Viscosity and rheological properties of ethylene glycol+water+Fe3O4 nanofluids at various temperatures: Experimental and thermodynamics modeling

Mehrdad Mozaffarian,Saeid Atashrouz,Gholamreza Pazuki 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.9

The viscosity and rheological behavior of an ethylene glycol-water mixture based Fe3O4 nanofluid have been experimentally investigated. The nanofluids for this study were prepared by a two-step method in which Fe3O4 nanoparticles were added to a base fluid mixture consisting of 60% (w/w) ethylene glycol and 40% (w/w) water. The measurements were conducted at temperatures ranging from 288.15 to 343.15 K, and at nanoparticle volume fractions ranging from 0.0022 to 0.0055. Furthermore, the dependency of viscosity of nanofluids on shear rate was examined. The results indicate that increasing the shear rate leads to a reduction in the viscosity (shear thinning behavior). Finally, the obtained experimental data was correlated by both a thermodynamic model and a hybrid GMDH-type polynomial neural network, where the mean absolute relative deviation (MARD) of these models was calculated as 3.64% and 3.88%, respectively.

Carbonization and CO2 activation of scrap tires: Optimization of specific surface area by the Taguchi method

Zakaria Loloie,Mehrdad Mozaffarian,Mansooreh Soleimani,Neda Asassian 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.2

This research demonstrates the production of activated carbon from scrap tires via physical activation with carbon dioxide. A newly constructed apparatus was utilized for uninterrupted carbonization and activation processes. Taguchi experimental design (L16) was applied to conduct the experiments at different levels by altering six operating parameters. Carbonization temperature (550-700 oC), activation temperature (800-950 oC), process duration (30-120 min), CO2 flow rate (400 and 600 cc/min) and heating rate (5 and 10 oC/min) were the variables examined in this study. The effect of parameters on the specific surface area (SSA) of activated carbon was studied, and the influential parameters were identified employing analysis of variance (ANOVA). The optimum conditions for maximum SSA were: carbonization temperature=650 oC, carbonization time=60min, heating rate=5 oC/min, activation temperature= 900 oC, activation time=60min and CO2 flow rate=400 cc/min. The most effective parameter was activation temperature with an estimated impact of 49%. The activated carbon produced under optimum conditions was characterized by pore and surface structure analysis, iodine adsorption test, ash content, scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The process yield for optimized activated carbon was 13.2% with the following properties: specific surface area=437m2/g, total pore volume=0.353 cc/g, iodine number=404.7mg/g and ash content=13.9% along with an amorphous structure and a lot of oxygen functional groups. These properties are comparable to those of commercial activated carbons.

Burdens of Cardiometabolic Diseases Attributable to Dietary and Metabolic Risks in Korean Adults 2012–2013

조윤수,신민정,Frederick Cudhea,박주현,Dariush Mozaffarian,Gitanjali Singh 연세대학교의과대학 2017 Yonsei medical journal Vol.58 No.3

Purpose: In line with epidemiological and sociocultural changes in Korea over the past decades, reliable estimation of diseases as a result of dietary and metabolic risks is required. In this study, we aimed to evaluate the contributions of dietary and metabolic factors to cardiometabolic diseases (CMDs) in Korean adults (25–64 years old) during 2012–2013. Materials and Methods: Distribution of risk factors and cause-specific mortality by gender and age per year was obtained from the Korea National Health and Nutrition Examination Survey and Statistics Korea, respectively. The association between the two was obtained from published meta-analyses. The population-attributable fraction attributable to the risk factors was calculated across gender and age strata (male and female, age groups 25–34, 35–44, 45–54, and 55–64) in 2012 and 2013. Results: The results showed that during the period studied, high body mass index [5628 deaths; uncertainty intervals (UIs): 5473–5781] and blood pressure (4202 deaths; UIs: 3992–4410) were major metabolic risks for CMD deaths, followed by dietary risks such as low intake of whole grain (4107 deaths; UIs: 3275–4870) and fruits (3886 deaths; UIs: 3227–4508), as well as high intake of sodium (2911 deaths, UIs: 2406–3425). Also, males and the younger population were seen more prone to be exposed to harmful dietary risk than their female and older counterparts. Conclusion: The findings provide the necessary information to develop targeted government interventions to improve cardiometabolichealth at the population level.

Demographic and lifestyle factors and selenium levels in men and women in the U.S.

Kyong Park,Eric Rimm,David Siscovick,Donna Spiegelman,J. Steven Morris,Dariush Mozaffarian 한국영양학회 2011 Nutrition Research and Practice Vol.5 No.4

Selenium is an antioxidant trace element linked to cardiovascular disease and cancer. Although diet is a major source, relatively little else is known about independent determinants of selenium levels in free-living humans. In this study, we aimed to investigate the independent demographic, lifestyle, and dietary determinants of selenium levels in 1,997 men and 1,905 women in two large prospective U.S. cohorts. Toenail selenium levels were quantified using neutron activation analysis. Diet, geographic residence, demographic, and environmental factors were assessed by validated self-administered questionnaires. Multivariate generalized linear models were conducted to assess the independent relations of these factors with toenail selenium levels, correcting for measurement error in the diet. In multivariable-adjusted analyses, independent predictors of higher selenium were male gender (6.3% higher levels); living in West and Northern-Midwest U.S. regions (8.9% and 7.4% higher than Southern-Midwest regions, respectively); consumption of beef and bread products (between 0.7 - 2.5% higher per daily serving); and selenium supplement use (6.9% higher than non-users); whereas cigarette smoking (5-10% lower than never smokers) , older age (0.6% lower per 5 years), and consumption of eggs, white rice, dairy products, coffee, and alcohol (between 0.1 to 2.0% lower per daily serving) were associated with lower selenium. Multiple dietary and non-dietary factors independently predicted selenium levels, suggesting that both consumption and non-dietary processes (e.g., related to oxidant status) may affect levels. Significant geographic variation in selenium levels exists in the US.

Demographic and lifestyle factors and selenium levels in men and women in the U.S.

Park, Kyong,Rimm, Eric,Siscovick, David,Spiegelman, Donna,Morris, J. Steven,Mozaffarian, Dariush The Korean Nutrition Society 2011 Nutrition Research and Practice Vol. No.

Selenium is an antioxidant trace element linked to cardiovascular disease and cancer. Although diet is a major source, relatively little else is known about independent determinants of selenium levels in free-living humans. In this study, we aimed to investigate the independent demographic. lifestyle, and dietary determinants of selenium levels in 1,997 men and 1,905 women in two large prospective U.S. cohorts. Toenail selenium levels were quantified using neutron activation analysis. Diet, geographic residence, demographic, and environmental factors were assessed by validated self-administered questionnaires. Multivariate generalized linear models were conducted to assess the independent relations of these factors with toenail selenium levels, correcting for measurement error in the diet. In multi variable-adjusted analyses, independent predictors of higher selenium were male gender (6.3% higher levels); living in West and Northern-Midwest U.S. regions (8.9% and 7.4% higher than Southern-Midwest regions, respectively); consumption of beef and bread products (between 0.7 - 2.5% higher per daily serving); and selenium supplement use (6.9% higher than non-users); whereas cigarette smoking (5-10% lower than never smokers), older age (0.6% lower per 5 years), and consumption of eggs, white rice, dairy products, coffee, and alcohol (between 0.1 to 2.0% lower per daily serving) were associated with lower selenium. Multiple dietary and non-dietary factors independently predicted selenium levels, suggesting that both consumption and non-dietary processes (e.g.. related to oxidant status) may affect levels. Significant geographic variation in selenium levels exists in the US.