It is widely accepted that heat treatment of wood ameliorates its dimensional stability and color evolution. This study has analyzed the effects of heat treatment in color changes and hygroscopic properties of fir wood (Abies Borissi-regis Mattf.), exposed at 200º C for 2, 3 and 4h. Dimensional stability and absorption were measured after 1 day and 3 days immersion in water of 20 º C ± 3 temperature. Color evolution and color changes were analyzed in three different directions using the CIE L*a*b* color space. The results showed that heat treatment resulted in a darkened color and an improvement in the dimensional stability of wood. The visual changes in color were more distinct after 4h treatment. The total color differences (ΔΕ) of the surface of wood substrates appear to be directly correlated with the treatment time. Swelling percentage of the samples was found to be affected by the thermal treatment intensity. The higher percentage of swelling decrease was recorded at approximately 19.61% in 4h treatment duration in a tangential direction whereas, the lowest percentage of 0.54% was derived from 3h treatment duration in a radial direction.
Chemical Modification of Wood Using Vinegar and Benzoic Acid against Termites...Premier Publishers
Wood is a free gift of nature used for engineering, construction and in agricultural purposes. However, it has shortcomings when in contact with moisture, sunlight and organisms, which limits longevity in its applications. Chemical modification by acetylation and benzoylation of wood cellulose using vinegar and benzoic acid as modifying agents was carried out in heterogeneous phase. The extent of modification was calculated as weight percent gains. Burial in a termite hill for four months was done in order to investigate its biological resistance to termites as trial organisms. Acetylation or benzoylation of the wood cellulose carried out for 1 h yielded WPGs values in the range of 18-31 % (acetylation) and 11-25 % (benzoylation), while 3 h gave 15-25 % (acetylation) and 16-22 % (benzoylation). The following absorption peaks were indication of acetylation or benzoylation reactions: 3343-3375, 1715-1737, 1689-1658, 1621-1614, 1594-1593 and 1309-1377 cm-1 are due to –OH, C=O, C=C, and –CH3 as revealed by FT-IR results. The SEM images of the treated samples revealed a clear structural transformation of the native wood as a result of the chemical treatments. The modified wood cellulose was resistant to termite degradation, indicating that longevity can be achieved by the modifying agents.
The chemical (extractives and lignin) content and histological property (microscopic structure)
of tissues of Ricinodendron heudelotii (Baill, Pierre ex Pax), an angiosperm, were investigated for its potential
as a fibrous raw material for pulp and paper production. Bolts of about 70 cm were cut from the felled trees at
three different merchantable height levels of 10%, 50%, and 90% to obtain: corewood, middlewood and
outerwood samples. The fiber characteristics of the selected trees viz: the fiber length, fibre diameter and lumen
diameter were measured while the cell wall thickness was derived from the measured fibre dimensions. The
average fiber length, cell wall thickness, and lumen width, were 1.40 mm, 4.6 µm, and 32.3 µm, respectively.
The extractive and lignin contents were determined. Klason lignin content was about 30%. Extractive content of
R. heudelotii ranged from 0.41 to 0.5%. Based on these findings R. heudelotii is suitable for pulp and paper
production.
Development of Wood-Plastic Composite at Dedan Kimathi University of Technolo...IJERA Editor
Disposal of plastics and other solid wastes has been a major problem in Kenya. Most of these wastes can be
recycled through various ways and methods to produce new products. Plastics can be combined with sawdust to
develop composite materials for applications such as in building. In this project, a wood-plastic composite
(WPC) was developed from sawdust and plastic solid wastes.
The composite bore the advantages of both wood and plastics which can be applied in various sectors including
interior design work and in automotive among others, thereby curbing the problem of garbage accumulation in
the environment. The project provides eco-friendly solutions by making best use of the available resources
(wood and plastic resins) thus, finding sustainable solutions to the problem of limited waste dumping sites and
deforestation in the country. The composites were made from PP and HDPE thermoplastics and mahogany
sawdust obtained from our wood workshop in Dedan Kimathi University. From the tests carried out and results
obtained, it was found that, the composite has more advantages than the individual constituent materials.
Water absorption test revealed that all the samples took up water though not as much pronounced as for plain
sawdust. Additionally, the rate of water reduction was found to be excellent. They took less time to release the
absorbed water to the environment meaning that they can be applied in humid or wet environ. The composite
samples were easy to machine since they were easily shaped using a handsaw.
20 cm x 20 cm Flat boards of wood plastic composite (WPC) of thickness size of 0.5 cm was produced from three indigenous wood species (Funtumia elastica, Brachystegia kennedy and Milicia excelsa). WPCs were produced from each of selected wood species at two different wood/rHDPE mixing ratios of 1:1 and 1:1.5 at a constant nominal board density of 1g/m3. Effect of these production variables (wood species and mixing ratio) were investigated on physical and mechanical properties of WPC boards produced. Properties such as water absorption (WA), thickness swelling (TS), abrasion (AB), modulus of elasticity (MOE), modulus of rupture (MOR) and impact bending test (IB) were all carried out on the samples. Appropriate quantities of sawdust and pulverised nylon were sieved, weighed and mixed thoroughly to produce flat WPC boards from fabricated Hot-press plate machine at 1030 C with a constant pressure of 1.23N/mm2 for 20 minutes. Samples were cut into specific dimensions in accordance with British Standard (B.S D373 and D1181). Results shows that flat WPC boards produced from B. kennedy and M. excelsa were relatively low in moisture uptake but lower in wood /rHDPE mixing ratio of 1:1.5. However these wood species WPC boards were stiff and strong in strength properties but stiffer and stronger with wood /rHDPE mixing ratio of 1:1, additional abrasion values was lower in both B. kennedy and M. excelsa than F. elastica. Based on the findings that increased proportion of pulverised nylon to wood in WPC boards makes the boards to be plasticized with low strength properties, but highly dimensional stable, boards in these categories could be considered for low bearing load applications in both exterior and interior engineering materials.
Water Absorption, Thickness Swelling and Rheological Properties of Agro Fiber...iosrjce
IOSR Journal of Polymer and Textile Engineering (IOSR-JPTE) is ambitious to disseminate information and experience in education, practice and investigation between polimer, fibric and all the sciences involved in textile.
