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Détails du magazine
Format
Magazine
eISSN
1178-5608
Première publication
01 Jan 2008
Période de publication
1 fois par an
Langues
Anglais

Chercher

Volume 3 (2010): Edition 1 (January 2010)

Détails du magazine
Format
Magazine
eISSN
1178-5608
Première publication
01 Jan 2008
Période de publication
1 fois par an
Langues
Anglais

Chercher

10 Articles
Accès libre

Highly Sensitive Porous Silicon Sensor: Detection of Organic Vapours Using Photoluminescence Quenching Technique

Publié en ligne: 13 Dec 2017
Pages: 1 - 13

Résumé

Abstract

Porous silicon based sensors were tested in the presence of various linear aliphatic alcohols (methanol to n-hexanol) and water in the range of 10-100 ppm by photoluminescence quenching technique. An increasing trend in the degree of quenching was observed with the chain length of alcohols while minimum response was given to water. Sensitivity as high as 80-90% and nearly instant response time has proven the sensors to be highly efficient. Photoluminescence quenching phenomena is discussed on the basis of charge transfer mechanism between the host and the vapour-induced surface states, but the degree of quenching and anomalous response as a function of chain length suggests no unique quenching theory for estimating the sensitivity for the set of alcohols tested. From methanol to butanol, the sensitivity was dependent on the effective concentration of analytes in the porous silicon matrix, while for pentanol and hexanol having high boiling point, the sensitivity was linked to dielectric quenching mechanism due to the condensation of vapours inside the pores.

Mots clés

  • organic vapour
  • photoluminescence quenching
  • porous silicon
  • Raman
  • sensor
Accès libre

New Method To Assess Service Quality in Care Homes For The Elderly

Publié en ligne: 13 Dec 2017
Pages: 14 - 26

Résumé

Abstract

A simple but dependable electronic device, Con-Dis, has been developed to gain reliable information on elderly persons’ perceptions of their well-being. The device has been tested and proven to be technically functional and dependable. It was tested in two care homes for the elderly and two private homes to evaluate whether it provided reliable information about the service quality. This report illustrates the practical usage of the device and shows its efficiency in gathering reliable service quality information from the focus group. The results suggest that Con-Dis is suitable for measuring the perceived service quality and seems to reduce the risk of too-positive evaluations.

Mots clés

  • Monitoring system
  • service quality
  • electronic device
  • care home for the elderly
  • Con-Dis
Accès libre

Lamb Wave Based Monitoring of Plate-Stiffener Deboding using a Circular Array of Piezoelectric Sensors

Publié en ligne: 13 Dec 2017
Pages: 27 - 44

Résumé

Abstract

In this paper we propose an efficient way of localization and parametric identification of metallic plate-stiffener debonding. A concept and experimental results based on a circular array of Piezoelectric Wafer Active Sensors (PWASs) is presented. Implementation of this circular array of PWASs combines the Lamb wave technique and symmetry breaking in the signal pattern to monitor the growth of a debonding of a stiffener on a metallic plate. Wavelet time-frequency maps of the sensor signals are employed and a damage index is plotted against the damage parameters for frequency sweep of the excitation signal (a windowed sine signal). Wavelet coefficient in time gives an insight regarding the effect of debonding growth on the Lamb wave transmission in time-frequency scale. We present here a method to eliminate the time scale effect which helps in identifying easily the signature of damage in the measured signals including the reflection from the boundary of the plate. The proposed method becomes useful in determining the approximate location of the damage with respect to the location of three neighboring sensors in the circular array. A cumulative damage index is computed for varying damage sizes and the results appear promising.

Mots clés

  • Circular array
  • piezoelectric
  • wavelet
  • damage index
  • lamb wave
  • plate
  • debonding
Accès libre

Application of Intelligent Controller in a Ball and Beam Control System

Publié en ligne: 13 Dec 2017
Pages: 45 - 60

Résumé

Abstract

Ball and beam system is one of a nonlinear and unstable control system, thus providing a challenge to the control engineers and researchers. There are a number of controllers which have been studied for years that can be used to stabilize the ball and beam system. This paper investigates the performance of few different control approaches that consist of conventional controller, modern controller and intelligent controller for a ball and beam system. It will involve the derivation of the mathematical modeling that includes the linearization of the model in order to be used with the linear controllers. The works followed with designing those controllers and simulating it in MATLAB. Each controller performance will be analyzed and compared which is based on common criteria’s of the step response. An appropriate graphic user interface (GUI) has been developed to view the animation of the ball and beam system.

