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    Numerical modeling of spectral radiative properties of fuel vapors in fires
    (Aalto-yliopisto, 2022) Sadeghi, Hosein; Bordbar, Hadi; Rakennustekniikan laitos; Department of Civil Engineering; Insinööritieteiden korkeakoulu; School of Engineering; Hostikka, Simo
    In combustion and fire, fuel vapors emerge in the gasification phase. Experimental studies have shown that the amount of these vapors close to the fuel surface is considerably high. It, therefore, alters radiative heat flux reaching the fuel and consequently, the fuel mass loss rate and the combustion mechanism. Due to the spectral nature of thermal radiation and the strong dependency of spectral radiative properties of fuel gases on temperature, there is a need for suitable models to account for the effect of fuel gases in radiative heat transfer. In this work, non-gray thermal radiation in fuel vapors is studied and novel weighted-sum-of-gray gases models (WSGG) are developed for Heptane, Methane, Methanol, MMA, Propane, Propylene, Toluene, Carbon Monoxide and soot. To develop the WSGG models, experimentally measured high-resolution spectral absorption data are used for Heptane, Methane, Methanol, MMA, Propane, Propylene and Toluene and line-by-line spectral data are employed for Methane and Carbon Monoxide. For soot, the complex index of refraction is calculated by the correlations of Chang and Charalampopoulos. The soot spectral absorption coefficient is then calculated assuming Rayleigh regime for soot particles. The obtained WSGG models are validated in five one-dimensional cases and in a three-dimensional case. The superposition method is employed to mix WSGG models of different species. In all the cases, the results obtained from the WSGG modeling are compared with line-by-line integration and they show a good accuracy. The method increased the number of required solutions of radiative transfer equation (RTE) up to 2500 in some cases but using premixed WSGG models for H2O-CO2 mixture, the number of the required RTE solutions decreased to 25 gases. Compared to the gray solution, the CPU time of the WSGG modeling with 25 gray gases was 12.9 times higher, however, the average error of heat source decreased from 18.3% for gray solution to 3.93% for WSGG modeling compared to LBL integration.
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    Georeferencing and stereo model formation of aerial oblique photographs
    (2015) Nurminen, Kimmo; Honkavaara, Eija; Hyyppä, Juha; Insinööritieteiden korkeakoulu; Insinööritieteiden korkeakoulu; School of Engineering; Haggrén, Henrik
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    Corporate social responsibility practices in real estate business - Is co-operation the key to enhancing sustainability ?
    (2015) Andelin, Mia; Rasila, Heidi; Junnila, Seppo; Insinööritieteiden korkeakoulu; Insinööritieteiden korkeakoulu; School of Engineering; Junnila, Seppo
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    The content of constructability; Preliminaries for co-operational development of constructability in Finland
    (2015) Tauriainen, Matti Kalervo; Saari, Arto; Insinööritieteiden korkeakoulu; Insinööritieteiden korkeakoulu; School of Engineering; Puttonen, Jari
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    Experimental and theoretical studies of energy efficient convective heat transfer, mass transfer and heat storage
    (2013) Meriläinen, Arttu; Seppälä, Ari; Energiatekniikan laitos; Insinööritieteiden korkeakoulu; School of Engineering; Lampinen, Markku
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    Täydennysrakentamisen haasteet ja talous-, energia- ja ympäristövaikutukset
    (2013) Seppälä, Tiina; Saari, Arto; Energiatekniikan laitos; Insinööritieteiden korkeakoulu; School of Engineering; Siren, Kai
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    Foundries as suppliers
    (2012) Saarelainen, Tanja; Orkas, Juhani; Koneenrakennustekniikan laitos; Insinööritieteiden korkeakoulu; School of Engineering; Coatanéa, Eric
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    RANS analyses of cavitating propeller flows
    (2012) Sipilä, Tuomas; Siikonen, Timo; Rautaheimo, Patrik; Sovelletun mekaniikan laitos; Insinööritieteiden korkeakoulu; School of Engineering; Matusiak, Jerzy
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    Key issues of mass valuation in countries under transition
    (2012) Tomson, Alvar; Plimmer, Frances; Falkenbach, Heidi; Maankäyttötieteiden laitos; Insinööritieteiden korkeakoulu; School of Engineering; Viitanen, Kauko
