The influence of degree of saturation on the coefficient of aqueous diffusion

1998 ◽  
Vol 35 (5) ◽  
pp. 811-827 ◽  
Author(s):  
P C Lim ◽  
S L Barbour ◽  
D G Fredlund
Keyword(s):  
Diffusion Coefficient ◽  
Effective Diffusion ◽  
Theoretical Models ◽  
Chloride Ions ◽  
Model Verification ◽  
Degree Of Saturation ◽  
Best Fit ◽  
Coefficient Of Diffusion ◽  
Water Contents

The role of degree of saturation on the coefficient of diffusion of contaminants in the aqueous phase is presented and theoretical models for predicting the coefficient of diffusion at any degree of saturation are described. Three predictive models were developed based on three different diffusion modes: diffusion in parallel and series arrangements and combination of both. Diffusion tests were conducted on a sand at various water contents ranging from saturation to the residual degree of saturation using potassium and chloride ions as tracers to verify the applicability of the models. Results from the diffusion tests showed a decrease in effective diffusion coefficient of potassium with a decrease in degree of saturation. The functional relationship between the normalized diffusion coefficient for potassium and the degree of saturation is slightly nonlinear. The results for chloride also showed a decreasing trend, although the data were quite scattered and further verification is needed. Model verification based on the results for potassium showed that among the three models proposed, the model which combines the diffusion pathways in parallel and series arrangements provides the best fit to the experimental data.Key words: unsaturated, contaminant transport, aqueous diffusion, degree of saturation.

scholarly journals In Vivo Experimental and Analytical Studies for Bevacizumab Diffusion Coefficient Measurement in the Rabbit Vitreous Humor

2020 ◽  
Author(s):  
Shuqi Zhang ◽  
Anita Penkova ◽  
Mark Humayun ◽  
Juan Carlos Martinez-Camarillo ◽  
Abegail C. Tadle ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Effective Diffusion ◽  
Drug Distribution ◽  
Vitreous Humor ◽  
Contour Method ◽  
Experimental Result ◽  
Coefficient Measurement ◽  
A New Technique ◽  
Best Fit

Abstract In order to measure the effective diffusion coefficient of Bevacizumab (Avastin, Genentech) in the vitreous humor, a new technique is developed based on the 'contour method' and in vivo OCT measurements. After injection of Bevacizumab-fluorescein conjugated compound solution into the rabbit eye, the contours of drug concentration distribution at the subsurface of injection were tracked over time. The 2D contours were extrapolated to 3D contours using reasonable assumptions and a numerically integrated analytical model was developed for the theoretical contours for the irregularly shaped drug distribution in the experimental result. By floating the diffusion coefficient, different theoretical contours were constructed and the least-squares best fit to the experimental contours was performed at each time point to get the best fit solution. The approach generated consistent diffusion coefficient values based on the experiments on four rabbit eyes over a period of 3 hours each, which gave , D=1.2±0.6×(?10?^(-6) ?cm?^2)/s and the corresponding theoretical contours matched well with the experimental contours. The quantitative measurement of concentration using OCT and fluorescein labeling gives a new approach for the "non-contact" in vivo drug distribution measurement within vitreous and other ocular tissues.

scholarly journals EFFECTIVE DIFFUSION COEFFICIENT OF CHLORIDE IONS IN SILICA FUME CONCRETE

2009 ◽  
Vol 63 (1) ◽  
pp. 414-420
Author(s):  
Tsuyoshi SHIMA ◽  
Tatsuhiko SAEKI ◽  
Hironori YOSHIZAWA ◽  
Keiki YAMAMOTO
Keyword(s):  
Diffusion Coefficient ◽  
Silica Fume ◽  
Effective Diffusion Coefficient ◽  
Effective Diffusion ◽  
Chloride Ions

A STUDY ON THE FACTORS AFFECTING ELECTRO-MIGRATION CHARACTERISTIC OF CHLORIDE IONS IN CONCRETE

2016 ◽  
Vol 3 (2) ◽  
Author(s):  
Isao Ujike ◽  
Keiyu Kawaai
Keyword(s):  
Diffusion Coefficient ◽  
Pore Structure ◽  
Effective Diffusion Coefficient ◽  
Effective Diffusion ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Test Method ◽  
Reinforced Concrete Structure ◽  
Migration Test ◽  
Factors Affecting

As one of the methods to evaluate the durability performance of reinforced concrete structure for the deterioration due to chloride attack, there is a migration test method. The effective diffusion coefficient by migration test method fluctuates with changes in the pore structure of concrete. In this study, focused on the changes of the pore structure with elapse of age of concrete, the objective of this study is to assess the influence exerted on electro-migration characteristic caused by the type of aggregates and with the condition of early age curing. It is confirmed that the resistibility to the movement by the migration test method of the chloride ion was increased by using non-ferrous slag fine aggregates. In the test specimen using sandstone of 40-65% of water-cement ratio, it is presumed that the increase in the effective diffusion coefficient of chloride ion is caused by the fact that the volume of continuous pore or pore size by the curing method and age of concrete become bigger.

