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Article

S. O'Keeffe, C. Fitzpatrick, E. Lewis and A.I. Al‐Shamma'a

The purpose of this paper is to provide a detailed review of radiation dosimetry techniques based on optical fibre dosimeters. It presents a comprehensive bibliography of…

Abstract

Purpose

The purpose of this paper is to provide a detailed review of radiation dosimetry techniques based on optical fibre dosimeters. It presents a comprehensive bibliography of the current research activities in the area.

Design/methodology/approach

A range of published work on optical fibre radiation dosimeters are presented, with the merits and limitations discussed. Each radiation dosimetry technique is discussed in turn, providing examples of dosimeters using such techniques reviewed. The main focus is on gamma radiation although other radiation dosimeters are considered.

Findings

This paper provides information on the wide range of research activity into radiation dosimeters. The dose ranges of these dosimeters are presented, along with the advantages and disadvantages of different dosimetry techniques.

Originality/value

A comprehensive review of published research in the area of solid radiation dosimetry is presented in this paper. It provides an individual with a review of the various techniques used and most recent research in that field.

Details

Sensor Review, vol. 28 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

D. Křemenáková, J. Militký, B. Meryová and V. Lédl

The main role of polymer optical fibers is to transmit light or optical signal to a specified spot. In the case of side emitting plastic optical fibers the light leaks out…

Abstract

The main role of polymer optical fibers is to transmit light or optical signal to a specified spot. In the case of side emitting plastic optical fibers the light leaks out from their surface. This sidelight can be used for creation of optically active textile structures providing opportunities to highlight people and objects without the need for external exposure. Due to the transmission loss, the intensity of radiation emitted in any direction decays exponentially along the fiber axis with increasing distance from the light source. The main aim of this contribution is evaluation of side emitting plastic optical fibers light intensity in dependence on the distance from light source. The special device for measurement of surface and cross section light intensity in various distances from light source was developed. The dependence of surface and cross section light intensity on the distance from light source will be expressed by the exponential type model with attenuation factor as the rate parameter. The influence of the optical fiber type and diameter on the attenuation factor of surface and cross section light intensity will be quantified.

Details

World Journal of Engineering, vol. 10 no. 3
Type: Research Article
ISSN: 1708-5284

Keywords

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Article

M. Batumalay, A. Lokman, H.A. Rahman, S.W. Harun and H. Ahmad

This paper aims to propose and demonstrate a simple fiber optic sensor using a tapered plastic multimode fiber as a probe for measurement of calcium nitrate concentrations…

Abstract

Purpose

This paper aims to propose and demonstrate a simple fiber optic sensor using a tapered plastic multimode fiber as a probe for measurement of calcium nitrate concentrations in de-ionized water.

Design/methodology/approach

The working mechanism is based on the observed increment in the transmission of the sensor that is immersed in calcium nitrate solution of higher concentration. The tapering of the plastic fiber is carried out by etching method using acetone, sand paper and de-ionized water.

Findings

Tapered fiber with diameter 0.45 mm gives the highest sensitivity of 0.028 mV/% due to better interaction between the evanescent field and the calcium nitrate solution with a good slope linearity of more than 98 per cent for a 1.07 per cent limit of detection in a straight probe arrangement. The use of calcium and nitrate ions within the sensing medium demonstrates the strong dependency of the sensor output trend on the electrolytic nature of the chemical solutions.

Originality/value

Demonstration of tapered plastic multimode fiber sensor probe for measurement electrolytic chemical solutions.

Details

Sensor Review, vol. 34 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

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Article

Ning Jing

This paper aims to propose a liquid level sensor with a multi-S-bend plastic optical fiber.

Abstract

Purpose

This paper aims to propose a liquid level sensor with a multi-S-bend plastic optical fiber.

Design/methodology/approach

The principle of liquid sensing used is based on the leakage of higher modes out of the fiber and repeated regeneration in the following bend sections. Therefore, a propagation loss was introduced in every bend section of the fiber with the loss depending on the refractive index of the environment.

Findings

Therefore, a continue shift in the liquid level can be detected by observing changes in the propagation loss of the fiber. The sensor features compactness and a flexible resolution.

Originality/value

Compared with the exited ones, the sensor has capability of continue liquid measurement and a greater measurement range.

Details

Sensor Review, vol. 39 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

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Article

Zi Guo, Fenghong Chu, Jinyu Fan, Ze Zhang, Zhenglan Bian, Gaofang Li and Xiaojun Song

The purpose of this paper is to propose and optimize plastic optical fiber (POF) probe with macro-bending biconical tapered structure for the relative humidity (RH) sensing.

Abstract

Purpose

The purpose of this paper is to propose and optimize plastic optical fiber (POF) probe with macro-bending biconical tapered structure for the relative humidity (RH) sensing.

Design/methodology/approach

In this study, the principle is the evanescent wave power modulated by the ambient humidity. The probe is fabricated by using fused biconical taper and heat-setting method and then coated with a fluorescent moisture-sensitive film.

Findings

The probe’s sensing performance can be optimized by changing the probe’s curvature radius, biconical tapered transition length and taper waist diameter. The result shows that the sensitivity of the probe is up to 1.60 and 3.40 mV/ per cent, respectively, at low humidity (10-45 per cent) and high humidity (45-90 per cent). Also, this probe has good linearity, repeatability, photostability and long-term stability.

Practical implications

The proposed probe can improve the sensitivity and linearity of RH sensing without complex devices, which is necessary for mass production, remote measurement and convenient operation.

Originality/value

POF probe with macro-bending biconical tapered structure is investigated in this paper, which is proved to be effective in improving the sensitivity and linearity.

