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papers from the latest issue:
Self-writing smart labels for humidity monitoring
19 November 2013,
09:42:19
Publication date: 1 January
2014
Source:Sensors and Actuators A: Physical, Volume 205
Author(s): Christian Schoo , Meinhard Knoll
Lateral anodic oxidation is a recent display technique with potential usage in self-writing smart labels and switching applications, which have the ability to operate with established RFID units. This process requires water to operate, which is harvested by a hygroscopic electrolyte layer from the ambient atmosphere. This precondition enables the realization of a humidity monitoring functionality. We develop smart labels displaying the maximum relative humidity during a period of time by the usage of halides providing different hygroscopicity in the electrolyte layer. Therefore we investigate the behavior of the humidity monitoring smart labels under test conditions with diverse relative humidity.
Source:Sensors and Actuators A: Physical, Volume 205
Author(s): Christian Schoo , Meinhard Knoll
Lateral anodic oxidation is a recent display technique with potential usage in self-writing smart labels and switching applications, which have the ability to operate with established RFID units. This process requires water to operate, which is harvested by a hygroscopic electrolyte layer from the ambient atmosphere. This precondition enables the realization of a humidity monitoring functionality. We develop smart labels displaying the maximum relative humidity during a period of time by the usage of halides providing different hygroscopicity in the electrolyte layer. Therefore we investigate the behavior of the humidity monitoring smart labels under test conditions with diverse relative humidity.
Color sensing ability of an amorphous silicon position sensitive detector array system
19 November 2013,
09:42:19
Publication date: 1 January
2014
Source:Sensors and Actuators A: Physical, Volume 205
Author(s): Javier Contreras , Rodrigo Martins , Pawel Wojcik , Sergej Filonovich , Hugo Aguas , Luis Gomes , Elvira Fortunato , Isabel Ferreira
The color sensing ability of a data acquisition prototype system integrating a 32 linear array of 1D amorphous silicon position sensitive detectors (PSD) was analyzed. Besides being used to reproduce a 3D profile of highly reflective surfaces, here we show that it can also differentiate primary red, green, blue (RGB) and derived colors. This was realized by using an incident beam with a RGB color combination and adequate integration times taking into account that a color surface mostly reflects its corresponding color. A mean colorimetric error of 25.7 was obtained. Overall, we show that color detection is possible via the use of this sensor array system, composed by a simpler amorphous silicon pin junction.
Source:Sensors and Actuators A: Physical, Volume 205
Author(s): Javier Contreras , Rodrigo Martins , Pawel Wojcik , Sergej Filonovich , Hugo Aguas , Luis Gomes , Elvira Fortunato , Isabel Ferreira
The color sensing ability of a data acquisition prototype system integrating a 32 linear array of 1D amorphous silicon position sensitive detectors (PSD) was analyzed. Besides being used to reproduce a 3D profile of highly reflective surfaces, here we show that it can also differentiate primary red, green, blue (RGB) and derived colors. This was realized by using an incident beam with a RGB color combination and adequate integration times taking into account that a color surface mostly reflects its corresponding color. A mean colorimetric error of 25.7 was obtained. Overall, we show that color detection is possible via the use of this sensor array system, composed by a simpler amorphous silicon pin junction.
Investigation of guided surface acoustic wave sensors by analytical modeling and perturbation analysis
19 November 2013,
09:42:19
Publication date: 1 January
2014
Source:Sensors and Actuators A: Physical, Volume 205
Author(s): Onursal Onen , Rasim Guldiken
In this paper, shear horizontal polarized guided surface acoustic wave propagation was investigated with analytical modeling and perturbation analysis for biosensing applications. The model was also verified experimentally. The analytical model was developed for multilayer systems taking viscoelasticity into consideration. Detailed parametric investigation of dispersion curves was conducted using various substrate materials and guiding layers. The effects of frequency and degree of viscoelasticity were also studied. Perturbation equations were developed with first order approximations by relating the dispersion curve slopes to sensitivity. Among the guiding layers investigated, Parylene C showed the highest sensitivity followed by gold, chrome and silicon dioxide. The perturbation investigations were also extended to protein layers for immunosensing applications. It was observed that viscous behavior resulted in slightly higher sensitivity, and protein layers showed almost identical sensitivity similar to polymers investigated (SU-8, Parylene, etc.). The optimum configuration is found to be Parylene-C guiding layer on a ST-cut quartz substrate for protein layer sensing and this configuration has 40 times the sensitivity of gold guiding layer on quartz substrate. Our results indicate that chrome and silicon dioxide have low sensitivity when used as guiding layers. Also, lithium tantalate substrate with gold and Parylene-C guiding layers results in ∼10% lower sensitivity as compared to quartz substrate.
