Research Articles

Crane mats provide safe, stable, and flat work surfaces for heavy equipment and provide environmental protection. In this manuscript, two types of three-ply mats from two geographic regions were evaluated for stiffness and strength. Mats were sourced from the Southern USA and Midwestern USA in both solid configurations where the boards in all plies are touching and waffle configurations where gaps of approximately 1.8 inches were left between boards. Both types were mechanically fastened with regularly scheduled 3/8th inch diameter carriage bolts. The mats consisted of 1.5-inch-thick mixed oak and hardwood lumber oriented in a similar manner to plywood to form 4.5-inch-thick panels, each of which is 8 ft x 14 ft. Mats were prepped for testing by being ripped into strips 24 ± 4 inches wide. In this manner, 28 test specimens were developed from 7 parent mats. Mats were subjected to three-point bending tests. In both types of mats, the Southern-sourced specimens were statistically stronger and stiffer than those from the Midwest. Modulus of rupture (MOR) results showed that solid mats from the South were stiffer compared to waffle configurations produced in either location. The regression analysis indicated that modulus of elasticity could potentially estimate MOR.

This study was conducted to devise ways of promoting the use of deciduous trees that have increased in number with climate change. For six oak species commonly utilized to produce liquor barrels, normal wood and tension wood were classified by part. Then, both large vessel lumen area and tyloses were quantitatively assessed. The findings showed that in both normal and tension woods, large vessel lumen area was largest in sapwood, followed by heartwood and juvenile wood. Tyloses were found in both normal and tension woods of all the six species, but the number of tyloses varied according to species. It was heart wood that contained the highest amount in both normal and tension woods. It was also revealed that the number of tyloses decreased with the growing area of large vessel lumen. This study will provide fundamental data to decide oak tree species for the production of liquor barrels.

Salix psammophila (SP) is an important sand plant, and could be utilized to develop high-value products. In this work, SP was used as raw material and cellulose nanocrystals (CNC) were prepared by hydrolysis in 64 wt% sulfuric acid (H2SO4) solution, and then, TEMPO/NaBr/NaClO system was used to oxidize CNC to obtain TEMPO-oxidation-cellulose nanocrystals (TOCNC). Fourier transform infrared analysis (FTIR) revealed that after oxidation, there were obvious carboxyl functional groups. Scanning electron microscopy (SEM) showed that both CNC and TOCNC were agglomerated. Under atomic force microscope (AFM) and transmission electron microscopy (TEM), CNC and TOCNC presented short rod fibers, average diameters of 23 nm and 21 nm and average lengths of 213 nm and 165 nm, respectively. X-ray photoelectron spectroscopy analysis (XPS) showed that TOCNC generated a new energy spectrum peak at 289.06 eV, which was the peak of C=O in the carboxyl group. The crystallinity of the CNC and TOCNC were 70.8% and 26.9%, respectively.

The aim of this study was to evaluate the differences between juvenile and mature woods of Populus alba trees in the axial and radial directions of the stem. For this purpose, three stands of P. alba trees were randomly chosen and cut from at their diameter at breast height. Three disks with a thickness of 5 cm were taken at three different height levels along the tree stems. The specimens were sequentially cut in the radial position according to the ISO standards method. The results indicated that there are significant differences in the physical and biometric features of P. alba trees in the longitudinal and radial axes of the stem. As the height from the base of the tree to the top of the stem increased, the oven-dry density, basic density, and fiber biometric factors decreased. Moreover, as the distance from the pith to the bark increased, the oven-dry density, basic density, and fiber biometric factors increased. The microscopic study represented that the P. alba is a semi-ring-porous hardwood with distinct growth ring boundaries, simple perforation, homogenous rays, and alternative inter-vessel pits.

This study investigated the effect of cutting conditions effects on sound level and surface quality in softwood and hardwood. The sound emission level caused by cutting process (band saw) as well as the surface roughness and topography of the wood samples were evaluated. A direct relationship was found between sound emission level and density, moisture content, feeding rate, and dimensions of the samples. Straight cutting of the samples caused less sound emission than cutting in a curved direction. The protective effect of the earmuffs was very significant, reducing the sound emission level from 88 dB to 38 dB. The results showed that with increasing the density and dimensions of the samples, the surface roughness decreased, while with increasing the moisture content and feeding rate, changing the cutting direction from straight to curved, the surface roughness of the samples increased.

Before timber is used for engineering and structural purposes, it is necessary to grade the strength of the timber. In order to obtain the static modulus of elasticity value of timber quickly and accurately, this study used ultrasonic waves and continuous mechanical stress rating equipment and two non-destructive test methods to analyze the correlation between the non-destructive test measured value and the static modulus of elasticity value. It also evaluated the influence of the feeding orientation of the boards, the forward and reverse feed directions, feeding speed, and break area ratio. The analysis results indicated that the modulus of elasticity value determined through continuous mechanical stress rating equipment had the highest correlation with the static modulus of elasticity value. Moreover, according to the results, the feeding orientation of the boards, the forward and reverse feed directions, and the feeding speed did not influence the prediction of the continuous mechanical stress rating equipment modulus of elasticity value. Meanwhile, to ensure the accuracy and uniformity of the continuous mechanical stress rating equipment modulus of elasticity detection value, it is necessary to avoid an excessively high break area ratio in Cunninghamia lanceolata timber during the preparation process.

