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Article

Ahmad Fairuz Omar

Visible and near infrared spectroscopy have been applied widely in fruits quality assessment especially on the measurement of soluble solids content (SSC) measured in o

Abstract

Purpose

Visible and near infrared spectroscopy have been applied widely in fruits quality assessment especially on the measurement of soluble solids content (SSC) measured in oBrix and acidity measured in pH. Spectroscopy technique has been applied on three botanically different categories of fruits, that is: imported Californian table grape, Mandarin lime and star fruit. The purpose is to examine the ability of spectroscopy technique to quantify internal quality parameters with very narrow variability due to the characteristics of the raw material analyzed. This work also presents comparative study on peak wavelengths that can best be used to calibrate SSC and pH of different types of fruits.

Design/methodology/approach

The effective wavelengths chosen for calibration development are compared with those selected by other researchers in similar experiments. NIR wavelengths 910 nm (C−H band) and 950 nm (O−H band) are the most important wavelengths for the prediction of SSC for all examined fruits while wavelengths 922‐923 nm and 990‐995 nm for pH. Visible wavelength 605, 675 and 654 nm can efficiently improve the SSC and pH prediction for grape, lime and star fruit, respectively.

Findings

The best prediction for SSC has been achieved with R2=0.953 and RMSE=0.182 for grape, R2=0.918 and RMSE=0.109 for lime and R2=0.957 and RMSE=0.354 for star fruit. The best prediction for pH has been achieved with R2=0.763 and RMSE=0.110 for grape, R2=0.841 and RMSE=0.073 for lime and R2=0.862 and RMSE=0.261 for star fruit.

Originality/value

Currently, the spectroscopy research conducted for the measurement of fruits qualities is conducted through wide range spectrometer. However, the peak responses are only located at specific wavelengths. Hence, the selection of wavelengths related to SSC and pH will allow the design of low cost instruments for the prediction of these internal quality parameters.

Details

Sensor Review, vol. 33 no. 3
Type: Research Article
ISSN: 0260-2288

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Article

Mahmoud M.A. Eid and Ahmed Nabih Zaki Rashed

The purpose of this study aims to simulate the long-period fiber grating sensor pulse peak position against the transmission range. The long-period fiber grating sensor…

Abstract

Purpose

The purpose of this study aims to simulate the long-period fiber grating sensor pulse peak position against the transmission range. The long-period fiber grating sensor pulse peak position against the transmission range is simulated clearly where the pulse peak value at zero position is 0.972655 with the ripple factor of unity. It is demonstrated that the long-period fiber grating sensor bandwidth can be estimated to be 50 µm. Wavelength shift of the long-period grating sensor (LPGS) is reported against grating wavelength, applied temperatures and applied micro strain.

Design/methodology/approach

This work has reported the numerical simulation of LPGS transmission spectrum behavior characteristics under the strain and temperature effects by using OptiGrating simulation software. The sensor fabrication material is silica-doped germanium. The transmittivity/reflectivity and input spectrum pulse intensity of long-period Bragg sensor variations are simulated against the grating wavelength variations. Input/output pulse intensity of LPGS variations is simulated against the timespan variations with the Gaussian input pulse from 100 to 500 km link length.

Findings

Temperature variation and strain variation of the LPGS are outlined against both applied temperatures and micro-strain variations at the central grating wavelength of 1,550 nm.

Originality/value

It is demonstrated that the long period fiber grating sensor bandwidth can be estimated to be 50 µm. Wavelength shift of the long period grating sensor is reported against both grating wavelength, applied temperatures and applied micro strain. Temperature variation and strain variation of the long period grating sensor are outlined against both applied temperatures and micro strain variations at the central grating wavelength of 1550 nm.

Details

Sensor Review, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0260-2288

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Article

Jiang Qi

The purpose of this paper is to compare the sensing characteristics of uniform fiber Bragg grating (FBG) and tilted fiber Bragg grating (TFBG) by presenting a detailed…

Abstract

Purpose

The purpose of this paper is to compare the sensing characteristics of uniform fiber Bragg grating (FBG) and tilted fiber Bragg grating (TFBG) by presenting a detailed research review. Temperature, axial strain, bending, vibration and refractive index measurands of FBG and TFBG sensor are presented and some significant differences are found.

Design/methodology/approach

Theoretical analysis and practical application in engineering are investigated and compared from other authors' research papers and self analysis. Spectra behavior of both FBG and TFBG are discussed.

Findings

There are found to be significant differences in temperature, axial strain, bending, vibration and refractive index sensing characteristics of FBG and TFBG.

Originality/value

The paper's analysis is comprehensive and clear and provides readers with the sensing characteristics of FBG and TFBG in detail.

