Synthesis of percarboxylic acids in microreactor

Percarboxylic acids are commonly used as disinfection and bleaching agents in textile, paper, and fine chemical industries. All of these applications are based on the oxidative potential of these compounds. In spite of high interest in these chemicals, they are unstable and explosive chemicals, which increase the risk of synthesis processes and transportation. Therefore, the safety criteria in the production process should be considered. Microreactors represent a technology that efficiently utilizes safety advantages resulting from small scale. Therefore, microreactor technology was used in the synthesis of peracetic acid and performic acid. These percarboxylic acids were produced at different temperatures, residence times and catalyst i.e. sulfuric acid concentrations. Both synthesis reactions seemed to be rather fast because with performic acid equilibrium was reached in 4 min at 313 K and with peracetic acid in 10 min at 343 K. In addition, the experimental results were used to study the kinetics of the formation of performic acid and peracetic acid. The advantages of the microreactors in this study were the efficient temperature control even in very exothermic reaction and good mixing due to the short diffusion distances. Therefore, reaction rates were determined with high accuracy. Three different models were considered in order to estimate the kinetic parameters such as reaction rate constants and activation energies. From these three models, the laminar flow model with radial velocity distribution gave most precise parameters. However, sulfuric acid creates many drawbacks in this synthesis process. Therefore, a ´´greener´´ way to use heterogeneous catalyst in the synthesis of performic acid in microreactor was studied. The cation exchange resin, Dowex 50 Wx8, presented very high activity and a long life time in this reaction. In the presence of this catalyst, the equilibrium was reached in 120 second at 313 K which indicates a rather fast reaction. In addition, the safety advantages of microreactors were investigated in this study. Four different conventional methods were used. Production of peracetic acid was used as a test case, and the safety of one conventional batch process was compared with an on-site continuous microprocess. It was found that the conventional methods for the analysis of process safety might not be reliable and adequate for radically novel technology, such as microreactors. This is understandable because the conventional methods are partly based on experience, which is very limited in connection with totally novel technology. Therefore, one checklist-based method was developed to study the safety of intensified and novel processes at the early stage of process development. The checklist was formulated using the concept of layers of protection for a chemical process. The traditional and three intensified processes of hydrogen peroxide synthesis were selected as test cases. With these real cases, it was shown that several positive and negative effects on safety can be detected in process intensification. The general claim that safety is always improved by process intensification was questioned.

Mellom tradisjon og spel : didaktikk for tekstil folkekunst

Denne avhandlinga er resultatet av eit behov for å forske på og utvikle ein didaktikk for tekstilfaget ved Folkekunststudiet, Institutt for folkekultur, Høgskolen i Telemark, Noreg. Studiet med folkekunst som fagfelt er eit relativt ungt studium på høgskolen, som vart etablert i 1984. Problemstillinga i denne avhandlinga er korleis ein kan utvikle ein forskingsbasert didaktikk der dei grunnleggjande prinsippa som særmerkjer den tradisjonelle folkekunsten, vert tekne vare på. I arbeidet med avhandlinga har eg prøvd på å klårgjere problemstillinga ut frå ulike perspektiv. Forskingsarbeidet har fokus på kommunikasjon og arbeidsmåtar i ljos av ulike teoriar. Det er ei hermeneutisk tilnærming som er vald for den didaktiske forståinga. Det fyrste drøftingstemaet har søkjeljos på kommunikasjon og dialog ved vidareføring av tekstil folkekunst. Både estetiske, teoretiske, praktiske og sosiale aspekt er nedfelte i læreplanen for studiet og skal utgjere grunnlaget for kommunikasjon og arbeidsmåtar. I den skapande og kopierande prosessen er det utvikla språklege reiskapar for både den sosiale og den estetiske sida der den teoretiske og praktiske faktoren er integrert. Møte med døme på tekstile tradisjonar så vel som praktisk forming av tekstilar har ført til refleksjon og dialog som involverer kontemplasjon, korrespondens og imaginasjon. Det andre temaet som er drøfta, er vidareføring av tradisjonelt visuelt formspråk. Her er merksemda retta mot kva som har skjedd formalt med ei gruppe tradisjonelle formelement i tekstilar i den institusjonelle vidareføringa over eit lengre tidsperspektiv. Resultatet syner at mange tradisjonelle formelement er borte frå den institusjonelle produksjonen. Formelementa kan ha fått ei meir naturalistisk utforming, eller dei er overførte til andre tradisjonelle tekstilteknikkar enn dei som var utgangspunktet. Rombeforma i den institusjonelle produksjonen er utført i færre variasjonar og kombinasjonar enn i den tradisjonelle produksjonen. Konklusjonen på drøftingstemaet er at spelereglar og spatialitet i høve til den formale komponenten i utvalet med tradisjonelle tekstilar ikkje er vidareført i alle gruppene av institusjonelle produkt. Resultatet kan få innverknad og fylgjer for utforming av ein framtidig didaktikk for faget. Arbeidsmåte og erfaring frå vidareføring av tekstile tradisjonar er det tredje temaet som er drøfta i avhandlinga. Kopiering og skapande prosessar er arbeidsmåtar som er brukte ved studiet i dag, og dei utgjer grunnlag for drøftingar i relasjon til vidareføring og erfaring. Konklusjonen er at i den skapande prosessen korrigerer tradisjonen utforminga, medan i kopiprosessen er eigen stilvilje og improvisering resultat av prosessane. Personar som deltek i prosessane, har sett seg sjølve og si historiske forankring inn i spelet, der visuelt og verbalt språk er resultat av integrasjon av tradisjonar. Dei tre drøftingstemaa utgjer grunnlaget for at didaktikk for folkekunst og tekstil kan bli intersubjektiv forståing av kva ein didaktikk for vidareføring av folkekunst med vekt på tekstil kan vere i utdanninga i dag. Indre og ytre dialog i skapande og kopierande prosessar femner om estetiske, materielle og tekniske faktorar sett i høve til spelereglar, spelerom, spatialitet og samspel i møte med tekstile tradisjonar. Samla utgjer det ein forskingsbasert didaktikk for faget der den overordna intensjonen er samtykke mellom tradisjon og spel.

