a. khodaei

Improving and optimizing corrosion protection methods, including cathodic protection, has received much attention in recent years. Due to the advancement of science and technology and industry development, manufacturing and controlling rectifiers has also made significant progress. The performance characteristics and efficiency of rectifier components have improved over the years. Based on the studies, an industrial pulse rectifier that can produce pulsed current in the frequency range of 800 Hz to 60 kHz based on the desired frequency and duty cycle was successfully designed and manufactured. In order to evaluate the protection performance of this system in the field, the pulse rectifier was placed next to the conventional rectifier, and the protection conditions of the system were continuously monitored. Three test points with specified intervals were analyzed at frequency and duty cycle of 50 kHz and 73% (A), 60 kHz and 73% (B), 60 kHz and 50% (C), and 50 kHz and 50% (D), respectively. Results showed that AC voltage in the pulse system has decreased by more than 80% compared to the conventional system. In addition, the current consumption values showed that in the pulse system, the current consumption has decreased by more than 70% in certain values of frequency and duty cycle. Because the pulse wave has practically no current consumption during off time, energy consumption is greatly reduced, an important factor in energy consumption and economic costs. Also, this system has no cooling system like the conventional rectifiers. Accordingly, the system has a better performance at certain values of frequency and duty cycle. Such systems in areas with high electrolyte resistance can be considered a good option. Also, if the pipeline has a cover, the system can function properly even with the cover separation areas. Moreover, the protection potential became more uniform and remained within the protection range during the measurement period, despite the poor performance of the anode bed.

The use of asphalt in paving BRT lines in Tehran, due to heavy axial loads of passing vehicles and heavy braking force caused by these vehicles, has led to various pavement failures such as reflective cracks, grooves, shrinkage, longitudinal and transverse cracks. In this paper, a model of conventional concrete pavements is compared with models of new materials such as fibrous concrete, permeable concrete and fiber permeable concrete using Abaqus and Kenpave software in paving BRT lines in Tehran. Laboratory results have been used to calibrate the modeling parameters. At the end of the article, the effect of repetitive loading on tensile fatigue behavior in concrete models is discussed. To generalize the results, light cargo and A380 aircraft were also used. Compressive, tensile, deformation, and von Mises stress diagrams were obtained by applying these loads to models with a thickness of 5, 10, 15, 20, and 25 cm. The results showed that by controlling the tensile and compressive stresses applied on the surface and also applying one million loading cycles on it, all the mentioned materials can be used in road pavement and fiber concrete in airport pavement.

Our concern is with the image of the west in the first Iranian travelogues. How Elements which shape the west image in these travelogues are assembled? Where is their origin? How they interact with each other and were narrated? The contemporary image of the west is an over-determined and dreamlike image-narration. By relying on concepts such as over determination, different histories, elements, and moments, we try to suggest an interpretation about the structure of west narration in primary Iranian travelogues. Our research suggests the idea of the west, in mystical and Sufi doctrine, represents a sequence of association: material-body-darkness-descend-temptation-guilt-accident. The idea of the east associates the opposite side of sequence: sprit-gust-light-ascend-certainty-virtue-essence. These sequences of associations are preconditions of visibility which the first travelogues experience the geopolitical west. Our research about the origins of the narrative structure of travelogues about the west suggests that synthesis of the colonial and the mystical thoughts create a special narration about the east-west relation. East is the ascending arc and west is the descending arc. This image of east-west relation is one of the main assumptions of orientalism.