International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:14 No:05 59

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1 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:14 No:05 59 Development of Low Cost Microwave Detection System for Salinity and Sugar Detection E.M. Cheng*,1, M. Fareq 2, Shahriman A. B. 1, Mohd Afendi 1, Zulkarnay Z. 1, S. F. Khor 2, Liyana Z. 3, Nashrul Fazli M. N. 1, W. H. Tan 1, N. S. M. Noorpi 2, N. M. Mukhtar 2 and M. Othman 2 1 School of Mechatronic Engineering, Universiti Malaysia Perlis, UniMAP, Arau, Perlis, Malaysia emcheng@unimap.edu.my* shahriman@unimap.edu.my afendirojan@unimap.edu.my zulkarnay@unimap.edu.my nashrul@unimap.edu.my whtan@unimap.edu.my 2 School of Electrical System Engineering, Universiti Malaysia Perlis, UniMAP, Arau, Perlis, Malaysia mfareq@unimap.edu.my sfkhor@unimap.edu.my nursabrina@unimap.edu.my nurhakimah@unimap.edu.my mardianaliza@unimap.edu.my 3 School of Computer and Communication Engineering, Universiti Malaysia Perlis, UniMAP, Arau, Perlis, Malaysia liyanazahid@yahoo.com *Corresponding author:e.m. Cheng Abstract This work is proposed to develop a low cost measurement system to check the salinity and sugar content of food. A Mini-Circuits ZX voltage controlled oscillator (VCO), Mini-Circuits ZGDC10-362HP+ high power directional coupler, Mini Circuits PWR-6GHS+ USB Smart power sensor and open-ended coaxial probe made of semi-rigid coaxial cable RG402/U are used. The main idea for this work is based on electromagnetic reflection due to the impedance mismatch. In order to verify efficiency and accuracy of this developed detection system, comparison with measured result from P-series network analyzer (PNA) is conducted. The measured reflection coefficient from developed system was discussed among Agilent 85052D High-Temperature probe, RG405/U and RG402/U openended coaxial probe. Index Term Salinity; Sugar; open-ended coaxial probe, reflection coefficient; microwave detection system 1. INTRODUCTION Sodium chloride is one type of salt, with molecular formula as NaCl. Salt is a vital to supply essential component for the human body [1], e.g. salt help to maintain osmosis equilibrium in cells to maintain and is used to transmit information in our nerves and muscles. Salt is also added to food usually for purpose of seasoning, preservatives and texture aid. However, excessive intake of salt for long term will lead to high blood pressure, stroke, edema, kidney failure and cardiovascular diseases. According to the United States Department of Health and Human Services, a man should consume not more than mg of salt ( mg) per day depending on age. In addition, the nutrition labels of salt on food packing which is administered by Food Standards Agency [2] regulate the level of salt intake by human body. Although the Food Standards Agency has regulated the quantity of the salt mandatory in the food industry with act, some industry runner may ignore the act by applying excessive salt to enhance flavor of their food product for the sake of sales. Sugar usually refers to all carbohydrates of the general formula C n (H 2 O) n in a chemical term. Sugar composed of carbon, hydrogen and oxygen. Sucrose is the most common sugar which is a crystalline tabletop and industrial sweetener used in foods and beverages. Apart from salt, sugar is also a flavor-enhancer. Sugar used to interacts with molecules of protein or starch during baking and cooking process. Excessive sugar intake can cause drowsiness, decreased activity, hyperactivity, anxiety, difficulty concentrating, and crankiness. Hence, American Heart Association advised that 30g of daily sugar intake for women and a man should not consume more than 45g. For diabetic patient, advised amount of sugar intake is 20g per day for women patient and 30g per day for men patient [3]. Hence, a low cost and efficient method is proposed in this work as liquid compound chromatography to monitor the salt and sugar intake by a person or applied by food industry. There are many methods are reported to be liquid compound chromatography. The estimation of compound in liquid with High-Performance Liquid Chromatography (HPLC) by means of Ultraviolet-Visible (UV-VIS) has been widely investigated over the recent years [4] [7]. As electric properties of liquid depend on their composition, it is obvious that the parameters either polar moment, ionic conductivity, optical resonance or etc significantly inspired researchers to explore in liquid compound analysis.

