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Journal Cover Sensors and Actuators A: Physical
  [SJR: 0.902]   [H-I: 116]   [138 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0924-4247
   Published by Elsevier Homepage  [3089 journals]
  • Multiphysics model investigating performance of a micromachined floating
           element shear stress sensor
    • Authors: Nikolas Kastor; Zhengxin Zhao; Robert D. White
      Pages: 1 - 13
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Nikolas Kastor, Zhengxin Zhao, Robert D. White
      A MEMS floating element shear stress sensor has been developed for flow testing applications, targeted primarily at ground and flight testing of aerospace vehicles and components. A comprehensive numerical model of this sensor is described in this paper, quantifying the behavior of the mechanical components, fluid interaction, and electrostatics in three, non-coupled, 3-D numerical simulations: 1) A finite element model of the static element. 2) A steady state, incompressible, viscous, laminar, Newtonian computational fluid dynamics (CFD) model, for both flat and textured versions of the floating shuttle. 3) A finite element model of the capacitive sensing combs. The distribution of aerodynamic forces over the floating element was studied to determine which features contributed most to the total applied force and sensitivity. Shear stress forces account for 74% of the sensitivity of the flat sensor, with the remainder coming primarily from pressure gradient effects. For a textured sensing element, while the total sensor sensitivity increases between 17% and 27%, only 34% of the output is due to shear forces, and the response is more nonlinear. Thus, a flat sensor with as little surface topology as possible is preferable to reduce pressure gradient sensitivity and nonlinearity, even though it may exhibit lower overall sensitivity to flow forces. In addition, the sensor is shown to not only deflect in the direction of flow due to shear forces, but also to lift away from the substrate and pitch its downstream edge away from the surface. Pitch rotation contributes as much as 37% of the output of the sensor for a textured element, but less than 1% for the flat element. For a perfectly symmetric device, differential measurement completely eliminates the contribution from lift. Overall, the model gives a more complete picture of the sensing mechanisms present in a floating element shear stress sensor, and demonstrates the aerodynamic complexities which motivate careful design and calibration of these types of sensors.

      PubDate: 2017-11-10T00:10:37Z
      DOI: 10.1016/j.sna.2017.11.004
      Issue No: Vol. 269 (2017)
       
  • IQ signal based RFID sensors for defect detection and characterisation
    • Authors: Aobo Zhao; Gui Yun Tian; Jun Zhang
      Pages: 14 - 21
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Aobo Zhao, Gui Yun Tian, Jun Zhang
      Radio frequency identification (RFID) sensor systems have unique advantages of identification, communication and sensing together. Previous researches on RFID based sensing investigate power based features, and face the challenges of low sensitivity and robustness due to environment RF field. In this paper, rather than using received signal strength indicator (RSSI), we present a method using features of transient responses from in-phase quadrature (IQ) signal to overcome the challenges of sensitivity and robustness in ultra-high frequency (UHF) RFID sensor systems. The transient responses of the IQ signal are analysed using skewness feature for different defects. The experimental results show that IQ based skewness features from IQ signal improve sensitivity and robustness for defect characterisation compared with previous RSSI and RCS methods.

      PubDate: 2017-11-10T00:10:37Z
      DOI: 10.1016/j.sna.2017.11.008
      Issue No: Vol. 269 (2017)
       
  • Salinity sensor using photonic crystal fiber
    • Authors: D. Vigneswaran; N. Ayyanar; Mohit Sharma; M. Sumathi; Mani Rajan M.S.; K. Porsezian
      Pages: 22 - 28
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): D. Vigneswaran, N. Ayyanar, Mohit Sharma, M. Sumathi, Mani Rajan M.S., K. Porsezian
      A salinity sensor employing photonic crystal fiber is designed for measuring the concentration of salt in sea water. The sea water sample is infiltrated into one of the air holes in cladding, which offers high confinement loss and act as an analyte core mode and background acts as silica mode. In order to satisfy the phase matching condition, the power transferred from silica core to the liquid filled analyte core, which is investigated using finite element method. An enhanced sensitivity of salinity in sea water reports as 5405nm/RIU for x-polarization and 5675nm/RIU for y-polarization with a detection limit of 0.0037 RIU has been reported. The proposed PCF also promises to yield the large birefringence of order 10−3 along with the enhanced sensitivity.

      PubDate: 2017-11-10T00:10:37Z
      DOI: 10.1016/j.sna.2017.10.052
      Issue No: Vol. 269 (2017)
       
  • Wireless chemiluminescence-based sensor for soil deformation detection
    • Authors: K.S.C. Kuang
      Pages: 70 - 78
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): K.S.C. Kuang
      A novel sensing application based on chemiluminescence was designed and tested in the laboratory for deformation monitoring in soil. The device, containing the reactants stored in separate chambers, on activation when deformed under load, result in an almost instantaneous production of light which could be readily detected using low-cost optoelectronics. The attractiveness of this concept for deformation monitoring is that the chemiluminescence sensor is completely passive, requiring no power for it to function. In this paper, the effort was focused on demonstrating the sensing capability of the chemiluminescence-based device for detecting soil deformation or movement in the event of a landslide. Laboratory experiments were conducted to demonstrate the proof-of-concept through a prototype of the device fabricated specifically for this study. Wireless transmission capability was also incorporated into the prototype design in view of the potential deployment in the field.

      PubDate: 2017-11-17T00:36:08Z
      DOI: 10.1016/j.sna.2017.11.017
      Issue No: Vol. 269 (2017)
       
  • A temperature-compensated graphene sensor for nitrate monitoring in
           real-time application
    • Authors: Md Eshrat E. Alahi; Anindya Nag; Subhas Chandra Mukhopadhyay; Lucy Burkitt
      Pages: 79 - 90
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Md Eshrat E. Alahi, Anindya Nag, Subhas Chandra Mukhopadhyay, Lucy Burkitt
      Low-cost nitrate-N sensors and smart sensing systems are necessary to develop a distributed network to monitor the quality of water in real time. This paper presents the fabrication process of carbon printed sensors and the advantage of using a graphene sensor to measure the concentration of nitrate-N in water. The sensor was characterized at different temperatures and with different nitrate-N concentrations in water. Electrochemical Impedance Spectroscopy (EIS) was employed to characterize the developed sensors. The calibration standard with the temperature compensation is also explained. UV-Spectrometry was used to validate all the results and the range of concentrations was 1–70ppm. The sensing system has WiFi connectivity to transfer the data to a cloud server to monitor the data in real time. The sensor has shown good performance during measurements and the developed sensing system has very good potential to be a part of a distributed sensing network to monitor the data in real time.

      PubDate: 2017-11-17T00:36:08Z
      DOI: 10.1016/j.sna.2017.11.022
      Issue No: Vol. 269 (2017)
       
  • Micromachined microbeams made from porous silicon for dynamic and static
           mode sensing
    • Authors: Xiao Sun; Giacinta Parish; Adrian Keating
      Pages: 91 - 98
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Xiao Sun, Giacinta Parish, Adrian Keating
      Through a controlled variation of the applied current during porous silicon formation, newly developed processes enable previously unattainable structural integrity of all-mesoporous silicon microelectromechanical systems (MEMS) structures. Such structures are desirable for applications such as sensing where the large surface area and low Young’s modulus of the high porosity layer enable ultra-high sensitivity detection of adsorbed species. In this work, micromachined all-mesoporous silicon microbeams were released, allowing both the dynamic and static sensing modes to be studied using such porous structures. Resonant frequencies (50–250kHz) of released doubly clamped porous silicon microbeams were measured, allowing mechanical properties to be extracted. Static mode sensing of vapour at the 1100ppm level was also performed, with the released porous silicon cantilevers showing a significant 6.5μm (3.7% of a 175μm beam length) and repeatable deflection after exposure.

      PubDate: 2017-11-17T00:36:08Z
      DOI: 10.1016/j.sna.2017.11.003
      Issue No: Vol. 269 (2017)
       
  • A study of the effect of different coplanar dual-coil geometries on the
           performance of mutual inductance
    • Authors: Siansyun Liao; Weichen Li; Shihwei Lin; Kenwei Tang; Chengshiun Liou; Chingfu Tsou
      Pages: 99 - 110
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Siansyun Liao, Weichen Li, Shihwei Lin, Kenwei Tang, Chengshiun Liou, Chingfu Tsou
      This paper studies the sensing performance of different coplanar dual-coil geometries, which affects the phase variation of mutual inductance. Five micro-coil designs, including square, circular and three rounded rectangular types, are proposed in this study. These are fabricated using a simple silicon-based micro-electroplating process. By measuring the phase variation between the excitation and sensing coils, the sensing performance of different coil designs, with the effect of eddy current, are characterized quantitatively. Commercial COMSOL software and Multisim are used to evaluate the equivalent electrical properties for each type of coil under the same specification. Analysis results show that the phase difference is dominated by mutual inductance and coupling capacitance, and the square-like coils produce a smaller phase difference. The experimental results also show that the more it approached a square-type coil, the smaller the phase difference became. Using saline concentrations from 0% to 20%, the positive phase shift for the square-type coil increased as the concentration increased to a maximum value of plus 4°. The opposite is true of circular coils, with a maximum negative phase shift of minus 5.5°. It is revealed that a specific sensing performance is easily realized by changing the coil geometry and its feature size.

