scholarly journals Properties of Hungarian oak(quercus conferta Kit.) wood from the Hilandar Monastery forest

2007 ◽  
pp. 145-154
Author(s):  
Zdravko Popovic ◽  
Nebojsa Todorovic
Keyword(s):  
Compressive Strength ◽  
Bending Strength ◽  
Wood Quality ◽  
Wood Properties ◽  
Strength Properties ◽  
Statistical Parameters ◽  
Wood Moisture ◽  
Volume Porosity ◽  
Study Results ◽  
Basic Strength

This paper presents the study results of the basic physical and strength properties of Hungarian oak (Quercus conferta Kit.) wood from the Kakovo Monastery forests of Hilandar Monastery in Greece. Wood properties were analyzed in detail, as an indispensable proof of wood quality and its use for joinery, interiors and wooden floors. The basic physical properties of wood (moisture content at the time of tree felling, density and volume porosity) and the basic strength properties (compressive strength, bending strength and module of elasticity) were researched. The results are presented in Tables and in Diagrams with statistical parameters and compared to the literature data. The correlation of the study properties of wood was also analyzed.

Technological Properties of Wood from Trees in Polluted Regions

IAWA Journal ◽  
1986 ◽  
Vol 7 (4) ◽  
pp. 389-397 ◽  
Author(s):  
A. Frühwald
Keyword(s):  
Moisture Content ◽  
Wood Quality ◽  
Wood Properties ◽  
Biological Indicators ◽  
Strength Properties ◽  
West Germany ◽  
Technological Properties ◽  
Growth Rings ◽  
Physical Chemical ◽  
Faster Development

Wood quality from about 230 healthy and diseased fir, spruce, pine and beech trees from various locations in West Germany was tested. In general results are satisfactory for mechanical wood properties, but some physical, chemical and biological indicators lead to the conclusion that logs from heavily diseased trees may be attacked a !ittle earlier and faster by microorganisms during storage. Width of growth rings is reduced in severely damaged softwood trees on most locations whereas beech shows no significant reduction. Declining health of the trees had no or little influence on wood density; the modulus of elasticity and strength were at normal levels and independent of tree damage. Width and moisture content of sapwood were reduced little in pines but more in spruce and fir. A tendency to a more intensely developed irregular brown heartwood in severeIy damaged beech trees could not be proved until now. Storage of spruce in a log yard for four months has shown a slightly faster development of discoloration caused by fungi in diseased trees whereas after seven months wood from healthy trees was more discoloured. After storage strength properties are not or only slightly reduced, but no difference was found between trees assigned to the various health classes. After two years of storage under sprinkling water, pine logs from healthy and diseased trees show no difference in discoloration.

scholarly journals Effect of Fiber Reinforcement on the Compression and Flexural Strength of Fiber-Reinforced Geopolymers

2021 ◽  
Vol 11 (21) ◽  
pp. 10443
Author(s):  
Michał Łach ◽  
Bartłomiej Kluska ◽  
Damian Janus ◽  
Dawid Kabat ◽  
Kinga Pławecka ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Building Materials ◽  
Bending Strength ◽  
Strength Properties ◽  
Attractive Alternative ◽  
Reinforcing Fibers ◽  
Different Types ◽  
The Matrix ◽  
Glass Carbon

This work aimed to determine the effect of the addition of different types of reinforcing fibers on the strength properties of geopolymers such as flexural and compressive strength. Geopolymers are an attractive alternative to conventional binders and building materials; however, one of the main problems of their widespread use is their low resistance to brittle fracture. To improve the mechanical properties, reinforcement in the form of glass, carbon, and basalt fibers (as grids) was applied to geopolymers in the following work. Additionally, composites with these fibers were produced not only in the matrix of pure geopolymer but also as a hybrid variant with the addition of cement. Furthermore, basalt grids were used as reinforcement for geopolymers not only based on ash but also metakaolin. An additional variable used in the study was the molar concentration of the alkali solution (5 M and 10 M) for the different types of geopolymer samples. The mechanical properties of geopolymer materials and geopolymer–cement hybrids are the highest when reinforcement in the form of carbon fiber is used. Strength values for geopolymers reinforced with basalt mats depend on the number of reinforcement layers and the concentration of the alkaline solution used. All produced composites were tested for compressive strength and bending strength. When using basalt mesh, it was possible to achieve a bending strength of 12 MPa. The highest compressive strength that was achieved was the value of 66 MPa, while for samples not reinforced with fibers, only about 40 MPa was achieved.

scholarly journals Basic strength properties of beech wood in coppice forests G.J. "Crni Vrh - Kupinovo",