Source:Sensors and Actuators A: Physical, Volume 205
Author(s): Onursal Onen , Rasim Guldiken
In this paper, shear horizontal polarized guided surface acoustic wave propagation was investigated with analytical modeling and perturbation analysis for biosensing applications. The model was also verified experimentally. The analytical model was developed for multilayer systems taking viscoelasticity into consideration. Detailed parametric investigation of dispersion curves was conducted using various substrate materials and guiding layers. The effects of frequency and degree of viscoelasticity were also studied. Perturbation equations were developed with first order approximations by relating the dispersion curve slopes to sensitivity. Among the guiding layers investigated, Parylene C showed the highest sensitivity followed by gold, chrome and silicon dioxide. The perturbation investigations were also extended to protein layers for immunosensing applications. It was observed that viscous behavior resulted in slightly higher sensitivity, and protein layers showed almost identical sensitivity similar to polymers investigated (SU-8, Parylene, etc.). The optimum configuration is found to be Parylene-C guiding layer on a ST-cut quartz substrate for protein layer sensing and this configuration has 40 times the sensitivity of gold guiding layer on quartz substrate. Our results indicate that chrome and silicon dioxide have low sensitivity when used as guiding layers. Also, lithium tantalate substrate with gold and Parylene-C guiding layers results in ∼10% lower sensitivity as compared to quartz substrate.
MEMS based normally closed silicon microregulator for gas and water
19 November 2013,
09:42:19
Publication date: 1 January
2014
Source:Sensors and Actuators A: Physical, Volume 205
Author(s): B. Pramanick , S. Das , T.K. Bhattacharyya
This paper presents the design, fabrication and performance evaluation of a normally closed piezoelectrically actuated silicon microregulator. The microregulator is realized using two wafers process and is designed for the maximum operating pressure 5bar and it is found to be leak proof (1×10−4 sccm of helium gas).This paper also reports the development of precision fixturing, assembling and testing of the valve. One of the potential areas for application of microregulators is in satellite propulsion using ion thrusters. Ion thrusters require feed systems with very precise propellant gas flow rate and it makes microregulator a suitable candidate. Another application of the microregulator is liquid propellant flow control in micropropulsion. The water flow measurement of the same microregulator is discussed here. The hysteresis measurement of the silicon membrane using inductive probe and the cyclic test of the microregulator are also described here.
Source:Sensors and Actuators A: Physical, Volume 205
Author(s): B. Pramanick , S. Das , T.K. Bhattacharyya
This paper presents the design, fabrication and performance evaluation of a normally closed piezoelectrically actuated silicon microregulator. The microregulator is realized using two wafers process and is designed for the maximum operating pressure 5bar and it is found to be leak proof (1×10−4 sccm of helium gas).This paper also reports the development of precision fixturing, assembling and testing of the valve. One of the potential areas for application of microregulators is in satellite propulsion using ion thrusters. Ion thrusters require feed systems with very precise propellant gas flow rate and it makes microregulator a suitable candidate. Another application of the microregulator is liquid propellant flow control in micropropulsion. The water flow measurement of the same microregulator is discussed here. The hysteresis measurement of the silicon membrane using inductive probe and the cyclic test of the microregulator are also described here.
A novel compliant micropositioning stage with dual ranges and resolutions
19 November 2013,
09:42:19
Publication date: 1 January
2014
Source:Sensors and Actuators A: Physical, Volume 205
Author(s): Qingsong Xu
Dual-range stages are demanded in precision positioning applications that call for fine resolution in a smaller motion range and coarse resolution in a larger range. Traditional dual-range stages are realized using two actuators, which complicates the mechanism and control design procedures. This paper presents the design and testing of a novel dual-range, dual-resolution precision positioning stage driven by a single linear actuator. The stage structure is devised with leaf flexures to achieve a large stroke. Strain sensors are employed to provide different resolutions in the two motion ranges. To quantify the design of the motion ranges and fine/coarse resolution ratio, analytical models are established and verified through finite element analysis simulations. A proof-of-concept prototype is fabricated for experimental investigations and the experimental results validate the effectiveness of the proposed design. The reported ideas can also be extended to the design of multi-axis micropositioning stages.
