[diss] Teknillinen korkeakoulu / TKK

Permanent URI for this collectionhttps://aaltodoc.aalto.fi/handle/123456789/113909

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Energy measurement in collider experiments and the search for scalar quarks in Z⁰ decays at LEP 1
(1991) Keränen, Reino
Helsinki University of Technology | Doctoral dissertation (monograph)
Modelling of transport processes in porous media for energy applications
(1996) Kangas, Markku
Helsinki University of Technology | Doctoral dissertation (article-based)
Flows in porous media are encountered in many branches of technology. In these phenomena, a fluid of some sort is flowing through porous matrix of a solid medium. Examples of the fluid are water, air, gas and oil. The solid matrix can be soil, fissured rock, ceramics, filter paper, etc. The flow is in many cases accompanied by transfer of heat or solute within the fluid or between the fluid and the surrounding solid matrix. Chemical reactions or microbiological processes may also be taking place in the system. In this thesis, a 3-dimensional computer simulation model THETA for the coupled transport of fluid, heat, and solute in porous media has been developed and applied to various problems in the field of energy research. Although also applicable to porous medium applications in general, the version of the model described and used in this work is intended for studying the transport processes in aquifers, which are geological formations containing groundwater. The model highlights include versatile input and output routines, as well as modularity which, for example, enables an easy adaptation of the model for use as a subroutine in large energy system simulations. Special attention in the model development has been attached to high flow conditions, which may be present in Nordic esker aquifers located close to the ground surface. The simulation model has been written with FORTRAN 77 programming language, enabling a seamless operation both in PC and main frame environments. For PC simulation, a special graphic user interface has been developed. The model has been used with success in a wide variety of applications, ranging from basic thermal analyses to thermal energy storage system evaluations and nuclear waste disposal simulations. The studies have shown that thermal energy storage is feasible also in Nordic high flow aquifers, although at the cost of lower recovery temperature level, usually necessitating the use of heat pumps. In the nuclear waste studies, it was found that the heat generation of the spent fuel has a marked effect on the groundwater flow near the repository for thousands of years, increasing the flow rate at most to five-fold compared to the natural situation. In the applications, the model has proven to be a versatile tool and easily applicable in various situations. As a future development, the inclusion of unsaturated zone simulation as well as improvements in solute transport routines are being considered.
Effect of nitrogen content on precipitation behaviour and properties of P/M high nitrogen austenitic stainless steels
(2000) Romu, Jyrki
Helsinki University of Technology | Doctoral dissertation (monograph)
Wear properties of high nitrogen austenitic stainless steels
(1998) Tervo, Jyrki
Helsinki University of Technology | Doctoral dissertation (monograph)
Innovation generating model - simultaneous development of work organization and knowledge infrastructure : experimenting in the field of organizational development
(2008) Ramstad, Elise
Helsinki University of Technology | Doctoral dissertation (monograph)
International negotiations : a multi-case study on negotiation differences between Finnish and Chilean businessmen
(2003) Kriman, Alex
Helsinki University of Technology | Doctoral dissertation (monograph)
Henkilöstöinformaation tulkinta ja käyttö julkisissa organisaatioissa
(2002) Borg, Kristiina
Helsinki University of Technology | Doctoral dissertation (monograph)
Drop size distributions in liquid sprays
(1994) Paloposki, Tuomas
Helsinki University of Technology | Doctoral dissertation (monograph)

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