Influence of ANO3 and ANO3·nH2O Nitrates on the Deformation Properties of Aluminosilicate Adhesives for Wood Products and Structures

2021 ◽  
Vol 1038 ◽  
pp. 210-220
Author(s):  
Sergii G. Guzii ◽  
Volodymyr Romaniuk ◽  
Svitlana Davydivna Lapovska ◽  
Oleg Semkiv ◽  
Ihar Bazhelka

As a result of the research, the deformation properties of aluminosilicate adhesives modified with nitrate salts and intended for gluing wooden products and structures made of pine, beech and oak wood at different stages of their hardening were determined. Considering that pine is the most common wood in the manufacture of products and structures, then in order to reduce the numerical values of the elastic modulus in glued materials, it is advisable to add ammonium, lithium and sodium nitrates in an amount of 0.5%, potassium nitrate in an amount of 1% into the composition of an aluminosilicate adhesive. which will ensure the approximation of the elastic modulus values to the values of the unmodified aluminosilicate adhesive and will significantly affect the water resistance of the glue joint and the depth of penetration of the adhesive into the wood structure. For gluing beech wood products to reduce the elasticity modulus, it is advisable to introduce 0.5% ammonium and potassium nitrates and 1% lithium and sodium nitrates, which will reduce the numerical values of the elastic modulus in glued materials by 1.18 and 1.53 times compared with the values of the elastic modulus of the unmodified aluminosilicate adhesive. For gluing oak wood products to reduce the elasticity modulus, it is advisable to introduce 0.5% potassium nitrate and 1.5% sodium nitrate, which will reduce the numerical values of the elastic modulus in glued materials by 1.4 and 2.83 times compared to the values modulus of elasticity of unmodified aluminosilicate adhesive.

2021 ◽  
Vol 325 ◽  
pp. 143-149
Author(s):  
Sergii G. Guzii ◽  
Ihar Bazhelka ◽  
Volodymyr Romaniuk ◽  
Svitlana Davydivna Lapovska

The article presents the results of studies of the effect of lithium, sodium, potassium and ammonium nitrates on the physical and mechanical properties of aluminosilicate adhesives intended for gluing wood and structures based on them. Nitrates were introduced into the aluminosilicate adhesive of composition Na2O·Al2O3·6SiO2·20H2O in amounts of 0.5, 1 and 1.5 wt. %. Changes in the shear strength along the fibers of substrates made of pine, beech, and oak wood were studied after 7 and 28 days of hardening of aluminosilicate adhesives in vivo. It is shown that for gluing pine wood it is most expedient to use adhesives containing lithium nitrate, potassium nitrate and ammonium nitrate is within 1.5 wt. %, the shearing strength along the fibers after 28 days of hardening is 1.7-1.8 times higher than the strength of the adhesive without additives. For gluing beech wood, it is most advisable to use adhesives containing potassium and ammonium nitrate in an amount of 1.5 wt. %, the shearing strength along the fibers after 28 days of hardening is 1.5 times lower than the strength of the adhesive without additives. For gluing oak wood, it is most advisable to use adhesives containing lithium nitrate, potassium nitrate and ammonium nitrate in amounts of 0.5 and 1.5 wt. %, the shear strength along the fibers increases by 1.3-1.5 times for 7 and 28 days of hardening compared to the strength of the adhesive without additives. According to the degree of influence on strength, modifying additives can be ranked in the series LiNO3×3H2O>KNO3>NH4NO3>NaNO3.


BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 8965-8980
Author(s):  
Jacek Barański ◽  
Aleksandra Konopka ◽  
Tatiana Vilkovská ◽  
Ivan Klement ◽  
Peter Vilkovský

The drying process was examined relative to parameters’ influence on the deformation and surface layer color changes of beech wood (Fagus sylvatica L.) and oak wood (Quercus robur L.). The goal was to analyze the impact of drying process conditions, wood and growth rings types, and load on the deformation and surface color changes of drying thin wooden elements. A further aim was to reduce the time of the lamella drying and minimize wood products defects. During each drying, 40 pieces of wood were dried, divided into two groups. For the first group, 30 pieces were dried under a uniformly distributed load of approximately 50 kg, while for the second group, 10 samples were dried without weight. The lamellas dried under load exhibited fewer cup, bow, and twist deformations than the lamellas dried without load. Cracks in the dried lamellas occurred comparably in those dried under and without load. Color changes in the specimens before and after drying were observed and measured. The differences in colorimetric parameters (a, b, and L) between wood without defects and with defects were less marked after drying than before drying. The color changes were only noticed in the surface layers of the specimens.


