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Article

Mengna Cai, Hongyan Tian, Haitao Liu and Yanhui Qie

With the development of the modern technology and aerospace industry, the noise pollution is remarkably affecting people’s daily life and has been become a serious issue…

Abstract

Purpose

With the development of the modern technology and aerospace industry, the noise pollution is remarkably affecting people’s daily life and has been become a serious issue. Therefore, it is the most important task to develop efficient sound attenuation barriers, especially for the low-frequency audible range. However, low-frequency sound attenuation is usually difficult to achieve for the constraints of the conventional mass-density law of sound transmission. The traditional acoustic materials are reasonably effective at high frequency range. This paper aims to discuss this issue.

Design/methodology/approach

Membrane-type local resonant acoustic metamaterial is an ideal low-frequency sound insulation material for its structure is simple and lightweight. In this paper, the finite element method is used to study the low-frequency sound insulation performances of the coupled-membrane type acoustic metamaterial (CMAM). It consists of two identical tensioned circular membranes with fixed boundary. The upper membrane is decorated by a rigid platelet attached to the center. The sublayer membrane is attached with two weights, a central rigid platelet and a concentric ring with inner radius e. The influences of the distribution and number of the attached mass, also asymmetric structure on the acoustic attenuation characteristics of the CMAM, are discussed.

Findings

In this paper, the acoustic performance of asymmetric coupled-membrane metamaterial structure is discussed. The influences of mass number, the symmetric and asymmetry structure on the sound insulation performance are analyzed. It is shown that increasing the number of mass attached on membrane, structure exhibits low-frequency and multi-frequency acoustic insulation phenomenon. Compared with the symmetrical structure, asymmetric structure shows the characteristics of lightweight and multi-frequency sound insulation, and the sound insulation performance can be tuned by adjusting the distribution mode and location of mass blocks.

Originality/value

Membrane-type local resonant acoustic metamaterial is an ideal low-frequency sound insulation material for its structure is simple and lightweight. How to effectively broaden the acoustic attenuation band at low frequency is still a problem. But most of researchers focus on symmetric structures. In this study, the asymmetric coupled-membrane acoustic metamaterial structure is examined. It is demonstrated that the asymmetric structure has better sound insulation performances than symmetric structure.

Details

Multidiscipline Modeling in Materials and Structures, vol. 15 no. 5
Type: Research Article
ISSN: 1573-6105

Keywords

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Article

Yuan Kang, Ping‐Chen Shen, Cheng‐Hsign Chen, Yeon‐Pun Chang and Hsing‐Han Lee

This paper seeks to modify the determinations of flow rate and fluid resistance, which can be realized and confident from the measurements of flow rates in experiments.

Abstract

Purpose

This paper seeks to modify the determinations of flow rate and fluid resistance, which can be realized and confident from the measurements of flow rates in experiments.

Design/methodology/approach

According to coupled physics of solid membrane and lubrication fluid, finite element method is used simultaneously to determine membrane deflection and film thickness. Several cases are simulated by traditional method, finite element method and compared with experimental method for the flow rates and fluid resistances to present the modification of determination results.

Findings

The FEM results for the fixed eight‐section are approximated to actual flow rate and are consistent with the modified determination of the flow rates, and so the modified determinations of the flow rates are verified. When a computer of P4 with 1.8 GHz CPU and 512 MB RAM is utilized, time needed for traditional method or modified formula is fewer than one second. However, more than 4 h is required for FEM by using the same computer.

Originality/value

This study provides the modified method for the determinations of flow rate and fluid resistance in membrane‐type restrictors by using FEM. The FEM results can increase the determination accuracy of the flow rate and restriction coefficient in the design of membrane‐type restrictors.

Details

Industrial Lubrication and Tribology, vol. 59 no. 3
Type: Research Article
ISSN: 0036-8792

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Article

Rezia Molfino, Matteo Zoppi and Luca Rimassa

The purpose of this paper is to present a cost‐effective design for a new rescue robot locomotion module using the principle of a continuous sliding membrane to achieve…

Abstract

Purpose

The purpose of this paper is to present a cost‐effective design for a new rescue robot locomotion module using the principle of a continuous sliding membrane to achieve propulsion ratio (PR) near 1. Such high PR cannot be reached by other locomotion mechanisms that have been proposed.

Design/methodology/approach

The paper first introduces the PR as a reference parameter to assess locomotion effectiveness of snake‐ and worm‐like robots. The state‐of‐the‐art is reviewed. A direction to step beyond getting PR near 1 is indicated. The way is by realizing a continuous sliding membrane. Two solutions in this direction which have been recently proposed are recalled. It is shown that none of them can be practically implemented to realize functioning systems with today's available technology. A new design with membrane actuation has been identified and it is described in detail. A prototype has been realized and earliest results and evidence of functioning described.

Findings

Critical discussion of the concept of locomotion based on a sliding membrane was conducted. A new design for a robot locomotion module applying this concept was presented. Earliest evidence of functioning and effectiveness of the new system proposed was given.

