Effect of glucose (C6H12O6) addition on piezoelectric properties of sensor
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https://www.eduzhai.net American Journal of Biomedical En gineer in g 2012, 2(6): 287-292 DOI: 10.5923/j.ajbe.20120206.08 Effect of Glucose(C6H12O6) Addition on PiezoelectricProperties for Sensor Application Ali Jasim Mohamme d Al-Jabiry*, Marwa Abdul Muhsien Hassan Department of physic, College of Science, Al-M ustansiriyah University, Baghdad, Iraq Abstract Effect of g lucose addition on piezoelectric sensing of water solution has been investigated with different percentages (0, 0.05, 0.1 and 0.15) wt. %. Sensing signals (piezoelectric) characterized and achieved by using transducer which transmits a mechanical waves towards the glucose solution cell, and then the receptor received the attenuated signals. The range of operating frequencies was (10 kHz - 50M Hz), the results of measurement which included record ing the resonance frequencies (in the first order) for all prepared samples. The results showed that the resonance frequency shifted to the higher values (fro m 5M Hz to 35M Hz) fo r glucose concentrations (from 0 to 1 wt. %) of water solution. Also the damping coefficient decreased (fro m 1.19 to 1.02) for the same range of g lucose concentrations. Keywords Glucose, Piezoelectric Propert ies, Resonance Frequency, Damp ing Coefficient, Water So lution 1. Introduction In 1880, Jacques and Pierre Curie discovered an unusual characteristic of certain crystalline minerals, when subjected to a mechanical force, the crystals became electrically polarized. Tension and compression generated voltages of opposite polarity, and in proportion to the applied force. Subsequently, the converse of this relat ionship was confirmed : if one of these voltage-generating crystals was exposed to an electric field it lengthened or shortened according to the polarity of the field, and in proportion to the strength of the field. These behaviours were labelled the piezoelectric effect and the inverse piezoelectric effect, respectively, fro m the Greek word piezein, mean ing to press or squeeze as shown in Figure (1). Piezoelectric behaviour in general can be man ifested in two ways ‘direct’ piezoelectric effect and ‘converse’ piezoelectric effect. Direct piezoelectric effect occurs when a piezoelectric material becomes electrically charged when subjected to a mechanica l stress. These devices can be used to detect strain, movement, force, pressure or vibration by developing appropriate electrical responses, as in the case of force and acoustic or ultrasonic sensors. Conve rs e pie zoe lect ric e f fect oc curs when the piezoelectric material becomes strained when placed in an electric field. This property can be used to generate strain, * Corresponding author: email@example.com (Marwa Abdul Muhsien Hassan) Published online at https://www.eduzhai.net Copyright © 2012 Scientific & Academic Publishing. All Rights Reserved movement, force, pressure or vibrat ion through the application of suitable electric field. The piezoelectric effect is used in sensing applications, such as in force or displacement sensors. The inverse piezoelectric effect is used in actuation applications, such as in motors and devices that precisely control positioning, and in generating sonic and ultrasonic signals.The piezoelectric effect occurs when the charge balance within the crystal lattice of a materia l is disturbed. When there is no applied stress on the material, the positive and negative charges are evenly distributed so there is no potential difference. When the lattice is changed slightly, the charge imbalance creates a potential difference, often as high as several thousand volts. However, the current is ext remely small and only causes a small electric shock. The converse piezoelectric effect occurs when the electrostatic field created by an electrical current cause the atoms in the materia l to move slightly, whe re the materia l is heated under the application of a strong electric field. The heat allows the mo lecules to move more freely and the electric field forces all of the dipoles in the crystal to line up and face in nearly the same direction as shown in Figure (2). 