Mots clés

  • ball beam
  • modeling
  • PID controller
  • LQR controller
  • neural network controller
Accès libre

Sensors for Monitoring Components, Systems and Processes

Publié en ligne: 13 Dec 2017
Pages: 61 - 74

Résumé

Abstract

The application of sensors encompasses many sectors of industry. In this paper, we outline different sensors – Raman distributed temperature sensor, sensor based on nano ferrofluids and MEMS based ultrasonic sensors. The development and application of these sensors for monitoring performance of systems and processes are discussed. Further, we also discuss the application of acoustic emission and infrared thermal imaging for process monitoring.

Mots clés

  • Fiber optic sensor
  • nano ferrofluids
  • MEMS
  • ultrasonic sensor
  • Acoustic emission
  • thermal imaging
Accès libre

Non-Invasive Characterization of total Hip Arthroplasty by Means of Passive Acceleration Measurement

Publié en ligne: 13 Dec 2017
Pages: 75 - 87

Résumé

Abstract

This paper presents a non-invasive measurement method to detect and characterize failures and material imperfections in total joint prostheses based on acceleration measurement. Therefore, a prototype sensor has been developed to fulfill the requirements of a medical-technical sensor. This sensor has been tested on patients with total hip arthroplasty. Special emphasis is put on the real-time processing of measurement data by means of intelligent signal processing as well as reliable and repeatable measurement procedures, including standardized positions for the sensor front-end and a standardized motion-sequence the patient is performing.

Mots clés

  • Total hip arthroplasty
  • Non-invasive measurement
  • Failure characterization
  • Acceleration measurement
  • wear detection
Accès libre

An Extensive Study, Design and Simulation of Mems Guided Media: Microstrip Line

Publié en ligne: 13 Dec 2017
Pages: 88 - 93

Résumé

Abstract

In this paper, some design issues of one of the planar-guided media known as Microstrip line has been presented. The main purpose of this paper is to study the fundamental transmission properties of the microstrip line in view of varying the length, materials used for device formation/fabrication and highest frequency of operation. The paper is mainly divided in to two portions; first portion deals with theoretical portion because, it is necessary to know how the characteristic impedance, phase velocity, and attenuation constant of the dominant mode of microstrip depend on geometrical factors, on the electronic properties of substrate and conductors used, and on the frequency. Since this is a “mixed” dielectric system, the TEM mode can not be supported [2] and the second portion of the investigation was devoted to the effect of variation of length and frequency on the RF performance of the line. Although many papers are available on this topic, but the issues described in this paper have somewhat different point of view.

Mots clés

  • RF MEMS
  • TEM mode
  • HRS
  • TFMLs
Accès libre

Development and Characterization of Surface Micro-Machined MEMS Based Varactor

Publié en ligne: 13 Dec 2017
Pages: 94 - 107

Résumé

Abstract

This paper presents complete behavioral analysis of a surface micro-machined MEMS varactor for frequency tuning application in voltage controlled oscillators in RF applications with high Quality factor and tunability. The dimensions of the MEMS device have been optimized with Finite Element Method based CoventorWare analysis and verified through lumped parameter analysis in Saber platform. The MEMS varactor has been fabricated with the PolyMUMPs process. The paper also describes the Mechanical and electrical characterization of the MEMS varactor to meet the designed specification.

Mots clés

  • MEMS
  • varactor
  • VCO
  • capacitance tuning ratio
  • pull-in
  • SEM
  • vibration spectrum
  • LDV
Accès libre

Fiber Bragg Grating Sensors: New Ideas on Straintemperature Discrimination

Publié en ligne: 13 Dec 2017
Pages: 108 - 117

Résumé

Abstract

In this paper, two novel methods are discussed, wherein Fiber Bragg Gratings are used as sensors to discriminate strain and temperature, simultaneously. These methods provide a good linear response and involve simple fabrication & implementation of the sensors.

Mots clés

  • Fiber Bragg grating sensors
  • strain sensor
  • temperature sensor
  • strain and temperature discrimination
Accès libre

Microstructuring of SU-8 Resist for MEMS and Bio-Applications

Publié en ligne: 13 Dec 2017
Pages: 118 - 129

Résumé

Abstract

Some studies on the fabrication of micro-needles, micro-pillers, and micro-channels using SU-8 negative photoresist for MEMS and bio-applications are reported. The SU-8 processing technology was standardized for the purpose. Micro-pillars were fabricated on SU-8 polymer by soft lithographic technique. Micro-needles were realized on SU-8 film utilizing lensing effect of the etched groove structure of the glass substrate. Micro-channel was fabricated by molding of PDMS polymer on patterned SU-8 ridge structure. Structural characterization of the fabricated structures were investigated using optical microscope and SEM.