Source:Sensors and Actuators A: Physical, Volume 205
Author(s): Qingsong Xu
Dual-range stages are demanded in precision positioning applications that call for fine resolution in a smaller motion range and coarse resolution in a larger range. Traditional dual-range stages are realized using two actuators, which complicates the mechanism and control design procedures. This paper presents the design and testing of a novel dual-range, dual-resolution precision positioning stage driven by a single linear actuator. The stage structure is devised with leaf flexures to achieve a large stroke. Strain sensors are employed to provide different resolutions in the two motion ranges. To quantify the design of the motion ranges and fine/coarse resolution ratio, analytical models are established and verified through finite element analysis simulations. A proof-of-concept prototype is fabricated for experimental investigations and the experimental results validate the effectiveness of the proposed design. The reported ideas can also be extended to the design of multi-axis micropositioning stages.
Design and analysis of a 2D broadband vibration energy harvester for wireless sensors
19 November 2013,
09:42:19
Publication date: 1 January
2014
Source:Sensors and Actuators A: Physical, Volume 205
Author(s): Jin Yang , Xihai Yue , Yumei Wen , Ping Li , Qiangmo Yu , Xiaoling Bai
This paper presents a design for a novel vibration energy harvester using a magnetoelectric (ME) transducer, which is efficiently applicable in two-dimensional (2D) motion and over a range of vibration frequencies. This harvester adopts a circular cross-section cantilever rod to extract the ambient vibration energy because of its ability to host accelerations in arbitrary motion directions. Moreover, the magnetic interactions between the magnets and the ME transducer will lead to the nonlinear oscillation of the rod with increased frequency bandwidth. The influences of the nonlinear vibration factor and magnetic field distribution on the electrical output and bandwidth of the harvester are investigated to achieve optimal vibration energy harvesting performances. The experimental results showed that, the harvester was sensitive to the vibration with arbitrary in-plane directions. With an acceleration of 0.6g (where g =9.8ms−2), it had the working bandwidths of 4.2Hz, 2.6Hz, 2.3Hz, 2.5Hz and 3.2Hz, and the output powers of 0.6mW, 0.49mW, 0.33mW, 0.5mW and 0.56mW at the in-plane excitation angles of−90°, −45°, 0°, 45° and 90°, respectively.
Source:Sensors and Actuators A: Physical, Volume 205
Author(s): Jin Yang , Xihai Yue , Yumei Wen , Ping Li , Qiangmo Yu , Xiaoling Bai
This paper presents a design for a novel vibration energy harvester using a magnetoelectric (ME) transducer, which is efficiently applicable in two-dimensional (2D) motion and over a range of vibration frequencies. This harvester adopts a circular cross-section cantilever rod to extract the ambient vibration energy because of its ability to host accelerations in arbitrary motion directions. Moreover, the magnetic interactions between the magnets and the ME transducer will lead to the nonlinear oscillation of the rod with increased frequency bandwidth. The influences of the nonlinear vibration factor and magnetic field distribution on the electrical output and bandwidth of the harvester are investigated to achieve optimal vibration energy harvesting performances. The experimental results showed that, the harvester was sensitive to the vibration with arbitrary in-plane directions. With an acceleration of 0.6g (where g =9.8ms−2), it had the working bandwidths of 4.2Hz, 2.6Hz, 2.3Hz, 2.5Hz and 3.2Hz, and the output powers of 0.6mW, 0.49mW, 0.33mW, 0.5mW and 0.56mW at the in-plane excitation angles of−90°, −45°, 0°, 45° and 90°, respectively.
