Colliding high energy cosmic rays to the earth atmosphere produces secondary particles which generate EXTENSIVE AIR shower (EAS) that develops in lateral and longitudinal directions. It was found that electron density in two directions is related to the age parameter. Dai et. al. [1] clarified the difference between the lateral and longitudinal age parameters in 1990. However, some scientists believe that the lateral age parameter from NKG model is not sufficient to describe the electro lateral dispersion. In the current study, given the experimental and simulation data and also given the results of Dai et. al. work, the dependence of the lateral and longitudinal age parameter to core distance is investigated. Finally, contrary to NKG theory, at Linsley theory, the age parameter is not a constant parameter, so it increases with an increase in core distance.

In this research, using CORSIKA simulation code with QGSJETII04 and GHEISHA2002d as high and low energy interaction models respectively, proton and iron cosmic ray primaries with 10 17 eV energy and 20-60 o zenith angle are simulated at Tehran observation level (1200m above sea level). By using azimuth angle, arrival time and local coordinates of the muon and electron secondaries as well as rise times of received pulses are calculated. By investigating the rise time as a function of the distance to the Shower Core for different azimuth angle, it is shown that there is an azimuthal asymmetry in the rise time distribution which can be used for mass discrimination of primary cosmic rays.

Deviation angles of secondary electrons and muons in simulated EXTENSIVE AIR SHOWERS were studied. The angles have wide distribution, whose width depends on energy cuts imposed on shower particles. In this work, variation of deviation angles with the energy of secondary particles, shower energy, primary direction, and core distance was investigated. The results put limitations on application of hodoscopic devices in cosmic ray and gamma ray observations.

The first phase of the Alborz Observatory Array (Alborz-1) consists of 20 plastic scintillation detectors each one with surface area of 0. 25 spread over an area of realized to the study of EXTENSIVE AIR SHOWERS around the knee at the Sharif University of Technology campus. The first stage of the project including construction and operation of a prototype system has now been completed and the electronics that will be used in the array instrument has been tested under field conditions. In order to achieve a realistic estimate of the array performance, a large number of simulated CORSIKA SHOWERS have been used. In the present work, theoretical results obtained in the study of different array layouts and trigger conditions are described. Using Monte Carlo simulations of SHOWERS the rate of detected events per day and the trigger probability functions, i. e., the probability for an EXTENSIVE AIR shower to trigger a ground based array as a function of the shower core distance to the center of array are presented for energies above 1 TeV and zenith angles up to. Moreover, the angular resolution of the Alborz-1 array is obtained. For experimental study of the array, Alborz-1 sub-array consists of 5 detectors on a pentagon configuration similar to the central cluster of the Alborz-1 array have been collecting data since 2014 February for 14 month in 4th floor of physics department at Sharif University of Technology. Alborz-I, made of 20 scintillation detectors is set up in a cluster layout to study the cosmic ray spectrum in the energy range of 1012 to 1016 eV. . This paper reveals the zenith angle distribution function of detected AIR SHOWERS by this sub-array.

An 1D hydrodynamic model has been simulation and developed for gas hold-up and liquid circulation velocity prediction in AIR-lift reactors. model is based on momentum balance equations and has been adjusted to experimental data collected on a pilot plant reactor equipped with two types of gas distributors and using water as the liquid phase.The model equations described previously constitute a set of non-linear equations which are solved by an iterative procedure (v.b) (c plus). This model has also been combined with mass transfer and the kinetics of a chemical reaction to yield a complete model of the performance of a reactor.

Alborz observatory is an EAS array in the heights of Alborez mountain chain near Tehran. For the development of the array, more number of detectors is inevitable. The managing the financial resources and achieving the highest efficiency of the array is important for the project. Therefore, Water Cherenkov Detectors has been used for 9 months in the same way as the previous experiment with Scintillation Detectors in a 4-fold square arrangement. After a hardware calibration procedure, the experimental data set was simulated by CORSIKA code and the experimental restrictions were applied over the data set. In this work, the simulation is calibrated with the real experimental results, and it presents a comparable parameter between the experiment and the simulation. The obtained results show that the simulation is in agreement with the experimental results.

Monte Carlo simulation with CORSIKA code using QGSJET hadronic interaction model is applied on more than 5000 cosmic ray primaries to investigate dependence of maximum AIR shower development (Hmax) on mass and energy of, primaries.

Different high energy interaction models are the applied in CORSIKA code to simulate EXTENSIVE AIR SHOWERS (EAS) generated by Cosmic Rays (CR). In this work the effects of QGSJET01, QGSJETII, DPMJET, SIBYLL models on Xmax and multiplicity of secondary electrons and muons at observation level are studied.

Rainfall is the most variable climatic elements. The changes occur in the location and the time dimension in the form of regional climate. The purpose of this study was to investigate the spatial autocorrelation of Iran's heavy and super heavy changes. For this purpose, the daily rainfall data of 664 meteorological stations during the period 1950-2010 have been used. In order to analyze changes in rainfall within a decade, geostatistical techniques such as spatial autocorrelation analysis of hot spots, statistics Getis-Ord Gi along with programming in Matlab environment and the Surfer and the GIs were used. The results of this study indicated that the Caspian coast, North West and West along the western foothills of the Zagros Mountains of Iran, the inner regions of Iran and southern parts of South East and North East of Iran had the highest precipitation of heavy and super heavy requirements. Spatial pattern of heavy precipitation showed that the maximum positive spatial autocorrelation pattern of heavy precipitation, despite their different periods of oscillation, but includes areas of West, North West and West coast of the Caspian Sea. While this is a negative spatial autocorrelation pattern of heavy precipitation, it is observed frequently in central Iran and parts of the East, particularly in Zabul. Patterns of heavy precipitation are similar to heavy precipitation.