Dry Pine Wood Research Articles

Establishment of patterns in the thermal modification of dry pine wood

One of the methods of ensuring the durability of dry wood during operation is its thermal modification, which inhibits the life processes of the fungus of the Ceratostomaceae family and leads to a change in its structure and properties. Therefore, the object of research was thermally modified dry pine wood affected by a fungus of the Ceratostomaceae family. Physicochemical studies of changes in the structure of thermally modified dry pine wood showed that the samples have absorption spectra that are characterized by fluctuations of the glucopyranose ring of cellulose and are an indicator of the beginning of destructive processes. At the same time, the data of thermogravimetric analysis show the processes of water loss and decomposition of hemicellulose, cellulose, and lignin, and burning of coke residue. Bending and compressive strength of thermally modified dry pine wood shows that as the wood dries, the strength limit decreases depending on the degree of fungus damage. Namely, with an area of biological damage within 10 %, the strength limit is reduced by more than 1.2 times when modified at 200 °С/3 hours, by more than 1.9 times at 200 °С/6 hours. With an increase in the degree of fungal damage to 30÷50 %, the strength limit decreases by more than 1.6 times when modified at 200 °С/3 hours, by more than 2.1 at 200 °С/6 hours. And when affected by a fungus in the range of 80÷100 %, the wood becomes softer, more plastic, while the bending strength is reduced by 1.7 times, and the compressive strength by 1.16 times. Thermal modification of dry pine wood at 200 °С for 3 hours reduces the level of water absorption by more than 1.5 times, and for 6 hours ‒ by more than 1.7 times. The practical importance is that the results of determining changes in the structure and properties of thermally modified dry pine wood make it possible to establish the scope and conditions of its application

Effect of Viroc Conduct under Compression on the Mechanical Characteristics of Sustainable Materials

To meet energy-saving requirements, in recent years, Saudi Arabia’s construction industry has focused on researching the use of naturally available resources as raw materials. This study looks at the behavior of Viroc, specifically using pinewood and its compression properties in eco-friendly concrete. The study demonstrates the feasibility of adding pinewood to concrete and provides a theoretical basis for the promotion of dry pinewood particles and Portland cement composite materials. The Viroc specimens used in the study are 18 mm long, 12 mm wide, and 12 mm deep. The mechanical properties of the specimens were tested and compared by using a universal testing machine (UTM) and the Ansys software program 2022. The test results show that Viroc can increase the compression strength and modulus of the construction material as well as increase its brittleness and toughness (mechanical properties). The results show that it is feasible to incorporate wood and cement, resulting in a new type of Viroc composite material in an eco-friendly environment.

Establishing regularities in the application of dry pine wood

The issue related to using dry wood products for building structures is to ensure their stability and durability during operation while it is necessary to take into consideration changes in their properties and structure. Therefore, the object of this study was pine wood struck by drying out. It is proved that in the process of drying, wood porosity decreases, and, accordingly, the tensile strength, depending on the degree of damage by the fungus. Specifically, with the area of damage in the range of 30‒50 %, the strength limit decreases by more than 1.3 times, and if the fungus affects the area within 80÷100 %, the wood becomes softer, more ductile while the strength limit is reduced by 1.1 times. Based on the results of physicochemical studies, discrepancies in the IR spectra were identified, indicating structural changes in the constituent components of wood. There is a decrease or absence of intensities of absorption bands of some functional groups and the appearance or intensification of others. Wood samples, in determining the highest calorific value, show a difference in values, which is explained by structural changes in wood components caused by biological processes. Thermogravimetric analysis data indicate complete burnout of dry pine wood. However, for wood with tree stands not weakened by drying, the coke residue burns out at a higher temperature. Wood with blue pigmentation affected by microorganisms has significant differences in the heating area of 400÷700 °C. The nature of coke burnout allows us to make assumptions about the different qualitative and quantitative composition of the coke residue, which is formed due to structural changes. The practical significance is the fact that the results of determining the properties and structure of dry wood make it possible to establish the operating conditions for articles and building structures