    During the last two decades there have been phenomenal changes in political structures in post-socialist Central and Eastern European countries. Those changes have been based on different principles, but have all resulted in major land reforms. As real estate in terms of a free market was something unknown for those countries, a lot of problems have followed the reform process. This research is focused on the interpretation of the key issues of mass valuation in circumstances of undeveloped property markets in countries in transition. The analysis was grounded on the case study of mass valuation systems for real estate taxation in the Baltic countries and on the case study of mass valuation systems for land restitution in Albania. Although there were differences in the time frames, in the aim of introducing market valuations, etc. the same topics were covered. Thus, topics like the differences between mass appraisals and single-property valuations, market and non-market value, the reappraisal cycle, valuation date, etc. are discussed from a theoretical point of view and practical aspects are presented as part of the case studies. The discussion section contains consideration within a wider context and inspects the relationship of this investigation with earlier research. Combining the conclusions made based on development of mass valuation systems in Baltic countries (analysed period 1993-2003) and Albania (analysed period 2005-2006), two conclusions can be drawn:. The first, the analysis shows that deviations in interpretation of the key issues of mass valuation are rather typical for all countries handled in the current research. There seems to be no significant distinction based on the level of development of the property system or some other relevant characteristics. The second conclusion derived from the observations made in the context of development of mass valuation systems in circumstances of undeveloped property markets in countries in transition is that external influences have turned valuation into part of the political decision-making process. Although it was more clearly identified within the Albanian context, this was to a certain level typical in the Baltic countries as well. The practical implications of the findings occur at two levels:. First, at the general level, the research has provided an understanding about the development of mass valuation systems in countries in transition where undeveloped market circumstances are rather typical. A better understanding of these cases can provide lessons as to how other countries might develop (or might not develop) their own systems. At the country level, the findings can be used for stimulating the mass valuation systems which in the wider context are a part of the fundamentals of the taxation system (reform process) and national economy.
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    Hardness prediction of a laser hybrid welded joint using FE simulation
    (2011) Tamminen, Tero; Remes, Heikki; Sovelletun mekaniikan laitos; Insinööritieteiden korkeakoulu; School of Engineering; Varsta, Petri
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    Teollisen tuotannon sivuainevirtojen hyödyntäminen - ajurit, esteet ja yrityksen liiketoimintamahdollisuudet
    (2011) Pajunen, Nani; Heiskanen, Kari; Maanmittaustieteiden laitos; Insinööritieteiden korkeakoulu; School of Engineering; Werdi, Erja
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    Vastuun kantajat - Asunto-osakeyhtiön hallituksen jäsenen vastuu ja sen aktualisoituminen
    (2011) Malk, Markus; Maanmittaustieteiden laitos; Insinööritieteiden korkeakoulu; School of Engineering; Werdi, Erja
    The purpose of this study is to analyse the content of the expression 'the liability of a board member' of an apartment house company in the context of Apartment House Company Law (1599/2009). The research methodology used in this study is a multidisciplinary approach. It combines perspectives of dogmatics of law, philosophy of language and discourse research. A board member can become personally liable for damages when he or she takes care of the tasks of the board, i.e. deals with the company's management, arranges maintenance and other operations of the company, and is responsible for accounting and arranging proper financial management. Membership of the board should be understood from its actual nature; a person may take care of the tasks of the board regardless of his or her formal position in the company. A board member owes a duty of care and a duty of loyalty to the company. He or she owes under all circumstances the duty to exercise care when he or she maintains living conditions of inhabitants living in the building owned by the company. Care in this context means to avoid damages beforehand by finding out issues the board has at hand and considering rationally problems connected to such issues. Nevertheless, the criteria of care do not exclude damages. They can occur in real life even though operations are run with care. According to the idea of complete liability presented in this study, membership of the board is not to actions one does or does not in the official meetings. According to the idea of complete liability a board member has a permanent position which is valid as long as he or she is a factual member of the board. From the point of view of the idea of complete liability presented in this study, in the context of an apartment house company, the board member has a common duty to act. Even if he or she would not participate in the board meetings in an active way he or she is liable for the actions the board does for his or her own part. An evaluation of a board member's complete liability includes that one must take into account whether a board has shared its tasks or transferred them or outsourced them. On the other hand, one must take into account contextual factors like a size of the company and a member's personal features like ignorance and disqualification.
