15,140 research outputs found
Facial emotion recognition after subcortical cerebrovascular diseases
published_or_final_versio
A study of drag force in isothermal bubbly flow
Driven by the extensive demands of simulating highly concentrated gas bubbly flows in many engineering fields, numerical studies have been performed to investigate the neighbouring effect of a swarm of bubbles on the interfacial drag forces. In this study, a novel drag coefficient correlation (Simonnet et al., 2007) in terms of local void fraction coupled with the population balance model based on average bubble number density (ABND) has been implemented and compared with Ishii-Zuber densely distributed fluid particles drag model. The predicted local radial distributions of three primitive variables: gas void fraction, Sauter mean bubble diameter, and gas velocity, are validated against the experimental data of Hibiki et al. (2001). In general, satisfactory agreements between predicted and measured results are achieved by both drag force models. With additional consideration for closely packed bubbles, the latest coefficient model by Simonnet et al. (2007) shows considerably better performance in capturing the reduction of drag forces incurred by neighbouring bubbles
Modelling horizontal gas-liquid flow using averaged bubble number density approach
In this study, the internal phase distributions of gas-liquid bubbly flow in a horizontal pipe have been predicted using the population balance model based on Average Bubble Number Density approach. Four flow conditions with average gas volume fraction ranging from 4.4% to 20% have been investigated. Predicted local radial distributions of void fraction, interfacial area concentration and gas velocity have been validated against the experimental data. In general, satisfactory agreements between predicted results and measured values have been achieved. For high superficial gas velocity, it has been ascertained that peak local void fraction of 0.7 with interfacial area concentration of 800 m-1 can be encountered near the top wall of the pipe. Some discrepancies have nonetheless been found between the numerical and experimental results at certain locations of the pipe. The insufficient resolution of the turbulent model in fully accommodating the strong turbulence in the current pipe orientation and the inclusion of additional interfacial force such as the prevalent bouncing force among bubbles remain some of the outstanding challenging issues need to be addressed in order to improve the prediction of horizontal gas-liquid bubbly flow
Examining common information technology addictions and their relationships with non-technology-related addictions
A number of novel problematic behaviors have emerged in the information technology era, and corresponding addictions have been proposed for some of these behaviors. Scholars have speculated that a common factor may underlie these information technology addictions, but this theoretical notion has yet to be tested empirically. The present study tested this notion and also investigated the relationships of information technology addictions with other behavioral addictions as well as substance addictions. We conducted an online survey in 1001 US adults (56% female; mean age = 35.0 years, range = 18–83). Two conceptual models were formulated and tested. Moreover, correlations of the information technology addictions with both problematic gambling and alcohol use disorder were examined. The confirmatory factor analysis showed that there was a common factor underlying various types of information technology addiction. In addition, problematic gambling was more strongly correlated with information technology addiction than alcohol use disorder was. Our findings are interpreted in light of a spectrum approach, which conceptualizes information technology addiction as a cluster of disorders comprising not only shared risk factors and symptoms but also distinct characteristics. The findings further reveal that information technology addiction is more similar to other behavioral addictions than substance-related addictions. Implications for researchers and practitioners are discussed.published_or_final_versio
The association between glycated haemoglobin and waist circumference in the US population
INTRODUCTION: Glycated haemoglobin (A1C) is now used for the diagnosis of diabetes and pre-diabetes. As these are related to obesity, we studied their relationship with waist circumference. METHODS: We analysed data on 960 men and 1001 women who participated in the United States National Health and Nutrition Examination Survey 2007-08. Participants who were older than 20 years, had …published_or_final_versionThe 17th Medical Research Conference, The University of Hong Kong, Hong Kong, 14 January 2012. In Hong Kong Medical Journal, 2012, v. 18 suppl. 1, p. 43, abstract no. 6
Recyclable Magnetite Nanoparticle Catalyst for One-Pot Conversion of Cellobiose to 5-Hydroxymethylfurfural in Water
Environmentally benign and easily recoverable magnetite nanoparticles (Fe3O4 NPs) were demonstrated to catalyze the one-pot conversion of cellobiose, a glucose disaccharide, to 5-hydroxymethylfurfural (5-HMF).Theconversion was achieved in water under hydrothermal conditions.The catalytic activity of Fe3O4 NPs surpassed those of iron (II) and iron (III) chlorides in this reaction. Optimized cellobiose conversion reactions catalyzed with Fe3O4 NPs gave the highest 5-HMF yields of 23.4 ± 0.6% at 160∘C for 24 hours. After three reuses, the Fe3O4 NP catalyst retained its catalytic activity with similar 5-HMF yields, demonstrating the recyclability of this eco-friendly catalyst in water
Recyclable Magnetite Nanoparticle Catalyst for One-Pot Conversion of Cellobiose to 5-Hydroxymethylfurfural in Water
Environmentally benign and easily recoverable magnetite nanoparticles (Fe3O4 NPs) were demonstrated to catalyze the one-pot conversion of cellobiose, a glucose disaccharide, to 5-hydroxymethylfurfural (5-HMF). The conversion was achieved in water under hydrothermal conditions. The catalytic activity of Fe3O4 NPs surpassed those of iron (II) and iron (III) chlorides in this reaction. Optimized cellobiose conversion reactions catalyzed with Fe3O4 NPs gave the highest 5-HMF yields of 23.4 ± 0.6% at 160°C for 24 hours. After three reuses, the Fe3O4 NP catalyst retained its catalytic activity with similar 5-HMF yields, demonstrating the recyclability of this eco-friendly catalyst in water
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