Transverse mechanical behaviour and moisture absorption of waterlogged archaeological wood from the Vasa ship

Holzforschung ◽  
2007 ◽  
Vol 61 (3) ◽  
pp. 279-284 ◽  
Author(s):  
Jonas Ljungdahl ◽  
Lars A. Berglund
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Mechanical Behaviour ◽  
Moisture Absorption ◽  
Deformation Mechanisms ◽  
Support Structure ◽  
Archaeological Wood ◽  
Waterlogged Archaeological Wood ◽  
Tangential Stiffness ◽  
Compressive Loads

Abstract Damage on the hull of the 17th century Swedish warship Vasa has been observed recently. Damage in the form of indentations in the wood is caused by high compressive loads from the support structure. In the process of developing an improved support structure, radial mechanical properties and the deformation mechanisms of Vasa oak are particularly important. Causes of differences in PEG content and oak degradation are also of interest. The radial modulus and compressive strength of Vasa oak are 50% lower than for recent oak. Furthermore, a significant change in failure mechanism is observed. More brittle separation fracture of the rays of Vasa oak is observed compared to the continuous folds of rays in recent oak. Tangential stiffness and strength are also 30% and 50% lower, respectively. Comparably small differences in moisture absorption between PEG-extracted Vasa oak and recent oak indicate a low extent of degradation of the Vasa oak.

Towards improved understanding of PEG-impregnated waterlogged archaeological wood: A model study on recent oak

Holzforschung ◽  
2010 ◽  
Vol 64 (2) ◽  
Author(s):  
Ingela Bjurhager ◽  
Jonas Ljungdahl ◽  
Lennart Wallström ◽  
E. Kristofer Gamstedt ◽  
Lars A. Berglund
Keyword(s):  
Mechanical Properties ◽  
Microfibril Angle ◽  
Mechanical Tests ◽  
Chemical Degradation ◽  
Cellulose Microfibrils ◽  
Radial Compression ◽  
Biological Degradation ◽  
Archaeological Wood ◽  
Waterlogged Archaeological Wood ◽  
The Impact

Abstract To prevent deformation and cracking of waterlogged archaeological wood, polyethylene glycol (PEG) as a bulk impregnation agent is commonly applied. PEG maintains the wood in a swollen state during drying. However, swelling of wood can reduce its mechanical properties. In this study, the cellular structure of oak and cell wall swelling was characterized by scanning electron microscopy (SEM) of transverse cross-sections, and the microfibril angle of oak fibers was determined by wide angle X-ray scattering (WAXS). Samples of recent European oak (Quercus robur L) impregnated with PEG (molecular weight of 600) were tested in axial tension and radial compression. Mechanical tests showed that axial tensile modulus and strength were only slightly affected by PEG, whereas radial compressive modulus and yield strength were reduced by up to 50%. This behavior can be explained by the microstructure and deformation mechanisms of the material. Microfibril angles in tensile test samples were close to zero. This implies tensile loading of cellulose microfibrils within the fiber cell walls without almost any shear in the adjacent amorphous matrix. These results are important because they can help separate the impact of PEG on mechanical properties from that of chemical degradation in archaeological artifacts, which display only small to moderate biological degradation.

Fabrication of water-soluble loose-fill foam from tamarind (Tamarindus indica L.) seed polysaccharide by mechanical frothing and freeze-drying process

2020 ◽  
pp. 0021955X2094856
Author(s):  
Ladawan Songtipya ◽  
Ponusa Songtipya ◽  
Thummanoon Prodpran ◽  
Ekwipoo Kalkornsurapranee ◽  
Jobish Johns
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Freeze Drying ◽  
Moisture Absorption ◽  
Cell Structure ◽  
Water Soluble ◽  
Drying Process ◽  
Uniform Size ◽  
Cell Window ◽  
Loose Fill

The water-soluble loose-fill foam obtained from tamarind seed polysaccharide (TSP) was successfully prepared by a combination of mechanical frothing and freeze-drying process. The effects of TSP concentration, plasticizer content, and surfactant content on the cellular morphology, physical properties, mechanical properties, and moisture absorption were investigated. The cellular structure of TSP foam exhibited an open cell structure with a non-uniform size of the cell window, and the density varied in a range of ∼0.006–0.106 g/cm3. Foam preparation with high TSP concentration, low plasticizer as well as glycerol content enhanced the mechanical properties of the obtained foam, including tensile strength, compressive strength, and hardness. The high compressive strength of TSP foams up to ∼1.03 MPa can be produced which demonstrates that TSP foam is capable to use as a loose-fill product.

