Volume 19 Issue 3

Scots (Pinus sylvestris L.) and red pine (Pinus brutia Ten.) structural timbers (540 pieces) from Türkiye were first visually graded according to TS 1265 (2012). Then, non-destructive tests were conducted using vibration and time of flight (ToF) methods, followed by destructive tests on a four-point bending test setup according to EN 408 (2012). The vibration method showed a higher correlation than ToF with strength and stiffness. The dynamic modulus of elasticity (MOE_d) obtained by the vibration method was 12.3% and 15.4% lower in Scots and red pine, respectively, compared to the ToF method. Mechanical testing determined local MOE was 14% and 15% higher than global MOE for Scots and red pine, respectively. An alternative formula to the existing conversion formula in EN 384 (2018) was derived. The average bending strength of red pine was 7% higher than Scots pine. For visual strength grading, local and global MOE in Scots pine, class 1, 2, and 3 structural timbers were assigned to C35, C27, and C22, respectively. Red pine was assigned to C40, C27, and C24 for local MOE and C35, C24, and C22 for global MOE. In machine strength grading, the grade combination was C40-C30-C22-C16-R for both species. The best results were achieved in settings where vibration method and local MOE were used together. Machine strength grading achieved higher efficiency than visual strength grading.

To obtain a more appealing wood coating with lighter color, bleaching treatment was employed. Bleached and unbleached bio-polyurethane (PU) coating was prepared using liquefied bamboo and was applied to rubberwood. The coated wood surface was examined for adhesion, scratch, abrasion, impact, and resistance to common household chemicals. The results revealed that the bleaching of liquefied bamboo exerted mixed effects on the finishing properties of the bio-PU coating. Specifically, the surface coated with unbleached bio-PU coating exhibited noticeably higher levels of scratch and impact resistance compared to the surface coated with bleached bio-PU coating. However, both the adhesion and abrasion properties were found to be similar in both cases. Both bleached and unbleached bio-PU coating exhibited similar resistance to various household chemicals, with exception of acetic acid. This research demonstrated a method for producing semi-transparent bio-PU from bamboo biomass for use in wood coating. Bleaching treatment is feasible to produce light-colored coating without significantly affecting the finishing properties of the bio-PU coating.

The color-changing effect of tannin, which is a sustainable and environmentally friendly material used in wood preservation, was studied on varnished and un-varnished wood samples. For this purpose, walnut tannin was applied on samples prepared from Scots pine (Pinus sylvestris L.) and walnut (Juglans regia L.) wood in accordance with ISO 3129 (2019) standard with a brush, and then samples were coated with polyurethane varnish and water-based varnish according to ASTM D3023-98 (2017) principles. Color changes were determined according to ASTM D2244-21 (2021). The obtained data indicated that the highest value in the red color tone (a*) was observed in Scots pine+tannin+polyurethane varnish (PU) (14.4) and the lowest was in Scots pine+control+unvarnished (Uvr) (6.5). The highest value for the yellow color tone (b*) was observed in Scots pine+tannin+PU (34.1), the lowest was in walnut+control+Uvr (14.4), and the highest color lightness value (L*) was obtained in Scots pine+control+Uvr (77.0), and the lowest was obtained in walnut+tannin+PU (18.9). The tannin application, which darkened the wood surface, increased the a* and b* values in both wood types while decreasing the color lightness values 60% to 70%. Tannin application caused a noticeable decrease in total color changes in Scots pine.

Ferns native to Korea, such as Davallia mariesii, Dicranopteris pedata, and Gleichenia japonica, possess antioxidant and antibacterial properties. However, their inhibitory effects on skin photoaging have not been demonstrated. Measurement and comparison of the antioxidant activity of three types of ferns revealed that the extract from G. japonica had the best effect. This study evaluates the potential of G. japonica extract as a new functional material for preventing skin damage caused by ultraviolet radiation. G. japonica extracts showed protective effects against ultraviolet B (UVB) radiation in human epidermal keratinocyte cells; the extracts inhibited intracellular reactive oxygen species production. In addition, collagen biosynthesis increased, and matrix metalloproteinase-1 activity and protein expression level decreased in human primary dermal fibroblast irradiated with UVB. The main peak (compound 1) of the extract was separated through high-performance liquid chromatography analysis and preparative liquid chromatography. Compound 1 is strongly inferred to be the main active ingredient because it showed better antioxidant activity and UVB protection effect than G. japonica extract. These results demonstrate the physiological effects of G. japonica extract and suggest its applicability as a new functional substance for preventing skin damage caused by ultraviolet radiation.

In today’s wood industry, research is being conducted to increase material strength, ensure long-term use, and increase its hardness against many harmful external factors. With the studies on the protection of wood, new protection materials and methods are introduced. In this study, wood was etched with solid sodium bicarbonate (NaHCO₃) and 1, 2, and 3 bars of air pressure after treatment with NaHCO₃ solution and drying. The change in hardness values of impregnated and surface-treated (paint, varnish) chestnut wood after artificial aging was examined. Etching, impregnation, and surface treatment factors were optimized using the Taguchi design of experiments (DoE) after artificial aging for 3, 6, and 9 months. L16 orthogonal array was used to determine the optimum conditions for determining hardness values and their percentage changes. The results showed that the abrasive factor prevails over the effect of surface treatments. It has been understood that the most effective factor in the hardness value changes during the artificial aging period (3-6-9 months) is abrasion, and the factor with the least effect is the surface parameter. The percentage accuracy of the model used in estimating the wear factor average R² across all dependent variables was 95%.

