Volume 18 Issue 3

Calamus caesius, one of the most valuable high-quality rattans, has emerged as an economical material for use in commercial products. This study systematically investigated the anatomical and microstructural characteristics of Calamus caesius in terms of the frequency, radial diameter, tangential diameter, and form factor of the vascular bundles in both inner and outer regions, as well as the frequency, proportion, length, diameter, and length-diameter ratio of the vessel elements, and the size, double wall thickness, lumen diameter, and ultrastructure of the fibers. The results revealed that the sizes of both vascular bundles and vessel elements in the inner regions were larger than the outer regions, while the fiber proportions and morphological features remained relatively constant. The fibers have a multi-layered structure, most of which exhibited a four-layered structure in their secondary walls. The properties of various tissue structures reflect rattan’s desirable characteristics for use as high-quality commercial timber.

In forest environments, the establishment, survival, and recruitment of seedlings of desired species can often be influenced by biotic interactions between the competing understory shrubs and the seedlings, as well as by the understory light environment. Previous studies regarding competing effects were mostly focused on the survival and growth of seedlings, but it is still largely unclear how competition with shrubs impacts the biomass of the seedlings and physiological traits connected to photosynthesis and nitrogen metabolism in various forest ecosystems. Moreover, there is limited knowledge on the influence of light conditions on the biomass of understory seedlings is limited for different species. The main objectives of this study were to examine the effects of understory junipers and light conditions on the above and belowground biomass of black pine seedlings (Pinus nigra Arnold). This study also examined the changes in chemical composition and plant nutrient contents in the organs of black pine seedlings (i.e., root, stem, and needle) with the presence of junipers in the understory. Seedling biomass was significantly affected by understory light conditions, while the presence of junipers negatively affected the root-biomass of black pine seedlings. Moreover, understory junipers influenced some photosynthetic pigments in black pine seedlings.

The durability of a pallet affects the amount of use a pallet can withstand before functionality is lost. A reliable prediction of durability can be used to determine the effect of pallet performance on supply chain operating costs. The objective of this research was to correlate damage modes, location, severity, and frequency observed for pallet in the field, to damages observed during Virginia Tech’s FasTrack simulation system. Several 1219 mm x 1016 mm (48 x 40 inch) stringer class wooden pallets used in the field were inspected for damages, and the results were compared to historical pallet damage information from FasTrack. The pallet damage behavior did not change for different levels of damage severity, which indicates that pallets fail as the initial damage worsens due to prolonged use. Inspected pallets from the field showed high damage occurrence on the stringer notches and bottom lead deckboards. Pallets tested via FasTrack exhibited significantly more top deck and end board damage and less stringer damage than observed in the field.

Effects of guayule resin on mechanical, physical, and biological performance of wood strand-based panels were evaluated. Southern yellow pine (Pinus spp. L) wood strands were mixed with phenol formaldehyde (PF) resin to a target resin content of 5% and hot-pressed to manufacture wood strand-based panels. A guayule resin solution was prepared and sprayed on the wood strands immediately after PF resin to different guayule resin contents of 0.5% and 1.0%. Specimens cut from treated panels and control panels were subjected to tensile, internal bond, water absorption and thickness swelling, and fungi soil block tests. Guayule resin had a positive effect on tensile strength, as specimens showed 8.0% and 9.5% increase compared to control specimens. However, the internal bond strength decreased 5.3% and 6.4%, respectively. Water absorption and thickness swelling for the treated specimens with guayule resin decreased as compared to control specimens. The fungal decay resistance test indicated little differences in the average percent mass loss across the untreated and treated wood strand-based composite materials. Regardless of increase or decrease, the effects of guayule resin on mechanical, physical, and biological performances of wood strand-based panels were not statistically significant.

Microencapsulated phase change materials (MPCMs) incorporated into oak wood via vacuum impregnation have shown promise as thermal energy storage (TES) materials. Physical and chemical properties of MPCMs and resulting Phase Change Energy Storage Wood (PCESW) were analyzed. Scanning electron microscopy and particle size analyses revealed similar particle sizes, while X-ray diffraction (XRD) and Fourier transform infrared spectra confirmed crystal phase and chemical structure. Thermal gravimetric analysis (TGA) and differential scanning calorimetry determined thermal properties, including phase change temperature, enthalpy, thermal stability, and conductivity. The MPCMs exhibited a phase change enthalpy of 146.0 J/g and temperature of 35.0 °C, with excellent thermal stability. The FTIR, XRD, and TGA analyses showed unchanged chemical structure, crystallinity ratios, and decomposition in two stages, respectively. The PCESW exhibited a latent heat storage of 3.02 J/g at 25.4 °C. Decay tests demonstrated noticeably reduced weight loss (1.22% and 1.55%) for MPCMW samples treated with Trametes versicolor and Coniophora puteana, compared to unleached control samples (19.7% and 20.8%). These findings indicate the high efficiency and potential of PCESW as a thermal energy storage material.