Modeling of thermal conductivity of reed products

The present work researches processes of heat transfer by samples of mats manufactured from reed. Due to the unique properties of the reed, such as medium density, low thermal conductivity, relatively high weather resistance, high chemical resistance, possibility to produce parts on-site, cost-effectiveness and others, reed products are widely used in building construction despite the high rate of development of new technologies. The mechanisms of heat insulation in the result of energy transfer through the material are established, which makes it possible to influence this process. It is proven, that the mechanisms are conditioned upon the increased porosity of the material. Thus, decreasing volume weight results in decreasing thermal conductivity, and vice versa. The simulation of the heat transfer process with the flameproof coating is carried out, the dependencies of the thermophysical coefficients on the temperature are determined. Based on the obtained dependencies, the coefficient of thermal conductivity for the products made of dry pine wood is calculated and makes 0.056 W / (m · K). Features of slowing down the process of heat transfer to material made of wood wool and glue binding agent with the formation of pores were studied. This is explained by the fact that there is no movement of air in large pores, accompanied by heat transfer. Thus, there are grounds to argue for the possibility of directed regulation of the processes of the formation of thermal insulation products using the reeds characterized by voids in the stems.

Typological structure and productivity of pine forests of the Mountain Crimea

The study of the features of the territorial distribution, productivity and typological structure of natural pine stands in the Mountain Crimea was conducted. Crimean pine plantations dominate by the area here. The most productive and long-lived stands are C l-Скр under the conditions of dry sudubrava Ci. Taxational characteristics of Crimean pine plantations in different high-altitude zones reflect the peculiarities of high-altitude dynamics of their age composition. The lower belt is dominated by plants of small height and with a small trunk diameter. The stands of the upper belt have the most significant taxation characteristics. According to the level of living state, the stands of Crimean pine of the lower belt are mostly characterized by an unsatisfactory assessment. This is due not only to the negative anthropogenic impact, but also to the more severe action of limiting factors in the regional territory of natural growth of Crimean pine on the southern macroslope of the Main ridge of the Crimean mountains. Natural stands of common pine form forests in the edaphotopes of dry pinewood Bi, dry sudubrava Ci and fresh sudubrava C2. Under the conditions of dry sudubrava Ci there is an increase in the productive capacity of common pine stands. The level of use of the forest typological potential of a pine stand depends on its age. The ratio of age groups characterizes the pine stands as cyclo-multiplc-agcd. The fullness of stands of common pine varies within the range of 0.3-0.9, the average is 0.6. The most common planrings have the fullness of 0.4 and 0.5. The structure of the typological macrocomplex of stands of Stankevich pine is represented in a greater degree by communities of dry sudubrava Ci. Unfavorable abiotic factors have a direct impact on the composition of stands of Stankevich pine, the age structure of which is characterized by a predominance of young and middle-aged trees and a noticeable decrease in the number of ripening and ripe stands and a very small representation of high-aged plantations. The relative increase in the number of trees at the age of 200 240 years is evidence that in the past the conditions for the growth and renewal of stands of Stankevich pine in the Mountain Crimea were more favorable.

Heat impact and soil colors beneath hearths in northern Sweden

The archaeological remains of Sami hearths in boreal and subarctic areas of northern Sweden are common finds. Greater understanding of the effects of heat on soil coloration will facilitate interpretation of the main purpose of these hearths, for example as heat sources or for cooking or other processing, and whether they were used seasonally for long or short periods of time. We therefore studied effects of heat on the coloration of natural B-horizons beneath traditional Sami hearths using three approaches: firing with dry pine wood in experimental hearths and measuring the temperature at various levels beneath the hearths; laboratory heating of B-horizon soils at different temperatures (200–900 °C) in a muffle oven and; measuring soil color changes in terms of RGB-values, and comparing the experimental results with soil profiles beneath real hearths used by nomadic Sami reindeer herders in northern Sweden. The study shows that the temperature reached beneath hearths strongly depends on the type of fuel used and the length of firing. The temperature can rise rapidly in upper layers of the soil but it takes considerable time for heat to penetrate 20 cm below the hearth surface. Our experimental firings, for 10 h on three consecutive days and for 72 consecutive hours, resulted in bowl-shaped areas of discoloration, with strong red coloration (rubification) towards the edges and dark grey/brown discoloration in the middle of the hearths in both tests. After laboratory heating, soil samples darkened during temperatures of 200–300 °C, and rubification at 250–350 °C depending on the amount of humus in the soil. The RGB analysis showed a steady increase in rubification from 300 °C, peaking at 750–800 °C. We believe that the rubification is caused mainly by transformation of iron compounds to maghemite and hematite and that the quantity of hematite is determined by temperature and not by time.Excavations of ancient hearths also revealed examples of bowl-shaped discoloration in B-horizons deeper than 20 cm. These discolorations had a rather uniform red tone with no dark areas. This suggests that the darker areas, probably colored by reduced iron and not by charred particles, could have been altered over time. The main conclusion is that rubification in B-horizons beneath hearths can arise after a relatively short period of firing but-bowl shaped areas of deep coloration can only arise, in boreal and subarctic areas, when hearths have been fired heavily and continuously for long periods of time, indicating winter use.

