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1
The effect of periodic magnetic force on a piezoelectric energy harvester
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
SENSORS AND ACTUATORS A-PHYSICAL
Yazar(lar) :
Yunus Uzun , Erol Kurt
Konu :
Energy harvester, Softening nonlinearity, Periodic magnetic force, Piezoelectric beam
Yıl :
2013
SENSORS AND ACTUATORS A-PHYSICAL
Yayıncı Web Sitesi
Kaydet
The response of a piezoelectric (PZT) harvester in pendulum shape is explored under a periodic magnetic field both theoretically and experimentally. The magnetic force F-m is found via fitting to a polynomial function including the third order of amplitude after the evaluation of magnetic simulations. F-m term dominates the dynamics of the piezoelectric (PZT) harvester with a certain frequency omega(m) and the excitation amplitude U-m. A clear softening effect is observed as function of excitation frequency. Besides, the output power estimation is in good agreement with the experimental results. While the amplitude changes sinusoidal, velocity of the pendulum tip especially includes a number of different high frequency components with growing amplitudes. The periodic excitation causes ripples at the maximal and minimal values of velocity. Excitation frequency omega(m) which differs from the natural frequency coo causes much complex velocity data with high frequency components. The averaged power P = 79 mu W can be obtained and power increases dramatically when the harvester is excited at the natural frequency. (C) 2012 Elsevier B.V. All rights reserved. Gazi University - Scientific Research Project UnitGazi University [BAP 07/2010-01]; TUBITAK Graduate School Programme ISMFATurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [2217] The authors acknowledge the support of Gazi University - Scientific Research Project Unit under the Project no. BAP 07/2010-01 and the support of TUBITAK Graduate School Programme ISMFA 2011 under no: 2217.

ISSN: 0924-4247
2
Spectral analysis for photoacoustic pressure sensor designs: Theoretical model improvement and experimental validation
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
SENSORS AND ACTUATORS A-PHYSICAL
Yazar(lar) :
Timucin Emre Tabaru , Sekip Esat Hayber , Serkan Keser , Omer Galip Saracoglu
Konu :
Pulsed laser photoacoustic method, Acoustic pressure sensor, Spectroscopy, Frequency domain solution, Photoacoustic wave equation, Theoretical model approach
Yıl :
2019
SENSORS AND ACTUATORS A-PHYSICAL
Yayıncı Web Sitesi
Kaydet
In the pulsed laser photoacoustic (PA) detection and spectroscopy applications, the fundamental frequency of the PA signal produced, and the sensor resonance frequency should be as close as possible to each other so that analyzes from the obtained signals can be performed effectively. In order to determine the fundamental frequency of the PA wave, a theoretical model approach based on the development of the frequency domain solution of the PA wave equation is presented for use in the PA pressure sensor designs. For the validation of the theoretical model approach, a PA experimental setup was established, and measurements were made in distilled water. The theoretical and the experimental PA frequency spectra were determined to be very compatible with each other. Thus, the theoretical model approach was experimentally validated. According to the theoretical model approach, fundamental frequency values obtained from the experimental measurement results were determined with an average accuracy of -/+ 4.212%. Furthermore, it has been determined that this value has fallen to -/+ 0.267% in the measurements. With the obtained results from the theoretical model approach, we propose that the PA pressure sensors with the more selective and narrower band can be designed for the more sensitive detection. Moreover, in this study the effects of different laser parameters such that pulse duration, and laser beam width, on the spectral content of the obtained PA signal are analyzed. These analyses will shed light on the vision of acoustic pressure sensor design by helping to select the most optimum parameters for the PA detection. (C) 2019 Elsevier B.V. All rights reserved. Research Fund of the Erciyes UniversityErciyes University [FDK-2016-6811, FDK-2016-6815] This work was supported by the Research Fund of the Erciyes University. Project numbers FDK-2016-6811 and FDK-2016-6815. The authors would like to thank Erciyes University Clinical Engineering Research and Application Center for their support in the research activities among the staffs.

ISSN: 0924-4247
Sınıflandırma :
Fizik %49
3
Laser synthesized gold nanoparticles for high sensitive strain gauges
Dergi Makalesi

Dergi Makalesi Open Access
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors and Actuators A: Physical
Yazar(lar) :
S. Burzhuev , A. Dana , B. Ortac
Konu :
Laser ablation, Gold nanoparticles, Gold nanoparticle films, Quantum tunneling effect, Strain gauges
Yıl :
2013
Sensors and Actuators A: Physical
Yayıncı Web Sitesi Tam Metin
Kaydet
We demonstrate high strain sensitivity property of gold nanoparticle (Au-NP) thin films fabricated on flexible polydimethylsiloxane (PDMS) substrates. This behavior is attributed to quantum tunneling effect that is highly dependent on nanoparticle separation. Au-NPs were synthesized in water by nanosecond laser ablation method. The clean surface providing high tunneling decay constant, size of the Au-NPs and Au-NPs aggregate clusters offer advantages for high sensitivity strain sensor. We prepared Au-NPs films on flexible PDMS substrate by using hands-on drop-cast method. To obtain high gauge factor (g factor), we investigated the nanoparticles concentration on the substrate. Laser-generated Au-NPs films demonstrated g factor of ∼300 for higher than 0.22% strain and ∼80 for the strain lower than 0.22% strain, which is favorably comparable to reported sensitivities for strain sensors based on Au-NPs. Mechanical characterizations for the prolonged working durations suggest long term stability of the strain sensors. We discuss several models describing conductance of films in low and high strain regimes.
DOI : 10.1016/j.sna.2013.08.034
Anahtar Kelimeler : Laser ablation, Gold nanoparticles, Gold nanoparticle films, Quantum tunneling effect, Strain gauges, Article
Cilt: 203
ISSN: 0924-4247
Sayfa: 131-136
Sınıflandırma :
4
Development of a distance-independent wireless passive RF resonator sensor and a new telemetric measurement technique for wireless strain monitoring
Dergi Makalesi

