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Article
Publication date: 1 February 1979

P.P. NELSON

In order to obtain a universal description of neurons, we review the main experimental data in regard to gates, ionic channels and post‐synaptic pores. Some theoretical…

Abstract

In order to obtain a universal description of neurons, we review the main experimental data in regard to gates, ionic channels and post‐synaptic pores. Some theoretical discussions allow us to conclude that (a) the synaptic gates are always optimized to give a linear answer; (b) there is only one kind of sodium channels and gates; (c) there is only one kind of potassium gates in the somatic part of true neurons; (d) the delays in the opening of the gates differ slightly from one neuron to another; (e) the ionic concentrations inside the neurons are related to the values of these delays.

Details

Kybernetes, vol. 8 no. 2
Type: Research Article
ISSN: 0368-492X

Article
Publication date: 11 November 2013

Antonino Laudani, Salvatore Coco and Francesco Riganti Fulginei

The paper aims to illustrate the two kinds of analysis approach for which finite element method (FEM) can be successfully employed: the Poisson-Nernst-Planck (PNP) model and the…

Abstract

Purpose

The paper aims to illustrate the two kinds of analysis approach for which finite element method (FEM) can be successfully employed: the Poisson-Nernst-Planck (PNP) model and the Langevin-Lorentz-Poisson (LLP) one.

Design/methodology/approach

The approach of this work is to try making a survey of the use of the FEM in the modelling of charge transport/ion flow across membrane channels, in particular for the PNP analysis and for a particle based model such as LLP model.

Findings

In this paper, the two kinds of analysis approach for which FEM can be successfully employed, the PNP model and the LLP one, have been shown. In both cases the FEM is extremely useful to carry out these analysis and the simulation results obtained are in good agreement with experimental results.

Originality/value

The value of this paper is to demonstrate the FEM is extremely useful to carry out analysis and results which are in good agreement with experimental ones.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 32 no. 6
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 5 February 2018

Simona Di Fraia, Nicola Massarotti and P. Nithiarasu

This paper aims to provide a comprehensive literature review on modelling electro-osmotic flow in porous media.

Abstract

Purpose

This paper aims to provide a comprehensive literature review on modelling electro-osmotic flow in porous media.

Design/methodology/approach

Modelling electro-osmosis in fluid systems without solid particles has been first introduced. Then, after a brief description of the existing approaches for porous media modelling, electro-osmotic flow in porous media has been considered by analysing the main contributions to the development of this topic.

Findings

The analysis of literature has highlighted the absence of a universal model to analyse electro-osmosis in porous media, whereas many different methods and assumptions are used.

Originality/value

For the first time, the existing approaches for modelling electro-osmotic flow in porous have been collected and analysed to provide detailed indications for future works concerning this topic.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 28 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 2 January 2009

Robert Szmurlo, Jacek Starzynski, Stanislaw Wincenciak and Andrzej Rysz

The electric stimulation of the vagus nerve is used to obtain therapeutic results in epilepsy, depression and Alzheimer diseases. The purpose of this paper is to show numerical…

Abstract

Purpose

The electric stimulation of the vagus nerve is used to obtain therapeutic results in epilepsy, depression and Alzheimer diseases. The purpose of this paper is to show numerical model of stimulation, focusing on the mathematical approach to modeling a phenomenon of neural cells activation and its propagation in the nerve.

Design/methodology/approach

The paper presents a model based on the bidomain theory. It uses two continuous, averaged domains which depict the intra‐ and extra‐cellular domains and are connected with the membrane ionic currents. The numerical model uses 3D cylindrical model approximating the anatomical shape of the neck. The simulator is based on a time domain finite element method.

Findings

The presented approach allows to model the discrete behaviour of the membrane potential in the macroscopic, realistic model of the nerve. The validation of the parameters with the velocity of activation propagations suggests the strong disscussion on physical interpretation to the bidomain theory parameters. To obtain realistic results the parameters needed to be unrealistic.

Originality/value

The paper presents the combination of bidomain model of neural tissue with the time domain finite element method along with the atributes of bidomain model for realistic modeling of the process of propagtion of activation.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 28 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

Open Access
Article
Publication date: 29 June 2021

C. Ahamed Saleel, Saad Ayed Alshahrani, Asif Afzal, Maughal Ahmed Ali Baig, Sarfaraz Kamangar and T.M. Yunus Khan

Joule heating effect is a pervasive phenomenon in electro-osmotic flow because of the applied electric field and fluid electrical resistivity across the microchannels. Its effect…

594

Abstract

Purpose

Joule heating effect is a pervasive phenomenon in electro-osmotic flow because of the applied electric field and fluid electrical resistivity across the microchannels. Its effect in electro-osmotic flow field is an important mechanism to control the flow inside the microchannels and it includes numerous applications.