Chemical Modification of Wood Using Vinegar and Benzoic Acid against Termites...Premier Publishers
Wood is a free gift of nature used for engineering, construction and in agricultural purposes. However, it has shortcomings when in contact with moisture, sunlight and organisms, which limits longevity in its applications. Chemical modification by acetylation and benzoylation of wood cellulose using vinegar and benzoic acid as modifying agents was carried out in heterogeneous phase. The extent of modification was calculated as weight percent gains. Burial in a termite hill for four months was done in order to investigate its biological resistance to termites as trial organisms. Acetylation or benzoylation of the wood cellulose carried out for 1 h yielded WPGs values in the range of 18-31 % (acetylation) and 11-25 % (benzoylation), while 3 h gave 15-25 % (acetylation) and 16-22 % (benzoylation). The following absorption peaks were indication of acetylation or benzoylation reactions: 3343-3375, 1715-1737, 1689-1658, 1621-1614, 1594-1593 and 1309-1377 cm-1 are due to –OH, C=O, C=C, and –CH3 as revealed by FT-IR results. The SEM images of the treated samples revealed a clear structural transformation of the native wood as a result of the chemical treatments. The modified wood cellulose was resistant to termite degradation, indicating that longevity can be achieved by the modifying agents.
The chemical (extractives and lignin) content and histological property (microscopic structure)
of tissues of Ricinodendron heudelotii (Baill, Pierre ex Pax), an angiosperm, were investigated for its potential
as a fibrous raw material for pulp and paper production. Bolts of about 70 cm were cut from the felled trees at
three different merchantable height levels of 10%, 50%, and 90% to obtain: corewood, middlewood and
outerwood samples. The fiber characteristics of the selected trees viz: the fiber length, fibre diameter and lumen
diameter were measured while the cell wall thickness was derived from the measured fibre dimensions. The
average fiber length, cell wall thickness, and lumen width, were 1.40 mm, 4.6 µm, and 32.3 µm, respectively.
The extractive and lignin contents were determined. Klason lignin content was about 30%. Extractive content of
R. heudelotii ranged from 0.41 to 0.5%. Based on these findings R. heudelotii is suitable for pulp and paper
production.
Development of Wood-Plastic Composite at Dedan Kimathi University of Technolo...IJERA Editor
Disposal of plastics and other solid wastes has been a major problem in Kenya. Most of these wastes can be
recycled through various ways and methods to produce new products. Plastics can be combined with sawdust to
develop composite materials for applications such as in building. In this project, a wood-plastic composite
(WPC) was developed from sawdust and plastic solid wastes.
The composite bore the advantages of both wood and plastics which can be applied in various sectors including
interior design work and in automotive among others, thereby curbing the problem of garbage accumulation in
the environment. The project provides eco-friendly solutions by making best use of the available resources
(wood and plastic resins) thus, finding sustainable solutions to the problem of limited waste dumping sites and
deforestation in the country. The composites were made from PP and HDPE thermoplastics and mahogany
sawdust obtained from our wood workshop in Dedan Kimathi University. From the tests carried out and results
obtained, it was found that, the composite has more advantages than the individual constituent materials.
Water absorption test revealed that all the samples took up water though not as much pronounced as for plain
sawdust. Additionally, the rate of water reduction was found to be excellent. They took less time to release the
absorbed water to the environment meaning that they can be applied in humid or wet environ. The composite
samples were easy to machine since they were easily shaped using a handsaw.
20 cm x 20 cm Flat boards of wood plastic composite (WPC) of thickness size of 0.5 cm was produced from three indigenous wood species (Funtumia elastica, Brachystegia kennedy and Milicia excelsa). WPCs were produced from each of selected wood species at two different wood/rHDPE mixing ratios of 1:1 and 1:1.5 at a constant nominal board density of 1g/m3. Effect of these production variables (wood species and mixing ratio) were investigated on physical and mechanical properties of WPC boards produced. Properties such as water absorption (WA), thickness swelling (TS), abrasion (AB), modulus of elasticity (MOE), modulus of rupture (MOR) and impact bending test (IB) were all carried out on the samples. Appropriate quantities of sawdust and pulverised nylon were sieved, weighed and mixed thoroughly to produce flat WPC boards from fabricated Hot-press plate machine at 1030 C with a constant pressure of 1.23N/mm2 for 20 minutes. Samples were cut into specific dimensions in accordance with British Standard (B.S D373 and D1181). Results shows that flat WPC boards produced from B. kennedy and M. excelsa were relatively low in moisture uptake but lower in wood /rHDPE mixing ratio of 1:1.5. However these wood species WPC boards were stiff and strong in strength properties but stiffer and stronger with wood /rHDPE mixing ratio of 1:1, additional abrasion values was lower in both B. kennedy and M. excelsa than F. elastica. Based on the findings that increased proportion of pulverised nylon to wood in WPC boards makes the boards to be plasticized with low strength properties, but highly dimensional stable, boards in these categories could be considered for low bearing load applications in both exterior and interior engineering materials.
Water Absorption, Thickness Swelling and Rheological Properties of Agro Fiber...iosrjce
IOSR Journal of Polymer and Textile Engineering (IOSR-JPTE) is ambitious to disseminate information and experience in education, practice and investigation between polimer, fibric and all the sciences involved in textile.
A STUDY ON MECHANICAL PROPERTIES OF TREATED PALM SEED FIBER EPOXY COMPOSITEJournal For Research
Synthetic fibers composite fibers are more widely used because of its great property. Natural fiber epoxy composite is found to be an effective replacement of some kind of synthetic materials. Oil palm seed fiber is chosen as fiber because of its easy availability, less cost compared to other fibers, renewable, environment friendly, non-abrasive, biodegradable and enhanced properties. Palm seed fiber being available easily is also a disposal of fiber from its industries. Being a green composite 0il palm seed fiber epoxy composite was fabricated. In this paper chemical treatment with NaOH and H2O2 and mechanical properties of oil palm seed fiber epoxy composite was studied along with the morphological analysis of SEM images were conducted. Chemical treatments provided better adhesion between the fiber and matrix.
