Joseph Dahlen

Assessment of the early signs of decay of Populus deltoides wafers exposed to Trametes versicolor by near infrared spectroscopy

Abstract The use of near infrared (NIR) spectroscopy to predict levels of white-rot degradation in Populus deltoides (cottonwood) by Trametes versicolor over the couse of 1–8 days was investigated. NIR spectra were collected from cross-sectional faces following laboratory soil block decay tests. Spectra in the range of 1100–2400 nm were calibrated in terms of mass loss, compression strength and exposure period based on data of standard methods. The first and second derivatives of NIR spectra were also included into the calibration, which was done by partial least squares regression. The best calibrations with the strongest R2 values were obtained in terms of exposure period (R2 0.92, second derivative), mass loss (R2 0.89, first derivative) and compression strength (R2 0.51, second derivative). As far as the validation (prediction) statistics are concerned, the following data were obtained: exposure period (R2=0.71; RPDp 1.81, second derivative), mass loss prediction (R2=0.43; RPDp=0.67, first derivative) and compression strength R2=0.28; RPDp=1.14 (second derivative). The weak statistical data can be interpreted only in a way that the data are not robust and thus an early prediction of fungal attack by NIR spectroscopy is not yet reliable.

Evaluation of the Performance of Composite Wood Decking Bonded with Phenol Resorcinol Formaldehyde and Polyurethane Adhesives after Accelerated Aging Tests

Abstract The feasibility of applying an innovative process to manufacture composite decking boards with quartersawn or starsawn southern pine lumber bonded with phenol resorcinol formaldehyde (PRF)...

Hazardous Air Pollutants and Volatile Organic Compounds Emitted during Kiln Drying of Southern Pine Lumber to Interior and Export Moisture Specifications

The emission levels of hazardous air pollutants (HAPs) from wood kilns are needed to comply with the Clean Air Act. Softwood lumber, including southern pine (Pinus taeda, Pinus palustris, Pinus echinata, and Pinus elliottii), is considered kiln dry when the wood moisture content reaches below 19 percent, but it is sometimes overdried or dried to 8 percent moisture content for export or interior applications. To study HAP emissions when drying to 8 percent moisture content, green lumber was obtained from a local mill, and 12 charges were kiln dried using three schedules: a 99°C elevated schedule and 116°C and 127°C high-temperature schedules. Methanol and formaldehyde were collected and analyzed using the National Council for Air and Stream Improvement (NCASI) 98.01 method, “Chilled Impinger Method for Use at Wood Products Mills to Measure Formaldehyde, Methanol, and Phenol,” where formaldehyde was analyzed via spectrophotometry using acetylacetone and methanol was analyzed via gas chromatography with a fl...

Relationships between Static Mechanical Properties and SilviScan Measured Wood Properties in Loblolly Pine

Abstract Relationships between static bending modulus of elasticity (MOE) and SilviScan (SS) properties (SilviScan MOE [MOESS], specific gravity, and microfibril angle) were explored. Seventy-three clearwood specimens (25 by 25 by 406 mm) were cut from thirty-two 33-year-old loblolly pine trees. Relationships were calculated between MOE and MOESS (R2 = 0.77); however, MOESS, calibrated using sonic resonance, averaged 25 percent higher than static MOE. Calibrating MOESS to static MOE instead of sonic resonance MOE resulted in similar prediction performance (R2 = 0.77), but more importantly approximately equal prediction values. The results demonstrate the importance of properly utilizing SilviScan information for predicting loblolly pine properties in static bending.

A quantitative method for analyzing glycome profiles of plant cell walls

Glycome profiling allows for the characterization of plant cell wall ultrastructure via sequential extractions and subsequent detection of specific epitopes with a suite of glycan-specific monoclonal antibodies (mAbs). The data are often viewed as the amount of materials recovered and coinciding colored heatmaps of mAb binding are generated. Interpretation of these data can be considered qualitative in nature as it depends on detecting subtle visual differences in antibody binding strength. Here, we report a mixed model-based quantitative approach for glycome profile analyses, which accounts for the amount of materials recovered and displays the normalized values in revised heatmaps and statistical heatmaps depicting significant differences. The utility of this methodology was demonstrated on a previously published dataset investigating the effects of moisture stress on the roots and needles of Pinus taeda. An annotated R script for the quantitative methodology is included to allow future studies to utilize the same approach.

Volatile Organic Compounds Emitted during the Kiln Drying of Southern Pine Utility Poles

Southern pine is the most common species used for utility poles in the United States. However, information regarding air emissions from pole drying is very limited. With respect to drying, poles ha...