106 resultados para super-orbital re-entry
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Kartta kuuluu A. E. Nordenskioldin kokoelmaan
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Lisakartta: Plan et vue des terres du Cap de la Circoncision situe a 54 degrees de lat. meridiole et environ a 28 deg. 30 min. de longitude = Plan et gezigt van de landen van de Caap der Besnydenis gelegen op 54 gr. zuider br. en omtrent op 28 gr. 30 min. - Etelaisen pallonpuoliskon halkaisija 44,6 cm
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Kartta kuuluu A. E. Nordenskioldin kokoelmaan
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Kartta kuuluu A. E. Nordenskioldin kokoelmaan
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Kartta kuuluu A. E. Nordenskioldin kokoelmaan
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Kartta kuuluu A. E. Nordenskioldin kokoelmaan
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The renewable energy industry in Zambia is poised for growth and offers many possibilities for Finnish firms willing to enter the market. The Zambian governments deliberate policy measures aim at attracting foreign direct investment (FDI) into this sector. This study rationalises that this could be the pull factor for Finnish firms. The thesis gives an overview of the industry and investigates an appropriate mode of entry, basing its arguments on the comparison analysis of the two economies with the use of the world forums stages of economic development as a framework. The theoretical part of the study examines internationalisation theories, entry mode choice and factors influencing the choice. The multiple case study approach is implored, analysing four case companies from Finland with the use of extant literature on internationalisation relevant to the study. The research design involves the use of documentation, secondary data, interviews and observation. The results of the case analyses show that the Finnish firms most preferred entry mode initially is exporting because it is considered to be less risky. Additionally, the findings also reveal that the selection of a suitable mode of entry is dependent on the firms size, orientation and international experience and could therefore be considered to be subjective. Paramount is the act of gaining market knowledge. The study shows that only hydro-electrical, solar energies and biomass are by far the most used and known forms of renewable energy in Zambia, while other alternative sources still remain un-exploited thus highlighting a growth potential. However, policy formulation and the regulatory framework in the renewable energy sector were found to be wanting.
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Kartta kuuluu A. E. Nordenskioldin kokoelmaan
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Kartta kuuluu A. E. Nordenskioldin kokoelmaan
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Kartta kuuluu A. E. Nordenskioldin kokoelmaan
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Nowadays, the re-refining of the used lube oils has gained worldwide a lot of attention due to the necessity for added environmental protection and increasingly stringent environmental legislation. One of the parameters determining the quality of the produced base oils is the composition of feedstock. Estimation of the chemical composition of the used oil collected from several European locations showed that the hydrocarbon structure of the motor oil is changed insignificantly during its operation and the major part of the changes is accounted for with depleted oil additives. In the lube oil re-refining industry silicon, coming mainly from antifoaming agents, is recognized to be a contaminant generating undesired solid deposits in various locations in the re-refining units. In this thesis, a particular attention was paid to the mechanism of solid product formation during the alkali treatment process of silicon-containing used lube oils. The transformations of a model siloxane, tetramethyldisiloxane (TMDS), were studied in a batch reactor at industrially relevant alkali treatment conditions (low temperature, short reaction time) using different alkali agents. The reaction mechanism involving solid alkali metal silanolates was proposed. The experimental data obtained demonstrated that the solids were dominant products at low temperature and short reaction time. The liquid products in the low temperature reactions were represented mainly by linear siloxanes. The prolongation of reaction time resulted in reduction of solids, whereas both temperature and time increase led to dominance of cyclic products in the reaction mixture. Experiments with the varied reaction time demonstrated that the concentration of cyclic trimer being the dominant in the beginning of the reaction diminished with time, whereas the cyclic tetramer tended to increase. Experiments with lower sodium hydroxide concentration showed the same effect. In addition, a decrease of alkali agent concentration in the initial reaction mixture accelerated TMDS transformation reactions resulting in solely liquid cyclic siloxanes yields. Comparison of sodium and potassium hydroxides applied as an alkali agent demonstrated that potassium hydroxide was more efficient, since the activation energy in KOH presence was almost 2-fold lower than that for sodium hydroxide containing reaction mixture. Application of potassium hydroxide for TMDS transformation at 100 C with 3 hours reaction time resulted in 20 % decrease of solid yields compared to NaOH-containing mixture. Moreover, TMDS transformations in the presence of sodium silanolate applied as an alkali agent led to formation of only liquid products without formation of the undesired solids. On the basis of experimental data and the proposed reaction mechanism, a kinetic model was developed, which provided a satisfactory description of the experimental results. Suitability of the selected siloxane as a relevant model of industrial silicon-containing compounds was verified by investigation of the commercially available antifoam agent in base-catalyzed conditions.