A Study on Mechanical Properties of Vinylester Based BioComposite Material wi...IJERA Editor
In composites a conglomeration produces material properties which are unavailable from individual constituent
materials. The use of petroleum based products as constituents in polymer matrix composite has raised concerns
regarding environmental issue and non-renewability of the resource. Therefore in this work an attempt has been
made to develop a biocomposite material using untreated dupion silk fiber as reinforcement material and vinyl
ester as matrix material with Potato Starch used as filler material by hand layup technique.
The biocomposites were prepared in varying percentage of filler addition (0%, 10%, 20%, and 30%) and
different mechanical tests (tensile, flexure and hardness) were conducted on the samples prepared to the ASTM
standards.
From the results of the experiments conducted on the specimen it can be concluded that the performance of 10%
Starch filler content Biocomposite is satisfactory in all aspects compared to 0%, 20%, and 30% Starch filler
content Biocomposites.
Development of a novel mycelium based bio-composite materialSiva Prasad
The presentation is of my final year project which deals with the development of a novel mycelium-based bio-composite material that has the potential to replace expanded polystyrene in packaging applications. All aspects of development and testing is discussed in detail.
Mechanical Characterization of Biodegradable Linen Fiber CompositesIJMER
Abstract: The conventional materials like iron, mild steel, cast iron etc are having good mechanical properties. Hence they are widely used in structural engineering applications. These conventional materials have some defects like formation of rust, low weight to strength ratio, high production cost. To overcome these defects, engineers started fabricating composite materials. Composites exhibit peculiar properties like different strengths in different directions, rust resistant, high strength to weight ratio, but they pollute the environment. Now the natural fibre composites are widely used in automobile industry. The natural fibres and resins are used to fabricate an eco friendly composite material. Lack of resources and increasing environmental pollution has evoked great interest in the research of materials that are
friendly to our health and environment. Bio polymer composites fabricated from natural fibres is currently
the most promising area in polymer sciences. This is designed to assess the possibility of fibre as reinforcing material in composites. Epoxy resin was made a stiffened panel to conduct tensile test. In this paper it is aimed to explain all possible ways to use natural composites in automobile components. The main advantages of using natural fibers are their degradability and light weight. They are environment friendly and also increase the fuel economy
Development of composite structure from recycled materialPradeepKumar3728
The circular economy is the need of an hour, keeping this in view I have developed a composite structure using the blend of used Polyethelene terephthalate bottles, Calcium Carbonate filler, and a natural resin called lac for commercial product and interior designing. This experiment was performed using two processes i.e casting and injection molding for the comparative analysis of the structure produced using the above-said process.
Jute, an eco-friendly and affordable fiber grown profusely in India, possess unique combination of properties suited for the manufacture of non-textile products. However, its contribution for technical applications is limited at present. In this research, an effort has been made to investigate the physical and morphological properties of jute fiber when incorporated in epoxy matrix with a view to widen the share of jute fibers for engineered applications. Composite specimens containing nonwoven jute mat and alkali treated short jute fibers with different weight percentages (1, 2 wt%) were made using epoxy resin. The water absorption, thickness swelling (TS) and morphology [scanning electron microscopy (SEM)] tests of the bio composites were performed. As the fiber fraction ratio was increased the values for water absorption (WA) and thickness swell (TS) were found to be increased. The samples reinforced with 2 wt. percent fiber fractions showed maximum WA and TS in both water environments.
Improvement of Tensile Properties of Recycled Low-Density Polyethylene by Inc...Dr. Amarjeet Singh
Plastics are used in versatile applications including
automobile, packaging, piping and house goods, these huge
uses attribute in the consumption of the oil reserves and the
emerged waste harm the environment when it disposed
irregularly. Recycling of plastics is one of the realistic
solutions to the aforementioned problems and to reduce
production cost. However, the reduction in mechanical
properties of recycled plastics limit their use and thus
reinforced plastics become popular because of their high
mechanical, physical and thermal properties. The effects of
calcium carbonate content from 0 to 15 wt.% on the tensile
properties of recycled low-density polyethylene (RLDPE)
were tested, the addition of calcium carbonate particles up to
15 wt.% was found to enhance the tensile strength and
modulus of elasticity of RLDPE samples. Three calcium
carbonate particle sizes (80, 200 and 500 µm) were mixed
with RLDPE to investigate the effect of particles size on the
tensile properties of RLDPE, it was found that the addition of
small filler particles resulted in a noticeable improvement of
tensile strength and modulus of elasticity of RLDPE
compared with large filler particles. It was also observed that
the addition of stearic acid slightly improves tensile
properties of RLDPE which may be related to improvement
of the interfacial adhesion between the filler and RLDPE. The
crystallization temperature and the degree of crystallinity of
RLDPE were increased by the addition of 7.5 wt.% calcium
carbonate particles because they act as nucleating agents.
Investigation of Energy Efficient Thermal Insulating Composites from Hemp Shi...IJERA Editor
This work presents the investigation results of physical-mechanical properties of fibrous hemp composite specimens produced from hemp shives and starch used as a binding material. For this purpose specimens with different amount of binding material, density and granulometric composition were used. Experimental results show that strength properties of composites linearly depend on the density of the material, as well as the density of hemp composites in all cases has the influence on change in thermal conductivity. During the research of mechanical properties it was determined that specimens with greater density and quantity of binding material had the greatest strength
Effect of bio-finishes on designer’s naturally coloured cotton khadi stripe f...IOSR Journals
Abstract: The present study involves the eco-friendly naturally coloured cotton DDCC-1 and white cotton
yarns which were used to produce pin and medium stripe khadi fabrics and given special bio-finishes viz.,
enzymatic de-sizing, bio-polishing and silicon softener finish and further tested to know their impact on different
structural, performance and durable properties. Multiple linear regressions were used to analyse their influence
on one another. It was found that on special finishing, both WC and DDCC-1 yarns became finer and slight
increase in cloth count; considerable reduction in bending length; improvement in crease recovery angle and
drapability of both the stripe fabrics was observed. Whereas, tensile strength and elongation were reduced; and
no considerable change was observed in abrasion and pilling. Keywords: DDCC-1, Designer’s fabrics, enzyme finish, medium stripe, naturally coloured cotton, physical
properties, pin stripe, softener wash, and special finish
A STUDY ON MECHANICAL PROPERTIES OF TREATED PALM SEED FIBER EPOXY COMPOSITEJournal For Research
Synthetic fibers composite fibers are more widely used because of its great property. Natural fiber epoxy composite is found to be an effective replacement of some kind of synthetic materials. Oil palm seed fiber is chosen as fiber because of its easy availability, less cost compared to other fibers, renewable, environment friendly, non-abrasive, biodegradable and enhanced properties. Palm seed fiber being available easily is also a disposal of fiber from its industries. Being a green composite 0il palm seed fiber epoxy composite was fabricated. In this paper chemical treatment with NaOH and H2O2 and mechanical properties of oil palm seed fiber epoxy composite was studied along with the morphological analysis of SEM images were conducted. Chemical treatments provided better adhesion between the fiber and matrix.