Design and evaluation of a skin-like sensor with high stretchability for contact pressure measurement
19 November 2013,
09:42:19
Publication date: 15 December
2013
Source:Sensors and Actuators A: Physical, Volume 204
Author(s): Debao Zhou , Haopeng Wang
This paper presents the development of a new type of skin-like tactile pressure sensor array. The sensor array is scalable, flexible and stretchable and can measure pressure up to 250kPa within 30% stretching rate without damaging its mechanical structure. It can also conform to irregular three-dimensional surfaces. The sensor array consists of three layers. The top and bottom layers are formed by the array of parallel conductive strips made of silver nanowires (AgNWs) embedded in polydimethylsiloxane (PDMS) thin films. The AgNWs/PDMS conductor strips are used as stretchable interconnections to transmit electrical signals. The middle layer is made of PDMS. This film is pre-molded with holes filling with cylinder-shaped conductive elastomer for pressure measurement. In this paper, the characteristic of the AgNWs/PDMS conductor strips as stretchable interconnections is studied. The piezoresistive properties of the sensels (one sensing element is called a sensel) were measured and discussed. The performance of the tactile sensor array under stretching was also tested. With the associated scanning power-supply circuit and data acquisition system, it is demonstrated that the system can successfully capture the tactile images induced by objects of different shapes. Such sensor system could be applied on curved or non-planar surfaces in robots or medical devices for force detection and feedback.
Source:Sensors and Actuators A: Physical, Volume 204
Author(s): Debao Zhou , Haopeng Wang
This paper presents the development of a new type of skin-like tactile pressure sensor array. The sensor array is scalable, flexible and stretchable and can measure pressure up to 250kPa within 30% stretching rate without damaging its mechanical structure. It can also conform to irregular three-dimensional surfaces. The sensor array consists of three layers. The top and bottom layers are formed by the array of parallel conductive strips made of silver nanowires (AgNWs) embedded in polydimethylsiloxane (PDMS) thin films. The AgNWs/PDMS conductor strips are used as stretchable interconnections to transmit electrical signals. The middle layer is made of PDMS. This film is pre-molded with holes filling with cylinder-shaped conductive elastomer for pressure measurement. In this paper, the characteristic of the AgNWs/PDMS conductor strips as stretchable interconnections is studied. The piezoresistive properties of the sensels (one sensing element is called a sensel) were measured and discussed. The performance of the tactile sensor array under stretching was also tested. With the associated scanning power-supply circuit and data acquisition system, it is demonstrated that the system can successfully capture the tactile images induced by objects of different shapes. Such sensor system could be applied on curved or non-planar surfaces in robots or medical devices for force detection and feedback.
Improvement of the off-diagonal magnetoimpedance sensor white noise
19 November 2013,
09:42:19
Publication date: 15 December
2013
Source:Sensors and Actuators A: Physical, Volume 204
Author(s): M. Malatek , B. Dufay , S. Saez , C. Dolabdjian
This work deals with the analysis of noise sources of the off-diagonal magneto-impedance sensor with stress-annealed amorphous ribbon. This experimental analysis shows that the equivalent magnetic noise spectral density is mostly due to the electronic conditioning circuitry that operates the sensor. The electronic noise was then reduced with employment of an improved excitation-detection technique for our sensor and an equivalent magnetic noise spectral density below 1 pT / Hz in white noise region has been reached. Indeed, the equivalent magnetic white noise level of the output signal decreased from 5 pT / Hz to 560 fT / Hz . Nevertheless, this noise level is still limited by the electronic conditioning, leaving room for further improvement.
Source:Sensors and Actuators A: Physical, Volume 204
Author(s): M. Malatek , B. Dufay , S. Saez , C. Dolabdjian
This work deals with the analysis of noise sources of the off-diagonal magneto-impedance sensor with stress-annealed amorphous ribbon. This experimental analysis shows that the equivalent magnetic noise spectral density is mostly due to the electronic conditioning circuitry that operates the sensor. The electronic noise was then reduced with employment of an improved excitation-detection technique for our sensor and an equivalent magnetic noise spectral density below 1 pT / Hz in white noise region has been reached. Indeed, the equivalent magnetic white noise level of the output signal decreased from 5 pT / Hz to 560 fT / Hz . Nevertheless, this noise level is still limited by the electronic conditioning, leaving room for further improvement.
Laser-unzipped carbon nanotube based glucose sensor for separated structure of enzyme modified field effect transistor
19 November 2013,
09:42:19
Publication date: 15 December
2013
Source:Sensors and Actuators A: Physical, Volume 204
Author(s): Wan-Lin Tsai , Yun-Shan Chien , Po-Yu Yang , I-Che Lee , Kuang-Yu Wang , Huang-Chung Cheng
A glucose sensing film composed of unzipped multiwalled carbon nanotubes (MWCNTs) via continuous-wave laser irradiation is investigated. Some structural defects decorate on MWCNTs after an acid treatment, and the MWCNTs are unzipped into sheet-shaped layers initiated from these defects after the laser irradiation. The laser-irradiated carbon nanotube thin films (CNTFs) possess higher conductance owing to larger contact area, and the side edges of unzipped CNTs could act as sensing sites for hydrogen ions. Thus the laser-irradiated CNTF as a glucose sensing film could achieve a higher sensitivity of 0.302mV(mg/dl)−1, equal to 7.55mV(mg/dl)−1 per centimeter square, and a larger linearity of 0.9947 than the as-sprayed one. Moreover, the fully low-temperature processes of this work also reveal the potentials for flexible and disposable biosensors.
