scholarly journals Some Physical Processes Involved in Deformation and Fracture

2021 ◽  
Author(s):  
◽  
Walter James Cousins
Keyword(s):  
Moisture Content ◽  
Cellular Level ◽  
Transverse Fracture ◽  
Microscopical Examination ◽  
Physical Processes ◽  
Fracture Properties ◽  
Longitudinal Splitting ◽  
Transverse Tension ◽  
Deformation And Fracture ◽  
Scanning Electron

<p>The effects of strain rate, of moisture content, and of tracheid structure on the transverse fracture properties of Pinus Radiata have been studied. Small rectangular blocks were loaded to failure in transverse tension, with the conditions of fracture being varied as follows: (i) strain raite - at 2 x 10 caret-6 sec caret-1, and from 10 caret-5 to 10 caret 2 sec caret-1 in decade steps , (ii) moisture content - airdry (12.7%) and saturated, and (iii) structure - springwood and summerwood. Microscopical examination (both scanning electron and optical) of the surfaces produced by the facture showed that the cellular level, either of two types of failure could occur. These are called transwall and intrawall; transwall is the longitudinal splitting of a tracheid wall, and intrawall is a splitting between adjacent tracheids.</p>

scholarly journals Some Physical Processes Involved in Deformation and Fracture

2021 ◽  
Author(s):  
◽  
Walter James Cousins
Keyword(s):  
Moisture Content ◽  
Cellular Level ◽  
Transverse Fracture ◽  
Microscopical Examination ◽  
Physical Processes ◽  
Fracture Properties ◽  
Longitudinal Splitting ◽  
Transverse Tension ◽  
Deformation And Fracture ◽  
Scanning Electron

<p>The effects of strain rate, of moisture content, and of tracheid structure on the transverse fracture properties of Pinus Radiata have been studied. Small rectangular blocks were loaded to failure in transverse tension, with the conditions of fracture being varied as follows: (i) strain raite - at 2 x 10 caret-6 sec caret-1, and from 10 caret-5 to 10 caret 2 sec caret-1 in decade steps , (ii) moisture content - airdry (12.7%) and saturated, and (iii) structure - springwood and summerwood. Microscopical examination (both scanning electron and optical) of the surfaces produced by the facture showed that the cellular level, either of two types of failure could occur. These are called transwall and intrawall; transwall is the longitudinal splitting of a tracheid wall, and intrawall is a splitting between adjacent tracheids.</p>

scholarly journals Dependence of Microcrack Behavior in Wood on Moisture Content during Drying

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Hiroyuki Yamamoto ◽  
Hiroki Sakagami ◽  
Yoshio Kijidani ◽  
Junji Matsumura
Keyword(s):  
Electrical Resistivity ◽  
Moisture Content ◽  
Wood Surface ◽  
Laser Scanning ◽  
Measurement Range ◽  
Cellular Level ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Sequential Images

A modified confocal laser scanning microscopy (CLSM) system was developed not only to observe the microcracks on the surface ofCryptomeria japonicaD. Donin situat the cellular level but also to obtain information about the moisture content (MC) of the wood surface by measuring the change in its electrical resistivity. The sequential images and changes in the electrical resistivity of the wood surface indicated that microcracks formed between the tracheid and ray parenchyma in the latewood region at >1.0E+ 07 Ω/sq (square). Microcracks formed when the MC of the wood surface was below the fiber saturation point determined through regression analysis of the surface electrical resistivity and MC. Most of the microcracks develop when the surface electrical resistivity ranged from 3.95E+ 10 to 3.60E+ 12 Ω/sq. When the surface MC was~2.5%, microcracks closed and the surface electrical resistivity was either~1.00E+ 15 Ω/sq or outside the measurement range. The modified CLSM and the method to measure the MC of the wood surface can be used to acquire information about the surface MC in specific areas shown in CLSM images. The findings indicated that the MC of the surface of the wood plays an important role in suppressing the emergence of microcracks in drying wood. The modified CLSM system and the method of measuring the MC of the surface of wood can be used to efficiently evaluate methods of drying wood and the quality of dried wood.

Philometroides acanthopagri sp. nov., a new philometrid (Nematoda, Philometridae) from the musculature of Acanthopagrus latus (Sparidae) from marine waters of Iraq

2012 ◽  
Vol 57 (4) ◽  
Author(s):  
František Moravec ◽  
Abdul Jassim ◽  
Nadrah Al-Salim
Keyword(s):  
New Species ◽  
Arabian Gulf ◽  
Nematode Species ◽  
Microscopical Examination ◽  
Marine Waters ◽  
Pectoral Fins ◽  
Electron Microscopical ◽  
Acanthopagrus Latus ◽  
Southern Iraq ◽  
Scanning Electron

AbstractA new nematode species, Philometroides acanthopagri sp. nov. (Philometridae), is described from gravid and subgravid specimens found in the musculature near pectoral fins and in nasal cavity of the yellowfin seabream Acanthopagrus latus (Houttuyn) (Sparidae, Perciformes) from marine waters off the coast of southern Iraq. Based on light and scanning electron microscopical examination, the new species differs from its congeners in a combination of morphological and biometrical features. It is the first species of Philometroides reported from a sparid fish and the first representative of this genus recorded from fishes in the Arabian Gulf. A key to Philometroides species parasitizing marine and brackish-water fishes is provided.

Observations on a field outbreak of Pox Virus Infection in young Nile crocodiles (Crocodylus Niloticus)

1991 ◽  
Vol 62 (1) ◽  
pp. 26-29 ◽  
Author(s):  
F. W. Huchzermeyer ◽  
K. D.A. Huchzermeyer ◽  
J. F. Putterill
Keyword(s):  
Virus Infection ◽  
Histopathological Examination ◽  
Skin Lesions ◽  
High Morbidity ◽  
Microscopical Examination ◽  
Virus Particles ◽  
Large Numbers ◽  
Intracytoplasmic Inclusions ◽  
Electron Microscopical ◽  
Scanning Electron

A field outbreak of pox virus infection in juvenile Nile crocodiles (Crocodylus niloticus), in which high morbidity and negligible mortality occurred, is described. Histopathological examination of the skin lesions revealed numerous large intracytoplasmic inclusions in the dermis and a very mild dermal inflammatory reaction. Scanning electron microscopical examination of the skin revealed the presence of large numbers of virus particles in the inclusions. Skin lesions persisted for 5 to 6 months.

Fracture Properties of Human Enamel and Dentin

1976 ◽  
Vol 55 (1) ◽  
pp. 154-164 ◽  
Author(s):  
Stephen T. Rasmussen ◽  
Robert E. Patchin ◽  
David B. Scott ◽  
Arthur H. Heuer
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Fracture Behavior ◽  
Brittle Materials ◽  
Dentinal Tubules ◽  
Fracture Properties ◽  
Human Enamel ◽  
Scanning Electron Microscope Fractographs ◽  
Work Of Fracture ◽  
Scanning Electron

Work of fracture measurements and scanning electron microscope fractographs show that both enamel and dentin can best be considered as brittle materials with anisotropic fracture properties. Enamel is highly anisotropic, with the weakest path of fracture parallel to the enamel rods. Dentin is less anisotropic, with easiest fracture perpendicular to the dentinal tubules. A model is proposed to explain the fracture behavior of enamel.

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