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11 – 20 of 33K. Arshak, K. Twomey and D. Heffernan
This paper documents the development of a microcontroller‐based humidity sensing system. The humidity sensors are manufactured by thin film technology from a novel combination of…
Abstract
This paper documents the development of a microcontroller‐based humidity sensing system. The humidity sensors are manufactured by thin film technology from a novel combination of SiO/In2O3. The fabrication and characterization of the sensor samples is presented and discussed in this paper. The sensor pattern consists of an interdigitated conductor on top of which the sensing layer is deposited. A humidity sensitivity of 0.25%/RH% and a thermal sensitivity of 0.103%/°C has been measured. The samples exhibit a low drift over a one‐year time span (0.0013RH%/yr), low hysteresis (0.34RH%), good linearity (±2RH%) and a reasonably fast time response (18 sec). The entire sensor system has been analyzed mathematically and the necessary algorithms for error‐compensation have been developed. The resulting measurement system is efficient, accurate and flexible.
Behzad Bahraminejad, Shahnor Basri, Maryam Isa and Zarida Hambali
The purpose of this paper is to explore the ability of capillary‐attached gas sensor (CGS) in detecting components of gas mixtures, including a volatile organic gas and hydrogen…
Abstract
Purpose
The purpose of this paper is to explore the ability of capillary‐attached gas sensor (CGS) in detecting components of gas mixtures, including a volatile organic gas and hydrogen in a wide range of concentrations.
Design/methodology/approach
Diverse feature extraction and classification techniques were employed to analyze the response of CGS when applied to different mixtures.
Findings
It was observed that the response of CGS to the above gas mixtures could be distinguishable. While evaluating the results of the classification technique, it was implied that hydrogen, in the presence of the volatile organic gases, could be detected perfectly by analyzing the response of the CGS. Separating techniques, which yielded a high rate of classification, were used to separate mixtures containing hydrogen and organic gases from other organic gas mixtures without hydrogen.
Originality/value
The results presented in this paper prove the ability of CGS in fabricating an olfactory machine for analyzing the components of gas mixtures.
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K. Arshak, G.M. Lyons, C. Cunniffe, J. Harris and S. Clifford
This paper discusses the digital hardware and software that is required for data acquisition in a portable electronic nose (e‐nose) system. A review of current e‐nose systems is…
Abstract
This paper discusses the digital hardware and software that is required for data acquisition in a portable electronic nose (e‐nose) system. A review of current e‐nose systems is presented highlighting the methods employed by these systems to acquire the data from the sensor head.
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K. Arshak, E. Moore, G.M. Lyons, J. Harris and S. Clifford
This paper reviews the range of sensors used in electronic nose (e‐nose) systems to date. It outlines the operating principles and fabrication methods of each sensor type as well…
Abstract
This paper reviews the range of sensors used in electronic nose (e‐nose) systems to date. It outlines the operating principles and fabrication methods of each sensor type as well as the applications in which the different sensors have been utilised. It also outlines the advantages and disadvantages of each sensor for application in a cost‐effective low‐power handheld e‐nose system.
This work aims to improve upon the linearity of integrated CMOS current sensors used in switch mode power supply topologies, using a low-cost and low-voltage (less than 1.2 V…
Abstract
Purpose
This work aims to improve upon the linearity of integrated CMOS current sensors used in switch mode power supply topologies, using a low-cost and low-voltage (less than 1.2 V) CMOS technology node. Improved sensor accuracy contributes to efficiency in switched supplies by reducing measurement errors when it is integrated with closed-loop control.
Design/methodology/approach
Integrated current-sensing methods were investigated and CMOS solutions were prioritized. These solutions were implemented and characterized in the desired process and shortcomings were identified. A theoretical analysis accompanied by simulated tests was used to refine improvements which were prototyped. The current sensor prototypes were fabricated and tested.
Findings
Measured and simulated results are presented which show improved linearity in current sensor outputs. Techniques borrowed from analog amplifier design can be used to improve the dynamic range and linearity of current-steered CMOS pairs for measuring current. A current sensor with a gain of 5 V/A operating in a 10 MHz switch mode supply environment is demonstrated.
Originality/value
This paper proposes an alternative approach to creating suitable bias conditions for linearity in a SenseFET topology. The proposed method is compact and architecturally simple in comparison to other techniques.
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Susan Samadi, Ghasem Asadi Cordshooli, Mohammad Yousefi, Khadijeh Kalateh and SeyedAmirabbas Zakaria
This paper aims to introduce constructed CeO2/TiO2 core/shell nanoparticle as sensitive substance organic compounds.
Abstract
Purpose
This paper aims to introduce constructed CeO2/TiO2 core/shell nanoparticle as sensitive substance organic compounds.
