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.

scholarly journals Essential Oils as Alternative Biocides for the Preservation of Waterlogged Archaeological Wood

2020 ◽  
Vol 8 (12) ◽  
pp. 2015
Author(s):  
Federica Antonelli ◽  
Marco Bartolini ◽  
Marie-Laure Plissonnier ◽  
Alfonso Esposito ◽  
Giulia Galotta ◽  
...  
Keyword(s):  
Essential Oils ◽  
Inhibitory Concentration ◽  
Treated Wood ◽  
Biological Degradation ◽  
Archaeological Wood ◽  
Waterlogged Archaeological Wood ◽  
Materials Used ◽  
And Storage ◽  
Generation Sequencing

Waterlogged archaeological wood is exposed to a high risk of biological degradation during the post-excavation phases of storage and restoration. For this reason, often biocides must be used to preserve wooden remains. In the present work three essential oils (cinnamon, wild thyme, and common thyme) were tested as possible alternative biocides to use in the preservation of waterlogged archaeological wood. The oils were first tested in vitro to establish the minimum inhibitory concentration (MIC) and to evaluate the biocidal activity on selected fungal strains. Then, the established MIC was applied on waterlogged archaeological wood samples and during an actual restoration treatment. The effectiveness of the oils was evaluated through cultural analyses, ATP quantification, and next-generation sequencing. The results showed that the oils caused a significant decrease in the vitality of fungal mycelia grown in vitro and of the microbiota present in treated wood and storage water. Furthermore, an influence on the composition of the bacterial communities of treated wood samples was observed. Although further tests are needed to evaluate interferences with the materials used during restoration procedures, essential oils could be considered as a possible alternative to the currently used biocide.

Research on the Flow Characteristics of Polymer Injection Molding under Ultrasonic Vibration and Plastics’ Mechanical Strength

2010 ◽  
Vol 37-38 ◽  
pp. 1092-1100
Author(s):  
Ji Bin Li ◽  
Ke Ke Xu ◽  
Xin Bo Lin ◽  
Xiao Yu Wu ◽  
Guo Li Gao
Keyword(s):  
Mechanical Properties ◽  
Injection Molding ◽  
Ultrasonic Vibration ◽  
Flow Characteristics ◽  
Mechanical Tests ◽  
Impact Testing ◽  
Melt Flow Rate ◽  
Polymer Injection ◽  
Molding Method ◽  
The Impact

In this paper, ultrasonic vibration is adopted and exerted on injection molding in order to improve plastics’ forming ability, and the impact testing is used to analyze different injection parts’ mechanical properties. On the one hand, experiments prove that ultrasonic vibration can increase polymer’s melt flow rate, decrease melt viscosity, and improve injection flowing in mould cavity. On the other hand, the mechanical tests prove that the ultrasonic vibration can improve plastics’ tensile strength, elastic modulus and other mechanical properties. As a result, a weldless ultrasound-assisted injection molding method is recommended.

scholarly journals Some Mechanical Properties of Experimental Mg-Al -RE-Mn Magnesium Alloys

2014 ◽  
Vol 14 (1) ◽  
pp. 13-16 ◽  
Author(s):  
K.N. Braszczyńska-Malik
Keyword(s):  
Mechanical Properties ◽  
Rare Earth ◽  
Impact Strength ◽  
Rare Earth Elements ◽  
Mass Fraction ◽  
Brinell Hardness ◽  
Mechanical Tests ◽  
Gravity Casting ◽  
Compression Properties ◽  
The Impact

Abstract The results of some mechanical properties of four Mg-5Al-xRE-0.4Mn (x = 1 - 5) alloys are presented. The microstructure of experimental alloys consisted of an α-Mg phase and an α+γ semi-divorced eutectic, Al11RE3 phase and an Al10RE2Mn7 intermetallic compound. For gravity casting in metal mould alloys, Brinell hardness, impact strength, tensile and compression properties at ambient temperature were determined. The performed mechanical tests allowed the author to determine the proportional influence of the mass fraction of rare earth elements in the alloys on their tensile strength, yield strength, compression strength and Brinell hardness. The impact strength of the alloys slightly decreases with a rise in the rare earth elements mass fraction.

scholarly journals Reinforcing polypropylene with calcium carbonate of different morphologies and polymorphs

