Many problems arise in the operation of photovoltaic systems. Each these affects systems by reducing power entire system. Some can be avoided during design For example, when designing systems, it is possible to eliminate shading panels from surrounding objects. It also necessary look at neighboring calculate inclination sunlight based on position sun and distance between two accordingly. Howeve...

The string theory is a fast moving subject, both physics wise and in the respect of mathematics. In order to keep up with the discipline it is important to move with new ideas which are being stressed. Here I wish to give extracts from new papers of ideas which I have recently found interesting. There are six papers which are involved: I ."Strings formulated directly in 4 dimensions " A. N...

Insulator strings with several material and profiles are very common in overhead transmission lines. However, the electric field and voltage distribution of insulator string is uneven which may easily lead to corona, insulators’ surface deterioration and even flashover. So the calculation of the electric field and voltage distribution along them is a very important factor in the operation time....

The buckling behavior of rod strings in wellbore is one of the key issues in petroleum engineering. The slender rod strings in vertical wellbore were selected as research objects. Based on the energy method, the critical load formulas of sinusoidal and helical buckling were derived for the string with the bottom of the wellbore pressure. According to the sinusoidal and helical buckling’s geomet...