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Journal Cover Sensors and Actuators A: Physical
  [SJR: 0.902]   [H-I: 116]   [133 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0924-4247
   Published by Elsevier Homepage  [3043 journals]
  • A self-powered, visible-blind ultraviolet photodetector based on n-Ga:ZnO
           nanorods/p-GaN heterojunction
    • Authors: Lu Yang; Hai Zhou; Mengni Xue; Zehao Song; Hao Wang
      Pages: 76 - 81
      Abstract: Publication date: 1 November 2017
      Source:Sensors and Actuators A: Physical, Volume 267
      Author(s): Lu Yang, Hai Zhou, Mengni Xue, Zehao Song, Hao Wang
      A self-powered visible-blind ultraviolet (UV) photodetector based on n-Ga:ZnO nanorods (GZO NRs)/p-GaN heterojunction was reported, in which the n-type GZO NRs were prepared by the water bath method. In this study, we found n-GZO NRs/p-GaN heterojunction devices showed better performance than those of n-ZnO NRs/p-GaN heterojunction devices in terms of the ratio I ph /I dark , responsivity and detectivity. Under UV illumination with the light intensity of 1.31mW/cm2, the ratio I ph /I dark for the n-GZO NRs/p-GaN heterojunction was as high as 3.2×105 at zero bias, which is about 75 times greater than that of an un-doped device (only 4.2×103). Also its responsivity reached 0.23A/W which was three times larger than that of n-ZnO NRs/p-GaN (∼0.08A/W). The reason n-GZO NRs/p-GaN heterojunction displayed lager light/dark current ratio, higher responsivity and detectivity, and more reliable self-powered performance at zero bias may be that in GZO NRs, the Ga-doping reduced the defect states in the nanorods, enhanced the conductivity and electron mobility of the ZnO material and benefited the photo-generated carriers transmission.

      PubDate: 2017-10-14T13:02:31Z
      DOI: 10.1016/j.sna.2017.08.007
      Issue No: Vol. 267 (2017)
       
  • Effect of synthesis temperature on the UV sensing properties of
           ZnO-cellulose nanocomposite powder
    • Authors: Karunakar Sahoo; Amrita Biswas; Jhasaketan Nayak
      Pages: 99 - 105
      Abstract: Publication date: 1 November 2017
      Source:Sensors and Actuators A: Physical, Volume 267
      Author(s): Karunakar Sahoo, Amrita Biswas, Jhasaketan Nayak
      Zinc oxide-cellulose nanocomposite powder was synthesized by a simple, low cost and two step chemical method. In this work, ZnO nanorods were grown on the cellulose fibers (powder) surfaces at three different temperatures by aqueous chemical method for the fabrication of UV sensor. A very high UV sensitivity was observed for a typical ZnO-cellulose nanocomposite. The morphology, structure and optical properties of the powder were studied by scanning electron microscopy, X-rays diffraction and diffused reflectance spectroscopy, respectively. The percentage compositions of ZnO and cellulose were estimated using thermogravimetric analysis. The Brunauer–Emmett–Teller (BET) surface areas of the ZnO-cellulose nanocomposites were estimated by nitrogen adsorption desorption process. Ultraviolet sensitivity of the ZnO-cellulose nanocomposite were studied by current-voltage measurement followed by time resolved photocurrent study. Due to illumination with ultraviolet light, the photocurrent for a typical ZnO-cellulose nanocomposite pellet increased from 2.728×10−8 A to 7.788×10−6 A in 15s. Such a significant enhancement in the conductivity due to UV illumination shows that our ZnO-cellulose can be used for fabrication of UV sensors having ultra-high ON to OFF ratio (I UV/I Dark was 285.4).

      PubDate: 2017-10-14T13:02:31Z
      DOI: 10.1016/j.sna.2017.10.001
      Issue No: Vol. 267 (2017)
       
  • Investigation of a novel MEMS orthogonal fluxgate sensor fabricated with
           Co-based amorphous ribbon core
    • Authors: Shaotao Zhi; Zhu Feng; Lei Guo; Chong Lei; Yong Zhou
      Pages: 121 - 126
      Abstract: Publication date: 1 November 2017
      Source:Sensors and Actuators A: Physical, Volume 267
      Author(s): Shaotao Zhi, Zhu Feng, Lei Guo, Chong Lei, Yong Zhou
      In this paper, we present a novel MEMS orthogonal fluxgate sensor fabricated by standard micro fabricated technology. The sensor mainly consists of a three-dimensional solenoid pick-up coil and a meander-shaped Co-based amorphous ribbon core. The experimental results demonstrate that the sensitivity and noise can be optimized by tuning operation conditions with excitation current amplitude and frequency. The fabricated sensor exhibits a maximum sensitivity of 575V/T, a wide linear range of ±480μT, and a perming below 0.8μT for 90mA rms sinusoidal excitation current at 500kHz frequency. The equivalent magnetic noise is 0.20 nT/√Hz at 1Hz, and the RMS noise is 1.09nT in the frequency range of 0.1–10Hz under the same excitation. In comparison with other micro fabricated fluxgates in similar dimensions, this device possesses relatively high sensitivity and low noise spectral density.

      PubDate: 2017-10-14T13:02:31Z
      DOI: 10.1016/j.sna.2017.09.045
      Issue No: Vol. 267 (2017)
       
  • Application of flexible integrated microsensor to internal real-time
           measurement of vanadium redox flow battery
    • Authors: Chi-Yuan Lee; Chong-An Jiang; Chin-Lung Hsieh; Chia-Hung Chen; Kin-Fu Lin; Yun-Min Liu; Yen-Pu Huang
      Pages: 135 - 141
      Abstract: Publication date: 1 November 2017
      Source:Sensors and Actuators A: Physical, Volume 267
      Author(s): Chi-Yuan Lee, Chong-An Jiang, Chin-Lung Hsieh, Chia-Hung Chen, Kin-Fu Lin, Yun-Min Liu, Yen-Pu Huang
      The temperature distribution and vanadium flow rate distribution in the vanadium redox flow battery are the key to its performance. The reaction process in the vanadium redox flow battery is very complex, in the course of power generation, the uniformity and expendability of vanadium liquid distribution will result in nonuniform temperature distribution. Local high temperature will accelerate the ions through the membrane material, the vanadium electrolyte concentration decreases obviously, so that the overall generating efficiency of vanadium redox flow battery is influenced. On the other hand, under the limitation of low flow rate, the waste heat generated by vanadium redox flow battery is unlikely to be carried away by the flow field, so that the internal temperature of vanadium redox flow battery rises. On the contrary, in the condition of high flow rate, the waste heat in the vanadium redox flow battery dissipates rapidly, the temperature is low, the vanadium redox flow battery efficiency is increased slightly, proving that the flow control is also important to the vanadium redox flow battery performance. However, the authentic information inside the vanadium redox flow battery cannot be obtained accurately and instantly by outside, theory and simulation at the present stage. Therefore, according to the requirement for technical application of internal real-time microscopic diagnosis to vanadium redox flow battery, this study proposes using micro-electro-mechanical systems technology to develop a flexible integrated (temperature and flow) microsensor embedded in the vanadium redox flow battery for real-time measurement. The advantages of this technology include: (1) compactness; (2) flexible measurement position and accurate embedding and (3) accurate measurement, high sensitivity and quick response.

      PubDate: 2017-10-14T13:02:31Z
      DOI: 10.1016/j.sna.2017.10.011
      Issue No: Vol. 267 (2017)
       
  • Electrical-detection droplet microfluidic closed-loop control system for
           precise droplet production
    • Authors: Hai Fu; Wen Zeng; Songjing Li; Shuai Yuan
      Pages: 142 - 149
      Abstract: Publication date: 1 November 2017
      Source:Sensors and Actuators A: Physical, Volume 267
      Author(s): Hai Fu, Wen Zeng, Songjing Li, Shuai Yuan
      To precisely control the size of the droplets is quite important for the application of the droplet microfluidic systems. To date, the size of monodisperse droplets is usually measured by the method of image processing for droplet microfluidics, which requires expensive detection devices such as microscope and high-speed camera. In this paper, an electrical-detection droplet microfluidic closed-loop control system is demonstrated, where the flow rates of fluids are controlled by the pressure-driven microfluidic device and the droplet size can be obtained from the method of electrical detection. The mathematical model of the closed-loop control system is established. Compared with the method of image processing, both the measuring efficiency and accuracy of the droplet size are increased significantly by the electrical-detection method, which can improve the dynamic characteristics of the droplet microfluidic closed-loop control system. In particular, a PI controller is integrated into the closed-loop control system to improve the control precision of the droplet size. By varying the flow rates of the fluids, the effects of the droplet production rates on the dynamic characteristics of the closed-loop control system are studied, and the control precision and stability of the system can be obtained from the experimental measurements.

      PubDate: 2017-10-14T13:02:31Z
      DOI: 10.1016/j.sna.2017.09.043
      Issue No: Vol. 267 (2017)
       
  • A polarisation based approach to model the strain dependent permittivity
           of dielectric elastomers
    • Authors: T. Schlögl; S. Leyendecker
      Pages: 156 - 163
      Abstract: Publication date: 1 November 2017
      Source:Sensors and Actuators A: Physical, Volume 267
      Author(s): T. Schlögl, S. Leyendecker
      A wide-spread lumped parameter model describing the electrostatic pressure present in dielectric elastomer actuators is presented by Pelrine et al. in 1998. In Pelrine's model, the electrostatic pressure is affected by the relative permittivity of the material, also known as dielectric constant. However, many researchers found that the dielectric constant of dielectric elastomers is not constant at all, but decreasing with increasing pre-stretch of the material. This holds especially for acrylic materials such as VHB 4910 from 3M. From a physical point of view, polarisation within the dielectric material is responsible for the material's permittivity and in general, polarisation is deformation dependent. In this work, an alternative modelling approach is presented, explaining the stretch dependent electrostatic pressure. It is shown that Pelrine implicitly assumes that the polarisation of the material is linear in the imposed electric field strength. If this assumption is modified to allow for a more general polarisation field that is based on invariants of the electromechanically coupled problem, a new polarisation based lumped parameter model is obtained. It is shown that this new model fits experimental data found in literature quite well.

