Material characterization of the main steam gate valve made of X20CrMoV 12.1 steel after long term service

Martensitic steel X20CrMo12.1 has been extensively used within the last few decades as a material for tubing systems and pipelines in thermal power plants (TPP). Long term behavior of this steel is very well known and understood and because of that was found to be reliable material for prolonged service at elevated temperatures. It is well known that during operation TPP components are subject to microstructural changes that inevitably reflect decrease in their mechanical properties that lead to the loss of structural integrity and serviceability of component. This paper deals with the comprehensive investigation carried out on the main steam gate valve parent material of welded joint, as a part of main steam pipeline, after 170.000 h of service (545 degrees C and 19MPa). The obtained results showed that the microstructural degradation caused by long term operation had little effects on the hardness and strength of material, while the changes in impact toughness were observed. Comprehensive microstructural analysis included the examination of the microstructure on the surface and trough the wall thickness

Material characterization of the main steam gate valve made of X20CrMoV 12.1 steel after long term service

Martensitic steel X20CrMo12.1 has been extensively used within the last few decades as a material for tubing systems and pipelines in thermal power plants (TPP). Long term behavior of this steel is very well known and understood and because of that was found to be reliable material for prolonged service at elevated temperatures. It is well known that during operation TPP components are subject to microstructural changes that inevitably reflect decrease in their mechanical properties that lead to the loss of structural integrity and serviceability of component. This paper deals with the comprehensive investigation carried out on the main steam gate valve parent material of welded joint, as a part of main steam pipeline, after 170.000 h of service (545 degrees C and 19MPa). The obtained results showed that the microstructural degradation caused by long term operation had little effects on the hardness and strength of material, while the changes in impact toughness were observed. Comprehensive microstructural analysis included the examination of the microstructure on the surface and trough the wall thickness

Plasma and erythrocyte phospholipid fatty acids composition in serbian hemodialyzed patients

Dyslipidemia is one of the possible risk factors for advanced atherosclerosis in patients with chronic renal failure. Abnormal phospholipid metabolism may play an important role in the progression of atherosclerosis in patients with renal failure. The aim of this study was to determine specific characteristics of plasma and erythrocyte phospholipid content and fatty acid composition in 37 patients with chronic renal failure on hemodialysis (HD). The results were compared with the characteristics of healthy subjects. Briefly, plasma triglyceride (p lt 0.001), total cholesterol (p lt 0.05), and total phospholipids (p lt 0.01) levels were significantly higher and HDL-cholesterol level significantly lower (p lt 0.01) in HD patients. Plasma phosphatidylcholine and phosphatidylethanolamine concentration were significantly higher (p lt 0.001) in HD patients. The plasma phospholipid fatty acids composition indicated significantly (p lt 0.01) higher level of oleic (18:1 n-9) and lower levels of eicopentaenoic (20:5 n-3 EPA) and docosahexaenoic (22:6 n-3 DHA) acids (p lt 0.05). However, in HD patients, the relative concentration of plasma phospholipid n-6 polyunsaturated fatty acid (PUFA) was significantly lower (p lt 0.05). The fatty acid composition of erythrocyte phospholipid in HD patients was modified with EPA and DHA levels significantly lowered (p lt 0.05). Our results demonstrate an abnormal phospholipid metabolism and deficiency of n-3 PUFA in plasma and erythrocyte phospholipids in hemodialyzed patients

Relation of CuZnSOD activity with renal insufficiency in hypertensive diabetic patients

Diabetes and renal insufficiency are interrelated metabolic disorders closely associated with redox homeostasis disturbances. The aim of this study was to compare the activity of copper zinc,superoxide dismutase (CuZnSOD) in the erythrocytes of hypertensive diabetic patients with or without renal insufficiency with normal healthy control subjects. In both groups of diabetic patients, blood glucose level and the content of glycosylated hemoglobin (HbA(lc)) were higher than in the control group. However, CuZnSOD activity was significantly higher than control only in hypertensive diabetic patients with renal insufficiency. Our results suggest that disturbances in superoxide homeostasis do correlate with long-term complication in diabetes, i.e. diabetic renal insufficiency and hypertension.Ministry of Education and Science of the Republic of Serbia [173055

Relation of CuZnSOD activity with renal insufficiency in hypertensive diabetic patients

Diabetes and renal insufficiency are interrelated metabolic disorders closely associated with redox homeostasis disturbances. The aim of this study was to compare the activity of copper zinc,superoxide dismutase (CuZnSOD) in the erythrocytes of hypertensive diabetic patients with or without renal insufficiency with normal healthy control subjects. In both groups of diabetic patients, blood glucose level and the content of glycosylated hemoglobin (HbA(lc)) were higher than in the control group. However, CuZnSOD activity was significantly higher than control only in hypertensive diabetic patients with renal insufficiency. Our results suggest that disturbances in superoxide homeostasis do correlate with long-term complication in diabetes, i.e. diabetic renal insufficiency and hypertension.Ministry of Education and Science of the Republic of Serbia [173055