2018 ◽  
Vol 25 (4) ◽  
pp. 745-751 ◽  
Author(s):  
Yanwei Jing ◽  
Xueying Nai ◽  
Li Dang ◽  
Donghai Zhu ◽  
Yabin Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Calcium Carbonate ◽  
Mechanical Tests ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Crystallization Property ◽  
Reinforced Composite ◽  
Treated Sample ◽  
The Impact

Abstract The influence of calcium carbonate (CaCO3) with different polymorphs (calcite and aragonite) and morphologies (granular and rod-like) on mechanical and crystallization properties of polypropylene (PP) was investigated. Meanwhile, these CaCO3 fillers coated with oleic acid were added in different contents to PP. The results indicate that the tensile strength, flexural strength, modulus, and crystallization property of the filler-treated samples are improved, but the impact strength decreased. The crystallinity of the composites is higher than that of neat PP. Moreover, in the rod shape filler-treated sample, in both whisker species, the mechanical properties of composites are superior to the particles filled. Differential scanning calorimetry, X-ray diffraction, and mechanical tests display that calcite whisker-reinforced composite has higher crystallization enthalpy, melting enthalpy, degree of crystallinity, and mechanical properties than aragonite whiskers and calcite particles filled composites.

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.

Flamanville EPR RPV’s Heads Carbon Segregation: Tests Program Definition to Characterize the Mechanical Properties of the Carbon Segregation

2018 ◽  
Author(s):  
Stéphane Marie ◽  
Jérôme Demarecaux ◽  
Philippe Fichot ◽  
Elisabeth Keim ◽  
Johannes May ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Content ◽  
Mechanical Tests ◽  
Main Issue ◽  
Residual Carbon ◽  
Testing Program ◽  
Carbon Segregation ◽  
Brittle To Ductile Transition ◽  
Drop Weight ◽  
The Impact

To characterize the mechanical properties of the residual carbon segregation of the Flamanville EPR RPV heads, a testing program have been organized by Framatome and performed in 3 laboratories (Wood, Framatome technical center of Erlangen and SCK Mol). This paper presents the tests program, how it has been defined and its goals. The main issue was the impact of the carbon content on the toughness properties. A procedure was defined to characterize specifically the toughness distribution in the upper part of the brittle-to-ductile transition. The ductile regime was also investigated. These tests were completed with tensile, Charpy and drop weight tests, representing a final total of approximatively 1700 mechanical tests.

Analysis of the Mechanical Properties of Pristine and Thermally Aged PC/PMMA Micro and Nanolayered Films

2010 ◽  
Author(s):  
Hui Shen ◽  
N. D. Gannon
Keyword(s):  
Mechanical Properties ◽  
Film Thickness ◽  
Polymer Films ◽  
Thermal Aging ◽  
Layered Structures ◽  
Mechanical Tests ◽  
Hierarchical Systems ◽  
Process Technology ◽  
Barrier Materials ◽  
The Impact

Microlayered polymer films are synthetic polymers with biomimicking layered structures which have been successfully commercialized. Nanolayered polymer films have been developed in recent years using advanced process technology. The innovative nanolayered polymer films have more complex hierarchical systems with truly biomimic nature. There are many potential applications for the nanolayered films such as gas barrier materials and spherical gradient refractive index lens. However, as polymers possess many properties that are different from metals and other traditional materials, the mechanical properties of the polymer films can vary widely depending on the material formulation, environmental temperature, and time. In this work, standard mechanical tests have been conducted to study the relationship between the mechanical properties and the layered structures. The impact of thermal aging on the mechanical behavior of the micro and nanolayered polymer films has also been investigated experimentally. The composition of the polymer films under study are 50vol% polycarbonate (PC) and 50vol% poly(methyl methacrylate) (PMMA). The layer thickness ranges from 31 nm to 32 μm and the film thickness 50.8 μm to 254 μm. These films were thermally aged at 115°C and 125°C in a constant temperature oven for up to four weeks. The mechanical properties, including the modulus of elasticity, tensile strength and ductility, have been tested on the pristine and thermally aged films. It has been observed that the mechanical properties of the films vary with the layered structure and film thickness. The thermal aging temperature and aging time have significant effects on the overall character of the stress-strain responses. Films with different thicknesses and layer formations respond to the thermal conditions differently.

scholarly journals Investigation on Mechanical Properties of Graphene Reinforced Jute Fibre Reinforced Polymer Composites

2020 ◽  
Author(s):  
Rathinasabapathi G ◽  
Krishnamoorthy A
Keyword(s):  
Mechanical Properties ◽  
Fatigue Strength ◽  
Impact Strength ◽  
Mechanical Tests ◽  
Layered Composite ◽  
Fiber Reinforced Polymer ◽  
Jute Fibre ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
The Impact

