Veneer Production Research Articles

A methodology for computing the thermal balance and energy consumption of autoclaves during steaming of wood

ABSTRACT A methodology for computing the thermal balance and energy consumption of autoclaves during steaming of wood has been presented. With the help of own non-stationary model, the durations of all stages of steaming regimes of beech prisms intended for veneer production with cross- section dimensions of 0.3 × 0.3 m, initial temperature 0 °C, and moisture content 0.4, 0.6, and 0.8 kg·kg−1 were determined at maximum operating temperature in the autoclave equal to 130 °C. With the determined prism steaming durations, using a proposed steady-state model, the total energy required to carry out the entire steaming process in an autoclave with an internal diameter of 2.4 m, a cylinder length of 9.0 m and a degree of filling with prisms 30%, 40% and 50% and also the required for each of the individual components of the thermal balance are calculated. It was found that the total energy consumption of the autoclave increases from 82 to 113 kWh·m−3 when the moisture content of the prisms increases from 0.4 to 0.8 kg·kg−1 at autoclave filling degree of 40%. The methodology can be applied to compute thermal balances of different autoclaves during steaming of wood to any desired final temperature required for their mechanical processing.

Production and technical performance of scrimber composite manufactured from industrial low-value wood for structural applications

Development of scrimber composites and other engineered wood products from low-value wood and wood waste provides an effective opportunity to preserve natural resources, minimize waste, and innovate the production of higher-performance, environment-friendly construction materials. In this study, peeler cores, which are the center of poplar logs remaining after the peeling process in the veneer production, were utilized to develop scrimber composites. This study investigated the effects of different resins, including phenol-formaldehyde (PF) and urea formaldehyde (UF), as well as hydrothermal treatments at various temperatures (60 °C and 130 °C), on the physical and mechanical properties of the scrimber composites. Chemical changes in wood components and morphological changes in wood cell walls resulting from hydrothermal treatment were analyzed using Fourier transform infrared spectroscopy and scanning electron microscopy. To clarify how resin type and hydrothermal treatment affect structural performance, several physical and mechanical properties of scrimber composites, including thickness swelling, water absorption, internal bond strength, bending modulus of elasticity, and modulus of rupture, were measured. The test results revealed that hydrothermally treated wood scrims at 130 °C, when bonded with PF resin, produced scrimber composites with superior structural performance.

The Potential Alternative Antibacterial Activity of Falcata (Falcataria Falcata) Leaf Methanolic Extract against Staphylococcus Aureus and Escherichia Coli

The Potential Alternative Antibacterial Activity Of Falcata (Falcataria falcata) Leaf Methanolic Extract Against Staphylococcus aureus And Escherichia coli  Laliefe B. Arnan; Katherine Joy S. Escueta; Nor Rashida P. Rashid; Elyca M. Tacbobo; Queenie Rose M. Tinoy  Degree: Bachelor of Science in Pharmacy  Thesis Adviser: Junnin Gay L. Garay, RPh, CPh, MS Pharm Falcata is a plant that can be found in the Philippines and is used for the production of wood veneer and plywood. While in Indonesia, it is used as traditional remedy for malaria (Budiarti et al. 2020). They belong to the Fabaceae family, a family known for having great antibacterial effects (Gamo et al. 2015). This study used a percolation extraction method and the percentage yield is calculated to determine the yield from the falcata extract. Disc diffusion method is used for susceptibility testing and determining the zone of inhibition for the different groups. The CLSI guidelines for Staphylococcus aureus and Escherichia coli will be used to determine the antibacterial effect of the extract, in terms of resistance, intermediate, and susceptible results. From the results, the percentage yield of the methanolic crude leaf extract of Falcataria falcata is 2.67%. Leaves from the Falcataria falcata plant were extracted and tested against bacteria. The extracts showed promise in inhibiting the growth of Staphylococcus aureus and Escherichia coli bacteria, with 75% concentration as being more effective. However, these bacteria showed some resistance to all extract concentrations: S. aureus (90% - resistant, 75% - intermediate, 50% - resistant, 25% - resistant); E. coli (90% - resistant, 75% - resistant, 50% - resistant, 25% - resistant). Further study is needed to determine the exact antibacterial properties of the plant.