      PubDate: 2017-10-14T13:02:31Z
      DOI: 10.1016/j.sna.2017.09.048
      Issue No: Vol. 267 (2017)
       
  • 3D piezoresistive silicon microprobes with stacked suspensions for
           tailored mechanical anisotropies
    • Authors: D. Metz; N. Ferreira; A. Dietzel
      Pages: 164 - 176
      Abstract: Publication date: 1 November 2017
      Source:Sensors and Actuators A: Physical, Volume 267
      Author(s): D. Metz, N. Ferreira, A. Dietzel
      Different kinds of piezoresistive microprobes based on silicon have been developed to enable measurement with high accuracies. However, the typical mechanical anisotropy of such systems leads to the slip of the tip, when probing inclined surfaces. Here, a novel microprobe design is presented, which can be tailored to provide a range of anisotropy or even a perfect isotropy. In the first approach, the microprobe is composed of two stacked silicon membranes. In the second approach, a stainless steel suspension in the form of a laser structured foil is stacked on a silicon membrane. Geometrical parameter studies were carried out by mechanical FEM simulations to determine their influence on the stiffnesses in all spatial directions and to predict anisotropies. Microsystems with selected geometries were fabricated and stacking was obtained through selective adhesive transfer and bonding on a wafer level. Prototypes with anisotropies between 3 and 0.4 were characterized confirming the simulations.

      PubDate: 2017-10-14T13:02:31Z
      DOI: 10.1016/j.sna.2017.09.039
      Issue No: Vol. 267 (2017)
       
  • Realisation of plasma synthetic jet array with a novel sequential
           discharge
    • Authors: Haohua Zong; Marios Kotsonis
      Abstract: Publication date: 15 October 2017
      Source:Sensors and Actuators A: Physical, Volume 266
      Author(s): Haohua Zong, Marios Kotsonis


      PubDate: 2017-10-05T01:18:55Z
      DOI: 10.1016/j.sna.2017.09.027
      Issue No: Vol. 266 (2017)
       
  • Nonlocal vibration and pull-in instability analysis of electrostatic
           carbon-nanotube based NEMS devices
    • Authors: S. Bornassi; H. Haddadpour
      Pages: 185 - 196
      Abstract: Publication date: 15 October 2017
      Source:Sensors and Actuators A: Physical, Volume 266
      Author(s): S. Bornassi, H. Haddadpour
      The objective of this paper is to investigate dynamical pull-in behavior of an electrostatic actuated nano-device based on Eringen's nonlocal elasticity theory. The Euler–Bernoulli beam model is used to establish the dynamic equation of motion of the nano-device subjected to both electrostatic and intermolecular forces. The nanobeam is considered with axially immovable ends and the geometrically nonlinearity due to mid-plane stretching is incorporated to the model as well. A new intermolecular attractive force model based on the macroscopic interactions of a circular cross section nanobeam and a flat surface is presented for the carbon nanotube based nano-device. The nonlinear static equation and the linear dynamic equation are treated by the Differential Quadrature Method (DQM) and through a comprehensive survey, the effect of small scale parameter, DC voltage, intermolecular force, residual stress and geometrical nonlinearity on the fundamental natural frequency and pull-in phenomenon are studied. The results are verified with the literature and a good agreement is achieved.

      PubDate: 2017-09-27T13:31:54Z
      DOI: 10.1016/j.sna.2017.08.020
      Issue No: Vol. 266 (2017)
       
  • Electro-mechanical modelling and experimental characterization of a
           high-aspect-ratio electrostatic-capacitive MEMS device
    • Authors: F. Cerini; M. Ferrari; V. Ferrari; A. Russo; M. Azpeitia Urquia; R. Ardito; B. De Masi; R.I.P. Sedmik
      Pages: 219 - 231
      Abstract: Publication date: 15 October 2017
      Source:Sensors and Actuators A: Physical, Volume 266
      Author(s): F. Cerini, M. Ferrari, V. Ferrari, A. Russo, M. Azpeitia Urquia, R. Ardito, B. De Masi, R.I.P. Sedmik
      As the typical surface separations in Micro Electro-Mechanical Systems (MEMS) are reduced to below one micrometer, detailed knowledge of the interaction forces down to this scale is required. In this context, we have developed a dedicated experimental platform to directly investigate electrostatic and physical effects in a high-aspect-ratio electrostatic-capacitive MEMS device based on commercial technology. In the present work, we report on an extensive experimental characterization, focused on the influence of the surface separations, electric surface potentials, and pressure on the static and dynamical behaviour of the device under precisely controlled conditions. For the proper analysis of the bias position and small‑displacement response of the device, we have developed a comprehensive electro‑mechanical model capable of describing the aforementioned effects, and allowing to extract the mechanical and electrical device parameters from the experimental data. Based on the developed model, a strong experimental evidence is found for significant variations in device characteristics upon reduction of surface separation to below one micrometer.

      PubDate: 2017-10-12T11:44:15Z
      DOI: 10.1016/j.sna.2017.07.048
      Issue No: Vol. 266 (2017)
       
  • Evaluation of a liquid crystal based polarization modulator for a space
           mission thermal environment
    • Authors: Manuel Silva-López; Laurent Bastide; René Restrepo; Pilar García Parejo; Alberto Álvarez-Herrero
      Pages: 247 - 257
      Abstract: Publication date: 15 October 2017
      Source:Sensors and Actuators A: Physical, Volume 266
      Author(s): Manuel Silva-López, Laurent Bastide, René Restrepo, Pilar García Parejo, Alberto Álvarez-Herrero
      The Multi Element Telescope for Imaging and Spectroscopy (METIS) is one of the remote sensing instruments to be onboard the future NASA/ESA Solar Orbiter mission. The science nominal mission orbit will take the spacecraft from 0.28 to 0.95 astronomical units from the Sun, setting challenging and variable thermal conditions to its payload. METIS is an inverted-occultation coronagraph that will image the solar corona in the visible and UV wavelength range. In the visible light path a Polarization Modulation Package (PMP) performs a polarimetric analysis of the incoming solar light. This PMP is based on liquid crystal variable retarders (LCVR) and works under a temporal modulation scheme. The LCVRs behavior has a dependence on temperature and, as a consequence, it is critical to guarantee the PMP performance in the mission thermal environment. Key system specifications are the optical quality and the optical retardance homogeneity. Moreover, the thermally induced elastic deformations of the mechanical mounts and the LCVRs shall not produce any performance degradation. A suitable thermal control is hence required to maintain the system within its allowed limits at any time. The PMP shall also be able to reach specific set-points with the power budget allocated. Consequently, and in order to verify the PMP thermal design, we have experimentally reproduced the expected thermal flight environment. Specifically, a thermal-vacuum cycle test campaign is run at the different mission operational conditions. The purpose is both to check the stability of the thermal conditions and to study the optical quality evolution/degradation. Within this test transmitted wavefront measurements and functional verification tests have been carried out. To do that we adapted an optical interrogation scheme, based on a phase shifting interferometric technique, that allows for inspection of the PMP optical aperture. Finally, measurements obtained at non-operational temperature conditions are also shown. These results demonstrate that the device meets the specifications required to perform its operational role in the space mission environment.

      PubDate: 2017-10-05T01:18:55Z
      DOI: 10.1016/j.sna.2017.09.033
      Issue No: Vol. 266 (2017)
       
  • Towards the noise reduction of piezoelectrical-driven synthetic jet
           actuators
    • Authors: Mark Jabbal; Jonne Jeyalingam
      Pages: 273 - 284
      Abstract: Publication date: 15 October 2017
      Source:Sensors and Actuators A: Physical, Volume 266
      Author(s): Mark Jabbal, Jonne Jeyalingam
      This work details an experimental investigation aimed at reducing the noise output of piezoelectrical-driven synthetic jet actuators while minimising peak jet velocity reduction. The study considers double-chamber actuator for anti-phase noise suppression and lobed orifice as a method to enhance jet turbulent mixing to suppress jet noise. The study involved the design, manufacture and bench test of interchangeable actuator hardware. Hot-wire anemometry and microphone recordings were employed to acquire velocity and sound pressure level measurements respectively across a range of excitation frequencies for a fixed diaphragm clamping and input voltage. The data analysis indicated a 26% noise reduction (16dB) from operating a single-chamber, round orifice actuator to a double-chamber, lobed orifice one at the synthetic jet resonant frequency. Results also showed there was a small reduction in peak jet velocity of 7% (∼3m/s) between these two cases based on orifices of the same discharge area. The electrical-to-fluidic power conversion efficiency of the double-chamber actuator was found to be 15% for both orifice types at the resonant frequency; approximately double the efficiency of a single-chamber actuator.