Source:Sensors and Actuators A: Physical, Volume 204
Author(s): Wan-Lin Tsai , Yun-Shan Chien , Po-Yu Yang , I-Che Lee , Kuang-Yu Wang , Huang-Chung Cheng
A glucose sensing film composed of unzipped multiwalled carbon nanotubes (MWCNTs) via continuous-wave laser irradiation is investigated. Some structural defects decorate on MWCNTs after an acid treatment, and the MWCNTs are unzipped into sheet-shaped layers initiated from these defects after the laser irradiation. The laser-irradiated carbon nanotube thin films (CNTFs) possess higher conductance owing to larger contact area, and the side edges of unzipped CNTs could act as sensing sites for hydrogen ions. Thus the laser-irradiated CNTF as a glucose sensing film could achieve a higher sensitivity of 0.302mV(mg/dl)−1, equal to 7.55mV(mg/dl)−1 per centimeter square, and a larger linearity of 0.9947 than the as-sprayed one. Moreover, the fully low-temperature processes of this work also reveal the potentials for flexible and disposable biosensors.
Highly enhanced piezoelectric properties of PLZT/PVDF composite by tailoring the ceramic Curie temperature, particle size and volume fraction
19 November 2013,
09:42:19
Publication date: 15 December
2013
Source:Sensors and Actuators A: Physical, Volume 204
Author(s): Peng Han , Shengli Pang , Jingbo Fan , Xiangqian Shen , Tiezheng Pan
Piezoelectric oxides Pb1−x La x (Zr y Ti1−y )1−x/4O3 (PLZT) were synthesized by the solid-state reaction process and Pb0.96La0.04(Zr0.54Ti0.46)0.99O3/polyvinylidene fluoride (PL0.04ZT/PVDF), Pb0.92La0.07(Zr0.555Ti0.445)0.9825O3/PVDF (PL0.07ZT/PVDF) composites with various particle sizes and contents (50–90vol.%) of the ceramic phase were prepared by the hot-press process. The Curie temperature (T c ) of PLZT decreases monotonously from 312°C to 98°C with La content (x) increasing from 0.02 to 0.09. The polarizability of PLZT/PVDF composites increases from 39.5% (PL0.04ZT/PVDF) to 56.7% (PL0.07ZT/PVDF) when poled at 125°C (at the vicinity of T c of PL0.07ZT). As a result, the electrical property improvement with d 33 (ɛ r ) from 53pC/N (159) to 76pC/N (222) proves that tailoring T c of the piezoelectric ceramic to the poling temperature is a useful way to enhance the piezoelectric and dielectric properties of the ceramic/polymer composite. To further investigate the electrical properties of the 0–3 type PLZT/PVDF composite, the particle size and volume fraction of PLZT are also optimized.
Source:Sensors and Actuators A: Physical, Volume 204
Author(s): Peng Han , Shengli Pang , Jingbo Fan , Xiangqian Shen , Tiezheng Pan
Piezoelectric oxides Pb1−x La x (Zr y Ti1−y )1−x/4O3 (PLZT) were synthesized by the solid-state reaction process and Pb0.96La0.04(Zr0.54Ti0.46)0.99O3/polyvinylidene fluoride (PL0.04ZT/PVDF), Pb0.92La0.07(Zr0.555Ti0.445)0.9825O3/PVDF (PL0.07ZT/PVDF) composites with various particle sizes and contents (50–90vol.%) of the ceramic phase were prepared by the hot-press process. The Curie temperature (T c ) of PLZT decreases monotonously from 312°C to 98°C with La content (x) increasing from 0.02 to 0.09. The polarizability of PLZT/PVDF composites increases from 39.5% (PL0.04ZT/PVDF) to 56.7% (PL0.07ZT/PVDF) when poled at 125°C (at the vicinity of T c of PL0.07ZT). As a result, the electrical property improvement with d 33 (ɛ r ) from 53pC/N (159) to 76pC/N (222) proves that tailoring T c of the piezoelectric ceramic to the poling temperature is a useful way to enhance the piezoelectric and dielectric properties of the ceramic/polymer composite. To further investigate the electrical properties of the 0–3 type PLZT/PVDF composite, the particle size and volume fraction of PLZT are also optimized.
