Anete Meija - Academia.edu (original) (raw)

Papers by Anete Meija

Holzforschung, 2016

Thermal modification (TM) of wood has occupied a relatively narrow but stable niche as an alterna... more Thermal modification (TM) of wood has occupied a relatively narrow but stable niche as an alternative for chemical wood protection. There are different technological solutions for TM and not all details of their effects on wood tissue have been understood. The one-stage hydrothermal modification (HTM) at elevated vapour pressure essentially changes the wood’s composition and structure. In the present paper, the changes in three hardwood lignins (alder, aspen, and birch) were observed within the cell wall by means of cellular UV microspectrophotometry. The lignin absorbances in the compound middle lamella (CML) of unmodified wood are 1.7- to 2.0-fold higher than those in the fibre S2 layer. The woods were modified in the temperature range from 140 to 180°C, while in the lower temperature range (140°C/1 h), the UV absorbances are little affected. Essential changes occur in the range of 160–180°C and the UV data reflect these by absorbtion changes, while the absorbances at 278 nm rise ...

Holzforschung, 2016

The effect of thermo-hydro treatment (THT) on the properties of birch (

BioResources, 2021

Different types of wood are used to manufacture of various wood products. In direct production pr... more Different types of wood are used to manufacture of various wood products. In direct production processes, additional resources such as energy, adhesives, labor, etc. are also used. In line with sustainable environmental policies, all resources must be used more rationally, while simultaneously increasing the efficiency of the direct production processes. This research examined whether it is possible to reduce energy and labor resources in the technological process of hot pressing of birch plywood (nominal thickness 9 mm), by varying the holding time under pressure, pressure, and adhesive consumption. The Box-Behnken experimental design for a multifactor experiment was used to investigate the influence of technological parameters of plywood pressing. The highest strength in static bending both parallel and perpendicular to the plywood grain was achieved by pressing plywood with the following gluing parameters: highest pressing pressure, 3.2 MPa; minimal holding time under pressure, 9...

Rural Sustainability Research, 2021

It has been common knowledge that as the density of wood increases, the mechanical properties als... more It has been common knowledge that as the density of wood increases, the mechanical properties also improve. In turn, the density of wood depends on many factors, including the wood moisture content, location and cross-section in the trunk, the type of treatment and the parameters of technological processes. There is a great deal of research reported in the scientific literature on the effect of solid wood density on mechanical properties for different wood species as well as for structural timber. However, no research data can be found related investigation of the influence of veneer density on the properties of the birch plywood. In the present study, researching the properties of 7-ply birch plywood (thickness 9 mm), it was concluded that as the density of veneers increases, the bending properties of plywood in the direction of wood fibers (covered veneers) increases. When determining the plywood gluing quality, similar tendencies have been observed. For plywood with a lower densi...

Rural Sustainability Research, 2015

During the last decades, thermally modified wood has become an object of interest among the wood ... more During the last decades, thermally modified wood has become an object of interest among the wood scientists as an environmentally friendly material, because nowadays environmental aspects of materials have become more and more significant. Leaching is one of the processes that occurs in outdoor use. The aim of this study was to evaluate concentration of potentially hazardous substances in leachates of thermally modified pine wood. Scots pine (

Engineering for Rural Development, 2019

Bioresources, 2020

Thermally modified birch (Betula pendula Roth) veneers that had been subjected to wood treatment ... more Thermally modified birch (Betula pendula Roth) veneers that had been subjected to wood treatment technology (WTT) or thermo vacuum (TV) processes were compared in this study. After modification of veneers in the range of temperatures from 160 °C to 218 °C and times from 0.5 h to 3 h, the color, mass loss, density, tensile strength, hygroscopicity, and decay resistance against brown rot fungus Coniophora puteana were determined. Treatment regimes with the greatest mass loss were at 217 °C for 3.0 h in TV (7.8%) and 160 °C for 0.8 h in the WTT (6.7%). As expected, wood mass loss correlated well with moisture exclusion efficiency (MEE) in all relative humidity (RH) environments (r = 0.95 to 0.99). Strength loss in the WTT was considerable compared to the TV process (57% and 40%, respectively). The resistance against brown rot fungus was moderate with a mass loss of 12% to 33%. Among the investigated samples, the regime 217/3.0/TV showed the best resistance against brown rot fungus and ...

