Volume 17 Issue 1

With rising concern for environmental protection, the use of ozone has been increasingly studied in the pulp and paper industry. Feasible models for efficient quality prediction and process control are in high industrial demand. In this study, the reaction kinetics of delignification and viscosity during the ozone bleaching process (OBP) of low-consistency hardwood pulp (LCHP) are explored using exponential and zero-order response models, respectively. The effects of ozone dose, reaction temperature, reaction time, and pH on the changes in residual lignin content and pulp viscosity were analyzed. The corresponding kinetic parameters, such as the reaction order, rate constant (k), and activation energy (E), were also obtained. The models suggest that temperature should be one of the most significant factors affecting the effectiveness of the OBP system. The strategy to improve the OBP selectivity is based on reducing the reaction temperature while increasing the ozone concentration and pH in the reaction system.

To accurately evaluate the modulus of elasticity in static bending (MOE) of wooden components in ancient timberwork buildings under the “minimum intervention principle,” the nondestructive testing of physical and mechanical properties were conducted on larch. Using moisture content (MC), density (ρ), the stress wave propagation velocity ( ), the modulus of elasticity in dynamic bending (E_d), the rotational resistance value of the drilling needle (f_drill), and the resistance value of the feeding needle (f_feed) as the main parameters, the correlation between several parameters and MOE was firstly calculated using the Gray Relation Analysis (GRA) and ranked according to the strength of the correlation. Six combinations were selected according to the ranking, and the Gene Expression Programming algorithm (GEP) was used to build models for predicting MOE. The results showed that the correlation between several parameters and MOE was good (between 0.5 and 0.8), and the prediction model established with combination 6 was the best, which indicated that the prediction model established based on GRA-GEP algorithm had a certain feasibility and effectiveness, and the combined effect of the six parameters to evaluate the MOE of wooden components of ancient buildings was better in the field inspection.

Next-generation laminated wood composites were produced using waste poplar (Populus deltoides) veneer and polyvinyl acetate adhesive. Four experimental groups and one control group were created. Ten-layer laminated wood veneer samples were reinforced with natural rubber (Group A), linoleum (Group B), felt (Group C), and elastomeric sponge (Group D); these materials were used in the fifth adhesive layer (middle layer). The sound absorption coefficients of the control and experimental groups were tested via the impedance tube method, according to ASTM standard E1050 (2006). Attention was paid to the acoustic behavior at low frequencies (63 Hz to 250 Hz), mid frequencies (250 Hz to 2000 Hz), and high frequencies (2000 Hz to 6300 Hz). It was determined that the sound absorption coefficient of the experimental groups considerably increased. It can be suggested that the experimental groups be used as sound absorbing acoustic panels and the control group as sound reflective acoustic panels.

Effects of alkaline (kraft and soda) and organosolv pulping were evaluated relative to the structural properties of lignin isolated from coconut husk (CH) biomass. The various types of functional groups within the isolated lignin samples were characterized and compared using a variety of complementary analyses including Fourier-transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography (GPC), and high-performance liquid chromatography (HPLC). All isolated CH lignin samples contained a significant quantity of non-condensed guaiacyl-type (G) and syringyl-type (S) units but a lesser amount of p-hydroxyphenyl (H) units, as demonstrated and supported by previous research. The alkaline CH lignin produced lignin with higher molecular weight (Mw SL: 959 g mol-1 > Mw KL: 769 g mol-1) than the organosolv lignin (Mw OL: 606 g mol-1) sample, resulting in smaller fragments and a higher degree of solubility in water or other solvents. Because of significant differences in the physicochemical characteristics of the various lignin polymers, their properties and structure were improved with respect to alternative approaches in lignin-based applications.

Today, the toilet paper market offers product types with varying number of plies, providing better mechanical strength and liquid absorption. Several tissue paper perforation systems exist, and the best commonly applied is a top-cutting mechanism that includes an oblique blade, a combined oblique blade, or a simple spiral blade. The perforation efficiency must be high to have an easy sheet separation from the roll of the toilet paper, which does not always occur. Hence, consumer satisfaction can depend on the perforation performance. To study this, a laboratory perforation system was used to perforate different commercial toilet papers (in brands and number of plies) and evaluate their perforation efficiency. A finite element method (FEM) was used to simulate the curve of the progression of perforation efficiency as a function of the cut distance. The main findings were a stabilization of the perforation efficiency from a cut distance of 6 mm and a 15% increase in the cut distance for the laboratory blade to match the industrial perforation efficiency. The FEM analysis confirmed the behavior of the evolution of perforation efficiency with the increase of the cut distance.