1.1. Piezoelectric Characteristics Certain crystals possess a permanent electrical dipole because their canters of positive and negative charges are not at the canters of the unit cells. These unit cells are polarized. Many materials change their dimensions in an electric field because the negative charges are pulled towards the positive electrode, and the positive charges are pulled towards the negative electrode as shown in Figure (3). 288 Ali Jasim M ohammed Al-Jabiry et al.: Effect of Glucose(C6H12O6) Addition on Piezoelectric Properties for Sensor Application Figure 1. Piezoelectric Phenomena Figure 2. Polarization of material to generate piezoelectric effect Figure 3. The charges pulled toward the opposite electrodes The pulling of the charges will increase the dipole length (d), this also increases the dipole mo ment (Qd), and the polarization (p), since the latter is the total of the dipole mo ment (ΣQd) per unit volu me (V): ???????? = ∑???????????????? /???????? (1) This sequence of effects provides the means of changing mechanica l energy into electrica l energy and vice versa. Because a piezoelectric is anisotropic, physical constants relate to both the direction of the applied mechanical or electric force and the directions perpendicular to the applied force. Consequently, each constant generally has two subscripts that indicate the directions of the t wo related quantities, such as stress and strain for elasticity. The direction of positive polarization usually is made to coincide with the Z-axis of a rectangular system of X, Y, and Z axis Figure (4). Direction X, Y, or Z is represented by the subscript 1, 2, or 3, respectively, and shear about one of this a xis is represented by the subscript 4, 5, or 6, respectively. 1.2. Piezoelectric Coefficients Figure 4. Direction of force affecting a piezoelectric element Figure 5. The mechanism of piezoelectric application Piezoelectric transducers are widely used to generate ultrasonic waves in solids and also to detect such mechanical waves as shown in Figure (5) where the transducer on left is excited fro m an AC source and vibrates mechanically, these vibrations are coupled to the solid and generate elastic wave, when the waves reach the other end, they mechanically American Journal of Biomedical Engineer ing 2012, 2(6): 287-292 289 vibrate the transducer on the right, which convert the vibration to an electrica l signal. 1.3. Characteristic Frequency ( fe ) The characteristic (fundamental) frequency (fe) will be considered as the oscillation of the particles on both surfaces of the block material of the thin film, when the two electrodes are contacted the particle swings outwards and inwards, while the central plate re ma ins constantly at rest. Hence a standing wave will be produced, and the characteristic frequency is related to the plate thickness as in relation: ???????? = ????????/2 = ???????????????? /2???????????????? (2) where ????????= The plate thickness, ????????????????= The velocity of sound. (tˊ =1/ f), (f) is the frequency, (ω = 2πf), (τ) is the resonance time. 1.5. Resonance Frequency (fo) When an unrestrained piezoelectric element is exposed to a high frequency alternating electric field, impedance minimu m, the planar or radial resonance frequency, coincides with the series resonance frequency, fs. At higher frequencies resonance, another impedance minimu m, the axial resonance frequency, is encountered. This frequency is characterized by the output amplitude as shown in Figure (7). 1.4. Damping Coefficient (δ) Damping is a material property, wh ich is very important to vibration control in engineering. The nu merical results of vibration and acoustical analysis are very sensitive to this parameter. Fo r the mechanical damping treat ment of structure is necessary to consider three parameters: damping; mass, and stiffness. These three parameters are needed to design and optimize piezoelectric transducers by using numerical modelling since all of them have some effect in piezoelectric transducer dynamic response. In addition, most part of systems that dissipate energy by vibration is non-linear. Therefo re, it is necessary to develop models of ideal damp ing with suitable appro ximation. The