      PubDate: 2017-10-05T01:18:55Z
      DOI: 10.1016/j.sna.2017.09.036
      Issue No: Vol. 266 (2017)
       
  • Transverse resonance orthogonal beam (TROB) mode for broadband underwater
           sound generation
    • Authors: S. Zhang; L.C. Lim; D.H. Lin; Y.X. Xia; S.P. Lim
      Pages: 285 - 293
      Abstract: Publication date: 15 October 2017
      Source:Sensors and Actuators A: Physical, Volume 266
      Author(s): S. Zhang, L.C. Lim, D.H. Lin, Y.X. Xia, S.P. Lim
      New-generation relaxor-based single crystals exhibit excellent transverse piezoelectric properties and extremely high Poisson’s ratio, making possible a drive mode for underwater sound generation, hereafter referred to as the Transverse Resonance Orthogonal Beam (TROB) mode. Unlike conventional transverse width (CTW) mode in which the resonating direction and the acoustic beam direction are identical, in the TROB mode, the active material is set in resonance in half-wavelength mode in one transverse direction and the acoustic beam is generated in the CTW beam direction, the latter being orthogonal to the resonating transverse direction. For direct drive (pistonless) projectors made of [011]-poled PZN-5.5%PT single crystal of ≤62mm3 in volume, the source levels of underwater sound generated via respective TROB and CTW modes are comparable and can be >180dB re 1μPa @ 1m, which can be combined to advantage to form a broad bandwidth underwater projector. Due to low sound velocities in lead-based relaxor single crystals, the lateral dimensions of direct drive projectors utilizing the TROB excitation mode can be kept at or less than λw/2 in the design, λw being wavelength of sound of the design frequency in water. This makes possible the fabrication of broadband projector arrays via the TROB mode.

      PubDate: 2017-10-05T01:18:55Z
      DOI: 10.1016/j.sna.2017.09.034
      Issue No: Vol. 266 (2017)
       
  • Online auto-calibration of triaxial accelerometer with time-variant model
           structures
    • Authors: L. Ye; A. Argha; B.G. Celler; H.T. Nguyen; S.W. Su
      Pages: 294 - 307
      Abstract: Publication date: 15 October 2017
      Source:Sensors and Actuators A: Physical, Volume 266
      Author(s): L. Ye, A. Argha, B.G. Celler, H.T. Nguyen, S.W. Su
      In this paper, an online auto-calibration method for MicroElectroMechanical Systems (MEMS) triaxial accelerometer (TA) is proposed, which can simultaneously identify the time-dependent model structure and its parameters during the changes of the operating environment. Firstly, the model as well as its associated cost function is linearized by a new proposed linearization approach. Then, exploiting an online sparse recursive least square (SPARLS) estimation, the unknown parameters are identified. In particular, the online sparse recursive method is based on an L 1 -norm penalized expectation-maximum (EM) algorithm, which can amend the model automatically by penalizing the insignificant parameters to zero. Furthermore, this method can reduce computational complexity and be implemented in a low-cost Micro-Controller-Unit (MCU). Based on the numerical analysis, it can be concluded that the proposed recursive algorithm can calculate the unknown parameters reliably and accurately for most MEMS triaxial accelerometers available in the market. Additionally, this method is experimentally validated by comparing the output estimations before and after calibration under various scenarios, which further confirms its feasibility and effectiveness for online TA calibration.

      PubDate: 2017-10-05T01:18:55Z
      DOI: 10.1016/j.sna.2017.08.049
      Issue No: Vol. 266 (2017)
       
  • The measurement of small flow
    • Authors: Jan Krejčí; Lucie Ježová; Radka Kučerová; Robert Plička; Štěpán Broža; David Krejčí; Iva Ventrubová
      Pages: 308 - 313
      Abstract: Publication date: 15 October 2017
      Source:Sensors and Actuators A: Physical, Volume 266
      Author(s): Jan Krejčí, Lucie Ježová, Radka Kučerová, Robert Plička, Štěpán Broža, David Krejčí, Iva Ventrubová
      The paper presents an electrochemical flow meter. It is based on a principle of measuring a response to chemical reaction which depends on the flow. The ferro/ferricyanide redox couple has reliable and robust electrochemical kinetics. The reaction consists of transfer of one electron and change of solvation structure without any change of complex structure. If the geometry of electrochemical cell is not changed the output current depends only on the flow through the cell. This device enables measurement of extremely low flows which is important in microsystem hydrodynamic studies. Measured flow limit of detection is 100 pl/min. The flow resolution is better than 1 pl/min. Time resolution of flow is better than 1s. The device was used in study of peristaltic pump and movable piston pump flow. Sensitive measurement of flow and use of Fast Fourier Transform (FFT) has proved that noise generated by pump is periodic and correlates with the flow. The signal after pump pulsation elimination has white noise. The analysis of sensor signals with FFT in systems with peristaltic pumps or movable piston pumps enables to split the signal to periodic component correlating with the flow and non-periodic component correlating with the measured concentration.

      PubDate: 2017-10-05T01:18:55Z
      DOI: 10.1016/j.sna.2017.08.050
      Issue No: Vol. 266 (2017)
       
  • A novel pneumatic soft sensor for measuring contact force and curvature of
           a soft gripper
    • Authors: Hui Yang; Yang Chen; Yao Sun; Lina Hao
      Pages: 318 - 327
      Abstract: Publication date: 15 October 2017
      Source:Sensors and Actuators A: Physical, Volume 266
      Author(s): Hui Yang, Yang Chen, Yao Sun, Lina Hao
      Soft pneumatic grippers always have characteristics of simple structure, good compliance, and natural motion, which make them have a wide range of applications. Nevertheless, there is a significant challenge that sensors used for detecting gripper’s force and deformation are asked for having good deformability and simple structure, and doing not limit gripper’s behavior. Based on the requirements, a novel pneumatic soft sensor (PSS) is designed and manufactured in this paper. It is composed of a sensing body and a pressure sensor. The sensing body is made of silicon rubber, and has a simple structure and fabrication process. Due to the characteristic of silicon rubber, it can be easily embedded into a soft gripper without restricting its behavior. According to the inner pressure of sensing body, PSS can measure contact force and curvature by building relation models of pressure vs. contact force and pressure vs. curvature, and its measurement accuracy is tested by a large of experiments. The results validate the effectiveness and reliability of PSS. Finally, a novel soft pneumatic finger with two air chambers is designed and fabricated. One of air chambers named inflated air chamber is used for actuating the finger, and another is called sensing air chamber with the function of PSS. Each air chamber has a pressure sensor for measuring inner pressure. The sensing air chamber makes the finger have a self-sensing ability, which has been verified by several tests.

      PubDate: 2017-10-05T01:18:55Z
      DOI: 10.1016/j.sna.2017.09.040
      Issue No: Vol. 266 (2017)
       
  • Pyramid microstructure with single walled carbon nanotubes for flexible
           and transparent micro-pressure sensor with ultra-high sensitivity
    • Authors: Zhenlong Huang; Min Gao; Zhuocheng Yan; Taisong Pan; Saeed Ahmed Khan; Yin Zhang; Hulin Zhang; Yuan Lin
      Pages: 345 - 351
      Abstract: Publication date: 15 October 2017
      Source:Sensors and Actuators A: Physical, Volume 266
      Author(s): Zhenlong Huang, Min Gao, Zhuocheng Yan, Taisong Pan, Saeed Ahmed Khan, Yin Zhang, Hulin Zhang, Yuan Lin
      Using a well-designed PDMS pyramid microstructure covered by non-uniform distributed single walled carbon nanotube (SWCNT) networks, a type of micro-pressure sensors with ultra-high sensitivity, transparency and flexibility were demonstrated. The low-conductivity-tip/high-conductivity-body electrical structure leads to an ultra-high sensitivity of 8655.6kPa−1. The ingenious design of the sensor on structure and material allows a very low unloading current (0.88nA), suggesting an extremely low power to drive the device. Moreover, the device has a fast response time (less than 4ms), low pressure detect limit (less than 7.3Pa) and long-term service life (over than 10000 cycles test). All these features make the sensor an ideal candidate for applications in Electronic-skin and health care.
      Graphical abstract image

      PubDate: 2017-10-12T11:44:15Z
      DOI: 10.1016/j.sna.2017.09.054
      Issue No: Vol. 266 (2017)
       
  • Direct-write Graphene Resistors on Aromatic Polyimide for Transparent
           Heating Glass
    • Authors: Dezhi Wu; Lei Deng; Xuecui Mei; Kwok Siong Teh; Weihua Cai; Qiulin Tan; Yang Zhao; Lingyun Wang; Libo Zhao; Guoxi Luo; Daoheng Sun; Liwei Lin
      Abstract: Publication date: Available online 14 October 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Dezhi Wu, Lei Deng, Xuecui Mei, Kwok Siong Teh, Weihua Cai, Qiulin Tan, Yang Zhao, Lingyun Wang, Libo Zhao, Guoxi Luo, Daoheng Sun, Liwei Lin
      This study reports a scalable process for the direct-write graphene resistors via a CO2 laser to irradiate a spin-coated aromatic polyimide (PI) thin film on top of the glass substrate. With the help of an XY stage, the resistor patterns can be controlled and designed as transparent heaters. Material characterizations by using Raman, SEM, TEM, XRD and AFM have been performed to verify the functional structures. The laser power density has been optimized as 7.27 kw/cm2 with the scanning speed of 1.6mm/s to achieve the best resistivity value of ca. 2.833×10−4 Ω·m for the graphene structures. The effects on the scanning speed and the pulse width to the resulting graphene resistor patterns such as line widths have also been investigated for optimized direct-write process. When the scanning speed and the pulse width were set to 1.6mm/s and 357μs respectively, the mean line width was about 120μm. Experimentally, such laser irradiated graphene was demonstrated to be used as electric transparent heating glass, and different line width and gap have great influence on the heating temperature, heat distribution and transmittance. When the line width and gap distance were 120μm and 2mm on a 4×4cm2 cover glass respectively, the heater can produce a temperature of 92°C on the glass substrate in one minute.