2 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:14 No: LITERATURE REVIEW The earliest reports of compound analyzer were published since twentieth century. Moisture content in grain was determined by the concept of permittivity measurement based on DC electrical resistance. It was reported by Knipper on year 1953 [8]. The first moisture meter was invented in the former Union of Soviet Socialist Republics (U.S.S.R.) for barley and wheat moisture measurement. Dunlap and Makower (1945) [9] measured the dielectric properties of carrots from 18 khz to 5 MHz and reported that the dielectric constant and conductivity of carrots are relatively depend on moisture content, frequency, temperature, density, and particle size. In addition, Kundra et al. (1992) [10] studied effects of dissolved salts in milk on dielectric properties. The salinity and frequency effect on the dielectric constant was proved by the Gadani et al. (2006) [11]. Their work indicated that dielectric constant decreases when concentration of saline water increase from 5000 to 35000ppm (parts per million). Meanwhile, loss factor of saline water decreases when frequency increases. A salinometer is developed by Thomas M. Dauphi et al. (1983) [12] based on a direct determination of the conductivity ratio of sample to standard seawater in dual cell. Then, a research was conducted to measure the complex dielectric constant of pure and sea water using satellite [13]. 3. Methods and Materials 3.1 Sample Preparation In this work, the samples were prepared in liquid state. During the sample preparation, pure NaCl and sugar are dissolved into distilled water separately to have several solutions with different percentage of amount of salt and sugar. In order to ensure the complete dissolution in water, the sample must be prepared in advance before measurement is conducted. 3.2 System Development /Assembly Figure 1 illustrate the developed low cost detection system for sugar and salt content in water by assembling microwave source, directional coupler, power sensor and open-ended coaxial probe. The microwave source of this developed system is Mini-Circuits ZX S+ Voltage Controlled Oscillator (VCO) as shown in Figure 2. According to its datasheet, desired frequency of microwave signal will be generated based on the requirement of user. However, RF Voltage controlled oscillator Output of VCO is connected to input port of ZGDC10-362HP+ high power directional coupler as shown in Figure 3. Output port of directional coupler will be connected to probes, i.e. Agilent 85052D High-Temperature probe, RG405/U or RG402/U semi-rigid coaxial probe. An only coupling port is connected to PWR-6GHS+ USB Smart power sensor (Figure 4). The coupling output will receive coupled reflected power depending on coupling coefficient of directional coupler. Directional coupler is mainly is used to obtain the power level of reflected signal without interrupting the main power flow in the system. PWR-SEN-6G+ USB power sensor are connected to coupling port of directional coupler. The coupled reflected signal will be converted by power sensor to be electrical power and its reading will be displayed on the GUI Measurement Application Software built-in (Figure 2) using laptop. Fig. 1. Overview of the developed detection System 3.3 Reflection measurement USB Power Sensor Directional Coupler A precautious measure during reflection and dielectric measurement must be conducted before reading was taken (Figure 5), i.e. any air bubble must be avoided at aperture of the probe. The air bubble will cause unfavorable reading obtained. Fig. 2. Mini-Circuits ZX S+ Voltage Controlled Oscillator