Multilayer coatings on tools for woodworking

Abstract This paper presents the results of modeling of CrCN/CrN and TiAlN/TiN multilayer coatings with a thickness of 3 μm, which consist of seven bilayers, each of the thickness of ca. 400 nm, and the thickness ratio of bilayers as 1:1 for both coatings, their deposition on the HS6-5-2 steel substrate using the cathodic arc evaporation method and the measurements of their mechanical properties. The mechanical properties of monolayer coatings, which are contained in the multilayer coatings were also examined. The coatings were investigated concerning the EDS hardness and adhesion. The coefficient of friction and the wear rate of the coatings were also measured. Further research includes the determination of the durability of tools for woodworking with wear resistant coatings. The coatings tested, both the multilayers and their components, are characterized by a good adhesion being not less than 80 N. The lowest wear rate is characterized by the CrCN/CrN multilayer coating (8.5 × 10 −7 mm 3 N −1 m −1 ), the TiAlN/TiN coating has a rate being 10 times higher. Among the tested coatings TiN coating shows the lowest coefficient of friction (0.4) but the wear rate is not the lowest. It is ca. 7 × 10 −6 mm 3 N −1 m −1 and is almost 5 times higher than for the CrCN coating. Industrial research of the “lifetime” of woodworking tools with wear resistant coatings was carried out in planer knives to the head. These tools with multilayer coatings exhibit more than a twofold increase in the work life of dry pine wood cutting. Both coatings show a similar increase of durability. Further sequential re-sharpening did not change significantly the lifetime of both knives.

The effect of moisture content in fibre laser cutting of pine wood

This paper reports a statistical analysis of the multiple-pass laser cutting of wet and dry pine wood with a Ytterbium fibre laser. As multiple factors affect the laser wood cutting process, finding the optimal combination of process parameters is necessary to achieve good quality and high process efficiency. Design of experiments (DOE) and statistical modelling were used in this study to investigate the significant process parameters and their interactions. A high brightness, 1 kW IPG single mode, continuous wave Ytterbium doped fibre laser was employed to cut wet and dry pine wood samples. The parameters investigated are laser power, traverse speed, focal plane position (f.p.p.), gas pressure, number of passes, direction of cut (normal or parallel to wood's tracheids) and the moisture content. The experimental results were compared against process responses defining the efficiency (i.e. kerf depth and energy consumption) and quality of the cut section (i.e. kerf width, heat affected zone—HAZ, edge surface roughness and perpendicularity). It has been found that the laser cutting process was mainly affected by the moisture content and the cut direction with respect to the wood's tracheids, followed by traverse speed, laser power and the number of passes. The effect of moisture content on energy consumption in the laser cutting process of both wet and dry wood is analysed. The wood cutting results with fibre laser are compared with those from a CO 2 laser.

Single and dual gas jet effect in Ytterbium-doped fibre laser cutting of dry pine wood

This paper presents single and dual assist gas jet effects in the single-pass laser cutting of dry pine wood. The laser wood cutting process is influenced by the assisting gas jet(s) applied. Therefore, it is important to understand their roles in the removal of fumes and combusted materials from the cutting kerf. A computational fluid dynamic model is developed to investigate the effect of single and dual gas jets in the laser wood cutting process. In order to obtain a close approximation of the actual process, a three-dimensional model was considered. Results obtained in the simulations were compared with experimental data collected from a multifactor experiment analysing the laser cutting process of dry pine wood. A high brightness, 1 kW IPG single-mode, continuous-wave Ytterbium fibre laser was employed to cut cubic wood samples parallel to the wood fibre direction. It has been found that shear stresses produced by the gas jet(s) on the kerf walls have an important correlation with the yield and cut quality.