Influence of selected factors on the energy consumption of frozen logs subjected to thermal treatment in veneer production

ABSTRACT This study puts forward an approach for calculating the specific energy consumption and its components required for heating of frozen logs for veneer production, depending on the logs’ initial temperature and moisture content. The approach is based on the use of two personal models: unsteady model of the temperature distribution along the radius of frozen logs during their thermal treatment and stationary model of the energy consumption of logs subjected to such treatment as a function of its four multifactorial components. The influence of all combinations between five values of the initial temperature of frozen logs from −1 oC to −40 oC and three values of their moisture content from 0.4 kg·kg−1 –0.8 kg·kg−1 on the specific energy required to heat and placticize beech logs with a diameter of 0.4 m at operating temperature of the steaming or boiling medium of 80 oC was investigated. The obtained results show that this energy changes in the range from 46 kWh·m−3 (at −1 oC and 0.4 kg·kg−1) to 114 kWh·m−3 (at −40 oC and 0.8 kg·kg−1) The approach could be applied to calculate the energy and its components required for carrying out of the thermal treatment of various frozen capillary-porous materials.

Commodity risk assessment of maple veneer sheets from Canada.

The European Commission requested the EFSA Panel on Plant Health to deliver a risk assessment on the likelihood of pest freedom from Union quarantine pests and pests subject to measures adopted pursuant to Article 30 of Regulation (EU) No 2016/2031 for the maple veneer sheets manufactured according to the process set out by Canada, with emphasis on the freedom from Davidsoniella virescens and Phytophthora ramorum (non-EU isolates). The assessment was conducted for veneer sheets of up to 0.7 mm and up to 6 mm thickness, taking into account the different phases in the veneer production in a systems approach. Some of those phases, taken alone, including the heat treatment of logs in a water bath, the cutting into thin veneer sheets and the final high heat drying of veneer sheets are expected to be effective against some of the pests, without uncertainties, making the system approach fully effective. The panel considers that no insects would survive cutting of logs into thin veneer sheets of 0.7 mm and that Xylella fastidiosa will not survive the temperatures in the water bath and final drying of veneers. The degree of pest freedom for the different groups of organisms is generally very high with slightly lower degree of pest freedom for veneer sheets of 6 mm thickness because of lower temperatures reached in the final drying of veneer sheets compared to thinner sheets. P. ramorum is not expected to survive the high heat drying of thin veneer sheets, but it may survive the lower temperatures inside thicker veneer sheets. The Expert Knowledge Elicitation (EKE) indicated, with 95% certainty, that between 9989 and 10,000 veneer sheets (thickness 6 mm) per 10,000 will be free from living P. ramorum. For D. virescens, the EKE indicated, with 95% certainty, that between 9984 and 10,000 veneer sheets (0.7 mm) per 10,000 and that between 9954 and 10,000 veneer sheets (6 mm) per 10,000 will be free from living inoculum. For other relevant groups of pests, the greatest likelihood of pest presence was observed for wood decay fungi. The EKE indicated, with 95% certainty, that between 9967 and 10,000 veneer sheets (0.7 mm) per 10,000 and that between 9911 and 10,000 veneer sheets (6 mm) per 10,000 will be free from living wood decay fungi.

An engineering approach for calculating the energy required for defrosting and subsequent heating of frozen wood during thermal treatment

ABSTRACT An approach for calculating the energy required for defrosting and subsequent heating of frozen wood during thermal treatment in the production of veneer has been presented. Using two own unsteady models the duration of regimes for steaming of prisms in an autoclave and for boiling of logs in a pit, and also the average mass temperature of the prisms and logs and the energy accumulated by them at the end of heat carrier introduction in these regimes was determined. The obtained values of average temperature were introduced in third own model for engineering calculation of the energy considered in the approach. Computer simulations were carried out for beech prisms with a cross section of 0.4 × 0.4 m and beech logs with a diameter of 0.4 m at an initial wood temperature of −10°C, −20°C, and −30°C and moisture content of 0.6 kg·kg−1. The operating temperature of the prism steaming regimes was equal to 130°C, and that of the log boiling regimes was 80°C. The approach can be applied using Excel for computing the energy and its components needed for defrosting and heating of different frozen capillary-porous materials subjected to multiple types of thermal treatment.

