scholarly journals Validation of Simple Equations Describing the Adsorption of Binary Gas Mixtures onto Surfaces with an Asymmetric Distribution of Adsorption Energy

2007 ◽  
Vol 25 (8) ◽  
pp. 597-606
Author(s):  
Paweł Szabelski ◽  
Krzysztof Nieszporek ◽  
Mateusz Drach
Keyword(s):  
Phase Diagrams ◽  
Adsorption Energy ◽  
Numerical Solutions ◽  
Gas Adsorption ◽  
Integral Equation Method ◽  
Simulation Method ◽  
The Other ◽  
Asymmetric Distribution ◽  
Adsorption Equilibria ◽  
Simple Equations

The Monte Carlo simulation method was used to test the accuracy of approximate equations derived for binary gas adsorption onto a heterogeneous surface characterized by a Dubinin-Astakhov adsorption energy distribution (AED) function. In particular, the Condensation Approximation (CA) was applied to obtain simple equations for the partial adsorption isotherms and phase diagrams in the system for which a separate AED was assumed for each component of the mixture. A few cases involving different relationships between the AEDs associated with the adsorbing components were discussed. Additionally, the results of the proposed theory were compared with exact numerical solutions obtained using the Integral Equation method. From both simulations and numerical calculations, it follows that, in general, the CA is not appropriate for the prediction of binary adsorption equilibria when the individual AEDs are of an entirely different shape. On the other hand, when the AEDs were microscopically correlated, i.e. when the adsorption energy of one component on every site was shifted by a constant value compared to that of the other, the phase diagrams obtained were found to be in a very good agreement with their simulated counterparts.

scholarly journals Adsorption and Sensing Behaviors of Pd-Doped InN Monolayer upon CO and NO Molecules: A First-Principles Study

2019 ◽  
Vol 9 (16) ◽  
pp. 3390
Author(s):  
Shiyuan Zhu ◽  
Shouxiao Ma
Keyword(s):  
Transition Metal ◽  
Physicochemical Properties ◽  
Band Gap ◽  
Adsorption Energy ◽  
First Principles ◽  
Gas Adsorption ◽  
The Other ◽  
Promising Candidate ◽  
Potential Applications ◽  
Electronic Behavior

A transition metal (TM) doped InN monolayer has demonstrated with superior behavior for gas adsorption and sensing. For this paper, we studied the adsorption behavior of a Pd-doped InN (Pd-InN) monolayer upon CO and NO using the first-principles theory. Our results show that the Pd-InN monolayer has a stronger interaction with the CO molecule, compared with the NO molecule, with larger adsorption energy of 2.12 eV, compared to −1.65 eV. On the other hand, the Pd-InN monolayer undergoes more obvious deformation of the electronic behavior in the NO system, making the surface become semimetallic with a 0 eV band gap. Thus, the Pd-InN monolayer could be a promising candidate as a resistance-type sensor for NO detection and as a gas adsorbent for CO removal. We are hopeful that this work can offer the basic physicochemical properties and potential applications of the Pd-InN monolayer, which is beneficial for its further exploration in many fields.

scholarly journals Application of the Integral Equation Approach to the Study of Enthalpic Effects Accompanying Mixed-Gas Adsorption on Heterogeneous Solid Surfaces

2002 ◽  
Vol 20 (3) ◽  
pp. 243-260 ◽  
Author(s):  
Krzysztof Nieszporek
Keyword(s):  
Integral Equation ◽  
Gas Adsorption ◽  
Pure Component ◽  
Equation Approach ◽  
Mixed Gas ◽  
Adsorption Equilibria ◽  
Energetic Heterogeneity ◽  
Integral Equation Approach ◽  
Adsorption Energy Distribution ◽  
Simple Equations

The possibilities of the Integral Equation approach for describing mixed-gas adsorption equilibria are presented. In this study, the energetic heterogeneity was described through the use of the Gaussian-like adsorption energy distribution function. As a result, very simple equations describing the isosteric heats of mixture components were obtained. The advantage of the model presented is the possibility of predicting the phase diagrams and enthalpic effects accompanying mixed-gas adsorption from a theoretical viewpoint based on pure-component adsorption data. New equations for isosteric heats of component mixtures were examined using the experimental data obtained by Dunne et al. (1996a, b, 1997), i.e. C2H6, CH4 adsorbed on silicalite and CO2, C2H6 adsorbed on NaX zeolite. The calculations are relatively simple and can be applied industrially.

scholarly journals An augmented Lagrangian method for solving total variation (TV)-based image registration model

2020 ◽  
Vol 14 ◽  
pp. 174830262097353
Author(s):  
Noppadol Chumchob ◽  
Ke Chen
Keyword(s):  
Image Registration ◽  
Augmented Lagrangian ◽  
Numerical Solutions ◽  
Augmented Lagrangian Method ◽  
Closed Form Solution ◽  
Numerical Algorithms ◽  
Lagrangian Method ◽  
Form Solution ◽  
The Other ◽  
Other Hand