scholarly journals Drying kinetics of sunflower grains

2017 ◽  
Vol 21 (3) ◽  
pp. 203-208 ◽  
Author(s):  
Thaís A. de S. Smaniotto ◽  
Osvaldo Resende ◽  
Kelly A. de Sousa ◽  
Daniel E. C. de Oliveira ◽  
Rafael C. Campos
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficient ◽  
Moisture Content ◽  
Effective Diffusion Coefficient ◽  
Effective Diffusion ◽  
Initial Moisture Content ◽  
Air Ventilation ◽  
Forced Air ◽  
Kinetics Of ◽  
Best Fit

ABSTRACT The objectives of this study were to fit different mathematical models to experimental data of drying of sunflower grains, determine and evaluate the effective diffusion coefficient and obtain the activation energy for the process during the drying under various conditions of air. The sunflower grains were collected with an initial moisture content of 0.5267 dry basis (d.b.) and dried in an oven with forced air ventilation under five temperature conditions: 35, 50, 65, 80 and 95 °C, until reaching the moisture content of 0.0934 ± 0.0061 (d.b.). Among the analyzed models, Wang and Singh showed the best fit to describe the drying phenomenon. The effective diffusion coefficient of sunflower grains increased with the increment in air temperature and has activation energy for liquid diffusion in the sunflower drying of 29.55 kJ mol-1.

M-T Scheme for Predicting Effective Diffusion Coefficient of Chloride Ions in Cement-based Materials

2020 ◽  
Vol 35 (3) ◽  
pp. 520-527
Author(s):  
Guowen Sun ◽  
Jianjian Zhang ◽  
Lijuan Zhang ◽  
Tongning Cao ◽  
Penshuo Wang ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Effective Diffusion Coefficient ◽  
Effective Diffusion ◽  
Chloride Ions ◽  
Cement Based Materials

The Role of Distress Disclosure Tendencies in the Experience and Expression of Laboratory-Induced Sadness

2017 ◽  
Vol 38 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Jeffrey H. Kahn ◽  
Daniel W. Cox ◽  
A. Myfanwy Bakker ◽  
Julia I. O’Loughlin ◽  
Agnieszka M. Kotlarczyk
Keyword(s):  
Individual Differences ◽  
Emotional Reactivity ◽  
Subjective Experience ◽  
Negative Emotion ◽  
Theoretical Models ◽  
Laboratory Research ◽  
Emotion Words ◽  
Distress Disclosure ◽  
Computerized Text Analysis

Abstract. The benefits of talking with others about unpleasant emotions have been thoroughly investigated, but individual differences in distress disclosure tendencies have not been adequately integrated within theoretical models of emotion. The purpose of this laboratory research was to determine whether distress disclosure tendencies stem from differences in emotional reactivity or differences in emotion regulation. After completing measures of distress disclosure tendencies, social desirability, and positive and negative affect, 84 participants (74% women) were video recorded while viewing a sadness-inducing film clip. Participants completed post-film measures of affect and were then interviewed about their reactions to the film; these interviews were audio recorded for later coding and computerized text analysis. Distress disclosure tendencies were not predictive of the subjective experience of emotion, but they were positively related to facial expressions of sadness and happiness. Distress disclosure tendencies also predicted judges’ ratings of the verbal disclosure of emotion during the interview, but self-reported disclosure and use of positive and negative emotion words were not associated with distress disclosure tendencies. The authors present implications of this research for integrating individual differences in distress disclosure with models of emotion.

Exploring the role of identity fusion and group identification in predicting parochialism amongst Indonesian Islamic groups

2019 ◽  
Author(s):  
Christopher Michael Kavanagh ◽  
Susilo Wibisono ◽  
Rohan Kapitány ◽  
Whinda Yustisia ◽  
Idhamsyah Eka Putra ◽  
...  
Keyword(s):  
Group Identification ◽  
Control Sample ◽  
Theoretical Models ◽  
Religious Groups ◽  
Diverse Range ◽  
Beliefs And Practices ◽  
Identity Fusion ◽  
Beliefs And Practice ◽  
Fusion Theory