Dergi Makalesi Open Access
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors and Actuators, A: Physical
Yazar(lar) :
A. Alipour , E. Unal , S. Gokyar , Hilmi Volkan Demir
Konu :
Inductive coupling, Passive RF resonator, Strain sensor, Wireless monitoring
Yıl :
2017
Sensors and Actuators, A: Physical
Yayıncı Web Sitesi Tam Metin
Kaydet
We proposed and developed a novel wireless passive RF resonator scheme that enables telemetric strain sensing avoiding the need for calibration at different interrogation distances. The specific architecture of the proposed structure allows for strong inductive coupling and, thus, a higher wireless signal-to-noise ratio. Here, in operation, the frequency scan of the sensor impedance was used to measure simultaneously both the impedance amplitude and resonance frequency. Using this wireless sensor, we further introduced a new telemetric monitoring modality that employs full electrical characteristics of the system to achieve correct strain extraction at any interrogation distance. In principle, any deformation of the sensor structure results in the resonance frequency shift to track strain. However, changing of the interrogation distance also varies the inductive coupling between the sensor and its pick-up antenna at the interrogation distance. Therefore, at varying interrogation distances, it is not possible to attribute an individual resonance frequency value solely to an individual strain level, consequently resulting in discrepancies in the strain extraction if the interrogation distance is not kept fixed or distance-specific calibration is not used. In this work, we showed that by using both the proposed passive sensor structure and wireless measurement technique, strain can be successfully extracted independent of the interrogation distance for the first time. The experimental results indicate high sensitivity and linearity for the proposed system. These findings may open up new possibilities in applications with varying interrogation distance for mobile wireless sensing. © 2017 Elsevier B.V.
DOI : 10.1016/j.sna.2017.01.010
Anahtar Kelimeler : Inductive coupling, Passive RF resonator, Strain sensor, Wireless monitoring, Article
Cilt: 255
ISSN: 0924-4247
Sayfa: 87-93
Sınıflandırma :
5
Comparative study of ZnCr2O4-K2CrO4 ceramic humidity sensor using computer controlled humidity measurement set-up
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors and Actuators A-Physical
Yazar(lar) :
Neşe Kavasoğlu , Abdulkadir Sertap Kavasoğlu , M Bayhan
Konu :
humidity measurement set-up, ZnCr2O4-K2CrO4 ceramic humidity sensors, SHT75
Yıl :
2006
Sensors and Actuators A-Physical
Yayıncı Web Sitesi
Kaydet
A home-made ZnCr2O4-KCrO4 ceramic humidity sensor was studied using a commercially available reference humidity sensor, SHT75 from Sensirion. The main advantages of our developed set-up for humidity measurements are low cost and high resolution yielding a full set of information on the variation of humidity. Air moisture sensitive ceramic body prepared using K2CrO4 (20%) in ZnCr2O4 was produced from the solid-state reaction between zinc oxide and chromite oxide at high temperatures. The dc resistance as a function of relative humidity (RH) showed a strong dependence, decreasing over several orders of magnitude with increasing humidity being a smooth exponential. The air moisture dependent resistance of the ceramic sensor is converted into voltage signals using a circuitry. Basically it consists of an operational amplifier and an A/D converter. Long-term stability measurements showed that ZnCr2O4-K2CrO4 ceramic system has potential use as an active material in humidity sensors. (C) 2005 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : humidity measurement set-up, ZnCr2O4-K2CrO4 ceramic humidity sensors, SHT75, article
Cilt: 126
Sayı: 2
ISSN: 0924-4247
Sınıflandırma :
6
MEMS cantilever sensor array oscillators: Theory and experiments
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors and Actuators A: Physical
Yazar(lar) :
S. Z. Lulec , U. Adiyan , Göksen Göksenin Yaralıoğlu , Y. Leblebici , H. Urey
Konu :
Biosensors, MEMS cantilever sensor arrays, Multiple self-sustained oscillation, Interferometric readout, Diffraction grating
Yıl :
2016
Sensors and Actuators A: Physical
Yayıncı Web Sitesi
Kaydet
This paper demonstrates that an array of cantilever sensors can be operated simultaneously at resonance using a single actuator and a single photodetector. Self-sustained oscillations (SSOs) of cantilevers can be achieved in a feed-back loop using gain saturation mechanism in the electronics. Multiple cantilevers require separate saturation mechanisms and separate sensing electronics for each channel. We introduced optical non-linearity using diffraction gratings at the tip of each cantilever which provide separate saturation non-linearity, enabling a single detector based oscillator array. Two-cantilever SSO operation is investigated analytically, and the multiple frequency oscillation criteria are established. Cross-coupling between the oscillation frequencies has been investigated by using this multi cantilever model. The proposed model will be helpful to design dynamic‑mode MEMS (Micro-electro-mechanical systems) cantilever sensor arrays with the desired functionality and cross-talk levels. This multiple SSO operation can be used in conjunction with dense cantilever arrays for various biosensor applications. Moreover, the model can also be useful to understand the operation of any kind of multiple simultaneous oscillator systems, which employs a single feed-back loop. We also present experimental results that confirm our model.
Anahtar Kelimeler : Article