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Bioenergi ses som en viktig del av det nu- och framtida sortimentet av inhemsk energi. Svartlut, bark och skogsavfall tcker mer n en femtedel av den inhemska energianvndningen. Produktionsanlggningar kan fungera ofullstndigt och en mngd gas-, partikelutslpp och tjra produceras samtidigt och kan leda till belggningsbildning och korrosion. Orsaken till dessa problem r ofta obalans i processen: vissa freningar anrikas i processen och superjmviktstillstnd r bildas. I denna doktorsavhandling presenteras en ny berkningsmetod, med vilken man kan beskriva superjmviktstillstndet, de viktigaste kemiska reaktionerna, processens vrmeproduktion och tillstndsstorheter samtidigt. Berkningsmetoden grundar sig p en unik frienergimetod med bivillkor som har utvecklats vid VTT. Den hr s kallade CFE-metoden har tidigare utnyttjats i pappers-, metall- och kemiindustrin. Applikationer fr bioenergi, vilka r demonstrerade i doktorsavhandlingen, r ett nytt anvndingsomrde fr metoden. Studien visade att berkningsmetoden r vl lmpad fr hgtemperaturenergiprocesser. Superjmviktstillstnden kan uppst i dessa processer och det kemiska systemet kan definieras med ngra bivillkor. Typiska tillmpningar r frbrnning av biomassa och svartlut, frgasning av biomassa och uppkomsten av kvveoxider. Ocks olika stt att definiera superjmviktstillstnd presenterades i doktorsavhandlingen: empiriska konstanter, empiriska hastighetsuttryck eller reaktionsmekanismer kan anvndas. Resultaten av doktorsavhandlingen kan utnyttjas i framtiden i processplaneringen och i underskning av nya tekniska lsningar fr frgasning, frbrnningsteknik och biobrnslen. Den presenterade metoden r ett bra alternativ till de traditionella mekanistiska och fenomenmodeller och kombinerar de bsta delarna av bde. --------------------------------------------------------------- Bioenergia on trke osa nykyist ja tulevaa kotimaista energiapalettia. Mustalipe, kuori ja metsthteet kattavat yli viidenneksen kotimaisesta energian kulutuksesta. Tuotantolaitokset eivt kuitenkaan aina toimi tydellisesti ja niiden prosesseissa syntyy erilaisia kaasu- ja hiukkaspstj, tervoja sek prosessilaitteita kuluttavia saostumia ja ruostumista. Usein syy nihin ongelmiin on prosessissa esiintyv eptasapainotila: tietyt yhdisteet rikastuvat prosessissa ja muodostavat supertasapainotiloja. Vitstyss kehitettiin uusi laskentamenetelm, jolla voidaan kuvata nm supertasapainotilat, trkeimmt niihin liittyvt kemialliset reaktiot, prosessin lmmntuotanto ja tilansuureet yht aikaa. Laskentamenetelm perustuu VTT:ll kehitettyyn ainutlaatuiseen rajoitettuun vapaaenergiamenetelmn. Tt niin kutsuttua CFE-menetelm on aiemmin sovelluttu onnistuneesti muun muassa paperi-, metalli- ja kemianteollisuudessa. Vitstyss esitetyt bioenergiasovellukset ovat uusi sovellusalue menetelmlle. Ty osoitti laskentatavan soveltuvan hyvin korkealmpisiin energiatekniikan prosesseihin, joissa kemiallista systeemi rajoittavia tekijit oli rajallinen mr ja siten super-tasapainotila saattoi muodostua prosessin aikana. Tyypillisi sovelluskohteita ovat biomassan ja mustalipen poltto, biomassan kaasutus ja typpioksidipstt. Tyn aikana arvioitiin mys erilaisia tapoja mritell super-tasapainojen muodostumista rajoittavat tekijt. Rajoitukset voitiin tehd teollisiin mittauksiin pohjautuen, kokeellisia malleja hydynten tai mekanistiseen reaktiokinetiikkaan perustuen. Tulevaisuudessa vitstyn tuloksia voidaan hydynt prosessisuunnittelussa ja tutkittaessa uusia teknisi ratkaisuja kaasutus- ja polttotekniikoissa sek biopolttoaineiden tutkimuksessa. Kehitetty menetelm tarjoaa hyvn vaihtoehdon perinteisille mekanistisille ja ilmimalleille yhdisten niden parhaita puolia.