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Article

M.J. Hird

One of the problems with curing films containing a titanium pigment with ultraviolet light is the rapid attenuation of the incident light by the pigment. This limits both…

Abstract

One of the problems with curing films containing a titanium pigment with ultraviolet light is the rapid attenuation of the incident light by the pigment. This limits both the pigmentation level and the thickness of film that can be effectively cured. In this study, the transmission by thin pigmented films of light of wavelength in the range 320–400 nm is measured experimentally. It is shown that the massive absorption of both the rutile and anatase forms of titanium dioxide in this region is responsible for the rapid attenuation of the light used to cure the films. The principal conclusion is that, given a constant lamp intensity and photoinitiator efficiency, the larger the wavelength of the light used to cure the film the greater will be the thickness of film that can be cured.

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Article

Yongxing Guo, Min Chen, Li Xiong, Xinglin Zhou and Cong Li

The purpose of this study is to present the state of the art for fiber Bragg grating (FBG) acceleration sensing technologies from two aspects: the principle of the…

Abstract

Purpose

The purpose of this study is to present the state of the art for fiber Bragg grating (FBG) acceleration sensing technologies from two aspects: the principle of the measurement dimension and the principle of the sensing configuration. Some commercial sensors have also been introduced and future work in this field has also been discussed. This paper could provide an important reference for the research community.

Design/methodology/approach

This review is to present the state of the art for FBG acceleration sensing technologies from two aspects: the principle of the measurement dimension (one-dimension and multi-dimension) and the principle of the sensing configuration (beam type, radial vibration type, axial vibration type and other composite structures).

Findings

The current research on developing FBG acceleration sensors is mainly focused on the sensing method, the construction and design of the elastic structure and the design of a new information detection method. This paper hypothesizes that in the future, the following research trends will be strengthened: common single-mode fiber grating of the low cost and high utilization rate; high sensitivity and strength special fiber grating; multi-core fiber grating for measuring single-parameter multi-dimensional information or multi-parameter information; demodulating equipment of low cost, small volume and high sampling frequency.

Originality/value

The principle of the measurement dimension and principle of the sensing configuration for FBG acceleration sensors have been introduced, which could provide an important reference for the research community.

Details

Sensor Review, vol. 41 no. 1
Type: Research Article
ISSN: 0260-2288

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Article

Lijun Meng, Xinyu Li and Xin Tan

A fiber Bragg grating (FBG) sensor was designed to measure the door gap of automobile bodies.

Abstract

Purpose

A fiber Bragg grating (FBG) sensor was designed to measure the door gap of automobile bodies.

Design/methodology/approach

The gap sensor was designed through a combination of the sliding wedge and cantilever beam, involving a magnetic force installation and arc structure of the force transmission point. Moreover, the sliding block adopted an anti-magnetic and wear-resistant material and the temperature compensation of the two FBGs was conducted. The magnetic force and contact stress of the sensor were examined to ensure that the sensor exhibited a certain magnetic attraction force and fatigue life. The performance of the gap sensor was examined experimentally.

Findings

The sensor could measure gaps with dimensions of 5 mm to 11 mm, with a sensitivity and measurement accuracy of 150.9 pm/mm and 0.0063% F.S., respectively. Moreover, the sensor exhibited a small gap sensitivity, with a repeatability error of 0.15%, anti-creep properties and magnetic interference abilities.

Originality/value

The sensor is compact and easy to install, as well as use for multiple sensor locations, with a maximum size of 43 mm, a mass of 26 g and installation type of magnetic suction. It can be used for high-precision static and dynamic measurements of the door inner clearance with a resolution of 0.013 mm to improve the efficiency of internal clearance on-line analysis and assembly quality inspection.

Details

Sensor Review, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0260-2288

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Article

Wenlong Liu, Yongxing Guo, Li Xiong and Yi Kuang

The purpose of this paper is to present the latest sensing structure designs and principles of information detection of fiber Bragg grating (FBG) displacement sensors…

Abstract

Purpose

The purpose of this paper is to present the latest sensing structure designs and principles of information detection of fiber Bragg grating (FBG) displacement sensors. Research advance and the future work in this field have been described, with the background that displacement and deformation measurements are universal and crucial for structural health monitoring.

Design/methodology/approach

This paper analyzes and summarizes the existing FBG displacement sensing technologies from two aspects principle of information detection (wavelength detection, spectral bandwidth detection, light intensity detection, among others) and principle of the sensing elastomer structure design (cantilever beam type, spring type, elastic ring type and other composite structures).

Findings

The current research on developing FBG displacement sensors is mainly focused on the sensing method, the construction and design of the elastic structure and the design of new information detection method. The authors hypothesize that the following research trends will be strengthened in future: temperature compensation technology for FBG displacement sensors based on wavelength detection; a study of more diverse elastic structures; and fiber gratings manufactured with special fibers will greatly improve the performance of sensors.

Originality/value

The latest sensing structure designs and principles of information detection of FBG displacement sensors have been proposed, which could provide important reference for research group.

Details

Sensor Review, vol. 39 no. 1
Type: Research Article
ISSN: 0260-2288

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Article

Nuria Lopez-Ruiz, Fernando Granados-Ortega, Miguel Angel Carvajal and Antonio Martinez-Olmos

In this work, the authors aim to present a compact low-cost and portable spectral imaging system for general purposes. The developed system provides information that can…

Abstract

Purpose

In this work, the authors aim to present a compact low-cost and portable spectral imaging system for general purposes. The developed system provides information that can be used for a fast in situ identification and classification of samples based on the analysis of captured images. The connectivity of the instrument allows a deeper analysis of the images in an external computer.