      PubDate: 2017-10-14T13:02:31Z
      DOI: 10.1016/j.sna.2017.10.039
       
  • Deaf People Feeling Music Rhythm by Using a Sensing and Actuating Device
    • Authors: Horațiu Florian; Adrian Mocanu; Cristian Vlasin; José Machado; Vítor Carvalho; Filomena Soares; Adina Astilean; Camelia Avram
      Abstract: Publication date: Available online 14 October 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Horațiu Florian, Adrian Mocanu, Cristian Vlasin, José Machado, Vítor Carvalho, Filomena Soares, Adina Astilean, Camelia Avram
      Quality of life of disabled people in developed societies is one of the main issues to be achieved by evolution of technological solutions as well as obtaining low-cost equipment for achievement this purpose. Some equipment has been developed, and presented, and several studies have been performed about this subject. However, most of them present some gaps that are partially solved in this work. This paper describes a systematic approach and a final prototype for helping deaf people to feel music rhythm. The system hardware includes an audio sensor, two microcontrollers and light and vibrotactile outputs for transmitting the feeling of music rhythm. Also, a software interface has been developed. The prototype has been tested in several institutions that take care of deaf people. About 45 persons tested the equipment and the results achieved are encouraging.

      PubDate: 2017-10-14T13:02:31Z
      DOI: 10.1016/j.sna.2017.10.034
       
  • Design and characterization of a mouse trap based on a bistable mechanism
    • Authors: Quoc-Dung Truong; Ngoc-Dang-Khoa Tran; Dung-An Wang
      Abstract: Publication date: Available online 14 October 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Quoc-Dung Truong, Ngoc-Dang-Khoa Tran, Dung-An Wang
      A mouse trap based on a compliant bistable mechanism (BM) is developed in this investigation. The gripping arms of the trap are the addition to the BM. Catch and release operation of the trap are accomplished by snap-through behaviors of the BM. Two stable equilibrium positions of the BM are correspondent to the baiting and gripping configurations of the trap. The proposed mechanism has no movable joints and gains its mobility from the deflection of compliant members. Device complexity is reduced by integration of jaws and gripping arms with the BM. Utilizing the snap-through behavior of the BM, self-closing function for catching mouse is attained without additional locking parts or latches. Therefore, the catch action is autonomous and does not require additional energy input to hold the trapped mouse. Analytical models are developed for design of the device. Prototypes of the mechanism are fabricated by a simple three dimensional printing process. The characteristics of the mechanism are verified by experiments. A “mouse” is caught and released though the linear motion of the BM. The mouse strap can also be used for assembly and disassembly of industrial parts.

      PubDate: 2017-10-14T13:02:31Z
      DOI: 10.1016/j.sna.2017.10.040
       
  • In situ characterization of radiation sensors based on GaN LED structure
           by pulsed capacitance technique and luminescence spectroscopy
    • Authors: E. Gaubas; T. Čeponis; D. Meškauskas; J. Pavlov; A. Žukauskas; V. Kovalevskij; V. Remeikis
      Abstract: Publication date: Available online 10 October 2017
      Source:Sensors and Actuators A: Physical
      Author(s): E. Gaubas, T. Čeponis, D. Meškauskas, J. Pavlov, A. Žukauskas, V. Kovalevskij, V. Remeikis
      We report on variations of the electrical and optical characteristics of commercial GaN blue LEDs, acting as radiation sensors or dosimeters, during 1.6MeV proton irradiation. Transients of the barrier and storage capacitance have been examined simultaneously with proton-excited luminescence. The pulsed capacitance technique was shown to be a useful tool for the control of changes of the effective density of dopants in the LED structure during proton irradiation, due to introduced radiation defects. The minority carrier injection efficiency can be estimated by measuring the charging current transients of the barrier and storage capacitance. The transient current measurements imply rather fast response of the GaN LED hadron radiation sensors. Also, our results show that the intensity and spectral variations of the proton-excited blue luminescence of the LEDs can be used for the estimation of hadron flux and fluence, respectively. This implies that GaN LED-based sensors can be used for the synchronous detection of hadron irradiation by recording the optical and electrical signals.

      PubDate: 2017-10-12T11:44:15Z
      DOI: 10.1016/j.sna.2017.10.025
       
  • The n-Bi2S3/p-PbS heterojunction for room temperature LPG sensors
    • Authors: R.D. Ladhe; P.K. Baviskar; S.M. Pawar; J.H. Kim; B.R. Sankapal
      Abstract: Publication date: Available online 10 October 2017
      Source:Sensors and Actuators A: Physical
      Author(s): R.D. Ladhe, P.K. Baviskar, S.M. Pawar, J.H. Kim, B.R. Sankapal
      Heterojunction between bi-layer structured nanocrystalline films has been developed towards the liquefied petroleum gas (LPG) sensor at room temperature (27°C) without post annealing treatment. These films consists of n-type Bi2S3 layer on fluorine doped tin oxide (FTO) coated glass substrate followed by deposition of p-type PbS layer to form heterojunction. However, simple and versatile successive ionic layer adsorption and reaction (SILAR) technique have been employed at room temperature (27°C) to deposit the films. This technique involves ions as basic building blocks instead of atoms and hence growth rate can be controlled at ionic level. The completion of device was made by use of ohmic contacts using small drop of silver paste over p-PbS layer as a front contact and FTO coated glass substrate as a back contact. The device was kept overnight in order to dry the paste to ensure good contact. The formed heterojunction is porous with high surface area which enables enough space to adsorb and de-adsorb gas molecules easily and shows the gas response of 71% under the exposure of 1000ppm concentration of LPG with 170s and 300s response and recovery time, respectively along with long term stability.

      PubDate: 2017-10-12T11:44:15Z
      DOI: 10.1016/j.sna.2017.10.024
       
  • Two-axis silicon Hall effect magnetometer
    • Authors: Siya Lozanova; Svetoslav Noykov; Chavdar Roumenin
      Abstract: Publication date: Available online 10 October 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Siya Lozanova, Svetoslav Noykov, Chavdar Roumenin
      A novel single-chip sensing device for measurement of two orthogonal magnetic-field components using a common transducer zone and, for the first time, containing four contacts, is presented. On a rectangular n-type silicon substrate, n+-ohmic planar contacts are implemented − two of them are elongated and serve as power supply, and the other two terminals, positioned in the middle of the region between the elongated ones, function as outputs. A proper coupling arrangement is used for obtaining the information about vector components B x (parallel to the supply contacts) and B z (perpendicular to the substrate). Actually, the 2D magnetometer integrates an in-plane sensitivе Hall element and a device with vertical magnetic-field activation. The sensor operation is determined by the direction of the individual parts of the curvilinear current trajectory and the Lorentz force deflection action on them. The 2D vector sensor interface circuitry in hybrid realization comprises three instrumentation amplifiers and a differential amplifier. Simple fabrication technology is applied, containing four masks. The effective spatial resolution volume is high, constituting about 90×60×40μm3. The respective channel-magnetosensitivities without amplification reached: the lateral sensitivity Sx ≈17V/AT and the vertical sensitivity Sz ≈23.3V/AT. The channel cross-talk at induction B ≤1.0T is no more than 3% and the lowest detected induction B min for the two-axis device at supply 3mA over frequency range f ≤100Hz is about 11μT.

      PubDate: 2017-10-12T11:44:15Z
      DOI: 10.1016/j.sna.2017.10.026
       
  • Design and fabrication of high frequency ultrasonic transducer based on
           lead-free Mn-doped (K0.44Na0.56)NbO3 single crystal
    • Authors: Fangyuan Fan; Xiangyong Zhao; Feifei Wang; Qingwen Yue; Huifang Zhou; Haosu Luo; Yanxue Tang; Zhihua Duan; Wangzhou Shi; Bijun Fang
      Abstract: Publication date: Available online 9 October 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Fangyuan Fan, Xiangyong Zhao, Feifei Wang, Qingwen Yue, Huifang Zhou, Haosu Luo, Yanxue Tang, Zhihua Duan, Wangzhou Shi, Bijun Fang
      In this work, a high-frequency lead-free ultrasonic transducer was designed and fabricated based on high-performance (K0.44Na0.56)NbO3-0.5mol%Mn (Mn-KNN) piezoelectric single crystal. The Krimholtz, Leedom, and Mattaei (KLM) equivalent circuit model was utilized to simulate and optimize the pulse-echo response combined with PiezoCAD software. Theoretically a ∼20MHz medical ultrasonic transducer with an optimized bandwidth up to 85.1% was obtained. The experimental results exhibited a center frequency of 20.9MHz with −6dB bandwidth of 65.3%. The excellent acoustic performance makes this lead-free single-crystal transducer potential for practical applications.

      PubDate: 2017-10-12T11:44:15Z
      DOI: 10.1016/j.sna.2017.10.018
       
  • Piezoelectric particle sizer for measuring bed load using a combination of
           resonance vibration modes
    • Authors: Masatoshi Hayashi; Takuya Kikkawa; Daisuke Koyama; Mami Matsukawa
      Abstract: Publication date: Available online 8 October 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Masatoshi Hayashi, Takuya Kikkawa, Daisuke Koyama, Mami Matsukawa
      To predict environmental changes and prevent disasters in rivers it is important to track how the size distributions of sand and stones in the riverbed change over time. In this paper, we used a passive piezoelectric sensor to measure the particle distribution of a simulated bed load. The sensor had a simple, robust structure consisting of a circular aluminum plate and an annular piezoelectric transducer. The detection characteristics were evaluated by measuring the impact of alumina spheres with diameters of 3–8mm in air. When particles hit the sensor, the impact excited a flexural vibration in the circular plate, generating electric power through the piezoelectric effect. The electric output signal exhibited two main frequency peaks, at 16.3 and 66.7kHz, whose amplitude ratio depended on particle size. These two frequencies correspond to the fundamental and third resonance vibration modes. When particles hit the sensor surface sequentially, we could determine their particle sizes from short-term frequency analysis of the observed voltage waveform.