Design/methodology/approach

This research article details the numerical investigation on alterations in the profile of stream wise velocity of simple Couette-electroosmotic flow and pressure driven electro-osmotic Couette flow by the dynamic viscosity variations happened due to the Joule heating effect throughout the dielectric fluid usually observed in various microfluidic devices.

Findings

The advantages of the Joule heating effect are not only to control the velocity in microchannels but also to act as an active method to enhance the mixing efficiency. The results of numerical investigations reveal that the thermal field due to Joule heating effect causes considerable variation of dynamic viscosity across the microchannel to initiate a shear flow when EDL (Electrical Double Layer) thickness is increased and is being varied across the channel.

Originality/value

This research work suggest how joule heating can be used as en effective mechanism for flow control in microfluidic devices.

Details

Frontiers in Engineering and Built Environment, vol. 1 no. 2
Type: Research Article
ISSN: 2634-2499

Keywords

Article
Publication date: 2 August 2021

Lucie Zárybnická, Eliška Stránská, Kristýna Janegová and Barbora Vydrová

The study aims to focus on the preparation of a heterogeneous cation exchange membrane by a three-dimensional (3D) method – fused filament fabrication using a series of nozzles of…

Abstract

Purpose

The study aims to focus on the preparation of a heterogeneous cation exchange membrane by a three-dimensional (3D) method – fused filament fabrication using a series of nozzles of various diameters (0.4–1.0 mm). Polypropylene random copolymer (PPR) as a polymeric binder was mixed with 50 Wt.% of the selected conventional cation exchange resin, and a filament was prepared using a single screw mini extruder. Then filament was processed by FFF into the membranes with a defined 3D structure.

Design/methodology/approach

Electrochemical properties, morphology, mechanical properties and water absorption properties were tested.

Findings

Dependence of the tested properties on the used nozzle diameter was found. Both areal and specific resistances increased with increasing nozzle diameter. The same trend was also found for permselectivity. The optimal membrane with permselectivity above 90%, areal resistance of 8 O.cm2 and specific resistance of 124 O.cm2 was created using a nozzle diameter of 0.4 mm.

Originality/value

Using new materials for 3D print of cation exchange membrane with production without waste. The possibility of producing 3D membranes with a precisely defined structure and using a cheap 3D printing method. New direction of membrane structure formation. 3D-printed heterogeneous cation exchange membranes were prepared, which can compete with commercial membranes produced by conventional technologies. 3D-printed heterogeneous cation exchange membranes were prepared, which can compete with commercial membranes produced by conventional technologies.

Details

Rapid Prototyping Journal, vol. 27 no. 8
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 19 May 2012

Yajun Liu and Xianming Shi

The purpose of this paper is to provide a modeling perspective relevant to the use of cathodic prevention (CPre) for unconventional concrete in salt‐laden environment.

Abstract

Purpose

The purpose of this paper is to provide a modeling perspective relevant to the use of cathodic prevention (CPre) for unconventional concrete in salt‐laden environment.

Design/methodology/approach

Based on the experimentally obtained concrete resistivity and chloride diffusion coefficient data, numerical studies with the Nernst‐Planck equations were conducted to investigate the influence of applied voltage (magnitude, direction, and interruption), surface chloride concentration, and concrete mix design on the effectiveness of cathodic prevention and the distribution of ionic species in protected concrete.

Findings

The modeling results revealed that the direction of applied electric voltage has significant effect on the distributions of electrical potential and hydroxyl ions in the reinforced concrete, confirming the benefits of cathodic prevention in significantly increasing hydroxyl concentration near rebar and in slowing down the ingress of chloride ingress into concrete. The performance of intermittent CPre was found to be constrained by the variations in concrete resistance from the anode to the cathode. The model was also useful in illustrating the temporal and spatial evolutions on rebar surface in terms of oxygen, hydroxyl and chloride concentrations and electrical potential of top rebar, as well as such evolutions in concrete domain in terms of concrete resistivity and current density for each mix design.

Originality/value

The results reported herein shed light on the fundamental processes defining the performance of CPre for new unconventional concrete in salt‐laden environment.