      PubDate: 2017-11-17T00:36:08Z
      DOI: 10.1016/j.sna.2017.07.022
      Issue No: Vol. 269 (2017)
       
  • Numerical investigation of the influence of nozzle geometrical parameters
           on thrust of synthetic jet underwater
    • Authors: Lingbo Geng; Zhiqiang Hu; Yang Lin
      Pages: 111 - 125
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Lingbo Geng, Zhiqiang Hu, Yang Lin
      The thrust characteristic and efficiency of synthetic jet underwater is easily affected by the geometrical parameters. In this paper, the influence of nozzle geometrical parameters on the thrust of synthetic jet underwater is investigated through numerical method. The geometrical parameters studied include nozzle diameter and nozzle height. The numerical method is validated using the experiment data. A mathematical model of the thrust is established. This model decomposes the thrust into three parts. By adjusting the weights of these parts, the dynamic characteristic of the thrust can be rebuilt. Using this method, the mechanism behind the thrust variation with nozzle geometrical parameters is analyzed. The variation of the thrust with the nozzle diameter is induced by the increase of the acceleration force and the decrease of the pressure force. When the nozzle diameter is small, the thrust is velocity dominated. While when diameter is large, the thrust is acceleration dominated. The thrust variation with nozzle height has two different patterns. The pressure force dominates the first pattern of thrust variation. And the acceleration force contributes more to the second pattern of thrust variation. The results in this paper can be used for the efficiency oriented optimal design of synthetic jet actuator underwater.

      PubDate: 2017-11-17T00:36:08Z
      DOI: 10.1016/j.sna.2017.11.018
      Issue No: Vol. 269 (2017)
       
  • Evaluation of mechanical properties in medium carbon steel with a point
           mode electromagnetic sensor
    • Authors: Cunfu He; Yan Huang; Xiucheng Liu; Bin Wu
      Pages: 126 - 136
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Cunfu He, Yan Huang, Xiucheng Liu, Bin Wu
      This paper reports the evaluation of mechanical properties of medium carbon steel based on a novel sensor. The novel point mode electromagnetic sensor with compact configuration and concentrated magnetic flux characteristics has attracted wide attention in recent years. The point mode electromagnetic sensor consists of exciting coil, receiving coil and needle permalloy core embedded into the coil. Response surface methodology was adopted to explore the relationships between the structure paramerters of core (contact radius and height of the cone) and magnetic field intensity based on finite element analysis. The analysis results showed that the contact radius and cone height of the core had important influences on magnetic field intensity. The influence of the cone height was lesser than that of the contact radius. Moreover, the mathematic model was verified effectively by testing magnetic field intensity of different cores based on scanning techniques. Mechanical properties experiment results measured by using a novel sensor showed that a linear correlation exists between the values of amplitude for fundamental and the hardness of samples.

      PubDate: 2017-11-17T00:36:08Z
      DOI: 10.1016/j.sna.2017.11.001
      Issue No: Vol. 269 (2017)
       
  • Design and characterization of a monolithic CMOS-MEMS mutually
           injection-locked oscillator for differential resonant sensing
    • Authors: Pierre Prache; Jérôme Juillard; Pietro Maris Ferreira; Núria Barniol; Marti Riverola
      Pages: 160 - 170
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Pierre Prache, Jérôme Juillard, Pietro Maris Ferreira, Núria Barniol, Marti Riverola
      This paper presents a proof of concept of a differential sensor based on the phase-difference of two injection-locked MEMS resonators, strongly coupled through their actuation voltages by a digital mixer. For the first time the feasibility of a fully monolithically co-integrated CMOS-MEMS differential resonant sensor, exploiting the capabilities of the injection-locked synchronization is proved. The principle of the system is first presented, from which optimal design guidelines are derived. The design of the different blocks of the system is then addressed. Our experimental results demonstrate the sensitivity enhancement of the proposed solution, as predicted by theory, and partial thermal drift rejection in a 70°C range. The simulated and experimental results highlight the critical points of the system design, on which the emphasis of this article is placed.

      PubDate: 2017-11-17T00:36:08Z
      DOI: 10.1016/j.sna.2017.11.025
      Issue No: Vol. 269 (2017)
       
  • A V2O5/4H-SiC Schottky diode-based PTAT sensor operating in a wide range
           of bias currents
    • Authors: Sandro Rao; Giovanni Pangallo; Luigi Di Benedetto; Alfredo Rubino; Gian Domenico Licciardo; Francesco G. Della Corte
      Pages: 171 - 174
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Sandro Rao, Giovanni Pangallo, Luigi Di Benedetto, Alfredo Rubino, Gian Domenico Licciardo, Francesco G. Della Corte
      A proportional to absolute temperature sensor (PTAT) based on V2O5/4H-SiC (vanadium pentoxide/4H polytype of silicon carbide) Schottky diodes is presented. The linear dependence on temperature of the voltage difference appearing at the terminals of two constant-current forward-biased diodes has been used for thermal sensing in the wide temperature range from T =147K to 400K which extends down the state-of-the art of more than 80K. The proposed sensor shows a sensitivity of 307μV/K, a good reproducibility and a stable linear output also in case of deviation of the two bias currents from the best operating condition.

      PubDate: 2017-11-17T00:36:08Z
      DOI: 10.1016/j.sna.2017.11.026
      Issue No: Vol. 269 (2017)
       
  • Brettanomyces bruxellensis growth detection using interdigitated
           microelectrode based sensors by means of impedance analysis
    • Authors: I. Tubia; J. Paredes; E. Pérez-Lorenzo; S. Arana
      Pages: 175 - 181
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): I. Tubia, J. Paredes, E. Pérez-Lorenzo, S. Arana
      Brettanomyces bruxellensis is considered one of the most relevant spoilage yeasts in the production of alcoholic beverages, especially for wine and cider. During fermentation and later storage, these yeasts can cause changes in the characteristics of the product, ruining the aroma and taste. The presence of Brettanomyces causes a decrease in the quality of the final products and important economic losses. The current work presents a detection method based on impedance spectroscopy analysis using label-free interdigitated microelectrode (IDE) based sensors for spoilage yeast detection. Different conditions (static and stirring) were tested in Brettanomyces cultures inside reactors in order to evaluate the growth behavior. Our results indicate a faster response and an 8% increase of the relative variation of the impedance under stirring condition due to biofilm formation onto the surface of the sensors. Equivalent circuit analysis also confirmed that the difference was caused by the larger biofilm formation under dynamic conditions. The results suggest that this technology could be applied for the early detection of spoilage yeast in wine and cider industries, providing more efficient methods to achieve a higher quality of the final products.

      PubDate: 2017-11-17T00:36:08Z
      DOI: 10.1016/j.sna.2017.11.009
      Issue No: Vol. 269 (2017)
       
  • Wireless real-time sensing platform using vibrating wire-based
           geotechnical sensor for underground coal mines
    • Authors: P.K. Mishra; Pratik; Manish Kumar; Subhash Kumar; P.K. Mandal
      Pages: 212 - 217
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): P.K. Mishra, Pratik, Manish Kumar, Subhash Kumar, P.K. Mandal
      Continuous, real-time and remote measurement of stress in underground coal mines plays a vital role in the safety of the mines. Vibrating wire-based geotechnical sensors are widely used for stress measurement of strata in underground coal mines. These types of sensors have several advantages over other geotechnical sensors. However, the measurements from these sensors are taken in-situ using conventional readout unit manually till date even in the case of deep underground coal mines where the depth of cover is more than 300m. When sensor site moves to inaccessible places due to dynamic nature of mining, then the measurement is discontinued and instruments become abandoned. Also, sensors connected through wire get disconnected during movement of machinery, roof falls, and other associated hazards. Therefore, there is a need for wireless sensing platform for vibrating wire-based geotechnical sensors which can assess the stress on a real-time basis and obviate the impending mishap associated with the strata failure. Hence, in the present paper, authors have designed a prototype wireless real-time sensing platform for vibrating wire-based geotechnical sensors for continuous, real-time and remote monitoring of strata behavior. The laboratory trial and the field demonstration of the same have been carried out and compared with conventional readout. The results are in agreement.