Scots pine (Pinus sylvestris L.) is the most common wood species in Latvia. It is classified as n... more Scots pine (Pinus sylvestris L.) is the most common wood species in Latvia. It is classified as not durable, therefore additional protection against microorganisms is needed prior its use outdoors. Presently Cu-containing wood preservatives are commonly used, but the biggest drawback is the poor Cu fixation, therefore raising concerns about the impact on the environment. Three types of specimens were used to carry out the experiments – untreated, Latvian originated Scots pine; Scots pine commercially treated with preservatives that belong to a group of Cu-boron-triazole (CBA) products; and Scots pine, impregnated with micronized-Cu solution using a standard full cell process. In order to make sure that all of the specimens are equal in their components, elemental analysis was performed and content of nitrogen (1.2 – 2.5 g kg-1), carbon (485.5 g kg-1), oxygen (456.0 g kg-1) and hydrogen (55.6 g kg-1) was determined. The treated specimens were leached according to the European standar...

Thermal wood modification has been intensively studied in the recent decades because of the possi... more Thermal wood modification has been intensively studied in the recent decades because of the possibility to produce wood with improved biodurability and dimensional stability without use of harmful chemicals. Beside altered physical characteristics, wood colour is changed to lighter or darker brown as a result of thermal treatment. Growth of interest in thermal wood treatment has stimulated numerous researches concerned with discoloration of thermally modified wood which is subjected to light exposure. The objective of this study was to evaluate the colour stability of thermally modified hardwood during storage in the dark where wood discolouration is not photoinduced but rather a result of oxidative ageing. Three thermally modified hardwood species – aspen (Populus tremula L.), alder (Alnus incana Moench), birch (Betula pendula Roth.), where investigated. Wood discoloration was monitored by spectrophotometrical measurements of reflectance spectra and chromaticity parameter calculati...

International Wood Products Journal

Thermo-hydro treatment (THT) of plywood produced from birch (Betula spp.) wood veneers was carrie... more Thermo-hydro treatment (THT) of plywood produced from birch (Betula spp.) wood veneers was carried out in a multi-functional pilot device manufactured by WTT (Wood Treatment Technology). The treatment was conducted in elevated water vapour pressure conditions using four different treatment regimes: 150/10, 150/50, 160/10 and 160/50 (temperature, °C/duration, min). After the treatment, the THT plywood was subjected to the following tests: biological durability, anti-swelling efficiency (ASE), bending strength (BS), Brinell hardness (HB), equilibrium moisture content (EMC) and surface contact angle determination. THT improved most of the properties of the plywood. With increasing treatment severity, the dimensional stability and the resistance to white and brown rot fungi of THT plywood were improved. The EMC of THT plywood was lower than the untreated controls, and the surface became more hydrophobic. As a drawback, losses of BS and hardness were observed.

Due to environmental concerns the use of wood materials is becoming more extensive and is causing... more Due to environmental concerns the use of wood materials is becoming more extensive and is causing wood supply shortage, therefore the use of Populus genus wood species with a short rotation period is vital. Populus genus species wood has several shortcomings it is not durable, has low density and is hygroscopic. Thermal modification is a technology that can be used to improve the situation. In this study aspen (Populus tremula L.) was thermally treated using the Wood Treatment Technology (WTT) device for 50 min at 160 -160 WTT) and poplar (Populus x canadensis Moench) was vacuum-treated (VT) 120 min at 204 (120-204 VT), 120 min/ 214 -214 VT), 180 min 217 -217 VT) and 30 min 218 (30-218 VT). Mass loss (ML), colour change, density, tensile strength along the fibres, moisture exclusion efficiency and weight loss (WL) after brown rot fungus Coniophora puteana were determined and also light microscopy images were taken. Aspen veneers showed a ML of 5.3% between 120-214 VT (6.2%) and 30-2...

Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference

Wood is the most popular building material in the world due to its universal versatility, althoug... more Wood is the most popular building material in the world due to its universal versatility, although it has disadvantages - the difficulty to apply small diameter logs in construction, hygroscopicity and anisotropic swelling and shrinking. To solve these disadvantages, plywood from wood material is produced. Plywood is a material that can solve anisotropy, but it is still biodegradable by rot and stain fungi. Thermal treatment is a methodology that improves the durability of wood. In this paper aspen (Populus tremula L.), poplar (Populus x canadensis Moench) and birch (Betula pendula Roth) were treated by steam (WTT) and vacuum (TERMOVUOTO) devices under 160°C/50 min (birch and aspen), 204°C/2 h, 214°C/2 h, 217°C/3 h, 218°C/30 min (birch and poplar). Chemical changes in treated veneers were investigated by ATR-FTIR (Attenuated Total Reflection Fourier Transform Infrared Spectroscopy) in a range 2000 cm-1 – 800 cm-1. ATR-FTIR is a non-destructive methodology, which is important during ...

Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference

Wood is the most popular building material in the world due to its universal versatility, althoug... more Wood is the most popular building material in the world due to its universal versatility, although it has disadvantages - the difficulty to apply small diameter logs in construction, hygroscopicity and anisotropic swelling and shrinking. To solve these disadvantages, plywood from wood material is produced. Plywood is a material that can solve anisotropy, but it is still biodegradable by rot and stain fungi. Thermal treatment is a methodology that improves the durability of wood. In this paper aspen (Populus tremula L.), poplar (Populus x canadensis Moench) and birch (Betula pendula Roth) were treated by steam (WTT) and vacuum (TERMOVUOTO) devices under 160°C/50 min (birch and aspen), 204°C/2 h, 214°C/2 h, 217°C/3 h, 218°C/30 min (birch and poplar). Chemical changes in treated veneers were investigated by ATR-FTIR (Attenuated Total Reflection Fourier Transform Infrared Spectroscopy) in a range 2000 cm-1 – 800 cm-1. ATR-FTIR is a non-destructive methodology, which is important during ...

Holzforschung, 2016

Thermal modification (TM) of wood has occupied a relatively narrow but stable niche as an alterna... more Thermal modification (TM) of wood has occupied a relatively narrow but stable niche as an alternative for chemical wood protection. There are different technological solutions for TM and not all details of their effects on wood tissue have been understood. The one-stage hydrothermal modification (HTM) at elevated vapour pressure essentially changes the wood’s composition and structure. In the present paper, the changes in three hardwood lignins (alder, aspen, and birch) were observed within the cell wall by means of cellular UV microspectrophotometry. The lignin absorbances in the compound middle lamella (CML) of unmodified wood are 1.7- to 2.0-fold higher than those in the fibre S2 layer. The woods were modified in the temperature range from 140 to 180°C, while in the lower temperature range (140°C/1 h), the UV absorbances are little affected. Essential changes occur in the range of 160–180°C and the UV data reflect these by absorbtion changes, while the absorbances at 278 nm rise ...

Holzforschung, 2016

The effect of thermo-hydro treatment (THT) on the properties of birch (

BioResources, 2021

Different types of wood are used to manufacture of various wood products. In direct production pr... more Different types of wood are used to manufacture of various wood products. In direct production processes, additional resources such as energy, adhesives, labor, etc. are also used. In line with sustainable environmental policies, all resources must be used more rationally, while simultaneously increasing the efficiency of the direct production processes. This research examined whether it is possible to reduce energy and labor resources in the technological process of hot pressing of birch plywood (nominal thickness 9 mm), by varying the holding time under pressure, pressure, and adhesive consumption. The Box-Behnken experimental design for a multifactor experiment was used to investigate the influence of technological parameters of plywood pressing. The highest strength in static bending both parallel and perpendicular to the plywood grain was achieved by pressing plywood with the following gluing parameters: highest pressing pressure, 3.2 MPa; minimal holding time under pressure, 9...

