Research Articles

Effects of different concentrations of biogas slurry (BS) were evaluated relative to vegetable cultivation. Five concentration levels of BS were used as organic fertilizer to grow Chinese cabbages (CA) by drip irrigation to study the effect of BS on the yield and quality. Each level was replicated three times and BS was used seven times. Results showed that the average plant height, fresh weight, dry weight, and soluble sugars and protein contents of Chinese cabbage under the T1 (BS 25%) treatment were optimal. Among them, dry weight per plant (3.53g), soluble sugar content (0.41%), and soluble protein content (0.0039%) were 1.74 times, 1.41 times, and 1.14 times more than under the CK treatment, respectively. In addition, the application of biogas slurry improved the physical and chemical properties of soil. Soil total nitrogen (TN) and available phosphorus (AP) content increased after the use of biogas slurry, and the soil total nitrogen and available phosphorus content increased with the increase in the concentration of the applied biogas slurry. The available potassium (AK) content of soil fluctuated with the concentration of biogas slurry. In addition, biogas slurry can properly improve soil pH. In conclusion, BS 25% was the best for the growth of CA and its quality, which provided scientific basis for biogas slurry as fertilizer.

Composite materials based on modified stems of Heracleum sosnowskyi (Sosnowsky’s hogweed) and polyurethane binder are used for thermal insulation of building structures. The purpose of this study was to create a mathematical model for the optimization of composite compositions and the prediction of their properties. Numerical methods of mathematical statistics were used and nomogram plots were obtained. It was possible to select optimal compositions for the given characteristics of composites based on modified stems of H. sosnowskyi and polyurethane binder and predict the thermophysical properties of composites by knowing their composition. To produce thermal insulation boards with a thermal conductivity coefficient of 0.05 W/(m°C) it was necessary to use particles of H. sosnowskyi with a size of approximately 5 mm. The ratio of plant raw material and polyurethane binder was approximately 3:1 by weight. The bending strength of the thermal insulation boards was 1.56 MPa, and the compressive strength was 0.27 MPa.

The effect of sticker thickness on final moisture content (MC) of southern pine lumber was investigated in this work. Three kiln charges of lumber were dried to examine the impact of sticker thickness. Sticker thicknesses were 0.75-, 1.00-, and 1.25-in. The moisture contents at different locations within the kiln pack (edge vs middle / course position) were noted. Three course positions were top 5, middle, and bottom 5 courses. Two within-pack locations were considered: outer 25% and middle 50%. Drying time decreased as sticker thickness increased from 0.75 in. to 1.00 in. Statistically significant interactions were noted for sticker thickness and course position (<0.0001) as well as location and course position (P= 0.0378); 1.25 in. thick stickers exhibited higher MC in comparison to 0.75 in. and 1.0 in. for top to bottom positions. Additionally, 1.0 in. thick stickers developed lower MC at the top and bottom. Lower MC was observed in outer relative to inner location regardless of course position. Lower MCs were observed at the top courses for both inner and outer location. The 1.25 in. thick stickers did not produce acceptably dry lumber given the production time constraint. The results suggested that 1.0 in. sticker thickness was most favorable.

The compound 5-(hydroxymethyl)furfural (HMF) has emerged as a versatile intermediate with the ability to undergo conversion into both fuel and a variety of platform chemicals. Lignocellulosic biomass, such as hazelnut shells and tea processing residues, was employed in this study for HMF production through two distinct methods. In the first method, cellulose from biomass was converted to sugars using a 4% acid solution, followed by catalytic conversion with NaCl/CrCl₃.6H₂O. After a 1-h reaction at 131 °C in a high-pressure system, HMF was obtained from tea processing waste and hazelnut shells with yields of 8.6% (82.3 mg/g) and 6.7% (66.7 mg/g), respectively. The second method involved LiCl/NaCl-doped N,N-dimethylacetamide (DMA) as an ionic solvent system for HMF production. After a 2-h reaction at 131 °C in the DMA-NaCl/[EMIM]Cl ionic solvent system, HMF was obtained from tea processing waste and hazelnut shell celluloses with yields of 5.7% (57.5 mg/g) and 3.1% (31.3 mg/g), respectively. This study contributes to the economic conversion of various food wastes into valuable chemicals, highlighting the potential of lignocellulosic biomass in sustainable chemical production.

Laboratory and pilot scale pretreatment processes were assessed for empty fruit bunch (EFB) at different morphologies using anhydrous ammonia pretreatment (AAP). The AAP was used to deconstruct the complex structure of EFB through physical and chemical reaction to promote efficient conversion of the carbohydrates to monomeric sugars. Different morphologies of EFB samples used were unpressed EFB (UE), pressed EFB (PE), pressed and shredded EFB (PES), and lastly pressed, shredded and ground EFB (PESG). The APP process was optimized using a 1.0 L laboratory scale reactor and further scaled up to a 22 L pressure vessel (AAPB). AAP-PESG contained 76.2%, and AAP-PES contained 75.5% of structural carbohydrates, showing no significant difference. AAP-UE showed the lowest glucan conversion of 28%. The optimal laboratory conditions adopted were 135 °C, 30 min, moist to dry EFB loading of 2:1, and ammonia to dry EFB loading of 1:1. Glucan conversion of AAP-PES were 87%, 80%, and 62% at 1%, 3%, and 6% glucan loadings, respectively. The AAP-PES detected acetamide concentration at 7.3 mg/g, while AAPB-PES was only at 4.4 mg/g. Chemical composition, Fourier transform infrared spectroscopy, Brunauer Emmett Teller surface area, and scanning electron microscopy supported the assessment of AAP and AAPB processes.

