, Wellington Fioravante. "Microencapsulação de dimetil dissulfeto (DMDS) por spray drying e spray congealing." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/60/60137/tde-29102012-141155/.
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O dengue e o dengue hemorrágico são considerados como as arboviroses mais importantes do ponto de vista da saúde pública além de serem também as mais disseminadas. O greening ou huanglongbing (HLB), por sua vez, é uma doença de difícil controle e rápida disseminação que afeta seriamente a produção de citros no mundo todo. É considerada a pior doença de citros da atualidade pois não tem cura e leva ao declínio e morte das árvores em alguns anos. O DMDS é um composto sulfúrico volátil derivado de plantas e que tem despertado um crescente interesse devido a sua comprovada atividade repelente e inseticida além de ação nematicida e disinfectante do solo. Visando oferecer uma alternativa para o controle de ambas as doenças, este trabalho teve como objetivo desenvolver um método de microencapsulação por spray drying e spray congealing para o dimetil dissulfeto (DMDS), visando a redução da sua volatilidade através de uma liberação controlada para o ambiente. Dessa forma, tornar-se-ia viável sua utilização como repelente, larvicida e inseticida no combate ao vetor do dengue além da sua utilização como repelente no controle do greening nas lavouras de citrus. Tentou-se a microencapsulação através de spray congealing utilizando enxofre como microencapsulante mas não se obteve sucesso devido as características térmicas do enxofre. Foram obtidas micropartículas de DMDS microencapsulado em goma arábica através da técnica de spray drying. As micropartículas e o processo de secagem foram caracterizados com relação ao rendimento de secagem, rendimento de microencapsulação, morfologia, teor de água residual, atividade de água, densidades aparente e compactada e propriedades de fluxo. Confirmou-se a possibilidade de microencapsulação de DMDS por spray drying e eficiência da goma arábica na retenção do mesmo. As partículas obtidas apresentaram boas propriedades de atividade de água, teor de água residual e densidade mas propriedades de fluxo que requerem melhoria. Foi feito também um estudo simplificado da viabilidade técnico-econômica da implantação de uma unidade de produção de DMDS microencapsulado. Esse estudo foi baseado no processo de microencapsulação estudado. Foram analisados diversos parâmetros econômicos e através destas análises verificou-se que a produção de DMDS microencapsulado pelo método utilizado seria economicamente viável.Dengue fever and dengue hemorrhagic fever are not only considered the most important arboviruses from public health standpoint but also the most disseminated ones. Greening or huanglongbing (HLB) is a citrus disease of difficult control and fast dissemination that affects citrus production all over the world. It is considered the worst citrus disease nowadays since it does not have a cure and it causes the decline and death of the trees in a few years. Dimethyl disulfide is a volatile sulphur compound derived from plants and that has aroused growing interest due to its proved repellence and insecticidal activity, soil disinfection and nematocidal properties. Therefore, this work aimed at developing a DMDS microencapsulation method via spray drying and spray congealing in order to decrease DMDS\' volatility through a controlled release to the environment and offer a control alternative to both diseases. This would make DMDS use as a repellent, larvicide and insecticide of dengue fever\'s vector and also its use in greening control as a repellent viable. We tried to microencapsulate the DMDS through spray congealing using sulfur as a microenpsulating agent but it was unsuccessful due to the thermal characteristics of sulfur. DMDS was microencapsulated in Arabic gum through spray drying. Drying yield, microencapsulation yield, morphology of the particles, residual water percentage, water activity, bulk and tapped density and flow properties were used to characterize the microparticles and the drying process. Feasibility of DMDS microencapsulation and Arabic gum efficiency in DMDS retention were confirmed. The microparticles presented good bulk and tapped density, residual water percentage and water activity properties though its flow properties requiring further improvement. A simplified technical-economical evaluation of a DMDS microencapsulation factory was also done. This evaluation was based on the studied microencapsulation process. Many economical parameters were analysed and those analyses showed that DMDS microparticles production using the studied method would be economically viable.
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Mužilová, Gabriela. "Návrh zavedeni DMS systému v organizační složce společnosti." Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2016. http://www.nusl.cz/ntk/nusl-241417.
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Master´s thesis focuses on company´s internal documentation and Document Management Systems. It presents a proposal for the project of SharePoint implementation in the selected organisational unit of a company, using the Cloud Computing technology. An assessment of risks, resulted from the project and especially from the Cloud Computing, leads to the essential part of this paper, to the proposal of security arrangements and solutions. The arrangements will be advised to the organisational unit considering the economic cost comparison with potential risks.
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Horník, Jiří. "Systémy pro správu dokumentů (DMS) ve státní správě." Master's thesis, Vysoká škola ekonomická v Praze, 2006. http://www.nusl.cz/ntk/nusl-7256.
