Volume 19 Issue 2

To address the imbalance in the supply of grass resources caused by seasonality and regional factors, it is crucial to efficiently store and transport alfalfa. Exploring suitable grass feed processing techniques contributes to the stable transportation of grass blocks and long-term storage of nutritional components. The Central Composite Design response surface design was used to design experiments, with moisture content and compressive force as the test factors. Based on the experimental results, it was found that lower moisture content and a certain compressive force were beneficial for the stability, high density, and protein storage of alfalfa blocks. The microscopic examination of alfalfa particles revealed that a certain moisture content (15%) facilitates the formation of solid bridges between particles, leading to more stable alfalfa blocks. The final optimized process parameters were moisture content of 14.3% and compressive force of 34.8 kN. Under these conditions, the density of the molded alfalfa block was 1001 kg/m³, with R-CP at 96.96%, R-EE at 67.23%, and R-CF at 114.13%.

Inulinase is an inulin degrading enzyme that exhibits versatility in disparate bioresource and bioprocess industries. In this study, invertase-free exoinulinase was initially produced from Glutamicibacter arilaitensis strain ALA4 using diversified inexpensive substrates under solid state fermentation. Strain ALA4 revealed maximum production of inulinase using goat dung as quintessential feedstock. Inulinase activity of strain ALA4 was further optimized by one-factor-at-a-time method, followed by response surface methodology, which showed enhanced inulinase activity of 4678.34±34.67 U/g at 96 h using goat dung medium of pH 8.0 with 100% of moisture content. Furthermore, crude inulinase was not only thermo-alkali stable but also exhibited tolerance towards varied metal ions, organic solvents, surfactants, and inhibitors with satisfactory residual activities. Additionally, fructose produced due to the hydrolysis of inulin present in goat dung was analyzed by osazone and HPTLC tests which further confirmed exoinulinase nature of enzyme. In a nutshell, the study evidenced the first report on invertase-free exoinulinase production from G. arilaitensis using goat dung as proficient feedstock and demonstrated its quiescent applications in bioprocessing industries in future.

Natural fibers along with glass fibers were used as the reinforcement of an epoxy matrix for the betterment of mechanical and wear applications. The combination of overall wt% up to 20 resulted in 23.8 MPa of tensile strength compared to 15.5 MPa for untreated fibers. The wt% of areca fiber (AF) (20 wt%)/glass fibers (GF) (20 wt%) with 5% alkali treatment yielded a maximum tensile strength up to 62.6% in comparison to untreated fiber at lowest percentage of 10 wt%. The increase in flexural strength with alkali treatment was observed from 20 to 50 wt% hybrid fiber incorporation. The alkali treated fibers, untreated fiber combinations achieved 33.8% and 26.8% improvement with impact properties. A decrease in the wear loss was shown with the increase in wt% of hybrid fiber incorporation from 20 to 40 wt%. The interfacial adhesion of fiber with matrix created a pressure absorbing zone that was positively influenced with applying higher loads. The frictional rate was highly increasing with increase in hybrid fiber wt% and also with higher loads applied. The SEM results for treated 20 wt% AF+20 wt% GF with hybrid fiber incorporation observed better results due to improved adhesion of fiber with matrix phase.

Lactic acid (LA), citric acid (CA), and glycerol (G) are renewable and environmentally friendly chemicals that could improve the qualities of short-rotation teak (SRT) woods. This study investigated the effect of thermal and chemical modification using 20% aqueous solutions (w/w) of LA, CA, and G and their mixtures in the same composition on physical and mechanical properties of SRT teak wood. The impregnation process was initiated by vacuum process for 1 h and pressure (12.2 bar) for 2 h, followed by thermal (150 °C) treatment for 6 h on the SRT wood samples after being removed from the vacuum-pressure tube. Retention (R), weight percent gain (WPG), density (D), anti-swelling efficiency (ASE), leachability (WL), modulus of elasticity (MOE), and modulus of rupture (MOR) were measured. FTIR spectrometry and SEM analyses were performed. The wood impregnated with a mixture of 10% LA + 10% CA provided the highest ASE values of 50.1%, and the lowest leaching resistance of 1.54%. Based on wood strengths (MOE and MOR) and physical properties, as well as supported by FTIR and SEM analysis, the use of 10% LA + 10% CA is the most prospective as an impregnant formula for SRT wood modification of this research.

Nanofibrillated cellulose (NFC) and its combined usage with cationic starch and a cationic copolymer of acrylamide were studied in relation to the properties of paper. Independent pulp treatments using additives separately included 0%, 5%, 10%, and 15% refined long fiber pulp, 3 and 6% NFC, 0.75 and 1.5% cationic starch and 0.07% and 0.15% cationic polyacrylamide and combined treatments. Handsheets were made of the above treatments, and finally their optical and microscopic properties were evaluated. Increasing the NFC content to 6% increased the brightness and yellowness of the white liner by 13% and 21%, respectively. The liner opacity was also reduced by 1%. Additionally, increasing NFC by 6% compared to imported long fibers, the brightness and yellowness of the white liner increased 5.44% and 6.3%, respectively. The liner opacity was also reduced by 1%. A 1.5% cationic starch addition to NFC increased the brightness of the white liner by 4.4%, its whiteness increased 1.5%, and its yellowness increased 2.1%. The opacity of the liner was also reduced by 7.1%. The use of NFC and cationic starch can improve the optical properties of the white liner, while imported long fibers may be problematic.