Indonesia is the most populous Islamic country and as such is host to a diverse range of Islamic beliefs and practices. Here we examine how the diversity of beliefs and practices among Indonesian Muslims relates to group bonding and parochialism. In particular, we examine the predictive power of two distinct types of group alignment, group identification and identity fusion, among individuals from three Sunni politico-religious groups - a fundamentalist group (PKS), a moderate group (NU), and a control sample of politically unaffiliated citizens. Fundamentalists were more fused to targets than moderates or citizens, but contrary to fusion theory, we found across all groups, that group identification (not fusion) better predicted parochialism, including willingness to carry out extreme pro-group actions. We discuss how religious beliefs and practice impact parochial attitudes, as well as the implications for theoretical models linking fusion to extreme behaviour.

scholarly journals Role of Autochthonous Filamentous Fungi in Bioremediation of a Soil Historically Contaminated with Aromatic Hydrocarbons

2006 ◽  
Vol 72 (1) ◽  
pp. 28-36 ◽  
Author(s):  
A. D'Annibale ◽  
F. Rosetto ◽  
V. Leonardi ◽  
F. Federici ◽  
M. Petruccioli
Keyword(s):  
Aromatic Hydrocarbons ◽  
Contaminated Soil ◽  
Chloride Ions ◽  
Lepidium Sativum ◽  
Fungal Colonization ◽  
Soil Toxicity ◽  
Germination Test ◽  
Lignin Peroxidases ◽  
Ph Conditions

ABSTRACT Nine fungal strains isolated from an aged and heavily contaminated soil were identified and screened to assess their degradative potential. Among them, Allescheriella sp. strain DABAC 1, Stachybotrys sp. strain DABAC 3, and Phlebia sp. strain DABAC 9 were selected for remediation trials on the basis of Poly R-478 decolorization associated with lignin-modifying enzyme (LME) production. These autochthonous fungi were tested for the abilities to grow under nonsterile conditions and to degrade various aromatic hydrocarbons in the same contaminated soil. After 30 days, fungal colonization was clearly visible and was confirmed by ergosterol determination. In spite of subalkaline pH conditions and the presence of heavy metals, the autochthonous fungi produced laccase and Mn and lignin peroxidases. No LME activities were detected in control microcosms. All of the isolates led to a marked removal of naphthalene, dichloroaniline isomers, o-hydroxybiphenyl, and 1,1′-binaphthalene. Stachybotrys sp. strain DABAC 3 was the most effective isolate due to its ability to partially deplete the predominant contaminants 9,10-anthracenedione and 7H-benz[DE]anthracen-7-one. A release of chloride ions was observed in soil treated with either Allescheriella sp. strain DABAC 1 or Stachybotrys sp. strain DABAC 3, suggesting the occurrence of oxidative dehalogenation. The autochthonous fungi led to a significant decrease in soil toxicity, as assessed by both the Lepidium sativum L. germination test and the Collembola mortality test.

Diffusion of Heavy Oil in SiO2 Model Catalyst and FCC Catalyst

2012 ◽  
Vol 550-553 ◽  
pp. 158-163 ◽  
Author(s):  
Zi Yuan Liu ◽  
Sheng Li Chen ◽  
Peng Dong ◽  
Xiu Jun Ge
Keyword(s):  
Diffusion Coefficient ◽  
Pore Size ◽  
Effective Diffusion Coefficient ◽  
Pore Diameter ◽  
Effective Diffusion ◽  
Model Catalyst ◽  
Average Pore ◽  
Diffusion Factor ◽  
Fcc Catalyst ◽  
Fcc Catalysts

Through the measured effective diffusion coefficients of Dagang vacuum residue supercritical fluid extraction and fractionation (SFEF) fractions in FCC catalysts and SiO2model catalysts, the relation between pore size of catalyst and effective diffusion coefficient was researched and the restricted diffusion factor was calculated. The restricted diffusion factor in FCC catalysts is less than 1 and it is 1~2 times larger in catalyst with polystyrene (PS) template than in conventional FCC catalyst without template, indicating that the diffusion of SFEF fractions in the two FCC catalysts is restricted by the pore. When the average molecular diameter is less than 1.8 nm, the diffusion of SFEF fractions in SiO2model catalyst which average pore diameter larger than 5.6 nm is unrestricted. The diffusion is restricted in the catalyst pores of less than 8 nm for SFEF fractions which diameter more than 1.8 nm. The tortuosity factor of SiO2model catalyst is obtained to be 2.87, within the range of empirical value. The effective diffusion coefficient of the SFEF fractions in SiO2model catalyst is two orders of magnitude larger than that in FCC catalyst with the same average pore diameter. This indicate that besides the ratio of molecular diameter to the pore diameter λ, the effective diffusion coefficient is also closely related to the pore structure of catalyst. Because SiO2model catalyst has uniform pore size, the diffusion coefficient can be precisely correlated with pore size of catalyst, so it is a good model material for catalyst internal diffusion investigation.

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