Distinguish between heterogeneity and anisotropy effects are appropriate method to achieve accurate resistivity data interpretations. Since the anisotropy effects are weaker than INHOMOGENEITY one so, we have to use a technique that is sensitive to anisotropy for removing heterogeneity effects.Azimuthal resistivity surveys increasingly are being used by hydrogeologists in the dentification and characterization of fractured rocks. It also can be used to detect anisotropy. The Arrow-Type array that we investigated here does show the highest sensitivity to anisotropy and can remove effects of near surface inhomogeneities. It also can distinguish between anisotropy and INHOMOGENEITY as well. On the other hand, using a simpler logistic in the field will make this method more convenient in comparison with the other azimuthal arrays. Knowing exact place and direction of anisotropy helps us to achieve accurate interpretation; in addition it gives us convenient geological information. In this paper the Arrow-type array is determined first. We used this array in the field work to detect heterogeneities’ exact locations and to remove their effects on our data. We were able to obtain pure data for anisotropy investigation.

We introduce a new method of measuring transmit and receive RF INHOMOGENEITY in different RF coils of MRI systems. In this method a single slice of a uniform phantom is imaged from different flip angles, using a standard spin echo protocol. The signal intensity in these images is then fitted to a mathematical model which describes the relationship between the signal intensity and flip angle of the spin echo images. The results of this curve fitting process are two parameters, T(r) and R(r), whose variation with the spatial position shows RF transmit, and receive non-uniformity, respectively. In this approach a linear profile of B1 field distribution and receive sensitivity of RF coils are achieved which is also applicable in vivo. The method can be used to assess any commercial MR scanner and is highly recommended for the quality control (QC) of those MR scanners which are devoid of complicated protocols such as SEθ-2 θ. Such systems are still running in different clinics especially in the developing countries where the latest high performance MR scanners are not available and many scanners lack standard maintenance services.

This paper presents the laboratory results of the effect of INHOMOGENEITY of concrete quality in initiation period of corrosion and rate of corrosion of reinforcement. Two types of reinforced concrete including columns and slabs were investigated. Each specimen was made of two different concrete qualities by changing water-cement ratio. Specimens were subject to a series of laboratory tests, including corrosion potential, rate of corrosion and resistivity. The results showed that INHOMOGENEITY of concrete quality is an important factor in reducing of initiation time of corrosion and increasing rate of corrosion. Direction of reinforcement and direction of pouring concrete are important parameters, which have effects on potential differences in two parts of the reinforced concrete members. In other words, duration of initiation corrosion was less in columns compared to that of slabs, due to differences in direction of reinforcement.

Background and Objective: Biological SOIL crusts are a collection of lichens, mosses, fungi, cyanobacteria, etc. that are part of the SOIL ecosystem. Estimation of density and distribution of biological SOIL crusts in arid and semi-arid regions of Iran, which is the subject of SOIL erosion and wastage is very important. Methods based on remote sensing techniques are important in terms of cost and time less efficient methods to achieve this goal. Segzi plain is one of the critical points of wind erosion in Iran and identifying and determining the distribution of biological SOIL crusts as a SOIL modifier is an effective step in reducing wind erosion in the region. In this research, BSCI (Biological SOIL Crust) index has been used to prepare the distribution map of lichen-dominated biological SOIL crusts. Materials and Methods: The study area is part of the Sajzi Desert (Central Deserts of Iran) which is located in Isfahan province of Iran. The study area with an area of 199. 5 hectares is spread between the eastern lengths of 51o52'32" to 52o27'41" and the northern widths of 32o33'31" to 32o55'01". The average slope of Segzi plain is 1. 08 percent and its average height is 1680 meters. According to the statistics of East Isfahan Meteorological Station (Shahid Beheshti Station), the average annual rainfall in the region is 106 mm. According to the Dumarten climatic classification, the climate of the region is dry and according to the Amberge classification it is cold. The BSCI index is a combination of the relationships used to estimate vegetation and bare SOIL surface, and its mathematical relationship is the slope of the SOIL line. To calculate the SOIL line in an area, one must first separate the pixels that have bare SOIL and no vegetation. In order to calculate the SOIL line equation, in four seasons of a year, images of Landsat OLI 8 satellite related to 2018 were downloaded from the site of the US Geological Survey and 20 to 30 pixels of pure bare SOIL were extracted by drawing the reflection values of these pixels in the red and infrared band. Red near SOIL line coefficients were calculated for each season in the Segzi Plain. Based on BSCI index, lichen-dominated biological SOIL crust are identified using at least VIS-NIR spectral reflection and the slope between the red and green bands compared to bare SOIL and dry vegetation. Using ENVI software, the distribution shells of biological shells with lichen dominance were prepared in four seasons since 2018 in Segzi plain. Then, the prepared maps were validated based on land points and the total accuracy and kappa index were calculated in all four seasons. The collected lichen samples were identified based on their morphological characteristics and using a stereomicroscope, conventional microscope and common color reagents such as potassium hydroxide (KOH). After applying the BSCI index on the Landsat OLI 8 satellite image, using ENVI software, spectral profiles related to 4 points of Segzi plain in four seasons of the year were prepared and the spectral reflection in four seasons of the year in different points were examined. Results and Discussion: The slope of the SOIL line is lower in the rainy season, which coincides with the growth of herbaceous and annual plants, compared to the summer season, which has the least amount of rainfall, and the annual plants have dried up and become extinct. In May, the slope of the SOIL line was minimal (0. 39) and in late summer it has its maximum value (0. 78). In fact, the slope of the SOIL line has decreased from mid-August to May, and then has increased with the loss of annual vegetation and the increase of bare SOIL surface. The distribution maps of bio-shells in all four seasons of the year were validated during field visits and the year it was found that the highest accuracy of the map related to the map produced from Landsat 8 image is related to summer with 94% total accuracy and Kappa index equal to 0. 7412. Interpretation of the spectral profiles of the BSCI index shows that the reflections of the spectra related to the zephyr and strain prepared on the lichen dispersion points are very close to each other and also the spectral profiles of the mid-autumn and early spring are quite consistent. Whereas in the faults, which did not cover the biological crust, the amount of reflection was higher and there was a slight difference between the reflection diagrams of autumn and spring. Although the reflectance values of a range of agricultural lands and the distribution points of biological crusts are very close to each other, the spectral diagrams of all four seasons are very different from each other. But in all seasons of the year and in all places, the least reflection has occurred in the beginning of winter and the most reflection has occurred in summer. The climate of Segzi plain is Mediterranean and precipitation occurs in the cold season of the year. Simultaneously with the increase of precipitation from the middle of autumn, annual plants and mosses at the base of shrubs begin to grow and reach their peak in early winter and again at the beginning of spring. Decreases in rainfall have reduced their density. If the winter spectrum has the least reflection in all places. While in late summer, when the annuals and mosses have dried up, it has had the greatest spectral reflection. In Fasaran, which is a barren area and a landfill, it has shown its maximum reflection. Therefore, the BSCI index relative to the percentage of organic matter has a significant error in the detection of biological SOIL crust and where the organic matter is high may not provide accurate diagnosis of SOIL bioshells. Of course, since the BSCI index is defined for the detection of throat compounds in lichen tissues. The error rate for organic matter is reduced to a minimum. As it has been observed in the final map, there is no cover of biological SOIL crusts in Fasaran and only SOIL biological crusts are observed in the areas around Fasaran in the agricultural areas. In agricultural areas, due to human intervention and cultivation, the amount of annual plants is different from the field of natural resources in different seasons of a year have become. Conclusion: Spectral similarity of the most important SOIL surface, including vegetation, the involvement of human factors in increasing or decreasing SOIL organic matter, bare SOIL, etc. limits the efficiency of the BSCI index and therefore in the time period of satellite images and regional conditions have a great impact on It has the accuracy of BSCI index.

