Volume 16 Issue 2

The tension test parallel-to-fiber in anisotropic materials, such as bamboo, is one of the most important tests because it makes it possible to evaluate mechanical properties used in calculations for different types of stresses. For this type of test there are standards that apply to wood in general, others to bamboo, and other more specific ones that apply to bamboo Guadua angustifolia Kunth. These rules suggest the use of dog bone test specimens. When performing such tests parallel to the fiber direction, failures are observed in undesired zones. This document characterizes and analyzes the possible types of failures. It also evidences the difficulties presented and quantifies them finding that, for 59 failed test pieces, only 18.6% had failures within the desired zones, while the other 81.4% had failures within undesired zones in the tension test parallel to the fiber. Finally, it can be concluded that there are gaps in the rules that influence the variation of the results obtained by different authors. The dog bone test specimens are not recommended for tension tests parallel to the Guadua fiber. Rather, utilization of straight specimens is recommended with a calculated clamping height and the standard equation and protected clamping area.

This work investigated how thermal modification affects the shear strength of welded joints under different climatic conditions. The order of the thermal modification, before or after the welding, was investigated for its effect on the shear strength of the welded wood. Two groups of thermally modified specimens were prepared in a laboratory kiln under controlled conditions, one thermally modified before welding and the other after welding of the specimens. The shear strength of the specimens were measured at four different moisture contents of 10%, 12%, 16%, and 18%, and the results for the two different approaches were compared. Moreover, observations of the X-ray computed tomography scanning and digital microscopy were used to study the density profile and the structural details of the welded joints. The results showed that thermal treatment of the wood either before or after welding had a negative influence on the shear strength, and the modes of failure of the joints in mechanical tests were in most cases brittle. In the weld interface of the wood modified before welding, a rigid material similar to charcoal was produced as a result of the further degradation of wood by welding pressure and frictional motion. Welding of wood before thermal modification, however, yielded thicker and more densified joints with less susceptibility to higher moisture variations than the joints obtained by welding the thermally modified wood.

In this study, a superhydrophobic wood surface was prepared with amino-functionalized nano-silica (SiO2) particles, epoxy resin (EP) of different curing times, and octadecyltrichlorosilane (OTS). The micro-nano structures of the wood samples were represented by scanning electron microscopy (SEM), while the hydrophobicity and durability of the hydrophobic effect was shown by the contact angle (CA) tests. The results indicated that the optimal curing time of EP was 4 h, such that the wood surface exhibited promising superhydrophobicity with a static CA of 155.4° and a sliding angle (SA) of 3.9°. The different curing time of EP had a remarkable influence on the roughness and the pore structure type of superhydrophobic wood surface. In terms of the Cassie-Baxter theory, the increase of CA on the wood surface was ascribed to the presence of secondary air pores and rough structure in the solid-liquid interface. The obtained wood surface not only possessed excellent adhesion stability and anti-aging properties, but also a resistance to acidic solutions, organic solvents, and mechanical abrasion.

Response surface methodology (RSM) was employed to optimize the extraction conditions of phenolic and antioxidant compounds from matcha green tea (Camellia sinensis) using central composite design (CCD). The desirability function was used to find the optimum extraction conditions. The highest polyphenol and antioxidant content yield were reached at a temperature of 80 °C, an extraction time of 20 min, a liquid-to-solid ratio of 100 mL/g, and a desirability value of 0.948. The experimental values for total phenolics under the optimum extraction conditions were 317.62 ± 3.45 mg GAE/g and 29.21 ± 0.38 mg RE/g for the total flavonoids. The antioxidant activity (AA) was evaluated using 2,2 diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), which showed radical scavenging activities at 88.28 ± 0.14% and 90.02 ± 0.14%, respectively. The high performance liquid chromatography (HPLC) analysis at the optimum condition revealed 14 compounds. Among the analyzed compounds, matcha green tea extract (MGTE) had the highest content of epigallocatechin gallate (EGCG) with 95.48 mg/g, followed by epicatechin gallate (ECG) at 74.48 mg/g, and catechin at 28.94 mg/g. The results suggested that the optimized parameters of heat-assisted extraction provide an ideal green extraction method for the extraction of the high polyphenol and antioxidant content in matcha green tea.

Water safety and security has become a great problem in recent years, as the shortage of water resources in most countries is becoming an increasingly serious issue. Therefore, searching for new water sources or treating contaminated water has become a major requirement to covering the shortage of fresh water. The current study evaluated the impact of Trichoderma asperellum on the physicochemical characterization of agricultural run-off (AR) compared with groundwater (GW). Chemical oxygen demand (COD), biological oxygen demand (BOD5), ammonia, total nitrogen (TN), and total dissolved salts (TDS) of AR were higher than that of GW with 90, 90.2, 91.9, 78, and 61.6%, respectively. The addition of T. asperellum to AR caused the COD, BOD5, ammonia, TN, and TDS to decrease 47.2, 39.2, 16.2, 12.9, and 4.8%, respectively. Contents of metals in AR or GW were decreased by T. asperellum. Microbial analysis of soil irrigated by AR in contrast to irrigated by GW showed the presence of a high number of bacteria (32 × 106 CFU), actinomycetes (18 × 104 CFU), and fungi (13 × 104 CFU). Trifolium alexandrinum growth and its antioxidant enzymes activities (catalase, superoxide dismutase, and ascorbate peroxidase) were enhanced by AR inoculated by T. asperellum compared with un-inoculated AR or GW.

