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Aims: Producing a land use/land cover map is a fundamental step in different studies. This study aimed to assess the ability of hierarchical, pixel-based and object-oriented classification methods to produce land use/cover maps.
Materials & Methods: This study was conducted in the Harat-Marvast basin of Yazd Province, Iran using Landsat imagery of 2016 (paths 161 and 162, row 39). The hierarchical image classification method was tested for land use/cover mapping. A statistical comparison between three algorithms, namely pixel-based, object-oriented and hierarchical image classification was performed using the McNemar test. An intensive field survey was also accomplished to obtain training and test samples.
Findings: The kappa coefficients for pixel-based, hierarchical and object-oriented techniques were 0.76, 0.83 and 0.94, respectively. Results also showed that the performance of SVM and hierarchical algorithms are significantly different with aχ²f 112.3 which shows the superior performance of the hierarchical algorithm.
Conclusion: It was shown that the object-oriented approach performed significantly better than the two above-mentioned methods (χ²= 149.6). As the computational costs of object-oriented methods are relatively high, the hierarchical algorithm can be suggested when there are limitations in time or computational infrastructures. Therefore, the hierarchical algorithm can be used instead of simple pixel-based algorithms for land use/cover mapping.

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Hydraulic fracturing as a method for reservoir stimulation depends on the properties of the media that fracture propagates in it. Discontinuities in the media and their mechanical properties greatly affect the geometry and propagation of hydraulic fractures. In this research, the interaction between the hydraulic fractures with the media layers interface, fracture propagation pattern and termination in multi-layered media were investigated. The true tri-axial cell was utilized to conduct experimental tests on cube multi-layered samples with discontinuities. The tests were aimed to investigate propagation of fractures from soft to stiff, stiff to soft media and also the effect of elastic properties of rocks in hydraulic fracturing. Results showed that the condition of discontinuities (healed, open or filled) and elastic properties of the layers influences the geometry and propagation pattern of hydraulic fractures. In the block with the bounded interfaces, the fracture propagates and interacts with the interfaces, then penetrates in the adjacent layers. However, for the block with unbounded interfaces the fracture propagates from the borehole up to the interface, then after filling the interface with the fluid the new fracture will propagate in the adjacent blocks. In sample where the interface was filled, the fracture propagation was terminated and then the fluid started to leak off in the interface. The results also show when the fracture reaches the interface, the pressure increased immediately and more pressure is needed for fracture propagation across the interface. In comparison between the length and width of fractures in soft and stiff layers, the study displays that the fracture width and its penetration length in soft layers are greater than those in stiff layers.

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Abstract: Hydraulic fracturing as a method for reservoir stimulation depends on the properties of the media that fracture propagates in it. Discontinuities in the media and their mechanical properties greatly affect the geometry and propagation of hydraulic fractures. In this research, the interaction between the hydraulic fractures with the media layers interface, fracture propagation pattern and termination in multi-layered media were investigated. The true tri-axial cell was utilized to conduct experimental tests on cube multi-layered samples with discontinuities. The tests were aimed to investigate propagation of fractures from soft to stiff, stiff to soft media and also the effect of elastic properties of rocks in hydraulic fracturing. Results showed that the condition of discontinuities (healed, open or filled) and elastic properties of the layers influences the geometry and propagation pattern of hydraulic fractures. In the block with the bonded interfaces, the fracture propagates and interacts with the interfaces, then penetrates in the adjacent layers. However, for the block with unbonded interfaces the fracture propagates from the borehole up to the interface, then after filling the interface with the fluid the new fracture will propagate in the adjacent blocks. In sample where the interface was filled, the fracture propagation was terminated and then the fluid started to leak off in the interface. The results also show when the fracture reaches the interface, the pressure increased immediately and more pressure is needed for fracture propagation across the interface. In comparison between the length and width of fractures in soft and stiff layers, the study displays that the fracture width and its penetration length in soft layers are greater than those in stiff layers.

