Gas-liquid mass transfer in bubbly flow: Estimation of mass transfer, bubble size and reactor performance in various applications

Gas-liquid mass transfer is an important issue in the design and operation of many chemical unit operations. Despite its importance, the evaluation of gas-liquid mass transfer is not straightforward due to the complex nature of the phenomena involved. In this thesis gas-liquid mass transfer was evaluated in three different gas-liquid reactors in a traditional way by measuring the volumetric mass transfer coefficient (kLa). The studied reactors were a bubble column with a T-junction two-phase nozzle for gas dispersion, an industrial scale bubble column reactor for the oxidation of tetrahydroanthrahydroquinone and a concurrent downflow structured bed.The main drawback of this approach is that the obtained correlations give only the average volumetric mass transfer coefficient, which is dependent on average conditions. Moreover, the obtained correlations are valid only for the studied geometry and for the chemical system used in the measurements. In principle, a more fundamental approach is to estimate the interfacial area available for mass transfer from bubble size distributions obtained by solution of population balance equations. This approach has been used in this thesis by developing a population balance model for a bubble column together with phenomenological models for bubble breakage and coalescence. The parameters of the bubble breakage rate and coalescence rate models were estimated by comparing the measured and calculated bubble sizes. The coalescence models always have at least one experimental parameter. This is because the bubble coalescence depends on liquid composition in a way which is difficult to evaluate using known physical properties. The coalescence properties of some model solutions were evaluated by measuring the time that a bubble rests at the free liquid-gas interface before coalescing (the so-calledpersistence time or rest time). The measured persistence times range from 10 msup to 15 s depending on the solution. The coalescence was never found to be instantaneous. The bubble oscillates up and down at the interface at least a coupleof times before coalescence takes place. The measured persistence times were compared to coalescence times obtained by parameter fitting using measured bubble size distributions in a bubble column and a bubble column population balance model. For short persistence times, the persistence and coalescence times are in good agreement. For longer persistence times, however, the persistence times are at least an order of magnitude longer than the corresponding coalescence times from parameter fitting. This discrepancy may be attributed to the uncertainties concerning the estimation of energy dissipation rates, collision rates and mechanisms and contact times of the bubbles.

Impact of Investment Strategies on Performance in Pulp and Paper Industry

The main objective of this study was to examine, what kind of investment strategies the leading European and North American pulp and paper industry companies (PPI) used in 1991-2003, and how the selected strategies affected their performance. The investment strategies were categorised in three classes including mergers and acquisitions, investments in new capacity and investments in existing capacity. The results showed that mergers and acquisitions represented the largest share of total investments in 1991-2003 followed by investments in existing capacity. PPI companies changed investment strategies over time by increasing the share of mergers and acquisitions, which decreased investments in new capacity especially among North American companies. According to the results, good asset quality and investments in new and existing capacity provided better profitability than often expensive acquisitions. Also the capacity decreases had a positive impact on profitability. Average asset quality and profitability were higher among European companies. The study concluded that in the long term the available value creating investment opportunities should limit capital expenditure levels, not the relation of capital expenditure to depreciation.

Financial performance of segments in the intelligent home network

The goal of this study is to examine the intelligent home business network in order to determine which part of the network has the best financial abilities to produce new business models and products/services by using financial statement analysis. A group of 377 studied limited companies is divided into four examined segments based on their offering in producing intelligent homes. The segments are customer service providers, system integrators, subsystem suppliers and component suppliers. Eight different key figures are calculated from each of the companies to get a comprehensive view of their financial performances, after which each of the segments is studied statistically to determine the performances of the whole segments. The actual performance differences between the segments are calculated by using the multi-criteria decision analysis method in which the performances of the key figures are graded and each key figure is weighted according to its importance for the goal of the study. The results of this analysis showed that subsystem suppliers have the best financial performance. Second best are system integrators, third are customer service providers and fourth component suppliers. None of the segments were strikingly poor, but even component suppliers were rather reasonable in their performance; so, it can be said that no part of the intelligent home business network has remarkably inadequate financial abilities to develop new business models and products/services.

Role of Capabilities in Purchasing and Supply Management Performance

The objective of this thesis was to study the role of capabilities in purchasing and supply management. For the pre-understanding of the research topic, purchasing and supply management development and the multidimensional, unstructured and complex nature of purchasing and supply management performance was studied in literature review. In addition, a capability-based purchasing and supply management performance framework were researched and structured for the empirical research. Due to the unstructured nature of the research topic, the empirical research is three-pronged in this study including three different research methods: the Delphi method, semi-structured interview, and case research. As a result, the purchasing and supply management capability assessment tool was structured to measure current level of capabilities and impact of capabilities on purchasing and supply management performance. The final results indicate that capabilities are enablers of purchasing and supply management performance, and therefore critical to purchasing and supply performance.

