Two-phase flow measurements with spacer grid in a rod bundle geometry

Heat transfer effectiveness in nuclear rod bundles is of great importance to nuclear reactor safety and economics. An important design parameter is the Critical Heat Flux (CHF), which limits the transferred heat from the fuel to the coolant. The CHF is determined by flow behaviour, especially the turbulence created inside the fuel rod bundle. Adiabatic experiments can be used to characterize the flow behaviour separately from the heat transfer phenomena in diabatic flow. To enhance the turbulence, mixing vanes are attached to spacer grids, which hold the rods in place. The vanes either make the flow swirl around a single sub-channel or induce cross-mixing between adjacent sub-channels. In adiabatic two-phase conditions an important phenomenon that can be investigated is the effect of the spacer on canceling the lift force, which collects the small bubbles to the rod surfaces leading to decreased CHF in diabatic conditions and thus limits the reactor power. Computational Fluid Dynamics (CFD) can be used to simulate the flow numerically and to test how different spacer configurations affect the flow. Experimental data is needed to validate and verify the used CFD models. Especially the modeling of turbulence is challenging even for single-phase flow inside the complex sub-channel geometry. In two-phase flow other factors such as bubble dynamics further complicate the modeling. To investigate the spacer grid effect on two-phase flow, and to provide further experimental data for CFD validation, a series of experiments was run on an adiabatic sub-channel flow loop using a duct-type spacer grid with different configurations. Utilizing the wire-mesh sensor technology, the facility gives high resolution experimental data in both time and space. The experimental results indicate that the duct-type spacer grid is less effective in canceling the lift force effect than the egg-crate type spacer tested earlier.

Fundraising and investor relations in social enterprise: Marketing your way out of the pioneer gap in African off-grid renewable energy

Social enterprises apply the best of business for the pursuit of social or environmental mission while also generating revenues. Globally, nearly 1,3 billion people lack access to electricity, as well as another billion having access to only low quality and infrequent electricity. Off-grid renewable energy, like solar, will increasingly have a key role in the solution of the energy access issue. The pioneer gap in off-grid renewable energy consists of financing (or funding) gaps and capacity gaps, to do with both the early stage of the enterprises in question, as well as the early stage of the whole industry. The gaps are emphasised by specific characteristics of off-grid renewable energy business models and the requirements of operating in bottom-of-the-pyramid markets. The marketing perspective to fundraising is chosen to uncover the possible role enterprises themselves have in bridging the pioneer gap. The purpose of this thesis is to study how social enterprises operating in off-grid renewable energy in Africa utilise marketing activities in their investor relations in bridging the pioneer gap. This main research question is divided into the following sub-questions:  How does the pioneer gap affect fundraising for these enterprises?  How are the funding needs for these enterprises characterised?  How do these enterprises build trust in their investor relations? The theoretic framework is built on relationship marketing and investor relations, with an emphasis on creation of trust. The research is conducted as a thematical case study. Primary data is gathered via semi-structured interviews with six solar energy companies and two accelerators. According to the findings, the main components affecting trust-creation are diminished information asymmetry and perceived risk, mission alignment as well as a personal fit or relationship with the investor. Therefore, an enterprise can utilise e.g. the following marketing activities in their investor relations to bridge the pioneer gap: ensuring investor material, the enterprise story and presenting of them is clear, concise and complete to “package” the enterprise as an investment; taking investor needs and motivations into account as well as utilising existing investors as ambassadors.

Piilevien asiakastarpeiden tunnistaminen – repertory grid -tekniikka

Tässä työssä tutkitaan asiakaslähtöisyyttä tuotekehityksessä ja piilevien asiakastarpeiden selvittämistä ja hyödyntämistä asiakaslähtöisyydessä. Tavoitteena on selvittää asiakaslähtöisyyden tärkeyttä ja etuja tuotekehityksessä, sekä käydä läpi erilaisia asiakastarpeiden selvittämismetodeja erityisesti keskittyen repertory grid –tekniikkaan (RGT). Asiakaslähtöisyys tuo yrityksille merkittävää kilpailuetua tuotekehityksen alkupäähän. Erityisesti piilevät asiakastarpeet voivat mahdollistaa tuoteinnovaatioita, joilla saavutetaan huomattavasti parempaa asiakastyytyväisyyttä ja etulyöntiasemaa kilpailijoihin nähden. Piileviä asiakastarpeita voi tunnistaa repertory grid –tekniikalla, jota on avattu tässä työssä. Tekniikka mahdollistaa piilevien asiakastarpeiden tunnistamisen, mikä osaltaan edistää etulyöntiaseman antavia asiakaslähtöisiä tuoteinnovaatioita, joilla yritys voi differoitua muista markkinoilla olevista yrityksistä. Asiakaslähtöisyyden tulee tuotekehityksen lähtökohdan lisäksi olla osa yrityksen strategiaa ja kulttuuria, jotta yritys voi menestyä asiakaslähtöisyydellä.

