scholarly journals The Electrical Measurement of Chloride Fluxes in Nitella

1966 ◽  
Vol 19 (3) ◽  
pp. 385 ◽  
Author(s):  
DS Mailman ◽  
I JMullins
Keyword(s):  
Thin Film ◽  
Action Potential ◽  
Effective Diffusion ◽  
Diffusion Constant ◽  
Chloride Ion ◽  
Electrical Measurement ◽  
Chloride Diffusion ◽  
Diffusion Resistance ◽  
Free Solution ◽  
Cell Changes

The chloride efflux from cells of Nitella olavata at rest and during an action potential was continuously monitored by a Ag/AgGl electrode which measured the concentration of chloride in a thin film of solution flowing over the surface of the cell. Changes in the concentration of chloride subsequent to the passage of an action potential were followed and permitted calculation of the change in the flux of chloride ion across the cell membrane. The cell wall offers appreciable diffusion resistance to chloride ion, the effective diffusion constant being less than 1 % of chloride diffusion in free solution. Resting fluxes of chloride were measured in these cells and averaged 3 pmole/cm2 sec. The extra efflux of chloride during an action potential averaged 114 pmole/cm2 impulse.

scholarly journals Mechanical and durability assessment of cement-based and alkali-activated coating mortars in an aggressive marine environment

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Salar Lashkari ◽  
Farzad Yazdipanah ◽  
Mahyar Shahri ◽  
Prabir Sarker
Keyword(s):  
Silica Fume ◽  
Marine Environment ◽  
Strength Test ◽  
High Rate ◽  
Chloride Diffusion ◽  
Strength Development ◽  
Diffusion Resistance ◽  
Capillary Absorption ◽  
Durability Analysis ◽  
Alkali Activated

AbstractCoatings are used as practical solutions against the intrusion of corrosive ions into concrete structures, particularly, in the harsh marine environment. In the present study, the effectiveness of using cement-based and geopolymer-based coatings produced using by-product materials has been evaluated. Silica fume and GGBFS at their optimum dosages were incorporated into mortar mixtures as a cement replacement, and mixtures of NaOH or KOH and sodium silicate solutions were used in the alkali-activated mortars. Shrinkage test, RCMT, and capillary absorption test as common experiments for durability analysis, as well as tests related to the mechanical and bonding properties including compressive strength test, pull-off test, and shear bonding strength test were carried out on the specimens. According to the results, both geopolymer and cement-based mortars improved the compressive and bonding strengths, and chloride diffusion resistance of coatings compared to the OPC mortar. Silica fume was found to be more effective in the strength development of mortars at young ages, while GGBFS was more responsible for acting as a filler and producing further gel in the older ages. The major drawback with geopolymer mortars is the high rate of water absorption and shrinkage coefficient in the early hours, which shows the importance of curing of these mortars at young ages. Overall, the mix design produced with 30% GGBFS and 7.5% silica fume showed the highest durability and mechanical properties and proved to be more compatible with the harsh environment of the Persian Gulf.

High-sensitivity hybrid PbSe/ITZO thin film-based phototransistor detecting from 2100 nm to 2500 nm near-infrared illumination

2022 ◽  
Author(s):  
Ali Sehpar Shikoh ◽  
Gi Sang Choi ◽  
Sungmin Hong ◽  
Kwang Seob Jeong ◽  
Jaekyun Kim
Keyword(s):  
Thin Film ◽  
Metal Oxide ◽  
High Performance ◽  
Near Infrared ◽  
Effective Diffusion ◽  
Band Alignment ◽  
Oxide Thin Film ◽  
Photogenerated Carrier ◽  
Channel Layer ◽  
Metal Oxide Thin Film

Abstract We report that high absorption PbSe colloidal quantum dots (QDs) having a peak absorbance beyond 2100 nm were synthesized and incorporated into InSnZnO (ITZO) channel layer-based thin film transistors (TFTs). It was intended that PbSe QDs with proportionally less photocurrent modulation can be remedied by semiconducting and low off-current ITZO-based TFT configuration. Multiple deposition scheme of PbSe QDs on ITZO metal oxide thin film gave rise to nearly linear increase of film thickness with acceptably uniform and smooth surface (less than 10 nm). Hybrid PbSe/ITZO thin film-based phototransistor exhibited the best performance of near infrared (NIR) detection in terms of response time, sensitivity and detectivity as high as 0.38 s, 3.91 and 4.55 × 107 Jones at room temperature, respectively. This is indebted mainly from the effective diffusion of photogenerated carrier from the PbSe surface to ITZO channel layer as well as from the conduction band alignment between them. Therefore, we believe that our hybrid PbSe/ITZO material platform can be widely used to be in favour of incorporation of solution-processed colloidal light absorbing material into the high-performance metal oxide thin film transistor configuration.

