238 research outputs found
Evaluatie ARMAX E10-predictie model
No full textNa jaren van onderzoek en ontwikkeling is in 1986 op het Hydro Meteo Centrum (HMC) in Zeeland een tijdreeksmodel geïmplementeerd, waarmee m.b.v. aktuele golf- en windwaarnemingen deiningsvoorspellingen voor de zuidelijke Noordzee gegenereerd kunnen worden. De laagfrequente energie (E10) voorspellingen van dit ARMAX model zijn in principe gebaseerd op deiningsvoortplanting vanuit het noorden (Schilperoort, Poulisse en Wensink, zie Appendix I) en worden voornamelijk gebruikt om een optimaal toelatingsvoorschrift voor de toegangsgeulen van de Rotterdamse havens te verkrijgen. Verder worden ze gebruikt bij werkzaamheden voor de Oosterscheldekering en bij de toelating van schepen in de Westerschelde. Een eerste versie van dit model is geëvalueerd om inzicht te krijgen in de voorspelkracht van ARMAX voor verschillende situaties. Daartoe zijn voor een periode van 10 maanden verschillende voorspellingen met metingen vergeleken. Het resultaat bestaat uit statistisch vergelijkingsmateriaal, aangevuld met casestudy's van geselecteerde stormperiodes.vloeistofmechanicaHydraulic EngineeringCivil Engineering and Geoscience
Instrumentos conceptuais e metodológicos na análise de riscos e nos processos de prevenção: a abordagem de Véronique De Keyser
No full textWe present the conceptual and methodological approach proposed by Véronique De Keyser to managing prevention and analysing professional risks. In this perspective conceptions and practices of prevention should always emerge and be structured by the risk analysis accomplished in context and with the participation of the concerned actors. We have structured the presentation of this approach in three parts. We begin by analysing the evolution of paradigms that support the understanding of risk evaluation and prevention management. Next we operationalise the concepts and the theories that characterise the contextual approach envisaged by the author to research/intervention in this domain. We conclude with the exposition of the most widespread methods in risk evaluation study, emphasising their use as instruments in order to promote transformations in views on conceptions and practices of prevention
Compact ornamentals by means of Rhizobium rhizogenes transformation and regeneration of Ri lines
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Instrumentos conceptuais e metodológicos na análise de riscos e nos processos de prevenção : a abordagem de Véronique De Keyser
No full textApresenta-se a abordagem conceptual e metodológica proposta por Véronique De Keyser para gerir a prevenção e analisar riscos profissionais. É uma perspectiva que sustenta que as concepções e as práticas da prevenção devem decorrer e estruturar-se sempre a partir do estudo dos riscos em contexto, com a participação dos diversos actores envolvidos. Estruturamos a apresentação desta abordagem [] em três grandes momentos. Iniciamos com a análise da evolução dos paradigmas utilizados na compreensão das ideias sobre a avaliação e prevenção de riscos. De seguida operacionalizamos os conceitos e as teorias que permitem caracterizar uma abordagem de tipo contextual na investigação/intervenção preconizada pela autora para este domínio. Concluímos com a apresentação dos métodos mais difundidos no estudo e na avaliação dos riscos, salientando a sua utilização como instrumentos ao serviço da transformação das formas de conceber a prevenção e as práticas que lhes estão associadas.Se presenta el planteamiento conceptual y metodológica propuesta por Véronique De Keyser para gestionar la prevención y analizar riesgos profesionales. Es una perspectiva que sustenta que las concepciones y las prácticas de la prevención deben transcurrir y estructurarse partiendo siempre del estudio de los riesgos en contexto, con la participación de los diversos actores involucrados. Estos son solicitados a desempeñar papeles activos en el análisis de las actividades de trabajo efectivamente realizado y en la consecuente construcción de alternativas con la finalidad de concebir y de concretar transformaciones sostenibles y duraderas teniendo en cuenta la fiabilidad de los sistemas productivos, la garantía de la seguridad y la promoción de la salud y del bienestar de las poblaciones trabajadoras. Estructuramos la presentación de este planteamiento [1] en tres grandes momentos. Iniciamos con el análisis de la evolución de los paradigmas utilizados en la comprensión de las ideas sobre la evaluación y prevención