A Simulation Study of the Heat Balance of Concrete Pits During Boiling of Non-Frozen Logs

This paper presents an approach for computing the heat balance of boiling pits during the plasticizing of non-frozen logs intended for the production of peeled veneer. With the help of our non-stationary model, the heating times of beech logs with a diameter of 0.4 m, an initial temperature of 10°C, and a moisture content of 0.6 kg∙kg-1 were determined at water temperatures in the pit equal to 70, 80, and 90°C. Using the determined logs’ boiling durations and the mentioned approach, the change in the total energy required to carry out the entire boiling process and that required for each of the individual components of the heat balance was calculated. Computer simulations were conducted for a concrete pit with overall dimensions of 8.0 × 2.6 x 2.5 m, a working volume of 20 m3, and a degree of filling with logs equal to 45, 60, and 75%. It was found that the increase in the water temperature from 70 to 90°C causes an increase in the total specific energy, as well as in the energy for the heating of the logs themselves, the construction, and the water of the pit. At the same time, the energy required to cover the heat losses of the pit decreases and the energy for heating the metal heater/radiator itself does not change. A decrease in the degree of filling of the pit with logs from 75 to 45% causes an increase in both the total energy and all its components except the energy for heating the logs, which remains unchanged.

New particleboards for food-packaging from poplar peeling by-products using a circular economy approach

New particleboards for food-packaging from poplar peeling by-products using a circular economy approach

An approach for computing the thermal balance and energy consumption of concrete pits during boiling of frozed logs for veneer production

ABSTRACT An approach for computing the thermal balance and energy consumption of pits during boiling of frozed logs intended for veneer production has been presented. With the help of our own non-stationary model, the boiling times of beech logs with a diameter of 0.4 m, initial temperature of −10°C, and moisture content of 0.6 kg·kg−1 were determined at water temperatures in the pit equal to 70°C, 80°C and 90°C. Using the determined logs’ boiling durations and the mentioned approach, the change in energy required for the entire boiling process and that for each of the components of the thermal balance was calculated. Computer simulations were performed for concrete pit with a volume of 20 m3 and a degree of filling with logs 45%, 60%, and 75%. It was found that the total energy consumption of the pit increases from 169 to 205 kWh·m−3 when the temperature of the boiling water increases from 70°C to 90°C at a pit filling level of 75%. The approach can be applied to compute thermal balances of concrete pits during boiling of frozed and non-frozed logs to any desired final average mass temperature required for the mechanical processing of the plasticized logs.

Mathematical description of the operating temperature in regimes for autoclave steaming and subsequent air conditioning of wood

ABSTRACT A mathematical description of the operating temperature of each of the five constituent stages of regimes for autoclave steaming and subsequent air conditioning of wood has been proposed. This description has been included in the boundary conditions of two coupled own non-stationary temperature-energy models of the autoclave steaming process of wooden prisms intended for veneer production. Using these models, calculation of the durations of the initial part and of the whole regimes for steaming of beech prisms have been carried out. The variables were an initial wood temperature of 0 and –20 °C, moisture content of 0.4, 0.6, and 0.8 kg·kg−1, and cross-section dimensions of the prisms 0.3 × 0.3 m and 0.4 × 0.4 m; steaming autoclave with a diameter of 2.4 m, length of 10.6 m, and loading level of 40, 50, and 60% at limited thermal power of 500 kW suplied to the autoclave. The simulations carried out using Visual Fortran showed a good agreement of the proposed mathematical description with many previously obtained experimental results and confirmed the possibility of its being applied in the boundary conditions of various non-stationary models of autoclave treatment processes (steaming, impregnation, desired property modification) of wood and other materials.