scholarly journals Experimental and Simulation Study on Diffusion Behavior of Chloride Ion in Cracking Concrete and Reinforcement Corrosion

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Yongchun Cheng ◽  
Yuwei Zhang ◽  
Chunli Wu ◽  
Yubo Jiao
Keyword(s):  
Finite Element ◽  
Prediction Models ◽  
Chloride Concentration ◽  
Chloride Ion ◽  
Corrosion Current ◽  
Chloride Diffusion ◽  
Finite Element Models ◽  
Rc Structures ◽  
Cracked Concrete ◽  
Chloride Migration

A chloride ion is a key factor affecting durability of reinforced concrete (RC) structures. In order to investigate chloride migration in cracked concrete, considering the mesoscopic heterogeneity of concrete, concrete modeled here is treated as a four-phase composite consisting aggregate, mortar, crack, and interfacial transition zone (ITZ). In this paper, two-dimensional finite element models of cracked concrete with different crack widths and crack quantity are established and the control parameters are determined based on the nonsteady-state chloride migration (NSSCM) test. In addition, based on the concrete finite element models, influences of crack width, crack quantity, and erosion time on chloride migration behaviors and characteristics are studied. Furthermore, a prediction model of chloride concentration on the simulated surface of a rebar in concrete influenced by different crack states is established. This model is used to derive the corrosion current density and corrosion depth prediction models of a rebar in this paper, which can be used by engineers to estimate the migration behaviors of chloride and rebar corrosion degree in RC structures in a short time and evaluate the duration of RC structures after knowing the status of cracks and chloride diffusion sources.

The Chloride Ion Penetration Model Coupled with Temperature and Moisture Transfer in Marine Environment

2012 ◽  
Vol 591-593 ◽  
pp. 2422-2427
Author(s):  
Juan Zhao
Keyword(s):  
Marine Environment ◽  
Moisture Transfer ◽  
Regional Climate ◽  
Chloride Ion ◽  
Chloride Penetration ◽  
Chloride Diffusion ◽  
Tidal Zone ◽  
Analog Simulation ◽  
Chloride Ion Penetration ◽  
Ion Penetration

Considering the complexity of the chloride ion penetration in concrete exposed to marine environment, an integrated chloride penetration model coupled with temperature and moisture transfer is proposed. The governing equations and parameters embody fully the cross-impacts among thermal conduction, moisture transfer and chloride ion penetration. Furthermore, the four exposure conditions are classified based on the different contact with the aggressive marine environment, and then the micro-climate condition on the concrete surface is investigated according to the regional climate characteristics, therefore, a comprehensive analog simulation to the chloride penetration process is proposed. To demonstrate that the proposed numerical model can correctly simulate the chloride diffusion in concrete, the integrated chloride diffusion model is applied in reproducing a real experiment, finally the model gives good agreement with the experimental profiles, and it is proved the tidal zone exposure results in a more severe attack on the reinforcement

scholarly journals Airborne infection in a fully air-conditioned hospital: III. Transport of gaseous and airborne particulate material along ventilated passageways

1975 ◽  
Vol 75 (1) ◽  
pp. 45-56 ◽  
Author(s):  
O. M. Lidwell
Keyword(s):  
Mathematical Model ◽  
Flow Velocity ◽  
Effective Diffusion ◽  
Diffusion Constant ◽  
Particulate Material ◽  
Airborne Particulate ◽  
Airborne Infection ◽  
Directional Flow ◽  
A Value

SUMMARYA mathematical model is described for the transport of gaseous or airborne particulate material between rooms along ventilated passageways.Experimental observations in three hospitals lead to a value of about 0.06m.2/sec. for the effective diffusion constant in air without any systematic directional flow. The ‘constant’ appears to increase if there is any directional flow along the passage, reaching about 0.12 m.2/sec. at a flow velocity of 0.04 m./sec.Together with previously published methods the present formulae make it possible to calculate the expected average amounts of gaseous or particulate material that will be transported from room to room in ventilated buildings in which the ventilation and exchange airflows can be calculated.The actual amounts transported in occupied buildings, however, vary greatly from time to time.

