[lic] Insinööritieteiden korkeakoulu / ENG
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- Evaluation of three ice-structure interaction models
Licentiate thesis(1996) Muhonen, AriThis work concentrates on the contact between an ice edge and a vertical indenter face during intermittent crushing. The results of a laboratory indentation test series are analyzed and a description of the physical phenomena occurring at the contact is given. The existing dynamic ice-structure interaction models are reviewed. The ability of three models to simulate representative test results is evaluated. The results of the indentation test series consist of 77 tests of which 23 are analyzed. The tests were carried out in a small basin with a floating sheet of columnar grained freshwater ice. The ice was horizontally loaded with an indenter which was installed in front of a spring-mass system. Special attention was paid to the visual observations in order to find the physical phenomena occurring at the ice deformation process. The ice failure process was cyclic in the whole analyzed parameter space. The apparent crushing frequency was dependent on the indenter velocity and the lowest natural frequency of the structure. The latter also affected the peak force values: the higher the natural frequency the lower the force. The ice failed in flaking. The flakes were formed locally by different size macrocracks which separated the flakes from the parent ice. This lead to a chain reaction which caused the deformation of the whole contact face during the load drop. The resulting ice wedge was crushed during the spring-back phase following the load drop. The results of three representative tests were simulated using three different type dynamic ice-structure interaction models. None of the models performed well when the needed parameter values were obtained straight from the tests or the test conditions. However, when the parameter values were modified, the match improved considerably. - Metalli-lasirakenteisen kaksoisjulkisivun materiaalien soveltamiskriteerit
Licentiate thesis(2003) Tenhunen, OlaviThis thesis deals with criteria for application of materials to a façade that is covered by a separate glass casing. Some materials may be connected to a particular structure or detail. Criteria may concern building physics, architecture, lighting or structures. Criteria in building physics include factors concerning heat, noise and humidity, which are influenced by radiation, absorption and reflection of light and heat, by sound transmission, air permeability and shelter against rain. Lighting criteria may be such as means to affect quantity and quality of light e.g. selecting materials on the grounds of transmission, reflection, scattering and discoloration of light and their control. Architectural criteria are related to using characters of materials so that appearance and operation of building will stay satisfactory, also when circumstances vary. Structural criteria are related to capacity, safety, security, service and structural functioning. Criteria may also be economical like construction and operating costs. By criteria it is possible to specify the usability of materials in a double glazed façade, what kind of materials and on what ground they have to be used and how these must be applied so that they will operate satisfactorily. Criteria will be specified resulting from needs of parties involved in building, and are typically individual for every double skin façade. This thesis deals with factors to be taken into account in criteria and their background. - Kiviset kulissit - Menneisyyden ja nykyhetken vuoropuhelu eteläitalialaisessa agrokaupungissa
Insinööritieteiden ja arkkitehtuurin tiedekunta | Licentiate thesis(2009) Huovinen, KatjaTutkimuksen ensimmäinen osa, Kiveen kirjoitettu historia, on lähestymistavaltaan ja metodiltaan lähinnä perinteistä arkkitehtuurin historiaa. Se taustoittaa alueen historiaa ja tutkimuskohteena olevaa kaupunkia. Kuvattuani tutkimuskentälle saapumista ja ensivaikutelmia luonnostelen asukkaiden identiteettiä ja sitä mitä heille itselleen merkitsee olla Etelästä. Esitän lyhyesti Etelä-Italian pitkän historian, ja Salenton alueen aseman siirtyvän keskipisteen periferiassa. Luvussa annan esimerkkejä siitä miten Etelä-Italian kaupungeissa näkyy alueen historia ja elinkeinorakenne. Erityisen huomion ansaitsee kaupunkirakenteen samankaltaisuus islamilaisen maailman kaupunkien kanssa. Laajemman kontekstin esittelyn jälkeen keskityn tutkimuksen toisessa luvussa varsinaiseen tutkimuskohteeseeni. Tutkimuksen toisessa osassa Pelin säännöt selvitän ja selitän diskurssissa toistuvia sosiaalisen elämän pelisääntöjä, julkista