Cold hardiness research on agricultural and horticultural crops in Finland

Selostus: Pelto- ja puutarhakasvien kylmänkestävyystutkimus Suomessa

Fatigue Analysis of Welded Cruciform Joints with Cold Laps

Työssä on tutkittu vetojännityskuormituksen alaisena olevien hitsattujen kuormaa kantamattomien X-liitosten hitsin paikallisen geometrian variaation vaikutusta väsymislujuuteen. Muuttujina olivat reunan pyöristyssäde, kylmäjuoksun suuruus ja kylkikulma. Geometristen muuttujien parametrinen riippuvuussuhde on analysoitu usealla elementtimallilla. Väsymistarkastelu on suoritettu käyttämällä lineaaris-elastista murtumismekaniikkaa (LEFM) tasovenymätilassa ja materiaalina terästä. Särönkasvun suunnan ennustamisessaon käytetty maksimipääjännityskriteeriä sekä jännitysintensiteettikertoimet on määritetty J-integraalilla. Särön ydintymisvaihetta ei ole otettu huomioon. Rakenteen on oletettu olevan hitsatussa tilassa ja jännitysheilahdus on kokonaan tehollinen. Särön kasvunopeuden ennustamiseen on käytetty Paris'n lakia. Väsymislujuustulokset on esitetty karakteristisina väsymisluokkina (FAT) ja sovitettu parametriseksi yhtälöksi. Lopuksi väsymisanalyysin ennustamia tuloksia on verrattu saatavilla oleviin väsytystestituloksiin.

The Role and Measurement of Social Capital in New Technology-Based Start-up Context

Tämän Pro gradu-tutkielman tavoitteena olirakentaa esiymmärrys sosiaalisen pääoman roolista ja mittaamisesta uuden teknologian start-up yrityksissä. Pääasiallisena tarkoituksena tässä tutkimuksessa olilöytää sosiaalisen pääoman ja start-up yrityksen tuloksellisuuden välille yhdistävä tekijä. Tutkimuksen empiirinen aineisto kerättiin pääasiallisesti kuuden OKO Venture Capitalin sijoitusportfolioon sisältyvien case-yritysten kvalitatiivisten teemahaastatteluiden sekä kvantitatiivisten kyselylomakkeiden avulla. Kvalitatiivisten haastatteluiden tulosten perusteella sosiaalisen pääoman ja tuloksellisuuden välille löytyi yhdistävä tekijä, jota käytettiin myöhemmin hyväksi kvantitatiivisessa kyselylomakkeessa. Tämän tutkielman tulokset osoittivat, että startegisen päätöksenteon kautta sosiaalinen pääoma vaikuttaa osittain start-up yritysten tuloksellisuuteen. Manageriaalisesti tärkempi löydös tässä tutkimuksessa oli kuitenkin se, että sosiaalista pääomaa voidaan käyttää hyväksi ennustettaessa uuden teknologian start-up yritysten tulevaisuuden kassavirtoja.

Effect of Noncondensable Gases on Circulation of Primary Coolant in Nuclear Power Plants in Abnormal Situations

The present study focuses on two effects of the presence of a noncondensable gas on the thermal-hydraulic behavior of thecoolant of the primary circuit of a nuclear reactor in the VVER-440 geometry inabnormal situations. First, steam condensation with the presence of air was studied in the horizontal tubes of the steam generator (SG) of the PACTEL test facility. The French thermal-hydraulic CATHARE code was used to study the heat transfer between the primary and secondary side in conditions derived from preliminary experiments performed by VTT using PACTEL. In natural circulation and single-phase vapor conditions, the injection of a volume of air, equivalent to the totalvolume of the primary side of the SG at the entrance of the hot collector, did not stop the heat transfer from the primary to the secondary side. The calculated results indicate that air is located in the second half-length (from the mid-length of the tubes to the cold collector) in all the tubes of the steam generator The hot collector remained full of steam during the transient. Secondly, the potential release of the nitrogen gas dissolved in the water of the accumulators of the emergency core coolant system of the Loviisa nuclear power plant (NPP) was investigated. The author implemented a model of the dissolution and release ofnitrogen gas in the CATHARE code; the model created by the CATHARE developers. In collaboration with VTT, an analytical experiment was performed with some components of PACTEL to determine, in particular, the value of the release time constant of the nitrogen gas in the depressurization conditions representative of the small and intermediate break transients postulated for the Loviisa NPP. Such transients, with simplified operating procedures, were calculated using the modified CATHARE code for various values of the release time constant used in the dissolution and release model. For the small breaks, nitrogen gas is trapped in thecollectors of the SGs in rather large proportions. There, the levels oscillate until the actuation of the low-pressure injection pumps (LPIS) that refill the primary circuit. In the case of the intermediate breaks, most of the nitrogen gas is expelled at the break and almost no nitrogen gas is trapped in the SGs. In comparison with the cases calculated without taking into account the release of nitrogen gas, the start of the LPIS is delayed by between 1 and 1.75 h. Applicability of the obtained results to the real safety conditions must take into accountthe real operating procedures used in the nuclear power plant.

Venture Capital: How to Valuate Infocom Start-ups?