ISSN: 0924-4247
Sınıflandırma :
7
Herbicide/pesticide sensing with metamaterial absorber in THz regime
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors and Actuators, A: Physical
Yazar(lar) :
Khwanchai Tantiwanichapan , Habibe Durmaz
Konu :
Metamaterials, Pesticide Sensing, Plasmonics, Terahertz Absorber
Yıl :
2021
Sensors and Actuators, A: Physical
Yayıncı Web Sitesi
Kaydet
Terahertz (THz) technology has been attracted great interest in many research areas over the years, especially THz plasmonics for sensing applications since intra- and inter-molecular vibrations are within the THz range. The sensitivity of free-space THz detection can be boosted up by use of metamaterials (MM), which are artificial structures in subwavelength scale of the incident light. These artificial materials present high electric field enhancement and high sensitivity to the change in their surroundings. In this article, residual herbicides/pesticides have been investigated both theoretically and experimentally with a polarization-insensitive THz metamaterial absorber (MMA) composed of dielectric-metal disk antennas. Our THz MMA can detect as small as 5 ppM of commonly used herbicide/pesticide, namely paraquat and glyphosate. The results show that sensitivity is greatly improved by using THz MMA, with the limit of detection (LOD) of these herbicides/pesticides reaching to 5 ppM. These results indicate that THz MMA platform could be a valuable method for highly sensitive THz applications in food quality and safety control. We believe, our sensor platform based on general c-mos technology fabrication could be a potential detection tool for herbicides/ pesticides residues in agriculture and food products.
Anahtar Kelimeler : Metamaterials, Pesticide Sensing, Plasmonics, Terahertz Absorber, article
Cilt: 331
Sınıflandırma :
8
Deposition of ZnO thin films by RF&DC magnetron sputtering on silicon and porous-silicon substrates for pyroelectric applications
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors and Actuators, A: Physical
Yazar(lar) :
K. Cicek , T. Karacali , H. Efeoglu , B. Cakmak
Konu :
Porous Si, Pyroelectric sensor, Pyroelectricity, ZnO
Yıl :
2017
Sensors and Actuators, A: Physical
Yayıncı Web Sitesi
Kaydet
In this study, the temperature response of ZnO thin film is investigated in an attempt to enhance its pyroelectric performance. The film is formed on PS and Si substrates utilizing RF&DC magnetron sputtering deposition technique. The outcome of study reveals a pyroelectric coefficient observed from ZnO film on PS which is 40 times higher than that on Si and a pyroelectric voltage as high as 2.4 V due to PSs profound effect on film formation, large surface to volume area and low thermal conductivity. Thus, this study can lead the way to a robust, reliable and more efficient pyroelectric operation of ZnO with employment of PS structure. © 2017 Elsevier B.V.
Anahtar Kelimeler : Porous Si, Pyroelectric sensor, Pyroelectricity, ZnO, article
Cilt: 260
ISSN: 0924-4247
9
The gamma irradiation responses of yttrium oxide capacitors and first assessment usage in radiation sensors
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors And Actuators A-Physical
Yazar(lar) :
Saleh Abubakar , Senol Kaya , Huseyin Karacali , Ercan Yilmaz
Konu :
Alternative dielectric film, Y2O3 MOS capacitors, Oxide trapped charges, Radiation effects, Radiation sensors
Yıl :
2017
Sensors And Actuators A-Physical
Yayıncı Web Sitesi
Kaydet
Co-60 gamma irradiation responses of the Y2O3 MOS capacitors were investigated, and initial assessment of the Y2O3 dielectrics used in gamma radiation sensors was discussed. We analyzed the effects of applied radiation from flat-band and mid-gap voltage shifts, and also capacitance-voltage measurements were obtained before and after irradiation. It has been observed that the measured capacitance is almost constant with irradiation and the basic modification in flat band shifts toward more positive voltages due to negative charge accumulation, thanks to trap centers in the MOS capacitors. The reason of negative charge trapping in the devices structure may be attributed to ionized Yttrium atoms and cluster of the oxygen vacancies occurred by irradiation. Also, a linear dose flat band relation has been observed, and irradiation sensitivity was found to be 10.8 0.43 mViGy for Y2O3 calculated for five different capacitors, which is more sensitive than the conventional SiO2 dielectric layers. The higher sensitivity is probably due to the high trapped efficiency in the Y2O3 dielectrics. On the other hand, the generated oxide traps densities increase with irradiation while interface state density trend varies by irradiation. This behavior for interface states was attributed to the passivation of the dielectric layer from the semiconductor. The charge accumulation in the MOS capacitors is in the order of 1010-1011 cm(-2) for the given dose range. This did not cause any significant device degradation through its operation. Consequently, the irradiation does not significantly affect the device operation. Especially, for radiation measurements system with linear dose performance and sensitivity, Y2O3 may be a promising future gate dielectric material candidate for radiation sensors in given radiation dose range. (C) 2017 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : Alternative dielectric film, Y2O3 MOS capacitors, Oxide trapped charges, Radiation effects, Radiation sensors, article
Cilt: 258
ISSN: 0924-4247
Sınıflandırma :
10
A room temperature acetone sensor based on synthesized tetranitro-oxacalix4arenes: Thin film fabrication and sensing properties
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors and Actuators, A: Physical
Yazar(lar) :
Sibel Şen , Ferah Cömert Önder , Rifat Çapan , Mehmet Ay
Konu :
Tetranitro-oxacalix4arene, Organic Thin Films, Surface Plasma Resonance, Weak Interactions, Acetone Sensing
Yıl :
2020
Sensors and Actuators, A: Physical
Yayıncı Web Sitesi
Kaydet
Çapan, Rifat (Balikesir Author) Tetranitro-oxacalix[4]arenes were prepared to determine their thin film fabrication and gas sensing applications. Firstly, tetranitro-oxacalix[4]arenes (1-3) were synthesized via nucleophilic aromatic sub-stitution reaction (SNAr) using substituted resorcinol derivatives and 1,5-difluoro-2,4-dinitrobenzene with moderate to high yields. Later, successfully synthesized materials were utilized to construct thin films using the spin coating method and the characterization of the deposited films was performed with UV-vis and surface plasmon resonance (SPR). Characterization results indicated that high-quality spin coated thin films were prepared using these materials. The sensing abilities of the spin-coated thin films of tetranitro-oxacalix[4]arenes (1-3) were tested using the SPR method for volatile organic vapours of acetone, chloroform, toluene, ethanol and benzene. High concentration sensitivity values of 0.0700 x 10(-3), 0.1001 x 10(-3) and 0.8653 x 10(-3) with normalized response/ppm unit for acetone vapour were obtained for thin films (1-3), respectively. The sensors obtained using especially thin films 1 and 3 showed high responses toward acetone even at low concentration ranges between 3.8-15.2 ppm. These sensors have the advantages of high sensitivity, reusability and reproducibility of results which make them compatible for practical acetone-detection applications.
Anahtar Kelimeler : Tetranitro-oxacalix4arene, Organic Thin Films, Surface Plasma Resonance, Weak Interactions, Acetone Sensing, article

