Study on the Emission Characteristics in Renewable Energy Combustion under Different Working Conditions of Marine Two-Stroke Diesel Engine

In this paper, MAN 6S35ME-B9 two-stroke diesel engine is taken as the research object. By constructing a detailed combustion reaction mechanism including CH4, C4H10O, nitrides and other substances, CHEMKIN-PRO is used to simulate the same fuel mixing ratio and excess air coefficient. Under the condition of 1.5, the temperature, NO mole fraction and NH3 mole fraction in the reactor change and study the factors affecting the pollutant emission of marine diesel engine with the crank angle under different working conditions. The simulation shows that with the decrease of diesel engine speed, the maximum temperature of combustion reaction and the temperature at exhaust opening are obviously reduced. At the same time, mole fraction of NO and NH3 decreases with the decrease of rotational speed, and there is no nitride production in the combustion reaction at 25%

Under Different Working Conditions Carbon Oxides and Nitrogen Oxides Emission of n-Butanol and LNG in Diesel Engine

Through the establishment of covering substances such as CH4, C4H10O, nitride specific combustion reaction mechanism, carbon oxides and nitrogen oxides emissions can be simulated by CHEMKIN-PRO at the four fuel mixing ratios and same excess air coefficient, the Man 6S35ME-B9dual-stroke diesel engine was used as the experimental object. Changes in temperature, pressure, mole fraction of NO and mole fraction of CO2 in the reactor were investigated at 1.5, and the influence factors of crank angle on pollutant emission of marine diesel engine under various operating conditions were studied. The simulation results show that with the loss of the diesel engine rotating speed, exhaust temperature and exhaust pressure significantly reduced. In the meantime, the mole-percent of NO and CO2 decreased with the decrease of rotational speed. Compared with the rotational speed of 142 r/min, the molar mass of NO and CO2 in exhaust gas decreased by 54.7% and 24.1% at 89.5 r/min, respectively

Study on the Emission Characteristics in Renewable Energy Combustion under Different Working Conditions of Marine Two-Stroke Diesel Engine

In this paper, MAN 6S35ME-B9 two-stroke diesel engine is taken as the research object. By constructing a detailed combustion reaction mechanism including CH4, C4H10O, nitrides and other substances, CHEMKIN-PRO is used to simulate the same fuel mixing ratio and excess air coefficient. Under the condition of 1.5, the temperature, NO mole fraction and NH3 mole fraction in the reactor change and study the factors affecting the pollutant emission of marine diesel engine with the crank angle under different working conditions. The simulation shows that with the decrease of diesel engine speed, the maximum temperature of combustion reaction and the temperature at exhaust opening are obviously reduced. At the same time, mole fraction of NO and NH3 decreases with the decrease of rotational speed, and there is no nitride production in the combustion reaction at 25%

Body Mass Index Is Better than Other Anthropometric Indices for Identifying Dyslipidemia in Chinese Children with Obesity.

BACKGROUND:Body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHR) are used in screening and predicting obesity in adults. However, the best identifier of metabolic complications in children with obesity remains unclear. This study evaluated lipid profile distribution and investigated the best anthropometric parameter in association with lipid disorders in children with obesity. METHODS:A total of 2243 school children aged 7-17 years were enrolled in Guangzhou, China, in 2014. The anthropometric indices and lipid profiles were measured. Dyslipidemia was defined according to the US Guidelines for Cardiovascular Health and Risk Reduction in Children and Adolescents. The association between anthropometry (BMI, WC, and WHR) and lipid profile values was examined using chi-square analysis and discriminant function analysis. Information about demography, physical activity, and dietary intake was provided by the participant children and their parents. RESULTS:Children aged 10-14 and 15-17 years old generally had higher triglyceride values but lower median concentration of total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol compared with children aged 7-9 years old (all P < 0.001). These lipid parameters fluctuated in children aged 10-14 years old. The combination of age groups, BMI, WC and WHR achieved 65.1% accuracy in determining dyslipidemic disorders. BMI correctly identified 77% of the total dyslipidemic disorders in obese children, which was higher than that by WHR (70.8%) (P< 0.05). CONCLUSION:The distribution of lipid profiles in Chinese children differed between younger and older age groups, and the tendency of these lipid levels remarkably fluctuated during 10 to 14 years old. BMI had better practical utility in identifying dyslipidemia among school-aged children with obesity compared with other anthropometric measures

Results of Discriminant Function Analysis for Classifying Dyslipidemia among Children (<i>n</i> = 2243).

<p>Results of Discriminant Function Analysis for Classifying Dyslipidemia among Children (<i>n</i> = 2243).</p

Distribution of Lipid Profile in Boys and Girls Aged 7–17 Years Old (<i>n</i> = 2243).

<p>Distribution of Lipid Profile in Boys and Girls Aged 7–17 Years Old (<i>n</i> = 2243).</p

Proportion of Lipid Disorders in Children Defined by BMI, WC, and WHR (<i>n</i> = 2243).

<p>Proportion of Lipid Disorders in Children Defined by BMI, WC, and WHR (<i>n</i> = 2243).</p

Median Concentration (IQR) of the Lipid Profile among Children Aged 7–17 Years in This Study (<i>n</i> = 2243).

<p>Median Concentration (IQR) of the Lipid Profile among Children Aged 7–17 Years in This Study (<i>n</i> = 2243).</p

Descriptive Characteristics of Children Ranging from 7 to 17 Years Old in Guangzhou, 2014 (<i>n</i> = 2243).

<p>Descriptive Characteristics of Children Ranging from 7 to 17 Years Old in Guangzhou, 2014 (<i>n</i> = 2243).</p