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This paper calculates the propagation loss in mixed-path mobile communication using parabolic equation method. The implicit finite differences scheme of the Crank-Nicolson type is applied in order to get the solution of the parabolic equation. The propagation is considered in 15 0 in the direction paraxial and the complex refractive index was considered what increases its precision. To validate the method, a radio propagation measurement campaign was carried out, in the county of Benfica, near the city of Belém, State of Pará. The frequency used was 900 MHz. The results were compared to the simulations made with the proposed method, which presented the best performance comparing to others works in literature. The loss predicted by this method had a mean error of 3.40 dB and standard deviation of 2.75 dB in relation to the measured data.

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We present an analysis on molecular dynamics between H2 molecule interacting with one carbon nanotube section at low initial-temperature of simulation, corresponding to 10−3 K, and under constant electric field effects, in order to verify the performance of the carbon nanotube like a H2 sensor, and consequently, indicating its use as an effective internal coating in storage tanks of hydrogen gas. During simulations, the H2 was relaxed for 40 ps inside and outside of carbon nano-tube, describing each possible arrangement for the capture of H2, and electric field was applied over the system, longitudinally to the carbon nanotube length, promoting the rise of an evanescent field, able to trap H2, which orbited the carbon nanotube. Simulations for electric fields intensities in a range of 10−8 au up to 10−6 au were performed, and mean orbit radius are estimated, as well as, some physical quantities of the system. The quantities calculated were: kinetic energy, potential energy, total energy and temperature in situ, among molar entropy variation. Our results indicates that a combination of electric field and van der Walls interactions derivatives of carbon nanotube is enough to create an evanescent field with attractive potential, showing it system as a good H2 sensor.