3 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:14 No:05 61 There were 2 types of probe used in this work, i.e. Agilent 85052D High-Temperature dielectric probe and fabricated open-ended coaxial probes made of RG402/U and RG405/U semi-rigid open-ended coaxial cable, respectively. For Agilent product of Agilent Technologies. High-Temperature dielectric probe with glass-filled has radii a = 0.33 mm and b = 1.5 mm. The further detail of specification can be referred to technical report [14]. Fig. 5. Reading is displayed in GUI Measurement Application Software (a) Fig. 3. Mini-Circuits ZGDC10-362HP+ high power directional coupler (b) Fig. 7. (a) RG402/U and RG405/U semi-rigid open-ended coaxial probe and (b) its configuration For the open-ended coaxial probe made of RG402/U with PTFE-filled, the outer radii of the inner conductor, a is mm. Meanwhile, inner radii of the outer conductor, b is 1.49 mm. In addition, RG405/U with PTFE-filled has a = mm and b = mm. Both RG405/U and RG402/U were connected to 3.5 mm SMA male connector, which has length of 3 mm with a = 0.65 mm and b = 2.05 mm to fabricate semi-rigid coaxial probes for reflection measurement. The configuration of RG4055/U and RG402/U semi rigid coaxial sensor/probe are illustrated in Figure 7. Fig. 4. Mini Circuits PWR-6GHS+ USB Smart power sensor Fig. 6. Agilent 85052D High-Temperature dielectric probe D High-Temperature dielectric probe as shown in Figure 6, it is an high accuracy of dielectric probe which is 4. RESULTS AND DISCUSSIONS 4.1 Salinity measurement Figure 8 and 9 illustrated results of dielectric measurement using Agilent 85052D High-Temperature probe in conjunction with P-series Network Analyzer (PNA). Figure 4 indicates that the dielectric constant of all saline with different percentage of salt content in solution decreases when frequency increase from 200MHz to 20GHz. The delay of response to the change of applied field causes friction and heat. The dissipation of heat energy is described by loss factor. The dissolved salts are presented in positive and negative ions and oscillate in accordance to the time varying electric field. Polarization occurs in such a way to store energy. When the frequency increases, the saline water molecules lose the response to applied field at high frequency as illustrated by Figure 9. As a result, energy storage declined and the rotational losses increased. At these frequencies the mass of the ions prevents them from responding to the variation of

4 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:14 No:05 62 electric field. This measured result is proved by the Debye theory and also described by Hallikainen et al. (1985) [15]. Fig. 8. The variation of dielectric constant with frequency decreases its mobility. The central ion oscillates in the oscillating electric field and the ion atmosphere has less time to reach full relaxation. As a result, it can be noticed that dielectric constant and loss factor decrease when frequency increases. For the issue of variation of both dielectric constant and loss factor with percentage of salt in water, it can be observed that dielectric constant decreases when percentage of salt (concentration) increases. In contrary, loss factor increases with percentage of salt. The more concentrated the solution, the closer these both positive and negative ions. It leads to the greater retardation force, thus the greater the resistance experienced by the ion. Therefore, it causes the decrement of dielectric constant and increment of loss factor when percentage of salt content in water increases as illustrated in Figure 10 and 11. For the lower frequency, i.e GHz, it shows higher dielectric constant and loss factor comparing with other higher frequencies. It is consistent with the Figure 4 and 5. The dielectric constant, loss factor and reflection coefficient remain constant beyond 25% of salt content in solution. It is due to the attainment of state of saturation occurred in solution. Therefore, the discussion about the results for salt content in solution beyond 25% was omitted. In Figure 12, it is shown that reflection coefficient, Г increase with frequency for all percentage of salt content in solution. It can be explained by the dielectric properties of electrolytic solution. Dielectric properties which are function of frequency determine electrical impedance of solution. The decrement of dielectric constant and loss factor due to the increment of frequency as shown in Figure 8 and 9 cause the increment of reflection coefficient with frequency as shown in Figure 13. This behavior can be explained by equations [17]: Fig. 9. The variation of loss factor with frequency for different percentage of salt in solution where 1 j Z0 0CT (1) 1 j Z C C T ( ' j ") C0 C f 0 0 T (2) Figure 9 show that loss factor of saline water decreases when frequency increases. The loss factor decreases steeply from 1GHz to 4GHz and then tends to be constant beyond 4 GHz. According to the Debye-Falkenhagen theory [16], the variation of loss factor with respect to frequency can be explained as it is due to the frequency dependence of the ionic conductivity in an electrolyte solution, e.g. solution contain ionic substance. At high frequency, the ionic conductivity of electrolyte solution declines due to dynamic effect of relaxation of an ions atmosphere on the motion of an ion. The ionic atmosphere lags causes ion moving in an electrolyte solution to experience retarding force. In other words, ion atmosphere cannot reach the motion of an ion immediately when it moves through the liquid with a velocity produced by external electric field which led to a dissymmetry in the direction of the ion motion. This dissymmetry of charge density causes a retardation force on the moving ion and hence C ( b a) (3) where is angular velocity, Z 0 is characteristic impedance of coaxial line i.e. 50Ω, 0 is permittivity in free space, C 0 = capacitance of air, and C f is capacitance of fringing field in coaxial line. b and a is radius of external and internal conductor of coaxial probe, respectively as shown in Figure 7(b). Since C f can be ignored in the first approximation [18], Eq. (1) can be simplified as 1 j Z ( ' j ") 0( b a) 1 j Z 2.38( ' j ") ( b a) 0 0 When the coaxial line contact with solution, mismatch impedance is occurred, and hence causes reflection on the 0 (4)