ISSN: 0924-4247
11
Mitigation of high harmonicity and design of a battery charger for a new piezoelectric wind energy harvester
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
SENSORS AND ACTUATORS A-PHYSICAL
Yazar(lar) :
Yahia Bouzelata , Erol Kurt , Yunus Uzun , Rachid Chenni
Konu :
Piezoelectric, Wind Energy, Charger, Buck Converter, Battery
Yıl :
2018
SENSORS AND ACTUATORS A-PHYSICAL
Yayıncı Web Sitesi
Kaydet
A new piezoelectric wind energy harvester (PWEH) implementation and its power conversion system design have been studied. The new PWEH is a portable, economic, easy-mounted, and contactless machine exerting the elastic piezoelectric layers with permanent magnets (PMs). Although a single piezoelectric layer has an ideal sinusoidal waveform from its output terminals, the combined rotating system having multiple layers give complicated responses due to the electromechanical damping, high frequency mechanical vibrations and electromagnetic nonlinearities. In the current work, for instance, three layers generate three different waveforms with high harmonics. Thus, the output waveforms of such multiple layer low power-scale systems require special attention to gain the maximal power from such low scale harvesters. Indeed, electrical power generation from complicated voltage waveforms and charging efficiency have become main tasks for those low power systems. The proposed rectifier is joined to a capacitor-inductor output filter to ensure high quality DC - bus voltage by ripple mitigation function. An effective control strategy is also carried out for the voltage - mode control (VMC) method in order to control the DC-DC buck converter in such a way that it may guarantee a smooth output DC voltage. Then the later can be applied to charge storage unit such as a lead-acid type electrochemical battery for the future numerous low power applications. The proposed circuitry is successful to mitigate the harmonics of the voltage waveforms from the terminals of three piezoelectric layers with high THD values (i.e. 169.16%, 51.75% and 42.64%). In addition, the proposed PWEH has an ability to charge the battery with a stable output rectified voltage at 40V by enabling a linear increase in the State-Of-Charge (SOC) from 0% to 18% after 4 s till the battery is fully charged.
Anahtar Kelimeler : Piezoelectric, Wind Energy, Charger, Buck Converter, Battery, article
Cilt: 273
ISSN: 0924-4247
Sınıflandırma :
12
Attractive method for thickness-independent permittivity measurements of solid dielectric materials
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors and Actuators, A: Physical
Yazar(lar) :
Bayburt Üniversitesi
Konu :
Branch-index value, Permittivity measurement, Reference-plane invariant, Solid materials, Thickness-independent, Branch index, Branch-index value, Reference-plane invariant, Sample thickness, Solid material, Thickness-independent, Permittivity, Permittivity measurement, Separation, Uncertainty analysis, Dielectric materials, Branch-index value, Permittivity measurement, Reference-plane invariant, Solid materials, Thickness-independent, Branch index, Branch-index value, Reference-plane invariant, Sample thickness, Solid material, Thickness-independent, Permittivity, Permittivity measurement, Separation, Uncertainty analysis, Dielectric materials
Yıl :
2014
Sensors and Actuators, A: Physical
Yayıncı Web Sitesi Piri Tam Metin Bulucu
Kaydet
We propose a non-resonant-type method for reference-plane invariant and thickness-independent permittivity measurement of solid dielectric materials when there is no information from permittivity. To achieve this, we derive a branch-index-independent function and verify that it determines the sample thickness and permittivity without resorting to finding the correct branch index value for three different measurement scenarios: (a) measurements at closely separated frequencies of non-dispersive samples, (b) measurements at largely separated frequencies of non-dispersive samples, and (c) measurements at largely separated frequencies of dispersive samples. Via a differential uncertainty analysis, the effect of inaccurate sample thickness on permittivity determination is also presented for demonstration of the improvement achieved by our method. For validation, we measured the permittivity of an approximately 20 mm PTFE sample using the presented method and compared its result with those from other similar methods. From the comparison, we note that the accuracy of tested methods from literature drastically decreases when accurate information of sample thickness is not known (in addition to a further decrease in accuracy when correct transformation factors from reference-planes are not known a priori), while the accuracy of our method is not influenced. © 2013 Elsevier B.V.
DOI : 10.1016/j.sna.2013.11.032
Anahtar Kelimeler : Branch-index value, Permittivity measurement, Reference-plane invariant, Solid materials, Thickness-independent, Branch index, Branch-index value, Reference-plane invariant, Sample thickness, Solid material, Thickness-independent, Permittivity, Permittivity measurement, Separation, Uncertainty analysis, Dielectric materials, Branch-index value, Permittivity measurement, Reference-plane invariant, Solid materials, Thickness-independent, Branch index, Branch-index value, Reference-plane invariant, Sample thickness, Solid material, Thickness-independent, Permittivity, Permittivity measurement, Separation, Uncertainty analysis, Dielectric materials, article
Cilt: 206
ISSN: 0924-4247
Sınıflandırma :
Fizik %68
13
A versatile plug microvalve for microfluidic applications
Dergi Makalesi

Dergi Makalesi Open Access
Kaynak 1:
DSpace Makaleler
Kaynak 2:
DSpace Makaleler
Yayıncı :
Sensors and Actuators, A: Physical
Yazar(lar) :
M. T. Guler , P. Beyazkilic , C. Elbuken
Konu :
Colorimetric TNT assay, Microvalve, Portable microfluidics, Valve, Chemical detection, Flow of fluids, Fluidic devices, Microchannels, Molds, Polydimethylsiloxane, Silicones, Valves (mechanical), Chemical agent detection, Micro fluidic applications, Micro fluidic system, Micro valves, Modes of operation, Multiple materials, Polydimethylsiloxane PDMS, Repetitive operations, Microfluidics
Yıl :
2017
Sensors and Actuators, A: Physical
Tam Metin
Kaydet
Most of the available microvalves include complicated fabrication steps and multiple materials. We present a microvalve which is inspired from macroplug valves. The plug microvalve is fabricated by boring a hole through a rigid cylindrical rod and inserting it through a microfluidic chip. It simply functions by rotating the rod which aligns or misaligns the valve port with the microchannel. The rod is made up of a rigid material for applying the valve to an elastic polydimethylsiloxane (PDMS) microchannel. The valve can also be used for a rigid channel by inserting the rod into an elastic tubing. Therefore, the presented microvalve can be used for both elastomeric and thermoplastic channels. The plug microvalve can be applied to a prefabricated microchannel and does not require modification of the mold design. We have verified the repeatability and robustness of the valve by repetitive operation cycles using a servo motor. The plug microvalve is adaptable to numerous microfluidic applications. We have shown three modes of operation for the microvalve including fluid flow control across multiple intersecting channels. Integrating the microvalve to some commonly used microfluidic designs, we demonstrated the versatility and the practicality of the microvalve for controlling flow focusing, microdroplet sorting and rapid chemical agent detection. This low-cost microvalve significantly minimizes the prototyping time for microfluidic systems.
DOI : 10.1016/j.sna.2017.09.001
Anahtar Kelimeler : Colorimetric TNT assay, Microvalve, Portable microfluidics, Valve, Chemical detection, Flow of fluids, Fluidic devices, Microchannels, Molds, Polydimethylsiloxane, Silicones, Valves (mechanical), Chemical agent detection, Micro fluidic applications, Micro fluidic system, Micro valves, Modes of operation, Multiple materials, Polydimethylsiloxane PDMS, Repetitive operations, Microfluidics, Article
Cilt: 265
ISSN: 0924-4247
Sayfa: 224-230
Sınıflandırma :
14
Improvements in deterministic error modeling and calibration of inertial sensors and magnetometers
Dergi Makalesi