10 Articles
Accès libre

Highly Sensitive Porous Silicon Sensor: Detection of Organic Vapours Using Photoluminescence Quenching Technique

Publié en ligne: 13 Dec 2017
Pages: 1 - 13

Résumé

Abstract

Porous silicon based sensors were tested in the presence of various linear aliphatic alcohols (methanol to n-hexanol) and water in the range of 10-100 ppm by photoluminescence quenching technique. An increasing trend in the degree of quenching was observed with the chain length of alcohols while minimum response was given to water. Sensitivity as high as 80-90% and nearly instant response time has proven the sensors to be highly efficient. Photoluminescence quenching phenomena is discussed on the basis of charge transfer mechanism between the host and the vapour-induced surface states, but the degree of quenching and anomalous response as a function of chain length suggests no unique quenching theory for estimating the sensitivity for the set of alcohols tested. From methanol to butanol, the sensitivity was dependent on the effective concentration of analytes in the porous silicon matrix, while for pentanol and hexanol having high boiling point, the sensitivity was linked to dielectric quenching mechanism due to the condensation of vapours inside the pores.

Mots clés

  • organic vapour
  • photoluminescence quenching
  • porous silicon
  • Raman
  • sensor
Accès libre

New Method To Assess Service Quality in Care Homes For The Elderly

Publié en ligne: 13 Dec 2017
Pages: 14 - 26

Résumé

Abstract

A simple but dependable electronic device, Con-Dis, has been developed to gain reliable information on elderly persons’ perceptions of their well-being. The device has been tested and proven to be technically functional and dependable. It was tested in two care homes for the elderly and two private homes to evaluate whether it provided reliable information about the service quality. This report illustrates the practical usage of the device and shows its efficiency in gathering reliable service quality information from the focus group. The results suggest that Con-Dis is suitable for measuring the perceived service quality and seems to reduce the risk of too-positive evaluations.

Mots clés

  • Monitoring system
  • service quality
  • electronic device
  • care home for the elderly
  • Con-Dis
Accès libre

Lamb Wave Based Monitoring of Plate-Stiffener Deboding using a Circular Array of Piezoelectric Sensors

Publié en ligne: 13 Dec 2017
Pages: 27 - 44

Résumé

Abstract

In this paper we propose an efficient way of localization and parametric identification of metallic plate-stiffener debonding. A concept and experimental results based on a circular array of Piezoelectric Wafer Active Sensors (PWASs) is presented. Implementation of this circular array of PWASs combines the Lamb wave technique and symmetry breaking in the signal pattern to monitor the growth of a debonding of a stiffener on a metallic plate. Wavelet time-frequency maps of the sensor signals are employed and a damage index is plotted against the damage parameters for frequency sweep of the excitation signal (a windowed sine signal). Wavelet coefficient in time gives an insight regarding the effect of debonding growth on the Lamb wave transmission in time-frequency scale. We present here a method to eliminate the time scale effect which helps in identifying easily the signature of damage in the measured signals including the reflection from the boundary of the plate. The proposed method becomes useful in determining the approximate location of the damage with respect to the location of three neighboring sensors in the circular array. A cumulative damage index is computed for varying damage sizes and the results appear promising.

Mots clés

  • Circular array
  • piezoelectric
  • wavelet
  • damage index
  • lamb wave
  • plate
  • debonding
Accès libre

Application of Intelligent Controller in a Ball and Beam Control System

Publié en ligne: 13 Dec 2017
Pages: 45 - 60

Résumé

Abstract

Ball and beam system is one of a nonlinear and unstable control system, thus providing a challenge to the control engineers and researchers. There are a number of controllers which have been studied for years that can be used to stabilize the ball and beam system. This paper investigates the performance of few different control approaches that consist of conventional controller, modern controller and intelligent controller for a ball and beam system. It will involve the derivation of the mathematical modeling that includes the linearization of the model in order to be used with the linear controllers. The works followed with designing those controllers and simulating it in MATLAB. Each controller performance will be analyzed and compared which is based on common criteria’s of the step response. An appropriate graphic user interface (GUI) has been developed to view the animation of the ball and beam system.

