Search results for "sellu"

Progress in Paper Physics Seminar : Abstract book of the PPPS2020 seminar September 1-3, 2020 in Jyväskylä, Finland

2020

The scope of the Progress in Paper Physics Seminar is to discuss the broad scope of physical properties of paper, paperboard and new cellulose containing materialas. The program contain presentations reporting on the latest experimental, theoretical and computational developments. The three invited plenary speakers aim at bringing industry and academia together for in-depth discussions on selected topics in paper physics the potential impact on industry. The selected 37 oral presentations and 12 poster presentations provide opportunity to improve scientific knowledge and explore the latest outcomes and trends in the field. nonPeerReviewed

Aqueous foam as the carrier phase in the deposition of fibre networks

2015

Black Bioinks from Superstructured Carbonized Lignin Particles

2023

A renewable source of carbon black is introduced by the processing of lignin from agro-forestry residues. Lignin side streams are converted into spherical particles by direct aerosolization followed by carbonization. The obtained submicron black carbon is combined with cellulose nanofibers, which act as a binder and rheology modifier, resulting in a new type of colloidal bioink. The bioinks are tested in handwriting and direct ink writing. After consolidation, the black bioinks display total light reflectance (%R) at least three times lower than commercial black inks (reduction from 12 to 4%R). A loading of up to 20% of nanofibers positively affects the cohesion of the dried bioink (1 to 16…

Novel concepts on the recovery of by-products from alkaline pulping

2016

Innovative biorefinery concepts were developed for the separation and utilization of organic materials, especially aliphatic carboxylic acids, lignin, and extractives, which are formed as by-products during wood-based alkaline delignification processes. The partial recovery of sodium as NaOH and aliphatic carboxylic acids from hardwood soda-AQ black liquor was studied via electrodialysis. The lignin was partly (about 59 % of the initial lignin) precipitated from black liquor by carbonation (pH to about 8.5) followed by electrodialysis or H2SO4 (pH to about 2), with subsequent precipitation of more lignin and the liberation of aliphatic acids. The Na2SO4 formed was successfully separated fro…

Cellulose nanofibrils prepared by gentle drying methods reveal the limits of helium ion microscopy imaging

2019

TEMPO-oxidized cellulose nanofibrils (TCNFs) have unique properties, which can be utilised in many application fields from printed electronics to packaging. Visual characterisation of TCNFs has been commonly performed using Scanning Electron Microscopy (SEM). However, a novel imaging technique, Helium Ion Microscopy (HIM), offers benefits over SEM, including higher resolution and the possibility of imaging non-conductive samples uncoated. HIM has not been widely utilized so far, and in this study the capability of HIM for imaging of TCNFs was evaluated. Freeze drying and critical point drying (CPD) techniques were applied to preserve the open fibril structure of the gel-like TCNFs. Both dr…

Differences in parasite susceptibility and costs of resistance between naturally exposed and unexposed host populations

2009

It is generally assumed that resistance to parasitism entails costs. Consequently, hosts evolving in the absence of parasites are predicted to invest less in costly resistance mechanisms than hosts consistently exposed to parasites. This prediction has, however, rarely been tested in natural populations. We studied the susceptibility of three naïve, three parasitized and one recently isolated Asellus aquaticus isopod populations to an acanthocephalan parasite. We found that parasitized populations, with the exception of the isopod population sympatric with the parasite strain used, were less susceptible to the parasite than the naïve populations. Exposed but uninfected (resistant) isopods f…

Säteilyn aiheuttamat värinmuutokset korkeasaantoisessa massassa

2017

Korkeasaantoisen havusulfaattimassan sähkömagneettisen säteilyn aiheuttama kellastuminen aiheutuu puun natiiveista sekä sulfaattikeiton aikana syntyvistä kromoforeista. Kromoforit ovat kemiallisia rakenteita, jotka absorboivat säteilyä näkyvän valon alueelta, minkä seurauksena syntyy värejä. Kellastumisen aiheutumiseksi kemialliseen rakenteeseen on synnyttävä kromoforisia rakenteita, jotka absorboivat näkyvää valoa sini-viher-alueella. Havupuiden osalta kromoforisia rakenteita esiintyy ligniinissä, uuteaineissa sekä hiilihydraattien johdannaisissa. Lopputyöni kirjallisessa osassa perehdytään havupuiden natiivien sekä sulfaattikeiton aikana syntyvien kromoforien ominaisuuksiin sekä muodostum…

Isopoda Asellota de Turquie récoltés en 1987

1996

Asellus aquaticus is present in 19 of about 100 Turkish groundwater stations prospected during biospeleological explorations. All specimens of these stygophilic populations remain oculate, even though their integumental pigmentation is more or less reduced. Proasellus lykaonicus Argano & Pesce, 1978 has been found again in a second cave, nearby the type locality. A large and endemic, stygobiont species, Proasellus pisidicus n. sp., from phreatic groundwater, Vilâyet Burdur, and the minute Proasellus pamphylicus n. sp. from interstitial waters of the eastern part of Vilâyet Antalya are described. The stygobiont proasellids of Asia Minor, P. lykaonicus and P. pisidicus n. sp. belong to the sa…

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…

Conduction properties of thin films from a water soluble carbon nanotube/hemicellulose complex.

2018

We have examined the conductive properties of carbon nanotube based thin films, which were prepared via dispersion in water by non-covalent functionalization of the nanotubes with xylan, a type of hemicellulose. Measurements of low temperature conductivity, Kelvin probe force microscopy, and high frequency (THz) conductivity elucidated the intra-tube and inter-tube charge transport processes in this material. The measurements show excellent conductive properties of the as prepared thin films, with bulk conductivity up to 2000 S cm−1. The transport results demonstrate that the hemicellulose does not seriously interfere with the inter-tube conductance. peerReviewed