Dergi Makalesi Open Access
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors and Actuators, A: Physical
Yazar(lar) :
G. Secer , B. Barshan
Konu :
Accelerometer, Deterministic error modeling, Ellipsoid parameter estimation, Gyroscope, In-field calibration, Inertial sensors, Levenberg-Marquardt algorithm, Measurement model, Particle swarm optimization, Model parameter estimation, Magnetometer
Yıl :
2016
Sensors and Actuators, A: Physical
Yayıncı Web Sitesi Tam Metin
Kaydet
We consider the deterministic modeling, calibration, and model parameter estimation of two commonly employed inertial measurement units based on real test data acquired from a flight motion simulator. Each unit comprises three tri-axial devices: an accelerometer, a gyroscope, and a magnetometer. We perform the deterministic error modeling and calibration of accelerometers based on an improved measurement model, and the technique we propose for gyroscopes lowers costs by eliminating the need for additional sensors and relaxing the test bed requirement. We present an extended measurement model for magnetometers that reduces calibration errors by modeling orientation-dependent hard-iron errors in a gimbaled angular position-control machine. While we employ the model-based Levenberg-Marquardt optimization algorithm for the parameter estimation of accelerometers and magnetometers, we use a model-free evolutionary optimization algorithm (particle swarm optimization) for estimating the calibration parameters of gyroscopes. Errors are considerably reduced as a result of proper modeling and calibration. © 2016 Elsevier B.V.
DOI : 10.1016/j.sna.2016.06.024
Anahtar Kelimeler : Accelerometer, Deterministic error modeling, Ellipsoid parameter estimation, Gyroscope, In-field calibration, Inertial sensors, Levenberg-Marquardt algorithm, Measurement model, Particle swarm optimization, Model parameter estimation, Magnetometer, Article
Cilt: 247
ISSN: 0924-4247
Sayfa: 522-538
Sınıflandırma :
15
High-resolution imaging of elastic properties using harmonic cantilevers
Dergi Makalesi

Dergi Makalesi Open Access
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors and Actuators A: Physical
Yazar(lar) :
O. Sahin , G. Yaralioglu , R. Grow , S. F. Zappe , Abdullah Atalar , C. Quate , O. Solgaard
Konu :
Atomic force microscope, Cantilever, Elastic properties, Tapping-mode, Elastic properties, Flexural resonance, Tapping mode, Vibration spectrum, Atomic force microscopy, Cantilever beams, Elasticity, Imaging techniques, Natural frequencies, Stiffness, Thin films, Micromachining
Yıl :
2004
Sensors and Actuators A: Physical
Yayıncı Web Sitesi Tam Metin
Kaydet
We present a micromachined scanning probe cantilever, in which a specific higher-order flexural mode is designed to be resonant at an exact integer multiple of the fundamental resonance frequency. We have fabricated such cantilevers by reducing the stiffness of the third order flexural mode relative to the fundamental mode, and we have demonstrated that these cantilevers enable sensing of non-linear mechanical interactions between the atomically sharp tip at the free end of the cantilever and a surface with unknown mechanical properties in tapping-mode atomic force microscopy. Images of surfaces with large topographical variations show that for such samples harmonic imaging has better resolution than standard tapping-mode imaging.
DOI : 10.1016/j.sna.2003.11.031
Anahtar Kelimeler : Atomic force microscope, Cantilever, Elastic properties, Tapping-mode, Elastic properties, Flexural resonance, Tapping mode, Vibration spectrum, Atomic force microscopy, Cantilever beams, Elasticity, Imaging techniques, Natural frequencies, Stiffness, Thin films, Micromachining, Article
Cilt: 114
Sayı: 2-3
ISSN: 0924-4247
Sayfa: 183-190
Sınıflandırma :
16
Tape'n roll inertial microfluidics
Dergi Makalesi

