Thesis (M.S.)--Oregon State University, 1981. / Typescript (photocopy). Includes bibliographical references (leaves 67-69). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 1977. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 113-114). Also available via the Internet.

Inaug.-diss.--Erlangen. / Lebenslauf. "Quellennachweis": p. 109-111.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1974. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--Oregon State University, 1973. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

A combination of many grades of veneer may be jointly produced by peeling any one type of logs. This means that the plywood manufacturer can not really know the profit margins of the panels he produces. And for most of the manufacturers, the cost of the logs constitutes about 65% of the total cost of producing the plywood panels. Consequently, the manufacturer finds it very difficult to select his sales strategy and to price his panels. The plywood manufacturer also has opportunities to minimize his log cost and processing cost by selecting the right combination of logs to peel and using the right constructions in laying up the panels. Linear programming techniques are used in this study to provide an approach to the above mentioned problems for a selected plywood manufacturer. Through this, it is hoped as well to provide an examination of the way to use linear programming techniques and an evaluation of their usefulness as management tools in plywood manufacturing. A survey of the reported experience of some plywood manufacturers indicated that the use of L. P. had been instrumental in saving some hundreds of thousands of dollars per annum for some manufacturers. An L. P. model was constructed for the largest of the four mills of the Case Company, using the operating situations predicted for the year 1967. Such problems (and their solutions) as were encountered in defining, identifying and measuring the variable process costs and the need for making simplifying assumptions were examined. The L. P. model seeks to optimize the choice of panel output, the choice of log input and the choice of panel constructions simultaneously because these three decisions are interrelated and somewhat interdependent. The L. P. analysis suggests that about 30% of the dollar sales of the Case Mill in 1967 were made in unprofitable (thin) panels. Even after allowing for possible over estimation in measuring the variable processing cost, this may call for a thorough re-examination of the sales strategy and the panel pricing system. To produce the panel output selected for 1967, the best log combination apparently includes the use of a much higher proportion of Fir Peeler #2 and Sawlog #3, Interior Fir and Hemlock-Balsam Mix than was used by the Company in its mill. Also, the model suggests proportions of Fir Peeler #1, #4 and S. F.P. might be much lower than what the Company tended to use. These tentative findings may have significant implications for choosing log acquisition policies. The model suggests the choice in panel construction may be to peel Peeler logs for .104" high quality veneer, Interior Fir for .130" veneer and other low quality logs for .171" core veneer. It also suggests down-grading some veneer and using some subsidiary panel constructions so as to utilize fully the total supply of veneer from the logs peeled. The usefulness of the L.P. analysis is fully realized by making a comprehensive post-optimal analysis of the sensitivity of the optimality of the solution to various changes in the log supply and/or panel demand and/or processing cost situations. This analysis may enable the company to determine which of the operating factors seem crucial in determining the profitability of the panels and what may constitute the best log combination to use. From this, the manufacturer could possibly know when and how to adapt his program of operation in response to any future changes in (or any revision in the forecast of) the operating situation. This analysis is also helpful in gauging the importance of the assumptions made when constructing the model. No comprehensive sensitivity analysis was carried out in this study. However, recommendations regarding appropriate post-optimal analyses are presented. Lastly, the study concludes by presenting an L. P. model of possible use to analyze the four mills of the Company together, recognizing the possibilities of specialization and cooperation among the mills. / Business, Sauder School of / Graduate

Three particle boards, one flake board, one multi-layer board, and a plywood panel, all of 3/8-inch thickness, were overlaid with 1/20-inch Philippine mahogany veneer, using a urea-formaldehyde adhesive. Both non-overlaid and overlaid boards were subjected to physical and mechanical tests involving the glue line and the boards themselves. Results of the glue-line shear test indicated that glue-line failure between the veneer and the boards only occurred in the boards of higher density. Overlaying the boards decreased dimensional change in a plane parallel to the length of the board but slightly increased it parallel to the width of the board. Boards composed of flakes had better strength properties than those composed of particles. No delamination of the board occurred during accelerated aging; however, deterioration in the board core was extensive. In general, overlaying the boards tended to minimize differences in strength properties between boards, and improved the strength properties so as to be almost comparable to those of plywood. Overlaying decreased warping in the boards. Some physical properties of the boards, such as resistance to warping and face-checking, were more satisfactory than those of plywood. / Forestry, Faculty of / Graduate