      PubDate: 2017-10-12T11:44:15Z
      DOI: 10.1016/j.sna.2017.09.057
       
  • A compact dosimetric system for MOSFETs based on passive NFC tag and
           smartphone
    • Authors: M.A. Carvajal; P. Escobedo; M. Jiménez-Melguizo; M.S. Martínez-García; F. Martínez-Martí; A. Martínez-Olmos; A.J. Palma
      Abstract: Publication date: Available online 8 October 2017
      Source:Sensors and Actuators A: Physical
      Author(s): M.A. Carvajal, P. Escobedo, M. Jiménez-Melguizo, M.S. Martínez-García, F. Martínez-Martí, A. Martínez-Olmos, A.J. Palma
      In this work we describe and evaluate a dosimetric system based on an NFC (Near Field Communication) tag and a smartphone that uses commercial MOSFETs as radiation sensors. The tag is designed with commercial integrated circuits and the smartphone is the power source of the tag configured as a readout unit, user interface and storage unit. The NFC tag is supplied wirelessly by the smartphone via NFC, using a home-made structure to align the tag coil and smartphone coil in order to achieve a good inductive coupling. In this case, the commercial DMOS transistor ZVP3306 is used as dosimeter in unbiased mode, connected to the tag before and after each irradiation session to perform the sensor reading. An evaluation of the dosimetric system has been carried out irradiating three transistors with photon beam of 6MV up to 20Gy. The average sensitivity found is (4.75±0.15)mV/Gy, which is in good agreement with the results found with our previously developed dosimetric system. Therefore, this miniaturised dosimetric system can be considered as a promising and low cost electronic architecture to be used for dosimetry control in radio-therapy treatments.

      PubDate: 2017-10-12T11:44:15Z
      DOI: 10.1016/j.sna.2017.10.015
       
  • PI/Al2O3 nanocomposite based long lifetime surface dielectric barrier
           discharge plasma actuator
    • Authors: Dong-Liang Bian; Yun Wu; Min Jia; Chang-Bai Long
      Abstract: Publication date: Available online 7 October 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Dong-Liang Bian, Yun Wu, Min Jia, Chang-Bai Long
      Polyimide (PI) based surface dielectric barrier discharge (SDBD) plasma actuators (PAs) have been widely used in the plasma flow control field due to its flexibility and adhesion, while it has a key drawback of a short lifetime due to the degradation under the plasma processing. There is a strong demand of long lifetime SDBD plasma actuator for its application on the wind turbine, aircraft and aero-engine. This paper reports a novel long lifetime SDBD plasma actuator using PI/Al2O3 nanocomposite as a dielectric barrier. A double-layer construction dielectric, including one layer of PI/Al2O3 nanocomposite film and one layer of pure PI, was tested and compared with a conventional PI based actuator. PI/Al2O3 nanocomposite was prepared by dispersing 13wt% Al2O3 particles with its grain diameter 20nm into PI film. Discharge characteristics were measured with a high-voltage probe, current probe and capacitor probe. The performances were evaluated through induced thrust measurement. Then, the surface characteristics were examined using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Experimental results indicate that PI/Al2O3 nanocomposite based actuator consumes higher electrical power and induces higher thrust. The lifetime of PI/Al2O3 nanocomposite based actuator is 4.2 and 2.3 times longer than that of the PI-based actuator at an excitation peak to peak voltage of 8kV and 10kV with a fixed frequency of 6kHz, respectively. FTIR measurement reveals that incorporation of Al2O3 nanoparticles can weaken the absorption sketch intensities. After discharge for 600min, the PI surface is seriously aged with highly dispersed grooves and protrusions, while the PI/Al2O3 nanocomposite surface is covered by an Al2O3 nanoparticles layer. Furthermore, slightly decrease in oxygen-containing groups measured by XPS suggests that this layer can suppress the surface oxidation and protect the matrix from plasma etching.

      PubDate: 2017-10-12T11:44:15Z
      DOI: 10.1016/j.sna.2017.10.008
       
  • Two types of oil modified tips as force sensors to detect adhesion forces
           between oil and membrane surfaces in fluid
    • Authors: Jing Han; Linyan Xu; Shuangbei Qian; Xiaodong Hu; Tong Guo; Sen Wu; Yanan Liu; Zhongyi Jiang
      Abstract: Publication date: Available online 7 October 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Jing Han, Linyan Xu, Shuangbei Qian, Xiaodong Hu, Tong Guo, Sen Wu, Yanan Liu, Zhongyi Jiang
      The surface resistance to oil is very important for filtration efficiency, film cleaning and life span of ultrafiltration membranes. The atomic force microscope (AFM) has provided unprecedented opportunities to study interface interactions. In this paper, the probe with an oil droplet modified was used as a force sensor for evaluating the oil resistance of membrane surfaces. The adhesion forces between two types of modified tips and a serial of membrane surfaces in fluid was detected via force curves. On the one hand, the AFM probe with an oil droplet immobilized directly was used to study the adhesion forces between a series of PVF/F127 membranes and a hexadecane droplet. On the other hand, a tip attached polystyrene (PS) microsphere covered with a layer of oil was employed. It was found that the oil antifouling performance of membranes was improved effectively through blending F127 with PVF. As the F127 additive varied from 0% to 60%, adhesion force detected by the AFM probe with an hexadecane droplet immobilized showed a decreasing tendency from 2.84 nN to 0.73 nN. Meanwhile, the average interaction force detected by the second modified tip decreased from 3.39 nN to 0.54 nN. The measured force behavior was in agreement with experimental observations of contact angle measurement, which indicated that the blend membranes had better antifouling.
      Graphical abstract image

      PubDate: 2017-10-12T11:44:15Z
      DOI: 10.1016/j.sna.2017.10.003
       
  • A review of screen-printed silver/silver chloride (Ag/AgCl) reference
           electrodes potentially suitable for environmental potentiometric sensors
    • Authors: Marios Sophocleous; John K. Atkinson
      Abstract: Publication date: Available online 7 October 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Marios Sophocleous, John K. Atkinson
      The screen-printed (SP), reference electrode (RE) has been shown to be a crucial element of potentiometric sensors but it is also the stumbling block for reliable and accurate SP sensors. The easiest, most common and most environmentally friendly, type of RE is the Silver/Silver Chloride (Ag/AgCl) RE. Unfortunately, until now the only reliable RE of this kind is the conventional, liquid or gel-filled type. However, for most environmental and soil applications the use of the conventional RE is not an option, which raises the demand for a robust, rugged and low-cost version to replace the conventional RE. This paper presents a review of the various attempts to produce reliable, SP, Ag/AgCl REs, and explain why almost all of them never reach the commercialisation stage. The paper provides an overview of the main challenges that need to be overcome, details of the electrode’s construction, an analytical comparison of their performance in terms of chloride susceptibility, cross-sensitivity and lifetime, and their suitability in different applications depending on their performance characteristics.

      PubDate: 2017-10-12T11:44:15Z
      DOI: 10.1016/j.sna.2017.10.013
       
  • Metamaterial-plasmonic absorber for reducing the spectral shift between
           near- and far-field responses in surface-enhanced spectroscopy
           applications
    • Authors: Erdem Aslan; Ekin Aslan; Mustafa Turkmen; Omer Galip Saracoglu
      Abstract: Publication date: Available online 4 October 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Erdem Aslan, Ekin Aslan, Mustafa Turkmen, Omer Galip Saracoglu
      The spectral shift between near- and far-field responses of the plasmonic nanoantennas has negative effects on the performance of surface-enhanced spectroscopy measurements. In order to reduce these effects, we propose use of the plasmonic absorber (PA) concept that promises lower spectral-shift between the near- and far-field responses. In this context, we present the design, characterization and experimental realization of a novel PA structure which utilizes hexagonally arranged nanoantennas operating in the mid-infrared regime. Additionally, we analyze the PA device numerically and experimentally to investigate tunability of resonant modes. To reveal the absorption mechanism, we investigate the near-field distribution maps in addition to the charge and current density distributions. With the aim of comparing the proposed PA device with the conventional particle-based nanoantenna according to the amount of spectral shift between the near- and far-field peaks, we present the near- and far-field spectra of each configuration and show that PA structure exhibits significantly lower spectral-shift. Finally, we present the effect of reduced spectral-shift on the surface-enhanced infrared absorption spectroscopy through the simulations for the detection of the molecular absorption mode of a polymer and compare with the results of particle nanoantenna configuration.

      PubDate: 2017-10-05T01:18:55Z
      DOI: 10.1016/j.sna.2017.10.006
       
  • Mode matching of a laser-beam to a compact high finesse bow-tie optical
           cavity for quartz enhanced photoacoustic gas sensing
    • Authors: Pietro Patimisco; Angelo Sampaolo Frank Tittel Vincenzo Spagnolo
      Abstract: Publication date: Available online 4 October 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Pietro Patimisco, Angelo Sampaolo, Frank K. Tittel, Vincenzo Spagnolo
      We report on the optical characterization of a compact bow-tie cavity composed of two flat mirrors and two concave mirrors, all having a reflectance >99.99% in the spectral range between 4.8μm and 5.3μm, mounted in a stainless-steel enclosure. The cavity was designed for the implementation of an intracavity-quartz enhanced photoacoustic sensor system. The propagation parameters of the intra-cavity beam were determined using the ABCD-matrix method, allowing the analytical formulation of the size of two beam waists occurring inside the cavity. A collimated mid-infrared laser beam was optically coupled and mode matched into the bow-tie cavity via a focusing lens. A cavity finesse of∼2,000 was measured at a pressure of 90Torr inside the cavity, corresponding to an optical power enhancement factor of∼320.

