Water is one of the most vital constituents in plants. In this research, for an estimation of leaf moisture content, the variation of capacitance was employed. The variations were measured via designed and manufactured capacitive sensors. The objective of the research was to estimate leaf moisture content by measuring its capacitance for five agronomic crops. Experiments for measuring leaf capacitance were performed on maize, sorghum, capsular bean, white bean and sunflower at two frequencies of: 100 kHz and 1 MHz. The results showed that in all cases the best fitted curve for variations of the capacitance in relation to leaf moisture percentage was in the form of an exponential function namely: y= aebx (where y is capacitance, x is leaf moisture content, a is the linear coefficient, and b is the exponential coefficient). Parameters a and b for different plants of each crop and each frequency were not significantly different at 1% probability level. However, these coefficients were significantly different among different crops. Coefficients of determination were higher at 100 kHz than at 1 MHz. It was also observed that the higher the leaf moisture the more the data points scattered around the best-fit line, although the scattering was more uniform at 1 MHz.

Electrical capacitance Tomography (ECT) is an imaging technique that maps the electrical permittivity contrast of the object. This paper studies an image and a shape reconstruction method for ECT. For image reconstruction, a regularized Gauss-Newton method has been implemented, based on the inverse finite element technique. For shape reconstruction, a . narrow band level set method has been developed. Using experimental ECT data, a comparative study of these two techniques is the main objective of this paper.

This paper presents a wide input voltage range Negative impedance converter (NIC) circuit operating in weak inversion. A small signal analysis has been performed, resulting in a circuit model that characterises the input impedance function, Zin(s). A boosted folded cascode (BFC) OTA is presented using the proposed NIC. Incorporating the proposed NIC at the output node of a folded cascode (FC) OTA, the output impedance is increased, resulting in a noticeable improvement in the overall voltage gain without phase margin (PM) degrading. Post-layout simulation is performed using standard 180nm CMOS technology, while the two essential large resistors of the proposed NIC are considered off-chip components. The boosted OTA exhibits a DC gain improvement of 17 dB with no PM degradation over a conventional FC OTA at the expense of 1.5% more power consumption. The proposed NIC circuit can be incorporated easily into any boosted OTA realized by alternative methods. Based on this concept, a double-boosted OTA is also introduced.

The graphene (GR) has attracted intensive interest due to its two-dimensional and unique physical properties. In the present study, the graphene sheets were synthesized by electrochemical exfoliation of graphite in sulfuric acid solution. The polybithiophene-graphene (PbTh-GR) composite films deposited onto indium tin oxide substrate (ITO/PbTh-GR) have been prepared by the incorporation of graphene sheets into the PbTh matrix during electropolymerization under magnetic stirring from the LiClO4/CH3CN electrolyte containing the bithiophene (bTh) monomer and graphene sheets. The incorporation of graphene sheets at different masses (1, 2 and 3 mg) is ensured by the effect of the stirring of the electrolyte. The characterisation of films is effected by electrochemical methods (cyclic voltammetry and impedance spectroscopy), spectroscopic technics (FT-IR, UV-Visible), X ray diffraction, thermogravimetric analysis, and scanning electron microscopy. It was observed that the electrochemical performance measurements of the ITO/PbTh-GR (3 mg) film show a specific capacity of around 65 F/g, which is six times higher than that of ITO/PbTh films, 11 F/g.

In designing a parallel resonant induction heating system, choosing a proper capacitance for the resonant circuit is quite important. The capacitance affects the resonant frequency, output power, heating efficiency and power factor. In this paper, with consideration to function of the equivalent series resistance (ESR), optimal capacitance is calculated.The induction heating resonance capacitor is achieved using Smart Bacteria Foraging Algorithm (SBFA) under voltage and frequency constraints for minimizing cost function that is including: increasing the output power and efficiency of an induction heater, while decreasing the power loss of the capacitor. The proposed algorithm mimics chemotactic behavior of E. Coli bacteria to optimize parameters. The proposed algorithm enjoys individual and social intelligence, so that it can search influx ways among hidden layers of the problem. Based on the equivalent circuit model of an induction heating system, the output power, and the capacitor losses are calculated. The effectiveness of the proposed method is verified by computer simulations, also improving the obtained results using SBFA are compared to classical bacteria foraging algorithm BFA.