2019 ◽  
Vol 292 ◽  
pp. 108-113 ◽  
Author(s):  
Josef Fládr ◽  
Petr Bílý ◽  
Roman Chylík ◽  
Zdeněk Prošek

The paper describes an experimental program focused on the research of high performance concrete with partial replacement of cement by fly ash. Four mixtures were investigated: reference mixture and mixtures with 10 %, 20 % and 30 % cement weight replaced by fly ash. In the first stage, the effect of cement replacement was observed. The second phase aimed at the influence of homogenization process for the selected 30% replacement on concrete properties. The analysis of macroscopic properties followed compressive strength, elastic modulus and depth of penetration of water under pressure. Microscopic analysis concentrated on the study of elastic modulus, porosity and mineralogical composition of cement matrix using scanning electron microscopy, spectral analysis and nanoindentation. The macroscopic results showed that the replacement of cement by fly ash notably improved compressive strength of concrete and significantly decreased the depth of penetration of water under pressure, while the improvement rate increased with increasing cement replacement (strength improved by 18 %, depth of penetration by 95 % at 30% replacement). Static elastic modulus was practically unaffected. Microscopic investigation showed impact of fly ash on both structure and phase mechanical performance of the material.


Author(s):  
Dilpreet Singh ◽  
Pulak Mohan Pandey ◽  
Dinesh Kalyanasundaram

In this article, the nano and microhardness and the elastic modulus of the human elbow bones (humerus, ulna and radius) were studied. The nano properties were studied using load controlled technique with a load of 20 mN, while the micro properties were studied under 1 N load. A total of nine bone samples from three cadavers of ages between 45 and 55 years were tested. The measurements were carried out on both osteonal and interstitial bone in the longitudinal direction. The nanoindentation results indicated higher values for interstitial bone (hardness: 0.74 ± 0.09 GPa, elastic modulus: 19.05 ± 1.92 GPa) than for osteonal bone (hardness: 0.53 ± 0.05 GPa, elastic modulus: 16.66 ± 1.55 GPa). Consistent results were obtained at a depth of penetration between 1.1 μm to 1.5 μm in nanoindentation. In the case of microindentation, the microhardness and elastic modulus of interstitial bone was found to be 0.65 ± 0.07 GPa and 20.60 ± 2.27 GPa. Whereas for osteonal bone it was observed to be 0.60 ± 0.08 GPa and 14.56 ± 1.42 GPa respectively. The depth of penetration varies between the 8 μm to 11 μm for microindentation studies. In both measurement scales, a noticeable difference was observed between the osteonal and interstitial bone properties. As bone is a hierarchical structure, identifying the mechanical properties at the lamellar level helps in understanding the local mechanical environment of basic elements of the bones and predicting the behavior of the bone due to physiological loading.


2015 ◽  
Vol 820 ◽  
pp. 320-324
Author(s):  
T.C.F. Melo-Silva ◽  
C.L. Melo-Silva ◽  
C.F. Carvalho ◽  
A.B. Teixeira ◽  
J.F.C. Lins ◽  
...  

The aim of this study was to determine the hardness and the elasticity modulus of the two composite resins base of BISGMA with different inorganic particles: a nanoparticulated with a ceramic withload, (Filtek Z350XT-3M) with and without thermal activation and a microhybrid with no ceramic load (Opallis-FGM). The samples were prepared and subjected to the tests of Vickers hardness (Shimadzu HMV) and acoustic excitation pulse (Sonelastic ®). The samples were divided into three groups: G1-Filtek Z350 XT; G2-Filtek Z350XT MO (subject to further polymerization microwave) and G3-Opallis. The results showed that the hardness of G2 was significantly higher than the groups G1 and G3. The elastic modulus was higher than the G2 to G1 and G3. One can conclude that the resins filled with inorganic ceramic filler showed higher hardness and elastic modulus. The thermal activation increased the hardness and the elasticity modulus of the resin with ceramic load.