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Práce charakterizuje systémy pro podporu správy dokumentů (DMS) a jejich využití v prostředí státní správy. Jsou popsány technologické i organizační aspekty práce s dokumenty v tomto prostředí. Speciální část je věnována legislativě, která hraje v prostředí státní správy velmi podstatnou roli. Praktické otázky jsou řešeny na základě případových studií z české praxe.
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Pedemonte, Sarrias Eduard. "Tècnica de Muraine per a DMEK: anàlisi comparativa amb la tècnica estàndard." Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/405259.
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La queratoplàstia endotelial de la membrana de Descemet (DMEK) és la tècnica d'elecció actual per al tractament de l’edema corneal irreversible. Després que Melles la desenvolupés el 2006, Muraine va proposar el 2013 una tècnica alternativa per a la dissecció i implantació de l’empelt. Aquesta tècnica aportava dues novetats: la hidrodissecció amb trepanació parcial i curvatura corneal invertida del teixit donant i el plegament de l’empelt amb l'endoteli a la seva cara interna, que afavoria la protecció de l’endoteli i la tendència natural de l’empelt a desplegar-se a la cambra anterior del receptor.
L’objectiu d’aquesta tesi doctoral és comparar la tècnica de Muraine amb la tècnica estàndard analitzant-ne la densitat de cèl·lules endotelials (DCE) i agudesa visual (AV) postoperatòries, els temps quirúrgics i les complicacions intraoperatòries i postoperatòries. Es va dur a terme un estudi de cohorts prospectiu observacional multicèntric en la pràctica clínica habitual a l’Hospital Universitari MútuaTerrassa i l’Institut de Microcirurgia Ocular. El seguiment postoperatori va ser de sis mesos, amb controls com a mínim l’endemà, al cap d’una setmana i al cap d’un, tres i sis mesos de la cirurgia.
Es van incloure 27 ulls de 20 pacients al grup de la tècnica Estàndard i 42 ulls de 40 pacients al grup intervingut amb la tècnica Muraine. La DCE als sis mesos va ser de 1488 (1337-1679) cèl·lules/mm2 al grup Estàndard i de 1170 (734-1614) cèl·lules/mm2 al grup Muraine (P=0.10). L’AV mitja als sis mesos va ser de 0.89 al grup Estàndard i 0.79 al grup Muraine, en l’escala decimal (P=0.19). Al voltant del 80% van assolir una AV de 0.5 o més i el 50-70%, 0.8 o més.
Es va observar que la DCE i el percentatge de pèrdua de DCE al mes de la cirurgia eren equivalents als de la tècnica estàndard. El percentatge de pèrdua de DCE als sis mesos va ser superior amb la tècnica de Muraine, si bé la DCE va ser clínicament comparable. L’AV assolida als sis mesos va ser equivalent. La tècnica de Muraine va ser tan segura com la tècnica estàndard per a l’obtenció de l’empelt. La incidència de complicacions intraoperatòries amb l’empelt preparat amb la tècnica de Muraine en ulls amb facoemulsificació no complicada no va ser estadísticament superior. La dissecció de l’empelt amb la tècnica de Muraine va ser més lenta. El desplegament, per contra, va ser lleugerament més ràpid. Totes dues tècniques van tenir una taxa elevada de supervivència de l’empelt. La complicació postoperatòria més freqüent en ambdós grups va ser l’edema macular quístic. Els empelts dissecats amb la tècnica de Muraine van tenir una major incidència de necessitat de reinsuflació.Descemet’s membrane endothelial keratoplasty (DMEK) is the current gold standard treatment for irreversible corneal oedema. After Melles developed this technique in 2006, Muraine proposed in 2013 an alternative technique for the dissection and implantation of the graft. Its main contributions were: hidrodissecting the graft from a partially trephined, inverted donor tissue, and folding the graft over the endothelial side, which favoured the protection of endothelial cells and the graft’s natural tendency to unfold in the receptor’s anterior chamber. The purpose of this doctoral thesis is to compare Muraine’s technique to the Standard through analysis of the postoperative endothelial cell density (ECD) and visual acuity (VA), surgical time, and intraoperative and postoperative complications. An observational, multicentric, prospective, cohorts trial was carried out in Hospital Universitari MútuaTerrassa and Institut de Microcirurgia Ocular in a daily praxis basis. There were follow-up controls over the six months following the surgery, at least at day one, first week and first, third and sixth months. Twenty-seven eyes from 20 patients were included in the Standard technique group. Forty-two eyes from 40 patients were included in the Muraine’s technique group. The ECD at six months was 1488 (1337-1679) cells/mm2 for the Standard group and 1170 (734-1614) cells/mm2 for Muraine’s group. The mean VA at six months was 0.89 for the Standard group and 0.79 for Muraine’s group, in the decimal scale (P=0.19). Around 80% of the eyes reached a VA of 0.5 or higher and 50-70%, 0.8 or higher. The ECD and the percentage of ECD loss with Muraine’s technique at the first month after surgery were equivalent to the Standard technique’s. The percentage of ECD loss at six months was higher with Muraine’s technique, although the ECD was clinically comparable. The VA achieved at six months was equivalent. Muraine’s technique was as safe as the Standard technique for the graft dissection. The incidence of intraoperative complications among the eyes with uncomplicated phacoemulsification was not statistically higher with Muraine’s technique. The graft dissection with Muraine’s technique was slower. Conversely, the unfolding was slightly faster. Both techniques had a high graft survival rate. The most frequent postoperative complication in both groups was cystoid macular oedema. The grafts dissected with Muraine’s technique had a higher incidence of need for rebubbling.