Details

Sensor Review, vol. 39 no. 3
Type: Research Article
ISSN: 0260-2288

Keywords

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Article

M. Yasin, H.A. Rahman, N. Bidin, S.W. Harun and H. Ahmad

The purpose of this paper is to demonstrate a simple design of a fiber optic displacement sensor using a multimode plastic fiber coupler based on reflective intensity…

Abstract

Purpose

The purpose of this paper is to demonstrate a simple design of a fiber optic displacement sensor using a multimode plastic fiber coupler based on reflective intensity modulation technique.

Design/methodology/approach

The performances of this sensor are investigated by correlating the detector output with different light sources, coupling ratios and various real objects with different reflectivity properties namely aluminum, brass and copper. In contrast to the output profile produced by probes with multiple fibers placed adjacently together, this sensor uses only one fiber for sending and receiving the light and therefore only the back slope exists.

Findings

Aluminum exhibit the highest performance among the real objects when coupled with a red He‐Ne laser and a coupling ratio of 50:50 with a sensitivity, linear range, resolution and dynamic range of 1.7 mV/mm, 1.5 mm, 16 μm, and 5.0 mm, respectively.

Originality/value

This is the first demonstration of a fiber optic displacement sensor using fiber coupler probe with successful examination of the correlation between the detector output, variation in coupling ratios and reflectivity properties of the tested real objects.

Details

Sensor Review, vol. 32 no. 3
Type: Research Article
ISSN: 0260-2288

Keywords

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Article

Dana Křemenáková, Barbora Meryová, Jiří Militký and Vít Lédl

The main aim of this work is evaluation of side emitting plastic optical fibers (POF) illumination intensity changes in dependence on the distance from light source…

Abstract

The main aim of this work is evaluation of side emitting plastic optical fibers (POF) illumination intensity changes in dependence on the distance from light source. Illumination intensity is measured along straight and bent fibers. The special devices for these measurements realization are described. The dependence of light intensity on the distance from light source for straight optical fibers is expressed by the exponential type model with two parameters, i.e. illumination intensity at the input into fiber and fiber attenuation factor. Preliminary results of measurement of light intensity in bent state are discussed. Influence of ratio between fiber diameter and bending cylinder diameter on the illumination intensity changes is presented.

Details

World Journal of Engineering, vol. 10 no. 3
Type: Research Article
ISSN: 1708-5284

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Article

Paulo Costa Antunes, João Miguel Dias, Humberto Varum and Paulo André

In this work, the paper aims to demonstrate the feasibility of plastic optical fiber (POF) based accelerometers for the structural health monitoring (SHM) of civil…

Abstract

Purpose

In this work, the paper aims to demonstrate the feasibility of plastic optical fiber (POF) based accelerometers for the structural health monitoring (SHM) of civil engineering structures based on measurements of their dynamic response, namely to estimate natural frequencies. These sensors use POFs, combining the advantages of the optical technology with the robustness of this particular kind of fiber. The POF sensor output is directly compared with the signal from an electrical sensor, demonstrating the potential use of such sensors in structural monitoring applications.

Design/methodology/approach

Within this work, the paper demonstrates the feasibility of using a low-cost acceleration system based on a POF accelerometer on the dynamic monitoring of a civil engineering structure, aiming its natural frequency evaluation, which is a primary parameter to be used in SHM methods and numerical models calibration.

Findings

A low-cost POF-based accelerometer was used in the characterization of a civil engineering structural component, located in a building at the University of Aveiro Campus, being used to estimate its natural frequency with a relative error of 0.36 percent, comparatively to the value estimated recurring to a calibrated electronic sensor.

Originality/value

Optical fiber sensors take advantage of the fibers properties, such as immunity to electromagnetic interference and electrical isolation. They are very attractive for use in hostile environments, like submerse environments or flammable atmospheres where electrical currents might pose a hazard. The advantages of POF itself should also be considered, like resistance to hash environments, robustness, flexibility, low-cost interrogation units and high numeric aperture (lower cost components). The paper demonstrates the feasibility of using a low-cost acceleration system based on a POF accelerometer on the dynamic monitoring of a civil engineering structure, aiming its natural frequency evaluation.

Details

Sensor Review, vol. 34 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

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Article

Malathy Batumalay, F. Ahmad, Asiah Lokman, A.A. Jasim, Sulaiman Wadi Harun and H. Ahmad

A simple tapered plastic optical fiber (POF) sensor is proposed and demonstrated for measurement of uric acid concentrations in de-ionized water. The paper aims to discuss…

Abstract

Purpose

A simple tapered plastic optical fiber (POF) sensor is proposed and demonstrated for measurement of uric acid concentrations in de-ionized water. The paper aims to discuss these issues.

Design/methodology/approach

The sensor operates based on intensity modulation technique as the tapered POF probe which was coated by a single walled carbon nonotubes polyethylene oxide (SWCNT-PEO) composite is immersed into the uric acid solution. The probe was fabricated using an etching method and has a waist diameter of 0.46 mm and tapering length of 10 mm.

Findings

As the concentration varies from 0 to 500 ppm, the output voltage of the sensor increases linearly from 6.13 to 7.35 mV with a sensitivity of 0.0023 mV/% and a linearity of more than 97.20 percent. The SWCNT-PEO composite coating increases the sensitivity of the proposed sensor due to the effective cladding refractive index, which increases with the coating and thus allows more light to be transmitted from the tapered fiber.

Originality/value

This is the first demonstration of the tapered POF sensor for measurement of uric acid concentrations in de-ionized water.

Details

Sensor Review, vol. 34 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

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