The objective of the research is to reduce the volatile organic compounds (VOCs) emitted during kiln drying of southern yellow pine (SYP) lumber. Three treatment methods were explored to determine their effect on VOC emissions. The three methods were configured at the air exhaust of a pilot-scale dry kiln. 1) A steel reactor containing copper tubing heated to 100°, 200°, and 240° Celsius was evaluated. Temperature did not statistically affect VOC emissions (p-value = 0.1674). The average reduction of VOCs at 240° C was seven percent. 2) The use of hydrogen peroxide and ultra-violet (UV) light did not reduce VOCs emitted during kiln drying. 3) The use of Fenton?s reagent, with hydrogen peroxide and ferrous sulfate, also did not reduce VOCs emitted during kiln drying. 4) It is recommended that future studies with copper heated to temperatures above 240° C be performed.

Knowing and understanding the sapwood and heartwood functions and properties are crucial in pressure-treating southern pine. It is very difficult to penetrate heartwood with chemicals. Therefore, knowing heartwood content before treatment will benefit companies in chemical consumption, treating cycles, and, foremost, cost. In this study, two different assessments were conducted in which lumber and pole heartwood/sapwood data was collected from eight treating plants across five Southeastern states. In both assessments, the data indicated some significant differences between similar products from different vendors, but there was no significant difference in heartwood content between plant locations. The results suggested that the amount of heartwood increases as the size and length of the products increase. These findings can argue that the size of raw materials that vendors use and the products they manufacture have more effect on heartwood content than plant location.

The processing of southern yellow pine (Pinus spp.) (SYP) trees into dimensional lumber is a multi-billion dollar industry in the Southeast United States. The finished product is subject to a classic strength assessment procedure known as visual grading. In this study, 484 specimens of No.2 2 inch by 8 inch (nominal) SYP dimensional lumber were visually assessed for strength reducing defects, visually graded by a certified lumber grader, and destructively tested. Destructive testing was performed in accordance with ASTM D4761-13 for modulus of rupture (MOR) and modulus of elasticity (MOE). These results were used to identify parameters which could be significant when developing a potential working stress-class system to improve the efficiency and yield of the specified grade. Six specific visual characteristics were identified that could predict a superior quality product when compared to the current strength and stiffness properties of No.2 2 by 8 lumber.

Finding alternative uses for small diameter raw materials is a critical problem throughout the United States. Insufficient markets for small diameter, southern yellow pine (Pinus spp.) trees from first plantation thinnings are impacting silvicultural practices on millions of acres of land. In western states, the lack of markets for small diameter ponderosa pine (Pinus ponderosa) and lodgepole pine (Pinus contorta) creates multiple problems in terms of excess material in the forest. This excess material enhances fire potential and reduces land management practices. This research deals with a new structural composite from small diameter raw logs using a technology called steampressed scrim lumber (SPSL). Mechanical and physical properties were performed and evaluated for each species. This research was conducted to evaluate these properties and to determine the suitability for commercialization.

