Effect of structural factors on the kinetics of fatigue cracks in constructional steels

1978 ◽  
Vol 14 (2) ◽  
pp. 113-123 ◽  
Author(s):  
O. N. Romaniv ◽  
Ya. N. Gladkii ◽  
Yu. V. Zima
Keyword(s):  
Fatigue Cracks ◽  
Structural Factors ◽  
Kinetics Of

Investigation and modeling of the kinetics of the development of corrosion-fatigue cracks

1978 ◽  
Vol 13 (3) ◽  
pp. 235-239
Author(s):  
N. N. Vasserman ◽  
V. A. Merkushev ◽  
M. S. Nemanov
Keyword(s):  
Corrosion Fatigue ◽  
Fatigue Cracks ◽  
Kinetics Of

Structural effects on epimerization of bacteriochlorophyll a and chlorophyll a revealed using 3-acetyl chlorophyll a

2020 ◽  
Vol 24 (04) ◽  
pp. 499-504 ◽  
Author(s):  
Yoshitaka Saga ◽  
Shiori Nakagawa
Keyword(s):  
Physicochemical Properties ◽  
Chlorophyll A ◽  
Photosynthetic Reaction Center ◽  
Molecular Structures ◽  
Structural Factors ◽  
Structural Effects ◽  
Photosynthetic Organisms ◽  
Acetyl Group ◽  
Kinetics Of

Chlorophyll (Chl) and bacteriochlorophyll (BChl) pigments, which are crucial cyclic tetrapyrroles in photosynthesis, generally have a chiral center in their exo-cyclic five-membered E-ring. Although [Formula: see text]-epimers (primed-type) of (B)Chl pigments are rarely present in photosynthetic organisms, they play key roles in photosynthetic reaction center complexes. The epimerization mechanism of (B)Chl pigments in vivo has not been unraveled. The structural effects on the physicochemical properties of (B)Chl epimerization reactions provide useful information to tackle this question. We analyzed epimerization of three pigments, BChl [Formula: see text], Chl [Formula: see text], and 3-acetyl Chl [Formula: see text], to elucidate the structural factors that are responsible for epimerization reactions. We compared the epimerization kinetics of the three pigments and concluded that the bacteriochlorin skeleton (7,8,17,18-tetrahydroporphyrin) significantly retarded the epimerization kinetics. Thus, BChl [Formula: see text] exhibited slower epimerization kinetics than Chl [Formula: see text] in spite of the presence of the electron-withdrawing 3-acetyl group that accelerates epimerization. In contrast to the large structural effects of (B)Chl molecules on epimerization kinetics, the thermodynamic properties at equilibrium in the epimerization of the three pigments were barely influenced by their molecular structures. This study also demonstrates that a semi-synthetic pigment, 3-acetyl Chl [Formula: see text], is appropriate for comparative analyses of the structural effects of BChl [Formula: see text] and Chl [Formula: see text] on their physicochemical properties.

Acoustic-emission inspection of the kinetics of fatigue cracks in turbomachinery disks

1992 ◽  
Vol 25 (6) ◽  
pp. 303
Author(s):  
M.D. Banov ◽  
A.A. Shanyavaskii ◽  
A.I. Urbakh ◽  
D.A. Troenkin ◽  
E.A. Konyaev ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fatigue Cracks ◽  
Kinetics Of

Study of the kinetics of fatigue cracks by the method of differential compliance

1995 ◽  
Vol 31 (12) ◽  
pp. 1018-1025 ◽  
Author(s):  
V. P. Golub ◽  
V. P. Butseroga ◽  
A. D. Pogrebnyak
Keyword(s):  
Fatigue Cracks ◽  
Kinetics Of

Action of water on the kinetics of fatigue cracks in heat-hardened spring steel

1977 ◽  
Vol 12 (2) ◽  
pp. 157-161 ◽  
Author(s):  
O. N. Romaniv ◽  
Ya. N. Gladkii ◽  
A. N. Kuroshchenov
Keyword(s):  
Fatigue Cracks ◽  
Spring Steel ◽  
Kinetics Of
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