A Study on Mechanical Properties of Vinylester Based BioComposite Material wi...IJERA Editor
In composites a conglomeration produces material properties which are unavailable from individual constituent
materials. The use of petroleum based products as constituents in polymer matrix composite has raised concerns
regarding environmental issue and non-renewability of the resource. Therefore in this work an attempt has been
made to develop a biocomposite material using untreated dupion silk fiber as reinforcement material and vinyl
ester as matrix material with Potato Starch used as filler material by hand layup technique.
The biocomposites were prepared in varying percentage of filler addition (0%, 10%, 20%, and 30%) and
different mechanical tests (tensile, flexure and hardness) were conducted on the samples prepared to the ASTM
standards.
From the results of the experiments conducted on the specimen it can be concluded that the performance of 10%
Starch filler content Biocomposite is satisfactory in all aspects compared to 0%, 20%, and 30% Starch filler
content Biocomposites.
Development of a novel mycelium based bio-composite materialSiva Prasad
The presentation is of my final year project which deals with the development of a novel mycelium-based bio-composite material that has the potential to replace expanded polystyrene in packaging applications. All aspects of development and testing is discussed in detail.
Mechanical Characterization of Biodegradable Linen Fiber CompositesIJMER
Abstract: The conventional materials like iron, mild steel, cast iron etc are having good mechanical properties. Hence they are widely used in structural engineering applications. These conventional materials have some defects like formation of rust, low weight to strength ratio, high production cost. To overcome these defects, engineers started fabricating composite materials. Composites exhibit peculiar properties like different strengths in different directions, rust resistant, high strength to weight ratio, but they pollute the environment. Now the natural fibre composites are widely used in automobile industry. The natural fibres and resins are used to fabricate an eco friendly composite material. Lack of resources and increasing environmental pollution has evoked great interest in the research of materials that are
friendly to our health and environment. Bio polymer composites fabricated from natural fibres is currently
the most promising area in polymer sciences. This is designed to assess the possibility of fibre as reinforcing material in composites. Epoxy resin was made a stiffened panel to conduct tensile test. In this paper it is aimed to explain all possible ways to use natural composites in automobile components. The main advantages of using natural fibers are their degradability and light weight. They are environment friendly and also increase the fuel economy
Development of composite structure from recycled materialPradeepKumar3728
The circular economy is the need of an hour, keeping this in view I have developed a composite structure using the blend of used Polyethelene terephthalate bottles, Calcium Carbonate filler, and a natural resin called lac for commercial product and interior designing. This experiment was performed using two processes i.e casting and injection molding for the comparative analysis of the structure produced using the above-said process.
Jute, an eco-friendly and affordable fiber grown profusely in India, possess unique combination of properties suited for the manufacture of non-textile products. However, its contribution for technical applications is limited at present. In this research, an effort has been made to investigate the physical and morphological properties of jute fiber when incorporated in epoxy matrix with a view to widen the share of jute fibers for engineered applications. Composite specimens containing nonwoven jute mat and alkali treated short jute fibers with different weight percentages (1, 2 wt%) were made using epoxy resin. The water absorption, thickness swelling (TS) and morphology [scanning electron microscopy (SEM)] tests of the bio composites were performed. As the fiber fraction ratio was increased the values for water absorption (WA) and thickness swell (TS) were found to be increased. The samples reinforced with 2 wt. percent fiber fractions showed maximum WA and TS in both water environments.
Improvement of Tensile Properties of Recycled Low-Density Polyethylene by Inc...Dr. Amarjeet Singh
Plastics are used in versatile applications including
automobile, packaging, piping and house goods, these huge
uses attribute in the consumption of the oil reserves and the
emerged waste harm the environment when it disposed
irregularly. Recycling of plastics is one of the realistic
solutions to the aforementioned problems and to reduce
production cost. However, the reduction in mechanical
properties of recycled plastics limit their use and thus
reinforced plastics become popular because of their high
mechanical, physical and thermal properties. The effects of
calcium carbonate content from 0 to 15 wt.% on the tensile
properties of recycled low-density polyethylene (RLDPE)
were tested, the addition of calcium carbonate particles up to
15 wt.% was found to enhance the tensile strength and
modulus of elasticity of RLDPE samples. Three calcium
carbonate particle sizes (80, 200 and 500 µm) were mixed
with RLDPE to investigate the effect of particles size on the
tensile properties of RLDPE, it was found that the addition of
small filler particles resulted in a noticeable improvement of
tensile strength and modulus of elasticity of RLDPE
compared with large filler particles. It was also observed that
the addition of stearic acid slightly improves tensile
properties of RLDPE which may be related to improvement
of the interfacial adhesion between the filler and RLDPE. The
crystallization temperature and the degree of crystallinity of
RLDPE were increased by the addition of 7.5 wt.% calcium
carbonate particles because they act as nucleating agents.
