فهرست مطالب اصغر توکلی

Wind erosion is one of the most important natural processes in arid and semi-arid areas, occurring as a result of erosive winds. Wind speed, frequency and duration should be considered in studies related to wind erosion. Kashan Erg is one of the most important sand dunes complexes in Iran. To study the relationship between the wind characteristics (Uni- directional index, windness index, wind duration and frequency) with Erg morphology and also study the changes of sand flow rate in various regions, anemometers data were obtained from synoptic stations of Kashan, Ardestan, Jangalbani Badrod, Garmsar and Qom. Then, the interpolation map of sand transport and interpolation map of average and maximum wind in Kashan Erg were drawn using GIS software. Finally, the analysis results showed that the interpolation map of sand transport corroborated the results obtained from interpolation map of average wind, because sand transport rate and average wind speed were reduced from east to west of the Erg. Therefore, it is found that wind frequency and duration have more important role in the sand transport and morphology of the study area as compared with the wind speed. In addition, the comparison of Erg morphology and anemometer results in different stations showed that the spring and summer winds had the highest role in the Erg morphology.

The Tor network is one of the most useful and popular anonymity systems used on the web. This network works with bandwidths which volunteers provide from all around the world. By increasing the importance of security issues, surfing on the web anonymously in recent years attracted many users to Tor network and therefore it has been under a lot of research studies. Many of these studies have been implemented as attacks and in many cases the research itself also offers a solution for the problem too. Other important issue is bypassing filtering of internet in many countries by using Tor. It is a reason to filter Tor in these countries. In this paper we first review Tor network structure and then we categorize and explain attacks which are applied on the network. Finally we introduce how the network has been blocked in some countries and we also explain how Tor counteracted these filtering techniques.

This paper describes the synthesis of barium copper silicate using agglomeration of BaD, CuD, SiOz and borax. The synthesized pigments were then investigated by using X-ray diffraction (XRD) and scanning cleeton microscopy (SEM) techniques. The alkaline oxides, earth alkaline oxides, etc. can reduce the intensity of XRD lines of the samples. In order to confirm the existence of barium copper silicate pigments, the blue and purple glazes were sythesized and their X-ray diffraction lines were then investigated and compared to those for the ancient glazes.