Tutkimuksen tavoitteena oli selvittää kuinka Infocom -alan käynnistysvaiheen yrityksiä voi arvioida pääomasijoitustoiminnassa. Pääomasijoittajien käyttämät arviointikriteerit selvitettiin kirjallisuuskatsauksen ja empiirisen osion avulla. Koska Infocom -alan käynnistysvaiheen omaisuuserät ovat pitkälti aineettomia, arviointikriteerit muodostavat pohjan yrityksen arvioinnille. Tutkimuksessa vertailtiin myös erilaisia arvonmääritysmenetelmiä ja niiden käyttökelpoisuutta Infocom alan käynnistysvaiheen yritysten arvonmäärityksessä. Tutkimuksen mukaan Infocom alan käynnistysvaiheen yritysten arvioiminen ja arvonmääritys perustuu pitkälti aineettomien omaisuuserien arviointiin: inhimillinen pääoma, suhde-, innovaatio- ja kehityspääoma ovat näiden yritysten tärkeimmät aineettomat omaisuuserät. Infocom -alan käynnistysvaiheen yritysten arvonmääritykseen ei ole olemassa yhtä universaalia työkalua, vaikka reaalioptio-teoria tuokin käyttökelpoisen näkökulman myös käynnistysvaiheen yritysten arviointiin. Tämän vuoksi aineettomien omaisuuserien arviointi ja mittaaminen, tulevaisuudessa myös niiden arvonmääritys, on tärkein lähtökohta onnistuneille Infocom alan käynnistysvaiheen yritysten arvonmäärityksille.

Calculation of the critical crack size for cold form rectangular hollow section tube (CRHS) under bending load at -40º C temperature

To predict the capacity of the structure or the point which is followed by instability, calculation of the critical crack size is important. Structures usually contain several cracks but not necessarily all of these cracks lead to failure or reach the critical size. So, defining the harmful cracks or the crack size which is the most leading one to failure provides criteria for structure’s capacity at elevated temperature. The scope of this thesis was to calculate fracture parameters like stress intensity factor, the J integral and plastic and ultimate capacity of the structure to estimate critical crack size for this specific structure. Several three dimensional (3D) simulations using finite element method by Ansys program and boundary element method by Frank 3D program were carried out to calculate fracture parameters and results with the aid of laboratory tests (loaddisplacement curve, the J resistance curve and yield or ultimate stress) leaded to extract critical size of the crack. Two types of the fracture which is usually affected by temperature, Elastic and Elasti-Plastic fractures were simulated by performing several linear elastic and nonlinear elastic analyses. Geometry details of the weldment; flank angle and toe radius were also studied independently to estimate the location of crack initiation and simulate stress field in early stages of crack extension in structure. In this work also overview of the structure’s capacity in room temperature (20 ºC) was studied. Comparison of the results in different temperature (20 ºC and -40 ºC) provides a threshold of the structure’s behavior within the defined range.

Wind turbine operation in cold climate

The goal of the master‘s thesis is to determine and estimate ice accretion influence on the wind turbine blade performance. The thesis describes the technique of ice accretion calculation on the wind turbine blade and determination characteristics of the turbine with ice accreted. The methodology of the classic Blade Element Moment Theory was used. Iced blade experimental data was investigated in order to calculate blade with ice characteristics. The obtained results shows that iced blade power coefficient is lower than clean blade one. The heating system implementation shows that in the particular site in the Lapland region it is efficient.

Exiles and Constituents: Baltic Refugees and American Cold War Politics, 1948- 1960

This dissertation explores the complicated relations between Estonian, Latvian, and Lithuanian postwar refugees and American foreign policymakers between 1948 and 1960. There were seemingly shared interests between the parties during the first decade of the Cold War. Generally, Eastern European refugees refused to recognize Soviet hegemony in their homelands, and American policy towards the Soviet bloc during the Truman and Eisenhower administrations sought to undermine the Kremlin’s standing in the region. More specifically, Baltic refugees and State Department officials sought to preserve the 1940 non-recognition policy towards the Soviet annexation of the Baltic States. I propose that despite the seemingly natural convergence of interests, the American experiment of constructing a State-Private network revolving around fostering relations with exile groups was fraught with difficulties. These difficulties ultimately undermined any ability that the United States might have had to liberate the Baltic States from the Soviet Union. As this dissertation demonstrates, Baltic exiles were primarily concerned with preserving a high level of political continuity to the interwar republics under the assumption that they would be able to regain their positions in liberated, democratic societies. American policymakers, however, were primarily concerned with maintaining the non-recognition policy, the framework in which all policy considerations were analyzed. I argue that these two motivating factors created unnecessary tensions in American policy towards the Baltic republics in the spheres of psychological warfare as well as exile unity in the United States and Europe. Despite these shortcomings, I argue that out of the exiles’ failings was born a generation of Baltic constituents that blurred the political legitimacy line between exiles who sought to return home and ethnic Americans who were loyal to the United States. These Baltic constituents played an important role in garnering the support of the United States Congress, starting in the 1950s, but became increasingly influential after the 1956 Hungarian Revolution, despite the seemingly less important role Eastern Europe played in the Cold War. The actions of the Baltic constituents not only prevented the Baltic question from being forever lost in the memory hole of history, but actually created enough political pressure on the State Department that it was impossible to alter the long-standing policy of not recognizing the Soviet annexation of the Baltic States.

