In this paper, FINITE element method is used to obtain thermal CONDUCTIVITY coefficients of single-walled carbon nanotube reinforced polypropylene. For this purpose, the two-dimensional representative volume elements are modeled. The effect of different parameters such as nanotube dispersion pattern, nanotube volume percentage in polymer matrix, interphase thickness between nanotube and surrounded matrix and nanotube aspect ratio on the thermal CONDUCTIVITY coefficient of nanotube/polypropylene nanocomposite are investigated. For the dispersion pattern, three different algorithms, including random dispersion, regular dispersion along the temperature difference and regular dispersion perpendicular to the temperature difference are employed. Furthermore, the temperature is considered in the range of 0° C to 200° C. The nanotube volume percentage in the polymer matrix is selected as 1%, 3% and 5%. It is shown that the polypropylene matrix reinforced by the regular distribution of nanotubes directed parallel to the temperature difference leads to the largest thermal CONDUCTIVITY coefficients. Besides, the nanocomposites with larger volume percentages of carbon nanotubes possess larger thermal CONDUCTIVITY coefficients.

Introduction: I rreversible electroporation (IRE) is a process in which the membrane of the cancer cells are irreversibly damaged with the use of high-intensity electric pulses, which in turn leads to cell death. The IRE is a non-thermal way to ablate the cancer cells. This process relies on the distribution of the electric field, which affects the pulse amplitude, width, and electrical CONDUCTIVITY of the tissues. The present study aimed to investigate the relationship of the pulse width and intensity with the CONDUCTIVITY changes during the IRE using simulation.Materials and Methods: For the purpose of the study, the COMSOL 5 software was utilized to predict the CONDUCTIVITY changes during the IRE. We used 4, 000 bipolar and monopolar pulses with the frequency of 5 kHz and 1 Hz, width of 100 ms, and electric fields of low and high intensity. Subsequently, we built three-dimensional numerical models for the liver tissue.Results: The results of our study revealed that the CONDUCTIVITY of tissue increased during the application of electrical pulses. Additionally, the CONDUCTIVITY changes increased with the elevation of the electric field intensity.Conclusion: As the finding of this study indicated, the IRE with high-frequency and low electric field intensity could change the tissue CONDUCTIVITY. Therefore, the IRE was recommended to be applied with high frequency and low voltage.

Changes of up to 80°C has been reported for oral cavity temperature. This could well effecti on the nature of restorations for example failure of bonding of adhesive restorations. It is advocated that using opaque layer in porcelane to restorations could reduce this problem. This experimental study was designed to evaluate the effect mentioned using FINITElement analysis method.Results showed that cooling has a more destructive effect than warming process restorations with the presence of opaque having a FINITElement analysis effect on restorations.

Aims: In irreversible electroporation process, the membrane of cancer cells is damaged irreversibly by electric pulses of high-intensity field, which in turn leads to cell death. Factors influencing the field distribution include voltage, pulse width, and electric CONDUCTIVITY of tissue. The present study was conducted with the aim of evaluating CONDUCTIVITY changes of liver tissue during irreversible electroporation and calculation of the electric field distribution. Materials & Methods: In the present experimental study, using simulation, the relationship between pulse width and voltage intensity of each pulse was investigated in CONDUCTIVITY changes during irreversible electroporation, and the electric field distribution was calculated. In this simulation, in order to solve the equations, the software COMSOL 5 was used. Needle electrodes were used, and the liver tissue was considered as the target tissue. Eight pulses with the stimulated frequency of 1Hz, pulse width of 100μ s and 2ms, and the intensity of the electric fields ranging from 1000 to 3000v/cm were used as electric pulses. Findings: CONDUCTIVITY of tissue increased during sending the electrical pulses. The CONDUCTIVITY changes in the tip of the electrodes were more than the area between the two rows of electrodes. As the intensity of the pulsed electric field increased, the tissue CONDUCTIVITY also increased. When the CONDUCTIVITY of the tissue was constant and variable, the maximum electric field intensity was obtained 3879 and 3448v/cm. Conclusion: While electric pulse transmission, tissue CONDUCTIVITY increases. The electric field distribution depends on the CONDUCTIVITY at the desired point and by changing this CONDUCTIVITY due to the electroporation, the electric field distribution also changes and the maximum intensity of the electric field decreases.