Persistence of the electrophysiologic effects of mexiletine in canine Purkinje fibers alters the response to subsequent hypoxia

1987 ◽  
Vol 65 (10) ◽  
pp. 2104-2109
Author(s):  
Neil D. Berman ◽  
Richard I. Ogilvie ◽  
James E. Loukides
Keyword(s):  
Action Potential ◽  
Action Potential Duration ◽  
Free Solution ◽  
Purkinje Fibers ◽  
Subsequent Exposure ◽  
Hydrochloride Solution ◽  
Drug Free ◽  
Microelectrode Techniques ◽  
Upstroke Velocity ◽  
Normal Formula

The persistence of cellular electropharmacologic effects of mexiletine on canine Purkinje fibers was studied utilizing standard microelectrode techniques and two different protocols. In the first, the tissue was exposed to hypoxic perfusion before and 30 min after perfusion with one of the following: mexiletine hydrochloride 6.25 μM solution, mexiletine hydrochloride 12.5 μM solution, or drug-free Tyrode's solution. With the higher concentration of mexiletine, depression of the maximal upstroke velocity [Formula: see text] persisted 30 min after drug washout and subsequent exposure to hypoxia did not result in the anticipated shortening of action potential duration but did prevent the restoration of normal [Formula: see text]. After perfusion with the lower concentration of mexiletine, [Formula: see text] was not depressed and hypoxic action potential duration shortening was not prevented. In the second protocol, Purkinje fibers were perfused with 12.5 μM mexiletine hydrochloride solution and then exposed to hypoxia after 15, 30,45, or 60 min of perfusion with drug-free solution. Depression of maximal upstroke velocity and shortening of action potential duration persisted during washout, returning to control values by 45 min, although mexiletine was not detectable in the tissue bath after 10 min of washout. Hypoxia initiated at 15 or 30 min of washout failed to produce the anticipated shortening of action potential duration. At 45 and 60 min, action potential duration was shortened by hypoxia. We concluded that mexiletine depression of [Formula: see text] and shortening of action potential duration may persist in the absence of drug. Further shortening of action potential duration in response to hypoxia is prevented during this period. The persistence of [Formula: see text] depression is prolonged by hypoxia.

Effect of Stone Powder Content on the Diffusing Parameter and Diffusion Attenuation Coefficient of Chloride Ion of Mechanical Sand Concrete

2014 ◽  
Vol 584-586 ◽  
pp. 1818-1822
Author(s):  
Ming Qiang Qin ◽  
Wen Zhan ◽  
Wen Bing Xu ◽  
Jin Hui Li
Keyword(s):  
Attenuation Coefficient ◽  
Chloride Ion ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
River Sand ◽  
Moderate Amount ◽  
Powder Content ◽  
And Diffusion ◽  
Better Than

The effect of stone powder content on the chloride diffusion coefficient and diffusion attenuation coefficient of chloride ion of mechanical sand (MS) concrete was studied. The results showed that the resistance to chloride ion permeability of MS concrete firstly increased and then decreased with the increase of the content of stone powder. The anti-permeability of the concrete which had moderate amount of stone powder was better than that of the natural river sand (NS) concrete. The diffusion attenuation coefficient of MS concrete was greater than that of the NS concrete, which was good for long-term durability of concrete structure.

Diffusion study of chloride and binding of water in concrete pore by molecular dynamics simulation using LAMMPS

2021 ◽  
Vol 12 (3) ◽  
pp. 88
Author(s):  
Md. Shafiqul Islam ◽  
Sayem Ahmeed ◽  
Sumon Kumar Ghosh
Keyword(s):  
Diffusion Coefficient ◽  
Chloride Ion ◽  
System Size ◽  
Dynamics Simulation ◽  
Chloride Diffusion ◽  
Water Molecules ◽  
Chloride Diffusion Coefficient ◽  
Average Value ◽  
Temperature And Pressure ◽  
Different Characteristics

As for the communication between concrete and the particles, the surface shows Cl− shock and Na adsorption. With expanded particle focus, the solid adsorption capacity for Cl− is upgraded as a result of a detailed overview of the dynamic molecular simulation studies examining the chloride diffusion coefficient. Different characteristics of the diffusion process, including molecular models, system-size effects, temperature, and pressure conditions, and the type of protection, are discussed. This paper focus on Molecular Dynamic Simulation to determine the diffusion coefficient of chloride ion and water molecules in concrete. The diffusion coefficient for NaCl salt obtained 6.60178x10-10m2/s and the diffusion coefficient for CaCl2 salt obtained 7.29305x10-10m2/s. So, the average chloride diffusion coefficient 6.9475x10-10m2/s. Diffusion coefficient obtained from graph 5.562x10-10m2/s. Diffusion coefficients for water molecules for NaCl solution are 6.125x10-10m2/s, 6.85x10-10m2/s, 1.044x10-10m2/s, 8.525x10-10m2/s, 6.25x10-10m2/s. diffusion coefficient of water molecules in CaCl2 solution are 4.5x10-10m2/s, 6.725x10-10m2/s, 1.254x10-10m2/s, 7.725x10-10m2/s, 1.3x10-10m2/s. Average value obtained for water molecule diffusion are 4.545x10-10m2/s, 7.4062x10-10m2/s and 1.149x10-10m2/s. This diffusion of chloride effects the binding of water in concrete pore.

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