Investigation of Energy Efficient Thermal Insulating Composites from Hemp Shi...IJERA Editor
This work presents the investigation results of physical-mechanical properties of fibrous hemp composite specimens produced from hemp shives and starch used as a binding material. For this purpose specimens with different amount of binding material, density and granulometric composition were used. Experimental results show that strength properties of composites linearly depend on the density of the material, as well as the density of hemp composites in all cases has the influence on change in thermal conductivity. During the research of mechanical properties it was determined that specimens with greater density and quantity of binding material had the greatest strength
Effect of bio-finishes on designer’s naturally coloured cotton khadi stripe f...IOSR Journals
Abstract: The present study involves the eco-friendly naturally coloured cotton DDCC-1 and white cotton
yarns which were used to produce pin and medium stripe khadi fabrics and given special bio-finishes viz.,
enzymatic de-sizing, bio-polishing and silicon softener finish and further tested to know their impact on different
structural, performance and durable properties. Multiple linear regressions were used to analyse their influence
on one another. It was found that on special finishing, both WC and DDCC-1 yarns became finer and slight
increase in cloth count; considerable reduction in bending length; improvement in crease recovery angle and
drapability of both the stripe fabrics was observed. Whereas, tensile strength and elongation were reduced; and
no considerable change was observed in abrasion and pilling. Keywords: DDCC-1, Designer’s fabrics, enzyme finish, medium stripe, naturally coloured cotton, physical
properties, pin stripe, softener wash, and special finish
Research of Physical Properties of Straw for Building Panelsinventionjournals
The development of new thermal insulation materials needs to evaluate properties and structure of raw materials, technological factors that make influence on the thermal conductivity of material. One of the most promising raw materials for production of insulation material is straw. The use of natural fibres as insulation is closely linked to the ecological building sector, where selection of materials is based on factors including recyclable, renewable raw materials and low resource production techniques. In current work results of research on structure, thermal conductivity, water vapour permeability and short term water immersion of triticale straw for production of thermal insulating straw panels are presented. Straw panels withdifferent densitywere prepared for thermal conductivity measurement. It was determined that lowest thermal conductivity of straw is reached when straw density ranges from 80kg/m3 to 120 kg/m3 . It was found that the macrostructure that changes with density increase has the great effect on thermal conductivity of materials. At the density range of 120-190 kg/m3 increase of thermal conductivity values are observed. Water vapour permeabilitywas analysed at the density ranges from 80 kg/m3 to 156 kg/m3 . Vapour permeability values grew with density increase from 2 to 2.5. Short term water absorption was evaluated by two parameters - as water absorption coefficient due to capillary action and short term water absorption by partial immersion. Water absorption coefficient shows sudden mass increase within the first 10 minutes and subsequent slow mass increase. Short term water absorption values show significant weight increase during 48 hours, which reaches 100 percent by mass
Role of primary forests for climate change mitigationCIFOR-ICRAF
Presented by Haruni Krisnawati of the Forest Research and Development Center Research Development and Innovation Agency, Ministry of Environment and at the 3rd Asia-Pacific Rainforest Summit, on 21-22 April 2018 in Yogyakarta, Indonesia
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
Cancer cell metabolism: special Reference to Lactate Pathway
Color changes and dimensional stability in fir wood (Abies Borissi-regis Mattf.) Modified by heat treatment
1. International Journal of Engineering Inventions
e-ISSN: 2278-7461, p-ISSN: 2319-6491
Volume 4, Issue 3 (August 2014) PP: 26-32
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Color changes and dimensional stability in fir wood (Abies Borissi-regis Mattf.) Modified by heat treatment Andromachi Mitani¹, Ioannis Barboutis² 1PhD Candidate, Aristotle University of Thessaloniki, Faculty of Forestry and Natural Environment, Laboratory of Wood products and Furniture Technology, 54124 Thessaloniki, tel.+30-2310-998898, fax.+30- 2310-998947 2Assosiate Professor, Aristotle University of Thessaloniki, Faculty of Forestry and Natural Environment, Laboratory of Wood products and Furniture Technology Abstract: It is widely accepted that heat treatment of wood ameliorates its dimensional stability and color evolution. This study has analyzed the effects of heat treatment in color changes and hygroscopic properties of fir wood (Abies Borissi-regis Mattf.), exposed at 200º C for 2, 3 and 4h. Dimensional stability and absorption were measured after 1 day and 3 days immersion in water of 20 º C ± 3 temperature. Color evolution and color changes were analyzed in three different directions using the CIE L*a*b* color space. The results showed that heat treatment resulted in a darkened color and an improvement in the dimensional stability of wood. The visual changes in color were more distinct after 4h treatment. The total color differences (ΔΕ) of the surface of wood substrates appear to be directly correlated with the treatment time. Swelling percentage of the samples was found to be affected by the thermal treatment intensity. The higher percentage of swelling decrease was recorded at approximately 19.61% in 4h treatment duration in a tangential direction whereas, the lowest percentage of 0.54% was derived from 3h treatment duration in a radial direction. Keywords: Abies Borissi-regis Mattf., Color, Dimensional stability, Heat treatment.
I. Introduction
Due to growing environmental concerns regarding the use of certain classes of preservatives, there has recently been a renewed interest in wood modification. Wood modification is a process of altering the material the aim being to overcome or ameliorate one or more of its drawbacks. Heat treatment of wood, an old and easy method of modification, has been commonly deployed since the middle of the last century and is nowadays produced industrially in several European countries. Heat treated wood is mainly used for garden furniture, windows, doors and wall or fence boarding, bathroom cabinets, floor material, musical instruments and kitchen furniture (Kartal et al 2008., Korkut and Hiziroglou., 2008). Wood modification has many capacities, it can bring about an enhancement in decay resistance or dimensional stability, reduce water sorption, improve weathering performance and a number of other things. The application of heat to wood produces degradation associated with chemicals changes in the material. Thermal modification is invariably performed between the temperature of 180º C and 260 º C. Thermal modification at temperatures lower than 140 º C results in only a slight change in material properties and higher temperatures cause unexpected degradation to the substrate. Wood darkening, and therefore color change, occurs due to both the temperature applied and time of the treatment. Treatment in produces greater color change compared to other treatments (Bekhta and Niemz., 2003). The changes in the physical properties of wood (color changes) with heat treatment is mainly the effect of a combination of the following factors: Heat degradation of the chemical constituents of wood and the removal or migration of extractives and other compounds (Korkut and Kocaefe., 2009). Li et al (2011) studied the effects of heat treatment on color change of Douglas fir and observed that the visual color changes arise drastically after heat treatment above 180 º C. Li et al also indicate that in species with pale colored wood, usually considered less appellative, the darkening would be an important advantage of the heat treatment giving the wood a “tropical flavor” highly valued in many countries. Guller (2012) when evaluating the color change of Pinus nigra wood, noticed that a longer duration of time and/or higher temperature gives a darker color to wood.