Rural Sustainability Research, 2021

It has been common knowledge that as the density of wood increases, the mechanical properties als... more It has been common knowledge that as the density of wood increases, the mechanical properties also improve. In turn, the density of wood depends on many factors, including the wood moisture content, location and cross-section in the trunk, the type of treatment and the parameters of technological processes. There is a great deal of research reported in the scientific literature on the effect of solid wood density on mechanical properties for different wood species as well as for structural timber. However, no research data can be found related investigation of the influence of veneer density on the properties of the birch plywood. In the present study, researching the properties of 7-ply birch plywood (thickness 9 mm), it was concluded that as the density of veneers increases, the bending properties of plywood in the direction of wood fibers (covered veneers) increases. When determining the plywood gluing quality, similar tendencies have been observed. For plywood with a lower densi...

Rural Sustainability Research, 2015

During the last decades, thermally modified wood has become an object of interest among the wood ... more During the last decades, thermally modified wood has become an object of interest among the wood scientists as an environmentally friendly material, because nowadays environmental aspects of materials have become more and more significant. Leaching is one of the processes that occurs in outdoor use. The aim of this study was to evaluate concentration of potentially hazardous substances in leachates of thermally modified pine wood. Scots pine (

Engineering for Rural Development, 2019

Bioresources, 2020

Thermally modified birch (Betula pendula Roth) veneers that had been subjected to wood treatment ... more Thermally modified birch (Betula pendula Roth) veneers that had been subjected to wood treatment technology (WTT) or thermo vacuum (TV) processes were compared in this study. After modification of veneers in the range of temperatures from 160 °C to 218 °C and times from 0.5 h to 3 h, the color, mass loss, density, tensile strength, hygroscopicity, and decay resistance against brown rot fungus Coniophora puteana were determined. Treatment regimes with the greatest mass loss were at 217 °C for 3.0 h in TV (7.8%) and 160 °C for 0.8 h in the WTT (6.7%). As expected, wood mass loss correlated well with moisture exclusion efficiency (MEE) in all relative humidity (RH) environments (r = 0.95 to 0.99). Strength loss in the WTT was considerable compared to the TV process (57% and 40%, respectively). The resistance against brown rot fungus was moderate with a mass loss of 12% to 33%. Among the investigated samples, the regime 217/3.0/TV showed the best resistance against brown rot fungus and ...

Scots pine (Pinus sylvestris L.) is the most common wood species in Latvia. It is classified as n... more Scots pine (Pinus sylvestris L.) is the most common wood species in Latvia. It is classified as not durable, therefore additional protection against microorganisms is needed prior its use outdoors. Presently Cu-containing wood preservatives are commonly used, but the biggest drawback is the poor Cu fixation, therefore raising concerns about the impact on the environment. Three types of specimens were used to carry out the experiments – untreated, Latvian originated Scots pine; Scots pine commercially treated with preservatives that belong to a group of Cu-boron-triazole (CBA) products; and Scots pine, impregnated with micronized-Cu solution using a standard full cell process. In order to make sure that all of the specimens are equal in their components, elemental analysis was performed and content of nitrogen (1.2 – 2.5 g kg-1), carbon (485.5 g kg-1), oxygen (456.0 g kg-1) and hydrogen (55.6 g kg-1) was determined. The treated specimens were leached according to the European standar...

Thermal wood modification has been intensively studied in the recent decades because of the possi... more Thermal wood modification has been intensively studied in the recent decades because of the possibility to produce wood with improved biodurability and dimensional stability without use of harmful chemicals. Beside altered physical characteristics, wood colour is changed to lighter or darker brown as a result of thermal treatment. Growth of interest in thermal wood treatment has stimulated numerous researches concerned with discoloration of thermally modified wood which is subjected to light exposure. The objective of this study was to evaluate the colour stability of thermally modified hardwood during storage in the dark where wood discolouration is not photoinduced but rather a result of oxidative ageing. Three thermally modified hardwood species – aspen (Populus tremula L.), alder (Alnus incana Moench), birch (Betula pendula Roth.), where investigated. Wood discoloration was monitored by spectrophotometrical measurements of reflectance spectra and chromaticity parameter calculati...

