Volume 18 Issue 2

The anatomical characteristics of the culms and culm bases of ssanggol- and min-bamboo, which are mutated species of Phyllostachys bambusoides, were investigated using optical microscopy to understand the material properties. The vascular bundles in the culms and culm bases of both species were type I. There were a few abnormal vascular bundles in the culm base of ssanggol-bamboo, and more developed fiber bundles in the inner part of min-bamboo. A wavy surface was observed in the pith cavity of the ssanggol-bamboo culms. In the inner part, the vascular bundles of min-bamboo culms showed a regular diagonal arrangement, whereas those of ssanggol-bamboo were distributed randomly. In the culm base, ssanggol-bamboo had a significantly higher proportion of parenchyma and vessels, whereas min-bamboo had a higher fiber proportion. Both species had comparable proportions of cells in their culms. The vascular bundle density of min-bamboo was significantly higher than that of ssanggol-bamboo, whereas ssanggol-bamboo showed a significantly larger vessel diameter than min-bamboo. Ssanggol-bamboo had a shorter parenchyma cell length and larger parenchyma cell width than min-bamboo, whereas the min-bamboo culm showed a longer fiber length than that of ssanggol-bamboo. Furthermore, in the culm base, the fibers of ssanggol-bamboo were longer.

The voluminous generation of distilled spirits lees (DSL) in China presents a challenge for proper disposal and potential environmental pollution. In an effort to address this issue, this study aimed to find a resourceful solution for DSL utilization. The application of incinerated rice husk ash as a mortar supplementary material in cement provides an innovative solution for the disposal of DSL. Five samples of distilled spirits lees ash (DSLA) were produced using both muffle furnace (MF) and fluidized bed (FB) combustion at different temperatures. The properties of DSLA were characterized through measurements of specific surface area and observations using scanning electron microscopy (SEM). Mortar specimens were prepared by replacing 10% of cement with DSLA, and strength tests were conducted. The SEM results revealed the crisscross mesh structures in the DSLA samples. Additionally, the findings indicated a strong connection between the specific surface areas and the micromorphology. In this work, all DSLA samples, except for the one produced in FB at 800 °C, could improve compressive and flexural strengths in the prepared mortar specimens and were suitable for employment as cement additives.

The influence of hydrothermal treatment (HTT) on the hemicellulose, i.e. glucomannan/galactoglucomannan (GM/GGM) and arabinoglucurono-xylan (AGX) in Japanese cedar was examined using mild temperatures (95 °C and 120 °C) for its kiln drying. Based on infrared spectra, only a slight change due to HTT was observed in the hemicellulose chemical structure. The quantitative changes of the major chemical components including lignin, cellulose, and hemicellulose also exhibited slight differences among samples. However, the molecular chain-length composition of GM/GGM and AGX in the cell walls decreased clearly with HTT, as well as with an increase in temperature. Also, it was found that the strength of the interaction between cellulose and hemicellulose molecules such as GM/GGM and AGX in cell walls decreased depending on the increase in HTT temperature. These results showed that the polymeric structure of GM/GGM and AGX was degraded by hydrolysis at 95 °C of HTT and proceeded further at 120 °C of HTT.

Urea-formaldehyde is one of the commonly used resin types in the particleboard industry. In this study, the effect of nanofibrillated cellulose (NFC) and titanium dioxide (TiO₂) addition in the formulation of the urea formaldehyde resin on the physical, mechanical, and morphological properties of particleboard samples was investigated. The NFC (0.5% and 1%) and TiO₂ (0.5%, 1%, and 2%) were added to the 10% adhesive formulation. Two different pressure times, 4 and 8 min, were applied during the production of samples. Subsequently, the water absorption (WA), thickness swelling (TS), internal bonding strength (IB), modulus of rupture (MOR), modulus of elasticity (MOE), scanning electron microscopy (SEM), and statistical analysis of test samples were determined. The thickness swelling values ranged from 19.9% to 34.9% and WA values were from 74.50% to 110.6%. However, the maximum MOR, MOE, and IB values were 22.2 MPa, 2570 MPa, and 1.1 MPa, respectively.

Fiberboards from scrap denim were fabricated using two different resins, melamine urea formaldehyde (MUF) and polymeric methylene diphenyl diisocyanate (pMDI). Resin content and MUF-pMDI weight ratio were studied. Physical and mechanical tests determined the modulus of elasticity (MOE), modulus of rupture (MOR), internal bond (IB), thickness swell (TS), and water absorption (WA). The resin content had significant impact on all properties. The MOE and IB were affected by the MUF-pMDI ratio. With 17 wt% more pMDI resin portion in the core layer of the denim boards, the IB for the denim fiberboard with a resin content of 15% was enhanced by 306%, while by 205% for the resin content of 25%. The increase in pMDI portion in the core layer of the boards improved both TS and WA of the scrap denim fiberboard. Effective bulk modulus elastography (EBME) was used to measure the acoustic reflection for the estimation of the strength properties of the denim fiberboard. The modulus results from EBME were correlated to the MOR, MOE, and IB of the denim fiberboard. A high correlation was found between the modulus from EBME and IB (R² > 0.98). EBME can be a great technique to evaluate the bulk modulus distribution of the composites.

