Any defects in street trees may cause injuries to human, vehicles and buildings. This research was investigated in the Babol city, Mazandaran province, in the northern state of Iran.Used the perfect inventory methods and measured the diameter at breathe height (DBH), height and hazardous criteria (dead woods, cracks or seams, decay, wound or cankers, root problems, weak branch unions and skew f...

An experimental study is reported on natural convection heat transfer from a helical heating coil to the surrounding fluid. The coil is heated electrically and the surrounding fluid is selected to be water. The range of parameters are: Rayleigh number, 879 ?£ Ra ?£ 780168, Prandtl number, 4.22 ?£ Pr ?£ 10.02, dimensionless coil diameter,7.69 ?£ Dave /d ?£ 10.77, number of coil rings, 2 ?£ N ?£ ...

In recent years, using Sol-gel procedure for the purpose of laboratory and industrial synthesis of Nano-structures, and especially silica Nano-particles, has been significantly increased. In this research, silica particles were synthesized by Sol-gel procedure and their physical and chemical properties were studied by means of scanning electron microscopy (SEM), transmission electron microscopy...

This paper presents a Computational Fluid Dynamics (CFD) model of pilot scale dissolved air flotation (DAF) tank. A Multiphase Mixture was used to analyse the influence bubble sizes on formation stratified flow structure. Critical diameter is defined as size that implies equality rising velocity and downward in separation zone (SZ). The fact whether using which are greater or less than critical...

In recent years, using Sol-gel procedure for the purpose of laboratory and industrial synthesis of Nano-structures, and especially silica Nano-particles, has been significantly increased. In this research, silica particles were synthesized by Sol-gel procedure and their physical and chemical properties were studied by means of scanning electron microscopy (SEM), transmission electron microscopy...

In 1978, Chvátal and Thomassen proved that every 2-edge-connected graph with diameter 2 has an orientation with diameter at most 6. They also gave general bounds on the smallest value f(d) such that every 2-edge-connected graph G with diameter d has an orientation with diameter at most f(d). For d = 3, their general bounds reduce to 8 ≤ f(3) ≤ 24. We improve these bounds to 9 ≤ f(3) ≤ 11.