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    One solution fits all? Differences in work environment preferences of office occupiers
    (2011) Rothe, Peggie; Lindholm, Anna-Liisa; Maanmittaustieteiden laitos; Insinööritieteiden korkeakoulu; School of Engineering; Junnila, Seppo
    Satisfaction, productivity, and well-being of employees are crucial for organizations that want to achieve a competitive advantage in today's knowledge intense business environment. There is a growing body of evidence linking the work environment with employee satisfaction and performance. In order to create work environments that result in satisfied and productive users, user satisfaction with their current workplaces is a key research area. However, it is important to also widen the research agenda and identify more precisely what the actual users want, instead of focusing solely on how they are experiencing the existing situation and adapting to the environment. The purpose of this study is to contribute to the body of knowledge of office users' work environment preferences. Offices today host users with different demographic backgrounds and ways of working, in order to provide work environments that meet the preferences of all users, it is important to understand how users' work environment preferences differ. This study aims to investigate whether there are differences in the work environment preferences of different users. The study has a quantitative approach and is conducted with an internet survey as the main data collection method. The results show that office users' work environment preferences vary both based on age and gender, as well as based on how they work. However, different background variables affect the preferences concerning different work environment features. For example, age had an impact on the users' preferences concerning the service offering in the work environment, while preferences concerning the virtual environment were more depended on how the user works, rather than age. The study also presents a way to profile office users based on their preferences, across demographics and ways of working. The result was three groups with internally homogenous preferences, comprising respondents with different backgrounds and different ways of working. The groups were 'service and green value driven users', 'individual driven users', and 'collaboration driven users that wish to influence their work environment'. In practice, the results of this study mean that designing one work environment solution to fit all will end up a compromise for all. As it is impossible to satisfy all different kinds of users - no matter age, gender or ways of working - with only one solution, the future work environments have to enable flexible use, and allow the users to make more decision themselves. Also, in order to capture all various work environment preferences, user involvement has to be a key driver in work environment development and management in the future.
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    Structural lifetime, reliability and risk analysis approaches for power plant components and systems
    (2011) Cronvall, Otso; Simola, Kaisa; Paavola, Juha; Rakennustekniikan laitos; Insinööritieteiden korkeakoulu; School of Engineering; Paavola, Juha
    Lifetime, reliability and risk analysis methods and applications for structural systems and components of power plants are discussed in this thesis. These analyses involve many fields of science, such as structural mechanics, fracture mechanics, probability mathematics, material science and fluid mechanics. An overview of power plant environments and a description of the various degradation mechanisms damaging the power plant systems and components are presented first. This is followed with a description of deterministic structural analysis methods, covering e.g. structural mechanics and fracture mechanics based analysis methods as well as the disadvantages of the deterministic analysis approach. Often, physical probabilistic methods are based on deterministic analysis methods with the modification that one or more of the model parameters are considered as probabilistically distributed. Several probabilistic analysis procedures are presented, e.g. Monte Carlo Simulation (MCS) and importance sampling. Description of probabilistic analysis methods covers both physical and statistical approaches. When the system/component failure probabilities are combined with knowledge of failure consequences, it is possible to assess system/component risks. Several risk analysis methods are presented as well as some limitations and shortcomings concerning to them. Modelling methods for various degradation (or ageing) mechanisms are presented. These methods are needed in the lifetime analyses of structural systems and components of power plants. In general, the lifetime analyses in question necessitate a thorough knowledge of structural properties, loads, the relevant degradation mechanisms and prevailing environmental conditions. The nature of degradation models of structural systems/components can be deterministic, probabilistic or a combination of these two types. Degradation models of all these kinds are presented here. Some important risk analysis applications are described. These include probabilistic risk/safety assessment (PRA/PSA) and risk informed in-service inspections (RI-ISI). In practise, lifetime and risk analyses are usually performed with a suitable analysis tool, i.e. with analysis software. A selection of probabilistic system/component degradation and risk analysis software tools is presented in the latter part of this thesis. Computational application of probabilistic failure and lifetime analyses to a representative set of NPP piping components with probabilistic codes VTTBESIT and PIFRAP are presented after that. The thesis ends with a summary and suggestions for future research.