The hydrophilic character of cellulose nanowhiskers (CNWs) coating was changed by the use of TiO2 to modify CNWs, thus preparing TiO2/CNWs coating by a two-step method. Meanwhile, the effect of the additive amount and particle size of TiO2 on the surface structure and water contact angle (WCA) of the coatings was studied. The solid contents of the suspension were characterized by Fourier infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The TiO2/CNWs coating was characterized via scanning electron microscopy (SEM) and atomic force microscopy (AFM). Moreover, their wettability by water was revealed by the contact angle analyzer. The AFM and WCA analyses showed different additive amount and particle size of TiO2 have different effects on the surface structure and the WCA of the coatings. When the additive amount of TiO2 was 0.2 wt% and the particle size of TiO2 was 30 nm, the WCA and surface roughness (Rq) of the obtained TiO2/CNWs coating reached maximum values of 86.2° and 135nm, respectively. The TiO2 was relatively evenly distributed in the coating and the addition of TiO2 increased the crystallinity of CNWs from 79.67% to 84.89%. In addition, the FTIR and XPS analyses showed that TiO2 only physically dispersed in CNWs instead of having significant chemical reaction with CNWs.

Wood is a natural material with properties that are strongly influenced by anatomical characteristics, so studies that aim to correlate properties through empirical equations in search of simplification to obtain the values of their characteristics are essential. In this context, this work aims to generate multiple regression models to estimate the properties of shrinkage and compression parallel and normal to the grain of Brazilian tropical woods as a function of the values of porosity, density, and for both properties, with porosity being obtained by mercury intrusion porosimetry. As a result, the radial (RRT) and total tangential (RTT) shrinkage could be estimated through porosity. However, it was not possible to estimate them considering only density as an independent variable. All the models that were used were able to accurately estimate the modulus of resistance and modulus of elasticity values (fc,0, Ec,0, fc,90, and Ec,90).

L-quebrachitol is a natural monomethyl ether derivative of inositol, and it is abundant in sea buckthorn leaves. In this study, the potential efficacy on hepatic glucose, lipid metabolism disorder, and damaged pathway in vitro of sea buckthorn leaf L-quebrachitol extract (SQE) and L-quebrachitol standard (QS) was evaluated. The SQE and QS exhibited good inhibitory activity on α-amylase, and the kinetic study revealed that their type of enzyme inhibition was competitive inhibition in each case. Both QS and SQE increased the glucose consumption and decreased the contents of total triglyceride (TG) and non-esterified fatty acid (NEFA) in HepG2 cells displaying insulin resistance (IR). In addition, QS and SQE attenuated the expression levels of G6Pase and enhanced the expression of PPARα. These findings suggested that QS and SQE contributed to the modulation of glucose and lipid metabolism, and they might be a promising functional food additives and pharmaceuticals against Type 2 diabetes mellitus (T2DM).

The effect of microbial activity on the deterioration of archaeological stone items is a worldwide issue, and conserving them with low-toxicity, ecologically benign and naturally biocides is a difficult undertaking. Molecular identification of the microbial communities from a deteriorated archaeological object (Ptahshepses stone statue) located from the Saqqara excavation, Giza, Egypt was recorded. Six essential oils (EOs) (black cumin, clove, geranium, lavender, lemongrass, and thyme) were tested for antimicrobial activity against six degrading fungal and bacterial species. Alternaria alternate, Aspergillus flavus, A. niger, Cladosporium halotolerans, Penicillium crustosum, and Trichoderma viride and three bacterial species, Pseudomonas protegens, P. putida, and Serratia odorifera, were isolated. Of the most effective EOs, thyme showed the highest inhibition percentage (143.4%) against Serratia odorifera, followed by P. putida (135%), and Pseudomonas protegens (131.5%). Lemongrass and clove EOs had minimum inhibitory concentrations (MICs) ranging from 0.5 µL/mL to 2 µL/mL for all isolated deteriorated fungal and bacterial species, while the lowest efficiency EOs were lavender, geranium and black cumin. It can be concluded that thyme and lemongrass EOs have a potential use for protecting the Ptahshepses stone statue from microbial deterioration.

The continuous drying of timber is attracting increasing international interest for softwood drying because of several reported advantages, e.g., improved energy efficiency and improved grade recovery. This study aimed to investigate the impact of continuous drying kiln technology on the quality of dried Queensland plantation-grown southern pine timber, compared to the current ultra-high temperature batch drying process adopted by many softwood processors. End matched boards were dried using continuous and high-temperature drying schedules. The moisture content and moisture gradient of each board was assessed in accordance with AS/NZS standard 1080.1 (2012), AS/NZS standard 2796.3 (1999), respectively, while the drying stress was assessed in accordance with AS/NZS standard 4787 (2001). The boards dried with continuous drying schedules resulted in slightly lower bow and spring values and similar cup and twist values compared to the high temperature dried boards. The moisture gradient and drying stress were significantly lower in boards using continuous drying kiln technology compared to the high temperature dried boards. This study will allow the Australian softwood industry to better understand the dried timber quality obtained using new continuous drying technology to make informed investment decisions.