International Wood Products Journal

Thermo-hydro treatment (THT) of plywood produced from birch (Betula spp.) wood veneers was carrie... more Thermo-hydro treatment (THT) of plywood produced from birch (Betula spp.) wood veneers was carried out in a multi-functional pilot device manufactured by WTT (Wood Treatment Technology). The treatment was conducted in elevated water vapour pressure conditions using four different treatment regimes: 150/10, 150/50, 160/10 and 160/50 (temperature, °C/duration, min). After the treatment, the THT plywood was subjected to the following tests: biological durability, anti-swelling efficiency (ASE), bending strength (BS), Brinell hardness (HB), equilibrium moisture content (EMC) and surface contact angle determination. THT improved most of the properties of the plywood. With increasing treatment severity, the dimensional stability and the resistance to white and brown rot fungi of THT plywood were improved. The EMC of THT plywood was lower than the untreated controls, and the surface became more hydrophobic. As a drawback, losses of BS and hardness were observed.

Due to environmental concerns the use of wood materials is becoming more extensive and is causing... more Due to environmental concerns the use of wood materials is becoming more extensive and is causing wood supply shortage, therefore the use of Populus genus wood species with a short rotation period is vital. Populus genus species wood has several shortcomings it is not durable, has low density and is hygroscopic. Thermal modification is a technology that can be used to improve the situation. In this study aspen (Populus tremula L.) was thermally treated using the Wood Treatment Technology (WTT) device for 50 min at 160 -160 WTT) and poplar (Populus x canadensis Moench) was vacuum-treated (VT) 120 min at 204 (120-204 VT), 120 min/ 214 -214 VT), 180 min 217 -217 VT) and 30 min 218 (30-218 VT). Mass loss (ML), colour change, density, tensile strength along the fibres, moisture exclusion efficiency and weight loss (WL) after brown rot fungus Coniophora puteana were determined and also light microscopy images were taken. Aspen veneers showed a ML of 5.3% between 120-214 VT (6.2%) and 30-2...

Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference

Wood is the most popular building material in the world due to its universal versatility, althoug... more Wood is the most popular building material in the world due to its universal versatility, although it has disadvantages - the difficulty to apply small diameter logs in construction, hygroscopicity and anisotropic swelling and shrinking. To solve these disadvantages, plywood from wood material is produced. Plywood is a material that can solve anisotropy, but it is still biodegradable by rot and stain fungi. Thermal treatment is a methodology that improves the durability of wood. In this paper aspen (Populus tremula L.), poplar (Populus x canadensis Moench) and birch (Betula pendula Roth) were treated by steam (WTT) and vacuum (TERMOVUOTO) devices under 160°C/50 min (birch and aspen), 204°C/2 h, 214°C/2 h, 217°C/3 h, 218°C/30 min (birch and poplar). Chemical changes in treated veneers were investigated by ATR-FTIR (Attenuated Total Reflection Fourier Transform Infrared Spectroscopy) in a range 2000 cm-1 – 800 cm-1. ATR-FTIR is a non-destructive methodology, which is important during ...

Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference

Wood is the most popular building material in the world due to its universal versatility, althoug... more Wood is the most popular building material in the world due to its universal versatility, although it has disadvantages - the difficulty to apply small diameter logs in construction, hygroscopicity and anisotropic swelling and shrinking. To solve these disadvantages, plywood from wood material is produced. Plywood is a material that can solve anisotropy, but it is still biodegradable by rot and stain fungi. Thermal treatment is a methodology that improves the durability of wood. In this paper aspen (Populus tremula L.), poplar (Populus x canadensis Moench) and birch (Betula pendula Roth) were treated by steam (WTT) and vacuum (TERMOVUOTO) devices under 160°C/50 min (birch and aspen), 204°C/2 h, 214°C/2 h, 217°C/3 h, 218°C/30 min (birch and poplar). Chemical changes in treated veneers were investigated by ATR-FTIR (Attenuated Total Reflection Fourier Transform Infrared Spectroscopy) in a range 2000 cm-1 – 800 cm-1. ATR-FTIR is a non-destructive methodology, which is important during ...