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We have started a new research project on a hybrid power generation system consisting of piezoelectric, thermoelectric and solar cell modules. In the first step, we have focused on the antireflection coating based on zinc oxide (ZnO) and metal nanolayers incorporated in solar cells. In layered structure containing ZnO and metal nanoscale layers, we have presented the possibility of increasing wave transmission in the visible region by adding the top and bottom cap layers. The enhancement of optical transmission is very important in improving the performance of sensor protections, solar cells, UV protective films and transparent conductive display panels electrode. It is found that, the structure containing both the top and bottom cap layers (S3) yields larger transmittance than the structures S1 without any cap or S2 just with one cap layer. The maximum transmittance in the visible range can be increased from 33% to 67%. In addition, for the TE mode (TM mode), the maximum value of transmission in the S1 and S2 structures occurs at angles close to normal incidence while in the S3 multilayer it happens around 1 radian, that is, the behavior of the TE mode is the opposite of the TM mode. Also, when the incident angle varies, the band edges experience a blue shift. The amount of TE shift is more pronounced than TM one. Moreover, the metal with higher plasma frequency will move the band gap edges to the higher frequencies.

The purpose of this paper is to theoretically investigate the properties of electromagnetic wave propagating in both one-dimensional periodic and quasiperiodic photonic crystals consisting of high-temperature yttrium barium copper oxide and strontium titanate dielectric nano-scale materials. By using the transfer matrix method, angle-, polarization- and thickness-dependences of created PBGs are explored individually for periodic and quasiperiodic structures, and some interesting features are presented in the results section. Such supposed structures can be used as very compact polarization sensitive splitters and defect-free multichannel narrowband tunable filters.

In this paper, by considering wave phase analysis, the density of modes, group velocity, and lateral shift in one-dimensional multilayer are theoretically computed by using the transfer matrix method in the terahertz domain. The proposed structure is based on the Fibonacci sequence constituted of uniaxial indefinite medium and S i O 2 layers. It is found that for both TE and TM beams, around an angle of 90º, the lateral shift is highly negative, while it is positive at the rest of the angles. Also, for non-vertical angles, a positive peak is observed about an angle of 60º (near the Brewster angle). Our numerical analysis shows that at angles less than about 10º, the lateral shift is negative for the TM mode. It is shown that for both polarizations the density of states (the group velocity) has maximum (minimum) value near the band gap edges, while inside the band gap it becomes minimum (maximum). Superluminal and subluminal cases can be defined here.

Background Pseudomonas aeruginosa is one of the most common Gram-negative pathogen causing nosocomial infection worldwide. The emergence of multi-drug resistant strains has become a major clinical concern in recent years. Resistance-nodulation-cell division (RND) family efflux pumps play an important role in the development of multidrug resistance in P. aeruginosa. Objectives The aims of the present study were to evaluate the antimicrobial susceptibility against carbapenems used and to evaluate the gene expression of two resistance nodulation cell division-type efflux pump systems (MexB and MexY) among carbapenem non-susceptible P. aeruginosa. Methods A total of 256 non-repetitive P. aeruginosa were collected from the different clinical samples of patients admitted in Qazvin and Tehran educational hospitals. Antimicrobial susceptibility testing was performed by standard Kirby-Bauer method. The expression of MexB and MexY genes was assessed by quantitative real-time polymerase chain reaction (qRT-PCR). Results In total, 107 (41.8%) isolates were non-susceptible to imipenem and/or meropenem. All carbapenem non-susceptible isolates were positive for the presence of MexB and MexY genes. The expression of MexB (P value = 0.004) and MexY (P value = 0.001) genes was significantly increased, compared to standard carbapenem sensitive strains. Conclusions The findings of the present study showed the considerable presence of carbapenem resistance among the clinical isolates of P. aeruginosa. The overexpression of MexB and MexY genes is also established among these resistant isolates collected from studied hospitals in Iran.

—In this paper, we theoretically study the phase treatment of reflected waves in onedimensional Fibonacci photonic quasicrystals composed of nano-scale fullerene and semiconductor layers. The dependence of the phase shift of reflected waves for TE mode and TM mode on the wavelength and incident angle is calculated by using the theoretical model based on the transfer matrix method in the infrared wavelength region. In the band gaps of supposed structures, it is found that the phase shift of reflected wave changes more slowly than within the transmission band gaps. Furthermore, the phase shift decreases with the incident angle increasing for TE mode, and increases with the incident angle increasing for TM mode. Also, for the supposed structures it is found that there is a band gap which is insensitive to the order of the Fibonacci sequence. These structures open a promising way to fabricate subwavelength tunable phase compensators, very compact wave plates and phase-sensitive interferometry for TE and TM waves.

We investigate the transmission properties of one-dimensional Fibonacci quasiperiodic structure consisting of dispersive and lossless epsilon-negative (ENG) materials. It is found that for both TE and TM polarizations with normal and oblique incidences, there exist transmission gaps which are invariant with a change of scale and sensitive to incident angles. Analytical methods based on transfer matrices and effective medium theory have been used to explain the properties of transmission gaps.