      PubDate: 2017-10-05T01:18:55Z
       
  • An array of physical sensors and an adaptive regression strategy for
           emotion recognition in a noisy scenario
    • Authors: Francesco Mosciano; Arianna Mencattini; Fabien Ringeval; Björn Schuller; Eugenio Martinelli; Corrado Di Natale
      Abstract: Publication date: Available online 2 October 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Francesco Mosciano, Arianna Mencattini, Fabien Ringeval, Björn Schuller, Eugenio Martinelli, Corrado Di Natale
      Several studies demonstrate that since emotions are spontaneously manifested through different measurable quantities (e.g. vocal and facial expressions), this makes possible a sort of automatic estimation of emotion from objective measurements. However, the reliability of such estimations is strongly influenced by the availability of the different sensor modalities used to monitor the affective status of a subject, and furthermore the extraction of objective parameters is sometime thwarted in a noisy and disturbed environment. This paper introduces a personalized emotion estimation based on a heterogeneous array of physical sensors for the measurement of vocal, facial, and physiological (electro-cardiogram and electro-dermal) activities. As a proof of concept, changes in the levels of both emotion reactiveness and pleasantness are estimated under critical operative conditions. The estimator model takes advantage from the time-varying selection of the most relevant non-spurious sensors features and the adaptation of the k-nearest neighbour paradigm to the continuous identification of the most affine model templates. The model, once trained, demonstrated to autonomously embed new sensorial input and adapt to unwanted/unpredicted sensor noise or emotion alteration. The proposed approach has been successfully tested on the RECOLA database, a multi-sensorial corpus of spontaneous emotional interactions in French.

      PubDate: 2017-10-05T01:18:55Z
      DOI: 10.1016/j.sna.2017.09.056
       
  • Comparison between Ir, Ir0.85Rh0.15 and Ir0.7Rh0.3 thin films as
           electrodes for surface acoustic waves applications above 800°C in air
           atmosphere
    • Authors: Amine Taguett; Thierry Aubert; Omar Elmazria; Florian Bartoli; Marc Lomello; Michel Hehn; Jaafar Ghanbaja; Pascal Boulet; Stéphane Mangin; Yong Xu
      Abstract: Publication date: Available online 20 September 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Amine Taguett, Thierry Aubert, Omar Elmazria, Florian Bartoli, Marc Lomello, Michel Hehn, Jaafar Ghanbaja, Pascal Boulet, Stéphane Mangin, Yong Xu
      In this paper, we investigate the suitability of Ir, Ir0.85Rh0.15 and Ir0.7Rh0.3 thin films as electrodes for surface acoustic waves (SAW devices) applications taking place above 800°C in air atmosphere. As expected, all films oxidize from 800°C in IrO2 or IrxRh1-xO2 phase. The electrical properties of the latter remain compatible with the design of SAW devices, with a specific electrical resistance of 151 and 100μΩ·cm for x=0.7 and x=0.85 respectively. Moreover, we observe that the IrxRh1-xO2 phase is much more stable regarding sublimation effect than the IrO2 phase, highlighting the interest of alloying Ir with Rh for high-temperature applications. SAW devices based on langasite substrate and Ir0.85Rh0.15 electrodes show a very good stability for at least several days at 800°C in air. In the case of Ir0.7Rh0.3 electrodes, this stability is extended to temperatures up to 900°C.

      PubDate: 2017-09-20T16:00:13Z
      DOI: 10.1016/j.sna.2017.09.031
       
  • High temperature gradient calorimetric wall shear stress micro-sensor for
           flow separation detection
    • Authors: Ghouila-Houri Quentin; Gallas Eric Garnier Alain Merlen Romain Viard Abdelkrim
      Abstract: Publication date: Available online 19 September 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Cécile Ghouila-Houri, Quentin Gallas, Eric Garnier, Alain Merlen, Romain Viard, Abdelkrim Talbi, Philippe Pernod
      The paper describes and discusses the design and testing of an efficient and high-sensitivity calorimetric thermal sensor developed for bi-directional wall shear stress measurements in aerodynamic flows. The main technical application targeted is flow separation detection. The measurement principle is based on the forced convective heat transfer from a heater element. The sensor structure is composed of three parallel substrate-free wires presenting a high aspect ratio and supported by periodic perpendicular SiO2 micro-bridges. This hybrid structure takes advantages from both conventional hot-films and hot-wires, ensuring near-wall and non-intrusive measurement, mechanical toughness and thermal insulation to the bulk substrate, and it allowed to add the calorimetric sensor functionality to detect simultaneously the wall shear stress amplitude and direction. The central wire is made of a multilayer structure composed of a heater element (Au/Ti) and a thermistor (Ni/Pt/Ni/Pt/Ni) enabling measurement of the heater temperature and a layer of SiO2 between them for electrical insulation. The upstream and downstream wires are thermistors enabling operation in the calorimetric mode. This design provides a high temperature gradient and a homogeneous temperature distribution along the wires. The sensor operates in both constant current and constant temperature modes, with a feedback on current enabled by uncoupling heating and measurement. Welded on a flexible printed circuit, the sensor was flush mounted on the wall of a turbulent boundary layer wind tunnel. The experiments, conducted in both attached and separated flow configurations, quantify the sensor response to a bi-directional wall shear stress up to 2.4Pa and demonstrate the sensor ability to detect flow separation.

      PubDate: 2017-09-20T16:00:13Z
       
  • MoS2 based photosensor detecting both light wavelength and intensity
    • Authors: Yu Tong; Yi Liu; Daniel S.H. Chan; John Thong; Chunxiang Zhu
      Abstract: Publication date: Available online 19 September 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Yu Tong, Yi Liu, Daniel S.H. Chan, John Thong, Chunxiang Zhu
      MoS2 is a typical two-dimensional transition-metal dichalcogenide material, which has been researched intensively in the past few years. It is believed to hold promises in sensing and optical applications because of its intriguing electrical and optical properties. In this report, we have fabricated a MoS2 based photosensor which can detect both light wavelength and intensity. Firstly, the characteristics of MoS2 device under light irradiation and corresponding photoluminescence are measured at air ambient. Two mechanisms, carrier generation and gas desorption, are found to contribute to the drain current of MoS2 device under light irradiation. Following that, measurements of MoS2 device under different light irradiation and gas adsorption conditions are carried out to understand their relationship. Based on the relationship between gas desorption and photoresponse, it is revealed that the photoresponse has a strong dependence on its intensity and wavelength, which enables a photosensor capable of detecting both light intensity and wavelength.

      PubDate: 2017-09-20T16:00:13Z
      DOI: 10.1016/j.sna.2017.09.028
       
  • Highly sensitive flexible proximity tactile array sensor by using carbon
           micro coils
    • Authors: Tien Dat Nguyen; Hyo Seung Han; Hyeon-Yeong Shin; Canh Toan Nguyen; Hoa Phung; Hung Van Hoang; Hyouk Ryeol Choi
      Abstract: Publication date: Available online 18 September 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Tien Dat Nguyen, Hyo Seung Han, Hyeon-Yeong Shin, Canh Toan Nguyen, Hoa Phung, Hung Van Hoang, Hyouk Ryeol Choi
      Recently, the new generation of robotics, called soft robotics, are exploited by soft materials as the revolutionary tools which innovate the current challenges. In this paper, we propose a novel dual mode array sensor based on the carbon microcoils (CMC) in soft dielectric elastomer substrate material. It can detect the distance to the object as well as the pressure when it has contact. In the first, the design of sensor structure and its properties are investigated. Various experiments are performed on the dielectric substrates, electrode structures, and the target objects by changing electrical impedance formed by CMC under the alternating current (AC) excitation voltage with the dominant excitation frequency at 100kHz. Secondly, the tactile sensing, and proximity sensing, that is dual mode sensing performance are examined with respect to repeatability, reversibility, durability, sensitivity, and hysteresis. In the next, the sensor signal processing for measuring impedance (LCR) are analyzed with an analog signal processing, analog switching circuit, and digital processing. Finally, we successfully demonstrate the performance of 10×10 proximity tactile sensor which is capable of detecting a 30mg (300mgF) droplet and applied pressure up to 330kPa approximately, and detected the distance of the metal object from 150mm to touch on to the CMC sensor surface. Moreover, the 16×16 multi-cell arrays tactile sensor with 2mm electrode pads spatial-resolution activated in 32×32×0.6mm3 is performed to show the high resolution performance as well as multiple touches on independent cells.