several types of damping are: 1) Viscous damping, due to energy dissipation; 2) Structural damp ing, due to the material properties; 3) Friction damp ing, due to mechanical sliding between s u rfaces . The damp ing coefficient (δ) is the factor that the amp litude will be decreased fro m one oscillat ion to the next oscillation according to it as in the Figure (6), and the damped amplitude is given by the relation: Figure 7. Resonance curve of forced oscillation Up to the resonance frequency (fo) it increases to a maximu m, where the value depends on the damping coeffic ient. 1.6. Quality Factor (Q) To achieve ultra-h igh resonator sensitivity, high quality factor (Q-factor) is most desirable in resonator design and fabrication. Under atmospheric pressure, air damping is the predominant mechanism for energy dissipation . Air damping becomes less effective if p ressure goes down, and then it is easier to identify the effects of other energy dissipation mechanisms. The Q can be defined as the ratio of the amplitude at resonance frequency to the static th ickn es s : Q= ΔXfo / ΔXstat (4) Also it is connected to the damping coefficient (δ) as in relation: Q=π / lnδ (5) The higher order modes achieve higher frequencies and the increase of resonance frequency will decrease the Q-factor. 1.7. Bandwi dth (B) The bandwidth (B) is linked with, which represents 70% of the maximu m value of the resonance frequency, normally Figure 6. Decay of oscillation with damping coefficient δ it is calcu lated fro m the resonance curve, and then the characteristic frequency can be calculated by using the h(t) = Ao exp(−t/τ) sin (ω tˊ) (3) relation: where: B = fe /???????? (6) (Ao ) is the amp litude at resonance, Where: 290 Ali Jasim M ohammed Al-Jabiry et al.: Effect of Glucose(C6H12O6) Addition on Piezoelectric Properties for Sensor Application fe : the characteristic frequency. Q: the quality factor. 2. Experimental Work addition, this varied can be due to a number of reasons, such as humidity, at mospheric pressure and mechanical loading. The effect of glucose addition on resonance frequency can be seen in Figure (10). The material used in this paper is glucose(C6H12O6) addition on water solution. The electronic balanced of accuracy 10-4 have been used to obtain a weight amount of glucose(C6H12O6) powder. The weight percentages of glucose(C6H12O6)powder are (0, 0.05, 0.1 and 0.15) wt. %. The effect of glucose(C6H12O6)addition on piezoelectric sensing of water solution was measured. The setting used in this paper include a standard two piezo-crystals(Model number: 3B12+9.0EAWC, Type: Piezoelectric Ceramics, Material: Piezoceramics, Metal type: Brass, Electrode form: (Thin) Diode, Connection terminal: Soldier wire or not, Parameter value: (D=12mm, T=0.15mm and f=9 kHz))located tightly on the copper foil as a diaphragm shown in Figure (8). Figure 10. The resonance frequency at different glucose addition The damp ing coefficient (δD)can be calculated using the relation (3), and it can be drawn for samples with different glucose addition as shown in Figure (11) (a, b, c and d). The damp ing coefficient (δD)of the water solution at different glucose addition were carried out fro m the graph and using the relation: δD = A1/A2 (10) Figure 8. Image of piezo-crystal used in this work The pressure (mechanical) signal was produced on the diaphragm using a function generator (B+K precision 3020) supplied an electrical signal of frequency in the range(1–100000) KHz. The pressure signal can be sensed by water solution and analyzed with the oscilloscope (KENWOOD 20 M Hz CS – 1021). h (t) 200 150 100 50 0 -50 0 -100 -150 -200 -250 -300 A1 δ=1.04 a A2 0.0002 0.0004 0.0006 0.0008 0.001 Time (sec) 3. Result and Discussion Amplitude (Ao) 1000 900 800 700 600 500 400 300 200 100 0 Water 0.05% 0.10% 0 10000 20000 30000 40000 50000 60000 Frequency (kHZ) Figure 9. The resonance frequency of water solution at different glucose (C6H12O6)addition (water, 0.05%, 0.1% and 0.15%) The resonance frequency can be determined by measuring the output voltage as a function of frequency as shown in Figure (9), we can observed that the resonance value varied fro m 10 kHz to 50 M Hz, by change the glucose (C6H12O6) h (t) h (t) 500 400 300 200 100 0 -100 0 -200 -300 400 200 0 0 -200 δ=1.19 A1 A2 0.0002 0.0004 0.0006 Time (sec) A1 A2 δ=1.08 0.0002 0.0004 0.0006 0.0008 0.0008 b 0.001 c 0.001 -400 -600 Time (sec) American Journal of Biomedical Engineer ing 2012, 2(6): 287-292 291 300 200 A1 δ=1.02 d A2 100 h (t) 0 -100 0 0.0002 0.0004 0.0006 0.0008 0.001 -200 -300 -400 -500 Time (sec) Figure 11. The relation between the time of resonance andthe damping for water solution at different glucose addition: a- water, b-0.05%, c-0.1% and d-0.15% 10 MHz 50 MHz Figure 13. The supplied frequencies (upper) and the sensing frequencies (lower) by the water solution at 0.05 wt.% glucose addition The shifting between the transmitted signal and that of water solution at different glucose addition are shown in Figures (12), (13), (14) and (15), it is clearly that the large shifting vanish with increasing the source frequency. The characteristic of frequency can be calculated by using the relation (6) depending on the band width and the quality factor and the result tabled in table (1). 200 kHz 500 kHz 200 kHz 500 kHz 10 MHz 50 MHz Figure 14. The supplied frequencies (upper) and the sensing frequencies (lower) by the water solution at 0.1 wt.%glucose addition 10 MHz 50 MHz Figure 12. The supplied frequencies (upper) and the sensing frequencies (lower) by the water solution 200 kHz 500 kHz 200 kHz 500 kHz 10 MHz 50 MHz Figure 15. The supplied frequencies (upper) and the sensing frequencies (lower) by the water solution at 0.15 wt.% glucose addition 292 Ali Jasim M ohammed Al-Jabiry et al.: Effect of Glucose(C6H12O6) Addition on Piezoelectric Properties for Sensor Application glucose addit ion 0% 0.05% 0.1% 0.15% fo (kHz) 4500 9000 30000 20000 Table (1). The result of piezoelectric properties Band width (kHz) B 355.62 514.69 653.97 586.81 Damping coeff. Δ 1.04 1.19 1.08 1.02 Quality factor Q 76.91 17.33 38.18 118.99 Surface Acoustic wave Velocity ×103 (m/s) 474.136 154.613 432.813 1210.39 Ch aract erist ic frequency fe (kHz) 27354.21 8920.141 24969.95 69829.86 The acoustic is travelling through the water solution with velocity depending on the material addition of the water solution and on the characteristic frequency, and then the velocity could be evaluated using the relation (2). The velocity values were recorded as a function of glucose addition as shown in Figure (16). percentages (0, 0.05, 0.1 and 0.15) wt. %. The results showed that the resonance frequency shifted to the higher values (fro m 5MHz to 35MHz) for g lucose concentrations (from 0 to 1 wt. %) of water solution. Also the damping coefficient decreased (fro m 1.19 to 1.02) for the same range of glucose co n centratio n s . Quality factor (Q) Figure 16. Ultrasound velocity as a function of glucose addition of water so lut ion The quality factor was esteemed be using the relation (5), as we observed the value of the quality decrease when the resonance frequency increase, the result was listed in table (1). The effect of glucose addition can be seen in Figure(17). 140 120 100 80 60 40 20 0 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 Glucose addition wt. % Figure 17. Effect of glucose addition on the quality factor 4. Conclusions In this paper, effect of glucose addition on piezoelectric sensing of water solution has been investigated with different REFERENCES  L. H. Van Vlack, "Elements of M aterial , Science and Engineering, fifth edition , Addison – Wesley Publishing Company, 355, 1987.  A. J. M ohammad , " Studying the Effect of M olarity on the Physical and Sensing Properties of Zinc Oxide Thin Films Prepared by Spray Pyrolysis Technique", Ph.D Thesis , University of Technology , Baghdad , Iraq , 2007.  S.O.Kasor "Principles of Electronic M aterials and Devices", second edition M c Grow Hill, chapter 7, 2002.  J.Lu, " High Quality Factor Silicon Cantilever Driven by PZT Actuator for Resonant Based M ass Detection", 2008.  J. Krautkrämer and Herbert Krautkrämer,"Ultrasonic Testing of M aterials" , Springer – Verlag, 1969 .  ABCM Symposium Series in M echatronics, 1, 271-279, 2004.  S. I. Baskalov , "Signals and Circuits , Problem Solving Guide" , M ir Publishing , M oscow , 1990 .  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