Dergi Makalesi
Kaynak 1:
DSpace Makaleler
Kaynak 2:
DSpace Makaleler
Yayıncı :
Sensors and Actuators A: Physical
Yazar(lar) :
Mohammad Asghari , Murat Serhatlıoğlu , M. T. Güler , Çağlar Elbüken
Konu :
Particle focusing, Inertial focusing, 3D microfluidics, Flexible microfluidics
Yıl :
2019
Sensors and Actuators A: Physical
Piri Tam Metin Bulucu
Kaydet
Particle focusing and separation in microfluidic devices are critical for biological and medical applications. Inertial microfluidics is used for high throughput bio-particle focusing and separation. Most of the inertial microfluidic systems use planar structures for squeezing the particles in streams. Particle manipulation in 3D structures is often overlooked due to the complexity of the fabrication. In this study, we introduce some novel microchannel designs for inertial microfluidics by using a simple fabrication method that allows construction of both 2D and 3D structures. First, inertial migration of particles in 2D layouts including straight, spiral, and square spiral channels is investigated. Afterward, by applying a “tape’n roll” method, helical and double oriented spiral channels are configured and unexplored inertial migration behaviours are observed. Thanks to the simplicity of the fabrication and the unique characteristics of the new designs, high performance microfluidic inertial migration results can be obtained without any need for complicated microfabrication steps. The design optimization cycle can also be shortened using a computational approach we introduce in this study.
DOI : 10.1016/j.sna.2019.111630
Anahtar Kelimeler : Particle focusing, Inertial focusing, 3D microfluidics, Flexible microfluidics, Article
Cilt: 299
ISSN: 0924-4247
Sayfa: 111630-1-111630-9
Sınıflandırma :
17
Capacitive detection of single bacterium from drinking water with a detailed investigation of electrical flow cytometry
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors And Actuators A-Physical
Yazar(lar) :
Mustafa Tahsin Guler , Ismail Bilican
Konu :
Microfluidics, Bacteria, Capacitive detection, Simulation
Yıl :
2018
Sensors And Actuators A-Physical
Yayıncı Web Sitesi Piri Tam Metin Bulucu
Kaydet
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. (C) 2017 Elsevier B.V. All rightsreserved.
DOI : 10.1016/j.sna.2017.12.008
Anahtar Kelimeler : Microfluidics, Bacteria, Capacitive detection, Simulation, article
Cilt: 269
ISSN: 0924-4247
Sınıflandırma :
18
Remote control of an ultrasonic motor by using a GSM mobile phone
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors And Actuators A-Physical
Yazar(lar) :
E Bekiroglu , N Daldal
Konu :
ultrasonic motor, remote control, GSM, mobile phone
Yıl :
2005
Sensors And Actuators A-Physical
Yayıncı Web Sitesi
Kaydet
In this study, remote control of an ultrasonic motor has been implemented by using a standard GSM mobile phone. To drive the ultrasonic motor a digitally controlled drive system has been designed. Then a tone decoder circuit and microcontroller have been added between output of a mobile phone and the drive system of the motor. This system is flexible to be controlled with both GSM and DTMF based phones. With the developed drive and control system the overall control of the ultrasonic motor has been achieved. The system has been tested for different speed, position and direction conditions successfully. The experimental results verify that the GSM controlled drive system is highly effective, reliable, proper and applicable to achieve remote control of the ultrasonic motor. This study gets novel and important point of view for GSM based remote control applications addition to the control of ultrasonic motors. (c) 2004 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : ultrasonic motor, remote control, GSM, mobile phone, article
Cilt: 120
Sayı: 2
ISSN: 0924-4247
Sınıflandırma :
19
Influence of deposition potentials applied in continuous and pulse waveforms on magnetic properties of electrodeposited nickel-iron films
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors and Actuators A-Physical
Yazar(lar) :
Mürsel Alper , Hakan Köçkar , Hilal Kuru , Turgut Meydan
Konu :
Electrodeposition, Nife Films, Magnetic Anisotropy
Yıl :
2006
Sensors and Actuators A-Physical
Yayıncı Web Sitesi
Kaydet
Köçkar, Hakan (Balıkesir Author) The effect of the various cathode potentials applied in continuous and pulse waveforms on magnetic anisotropy of NiFe alloy films grown on (100) textured polycrystalline copper substrates has been studied. Magnetic measurements obtained by a vibrating sample magnetometer (VSM) showed that the magnetic anisotropy of the films is very sensitive to the cathode potentials and the type of the potentials applied during deposition. It was found that the easy axis of all films is in the film plane. The magnetic findings also indicated that the NiFe films deposited at the cathode potentials of - 1.2 and - 1.5 V applied in the continuous waveforms, but except for the films deposited at the cathode potential of - 1.8 V, are anisotropic, while those produced at the cathode potentials applied in the pulse waveform show an isotropic magnetic behaviour. Utilising the magnetic properties of the films may offer the potential for the development of a new range of stress sensors.
Anahtar Kelimeler : Electrodeposition, Nife Films, Magnetic Anisotropy, article

ISSN: 0924-4247
20
Direction finding of moving ferromagnetic objects inside water by magnetic anomaly
Dergi Makalesi

Dergi Makalesi Open Access
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors and Actuators A-Physical
Yazar(lar) :
Yavuz Ege , Osman Kalender , Sedat Nazlıbilek
Konu :
Magnetic Anomaly, Remore Sensing, Magnetic Measurement, Scanning Systems
Yıl :
2008
Sensors and Actuators A-Physical
Yayıncı Web Sitesi Tam Metin
Kaydet
Ege, Yavuz (Balikesir Author) The remote sensing methods by the use of magnetic anomaly are gaining importance in applications of defense technologies and industrial purposes recently. In this study, it is aimed to determine the remote detection, the variation of characteristic of the voltage in the sensor relative to the motion, the effects of material length, magnetic permeability and direction of motion of the object on this characteristic and to convert them to a useful mathematical expression by using magnetic anomaly of ferromagnetic objects such as submarines moving inside water. For this purpose, first of all. a water tank of 1 m(3) is prepared and approximately a homogeneous magnetic field of 10(-3) T is created within this water tank. Ferromagnetic materials with six different lengths and permeabilities are moved in three different directions relative to the position of the sensor by means of a computer controlled x-y scanner designed for this experiment inside this magnetic field. The magnetic change Caused by this motion at the point where the sensor is positioned is detected as the Output voltage of the sensor. A mathematical expression is formulated taken into account the variations of the sensor output voltage with respect to the length, magnetic permeability and the direction of motion of the material and it is validated by the experimental results. This study clearly shows that the existence and the direction of motions of ferromagnetic objects with different lengths and magnetic permeabilities inside water can be detected with high accuracy. Olimed Ltd. Co.
Anahtar Kelimeler : Magnetic Anomaly, Remore Sensing, Magnetic Measurement, Scanning Systems, article