Details

Anti-Corrosion Methods and Materials, vol. 59 no. 3
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 30 May 2019

Huiling Chen, Liguo Shuai, Weihang Zhu and Mei Miao

This paper aims to investigate the perception threshold (PT) of electrotactile stimulation under non-steady contact condition (NSCC) which is rarely considered in previous reports…

Abstract

Purpose

This paper aims to investigate the perception threshold (PT) of electrotactile stimulation under non-steady contact condition (NSCC) which is rarely considered in previous reports mainly because of the difficulty with experimental control. Three factors of NSCC are involved, including the current alternating frequency, the tapping interval of stimulation and the stimulating area of skin. The study is aimed at providing the basic PT data for design and application of wearable and portable electrotactile device.

Design/methodology/approach

The up-down method was selected to assess PT, and 72 experimental scenarios were constructed. During the study, we developed an experimental platform with the function of data record and programmable current stimulation. With psychophysical experiment, more than 10,000 data were collected. Furthermore, statics analysis and ANOVA test were opted for exploring the main factor influencing PT.

Findings

NSCC has different PTs on each body location, and PT has a positive correlation with frequency. In general, PT in NSCC is significantly lower than that in SCC. In some cases, it can be lower by more than 60 per cent. In addition, women have a lower PT than men across all age groups, and the younger is generally more sensitive than the older in electro-sensation.

Research limitations/implications

Limited factors of NSCC were considered in this study. Contact time and break interval should be investigated in the future work.

Practical implications

The paper includes implications for the development of smart electrotactile device.

Originality/value

This paper fulfills a challenge in assessing the PT under NSCC.

Details

Industrial Robot: the international journal of robotics research and application, vol. 46 no. 3
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 1 December 2006

E. Massad and A.F. Rocha

This second part of a companion paper seeks to extend the theory proposed to apply the hierarchy of fuzzy formal language to cope with the three major phenomenon of life…

Abstract

Purpose

This second part of a companion paper seeks to extend the theory proposed to apply the hierarchy of fuzzy formal language to cope with the three major phenomenon of life: replication, control and shuffling of genetic information.

Design/methodology/approach

In order to cope with the proposal, three new classes of FFG are proposed: replicating grammars: to formalize properties and consequences of DNA duplication; self‐controlled grammars: to provide the tools to control the grammar ambiguity and to improve adaptability, and recombinant grammars: to formalize properties and consequences of the sexual reproduction to life evolution. Considering all these facts, FFG are proposed as the key instrument to formalize the basic properties of the chemical transactions supporting life.

Findings

The formalism of the model provides a new way to analyze and interpret the findings of the different genome sequencing projects.

Originality/value

The theoretical framework developed here provides a new perspective of understanding the code of life and evolution.

Details

Kybernetes, vol. 35 no. 10
Type: Research Article
ISSN: 0368-492X

Keywords

Article
Publication date: 1 October 2006

A.F. Rocha and E. Massad

Since proposed by Darwin, evolution is considered to be dependent on a source of genetic variability that must be constrained by environmental conditions in order to generate…

Abstract

Purpose

Since proposed by Darwin, evolution is considered to be dependent on a source of genetic variability that must be constrained by environmental conditions in order to generate stable (adapted) phenotypes. Several sources and causes of this variability have been proposed so far. This paper aims to posit that ambiguity of fuzzy grammars is the main source of genetic variability on which natural selection operates.

Design/methodology/approach

Formal grammars (FG) were proposed as the tool to deal with human and artificial languages. Fuzzy formal grammars (FFGs) are the extension of the formalism in the Theory of Fuzzy Logic and are ambiguous grammars. Here, the ambiguity of the ordered set of chemical interactions – the so‐called signal transduction pathways (stp), linking membranes events to DNA reading and protein synthesis – is assumed as an inner source of variability that must be constrained by environmental conditions. Fuzzy formal languages (FFL) theory is used to mathematically formalize the biology concept of stp.

Findings

The genome variability is the result of the constraints imposed by the environment on the grammar intrinsic ambiguity.

Practical implications

The formalism of this model provides a new way to analyze and interpret the findings of the different genome sequencing projects.

Originality/value

The theoretical framework developed here provides a new perspective of understanding the code of life and evolution.

Details

Kybernetes, vol. 35 no. 9
Type: Research Article
ISSN: 0368-492X

Keywords

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