5 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:14 No:05 63 aperture of coaxial probe. Meanwhile, when the impedance of solution approaches characteristic impedance of coaxial line, Fig. 10. The variation of dielectric constant, ε with percentage of salt content in water for different frequency Fig. 11. The variation of loss factor, ε with percentage of salt content in water for different frequency Fig. 12. The variation of magnitude of reflection coefficient, Г with frequency for different percentage of salt content in water

6 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:14 No:05 64 Fig. 13. The variation of reflection coefficient with percentage of salt in solution for different frequency using PNA in conjunction with Agilent 85052D High- Temperature dielectric probe mismatch impedance declined. It leads to the decrement of reflection coefficient as shown in Figure 15. Figure 13 illustrates that measured magnitude of reflection coefficient using the developed system over percentage of salt in water for 1.40GHz, 1.70GHz, 2.10GHz, 2.60GHz, and 2.80GHz. Meanwhile, the magnitude of reflection coefficient shown in Figure 13 exhibit anomalous trendline. They show skewed quadratic trendline. The reflection coefficient will increase as percentage of salt content in solution exceeds 8%. It is attributed to the increment of mismatch impedance as impedance of solution discrepant from characteristic impedance gradually when percentage of salt increases. As a result, the anomalous of trendline can be seen. Another explanation of this anomalous behavior is due to multiple reflections in the coaxial line [19]. In other words, the standing wave that occurred in coaxial line causes the oscillation of magnitude of reflection coefficient. It can be seen that the developed system has considerably high of accuracy as PNA in reflection measurement for frequencies of 1.40GHz, 1.70GHz, 2.10GHz, 2.60GHz, and 2.80GHz. Agilent 85052D High-Temperature probe was used to conduct the reflection measurement as shown in Figure 12 and Figure 13. Figure 14 illustrate the comparisons of magnitude of reflection coefficient for frequency 1.40GHz, 1.70GHz, 2.10GHz, 2.60GHz, and 2.80GHz. Trendlines shown in Figure 14(a)-(c) have anomalous behavior which is similar to Figure 10 and Figure 11 for all type of probes. When frequency is extended to 2.60 GHz and 2.80 GHz as shown in Figure 14(d)-(e), the magnitudes of reflection coefficient decreases when percentage of salt content vary from approximately 1% to 10%. When percentage of salt in solution exceeds 10%, the magnitude of reflection coefficient tends to become constant for all type of probes. In addition, Agilent 85052D High- Temperature dielectric probe exhibit the lowest of reflection coefficient among the probe. It is probably due to its dielectric filler of glass that present between inner and outer conductor which has complex permittivity of 5.4-j0.0108, since PTFE (Polytetrafluoroethylene) that presented in RG402/U and RG405/U has complex permittivity of 2.05-j The larger value of complex permittivity causes the smaller value of magnitude of reflection coefficient as described by Eq. (4). Although RG402/U and RG405/U use same dielectric filler and they have similar aspect ratio, ( b ), however, aperture of a RG402/U has longer radius than RG405/U. Hence, reflection coefficient of RG402/U is always greater than RG405/U. It can be described by Eq. (4) where increment of (b - a) term will lead to increment of reflection coefficient too. 4.2 Sugar content detection Figure 15 shows the variation of measured dielectric constant using PNA in conjunction with Agilent 85052D High-Temperature dielectric probe for different percentages of sugar content in water over frequency range from 200MHz to 20GHz. Overall, the dielectric constant of different percentage of sugar in water decreases when the frequency increases from 200MHz to 20GHz. In Figure 15, the sample with 5% of sugar content in water indicate the highest value of dielectric constant, whereas sample with 70%-75% of sugar content in water indicate the lower value of dielectric constant. The amount of free water molecule presented in the water is the key to determine the dielectric properties. When the percentage of added sugar in water is low, less free water molecule is bound with molecule of sugar. Free water molecule, H 2 O becomes dominator in solution. As a results, 5% of sugar content in solution show the highest dielectric constant, as which water has considerably high of dielectric constant. Free water molecule is barely to find in high percentage of sugar content in water or solution, for instance 80% sample. Hence, it can be seen that dielectric constant increase when percentage of sugar content in water decreases. Sugar molecules which are relatively large, uncharged, and non-polar can inhibit orientation polarization by the electromagnetic energy [20-21]. Therefore, the increment of