The feasibility of using modified nano-chitosan particles as an environmentally friendly wood preservative agent was investigated in this research. Chitosan nano-particles were prepared from commercially available low molecular weight (LMW) chitosan and its derivative, trimethyl chitosan (TMC). The specific amount of sodium nitrite added to LMW chitosan through depolymerization process indicated the desired chitosan oligomers. Thin layer chromatography (TLC) was done to confirm the formation of chitosan oligomers with degree of polymerization four. Preparation of TMC was done through a quaternization process and Fourier-transform infrared spectroscopy (FTIR) graphs proved the formation of TMC. Sodium tri-poly phosphate (TPP) as a commercial fire retardant was added to these nanoparticles (chitosan oligomers and TMC) to form nanochitosan-TPP particles based on the ionic gelation method. The viscosity of chitosan nanoparticles which were made by chitosan oligomers and TMC were measured by rheometer. The results showed very low viscosity in comparison to LMW chitosan. The final concentration of chitosan oligomers, TMC and TPP in the nano-chitosan-TPP solution to treat wood were 12, 12 and 4.8% respectively. Then, these particles were used to treat southern yellow pine wood through vacuum impregnation process. Mass and volume of samples increased after treatment which means the nano-chitosan-TPP particles penetrated into cell walls. To study the leaching of treated samples, they were soaked to water according to the E11 standard test (AWPA, 2016) and to investigate the fungi resistance of treated samples, they were exposed to brown rot fungus (Gloeophyllum trabeum) and white rot fungus (Trametes versicolor) according to the E10 standard test (AWPA, 2016). Mass loss of the samples was compared to untreated wood controls. The results of leaching and fungi indicated that non quaternized nanochitosan-TPP particles were more effective than quaternized nanochitosan-TPP particles. Measuring the fire resistance and water vapor sorption isotherm of treated samples revealed that there were not any differences among treated and control samples.

Recently, capital investment amounts into Mississippi’s forest products industry have been disproportionate compared with those in neighboring states. Reasons for this have been casually hypothesized, but the topic has not been researched in depth. An economic model has been developed that will aid stakeholders in examining and addressing this issue. The model utilizes county-level data related to southern yellow pine (SYP) lumber manufacturing in tandem with a linear programming solver to produce estimates of annual costs for a SYP sawmill built in any southeastern county. Early results suggest that Mississippi has been an underutilized location for investments in SYP lumber manufacturing based on the costs estimated by the model. The model will be exceptionally useful to those involved in forest industry recruitment efforts because it provides an objective method by which sites in Mississippi can be evaluated for suitability in contrast with sites in neighboring states.

The objectives of this research were twofold: a) to define the relationship between tooth withdrawal and specific gravity for southern pine lumber and four different plate-to-wood load orientations, and b) to demonstrate how these relationships could be applied to new lumber grades to predict tooth withdrawal performance so that additional testing would not be necessary. The four orientations investigated were: a.) LRAA - plate axis parallel to load and wood grain parallel to load. b.) LREA - plate axis perpendicular to load and wood grain parallel to load. c.) LRAE - plate axis parallel to load and wood grain perpendicular to load. d.) LREE - plate axis perpendicular to load and wood grain perpendicular to load. For the LRAA, LREA, LRAE, LREE orientations, the following sample sizes were respectively: 27, 22, 27, and 29. Results showed specific gravity and embedment gap were excellent predictors of ultimate tooth withdrawal stress for the LRAA orientation. However, neither specific gravity nor percentage of latewood significantly influenced the location of tooth withdrawal. For the LREA orientation, specific gravity alone was a good predictor of ultimate tooth withdrawal stress. Furthermore, the side of the joint test specimen where tooth withdrawal initiated was dependent on the wood piece with the lowest mean specific gravity. For the LRAE orientation, specific gravity was a marginal predictor of ultimate tooth withdrawal stress. For the LREE orientation, specific gravity was a decent predictor of ultimate tooth-withdrawal stress. / Master of Science

Knots are usually regarded as defects when grading lumber. In order to evaluate a member under out-of-plane loading, shear strength is one of the major mechanical properties, specifically, rolling shear (RS) strength is one of the critical mechanical properties of Cross-Laminated Timber (CLT), which determines the flexural strength of CLT under short-span bending loads. Lower grade lumber with a higher percentage of knots is recommended to be utilized for the cross-layer laminations which are mainly responsible for resisting shear stresses. Firstly, shear tests were performed in order to evaluate the effect of knots on longitudinal shear strength using shear blocks. After that, the effect of knots on the RS strength of 3-ply southern yellow pine CLT were investigated by experimental tests and an analytical model. Center-point bending tests with a span-to-depth ratio of 6 and two-plate shear tests with a loading angle of 14° were conducted on six CLT configurations composed of different types of cross layer laminations: clear flatsawn lumber with/without pith, lumber with sound knots with/without pith, and lumber with decayed knots with/without pith. The shear analogy method was implemented to evaluate the RS strength values from the bending test results, which were also compared against the results from the two-plate shear tests. It was found that: (1) The shear blocks containing sound knots had higher shear strength than matched clear shear blocks, the shear blocks containing unsound knots had lower shear strength than the matched clear shear blocks. (2) CLT specimens with cross-layer laminations with either sound knots or decayed knots had higher RS strength. (3) In general, the shear analogy method underestimated the RS strength of CLT specimens containing knots and pith.