de riesgos. A continuación pasamos a la operatividad de los conceptos y las teorías que permiten caracterizar un planteamiento de tipo contextual en la investigación/intervención preconizada por la autora para este dominio. Concluimos con la presentación de los métodos más difundidos en el estudio y en la evaluación de los riesgos, destacando su uso como instrumentos al servicio de la transformación de las formas de concebir la prevención y las prácticas que les están asociadas.L’approche proposée par Véronique De Keyser pour une gestion de la prévention et une analyse des risques professionnels est au centre de cet article. Il s’agit d’une perspective selon laquelle les conceptions et les pratiques de prévention doivent toujours émerger et se structurer à partir de l’étude des risques dans le contexte où ils surviennent, et associer la participation des divers acteurs concernés. La présentation de cette approche est structurée en trois moments. Le premier ouvre l’article avec une analyse de l’évolution des paradigmes qui ont soutenu la compréhension des idées dans le domaine de l’évaluation et de la prévention des risques. On procède ensuite à une opérationnalisation des concepts et des théories qui caractérisent l’approche contextuelle prônée par l’auteure pour la recherche/intervention. On conclut enfin avec un exposé des méthodes les plus diffusées dans l’étude et l’évaluation des risques, en mettant en évidence leur utilisation comme instruments au service d’une transformation des façons de concevoir la prévention et les pratiques qui lui sont associées.We present the conceptual and methodological approach proposed by Véronique De Keyser to managing prevention and analysing professional risks. In this perspective conceptions and practices of prevention should always emerge and be structured by the risk analysis accomplished in context and with the participation of the concerned actors. We have structured the presentation of this approach in three parts. We begin by analysing the evolution of paradigms that support the understanding of risk evaluation and prevention management. Next we operationalise the concepts and the theories that characterise the contextual approach envisaged by the author to research/intervention in this domain. We conclude with the exposition of the most widespread methods in risk evaluation study, emphasising their use as instruments in order to promote transformations in views on conceptions and practices of prevention
Beschouwingen rond de huizencollectie van de Vereniging Hendrick de Keyser
No full textThe private Hendrick de Keyser Association, founded in 1918, now owns approximately 350 premises on the basis of which further study of the Dutch dwelling is possible. Research was not the object of the Association; its main concern was to save the premises by acquisition, restoration and responsible management. In the first decade the Association acquired 62 premises, which were restored in an austere manner. In 1928 all the houses appeared full-page in a memorial book containing 14 different contributions: Oud-Hollandse bouwkunst en haar behoud. In 1939 the Association owned 85 premises; after an introduction they were described chronologically by F.A.J. Vermeulen in the subsequent jubilee book of which reprints appeared in 1943 and 1944.
After the Second World War the collection steadily increased to 170 in 1968, which induced monument conservers R. Meischke and H.J. Zantkuijl to write Het Nederlandse Woonhuis van 1300-1800. A typology of houses was made on the basis of the internal structure, paying particular attention to the woodwork of the houses, such as the timber frames, wooden beams and lower fronts. Side rooms, entresols, upstairs flats and rear annexes were described and for the first time types like the broad and the double house were discussed.
After 1969 the collection of houses doubled, which gave rise to a four-volume publication, started in 1993, on the occasion of the 75th anniversary of the Association, and completed in 2000. Each volume consists of a description of related landscapes and an approximately similar number of houses. Each volume by itself is autonomous and includes a general, often thematically coloured introduction. The structure of the building trade was chosen as a main theme in an attempt at surveying architecture and technology as a unity. Through building-historical and dendrochronological research it is now possible to date the woodwork accurately, something that used to be so elusive.