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Zhu, Xianmin Elefant Felice. "The histone acetyltransferase Dmel\TIP60 Is essential for multicellular development in Drosophila /." Philadelphia, Pa. : Drexel University, 2007. http://hdl.handle.net/1860/2582.
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Friberg, Marika, and Linnea Häll. "En normativ studie av DMO’s destinationsmarknadsföring : Hur bör DMOs marknadsföra sina destinationer?" Thesis, Linnéuniversitetet, Institutionen för organisation och entreprenörskap (OE), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-49160.
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Den här uppsatsen behandlar fenomenet Destination Marketing Organisations och deras destinationsmarknadsföring. Syftet med studien har varit att komma fram till ett antal aspekter som destinationer och DMO bör fokusera på när de marknadsför sin destination. Detta har undersökts dels genom studerande av tidigare forskning och dels genom ett empiriskt fall, Destination Kalmar. De forskningsmetoder som har använts är innehållsanalys av deras marknadsföringsmaterial (hemsida och magasin) samt strukturerade intervjuer med personal på Destination Kalmar. Studien har resulterat i 14 aspekter som DMOs bör fokusera på när de marknadsför sin destination. Dessa aspekter berör främst vilka informationskanaler DMOs bör använda och på vilket sätt, hur de bör hantera säsongsproblematik på destinationen, samt hur DMOs bör hantera kundrelationer och lojalitet.
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Qian, Yihong. "DMAS : a Display Measurement and Analysis System with an object-oriented database /." This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06112009-063840/.
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Bouanane, Mohamed El Amine. "Conception et optimisation des composants DMOS latéraux haute tension en technologie RESURF." Toulouse 3, 1992. http://www.theses.fr/1992TOU30238.
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Une des solutions prometteuses pour la realisation des interrupteurs dans les circuits integres de puissance est le transistor lateral double diffuse mos utilisant la technique resurf (reduced surface field). Les avantages de ce dernier sont: (a) simplicite de mise en oeuvre, (b) excellente tenue en tension, (c) auto-isolation, (d) sa compatibilite avec la technologie des composants basses tensions (cmos, bipolaire ou bicmos). Cependant deux problemes majeurs interviennent dans l'optimisation de ce dispositif: (a) la resistance a l'etat passant ron trop elevee, (b) sensibilite importante de la tenue en tension vis-a-vis des parametres technologiques. Pour pallier a ces inconvenients nous proposons d'utiliser: (a) un surdopage en surface de la structure, (b) une passivation par une couche semi-resistive tel que le sipos. Les simulations numeriques bidimensionnelles montrent que l'utilisation conjointe de ces deux techniques permet d'obtenir une amelioration de la resistance ron qui s'evalue entre 40 et 60% ainsi qu'une desensibilisation importante au regard des tolerances technologiques. Les parametres geometriques (distance canal-drain, epaisseur de l'epitaxie et epaisseur de l'oxyde) et physiques (dopage de l'epitaxie, concentration et profondeur du surdopage) sont optimises afin d'obtenir la tenue en tension optimale de 400 volts. Les regles de conception ainsi definies ont permis la realisation des diodes ainsi que des transistors ldmos resurf utilisant le surdopage en surface et la passivation par du sipos
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Lundgren, Moa. "DMOs Strategies to Attract Tourists to Nature-Based Destinations in Norrbotten County : A qualitative study on DMOs usage of marketing strategies to endorse destinations concerned by nature-based tourism." Thesis, Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-79418.
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The tourism industry is one of the most thriving industries in the world and nature-based tourism is one of the most expanding sectors in the European tourism industry. However, destinations today have global substitutes which means a destination can easily be exchanged for another destination. Thus, destination market organizations have become a critical component in the tourism industry. While there is a growing interest for nature-based destinations due to international tourism and a growing awareness of environmental issues there is still a need to create a differentiation from the global competition. By setting up strategic plans and continuously market a destination, destination marketing organizations (DMOs) can attract tourist from distant markets. Therefore, the purpose with this report is to examine strategies that DMOs use when it comes to attract tourists to nature-based destinations. With the aim to fulfill the purpose of this study one research question of descriptive and exploratory kind were stated: “What strategies are DMOs using to attract tourists to nature-based destinations?”. A theoretical framework was conducted by reviewing scholarly journals which generated potential answers for the stated research question. Furthermore, the frame of reference provided the study with a theoretical foundation which was applied during the data collection as well as the data analysis. Methodologically, this study had a qualitative approach and was therefore collecting data through semi-structured and in-depth interviews with employees of different DMOs. The findings and conclusions show that the practical work done by a nature-based DMOs in a high degree follows existing previous research. Where the importance of having a clear market position, being able to segment an audience, as well as promote an appropriate message is of high concern for a DMO. Hence, it helps them to attract tourist to a nature-based destination.