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.11.036
      Issue No: Vol. 269 (2017)
       
  • A novel sensor to measure the biased pulse magnetic response in steel stay
           cable for the detection of surface and internal flaws
    • Authors: Xiucheng Liu; Junwu Xiao; Bin Wu; Cunfu He
      Pages: 218 - 226
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Xiucheng Liu, Junwu Xiao, Bin Wu, Cunfu He
      A new type of sensor is designed to measure the biased pulse magnetic response in a large-diameter steel stay cable for the assessment of both surface and internal flaws. The sensor deploys two parallel-connected flexible flat coils (FFC) fed with a biased pulse current as the electromagnet for cable magnetization. A tunnel magneto-resistive (TMR) device and two series-connected sensing coils are used to measure the surface magnetic flux leakage (MFL) and the main-flux variation in the defective cable, respectively. A comparative study between the weak and near-saturated magnetization states of a defective cable is performed by finite element simulation tools to investigate the flaw detection ability of both the surface MFL and main-flux measurement methods With the optimized implementation plan and installation locations of the magnetic sensing elements, a prototype of the sensor and a biased pulse current supply is developed for proof-of-concept experiments. The MFL induced by a surface wire notch with the minimal size of 2mm in width and 1mm in depth can be detected by the TMR device with a lift-off distance of 8mm to the notch. To achieve the quantitative evaluation of multiple internal broken wires (MIBW), main-flux measurements are applied to reveal the effect of the MIBW flaws on the estimated magnetic induction intensity of the cable. The approximate linear dependency of the magnetic induction intensity on the loss rate of the cross-section area can be concluded at the rising and falling edges of the pulsed current. The maximum magnetic induction intensity may act as the feature parameter to characterize the extent of the MIBW flaws with the high accuracy. Compared with the traditional yoke magnetizing sensor, the novel sensor utilizing the FFCs improves the detection flexibility and decreases the weight. The application of the biased pulse current not only reduces the power consumption for coil heating during long-term inspection but also allows the sensor to detect both the surface and internal flaws in the cables.

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.11.005
      Issue No: Vol. 269 (2017)
       
  • Experimental verification of a quasi-trapped degenerate mode magnetic
           acoustic resonator
    • Authors: B.J. Gallacher; J.S. Burdess; Z.X. Hu; H.T. Grigg; C. Dale; J. Hedley; C. Fu; J. Spoors; N. O’Meara; N. Keegan
      Pages: 238 - 248
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): B.J. Gallacher, J.S. Burdess, Z.X. Hu, H.T. Grigg, C. Dale, J. Hedley, C. Fu, J. Spoors, N. O’Meara, N. Keegan
      This paper presents an elastic resonator exhibiting modal degeneracy and quasi-energy trapping of the displacement field. Electromagnetic acoustic based coupling is employed to excite a pair of degenerate SH dominated modes in an aluminium plate. A circular mesa is machined symmetrically on the plate for the purpose of localising the displacement field. Numerical modelling of the modal properties are compared with experimental measurements. Mapping of the modeshapes using 3D laser vibrometry shows that displacement field to be highly localised to the region defining the mesa in agreement with the numerical model. The numerical model shows that significant out of plane displacement outside the mesa region is expected due to the propagating SV+P waves of the plate. It is expected that design modification will reduce the out of plane contributions thus improving the energy trapping. The high Q-factor of the degenerate trapped resonator has potential applications as a gyroscopic sensor or mass sensor.

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.11.039
      Issue No: Vol. 269 (2017)
       
  • Development of a plethysmography system for use under microgravity
           conditions
    • Authors: Angelo Taibi; Mirco Andreotti; Gianluigi Cibinetto; Angelo Cotta Ramusino; Giacomo Gadda; Roberto Malaguti; Luciano Milano; Paolo Zamboni
      Pages: 249 - 257
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Angelo Taibi, Mirco Andreotti, Gianluigi Cibinetto, Angelo Cotta Ramusino, Giacomo Gadda, Roberto Malaguti, Luciano Milano, Paolo Zamboni
      We present a novel application of strain-gauge plethysmography that is suitable to detect blood volume variations in the human venous system. The plethysmography system uses capacitive sensors that are electrically connected to a portable electronic unit to record changes of blood volume over time. Such system has been developed within a project that aimed to monitor the cerebral venous return of the astronaut during an experiment on the International Space Station. In this work, we describe the novel solution in which measurement of elongation is directly obtained by charging the sensor capacitance with a constant current. We also report the full characterization of the plethysmography system and an example of the experimental protocol that has been performed in microgravity condition. Remarkably, the system we propose is able to detect cross-sectional area variations of neck veins with enough sensitivity to be useful for studies concerning cardiac oscillations.

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.11.030
      Issue No: Vol. 269 (2017)
       
  • Giant stress-impedance (GSI) sensor for diameter evaluation in cylindrical
           elements
    • Authors: J.J. Beato-López; G. Vargas-Silva; J.I. Pérez-Landazábal; C. Gómez-Polo
      Pages: 269 - 275
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): J.J. Beato-López, G. Vargas-Silva, J.I. Pérez-Landazábal, C. Gómez-Polo
      In this work, a magnetoelastic sensor to detect the micrometer diameter variations of cylindrical elements is analyzed. A nearly zero magnetostrictive amorphous ribbon with nominal composition (Co0.93Fe0.07)75Si12.5B12.5 was selected as sensor nucleus. The sensor, based on Giant Stress-Impedance (GSI), is attached (glued) along the external perimeter of the cylindrical element. Changes in the cylindrical diameter, DM, induce effective tensile stresses, σS, on the ribbon, giving rise to sensitive changes in the high frequency impedance, Z. The sensor response is analyzed in terms of the relationship between the induced strains and the diameter variations, where the effect of geometrical factors (cylinder diameter and sample length) is taken into account. The results indicate that although the maximum GSI ratio depends on the pre-induced bending stresses associated to the cylindrical configuration, the sample length plays the dominant role in the sensor sensitivity. The proposed device enables to monitor the micrometric diameter variation in cylindrical elements, with a maximum strain gauge factor (GF≈−80) for low induced strains.

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.11.040
      Issue No: Vol. 269 (2017)
       
  • Sensing wood decay in standing trees: A review
    • Authors: Chiew Loon Goh; Ruzairi Abdul Rahim; Mohd Hafiz Fazalul Rahiman; Masturah Tunnur Mohamad Talib; Zhen Cong Tee
      Pages: 276 - 282
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Chiew Loon Goh, Ruzairi Abdul Rahim, Mohd Hafiz Fazalul Rahiman, Masturah Tunnur Mohamad Talib, Zhen Cong Tee
      The decay of wood in a standing tree is often the cause of tree failure. However, the accurate measurement of decay and the non-invasive sensing is still in its infancy. A review of the current sensing methods commonly used for decay detection in standing trees is presented. Methods are compared in terms of the fundamental of measurements, hardware implementation, damage caused to tree and the ease of use. Invasive technique with decay detecting devices, such as increment borer, borescope, decay detecting drill, shigometer, fractometer and radiographic meter, and non-invasive technique involving electrical resistance, microwave, nuclear magnetic resonance and acoustic methods are discussed. This review paper aims to help researchers in this field to identify the remaining issues.

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.11.038
      Issue No: Vol. 269 (2017)
       
  • A new sensor for the analysis of jet momentum spatial distribution
    • Authors: Andrea Bottega; Claudio Dongiovanni
      Pages: 283 - 293
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Andrea Bottega, Claudio Dongiovanni
      Momentum flux is the physical property that deeply affects the evolution of jets and sprays. A sensor able to measure the spatial distribution of momentum in micro-jets and automotive diesel sprays has been designed and critically analysed. The idea behind the sensor is that of deriving the momentum flux profile of a jet/spray impinging against a flat surface by reconstructing the impact pressure distribution. The latter is realized from a set of line integrals of the impact pressure distribution along different directions and by applying the Filtered Back Projection algorithm. The performances of the sensor have hence been theoretically compared to those of a sensor that punctually measures the pressure distribution. The proposed sensor proved to be able to capture a higher frequency content of the momentum under investigation. Finally, the sensor has been employed to investigate the momentum flux of an under-expanded supersonic jet and the corresponding expected characteristic patterns of the impact pressure distribution have been obtained.

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.11.041
      Issue No: Vol. 269 (2017)
       
  • Numerical modeling of existing acoustic emission sensor absolute
           calibration approaches
    • Authors: Markus G.R. Sause; Marvin A. Hamstad
      Pages: 294 - 307
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Markus G.R. Sause, Marvin A. Hamstad
      Within recent years, several alternative approaches to acoustic emission sensor calibration have been proposed. As some of these approaches make use of new geometries and materials, the aspect of absolute calibration in the context of these proposals is evaluated in this contribution. Validated numerical methods are applied to compare the expected acoustic emission sensor sensitivity in a variety of material and geometry configurations. The numerical approach uses a coupled structural and piezoelectric formulation in combination with electric circuit modeling. Established routines allow obtaining the sensitivity versus frequency curve as sensor response in electrical voltage per meters displacement. This study is performed for one previously used conical sensor design and one typical disc type sensor design to examine the impact of the investigated approaches for these different sensor dimensions and designs. Specific attention is paid to the influence of the propagation medium material properties, the chosen wave type and the geometry of the propagation medium. For use of plate-like propagation media further aspects, such as thickness, distance and formation of guided wave modes are evaluated. A primary result is that there is a significant influence to be expected for calibration attempts with different wave types for the same material, which can be of particular relevance when using sensor systems with extended aperture, such as common to most of the commercial sensors.