Research limitations/implications

A new locomotion principle is shown. The state‐of‐the‐art background is discussed. A design to realize the new system in a cost‐effective way is described. The research implications lie in the future development of new mobile robots with higher locomotion capability than today's available systems. Several future research and development directions are shown.

Practical implications

A new generation of more locomotion‐effective snake‐ and worm‐robots, especially for rescue application in rubble, is foreseen. The design proposed takes cost‐effectiveness and practical realizability into account.

Originality/value

The continuous sliding membrane concept had been already proposed but no reasonable realization and actuation solutions had been singled out. The design of the new locomotion system is totally new and contains several breakthrough ideas. A prototype is available proving worthy in concept and functioning. It is cost‐effective and this will allow shorter application to real robots.

Details

Industrial Robot: An International Journal, vol. 35 no. 3
Type: Research Article
ISSN: 0143-991X

Keywords

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Article

Norihan Abdul Hamid, J. Yunas, B. Yeop Majlis, A.A. Hamzah and B. Bais

The purpose of this paper is to discuss the fabrication technology and test of thermo-pneumatic actuator utilizing Si3N4-polyimide thin film membrane. Thin film polyimide…

Abstract

Purpose

The purpose of this paper is to discuss the fabrication technology and test of thermo-pneumatic actuator utilizing Si3N4-polyimide thin film membrane. Thin film polyimide membrane capped with Si3N4 thin layer is used as actuator membrane which is able to deform through thermal forces inside an isolated chamber. The fabricated membrane will be suitable for thermo-pneumatic-based membrane actuation for lab-on-chip application.

Design/methodology/approach

The actuator device consisting of a micro-heater, a Si-based micro-chamber and a heat-sensitive square-shaped membrane is fabricated using surface and bulk-micromachining process, with an additional adhesive bonding process. The polyimide membrane is capped with a thin silicon nitride layer that is fabricated by using etch stop technique and spin coating.

Findings

The deformation property of the membrane depend on the volumetric expansion of air particles in the heat chamber as a result of temperature increase generated from the micro-heater inside the chamber. Preliminary testing showed that the fabricated micro-heater has the capability to generate heat in the chamber with a temperature increase of 18.8 °C/min. Analysis on membrane deflection against temperature increase showed that heat-sensitive thin polyimide membrane can perform the deflection up to 65 μm for a temperature increase of 57°C.

Originality/value

The dual layer polyimide capped with Si3N4 was used as the membrane material. The nitride layer allowed the polyimide membrane for working at extreme heat condition. The process technique is simple implementing standard micro-electro-mechanical systems process.

Details

Microelectronics International, vol. 32 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

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Article

Eliška Stránská, David Neděla, Jan Křivčík, Kristýna Weinertová and Natália Václavíková

The purpose of this paper is to examine the impact of thread count in polyester reinforcing fabric on heterogeneous cation exchange membrane mechanical properties and…

Abstract

Purpose

The purpose of this paper is to examine the impact of thread count in polyester reinforcing fabric on heterogeneous cation exchange membrane mechanical properties and electrochemical performance.

Design/methodology/approach

Seven polyester fabrics differing in thread count were used for membrane manufacture and mechanical properties such as ultimate force or ultimate strain of all fabrics and membranes were determined. Electrochemical and physical properties of produced membranes were evaluated as well.

Findings

It was found that with increasing weft density ultimate force became greater in the case of fabric and membrane as well. The impact of weft density on ultimate strain was not confirmed but changes in swelling ability mainly in width direction were observed. The assumption of worse electrochemical properties of membranes reinforced by fabric with lower open area was also validated and these membranes exhibited higher areal resistance.

Originality/value

Gained information is a useful tool in design process of new ion exchange membrane types with improved mechanical and swelling properties.

Details

International Journal of Clothing Science and Technology, vol. 30 no. 4
Type: Research Article
ISSN: 0955-6222

Keywords

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Article

G.V. Sahakyan, G.G. Artsruni and G.A. Poghosyan

The purpose of this paper was to reveal the possible changes in membrane physical parameters, such as surface charge, ξ-potential and molecular interactions of membrane

Abstract

Purpose

The purpose of this paper was to reveal the possible changes in membrane physical parameters, such as surface charge, ξ-potential and molecular interactions of membrane components due to the in vitro and in vivo influences of ESF.

Design/methodology/approach

The in vitro and in vivo (one hour) influences of 200 kV/m external electrostatic field (ESF) on the erythrocyte membranes of white outbred rats were investigated by spectrofluorometric, spectral and electrophoretic methods.

Findings

It was shown that the in vivo influence of ESF leads to the intermolecular reconstructions and decrease of the positive charged groups in membrane surface layer. At the same time, the increases of the negative charged groups of membrane proteins after the field influence, is revealed. The charge redistribution in membranes due to the in vitro influence of ESF is observed.