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    Jäähdytetyn myymäläkalusteen rakenteelliset ja toiminnalliset parametrit
    (2011) Sipilä, Tomi T.; Energiatekniikan laitos; Insinööritieteiden korkeakoulu; School of Engineering; Sirén, Kai
    In a modern day supermarket approximately 45 - 50% of the total electricity consumption is consumed by the refrigerating of perishable food products. Open refrigerated display cases that have been used to display the products have a significant contribution to that. The cabinets have been favoured due their boost in sales but the main disadvantage is their high energy consumption thus 70 - 75% of the energy load is transferred through an opening. The most trivial method to reduce the consumption is to equip the cabinets with doors and lids. Nevertheless that has not gained an acceptance in major supermarket chains yet and thus other means must be applied. According to the previous air curtain and display cases studies the heat flow from ambient to the air curtain can be expressed as a function of fourteen constructional and operational parameters of the display case. This research project used the technique of experimental studies to analyse the influences of twelve of these parameters on an air curtain equipped multi-deck display case. During the course of the study a custom designed experimental facility was constructed and located into the climate chamber, where ambient conditions were controlled and held constant during the measurements. The results of the measurements indicated that the parameters air curtain initial velocity distribution and its initial turbulence, air curtain Reynolds number, air flow rate through a perforated back panel and location angle of an air curtain intake grill have the most significant influence on the performance. When a construction of the display case is considered the last three parameters are the most important ones. Their influence on the target variables, cooling load and maintained product temperatures had a divergent pattern and thus they are practically defining the basic level of the cabinet performance. The rest of the parameters can be applied as a fine-tuning of the performance only.
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    Advanced heat transfer modelling with application to internal combustion engine CFD simulations
    (2011) Nuutinen, Mika; Kaario, Ossi; Energiatekniikan laitos; Insinööritieteiden korkeakoulu; School of Engineering; Larmi, Martti
    At present, majority of the detailed modelling related to engine performance, gas flow, combustion, and emissions is performed with Computational Fluid Dynamics (CFD) simulations. The Reynolds Averaged Navier Stokes (RANS) turbulence models are most widely utilized due to turbulent flow conditions, complex geometries, and complicated sub models. Although Large Eddy Simulation (LES) and Direct Numerical Simulation (DNS) are more accurate than RANS models, their application in engineering simulations is often limited due to high computational costs. Available heat transfer modelling options utilized with RANS turbulence models comply poorly with engine flows. They are either completely inadequate for the particular flow conditions, or their validity requirements may multiply the problem size and computational costs. The work in this thesis concentrates on development of an accurate, engine flow compliant heat transfer I near wall modelling formalism within RANS framework. The model development yields reformulation of the whole near wall treatment, intrinsically improving the entire near wall accuracy of utilized turbulence models. Furthermore, the developed models are universal and by no means restricted to engine simulations alone. This thesis comprises a survey of the research field and three attached original publications. The first publication presents numerical wall function formalism designed to include effects of strong temperature gradient induced density variation on wall heat and momentum transfer models. The objective was to study conjugate heat transfer from charge gas to piston material in order to get estimates for piston surface temperatures and heat loss. The results indicated that the near wall density variation has a significant effect on peak surface temperature and overall heat transfer predictions. The following research indicated that the temperature gradient induced variations of charge gas viscosity, conductivity, and heat capacity affect the heat transfer prediction as well. Furthermore, this new formalism facilitates rigorous computation of the turbulence model source terms in the near wall region. These source terms affect the near wall turbulence level, strongly coupled with the heat and momentum transfer models. Following these ideas in two subsequent publications, advanced models were developed and implemented. A commercial CFD software, Star-CD, extensively utilized in internal combustion engine CFD simulations, was used as a primary platform for model development and simulations. In addition, an in-house CFD solver was programmed for model testing and validation. This thesis contributes to the research field by providing a comprehensive theoretical approach to heat transfer related near wall modelling within RANS framework and complete theory based models directly applicable to engineering CFD simulations.