In this study, the effect of geometrical parameters of rectangular vortex extrusion die, including twist angle (𝜑 ), reduction in area (𝑅 𝐴 ), and twist zone length (𝐿 ), on deformation INHOMOGENEITY is investigated using the finite element analysis and response surface methodology. Analysis of variance (ANOVA) was used to determine the primary parameters and accuracy of the mathematical model obtained from response surface methodology results. The results showed that the suggested mathematical model predicts the strain INHOMOGENEITY with high accuracy. Additionally, it revealed that the input parameters of 𝜑 , 𝑅 𝐴 , 𝐿 , the interaction between 𝜑 and 𝑅 𝐴 (𝜑 × 𝑅 𝐴 ), and interaction between 𝑅 𝐴 and 𝐿 (𝑅 𝐴 × 𝐿 ) are the main significant factors affecting the INHOMOGENEITY. Perturbation plots and 3D surface diagrams were used to check the results of ANOVA, the sign, and the magnitude of the coefficient of the suggested mathematical model.

Aerosol filtration in fibrous filters is one of the principal methods of removal of solid particles from the gas stream. The classical theory of depth filtration is based on the assumption of existing single fiber efficiency, which may be used to the recalculation of the overall efficiency of the entire filter. There are several reasons for inappropriate estimation of the single fiber efficiency including the assumption of the negligible effect of the presence of neighboring fibers and perpendicular orientation of the homogenous fibers. This work aims to investigate the influence of mesoscale INHOMOGENEITY on fibrous filter performance using Computational Fluid Dynamics in models of filters differed by internal structure.

Facilities built in areas affected by earthquake activity, such as tunnels, which have always been an integral part of human life, must withstand both dynamic and static loading. It has led to the need for practical studies on the effects of earthquakes on underground structures and the factors affecting their destruction. For this purpose, in this research, at first different patterns of tunnel’s excavation were investigated and by using Plaxis 2D software and based on Tabas earthquake in Iran, sensitivity analysis on geotechnical parameters of the SOIL surrounding tunnel such as cohesion, friction angle, unit weight and modulus of elasticity was carried out, and the parameters whose changes have the greatest and least effects on the bending moment changes on the tunnel lining are introduced. The results show that tunnel excavation patterns significantly affect the bending moment, axial forces, displacements, and surface settlement of the tunnel. Often, by dividing tunnel excavation area to small parts, the values of bending moment, axial forces, displacements, and surface settlement of the tunnel decreases in static analysis. Also, outputs of sensitivity analysis on geotechnical parameters of the SOIL surrounding tunnel showed that modulus of elasticity of the SOIL surrounding tunnel has the most effect and cohesion changes have the least effect on bending moment induced on tunnel lining..