Oxidation Behavior of Alumina-Forming Austenitic Steels in Superheated Steam at 700 °C

2020 ◽  
Vol 6 (3) ◽  
Author(s):  
Bingjie Xiao ◽  
Nick Tepylo ◽  
Xiao Huang ◽  
Zhangjian Zhou ◽  
Sami Penttilä
Keyword(s):  
Weight Loss ◽  
Weight Gain ◽  
Oxide Layer ◽  
Internal Oxidation ◽  
Oxidation Behavior ◽  
Superheated Steam ◽  
External Surface ◽  
Austenitic Steels ◽  
Surface Oxide Layer ◽  
Oxide Spallation

Abstract In this study, three alumina-forming austenitic (AFA) steels (Fe-18Ni-12Cr-AlNbC, Fe-18Ni-12Cr-Al, and Fe-18Ni-16Cr-AlNbC) were exposed to superheated steam (SHS) at 700 °C for 1000 h to study their oxidation behavior. The Fe-18Ni-16Cr-AlNbC alloy showed the best performance as it had the least weight gain due to a denser surface oxide layer and the lack of internal oxidation. The Fe-18Ni-12Cr-AlNbC alloy suffered from internal oxidation and had a greater weight gain than Fe-18Ni-16Cr-AlNbC, while Fe-18Ni-12Cr-Al experienced weight loss due to perhaps external oxide spallation, leaving a less protective Fe-oxide on the external surface.

Oxidation Behavior of Coating Alloy CoCrMoSi and CoCrMoNiSi in Superheated Steam at 800˚C

2021 ◽  
Author(s):  
Bingjie Xiao ◽  
Xiao Huang ◽  
Matthew Yao
Keyword(s):  
Oxide Layer ◽  
Internal Oxidation ◽  
Power Plants ◽  
Oxidation Behavior ◽  
Superheated Steam ◽  
Surface Oxide ◽  
Laves Phase ◽  
Working Fluid ◽  
Protective Oxide ◽  
Cross Sectional

Abstract As steam power plants continue to move towards higher operating temperatures in order to improve efficiency, materials exposed to the working fluid are subjected to accelerated degradations in the forms of surface oxidation and reduced mechanical properties. In this study, the oxidation behavior of two cobalt base alloys, CoCrMoSi (T14) and CoCrNiMoSi (T19), was evaluated in superheated steam (SHS, 0.1MPa) at 800 °C for up to 500 hours. After the exposure, both T14 and T19 alloys experienced weight gain caused by oxidation. Visual observation and SEM surface analysis revealed that T19 had greater extent of surface oxide spallation than that seen on T14. From the cross-sectional evaluation, however, a thin, adherent oxide layer was found to have formed on T19. T14 in fact had suffered from excessive internal oxidation and the surface oxide was uneven. Based on the results obtained so far, it is believed that the finer Laves phase combined with greater amount of Cr in alloy T19 have enabled the formation of a protective oxide layer and thus reduced the extent of internal oxidation. Due to the extensive oxidation ingress along the large Laves phase, it is concluded that T14 is not suitable for applications in SHS at 800 °C.

scholarly journals Oxidation Behavior of Ceramics for Gas Turbines in Combustion Gas Flow at 1500°C

1997 ◽  
Author(s):  
Y. Etori ◽  
T. Hisamatsu ◽  
I. Yuri ◽  
Y. Yasutomi ◽  
T. Machida ◽  
...  
Keyword(s):  
Weight Loss ◽  
Oxide Layer ◽  
Gas Turbines ◽  
High Speed ◽  
Gas Flow ◽  
Oxidation Behavior ◽  
Loss Rate ◽  
Sintering Aids ◽  
Combustion Gas ◽  
Weight Losses

