2 resultados para Finite elements method

em Helda - Digital Repository of University of Helsinki


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"Infinitive and its infinity" advocates an approach to infinitives that differs from most previous descriptions in several ways. Infinitives are generally considered to be an illustrative example of an inherently subordinated verb category. This is due to the fact that they are morphologically reduced and are allegedly not able to function as the only predicate of an independent clause. While former descriptions have thus treated infinitives as a linguistic category heavily dependent on the finite verb, my claim is that Finnish A-infinitives (e.g. juosta to run , olla to be ) can be used as independent grammatical units: they need not be either dependent or subordinated, but can have an equal status with finite constructions. In other words, they can be conceptually and interactionally non-dependent. Theoretically, the main objective of the thesis is to discover the nature of non-finite conceptualization and the ways in which it is utilized in everyday interactions. This is accomplished by contrasting finite and non-finite conceptualization with respect to the morphosyntactic marking of person, tense and modality. I argue that the morphologically reduced nature of infinitives can be used as an interactional resource. Independent A-infinitive constructions designate verbal processes that profile no participants, lack any connection with time, and present states of affairs as intensional, structural spaces. Consequently, they provide the interactants with a conceptual alternative in contrast to finite predications that are in Finnish always grammatically anchored to time, modality and person. The deictically unanchored character of A-infinitive constructions makes them highly affective and reflexive in nature. I discuss my findings primarily in the light of Cognitive Grammar. I have drawn insight from various other fields, too: among the theories that are touched upon are interactional linguistics, functional-typological linguistics, and studies on the poetic and metapragmatic use of language. The study is based on empirical data interpreted in qualitative terms. Analyses are based on 980 examples coming mainly from written language. Some 20 examples of spoken data are analyzed as well. In sum, the thesis presents a critical statement towards the finite-verb centred outlook on language and shows that analyzing non-finite elements as such reveals new aspects of grammar and interaction. This is to acknowledge the fact that infinitives, albeit prototypically participating in the coding of dependent events, can also be used outside of the context of the finite verb. Such a view poses several new research questions, as a linguistic category generally seen to code dependent, less prominent states of affairs , now is viewed on as possessing a full cognitive and pragmatic potential.

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Nucleation is the first step in the formation of a new phase inside a mother phase. Two main forms of nucleation can be distinguished. In homogeneous nucleation, the new phase is formed in a uniform substance. In heterogeneous nucleation, on the other hand, the new phase emerges on a pre-existing surface (nucleation site). Nucleation is the source of about 30% of all atmospheric aerosol which in turn has noticeable health effects and a significant impact on climate. Nucleation can be observed in the atmosphere, studied experimentally in the laboratory and is the subject of ongoing theoretical research. This thesis attempts to be a link between experiment and theory. By comparing simulation results to experimental data, the aim is to (i) better understand the experiments and (ii) determine where the theory needs improvement. Computational fluid dynamics (CFD) tools were used to simulate homogeneous onecomponent nucleation of n-alcohols in argon and helium as carrier gases, homogeneous nucleation in the water-sulfuric acid-system, and heterogeneous nucleation of water vapor on silver particles. In the nucleation of n-alcohols, vapor depletion, carrier gas effect and carrier gas pressure effect were evaluated, with a special focus on the pressure effect whose dependence on vapor and carrier gas properties could be specified. The investigation of nucleation in the water-sulfuric acid-system included a thorough analysis of the experimental setup, determining flow conditions, vapor losses, and nucleation zone. Experimental nucleation rates were compared to various theoretical approaches. We found that none of the considered theoretical descriptions of nucleation captured the role of water in the process at all relative humidities. Heterogeneous nucleation was studied in the activation of silver particles in a TSI 3785 particle counter which uses water as its working fluid. The role of the contact angle was investigated and the influence of incoming particle concentrations and homogeneous nucleation on counting efficiency determined.