Abstract: This paper aims to analysis the behavior of DC corona
discharge in wire-to-plate electrostatic precipitators (ESP). Currentvoltage
curves are particularly analyzed. Experimental results show
that discharge current is strongly affected by the applied voltage. The proposed method of current identification is to use the method
of least squares. Least squares problems that of into two categories:
linear or ordinary least squares and non-linear least squares,
depending on whether or not the residuals are linear in all unknowns.
The linear least-squares problem occurs in statistical regression
analysis; it has a closed-form solution. A closed-form solution (or
closed form expression) is any formula that can be evaluated in a
finite number of standard operations. The non-linear problem has no
closed-form solution and is usually solved by iterative.
Abstract: This study and the field test comparisons were carried
out on the Algerian Derguna – Setif transmission systems. The
transmission line of normal voltage 225 kV is 65 km long,
transported and uses twin bundle conductors protected with two
shield wires of transposed galvanized steel. An iterative finite-element method is used to solve Poisons
equation. Two algorithms are proposed for satisfying the current
continuity condition and updating the space-charge density. A new approach to the problem of corona discharge in
transmission system has been described in this paper. The effect of
varying the configurations and wires number is also investigated. The
analysis of this steady is important in the design of HVDC
transmission lines. The potential and electric field have been
calculating in locations singular points of the system.
Abstract: Steel corrosion in concrete is considered as a main
engineering problems for many countries and lots of expenses has been paid for their repair and maintenance annually. This problem
may occur in all engineering structures whether in coastal and offshore or other areas. Hence, concrete structures should be able to
withstand corrosion factors existing in water or soil. Reinforcing
steel corrosion enhancement can be measured by use of concrete
electrical resistance; and maintaining high electric resistivity in concrete is necessary for steel corrosion prevention. Lots of studies
devoted to different aspects of the subjects worldwide. In this paper, an evaluation of the effects of W/C ratio, cementitious materials, and
percent increase in silica fume were investigated on electric resistivity of high strength concrete. To do that, sixteen mix design
with one aggregate grading was planned. Five of them had varying amount of W/C ratio and other eleven mixes was prepared with
constant W/C ratio but different amount of cementitious materials.
Silica fume and super plasticizer were used with different proportions
in all specimens. Specimens were tested after moist curing for 28 days. A total of 80 cube specimens (50 mm) were tested for concrete
electrical resistance. Results show that concrete electric resistivity can be increased with increasing amount of cementitious materials
and silica fume.