For the new publication the old team of the Amsterdam Bureau for the conservation of monuments was available again: Zantkuijl, Raue and Meischke, together with the young art historian Paul Rosenberg who described each house once again and added historical data. The author works out a number of conclusions in the article, such as the organisation of the building trade, the role of carpenters and bricklayers, the influence of commissioners, the guilds and the urban building practice, the trade in building materials and the role of qualified architects
Integration of phenotype, genotype and gene expression to unravel flower colour biosynthesis and complex plant quality traits in azalea (Rhododendron simsii hybrids)
No full textAzalea breeding is a slow process, from the moment of crossing until the first flower can be evaluated, it already takes 3 years. At that time, selection is primarily based on the flower quality. Only when the seedlings have been cloned, other plant quality traits can be evaluated thoroughly. As a result, plants with attractive flowering are kept too long in the breeding cycle. Information on the inheritance of cultivation related quality traits is lacking, but the inheritance of flower colour has been well studied. Therefore flower colour was selected as a model system for genetical genomics in azalea. In this approach, phenotypic and genetic information is combined with gene expression data of candidate genes on a genetic map to unravel the regulation of the desired traits. In case phenotypic data are co-located with mapped candidate genes, these genes are proven to be directly involved in the creation of the phenotypic variation of the trait. Nevertheless, it is very likely that not the genes themselves but transcription factors are the switches that regulate the phenotype of the trait. In that case, phenotype and genotype will be mapped at different positions, but phenotype is then expected to be mapped together with the true regulators, the transcription factors. eQTL mapping of gene expression profiles from candidate genes will integrate this information on the genetic map.
Ultimately, our goal was to implement this model on the more complex plant quality traits as leaf morphology and plant architecture. However, candidate genes for these traits are lacking in azalea so far. Therefore, we limited ourselves to study the segregation of these complex traits in diverse genetic backgrounds and to evaluate the advantages of multi-population QTL mapping. For this purpose, leaf morphology (both colour and shape) and plant architecture have been scored in four unrelated populations. QTL mapping being the purpose, image analysis was used whenever possible to generate continuous, highly informative data. Both classical parameters and symmetrical elliptic Fourier descriptors performed well in describing leaf morphology. Image analysis resulted in a massive amount of data that had to be combined in principal component analysis. Leaf colour was split up in RGB values but was not always informative to discriminate between populations. Plant architecture was the most complex trait under study. Division in well-defined sub-traits as e.g. shoot length, plant area and number of shoots allowed to draw some preliminary conclusions on the inheritance of these complex traits. However, QTL mapping was the ultimate purpose with these data.
Genetical genomics requires candidate genes to be mapped. In azalea this was only possible for the flower colour biosynthesis genes of the anthocyanin pathway. However, EST data in azalea could also be explored in order to develop non-characterised but functional markers in conserved genomic regions. Both intron-spanning EST-based markers and EST-SNPs were developed and the advantages of both marker types were discussed. HRM-based EST-SNP mapping is clearly the method of choice for future candidate gene mapping. The EST-based functional markers were, together with myb-based markers as candidate genes for transcriptional regulation of flower colour, scored in a single mapping population. AFLP and SSR markers were analysed in all four populations as a reference backbone. An integrated framework map on the four individual linkage maps was constructed. A combination of regression mapping (JoinMap) and multipoint-likelihood maximisation (Carthagène) enabled the alignment of the four maps on the basis of framework markers. This facilitated in turn the alignment of QTL regions detected in individual populations for the complex traits under study. The focus was on the detection of multi-population QTLs, since these QTLs were assumed to be more conserved in the overall azalea gene pool and therefore more apt for breeding purposes. No such QTLs for branching were detected, plant architecture resulted in one combined QTL. Several leaf morphology QTLs were found, many of them were related to the leaf width to length ratio which is the most discriminative factor for azalea leaves. Overall, populations ‘CxD’ and ‘GxH’ were more appropriate for leaf morphology studies, whereas population ‘ExF’ resulted in the highest number of QTLs related to plant architecture.