Cellulose is a biopolymer that has broad potential applications including in building insulation, and it was studied for its potential as a filler material. A closed-cell polyurethane foam insulation formulation was developed, and cellulose filaments (CFs) were introduced at varying percentages. The viscosity and morphology of the formulations were studied, as were different foam properties, such as water vapor permeability, reaction kinetics, density, porosity, thermal conductivity, and compressive strength foams as a function of cellulose filaments content. A commercial foam was also tested as a reference. The cellulose filaments impacted the formulations’ viscosity, and all the properties of the resulting insulating material. For example, samples containing 5% of cellulose filaments were found to perform differently than samples containing 0%, 1% and 2.5% mainly due to agglomerate formation, which impacted cell size (about 0.1 mm² at 0%, 1% and 2.5% versus a mean of over 0.4 mm² at 5%), and differential vapor sorption (with a mass change of 2%wt at 0 parts per hundred of polyol versus 2.5%wt at 5% from 0% to 95% relative humidity). However, the required performances by the standards of polyurethane foam insulation material were always fulfilled regardless of the amount of cellulose filaments present.

Herein, a beech wood dowel reinforced with a self-tapping screw (composite dowel in brief) is proposed. Composite dowels were welded into the predrilled holes by high speed rotation. Force-displacement curves were obtained using a single-shear and dual connection. A double-peaked pattern was found in the bearing process, indicating that the wooden dowel and the self-tapping screw had a synergistic bearing effect in the bearing process. Regarding the failure mode, the self-tapping screw and the wooden dowel were bent, whilst the default wooden dowel fractured. Further, the numerical simulation was carried out using the finite element analysis software ABAQUS, and the result differed from the test value by only 4.30%, showing a high prediction accuracy. The study of the bearing capacity of the composite dowels provides a theoretical basis for the practical application of wooden dowels reinforced by self-tapping screws.

Laminated veneer lumber (LVL) and modified grain orientation of LVL (LVB) are composite products made from veneer that are predicted to replace construction timber. The purpose of this study was to determine the physical and mechanical properties of LVL and LVB of mahoni (Swietenia macrophylla), manglid (Manglietia glauca), and gmelina (Gmelina moluccana) and to compare their characteristics. The results showed that the physical and mechanical properties of LVL and LVB generally meet the standards for use in construction. Differences in the properties of LVL and LVB occurred in the properties of hardness and screw tests, while the other properties were similar. The parallel fiber direction was better in terms of adhesive strength, while the compaction density was slightly higher than LVL. The LVL flexural strength was better than LVB in flat and edge test directions. This difference correlates with the adhesive strength in the shear strength test due to the different orientation of the fiber directions.

This study was conducted to examine the ameliorative effects of foliar application of some micro-algal (Chlorella vulgaris and Spirulina platensis) and some medicinal plant leaves (Salix alba, Psidium guajava, and Olea europaea) extracts on Phaseolus vulgaris (Bean) under salinity stress. On a loamy soil, a pots trial was carried out on bean plants grown under salinity stress. Growth characteristics, pigments, osmolytes, total phenol, and antioxidant enzyme contents were determined. S. platensis extract application showed the greatest improvement in shoot length and fresh weight of shoot, which rose 23.5% and 65.1%, respectively compared to the control. The utilized bio-stimulants, particularly S. platensis extracts, remarkably increased the chlorophyll content compared to the control under salinity stress. The photosynthetic pigment, soluble sugars, and soluble protein levels were strengthened by foliar application of bio-stimulant extract. Proline and antioxidant enzyme levels are significantly reduced using algal and plant extracts treatment. These findings support the treatment’s increased contribution to reducing salt stress and their detrimental effects on bean plants.The findings of this study indicate that the use of these biostimulants, especially S. alba, P. guajava, and O. europaea leaf extracts can be considered as an unconventional, ecofriendly, and novel tool in the mitigation of salinity stress.

The present study aims to identify the relations between the wood production (m³ per year) of the black pine (Pinus nigra Arnold.) and its habitat characteristics in the Eastern Mediterranean Region. A total of 120 samplings with different aspects, site altitudes, and site classes were studied. In each sample area, at least 5 trees were designated, and soil samples were taken by excavating earth pits. Certain characteristics of the soil samples were identified in the laboratory environment. The relations between the dominant height values of the trees in the sample areas and soil, climate, and physiographic factors were analyzed using correlation analysis, multiple regression analysis, and artificial neural network methods. Significant relations between the wood production values of the trees in the sample areas and slope from physiographic habitat characteristics, average annual temperature from climate characteristics, and pH and total carbonate from soil characteristics were found. The wood production of black pine was explained by multiple regression analysis at a level of 22.4% and by artificial neural network method at 72%.