Wenner direct contact method is a method of estimating apparent electrical CONDUCTIVITY (ECa) of agricultural soils in situ. This method can be affected by factors such as quality of electrodes in contact with soil, type of employed electric current, moisture content, clay content and compaction of soil. In this research, the effect of electrode type (rod and plate) and electric current type (direct and alternating) on accuracy of estimating soil ECa has been investigated to design a soil EC mapper. A prototype soil EC meter based on direct contact method has been made. The device assessed by a completely randomized experimental design with factorial layout. The independent variables were soil salinity (five levels), electrodes type (two levels) and current type (two levels).Four soil types with different clay contents from regions around Mashhad city (Khorasan Razavi, Iran) have been used with three replications. The results analyzed with SPSS17 software and validated with 1:1 soils water extract EC’s. Significant difference between electrodes types and electric current types was observed. The correlation coefficients of direct contact measured EC’s with soil water extract EC’s was between 0.94 and 0.99 for all treatments. Based on the results of this research, plate type electrodes and AC current were recommended for the design of tractor rear mounted soil EC mapper.

Hydraulic CONDUCTIVITY and effective porosity are the most important parameters in determining drain spacing. These properties have temporal and spatial variation and estimating average values for them is difficult and costly. In this study, one dimensional differential equation of unsteady flow towards drainage was numerically solved using the control volume approach. Then by selecting a proper optimization algorithm, an inverse model was developed, calibrated and verified. In addition to numerical model, Glover-Dumm analytical solution was also used for the development of an inverse model. Then saturated hydraulic CONDUCTIVITY and effective porosity were estimated using these numerical and analytical inverse models. Results indicated, that using values of hydraulic CONDUCTIVITY and effective porosity obtained from numerical inverse model compared to experimental ones, resulted in a more accurate prediction of water table by proposed numerical method. Also, the efficiency of the proposed numerical model ( 0.93 ) is higher than the analytical ones (0.75).

A simple equivalent circuit to explain the electrical response of an ionic conductor is a parallel circuit consisting of an electrical resistance and a capacitor. Impedance semicircle of such a circuit is exactly a semicircle, but the impedance semicircle of experimental data is a depressed one. To explain this deformed shape of semicircle, usually CPE (constant phase element) is used in equivalent circuit instead of the capacitor. There are just a few theoretical researches about this element, which explain the deformed shape by fractals based on the surface roughness. The present work investigated the surface roughness and rejected its influence on the shape of impedance semicircle by using experimental data. An equivalent circuit is offered for ionic conductors based on the CMR “Concept of Mismatch and Relaxation” model.

This paper presents the bidirectional evolutionary structural optimization (BESO) method for the design of two-phase composite materials with optimal properties of stiffness and thermal CONDUCTIVITY. The composite material is modelled by microstructures in a periodical base cell (PBC). The homogenization method is used to derive the effective bulk modulus and thermal CONDUCTIVITY. BESO procedures are presented to optimize the two individual properties and their various combinations. Three numerical examples are studied. The results agree well with those of the benchmark microstructures and the Hashin-Shtrikman (HS) bounds.

In the present work, the thermal CONDUCTIVITY coefficients of nanoparticle-oil suspensions for two types of carbon nanotubes, single-walled (SWNTs) and multi-walled (MWNTs) carbon nanotubes at 0.1, 0.2 and 0.3 wt.% were measured by a modified transient hot wire method (KD2-pro thermal property meter). Results showed that the thermal CONDUCTIVITY of suspension containing single-walled carbon nanotubes is higher than that of suspension containing multi-walled carbon nanotubes. It was also observed that the thermal CONDUCTIVITY coefficients of both nanofluids increase with increasing temperature.

Nanotechnology research has proved sustainable results for a wide range of applications from engineering to medical science. Nanotechnology corresponds to the engineering of materials in nanosize (10-9m) whose material properties differ from of bulk properties. Nanofluid is one category of applications reported for its use as thermal management in cooling of electronic devices and fuel cell applications. In most literature, electrical CONDUCTIVITY studies were used as a basis to define the stability of nano-suspensions. In the present paper, the electrical CONDUCTIVITY studies of two glycol based nanofluids dispersed with ZnO nanoparticles of 50nm average diameter in the temperature range of 30-550C are reported. ZnO nanoparticles are added to the aqueous glycol base fluid prepared with (30 EG: 70 Water) and (30 PG: 70 Water) composition at a low volume concentration of 0. 01 to 0. 05%. Correlations are developed using experimental results for each volume concentration to predict electrical CONDUCTIVITY (EC) of nanofluids with temperature. From obtained results, the electrical CONDUCTIVITY of aqueous propylene glycol shows a decrement in EC after adding ZnO nanoparticles (except at 0. 04% volume concentration) and vice versa for aqueous ethylene glycol. For aqueous propylene and ethylene glycol nanofluids, electrical CONDUCTIVITY enhancement up to 20% and 12% is obtained at a volume concentration of 0. 04% and 0. 01% at 550C temperature respectively. The electrical CONDUCTIVITY of both nanofluids increases with increase in temperature at all volume concentrations.

Purpose: Irreversible electroporation is a physical process which is used for killing the cancer cells. The process that leads to cell death in this method is a unique process. Thermal damage does not exist in this process. However, the temperature of the tissue also increases during the electroporation. In this study, we aim to investigate the effect of CONDUCTIVITY changes on tissue temperature increase during the irreversible electroporation process. Materials and Methods: To perform simulations and solve equations, COMSOL MultiPhysics has been used. Standard electroporation pulse sequence (8 pulses with different electric field intensities) was used as a pulse sequence in the simulation. Results: During the electroporation process, the electrical CONDUCTIVITY and the temperature of the tissue were increased. Changes in the tissue temperature in the simulation with variable electrical CONDUCTIVITY are more than in the simulation with constant electrical CONDUCTIVITY during the electroporation process. This difference for pulses with more vigorous electric field intensity and points closer to the electrodes has been achieved more. Conclusion: To more accurately estimate and calculate the temperature and thermal damage inside the tissue during the irreversible electroporation process, it is suggested to consider the effect of CONDUCTIVITY changes during this process.

Mirage effect is contactless and non destructive method which has been used a lot to determine thermal properties of different kind of samples, transverse photothermal deflection PTD in skimming configuration with ccd camera and special programs is used to determine thermal CONDUCTIVITY of porous silicon ps film. Ps samples were prepared by electrochemical etching. Thermal CONDUCTIVITY with porosity changing was measured and the experiments result compared with theoretical results, and they were almost the same.