ja yksityistä, kunniaa ja sen puutetta, joita tuntematta tilan sosiaalista tuottamista on vaikea ymmärtää. Kuvaan kaupunkitilan jäsentymistä ja jakaantumista julkiseen, puolijulkiseen, puoliyksityiseen ja yksityiseen. Yksityisen ja julkisen raja on diskurssissa häilyvä. Kyky rajanvetoon nähdään sivistyksenä, civilta; sen vastakohtana on sivistyksen puute, takapajuinen elämäntapa. Yksityistymisen asumiselle asettamat vaatimukset heijastuvat muutospaineena kaupunkitilassa. Sekä kaupunkitilassa että kodeissaan asukkaat ylläpitävät sosiaalista julkisivua; teatterimetaforaa voisi kritikoida kysymällä onko kyseessä elämä vai näytelmä, mutta näytelmän henkilöhahmot ottavat roolinsa tosissaan. Kolmas osa Näyttämöllä ja kulisseissa kuvailee edellisessä osassa esiin tuotujen pelisääntöjen toteutumista rakennetussa ympäristössä. Keskeisiä käsitteitä ovat tilan järjestyminen sukulaisuuden, myötäjäis- ja perintöstrategioiden mukaan sekä sukupuolitettu tila. Palaan detaljitasolla tarkastelemaan jo ensimmäisessä luvussa esitettyä Etelän kaupunkirakennetta alueelle luonteenomaisen sisäpihallisen kaupunkitalon muodossa. Sosiaalisen elämän pelisäännöt heijastuvat asunnon symbolisessa järjestyksessä. Neljäs osa Muuttuva kaupunki käsittelee lähimenneisyydessä tapahtunutta, yhä käynnissä olevaa muutosta ja sen takana vaikuttaneita ihanteita ja arvotuksia. Kaupungin rakenne säilyttää muistoja ja vastustaa muutosta, mutta samanaikaisesti epäjatkuvuuden tai murroksen jäljiltä muuttunut kaupunki tekee vaikeaksi ellei peräti mahdottomaksi paluun entiseen. Muutos näyttäytyy kaksisuuntaisena liikkeenä: ensin 1800-luvun lopulta alkaen kaupunkirakenteen muureja ympäröivälle maaseudulle levittävänä keskipakoisena voimana, myöhemmin 1900-luvun viimeisinä vuosikymmeninä ainakin diskurssin tasolla ilmenneenä vanhan rakennuskannan uutena arvostuksena. Päätän tutkimuksen lyhyeen pohdintaan vanhankaupungin tulevaisuudesta. - Engineering characteristics of cement stabilized soft Finnish clay
School of Engineering | Licentiate thesis(2009) Hassan, Md. Mamunul - Kiinteistösijoitukset suomalaisten institutionaalisten sijoittajien salkuissa - suoran ja välillisen kiinteistösijoittamisen allokointi ja kehitys lähitulevaisuudessa
Insinööritieteiden korkeakoulu | Licentiate thesis(2009) Leinonen, JaakkoThe background of the study consist of the development of the indirect real estate investment. Main objective of the study was to describe the role of the real estate investments (direct and indirect) as part of the portfolio of the institutional investors and the development in the near future. Sub goals were to explain the development of the real estate market, define the factors which affect to the changes of the real estate allocation and clarify the changes of the real estate investments of the Finnish institutional investors. Methods were Semi-structured interviews , questionnaires and literature. This study is more inductive than deductive research. This study might be clarified as the explorative study. Results were proving following. International real estate market has been developed rapidly during last years. This phenomenon has influenced also to Finnish property market. Finnish institutional investors have been important group in the Finnish property market despite of the several new international investors in Finland. Real estate investment is the asset class which provides stable return and stabilize the portfolio. Conclusions of the study were that Finnish institutional investors will increase their real estate investments in the future because real estate allocations will be kept in the same level in the future and the pension funds will increase from 15 to 20 years. The increase of the real estate investment portfolio will be done mostly via indirect real estate investment instruments. Approximately 30-50 % will be invested to Finland and 50-70 % to abroad. The real estate portfolios of the Finnish institutional investors will be approximately double sized during the following 15 to 20 years. Practical contribution of the study is that it has described the development of the real estate market, how these changes might affect to different players in the real estate business and which factors are important in the investment process of the real estate funds. - Fundamentals of air curtain design