Mots clés

  • ball beam
  • modeling
  • PID controller
  • LQR controller
  • neural network controller
Accès libre

Sensors for Monitoring Components, Systems and Processes

Publié en ligne: 13 Dec 2017
Pages: 61 - 74

Résumé

Abstract

The application of sensors encompasses many sectors of industry. In this paper, we outline different sensors – Raman distributed temperature sensor, sensor based on nano ferrofluids and MEMS based ultrasonic sensors. The development and application of these sensors for monitoring performance of systems and processes are discussed. Further, we also discuss the application of acoustic emission and infrared thermal imaging for process monitoring.

Mots clés

  • Fiber optic sensor
  • nano ferrofluids
  • MEMS
  • ultrasonic sensor
  • Acoustic emission
  • thermal imaging
Accès libre

Non-Invasive Characterization of total Hip Arthroplasty by Means of Passive Acceleration Measurement

Publié en ligne: 13 Dec 2017
Pages: 75 - 87

Résumé

Abstract

This paper presents a non-invasive measurement method to detect and characterize failures and material imperfections in total joint prostheses based on acceleration measurement. Therefore, a prototype sensor has been developed to fulfill the requirements of a medical-technical sensor. This sensor has been tested on patients with total hip arthroplasty. Special emphasis is put on the real-time processing of measurement data by means of intelligent signal processing as well as reliable and repeatable measurement procedures, including standardized positions for the sensor front-end and a standardized motion-sequence the patient is performing.

Mots clés

  • Total hip arthroplasty
  • Non-invasive measurement
  • Failure characterization
  • Acceleration measurement
  • wear detection
Accès libre

An Extensive Study, Design and Simulation of Mems Guided Media: Microstrip Line

Publié en ligne: 13 Dec 2017
Pages: 88 - 93

Résumé

Abstract

In this paper, some design issues of one of the planar-guided media known as Microstrip line has been presented. The main purpose of this paper is to study the fundamental transmission properties of the microstrip line in view of varying the length, materials used for device formation/fabrication and highest frequency of operation. The paper is mainly divided in to two portions; first portion deals with theoretical portion because, it is necessary to know how the characteristic impedance, phase velocity, and attenuation constant of the dominant mode of microstrip depend on geometrical factors, on the electronic properties of substrate and conductors used, and on the frequency. Since this is a “mixed” dielectric system, the TEM mode can not be supported [2] and the second portion of the investigation was devoted to the effect of variation of length and frequency on the RF performance of the line. Although many papers are available on this topic, but the issues described in this paper have somewhat different point of view.

Mots clés

  • RF MEMS
  • TEM mode
  • HRS
  • TFMLs
Accès libre

Development and Characterization of Surface Micro-Machined MEMS Based Varactor

Publié en ligne: 13 Dec 2017
Pages: 94 - 107

Résumé

Abstract

This paper presents complete behavioral analysis of a surface micro-machined MEMS varactor for frequency tuning application in voltage controlled oscillators in RF applications with high Quality factor and tunability. The dimensions of the MEMS device have been optimized with Finite Element Method based CoventorWare analysis and verified through lumped parameter analysis in Saber platform. The MEMS varactor has been fabricated with the PolyMUMPs process. The paper also describes the Mechanical and electrical characterization of the MEMS varactor to meet the designed specification.

Mots clés

  • MEMS
  • varactor
  • VCO
  • capacitance tuning ratio
  • pull-in
  • SEM
  • vibration spectrum
  • LDV
Accès libre

Fiber Bragg Grating Sensors: New Ideas on Straintemperature Discrimination

Publié en ligne: 13 Dec 2017
Pages: 108 - 117

Résumé

Abstract

In this paper, two novel methods are discussed, wherein Fiber Bragg Gratings are used as sensors to discriminate strain and temperature, simultaneously. These methods provide a good linear response and involve simple fabrication & implementation of the sensors.

Mots clés

  • Fiber Bragg grating sensors
  • strain sensor
  • temperature sensor
  • strain and temperature discrimination
Accès libre

Microstructuring of SU-8 Resist for MEMS and Bio-Applications

Publié en ligne: 13 Dec 2017
Pages: 118 - 129

Résumé

Abstract

Some studies on the fabrication of micro-needles, micro-pillers, and micro-channels using SU-8 negative photoresist for MEMS and bio-applications are reported. The SU-8 processing technology was standardized for the purpose. Micro-pillars were fabricated on SU-8 polymer by soft lithographic technique. Micro-needles were realized on SU-8 film utilizing lensing effect of the etched groove structure of the glass substrate. Micro-channel was fabricated by molding of PDMS polymer on patterned SU-8 ridge structure. Structural characterization of the fabricated structures were investigated using optical microscope and SEM.

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