Site quality impacts tree form, heartwood content and veneer production of plantation-grown Pinus patula

Abstract Plantation forest species were introduced into South Africa due to limited availability of native forests for wood-derived products. Currently, the Mexican pine species, Pinus patula, is the most widely planted softwood species in the country. To study the effect of growth environment on wood and processing properties for the species, sample plots were established in a 20-year rotation covering a wide range of soil geologies and altitudes in Mpumalanga, South Africa. Temperature and seasonal rainfall were also determined for the sample plots. Randomly selected sample trees were harvested from the plots and processed at a plywood plant to determine veneer recovery and quality. Trees grown on sites composed of granite soils, with higher annual maximum temperatures and less rainfall, found in the Highveld region, displayed superior tree size, slenderness, and volume growth, compared to trees grown on dolomite and shale soils common to the Lowveld region. Veneer derived from Lowveld trees had more splits which were largely related to defects. Larger trees also had a greater percentage volumetric heartwood and a smaller live crown, compared to smaller trees. Highveld trees had greater net veneer recovery and produced better quality veneer than trees grown on the Lowveld. In the Mpumalanga forestry region, strong co-relatedness exists between soil geology, altitude, and climate. Although tree form and wood properties were found to differ with varying soil geology and altitude, these differences were primarily related to climate rather than soil properties. These findings highlight the pitfalls associated with neglecting either climate or soil properties when analysing site-specific growing conditions on tree growth and form.

Matching method for mutated veneer sheet images using gray-level co-occurrence matrix features

This paper studies the tracking of wooden veneer sheets by matching their respective wet and dry colour images. The tracking of veneer sheets has proved to be a challenging task due to random mutations during processing in terms of color changes, the emergence of defects, and, occasionally, lost pieces of the veneer surface. The proposed matching procedure involves image segmentation with five different sizes, followed by segment-wise extraction of Gray Level Co-occurrence Matrix (GLCM) textural feature arrays, and their similarity comparisons respectively. A voting mechanism is introduced that allocates the correct match based on the majority. An optional shifting procedure is applied to match candidates with missing areas. The method is demonstrated and benchmarked using a real-world dataset sourced from the industry, comprising 2579 high-quality images of spruce veneer pairs obtained from peeling and drying. In comparison to earlier studies that employed randomized 50 pair sampling on the same dataset, our approach yields a matching accuracy of 99.41%, outperforming the previously reported 84.93%. These findings have relevance for researchers in wood image analytics and carry practical implications for large-scale, automated veneer production facilities seeking innovative ways to optimize their raw material usage.

Computing the Thermal Efficiency of Autoclaves during Steaming of Frozen Prisms for Veneer Production at Changing Operational Conditions

A methodology for the computation of the thermal energy efficiency of modes for the heat treatment of frozen wooden prisms in an autoclave with saturated water vapor at changing operational conditions has been proposed. The methodology includes computer simulations with two own-coupled unsteady models: one to calculate the 2D temperature distribution in the cross-section of prismatic wood materials during their heat treatment, and the second to determine the heat balance of industrial autoclaves for such wood treatment. Simulations were carried out in order to determine the duration, energy consumption, and thermal efficiency of different modes, caused by changed operational conditions, for the autoclave steaming of frozen beech prisms with industrial parameters in the absence and presence of dispatcher intervention. The influence of nine combinations between the time of dispatcher intervention and the degree of reduction of the constant maximum temperature from the 130 °C of the basic mode on the thermal efficiency of the autoclave was investigated. The results show that all studied dispatching interventions cause an increase in both the duration and the thermal efficiency of the modes. This efficiency in the modes at changing operational conditions has values between 68.7% and 74.6%, while the efficiency in the basic steaming mode is equal to 68.0%.

Design of Decorative Wooden Wall Panels from Sliced Pedunculate Slavonian Oak (Quercus robur L.) from Veneer Production Residue

The growing awareness of nature conservation encourages producers, engineers, and designers to contribute to the rational and innovative use of raw materials. Sustainable development is imperative, symbolizing the balance between meeting the needs of the present generations without compromising the needs of future ones. The aim of this paper is to investigate the production process of cut veneer of Pedunculate Slavonian oak (Quercus robur L.) and which parts of the logs are lost or thrown in the production of cut veneer, to analyze the increase in the use of veneers that currently represent residue in processing, and to propose directions of designing a new product from the analyzed residue—decorative wall panels. The research was conducted in the company Spačva Ltd. in Vinkovci, Vukovar-Srijem County, Croatia, in 2021/2022. The findings emphasize that the vast majority of unused veneers, considered technologically unacceptable in the production process, can be decoratively and visually desirable due to their natural appearance in the design of a new product. By analyzing and applying the design principles and elements, natural phenomena were applied to the veneers that represent the basic motif of the new decorative wall panels. The initial solutions of the decorative wall coverings made of veneer with a natural appearance and the solution from other wood residues from production are shown. The results of this study have potentially far-reaching implications for wood product manufacturers and demonstrate the importance of applying design in wood technology to reduce residue, demonstrating that residue from standard production can be designed into an innovative, sustainable product that reduces environmental damage.