In this study, the impact of adding Graphene Nano Platelets on the mechanical properties of Jute Fiber reinforced Polymer (JFRP) composites has been investigated. JFRP composite specimens were fabricated with varying number of layers (3 Layers, 4 Layers, and 5 Layers) and different orientations (30 degree, 45 degree, 60 degree) reinforced with 2% weight graphene nano platelet. Ultrasonicator is used for dispersion of graphene nano platelets into the epoxy matrix. Mechanical Tests namely Tensile test, flexural test and impact test is carried out to study the behavior of JFRP with different layers and orientations. The results proved that the use of 2% weight of Graphene Nano platelets led an enhancement in fatigue strength and impact strength. Also it is found that 3 layered with 30 degree orientation composite specimens had better mechanical properties compared to 4 layered and 5 layered composite specimens.

scholarly journals Thermal and Mechanical Assessment of PLA-SEBS and PLA-SEBS-CNT Biopolymer Blends for 3D Printing

2021 ◽  
Vol 11 (13) ◽  
pp. 6218
Author(s):  
Balázs Ádám ◽  
Zoltán Weltsch
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Mechanical Tests ◽  
The Other ◽  
Raw Material ◽  
Bending Test ◽  
Thermal And Mechanical Properties ◽  
Scanning Calorimetry ◽  
Partial Fracture ◽  
The Impact

Polylactic acid (PLA) is one of the most promising biopolymers often used as a raw material in 3D printing in many industrial areas. It has good mechanical properties, is characterized by high strength and stiffness, but unfortunately, it has some disadvantages; one is brittleness, and the other is slow crystallization. Amounts of 1–5% SEBS (styrene-ethylene-butylene-styrene) thermoplastic elastomer were blended into the PLA and the thermal and mechanical properties were investigated. DSC (Differential Scanning Calorimetry) measurements on the filaments have shown that SEBS increases the initial temperature of crystallization, thereby acting as a nucleating agent. The cooling rate of 3D printing, on the other hand, is too fast for PLA, so printed specimens behave almost amorphously. The presence of SEBS increases the impact strength, neck formation appears during the tensile test, and in the bending test, the mixture either suffers partial fracture or only bends without fracture. Samples containing 1% SEBS were selected for further analysis, mixed with 0.06 and 0.1% carbon nanotubes (CNTs), and tested for thermal and mechanical properties. As a result of CNTs, another peak appeared on the DSC curve in addition to the original single-peak crystallization, and the specimens previously completely broken in the mechanical tests suffered partial fractures, and the partially fractured pieces almost completely regained their original shape at the end of the test.

scholarly journals Mechanical Properties and Microstructure of the Repeated Weld-Repairs of Austenitic Stainless Steel Plates

2019 ◽  
Vol 269 ◽  
pp. 01010
Author(s):  
W. Winarto ◽  
M. Anis ◽  
Refnaldi
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Manufacturing Industry ◽  
Substantial Reduction ◽  
Mechanical Tests ◽  
Steel Plates ◽  
304L Stainless Steel ◽  
Weld Repair ◽  
The Impact

Joining Most of the repair weld of parts and components cannot be avoided in any manufacturing industry. Weld procedure is commonly used to ensure the welded parts can be useful and safe. Weld repairs have to be carried out with suitable care and avoid premature failures of the weld components. The weld repairs often occur repeatedly on welded parts. Hence the investigation was done to evaluate the effects of repeated weld-repairs of austenitic stainless steels plates on both mechanical and microstructural properties. Weld samples were joined using gas tungsten arc welding (GTAW) with several numbers of weld repairs. The first weld was performed to join metal plates and assigned as 0R. The weld bead was then ground away and followed by the first weld repair using the same GTAW (designated as 1R). This repair process was continual until five times (identified as 5R). All specimen was characterized by the chemical composition test, the microstructure observation, and the mechanical tests. It was found that the HAZ hardness of repeated weld repair decreased when the number of repairs increased. The tensile test results of the repeated weld repair had a few effects on tensile strength. However, the result of the impact test on repeated weld repairs shows a substantial reduction in the toughness properties as the repeated number of weld repairs. The repeated weld repair influenced the mechanical properties of austenitic stainless steel plates and showed a tremendous decrease compared with the type of 304L stainless steel as the repeated numbers of weld repairs.

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