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.11.057
      Issue No: Vol. 269 (2017)
       
  • Towards replacing resistance thermometry with photonic thermometry
    • Authors: Nikolai Klimov; Thomas Purdy; Zeeshan Ahmed
      Pages: 308 - 312
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Nikolai Klimov, Thomas Purdy, Zeeshan Ahmed
      Resistance thermometry provides a time-tested method for taking temperature measurements that has been painstakingly developed over the last century. However, fundamental limits to resistance-based approaches along with a desire to reduce the cost of sensor ownership and increase sensor stability has produced considerable interest in developing photonic temperature sensors. Here we demonstrate that silicon photonic crystal cavity-based thermometers can measure temperature with uncertainities of 175 mK (k = 1), where uncertainties are dominated by ageing effects originating from the hysteresis in the device packaging materials. Our results, a ≈4-fold improvement over recent developments, clearly demonstate the rapid progress of silicon photonic sensors in replacing legacy devices.

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.11.055
      Issue No: Vol. 269 (2017)
       
  • Nafion film temperature/humidity sensing based on optical fiber
           Fabry-Perot interference
    • Authors: Shuangqiang Liu; Yingke Ji; Jun Yang; Weimin Sun; Hanyang Li
      Pages: 313 - 321
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Shuangqiang Liu, Yingke Ji, Jun Yang, Weimin Sun, Hanyang Li
      A simple method based on Capillary action is proposed to fabricate an optical fiber Fabry-Perot sensing probe for temperature and humidity measurement. Nafion film serves as the thermal and humidity sensing material in this optical fiber sensor. The sensor is constructed by manually depositing a drop of Nafion solution in the capillary and inserting a single mode optical fiber into the capillary. For humidity sensing, we use a fiber Bragg grating (FBG) as temperature compensator. The sensitivity, repeatability, and stability of the sensor were evaluated by analyzing the reflection spectra of the interference fringes. The results indicate that Nafion can be used as the sensing phase of an optical fiber temperature and humidity sensor based on the optical fiber Fabry-Perot interference, presenting a sensitivity of 2.71nm/°C and 3.78nm/%RH.

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.11.034
      Issue No: Vol. 269 (2017)
       
  • Strain sensing of beams in flexural vibrations using rotation rate sensors
    • Authors: Z. Zembaty; P. Bobra; P.A. Bońkowski; S. Kokot; J. Kuś
      Pages: 322 - 330
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Z. Zembaty, P. Bobra, P.A. Bońkowski, S. Kokot, J. Kuś
      This study investigated the application of rotation rate sensors to measure flexural vibrations of beams. This new area of the application of rotational sensors can be beneficial for monitoring various structures, particularly civil engineering structures like reinforced concrete beams and frames and masonry structures, which are difficult to assess using vibration-based damage detection techniques. In a small-scale laboratory experiment, Horizon HZ1-100-100 rotation rate sensors were put in the middle of a plexiglass cantilever beam along with four strain gauges. The beam underwent kinematic excitations, during which variations of the rotations and strains are observed simultaneously. Results of the tests are presented in detail and it was concluded that the rotation rate sensors can be effectively used to monitor flexural vibrations of beams, with particular attention to indirect strain monitoring. In addition, a simple test to check the effectiveness of the rotation rate sensors to monitor stiffness drops in localized locations was carried out. The experiments demonstrated that rotation rate sensors have potential to dramatically improve SHM of civil engineering structures and with improved accuracy, these sensors can find wide application in on-line and post-earthquake structural assessment.

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.11.051
      Issue No: Vol. 269 (2017)
       
  • Tuning the selectivity of NH3 gas sensing response using Cu-doped ZnO
           nanostructures
    • Authors: R. Sankar Ganesh; E. Durgadevi; M. Navaneethan; V.L. Patil; S. Ponnusamy; C. Muthamizhchelvan; S. Kawasaki; P.S. Patil; Y. Hayakawa
      Pages: 331 - 341
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): R. Sankar Ganesh, E. Durgadevi, M. Navaneethan, V.L. Patil, S. Ponnusamy, C. Muthamizhchelvan, S. Kawasaki, P.S. Patil, Y. Hayakawa
      Copper-doped ZnO (CZO) nanoflower and nanoellipsoids were synthesized by hydrothermal method. Field emission electron microscopy and transmission electron microscopy revealed that the flower-like morphology of undoped ZnO transformed into nanoellipsoids upon incorporation of copper (Cu) in ZnO. Raman spectra of copper- doped ZnO showed E2L peak shift compared with undoped ZnO nanoflower which indicated enhanced oxygen or zinc vacancy in copper-doped ZnO. Low-temperature ammonia gas sensing properties based on copper-doped ZnO were systematically studied. Cu-doped ZnO (6wt%) showed enhanced selectivity compared with other copper doping (wt%). Furthermore, the Cu-doped ZnO showed an excellent response and recovery time at a low concentration of ammonia (10ppm). Cu-doped ZnO showed better long-term stability and reproducibility towards ammonia gas.
      Graphical abstract image

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.11.042
      Issue No: Vol. 269 (2017)
       
  • Design and test of Geophonino-3D: A low-cost three-component seismic noise
           recorder for the application of the H/V method
    • Authors: Juan Luis Soler-Llorens; Juan José Galiana-Merino; José Juan Giner-Caturla; Pedro Jauregui-Eslava; Sergio Rosa-Cintas; Julio Rosa-Herranz; Boualem Youcef Nassim Benabdeloued
      Pages: 342 - 354
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Juan Luis Soler-Llorens, Juan José Galiana-Merino, José Juan Giner-Caturla, Pedro Jauregui-Eslava, Sergio Rosa-Cintas, Julio Rosa-Herranz, Boualem Youcef Nassim Benabdeloued
      Earthquake effects are strongly related with the properties of the local geology, amplifying the ground motion, especially in soft soils. This amplification is connected with the resonant frequency, which can be estimated applying the horizontal-to-vertical spectral ratio (H/V) method on seismic noise measurements. In this work, a low-cost user-friendly data acquisition system (Geophonino-3D) has been designed for three-component seismic noise recording. The developed system consists of the signal conditioning circuit and the Arduino Due with an SD Shield for data storage. The suitability of the equipment for the application of the H/V method has been first assessed in the laboratory, according to the experimental sensitivity, the internal noise stability and the channel consistency. Subsequently, experimental verification has been carried out by recording seismic noise at eight different sites along the province of Alicante (southeast Spain), with different soil characteristics. The performance of the developed acquisition system has been evaluated in terms of the power spectral density and the H/V peaks by comparison with the results obtained through a commercial seismic recorder. The obtained results show the applicability of the developed acquisition system to record seismic noise and to apply the H/V method. Geophonino-3D is an open source and open hardware system and the price of its components is much lower than any other commercial equipment, which becomes a significant advance especially for small research groups with reduced economic support.

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.11.047
      Issue No: Vol. 269 (2017)
       
  • Vertical growth of MoS2 layers by sputtering method for efficient
           photoelectric application
    • Authors: Hong-Sik Kim; Melvin David Kumar; Joondong Kim; Donggun Lim
      Pages: 355 - 362
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Hong-Sik Kim, Melvin David Kumar, Joondong Kim, Donggun Lim
      The 2D layers of MoS2 were deposited at RT, 200 °C and 400 °C over p-Si substrates using RF sputtering method. When the deposition temperature is increased beyond 200 °C, the MoS2 layers were grown in vertical direction. XRD studies revealed that the prominent peak is shifted from 2θ = 24° to 13.5° and become narrow while increasing the temperature to 400 °C. The average absorption of 53.68% was exhibited by the sample deposited at 400 °C whereas it was reduced to 28.47% for the sample prepared at 200 °C. When the MoS2/p-Si photodetector was exposed to the red color wavelength, the high photocurrent of 130 μA was produced even at zero bias. The response and recovery times were measured as 38.78 μs and 43.07 μs respectively for λ ≈ 455 nm. The detectivity was found to be in the range of 109–1010 Jones. The proposed MoS2 based photodetector is more beneficial in terms of quick transport of photogenerated carriers and fast response. The growth control and large-scale production of 2D materials would induce the enhanced photoelectric performances and practical device applications.