Chemical Composition of Industrial Wood Waste and the Possibility of its Management

Organic wood waste (sawdust, shavings, pieces of wood and bark), is widely used as a secondary raw material and, after composting, for soil fertilisation and substrate production in agriculture, horticulture, forestry, urban landscaping and rehabilitation of degraded land. However, problematic to process is wood waste that is very dirty with soil. They have limited calorific value and cannot be used in the R10 recovery process of land treatment benefiting agriculture or improving the environment. However, the morphological composition of these wastes indicates that they have good properties and can be used for agricultural use and for the reclamation of degraded land. The research involved wood waste with the code 03 01 99 (other unspecified waste from wood processing and the production of panels and furniture) generated during the preparation of deciduous tree logs for the veneer production process, and ashes from the burning of wood waste generated in the veneer production factory. The aim of the study was to assess the chemical composition of these wastes and the possibility of their agricultural use. In the samples of wood waste and ashes there was determined: pH; chlorines content; conductivity; hydrolytic acidity; content of micro and macroelements and heavy metals. The morphological composition of the waste is dominated by sawdust, with a smaller share of shavings, bark and earth parts, and a small addition of pieces of wood of various sizes. It is rich in easily bioavailble as well as total macroelements and is not contaminated with heavy metals. Analyzed wood waste has deacidifying properties, high sorption and buffering capacity. Studies have shown that the wood waste produced at the veneer factory, can be used as an organic fertiliser, a component of other organic fertilisers, for soil mulching, horticultural substrate and soil and land reclamation.The ash obtained from burning wood is strongly alkaline and rich in alkaline cations, mainly Ca, Mg and K. It is not contaminated with heavy metals. The ash can be used for soil deacidification and fertilization, especially for soil reclamation. The waste from the heap can be used as an organic fertilizer, a component of other organic fertilizers, for mulching soils and as a gardening substrate. However, the possibilities for non-agricultural (e.g.: for the production of pallet, particle board) use are limited due to the high proportion of earthy parts.

Impact of Facility Location on the Financial Performance of Integrated and Distributed LVL Production in Subtropical Eastern Australia

In subtropical eastern Australia, the declining availability of traditional, large hardwood native forest logs has motivated hardwood sawmills to explore potentially utilising small logs in the manufacture of veneer-based engineered wood products (EWPs), such as laminated veneer lumber (LVL). An aspatial mathematical model that maximises net present value (NPV) over a 30-year project life has been applied to estimate the financial performance of LVL manufacture in this region. Of particular interest was how facility location affected financial performance, and whether distributed production of veneer (close to the log resource) and LVL (distant from the log resource) may be more profitable than integrated production under some circumstances. While integrated production of veneer and LVL near the resource maximised NPV, distributed production was found to be more profitable than integrated production in situations where the LVL manufacturing facility had to be located relatively far from the resource. Nevertheless, the level of value-adding and processing scale had a greater impact on financial performance than facility location. The analysis also highlighted that log procurement strategy substantially affected financial performance. Encouragingly for forest growers and wood processors, utilising large volumes of small diameter logs, was important for maximisation of NPV of larger-scale LVL facilities.

The artistic properties of rosewood (Dalbergia latifolia Roxb.) as a reference for the development of decorative veneers and synthetic vinyl.