Jeg strikker, derfor er jeg! : læring og identitet i uformelle læringsrum

The dissertation ´I knit, therefore I am!´ Learning and identity in informal space has two main purposes. The first purpose being an investigation of how new value attributions and thinking can generate novel and usable knowledge to the field of craftsmanship, and the second purpose being a display of a different and overlooked philosophical and cultural potential in a reflexive mode of expression, which is able to reflect the normative comprehension of craftsmanship. The dissertation focuses on learning and identity in informal spaces of learning and how it is possible to relate such a learning perspective to crafts training in educational establishments. The empirical foundation of this dissertation is ‘craftivism’. In the dissertation activists from the Nordic countries have been interviewed about what they do when they put up their textile graffiti on lamp posts and house walls. Three research problems are presented: 1) What stories do people who work as crafts activists, tell about ways of relating and methods of action when they make crafts? 2) What do these stories tell about learning and identity? 3) How may the research results influence training and education in craftsmanship? These questions are being asked in order to acquire new knowledge in two aspects; first aspect being knowledge about crafts in relation to techniques, tradition and the objects in crafts, and the second aspect being knowledge about learning and identity in informal spaces of learning. The dissertations theoretical foundation is post structural and sociocultural combined with hermeneutical-inspired qualitative interviews. The author’s position and pre-understanding is subject to discussion in relation to the informant; the performing activist, as the background for both of them is craftsmanship. Starting from cultural studies, it is possible to see the activist subject’s conditions of possibilities in the culture, as the activism of the sub-cultural phenomenon’s craft lights up through a performing approach to the individual’s actions. First the research material has been analysed for events of textile graffiti and possible themes in the events, after which the results have been summarised. Next the research material has been analysed for events about learning and identity due to the author’s wish of comprehending the background of and motivational force in activism. The analysis is divided in main perspectives with different dimensions. The results of the analysis show the activist subject’s construction of an individual who actively takes part in a community by e.g. creating joy, changing the world’s perception of sustainability or by feminizing the public space. By taking crafts over the borders (and away from the class room) crafts become contextualized in a novel fashion thus obtaining an independent status. In this fashion the dissertation writes itself into a new method of comprehending and performing traditional craftsmanship techniques.

Toimittajan valinta tekstiili- ja vaateteollisuudessa

Kandidaatintutkielma tutkii toimittajan valintaa tekstiili- ja vaateteollisuudessa. Tutkielman fokus onnistuneessa toimittajan valinnassa ja siihen liittyvissä tekijöissä.