Design/methodology/approach
The CeO2 nanoparticles were synthesized by hydrothermal treatment. Then CeO2/TiO2 core/shell was fabricated by sol–gel method preparation of TiO2 in the presence of ceria nanoparticles and applied as the sensitive material to make a sensor.
Findings
Formation of the nanoparticles was confirmed by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM). The synthesized sensor exhibited not only good sensitivity to volatile organic compounds at room temperature but also logarithm of sensitivity versus concentrations was linear.
Research limitations/implications
The sensor shows acceptable sensitivity to volatile organic compound at room temperature.
Practical implications
Experimental data revealed satisfactory reproducibility and short response and recovery times.
Originality/value
A radical mechanism for gas sensor reaction in two pathways was considered and activation energies were calculated by density functional theory (DFT) method to describe different sensitivities of tested volatile gases. The experimental results were consistent with the calculations.
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Syafiqah Ishak, Shazlina Johari, Muhammad Mahyiddin Ramli and Darminto Darminto
This review aims to give an overview about zinc oxide (ZnO) based gas sensors and the role of doping in enhancing the gas sensing properties. Gas sensors based on ZnO thin film…
Abstract
Purpose
This review aims to give an overview about zinc oxide (ZnO) based gas sensors and the role of doping in enhancing the gas sensing properties. Gas sensors based on ZnO thin film are preferred for sensing applications because of their modifiable surface morphology, very large surface-to-volume ratio and superior stability due to better crystallinity. The gas detection mechanism involves surface reaction, in which the adsorption of gas molecules on the ZnO thin film affects its conductivity and reduces its electrical properties. One way to enhance the gas sensing properties is by doping ZnO with other elements. A few of the common and previously used dopants include tin (Sn), nickel (Ni) and gallium (Ga).
Design/methodology/approach
In this brief review, previous works on doped-ZnO formaldehyde sensing devices are presented and discussed.
Findings
Most devices provided good sensing performance with low detection limits. The reported operating temperatures were within the range of 200̊C –400̊C. The performance of the gas sensors can be improved by modifying their nanostructures and/or adding dopants.
Originality/value
As of yet, a specific review on formaldehyde gas sensors based on ZnO metal semiconductors has not been done.
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Somaye Akbari, Mehdi Akbari, Mohammad Haghighat Kish and Firoz Mehr Mazaheri
The production of long-lasting fragrant semi-worsted fabrics using dendritic compounds as one of the nano size materials is concerned. Also quantitative assessments of the odour…
Abstract
Purpose
The production of long-lasting fragrant semi-worsted fabrics using dendritic compounds as one of the nano size materials is concerned. Also quantitative assessments of the odour intensity of the fragrant fabrics using an electronic-nose (E-nose) are made. The paper aims to discuss these issues.
Design/methodology/approach
The semi-worsted fabrics were perfumed using the second generation of polypropylene-imine (PPI) dendrimer as a host molecules. The ginseng and rosewater fragrances as guest molecules were applied into the PPI dendrimer to produce long-lasting fragrant fabrics. The odour intensity as well as long-lasting properties of the fragrant fabrics perfumed recently and the other sample perfumed one year ago were evaluated via E-nose fabricated in our laboratory. Physical properties of the fragrant fabrics were compared to the non-fragrant ones.
Findings
The interaction between ginseng and rosewater fragrances with the second generation of PPI dendrimer into the semi-worsted fabrics made a long-lasting fragrant fabrics without considerable impacts on bending length, air permeability and wrinkle recovery angles based on statistical analysis. However, the effects of making fragrant fabrics on the increasing weight are significant. In addition, the E-nose was successfully used to monitor the release of ginseng and rosewater fragrance from the fabrics by the response patterns of a temperature-modulated chemo-resistive gas sensor. E-nose analysis showed that the aroma intensity released from the old fragrant semi-worsted fabrics has no obvious diversity from that of new fragrant fabrics.
Originality/value
The findings suggest that the semi-worsted fabrics perfumed with dendritic materials revealed excellent sustained release property.
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Thomas Papakostas and Neil White
The use of polymer thick‐film technology for the implementation of piezoelectric sensors opens up the way towards the low‐cost production of piezoelectric sensing devices. A novel…
Abstract
The use of polymer thick‐film technology for the implementation of piezoelectric sensors opens up the way towards the low‐cost production of piezoelectric sensing devices. A novel polymer thick‐film piezoelectric paste is presented and compared with other piezoelectric materials. The main advantages of these films are the low processing temperature, their flexibility and the ease of creating patterns with feature sizes as small as 200μm. Various applications are proposed demonstrating the potential of these screen printable polymer piezoelectrics.
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