ISSN: 0924-4247
21
Impedimetric detection of miRNA-34a using graphene oxide modified chemically activated graphite electrodes
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors and Actuators A-Physical
Yazar(lar) :
Congur , Gulsah , Eksin , Ece , Erdema , Arzum
Konu :
miRNA-34a, Graphene oxide (GO), Chemical activation, Pencil graphite electrode (PGE), Electrochemical impedance spectroscopy (EIS)
Yıl :
2018
Sensors and Actuators A-Physical
Yayıncı Web Sitesi
Kaydet
Graphene oxide (GO) modified graphite electrodes were developed for sensitive and selective impedimetric detection of miRNA-34a which is the biomarker of Alzheimers disease and various types of cancer. For this purpose, pencil graphite electrodes (PGEs) were used as recognition platform. First, chemical activation of the surfaces of PGEs was done using covalent agents (CA), then GO modification was performed at the surface of chemically activated disposable PGEs. The results of microscopic and electrochemical characterization of GO-CA-PGEs were represented. The step-by-step hybridization process was implemented for impedimetric detection of miRNA-34a and the experimental conditions were optimized for each modification/immobilization step. Under the optimum conditions, the detection limits for miRNA-34a target were estimated as 1.84 mu g/mL (261.7 nM) in PBS (pH 7.4) and 0.5 mu g/mL (72.5 nM) in diluted FBS:PBS (1:1). The selectivity of GO based impedimetric biosensor was tested against to other miRNAs; miRNA-15a, miRNA-155 and miRNA-660. (C) 2018 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : miRNA-34a, Graphene oxide (GO), Chemical activation, Pencil graphite electrode (PGE), Electrochemical impedance spectroscopy (EIS), article
Cilt: 279
ISSN: 0924-4247
Sınıflandırma :
Kimya %99
Nanokimya %100
22
Reference-plane invariant transmission-reflection method for measurement of constitutive parameters of liquid materials
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors and Actuators, A: Physical
Yazar(lar) :
Bayburt Üniversitesi
Konu :
Liquid materials, Material characterization, Measurement of dielectric, magnetic materials, Microwavemeasurements, Reference-plane invariant, Constitutive parameters, Frequency ranges, Liquid materials, Low-loss liquids, Material characterizations, Measurement cell, Reference-plane invariant, Vertical positions, Characterization, Dielectric materials, Liquids, Magnetic materials, Measurements, Microwave measurement, Scattering parameters, Uncertainty analysis, Parameter estimation, Liquid materials, Material characterization, Measurement of dielectric, magnetic materials, Microwavemeasurements, Reference-plane invariant, Constitutive parameters, Frequency ranges, Liquid materials, Low-loss liquids, Material characterizations, Measurement cell, Reference-plane invariant, Vertical positions, Characterization, Dielectric materials, Liquids, Magnetic materials, Measurements, Microwave measurement, Scattering parameters, Uncertainty analysis, Parameter estimation
Yıl :
2013
Sensors and Actuators, A: Physical
Yayıncı Web Sitesi Piri Tam Metin Bulucu
Kaydet
We propose a new transmission-reflection method for measuring constitutive parameters of liquid samples inside an asymmetric measurement cell (a sample over a low-loss holder in vertical position inside an empty waveguide section). We derived reference-plane invariant expressions for constitutive parameters measurement of liquid samples from reference-plane dependent scattering parameters. In addition, we also applied a simple approach for unique determination of transformation factor and reference-plane distances. After, we also investigated how the performance of the proposed method could be improved by performing a differential uncertainty analysis. From this analysis, we found the following key results: (a) the accuracy of the proposed method could be enhanced for low-loss liquid samples by using thicker samples, and (b) the effect of constitutive parameters and the length of the (low-loss) sample holder on constitutive parameters measurements of liquid samples by the proposed method is a key parameter in increasing the accuracy of the measurements. Finally, we performed constitutive parameter measurements of distilled water and methanol to validate the proposed method and compared the proposed method with similar methods in the literature. From the measurements, we note that our method is especially useful for liquid sample measurements when the reference-plane transformation factors are not known a priori and/or if the measurements are carried out over a high frequency range. © 2013 Elsevier B.V.
DOI : 10.1016/j.sna.2013.09.007
Anahtar Kelimeler : Liquid materials, Material characterization, Measurement of dielectric and magnetic materials, Microwavemeasurements, Reference-plane invariant, Constitutive parameters, Frequency ranges, Liquid materials, Low-loss liquids, Material characterizations, Measurement cell, Reference-plane invariant, Vertical positions, Characterization, Dielectric materials, Liquids, Magnetic materials, Measurements, Microwave measurement, Scattering parameters, Uncertainty analysis, Parameter estimation, Liquid materials, Material characterization, Measurement of dielectric and magnetic materials, Microwavemeasurements, Reference-plane invariant, Constitutive parameters, Frequency ranges, Liquid materials, Low-loss liquids, Material characterizations, Measurement cell, Reference-plane invariant, Vertical positions, Characterization, Dielectric materials, Liquids, Magnetic materials, Measurements, Microwave measurement, Scattering parameters, Uncertainty analysis, Parameter estimation, article
Cilt: 203
ISSN: 0924-4247
Sınıflandırma :
23
Photoresponsive n-channel organic field effect transistor based on naphthalene bis-benzimidazole with divinyltetramethyl disiloxane-bis (benzo-cyclobutene) gate insulator
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors and Actuators A-Physical
Yazar(lar) :
Tozlu Cem , Erten-Ela Sule , Icli Siddik
Konu :
photOFET, Photosensitivity, Photoresponsivity, Naphthalene bis-benzimidazole
Yıl :
2010
Sensors and Actuators A-Physical
Yayıncı Web Sitesi
Kaydet
A novel photoresponsive organic field effect transistor (photOFET) based on naphthalene bis-benzimidazole (NBBI) by employing a transparent divinyltetramethyl disiloxane-bi (BCB) as dielectric is presented. The optical properties of naphthalene tetracarboxylic diimide (NTCDI) were changed by substitution of imidazole groups, in order to improve amplification of fabricated transistor by light in the visible region. The electrical characteristics of photOFET showed n-channel properties under illumination and dark. The NBBI based organic field effect transistor exhibited saturated electron mobility of 6 x 10(-3) cm(2)/V s with threshold voltage of 7.2 V. The photogenerated charge carriers strongly influence the drain-source current in comparison to dark condition. The photosensitivity and photoresponsivity of device are found to be 93.4 mA/W and 14.3 mA/W, respectively, at off-state of device under white light at AM 1.5 condition. (C) 2010 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : photOFET, Photosensitivity, Photoresponsivity, Naphthalene bis-benzimidazole, article
Cilt: 161
Sayı: 01.Feb
ISSN: 0924-4247
Sınıflandırma :
24
Integration of through-wafer interconnects with a two-dimensional cantilever array
Dergi Makalesi

Dergi Makalesi Open Access
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors and Actuators A: Physical
Yazar(lar) :
E. M. Chow , H. T. Soh , H. C. Lee , J. D. Adams , S. C. Minne , G. G. Yaralioglu , Abdullah Atalar , C. F. Quate , T. W. Kenny
Konu :
Sensor Array, Scanning probe microscope, Through-wafer electrical ınterconnect, Piezoresistive silicon cantilever
Yıl :
2000
Sensors and Actuators A: Physical
Yayıncı Web Sitesi Tam Metin
Kaydet
High-density through-wafer interconnects are incorporated in a two-dimensional (2D) micromachined cantilever array. The design addresses alignment and density issues associated with 2D arrays. Each cantilever has piezoresistive deflection sensors and high-aspect ratio silicon tips. The fabrication process and array operation are described. The integration of cantilevers, tips, and interconnects enables operation of a high-density 2D scanning probe array over large areas.
DOI : 10.1016/S0924-4247(99)00381-7
Anahtar Kelimeler : Sensor Array, Scanning probe microscope, Through-wafer electrical ınterconnect, Piezoresistive silicon cantilever, Article
Cilt: 83
Sayı: 1-3
ISSN: 0924-4247
Sayfa: 118-123
Sınıflandırma :
25
Non-destructive crack detection by capturing local flux leakage field
Dergi Makalesi