Variational methods for image registration basically involve a regularizer to ensure that the resulting well-posed problem admits a solution. Different choices of regularizers lead to different deformations. On one hand, the conventional regularizers, such as the elastic, diffusion and curvature regularizers, are able to generate globally smooth deformations and generally useful for many applications. On the other hand, these regularizers become poor in some applications where discontinuities or steep gradients in the deformations are required. As is well-known, the total (TV) variation regularizer is more appropriate to preserve discontinuities of the deformations. However, it is difficult in developing an efficient numerical method to ensure that numerical solutions satisfy this requirement because of the non-differentiability and non-linearity of the TV regularizer. In this work we focus on computational challenges arising in approximately solving TV-based image registration model. Motivated by many efficient numerical algorithms in image restoration, we propose to use augmented Lagrangian method (ALM). At each iteration, the computation of our ALM requires to solve two subproblems. On one hand for the first subproblem, it is impossible to obtain exact solution. On the other hand for the second subproblem, it has a closed-form solution. To this end, we propose an efficient nonlinear multigrid (NMG) method to obtain an approximate solution to the first subproblem. Numerical results on real medical images not only confirm that our proposed ALM is more computationally efficient than some existing methods, but also that the proposed ALM delivers the accurate registration results with the desired property of the constructed deformations in a reasonable number of iterations.

scholarly journals On the concept of habitus: Feminist critic of Pierre Bourdieu’s social theory

2013 ◽  
Vol 24 (2) ◽  
pp. 174-192
Author(s):  
Dejan Petrovic
Keyword(s):  
Action Potential ◽  
Feminist Theory ◽  
Social Theory ◽  
Social Power ◽  
Social Activism ◽  
The Other ◽  
Symbolic Violence ◽  
Critical Examination ◽  
Asymmetric Distribution ◽  
Theoretical System

Key contemporary sociological theorists, such as Foucault or Habermas rarely explicitly discussed gender in their studies. This fact has not caused a lack of interest in the critical examination of the theoretical systems of these authors within a feminist perspective. During the 1990?s feminists? attention was drawn to Pierre Bourdieu?s social theory. French sociologist?s study Masculine Domination deals with issues of gender dynamics and its reproduction. In this study the persistence of the asymmetric distribution of social power between women and men is explained by concepts of habitus and symbolic violence. As this article will show, social change cannot be explained by Bourdieu?s concept of habitus, as a key link between social structure and action, due to its reduction of actors to socialized bodies, which are practically deprived of any true action potential. On the other hand, with regard to social activism as a permanent feature of feminist theory, this paper seeks to examine whether critical examination of Bourdieu?s conceptual apparatus achieves to provide the means to overcome the aforementioned shortcomings of the theoretical system of French sociologist. In other words, this article seeks to answer the question whether such a modification of habitus is possible, which will allow for actors whose action is truly structured and structuring, and lead to possible change of existing power relations.

scholarly journals The Time-Driven Activity-Based Costing Model for a Small Startup in Indonesia

2020 ◽  
Vol 11 (2) ◽  
pp. 141-148
Author(s):  
Dewi Fitriasari ◽  
Naoko Kawahara
Keyword(s):  
Human Capital ◽  
Development Process ◽  
Simulated Data ◽  
Simulation Method ◽  
The Other ◽  
Software Development Process ◽  
Activity Based Costing ◽  
Regulatory Data ◽  
Costing System ◽  
And Performance

The research proposed a Time-Driven Activity-Based Costing (TDABC) model for cost and human capital analysis in a small startup in Indonesia. TDABC discussed and illustrated the integration of capabilities into cost and performance in startups. The researchers applied a qualitative simulation method. The data were taken from actual regulatory data of wage and salary from the local government of Jakarta. The other data were simulated data based on a software development process for a small startup. The result indicates that the TDABC can assist the company to trace its performance and costs. Additional factors in implementing the costing system are provided for further research and practical considerations in adopting the costing system.

Intriguing differences in hydrogen adsorption in CPO-27 materials induced by metal substitution

2015 ◽  
Vol 3 (9) ◽  
pp. 4827-4839 ◽  
Author(s):  
Mali H. Rosnes ◽  
Martin Opitz ◽  
Matthias Frontzek ◽  
Wiebke Lohstroh ◽  
Jan Peter Embs ◽  
...  
Keyword(s):  
Comparative Study ◽  
Gas Adsorption ◽  
Hydrogen Adsorption ◽  
Isosteric Heat ◽  
Heat Of Adsorption ◽  
Hydrogen Gas ◽  
The Other ◽  
Metal Substitution ◽  
Isosteric Heat Of Adsorption ◽  
Open Metal Sites

We present a comparative study of hydrogen gas adsorption experiments on CPO-27–Cu and –Mn. The initial isosteric heat of adsorption in CPO-27–Cu is low for a material containing open metal sites and in contrast to the other members of the CPO-27 series, including the Mn compound.

scholarly journals Current Progress on the Surface Chemical Modification of Carbonaceous Materials

Coatings ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 103 ◽  
Author(s):  
Adeela Rehman ◽  
Mira Park ◽  
Soo-Jin Park
Keyword(s):  
Energy Storage ◽  
Chemical Modification ◽  
Adsorption Energy ◽  
Gas Adsorption ◽  
Activated Carbons ◽  
Research Areas ◽  
Precise Knowledge ◽  
Chemically Modified Surfaces ◽  
Main Emphasis ◽  
Modified Activated Carbons

Carbon-based materials is considered one of the oldest and extensively studied research areas related to gas adsorption, energy storage and wastewater treatment for removing organic and inorganic contaminants. Efficient adsorption on activated carbon relies heavily upon the surface chemistry and textural features of the main framework. The activation techniques and the nature of the precursor have strong impacts on surface functionalities. Consequently, the main emphasis for scientists is to innovate or improve the activation methods in an optimal way by selecting suitable precursors for desired adsorption. Various approaches, including acid treatment, base treatment and impregnation methods, have been used to design activated carbons with chemically modified surfaces. The present review article intends to deliver precise knowledge on efforts devoted by researchers to surface modification of activated carbons. Chemical modification approaches used to design modified activated carbons for gas adsorption, energy storage and water treatment are discussed here.

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