scholarly journals The Nature of Reaction Wood

1948 ◽  
Vol 1 (1) ◽  
pp. 3 ◽  
Author(s):  
AB Wardrop ◽  
HE Dads Well

The structure of tension wood fibres is ofconsiderahle academic and practicalinterest, both in relation to considerations of the stimuli which produce them,and to studies of the influence of fibre structure on the properties of the wood asa whole. As is well known, the chief abnormal properties of tension wood lie inits unusually high longitudinal shrinkage, its high tensile strength, and its lowcompressive strength .

1955 ◽  
Vol 3 (2) ◽  
pp. 177 ◽  
Author(s):  
AB Wardrop ◽  
HE Dadswell

The cell wall organization, the cell wall texture, and the degree of lignification of tension wood fibres have been investigated in a wide variety of temperate and tropical species. Following earlier work describing the cell wall structure of tension wood fibres, two additional types of cell wall organization have been observed. In one of these, the inner thick "gelatinous" layer which is typical of tension wood fibres exists in addition to the normal three-layered structure of the secondary wall; in the other only the outer layer of the secondary wall and the thick gelatinous layer are present. In all the tension wood examined the micellar orientation in the inner gelatinous layer has been shown to be nearly axial and the cellulose of this layer found to be in a highly crystalline state. A general argument is presented as to the meaning of differences in the degree, of crystallinity of cellulose. The high degree of crystallinity of cellulose in tension wood as compared with normal wood is attributed to a greater degree of lateral order in the crystalline regions of tension wood, whereas the paracrystalline phase is similar in both cases. The degree of lignification in tension wood fibres has been shown to be extremely variable. However, where the degree of tension wood development is marked as revealed by the thickness of the gelatinous layer the lack of lignification is also most marked. Severity of tension wood formation and lack of lignification have also been correlated with the incidence of irreversible collapse in tension wood. Such collapse can occur even when no whole fibres are present, e.g. in thin cross sections. Microscopic examination of collapsed samples of tension wood has led to the conclusion that the appearance of collapse in specimens containing tendon wood can often be attributed in part to excessive shrinkage associated with the development of fissures between cells, although true collapse does also occur. Possible explanations of the irreversible shrinkage and collapse of tension wood fibres are advanced.


Alloy Digest ◽  
2020 ◽  
Vol 69 (9) ◽  

Abstract Lucefin Group C30, C30E, and C30R are medium-carbon, non-alloy steels that are used in the normalized, cold worked, or quenched and tempered condition. C30E and C30R may also be flame or induction hardened. C30, C30E, and C30R are widely used for small, moderately stressed parts, where higher strength levels are needed than can be achieved in the lower carbon grades, and also where toughness is more important than high tensile strength. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, machining, and joining. Filing Code: CS-206. Producer or source: Lucefin S.p.A.


Alloy Digest ◽  
1997 ◽  
Vol 46 (10) ◽  

Abstract Vasco 9-4-20 (0.20 wt% C) is a premium quality aircraft steel that combines high tensile strength with good fracture toughness. It is a heat-treatable alloy capable of developing an ultimate tensile strength greater than 190 ksi. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance as well as heat treating, machining, and joining. Filing Code: SA-489. Producer or source: Vasco, An Allegheny Teledyne Company.


Alloy Digest ◽  
1976 ◽  
Vol 25 (12) ◽  

Abstract NJZ Alloy No. 55 is a zinc-cadmium alloy characterized by high tensile strength and hardness but low ductility. It has high stiffness and resiliency but low drawing and forming characteristics. Its applications include hardware and medallions. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as creep and fatigue. It also includes information on corrosion resistance as well as casting, forming, heat treating, machining, and joining. Filing Code: Zn-30. Producer or source: New Jersey Zinc Company.


ACS Omega ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 2890-2898
Author(s):  
Xiaojiao Jiao ◽  
Jiangling Liu ◽  
Jing Jin ◽  
Fei Cheng ◽  
Yunxin Fan ◽  
...  

2015 ◽  
Vol 1134 ◽  
pp. 56-60 ◽  
Author(s):  
Siti Aisyah Jarkasi ◽  
Dzaraini Kamarun ◽  
Azemi Samsuri ◽  
Amir Hashim Md Yatim

Fillers play important roles in enhancing mechanical properties of NR latex films. The effect of filler dispersion and amount of dispersing agent to the tensile strength and tearing energy of NR latex films were investigated in this study. The studies were carried out by (i) varying the amount of dispersing agent (Anchoid) added which is an anionic surfactant; and (ii) varying the speed of stirring during mixing of latex with compounding ingredients. It was observed that tensile strength and tearing energy were affected by both factors listed. In the case of NR latex film filled with 10 pphr of carbon black (Super Abrasion Furnace, SAF), the optimum stirring speed was 400 rpm and the optimum amount of surfactant was in the range of 5 to 10 % by weight. High tensile strength ranging from 29 - 31 MPa and high tearing energies ranging from 90.6 - 111.0 kJ/m2were achieved from optimization of these two factors; rendering their importance.


2018 ◽  
Vol 122 (1255) ◽  
pp. 1352-1370 ◽  
Author(s):  
H. Liu ◽  
B.G. Falzon ◽  
G. Catalanotti ◽  
W. Tan

ABSTRACTCarbon fibres with high tensile strength are being increasingly utilised in the manufacture of advanced composite aerostructures. A Modified Compact Tension (MCT) specimen is often deployed to measure the longitudinal intralaminar fracture toughness but a high tensile strength often leads to premature damage away from the crack tip. We present an approach whereby the MCT specimen is supported by external fixtures to prevent premature damage. In addition, we have developed a novel measurement technique, based on the fibre failure strain and C-scanning, to determine the crack length in the presence of surface sublaminate delamination which masks the crack tip location. A set of cross-ply specimens, with a ((90/0)s)4 layup, were manufactured from an IMS60/epoxy composite system Two different data reduction schemes, compliance calibration and the area method, are used to determine the fibre-dominated initiation and propagation intralaminar fracture toughness values. Propagation values of fracture toughness were measured at 774.9 ± 5.2% kJ/m2 and 768.5 ± 4.1% kJ/m2, when using the compliance calibration method and the area method, respectively. Scanning Electron Microscopy (SEM) is carried out on the fracture surface to obtain insight into the damage mechanism of high-tensile-strength fibre-reinforced unidirectional composites. The measured tensile fracture toughness value is used in a fully validated computational model to simulate the physical test.


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