Dergi Makalesi Open Access
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors and Actuators A-Physical
Yazar(lar) :
Mustafa Göktepe
Konu :
Non-Destructive, Crack Detection, Crack, Leakage Field, Sensor, Transducer
Yıl :
2001
Sensors and Actuators A-Physical
Yayıncı Web Sitesi Tam Metin
Kaydet
The crack detection in the industrial machine parts is very important. The non-destructive crack detection and evaluation of the these cracks are highly desirable from the viewpoint of safe and economic operation of installed facilities such as industrial factories and power plants. A crack induces local damages in the magnetic flux path in a ferromagnetic material and any change in crack area results in change in the distribution of magnetic flux in the material. In this paper, variation of the magnetic flux distribution in locally magnetised ferromagnetic materials which has discontinuity as a crack, is studied.
Anahtar Kelimeler : Non-Destructive, Crack Detection, Crack, Leakage Field, Sensor, Transducer, article

ISSN: 0924-4247
26
Signal performance of DC-SQUIDs with respect to YBCO thin film deposition rate
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors and Actuators A-Physical
Yazar(lar) :
Avci I. , Algul B. P. , Akram R. , Bozbey A. , Tepe M. , Abukay D.
Konu :
YBCO thin films, Deposition rate, Josephson junctions, DC-SQUIDs
Yıl :
2009
Sensors and Actuators A-Physical
Yayıncı Web Sitesi
Kaydet
The signal performances of YBa2Cu3O7-delta (YBCO) direct current superconducting quantum interference devices (DC-SQUIDs) have been investigated as a function of the thin film structure affected by the growth process. YBCO thin films of 200 nm thicknesses were deposited by DC magnetron sputtering using different deposition rates between 1.0 nm/min and 2.0 nm/min onto 24 degrees bicrystal SrTiO3 (STO) substrates. The thin film samples were subsequently analyzed by XRD and AFM in order to determine their crystalline structures and surface morphologies respectively. The 67 pH directly coupled DC-SQUIDs with 4 mu m-wide bicrystal Josephson junctions were fabricated, and characterized with respect to their device performances. The variations in the critical current (l(c)), the voltage modulation depth (Delta V) and the noise performance of DC-SQUIDs were reported. The SQUIDs having relatively low deposition rate of 1.0 nm/min was observed to have larger voltage modulation depth as well as higher critical current than that of the samples having larger rate of 2.0 nm/min. The better noise performances were observed as the film deposition rate decreases. The results were associated with the thin film structure and the SQUID characteristics. (C) 2009 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : YBCO thin films, Deposition rate, Josephson junctions, DC-SQUIDs, article
Cilt: 153
Sayı: 1
ISSN: 0924-4247
Sınıflandırma :
27
Precision density and viscosity measurement using two cantilevers with different widths
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors and Actuators A: Physical
Yazar(lar) :
O. Cakmak , E. Ermek , N. Kilinc , Göksen Göksenin Yaralıoğlu , H. Urey
Konu :
Cantilever, Microcantilever, Viscosity, Density, MEM
Yıl :
2015
Sensors and Actuators A: Physical
Yayıncı Web Sitesi
Kaydet
We introduce a novel method for fast measurement of liquid viscosity and density using two cantilevers with different geometries. Our method can be used for real-time monitoring in lab on chip systems and offer high accuracy for a large range of densities and viscosities. The measurement principle is based on tracking the oscillation frequencies of two cantilevers with a phase-locked loop (PLL) and comparing with reference measurements with a known fluid. A set of equations and a simple algorithm is developed to relate the density and the viscosity to the frequency shifts of the cantilevers. We found that the effect of the density and the viscosity can be well separated if cantilevers have different widths. In the experiments, two Nickel microcantilevers (widths 25 μm and 100 μm, length: 200 μm, thickness: 1.75 μm) were fully immersed in the liquid and the temperature was controlled. The actuation was using an external electro-coil and the oscillations were monitored using laser Doppler vibrometer. Thus, electrical connections to the cantilevers are not required, enabling measurements also in conductive liquids. The PLL is used to set the phase difference to 90° between the actuator and the sensor. Calibration measurements were performed using glycerol and ethylene glycol solutions with known densities and viscosities. The measurement error with the new method was lower than 3% in density in the range 995–1150 kg/m3 and 4.6% in viscosity in the range 0.935–4 mPa.s. Based on the signal-to-noise ratio, the minimum detectable difference in the viscosity is 1 μPa.s and the density is 0.18 kg/m3. Further improvements in the range and the accuracy are possible using 3 or more cantilevers with different geometries.
Anahtar Kelimeler : Article

ISSN: 0924-4247
Sınıflandırma :
28
Liquid refractometric sensors based on optical fiber resonators
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Sensors and Actuators, A: Physical
Yazar(lar) :
M. Eryürek , Y. Karadag , M. Ghafoor , N. Bavili , K. Cicek , A. Kiraz
Konu :
Ethanol, Ethylene glycol, Liquid refractometry, Optical fiber resonator, Optical sensor, Tapered fiber, WGM
Yıl :
2017
Sensors and Actuators, A: Physical
Yayıncı Web Sitesi
Kaydet
A robust, easy-to-fabricate, and sensitive liquid refractometric sensor utilizing optical fiber resonators (OFRs) obtained by simple stripping and cleaning of conventional optical fibers is presented. The sensing scheme is based on recording the spectral changes of the whispering gallery modes (WGMs) observed in the transmission spectrum of an OFR excited with a tunable laser coupled to the OFR through an independent tapered optical fiber. The demonstrated sensor device is tested and fully characterized with water solutions of ethanol and ethylene glycol (EG). Good agreements are obtained with theoretical predictions for both ethanol and EG cases when TE and TM polarized WGMs are considered. The limit of detection of the demonstrated sensor is determined to be between 2.7 and 4.7 × 10-5 refractive index unit (RIU) comparable to the state-of-the-art when precise temperature control of the sample chamber is missing. © 2017 Elsevier B.V.
Anahtar Kelimeler : Ethanol, Ethylene glycol, Liquid refractometry, Optical fiber resonator, Optical sensor, Tapered fiber, WGM, article
Cilt: 265
ISSN: 0924-4247
Sınıflandırma :

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