scholarly journals EXPERIMENTAL STUDY ON THE MECHANICAL BEHAVIOUR OF FIRED SAND-CLAY AND GLASS POWDER-CLAY BRICKS

2021 ◽  
Vol 27 (1) ◽  
pp. 4-10
Author(s):  
Adeolu Adediran ◽  
Abayomi Akinwande ◽  
Oluwatosin Balogun ◽  
Olanrewaju Adesina ◽  
Adeniyi Olayanju
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Mechanical Behaviour ◽  
Glass Powder ◽  
Flexural Modulus ◽  
Fine Sand ◽  
Clay Bricks ◽  
Waste Glass Powder ◽  
Fired Bricks ◽  
Compressive And Flexural Strengths

Mechanical behaviour of fired bricks containing varied amount of fine sand (FS) and waste glass powder (GP) was investigated. FS and GP were added to bricks at varied amount of 0, 5, 10, 15, 20, 25, 30, 35 and 40 wt. %. Firing was done at 1200 ⁰C and samples produced were evaluated for compressive and flexural strengths while microstructural analyses of 25 wt. % FS and GP-clay bricks were examined. Results showed that compressive strength was highest at 30 wt. % GP for GP-bricks while for FS-clay bricks, compressive strength rose to 35 and 40 wt. % FS addition.  Flexural strength for GP-clay and FS-clay bricks peaked at 30 wt. % GP (3.63 MPa) and 40 wt % FS (2.45) respectively. Flexural modulus increased progressively and exponentially as FS and GP proportion increased. Workdone in resisting deformation and deflection during bending reduced with increased amount of both additives. Flexural strain was inversely related to load and stiffness. In conclusion, addition of GP and FS in increasing amount resulted in improved mechanical properties in the bricks. Also, increased proportion of GP and FS was found to improve response to loading in fired bricks.

Effect of combined drink cans and steel fibers on the impact resistance and mechanical properties of concrete

2020 ◽  
Vol 14 (2) ◽  
pp. 6734-6742
Author(s):  
A. Syamsir ◽  
S. M. Mubin ◽  
N. M. Nor ◽  
V. Anggraini ◽  
S. Nagappan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Impact Resistance ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Indirect Tensile ◽  
The Impact

This study investigated the combine effect of 0.2 % drink cans and steel fibers with volume fractions of 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3% to the mechanical properties and impact resistance of concrete. Hooked-end steel fiber with 30 mm and 0.75 mm length and diameter, respectively was selected for this study.  The drinks cans fiber were twisted manually in order to increase friction between fiber and concrete. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the strength performance of concrete, especially the compressive strength, flexural strength and indirect tensile strength. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the compressive strength, flexural strength and indirect tensile strength by 2.3, 7, and 2 times as compare to batch 1, respectively. Moreover, the impact resistance of fiber reinforced concrete has increase by 7 times as compared to non-fiber concretes. Moreover, the impact resistance of fiber reinforced concrete consistently gave better results as compared to non-fiber concretes. The fiber reinforced concrete turned more ductile as the dosage of fibers was increased and ductility started to decrease slightly after optimum fiber dosage was reached. It was found that concrete with combination of 2% steel and 0.2% drink cans fibers showed the highest compressive, split tensile, flexural as well as impact strength.    

PEMANFAATAN KAYU AKASIA MANGIUM (Acacia mangium Willd) UNTUK MEBEL

2012 ◽  
Vol 4 (1) ◽  
pp. 1
Author(s):  
Djoko Purwanto
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Physical Properties ◽  
Treatment Process ◽  
Acacia Mangium ◽  
Physical And Mechanical Properties ◽  
Wood Fibers ◽  
Test Parameters ◽  
Mechanical And Physical Properties ◽  
Scale Scores

Timber Acacia mangium (Acacia mangium, Willd) for Furniture. The study aims to determine the mechanical and physical properties and the decorative value (color and fiber) wood of acacia mangium with using finishing materials. This type of finishing material used is ultran lasur natural dof ,ultran lasur classic teak, aqua politur clear dof, aqua politur akasia dan aqua politur cherry. After finishing the wood is stored for 3 months. Test parameters were observed, namely, physical and mechanical properties of wood, adhesion of finishing materials, color and appearance of the fiber, and timber dimensions expansion. The results showed that the mechanical physical properties of acacia wood qualified SNI. 01-0608-89 about the physical and mechanical properties of wood for furniture, air dry the moisture content from 13.78 to 14.89%, flexural strength from 509.25 to 680.50 kg/cm2, and compressive strength parallel to fiber 342.1 - 412.9 kg/cm2. Finishing the treatment process using five types of finishing materials can increase the decorative value (color and fiber) wood. Before finishing the process of acacia mangium wood has the appearance of colors and fibers and less attractive (scale scores 2-3), after finishing acacia wood fibers have the appearance of colors and interesting and very interesting (scale 4-5).Keywords: mangium wood, mechanical properties, decorative value, finishing, furniture.