School of Engineering | Licentiate thesis(2010) Valkeapää, AkiAir curtains are used to reduce doorway-induced thermal losses and the negative effects of draught in situations where ordinary fixed doors are kept open. This paper examines the functionality of air curtains, and related factors, with the aid of measurements made in industrial buildings. To clarify the operating conditions of air curtains, an analysis method was developed during the project based on field research and measurements. In addition, the paper sets out horizontal and vertical upwards blowing air curtains' tightness levels defined with tracer measurement results as the basis. Tightness measurements were conducted to study the energy saving effects of air curtains under the climatic conditions of Finland. The results are presented with the aid of an example calculation in the final section of this paper. When using an air curtain under the correct operating conditions, the achievable tightness is 50 - 80 % in large doorways. The highest tightness level was obtained in the test hall when using an upwards blowing air curtain of the recirculating type (etaac,maxac,max - Process integration in mechanical pulp and paper mills - Comparison of selected methods in industrial examples
School of Engineering | Licentiate thesis(2010) Ruohonen, PekkaIn a world of rising energy prices and tightening limits on CO2 emissions, it is becoming more and more important to consider energy efficiency in industry. When considering the current trends in globalisation and structural changes in all industrial fields, it is clear that in industrialised countries the focus will shift more and more from green field to retrofit projects. Many retrofit projects have been carried out m recent years, but there is still great potential to reduce primary energy consumption. One important aspect is the design of heat exchanger networks. This thesis presents a literature review of the different methodologies used in heat exchanger network design, and a comparison of two of them m industrial examples. The studies show that the advanced composite curves give a lot more information on the studied system than traditional pinch-based methods. The whole mill can be shown in two diagrams, one above and the other below pinch that show at a glance how the existing heat exchanger network is designed compared to theoretical possibilities. The real temperature levels of the utilities used at the mill, and the theoretical upper and lower level for those temperatures, shown together in the curves give guidance to the engineer as to where to look for improvement potential. The method should be widely implemented in the industry. - Kotelopalkkisillan vääristyminen taivutus- ja vääntökuormituksessa
School of Engineering | Licentiate thesis(2010) Syrjä, RistoIn this thesis, distortion of a box girder bridge is studied. A vertical eccentric traffic load is divided into symmetric and antimetric part by the principle of superposition. The first one is causing bending and the latter one torsion. Distortion in the both loading cases is studied separately. The model of the structure is created by dividing the girder into transverse parts. Then a longitudinally infinitesimal long strip is considered. The strip is further divided into parts horizontally. To these parts the equilibrium and compatibility conditions are applied. By this procedure, the frame effect and longitudinal distribution of forces of the box girder are taken into account. An equation group is obtained from compatibility and equilibrium conditions, where constitutive conditions are taken into account. From the equation group the differential equation of the selected deformation can be derived. The theory is derived without using warping functions and a sectorial coordinate used in thin-walled beam theory. The study is restricted to relate a single-cell; straight box girder with straight supports (perpendicular to the longitudinal direction). The cross-section is uniform in the longitudinal direction and symmetric with respect to the vertical axis. The deck has two side cantilevers. The webs are in vertical direction. Material is uniform in each structural part, which is the deck, two webs and the lower flange, but it can be diverse between the parts. The theory is available for a composite structure as well. The loading is vertical and it is acting on the deck. In the case of symmetric loading it is noticed, that the behaviour of the structure may be divided into two independent parts, i.e. bending and distortion. For the case of the latter one, the differential equation of the horizontal deflection of the web gravity centre and its solution in the case of point road and uniformly distributed load are derived. As far as known, the equation representing distortion in the case of symmetric loading is not presented earlier. The results of the analytical solution in the case of symmetric loading are compared to the results obtained by a finite element analysis. The theory is superimposed to a single-span bridge with butt diagrams at the support lines. In the case of antimetric loading, the differential equation group is derived. In this equation group all equations are dependent on each other, and that is why it is not possible to divide this group into two independent parts. Because of the extent of this work, the derivation of the differential equation and its application is left to the challenge of a complementary research. - Condition management of water distribution systems