      PubDate: 2017-09-20T16:00:13Z
      DOI: 10.1016/j.sna.2017.09.013
       
  • Fabrication of Piezoresistive Based Pressure Sensor via Purified and
           Functionalized CNTs/PDMS Nanocomposite: Toward Development of Haptic
           Sensors
    • Authors: Saman Azhari; Amin Termeh Yousefi; Hirofumi Tanaka; Amin Khajeh; Nico Kuredemus; Mani Mansouri Bigdeli; Mohd Nizar Hamidon
      Abstract: Publication date: Available online 17 September 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Saman Azhari, Amin Termeh Yousefi, Hirofumi Tanaka, Amin Khajeh, Nico Kuredemus, Mani Mansouri Bigdeli, Mohd Nizar Hamidon
      In this work, we reported a chemically modified technique via screen printing method to fabricate carbon nanotubes (CNTs)/Polydimethylsiloxane (PDMS) nanocomposite to monitor the piezoresistive behavior of nanocomposite while applying pressure. Raman, UV/Vis and HRTEM results were utilized to verify the quality of CNTs, purified through chemical and physical treatments; carboxylic and hydroxylic functional groups were determined via FTIR. The optimum dispersion ratio of the nanocomposite was observed by FESEM images which clearly show the consistent dispersion of CNTs coated by PDMS. Furthermore, I–V characterization of the developed nanocomposite indicates change in resistivity for a few orders of magnitude before and after treatment in addition to resistance variation as a result of different applied pressures. These results indicate the importance of CNTs treatment prior to nanocomposite fabrication in order to obtain lower percolation threshold. Obtained results are useful in development of haptic sensor, artificial finger, and brain like devices for robotics applications.
      Graphical abstract image

      PubDate: 2017-09-20T16:00:13Z
      DOI: 10.1016/j.sna.2017.09.026
       
  • Rate dependent non-linear magneto-electro-mechanical response of layered
           magneto electric composites: Theoretical and Experimental approach
    • Authors: Sk.M. Subhani; S. Maniprakash; A. Arockiarajan
      Abstract: Publication date: Available online 14 September 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Sk.M. Subhani, S. Maniprakash, A. Arockiarajan
      Magnetoelectric (ME) composite structures have a wide range of applications in various industries due to the presence of ME coupling behavior. In the present work, ME coupling behavior is accounted for by considering mechanically bonded ferroelectric and magnetostrictive phases. Firstly, the rate dependent behaviors of ferroic phases are observed by performing experimental investigations at room temperature. To depict the response of ferroic materials, thermodynamically consistent model is proposed. In order to account for the rate dependent behavior, a penalty function is introduced. Simulation studies have been performed by obtaining model parameters from the experimental studies and results are presented. Simulated results are in good agreement with the experimental data. This work is further extended to capture the response of ME composites by employing a simple homogenization technique. Mechanical, electrical and ME coupling behavior of ME composites are characterized in terms of effect of the volume fraction of the ferroic phases.

      PubDate: 2017-09-15T08:34:02Z
      DOI: 10.1016/j.sna.2017.09.018
       
  • Multilayered ceramic heterostructures of lead zirconate titanate and
           nickel-zinc ferrite for magnetoelectric sensor elements
    • Authors: D.Yu Karpenkov; A.A. Bogomolov; A.V. Solnyshkin; A.Yu Karpenkov; V.I. Shevyakov; A.N. Belov
      Abstract: Publication date: Available online 14 September 2017
      Source:Sensors and Actuators A: Physical
      Author(s): D.Yu Karpenkov, A.A. Bogomolov, A.V. Solnyshkin, A.Yu Karpenkov, V.I. Shevyakov, A.N. Belov
      The preparation method of magnetoelectric multilayered ceramic heterostructures was suggested, and series of the rectangular and disk shape samples were produced on the base of this method. The maximum value of a magnetoelectric voltage coefficient α E =35V/(cm×Oe) was observed for the eleven-layered rectangular specimen at the electromechanical resonance frequency fr =144kHz, НDC =84Oe, and НAC =2.5 Oe. The sensitivity to static magnetic fields is equal to 3.5×10−2 Oe, and the alternating field sensitivity is equal to 8×10−3 Oe.

      PubDate: 2017-09-15T08:34:02Z
      DOI: 10.1016/j.sna.2017.09.011
       
  • Charging Capacitors Using Single Crystal PMN-PT and PZN-PT Energy
           Harvesters Coupled with the SSHI Circuit
    • Authors: Zhengbao Yang; Zhaoye Qin; Jean Zu
      Abstract: Publication date: Available online 14 September 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Zhengbao Yang, Zhaoye Qin, Jean Zu
      Piezoelectric energy harvesting technology is regarded as a remedy to the short-life battery issue in low-power electronic devices, and has been extensively studied in the past two decades. Although a variety of new structures and mechanisms have been proposed for piezoelectric energy harvesters (PEHs), there is not much progress made on the piezoelectric materials that play a determinant role in PEHs performance. Most energy harvesters are still constructed with lead zirconate titanate (PZT). Recently, the new-generation piezoelectric materials PMN-PT and PZN-PT single crystals are proposed and start to be used in transducers. Their electromechanical coupling factor (k33 ) is over 90%, and the piezoelectric coefficient (d33 ) can reach three times of that of PZT. This study characterizes the PMN-PT and PZN-PT single crystals used in energy harvesters, compared with the polycrystalline PZT, in terms of charging capacitors. Systematic discussions are presented on the voltage, power and energy responses, as well as the reverse coupling effect on the mechanical response and the self-discharge effect of capacitors. Furthermore, a self-powered synchronized switch harvesting on inductor (SSHI) circuit is constructed and tested with the new single-crystal based energy harvesters. Experiments indicate that PMN-PT and PZN-PT can significantly boost the charging capability of energy harvesters, and that performance can be further enhanced by the SSHI circuit.

      PubDate: 2017-09-15T08:34:02Z
      DOI: 10.1016/j.sna.2017.09.024
       
  • Influence of magnetic fields on the bias stability of atomic gyroscope
           operated in spin-exchange relaxation-free regime
    • Authors: Rujie Li; Wei Quan; Wenfeng Fan; Li Xing; Jiancheng Fang
      Abstract: Publication date: Available online 14 September 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Rujie Li, Wei Quan, Wenfeng Fan, Li Xing, Jiancheng Fang
      For the atomic gyroscope (AG) operated in spin-exchange relaxation-free (SERF) regime, the sensitivity to external magnetic fields has been suppressed while the ability to sense inertial rotations has been kept. Here, a theoretical relationship between the magnetic fields and the AG response is given, and the influence of field fluctuations on the systematic stability is also shown. The spin-exchange rate of the electron spins R se en and the relaxation rate of the nuclear spins R tot n aggravate the influence of the field component B x . Experimental results indicate that the contributions of long-term fluctuations in the fields, approximately 2.4pT/h for B x and 0.9pT/h for B y , to the bias stability are 2.19×10−2 deg/h and 5.29×10−4 deg/h. This work is not only valuable for understanding the field-suppression effect in SERF AG, but also provides a useful tool for identifying the influence of fields on the systematic stability.

      PubDate: 2017-09-15T08:34:02Z
      DOI: 10.1016/j.sna.2017.09.023
       
  • Low cost and anti-noise infrared device based on saw-tooth thermal
           isolation structure
    • Authors: Wu QinQin; Wang Yuanqing; Ren Shuping
      Abstract: Publication date: Available online 14 September 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Wu QinQin, Wang Yuanqing, Ren Shuping
      The low cost composite film pyroelectric infrared device with novel saw-tooth thermal isolation structure is reported in this paper. The pyroelectric sensor was fabricated by using PZT/P(VDF-TrFE) composites. The Rg of the voltage-mode readout-circuit was removed to reduce the cost. Use PCB V-cut process to fabricate saw-tooth thermal isolation structure to improve anti-noise performance of the device. The device that using improved readout-circuit and saw-tooth thermal isolation structure was prepared. The voltage responsivity (Rv), noise equivalent power (NEP) and detectivity (D*) of the device were calculated, the modulation frequency was 2.3 Hz-117.3Hz.

      PubDate: 2017-09-15T08:34:02Z
      DOI: 10.1016/j.sna.2017.09.025
       
  • Design, modeling and testing of a novel flexure-based displacement
           amplification mechanism
    • Authors: Lei-Jie Lai; Zi-Na Zhu
      Abstract: Publication date: Available online 14 September 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Lei-Jie Lai, Zi-Na Zhu
      This paper presents a novel flexure-based displacement amplification mechanism to increase the effective actuation stroke of piezoelectric actuator. The proposed mechanism consists of two L-shape lever-type mechanism and one bridge-type mechanism. The flexure hinges in this mechanism are all loaded in tension and bending, which can solve the potential buckling problems. The symmetrical distribution of the L-shape lever mechanisms can avoid the bending moments and lateral forces at the driving end to protect the piezoelectric actuator. An analytical model based on the stiffness matrix method for the calculations of displacement amplification ratio, input stiffness and natural frequency of the mechanism is constructed and optimal design is performed under certain constraints. The finite element analysis results are then given to validate the design model and a prototype of the amplification mechanism is fabricated for performances tests. The results of static and dynamic tests show that the proposed mechanism is capable of travel range of 288.3μm with motion resolution of 50nm, and the working resonance frequencies of the mechanism without and with the actuator mounted are 155Hz and 178Hz, respectively. The finite element analysis and the experimental results show that good static and dynamic performances are achieved, which verifies the effectiveness of the proposed mechanism.

