Search results for "actives"
showing 3 items of 33 documents
Development of fast analysis methods for extractives in papermaking process waters
2011
A fast analysis method with an online sample enrichment technique for the analysis of resin and fatty acids present in papermaking process waters was developed. This method was based on atmospheric pressure chemical ionization (APCI) and mass spectrometry (MS) for the detection of [M-H]- ions of compounds of interest. The method was applied to the control of the most prevalent resin (dehydroabietic and abietic) and fatty (palmitic, stearic, oleic, and linolenic) acid levels in papermaking process waters. Continuous data on these acids are of practical importance when predicting possible deposit-derived problems in the paper machine. The first part of the study was focused on the development…
Durcissement aux radiations de fibres optiques dopées terres rares et d'amplificateurs 'a fibres optiques
2011
National audience; Cette étude vise à comprendre les effets d'une irradiation Ȗ sur les propriétés optiques et structurales des fibres dopées aux Terres Rares en vue de leur utilisation dans des amplificateurs à fibre réalisés pour des applications spatiales. L'enjeu majeur de durcissement de ces composants est abordé via des techniques telles que le chargement en hydrogène et/ou le co-dopage au Cérium du cœur des fibres optiques. L'identification des centres responsables de l'atténuation induite par irradiation et la compréhension des mécanismes de dégradation mis en jeu sont des étapes indispensables au développement de ces fibres.
Behaviour of Extractives in Norway Spruce (Picea abies) Bark during Pile Storage
2022
The current practices regarding the procurement chain of forest industry sidestreams, such as conifer bark, do not always lead to optimal conditions for preserving individual chemical compounds. This study investigates the standard way of storing bark in large piles in an open area. We mainly focus on the degradation of the most essential hydrophilic and hydrophobic extractives and carbohydrates. First, two large 450 m3 piles of bark from Norway spruce (Picea abies) were formed, one of which was covered with snow. The degradation of the bark extractives was monitored for 24 weeks. Samples were taken from the middle, side and top of the pile. Each sample was extracted at 120 °C with both n-h…