Design/methodology/approach

The wavelength selection of the system is carried out by light multiplexing through a light-emitting diode panel where eight wavelengths covering the spectrum from ultraviolet (UV) to near-infrared region (NIR) have been included. The image sensor used is a red green blue – infrared (RGB-IR) micro-camera controlled by a Raspberry Pi board where a basic image processing algorithm has been programmed. It allows the visualization in an integrated display of the reflectance and the histogram of the images at each wavelength, including UV and NIRs.

Findings

The prototype has been tested by analyzing several samples in a variety of applications such as detection of damaged, over-ripe and sprayed fruit, classification of different type of plastic materials and determination of properties of water.

Originality/value

The designed system presents some advantages as being non-expensive and portable in comparison to other multispectral imaging systems. The low-cost and size of the camera module connected to the Raspberry Pi provides a compact instrument for general purposes.

Details

Sensor Review, vol. 37 no. 3
Type: Research Article
ISSN: 0260-2288

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Article

James Yiming Zhang, Jing Wu, Gregor v. Bochmann and Michel Savoie

The purpose of this paper is to present the benefits of using the Lagrangian relaxation (LR) and subgradient methods in scenario studies for wavelength division…

Abstract

Purpose

The purpose of this paper is to present the benefits of using the Lagrangian relaxation (LR) and subgradient methods in scenario studies for wavelength division multiplexing (WDM) network planning. The problem of WDM network planning for a given set of lightpath demands in a mesh topology network is to select lightpath routes and then allocate wavelength channels to the lightpaths. In WDM network planning, a scenario study is to find out the network performance under different lightpath demands and/or different network resource configurations.

Design/methodology/approach

A scenario study must solve a series of related static WDM network planning problems. Each static WDM network planning problem is an optimization problem, and may be formulated as an integer linear programming problem, which can be solved by the proposed Lagrangian relaxation and subgradient methods. This paper uses the Lagrange multipliers that are obtained from previous scenarios as initial Lagrange multiplier values for other related scenarios.

Findings

This approach dramatically reduces the computation time for related scenarios. For small to medium variations of scenarios, the method reduces the computation time by several folds. The proposed method is the first method that effectively considers the relations between related scenarios, and uses such relations to improve the computation efficiency of scenario studies in WDM network planning.

Practical implications

The method improves the efficiency of a scenario study in WDM network planning. By using it, many “what‐if” type of scenario study questions can be answered quickly.

Originality/value

Unlike other existing methods that treat each scenario individually, this method effectively uses the information of the relation between different scenarios to improve the overall computation efficiency.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 28 no. 6
Type: Research Article
ISSN: 0332-1649

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Article

Ahmad Fairuz Omar, Wan Long Chiong, Wei Yee Tan and Jia Wen Wong

This paper aims to propose an area under the curve model to represent ultraviolet (UV) exposure doses on EBT3 films (in mJ/cm2). The model was developed on a cross-section…

Abstract

Purpose

This paper aims to propose an area under the curve model to represent ultraviolet (UV) exposure doses on EBT3 films (in mJ/cm2). The model was developed on a cross-section of the exposed films using visible absorbance method. Ultraviolet–A light emitting diodes (UVA–LEDs) with 20° and 60° half angle with distinctive peak emission wavelengths between 365 to 405 nm are used in this experiment. No similar experimental setup or findings have been reported thus far, though the various application of EBT3 for the measurement of solar UV (A + B) have been published since EBT3 is commercially available.

Design/methodology/approach

Two sets of UVA–LEDs were used as the UV radiation source in the experiment. The first set contains of four 5 mm low power UVA–LEDs with the 20° half angle and peak emission wavelength at 365, 375, 385 and 400 nm. The second set contains of five surface mount high power UVA–LEDs with the 60° half angle and peak emission wavelength at 365, 375, 385, 305 and 400 nm. The illumination setup for the two sets of LEDs is different between each other to obtain sufficient dose distribution on the films for spectroscopy analysis. This is due to the different illumination angle and irradiance intensity by each set of LEDs.

Findings

UV–LED with a peak emission of 365, 375 and 385 nm able to produce UV doses accurately measurable using EBT3 films, UVA–LEDs with peak emission at 395 nm and above produced much lower accuracy with R2. From both set of LEDs, it can be concluded that peak emission wavelength of UVA–LED does influence the discoloration of the films. Shorter wavelength (higher energy) of UVA–LEDs discolors EBT3 films much intense compared to longer wavelength for a given UV dose exposure.

Originality/value

Despite various practical applicability and advantages of UV–LEDs, there are still no standard methods in measuring UV–LED radiation output. The proposed approach not only allows us to obtain the dose of UV–LED, where the sensitivity of measurement is wavelength (energy) depended but also allows us to visually observe the illumination pattern of invisible UV radiation through the application of EBT3 films.

Details

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

Keywords

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