Cooperative strategy in emerging markets - analysis of interfirm r&d cooperation and performance in Russian manufacturing companies

Emerging markets have come to play a significant role in the world, not only due to their strong economic growth but because they have been able to foster an increasing number of innovative high technology oriented firms. However, as the markets continue to change and develop, there remain many companies in emerging markets that struggle with their competitiveness and innovativeness. To improve competitive capabilities, many scholars have come to favor interfirm cooperation, which is perceived to help companies access new knowledge and complementary resources and, by so doing, enables them to catch up quickly with Western competitors. Regardless of numerous attempts by strategic management scholars, the research field remains very fragmented and lacks understanding on how and when interfirm cooperation contributes to firm performance and competiveness in emerging markets. Furthermore, the reasons why interfirm R&D sometimes succeeds but fails at other times frequently remain unidentified. This thesis combines the extant literature on competitive and cooperative strategy, dynamic capabilities, and R&D cooperation while studying interfirm R&D relationships in and between Russian manufacturing companies. Employing primary survey data, the thesis presents numerous novel findings regarding the effect of R&D cooperation and different types of R&D partner on firms’ exploration and exploitation performance. Utilizing a competitive strategy framework enables these effects to be explained in more detail, and especially why interfirm cooperation, regardless of its potential, has had a modest effect on the general competitiveness of emerging market firms. This thesis contributes especially to the strategic management literature and presents a more holistic perspective on the usefulness of cooperative strategy in emerging markets. It provides a framework through which it is possible to assess the potential impacts of different R&D cooperation partners and to clarify the causal relationships between cooperation, performance, and long term competitiveness.

A Study of Multicast Performance in IEEE 802.11 Wireless Local Area Networks

Langattomat lähiverkot ovat yleistyneet ja monin paikoin niillä pyritään täysin korvaamaan perinteiset kaapeloidut verkot. Samalla verkoissa välitettävät palvelut monipuolistuvat. Etenkin interaktiivisten sisältöjen ja viiveriippuvaisten palvelujen välittämisessä korostuvat verkolle asettavat vaatimukset suorituskyvystä ja palveluntasosta. Radiotaajuuksilla tapahtuva tiedonsiirto on ongelmallista siirtomedian jaetun luonteen vuoksi. Käytettäessä ympärisäteileviä antenneja jokainen kantomatkan päässä oleva asema kuulee lähetyksen, vaikkei se olisi sille suunnattu. Tämä luo turvallisuusongelman, mutta lisäksi heikentää tehokkuutta, koska nykyisellä antenniteknologialla vain yksi asema kerrallaan voi lähettää häiriöttä kantoalueellaan. Täsmälähetykset yhden lähteen ja useiden kohteiden välillä luovat erillisiä siirtolinkkejä. Olisi luontevampaa luoda yksi lähetysvirta, johon useat vastaanottajat voivat kytkeytyä. Kaistan säästön vastapainona on tarve luoda ja ylläpitää näitä yhteyksiä. Käyttäjien liikkuvuuden ja siirtotien vaihtelevien ominaisuuksien vuoksi langattoman verkon rakenne ja rajat ovat epäselviä. Näihin haasteisiin on vastattava sekä protokolla- että sovellustasolla. Tässä tutkielmassa käydään ensin läpi IEEE 802.11 -standardin mukaisen langattoman verkon perusteet ja sen ominaisuuksiin liittyvät tyypilliset ongelmakohdat. Yleis- ja ryhmälähetyksiä tarkastellaan ensin perinteisessä IEEE 802.3 standardin mukaisessa langallisessa lähiverkossa ja selvitetään, miten vastaavat ominaisuudet toteutuvat IEEE 802.11 standardien mukaisissa langattomissa verkoissa. Käyttötapaustutkimuksissa keskitytään rajatussa ympäristössä tapahtuviin ryhmälähetyksiin. Erityisesti tutkitaan langattomien ryhmälähetysten käyttökelpoisuutta sekä langattoman ympäristön asettamia erityisvaatimuksia.