Rediscovering profitability in entrepreneurship : evidence from Finnish high-technology start-ups

Denna avhandling utmanar sambandet mellan tillväxt och lönsamhet. Lönsamhet, som borde vara företagens största prioritet har nästan totalt försvunnit från entreprenörskapsfältet. Istället har den blivit ersatt av en fokus på tillväxt och framförallt hög tillväxt. Den nuvarande allmänna normen verkar vara att tillväxt blint prioriteras över lönsamhet. Detta beror på det förvrängda sambandet mellan tillväxt och lönsamhet; antagandet att hög tillväxt förr eller senare kommer att leda till hög lönsamhet. Således ses tillväxt som ett mått på ett företags framgång och som ett mål värt att eftersträva. Det har blivit fokuset i allmän media och entreprenörskapsforskning, något beslutfattarna försöker stöda och uppmuntra, entreprenörerna vill uppnå och finansiärerna vill skapa. Allt detta, oftast på bekostnad av lönsamhet. Denna avhandling strävar efter att få en ändring på detta genom att utmana denna nuvarande norm. Avhandlingens empiriska del fokuserar sig på nya finska högteknologiföretag inom bio- och IT-branschen. Tillväxtfenomenet studeras i tre olika kontexter: forskningen (en analys på 118 artiklar i ledande entreprenörskaps och managementjournaler), praktiken (en finansiell analys på 1039 nya företag) och bland intressenternas perspektiv (23 intervjuer med entreprenörer, beslutsfattare, offentliga finansiärer och riskfinansiärer). Resultaten bekräftar en stark förvrängning av tillväxt och lönsamhet inom de tre studerade kontexterna. Den finansiella analysen bekräftar resultaten av senare forskning och visar att lönsamhet, istället för tillväxt, är förutsättningen för fortsatt lönsam tillväxt. Resultaten stämmer oberoende av företagens ålder. Det visas även att en ändring i strategisk position är osannolik och mycket svår att genomföra. Detta lyfter fram nödvändigheten för startade företag att fokusera sig på rätt saker genast från start; skapandet av en lönsam affärsmodell.

Finnish Institutional Innovation Support Policies from Russian Entrepreneurs' Perspective: Establishing Cross-Border Technology Oriented Start-Up Firm

The purpose of this thesis is to study how Russian entrepreneurs perceive Finnish institutional environment and innovation support policies provided in the country, as well as to present a practical example in form of a case study of one technology oriented start-up firm which was established in Finland by Russian entrepreneurs. The empirical research of the thesis is conducted qualitatively in two parts. First part is conducted through online questionnaire with open questions in order to review the perceptions of Russian entrepreneurs in general. Second part is based on personal interviews with case company’s founders with the focus on the process of establishing the company in Finland. In the first part of the empirical research, five Russian start-up firms were contacted, and four responses were received. All of these responses were qualified for further analysis. The findings of the first part of the research reveal that Russian entrepreneurs have rather positive attitudes towards Finnish institutional innovation support policies. However, most of the entrepreneurs stated that they are unlikely to create their presence in Finland. As an outcome of the second part of the research, the process of establishing a case company in Finland is illustrated. In order to be able to establish companies in Finland, Russian entrepreneurs who have a permanent residence outside European Economic Area (EEA) are required to apply for a permission to perform business operations in the country. In addition, the established company must engage in improving the economical stand of the country by creating new work places, raising tax revenues, develop technologies and generate innovations in the country.

Spin-Dynamics in Cold Gases of 87Rb and Atomic Hydrogen. The spins they are a-changin’

In this thesis the dynamics of cold gaseous atoms is studied. Two different atomic species and two different experimental techniques have been used. In the first part of the thesis experiments with Bose-Einstein condensates of Rb-87 are presented. In these experiments the methods of laser cooling and magnetic trapping of atoms were utilized. An atom chip was used as the experimental technique for implementation of magnetic trapping. The atom chip is a small integrated instrument allowing accurate and detailed manipulation of the atoms. The experiments with Rb-87 probed the behaviour of a falling beam of atoms outcoupled from the Bose-Einstein condensate by electromagnetic field induced spin flips. In the experiments a correspondence between the phases of the outcoupling radio frequency field and the falling beam of atoms was found. In the second part of the thesis experiments of spin dynamics in cold atomic hydrogen gas are discussed. The experiments with atomic hydrogen are conducted in a cryostat using a dilution refrigerator as the cooling method. These experiments concentrated on explaining and quantifying modulations in the electron spin resonance spectra of doubly polarized atomic hydrogen. The modifications to the previous experimental setup are described and the observation of electron spin waves is presented. The observed spin wave modes were caused by the identical spin rotation effect. These modes have a strong dependence on the spatial profile of the polarizing magnetic field. We also demonstrated confinement of these modes in regions of strong magnetic field and manipulated their spatial distribution by changing the position of the field maximum.