Volume 19 Issue 3

To improve the material properties of wood-plastic composite, poplar fiber and polyethylene powder were used as the main components, a hot-press experiment was conducted using response surface methodology, and the relationship between processing parameters (wood/plastic ratio, hot-press pressure, and time) and experimental result (internal bond strength and thickness swelling) were explored. According to the experimental results, the increasing wood/plastic ratio led to the lower internal bond strength and higher thickness swelling. However, with the increase of both hot-press pressure and time, internal bond strength increased first and then decreased, and thickness swelling decreased first and then increased. Meanwhile, two mathematical models were developed with high feasibility, and the significance of the influence of each term in the models was also analyzed. The models were able to predict and optimize internal bond strength and thickness swelling. Finally, optimal processing parameters were determined as wood/plastic ratio of 1.09, hot-press pressure of 198.38 MPa, and hot-press time of 8.31 s, with respect to the higher internal bond strength and the lower thickness swelling. This work hopes to provide scientific support for the industrial processing of wood-plastic composite.

Plants represent a great source of medicines, and for their components to be discovered, extraction processes must be developed, especially methods based on green technology. Supercritical fluid extraction (SFE) was employed as a green method for Moringa oleifera extraction in the present investigation. The maximum yield of extraction was obtained at 25 MPa. Moreover, the extraction at 25 MPa induced the release of various phenols and flavonoids, as analyzed via high-performance liquid chromatography. The investigation revealed the concentrations of chlorogenic, gallic, rosmarinic, and coumaric acids to be 150.59, 89.90, 44.75, and 29.41 µg/mL, respectively at 25 MPa. However, their concentrations were 0.73, 1.53, 0.24, and 0.04 µg/mL, respectively at 15 MPa; vs. 4.73, 2.62, 1.06, and 0.50 at 35 MPa, respectively. Totals of saponin, flavonoid, phenolic, tannins, and alkaloid were recorded in maximum yield at 25 MPa. Moringa oleifera extracted at 35 MPa reflected highest inhibition zones of 27 ± 0.1, 30 ± 0.2, and 30 ± 0.1 mm against C. glabrata, C. tropicalis, and C. albicans, correspondingly. α-Amylase and α-glucosidase activities were greatly suppressed by the M. oleifera extract at 25 MPa with less IC₅₀ (12.97 µg/mL and 6.0 µg/mL), than the IC₅₀ (53.46 and 22.02 µg/mL) at 15 MPa, compared with acarbose IC₅₀ (5.52 and 2.64 µg/mL), correspondingly.

The influence of exogenous application of the amino acids Glutamic acid (Glu), Methionine (Met), L-Tryptophan (L-Try), and Lysine (Lys) at concentrations of 250 and 500 ppm was studied relative to the growth of peach trees. The trees were sprayed three times; before flowering, during full bloom, and one month later by 250 ppm Glu + 250 ppm Met + 250 ppm L-Try + 250 ppm Lys (combination 1) and 500 ppm Glu + 500 ppm Met + 500 ppm L-Try + 500 ppm Lys (combination 2), in comparison to trees that were not sprayed (control). A randomized complete block design was used. The individual application of four amino acids positively improved the shoot diameter, leaf chlorophyll, leaf area, and productivity as opposed to not spraying the trees. Additionally, the applied amino acids increased the fruit weight, size, firmness, length, and diameter, and the fruit content from the percentages of total soluble solids (TSS), TSS-acid, and anthocyanin contents, in contrast to the control. They also improved the fruit content from total, reduced, and non-reduced sugars as well as vitamin C and the leaf nutritional content from NPK. The application of combination 2, over the two seasons, was more beneficial.

The bordered pitting arrangements in the tracheids of Dahurian larch (DL) and Japanese larch (JL) growing in Korea were studied using optical microscopy to gain insights into the wood identification of both species. Differences were noted in the tracheid pitting patterns between the species. In juvenile wood, DL dominantly exhibited uniseriate pitting along the earlywood within a growth ring, whereas JL displayed biseriate pitting at the start of the earlywood, transitioning to uniseriate pitting. In the transition wood, DL predominantly showed biseriate pitting at the beginning, with uniseriate pitting at the end, while JL exhibited uniseriate pitting initially and at the end, with biseriate pitting in the middle. The mature wood of both species predominantly exhibited a biseriate pitting arrangement with a few uniseriate pitting at the end of the earlywood. JL exhibited a higher proportion of biseriate pitting than DL. The proportion of biseriate pitting and radial tracheid width in both species increased with increasing growth ring number, showing a positive correlation. While some differences were found between DL and JL, further investigation is needed to evaluate the consistency and practical applicability of pit patterns for wood identification in diverse field conditions.

Thermal modification processes are environmentally friendly methods used to improve certain properties of wood. Currently, wood from thinning of young plantations of Nothofagus alpina (raulí) in Chile is being evaluated to obtain value before the plantation has reached maturity. The objective of this paper was to assess selected properties of thermally modified wood of young (14- to 25-years-old) N. alpina wood that comes from thinning of two sites with intensive silviculture and one similar to a secondary growth forest. To achieve this, non-destructive tests were carried out to measure some chemical-crystalline characteristics, as well as physical and mechanical properties; the differences between the 25%, 50%, and 75% distance from pith to the bark in each site was studied. The modification temperatures used were 170, 190, and 210 °C. The results show that thinning wood from N. alpina can be thermally modified with favorable results, thus presenting an option to obtain value while the plantation reaches maturity, particularly the thinning wood from the intensive forestry regimes, which presented most homogeneous results, especially at the modification temperature of 190 °C.

