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The purpose of this study is to investigate the rheological behaviour of commercial lubrication oils used for cylinder lubrication in two-stroke marine diesel engines…
The purpose of this study is to investigate the rheological behaviour of commercial lubrication oils used for cylinder lubrication in two-stroke marine diesel engines. Furthermore, it is of interest to investigate whether the viscosity of lubrication oils is affected by different levels of alkalinity.
Viscosity measurements are performed using both rotational and capillary rheometry. It was possible to measure oil viscosity in the shear rate from 0.1 to 3,000 s−1 using rotational rheometry, whereas capillary rheometry allowed measurements in higher shear rates from 5 × 105 to 1.3 × 106 s−1 at 50°C.
The viscosity measurements show that the studied lubrication oils behave as a Newtonian fluid and that the viscosities are insensitive to the level of alkalinity. Furthermore, the viscosity/temperature dependency for the lubrication oils was found to fit the Arrhenius model.
This study presents useful information about the rheological behaviour of lubrication oils, more precisely how the oil properties are affected by shear rate, temperature and level of alkalinity. The value of this research is considered to be important for designing two-stroke diesel engines and cylinder lubrication systems.
The purpose of this paper is a review of updated evidence of a J-shaped association between alcohol consumption and the risk of coronary heart disease (CHD) and all-cause…
The purpose of this paper is a review of updated evidence of a J-shaped association between alcohol consumption and the risk of coronary heart disease (CHD) and all-cause mortality in relation to public health issues to create a basis for sensible individual health deliberations.
A review of the evidence from the first observation of a J-shaped association between a moderate alcohol intake and CHD in 1926 to recent studies of the effect of healthy lifestyles (including moderate alcohol intake) on life expectancy free of cardiovascular disease (CVD), cancer and Type 2 diabetes. An update on the biological plausibility of the J-shaped association with focus on recent findings of the association of alcohol intake and blood lipid levels.
Plausible J-shaped relations between light to moderate alcohol consumption and the risk of CHD, CVD mortality and all-cause mortality have been found in a large number of robust epidemiological studies. Among the potential mechanisms underlying the proposed protective effects are higher levels of high-density lipoprotein lacking apolipoprotein C3, reduced platelet aggregability, increased level of endothelial cell fibrinolysis, increased insulin sensitivity and decreased inflammation.
The existence of a J-shaped association between alcohol consumption and the risk of CHD and all-cause mortality is based on observational evidence and accordingly challenged by a degree of uncertainty leading some public health circles to state: “there is no safe level of alcohol consumption.” The authors propose that communication on the pros and cons of alcohol intake should emphasize the nadir of a J-shaped curve as a healthy range for the general population while advice regarding the consumption of alcohol should be adjusted to factor in the risks and potential benefits for each individual patient considering age, sex, family history, personal drinking history and specific medical history.