In order to evaluate the durability of silicon-carbides (SiC) and silicon-nitrides (Si3N4), we studied the oxidation behavior of SiC and Si3N4 in 1500°C combustion gas flow. We found that the exposure to the combustion gas flow resulted in the weight losses of those ceramics due to the partial disappearance of the oxidized surface layer. We investigated the effects of sintering aids and high speed gas flow as possible factors for the disappearance of the oxide layer. Two kinds of SiC, without sintering aids and sintered with B4C, were used as test specimens. After the exposure to combustion gas flow conditions of 1500°C, 150m/s, 0.18MPa, the weight loss rate and thickness of the oxide layer were quite the same for each specimen of SiC. The existence of sintering aids did not have any effect on the disappearance of the oxide layer. To investigate the effect of gas flow, we set each specimen in a tube made of SiC to protect it from the gas flow. The tube had two holes each acting both as inlet and exhaust vents. Consequently, the oxide layer formed thickly. But at the spots on the specimen facing the holes, the oxide layer was thin. Hollows occurred on the specimen of SiC at these spots. It seems that the existence of gas flow is a very important factor in the disappearance of the oxide layer. Alumina (Al2O3) and zirconia (ZrO2) as oxide ceramics were exposed to the combustion gas flow. The weight of these also decreased. There is a possibility that the weight loss of ceramics in combustion gas flow is caused by degradation of oxide layer on their surface from erosion and hot corrosion due to some oxide scales coming from the test equipment.

Weight gain causes weight loss

Nature ◽  
2001 ◽  
Author(s):  
John Whitfield
Keyword(s):  
Weight Loss ◽  
Weight Gain

scholarly journals Managing Obesity in Lockdown: Survey of Health Behaviors and Telemedicine

Nutrients ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 1359
Author(s):  
Noga C Minsky ◽  
Dafna Pachter ◽  
Galia Zacay ◽  
Naama Chishlevitz ◽  
Miriam Ben-Hamo ◽  
...  
Keyword(s):  
Weight Loss ◽  
Body Weight ◽  
Weight Gain ◽  
Health Behaviors ◽  
Online Survey ◽  
Eating Patterns ◽  
Weight Changes ◽  
Exercise Habits ◽  
Prevent Weight Gain ◽  
Vegetables And Fruits

Since the outbreak of COVID-19, billions of people have gone into lockdown, facing pandemic related challenges that engender weight gain, especially in the obese. We report the results of an online survey, conducted during Israel’s first quarantine, of 279 adults treated in hospital-based obesity clinics with counseling, medications, surgery, endoscopic procedures, or any combination of these for weight loss. In this study, we assessed the association between changes in dietary and lifestyle habits and body weight, and the benefits of receiving weight management care remotely through telemedicine during lockdown. Compared to patients not receiving obesity care via telemedicine, patients receiving this care were more likely to lose weight (OR, 2.79; p = 0.042) and also to increase participation in exercise (OR, 2.4; p = 0.022). While 40% of respondents reported consuming more sweet or salty processed snacks and 33% reported less vegetables and fruits, 65% reported more homemade foods. At the same time, 40% of respondents reported a reduction in exercise and 52% reported a decline in mood. Alterations in these eating patterns, as well as in exercise habits and mood, were significantly associated with weight changes. This study highlights that lockdown affects health behaviors associated with weight change, and advocates for the use of telemedicine to provide ongoing obesity care during future quarantines in order to promote weight loss and prevent weight gain.

scholarly journals Depression-related weight change and incident diabetes in a community sample

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Eva Graham ◽  
Tristan Watson ◽  
Sonya S. Deschênes ◽  
Kristian B. Filion ◽  
Mélanie Henderson ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Weight Loss ◽  
Weight Gain ◽  
Weight Change ◽  
Short Form ◽  
Community Sample ◽  
Overweight And Obesity ◽  
Community Dwelling ◽  
Increased Risk

AbstractThis cohort study aimed to compare the incidence of type 2 diabetes in adults with depression-related weight gain, depression-related weight loss, depression with no weight change, and no depression. The study sample included 59,315 community-dwelling adults in Ontario, Canada. Depression-related weight change in the past 12 months was measured using the Composite International Diagnostic Interview—Short Form. Participants were followed for up to 20 years using administrative health data. Cox proportional hazards models compared the incidence of type 2 diabetes in adults with depression-related weight change and in adults with no depression. Adults with depression-related weight gain had an increased risk of type 2 diabetes compared to adults no depression (HR 1.70, 95% CI 1.32–2.20), adults with depression-related weight loss (HR 1.62, 95% CI 1.09–2.42), and adults with depression with no weight change (HR 1.39, 95% CI 1.03–1.86). Adults with depression with no weight change also had an increased risk of type 2 diabetes compared to those with no depression (HR 1.23, 95% CI 1.04–1.45). Associations were stronger among women and persisted after adjusting for attained overweight and obesity. Identifying symptoms of weight change in depression may aid in identifying adults at higher risk of type 2 diabetes and in developing tailored prevention strategies.

scholarly journals Weight Cycling in Women: Adaptation or Risk?