This research investigated the influence of the layered structure of paper on its selected strength properties. Two types of cellulose pulp were used: unbleached kraft pine pulp (UBSK) and unrefined bleached birch kraft pulp (BHK). Multi-ply papers were obtained from layers of appropriate grammage formed separately and bonded in a wet state. Paper layers were formed from primary pulps (UBSK and BHK) or their mixtures (three-ply UBSK-BHK paper and three-ply UBSK-BHK-UBSK paper), from which various variants of laboratory paper samples were made. This work focused on three-layer papers. The obtained laboratory sheets were analysed for changes in tear resistance, tensile strength, bursting strength, short span compression strength (SCT), and corrugating medium test (CMT). In most cases, three-layer structures were characterised by higher strength parameters than single-layer papers. The tear strength and SCT of papers consisting of three layers formed from both mixed pulps were slightly lower than those of solid papers. The results demonstrate the feasibility of producing three-ply paper with significantly reduced variability in parameters such as elongation and bursting strength, which are inherently subject to high variability.

Some physical and mechanical properties of laminated timbers used in wooden construction and furniture industry were examined. Polyurethane (PU) glue was used in the production of laminates with 5 layers. The surface layers in each laminated timber (Glulam) were from the same wood type, and the core layers were from willow wood. The laminated timbers whose outer layers were made of willow (Salix alba L.), yellow pine (Pinus sylvestris L.), and ash (Fraxinus L.) wood had an air-dry density value of 0.60 g/cm³ in laminated timber with the highest ash wood surface. The pressure resistance parallel to the fibers was determined in the surface layer ash wood with 48.6 N/mm². It was found that the static bending resistance was 91.1 N/mm² in laminated timber with a surface layer of ash wood, and the modulus of elasticity value in bending was 10040 N/mm² in laminated timber with the highest ash wood surface. Thus, it has been seen in the study that improvements in physical and mechanical properties were achieved, especially as a result of combining willow wood (having fast growth potential and low density) with high-density wood types. According to the results of the study, it is recommended to carry out the necessary studies to increase the physical and mechanical properties of low-density wood types by laminating them with high-density wood types.

One of the biggest problems that threaten the production of strawberry in the world is the rapid damage and high rate of deterioration after harvest or during cold storage. Therefore, the current study was conducted to investigate the possibility of decreasing the post-harvest damage percentages and increasing the fruit quality of Fragaria x ananassa cv. ‘Estavana’ after harvest immediately or during the cold storage period. The strawberry plants were dipped for 3 to 5 minutes at 25 °C in a solution of 10 L made from distilled water and containing salicylic acid (SA) at 0, 250, 500, and 1000 mg/L or chitosan (CHIT) at 0, 2.5, 5, and 10 mg/L during the period of 0, 3, 6, 9, 12, and 16 days after harvesting. The results showed that the fruit firmness was notably decreased, and the loss and decay percentages were increased by increasing the period of storage, but it could be decreased by using SA or CHIT. Fruit content from soluble solids, total sugars and anthocyanin was significantly increased in the 16 days stored fruits treated with 500 mg/L SA or 50mg/L CHIT. Treating the fresh harvested without or with SA or CHIT increased the fruit content from vitamin C. The highest fruit content from titratable acidity was in the fresh harvested fruits compared with treated fruits with SA or CHIT.

To cope with low fertility rate and an aging population, China introduced and implemented a two-child policy to make an overall population adjustment. Because of this, there are now problems, such as the uncoordinated sleep space for the two children, competition between older children, insufficient care for older children, and additional family affairs. In view of this, this study focused on the two-child family and parents as the main users of wooden infant beds. The method of constructing I-Kano model was used to determine the needs of users and their importance. Based on the QFD theory, the user needs and engineering measures were analyzed and explored. Based on the TRIZ theory, the analysis of engineering conflict resolution was performed. Based on the results, the wooden infant bed design strategy was developed for the background of two-child policy. The purpose of this work is to meet the parenting needs of two-child families in various periods with the developed design strategy, avoid the parenting problems of two-child families, improve the parenting quality of two-child families, adjust the sleeping space of two-child families, and fill the vacancy in the design theory of wooden baby beds for two-child families.

Understanding the trajectory of changes in soil respiration (R_s) and soil organic carbon (SOC) with stand ages of the black pine (Pinus nigra Arnold) forest is essential for forest management and carbon budget estimates. In this research, changes of R_s and SOC were studied with respect to stand age in a chronosequence of three age classes of P. nigra plantations consisting of young (0 to 10-year-olds), middle-aged (11- to 20-year-olds), and pre-mature (35- to 45-year-olds) forest stands. R_s rates, soil temperature, and soil moisture were measured using an automated dynamic survey chamber (Li-8100A) for a year, encompassing summer, fall, winter, and spring seasons. Mean R_s significantly increased from young- to middle-aged and then stabilized, with effluxes ranging from 2.46 to 2.94 µmol CO₂ m^-2 s^-1. Forest litter significantly increased with stand age, but not the SOC in the mineral soil layers. The R_s showed a positive correlation with soil temperature (0.77) and air temperature (0.75) but not with soil moisture (-0.43). The present results highlight the importance of stand age in assessing carbon budget and provide essential information for forest managers and stakeholders in evaluating the potential of P. nigra forests as tools for carbon sequestration and mitigating global warming impacts.