From earlier investigations, it is known that wood exposed to high temperatures becomes more dimensionally stable. Schultz et al (2008) stated that because of the chemical alteration of the wood cell wall structural polymers, the sorption behavior of the thermally treated wood is, therefore, altered. It was also highlighted that reduced hygroscopicity was most pronounced at higher relative humidity up to 70%. Significant part of literature is devoted to the idea that the hygroscopicity of heat treated wood can be considerably diverse with varying time and temperature. The decrease in the equilibrium moisture content of wood due to heat treatment leads to an improvement of wood dimensional stability. One of the studies reporting this, stated that it was possible to reduce the deformation caused by swelling by approximately 52% in spruce and 55% in pine
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just by adjusting the temperature. The increase in dimensional stability is also dependent on the wood direction and appears to be higher in tangential direction than in radial (Esteves and Pereira., 2009). Many researchers concluded that heat treatment of wood resulted in a large reduction in the hemicellulose content, and thus, improves the dimensional stability of the wood (Bekhta and Niemz., 2003). Esteves and Periera (2009) stated that in spruce, fir and poplar wood, the radial and tangential swelling has always been slighter in treated wood, and continued to decrease as the treatment become more severe. The improvement in dimensional stability depends on the wood species and the wood direction. The increase in dimensional stability for heat treated wood is mainly due to the decrease of wood hygroscopicity in view of the chemical changes at high temperatures. (this sentence does not make sense – the „in view of‟ needs to change) The decrease of swelling has already been examined by other researchers such as Sahin (2010), who noticed that fir and pine wood improved as concerns swelling in all directions after heat treatment at 190 o C and 212 o C for 2h. The results were statistically significant compared to the untreated specimens. As for heat treated fir wood, the reduction reached 40.6%. According to Sahin (2010) swelling is a phenomenon occuring under the fiber saturation point due to moisture absorption. Guller (2012) found out that pine soft wood resulted in a significant reduction in swelling percentage, especially in long durations under water (Metsa and Kortelainen., 2010, Tuong and Li., 2010). Gunduz et al (2008) also concluded that decreases in swelling to radial and tangential directions were found to be 34.46%, 51.73%, respectively. Cao et al (2011) investigated the dimensional stability of Chinese fir, finding that the heat treatment remarkably improved the dimensional stability and specifically increased as the treatment temperature and length of time increased too. Comparing the effect of the temperature and duration on dimensional stability, the temperature played a more determining role. Sahin (2010) studied the swelling and shrinkage of fir wood (Abies bornmulleriana Mattf.) and concluded that these physical properties improved in all directions indicating that the availability and accessibility of the free hydroxyl groups of the wood carbohydrates play an important role in the process of water absorption and desorption. The heat treatment altered the chemical structure of the wood, especially the hydroxyl groups. Tjeerdsma et al (1998) mentioned that one of the main reasons for the increase of the dimensional stability is the loss of the methyl radials of some guaiacylic and siringic units of lignin which lead to an increase of phenolic groups and an increase of the units proportion with free ortho positions. These chemical changes lead to higher lignin reactivity, with the formation of several crosslinks, responsible for the increase of dimensional stability. Through the increase of crosslinking, the molecule becomes less elastic and the cellulose microfibrils are less likely to expand and absorb water, explaining the decrease of the equilibrium moisture and the improvement on the dimensional stability. The present study was conducted to assess the effect of soft condition heat treatment on color change and dimensional stability of Abies Borissi-regis Mattf.fir wood, one of the most significant commercial wood produced in Greece.
II. Material And Methods
In this study, fir wood (Abies Borissi-regis Mattf.) was obtained from the Pertouli district of Trikala province in central Greece. Lumber from the logs was prepared in the wood products laboratory of the Forestry faculty, Aristotle university of Thessaloniki. Initially, lumber was cut in sawn samples of dimension 50 x 25 x 3 mm in axial section. These flitches were conditioned in the laboratory for about 1 year under 20 ± 2o C and 60 ± 5 % relative humidity. The wood samples were weighed and then dried in the oven at 103 o C±2 for 24h and reweighed, according to ISO 3130:1975, in order to estimate the mean moisture content of our material. The average moisture was 11.03% (SD 0.18) while the average density (oven dry weight/volume at 11.03% (SD: 0.18) moisture) of timber used were 0.391 g/cm3 (SD 0.037). The flitches were thermally treated in an oven at 200 o C in which the temperature could be controlled to ±3 o C and for three different periods of time (2, 3 and 4h) in the presence of air. The flitches were placed in the unit after the desired temperature had been reached and following thermal treatment the flitches were conditioned for 15 days. The final specimens for swelling and absorption were prepared according to ISO 4859:1982. The dimensions of the specimens were 20mm x 20mm x 30mm, with the length in axial direction. For each variable, 10 specimens were prepared. The swelling (in radial and tangential directions) and the absorption percentage was conducted after the immersion of the samples in the water of 20 ± 3o C for 1 and 3 days.
With the aim of determining the heat treatment effect on color change, a colorimeter Minolta Croma- Meter CR-400 was used and the test was carried out according to EN 7224-3:2003. The colour measurements of the specimens were recorded on the surface of the wood specimens before and after heat treatment in radial, tangential and longitudinal directions. For both treated and untreated samples, three sides (radial, tangential and longitudinal) of 17 specimens were measured, 66 in total. Colour changes were studied by the CIELAB system (Figure 1). This system is characterized by three parameters, Lightness (L*) from 0% (black) to 100% (white), a* from green (-a) to red (+a), and b* from blue (-b) to yellow (+b) which are used for colour opponent
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dimensions and C* for the chroma or saturation. The a* and b* chromaticity coordinates range from +128 (+a) for red to -127 for green and +128 (+b) for yellow to -127 (-b) for blue, respectively. The L*, a* and b* were determined for untreated and treated specimens and their variation with regard to the treatment (ΔL*, Δa*, Δb*) was also calculated. From the L*a*b* values, the difference in the lightness (ΔL*) and chroma coordinates (Δa* and Δb*), saturation (C*) (ΔC*) and total colour difference (ΔE) meaning the distance in L*, a*, b* colour space were calculated using the following equations. ΔL* = L*t – L*ut Equation (1) Δa* = a*t – a*ut Equation (2) Δb* = b*t – b*c Equation (3) C* = (a*2 + b*2)½ Equation (4) ΔE = (ΔL*2 + Δa *2 + Δb*2)½ Equation (5) ΔC*=C*t-Cut Equation (6) where, L*t, a*t, b*t are L*, a* and b* of the heated specimens L*ut, a*ut, b*ut are L*, a* and b* of the control specimens, respectively. One way analysis of variance (ANOVA), comparing the differences of values at 0.05 level was examined in order to determine the significant differences among various heat treatment combinations on color change and hygroscopic properties.
