The Effect of Dividend Yield to Stocks’ Performance on Bullish and Bearish Finnish Stock Market

This study examines the relationship between dividend yield and stock return over bullish and bearish Finnish stock market by testing for alpha and beta shifts across bull and bear markets. In addition, this study examines if various factors, such as a standard deviation of dividends, firm size and profitability have an effect on the size, of the firms’ dividends and systematic risk of the stocks. We divide stocks into five portfolios on the basis of their past average dividend yields and investigate if the highest yielding portfolios outperform the lowest yielding portfolios during the different market conditions. As a result, high yielding stocks were most stable during the examination period and offered downside protection on bear markets. However, a strategy of forming portfolios with past dividend yields led to negative alphas even in bull markets. Standard deviation of dividends, firm size and profitability were found to have no effect on the size of dividends and systematic risk of the stocks.

Painevesityyppisen ydinvoimalaitoksen sekundääripiirin mallinnus

Tutkimuksen tavoitteena oli kehittää entistä tarkempi ja luotettavampi työkalu Loviisan ydinvoimalaitoksen ensimmäisen reaktoriyksikön sekundääripiirin 50-linjan stationääritilan toiminnan arviointiin. Toisena tavoitteena oli kartoittaa ja raportoida mallintamiseen käytetyn SOLVO-ohjelman kehitysmahdollisuuksia. Tutkimusten perusteella kehitettiin testatusti toimiva prosessimalli, joka dokumentoitiin ja validoitiin yksityiskohtaisesti. Tulevaisuudessa tapahtuvaa kehitystyötä, ja mallin käyttöä varten kehitettiin lisäksi Excel-pohjainen työkalu, jonka avulla SOLVO:n ja Excelin välinen integraatio voidaan myöhemmin julkaistavassa SOLVO:n versiossa viedä nykyistä pidemmälle. Mallintamistyön ohella tutkimuksen aikana selvitettiin olennaisimmat SOLVO:n erityispiirteet ja vahvuudet sekä kartoitettiin sen käyttöön liittyvät kehitystarpeet. Tärkeimpänä kehitysehdotuksena nousi esiin yksittäisissä komponenteissa suoritetun laskennan läpinäkyvyyden parantaminen. Seuraavassa kehitysvaiheessa myös komponenttikohtaiset laskentayhtälöt olisi suositeltavaa asettaa avoimiksi käyttäjäkohtaisille muutoksille. Työn aikana saavutettiin myös muita merkittäviä tuloksia, jotka liittyivät pääosin rinnak-kaisten 10- ja 50-linjojen välisiin yhteyksiin. Linjojen välisiä vaikutuksia analysoitaessa huomattiin niiden olevan olennaisessa asemassa erityisesti sarja-ajon aikana. Mikäli mallilla halutaan kuvata sekä sarja- että rinnanajoa, sen on käsitettävä molemmat linjat ja kaikki niihin liittyvät komponentit. Edellä mainitun lisäksi mallipohjaisen tarkastelun tuloksena tehtiin havaintoja, joiden perusteella nykyistä prosessia voidaan edelleen kehittää. Näistä havainnoista tärkeimpänä merivesipumppujen optimaalisen säätölämpötilan todettiin asettuvan 4,5 – 4,6 °C välille. Toinen huomio liittyi matalapaineturbiinien ulosvirtaushäviöihin, joihin hukataan juoksusta riippuen keskimäärin noin 10 kJ/kg enemmän entalpiaa kuin parhaassa mahdollisessa tapauksessa. Validoinnin yhteydessä havaituista pienistä poikkeamista huolimatta kehitetty malli vastaa hyvin laitokselta saatuja mittaustuloksia sekä muita samassa yhteydessä käytettyjä luotet-tavuuden arviointikriteerejä.

Intensification of hemicellulose hot-water extraction from spruce wood by parameter tuning

The growing population on earth along with diminishing fossil deposits and the climate change debate calls out for a better utilization of renewable, bio-based materials. In a biorefinery perspective, the renewable biomass is converted into many different products such as fuels, chemicals, and materials, quite similar to the petroleum refinery industry. Since forests cover about one third of the land surface on earth, ligno-cellulosic biomass is the most abundant renewable resource available. The natural first step in a biorefinery is separation and isolation of the different compounds the biomass is comprised of. The major components in wood are cellulose, hemicellulose, and lignin, all of which can be made into various end-products. Today, focus normally lies on utilizing only one component, e.g., the cellulose in the Kraft pulping process. It would be highly desirable to utilize all the different compounds, both from an economical and environmental point of view. The separation process should therefore be optimized. Hemicelluloses can partly be extracted with hot-water prior to pulping. Depending in the severity of the extraction, the hemicelluloses are degraded to various degrees. In order to be able to choose from a variety of different end-products, the hemicelluloses should be as intact as possible after the extraction. The main focus of this work has been on preserving the hemicellulose molar mass throughout the extraction at a high yield by actively controlling the extraction pH at the high temperatures used. Since it has not been possible to measure pH during an extraction due to the high temperatures, the extraction pH has remained a “black box”. Therefore, a high-temperature in-line pH measuring system was developed, validated, and tested for hot-water wood extractions. One crucial step in the measurements is calibration, therefore extensive efforts was put on developing a reliable calibration procedure. Initial extractions with wood showed that the actual extraction pH was ~0.35 pH units higher than previously believed. The measuring system was also equipped with a controller connected to a pump. With this addition it was possible to control the extraction to any desired pH set point. When the pH dropped below the set point, the controller started pumping in alkali and by that the desired set point was maintained very accurately. Analyses of the extracted hemicelluloses showed that less hemicelluloses were extracted at higher pH but with a higher molar-mass. Monomer formation could, at a certain pH level, be completely inhibited. Increasing the temperature, but maintaining a specific pH set point, would speed up the extraction without degrading the molar-mass of the hemicelluloses and thereby intensifying the extraction. The diffusion of the dissolved hemicelluloses from the wood particle is a major part of the extraction process. Therefore, a particle size study ranging from 0.5 mm wood particles to industrial size wood chips was conducted to investigate the internal mass transfer of the hemicelluloses. Unsurprisingly, it showed that hemicelluloses were extracted faster from smaller wood particles than larger although it did not seem to have a substantial effect on the average molar mass of the extracted hemicelluloses. However, smaller particle sizes require more energy to manufacture and thus increases the economic cost. Since bark comprises 10 – 15 % of a tree, it is important to also consider it in a biorefinery concept. Spruce inner and outer bark was hot-water extracted separately to investigate the possibility to isolate the bark hemicelluloses. It was showed that the bark hemicelluloses comprised mostly of pectic material and differed considerably from the wood hemicelluloses. The bark hemicelluloses, or pectins, could be extracted at lower temperatures than the wood hemicelluloses. A chemical characterization, done separately on inner and outer bark, showed that inner bark contained over 10 % stilbene glucosides that could be extracted already at 100 °C with aqueous acetone.