Khavaran Institute of Higher Education
Mashhad, Iran
Time filter
Source Type

Bina K.,Khavaran Institute of Higher Education | Saghi H.,Hakim Sabzevari University
Experimental Thermal and Fluid Science | Year: 2017

Bottom racks have been widely used in dam-less projects as a means to divert some part of the river flow. Mesh-panel bottom rack is a new form of bottom rack which is introduced in this paper and consists of longitudinal bars along the river over transverse bars perpendicular to the river flow. Deformation of mesh-panel racks under static and dynamic loads is less than other kinds of bottom intakes. In the present study, firstly, physically-based relationships were derived for rack discharge coefficients in sediment and non-sediment flows. To do this, three mesh-panel racks were built, and the effects of hydraulic characteristics of approaching flow, rack geometry (slope, length, bar shapes), and sediment characteristics on discharge coefficient were investigated, and, also, a sensitivity analysis was taken. The data was obtained from a series of tests carried out in a laboratory flume equipped with inclined bottom rack and a sediment chamber at the upstream. For each run, diverted and remaining discharges were measured by two separate fully-aerated sharp crested rectangular weirs. Secondly, trap ratio of mesh-panel rack which was defined as the weight of passed sediment through the mesh panel to the total input amount of sediment at upstream, were experimentally studied and discussed. Finally, a physically-based dimensionless relation for estimating trap ratio was presented, and sensitivity analysis was done. © 2017 Elsevier Inc.

Golmakani A.,Khavaran Institute of Higher Education | Golmakani A.,Abdus Salam International Center For Theoretical Physics | Homburg A.J.,University of Amsterdam
Dynamical Systems | Year: 2011

Lorenz-like attractors are known to appear in unfoldings from certain codimension two homoclinic bifurcations for differential equations in ℝ3 that possess a reflectional symmetry. This includes homoclinic loops under a resonance condition and the inclination-flip homoclinic loops. We show that Lorenz-like attractors also appear in the third possible codimension two homoclinic bifurcation (for homoclinic loops to equilibria with real different eigenvalues); the orbit-flip homoclinic bifurcation. We moreover provide a bifurcation analysis computing the bifurcation curves of bifurcations from periodic orbits and discussing the creation and destruction of the Lorenz-like attractors. Known results for the inclination flip are extended to include a bifurcation analysis. © 2011 Taylor & Francis.

Abbassi S.,Damghan University | Abbassi S.,Institute for Research in Fundamental Sciences | Ghanbari J.,Ferdowsi University of Mashhad | Ghanbari J.,Khavaran Institute of Higher Education | Ghasemnezhad M.,Ferdowsi University of Mashhad
Monthly Notices of the Royal Astronomical Society | Year: 2010

We examine the effects of a hydrodynamical wind on advection-dominated accretion flows (ADAFs) with thermal conduction in the presence of a toroidal magnetic field under a self-similar treatment. The disc gas is assumed to be isothermal. For a steady state structure of such accretion flows a set of self-similar solutions are presented. The mass-accretion rate decreases with radius r as Ṁ α rs+1/2, where s is an arbitrary constant. We show that existence of wind will lead to an increase of the accretion velocity. Cooling effects of outflows or winds are noticeable and should be taken into account for calculating luminosity and effective temperature of optically thin and thick ADAFs. Increasing the effect of wind decreases the disc's temperature because of energy flux which is taken away by winds. We will see that for a given set of input parameters, the solution reaches a non-rotating limit at a specific value of φs. The values of this limitation on φs will increase by adding s, the wind parameter. In fact, the higher values of s will allow the disc to have a physical rotating solution for larger φs. © 2010 The Authors. Journal compilation © 2010 RAS.

Amraei E.,Khavaran Institute of Higher Education | Mobasheri M.R.,K. N. Toosi University of Technology
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives | Year: 2014

CCD Camera is a multi-spectral sensor that is carried by CBERS 2 satellite. Imaging technique in this sensor is push broom. In images acquired by the CCD Camera, some vertical striping noise can be seen. This is due to the detectors mismatch, inter detector variability, improper calibration of detectors and low signal-to-noise ratio. These noises are more profound in images acquired from the homogeneous surfaces, which are processed at level 2. However, the existence of these noises render the interpretation of the data and extracting information from these images difficult. In this work, spatial moment matching method is proposed to modify these images. In this method, the statistical moments such as mean and standard deviation of columns in each band are used to balance the statistical specifications of the detector array to those of reference values. After the removal of the noise, some periodic diagonal stripes remain in the image where their removal by using the aforementioned method seems impossible. Therefore, to omit them, frequency domain Butterworth notch filter was applied. Finally to evaluate the results, the image statistical moments such as the mean and standard deviation were deployed. The study proves the effectiveness of the method in noise removal.

Mobasheri M.R.,K. N. Toosi University of Technology | Zendehbad S.A.,Khavaran Institute of Higher Education
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives | Year: 2013

The CHRIS sensor on the PROBA-1 satellite has imaged as push-broom way, 18 meter spatial resolution and 18 bands (1.25-11 nm) spectral resolution from earth since 2001. After 13 years of the life of the sensor because of many reasons including the influence of solar radiation and magnetic fields of Earth and Sun, behaviour of the response function of the detector exit from calibration mode and performance of some CCDs has failed. This has caused some image information in some bands have been deleted or invalid. In some images, some dark streaks or light bands in different locations need to be created to identify and correct. In this paper all type of noise which likely impact on sensor data by CHRIS from record and transmission identified, calculated and formulated and method is presented through modifying. To do this we use the In-fight and On-ground measurements parameters. Otherwise creation of noise in images is divided into horizontal and vertical noise. Due to the random noise is created in different bands and different locations, those images in which noise is observed is used. In this paper, techniques to identify and correct the dark or pale stripe detail of the images are created. Finally, the noisy images were compared before and after the reform and effective algorithms to detect and correct errors were demonstrated.

