Effect of preliminary prolonged loading on the properties of steel 18Kh2N4VA AT ?196�C

1968 ◽  
Vol 10 (10) ◽  
pp. 778-779
Author(s):  
G. A. Stepanov
Keyword(s):  
Prolonged Loading ◽  
Steel 18Kh2n4va

Internal oxidation of steel 18Kh2N4VA

1973 ◽  
Vol 15 (7) ◽  
pp. 622-624 ◽  
Author(s):  
I. Ya. Arkhipov
Keyword(s):  
Internal Oxidation ◽  
Steel 18Kh2n4va

Surface hardening of steel 18Kh2N4VA with different stress concentrators

1969 ◽  
Vol 11 (5) ◽  
pp. 354-356
Author(s):  
M. A. Balter ◽  
M. L. Turovskii ◽  
R. A. Novik
Keyword(s):  
Surface Hardening ◽  
Stress Concentrators ◽  
Steel 18Kh2n4va

The effects of deformation, ischemia, and reperfusion on the development of muscle damage during prolonged loading

2011 ◽  
Vol 111 (4) ◽  
pp. 1168-1177 ◽  
Author(s):  
S. Loerakker ◽  
E. Manders ◽  
G. J. Strijkers ◽  
K. Nicolay ◽  
F. P. T. Baaijens ◽  
...  
Keyword(s):  
Muscle Damage ◽  
Tissue Injury ◽  
Severe Form ◽  
Anatomical Location ◽  
Pathological State ◽  
Ischemia And Reperfusion ◽  
Damage Development ◽  
Deep Tissue Injury ◽  
Intrinsic Factors ◽  
Prolonged Loading

Deep tissue injury (DTI) is a severe form of pressure ulcer where tissue damage starts in deep tissues underneath intact skin. In the present study, the contributions of deformation, ischemia, and reperfusion to skeletal muscle damage development were examined in a rat model during a 6-h period. Magnetic resonance imaging (MRI) was used to study perfusion (contrast-enhanced MRI) and tissue integrity (T2-weighted MRI). The levels of tissue deformation were estimated using finite element models. Complete ischemia caused a gradual homogeneous increase in T2 (∼20% during the 6-h period). The effect of reperfusion on T2 was highly variable, depending on the anatomical location. In experiments involving deformation, inevitably associated with partial ischemia, a variable T2 increase (17–66% during the 6-h period) was observed reflecting the significant variation in deformation (with two-dimensional strain energies of 0.60–1.51 J/mm) and ischemia (50.8–99.8% of the leg) between experiments. These results imply that deformation, ischemia, and reperfusion all contribute to the damage process during prolonged loading, although their importance varies with time. The critical deformation threshold and period of ischemia that cause muscle damage will certainly vary between individuals. These variations are related to intrinsic factors, such as pathological state, which partly explain the individual susceptibility to the development of DTI and highlight the need for regular assessments of individual subjects.

Effects of intervals between jumps or bouts on osteogenic response to loading

2002 ◽  
Vol 93 (4) ◽  
pp. 1345-1348 ◽  
Author(s):  
Yoshihisa Umemura ◽  
Naota Sogo ◽  
Akiko Honda
Keyword(s):  
Body Weight ◽  
Control Group ◽  
Prolonged Loading ◽  
Osteogenic Response ◽  
Single Bout

Prolonged loading repetitions can diminish the mechanosensitivity of bones, and increased intervals between loading might restore sensitivity. This study was designed to investigate the effects of intervals between loadings or bouts on osteogenic response. Forty female Fisher 344 rats aged 5 wk were divided into a control group and three exercise groups: 20 jumps in a single bout with a 3-s (S3) or 30-s (S30) jump interval, or 20 jumps in 2 bouts (10 × 2) separated by a 6-h interval with a 3-s jump interval (D3). After 8 wk of training, the bone masses per body weight of the femur and tibia were significantly greater in the three exercise groups than in the control group, and these values were also greater in S30 than in S3, although they were at the same level in D3 and S3. These data suggest that a longer interval (30 s) between individual loading had more effective anabolic effects on bone than a shorter interval (3 s).

Effect of impurities on intercrystalline fracture of steel 18Kh2N4VA after quenching and tempering

1980 ◽  
Vol 12 (2) ◽  
pp. 241-245
Author(s):  
G. A. Filippov ◽  
V. N. Marchenko ◽  
D. A. Litvinenko ◽  
V. I. Sarrak ◽  
O. N. Chevskaya
Keyword(s):  
Intercrystalline Fracture ◽  
Steel 18Kh2n4va ◽  
Effect Of Impurities ◽  
Quenching And Tempering
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