7 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:14 No:05 65 (a) (b) (c)

8 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:14 No:05 66 (d) (e) Fig. 14. Comparison of reflection coefficient over percentage of salt in solution using developed reflection measurement setup for frequency (a) 1.40 GHz, (b) 1.70 GHz, (c) 2.10 GHz, (d) 2.60 GHz, and (e) 2.80 GHz Fig. 15. The variation of measured dielectric constant, ε with frequency

9 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:14 No:05 67 sugar content will decline the dielectric constant. Since the molecule of sugar is relatively large, hence the moment inertia is greater if compare with molecule of water. The reorientation due to change of electromagnetic polarity is inhibited at low frequency due to moment inertia. Hence, the dielectric constant is relatively low at high percentage. On the other hand, loss factor decreases when frequency increases. It can be observed in Figure 16. It is due to the inability of sugar molecule to store charge at high frequency. This fact attribute to low dielectric constant at high frequency. When dielectric constant is low, the molecules are not able to store energy. Hence, the dissipation of energy may dissipate through conduction loss [22]. The rapid change of electromagnetic polarity at high frequency is asynchronous with frequency of charge oscillation and molecule reorientation. It causes the still state is presented at high frequency. Hence, the variation of loss factors at higher frequency seem level off due to insignificant friction and retardation encountered by sugar and water molecules Fig. 16. The variation of measured loss factor, ε with frequency presented in solution. In addition, the difference between molecule of sugar and salt in term of their relaxation frequency [23] causes contrast behavior of loss factor. Figure 17 shows the variation of dielectric constant of solution for different percentage of sugar in water measured by using PNA for 1.38GHz, 1.69GHz, 2.08GHz, 2.58GHz, and 2.77GHz. Figure 17 is clearly indicates that the dielectric constant decreases with increment in percentage of sugar content in water. Water has a relatively high dielectric constant [24] as any traces of moisture trapped or absorb will dramatically alter the desired dielectric properties. Hence, the presences of moisture content in sugar solution will vary the dielectric constant. For high moisture content, the free water molecule increases and sugars are dissolved. It leads to higher conductivity. Figure 18 shows the measured dielectric loss against percentage of sugar in water. Figure 18 indicates that the dielectric loss increases when percentage of sugar in water increases. Meanwhile, dielectric loss decreases beyond 50% Fig. 17. Measured Dielectric Constant vs. Percentage of sugar in water for frequency 1.40GHz, 1.70GHz, 2.10GHz, 2.60GHz, and 2.80GHz

10 Dielectric loss, ɛ'' International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:14 No: Percentage of sugar in water(%) 1.40GHz 1.70GHz 2.10GHz 2.60GHz 2.80GHz Fig. 18. Dielectric loss vs. percentage of sugar in water for 1.40GHz, 1.70GHz, 2.10GHz, 2.60GHz, and 2.80GHz of sugar content in water. It might be due to the absence of free water molecule in solution as the solution attains state of saturation beyond 50% of sugar in water. Molecules of sugar might have greater inertia than the water molecule. In the saturation state, free water molecule is not presented and the molecule of sugar is excessive. The inertia of sugar molecule may retard the oscillation of ion and hence, decrease the dielectric loss. The magnitude of reflection coefficient in Figure 19 was measured by using high temperature dielectric probe. The highest magnitude of reflection coefficient can be found at 1.40GHz when percentage of sugar in water increases. This trend is followed by 2.80GHz, 1.70 GHz, 2.60 GHz, and lastly at 2.10GHz. At frequency 2.10GHz, 2.60GHz, and 2.80GHz show obvious fall in magnitude of reflection coefficient from 5% to 50% of sugar in water. Reflection coefficient increases from 50% to 80% of sugar content in solution. At frequency 1.40 GHz and 1.70GHz, decrement of reflection coefficient occur from 5% to 60% of sugar in water. Beyond 60% of sugar in water, dielectric loss increase with sugar concentration up to 80% of sugar in solution. The similar trendline can be found as in Figure 13 and the explanation is similar as encountered in salinity measurement where it is associated with degree of mismatch impedance. Figure 20(a) shows the magnitude of reflection coefficient against percentage of sugar content in water for 3 different probes at 1.40GHz by using portable microwave detection system. The trendline shown in Figure 20(a) is similar as Figure 14(a). However, the detectable range of sugar content is wider than salinity measurement. Figure 14(a) and Figure 20(a) exhibit quadratic trendline. The turning point for salinity measurement occurred at 5 percent in saline water, while sugar content measurement occurred at 60% in sugar solution. The molecular weight of sugar and salt probably is the factor which causes the different in term of the turning point. On the other hand, it can be noticed that the salt attain the saturation state at lower percentage of salinity at approximately 5 percent. It might attribute to lower solubility of salt [25] than sugar. Meanwhile, sugar attains saturation at greater percentage than salt. It can be justified from Figure 20(a)-(e) Fig. 19: Magnitude of reflection coefficient vs. percentage of sugar in water for Portable Microwave Detection system measured by using high temperature probe