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Vogt, Meike. "Marine production of DMS and its interaction with climate." Thesis, University of East Anglia, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492924.
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Pillans, Julian. "DMS and CDOM photochemistry in estuarine and coastal waters." Thesis, University of Newcastle Upon Tyne, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.435600.
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Kretzmer, Helene. "Methods for DNA Methylation Sequencing Analysis and their Application on Cancer Data." Doctoral thesis, Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-203416.
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The fundamental subject of this thesis is the development of tools for the analysis of DNA methylation data as well as their application on bisulfite sequencing data comprising a large number of samples. DNA methylation is one of the major epigenetic modifications. It affects the cytosines of the DNA and is essential for the normal development of cells and tissues. Unusual alterations are associated with a variety of diseases and, specially, in cancergeneous tissues global changes in the DNA methylation level have been detected. To sequence DNA methylation on single nucleotide resolution, the sequences are treated with sodium bisulfite before sequencing, whereby unmethylated cytosines are represented as thymines. Thus, specialized techniques are required to process and analyze these kind of data.
Here, the bisulfite analysis toolkit BAT is introduced, that is designed to facilitate an quick analysis of bisulfite treated DNA methylation sequencing data. It covers all steps of processing raw sequencing data up to calling of differential DNA methylation. At the begin of analysis, sodium bisulfite treated sequence data are aligned and DNA methylation rates for each covered cytosine in the reference genome are called. Subsequently, BAT integrates annotation data and performs basic analysis, i. e., methylation rate distribution plots and hierarchical clustering of the samples. In addition, calling of differentially methylated regions is performed and statistics of called regions are automatically created. Finally, DNA methylation and gene expression data integration is covered by the calculation of correlating regions.
Secondly, a novel algorithm, metilene, for the calculation of differentially methylated regions (DMRs) between two groups of samples is introduced. Existing methods are limited in terms of detection sensitivity as well as time and memory consumption. Our approach is based on a circular binary segmentation, using a scoring function to detect sub-regions that show a stronger difference between the mean methylation levels of two groups than the surrounding background. These sub-regions are tested using a two-dimensional Kolmogorov Smirnov test (2D-KS test) [Fasano 1987] for significant differences taking all samples of each group into account. The use of the non-parametric 2D-KS test allows to avoid assumptions about a background distribution. Furthermore, the two dimensions of the problem, i. e., (i) the detection of a region, such that (ii) the methylation rates of the samples in the groups are significantly different, are taken into account in a single test. The algorithm calls DMRs in sufficiently short time on single sample comparisons as well as on about 50 samples per group. Furthermore, it works on whole-genome bisulfite sequencing (WGBS) and reduced representation bisulfite sequencing (RRBS) data and is able so estimate missing data points from the methylation rates of other samples in the group. Benchmarks on simulated and real data sets show that metilene outperforms other existing methods and is especially suitable for noisy datasets often found for example in cancer analysis.
In the framework of this thesis, the previously introduced methods and algorithms are used to analyze a WGBS dataset of two different subtypes of germinal-center derived B-cell lymphomas and healthy controls. In both lymphoma subgroups genome-wide hypomethylation was found, with an exception for a specific type of promoter regions, i. e., poised promoters, that were frequently found to be hypermethylated. Using the previously presented algorithm, DMRs were called between the three entities. A strong enrichment of DMRs immediately downstream of the transcription start site was observed, indicating the regulatory relevance of this regions. The integration of gene expression data of the same samples, revealed that a considerable amount of the DMRs showed significant correlation between gene expression and DNA methylation. Finally, transcription factor binding sites and mutation data were combined with the methylation and expression data analysis. This identified strongly altered signaling pathways and cancer subtype specific genes. Furthermore, the data integration indicates that mutations and DNA methylation changes may act complementary to another.
Finally, findings from the lymphoma study regarding the hypermethylation of poised promoters in cancer were extended to a huge data set comprising a variety of cancers. We could show that the relation of DNA methylation at a small set of frequently poised regions with respect to the background methylation level is sufficient to classify almost all samples based on DNA methylation data from 450k BeadChips into cancer or non-cancer probes. In addition, we found that the increase in methylation co-occurs with upregulated gene expression of several poised promoter regulated genes in almost all fresh cancer samples, implying a de-poising of poised regions. This upregulated gene expression is in contrast to the silencing of those genes in cancer cell lines, indicating that the upregulated gene expression might be a temporary status and possibly contributes to cancerogenesis.