Ohuiden päällystyskerrosten applikointi puukuitupohjaisille materiaaleille

Työn aiheena oli tutkia vaahdon soveltuvuutta ohuiden päällystyskerrosten applikointiin paperin tai kartongin pinnalle. Paperia ja kartonkia päällystetään teollisessa mittakaavassa eri menetelmillä, mutta niille kaikille yhteistä on päällystyspastan laimentaminen vedellä ennen applikointia ja laimennusveden haihduttaminen applikoinnin jälkeen päällysteen asettamiseksi. Laimennus on tärkeää pastan komponenttien tasaisen levittämisen vuoksi, mutta veden haihduttaminen kuluttaa valtavasti energiaa. Tekstiiliteollisuudessa on saavutettu merkittäviä säästöjä kuivausenergiassa korvaamalla laajalti vedellä laimentaminen vaahdottamisella. Diplomityön kirjallisessa osassa käytiin läpi vaahdon kemiallisia ja fysikaalisia ominaisuuksia sekä selvitettiin mitä kemikaaleja ja laitteita vaahdotukseen käytetään. Lisäksi luotiin katsaus vaahtoprosessien käyttöön tekstiiliteollisuudessa ja muilla aloilla. Kokeellinen osa koostui esikokeista, joissa selvitettiin pastan koostumuksen vaikutuksia vaahtoamiseen, ja pilot-mittakaavan koeajoista, joissa esikokeiden tuloksia hyödynnettiin. Esikokeissa huomiota kiinnitettiin varsinkin eri polyvinyylialkoholien (PVA) seosten erinomaiseen vaahtoavuuteen. Pilot-koeajoissa vaahtopäällystys vaikutti lupaavalta menetelmältä, joskaan täysin tyydyttävää päällystystulosta ei saavutettu. Suurimpana ongelmana esiintyi ilman pääseminen pohjapaperin ja päällysteen väliin ja siitä seuraava huono päällystejälki. Toisen ongelmakokonaisuuden muodostivat päällysteeseen jäävät reiät. Vaahtopäällystys vaikuttaa lupaavalta tekniikalta ohuiden päällystekerrosten applikointiin, mutta pastareseptejä tulee optimoida ja ratkaista päällysteen alle pääsevän ilman ongelma.

Stability and properties of cellulose-sodium hydroxide solution systems

Since cellulose is a linear macromolecule it can be used as a material for regenerated cellulose fiber products e.g. in textile fibers or film manufacturing. Cellulose is not thermoformable, thus the manufacturing of these regenerated fibers is mainly possible through dissolution processes preceding the regeneration process. However, the dissolution of cellulose in common solvents is hindered due to inter- and intra-molecular hydrogen bonds in the cellulose chains, and relatively high crystallinity. Interestingly at subzero temperatures relatively dilute sodium hydroxide solutions can be used to dissolve cellulose to a certain extent. The objective of this work was to investigate the possible factors that govern the solubility of cellulose in aqueous NaOH and the solution stability. Cellulose-NaOH solutions have the tendency to form a gel over time and at elevated temperature, which creates challenges for further processing. The main target of this work was to achieve high solubility of cellulose in aqueous NaOH without excessively compromising the solution stability. In the literature survey an overview of the cellulose dissolution is given and possible factors contributing to the solubility and solution properties of cellulose in aqueous NaOH are reviewed. Furthermore, the concept of solution rheology is discussed. In the experimental part the focus was on the characterization of the used materials and properties of the prepared solutions mainly concentrating on cellulose solubility and solution stability.

SME internationalisation from an emerging market to a developed market : a case study from Ghana

This study focuses on understanding the internationalisation of small and medium-sized enterprises (SMEs) from an emerging market to a developed market. In particular, it examines the internationalisation process of a firm in the clothing and textile manufacturing industry in Ghana. Theoretically, the study is limited to the network internationalisation approach (e.g. Johanson & Mattsson, 1988; Johanson & Vahlne, 2009) and the industrial network approach (Håkansson & Snehota, 1995). Methodologically, a qualitative abductive case study approach is employed. The research process relies on a longitudinal method involving primary and secondary data and critical event analysis. Primary data has been collected from relevant informants at two different times in the internationalisation process. The research findings highlight the significance of both domestic and foreign business relationships in the internationalisation of an SME from an emerging African market to a developed country market. They show the greater importance of exogenous critical events than has been found in the research regarding firms in developed countries. Institutional actors were essential in the network and as sources of exogenous critical events. In addition, the successful SME should possess unique resources in the form of an entrepreneurial spirit, sufficient knowledge of internationalisation, and specific product knowledge. Theoretically, the present study contributes to business network research through providing an understanding of the process of developing network relationships and their impact in an African context. By focusing on SMEs, a contribution has been made in relation to the advancement of SME research. This research reveals empirical insight into SME internationalisation in a setting where an SME is internationalising to a developed country market from a newly emerging African market. Methodologically, the study provides an example of longitudinal research based on abductive methodology. The results provide implications for firms, managers, and policy-makers within the industry, especially on how to manage and use network relationships to promote SME internationalisation from newly emerging markets.