The purpose of this research was to quantify properties of strandboard panels manufactured with various preservatives at loading levels effective against native termites. Panels were manufactured using nine different formulations. The method of preservative addition was also examined for some preservative formulations, increasing the total number of preservative treatments to twelve. Panels were manufactured with one target retention for each preservative treatment. An effective preservative loading relative to termites was established by previous studies or referencing current standards. Mechanical testing performed included static bending and internal bond. Physical testing included water absorption, thickness swell, and linear expansion. Few treatments met the Canadian standards for strandboard, but several preservatives performed well. Copper naphthenate, bifenthrin, and copper betaine each deserve further investigation to optimize manufacturing variables to meet required mechanical and physical properties.

[EN] Historical study of timber in the architecture of Valencia. Preliminary analysis for the conservation: identification of wood, constructive analysis, assessment, classification and dendrochronology With regards to the historic timber structures, the historical research, the typological and constructive analysis, the structural classification and assessment done on-site are the basis of their conservation. The text of this dissertation focuses on timber structures in the city of Valencia, including some examples of the Valencian Community. The research is structured into three parts whose common thread is the endorsement of the conservation of historic wooden structures. The first part focuses on the management done by the Carpenters' Guild and on the matters of the local transport of wood, as well as its import from the United States, trying to draw the geographic origin of the material used in the historical structures of Valencia. The second part focuses on the typological and constructive study of the floor and roof's structures that can be currently found in Valencia. After a first approach to the places, a systematic analysis of the floors and roofs is done through a classification that finally synthesizes the information collected in order to define the characteristics of the different types and morphologies of the architectural elements that characterize those structures, showing the richness also in the simplest and most widespread morphologies. In parallel with this typological synthesis a statistical analysis of the dimensional data is performed in order to further specify the characteristics of the components. The last part focuses on practical aspects of timber structures' analysis necessary to carry out any knowledgeable restoration project. As this part is applicable to different realities, the analyzed buildings are located not only in the historical center of Valencia, but also in the Valencian Community. Among these studies there is, firstly, the assessment of the structures and then, once identified and understood the types and causes of degradation, the process continues with the classification of the structures in order to estimate their mechanical characteristics. The text ends with the use of the dendrochronological analysis for the dating of wooden structures. / [ES] Estudio histórico de la madera arquitectónica en la ciudad de Valencia. Análisis previos para la conservación y puesta en valor: identificación de maderas, análisis constructivo, diagnóstico, clasificación y dendrocronología En lo que a las estructuras históricas de madera se refiere, la investigación histórica, el análisis tipológico y constructivo, la clasificación estructural in situ y el diagnóstico son la base de su conservación. La investigación estructurada en el texto de la presente tesis doctoral se centra en estructuras de madera de forjados y cubiertas de la ciudad de Valencia intramuros, ampliándose con algunos ejemplos de la Comunidad Valenciana. La investigación se ha estructurado en tres partes cuyo hilo conductor es la promoción de la conservación de las estructuras históricas de madera. La primera parte se concentra en la gestión del gremio de carpinteros y en las cuestiones del transporte local de la madera, así como su importación desde Estados Unidos, tratando de dibujar la geografía de la procedencia del material empleado en las estructuras históricas de