To improve the ability to recycle polyethylene (PE)-coated paperboard, one solution may be to use nanofibrillated cellulose (NFC) to generate a layer that should weaken when wet that leads to a clean separation between the polymer film and the pulp fibers. This NFC layer has the potential to improve the package’s oxygen and grease barrier properties, but this system has not been explored in the literature. In this study, papers coated with zero, 2, and 4 g/m2 of NFC were laminated with a PE film under a range of pressing temperatures and times at a constant pressing pressure. A model was developed to predict fiber recovery given the air permeability of the paper, pressing time, polymer temperature, and paper void volume. The recyclability or fiber recovery was evaluated in addition to the adhesive strength. Samples with the NFC layer had much improved fiber recovery because the NFC layer gives a good separation during the recycling operation. The model predictions were compared to the experiments.

Ground support provided by crane mats ensures the safety of workers and integrity of heavy-duty machines. Analytical evaluation of timber mats is necessary to advance the development of engineering standards associated with wood-based as well as other types of mats. The goal of this study was to mechanically evaluate bending stiffness and strength of timber 8-inch and 12-inch deep mixed oak bolt-laminated timber mats. The 8-inch-deep specimen dimensions were 24 inches wide and 12 feet long, while 12-inch-deep specimens were 24 inches wide and 18 feet long. Twenty-eight specimens of each depth were flexurally tested over a 17:1 span to depth ratio. The modulus of elasticity along with the parametric and non-parametric design strength values are presented herein. The characterization of timber crane mats by analyzing their mechanical properties provides a starting point for producers and users to understand the performance and applications of their product. Further research will allow investigation of alternative materials, sizes, and structural designs.

Contemporary furniture marketing platforms that are based on furniture exhibitions, retail malls, and galleries were severely disrupted by the global COVID-19 pandemic. Therefore, this study was conducted to evaluate the extent to which digital marketing tools were adopted by furniture manufacturers in Malaysia. The effectiveness of digital marketing tools was assessed as an alternative furniture marketing medium by means of a questionnaire distributed to various furniture suppliers. The results of the questionnaire indicated that the onset on the COVID-19 pandemic accelerated the adoption of digital marketing among furniture manufacturers of all sizes. Larger manufacturers had the financial means to make greater investments into digital marketing to utilize it compared to the small and medium-sized enterprises (SMEs). Digital marketing by website, email, and social media were the most common mediums used by furniture manufacturers. As for social media applications, Facebook, Twitter, and Instagram were the common platforms used by furniture manufacturers. Although some furniture manufacturers were familiar with digital marketing, many were not using it effectively due to a lack of skilled workers with the ability to manage such digital marketing tools. Limited financial capital, especially among the SMEs, also made it difficult to enable the adoption of digital marketing.

The vibrational frequency method was used to measure the elastic modulus of laminated veneer lumber (LVL), and the feasibility of using Weibull distribution to analyze the elastic modulus data of LVL was considered. Samples were randomly selected as test pieces at the factory. The sponge support structure was used to realize the free beam state, and the modal test results verified the accuracy of realizing the free beam. Under transient excitation, the elastic modulus of the specimen was obtained by testing the first-order bending frequency. The Weibull distribution fitting test, Weibull distribution K-S test, and normal distribution K-S test were used for the test data. The probability of LVL elastic modulus was calculated under a given value. The results showed that the LVL elastic modulus did not obey the two-parameter Weibull distribution (Eu=0). The LVL elastic modulus fit to the three-parameter Weibull distribution (Eu) was greater than half of the minimum test value and the normal distribution. When 9 GPa and 8 GPa were used as the setting values of Eu, the calculated probability value was relatively stable. At this time, Eu was 81% and 92% of the minimum elastic modulus 9.815 GPa. Therefore, it was recommended to use 80% to 90% of the minimum value of the measured data as the setting value of the position parameter Eu. The three-parameter Weibull distribution and the normal distribution calculated LVL elastic modulus have the same probability under the given value.

It was proposed that pre-hydrolysing tule (Typha domingensis Pers) would make it possible to produce handsheets with strength-related properties similar to those of conventional commercial paper, in addition to valorizable hemicelluloses. The hypothesis was tested with a biorefining scheme involving autohydrolysis. Conditions were optimized to maximize the extraction of hemicelluloses while preserving glucan integrity. The autohydrolysis at a liquid to solid ratio of 13 at 141 °C for 45 min (optimized conditions) provided a commercially useful liquor containing primarily tule hemicelluloses. The autohydrolysis of tule before alkaline extraction made it possible to obtain a valuable liquid phase comprising between 23.3% and 71.6% of all hemicelluloses in the raw material. The gross heating value for the hydrolyzed tule was increased (1.6% to 7.9 %) with respect the raw material. The solid phase was subjected to soda–anthraquinone pulping. The yield, ethanol extractives, kappa number, viscosity, glucan, xylan, Klason lignin, soluble lignins, as well as the tensile index were evaluated. Tule was found to be amenable to industrial processing for the production of quality cellulose derivatives. Autohydrolysis provided valorizable liquor in addition to solid that yielded soda–anthraquinone pulp having properties similar to those obtained in its absence, but using milder operating conditions.