Jätevesien puhdistus jätevesialtaissa jäädyttämällä - Kartoitus potentiaalisista sovellutuksista Suomessa

Uusia jäteveden puhdistusprosesseja kartoitetaan Suomessakin esimerkiksi kiristyvien päästömääräyksien vuoksi sekä parempia kustannus- ja energiatehokkuuksia tavoiteltaessa. Jätevesien puhdistus on Suomessa jo nykyään hyvällä tasolla, mutta muun muassa raskasmetallien, torjunta-aineiden, hormonien ja lääkeaineiden pitoisuuksien kasvut jätevesissä asettavat haasteita nykyisin käytössä oleville jäteveden puhdistusmenetelmille, sillä niitä ei ole suunniteltu näiden aineiden talteenottoon ja suurin osa aineista jää veteen. Lisäksi jätevedet halutaan nähdä enemmänkin resurssina kuin jätteenä, josta voidaan ottaa talteen hyödyllisiä komponentteja, kuten suoloja. Alueilla, joissa vuorokauden keskilämpötila pysyttelee edes osan vuodesta pakkasella, veden luonnollista jäätymisprosessia voidaan käyttää hyväksi jäteveden puhdistuksessa. Tässä työssä selvitettiin kiteytymisen teorian ja aikaisempien tutkimusten avulla, millaisten jätevesien puhdistukseen jäädytyskiteytys sopii sekä pohdittiin menetelmän potentiaalisia sovelluskohteita Suomessa. Jäädytyskiteytyksen todettiin olevan turvallinen ja energiatehokas ratkaisu monien koostumukseltaan erilaisien jätevesien puhdistukseen. Menetelmällä voitaneen puhdistaa öljyisiä, orgaanisia ja/tai epäorgaanisia epäpuhtauksia tai raskasmetalleja sisältäviä sekä myrkyllisiä jätevesiä. Olosuhteet prosessille ovat parhaat Pohjois-Suomessa, jossa vuorokauden keskilämpötila pysyttelee nollan alapuolella noin seitsemän kuukautta vuodesta. Etelä-Suomessa vastaava luku on kolme. Menetelmän potentiaalisia sovelluskohteita ovat esimerkiksi kaivosteollisuuden ja kaatopaikkojen jätevedet, joiden puhdistukseen jäädytyskiteytys saattaisi soveltua erinomaisesti. Jäädyttämällä voitaisiin myös puhdistaa tekstiili- ja nahkateollisuuden jätevesiä, sillä niiden sisältämien väriaineiden erottaminen vedestä on perinteisillä jäteveden puhdistusmenetelmillä usein vaikeaa tai jopa mahdotonta. Suolojen kiteyttämiseen vaadittavia korkeampia suolapitoisuuksia todettiin löytyvän lähinnä membraaniprosessien, kuten käänteisosmoosin, rejektivesistä. Sopivimmat eutektiset olosuhteet kiteyttämiseen ovat natriumsulfaatilla, kaliumsulfaatilla ja natriumkarbonaatilla. Veden luonnollisen jäätymisprosessin hyödyntäminen jätevedenpuhdistuksessa on huomionarvoinen idea. Prosessin käyttöönottoa haittaavat esimerkiksi korkeat investointikustannukset, mutta ne tulevat todennäköisesti ajan myötä teknologian kehittyessä laskemaan. Lisäksi monet prosessiin liittyvät käytännön asiat ovat vielä tutkimuksen alla. On myös huomattava, että Suomessakaan lämpötila ei pysyttele koko vuotta pakkasella, joten jäädytyksen rinnalla on oltava jokin toinen prosessi, jolla jätevedet puhdistetaan lämpötilan ollessa nollan yläpuolella.