Self-bonding bamboo particleboards were prepared via hot pressing of bamboo residue fermented by lactic acid bacteria. An orthogonal experiment was designed to investigate the effects of three factors (type of lactic acid bacteria used for fermentation, moisture content (MC) of the fermented residue, and hot-pressing temperature) on the resulting self-bonding particleboards. The bending strength and internal bonding strength of the prepared self-bonding particleboards were tested. Fracture characterization was performed on the cross-section of the prepared self-bonding particleboards after bending breakage. The hot-pressing temperature, moisture content (MC), and type of lactic acid bacteria of the fermented residue had a significant effect on the mechanical strength of self-bonding particleboards, and with increased hot-pressing temperature, the strength of self-bonding particleboards increased. Analysis of the cross-sectional morphology and porosity confirmed the significant effect of hot-pressing temperature on the density distribution of self-bonding particleboards. The self-bonding particleboard produced at the hot-pressing temperature of 180 °C, MC of 30%, and that used Lactobacillus plantarum as a fermentation strain showed the best overall performance and reached Chinese standard requirements for common particleboards.

Various natural sound-absorbing materials such as rice by-products, coir fiber, date palm fiber, peanut husks, hardwood cross-sections, and forest by-products have been introduced to replace petroleum-based sound-absorbing materials in previous studies, and their sound-absorbing performance was significant. This study investigated the sound-absorbing performance of pure coffee grounds as an eco-friendly sound-absorbing material. After inserting coffee grounds into cylindrical holders with lengths of 20, 30, and 40 mm, the density of the coffee grounds was adjusted from 0.2 to 0.5 g/cm³. Then, the sound absorption coefficients were measured by an impedance tube. As the thickness and density increased, the sound absorption coefficient at low frequencies improved. However, the sound absorption coefficient at high frequencies decreased. The optimal noise reduction coefficient (NRC) of coffee grounds investigated in this study was 0.61 at a density of 0.3 g/cm³ and thickness of 50 mm. This result shows a sound-absorbing performance that is comparable to other natural sound-absorbing materials. This study concludes that coffee grounds have high use-value as an eco-friendly sound-absorbing material.

The effect of duration of load testing on flexural properties of structural insulated panels was investigated herein. Structural insulated panels were manufactured by a member of the Structural Insulated Panel Association (SIPA) in accordance with International Code Council-Evaluation Service Report 4689. Two panel depths 16.5 cm and 31.1 cm (6.5 in. and 12.25 in.) were tested in short duration 1/3-point bending per American Society for Testing and Materials standards. All structural insulated panels had joints or discontinuities in the foam layer in a location that was subject to shear stress during the bending tests. Failure mode for all panels was horizontal shear within the foam layer. Within each panel depth, no statistically significant differences were detected between the maximum load values before and after creep testing. This finding indicates that the creep test loading was not detrimental to the strength of the structural insulated panels. While the results were not deemed to be statistically different for the Δy_max (midspan deflection at P_max) for the 31.1 cm depth class, they were statistically different from the 16.5 cm depth class. Overall, it appeared that there was minimal effect of the creep test loading on Δy_max of the SIPs.

The applicability of cotton-bleached soda pulp (C-BSP) was investigated as a raw material for manufacturing cationic nano-fibrillated cellulose (NFC) via quaternization of anionic NFC using glycidyl-trimethyl-ammonium chloride (GMA). The anionic NFC was prepared by beating and micro-grinding C-BSP, and quaternization was performed post treatment to induce a charge reversal in anionic NFC. The characteristics of cationic NFC manufactured using C-BSP and hardwood-bleached kraft pulp (Hw-BKP) as a control were analyzed. Relatively higher mechanical energy was required to prepare anionic NFC from C-BSP than that from Hw-BKP. Fourier transform infrared and zeta potential analyses results showed that quaternization by GMA post treatment electrostatically induced charge reversal in anionic NFC. However, GMA did not affect the fiber width and viscosity of the cationic NFCs. It was found that cationic NFC could be manufactured via quaternization of anionic NFC manufactured from C-BSP using less GMA than that for Hw-BKP.

Pitaya is a tropical fruit from a newly cultivated plant in Turkey that has increasing economic value. In this study, its seed properties were investigated. Pitaya fruit samples used in the research were obtained from local producers in the Gazipaşa/Antalya region. The dry matter, protein, oil, and ash content of H. polyrhizus and H. undatus pitaya seeds were 89.7% to 89.1%, 19.8% to 17.5%, 22.8% to 24.0%, and 2.8% to 4.09%, respectively. The oil and protein contents of the seeds were very high. The total phenolic content, α-tocopherol content, γ-tocopherol content, free radical scavenging activity, and induction time of H. polyrhizus and H. undatus pitaya seeds were 12.8 to 11.9 mg GAE/g dry sample, 3.67 to 2.75 g/kg oil, 1.29, 1.64 g/kg oil, 46.9% to 51.5%, and 5.37 to 5.07 h, respectively. Seeds contained significant amounts of phenolic compounds and tocopherols, which play an important role in increasing oxidative stability. The percent inhibition of DPPH indicated that pitaya seeds may be evaluated as an antioxidant source. Unsaturated fatty acids were high in seed oils of both pitaya species. Linoleic acid, a polyunsaturated fatty acid, was dominant in both pitaya species. The chemical properties of the seeds were similar to those of species grown in tropical countries. Future studies should investigate other pitaya species grown in Turkey.