Carbon quantum dots (CQDs) with good water solubility and fluorescence properties were successfully synthesized from Chenopodium quinoa Willd. straw, a biomass by-product, by a one-step carbonization method. Structural characterization of the fabricated carbon quantum dots by Fourier transform infrared spectroscopy (FT-IR) demonstrated the presence of a large number of functional groups on the surface of the carbon quantum dots, which gives them good water solubility. The synthesized carbon quantum dots were characterized optically by ultraviolet-visible absorption spectroscopy (UV-Vis), photoluminescence spectroscopy (PL), and other analytical tools. Results indicate the addition of alkali metal ions gave a different degree of promotion of fluorescence intensity (Li⁺＞Cs⁺＞K⁺＞Na⁺＞Rb⁺), and according to this feature carbon quantum dots can be used as a new means of alkali metal ion detection.

The aim of the study was to synthesize silver nanoparticles (AgNPs) from Alpinia purpurata leaves and evaluate their cytotoxic, antimicrobial, antibiofilm, dye degradation, and larvicidal potentials. The synthesized AgNPs were characterized using ultraviolet-visible spectroscopy, Fourier transform infrared, and high-resolution transmission electron microscopy, which confirmed AgNPs synthesis and revealed nanoparticle size (10 to 30 nm) and the presence of silver. Cytotoxicity tests showed IC₅₀ values of 4.59 ± 0.6 µg/mL in A549 cells and 3.48 ± 0.4 µg/mL in PA1 cells, inducing apoptosis and DNA fragmentation. Flow cytometry revealed cell cycle arrest at G0-G1 phase. AgNPs exhibited significant antimicrobial activity, with maximum inhibition zones against K. pneumoniae (23 ± 2 mm) and F. oxysporum (17 ± 2 mm), and minimum inhibitory concentration (MIC) values ranging from 12.5 ± 0.25 to 75 ± 2.5 µg/mL. They also reduced bacterial and fungal biomass and showed antibiofilm effects. Photocatalytic activity degraded methylene blue dye by 88.4 ± 1.4% in 60 minutes. Larvicidal activity resulted in 100% mortality of A. aegypti larvae after 48 hours exposure to AgNPs (10 mg/L), additionally reducing chemical oxygen demand (55.1 ± 2.1% to 63.8 ± 1.5%) and microbial load in wastewater (2.5 to 10 ppm).

In this study, the finite element method (FEM) was used to determine the effect of the optimal angle of the thread and double thread application among self-tapping screw (STS) design information on the improvement of the withdrawal capacity of the connection. It was modeled by reflecting the design information of an Italian STS distributed in the domestic wooden building market, and the stress distribution of the connections was compared according to the change in the thread angle. A cross laminated timber (CLT) composed of five layers was modeled as a member. The STS modeling was centered on the threaded area, and two threaded angles were applied: 90° and 95°. Additionally, the stress changes were compared when double threads located in the middle of the thread pitch in the screw pitch were applied to improve the withdrawal capacity of the connection. The domestic STSs were manufactured using four materials and two shapes. The finite element analysis and strength performance tests of the STS types indicated that the material properties, angle of the screw thread, and shape of the screw thread affect the Korean CLT withdrawal capacity.

Untreated wood has excellent environmental benefits due to the lack of treatments; however, its durability needs to be great enough to provide a sufficient service life to not override the environmental benefits. The aim of this study was to investigate some wood properties of untreated, unfinished Norway spruce and their influence on moisture dynamics and crack development under natural exposure. Three field-trials were carried out, all under natural exposure during various exposure times. The specimens differed in their exposure direction (north/south), composition (heartwood/ sapwood), density, and thickness. Moisture measurements were carried out either by use of sensors or weighing the specimens, while the crack formation was measured using digital calipers. Generally, high-density spruce exhibited more rapid moisture fluctuations than low-density; this agreed well with the increased crack development observed in the field-trials. More cracks were observed for specimens containing sapwood rather than heartwood. This was likely caused by an increase in moisture uptake, generating greater moisture gradients. The results also showed that the crack tendency was greater in specimens within the high-density group placed facing south, which is likely due to an increase in moisture variation, and perhaps also faster UV-deterioration. No clear correlation between crack tendency and thickness was found.

This study aimed to test the utility of ammonium persulfate (APS) oxidised nanofibrillated cellulose (NFC) as an additive for chitosan- and alginate-based biopolymer films that could eventually be used as paper coatings for food packaging applications. Sodium alginate and chitosan were used as the base for the films. Various concentrations of APS oxidised NFC ranging from 0% to 10% were used as a reinforcing agent, resulting in six combinations of either alginate-NFC or chitosan-NFC composite films. Biofilms were tested for their mechanical properties (tensile strength and strain), grease barrier properties, air permeability, water vapour permeability, and degradation in the soil. Overall, when using the ammonium persulfate oxidation pretreatment method, the best performance of the films was estimated with the addition of 2.5% NFC.