Flower colour was selected as a model system for genetical genomics. In the same way as for the other traits, image analysis was used to turn flower colour into a variable suitable for QTL mapping. Gene expression profiles of the anthocyanin biosynthesis pathways were also to be added onto the genetic map by means of eQTL mapping. This required the establishment of a reliable RT-qPCR protocol for transcriptional profiling. RT-qPCR is a highly sensitive method that required intensive optimisation. Unfortunately, the expression profiles could not discriminate between the flower colour groups. However, these data could be used to identify the genetic regulatory loci explaining the observed variation in flower colour by eQTL mapping. The minimal population size required to have sufficient power for eQTL mapping was set at 70 plants. The gene expression profiles were therefore determined on a subset of 70 siblings of the mapping population segregating for flower colour. eQTLs in combination with QTLs for the flower colour phenotype were positioned on the genetic linkage map. Since the map also contained functional markers for flower colour biosynthesis, the integration of phenotypic, genetic and transcriptional information allowed to elucidate partly the process of flower colour biosynthesis in azalea. Coordinated expression of the early pathway genes was confirmed by eQTL mapping of these genes in the region of a myb-fragment. RT-qPCR proved to be a good method for expression profiling in a genetical genomics approach and even has some advantages compared to conventionally applied micro-arrays. The co-localization of the FLS gene expression with a QTL for the co-pigmentation phenotype at the locus Q served as a proof of concept. No solid conclusions could be drawn yet concerning pink and white. However, the first is most likely a gene-dosage effect and the latter seems to be regulated at the transcriptional level
Mesh deformation using radial basis interpolation on periodic domains with small clearance gaps
No full textIn this thesis report, a new radial basis function (RBF) interpolation mesh deformation method is investigated that is applicable on periodic domains that contain small clearance gaps. In the field of fluid structure interaction, there is a strong interaction between a structure and the fluid in which this structure is immersed. When performing simulations of this interaction, the fluid mesh has to adapt to the changing domain which occurs due to the structure deforming. The adaption of the fluid mesh can be done with an RBF interpolation method. Although this is considered to be one of the most robust methods available, there are specific cases in which the method can still yield some poor quality deformed meshes. This is for example the case when small clearance gaps are present such as the region between a blade and the shroud in turbomachinery. Then it becomes beneficial to allow boundary nodes to slide to improve the mesh quality.In turbomachinery, periodic domains are also often encountered, for example in a gas turbine. Here, the same blade is constantly repeated, allowing to use one single blade in computations which will have a domain with periodic boundaries. In general, the larger the number of blades, the smaller the distance between the blade and the periodic mesh boundary will be. Hence, also here small clearance gaps are present. As the blade might undergo a large deformation, it is possible for the blade to even intersect the mesh boundary if this boundary is kept fixed, which would lead to a degenerate mesh.The aim of this thesis is to avoid this scenario by making adaptions to the RBF interpolation method that allow the periodic boundaries of the mesh to be displaced with the deforming blade. Evidently, this has to be done in a periodic manner, keeping both periodic boundaries equal. This will yield a higher mesh quality of the deformed mesh as it will reduce the skewness and avoid the occurrence of degenerate cells. Two different methods for periodic boundary displacement are investigated in this report. Both methods work for both translational and rotational periodic boundaries and several two-dimensional (2D) and three-dimensional (3D) meshes are used as test cases.The first method is the periodic distance method which is based on making the distance between the boundary nodes periodic. This method is very similar to the regular RBF method and only requires a regular Euclidean distance function to be replaced by a periodic distance function. This means that the computational cost is also similar to an interpolation matrix of size Nm x Nm. This method shows good results for both 2D and 3D meshes and both types of periodic boundaries. Apart from giving the periodic boundaries an identical displacement, it also allows for a smooth transition from one mesh to another.The second method is based on equal displacement. Hence, the RBF interpolation matrix is adapted to include conditions imposing equal displacement of the periodic boundary nodes. These extra conditions yield a larger interpolation matrix of size Nm+Np x Nm+Np. This means the computational cost for this method is higher than for the periodic distance or the regular RBF method. This method also shows good results in terms of deformed mesh quality but does not feature the same smoothness over the interface between two meshes and creates small kinks at the interface.Even though RBF interpolation can be relatively low in computational cost compared to other mesh deformation methods that require mesh connectivity information, it still becomes computationally expensive for large 3D problems with a high number of nodes. Therefore, a greedy algorithm is also used for larger problems which allows for a reduced amount of nodes selected to perform the interpolation.In conclusion, the periodic displacement method used with RBF interpolation shows great potential for different types of problem sizes and periodic boundaries and can potentially make the simulation process of periodic problems much more efficient.Aerospace Engineerin
Spanningsverloop in dunne amorfe Mo/Si-multilagen tijdens een gloeibehandeling onder de glastemperatuur
No full textFysische en Chemische MetaalkundeTechnische MateriaalwetenschappenMechanical, Maritime and Materials Engineerin
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