No abstract

The nonlinear coupling of two high-power laser beams in plasmas in the presence of a transverse, static electric field is investigated to generate a difference frequency terahertz (THz) radiation. The relativistic variation of electron mass in the presence of two high-power laser beams is responsible for producing a nonlinear current driving the THz radiation. For typical laser and plasma parameters, we report the efficiency of the order of ~10−4 for the current scheme.

A fuel cell is an effective tool for extracting chemical energy from a special type of gaseous fuel other than fossil fuels. It is expected to be a replacement for thermal engines and rechargeable batteries within the next few years as they are emissionfree and not subjected to Carnot restrictions. The fuel cell can be manufactured in different sizes depending on the amount of energy required, where it can be too small to be used in precision equipment or large enough to work as electrical stations. This proposal shows a demonstration of the principle of work involved in the fuel cells, structure components, and practice ideas to enhance the output power.

The research studies the effects of some weather parameters for Baghdad city on the output of the solar module of the type monocrystalline. The experimental part measures the electrical parameters of the photo-voltaic (PV) module for three levels of radiation rate 500, 750, and 1000 W/m 2 . The theoretical part includes the modeled and simulation of the PV panel, via the proposed mathematical single-diode model (SDM, 5 parameters), and Matlabsimulation. The Newton Raphson method was applied to find the output current of the solar panel and the plotting P-V, I-V curves. The work involves preparing a simple mathematical model to estimate the optimal ambient conditions to give the highest output of the solar module. The validation of the model was verified by the practical testing of the cell for 6 months. The best results were obtained at standard testing conditions (25℃, 1000 W/m 2 ). The output power calculated by the mathematical model was 30.1 W while from experimental work was 30.45 W. The relative error is 1.15%. The converge between experimental and modeling results for the same conditions is about 98.9% that proves the validity of the proposed model and the possibility of using it for all types of photovoltaic.

We reported titanium dioxide nanoparticles solution (TiO 2 NPS) preparation by the sol-gel method. The produced NPS was employed as a liquid crystal to generate the second harmonic (SH) of one part of the pumping Nd: YAG laser at different pumping intensities. The remaining part of the pumping laser was focused on a stander nonlinear material (NPP63) to produce another SH pulse (to be used as a reference). Then the two SH pulses (one from TiO 2 and one from NPP63) were used to calculate the nonlinear coefficient (β) of the synthesized TiO 2 Nano solution. The suggested method represents a simple and inexpensive setup for calculation β by excluding the very expensive femtosecond laser used in previous studies. The results reveal that β for the prepared TiO 2 nanoparticles is very large (5.3Â10 À26 esu).