Vahidi H.,Khavaran Institute of Higher Education | Monabbati E.,Ferdowsi University of Mashhad
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives | Year: 2013

The main idea of this paper is to integrate the non-contextual support vector machines (SVM) classifiers with Markov random fields (MRF) approach to develop a contextual framework for monitoring of agricultural land cover. To this end, the SVM and MRF approaches were integrated to exploit both spectral and spatial contextual information in the image for more accurate classification of remote sensing data from an agricultural region in Biddinghuizen, the Netherlands. Comparative analysis of this study clearly demonstrated that the proposed contextual method based on SVM-MRF models generates a higher average accuracy, overall accuracy and Kappa coefficient compared with non-contextual SVM method. Since the spatial information is considered in the proposed method, this study indicates that a neater, more homogonous and speckle-free results could be generated by the SVM-MRF approach.

Ghafarian T.,Khavaran Institute of Higher Education | Javadi B.,University of Western Sydney
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013

One of the main challenges in volunteer computing systems is scheduling large-scale applications expressed as scientific workflows. This work aims to integrate partitioning scientific workflows and proximity-aware resource provisioning to increase the percentage of workflows that meet the deadline in peer-to-peer based volunteer computing systems. In the partitioning phase, a scientific workflow is partitioned into sub-workflows in order to minimize data dependencies among them. We utilize knowledge-free load balancing policy and proximity of resources to distribute sub-workflows on volunteer resources. Simulation results show that the proposed workflow scheduling system improves the percentage of scientific workflows that meet the deadline with average of 18% under a moderate workload. © Springer International Publishing Switzerland 2013.

Mobasheri M.R.,oosi University of Technology | Shirazi H.,Khavaran Institute of Higher Education
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives | Year: 2015

This article aims to increase the accuracy of Ozone data from tropospheric column (TOC) of the OMI and TES satellite instruments. To validate the estimated amount of satellite data, Ozonesonde data is used. The vertical resolution in both instruments in the tropospheric atmosphere decreases so that the degree of freedom signals (DOFS) on the average for TES is reduced to 2 and for OMI is reduced to1. But this decline in accuracy in estimation of tropospheric ozone is more obvious in urban areas so that estimated ozone in both instruments alone in non-urban areas show a high correlation with Ozonesonde. But in urban areas this correlation is significantly reduced, due to the ozone pre-structures and consequently an increase on surface-level ozone in urban areas. In order to improve the accuracy of satellite data, the average tropospheric ozone data from the two instruments were used. The aim is to increase the vertical resolution of ozone profile and the results clearly indicate an increase in correlations, but nevertheless the satellite data have a positive bias towards the earth data. To reduce the bias, with the solar flux and nitrogen dioxide values and surface temperatures are calculated as factors of ozone production on the earth's surface and formation of mathematical equations based on coefficients for each of the mentioned values and multiplication of these coefficients by satellite data and repeated comparison with the values of Ozonesonde, the results showed that bias in urban areas is greatly reduced.

Ahanj A.,Khavaran Institute of Higher Education | Ahanj A.,Institute for Research in Fundamental Sciences | Kunkri S.,Mahadevananda Mahavidyalaya | Rai A.,se National Center For Basic Science | And 2 more authors.
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2010

Recently, the principle of nonviolation of information causality has been proposed as one of the foundational properties of nature. We explore the Hardy's nonlocality theorem for two-qubit systems, in the context of generalized probability theory, restricted by the principle of nonviolation of information causality. Applying a sufficient condition for information causality violation, we derive an upper bound on the maximum success probability of Hardy's nonlocality argument. We find that the bound achieved here is higher than that allowed by quantum mechanics but still much less than what the no-signaling condition permits. We also study the Cabello type nonlocality argument (a generalization of Hardy's argument) in this context. © 2010 The American Physical Society.

Alamatian E.,Khavaran Institute of Higher Education | Jaefarzadeh M.R.,Ferdowsi University of Mashhad
International Journal of Civil Engineering | Year: 2012

In this article, the two-dimensional depth-averaged Saint Venant equations, including the turbulence terms, are solved in a supercritical flow with oblique standing waves. The algorithm applies the finite volume Roe-TVD method with unstructured triangular cells. Three depth-averaged turbulence models, including the mixing length, k-ε and algebraic stress model (ASM), are used to close the hydrodynamic equations. The supercritical flow in a channel downstream from a side-baffle in plan is then simulated, and the numerical results are compared with the data obtained from a laboratory model. The application of different models demonstrates that the consideration of turbulence models improves the results at the shock wave positions. The qualitative study of the results and error analysis indicates that the ASM offers the most desirable solutions in comparison with the other models. However, our numerical experiments show that, amongst the source term components, the negligence of turbulence terms produces the least error in the depth estimation in comparison with the removal of the bed slope or bed friction terms.

Loading Khavaran Institute of Higher Education collaborators
Loading Khavaran Institute of Higher Education collaborators