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Bergström, Joakim, Maria Lehtinen, and Mariel Svensson. "Successful Destination Branding? : A case study of DMOs in Brussels, Istanbul and Stuttgart." Thesis, Linköping University, Department of Management and Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-56666.
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Tourism is an important source of economic growth for destinations, which is why the interest for destination branding has grown in recent years. Meanwhile, Destination Marketing Organisations (DMOs) often struggle to promote their destination successfully. For instance, many stakeholders influence the perception of a destination and therefore it is difficult to create a coherent image. Some destinations have a more successful destination branding, which not only depends on their marketing methods but also the pre-requisites of the city. Hence, destination branding is a complex process where there is no standard solution. Therefore, three different destinations are used as a basis for the thesis; Brussels, Istanbul and Stuttgart. What can be learned from the marketing methods in these destinations? The purpose of this thesis is to examine the current market position of Brussels, Istanbul and Stuttgart as tourist destinations and their marketing strategies and methods used to promote the destinations. We will identify general recommendations on how to improve the destination branding, and propose specific recommendations to selected DMOs in the destinations.
Through the use of specific descriptive criteria, such as unique selling points (USPs), image and marketing channels, as well as the conducting of interviews with employees in higher administrative positions within the selected DMOs, the thesis aims at providing the reader with a deeper knowledge in the field of destination branding. The Tourist Area Lifecycle Model was used to analyse the destinations to understand their situation today and future possibilities and challenges in marketing the cities as tourist destinations. Moreover, the concepts of comparative and competitive advantages and the integrative model by Ritchie and Croutch was used to discuss the competitiveness of the destinations. The research shows that DMOs face problems, such as the lack of a coherent image, common goals, the coordination of activities between DMOs in different levels and cooperation between different stakeholders. These are areas that need attention from the DMOs in order to achieve successful destination branding and are included in the conclusion, which helps DMOs to improve their marketing methods in order to achieve success in the promotion of their destination.
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Napieralska, Malgorzata. "Modélisation du transistor V. DMOS pour simulation de circuits en électronique de puissance." Toulouse, INSA, 1991. http://www.theses.fr/1991ISAT0009.
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Un modele non lineaire du transistor v. Dmos de puissance a canal court dont les elements ne dependent que des donnees physiques et technologiques du composant est presente. Par analyse des regions actives de la structure du composant en vue de l'etude des regimes de commutation, ce modele est simplifie jusqu'a une topologie compatible avec le simulateur spice. Les procedures d'acquisition de ses parametres sont precisees ainsi que les tests de validation. Une bibliotheque informatique d'interrupteurs de puissance mos, destinee a la conception des circuits de puissance est cree par caracterisation des transistors (canal n et p) couvrant les gammes de tension 50v-1000v et de courant 2a-50a. Un modele unifie du v. Dmos est ensuite propose, qui necessite pour une technologie donnee deux parametres: calibre en tension et surface de puce du silicium. Un programme etabli, base sur l'environnement hypercard (macintosh) et couple avec spice permet d'etablir les modeles de produits catalogue et creer un modele pour de nouveaux composants. Cette modelisation est completee par la prise en compte de la temperature de cristal ainsi que diverses configurations de test. Un macromodele destine a rendre compte du comportement electrique sous contraintes radiatives des v. Dmos est aussi etabli et valide par comparaison entre les resultats experimentaux et la simulation. L'elaboration d'un montage de bras de pont a base de transistors mos, et sa simulation par spice permet enfin de mettre en evidence la validite du modele dans ce type d'application en prenant en compte des problemes lies a l'existence des elements parasites dans les circuits de l'electronique de puissance
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Kreschel, Martin. "Experimentelle und numerische Untersuchungen an Dehnungsmessstreifen (DMS) mit übereinanderliegenden Messgittern." Thesis, Universitätsbibliothek Chemnitz, 2002. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-200201252.
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In der experimentellen Beanspruchungsanalyse ist der Einsatz von Dehnungsmessstreifen alltäglich. Besonders DMS-Rosetten mit übereinanderliegenden Messgittern bieten eine "punktgenaue" Auswertung des Dehnungszustandes an der Oberfläche eines Bauteiles. In numerischen und experimentellen Analysen wurde die Dehnungsübertragung in die übereinanderliegenden Messgitterschichten untersucht. Desweiteren wurde die Wärmeentwicklung der DMS-Rosetten auf verschiedenen Bauteilen untersucht.
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Shema, Richard A. "Correlation of satellite-detected aerosol characteristics and oceanic dimethylsulfide (DMS)." Thesis, Monterey, California. Naval Postgraduate School, 1988. http://hdl.handle.net/10945/22994.