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    Vapaasti seisovat poikkileikkaukseltaan kolmionmuotoiset ristikkotornit
    (2011) Lehtinen, Alpo; Rakennustekniikan laitos; Insinööritieteiden korkeakoulu; School of Engineering; Mäkeläinen, Pentti
    This thesis deals with free standing lattice towers with triangular cross-section shape and height under 100 metres. The main object of this thesis is dimensioning the individual parts of the towers and find out support reactions of the tower. All other measures done serve the main object. These kinds of structures are special structures whose ratio height to breadth is typically high. Based on the height of the structure the most important load is wind. This work has been done in time period where the process to adopt Euro code standards continued. The material used in this work based on both ENV-standards and EN-standards. Inside the work period there were the corrigendum for tower and mast standard and changes in Finnish national annexes for tower and mast standard and wind standard (EN 1991-1-4). During this work came up an observation that this kind of the structures are more difficult to calculate than lower structures for example because of the dynamic effects from wind load. Instructions to calculate tower structures are given in standard EN 1993-3-1 / Part 3-1. The background standard for this work is SFS-EN 1993-3-1 + AC with Finnish national annex so called NA (Change 1, 5.11.2010). Above-mentioned standard includes the corrigendum AC:2009. The National annex gives additional instructions to the points where the National choice is possible. For example the Finnish NA determines that the wind loads are taken according to EN 1993-3-1 / Annex B instead of the standard EN 1991-1-4 (wind standard). The scope of this thesis includes strength, stability and fatigue considerations of individual parts of towers. In addition the work discusses shortly manufacturing based on EN 1090-2. Selection of execution class is important. Selected execution class will determine many actions for manufacturing process. Fire design is outside the scope of this work although it is also important (most cases the lower part of the towers is important to protect against the fire risk). Calculation examples to determine wind effects for the structures both ice free and icy are presented in annexes 2 and 3. Traditionally wind is deemed as load which does not cause fatigue. According to tower and mast norm there is no need to consider fatigue effects in direction of the wind. Despite of above mentioned the way to determine equivalent constant amplitude stress range is presented based on the figure B.3 in wind standard. A load effect from vortex shedding is not included in this thesis. In principle it is possible to develop transverse load effect (vortex shedding) from supported pipe which has about same height than tower (the pipe is supported to the tower). In this case the tower and the pipe vibrate connected each other's (same frequency). Basic problem is to get the parameters needed to calculate transverse load effect. In same paragraph with designing of new tower structure there is few words about selection of material for fracture toughness and lamellar tearing.
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    Managing integration of company mergers and acquisitions in particular in cross cultural construction project business
    (2011) Lönnrot, Tuija; Kiiras, Juhani; Rakennustekniikan laitos; Insinööritieteiden korkeakoulu; School of Engineering; Junnonen, Juha-Matti
    The likelihood for success of mergers and acquisitions is less than commonly have been estimated. Almost 80% of mergers and acquisitions do not achieve their financial objectives and about 50% simply fail. The reason for this besides the failure of the deal can be found from the integration process and from cultural differences. The observation of the management of integration of company mergers and acquisitions in particular in cross cultural construction project business is needed. Also the correlation of success and failure factors of mergers and acquisitions, integration and cultural issues to construction project business would be interesting and challenging to find out. As the research problem it is to chart from the literature the processes of mergers and acquisitions as well as the success and failure factors covering also integration phase and cultural integration in mergers and acquisitions. Also the problem is to find out, how common theory about mergers and acquisitions, integration and cross cultural issues can be applied to construction project business. The aim of this applicative literature study is divided into two: to analyse the aspects related to integration phase of international mergers and acquisitions as well as to chart success and failure factors of mergers and acquisitions. The context of the study is the construction project business. The definition of relevant literature covers the most important authors and their publications what comes to the topic. It is not possible to cover all publications written, but the aim is to have a good understanding, who are the authors specialized in this field and if there is enough literature written of this narrow field of construction project business in the environment of cross cultural mergers and acquisitions facing the integration phase. As a result of this study (licentiate thesis) gives a good overall picture of which factor has to be taken into consideration, when integrating mergers and acquisitions, and which issues affect on success and failure of mergers and acquisitions in a cross cultural construction project business. Also processes of mergers and acquisitions, integration, and also of cultural integration have been described. This research (licentiate thesis) will also give a good basis for further studies (for doctoral thesis).
