In 1991, Corner Brook Pulp and Paper Ltd. reintroduced full-tree systems to their operations, under the assumption that the technology had matured to the point that modern feller-bunchers, skidders and delimbers would be effective in Newfoundland conditions. Preliminary results from the productivity tracking of these machines seemed to confirm this assumption and Corner Brook Pulp and Paper now intend to harvest around 15 to 2O of their timber using this approach.
Nous presentons ici une revue des travaux parus jusqu'a maintenant au sujet du comportement mecanique et de la modelisation des contraintes de sechage dans le bois. Notre presentation est articulee en fonction des principaux domaines - transferts de chaleur et de masse, modeles de contraintes de sechage, proprietes mecaniques du bois lors du sechage et modelisation numerique, l'accent etant mis sur les trois derniers domaines. Afin d'identifier les approches presentant le plus de potentiel pour la description mecanique et la modelisation de contraintes du sechage, notre revue est basee sur une compilation bibliographique d'environ 90 titres.
The main objective of this research is to contribute to the stream of research under way in Canada at the present time on the performance of exterior wall systems. In the process, we will facilitate the continuing and appropriate use of lumber and wood-based panel materials.
Le projet visait la modelisation du positionnement des billes de bois au premier debitage. L'objectif etant de developper de nouvelles methodes de simulation du comportement des appareils et des strategies usuelles de positionnement des billes au premier debitage. Dans un premier temps, une analyse du processus de sciage et des appareils a ete effectuee en rechechant les caracteristiques essentielles a modeliser. Par la suite un ensemble d'algorithmes de nature geometrique a ete developpe de maniere a modeliser les positionneurs existants. Deux methodes de construction des algorithmes ont ete etudiees : la calcul des angles formant une suite de transformations applicables a la representation geometrique initiale des billes et la recherche d'un nouveau referentiel. Cette derniere methode fut examinee en profondeur; son implantation et les resultats generes ont permis de visualiser les effets des differents positionneurs. Les algorithmes resultant du present projet ont d'ailleurs ete integres au prototype du modele de simulation du sciage presentement en developpement au groupe Forintek-Laval.
Red pine coupons treated with chromated copper arsenate (CCA-C), ammoniacal copper arsenate (ACA), modified ammoniacal coper arsenate, ammoniacal copper zinc arsenate (ACZA) and ammoniacal zinc arsenate (AZA) to various retention levels have been in service for 14 years at the West Vancouver marine test site. Similar coupons treated with CCA-C, ACA and creosote have been in service for apporximately 8 years at Shediac Bridge and Whitehead Island, the two marine test sites in New Brunswick. This report summarizes the performance results to date ant attempts to compare relative performances of the various preservatives in Atlantic and Pacific coastal waters.
In developing biocontrol technology against sapstain, Forintek identified ten potential biocontrol fungi, Identification of the metabolites that these leads produce will aid in understandng their mechanisms of biocontrol, facilitate product development, and is essential for regulatory acceptance. Identified as a concern with some of the lead fungi is the possiblity that they may produce mycotoxins of the trichothecene- or gliotoxin-type. ELISA's were developed for the detection of T-2 toxin. T-2 toxin was detected from a known producer, but it was not detected from the lead organisms under the growth conditions tested. Candidates were screened for production of gliotoxin and related metabolites by HPLC and TLC. EL 9 and 10 produced gliotoxin. EL 8 did not produce this mycotoxin, but a structurally-related metabolite. Siderophores have been implicated in resource capture and competition mechanisms of biocontrol. Universal and specific assays for the detection of siderophores was established. Production of hydroxamate-type siderophores was detected for all the leads, EL1 to EL10, when grown in liquid media. Production of siderophores by three staining fungi was also detected. Methods of isolation of siderophores in the iron-free and iron-complex forms and profiling by HPLC methods have been established. The characterization of these materials is continuing
In developing biocontrol technology against sapstain, Forintek identified ten potential biocontrol fungi. Identification of the metabolites that these leads can produce will help in understanding their mechanisms of biocontrol, facilitate product development, and is essential for regulatory acceptance. Identified as a concern with some of the lead fungi is the potential that they may produce mycotoxins of the trichothecene- or gliotoxin-type.