Originality/value

The analysis of literature data and generalization of data obtained allow us concluding that in parallel with the polarization of lipid component of bilayer the changes in the structural state of membrane proteins take place due to the ESF influence on the erythrocyte membranes. These changes can be the reason and/or the result of the ESF induced redistribution of membrane charge.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 34 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

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Article

Yuang Kang, Cheng‐Hsien Chen, Yi‐Chich Chen, Chi Chang and Shun‐Te Hsiao

The purpose of this paper is to present the identification method of restriction parameter and deformation parameter for membrane‐type restrictors.

Abstract

Purpose

The purpose of this paper is to present the identification method of restriction parameter and deformation parameter for membrane‐type restrictors.

Design/methodology/approach

A worktable mounting on the open‐type hydrostatic bearing is utilized to calibrate recess pressures for regulating outlet pressures of restrictors by changing the load and then both restrictor parameters can be identified from the measurements of the inlet pressure, the outlet pressure, and the flow rate of a restrictor by minimizing the difference between measured and identified flow rates. Furthermore, the influences of supply pressure and restrictor designs on both parameters are also studied.

Findings

An identification method for single‐action membrane‐type (SAM) restrictors is obtained directly from experimental results. The measurements of inlet pressure, outlet pressure, and flow rate of the restrictor are substituted into the combined equations for minimization of error between measured and identified flow rates to be solved for restriction and deformation parameters. The identified results show that both parameters can be described by polynomial functions of supply pressure. Both polynomials are regressed by curve fitting from identified results.

Originality/value

The paper shows how to calibrate inlet and outlet pressures of restrictors for designing a hydrostatic bearing system by changing supply pressure and load applied on worktable for the measurements of both pressure and the flow rate of restrictor.

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Article

G.V. Sahakyan, G.G. Artsruni and G.A. Poghosyan

The purpose of this paper is to investigate the in vitro influence of 200 kV/m electrostatic fields (ESF) on the microviscosity, viscosity and polarity of rat erythrocyte…

Abstract

Purpose

The purpose of this paper is to investigate the in vitro influence of 200 kV/m electrostatic fields (ESF) on the microviscosity, viscosity and polarity of rat erythrocyte membranes for revealing the possible changes in lipid-protein interactions due to the field influence.

Design/methodology/approach

The investigation of the parameters of erythrocyte membranes and their ghosts, particularly, their microviscosity, the amount and immersion degree of membrane proteins in lipid bilayer, polarity in depth of membrane and its viscosity carried out by the spectrofluorimetric method using the hydrophobic fluorescent probe pyrene.

Findings

The carried out investigations shown that the in vitro influence of ESF changes membrane microviscosity, the quantity of membrane peripheral proteins and their immersion degree in the lipid bilayer, if the ghosts have prepared from erythrocytes previously exposed in the field. The analysis of the same parameters for previously prepared erythrocyte ghosts exposed to the 200 kV/m ESF during an hour did not reveal any changes.

Originality/value

Data obtained and their comparison with the results of the previous works allow authors to conclude that the in vitro influence of ESF leads to the changes in the lipid-protein interactions in erythrocyte membranes.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 34 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

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Article

Peter Ball

Analyses some of the main ways in which microporous membranes can play a role in the efficient functioning of sensors. These devices are used to detect a property of, or…

Abstract

Analyses some of the main ways in which microporous membranes can play a role in the efficient functioning of sensors. These devices are used to detect a property of, or component in, a fluid in contact with the sensor. As used in this article, the term “sensor” is intended to cover the broadest range of optical, optoelectronic or electronic devices used to detect a component of a fluid in contact with the sensor as part of a detection system.

Details

Sensor Review, vol. 19 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Abstract

Purpose

The purpose of this paper is to purify the wastewater in the garment industry.

Design/methodology/approach

The preparation of the calcium alginate (CA)/activated carbon (AC) composite membrane was achieved by vacuum freeze-drying and the cross-linking reaction between sodium alginate and CaCl2. Effective parameters in the methylene blue (MB) adsorption such as temperature, dose, contact time and pH were discussed. The adsorption properties of the composite membrane were investigated by isotherm, kinetics and thermodynamic analysis. The adsorption equilibrium data were described by the adsorption isotherm Langmuir model and the Freundlich model. The pseudo-first-order, pseudo-second-order and intra-particle diffusion equations were selected to evaluate the kinetics. The thermodynamic study described that the adsorption reaction was spontaneous and exothermic.

Findings

The AC/CA membrane is an efficient and powerful adsorbent to remove MB in printing and dyeing wastewater, and provides a new idea for the selection of adsorption materials for industrial printing and dyeing wastewater.

Practical implications

The composite membrane research on CA and AC can provide new ideas for the research of these kinds of materials.

Social implications

The paper contributes to its wider and convenientapplication in wastewater treatment.

Originality/value

Studies on the combination of CA and AC into adsorption membranes and for the removal of dyes from printing and dyeing wastewater have not been reported. A novel composite material is provided for treatment dyeing wastewater in garment production. The composite membrane research on CA and AC can provide new ideas for the research of these kinds of materials and contribute to its wider and convenient application in wastewater treatment.

Details

International Journal of Clothing Science and Technology, vol. 32 no. 3
Type: Research Article
ISSN: 0955-6222

Keywords

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