2020 ◽  
Author(s):  
Katelyn J. Carey ◽  
Wendy Vitek
Keyword(s):  
Weight Loss ◽  
Body Composition ◽  
Weight Gain ◽  
Pregnancy Complications ◽  
Weight Regain ◽  
Reproductive Age ◽  
Cardiometabolic Health ◽  
Surrogate Markers ◽  
Weight Cycling ◽  
Gut Peptides

AbstractObesity, dieting, and weight cycling are common among reproductive-age women. Weight cycling refers to intentional weight loss followed by unintentional weight regain. Weight loss is accompanied by changes in gut peptides, adipose hormones, and energy expenditure that promote weight regain to a tightly regulated set point. While weight loss can improve body composition and surrogate markers of cardiometabolic health, it is hypothesized that the weight regain can result in an overshoot effect, resulting in excess weight gain, altered body composition, and negative effects on surrogate markers of cardiometabolic health. Numerous observational studies have examined the association of weight cycling and health outcomes. There appears to be modest association between weight cycling with type 2 diabetes mellitus and dyslipidemia in women, but no association with hypertension, cardiovascular events, and overall cancer risk. Interestingly, mild weight cycling may be associated with a decreased risk of overall and cardiovascular mortality. Little is known about the effects of weight cycling in the preconception period. Although obesity and weight gain are associated with pregnancy complications, preconception weight loss does not appear to mitigate the risk of most pregnancy complications related to obesity. Research on preconception weight cycling may provide insight into this paradox.

Insulin and central regulation of spontaneous fattening and weight loss

1985 ◽  
Vol 249 (2) ◽  
pp. R203-R208
Author(s):  
R. B. Melnyk ◽  
J. M. Martin
Keyword(s):  
Weight Loss ◽  
Body Weight ◽  
Weight Gain ◽  
Energy Balance ◽  
Binding Capacity ◽  
Insulin Receptors ◽  
Insulin Binding ◽  
Strong Positive Correlation ◽  
Central Regulation ◽  
Isolated Pancreatic Islets

Insulin binding to receptors in a partially purified hypothalamic membrane preparation is altered by prolonged starvation. To define further the relationship between hypothalamic insulin binding and energy balance, we studied the Richardson's ground squirrel, a hibernator that exhibits spontaneous 6- to 8-mo body weight cycles when kept in constant conditions. Isolated pancreatic islets from squirrels killed during the weight gain phase had greater glucose-stimulated insulin secretion than those from weight loss phase animals, and adipocytes showed significantly greater glucose incorporation into total lipid in response to insulin. Differences in lipogenesis were not attributable to changes in insulin-binding capacity. Hypothalamic tissue from weight gain phase animals bound more insulin than that from weight loss phase animals. Maximal binding was correlated with pancreatic islet responsiveness and maximal insulin-stimulated lipogenesis. The strong positive correlation between peripheral metabolic events associated with spontaneous alterations in energy balance and the binding kinetics of hypothalamic insulin receptors suggests that insulin may play an important role in the central regulation of body weight.

Effect of surface oxide layer on deuterium permeation behaviors through a type 316 stainless steel

2012 ◽  
Vol 87 (5-6) ◽  
pp. 580-583 ◽  
Author(s):  
Yasuhisa Oya ◽  
Makoto Kobayashi ◽  
Junya Osuo ◽  
Masato Suzuki ◽  
Akiko Hamada ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Oxide Layer ◽  
Surface Oxide ◽  
Surface Oxide Layer ◽  
316 Stainless Steel ◽  
Effect Of Surface
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