Background and Aim: The movement of molars has been evaluated in many studies to correct Cl II malocclusion by non-compliance appliances but the results are controversial. The aim of this study was to compare the upper first and second molars' movement in cervical headgear (HG) and pendulum appliance (PEND) by FINITE element method.Materials & Methods: For modeling process, one of the best dry skulls was CT scanned (l mm slices). Modeling was done according to the mechanical properties of cortical and trabecular bone of maxilla and PDM and teeth and transferred to computer by scanner. Elementing, meshing and loading was done. The magnitude of force for both appliances was 250 gr and line of force for HG was 20 degree above the occlusal plane action and for PEND was along the midlingual surface of upper first molar crown. Tooth movement analysis was performed by the software named Ansys 5.71.Results: The amount of dislocation of the 1st molar cusps tip (mesiobuccal, mesiopalatal, distobuccal, distopalatal) at presence of second molar in bucco-lingual dimension showed distal-in rotation in HG and mesial-in rotation for pendulum. In mesio-distal dimension, the four cusps of 1st molar moved distally in HG and palatal cusps moved more in PEND. In vertical dimension, 1st molar showed extrusion in HG and intrusion in PEND for distal cusps.Conclusion: The presence of second molar had impact on the quality of upper first molar in both appliances and it moved in a distal direction, extruded and buccal drifted in both of them. Therefore, with regard to the cooperation of the patients, pendulum appliance is recommended to correct Cl II malocclusion instead of cervical headgear.

In order to predict the behavior of soil-related phenomena, it is necessary to have knowledge about unsaturated flow and using models that provide optimal estimates of the retention curve and hydraulic CONDUCTIVITY of soils. Despite the widespread use of the classic van Genuchten-Mualem model (VGM), this model usually performs poorly in predicting hydraulic CONDUCTIVITY and modification of some of its parameters seems necessary. In this research, 283 soils from different textures of the UNSODA bank were selected and divided into two sections of calibration and validation and their soil parameters were exported and categorized. Then, by defining the modified unsaturated hydraulic CONDUCTIVITY (Ksc) instead of the saturated hydraulic CONDUCTIVITY (Ks) and determining the limits for l and n parameters, the hydraulic CONDUCTIVITY-moisture function of VGM were solved using 24600 pairs of points li and nj for each soil of the three main soil texture classes. In the following, the optimal l value (l̂) of each texture class was selected based on the minimum value of the hydraulic CONDUCTIVITY estimation error using the root mean square error (RMSE) index and the n values that had created the minimum errors, were selected as the optimal pore size distribution coefficients of the hydraulic CONDUCTIVITY-moisture function (n̂opt). In order to create pedotransfer functions for estimating n̂opt, we ran stepwise regression in MATLAB software considering the condition of statistical significance (P-value=0.05) for independent variables and functions for each soil texture class. After creating pedotransfer functions, the results of the proposed method of this research (MVGM) were compared with the VGM results using RMSE and Nash-Sutcliffe (NSE) indices. The results showed that in both sections of creation and validation functions, the MVGM performed better in estimating hydraulic CONDUCTIVITY and had a higher efficiency index in all textural classes of soil.

Application of feed pellets in animal and aquatic farming industries has grown because of both the physical and the nutritional benefits it provides. Development of feed pellets manufacturing industry is also considerable. Steam conditioning process, which plays an important role in pelleting production, includes heating feed particles, adding moisture, and mixing the mash. Pellets cooling and drying processes are also involved in heat transfer phenomena. In this study, thermal CONDUCTIVITY of feed pellets was determined at different temperatures ranging from 25 to 85oC and moisture contents of 11.8 to 18.2% wb. It was measured by the transient technique using the line heat source method assembled in a thermal CONDUCTIVITY probe. It turned out that decreasing moisture contents from 18.2 to 11.8% (wb) produced non-linear reduction in thermal CONDUCTIVITY.The average values of thermal CONDUCTIVITY changed from 0.1509 to 0.2143 W m-1 oC-1 at different moisture contents. Tests conducted on two pellet size categories (based on nominal diameter) revealed a significant difference in thermal CONDUCTIVITY between these categories. The thermal conductivities of the first category (minor than nominal dia.) appeared to be 8.5% higher than those of the second category (superior to nominal dia.).Average values of thermal CONDUCTIVITY changed from 0.1538 to 0.2333 W m-1 oC-1 for the first category and from 0.1235 to 0.2456 W m-1 oC-1 for the second category (in 25oC). In addition, some empirical models were developed to express thermal properties as a function of moisture content and temperature.