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Foldy, Mark S. "P-3 squadron transition to the Defense Message System (DMS)." Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/23745.
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Kreschel, Martin. "Experimentelle und numerische Untersuchungen an Dehnungsmessstreifen (DMS) mit übereinanderliegenden Messgittern." [S.l. : s.n.], 2002. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB10447108.
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Joos, Filip Alexius. "Implementace DMS v malých a středních firmách formou cloudového řešení." Master's thesis, Vysoká škola ekonomická v Praze, 2012. http://www.nusl.cz/ntk/nusl-162522.
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This thesis analyzes the field of Document Management Systems (DMS) in Small and medium enterprises (SME). To be more specific, it analyzes ways and opportunities of a transition of the actual company situation to a cloud solution realized by the means of outsourcing. Due to the fact that this transition consists of many steps, some of them are critical for a successful realization, those steps have to be precisely analyzed and afterwards a corresponding solution has to be proposed. This analysis describes in a detail all the connections, which may interfere with each other and which may also interfere with the whole transition. The goals of this thesis are mainly to provide a specialized analysis of the transition to the cloud DMS, analysis of available cloud solutions, their categorization and assessment, description of connections emerging from the use of the cloud DMS in Small and medium enterprises, description of impacts of realized solutions and finally a summary of the analysis into a compact unit designated to be used as a manual for cloud DMS implementation in the Small and medium enterprise.
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Mordenti, Eugenio. "Comportamento a fatica dell’acciaio Maraging MS1 prodotto tramite DMLS: influenza della posizione nella camera." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/16511/.
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L’obiettivo principale di questo studio è caratterizzare dei provini, prodotti mediante additive manufacturing, con il metodo DMLS (direct metal laser sintering), a fatica mediante prove di flessione rotante. I provini sono realizzati in Maraging steel, le cui caratteristiche meccaniche e composizione sono di seguito enunciate. I dati sperimentali ottenuti dalle prove vengono poi elaborati tramite la normativa ISO 12107-2012, per trovare la curva di fatica S-N, sia usando un’interpolazione lineare, che una quadratica, per confrontarle in modo da identificare quale metodologia approssima meglio i dati. E' inoltre utilizzata la normativa Dixon tramite uno stair-caise per trovare la tensione limite di fatica.
Un altro aspetto rilevante di questo elaborato è quello di analizzare il processo produttivo dei provini per capire quali sono i principali parametri che influenzano l’additive manufacturing e che conseguenze hanno sulla vita a fatica dei componenti realizzati. Per questo studio sono stati utilizzati tre set di provini (ogni set ha numerosità pari a 12) numerati dal 20 al 22. I set vengono trattati termicamente, lavorati alle macchine utensili, pallinati e sono analizzati nel dettaglio i processi appena citati. Legato a questi studi c’è il tentativo di trovare una correlazione tra la posizione di realizzazione dei provini in camera e la vita a fatica.
Infine si esegue un’analisi frattografica per capire meglio i meccanismi di innesco e propagazione delle cricche per fatica.
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Wardeh, Rima [Verfasser], and Walter [Akademischer Betreuer] Sekundo. "Long-Term Results after DMEK (Descemet’s Membrane Endothelial Keratoplasty) / Rima Wardeh ; Betreuer: Walter Sekundo." Marburg : Philipps-Universität Marburg, 2020. http://d-nb.info/1205879730/34.
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Dooley, Joan Mary 1961. "LEAD MOBILIZING ACTIVITY OF DMPS, DMSA, AND DMPA FOLLOWING ORGANIC AND INORGANIC LEAD EXPOSURE." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/275507.
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Baum, Keith Warren 1959. "ESD effects on the radiation response of low power vertical DMOS N-channel transistors." Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/277850.
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The effect of non-catastrophic human body model positive electrostatic discharge pulses on the radiation response of low power VDMOS N-channel transistors is explored. The effect of multiple pulses of HBM ESD is to cause a change in threshold-voltage shifts between stressed and non-stressed devices when exposed to Co₆₀ gamma radiation. This difference is due to the build-up of a space charge region next to the Si/SiO₂ interface. This space charge region reduces the net electric field across the gate oxide when biased with a positive voltage and thus reduces the formation of holes and interface traps. Therefore, the ESD stressed devices appear to be less sensitive to radiation.
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Ramosoeu, Makhabo Khabiso Ellen. "Characterisation and static behaviour of the DMLS Ti-6AI-4V for Bio-medical applications." Thesis, Bloemfontein: Central University of Technology, Free State, 2015. http://hdl.handle.net/11462/275.