Research on the basic characteristics of sonokeling wood ( Dalbergia latifolia Roxb.) has not been carried out widely. These properties include texture, pattern and color. This research aims to study and recognize these characteristics as a consideration of potential utilization of sonokeling wood to be developed widely. One simple technique in diversifying beauty of this wood was by drying treatment and visual photography technology combination. The research results showed that sonokeling wood had a very clear difference between heartwood and sapwood, and the growth rings are clearly visible. The wood texture is rather rough, especially at sapwood. The texture is rather smooth and shiny on heartwood. The pattern is very clear with beautiful black lines. The pattern is an embodiment of anatomical, chemical characteristics and radial section appearance of sawn wood. In production of decorative veneer, pattern will appear maximal in veneer slicing technique. Average color value ( E ) of sapwood = 63.54 (brown-yellowish brown) while heartwood = 32.28 (dark brown-blackish brown). Sonokeling wood is worthy to be widely developed considering of its beautiful patterns and colors, especially for product diversification of decorative veneers and synthetic vinyl. So that sonokeling wood become one of popular wood, especially in Java Island.

Computing the duration of regimes for autoclave steaming of frozen wooden prisms under variable operating conditions in veneer production

ABSTRACT An approach for calculation of the duration of regimes for intensive autoclave steaming of frozen wooden prisms in cases of dispatching interferences into the operating temperatures has been suggested. The approach is based on the use of two coupled personal mathematical models: a 2D non-linear model of the unsteady distribution of the temperature in frozen and non-frozen prismatic wood materials subjected to steaming and a model of the non-stationary thermal balance of autoclaves for steaming wood materials. Using the suggested approach, calculation of the duration of regimes for defrosting and heating of beech prisms have been carried out. The variables were an initial wood temperature of −20°C, moisture content of 0.6 kg·kg−1, and cross-section dimensions of the prisms 0.4 × 0.4 m; steaming autoclave with a diameter of 2. 4 m, length of 9.0 m, and loading level of 50% for the cases of lowering by the dispatcher the maximum temperature of the basic steaming regime from 130°C to 120, 110, and 100°C in the 3rd, 7th, and 11th hour of these regimes. The approach can be applied for developing optimized energy-efficient regimes for autoclave steaming of frozen wood materials with desired duration set by the dispatcher.

Stress distribution in veneers under lamination and simultaneously bending: an experimental and numerical investigation

ABSTRACT Laminated veneer products (LVPs) are veneers glued together into a predetermined shape. Experimental and numerical investigations were performed under lamination and simultaneously bending of veneer laminate to study the stress distribution in the laminate. Laminates of different thicknesses were made of peeled veneers of European beech. The veneers were coated with adhesive, inserted in a mould which had the shape of a semicircle, and finally pressed at 20°C to a laminate. Two Teflon-polymer films including sensors for measurement of the contact pressure were placed on both sides of the laminate to measure the local contact pressure (contact stress) between the laminate and the mould. At the beginning of the bending process, the contact stresses were locally distributed over the laminate in a similar pattern as in a three-point bending; after the laminate was further bent, the stress distribution rearranged to be as in four-point bending. In the end of the moulding, the local contact stresses increased over the entire laminate and reached a ‘peak-value’ over bent area in the middle part of the mould. A finite-element model was created to study the bending process. Regarding the overall development of the contact stress variations, the experimental and the numerical results agreed.

Bonding Acetylated Veneer for Engineered Wood Products—A Review

The purpose of this review is to put previous research findings on acetylated wood and the fabrication of veneer-based products in a common context. The first research on wood acetylation was already conducted in the 1920s using wood meal, whereas relevant research on veneer acetylation was published nearly two decades later, during the 1940s. In the years that followed, a great deal of research has been done on both solid wood and composite acetylation. Developments in the 1990s and early 2000s resulted in the creation of commercial products. Nowadays, wood is becoming increasingly popular in construction. Therefore, high-performance materials with high dimensional stability and durability are required. Veneers are thereby of particular relevance because of their propensity to absorb chemicals into even tough-to-treat wood species. However, acetylation alters the bonding properties of wood, which is important for the manufacture of engineered veneer products, especially in load-bearing construction. A large amount of research is now being conducted on the acetylation of veneer, and acetylated veneer products are anticipated in the near future. This study covers the fundamentals of bonding but focuses specifically on veneer acetylation and its fabrication to engineered veneer-based products. The influencing factors of acetylation on bonding are also discussed.