Dual gas jet-assisted fibre laser blind cutting of dry pine wood by statistical modelling

This paper presents a statistical analysis of the performance of an Ytterbium fibre laser utilising single and dual gas jets in a single pass to blind cut dry pine wood. Cutting wood with lasers is a multi-factor process and a proper combination of the parameters involved is needed to achieve high quality and optimum process efficiency. This study employs design of experiments and statistical modelling approach to investigate the significant process parameters along with their interactions. A high brightness, 1 kW IPG single mode Ytterbium-doped fibre laser was employed to produce blind cuts on samples of dry pine wood. The experiments were performed parallel to the direction of the wood fibre. The parameters investigated include laser power, focal plane position, traverse speed, gas pressure and single and dual gas jets. Results were compared using a number of process responses which define the efficiency of the cut in terms of kerf depth, mass removal and energy consumption as well as quality of the cut section considering the heat-affected zone, kerf width and roughness of the edge of the surface. It has been found that application of an additional gas jet produced a surface finish superior to the single jet.

Statistical analysis of ytterbium-doped fibre laser cutting of dry pine wood

This paper reports a statistical analysis of the laser wood cutting process. The laser cutting of wood is a multi-factor process and correct combination of the parameters involved is needed to achieve high quality and optimum process efficiency. In this paper a design of experiments and statistical modelling approach is used to investigate the significant process parameters by consideration of parameter interactions. A high brightness, 1 kW IPG single mode ytterbium-doped fibre laser was used to cut dry pine wood samples. The investigated parameters include laser power, focal plane position, traverse speed, gas pressure, number of passes, and cutting direction. Results are compared against a number of response factors defining the process efficiency (i.e. kerf depth, mass removal, and specific energy consumption) and the cut quality (i.e. heat-affected zone, kerf width, and edge surface roughness). It is reported that the majority of these process characteristics are significantly affected by the structure of the wood under test.

Two-Phase Transport Model for the Pyrolysis Process of a Vertical Wood Cylinder, Including the Surrounding Flow Field

This paper describes a mathematical model for the pyrolysis of a small dry pine wood cylinder. The computational domain is axisymmetric and involves the heating chamber, with the wood cylinder vertically situated in the centre of the chamber. The model simulates the laminar flow around the particle and the laminar flow inside the wood/char matrix by applying a two-phase transport model where the solid wood/char matrix acts as one phase and the various gases produced from the pyrolysis process is assembled in the other phase. Convective, conductive and thermal radiation transfer modes are included in the model. A two-step pyrolysis reaction scheme is used for the modelling of the conversion from wood to tar and gas. Both the thermal conductivity and the permeability of the wood/char matrix are modelled anisotropically in order to capture the directional differences in heat and mass transport, existing in real wood. Results from simulations are compared with measurements from literature for the centre core solid temperature and the conversion from wood to char, tar and pyrolysis gas in the particle during heating. The results show very good agreement with the measured temperature profile. The simulated conversion profile shows an overall good agreement with the measurements, however with discrepancies in the early stage of the process. Besides the successful validation with the experimental data, it provides us with all the details of the distribution of the migrating pyrolysis gas and tar, the temperature, the velocity flow field and pressure in the wood/char cylinder.

Effect of Addition of Hydrated Lime to Litter on Recovery of Selected Bacteria and Poult Performance

Recently, we demonstrated that 10 or 20% (wt/vol) hydrated lime used in poultry litter significantly reduced Salmonella enteritidis survival in vitro. However, preliminary studies with day-of-hatch poults suggested that lime in excess of 5% (wt/vol) in new litter caused mild but apparent ocular and respiratory irritation and thus was not further evaluated. Presently, we evaluated the effect of lower concentrations of hydrated lime in new dry pine wood shavings (0, 0.2, 1, or 5% wt/vol) on recovery of Salmonella, Campylobacter, coliforms, total aerobic colony-forming units, and poult performance (hatch to 7 wk). Although lime did not affect body weight at 3 wk of age, at 7 wk of age turkeys from 0.2% lime-treated pens were significantly (P < 0.05) heavier (219 g/bird) than turkeys grown in control pens. Even though incorporation of lime at the selected concentrations did not reduce Campylobacter or Salmonella recovery, lime did reduce overall aerobic colony-forming units and significantly increased weight gain in this experiment, possibly through reduction of other low level pathogens not measured in this study.