Test Anxiety, Coping, Gender and Academic Performance in English Exams: A Study of Finnish Upper Secondary School Students

In this MA thesis, test anxiety related to English exams among Finnish upper secondary school students was studied. In addition, the ways students try to cope with test anxiety were investigated. The purpose of the study was to investigate gender differences in test anxiety, the effects of test anxiety on academic performance and relationships between test anxiety, academic performance and coping strategies. Test anxiety and coping strategies were analysed as scores of questionnaire responses. Coping strategies comprised of three categories – task-orientation and preparation, seeking social support and avoidance. Academic performance was analysed as teacher ratings of general performance in English exams. In total 67 subjects were studied. The subjects were Finnish general upper secondary school students. The data were collected by using online questionnaires. This data were mainly quantitative, but also qualitative elements were included. The quantitative data were analysed by using statistical methods. The results showed that females experienced statistically significantly more test anxiety than males. In addition, a statistically significant correlation was found between test anxiety levels and academic performance ratings of the subjects: the higher the test anxiety score, the lower the academic performance rating. A meaningful correlation was found between test anxiety and seeking social support as a coping strategy: a higher test anxiety score was related to using social support as a coping strategy. However, no relationships were found between academic performance and the three coping strategies when quantitative and qualitative data were analysed. Therefore, different coping strategies per se did not seem to be related to academic performance, but instead it was assumed that the effectiveness of coping strategies is dependent on individual differences. In order to obtain more generalisable results and to gain more understanding of test anxiety and coping with it, a larger number of subjects form different areas of Finland and of different ages could be examined in future studies. Moreover, cross-national and cross-cultural studies could provide valuable information. As a practical recommendation for educational purposes, the results of this study indicated that a more individualised approach is needed.

Temperament and reproductive performance in farmed sable

Selostus: Tarhatun soopelin luonne ja lisääntymiskyky

Evaluation of performance analysis software for Linux computing cluster

Tietokonejärjestelmän osien ja ohjelmistojen suorituskykymittauksista saadaan tietoa,jota voidaan käyttää suorituskyvyn parantamiseen ja laitteistohankintojen päätöksen tukena. Tässä työssä tutustutaan suorituskyvyn mittaamiseen ja mittausohjelmiin eli ns. benchmark-ohjelmistoihin. Työssä etsittiin ja arvioitiin eri tyyppisiä vapaasti saatavilla olevia benchmark-ohjelmia, jotka soveltuvat Linux-laskentaklusterin suorituskyvynanalysointiin. Benchmarkit ryhmiteltiin ja arvioitiin testaamalla niiden ominaisuuksia Linux-klusterissa. Työssä käsitellään myös mittausten tekemisen ja rinnakkaislaskennan haasteita. Benchmarkkeja löytyi moneen tarkoitukseen ja ne osoittautuivat laadultaan ja laajuudeltaan vaihteleviksi. Niitä on myös koottu ohjelmistopaketeiksi, jotta laitteiston suorituskyvystä saisi laajemman kuvan kuin mitä yhdellä ohjelmalla on mahdollista saada. Olennaista on ymmärtää nopeus, jolla dataa saadaan siirretyä prosessorille keskusmuistista, levyjärjestelmistä ja toisista laskentasolmuista. Tyypillinen benchmark-ohjelma sisältää paljon laskentaa tarvitsevan matemaattisen algoritmin, jota käytetään tieteellisissä ohjelmistoissa. Benchmarkista riippuen tulosten ymmärtäminen ja hyödyntäminen voi olla haasteellista.

Value added logistical support service: logistics cost structure and performance in the new concept. Part 3

The aim of this study is to present an Activity-Based Costing spreadsheet tool for analyzing the logistics costs. The tool can be used both by customer-companies and logistics service providers. The study discusses the influence of different activity models on costs. Additionally this paper discusses about the logistical performance across the total supply chain This study is carried out using ananalytical research approach and literature material has been used for supplementing the concerned research approach. Cost structure analysis was based on the theory of activity-based management. This study was outlined to spare part logistics in machine-shop industry. The outlines of logistics services and logisticalperformance discussed in this report are based on the new logistics business concept (LMS-concept), which has been presented earlier in the Valssi-project. Oneof the aims of this study is to increase awareness of different activity modelson logistics costs. The report paints an overall picture about the business environment and requirements for the new logistics concept.

