URB-CORR 2007 - Call for papers Dear Colleague, You are cordially invited to attend the 6th International Conference "Study and Control of Corrosion in the Perspective of Sustainable Development of Urban Distribution Grids" - URB-CORR 2007 to be held June 20-23, 2007 at the Technical University of Cluj-Napoca in Romania and to submit papers. The main topics of the conference are: 1. A.C. and D.C. stray currents 2. Study and control of underground

The European operators of energy transportation systems - pipelines – have reported numerous failures (corrosion defects – defects / holes in the metal of gas and oil pipes) in the last two decades. This majority of these failures are due to a new form of corrosion, namely stray currents corrosion. Issue of the operational safety for these grids (gas and oil pipelines) is of great impact: economic, social and environmental. Therefore the scientists

We have studied the factors that are determining the exploitation safety of cables afferent to the underground power lines. Therefore, we have experimentally determined the resistance of the polymeric (PVC) material, from which the protecting layer of medium voltage cables is made, to the action of fungi. We have analyzed the degradation causes of the dielectric rigidity of underground power lines.

There has been studied the degradation stage by corrosion of the metallic screen of the power cables afferent to some underground power lines (UPL), that are situated in different type of soils, with and without d.c. stray currents. And so, by electrochemical measurements, has been determinate the screen / soil potentials (Ecor), and by electric measurements, has been determinate the screen / soil and the hot wire / screen insulating resistance and

We have analyzed the degradation by corrosion of concrete steel sustaining elements involved in the systems for energy transportation and distribution. From the analysis of several steps of mechanism it is concluded that their degradation is caused by the emphasized corrosion of the concrete steel due to a.c. stray currents

The degradations by corrosion of great dimension underground concrete steel structures, frequently used at cities infrastructure constructions, are increased by d.c. and a.c. stray currents. In this paper, the results of experimental studies about pH and chemical composition modifications, due to d.c. and a.c. stray currents are presented.

With the aim to study the degradation mechanisms of concrete steel structures under the influence of stray currents, we have determined, on cylindrical samples, the evolution in time of volumic electrical resistance and breakage resistance, too. The determinations were performed comparatively, on control samples and samples affected by the constraint of polarization currents in A.C. and D.C., in 1%NaCl a queans solution

The corrosion degradation of concrete steel structures and the repair costs of corrosion-caused damages have been analyzed. Also, the accelerating factors and the degradation mechanisms of underground steel rebars from reinforced concrete structures have been investigated. From these studies it emerges that the corrosion of steel rebars from reinforced concrete structures with large dimensions, frequently used in urban infrastructure constructions,

There have been studied the corrosion states of the resistance structures of concrete steel afferent to Bucharest metro's tunnels and galleries, by measuring the reinforcement/wet concrete electrochemical potentials. There have been also measured, by specific electric determinations, DC stray currents which flow through the armature within the concrete as well as the dispersion resistance of railway / concrete armature. From the investigations that

A hybrid high-power solid-state device, voltage limiter and having a fast switching rate, has been conceived and built. The device copes in forward polarization with hazardous overcurrent impulses up to 1800 A for 1s and 120 to 40 A-depending on the type-also for 1s, in reverse polarization. The device was checked at lightning impulses (20/8 μs) at a peak current of 100,000 A. Due to its electric performances (in static, dynamic and switching regimes)