Existence of backward electromagnetic surface waves at an interface separating a semi-inflnite uniform left-handed metamaterial and a 1D photonic crystal composed of alternating layers of two kinds of single-negative (†-negative and "-negative) metamaterial is theoretically investigated. Dispersion characteristics of surface states are analyzed for two difierent cases of ENG-MNG and MNG-ENG layered periodic structures. It was demonstrated that in the presence of metamaterial, surface waves are sensitive to light polarization and there exist only backward TM-polarized (or TE-polarized) surface Tamm states depending on the ratio of the thicknesses of two periodic stacking layers.

We investigate the transmission properties of the Fibonacci quasiperiodic layered structures consisting of a pair of double positive (DPS), epsilon-negative (ENG) or/and mu-negative (MNG) materials. It is found that there exist the polarization-dependent transmission gaps which are invariant with a change of scaling and insensitive to incident angles. Analytical methods based on transfer matrices and efiective medium theory have been used to explain the properties of transmission gaps of DPS-MNG, DPS-ENG and ENG- MNG Fibonacci multilayer structures.

Research has shown that shift work, in particular night work, can have negative effects on the health, safety and well-being of workers. Our study assessed, in a hospital setting, the effects of bright light (BL) on general health and psychological problems during night shift work. In an experimental design, 15 female nurses at a general hospital that located in Tehran were exposed to moderate bright light (2000 lx) during night work. The evaluation of general health status, job stress, and burnout syndrome conditions was done as follows: The 28-item General Health Questionnaire (GHQ-28) was used as a screening tool for the detection of general health status; for assessing the level of stress, perception stress scale (PSS) was filled; and for burnout syndrome conditions, burnout self-report questionnaire (BSR) was completed. T-test and paired t-test analysis were used to assess the association between BL exposure for a total of 30 min during each night shift and changes in general health status, job stress and burnout syndrome. This study clearly shows that BL administration could not reduce anxiety symptoms, somatic symptoms, severe depression and improved social dysfunction significantly during night shift. However, BL exposure significantly decreased the perception stress (P=0.008) and burnout syndrome (P=0.06) during night permanent shift. These results suggest that BL might have provoked changes in perception stress and burnout syndrome of nurses working night permanent shift.

This study deals with artificial neural network (ANN) modeling of a diesel engine using waste cooking biodiesel fuel to predict the brake power, torque, specific fuel consumption and exhaust emissions of the engine. To acquire data for training and testing the proposed ANN, a two cylinders, four-stroke diesel engine was fuelled with waste vegetable cooking biodiesel and diesel fuel blends and operated at different engine speeds. The properties of biodiesel produced from waste vegetable oil was measured based on ASTM standards. The experimental results revealed that blends of waste vegetable oil methyl ester with diesel fuel provide better engine performance and improved emission characteristics. Using some of the experimental data for training, an ANN model was developed based on standard Back-Propagation algorithm for the engine. Multi layer perception network (MLP) was used for non-linear mapping between the input and output parameters. Different activation functions and several rules were used to assess the percentage error between the desired and the predicted values. It was observed that the ANN model can predict the engine performance and exhaust emissions quite well with correlation coefficient ( R ) 0.9487, 0.999, 0.929 and 0.999 for the engine torque, SFC, CO and HC emissions, respectively. The prediction MSE (Mean Square Error) error was between the desired outputs as measured values and the simulated values were obtained as 0.0004 by the model.

A comprehensive combustion analysis has been conducted to evaluate the performance of a commercial DI engine, water cooled two cylinders, in-line, naturally aspirated, RD270 Ruggerini diesel engine using waste vegetable cooking oil as an alternative fuel. In order to compare the brake power and the torques values of the engine, it has been tested under same operating conditions with diesel fuel and waste cooking biodiesel fuel blends. The results were found to be very comparable. The properties of biodiesel produced from waste vegetable oil was measured based on ASTM standards. The total sulfur content of the produced biodiesel fuel was 18 ppm which is 28 times lesser than the existing diesel fuel sulfur content used in the diesel vehicles operating in Tehran city (500 ppm). The maximum power and torque produced using diesel fuel was 18.2 kW and 64.2 Nm at 3200 and 2400 rpm respectively. By adding 20% of waste vegetable oil methyl ester, it was noticed that the maximum power and torque increased by 2.7 and 2.9% respectively, also the concentration of the CO and HC emissions have significantly decreased when biodiesel was used. An artificial neural network (ANN) was developed based on the collected data of this work. Multi layer perceptron network (MLP) was used for nonlinear mapping between the input and the output parameters. Different activation functions and several rules were used to assess the percentage error between the desired and the predicted values. The results showed that the training algorithm of Back Propagation was sufficient enough in predicting the engine torque, specific fuel consumption and exhaust gas components for different engine speeds and different fuel blends ratios. It was found that the R2 (R: the coefficient of determination) values are 0.99994, 1, 1 and 0.99998 for the engine torque, specific fuel consumption, CO and HC emissions, respectively.