Managing material flows and improving performance in a component supplier’s internal supply chain

Tämä diplomityö tehtiin osana Componenta Cast Componentsin kolmivuotista toimitusketjujen kehitysprojektia. Työn tavoitteena oli kuvata tyypillinen yrityksen sisäinen toimitusketjuprosessi ja tehdä alustava suorituskykyanalyysi valimon ja konepajan väliseen logistiseen prosessiin liittyen. Tarkoituksena oli myös löytää kehityskohteita materiaali- ja tietovirtojen hallinnassa näiden tuotantoyksiköiden välillä. Logistiikkaan, toimitusketjujen hallintaan ja toimitusketjun suorituskyvyn mittaamiseen liittyvän kirjallisuustutkimuksen sekä käytännön perusteella valittiin sopivat analyysimenetelmät. Näitä menetelmiä hyödynnettiin tilaustoimitus – prosessin kuvaamisessa sekä suorituskyvyn analysoinnissa yrityksen sisäisessä toimitusketjussa. Luonnollisena jatkona kehitettiin ja pantiin käytäntöön toimitusketjua synkronoiva imutyyppinen tuotannon- ja materiaalinohjausmenetelmä. Diplomityöprojektin aikana kehitettiin myös apuvälineet käyttöönotetun menetelmän asianmukaista hyödyntämistä varten. Diplomityöprojektissa otettiin ensimmäiset askeleet kohti integroitua sisäistä toimitusketjua. Uuden tuotannon- ja materiaalinohjausmenetelmän standardisointi muihin menetelmiin yhdistettynä, sekä toimitusketjun avainmittarien jatkokehitys on jo alkanut. Läpimenoaikoja lyhentämällä ja synkronoidun, läpinäkyvän kysyntä-tarjontaketjun avulla integroitumisen astetta voidaan nostaa edelleen. Poikkiorganisatorinen kehitys ja johtaminen toimitusketjussa on avainedellytys menestykseen.

Market orientation and performance in entrepreneurial SMEs

Market orientation is the organizational culture that creates the necessary behaviors for continuous additional value for customers and thus continuous superior performance for the business. The field of market orientation has been studied repeatedly during the past two decades. Yet research has concentrated on large firms in large domestic markets creating a need for diversifying research. The master’s thesis at hand examined the general incidence of market orientation among SMEs from five different industries as well as its consequences on SME performance. The empirical part of the thesis was conducted with a web-based survey that resulted in 255 responses. The data of the survey was analyzed by statistical analysis. The incidence of market orientation varied among dimensions and market orientation did not show any direct effect on firm performance. Customer orientation was the only dimension that showed a direct (positive) effect. On the contrary, moderating effects were found which indicate that the effect of market orientation in SMEs is influenced by other factors that should receive further attention. Also industry specific differences were discovered and should be further examined.

The Role of Preannouncing In Innovation Launch Strategy

The objective of this master’s thesis was to examine the role of preannouncing in innovation launch strategy. Preannouncing was studied from three different angles that were preannouncement usage, preannouncement timing and preannouncement goals and from two different perspectives that were the firm’s internal strategy and the external circumstances. The firm’s internal strategy encompassed the product strategy the firm had chosen. The external circumstances consisted of the industry, the nature of competition and the nature of market. Additionally, the product’s performance in the short term was studied in order to be able to speak out whether it is advantageous to preannounce. The empirical study was conducted as a partial replication study. The data for the empirical part was collected with a wide mailing and Internet enquiry in October 2008 – June 2009. Sample (N = 713) consisted of Finnish firms representing different industries and innovation activities. The data collection produced 272 answers and thus, the final response rate of the study was 38.15 %. The data was analyzed by using Microsoft Excel and statistical analysis program SAS Enterprise Guide. As a conclusion, the major results indicate that even if the firms use preannouncing quite often (54.8 % of the respondents), preannouncing behavior cannot be explained by industry. However, out of other external circumstances, the customer related turbulence affects on preannouncing usage. It was also revealed that the product type has an effect on preannouncing behavior. Additionally, preannouncement timing was noticed to differ according to audiences (distributors and end users).

CSR standards and financial performance in forest industry - Empirical analysis

The definition of corporate social responsibility (CSR) has been developed since 1950s but even today there is no consensus what CSR includes. The main purpose of this thesis was to find out whether financial performance is better among first adopters of CSR standards in forest industry. To support the main purpose it was critical also investigate what kind of companies adopt CSR standards. The empirical part of the thesis based on a survey which was done in 2010 to forest industry companies and financial data that was gathered from different databases from years 2003-2010. According to the research results it seems the early CSR standards adopters benefits the position of the first adopter many times. Especially cash position and solvency of early adopter companies were better than later adopters or those who did not adopt CSR standards at all. Profitability seemed to be better among CSR standards adopters but early adopters did not have significantly better position compared to later adopters. CSR standards adopters were companies that considered themselves as environmental performance pioneers and had employee oriented management.