Volume 15 Issue 3

Statistical modeling of a screw press was established by using an experimental design based on the screw rotational speed, the pulp feed consistency, the pulp feed suspension freeness, the inlet pressure, and the counter-pressure at the discharge end. The statistical models showed that the screw press outputs for each pulp could be predicted. When including all data in a global model to predict the outputs of the press for any pulp, a global statistical model was found not to be efficient by using just the five fixed parameters. The solution to this problem was to use a multivariate analysis to include more parameters, mainly about the fiber characteristics (crowding factor, fiber length, fiber width, and fines content). By including these fiber properties, the differences between each pulp were more properly analyzed. The multivariate analysis predicted the press outsets very well in a global model by using eight parameters instead of five. The R2 values of the multivariate prediction model were all higher than 0.70 and had the goodness of prediction (Q2¬¬¬) higher than 0.60.

Sales of timber, which represent the main source of forest management income, are essential for the economic welfare of forest businesses. Planning the timber sale management faces a certain amount of uncertainty and risk in such difficult conditions of climate change. Model scenarios make preparation for potential future development possible. The aim of the study was to create a prediction model of coniferous and non-coniferous sawlogs for the area of the Central Europe. The objective of the model was to estimate the variations in the price of coniferous or non-coniferous sawlogs following a linear regression equation in the analysed time series from 2001 to 2017. The price of coniferous sawlogs was significantly affected in a negative way by the amount of incidental fellings and in a positive way by the Gross Domestic Product. The price of the non-coniferous sawlogs was significantly affected in a positive way by the GDP and the volume of non-coniferous sawlog export. These factors caused a non-elastic response of the coniferous sawlog price. The impact of these factors depends to a great extent on the wood species composition of the forests in the Slovak Republic. The model also can be set for conditions of other countries when considering their economic indicators.

Fungal decay and fire resistance properties of wood treated with nano-chitosan-TPP particles were investigated. Quaternized and non-quaternized nano-chitosan particles crosslinked with a commercial fire-retardant, tripolyphosphate, were prepared from low molecular weight chitosan (with a molecular weight of 50 to 190 kDa). Different treatments were performed on southern yellow pine wood samples via a vacuum impregnation process for both quaternized and non-quaternized nano-chitosan-TPP particles with a concentration ratio of 12% to 4.8% (nano-chitosan to TPP). Both the leached and unleached treated wood samples were exposed to brown rot (Gloeophyllum trabeum) and white rot (Trametes versicolor) fungi according to AWPA standard E10-16. The flammability test was performed with a cone calorimeter according to ASTM standard E1354-15. The heat release rate and the mass loss rate were measured. The results of the fungal tests indicated that the quaternization of the nano-chitosan particles resulted in a reduced mass loss in the pine samples when exposed to Trametes versicolor under leached conditions. Additionally, without the quaternization of the nano-chitosan particles, the mass loss in the pine samples was reduced when exposed to Gloeophyllum trabeum under unleached conditions. The production of nano-chitosan-TPP particles had a significant effect on the fire-retardant activity of the treated wood samples.

Effects of mineral-based fire retardants were investigated relative to the thermal and fire properties of medium-density fiberboard (MDF) via thermogravimetric analysis (TGA), limiting oxygen index (LOI), and thermal conductivity testing. Mineral-based chemicals containing huntite /hydromagnesite and zinc borate (ZB) were used at different concentrations. Changes in all values were observed depending on the type and concentration of chemicals. According to TGA evaluation, the residual weights in the MDF samples manufactured with mineral-based chemicals were higher than the residual weight in the control MDF sample. Limiting oxygen index testing results showed higher values for the MDF samples manufactured with mineral-based chemicals than for the control sample. The LOI values increased with the increment of chemical concentration, and the highest value was observed in group B12. The thermal conductivity trends of the MDF samples varied depending on the type and concentration of chemicals. Generally, the thermal conductivity values of the MDF samples manufactured with chemicals were found to be higher than the value of the control. These results suggested that these chemicals with various combinations should be evaluated as fire retardants for wood and wood-based panel industry.

In the wake of the global COVID-19 pandemic and the subsequent movement control order (MCO) in Malaysia, an on-line survey was undertaken involving 748 small and medium enterprises (SMEs) in the furniture industry. The main objective was to examine the impact of the pandemic and the subsequent MCO on the various business aspects of the SMEs as well as to make recommendations to the government on supportive measures for the SMEs. The survey found that although all aspects of the business were impacted, the two major concerns of the SMEs during this crisis were the financial management and the supply chain disruptions. Inevitably, it was found that most of the SMEs were operating well below capacity, which was a huge financial strain on their business viability. It was recommended that the government provide measures to help the SMEs manage their cash-flow and ease the restrictions to facilitate supply-chain commencement that is crucial to their business. The survey also revealed that most SMEs acknowledged the importance of automation and the adoption of technologies. Respondents regarded the shift towards Industry 4.0 was inevitable as a means increase their resilience when facing future uncertainties.