III. Results And Discussion
Mean values, standard deviation and coefficient of variation of the obtained color changes of treated wood for three different directions are presented in Table1. According to the results, the duration heat treatment has influenced color values. Fir wood showed a darker tone for all heat treatment conditions. The wood darkening was clearly visible and increased with treatment duration. As expected, the treatment decreased the Lightness (ΔL) and yellowness (Δb) of fir wood in contrast to redness (Δa) which increased, but the changes are not particularly important except for Lightness after 3h and 4h treatment. The highest Lightness reduction, was observed at 3 h treatment duration where it was noticed the values to be double compared to the untreated samples. Moreover, the coordinates a* and b* changed by the treatment conditions but not significantly. The most remarkable finding of these results is that the values of longitudinal direction are lower especially for a* coordinate meaning that longitudinal direction affected deeper than others direction due to parenchymal cells direction. Akgul and Korkut (2012) found out that the color coordinates of yellow (+b) and blue (-b) for Uludag fir wood treated for 120 o C, 150 o C and 180 o C for 6h and 10h presented a high variation in the heat treated samples, with increasing yellowness initially and decreasing yellowness later under more severe conditions. Regarding L* coordinate, as shown in figure 2, tends to decrease after heat treatment as the duration increases in a gradual and uniform way. Radial direction gave the highest values and longitudinal the lowest. More specifically, average lightness (L*) of the control specimens was about 76.96, 76.83 69.95 for radial, tangential and longitudinal direction, respectively, and decreased slightly in the first treatment to 69.39, 68.37 and 62.62, respectively (Fig 2). Between 3h and 4h treatment, there was a reduction of about 1.3%, not considered significant. As stated above, as much as L* coordinate approaches 0, this results in black becoming the colour which, in turn, darkens the wood. Chromaticity coordinates a* and b* did not follow the same trend as lightness. In the case of a* values (Fig.3) for the untreated samples, they appear to be 4.36, 4.38 and 4.82 for radial, tangential and longitudinal direction. Whereas for 2h, treated samples measurement they were found to be slightly increased without significant differences. The higher percentage of improvement was recorded between 2h and 3h treatment about 1.4%. The lower increase was observed in longitudinal direction. According to a* coordinate features, the fir wood after heat treatment tends to change to the colour red. A drift to the yellow colour (b*) was observed, according to the results and b* values (Fig. 4) which means that the appearance of the wooden surface approaches the yellow colour more than the blue one, as showed the corresponding axis showed (Fig 1). In particular, b* values referring untreated specimens reached 20.57, 20.1 and 19.5 for radial, tangential and longitudinal direction. After the first treatment for 2h, the values appeared to improve more than others about 24% abruptly. A gradual reduction of the values of b* coordinate was recorded after 3h and 4h treatment, not significantly important and naturally without approaching the untreated specimens values. The same progress with L* coordinate between the two last treatments was observed for a* and b* values meaning that between 3 and 4 hours of treatment the wood discoloration was not as intense as in the beginning.
These three chromaticity coordinates were used in order to compute the color difference (ΔΕ) and saturation index (ΔC) of total color change. The highest color deference (ΔΕ) values were 18.32 after heat treatment for 4h compared to untreated samples and they appeared to be correlated with treatment duration. The
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improvement appears to be particularly noticeable between the last two treatments in relation to the first one (2h). Observing the last two treatments, they seem to have no significant differences. Gonzales-Pena and Hale (2009) mentioned that ΔΕ could be a better predictor and a more reliable indicator than ΔL for most properties of wood. On the other hand, saturation index (ΔC) seems to decrease with the duration but the reduction is not considered significant. The results of this study is consistent with other findings in literature on different tree species. Gunduz et al (2011) mentioned according to their results in Uludag fir that the samples treated at 210 o C were found to be darker than the other ones treated at lower temperatures. In general, total color difference values seem to be higher at high temperatures due to total color change. L* values usually decreased after heat treatment, but a* and b* values generally increased. The data of this study agree with those of previous studies except for Δb which decreased but this is not significantly important. Li et al (2011) investigating the color change of Douglas fir, mentioned that the most interesting finding is that the darkening of the treated samples occurred evenly throughout the wood and not only on the surface when duration is over 1 hour. Guller (2012) studied the color change of softwood (Pinus nigra) at 200 o C for 1, 2 and 3h and found out that the color values decreased after treatments and the highest decreases in L* were recorded in severe and mild conditions, respectively. Guller also mentioned that the negative values of (ΔL), (Δb) and (Δa) indicated that the color became darker while increasing temperature and duration. Moreover Akgul and Korkut (2012) found out that Lightness of Uludag fir wood was significantly influenced and showed a darker tone under all treatment conditions but the maximum lightness reduction was obtained under the most intense treatment. Uludag fir wood presented the highest color difference (ΔΕ) value of about 12.81 after 10h treatment at 180 o C in comparison with Scots pine softwood which appeared similar values, about 12.02. Table 2 shows the average values of water absorption and swelling of the treated and untreated specimens after 1 and 3 days immersion in water. Swelling percentage of all thermal treatment was lower than this of the untreated specimens and the lowest percentage of about 2.58%, was recorded in 4h treated specimens, after 1 day immersion. Compared to three days immersion, the swelling rate for 1day was higher found to be affected by the thermal treatment intensity (Tab. 2). Additionally, the effects were found to be greater when the higher duration treatment was applied and higher the duration, the lower the swelling percentage was after the immersion of the samples in water. A marginally higher swelling percentage was recorded in tangential direction, as expected. The results depicted here indicate that lower water absorption (34.86%) was observed for 4h treated specimens after 1 day immersion in contrast to untreated specimens where the percentage of absorption was 44.11%. The differences among the control samples and those treated for 2 and 3h were relatively minor and the wood samples were not altered significantly. The reduction of absorption after 3 days immersion in water was not considerable although the specimens of every treatment conditions presented about 2% reduction as the duration of treatment was increasing. The effect of heat treatment on EMC and density of fir wood at 20ºC±2 and 60±5% conditions after four months is presented in table 3. Regarding moisture content, it was observed that the samples subjected to treatment conditions got lower moisture content in contrast to moisture of samples before treatment even though they were conditioned to get the EMC. The reduction in moisture content at treated samples compared with untreated was 48,86%, 51,19% and 53,49% after 2h, 3h and 4h respectively. The higher the treatment temperature is and the longer the treatment time, the lower the EMC. Previously published reports clearly indicate that heat treatment can significantly decrease moisture absorption in wood, higher temperature with longer duration cause the lowest hygroscopic property of wood. Based on the combined effect of the above factors, the OH groups available for moisture adsorption are significantly reduced by the heat treatment, which, in turn, decreases the hygroscopicity and EMC of wood (Li et al., 2001). As a result of this study, we determined that heat treatment causes mass losses in the wood, which has a negative effect on density. Thus, the greatest density loss occurred for treatment conditions of 200 ºC and 4h, estimated at about 2.78%, whereas the minimum density loss about 0.76%, occurred at treatment conditions of 200 ºC and 2h (Table 3). The result is similar to previously published reports for different species (Guller., 2012; Gunduz et al., 2009). Generally, the degradation of hemicelluloses into volatile products and the evaporation of water and extractives of wood were considered to be the main reason why density decreases.
