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Article

Roger Main

Roger Main gives a four‐part report on the optical technologies which are playing an increasingly important role in sensor development.

Abstract

Roger Main gives a four‐part report on the optical technologies which are playing an increasingly important role in sensor development.

Details

Sensor Review, vol. 7 no. 1
Type: Research Article
ISSN: 0260-2288

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Article

P. Roef

Optical fibre sensors are finding wide applications in biotechnology and medicine, as a European specialist explains.

Abstract

Optical fibre sensors are finding wide applications in biotechnology and medicine, as a European specialist explains.

Details

Sensor Review, vol. 7 no. 3
Type: Research Article
ISSN: 0260-2288

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Article

D.J. Mobbs and D. Summerhayes

Sensor Review publishes the results of a major sensor survey.

Abstract

Sensor Review publishes the results of a major sensor survey.

Details

Sensor Review, vol. 9 no. 2
Type: Research Article
ISSN: 0260-2288

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Article

Lujun Cui, Huichao Shang, Yan-long Cao and Gao-feng Zhou

Long life and high hydrogen sensitivity are the crucial performance parameters for an optical fiber hydrogen sensing membrane, and these are the fundamental areas of study…

Abstract

Purpose

Long life and high hydrogen sensitivity are the crucial performance parameters for an optical fiber hydrogen sensing membrane, and these are the fundamental areas of study for an optical fiber hydrogen sensor. Considering that a traditional optical fiber hydrogen sensor based on pure palladium cannot meet the expectations for long life and rapid sensitivity simultaneously, the experiment in this paper designed a kind of reflective optical fiber bundle hydrogen gas sensor based on a Pd0.75–Ag0.25 alloy to achieve a hydrogen sensing system. This paper aims to discuss the issues with this system.

Design/methodology/approach

A reflective optical fiber bundle hydrogen sensor was made up of an optical fiber bundle and a Pd0.75–Ag0.25 alloy hydrogen membrane. A combination of optical fiber light intensity measurements and the reference calculation method were used to extract the hydrogen concentration information from within the optical fiber, and the relationship between the hydrogen concentration changes and the reflective light intensity in the optical fiber was established.

Findings

The reflective optical fiber bundle hydrogen gas sensor based on a Pd–Ag alloy membrane was shown to provide an effective way to detect hydrogen concentrations. The experimental results showed that a 20-30-nm-thick Pd0.75–Ag0.25 alloy membrane could reach high hydrogen absorption and sensitivity. Key preparation parameters which included sputtering time and substrate temperature were used to prepare the hydrogen membrane during the DC sputtering process, and the reflectivity of the Pd–Ag alloy membrane was enough to meet the requirements of long life and high hydrogen sensitivity for the optical fiber hydrogen sensor.

Originality/value

This paper seeks to establish a foundation for optimizing and testing the performance of the Pd–Ag alloy hydrogen sensing membrane for an optical fiber bundle hydrogen sensor. To this end, the optimal thickness and key preparation parameters for the Pd–Ag alloy hydrogen sensing membrane were discussed. The results of this research have proved that the reflective optical fiber hydrogen sensor based on a Pd0.75–Ag0.25 alloy is an effective approach and precisely enough for hydrogen gas monitoring in practical engineering measurements.

Details

Sensor Review, vol. 37 no. 2
Type: Research Article
ISSN: 0260-2288

Keywords

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Article

Mohd Anwar Zawawi, Sinead O'Keffe and Elfed Lewis

The purpose of this paper is to provide a comparative review of intensity‐modulated fiber optic sensors with non‐optical sensors for health monitoring applications, from…

Abstract

Purpose

The purpose of this paper is to provide a comparative review of intensity‐modulated fiber optic sensors with non‐optical sensors for health monitoring applications, from the current research activities in the area.

Design/methodology/approach

A range of published research work in sensor design for four different health monitoring applications, including, lumbar spine bending, upper and lower limb motion tracking, respiration and heart rate monitoring, are presented and discussed in terms of their respective advantages and limitations.

Findings

This paper provides information on the various types of sensors applied into the health monitoring area. The sensing techniques of the fiber optic sensor for the stated applications are focused and compared in details to highlight their contributions.

Originality/value

A comparative review of published work is illustrated in an informative table content, to allow a clear idea of the current sensing approaches for health monitoring applications.

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Article

Roger P. Main

The use of fibre optic sensors is a relatively new development but the future applications are enormous

Abstract

The use of fibre optic sensors is a relatively new development but the future applications are enormous

Details

Sensor Review, vol. 5 no. 3
Type: Research Article
ISSN: 0260-2288

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Article

Qijing Lin, Zirong Wu, Na Zhao, Zhuangde Jiang, Qidong Zhang, Bian Tian and Peng Shi

The Fabry-Perot sapphire optical fiber sensor is an excellent choice for high-temperature sensing in civil and military fields, such as oil exploitation, engine and…

Abstract

Purpose

The Fabry-Perot sapphire optical fiber sensor is an excellent choice for high-temperature sensing in civil and military fields, such as oil exploitation, engine and turbine. The purpose of this paper is to study the high-reflective film system withstanding high temperature in Fabry-Perot sapphire optical fiber high-temperature sensor. To improve the performance of the sensor and reduce the difficulty of signal acquisition, one of the key ways is to enhance the normalized light intensity of F-P sensor, which can be achieved by coating the high-reflective film system on the fiber end.

