Effects of Some Wood Chip Properties on Pulp Quality
A series of TMP experiments were performed at CIPP’s TMP pilot plant, and some pulp properties were measured. By comparing chip and pulp properties, and using projections to latent structures (PLS) analysis, we were able to demonstrate that on-line CMS measurements can be used to predict some pulp properties. It should be pointed out that the focus of this paper is to show how CMS measurements can be used to predict some pulp properties. This prediction will suggest ways to control chip quality so as to ensure pulp quality. We tried to explain some important chip properties included in the measurements, but did not try to model them.
On-line chip analysis : new technology for an improved pulping process
ScanChip est un systeme en ligne d'analyse optique de mesure de la qualite des copeaux base sur leurs dimensions reelles. Les resultats, c'est a dire les differentes granulometries et les distributions en longueur, largeur et epaisseur des copeaux, sont disponibles sous forme numerique ou graphique. Ils peuvent etre visualises a l'ecran, imprimes sous forme de rapports, ou envoyes au systeme de controle existant de l'usine. Le systeme ScanChip fonctionne depuis 1992 dans une usine suedoise de pâte a papier, ou il est installe en aval du lessiveur continu. Cet emplacement permet que le systeme soit utilise pour emettre des alarmes au niveau de la qualite des copeaux, et un controle automatise des melanges de differents stocks de copeaux. D'autres positionnements du systeme permettent de mesurer la qualite des copeaux en sortie de dechiqueteuse ou celles des copeaux en provenance de fournisseurs. Un systeme d'analyse de ce type, qui procure instantanement des donnees sur la qualite des copeaux et achemine les resultats aux operateurs ou aux systemes de controle des procedes, peut aider a definir et controler la qualite des copeaux et les parametres des procedes de fabrication de la pâte et ainsi optimiser la production.
THE BLUE EMISSION FROM CIS‐STILBENES *
Abstract— Under irradiation in glassy solution at 77°K cis‐stilbene shows a broad emission spectrum with a maximum at about 4180 Å. A similar emission is observed from 1,2‐diphenyl‐cyclopentene. The emission is shown to be fluorescence and is shown not to arise from either phenanthrene or the: intermediate (presumed to be a dihydrophenanthrene) involved in the photooxidation of cis‐stilbene to phenanthrene. The observations imply that, at least in a solid matrix, there is a barrier to rotation in the lowest excited singlet. Formation of the cyclic isomer, believed to be a dihydrophenanthrene, occurs on irradiation at room temperature but not at 77°K. Isomerization must provide a path for decay of excited singlets that becomes unavailable at low temperature. The possible general importance of such “chemical” decay mechanisms is discussed.