IV. Conclusions
In conclusion, the results showed that heat treatment at 200 o C for three different durations (2h, 3h and 4h) resulted in a darkened color and decreased dimensional stability of fir wood. Specifically, longer treatment duration affected the discoloration but not significantly, due to big dimensions of treated flitches. The highest color deference (ΔΕ) values were recorded after heat treatment for 4h and appeared to be correlated with
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treatment duration. Saturation index (ΔC) seemed to decrease with the duration, but the reduction is not considered significant. The lowest percentage of swelling after 1day immersion was recorded in 4h treated specimens whereas the highest swelling rate was measured after 1day immersion without being significantly important. Furthermore, larger decreases were found to occur in the tangential direction rather than in the radial. Heat treatment also reduced wood density and EMC depending on time and temperature of treatment conditions Heat treatment is considered an environmentally friendly process producing more stable products with alluring appearance because of the color. Due to its “new” appearance in color and stability, heat treatment is a viable method and the resulting products can be applied outdoors such as garden furniture, window frames e.t.c. From this research, it can be ascertained that under relatively soft conditions of heat treatment, we can be led to improved color and hygroscopic properties of this important commercial wood that is produced in Greece. Further studies are in progress to determine the influence of heat treatment in more intense conditions (Temperature-time) and its effectiveness in other properties of fir wood. REFERENCES
[1]. Akgul, M., Korkut S., 2012: The effect of heat treatment on some chemical properties and color in Scots pine and Uludag fir wood. International journal of physical sciences. 7(21), 2854-2859.
[2]. Bazyar, B., 2012: Decay resistant and physical properties of oil heat treated aspen wood. Bi resources. 7(1), 696-705.
[3]. Cao, Y., Lu J., Huang, R., Jiali J., 2012: Increased dimensional stability of chinese fir through steam-heat treatment. European Journal Wood Poducts. 70, 441-444.
[4]. Esteves, M.B., Pereira, H.M., 2009: Wood Modification by heat treatment: A Review. Bioresources. 4(1), 370-404.
[5]. Gündüz, G., S. Korkut and D.S. Korkut., 2007: The Effects of Heat Treatment on Physical and Technological Properties and Surface Roughness of Camiyanı Black Pine (Pinus nigra Arn. subsp. pallasiana var. pallasiana) Wood. Bioresource Technology, Vol: 10.1016/j. biortech. 2007.05.015.
[6]. Gunduz, G., Aydemir, D., Korkut S., 2010: The effects of Heat Treatment on some Mechanical Properties and Color Changes of Uludag Fir Wood. Drying Technology, 28:249-255.
[7]. Guller, B., 2012: Effects of heat treatment on density, dimensional stability and color of Pinus nigra. African journal of biotechnology. 11(9). 2204-2209.
[8]. Hill Callum, A. S., 2006: Wood modification, Chemical, Thermal and other Processes. Wiley series renewable resources. Edition January 2006. 260 pages, Hardcover. pp. 99-114
[9]. Li X., Cai Z., Mou Q., Wu Y. , Lia Y., 2011: Effects of Heat Treatment on Some Physical Properties of Douglas Fir (Pseudotsuga Menziesii) Wood. Advanced Materials Research. 197-198, 90-95. [10]. Ozguven, A., Ozcelik, Y., 2013: Investigation of some property changes of natural building stones exposed to fire and high heat. Constructions and Building Materials. 38, 813-821.
[11]. Sahin, H., 2010: Characteristics of heat treated Turkish pine and fir wood after Thermowood Processing. Journal of Environmental biology. 31(6), 1007-1011.
[12]. Sahin, H., Arslan, B., Korkut, S., Sahin C., 2010: Colour Changes of Heat Treated Woods of Red-Bub Maple, European Hophornobeam and Oak. Colour research and application. 36(6), 462-466.
[13]. Schultz, P., Militz H., Freeman, M.H., Goodell, B., Darrel H., 2008: Development of Commercial Wood Preservatives. Efficacy, Enviromental, and Health Issues. 1953-II. American Chemical Society. Division of Cellulose and Renewable Materials. pp. 373- 377, 381-382.
[14]. Todorovic, N., Popovic, Z., Milic, G., Popadic, R., 2012: “Estimation of heat treated beechwood properties by color change”. BioResources 7(1), 798-815.
[15]. Tuong, V. M., Li, J., 2010: Effects of heat treatment on change in color and dimensional stability of Acacia hybrid wood. Bioresources 5(2), 1257-1267, 1257.
Figure 1. CIELAB coordination system pictured the color changes in L*, a* and b* coordinates (Ozguven and Ozcelik, 2013).
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Lightness of color
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Figure 2. Effect of heat treatment duration in three different directions on L*
a* Coordinate
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Figure 3. Effect of heat treatment duration in three different directions on a*
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Figure 4. Effect of heat treatment duration in three different directions on b*