This work follows successful research by staff members at Forintek Canada Corp. in modifying and extending phenol-formaldehyde (PF) plywood resins with powdered tree foliages and barks. In the present study, two urea-formaldehyde (UF) resins, one commercial and one laboratory synthesized, were modified at 15, 30 and 45% addition levels with finely ground white spruce [Picea glauca (Moench.) Voss] foliage or western hemlock [Tsuga heterophylla (Raf.) Sarg.] bark. Two five-ply Douglas-fir [Pseudotsuga mensiezii (Mirb.) Franco] test plywood panels (38 x 38 cm) were made at 32kg/l00 m² double glueline spread level, six and ten min pressing time at 149°C. The commercial and laboratory synthesized wheat flour extended UF resins were used as controls. Shear strengths and wood failure percentages were recorded for sets of test specimens after conditioning at 22°C and EMC of about 6% (Dry test), one vacuum pressure cycle, five vacuum pressure cycles and boiling cycle. Most formulations with the commercial UF resin containing foliage or bark yielded good bond quality (wood failure and shear strength) similar to the control when tested dry and after one vacuum pressure cycle. Following multi-cycle testing, one formulation containing foliage gave similar wood failure percentage to the control. Two formulations containing bark improved glue bond durability yielding 3 to 12% higher wood failure than the control. Results with the laboratory resin were not as good, showing bond quality lower than with the commercial UF formulation. No formulation survived boiling treatment implying that no modification among those used improved UF resin durability under conditions of high moisture and-temperature. Both UF resins were successfully extended by various foliage and bark additions. It was found that both materials can be used as partial substitutes for the conventional extender wheat flour up to the 40% level. This information may be of use to some developing countries that import wheat to flour-extended UF resins used to bond interior grade plywoods. Such countries could benefit by making use of local tree foliages or barks. / Forestry, Faculty of / Graduate

One factor of wood loss in the manufacture of plywood is implicit in the form of excess thickness in plywood due to the choice of veneer thicknesses and plywood designs used in assembly. The thickness and designs currently in use appear to have come largely from tradition and there is no evidence in the literature to show what constitutes the most economical veneer thicknesses and plywood designs for a mill. The problem of determining them is very complex since many types of plywood are assembled in each mill as some integral multiple combination of a few veneers satisfying the 'balanced design' and other structural specifications. The consumption of logs is dependent on the excess thickness in plywood and the economics of the mill further depend on how efficiently a given set of veneers and designs are used to satisfy the orderfile requirements. In this dissertation, these aspects of the Plywood Design and Manufacturing (PDM) problem are addressed using a mathematical programming approach. The problem of finding the optimal veneer thicknesses, associated plywood designs and product mix is formulated as a non-linear mixed integer mathematical programming model. Utilizing the structure of the constraints and by selecting appropriate variables to branch on, it is demonstrated that the PDM problem can be solved efficiently through an implicit enumeration algorithm involving a tree search procedure. The subproblem to be solved at each feasible node of the tree is a Linear Multiple Choice Knapsack (LMCK) problem whose solution can be obtained explicitly following its coefficient structure. A computer code is written in FORTRAN for the implicit enumeration algorithm. Data obtained from a plywood mill in B.C. is analysed using the PDM model and this code. It is demonstrated that the annual net revenue of the mill can be substantially increased through the use of the PDM model. The PDM model is further extended to mill situations involving more than one species and varying orderfile requirements. The model is reformulated in each case and it is demonstrated that essentially the same tree search procedure can be used to solve all these models. When the orderfile is independent of species, the subproblem to be solved at each node of the tree is a Generalized Network problem. It is shown that this Generalized Network problem can be reduced to a Generalized Transportation problem utilizing the structure of the coefficients and solved as an ordinary Transportation problem. When the orderfile is dependent on species, the subproblem decomposes into several Linear Multiple Choice Knapsack problems. If more than one species of veneer can be mixed within a plywood panel, the subproblem is a linear programming problem. The PDM model is further shown to be a special case of a disjunctive programming problem. Following the development of the PDM model, methods to determine the efficiency of plywood designs and the optimum number of veneer thicknesses for a plywood mill are developed. / Business, Sauder School of / Graduate