2004 ◽  
pp. 141-153
Author(s):  
Zdravko Popovic ◽  
Nebojsa Todorovic
Keyword(s):  
Bending Strength ◽  
Beech Wood ◽  
Tree Height ◽  
Strength Properties ◽  
Scientific Production ◽  
Management Unit ◽  
Production Experiment ◽  
Shock Resistance ◽  
Coppice Forest ◽  
Basic Strength

The basic mechanical properties of beech wood in coppice forest, locality Bor-Boljevac, Management unit "Crni Vrh-Kupinovo" were studied: Bending strength, modulus of elasticity in bending and shock resistance. Eight trees were taken from two series covered by the scientific-production experiment in this management unit. The statistically processed results were presented for each tree. There is a very strong correlation of the general linear form y=ax+b between the study properties, except between density and shock resistance. Static bending strength decreases mildly with tree height. The analysis shows that the average values of the study properties of beech wood at this locality are approximately the same as the values at other localities in the former SFRY. The only deviation is shock resistance.

scholarly journals Changes in the Strength Properties and Phase Transition of Gypsum Modified with Microspheres, Aerogel and HEMC Polymer

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3486
Author(s):  
Justyna Ciemnicka ◽  
Karol Prałat ◽  
Artur Koper ◽  
Grzegorz Makomaski ◽  
Łukasz Majewski ◽  
...  
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Compressive Strength ◽  
Bending Strength ◽  
Strength Properties ◽  
Test Results ◽  
Strength Parameters ◽  
Scanning Calorimetry ◽  
Binding Material ◽  
The Impact

The paper presents an assessment of the impact of using additives on the strength of a binding material, i.e., building gypsum, and also the phase transformation that takes place in it. Microspheres, aerogel and polymer (HEMC) additives were added to a building gypsum slurry with a water to gypsum ratio of 0.75. In order to investigate their influence on bending strength, compressive strength, and the effect of high temperatures, differential scanning calorimetry (DSC), as well as tests of the multicomponent binder, were carried out in accordance with the applicable PN-EN 13279-2:2005 standard. The obtained test results allowed to determine that the used additives influenced the strength parameters of the obtained composites. It was shown that the applied additives decreased the compressive and bending strength of the modified gypsum. Despite these properties, the obtained gypsum materials are environmentally friendly because they reuse wastes, such as microspheres. Out of all the applied additives, the use of microspheres in an amount of 10% caused a decrease in the bending strength by only 10%, and an increase in the compressive strength by 4%.

Graphene Additives Effect on Mechanical and Structural Characterization Properties of Polyvinyl Alcohol (PVA) and Boron Based Cement Mortar

2020 ◽  
Vol 12 (2) ◽  
pp. 269-275
Author(s):  
Hakan Çağlar ◽  
Arzu Çağlar ◽  
Ömer Can
Keyword(s):  
Compressive Strength ◽  
Polyvinyl Alcohol ◽  
Cement Paste ◽  
Bending Strength ◽  
Nuclear Reactions ◽  
Strength Properties ◽  
Unit Weight ◽  
X Ray Diffraction ◽  
Environmental Disaster ◽  
Strength Tests

In this study, it was aimed to develop properties of cement paste having standard properties and produce a graphene doped Polyvinyl Alcohol (PVA) and boron-based cement paste in this context. This type of special cement is mixed with PVA as polymer additive material so it can have a higher strength and sufficient elasticity per unit weight. Also, boric acid which can absorb neutrons having poisonous effect in nuclear reactions is added into the cement in order to minimize environmental disaster caused by a nuclear accident. Compressive and bending strengths were measured based on TSE tests of graphene doped PVA and boron-based cement paste. Then, samples were measured by Brunauer-Emmett-Teller Method (BET) and subjected to X-ray Diffraction (XRD). In XRD measurements, crystalline structure was observed in all materials. According to compressive strength tests, as the graphene amount increases compressive strength also increases, however in bending strength tests as the graphene amount increases bending strength decreases. Although the values of bending strength of samples produced decreased with increase of graphene content, these values were found to be above the standard values. In addition to boron, graphene admixture has a significant effect on material with its positive strength properties.

scholarly journals Radial variation in the wood properties of Scots pine (Pinus sylvestris L.) grown on former agricultural soil

2013 ◽  
Vol 74 (2) ◽  
pp. 171-177 ◽  
Author(s):  
Arkadiusz Tomczak ◽  
Tomasz Jelonek
Keyword(s):  
Compressive Strength ◽  
Forest Soil ◽  
Scots Pine ◽  
Forest Soils ◽  
Bending Strength ◽  
Basic Density ◽  
Wood Properties ◽  
Radial Variation ◽  
Site Factors ◽  
Pine Trees

