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1 – 10 of over 4000Yuan 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.
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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 propulsion…
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.
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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 membrane…
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.
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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.
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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 components…
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.
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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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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 membranes…
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.
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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.
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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…
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.
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Wan Xu, Xinsheng Liu, Huijuan Zhang, Ting Huo, Zhenbin Chen and Yuan Sun
This study aims to prepare an imprinted composite membrane with grafted temperature-sensitive blocks for the efficient adsorption and separation of rhenium(Re) from aqueous…
Abstract
Purpose
This study aims to prepare an imprinted composite membrane with grafted temperature-sensitive blocks for the efficient adsorption and separation of rhenium(Re) from aqueous solutions.
Design/methodology/approach
PVDF resin membrane was used as the substrate, dopamine and chitosan (CS) were used to modify the membrane surface and temperature-sensitive block PDEA was grafted on the membrane surface. Then acrylic acid (AA) and N-methylol acrylamide (N-MAM) were used as the functional monomers, ethyleneglycol dimethacrylate (EGDMA) as the cross-linker and ascorbic acid-hydrogen peroxide (Vc-H2O2) as the initiator to obtain the temperature-sensitive ReO4− imprinted composite membranes.
Findings
The effect of the preparation process on the performance of CS–Re–TIICM was investigated in detail, and the optimal preparation conditions were as follows: the molar ratios of AA–NH4ReO4, N-MAM and EGDMA were 0.13, 0.60 and 1.00, respectively. The optimal temperature and time of the reaction were 40 °C and 24 h. The maximum adsorption capacity of CS–Re–TIICM prepared under optimal conditions was 0.1071 mmol/g, and the separation was 3.90 when MnO4− was used as the interfering ion. The quasi first-order kinetics model and Langmuir model were more suitable to describe the adsorption process.
Practical implications
With the increasing demand for Re, the recovery of Re from Re-containing secondary resources becomes important. This study demonstrated a new material that could be separated and recovered Re in a complex environment, which could effectively alleviate the conflict between the supply and demand of Re.
Originality/value
This contribution provided a new material for the selective separation and purification of ReO4−, and the adsorption capacity and separation of CS–Re–TIICM were increased with 1.673 times and 1.219 time compared with other Re adsorbents, respectively. In addition, when it was used for the purification of NH4ReO4 crude, the purity was increased from 91.950% to 99.999%.
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