Nanometer scale active ground motion isolator
19 November 2013,
09:42:19
Publication date: 15 December
2013
Source:Sensors and Actuators A: Physical, Volume 204
Author(s): R. Le Breton , G. Deleglise , J. Allibe , A. Badel , G. Balik , B. Caron , A. Jeremie , J. Lottin , S. Vilalte
Vibration isolation is a critical issue in various precision engineering fields. A new design of an active isolation system operating heavy loads (up to 50kg) is presented in this work. This system provides state of the art vibration isolation at the nanometer scale for magnets of a future particle accelerator and is more compact than other studies in this field. The choice of sensors and actuators, the mechanical design and the acquisition electronics are investigated in order to reject ground motion efficiently. A dynamic experimental characterization is performed. Based on the identified model, a specific controller, giving an attenuation between 10Hz and 100Hz was designed and experimentally qualified.
Source:Sensors and Actuators A: Physical, Volume 204
Author(s): R. Le Breton , G. Deleglise , J. Allibe , A. Badel , G. Balik , B. Caron , A. Jeremie , J. Lottin , S. Vilalte
Vibration isolation is a critical issue in various precision engineering fields. A new design of an active isolation system operating heavy loads (up to 50kg) is presented in this work. This system provides state of the art vibration isolation at the nanometer scale for magnets of a future particle accelerator and is more compact than other studies in this field. The choice of sensors and actuators, the mechanical design and the acquisition electronics are investigated in order to reject ground motion efficiently. A dynamic experimental characterization is performed. Based on the identified model, a specific controller, giving an attenuation between 10Hz and 100Hz was designed and experimentally qualified.
Development of an auto-calibrated interfacing circuit for thick film multi-gas sensor
19 November 2013,
09:42:19
Publication date: 15 December
2013
Source:Sensors and Actuators A: Physical, Volume 204
Author(s): R. Khakpour , M.N. Hamidon , G.A.E. Vandenbosch
A simple, cheap, and integrated architecture is introduced to measure gases with a thick film gas sensor. The temperatures of the sensors are stabilized by controlling the heaters of the sensors. The heaters’ temperatures are measured by sampling the heaters resistance through the use of a voltage divider and ADCs. A microcontroller accordingly adjusts the output of DACs in order to apply the appropriate steering voltage to the heaters. The method employed to measure the gases is to sample the voltage drop over the resistances of the sensors, which are depending on the gases, by ADCs. The innovation lies in the simplicity of the design and the use of different simple methods and commercially available technologies to fabricate the circuit. Also, a single microcontroller is used to drive and control the heaters’ temperature, to compensate ambient temperature of the heaters, to measure and monitor the amount of gases detected by sensors and finally, to select the sensors. This opens the possibility to use these gas sensors for monitoring purposes at a large scale, for example in alarms and computers.
Source:Sensors and Actuators A: Physical, Volume 204
Author(s): R. Khakpour , M.N. Hamidon , G.A.E. Vandenbosch
A simple, cheap, and integrated architecture is introduced to measure gases with a thick film gas sensor. The temperatures of the sensors are stabilized by controlling the heaters of the sensors. The heaters’ temperatures are measured by sampling the heaters resistance through the use of a voltage divider and ADCs. A microcontroller accordingly adjusts the output of DACs in order to apply the appropriate steering voltage to the heaters. The method employed to measure the gases is to sample the voltage drop over the resistances of the sensors, which are depending on the gases, by ADCs. The innovation lies in the simplicity of the design and the use of different simple methods and commercially available technologies to fabricate the circuit. Also, a single microcontroller is used to drive and control the heaters’ temperature, to compensate ambient temperature of the heaters, to measure and monitor the amount of gases detected by sensors and finally, to select the sensors. This opens the possibility to use these gas sensors for monitoring purposes at a large scale, for example in alarms and computers.