Abstract The soil of former farmland greatly differs from forest soil, and significantly influences tree growth and development compared with other site factors. The effect may also be reflected indirectly in radial variability of wood. This study compared radial variation of wood density, compressive strength along the grain and static bending strength of wood of Scots pine trees growing on former farmland and forest soils. The analyses were conducted in eight mature pine stands. On the basis of the stand description, four stands were classified as growing on forest soil (L) and four as growing on former farmland soil (P). A total of 24 model trees were selected, twelve on each soil type. Analyses of wood properties were conducted along four axes from the cross sectional radius of the trees at breast height. Our analyses showed that radial variation in wood properties of Scots pine (from selected locations in Poland) growing on former farmland is similar to the variation among the control trees growing on forest soils. In both groups of trees, the lowest density and the lowest strength were in the pith (juvenile) zone. Wood with the highest density and greatest strength was located in the central part of the radius. Wood of Scots pine trees growing on former farmland soils in comparison to that of trees growing on forest soil was characterised by a statistically lower basic density, lower compressive strength along the grain and static bending strength.

Analysis of Regression for Strength Index of Concrete Performed Brick Masonry

2013 ◽  
Vol 639-640 ◽  
pp. 803-806
Author(s):  
Qi Fang Wang
Keyword(s):  
Compressive Strength ◽  
Bending Strength ◽  
Brick Masonry ◽  
Adjustment Coefficient ◽  
Masonry Structures ◽  
Strength Index ◽  
Strength Tests ◽  
Compressive Strength Of Concrete ◽  
Basic Strength ◽  
Regressive Analysis

Based on the data of the strength tests of concrete performed brick masonry，the basic strength formulas of concrete performed brick masonry are obtained. Through regressive analysis, it will be coherent to the compressive strength of concrete performed brick masonry to introduce the adjustment coefficient of mortar contrast to the Code for Design of Masonry Structures of China. The shear strength, bending strength along straight joint and bending strength along straight joint are uniform with the Code for Design of Masonry Structures of China.

scholarly journals Effects of load types and critical molar ratios on strength properties and geopolymerization mechanism

2021 ◽  
Vol 60 (1) ◽  
pp. 216-222
Author(s):  
Tao Meng ◽  
Sara Ahmed ◽  
Dawang Dai ◽  
Yue Yu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Bending Strength ◽  
Strength Properties ◽  
Degree Of Polymerization ◽  
Molar Ratio ◽  
Molar Ratios ◽  
Loading Patterns ◽  
Load Types ◽  
The Relationship

Abstract In this study, the effect of SiO2/Al2O3 (S/A), Na2O/Al2O3 (N/A) and H2O/Na2O (H/N) molar ratios on bending and compressive strength of geopolymer were investigated. The geopolymerization mechanism was also analyzed from microstructure difference by FTIR. The experimental results showed that compressive strength and bending strength of geopolymer has an opposite reaction under different critical molar ratios. The increase of S/A molar ratio and the decrease of N/A and H/N molar ratios have resulted in an increase of the compressive strength. However, it caused a noticeable decrease in bending strength. The microstructure of geopolymer indicated that the degree of polymerization and cohesion of geopolymer have systematical depending on these critical molar ratios, making the mechanical properties of geopolymer susceptible to different types of loads. This paper reveals the relationship between the microstructure of geopolymer and different mechanical properties and helps to selectively prepare corresponding geopolymer for different loading patterns.

Multiple recycling of paperboard: Paperboard characteristics and maximum number of recycling cycles— Part I: Multiple recycling of corrugated base paper

TAPPI Journal ◽  
2019 ◽  
Vol 18 (11) ◽  
pp. 631-638
Author(s):  
FREDERIC KREPLIN ◽  
HANS-JOACHIM PUTZ ◽  
SAMUEL SCHABEL
Keyword(s):  
Compression Test ◽  
Production Capacity ◽  
Strength Properties ◽  
Paper Properties ◽  
Corrugated Board ◽  
Laboratory Conditions ◽  
Base Paper ◽  
Study Results ◽  
Short Span ◽  
Multiple Recycling

Paper for recycling is an important fiber source for the production of corrugated base paper. The change in production capacity toward more and more packaging papers affects the composition of paper for recycling and influences the paper quality. This research project investigated the influence of the multiple recycling of five different corrugated base papers (kraftliner, neutral sulfite semichemical [NSSC] fluting, corrugating medium, testliner 2, and testliner 3) on suspension and strength properties under laboratory conditions. The corrugated board base papers were repulped in a low consistency pulper and processed into Rapid-Köthen laboratory sheets. The sheets were then recycled up to 15 times in the same process. In each cycle, the suspension and the paper properties were recorded. In particular, the focus was on corrugated board-specific parameters, such as short-span compression test, ring crush test, corrugating medium test, and burst. The study results indicate how multiple recycling under laboratory conditions affects fiber and paper properties.

Sign in / Sign up

Export Citation Format

Share Document