School of Engineering | Licentiate thesis(2010) Aksela, KiaThis thesis discusses technical condition management of a water distribution network. The main components of condition management are condition management of the network's assets, hydraulic performance management and water quality management. The ultimate goal is to secure water quality, maintain the service level and to utilise resources in a sensible way with an acceptable level of risk. The techniques and methods utilised today are outdated and do not support proactive condition management - currently only a reactive approach is commonly applied. Before condition management can truly evolve, improvements need to be made in hydraulic management. The most significant contributions of this work are the two methods developed in it. The first is a novel, automated, indirect leakage detection method, which utilizes flow measurement data from the network supplied by a supervisory control and data acquisition system. The second is a new way to perform customer demand estimation based on the sample measurements of residential customers using an automated meter-reading technique. Leakage information aids directly in condition management as it is used as one variable in describing the condition of assets. Demand and leaks combined constitute the load to the network. As the least information is available on the load, its better quantification opens new possibilities in hydraulic calculations. The developed solutions build upon a new approach in the field of network hydraulic management and furthermore in assets condition management. The prevailing techniques are presented briefly and future requirements are established. As a high level contribution, a path towards more effective technical management of the network is shown. The traditional static information is combined with dynamic information 50 that more comprehensive assessment of water distribution system performance and condition can be formed. - Biologinen typen- ja fosforinpoisto jätevesistä - Nitrifikaation tehostaminen vapaasti kelluvilla kantoainekappaleilla
School of Engineering | Licentiate thesis(2010) Rantanen, PirjoThe 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. - Optical measurements of diesel fuel spray on medium speed engine
School of Engineering | Licentiate thesis(2011) Sarjovaara, TeemuThis 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. - Vapaasti seisovat poikkileikkaukseltaan kolmionmuotoiset ristikkotornit
School of Engineering | Licentiate thesis(2011) Lehtinen, AlpoThis 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. - Jäähdytetyn myymäläkalusteen rakenteelliset ja toiminnalliset parametrit
School of Engineering | Licentiate thesis(2011) Sipilä, Tomi T.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. - Teollisen tuotannon sivuainevirtojen hyödyntäminen - ajurit, esteet ja yrityksen liiketoimintamahdollisuudet
School of Engineering | Licentiate thesis(2011) Pajunen, Nani - Structural lifetime, reliability and risk analysis approaches for power plant components and systems
School of Engineering | Licentiate thesis(2011) Cronvall, OtsoLifetime, 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. - One solution fits all? Differences in work environment preferences of office occupiers
School of Engineering | Licentiate thesis(2011) Rothe, PeggieSatisfaction, 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. - Hardness prediction of a laser hybrid welded joint using FE simulation
School of Engineering | Licentiate thesis(2011) Tamminen, Tero - Advanced heat transfer modelling with application to internal combustion engine CFD simulations
School of Engineering | Licentiate thesis(2011) Nuutinen, MikaAt 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. - Vastuun kantajat - Asunto-osakeyhtiön hallituksen jäsenen vastuu ja sen aktualisoituminen
School of Engineering | Licentiate thesis(2011) Malk, MarkusThe 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. - Managing integration of company mergers and acquisitions in particular in cross cultural construction project business
School of Engineering | Licentiate thesis(2011) Lönnrot, TuijaThe 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).