Development of piezoelectric coaxial filament sensors P(VDF-TrFE)/copper for textile structure instrumentation
19 November 2013,
09:42:19
Publication date: 15 December
2013
Source:Sensors and Actuators A: Physical, Volume 204
Author(s): M.B. Kechiche , F. Bauer , O. Harzallah , J.-Y. Drean
Coaxial filaments based on Poly (vinylidene fluoride-co-trifluoroethylene) and copper filament was developed, their mechanical properties characterized. They were then instrumented in textile structure and their detection capabilities were observed. P(VDF-TrFE)/copper coaxial filaments were obtained by a melt spinning process, the mechanical drawing applied at the end of spinning process enabled the increasing of the crystalline β phase from 43% for the copolymer in pellet shape to 52% for the developed coaxial filament of 250μm in diameter. Coaxial filaments surfaces and sections have been analyzed with a scanning electron microscope. The mechanical properties have been quantified by tensile analyses. Coaxial filaments were polarized by the ISL process in order to correlate the level of the polarization with the piezoelectric activity. The textile instrumentation was tested by the integration of some samples in the weft direction of a weaving structure using an industrial weaving machine (Muller NCE 10). An example of electrical signal delivered by integrated filament in textile when subjected to strain and stress actions is shown.
Source:Sensors and Actuators A: Physical, Volume 204
Author(s): M.B. Kechiche , F. Bauer , O. Harzallah , J.-Y. Drean
Coaxial filaments based on Poly (vinylidene fluoride-co-trifluoroethylene) and copper filament was developed, their mechanical properties characterized. They were then instrumented in textile structure and their detection capabilities were observed. P(VDF-TrFE)/copper coaxial filaments were obtained by a melt spinning process, the mechanical drawing applied at the end of spinning process enabled the increasing of the crystalline β phase from 43% for the copolymer in pellet shape to 52% for the developed coaxial filament of 250μm in diameter. Coaxial filaments surfaces and sections have been analyzed with a scanning electron microscope. The mechanical properties have been quantified by tensile analyses. Coaxial filaments were polarized by the ISL process in order to correlate the level of the polarization with the piezoelectric activity. The textile instrumentation was tested by the integration of some samples in the weft direction of a weaving structure using an industrial weaving machine (Muller NCE 10). An example of electrical signal delivered by integrated filament in textile when subjected to strain and stress actions is shown.
A multi-frequency vibration-based MEMS electromagnetic energy harvesting device
19 November 2013,
09:42:19
Publication date: 15 December
2013
Source:Sensors and Actuators A: Physical, Volume 204
Author(s): Huicong Liu , You Qian , Chengkuo Lee
A multi-frequency vibration-based MEMS electromagnetic energy harvesting (EH) device has been presented, fabricated and characterized in this paper. It consists of a permanent magnet and a circular suspension structure on a MEMS EH chip. By emulating the magnetic field of a cylinder magnet, the gap distance between the magnet and EH chip is optimized to be zero for achieving larger magnetic flux change and higher output performance. From the experimental results, the vibration energy can be harvested at three excitation frequencies of 840, 1070 and 1490Hz, which corresponds to the out-of-plane (mode I), torsion (mode II/III) and in-plane (mode IV/V) vibrations of the EH device, respectively. The maximum power densities at these three frequencies are 0.157, 0.014 and 0.117μW/cm3, respectively, for a matched load resistance of 626Ω and an input acceleration of 1.0g. The feasibility study results show promising application potentials for harvesting energy from vibrations of multi-frequency.
Source:Sensors and Actuators A: Physical, Volume 204
Author(s): Huicong Liu , You Qian , Chengkuo Lee
A multi-frequency vibration-based MEMS electromagnetic energy harvesting (EH) device has been presented, fabricated and characterized in this paper. It consists of a permanent magnet and a circular suspension structure on a MEMS EH chip. By emulating the magnetic field of a cylinder magnet, the gap distance between the magnet and EH chip is optimized to be zero for achieving larger magnetic flux change and higher output performance. From the experimental results, the vibration energy can be harvested at three excitation frequencies of 840, 1070 and 1490Hz, which corresponds to the out-of-plane (mode I), torsion (mode II/III) and in-plane (mode IV/V) vibrations of the EH device, respectively. The maximum power densities at these three frequencies are 0.157, 0.014 and 0.117μW/cm3, respectively, for a matched load resistance of 626Ω and an input acceleration of 1.0g. The feasibility study results show promising application potentials for harvesting energy from vibrations of multi-frequency.
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