By using 16 simple sequence repeat (SSR) markers, the genetic relatedness of 21 exceptional walnut genotypes was assessed. A significant degree of genetic diversity was observed within a given population, as indicated by the number of alleles per locus ranging from 2 to 4. WGA-1, WGA-4, and WGA-79 contained the greatest number of alleles (4), followed by WGA-118, WGA-202, and WGA-42. Conversely, WGA-27, WGA-69, and WGA-32 contained the fewest alleles. The range of the PIC value was 0.11 to 0.38. Using model-based cluster analysis, all genotypes were categorized into two primary clusters according to the UPGMA dendrogram, with varying degrees of sub-clustering. All the genotypes were categorized into six genetically distant subpopulations. The genotypes were genetically distinct but had variable degrees of admixture. The anticipated heterozygosity at a specific locus ranged from 0.563 to 0.741. Additionally, population differentiation (Fst) ranged between 0.176 and 0.261. These findings highlight the importance of considering germplasm diversity in walnut breeding programs and conservation efforts aimed at enhancing walnut cultivation in the region. Overall, this study contributes to our understanding of walnut genetic diversity in the Northwestern Himalayan region of Jammu and Kashmir and informs future breeding and conservation strategies.

Generation of lignin-carbohydrate complex (LCC) between dehydrogenation polymer (DHP) and pulp fibers may have an important impact on the properties of pulp. In this work, the benzyl ester-type LCC was formed between oxidized cellulose and DHP. The effect of pH on the addition reaction of oxidized cellulose to quinone methide in the synthesis of DHP-cellulose complex (DHPCC) was investigated. The structure of the product was characterized by Fourier Transform Infrared (FTIR), Carbon 13-Nuclear Magnetic Resonance (¹³C-NMR), and 2-Dimensional Heteronuclear Single Quantum Coherence Nuclear Magnetic Resonance (2D HSQC NMR) analyses. The results indicated that cellulose was indeed oxidized and carboxyl groups were introduced into cellulose by the oxidation process. The formed DHPCC was connected by benzyl ester linkage. In addition, the pH of the reaction system had an important role in the formation of the benzyl ester bonds. The acidic condition (pH = 4.0) was conducive to the addition reaction of quinone methide with carboxyl groups of cellulose. Overall, this study provides helpful guidance for the generation of LCC between DHP and paper pulp fibers.

The disposal of agricultural waste ash is a great ecological challenge. This study analyzed the basic properties of corn straw ash and soybean straw ash, encompassing the identification of key oxides, the assessment of particle size distribution, and the performance of thermogravimetric analysis. This study also evaluated the potential of corn straw ash and soybean straw ash to replace cement in mortar and concrete through laboratory tests. The findings indicated that the strength activity index of corn straw ash was higher than soybean straw ash. Furthermore, when these ashes were used as cement replacements, the compressive strength of concrete decreased. Notably, concrete containing corn straw ash exhibited greater strength than concrete with the same substitution amount of soybean straw ash. Specifically, at a 5% substitution level, the compressive strengths of corn straw ash concrete and soybean straw ash concrete were 31.5 and 30.5 MPa, respectively. Additionally, soybean straw ash concrete demonstrated superior resistance to water penetration compared to corn straw ash concrete. Both corn straw ash and soybean straw ash exhibited the potential to enhance the early crack resistance of concrete.

The purpose of this study was to use ultrasound-based extraction to prepare starch from the tubers of Cyperus esculentus. Ultrasonic treatment of Cyperus esculentus powder with a medium of alkaline-treated water can effectively improve the starch extraction efficiency. Box-Behnken design was used to optimize the extraction process, and the results showed that the optimal parameters were ultrasound time of 30 minutes, pH value of 9.0, ultrasound temperature of 40 °C, and solid-liquid ratio of 10:1. The extraction percentage under these conditions was 90.1%. The physicochemical properties of C. esculentus starch were compared with those of cassava, potato, and corn starch. The particle size of C. esculentus starch was approximately 2 to 15 μm. The gelatinization temperature was 70.5 °C, and the peak viscosity was similar to cassava but with better thermal stability. Like other tuber starches, C. esculentus starch had higher swelling power and solubility at 85 °C.

Hydrothermal liquefaction (HTL) is an efficient technology for converting biomass to platform compounds. It has great potential for reducing the dependence on fossil fuels. The HTL of waste biomass has been extensively studied in recent years due to both its environmental and economic benefits. However, most woody waste contains a large amount of cellulose, and it is difficult to be sufficiently decomposed to valuable chemicals. Phycocyanin, a key component of algae, is easily degraded under high-temperature liquefaction conditions. In this work, focusing on bio-oil generation properties, the co-liquefaction characteristics and synergistic mechanisms of α-cellulose and phycocyanin were explored. The findings revealed a maximum bio-oil yield of 33.1 wt% under the optimal conditions (300 °C for 40 min), with a notable positive synergistic effect of 13.5 wt%. Chemical composition analysis indicated distinct compositional differences between the bio-oils derived from individual and dual feedstock. The amounts of pyridine and pyrimidine compounds increased due to the enhanced co-liquefaction. The results also highlighted the influence of temperature on the degree of conversion and product distribution. Finally, preliminary chemical reaction pathway was elucidated, underscoring the potential of integrating microalgae and woody biomass for enhanced bio-oil production.