Efficacies of plant metabolites are known to be dependent on their extraction methods. Yields and compositions of phytoconstituents in the extract were evaluated following supercritical fluid extraction (SFE) of Vitex agnus-castus leaves, static extraction times (SET) for 30 min, subsequently dynamic extraction time (DET) for 30 min (condition A) and SET for 0 min followed by DET for 60 min (condition B). The extract exposed to condition B gave an extraction yield of 0.169 g compared to 0.115 g for condition A. High-performance liquid chromatography analysis revealed compounds including cinnamic acid, kaempferol, ferulic acid, rutin, and caffeic acid, in high concentrations in the extract exposed to condition B. Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Enterococcus faecalis, and Candida albicans were more affected by the condition B with 32 ± 0.1, 20 ± 0.2, 32 ± 0.2, 35 ± 0.2, and 40 ± 0.1 mm inhibition zones, respectively. Less MIC and MBC were noticed of the exposed extract to condition B than to condition A against C. albicans and bacteria. The IC₅₀ of the extract exposed to condition B was high against ovarian tumor cells. Presently the efficacy of the exposed extract to condition B for wound healing process was documented.

Rainforests, as invaluable natural resources, play a pivotal role globally, offering many ecosystem services such as recreation. This study aims to quantify the value of Brunei’s rainforest assets (specifically recreational areas and national parks) utilizing the Travel Cost Method (TCM), a prevalent approach for ascertaining the worth of natural sites. The tourism use of Brunei’s rainforests holds a high value, estimated at over $300,000 USD per square kilometer, which supports the argument for resource allocation towards their protection not only for ecological reasons but also for their recreational benefits. The authors posit that nature-based ecotourism can be a sustainable and protective mechanism for tropical rainforests. Practical recommendations for ecotourism include a minimalist approach to visitor regulation, limiting access to a small percentage of large recreational areas and national parks to protect flora and fauna, and possibly implementing entry or service fees.

The design of auditorium chairs can directly reflect the image of public spaces. At present, the development of public furniture is relatively slow compared to household and office furniture. The design of auditorium chairs on the market is severely homogenized, relying on past experience and lacking scientific guidance. In order to create a better indoor public activity environment for users, from the perspective of user needs, first of all, 21 user needs for auditorium chairs were obtained through semi-structured interviews. Then, the Kano model was used to determine the attribute positioning of each demand. Finally, the FAST method was used to transform user demands into functions, assisting in the design optimization of hall chairs and promoting the future development of public furniture. The results indicate that the design of auditorium chairs must meet safety and stability, and the comfort and rechargeability of the seats are the most important needs of users. In the future, the functional design of auditorium chairs also needs to consider intelligent applications. The study applies a Kano-FAST integration method to the design innovation of auditorium chairs, providing data support for the development of furniture enterprise auditorium chairs and promoting product upgrading and optimization.

Bonsai is a kind of classical art in China and Japan. The traditional method of bonsai shaping of miniature trees is technical and usually requires experienced horticulturists to successfully carry out the process. In order to let ordinary people feel the fun of bonsai shaping, this paper proposes a fast bonsai shaping method, i.e., by use of a plastic guiding mold with customized shape, which is processed by fused deposition 3D printing technology. The tree seedling is bundled onto the mold, and the shape of the mold guides the growth of the tree seedling, thus achieving the purpose of bonsai shaping. In order to further improve the bending properties of the bonsai guiding mold, this paper investigated the main 3D printing parameters of ABS filament. The results showed that with the decrease of printing speed, the increase of extrusion temperature, and the increase of hot bed temperature, the bending strength and elastic modulus of ABS specimens increased, and the bending properties was enhanced; the optimal printing speed was 50 mm/s, the extrusion temperature was 230 °C, and the hot bed temperature was 80 °C. The mechanical properties of the bonsai guiding mold manufactured based on the optimal process parameters were better, the print quality was higher, and it had high practical value.

The effects of the antioxidant, butylated hydroxytoluene (BHT), and the metal chelator, ethylenediaminetetraacetic acid (EDTA) in combination with cedarwood oil (CWO) were investigated for wood preservation against subterranean termites as well as two species of white-rot decay fungi and two species of brown-rot decay fungi. Vacuum pressure impregnation was used to treat wood blocks. Resistance of the treated wood test blocks was evaluated using a no-choice bioassay for termites and a soil bottle assay wood decay fungi. Eight treatments were tested: H₂O only; BHT only; EDTA only; BHT with EDTA; CWO only; CWO with EDTA; CWO with BHT; and CWO with BHT plus EDTA. For termites, the lowest percentage wood mass losses were for the EDTA, BHT, CWO, and CWO/EDTA treatments, all of which were statistically equivalent. Correspondingly, these treatments all had the highest termite mortalities at 100%. The four species of decay fungi were affected differently by the wood treatments; however, overall CWO and EDTA gave the best protection against wood mass loss. The addition of BHT did not decrease mass loss.