11 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:14 No:05 69 (a) (b) (c)

12 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:14 No:05 70 (d) (e) Fig. 20. Magnitude of reflection coefficient vs. percentage of sugar in water at frequency (a)1.40 GHz, (b) 1.70 GHz, (c) 2.10 GHz, (d) 2.60 GHz and (e) 2.80 GHz which measured by using portable microwave detection system with RG 402 coaxial probe, RG405 coaxial probe and Agilent 85052D high temperature probe if compared with Figure 14(a)-(e). The variation of magnitude of reflection coefficient with percentage of solvent is consistent for all type of sensors over the exhibited frequency range. 5. Conclusion A low cost microwave detection system which consists of main microwave components, i.e. VCO, directional coupler and RG402/U as well as RG405/U semi rigid coaxial probe for salt and sugar content in solution. These components are assembled for percentage of salt and sugar in solution. On the other hand, PNA in conjunction with Agilent 85052D High- Temperature probe are used to measure the dielectric constant and loss factor of solution with different percentage of salt (salinity) and sugar content (sweetness). The reflection measurements were then conducted using these probes for reflection coefficient and comparison was conducted in terms of its performance in salinity and sugar content detection in solution via reflection coefficient. It can be noticed that RG405 has better agreement with Agilent High Temperature Probe in measuring reflection coefficient for all selected frequency in salinity measurement. Meanwhile, RG405 performed consistently with High Temperature Probe. The variation of reflection coefficient over percentage of sugar content in solution is maintained at certain accuracy. RG402 performed inconsistently in sugar content detection comparing with RG405.