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    Optical measurements of diesel fuel spray on medium speed engine
    (2011) Sarjovaara, Teemu; Energiatekniikan laitos; Insinööritieteiden korkeakoulu; School of Engineering; Larmi, Martti
    This Licentiate's Thesis examines experimental approach to fuel spray of medium speed diesel engine. Fuel spray and its local conditions determine the emission generation on compression ignition engine, where the combustion is traditionally mixing controlled. Optical measurement methods offer excellent way to study highly turbulent fuel sprays both in optical engines and in chambers. The gathered results can be utilized to increase the knowledge of basic fuel spray physics, develop combustion process and to offer reference data for numerical simulations. There are a lot of reported optical measurements of diesel fuel spray and combustion, but they have concentrated on small high speed engines. There have been only few studies focusing on large bore engines. Large bore engines are more challenging to modify for optical measurements, since their dimensions and high cylinder pressures, and also the emission legislation have not been as strict as with smaller engines. The thesis presents measurements of medium speed engine's fuels spray. Two optical measurement methods are presented -particle image velocimetry (PIV) and backlight imaging. The measurements have been carried out in cold chambers and in optical engine. The results gathered for the chamber measurements have excellent quality while results from engine measurement did have some quality problem. But both measurement results offered valuable information from in-cylinder phenomena of large bore medium speed diesel engine.
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    Biologinen typen- ja fosforinpoisto jätevesistä - Nitrifikaation tehostaminen vapaasti kelluvilla kantoainekappaleilla
    (2010) Rantanen, Pirjo; Yhdyskunta- ja ympäristötekniikan laitos; Insinööritieteiden korkeakoulu; School of Engineering; Vahala, Riku
    The enhancing of nitrification with free-swimming carriers was studied on this thesis. In the Literature part the prevailing theory of nitrification was reviewed, as well as biofilm processes and the research concerning biofilms and alternative biological processes to nitrification. In the Experimental part a process with biological nitrogen and phosphorus removal with a nitrifying biofilm was studied. The experiments were conducted in semi-technical scale. The following conclusions were made in the study: The nitrification rate of 1,3 gNO3-N m-2 d-1 is critical in dimensioning, and a higher rate probably cannot be used as the basis of dimensioning, because the maximal rate (2,0 gNO3-N m-2 d-1) cannot be utilized in practice. In a low temperature, e.g. 10 °C, the rate to be chosen would be 0,75 gNO3-N m-2 d-1 or lower. A process similar to the carrier line could be dimensioned to a smaller volume than the process based on bare activated sludge, if the basis of the dimensioning is the lowest temperature of the year following the melting of snow, as is common in Nordic countries. In these limiting conditions the higher nitrification potential of the carrier line became evident more clearly than in normal conditions. When the nitrification rates were compared to those reached by a hybrid process with a fixed carrier combined to activated sludge (Germain et al., 2007), 0,16-0,34 gNH4-N m-2 d-1 (8-9,2 °C) and 0,18-0,80 gNH4-N m-2 d-1 (14-19,5 °C), it can be noticed that the rates reached in this study were higher in respective temperatures. The concentration of dissolved oxygen could be used as a control parameter in a hybrid process. The nitrification in the carrier line was limited by the concentration dissolved oxygen half of the time and the concentration of ammonium half of the time. The optimal running parameters of the carrier line were depending on conditions: return sludge flow 100-150 %, nitrate recycle flow 115-150 %, anoxic recycle flow 110 % and the concentration of dissolved oxygen 3,0-7,5 mg l-1 according to a simplex optimization. All the online analysers needed monitoring with the laboratory analyses process samples. The following further studies arose from this thesis: What would be the minimal size of the carrier line year round at least as well as the activated sludge line? Fitting of a deterministic or other model to a process similar to the carrier line and verifying it. The A study of the temperature dependence of nitrification in a process similar to the carrier line. Studying the interactions between the biofilm and activated sludge considering the optimal: dimensioning of the process, the filling rate of the carrier and the required effective area as well as the( running conditions. The calculation of the sludge age in a process is similar to the carrier line sot, that it would be meaningful considering nitrification as well as the limiting sludge age, and which parameter it depends on.