scholarly journals Study on the preventive Measures of Oxide Skin of 12Cr1MoV alloy steel Superheater

Author(s):  
Fengyuan He ◽  
Fei Wang ◽  
Ruqing Niu ◽  
Yao Li
Author(s):  
M.T. Jahn ◽  
J.C. Yang ◽  
C.M. Wan

4340 Ni-Cr-Mo alloy steel is widely used due to its good combination of strength and toughness. The mechanical property of 4340 steel can be improved by various thermal treatments. The influence of thermomechanical treatment (TMT) has been studied in a low carbon Ni-Cr-Mo steel having chemical composition closed to 4340 steel. TMT of 4340 steel is rarely examined up to now. In this study we obtain good improvement on the mechanical property of 4340 steel by TMT. The mechanism is explained in terms of TEM microstructures4340 (0.39C-1.81Ni-0.93Cr-0.26Mo) steel was austenitized at 950°C for 30 minutes. The TMTed specimen (T) was obtained by forging the specimen continuously as the temperature of the specimen was decreasing from 950°C to 600°C followed by oil quenching to room temperature. The thickness reduction ratio by forging is 40%. The conventional specimen (C) was obtained by quenching the specimen directly into room temperature oil after austenitized at 950°C for 30 minutes. All quenched specimens (T and C) were then tempered at 450, 500, 550, 600 or 650°C for four hours respectively.


2015 ◽  
Vol 21 ◽  
pp. 97
Author(s):  
Nitika Malhotra ◽  
Reem Alnazawi ◽  
Ved Gossain ◽  
Matthew Hebdon
Keyword(s):  

Crisis ◽  
2009 ◽  
Vol 30 (4) ◽  
pp. 180-185 ◽  
Author(s):  
Evertjan Jansen ◽  
Marcel C.A. Buster ◽  
Annemarie L. Zuur ◽  
Cees Das

Background: According to recent figures, Amsterdam is the municipality with the highest absolute number of suicides and the second highest suicide rate in the Netherlands. Aims: The aim of the study was to identify time trends and demographic differences in the occurrence of nonfatal suicide attempts versus suicides. Methods: We used registrations of forensic physicians and ambulance services of the Municipal Health Service of Amsterdam to study 1,004 suicides and 6,166 nonfatal attempts occurring in Amsterdam over the period 1996–2005. Results: The number of nonfatal attempts declined from 1996 to 2005, but the number of completed suicides remained relatively stable. Although case fatality was strongly associated with method used, we also found higher case fatalities for men and older people independent of method. Conclusions: The case fatality results suggest differences in motive among different demographic groups: possibly the wish to die is stronger among men and elderly. This finding had implications for the success to be expected from different preventive measures.


2020 ◽  
pp. 7-10
Author(s):  
Vasiliy P. Petropavlovsky ◽  
◽  
Vyacheslav V. Marchenko ◽  
Lyudmila S. Vikulova ◽  
Olga D. Chepeleva ◽  
...  

Summary. Data on distribution of hypodermatosis among large horned cattle in Stavropol region are presented in the article. It was proved that this pathology is widespread in this region. From 12% to 38% of animals from the total number of examined livestock are affected. Ordinary subcutaneous botfly (stroma) Hypoderma bovis de Geer and south subcutaneous botfly (pischevodnik) Hypoderma lineatum de Villers parasites on large horned cattle. The species ratio of gadflies is: Hypoderma bovis (de Gee - 61.1%, Hypoderma lineatum de Villers - 38.9%). The disease is widespread in all climatic zones of Stavropol region. Animals of all age and sex groups are infected, but young animals are more often affected. Linear relationship between the indicators of the transformation of climatic conditions in Stavropol region, the spread of hypodermatosis and the timing of treatment and preventive measures were determined. Authors proved that the complete death of H. bovis and H. lineatum imago (regardless of the time of their hatching) was noted when the temperature drops to -3°C for two days. Thus, this temperature determines the start of treatment and preventive measures against hypodermatosis in the area of animal welfare. When analyzing the histomorphological changes caused by H. bovis and H. lineatum in the body of large horned cattle, perforation of the skin, swelling of adjacent tissues, disorganization of the stroma and structural elements, erythrocyte aggregation, hemorrhages, hydropic degeneration of cellular elements, tissue necrosis, polymorphonuclear leukocyte infiltration of affected organs and tissues were observed. The data on pathogenesis were presented, the analysis of economic damage and the veterinary and sanitary assessment of the products of slaughter of cattle with hypodermatosis were carried out.


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