Modified PSVL: A second order model for thermal simulation of Stirling engines based on convective–polytropic heat transfer of working spaces

2015 ◽  
Vol 85 ◽  
pp. 340-355 ◽  
Author(s):  
Mojtaba Babaelahi ◽  
Hoseyn Sayyaadi
Keyword(s):  
Heat Transfer ◽  
Thermal Simulation ◽  
Second Order ◽  
Order Model ◽  
Stirling Engines ◽  
Second Order Model

Isothermal Microtube Heat Transfer With Second-Order Slip Flow and Temperature Jump Boundary Conditions

2006 ◽  
Author(s):  
Nian Xiao ◽  
John Elsnab ◽  
Susan Thomas ◽  
Tim Ameel
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Nusselt Number ◽  
Boundary Conditions ◽  
Temperature Jump ◽  
Slip Flow ◽  
Second Order ◽  
Order Model ◽  
First Order ◽  
Second Order Model

Two analytical models are presented in which the continuum momentum and energy equations, coupled with second-order slip flow and temperature jump boundary conditions, are solved. An isothermal boundary condition is applied to a microchannel with a circular cross section. The flow is assumed to be hydrodynamically fully developed and thermal field is either fully developed or thermally developing from the tube entrance. A traditional first-order slip boundary condition is found to over predict the slip velocity compared to the second-order model. Heat transfer increases at the upper limit of the slip regime for the second-order model. The maximum second-order correction to the first-order Nusselt number is on the order of 18% for air. The second-order effect is also more significant in the entrance region of the tube. The Nusselt number decreases relative to the no-slip value when slip and temperature jump effects are of the same order or when temperature jump effects dominate. When temperature jump effects are small, the Nusselt number increases relative to the no-slip value. Comparisons to a previously reported model for an isoflux boundary condition indicate that the Nusselt number for the isoflux boundary condition exceeds that for the isothermal case at all axial locations.

Adsorption Kinetics of Pb2+ Ions Using Chitosan Nanoparticles

2013 ◽  
Vol 367 ◽  
pp. 45-49
Author(s):  
Ying Hong ◽  
Ze Hui Zhong ◽  
You Shi Liu
Keyword(s):  
Adsorption Kinetics ◽  
Chitosan Nanoparticles ◽  
Second Order ◽  
Isotherm Model ◽  
Order Model ◽  
Adsorption Characteristics ◽  
Pseudo Second Order ◽  
Kinetics Of ◽  
Second Order Model

Chitosan nanoparticles were prepared by crosslinkingusing TPP. SEM showed that chitosan nanoparticles were successfully obtained.The adsorption characteristics of chitosan nanoparticles were evaluated. Theresults demonstrated that chitosan nanoparticles were suitable for adsorbent toremoval Pb2+. The parameters for the adsorption of Pb2+by chitosan nanoparticles were also determined. It was shown that chitosannanoparticles were fit for Langmuir’s isotherm model and that the adsorptionkinetics of Pb2+ described by the pseudo-second-order model could bebest.

Polyaniline/ZnO nanocomposites for the removal of methyl orange dye from waste water

2018 ◽  
Vol 32 (19) ◽  
pp. 1840085 ◽  
Author(s):  
Neha V. Nerkar ◽  
Subhash B. Kondawar ◽  
Snehal Kargirwar Brahme ◽  
Yun Hae Kim
Keyword(s):  
Waste Water ◽  
Methyl Orange ◽  
Adsorption Mechanism ◽  
Second Order ◽  
Pure Pani ◽  
Time Interval ◽  
Order Model ◽  
Vis Spectroscopy ◽  
Pseudo Second Order ◽  
Second Order Model

In this paper, we report the safe removal of methyl orange (MO) dye from aqueous solution using chemical interaction of dye molecule with polyaniline/zinc oxide (PANI/ZnO) nanocomposite. PANI/ZnO nanocomposite has been prepared by in situ polymerization. PANI/ZnO nanocomposite was found to be the best promising candidate for adsorption of dyes due to more porosities compared to that of pure PANI. In the present investigation, PANI/ZnO nanocomposite was mixed in a solution of MO dye and used for adsorption process. Color removal was studied using UV-Vis spectroscopy and the spectra were recorded for specific time interval and validation of kinetic model has been applied. Absorbance of PANI/ZnO nanocomposite was found to be increased as compared to that of pure ZnO nanoparticles and pure PANI due to synergistic effect. Comparatively, the removal of dye was also found to be more by using PANI/ZnO nanocomposites. In order to evaluate kinetic mechanism the pseudo-first-order model, pseudo-second-order model and intraparticle diffusion models were verified by the linear equation analysis. Adsorption mechanism of pseudo-second-order model was systematically explained for removal of dye using PANI/ZnO nanocomposite. The results clearly demonstrated that the adsorption mechanism gives very novel and green method of removal of hazardous dyes from waste water.

scholarly journals Validating a second-order model for oil and gas projects’ investment climate scale

2017 ◽  
Vol 11 (1) ◽  
pp. 65-79 ◽  
Author(s):  
Abdulsalam Mas’ud ◽  
Nor Aziah Abd Manaf ◽  
Natrah Saad
Keyword(s):  
Goodness Of Fit ◽  
Oil And Gas ◽  
Second Order ◽  
Fit Indices ◽  
Investment Climate ◽  
Order Model ◽  
Content Type ◽  
Latent Construct ◽  
Climate Scale ◽  
Second Order Model

Purpose The investment climate is one of the key factors considered by foreign investors while deciding their investment destination. This paper aims to attempt at validating the second-order model of oil and gas projects’ investment climate. Examination of the relationship between the dimensions of oil and gas projects’ investment climate; strategy, participants/operating environment and risk/return; and the overall latent construct was conducted. The study also evaluates the goodness of fit of the second-order model using relevant fit indices. Design/methodology/approach Oil and gas experts in Malaysian marginal oil fields subsector were deployed, through whom responses were collected that formed the data set used in the analysis. Then, the data were used for confirmatory factor analysis, evaluation of the second-order model through path analysis and for model fit evaluation. Findings The finding revealed that the second-order model of oil and gas projects’ investment climate is valid and reliable. It also revealed that all the three dimensions, strategy, participants/operating environment and risk/return, have significant effects on the formation of the oil and gas projects’ investment climate. Finally, the goodness of fit of the second-order model satisfied the relevant fit indices. Research limitations/implications The findings present valuable insights to policymakers on the extent of the influence each of the dimensions has on the overall latent construct. The validity and reliability analysis suggests the measurements of the second-order model of oil and gas projects’ investment climate construct, and its dimensions are valid, reliable and fit for future empirical research. Thus, it calls for replication in other oil and gas settings. Originality/value The findings from the results of this study are pioneering. Extant literature falls short in attempting the validation of the second-order oil and gas projects’ investment climate scale, as well as relating each of the dimensions with the overall latent construct.

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