Incorporation of Iraqi Rocks in the Production of Eco-Friendly Cement Mortar

2020 ◽  
Vol 38 (10A) ◽  
pp. 1522-1530
Author(s):  
Rawnaq S. Mahdi ◽  
Aseel B. AL-Zubidi ◽  
Hassan N. Hashim
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Water Absorption ◽  
Structural Properties ◽  
Mechanical Milling ◽  
Cement Mortar ◽  
Cement Mortars

This work reports on the incorporation of Flint and Kaolin rocks powders in the cement mortar in an attempt to improve its mechanical properties and produce an eco-friendly mortar. Flint and Kaolin powders are prepared by dry mechanical milling. The two powders are added separately to the mortars substituting cement partially. The two powders are found to improve the mechanical properties of the mortars. Hardness and compressive strength are found to increase with the increase of powders constituents in the cement mortars. In addition, the two powders affect water absorption and thermal conductivity of the mortar specimens which are desirable for construction applications. Kaolin is found to have a greater effect on the mechanical properties, water absorption, and thermal conductivity of the mortars than Flint. This behavior is discussed and analyzed based on the compositional and structural properties of the rocks powders.

scholarly journals Mechanical Behavior of Brick Masonry in an Acidic Atmospheric Environment

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2694 ◽  
Author(s):  
Shansuo Zheng ◽  
Lihua Niu ◽  
Pei Pei ◽  
Jinqi Dong
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Acid Rain ◽  
Cement Mortar ◽  
Brick Masonry ◽  
Atmospheric Environment ◽  
Peak Strain ◽  
Lime Mortar ◽  
Attenuation Model

In order to evaluate the deterioration regularity for the mechanical properties of brick masonry due to acid rain corrosion, a series of mechanical property tests for mortars, bricks, shear prisms, and compressive prisms after acid rain corrosion were conducted. The apparent morphology and the compressive strength of the masonry materials (cement mortar, cement-lime mortar, cement-fly ash mortar, and brick), the shear behavior of the masonry, and the compression behavior of the masonry were analyzed. The resistance of acid rain corrosion for the cement-lime mortar prisms was the worst, and the incorporation of fly ash into the cement mortar did not improve the acid rain corrosion resistance. The effect of the acid rain corrosion damage on the mechanical properties for the brick was significant. With an increasing number of acid rain corrosion cycles, the compressive strength of the mortar prisms, and the shear and compressive strengths of the brick masonry first increased and then decreased. The peak stress first increased and then decreased whereas the peak strain gradually increased. The slope of the stress-strain curve for the compression prisms gradually decreased. Furthermore, a mathematical degradation model for the compressive strength of the masonry material (cement mortar, cement-lime mortar, cement-fly ash mortar, and brick), as well as the shear strength attenuation model and the compressive strength attenuation model of brick masonry after acid rain corrosion were proposed.

scholarly journals Experimental Analysis of the Mechanical Properties and Resistivity of Tectonic Coal Samples with Different Particle Sizes

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2303
Author(s):  
Congyu Zhong ◽  
Liwen Cao ◽  
Jishi Geng ◽  
Zhihao Jiang ◽  
Shuai Zhang
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Uniaxial Compressive Strength ◽  
Coalbed Methane ◽  
Coal Sample ◽  
Fine Particles ◽  
Particle Sizes ◽  
Tectonic Coal

Because of its weak cementation and abundant pores and cracks, it is difficult to obtain suitable samples of tectonic coal to test its mechanical properties. Therefore, the research and development of coalbed methane drilling and mining technology are restricted. In this study, tectonic coal samples are remodeled with different particle sizes to test the mechanical parameters and loading resistivity. The research results show that the particle size and gradation of tectonic coal significantly impact its uniaxial compressive strength and elastic modulus and affect changes in resistivity. As the converted particle size increases, the uniaxial compressive strength and elastic modulus decrease first and then tend to remain unchanged. The strength of the single-particle gradation coal sample decreases from 0.867 to 0.433 MPa and the elastic modulus decreases from 59.28 to 41.63 MPa with increasing particle size. The change in resistivity of the coal sample increases with increasing particle size, and the degree of resistivity variation decreases during the coal sample failure stage. In composite-particle gradation, the proportion of fine particles in the tectonic coal sample increases from 33% to 80%. Its strength and elastic modulus increase from 0.996 to 1.31 MPa and 83.96 to 125.4 MPa, respectively, and the resistivity change degree decreases. The proportion of medium particles or coarse particles increases, and the sample strength, elastic modulus, and resistivity changes all decrease.

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