2021 ◽  
Author(s):  
◽  
Pamela I Chester

<p>Palynological investigations aimed at reconstructing the vegetation history of the Grevena Province, northwestern Greece were conducted in association with an archaeological research project. Fossil pollen, spores, microscopic charcoal particles, and sediment stratigraphies of radiocarbon-dated sediment cores from three sites in pine, beech, and oak woodland zones provide evidence of climatic changes, land use, and erosion during the last 3500 years. Identification of pollen and spores was aided by an extensive reference collection of local species and construction of a pollen key modelled on that of Faegri & Iversen (1989). Extant vegetation units are characterized by their contemporary pollen assemblages. Surface samples collected along an elevational transect show that a fairly direct relationship exists between the major vegetation zones and pollen deposition: pine, beech, and oak pollen predominate in their respective zones. Over-representation of pine pollen is notable. The sequence from Gomara site in the pine wood-pasture zone at 1750 m asl covers the time span c. 1340 BC to 700 AD. A local open pine wood was gradually replaced by beech after c. 890 BC, perhaps through reduced disturbance and/or increased precipitation. A herbaceous pollen spike at c. 80 BC resulted from deposition of volcanic ash. Pine wood replaced beech at c. 330 AD. Two periods of accelerated erosion coincide with the pine wood phases and with anthropogenic burning and grazing. These periods are separated by a period of abandonment when the climate was probably wetter. The sequence from Anelia site in the beech wood zone at 1440 m asl spans c. 1560-1989 AD. The site was surrounded by beech wood for the duration of the sequence. Regional and local burning of vegetation is indicated by an abundance of microscopic charcoal particles from c. 1560 until c. 1730 AD, when it ceased. Periods of erosion occurred during this period. After c. 1730 AD a homogeneous peat formed on the wetland, suggesting a period of greater landscape stability. From pollen evidence, a variety of land-use practices such as cereal cultivation, grazing, coppicing, and lumbering were carried out in the vicinity of the site especially before c. 1730 AD, but these diminished after 1920 AD. The lower part of the sequence from Kellia site in the oak wood-steppe zone at 580 m asl is insecurely dated, but the upper part spans c. 1230-1989 AD. The lowlands were covered with deciduous/semi-evergreen oak woods for the duration of the sequence. Since c. 1230 AD land close to the site was intensively cultivated with a variety of cereals. Burning occurred frequently throughout the period. The ratio of deciduous to semi-evergreen oak pollen is correlated with temperature and indicates a decline from c. 1230-1680 AD, after which temperature increased, a pattern similar to that of the Little Ice Age. Frontispiece The cultural landscape of Grevena Province looking NE towards the Vourinos Mountains on the eastern border of Grevena, from a prominent hill about 1 1/4 km NW of the modern village of Itea. In the foreground is the stubble of a wheat field. Beyond is an 18th century church dedicated to Aghia Panaghia. The middle ground is the steppe oak wood pasture of Grevena plains. Recent erosion on the sides of gullies can be seen here, even though they appear to be well vegetated. Frescoes in the church are shown in the enlargement. It stands on a registered archaeological site, Grevena Project 108 (21 degrees 36.18' E, 40 degrees 04.29' N, 640 m asl) that covers more than 10,000 m2. Archaeological evidence dating to Early Iron Age, Archaic, Classical, Hellenistic, Roman, Early Medieval and Ottoman periods has been recorded.</p>