Modular Double-Cascade Converter

Medium-voltage motor drives extend the power rating of AC motor drives in industrial applications. Multilevel converters are gaining an ever-stronger foothold in this field. This doctoral dissertation introduces a new topology to the family of modular multilevel converters: the modular double-cascade converter. The modularity of the converter is enabled by the application of multiwinding mediumfrequency isolation transformers. Owing to the innovative transformer link, the converter presents many advantageous properties at a concept level: modularity, high input and output power quality, small footprint, and wide variety of applications, among others. Further, the research demonstrates that the transformer link also plays a key role in the disadvantages of the topology. An extensive simulation study on the new converter is performed. The focus of the simulation study is on the development of control algorithms and the feasibility of the topology. In particular, the circuit and control concepts used in the grid interface, the coupling configurations of the load inverter, and the transformer link operation are thoroughly investigated. Experimental results provide proof-of-concept results on the operation principle of the converter. This work concludes a research collaboration project on multilevel converters between LUT and Vacon Plc. The project was active from 2009 until 2014.

Nova et accuratissima tabula regionum ad Sinum Finnicum. Exactissimo delineata ac sumneo studio recognito ab Henrico de Leth.

[N. 1:1200000].

Tabvla Rvssiae ex autographo, quod delineandum curavit Foedor filius tzaris Boris desumta; et ad fluvios Dwinam, Zuchanam, aliaque loca, quantum ex tabulis et notitiis ad nos delatis fieri potuit, amplificata: ac magno domino, tzari , et magno duci Michäeli Foedorowits omnium Russorum, autcratori Wolodimeriae, Moscoviae et Novogardia. Tzari Cazaniae, tzari Astracaniae, tzari Siberiae, domino Plescoviae magno duci Smolenscoviae, Otweriae, Iugoriae, Permiae, Wiatkiae, Bulgariae etc: domino regionum Iveriae Kartalinie et Groesiniae tzari etc: dedicata ab Hesselo Gerardo M.DC.XIIII.

[N. 1:9000000].

Europa religionis christianae, morum, et pacis ac belli artium cultu omnium terrar: orbis partiu[m] praesantiß: juxta recent[issi]ma exempl: accurat[issi]ma excusa a Matth. Seuttero s. c. m. geogr.

[N. 1:27000000].

Nova mappa geographica Sueciae ac Gothiae regna ut et Finlandiae ducatum ac Lapponiam, cum provinciis minoribus, ob oculos ponens, cura et sumtibus Tobiae Conradi Lotter, chalcogr et geogr: Augustae Vindel.

Alareunassa privilegiomerkintä: Cum gratia et privil. s. r. i. vicariatq, in partibq Rheni, Sveviae, et juris Franconici.

De Spiritu Sancto, et aeterna eius divinitate ac processione; nec non officio atque donis

Invokaatio: Sun to Theo trisbeltiso kai megiso.

Fasciculus physicae ejusdem illustriores definitiones, divisiones, atque nobiliores controversias axiomatibus nonnullis insertas brevibusque rationibus firmatas ac enodatas continens

Arkit: 4 arkintunnuksetonta lehteä, A-F8 G4.

Zetémata quaedam ex spatioso ac fructuoso philosophiae agro excerpta

Invokaatio: Cum Deo.

De theologiae natura, ad decretum venerandae facultatis theologicae, moderatore plurimum reverendo, amplissimo ac praeclarissimo dn. Abrahamo Thauvonio, s. s. theol. doctore & professore ord: p. t. magnifico rectore, boni ominis [!] causa, ante introductionem suam disputabit Petrus Bång Hels. In auditorio majore die 9. Decemb. anno 1665

Invokaatio: I.N.J.

Themata nonnulla theoretica simul ac practica duabus sectionibus inclusa

Invokaatio: Auxilio Jehovae.

Positiones philosophicae ex fragrantissimo philosophiae viridario carptìm collectae. Quas ex consensu amplissimae [et] venerandae facultatis philosophicae in Regiâ Academiâ Aboënsi. Sub praesidio, ... dn. Michaelis Gyllenstålpes, Wexionii, j. u. & philos: doct: pereximii, ll:m polit: & hist: prof: publ: celeberrimi, p. t. rectoris magnifici, moecenatis, praecept. ac promotoris quovis obsequii & honoris genere plurimùm prosequendi. Liberalis exercitij gratia, publicae eruditorum disquisitioni modestè sistit Daniel B. Rosander Smolandus s. r. m.tis stipendiarius. In auditorio majori ad diem 22. Novemb. anno 1654. Horis ab 8. antemeridianis

Variantti A.

De Sveo-Gothis; qui vixerunt sub periodo Erici I.mi. ad Ericum 2.dum: memorans quomodo restituti sunt primum ab Erico, mox tamen ac multos annos ab incertis ducibus vexati, at nunquam vera religione destituti

Variantti B.