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.11.050
      Issue No: Vol. 269 (2017)
       
  • Low-frequency noise properties of MgZnO nanorod ultraviolet photodetectors
           with and without UV illumination
    • Authors: Sheng-Joue Young; Yi-Hsing Liu
      Pages: 363 - 368
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Sheng-Joue Young, Yi-Hsing Liu
      Low-frequency current noise measurements were performed on Mg-doped ZnO (MZO) nanorod photodetectors (PD), and 1/f noise was observed in both dark and under ultraviolet (UV) illumination. Results show that the average length and diameter of the nanorods were 609 nm and approximately 50nm, respectively. The X-ray diffraction spectrum showed that the Mg-doped ZnO nanorods had a wurtzite hexagonal sturcture. The photoelectric properties of the nanorods were stable under UV illumination. The resulting Mg-doped ZnO nanorods had excellent potential for UV photodetector applications. Mg-doped ZnO nanorod UV photodetectors had a high UV-to-visible ratio and a fast rise/fall time. The dynamic response of the Mg-doped ZnO nanorod photodetector was stable and reproducible with an on/off current contrast ratio of approximately 4×103. The UV-to-visible rejection ratio of the sample was approximately 400 when biased at 1V, and the fabricated UV photodetector was visible-blind with a sharp cutoff at 350nm. The low-frequency noise spectra obtained from the UV photodetector were caused by the 1/f noise. The noise-equivalent power (NEP) and normalized detectivity (D*) of the Mg-doped ZnO nanorod PD were 3.35×10−10 W and 1.49×108 cmHz0.5W−1, respectively. Under UV illumination, the NEP and D* were 1.8×10−6 W and 2.7×106 cmHz0.5W−1, respectively.

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.11.044
      Issue No: Vol. 269 (2017)
       
  • A simple and easy-to-build optoelectronics force sensor based on light
           fork: Design comparison and experimental evaluation
    • Authors: G. Palli; M. Hosseini; C. Melchiorri
      Pages: 369 - 381
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): G. Palli, M. Hosseini, C. Melchiorri
      In this paper, the design and the implementation of a force sensor based on a commercial optoelectronic component called light fork and characterized by the simple construction process is presented. The proposed sensor implementation is designed to measures the force applied by a cable-based actuation by detecting the deformation of a properly designed compliant structure integrated into the actuation module. Despite this, the design method here presented allows to adapt the sensor to a large set of robotic applications, thanks to its simplicity in the construction and low cost. The main advantages of the proposed sensor consist in the use of a very compact commercial optoelectronic component, called light fork, as sensing element. This solution allows a very simple assembly procedure together with a good sensor response in terms of sensitivity, linearity and noise rejection to be achieved using an extremely simple electronics, thereby obtaining in this way a reliable and very cheap sensor that can be easily integrated in actuation modules for robots and can easily adapted to a wide application set. The paper presents the basic sensor working principle and the compliant frame design. An analytic model of the compliant frame deformation is proposed and verified both by finite element analysis and by experimental measures performed on four different sensor specimens manufactured by 3D printing and CNC milling, and the results have been compared. Moreover, the sensor specimens calibration and the experimental validation have been performed both in static and dynamic conditions.

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.04.054
      Issue No: Vol. 269 (2017)
       
  • Integration of glass micropipettes with a 3D printed aligner for
           microfluidic flow cytometer
    • Authors: Abdullah Bayram; Murat Serhatlioglu; Bulend Ortac; Serafettin Demic; Caglar Elbuken; Mustafa Sen; Mehmet Ertugrul Solmaz
      Pages: 382 - 387
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Abdullah Bayram, Murat Serhatlioglu, Bulend Ortac, Serafettin Demic, Caglar Elbuken, Mustafa Sen, Mehmet Ertugrul Solmaz
      In this study, a facile strategy for fabricating a microfluidic flow cytometer using two glass micropipettes with different sizes and a 3D printed millifluidic aligner was presented. Particle confinement was achieved by hydrodynamic focusing using a single sample and sheath flow. Device performance was extracted using the forward and side-scattered optical signals obtained using fiber-coupled laser and photodetectors. The 3-D printing assisted glass capillary microfluidic device is ultra-low-cost, not labor-intensive and takes less than 10 min to fabricate. The present device offers a great alternative to conventional benchtop flow cytometers in terms of optofluidic configuration.

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.11.056
      Issue No: Vol. 269 (2017)
       
  • Synthesis and characterization of wide-scale UV–vis CUT-OFF laser filter
           using methyl violet-6B/PMMA polymeric composite films
    • Authors: I.S. Yahia; Sherif M.A.S. Keshk; S. AlFaify; A.M. El-Naggar; M.M. Abutalib
      Pages: 388 - 393
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): I.S. Yahia, Sherif M.A.S. Keshk, S. AlFaify, A.M. El-Naggar, M.M. Abutalib
      Poly(methyl methacrylate) (PMMA) doped with different weight percent of methyl violet-6B (MV-6B) as polymeric films were prepared by a casting method. Different concentrations of MV-6B can affect both the crystal structure and optical properties of PMMA. The broad hump diffraction peaks present in PMMA at 2θ = 15.27°, 30.60°, and 40.69° are ascribed to amorphous PMMA. During the incorporation of MV-6B dye onto PMMA, the intense peaks of PMMA at the 2θ value of 15.27° and 30.6° became less intense, and d-spacing was changed. The X-ray results confirmed the strong electrostatic interaction of the cationic MV-6B dye with the anionic PMMA polymer. Furthermore, the transmittance of PMMA/MV-6B composites is decreased with the increase of MV-6B dopants concentrations onto the PMMA matrix; this may be attributed to the electrostatic interaction between the PMMA chains and the molecules of methyl violet-6B. MV-6B-doped PMMA possesses three distinct band gaps corresponding to the pure PMMA, and other two band gaps are for the MV-6B /PMMA composite films. PMMA/MV films with 3.333 wt% of MV-6B) showed a large scale CUT-OFF laser filter inside in the range from 190 to 670 nm. Our designed filter is a unique polymeric composite film for optoelectronic and laser applications.
      Graphical abstract image

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.11.048
      Issue No: Vol. 269 (2017)
       
  • Real-time sitting posture correction system based on highly durable and
           washable electronic textile pressure sensors
    • Authors: Minjeong Kim; Hyoungjun Kim; Jinwoo Park; Kwang-Koo Jee; Jung Ah Lim; Min-Chul Park
      Pages: 394 - 400
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Minjeong Kim, Hyoungjun Kim, Jinwoo Park, Kwang-Koo Jee, Jung Ah Lim, Min-Chul Park
      A real-time sitting posture correction system based on highly durable and washable textile pressure sensors was demonstrated. Textile pressure sensors consisted of conducting Ni-Ti alloy fiber with an excellent fatigue resistance and a pressure-sensitive polyurethane elastomer resulted in reliable capacitance change by an applied pressure in a range from 10 to 180 kPa with a sensitivity of 2.39 kPa−1. The sensing performance was 100% maintained even upon repeated sitting action over 1000 times and harsh washing in detergent-solution. By analyzing the pressure detected at the different positions under the hip, thigh, and back, seven types of sitting postures including upright sitting, sitting with one leg crossed, and sitting with both legs lifted were successfully classified. Finally, real-time display on a monitor of the changes in sitting posture was simulated in order to allow the users to recognize and correct their body balance.

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.11.054
      Issue No: Vol. 269 (2017)
       
  • Nanostructured SnO2 integrated conductive fabrics as binder-free electrode
           for neurotransmitter detection
    • Authors: Sekar Madhu; Pandiaraj Manickam; Michelle Pierre; Shekhar Bhansali; Ponpandian Nagamony; Viswanathan Chinnuswamy
      Pages: 401 - 411
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Sekar Madhu, Pandiaraj Manickam, Michelle Pierre, Shekhar Bhansali, Ponpandian Nagamony, Viswanathan Chinnuswamy
      Exploiting metal oxide nanostructured material as a binder-free electrode material is the key in designing novel electrochemical sensing devices. A conductive carbon yarns (CCY) decorated with definite block shaped SnO2 nanosheets have been constructed and used as a label-free detection of dopamine (DA). Hydrothermal process was used to anchor SnO2 nanostructures on to the surface of CCY. The crystallinity, structure, morphology, elemental and the surface area analysis were performed by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, Field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (FE-SEM/EDS) and Brunauer-Emmett-Teller (BET) instruments. Mechanical properties such as tensile strength, elongation and young’s modulus have also been investigated. In its optimal conditions, the sensor demonstrated a detection limit of 53 nM with a wide linear range from 0.01 to 150 μM for the determination of DA. The proposed SnO2/CCY binder free electrode showed high repeatability, reproducibility with outstanding anti-interference ability towards co-existing molecules such as ascorbic acid (AA) and uric acid (UA). The strategy developed in this work can be scalable and may open up a new approach for making binder-free electrocatalytic sensors on wearable platform.
      Graphical abstract image