The enhancement of enzymatic hydrolysis is important for the biorefinery industry of lignocellulose. Changing the pH of hydrolysis is a simple and direct way to improve hydrolysis efficiencies. In this study, the enzymatic hydrolysis efficiencies of sugarcane bagasse (SCB) treated with liquid hot water (LHW) were 56.7% and 65.5% at pHs of 4.8 and 5.5, respectively. The result of cellulase adsorption on the LHW treated SCB showed that the non-productive adsorption was smaller at pH 5.5, which might tend to enhance hydrolysis. The surface hydrophobicity of lignin was larger at pH 5.5. This suggested that the hydrophobic interaction was not dominant because a strong hydrophobicity force can cause more non-productive adsorption of cellulase with lignin. At pH 5.5, the surface negative charges of lignin and cellulase increased. Therefore, the electrostatic repulsive force between lignin and cellulase increased, leading to less of the non-productive adsorption of cellulase on lignin. In addition, the cellulase desorption from the LHW treated SCB also increased at pH 5.5. This was beneficial in increasing the possibility of cellulase re-adsorption in new binding sites on cellulose and promoting enzyme hydrolysis efficiency.

The anatomical characteristics and the physical and chemical properties of wood of Quercus macdougallii Martínez are presented for the first time. Q. macdougallii Martínez is an endemic species of the Sierra Juarez of Oaxaca. The microscopic characteristics were described in preparations of typical cuts and dissociated material. The physical properties were evaluated according to the ASTM D 143-94 standard in sapwood and heartwood specimens. The measurable elements and physical properties were classified according to the mean. With the measurable elements, the paper pulp quality index was determined. In sapwood and heartwood, the basic chemical composition was determined. The wood of Q. macdougallii presented a pronounced grain, a thick texture, and a straight thread. Fibers, fibrotracheids, uniseriate, multiseriate, and aggregate rays were found. Basic density 0.55 g cm-3 in sapwood and 0.61 g cm-3 in heartwood is classified as moderately heavy and heavy, respectively. The saturation point of the fiber is classified as high. Based on its physical properties, Q. macdougallii wood can be used in the manufacture of furniture, veneer, floors, tool handles, and construction. Based on the pulp quality indices and chemical composition, this wood could be used to obtain cellulose pulp for paper.

Studies have revealed that Dioscorea hispida tubers contain a poisonous substance called alkaloid dioscorine. The method for removing alkaloid dioscorine in Dioscorea hispida is explored in this research through a soaking process. The tubers were peeled, washed, sliced, and soaked for 5 days in either 1.0 M sodium chloride (NaCl) or distilled water. The aim of this study was to firstly identify the amount of toxic dioscorine remaining after soaking for 5 days, and then determine the best solution for removing dioscorine compounds in the tubers that were obtained from a tropical area in Peninsular Malaysia. The liquid chromatography electrospray ionization mass spectrometric (LC-ESI-MS) systems were used to identify the presence of alkaloid dioscorine compounds within Dioscorea hispida tubers. The analysis showed that no dioscorine compounds were present in day 5 for samples soaked in the NaCl solution. However, the relative abundance in the distilled water solution at day 5 was 281000, indicating a 95% decrease of the relative abundance value of the dioscorine compounds. This work aimed to determine the minimum days needed to remove the poisonous element before Dioscorea hispida tubers could be used for food consumption or for any other applications.

The aim of this work was to detect sounds providing evidence of the creation of drying defects and to correlate such data with drying quality. A further goal was to establish sound wave thresholds of ideal drying through the drying process by using an acoustic emission (AE) monitoring method. Thus, it is projected to decrease long drying times and also drying costs by reaching to ideal drying schedules. In this study, commercially preferred sessile oak and oriental beech structural lumbers were dried with three different schedules in a conventional kiln. The lumbers were “listened to” with AE sensors while drying according to the first two schedules, which were called protective and severe, respectively. AE events of the drying experiments were compared with ambient conditions and drying classes according to the standard of European Drying Group. The third drying schedule was optimized based on the AE peaks and applied. The results showed that ideal drying times were reduced up to 19% relative to the protective drying schedule, while obtaining the same drying quality for both species.

A novel process based on low-energy mechanical pulp and deep eutectic solvents (DESs) was evaluated with the goal of producing fibers suitable for papermaking. Ideally, these fibers could be produced at much lower costs, especially when applied to an existing paper mill equipped with a thermomechanical pulp (TMP) production line that was threatened with shutdown due to the decreasing demand for wood-containing paper grades. The efficiency of DES delignification in Teflon-coated autoclaves and in a specially designed non-standard flow extractor was evaluated. All tested DESs had choline chloride ([Ch]Cl) as the hydrogen bond acceptor. Lactic acid, oxalic acid, malic acid, or urea acted as hydrogen bond donors. The temperatures and times of the delignification tests were varied. Chemical analysis of the pulp samples revealed that DESs containing lactic acid, oxalic acid, or urea decreased the lignin content by approximately 50%. The DES delignification based on [Ch]Cl and urea exhibited good hemicellulose retention while DES systems based on organic acids resulted in varying hemicellulose losses. The [Ch]Cl / urea mixture did not appear to be corrosive to stainless steel, which was another advantage of this DES system.