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Thesis (M. Tech. (Engineering: Mechanical)) -- Central University of Technology, Free State,The Centre for Rapid Prototyping and Manufacturing (CRPM) at the Central University of Technology, Free State (CUT) manufactures implants using Electro Optical Systems (EOS) titanium Ti-6Al-4V alloy powder (further referred to as EOS Ti64 powder) by means of Direct Metal Laser Sintering (DMLS) process on the EOSINT M 270 machine. For this reason, there is a need to characterise and acquire knowledge of the basic properties of direct metal laser sintered EOS titanium Ti-6Al-4V alloy samples (further referred to as DMLS Ti64 samples) under static tensile loading in order to provide the CRPM with engineering design data. The first objective of this Master’s study is to acquire the characteristics of EOS Ti64 powder in order to ascertain its suitability in the DMLS process. Secondly, the study aims to assess tensile properties and elastic constants of DMLS Ti64 samples produced from the set process parameters of EOSINT M 270 machine. Thirdly, it is to investigate microstructures of DMLS Ti64 samples subjected to different heat treatment techniques which will eventually assist in the determination of a suitable heat treatment technique that will yield higher ductility. Finally, the study aims to validate the static behaviour of DMLS Ti64 samples subjected to the static tensile loading up to a yield point in order to determine failure due to yielding. The samples were manufactured at CRPM Bloemfontein. The metallographic examinations, heat treatment and the determination of mechanical properties were done at the CSIR in Pretoria. Optical Microscope (OM) and Scanning Electron Microscope (SEM) were used to determine microstructures of DMLS Ti64 samples while Energy Dispersive X-Ray (EDX) analyses were performed using SEM. The samples were heat treated at temperatures of 700, 1000 and 1100°C respectively, and subsequently either cooled with the furnace, air or were water quenched. The mechanical property tests included tensile, hardness and determination of elastic constants. The static behaviour of DMLS Ti64 samples under static tensile load up to a yield point was predicted and verified using ABAQUSTM Finite Element Analysis (FEA). The stress-strain curves from ABAQUSTM were interpreted using MDSolid program. The point of interest was Von Mises yield stress at 0.2% offset, in order to determine failure due to yielding. EOS Ti64 powder particles were spherical in shape and the alpha and alpha+beta phases were identified. As-laser sintered samples possess a very fine and uniform alpha case with islands of martensitic plates; samples were brittle and showed low levels of ductility with an average elongation of 2.6% and an area reduction of 3.51%. Ultrasonic test results showed that DMLS Ti64 samples have Young’s modulus of 115 GPa, Shear modulus of 43 GP, a bulk modulus of 109 GPa and Poisson’s ratio of 0,323 while the density was 4.4 g/cm3. Slow cooling of DMLS Ti64 samples from 1000 and 1100oC resulted in a microstructure constituted more by the alpha phase of lower hardness than those from 700oC and as-laser sintered samples. High hardness was obtained by water quenching. The water quenched samples showed martensitic transformation and high hardness when compared to furnace cooled samples. Beta annealing tailored a microstructure of as-laser sintered samples into a lamellar structure with different lath sizes as per cooling rate. Beta annealing improved ductility levels up to 12.67% elongation for samples furnace cooled for 4 hours and even higher to 18.11% for samples furnace cooled for 34 hours, while area reduction increased to 25.94% and 33.39%, respectively. Beta annealing conversely reduced yield strength by 19.89% and ultimate tensile strength was reduced by 23.66%. The calculated maximum Von Mises stresses found were similar to the FEA interpreted results. The average percentage error, without the stress concentration factor, was approximately 8.29%; with the stress concentration factor included, it was 0.07%. The small reaction forces induced in both x-axis and z-axis contributed to this error of 0.07% between the calculations and ABAQUSTM FEA results. Samples that were not heat treated fell outside the Von Mises criterion and failed due to yielding. This justified the brittleness found in the tensile test results where elongation and area reduction were 2.6% and 3.51% respectively. However, all samples that were heat treated fell within the Von Mises criterion. The objectives of this study were achieved; the mechanical properties were similar to those of standard specification for wrought annealed Ti-6Al-4V alloy for surgical implant applications and EOS GmbH manufacturer’s material data sheet. DMLS Ti64 samples must be beta annealed in order to attain higher levels of ductility. A recommendation was made to further investigate the effect of heat treatment on the other mechanical properties. Furthermore, detailed results of basic properties of DMLS Ti64 samples are provided in the appendices in chart format and were written on a CD disc.
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Jack, William Josiah. "A Six Sigma Approach to Implementing Conformal Cooling on Existing Processes in Injection Molding." OpenSIUC, 2017. https://opensiuc.lib.siu.edu/theses/2214.