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.11.046
      Issue No: Vol. 269 (2017)
       
  • Micron scale energy harvesters using multiple piezoelectric polymer layers
    • Authors: Alperen Toprak; Onur Tigli
      Pages: 412 - 418
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Alperen Toprak, Onur Tigli
      This paper presents the design, fabrication, and experimental results of micron scale energy harvesters that utilize piezoelectric polymer polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE). Proposed devices are free-standing thin film cantilevers with multiple PVDF-TrFE and electrode layers. During the design phase, optimal piezoelectric layer thickness for the chosen substrate was calculated as 7.4μm. In order to alleviate the potential fabrication problems, a multilayer approach was adopted instead of coating a single layer. Device dimensions were selected to yield resonance frequencies below 1kHz. Cantilever type piezoelectric energy harvesters with 3 parallel-connected PVDF-TrFE layers were created using standard microfabrication techniques. Energy harvesting performances of the fabricated devices were evaluated using an electrodynamic shaker and an accelerometer to create and observe input vibrations at different amplitudes and frequencies. Measurement results were compared with theoretical calculations and the effect of substrate clamping was discussed. The power output of a (1800μm×2000μm) prototype was measured as 0.1μW when driven with a peak input acceleration of 1.0g at its resonance frequency of 192.5Hz. Half power bandwidth of the same prototype was measured as 2.9Hz. Proposed energy harvesters have relatively low resonance frequencies for their sizes and have the potential to be easily integrated with other microfabricated devices.

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.11.035
      Issue No: Vol. 269 (2017)
       
  • Piezoelectric characteristics of PNN-PZT/Epoxy paint sensor according to
           the poling conditions
    • Authors: Dae-Hyun Han; Lae-Hyong Kang
      Pages: 419 - 426
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Dae-Hyun Han, Lae-Hyong Kang
      This paper deals with piezoelectric characteristics according to the poling condition in order to improve the disadvantage of conventional poling treatment and find optimal poling condition for the paint sensor. The paint sensor is composed with PNN-PZT (Pb(Nb,Ni)O3-Pb(Zr,Ti)O3) powder and epoxy resin by 1:1wt percent (12.2:87.8vol fraction) in order to reduce the cost and weight. The specimen was made up by using steel mold to get a uniform size, and the dimensions of the paint sensor are 20×10×1.0mm3. The poling treatment has been carried out under controlled conditions of the electric field and the poling time, while the poling temperature has been fixed at the room temperature. The output voltage from the paint sensor and the force from the impact hammer were measured by DAQ device (NI, PXI-6259) in order to measure the piezoelectric sensitivity, when the impact hammer hits the paint sensor by using impact device. The piezoelectric sensitivity defined comparing a paint sensor output voltage with impact force and piezoelectric properties by suggested equation for the paint sensor. The analysis of variance was performed to check the main effect and interaction effect on the sensitivity. In conclusion, the poling time affects the sensitivity more than poling electric field. The optimal poling condition of the paint sensor was obtained that the poling time is 30min, and the electric field is 4kV/mm at room temperature in the air.

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.12.005
      Issue No: Vol. 269 (2017)
       
  • NH3 sensing properties of surface modified Ce-doped nanostructured ZnO
           thin films prepared by spray pyrolysis method
    • Authors: M. Rajendra Prasad; M. Haris; M. Sridharan
      Pages: 435 - 443
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): M. Rajendra Prasad, M. Haris, M. Sridharan
      Cerium doped zinc oxide (CeZnO) (0.001–0.004 M) was deposited on the glass substrate using the spray pyrolysis method. We studied the changes in micro-structural, morphological, optical and gas sensing properties of the thin films at different molarity concentrations. X-ray diffraction (XRD) patterns confirms the hexagonal structure and polycrystalline nature. Crystallite size decreases with increase in Ce concentration. The surface morphology completely modified spherical to hexagonal after adding cerium was observed by using a field-emission scanning electron (FE-SEM) . Transmittance and band gap increases with increases in dopant(Ce) concentrations. The 0.003 M CeZnO thin films shows a good response towards room temperature NH3, the response values is found to be 265.12–2040.81 respectively for 5 ppm–25 ppm. Quick response and recovery time is found to be 18 and 12 s at 25 ppm.
      Graphical abstract image

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.11.045
      Issue No: Vol. 269 (2017)
       
  • Design of a miniature force sensor based on photointerrupter for robotic
           hand
    • Authors: Seok Hwan Jeong; Ho Ju Lee; Kyung-Rok Kim; Kyung-Soo Kim
      Pages: 444 - 453
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Seok Hwan Jeong, Ho Ju Lee, Kyung-Rok Kim, Kyung-Soo Kim
      In this paper, we propose a small, low cost force sensor based on a commercially available photointerrupter for use in a tendon-driven robotic hand. The proposed sensor consists of a photointerrupter and an elastic frame and is designed to measure tendon tension. Using the design methodology presented in this paper, the force sensor can be made small enough (4mm×6mm×10mm) to be inserted into a robotic fingertip and made able to measure a large allowable force (approximately 200N) with low non-linearity (1.85%) and low hysteresis (1.19%). Due to the characteristics of the photointerrupter, it is possible to overcome the disadvantages associated with traditional miniature force sensors and to have very high resolution (0.1N) over the entire measurement range (0–200N). To verify feasibility, we performed force feed-back control using a prototype of the sensor. Experimental results show that the proposed sensor has comparable performance to commercial force sensors of similar size and can be manufactured more simply and economically.

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.11.052
      Issue No: Vol. 269 (2017)
       
  • Capacitive detection of single bacterium from drinking water with a
           detailed investigation of electrical flow cytometry
    • Authors: Mustafa Tahsin Guler; Ismail Bilican
      Pages: 454 - 463
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Mustafa Tahsin Guler, Ismail Bilican
      Pathogenic contamination of drinking water is critical in regard to human health. In this study, we investigated the electrical detection of single bacterium from drinking water. A microfluidics chip consisting of polydimethylsiloxane (PDMS) microchannel and gold microelectrodes was fabricated with conventional microfabrication techniques. Electrical characterizations were done with an LCR meter and the measurements were in good agreement with simulation results. The impact of channel and electrode dimensions was studied for the different type and size of particles, using both experimental and simulation techniques. In addition, the effect of excitation signal frequency and solution conductivity was analyzed employing both simulation and experimental methods. Finally, capacitive detection of a single Escherichia coli (E. coli) from drinking water was successfully carried out under optimum parameters and design geometries.

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.12.008
      Issue No: Vol. 269 (2017)
       
  • Fabrication and implementation of printed sensors for taste sensing
           applications
    • Authors: Anindya Nag; Subhas Chandra Mukhopadhyay; Jürgen Kosel
      Pages: 107 - 116
      Abstract: Publication date: Available online 9 November 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Anindya Nag, Subhas Chandra Mukhopadhyay
      This paper presents the design, fabrication, and implementation of low-cost taste sensors. A single-step procedure was performed using commercial polymer films to develop laser-induced graphene which was used as electrodes in sensor patches for taste sensing purposes. The cost of these sensor patches is less than two dollars based on the requirement for low-cost polymer films and Kapton tapes for developing the sensor patches. Five different chemicals corresponding to the five fundamental tastes of sour, sweet, salty, bitter and umami were tested with the developed sensors. The electrical parameters of the circuitry formed between the electrode-electrolyte interfaces during the experimental procedure were obtained by using the complex non-linear least square curve fitting technique by fitting a simulation curve to the Cole-Cole curve obtained from the experimental results. The sensor patches operating on a capacitive principle, exhibited significant differences in terms of their impedimetric responses for the kinetic processes taking place during the experiments, with different concentrations for each chemical. Four different concentrations were tested for each chemical to analyze the performance of the sensor for that particular chemical. A comparison between the responses of the five chemicals for each concentration was done to inspect the differences between their responses. An analysis of the differences in the conductivity response by the sensor patch for the five chemicals at a specific concentration was also done. The sensor patches did not show any hysteresis in their output responses, while obtaining significant repeatability when testing the chemicals with them. The response time of the sensor patches was around two seconds with the recovery time is 10min for the sensor being thoroughly washed and dried in between experiments The obtained experimental results from these sensor patches and their low cost, and easy fabrication process make them promising for their utilization in taste sensing purposes.