13 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:14 No:05 71 REFERENCES [1] B. Srilakshmi, Nutrition Science, 2 nd Edition, New Age International, India, [2] Edikom, Reformulation of products to reduce sodium: Salt Reduction guide for the Food Industry, Food Industry Guide, Canada, 2009 [3] American Heart Association, Sugars and Carbohydrates, HealthyDietGoals/Sugars-and Carbohydrates_UCM_303296_Article.jsp, 16 May 2013 [4] Cuiqin Wu, Diyun Chen, Hongmei Deng, Yonghui Liu, and Aiju Zhou, Determination of Anilines in Water Samples Using Ionic Liquid-Based Single Drop Microextraction Coupled with High Performance Liquid Chromatography, 5th International Conference on Bioinformatics and Biomedical Engineering, (icbbe) 2011, Page(s): 1 4, [5] Zhihao Ling, and Qinqin Wu, and Jinshou Yu, The research and development of ultraviolet-visible measurers of high performance liquid chromatography, Proceedings International Conference on Information Acquisition, 2004, Page(s): , [6] Zhou Xuefei ; Zhou Shi-Bing ; Zhang Yalei ; Shi Lu, "Determination of Triclosan in Wastewater Using Solid Phase Extraction and High Performance Liquid Chromatography with Ultra-Violet Detection 3rd International Conference on Bioinformatics and Biomedical Engineering, ICBBE 2009, Page(s): 1 4, [7] Xie Qing-jie, Dong Xiao-bo, and Liu Dong, Determination of Thiourea by High Performance Liquid Chromatography with Different Solvents, 5th International Conference on Bioinformatics and Biomedical Engineering, (icbbe) 2011, Page(s): 1 4, [8] Knipper, N.V. Use of high frequency currents of grain drying. Journal of Agricultural Engineering Research, 1953, 2: 185 [9] Dunlap, W.C., and Makower. (1945). Radio frequency dielectric properties of dehydrated carrots. Journal of Physical Chemistry 49: [10] Kundra, T.G.S.V.Raghavan, C, Akyel, R. Bosisio and F. R. van de Voort. Electromagnetic properties of milk and its constituents at 2.45MHz. Journal of Microwave power, (4): [11] D H Gadani, V A Rana, S P Bhatnagar, A N Prajapati & A D Vyas. Effect of salinity on dielectric properties of water. Indian Journal of pure & Applied Physics 50: , 2006 [12] Thomas M. Dauphine, John Ancsin, H. Peter Klein, M. John Phillips, The Electrical Conductivity of Weight Diluted and Concentrated Standard Seawater as a Function of Salinity and Temperature, IEEE Journal of Oceanic Engineering, VOL.OE-5, NO. 1, January 1980, pp [13] Meissner, T., and Wentz, F.J., The Complex Dielectric Constant of Pure and Sea Water From Microwave Satellite Observations, IEEE Transactions on Geoscience and Remote Sensing, Vol. 42, No. 9, September [14] Technical Overview: 85070E Dielectric Probe Kit, 200 MHz to 50 GHz, Agilent Technologies, Inc. [15] M. Hallikianen, F. T. Ulaby, M. C. Dobson, M. A. El-Rayes, and L. K. Wu, Microwave dielectric behavior of wet soil-part I: Empirical models and experimental observations, IEEE Trans. Geosci. Remote Sens., vol. GE-23, no. 1, pp , Jan [16] H. Falkenhagen. The principal ideas in the interionic attraction theory of strong electrolytes, Rev. Mod. Phys., vol 3, no. 3, pp , Jul [17] D. Bérubé, F. M. Ghannouchi, and P. Savard. A Comparative Study of Four Open-Ended Coaxial Probe Models for Permittivity Measurements of Lossy Dielectric/Biological Materials at Microwave Frequencies, IEEE Transactions on Microwave 'Theory and Techniques, Vol. 44, No. 10, pp , [18] G. B. Gajda and S. S. Stuchly. Numerical analysis of open-ended coaxial lines. IEEE Trans. Microwave Theory Tech., vol. MTT-31, no. 5, pp , [19] K. Y. You, J. Salleh, and Z. Abbas. Effects of Length and Diameter of Open-Ended Coaxial Sensor on its Reflection Coefficient. Radioengineering, Vol. 21, No. 1, , [20] Calay R.K.; Newborough, M.; Probert D.; Calay P.S. Predictive Equations for the Dielectric Properties of Foods. International Journal Food Science Technology, 1995, 29 (6), [21] Yaghmaee, P.; Durance T.D. Predictive Equations for Dielectric Properties of NaCl, D-sorbitol and Sucrose Solutions and Surimi at 2450 MHz. Journal of Food Science 2002, 67 (6), [22] Rajnish K. Calay, Marcus Newborough, Douglas Probert and Pargat S. Calay. Predictive equations for the dielectric properties of foods. International Journal of Food Science & Technology. Volume 29, Issue 6, pages , December [23] K. Fuchs and U. Kaatze. Molecular Dynamics of Carbohydrate Aqueous Solutions. Dielectric Relaxation as a Function of Glucose and Fructose Concentration. J. Phys. Chem. B, 2001, 105 (10), pp [24]G. C. Akerlof, H. I. Oshry. The Dielectric Constant of Water at High Temperatures and in Equilibrium with its Vapor. J. Am. Chem. Soc., 1950, 72 (7), pp [25] Zhenhao Duan, and Rui Sun. An improved model calculating CO 2 solubility in pure water and aqueous NaCl solutions from 273 to 533 K and from 0 to 2000 bar. Chemical Geology, Volume 193, Issues 3 4, 14 February 2003, Pages