Valencia. La segunda parte versa sobre el estudio constructivo y tipológico de los forjados y cubiertas que actualmente se pueden encontrar en la Valencia intramuros. Tras un acercamiento a los lugares y una toma de conciencia de las problemáticas y dificultades inherentes, se realiza un análisis sistemático de los ejemplos de forjados y cubiertas a través de una catalogación en fichas, sintetizando finalmente toda la información recogida para llegar a delinear las características de los diferentes tipos y morfologías de elementos arquitectónicos que caracterizan dichas estructuras, mostrando así la riqueza de detalle existente también en las morfologías más simples y difundidas. Paralelamente a esta síntesis tipológica se realiza también un análisis estadístico de los datos dimensionales para puntualizar aún más las características de los elementos constitutivos. La última parte se concentra en aspectos prácticos de los análisis de las estructuras de madera necesarios para llevar a cabo cualquier proyecto de restauración bien informado. Tratándose de una sección más propositiva y aplicable a diferentes realidades, los edificios analizados se encuentran no solamente en el centro histórico de Valencia, sino también distribuidos en la Comunidad Valenciana. Entre estos estudios necesarios está, en primer lugar, el diagnóstico de las estructuras y, posteriormente, una vez identificados y entendidos los tipos y causas de degradación, el proceso de conocimiento previo a un proyecto continúa con la clasificación de las estructuras para estimar las características mecánicas de los elementos de madera. El texto concluye con el empleo del análisis dendrocronológico para la datación de estructuras de madera. / [CAT] Estudi històric de la fusta arquitectònica a la ciutat de Valencia. Anàlisi preliminar per a la conservació: identificació de fustes, anàlisi constructiva, diagnòstic, classificació i dendrocronologia Pel que fa a les estructures històriques de fusta, la recerca històrica, les anàlisis tipològiques i constructives, la classificació estructural "in situ" i el diagnòstic són la base de la seua conservació. La recerca descrita en el text d'aquesta tesi es centra en els forjats i cobertes de fusta de la ciutat de Valencia, amb alguns exemples de la Comunitat Valenciana. La recerca s'estructura en tres parts que tenen com a fil conductor la promoció de la conservació d'estructures històriques de fusta. La primera part es centra en la gestió del Gremi de Fusters i en el transport local de fusta, així com en la seua importació dels Estats Units, tractant de dibuixar la geografia de l'origen del material utilitzat en les estructures històriques de Valencia. La segona part versa sobre l'estudi tipològic i constructiu dels forjats i cobertes que actualment es trobem en Valencia intramurs. Després d'una aproximació als llocs, es fa una anàlisi sistemàtica dels exemples de forjats i cobertes a través d'una catalogació amb fitxes que finalment sintetitza la informació recollida per tal de delimitar les característiques dels diferents tipus i morfologies d'elements arquitectònics que caracteritzen aquestes estructures, mostrant la riquesa també de les morfologies més simples i més freqüents. Paral·lelament a aquesta síntesi tipològica és realitza també una anàlisi estadística de les dades dimensionals per a especificar les característiques dels elements constitutius. L'última part es centra en aspectes pràctics de l'anàlisi d'estructures de fusta necessaris per dur a terme correctament qualsevol projecte de restauració. Tractant-se d'una secció més pràctica, els edificis analitzats es troben no només al centre històric de Valencia, però també a la Comunitat Valenciana. Entre aquests estudis necessaris està, en primer lloc, el diagnòstic d'estructures i, una vegada identificat i comprès els tipus i les causes de la degradació, el procés de coneixement previ d'un projecte continua amb la classificació de les estructures per tal d'estimar les característiques mecàniques dels elements de fusta. El text conclou amb l'ús de l'anàlisi dendrocronològic per a datar les estructures de fusta. / Diodato, M. (2015). Estudio histórico de la madera arquitectónica en la ciudad de Valencia. Análisis previos para la conservación y puesta en valor: identificación de maderas, análisis constructivo, diagnóstico, clasificación y dendrocronología [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/58606 / TESIS