      PubDate: 2017-11-10T00:10:37Z
      DOI: 10.1016/j.sna.2017.08.008
      Issue No: Vol. 264 (2017)
       
  • Laser-sculpted hybrid photonic magnetometer with nanoscale
           magnetostrictive interaction
    • Authors: Thomas Allsop; Graham B. Lee; Changle Wang; Ronald Neal; Kyriacos Kalli; Philip Culverhouse; David J. Webb
      Abstract: Publication date: Available online 12 December 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Thomas Allsop, Graham B. Lee, Changle Wang, Ronald Neal, Kyriacos Kalli, Philip Culverhouse, David J. Webb
      We present a new photonic magnetic sensor that can yield information on the spatial angle of rotation of the sensor within a given static magnetic field that based upon an optical fiber platform that has a wavelength-encoded output and a demonstrated sensitivity of 543 pm/mT. This optical fiber magnetic field sensor combines a conventional, UV-laser inscribed long period grating (LPG) with a magnetostrictive material Terfenol-D that coats and fills 50-μm micro-slots running adjacent and parallel to the fiber central axis. The micro-slots are produced using a femtosecond laser and selective chemical etching. A detection limit for a static magnetic field strength of ±50μT is realized in low strength DC magnetic field (below 0.4 mT), this performance approaches the Earth’s magnetic field strength and thus, once optimized, has potential for navigation applications. Our method addresses the major drawback of conventional sensors, namely their inadequate sensitivity to low strength, static magnetic fields and their inability to provide information about the orientation and magnitude.

      PubDate: 2017-12-12T03:00:46Z
      DOI: 10.1016/j.sna.2017.12.021
       
  • Biomimetic tactile sensors and signal processing with spike trains: A
           review
    • Authors: Zhengkun Yilei; Zhang Jan Peters
      Abstract: Publication date: 1 January 2018
      Source:Sensors and Actuators A: Physical, Volume 269
      Author(s): Zhengkun Yi, Yilei Zhang, Jan Peters
      The sense of touch plays a critical role in enabling human beings to interact with the surrounding environments. As robots move from laboratories to domestic environments, they are expected to be endowed with a similar tactile ability to perform complicated tasks such as manipulating objects with arbitrary unknown shapes. In the past decade, tremendous effort and progress have been made to mimic the sense of touch in human beings on robotic systems. Particularly, biomimetic tactile sensors and signal processing with spike trains have gained a growing interest. In this paper, we firstly review human sense of touch as it serves as a reference point in the case of biomimetic tactile sensing. Then, we focus on biomimetic tactile sensing technologies, which are primarily presented in two aspects: emulating the properties of mechanoreceptors using artificial tactile sensors, and biomimetic tactile signal processing with spike trains. Finally, we discuss the problems in current biomimetic tactile sensing techniques and deduce the future directions.

      PubDate: 2017-11-17T00:36:08Z
       
  • Design and control of a novel asymmetrical piezoelectric actuated
           microgripper for micromanipulation
    • Authors: Cunman Liang; Fujun Wang; Beichao Shi; Zhichen Huo; Kaihuan Zhou; Yanling Tian; Dawei Zhang
      Abstract: Publication date: Available online 14 November 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Cunman Liang, Fujun Wang, Beichao Shi, Zhichen Huo, Kaihuan Zhou, Yanling Tian, Dawei Zhang
      Microgripper is an important tool in high precision micromanipulation task, which directly affects the quality and efficiency of micromanipulation. This paper presents the design and control of a novel asymmetrical microgripper driven by a piezoelectric (PZT) actuator. The developed microgripper is designed as an asymmetrical structure with one movable jaw, so it has the advantages of no dense mode and fixed locating datum compared with the symmetrical microgripper with two movable jaws. The main body of microgripper is a compact flexure-based mechanical structure with a three-stage amplification mechanism. Based on the three-stage amplification structure, large-range, robust and parallel grasping operation can be realized. The characteristics analyses of the developed microgripper are carried out by finite element analysis (FEA). A position-force switching control strategy is utilized to regulate the position and grasping force of movable jaw. Discrete-time sliding model (DSM) controller is designed to control the position and grasping force. Experimental studies are conducted and the experiment results show that the microgripper exhibits good performance and high precision grasping operations can be realized through the developed control strategy.

      PubDate: 2017-11-17T00:36:08Z
      DOI: 10.1016/j.sna.2017.11.027
       
  • Development of highly sensitive optical sensor from carbon
           nanotube-alumina nanocomposite free-standing films: CNTs loading
           dependence sensor performance Analysis
    • Authors: Abid; Poonam Sehrawat; S.S. Islam; Payal Gulati; Mohammad Talib; Prabhash Mishra; Manika Khanuja
      Abstract: Publication date: Available online 9 November 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Abid, Poonam Sehrawat, S.S. Islam, Payal Gulati, Mohammad Talib, Prabhash Mishra, Manika Khanuja
      We report a highly sensitive optical sensor based on free-standing thin films derived from multi-walled carbon nanotubes (MWCNTs)-Alumina nanocomposite by Gel-cast technique. The sensing principle involves the change in the resistance/conductance of the fabricated nanocomposite film on interaction with the optical stimulus. The performance of the sensor strongly depends − on loading and dispersion of MWCNTs in Alumina host matrix; wavelength; and power density of the laser beam. The optimized loading of CNTs to achieve maximum sensitivity was 1.5wt%. The sensitivity of the sensor shows linear relationship with power density of the laser beam and found to be highly sensitive in Vis-NIR region. The maximum sensitivity of the sensor is found to be 13.2% at 635nm wavelength, 3.5mW/mm2power density of laser beam and at 1.5wt% MWCNTs loading in Alumina host matrix. At this loading, the response time and recovery times of the sensor are found to be 1.7s and 2.1s respectively. The additional advantage of the present sensor is that it is facile and cost-effective method to fabricate high performance optical sensors.

      PubDate: 2017-11-10T00:10:37Z
      DOI: 10.1016/j.sna.2017.10.062
       
  • A stepping micromotor based on ferrofluid bearing for side-viewing
           microendoscope applications
    • Authors: Sayed Mohammad Hashem Jayhooni; Babak Assadsangabi; Kenichi Takahata
      Abstract: Publication date: Available online 8 November 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Sayed Mohammad Hashem Jayhooni, Babak Assadsangabi, Kenichi Takahata
      This paper reports a catheter-based electromagnetic micro rotary motor targeting at enabling side-viewing microendoscopes designed for the Raman spectroscopic modality. The micromotor uses the magnetic rotor that is levitated with thin ferrofluid layers inside the polymeric tube and electromagnetically driven with the stator coils circumferentially patterned around the tubular substrate. The device with a new miniaturized design is both theoretically and experimentally shown to provide performance benefits over the preceding design, including 4×higher revolution speeds per given power and >95% reduction in temperature rise at low-speed operation. The precision stepping control of fabricated prototypes with angular steps down to 22.5° is demonstrated with an average positioning error as small as <2%. This is achieved with only two stator coils defined on the tube substrate via controlled power distribution to the coils, uniquely enabling fine stepping actuation with a limited number of stator coils that could be integrated within a microendoscope device. The developed micromotor is suitable for application to side-viewing Raman probes that typically require fine circumferential stepping of laser beam.

      PubDate: 2017-11-10T00:10:37Z
      DOI: 10.1016/j.sna.2017.11.020
       
  • Frequency jump and mode transition of an electrostatic self-excited
           resonator under DC voltage
    • Authors: Mingjing Qi; Hongtao Wu; Yunfei Chen; Zhiwei Liu; Zhi Tao; Xiaoyong Zhang; Xiaojun Yan; Liwei Lin
      Abstract: Publication date: Available online 8 November 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Mingjing Qi, Hongtao Wu, Yunfei Chen, Zhiwei Liu, Zhi Tao, Xiaoyong Zhang, Xiaojun Yan, Liwei Lin
      We report a novel electrostatic self-excited resonator that achieves frequency jump and mode transition under DC voltage powering and control. By gradually increasing the DC voltage by 10%, the frequency output can suddenly jump to 5 times of its original value with the oscillation mode transitioning from the first-order to the second-order. Further, by implementing an artificial insect wing on the resonator, we also present a dual-mode flapping-wing actuator with dramatic increases in lift force and power output after a frequency jump. The frequency jump and mode transition due to small voltage variations have great potential in the field of multi-mode propulsion devices for high-mobility micro-robots.

      PubDate: 2017-11-10T00:10:37Z
      DOI: 10.1016/j.sna.2017.11.019
       
  • Interdisciplinary considerations on the design of MEMS actuators from a
           perspective of their optimality
    • Authors: Ivan Plander; Michal Stepanovsky
      Abstract: Publication date: Available online 7 November 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Ivan Plander, Michal Stepanovsky
      Various phenomena are emerging in existing micro-electro-mechanical systems (MEMS). In order to fully exploit the potential of such systems, a synergy of multiple engineering fields should be reached through a careful analysis of the designed system and its optimization. It is common practice that complex multi-physics finite element method (FEM)-based models are created to analyze the system. Nevertheless, without a clear understanding of the occurred phenomena, an optimal design will be hard to attain. In this paper, we demonstrate that only minimal design changes in existing MEMS actuators can potentially lead to noticeable improvements of the system. We present a case study considering an electrostatic rotational parallel-plate actuator under sliding mode control. This type of actuator is one of the most successful commercial examples of this actuator widely applied in MEMS-based optical switches. The results of this paper confirm that the control strategy of the actuator is a substantial part of the system and should be taken into account; specifically, it can affect the parameters of the designed actuator in order to modify the dynamics of the system in a desired way. In our case, this can reduce the amplitude of output chattering or reduce the switching time of the actuator. Moreover, this paper points out various design flaws, namely when synergy between various system requirements was not reached successfully and only a suboptimal solution was discovered.