Design/methodology/approach

The high-reflective film system can be achieved by a multilayer film with alternating ZrO2 and Al2O3 film layers whose refractive indexes are different. In addition, the optimum film alternating sequences and the influence of the number of film layers, incident angle and temperature should be obtained by numerical analysis.

Findings

With the increase of the number of film layers, the reflectivity rises gradually and the change trend is more and more gentle. A minimum of the spectral reflectivity will occur at a certain incident angle depending on the design of the periodic multilayer system. Temperature affects the reflectivity of high-reflective film system. The normalized light intensity of the F-P sensor coated with high-reflective film system enhances greatly which is helpful to the signal demodulation. The temperature response of the F-P sensor is mainly determined by the characteristics of the F-P cavity.

Originality/value

Higher reflectivity, lower cost and easy signal acquisition are the most important features of the introduced high-reflective film system for the Fabry-Perot sapphire optical fiber high-temperature sensor.

Details

Sensor Review, vol. 39 no. 2
Type: Research Article
ISSN: 0260-2288

Keywords

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Article

Shaoyi Xu, Fangfang Xing, Ruilin Wang, Wei Li, Yuqiao Wang and Xianghui Wang

At present, one of the key equipment in pillar industries is a large rotating machinery. Conducting regular health monitoring is important for ensuring safe operation of…

Abstract

Purpose

At present, one of the key equipment in pillar industries is a large rotating machinery. Conducting regular health monitoring is important for ensuring safe operation of the large rotating machinery. Because vibrations sensors play an important role in the workings of the rotating machinery, measuring its vibration signal is an important task in health monitoring. This paper aims to present these.

Design/methodology/approach

In this work, the contact vibration sensor and the non-contact vibration sensor have been discussed. These sensors consist of two types: the electric vibration sensor and the optical fiber vibration sensor. Their applications in the large rotating machinery for the purpose of health monitoring are summarized, and their advantages and disadvantages are also presented.

Findings

Compared with the electric vibration sensor, the optical fiber vibration sensor of large rotating machinery has unique advantages in health monitoring, such as provision of immunity against electromagnetic interference, requirement of less insulation and provision of long-distance signal transmission.

Originality/value

Both contact vibration sensor and non-contact vibration sensor have been discussed. Among them, the electric vibration sensor and the optical fiber vibration sensor are compared. Future research direction of the vibration sensors is presented.

Details

Sensor Review, vol. 38 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

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Article

Christine Connolly

To examine the range of fibreoptic sensors available for monitoring the integrity of buildings and civil engineering structures.

Abstract

Purpose

To examine the range of fibreoptic sensors available for monitoring the integrity of buildings and civil engineering structures.

Design/methodology/approach

Explains the need for structural monitoring and reviews the types of fibreoptic sensors. Concentrating on elongation and temperature sensing, shows how each technology works, which companies supply the products, and gives an overview of their technical specifications.

Findings

Fibre optics are able to provide integrated, single‐point and distributed sensor systems. The fibre is a communication channel as well as a sensor, and in some systems, carries highly multiplexed data over considerable distances to a central monitoring station. The take‐up of this technology in structural sensing is helped by appropriate packaging that assists attachment to buildings. Durability and measurement stability give a continuity of measurement that was not previously possible.

Originality/value

An introduction to the range of sensors applicable to structural monitoring, of general interest to scientists, but particularly to civil and constructional engineers.

Details

Sensor Review, vol. 26 no. 3
Type: Research Article
ISSN: 0260-2288

Keywords

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Article

Radislav Potyrailo and Sergei Golubkov

Achievements in guided wave optics have had a great influence on many areas of technology for several years. Fibre optic communication links, sensors for various…

Abstract

Achievements in guided wave optics have had a great influence on many areas of technology for several years. Fibre optic communication links, sensors for various parameters, recently developed distributed temperature sensors, integrated optical switches, etc. are all applications that are commercially available. The field of analytical chemistry is no exception in this growing technology. In order to compete with well‐established chemical‐sensing instrumentation, optical waveguide chemical sensors (OWCSs) must show all the qualities of such instrumentation. OWCSs combine well‐known features of sensors, based on waveguide optics, with optical methods of chemical analysis and offer advantages over other types of chemical sensor. OWCSs are electrically passive, corrosion‐resistant, can respond to analytes for which other chemical sensors are not available, and referencing can be carried out optically. They allow multicomponent measurements at several wavelengths, have a common technology for fabrication of sensors for different chemical and physical parameters and are easily compatible with telemetry etc. Further, only OWCSs are capable of distributed sensing. However, interference from ambient light, temperature, long‐term instability, relatively slow response time, and limited dynamic range may be a problem for some types of OWCS. These disadvantages can be considerably reduced using various methods.

Details

Sensor Review, vol. 12 no. 2
Type: Research Article
ISSN: 0260-2288

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