      PubDate: 2017-09-15T08:34:02Z
      DOI: 10.1016/j.sna.2017.09.010
       
  • The effect of monohydric and polyhydric alcohols on silicon anisotropic
           etching in KOH solutions
    • Authors: Irena Zubel; Krzysztof P. Rola
      Abstract: Publication date: Available online 14 September 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Irena Zubel, Krzysztof P. Rola
      Tensioactive compounds, such monohydric or polyhydric alcohols cause that with an increase in their concentration in solutions, surface tension at the liquid-gas interface – γLG, and wetting angle at the interface silicon-solution – θLS decrease. It means that on both the surfaces an adsorption layer of the alcohol occurs. It results in lowering of etch rates of some silicon crystallographic planes. In this work, the values of γLG and θLS for selected monohydric and polyhydric alcohols (diols) have been compared and etch rates and morphologies of silicon substrates Si(100) and Si(110) etched in KOH solutions containing these alcohols have been determined. Advantages of diols and possibilities of their using in silicon anisotropic etching have been considered.
      Graphical abstract image

      PubDate: 2017-09-15T08:34:02Z
      DOI: 10.1016/j.sna.2017.09.022
       
  • Self-assembled Hierarchical Phenolphthalein Encapsulated Silica
           Nanoparticles: structural, optical and sensing response
    • Authors: Shumaila Islam; Noriah Bidin; Saira Riaz; Shahzad Naseem
      Abstract: Publication date: Available online 12 September 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Shumaila Islam, Noriah Bidin, Saira Riaz, Shahzad Naseem
      Exploration of novel meso-materials with higher surface areas is a major challenge in the rapidly expanding field of opto-chemical sensor devices. Therefore, synthesis and growth mechanism of surfactant CTAB assisted sol-gel based silica and phenolphthalein encapsulated silica nanoparticles (NPs) and their optical and pH sensing activities is reported at low temperature in this present communication. Hierarchical/ordered structures/architectures are observed after encapsulation of phenolphthalein by FE-SEM analysis. AFM analysis exhibits the formation of porous nanostructures with average surface roughness Ra ∼5.15nm which is reduced to Ra ∼4.98nm after encapsulation of phenolphthalein, whereas, particle size increased from 8nm to 13nm. N2 adsorption isotherms explain the meso-porous nature of the matrix with high surface area value of 443m2/g with a pore volume of 0.93cm3/g and pore diameter of 85.59Å. Experimental findings show that the prepared meso-silica-phenolphthalein frameworks have high thermal stability, low refractive index (1.33) with good optical transparency of 83%. Furthermore, the evanescent wave is used to selectively excite the phph molecules encapsulated in silica matrix and deposited on the Plastic Clad Silica fiber as cladding for sampling the aqueous media (pH solutions 2–12) surrounding the fiber. Highest sensing response is optimized for pH 12 within 1s with pink color indication. The improved structural and optical characteristics identify that the prepared optochemical nanosensor device has potential for fast detection of pH at dynamic range.
      Graphical abstract image

      PubDate: 2017-09-15T08:34:02Z
      DOI: 10.1016/j.sna.2017.09.020
       
  • DEAD-BEAT CONTROL BASED TRERMAL COMPENSATION FOR MICROMACHINED THERMAL GAS
           GYROSCOPE
    • Authors: Shiqiang Liu; Rong Zhu
      Abstract: Publication date: Available online 12 September 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Shiqiang Liu, Rong Zhu
      Micromachined thermal gas gyroscopes take advantages of simple structure, low cost, high shock resistance, and large measurement range by using thermally driven gas stream instead of solid proof mass as moving and sensitive element compared with conventional silicon or quartz gyroscopes. However, they suffer from temperature susceptibility, which degrades performances of the gyroscopes. It is important to investigate thermal mechanism behaving in sensor and build an effective thermal compensation method to guarantee the sensor accuracy. In this paper, Finite-Element-Model (FEM) simulation method is used to study the thermal behavior and the relationship between the thermal drift of the gyroscope and the working temperature of the heaters that thermally drives gas motion is established. On this basis, we propose a real-time thermal compensation scheme based on Alternating Dead-Beat Control (ADBC). ADBC is used to alternatively modulate the heaters to implement fast, small-overshoot, and precise temperature control so as to keep the working condition of the sensor steady. Experiments validate that the thermal compensation scheme is effective to eliminate the temperature drifts in scale factor and zero bias of the sensor, meanwhile improves the gyroscope sensitivity. Predictably, the ADBC based compensation methodology can be applied for other thermal sensors (e.g. thermal accelerometers, thermal anemometers).

      PubDate: 2017-09-15T08:34:02Z
      DOI: 10.1016/j.sna.2017.09.019
       
  • An optimized multi-classifiers ensemble learning for identification of
           ginsengs based on electronic nose
    • Authors: Xiyang Sun; Linfeng Liu; Zhan Wang; Jiacheng Miao; You Wang; Zhiyuan Luo; Guang Li
      Abstract: Publication date: Available online 9 September 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Xiyang Sun, Linfeng Liu, Zhan Wang, Jiacheng Miao, You Wang, Zhiyuan Luo, Guang Li
      This paper proposes an optimized two-layer Adaboost.M2 model, which resolves a multi-class identification issue for Chinese herbal medicine and aims to enhance the accuracy and reliability of classification. Various base classifiers with probabilistic outputs are integrated in first layer and then transferred to Adaboost.M2 iteration process. Classical fusion rules are verified for optimal combination of classifiers. Identification capacities of base classifiers are investigated using diversity measurement and supply some instructions for optimization of classifier sets. Experimental results show that optimal Adaboost.M2 model integrated with SVM, PNN and LDA achieves the best accuracy of 91.75%, compared to 87.62% from the best single classifier SVM. Corresponding fusion rules are validated with error sensitivity and mean rule is selected while the least error of 8.25% is arrived. The contribution of the paper is that the optimized two-layer Adaboost.M2 with multiple classifiers is a flexible tool to make valid probabilistic and precise prediction for E-nose application in Chinese herbal medicine. This approach also proposes an idea for various ensemble system application, supplies a feasible solution for online classification.

      PubDate: 2017-09-15T08:34:02Z
      DOI: 10.1016/j.sna.2017.08.052
       
  • A tactile sensor for measuring hardness of soft tissue with applications
           to minimally invasive surgery
    • Authors: Lei Zhang; Feng Ju; Yanfei Cao; Yaoyao Wang; Bai Chen
      Abstract: Publication date: Available online 9 September 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Lei Zhang, Feng Ju, Yanfei Cao, Yaoyao Wang, Bai Chen
      This paper presents a novel tactile sensor for measuring hardness of soft tissue in minimally invasive surgery (MIS). The proposed tactile sensor consists of a piezoelectric ceramic plate, a spiral metal plate and a probe. The resonant frequency of the sensor shifts when the sensor contact with a tissue. For restricting the impact brought by the effective mass of the tissue, the spiral metal plate is designed to reduce the resonant frequency of the sensor. Another feature of this sensor is that only one piece of lead zirconate titanate (PZT) is used as both actuator and sensing element. So the structure of the sensor is very simple which can be easily miniaturized and is suitable for MIS. The finite element analyses are carried out to verify the feasibility of the sensor and compare with the experimental results. Several silicone samples are used to test the performance of the sensor and the results show the ability of the sensor to measure hardness of soft tissue and detect lumps inside tissue.

      PubDate: 2017-09-15T08:34:02Z
      DOI: 10.1016/j.sna.2017.09.012
       
  • Optimal design of a double-vibrator ultrasonic motor using combination
           method of finite element method, sensitivity analysis and adaptive genetic
           algorithm
    • Authors: Zhaopeng Dong; Ming Yang
      Abstract: Publication date: Available online 7 September 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Zhaopeng Dong, Ming Yang
      Recent studies have shown that new devices with improved performance can be successful achieved by using optimization methods In this study, an optimal design of a double-vibrator ultrasonic motor using combination method of finite element method, sensitivity analysis and adaptive genetic algorithm is presented. The finite element method is the reliable method for modal and harmonic response analysis. The sensitivity analysis is employed to determine the optimal analysis parameters having high sensitivity to optimization objectives, which can significantly improve the efficiency of the optimization. The adaptive genetic algorithm is adopted to seek the optimal values of structural parameters, which is scientific and efficient for multi-objective optimization problems. After optimization, all of the design objectives have achieved significant improvements. To verify the effectiveness of this method, a prototype motor is manufactured according to the optimization results and its performance is measured. The measured results show that this method is available and effective for the optimal design of ultrasonic motors.

      PubDate: 2017-09-09T08:22:41Z
      DOI: 10.1016/j.sna.2017.09.006
       
  • Large area and ultra-thin compliant strain sensors for prosthetic devices
    • Authors: Vitor Sencadas; Rahim Mutlu; Gursel Alici
      Abstract: Publication date: Available online 4 September 2017
      Source:Sensors and Actuators A: Physical
      Author(s): Vitor Sencadas, Rahim Mutlu, Gursel Alici
      There is an increasing need to establish skin-like ultra-thin sensors which can directly be deposited (e.g. sprayed) on a soft active structure representing the limbs (e.g. fingers) of prosthetic devices such as a prosthetic hand. Such sensors are essential to control the actuation behaviour of the soft structure, and to obtain information about temperature of an object which the finger is touching. This study employed an inexpensive and scalable technique to place elastomeric sensors directly onto a monolithic structure representing the finger of a soft robotic prosthetic hand. The chemical affinity between the solvent used, and the soft elastomers (thermoplastic urethane, TPU, and styrene-butadiene-styrene, SBS) allowed the blending of the TPU and the SBS at the finger interface, creating a highly compliant piezoresistive sensor, that was directly deposited in the desired place. The bending movement of the three interphalangeal joints of the finger were recorded simultaneously. The sensing elements (i.e. soft strain sensors) showed an outstanding linearity between the change of resistance and the strain during the finger bending, with a gauge factor of ∼1, repeatability and stability (>10,000 cycles), fast response and low creep, with negligible mechanical and electrical hysteresis. These sensors have a significant potential to establish prosthetic devices with built-in sensing elements, paving the way towards prosthetic limbs compatible with natural control.

      PubDate: 2017-09-09T08:22:41Z
      DOI: 10.1016/j.sna.2017.08.051
       
 
 
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