      PubDate: 2017-11-10T00:10:37Z
      DOI: 10.1016/j.sna.2017.11.007
       
  • In situ antenna diagnostics and characterization system based on RFID and
           Remotely Piloted Aircrafts
    • Authors: Yuri Guillermo; Narciandi Ana Arboleya Arboleya Fernando Las-Heras Silverio Cabanas
      Abstract: Publication date: Available online 7 November 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Yuri Álvarez López, María García Fernández, Guillermo Álvarez Narciandi, Ana Arboleya Arboleya, Fernando Las-Heras Andrés, Silverio García Cortés, Manés Fernández Cabanas
      A cost-effective solution for in situ antenna characterization and diagnostics based on Radio Frequency IDentification technology and Remotely Piloted Aircrafts is presented. The cost-effectiveness of the proposed solution is achieved by replacing the radio frequency equipment on-board the small aircrafts with Radio Frequency IDentification tags, while the Antenna Under Test is connected to a Radio Frequency IDentification reader, thus reducing the weight and complexity of the payload of the aircrafts dedicated to antenna measurement task. Received Signal Strength measurements are geo-referred with centimeter-level accuracy thanks to a Real Time Kinematic system. An iterative phase retrieval technique based on the Sources Reconstruction Method is used to recover an equivalent magnetic currents distribution on the Antenna Under Test aperture plane. The reconstructed currents distribution provides antenna diagnostics information and enables the calculation of the antenna radiation pattern. The presented method has been validated by means of measurements in the UHF band for two different antenna arrays with excellent results.
      Graphical abstract image Highlights

      PubDate: 2017-11-10T00:10:37Z
       
  • Hybrid methods for MEMS gyro signal noise reduction with fast convergence
           rate and small steady-state error
    • Authors: Xiaoting Guo; Changku Sun; Peng Wang; Lu Huang
      Abstract: Publication date: Available online 7 November 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Xiaoting Guo, Changku Sun, Peng Wang, Lu Huang
      In this paper, a hybrid method is proposed for noise reduction in MEMS gyro signal. To ensure rapid response rate and small steady-state error, and by simultaneously considering the motion state complexity of noisy signal especially under dynamic state, denoising scheme is well-designed, which can be divided into three steps: distinguishing different IMFs modes, determining current motion state, and selecting proper denoising method. Two carefully selected indexes divide the IMFs into three parts, noisy IMFs, mixed IMFs and information IMFs, with the mixed IMFs needed further processing. Sample variances based on AMA are used to determine current motion state. Accordingly, soft interval thresholding, soft thresholding, or forward-backward linear prediction is selected to reduce noise components contained in the mixed IMFs. Denoised mixed IMFs and information IMFs constitute final denoised signal. Practical MEMS gyro signal under different motion conditions are employed to validate the effectiveness of the proposed method. Hilbert spectral analysis and Allan variance further verify the proposed method from qualitative and quantitative point of view. Besides, computational time complexity is also analyzed.

      PubDate: 2017-11-10T00:10:37Z
      DOI: 10.1016/j.sna.2017.11.013
       
  • Compact and sensitive Er3+/Yb3+ co-doped YAG single crystal optical fiber
           thermometry based on up-conversion luminescence
    • Authors: Renjie Bao; Lu Yu; Linhua Ye; Xianwei Zhang; Li-Gang Wang
      Abstract: Publication date: Available online 7 November 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Renjie Bao, Lu Yu, Linhua Ye, Xianwei Zhang, Li-Gang Wang
      Compact and sensitive Er3+/Yb3+ co-doped YAG single crystal optical fiber thermometry based on up-conversion (UC) luminescence is presented. The thermal probe is a YAG single crystal fiber with end Er3+/Yb3+ co-doped grown by laser heated pedestal growth method. Excited by a 976nm laser diode, the UC fluorescence intensity ratio (FIR) of the Er3+ ions in two emission bands (2H11/2,4S3/2 → 4I15/2) was investigated in the temperature range from 298K to 723K. The results indicate that the maximum temperature sensitivity is approximately 0.00486K−1 at 577K. Thus, the Er3+/Yb3+ co-doped YAG single crystal fiber has potential application in optical thermometry by the FIR technique. Furthermore, the thermal probe has compact structure and high thermal stability, making it a more convenient and effective optical fiber temperature sensor.

      PubDate: 2017-11-10T00:10:37Z
      DOI: 10.1016/j.sna.2017.11.012
       
  • Characterization of fiber radiation dosimeters with different embedded
           scintillator materials for radiotherapy applications
    • Authors: Yaosheng Hu; Zhuang Qin; Yu Ma; Wenhui Zhao; Weimin Sun; Daxin Zhang; Ziyin Chen; Boran Wang; He Tian; Elfed Lewis
      Abstract: Publication date: Available online 7 November 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Yaosheng Hu, Zhuang Qin, Yu Ma, Wenhui Zhao, Weimin Sun, Daxin Zhang, Ziyin Chen, Boran Wang, He Tian, Elfed Lewis
      In-vivo real-time dose rate measurement has attracted much attention in the tumor-treatment field because of the demand for precise delivery of radiotherapy. An optical fiber based dosimeter is presented, which is fabricated by embedding scintillator materials inside the fiber core. Five micron-scale powder based scintillator materials have been identified and their characteristics are compared in this investigation. The dosimeters have been fabricated separately but with exactly the same production process. Their emission spectra have been measured. Furthermore, an evaluation of the dosimeter’s performance has been made by analyzing the signal intensity emitted from the scintillation material following transmission through a 25m length of plastic optical fiber (POF) to a distal MPPC (multi-pixel photon counter) detector. The excellent linearity of the relationship of the signal intensity and the dose rate has been established and simultaneously measured using an ionization chamber (IC) to ensure efficacy of the results. The dependence of the resulting fluorescence signal on water depth of two materials was also obtained and compared with the IC. The investigation clearly shows that currently Gd2O2S:Tb is the optimum choice of material for the X-ray optical fiber dosimeter.

      PubDate: 2017-11-10T00:10:37Z
      DOI: 10.1016/j.sna.2017.11.014
       
  • Sensing Strain with Ni-Mn-Ga
    • Authors: Anthony Hobza; Charles L. Patrick; Kari Ullakko; Nader Rafla; Paul Lindquist; Peter Müllner
      Abstract: Publication date: Available online 4 November 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Anthony Hobza, Charles L. Patrick, Kari Ullakko, Nader Rafla, Paul Lindquist, Peter Müllner
      Deformation rearranges the crystal lattice in magnetic shape memory alloys, which changes all anisotropic properties of the material. This study investigates leveraging the deformation-induced change of magnetic permeability for a strain measurement technique. A Ni-Mn-Ga single crystal placed inside a doubly wound coil with a primary and a secondary winding was used as a strain sensor. An AC voltage excited the primary coil and the secondary voltage was measured as the sample was strained from 0 to 5.2%. This method varies from other methods that utilize complex magnetic circuits, require high magnetic fields, or other sensing methods such as Hall probes. When the sensor element was tested statically by compressing the element manually against a bias magnetic field perpendicular to the load axis, the voltage output varied from 129.7mV to 164.2mV. The dynamic performance of the sensor was tested by cycling the element between 25 and 100Hz in compression against a bias magnetic field in a displacement controlled magneto-mechanical test system. The bias magnetic field was varied from 0.2 to 0.8T (0.16 to 0.64MA/m) while the cyclic displacement was varied from 0.5 to 4.5% strain. The voltage amplitude of the signal in the secondary coil increased with decreasing tensile strain. The full scale RMS voltage at a 200 mm stroke increased from 53.0mV to 78.4mV as the bias magnetic field decreased from 0.8T to 0.2T. As the element was compressed, there was no difference in the sensor output voltage between the static and dynamic tests. When the element expanded during unloading, the voltage output of the sensor from the static test matched the voltage output during compression. For the dynamic testing, the voltage output of the sensor exhibited a hysteresis from the loading voltage output, the hysteresis increased when the strain rate increased.

      PubDate: 2017-11-10T00:10:37Z
      DOI: 10.1016/j.sna.2017.11.002
       
 
 
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