2021 ◽  
Author(s):  
◽  
Pamela I Chester

<p>Palynological investigations aimed at reconstructing the vegetation history of the Grevena Province, northwestern Greece were conducted in association with an archaeological research project. Fossil pollen, spores, microscopic charcoal particles, and sediment stratigraphies of radiocarbon-dated sediment cores from three sites in pine, beech, and oak woodland zones provide evidence of climatic changes, land use, and erosion during the last 3500 years. Identification of pollen and spores was aided by an extensive reference collection of local species and construction of a pollen key modelled on that of Faegri & Iversen (1989). Extant vegetation units are characterized by their contemporary pollen assemblages. Surface samples collected along an elevational transect show that a fairly direct relationship exists between the major vegetation zones and pollen deposition: pine, beech, and oak pollen predominate in their respective zones. Over-representation of pine pollen is notable. The sequence from Gomara site in the pine wood-pasture zone at 1750 m asl covers the time span c. 1340 BC to 700 AD. A local open pine wood was gradually replaced by beech after c. 890 BC, perhaps through reduced disturbance and/or increased precipitation. A herbaceous pollen spike at c. 80 BC resulted from deposition of volcanic ash. Pine wood replaced beech at c. 330 AD. Two periods of accelerated erosion coincide with the pine wood phases and with anthropogenic burning and grazing. These periods are separated by a period of abandonment when the climate was probably wetter. The sequence from Anelia site in the beech wood zone at 1440 m asl spans c. 1560-1989 AD. The site was surrounded by beech wood for the duration of the sequence. Regional and local burning of vegetation is indicated by an abundance of microscopic charcoal particles from c. 1560 until c. 1730 AD, when it ceased. Periods of erosion occurred during this period. After c. 1730 AD a homogeneous peat formed on the wetland, suggesting a period of greater landscape stability. From pollen evidence, a variety of land-use practices such as cereal cultivation, grazing, coppicing, and lumbering were carried out in the vicinity of the site especially before c. 1730 AD, but these diminished after 1920 AD. The lower part of the sequence from Kellia site in the oak wood-steppe zone at 580 m asl is insecurely dated, but the upper part spans c. 1230-1989 AD. The lowlands were covered with deciduous/semi-evergreen oak woods for the duration of the sequence. Since c. 1230 AD land close to the site was intensively cultivated with a variety of cereals. Burning occurred frequently throughout the period. The ratio of deciduous to semi-evergreen oak pollen is correlated with temperature and indicates a decline from c. 1230-1680 AD, after which temperature increased, a pattern similar to that of the Little Ice Age. Frontispiece The cultural landscape of Grevena Province looking NE towards the Vourinos Mountains on the eastern border of Grevena, from a prominent hill about 1 1/4 km NW of the modern village of Itea. In the foreground is the stubble of a wheat field. Beyond is an 18th century church dedicated to Aghia Panaghia. The middle ground is the steppe oak wood pasture of Grevena plains. Recent erosion on the sides of gullies can be seen here, even though they appear to be well vegetated. Frescoes in the church are shown in the enlargement. It stands on a registered archaeological site, Grevena Project 108 (21 degrees 36.18' E, 40 degrees 04.29' N, 640 m asl) that covers more than 10,000 m2. Archaeological evidence dating to Early Iron Age, Archaic, Classical, Hellenistic, Roman, Early Medieval and Ottoman periods has been recorded.</p>


Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7616
Author(s):  
Georg Baumann ◽  
Reinhard Brandner ◽  
Ulrich Müller ◽  
Alexander Stadlmann ◽  
Florian Feist

In order to use wood for structural and load-bearing purposes in mechanical engineering, basic information on the impact behaviour of the material over a wide temperature range is needed. Diffuse porous hardwoods such as solid birch wood (Betula pendula) and solid beech wood (Fagus sylvatica) are particularly suited for the production of engineered wood products (EWPs) such as laminated veneer lumber (LVL) or plywood due to their processability in a veneer peeling process. In the frame of this study, solid birch wood and solid beech wood samples (300 × 20 × 20 mm3) were characterised by means of an impact pendulum test setup (working capacity of 150 J) at five temperature levels, ranging from −30 °C to +90 °C. The pendulum hammer (mass = 15 kg) was equipped with an acceleration sensor in order to obtain the acceleration pulse and deceleration force besides the impact bending energy. In both solid birch wood and solid beech wood, the deceleration forces were highest at temperatures at and below zero. While the average impact bending energy for solid birch wood remained almost constant over the whole considered temperature range, it was far less stable and prone to higher scattering for solid beech wood.


The longer term prospects for the use of wood depend upon the continued availability of suitable material and the ability of wood products to compete in cost and performance with comparable products made from other materials. The availability of both hardwoods and softwoods is considered against a background of a world usage which is rising at just under 2 % per annum and the conclusion is reached that sufficient wood will be available to meet the growing demands for the next hundred years or so although the nature and quality of the material available will not be the same as at present. The importance of successful regeneration and renewal of forests, particularly in tropical areas, is emphasized in affecting the future for wood beyond that term. The competition from other materials has been considered for various usage categories. For structural uses the prospect is good; a number of factors indicate a growth in structural usage, and competition from other structural materials is not likely to be severe while supplies of adequate material are available. The use of timber for joinery, furniture, cladding and utility markets has been reduced in recent years, particularly as a result of developments in plastics technology. There is a need to develop products in which wood is combined with other materials to give the required properties. It is expected that the use of wood for decorative purposes will continue in high demand. The importance of developing new products, particularly utilizing the substantial amount of waste available, and of marketing wooden products which are more closely designed to meet consumer needs, is emphasized.


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