Full textAbstract:
Injection molding is one of the most common methods of mass production. After injecting molten plastic into a mold, the heat must leave the plastic material, enter the mold steel, enter the coolant, and exit the mold. This heat flow is critical to producing high quality parts rapidly. As plastic cools, the plastic shrinks. Uneven cooling causes uneven shrinkage which can cause the part to warp from the resulting internal stresses or create sink marks on the part. Thus the effect of uneven cooling is lower part quality, both in appearance and in dimension. Standard or conventional cooling channels are straight-drilled holes arranged such that they intersect and connect to form a loop for coolant, typically water, to flow through. This allows the mold to act as a heat exchanger, transferring heat to the coolant and carrying heated coolant away from the mold. While standard cooling channels have been used widely in the injection molding industry for their manufacturability and proven results, other methods have been developed for creating molds with cooling channels of any desired path or shape. These channels, called conformal due to how they conform to the shape of the part, provide uniform cooling, eliminate or reduce the quality issues of warpage and shrinkage, and provide faster, more economical cycle times. Conformal cooling is cannot be produced only by subtractive manufacturing methods that remove material from raw stock but rather through additive or hybrid manufacturing techniques that add material in layers of powder, sections, or sheets. Bonded sheet layer mold inserts can be made of any size and are currently the only feasible way of making large, conformally-cooled molds. Presented is a Six Sigma approach for implementing conformal cooling in existing molds to achieve the benefits of higher part quality and fast cycle times. Feasibility considerations include existing mold features such as slides and ejectors, choice of channel diameter, and the cooling channel path. Cost justification considerations include assessing part quality cost impact through calculation of the costs of poor quality and assessing machine capacity as relates to cycle time. With the approach presented, an injection molding company should be able to assess feasibility and cost effectiveness of implementing conformal cooling on its molds.
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Jaime, Gustavo Carneiro. "Análise comparativa da resistência à corrosão eletroquímica da liga de Ti-6Al-4V e do aço inoxidável AISI316L obtidas por manufatura aditiva visando aplicações biomédicas /." Ilha Solteira, 2017. http://hdl.handle.net/11449/152091.
Full textAbstract:
Orientador: Ruis Camargo TokimatsuResumo: A procura por materiais, com compatibilidade e funcionalidade biológicas, que possam melhorar a qualidade da vida humana é constante, além da busca de processos de fabricação que atendam às necessidades de manufatura de artefatos de geometria complexa. Os artefatos de aço inoxidável são utilizados por possuírem uma boa biocompatibilidade, baixo custo de produção, mas podem liberar íons como o cobalto, que é carcinogênico. O uso de Ligas de titânio é uma boa alternativa, já que possuem uma maior resistência à corrosão e boa resposta biológica, porém, seu custo é muito elevado. Considerando esses aspectos, o presente trabalho foi realizado buscando estudar, comparativamente, as características de microdureza, microdesgaste e resistência à corrosão de artefatos manufaturados para aplicações biomédicas, aproveitando as características mecânicas da liga de aço inoxidável AISI316L, usado como substrato, com as características eletroquímicas apresentadas pela liga de titânio Ti-6Al-4V, usado como material de tratamento de superfície. A sinterização direta dos metais por laser (DMLS) foi o processo de manufatura escolhido por apresentar as características de fabricação desejadas. Os ensaios realizados foram o de microdureza Vickers, ensaio de desgaste microadesivo por esfera rotativa fixa (esfera-fixa) e para o comparativo da resistência à corrosão eletroquímica foram produzidas curvas de polarização potenciodinâmicas que forneceram os seguintes parâmetros: o potencial de corrosão, a... (Resumo completo, clicar acesso eletrônico abaixo)
Mestre
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Demir, Hakan. "Dimethyl Ether (dme) Synthesis Using Mesoporous Sapo-34 Like Catalytic Materials." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613471/index.pdf.
Full textAbstract:
In 21st century, researchers make great effort of finding a clean transportation fuel to
diminish the severe effects of conventional transportation fuel combustion such as global
warming and air pollution. Dimethyl ether is considered as a strong fuel alternative due to its
good burning characteristics and environmentally friendly properties. In order to produce
dimethyl ether, different synthesis routes and solid acid catalysts are being utilized. SAPO-34 is
an aluminophosphate based catalyst having moderate acidity. This property makes it a good
candidate for the synthesis of dimethyl ether. However, SAPO-34 has microporous structure
causing diffusion limitations.
The objective of this study is to synthesize, characterize mesoporous SAPO-34 like
catalytic materials and test the activity of them in methanol dehydration reaction. The benefit of
obtaining mesoporous structure is that the diffusion limitations can be eliminated.
Mesoporous SAPO-34 like catalysts were synthesized through hydrothermal synthesis
route. BET surface areas of these catalysts were 117-133 m2/g. All methanol dehydration
reactions were carried out at a space time of 0.14 s.g/cm3. By using mesoporous SAPO-34 like
catalysts, the highest methanol conversion was 48% obtained at 550°C with DME selectivity and yield values of 1 and 0.49, respectively. Since utilizing microporous SAPO-34 catalyst gave higher methanol conversion, 67%, at lower temperature, 250°
C, with dimethyl ether selectivity of around 1, mesoporous SAPO-34 like catalysts are not suitable for this reaction.