Ce projet constitue le programme d'etude de maitrise d'une etudiante (Annick Tremblay) du departement d'informatique de l'Universite Laval. Les objectifs etaient de developper un algorigthme d'optimisation des operations de delignage et d'eboutage ainsi que de proposer un algorithme effectuant le positionnement optimal des pieces a debiter. L'algorithme choisi pour le delignage et l'eboutage est fonde sur une technique d'optimisation appellee programmation dynamique. Pour sa part, l'algorithme de positionnement fait appel a une technique de subdivision d'intervalles. L'algorithme de positionnement ameliore de 76% le temps de traitement par rapport a l'algorithme de recherche exhaustive (force brute) generalement utilise.
Les travaux prevus pour l'annee fiscale 1993-1994 sont les suivants : 1) Inclure la possibilite de considerer des conditions de sechage variables dans le modele; 2) Inclure la modelisation du transfert de chaleur dans le bois et son couplage avec le transfert de masse; 3) Effectuer une etude de sensibilite afin d'identifier les parametres auxquels le modele est le plus sensible; 4) Determiner la relation teneur en himidite - potentiel hydrique et la conductivite hydrique effective pour l'epinette; 5) Effectuer une etude theorique des phenomenes de transfert convectifs a l'interface bois-air.
Ce rapport renferme essentiellement les specifications fonctionnelles de la version 1.0 du prototype d'un modele de simulation de la transformation des bois en bois de sciage. Une description des structures de donnees, des fonctions et des classes est fournie pour chaque module du prototype. Un listage de l'implantation accompagne egalement chaque module. A la section 2.0, le lecteur peut au depart se familiariser avec les objectifs et l'approche adoptes pour le developpement de ce prototype. A cette fin, un acte de conference et un article scientifique ont ete inseres dans le rapport.
Softwood sawmill designers, engineers and managers may benefit from computer simulation analysis of proposed and existing sawmill systems. Simulation models exist that allow users to construct and execute discrete event simulations, but these have incorporated compromises or limitations that reduce the accuracy of the results, or preclude special considerations and observations. The proposed microcomputer discrete event simulation model will allow for real log shapes, explicit lumber orders, learning curves and catastophe scheduling with emergency actions and transient response analysis.
This paper describes and evaluates new and existing models for exterior log geometry. Compatibility with 1,2,3, and 4-axis shadow scanners determined which models were selected for evaluation. Models were considered for potential use in sawmilling process simulation and optimization. The accuracy evaluation compared models based upon lost and added fiber percentages. All models tended to overestimate log cross section area. Popular circular and elliptical models provided the poorest accuracy. Elliptical models used with 2-axis or 3-axis scanners generated up to 8% lost fiber and up to 15% added fiber. The 3-axis dyadic and Chaikin models provided the best overall performance : lost fiber under 3.5% and added fiber under 13%. Results from the evaluation recommend a 3-axis scanner system for automatic positioning and breakdown optimization. The small benefit obtained from 4-axis models does not justify their use. Other technologies are recommended where better accuracy is needed.
Standard tooth designs for ripsaws carry a cutting edge which is square in relation to the saw blade axis. This saw tooth design proved to be satisfactory in the past when saws were heavy in kerf and sawdust was not considered as an important fibre source for pulp or other fibre based products. Forintek recognized that this tooth design is not optimum for achieving the best sawing performance and producing high quality sawdust for pulp. This report describes the results of extensive sawing experiments carried out in both the laboratory and in the sawmill to develop a new tooth design.
The average relative density of lodgepole pine trees from five sites in three regions of interior B.C. was determined using lumber from a previous joinery-yield study. The use of relative density as a predictor of a site's potential for machine-stress-rated (MSR) lumber was explored by comparing the MSR lumber yields for a high and a low relative density site. There was a significant difference in the average relative density of the sites within a region and between regions. The average relative density ranged from 0.39 to 0.42 with a standard deviation of 0.02 to 0.03. Relative density generally declined with increasing stem height. Logs from the lowest point (first 3.7 meters from stump height of 30 cm) in the stem were higher in relative density than the logs from the upper part of the stem. The yield of 2400f-2.OE MSR grade lumber decreased with decreasing log density. There was a positive and significant correlation between relative density on one hand and stiffness (MOE) and MSR lumber yield on the other. MOE was influenced only partly but significantly by relative density. The overall MSR yield for the high and low relative density sites was significantly different. The site with the higher average relative density gave higher yield of MSR grade 2400f-2.OE and lower rejects (lower than 1650f-1.5E grade), while the site with the lower average relative density produced a negligible amount of the high MSR grade and higher rejects. Trees with high relative density were necessary for producing the 2400f-2.OE grade. Therefore, assessing the average relative density of a site should also quantify the relative density of trees at the upper tail of the relative density distribution.