Search results for "valmistus"
showing 10 items of 48 documents
On the mechanical stability and out-of-plane dynamics of a travelling panel submerged in axially flowing ideal fluid : a study into paper production …
2011
Stability of Local Out-of-Plane Deformations of Orthotropic Sheet : Numerical Approach
2018
Synthesis, structure and photophysical properties of a highly luminescent terpyridine-diphenylacetylene hybrid fluorophore and its metal complexes
2014
A new fluorescent terpyridyl-diphenylacetylene hybrid fluorophore 4'-[4-{(4-methoxyphenyl)ethynyl}phenyl]-2,2':6',2''-terpyridine, L, was synthesized via Sonogashira cross-coupling of 4'-(4-bromophenyl)-2,2':6',2''-terpyridine and 4-ethynylanisole in the presence of Pd(PPh3)4/CuI as a catalyst. The solid state structure of L shows a trans arrangement of pyridine nitrogen atoms along the interannular bond in the terpyridine domain. Five transition metal complexes of L, {[FeL2](CF3SO3)2 (1), [ZnL2](ClO4)2 (2), [CdL2](ClO4)2 (3), [RuL2](PF6)2 (4), and PtMe3IL (5)}, have also been synthesized and characterized by spectroscopic methods and single crystal X-ray analysis. The X-ray crystal structu…
Synthesis, structure and photophysical properties of a highly luminescent terpyridine-diphenylacetylene hybrid fluorophore and its metal complexes
2015
A new fluorescent terpyridyl-diphenylacetylene hybrid fluorophore 4′-[4-{(4-methoxyphenyl)ethynyl}phenyl]-2,2′:6′,2′′-terpyridine, L, was synthesized via Sonogashira cross-coupling of 4′-(4-bromophenyl)-2,2′:6′,2′′-terpyridine and 4-ethynylanisole in the presence of Pd(PPh3)4/CuI as a catalyst. The solid state structure of L shows a trans arrangement of pyridine nitrogen atoms along the interannular bond in the terpyridine domain. Five transition metal complexes of L, {[FeL2](CF3SO3)2 (1), [ZnL2](ClO4)2 (2), [CdL2](ClO4)2 (3), [RuL2](PF6)2 (4), and PtMe3IL (5)}, have also been synthesized and characterized by spectroscopic methods and single crystal X-ray analysis. The X-ray crystal structu…
Teollisuuden uudet verkostomaiset toimintamallit materiaalitehokkuuden ja kestävän kilpailukyvyn edistäjinä : kehityspolku kohti uusia toimintatapoja
2014
Saostumat kartonkikoneen märkäpäässä sekä kemikaalikierrossa
2016
Työssä perehdyttiin aallotuskartonkia valmistavan Heinolan Flutingtehtaan saostumisongelmien syihin sekä menetelmiin saostumisen estämiseksi. Haihduttamolla saostumat tukkivat haihduttimien tuubilämmönvaihtimet ja rajoittavat haihduttamon toimintaa. Niukkaliukoisten, pääasiassa epäorgaanisten kalsiumsuolojen muodostamien saostumien pesun vuoksi haihduttamo joudutaan seisauttamaan usein, mikä rajoittaa koko tehtaan tuotantoa. Kartonkikoneen märkäpäässä saostumat ovat sen sijaan orgaanisia, pääasiassa puun pihkasta johtuvia, yhdisteitä. Kartonkikoneella saostumista seuraa likakatkoja ja hukkaaikaa. Kirjallisuuden ja aiempien tutkimusten perusteella haihduttamon saostumien syyksi selvisi puust…
Puumateriaalin kemiallinen käyttäytyminen sulfaattikeiton alkalisessa etanoliesikäsittelyssä
2002
Puun alkalisessa kuidutuksessa hiilihydraatit, pääasiassa hemiselluloosat, päätepilkkoutuvat ns. peeling-reaktion mukaisesti, jolloin reaktiotuotteina syntyy ensisijaisesti alifaattisia karboksyylihappoja. Kyseinen reaktio aiheuttaa huomattavia saantotappioita ja heikentää tuotettavan massan laatua. Hiilihydraattiketjun peeling-reaktio voidaan estää muuntamalla ketjun pelkistävä pääteryhmä kemiallisesti esimerkiksi hapettamalla. Tässä tutkimuksessa hiilihydraattien pelkistävän pääteryhmän hapettaminen tehtiin hapella, jonka imeytymistä alkaliseen esikäsittelyliuokseen tehostettiin etanolilisäyksen avulla. Vertailun vuoksi esikäsittelyjä tehtiin myös pelkällä natriumhydroksidillä typpiilmake…
Advanced biorefinery concepts related to non-wood feedstocks
2018
Agricultural residues, such as wheat straw (Triticum aestivum), okra stalk (Abelmoschus esculentus), and giant miscanthus (Miscanthus × giganteus, a hybrid of M. sinensis and M. sacchariflorus) were investigated to assess their possible consumption for integrated lignocellulosic biorefining. The efficient fractionation and recovery of all important chemical components (cellulose, hemicelluloses, and lignin) of such feedstocks are a prerequisite for realistic biorefinery concepts. Water is one of the most eco-friendly solvents with the highest potential for industrial use, and it is also suitable for full-scale biorefinery purposes. For example, under pressure at elevated temperatures over 1…
Chemical Pretreatments of Wood Chips Prior to Alkaline Pulping - A Review of Pretreatment Alternatives, Chemical Aspects of the Resulting Liquors, an…
2015
The chemical industry is being forced to evaluate new strategies for more effective utilization of renewable feedstocks to diminish the use of fossil resources. In this literature review, the integration of both acidic and alkaline pretreatment phases of hardwood and softwood chips with chemical pulping is discussed. Depending on the pretreatment conditions, high-volume sulfur-free fractions with varying chemical compositions can be produced. In case of acidic pretreatments, the major products include carbohydrates (mono-, oligo-, and polysaccharides), whereas under alkaline (i.e., aqueous NaOH) pretreatment conditions, the sulfur-free fractions of aliphatic carboxylic acids, lignin, and ex…
Kitchen chemistry course for chemistry education students: influences on chemistry teaching and teacher education – a multiple case study
2019
AbstractThis study introduces the Kitchen Chemistry (KC) course and its influences on chemistry education as a whole. KC is considered to be a life-relevant learning environment that engages learners in science through the pursuit of personally relevant and meaningful goals. KC, as a form of interdisciplinary learning, aims to develop boundary-crossing skills and to support the development of pupils’ scientific thinking. The purpose of this research was to determine how KC as a context-based teaching approach applies to chemistry education and what it offers to chemistry teaching and teacher education. We found that KC gave lower secondary school pupils the opportunity to understand the che…