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In this study, the radial flow turbine of a cooling turbine is investigated numerically and then compared with the experimental results at some operation conditions. Performance characteristics of the compressor are obtained experimentally by measurements of rotor speed and flow parameters. In this investigation, the turbine performance curve is obtained and three dimensional flow field in the turbine is analyzed. The rotor and casting geometry are modeled in BLADE GEN and CATIA softwares respectively. The TURBO GRID software is used for grid generation of rotor while the ANSYS MESH software is applied for grid generation of casting. Finally, 3D numerical solution of fluid flow in the turbine is solved by CFX flow solver. In this approach, compressible flow equations are solved according to the pressure based method with SST turbulence model. To ensure the numerical results, the grid independency is studied. Finally, the performance characteristics of the turbine are obtained numerically which are then compared to the experimental results. The comparison shows good agreement between numerical and experimental results.

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Anthracnose caused by Colletotrichum gloeosporioides s. l. is one of the most important diseases of citrus in northern Iran. To study the genetic structure of C. gloeosporioides s. l. from citrusspp., infected samples were collected from three citrus cultivating regions of northern Iran, during the summer of 2009. Fifty one monoconidial isolates were used as the objective of REP- and BOX-PCR fingerprintings. Eight fingerprinting groups were observed in the constructed phenogram. The largest proportion (94.37%) of total genetic diversity (H_t) was attributed to diversity within populations (H_s). Estimates of Nei’s genetic similarity and distances exhibited the high level of similarity among three populations. The value of gene flow, N_M= 8.4, indicates that there is low limitation to gene flow among these geographically distant populations, which make these groups genetically homogenous. The results indicate that the three geographic populations are not developing independently and can be part of a Mega-population. Forty three isolates were divided into 19 groups in the phenogram constructed by combination of morphological characteristics data. Estimation of correlation between morphologic and rep-PCR matrixes indicated a weak and non-significant correlation between morphology and rep-PCR haplotypes (r= 0.2, P= 0.992). Fifty one isolates were examined to clarify their sexual behavior. Eight isolates were identified as homothallic and 14 successful outcrosses were observed among self-sterile isolates.

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In axial flow compressor there is a gap between stationary and rotating members since the stator vane is fixed at the casing and the shaft is rotating at the root. Also, the pressure increases when the air flows through the stator vanes. Therefore, due to pressure increase and existence gap under vanes, the leakage is inevitable in the stator tip. This leakage can change the flow pattern near the stator tip, which causes more separation. Therefore the loss has been increased so it adversely effects on performance. In this paper, the effect of stator tip sealing with honeycomb on compressor performance is investigated. For this purpose, the 9th stage of a ten-stage compressor is examined in two cases of solid wall and sealing with honeycomb. The numerical results have good agreements with experimental results. The results show that by reduction of leakage at stator tip, the size and depth of tip corner separation decreased significantly leading to loss reduction. Also the effect of the leakage on flow angles shows that to have more accurate analysis of compressor performance, it is necessary to be considered the stator tip leakage. On the other hand, according to same effect of honeycomb on reducing stator tip leakage than solid wall, here the honeycomb roles as an abradable material to prevent direct contact between rotor and stator. Also in analysis of stage the honeycomb can be replaced with solid wall model.

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Glassmaking traces its history back to antiquity as is the case with several other crafts in Iran. The craft would culminate under the Sassanian rule, when an assortment of receptacles in different sizes, shapes, and functions came into popular use. The present study examines a sample of 29 pieces of Sassanian glass objects preserved in the Sanandaj Archaeological Museum. Deriving from clandestine excavations, no previous research has investigated these pieces. This descriptive and historical-analytical study draws upon comparisons with related museum objects and library research. The questions are: Which excavated sites in the Sassanian territory are to be examined for comparanda? What are the manufacturing techniques of the objects in question? To which part of the Sassanian time span do they date? What are the common forms as well as their functions and decorations? The sample appears to compare with the material from Mesopotamia (Tell Mahuz, Abu Skhair, Barghuthiat, and Kish) and Veh Ardashir, which were major centers of glass production at the time. The pieces were manufactured in free-blowing and mold-blowing techniques. Bowls are the common form, followed by bottles, unguentaria, juglets, and jars for ritual, cosmetic, and practical functions. The major decorations detected on the study sample include applied trails and facet cutting. The pieces can be assigned to two consecutive chronological extents: The first spans the onset of the Sassanian period (2nd century AD) to the 4th century AD, and the second encompasses the 4th century AD to the demise of the empire. Dispersion of such objects across the Sassanian Empire suggests that glassware represented a trade item at that time.