The flange of press-formed paperboard trays was reshaped in this work with a developed folding method to increase the rigidity of the trays. The tray rigidity was evaluated with compression, torsion, and storing tests. The rigidity of the folded trays and the reference trays was compared, and the quality of the trays was investigated with an optical analysis. The folding temperature was altered to 23, 60, and 90 °C to compare the effects of heat input on the tray rigidity. The compression and torsion test results linked the increased tray rigidity to the additional heat input and surface pressure induced to the material in the folding phase. The trays that were folded at 90 °C showed a 43% higher compression force and a 12% smaller torsion angle compared to the reference trays. The storing tests showed an unclear effect on the tray rigidity to the dimensional stability, and the optical analysis depicted similar quality between the folded and the reference trays. The folding method was found to enhance the stacking and end use capabilities of paperboard tray packages, and the use of higher folding temperatures was suggested to increase the strength and stiffness of the trays.

The anatomical characteristics in the culms of the four promising Indonesian bamboo species, including Dendrocalamus asper, Dendrocalamus giganteus, Bambusa vulgaris var. vulgaris, and Bambusa vulgaris var. striata, were investigated to produce an identification key and quality indices for further effective utilization. The crystalline properties of the bamboo culm were determined using X-ray diffraction analysis. Dendrocalamus asper and Bambusa vulgaris var. striata showed vascular bundle type IV, while Dendrocalamus giganteus and Bambusa vulgaris var. vulgaris displayed vascular bundle type III. The vascular bundle density in the bamboo culms increased from the bottom to the top part and was higher in the outer part than in the inner part. The fiber portion and length in the outer part were higher than those in the inner part, opposite of those in the parenchyma portion. Dendrocalamus giganteus had the largest vessel and parenchyma diameter, while Bambusa vulgaris var. vulgaris had the smallest. Bambusa vulgaris var. vulgaris had the longest parenchyma, while Bambusa vulgaris var. striata and Dendrocalamus giganteus had the shortest. The outer part of the four bamboo culms showed higher relative crystallinity than the inner part. All anatomical parameters, except for crystallite width, showed a variation in the radial direction of the four bamboo culms but did not show a consistent tendency vertically. This study revealed that the anatomical properties were different between bamboo species and could be used for species identification and quality evaluation indices of the culms.

The carbohydrate composition (glucose, xylose, mannose, galactose, and arabinose) of lignocellulosic biomass Liriodendron tulipifera, Populus nigra × Populus maximowiczii, Populus alba × Populus glandulosa, Populus euramericana, Salix alba, Quercus variabilis, Robinia pseudoacacia, Zelkova serrata, Abies holophylla, Pinus rigida, rice straw, and peanut hull was investigated based on high-performance liquid chromatography (HPLC) and gas chromatography (GC) analyses derived from ASTM and NREL methods. The glucose content was higher in HPLC than in GC analysis, and the xylose, mannose, galactose, and arabinose contents were higher in GC than in HPLC analysis. The difference in carbohydrate composition was noticeable in the glucose, mannose, and arabinose contents of Abies holophylla and Pinus rigida, and this was affected by the species. A decision tree, as a data mining and artificial intelligence method, is a reliable and simple variable selection tool. This technique was used for carbohydrate analysis classification. Accordingly, 432 monosaccharide content reading data and analysis methods were used for model checking. It was found that arabinose was the most important splitting variable in carbohydrate analysis, and other monosaccharides did not influence the assay decision. However, the selection of a determination method for each sample should be considered comprehensively in future studies.

During the simulation analysis of the discrete element method (DEM) for the alfalfa compression process, the input parameters in DEM software had a significant effect on simulation results. To obtain simulation parameters of the alfalfa with different moisture contents, a combination of angle of repose tests and simulation optimization design are presented in this paper. The repose angle of the alfalfa with moisture contents of 2.7%, 13.4%, 19.9%, 33.1%, and 74.5% was measured, and the results were 41.99˚, 38.30˚, 47.47˚, 56.31˚, and 63.09˚, respectively. Inclinometer tests, shear test, and restitution test were performed to evaluate the contact parameters. Taking contact parameters as the calibration object, the Plackett-Burman test was used to screen out which parameters had significant influence on the repose angle. The results of variance analysis showed the surface energy was the most significant parameter in the alfalfa repose angle test for each moisture content. Based on the Box-Behnken test, a second-order regression model of repose angle was obtained and the significance parameters were optimized and calibrated. The parameters calibrated in this paper can provide a reference for other simulations of alfalfa utilization.