This paper presents a new approach for design of the log-periodic dipole array antenna (LPDA) based on using of different design parameters in the LPDA elements to control the antenna behavior. In the proposed procedure, the design parameters can control the value of forward gain over the operating frequency range, and also adjust the gain flatness. Furthermore, this design procedure can decrease the LPDA dimensions in comparison to the conventional design. Based on the proposed design method, several LPDA antennas are designed and simulated numerically by the method of moment. The simulation results show that this LPDA design procedure can be a good candidate for design of optimized antenna in different frequency bands.

This paper proposes a fundamental approach for radiation pattern correction of the mutually coupled circular dipole antenna array (CDAA) using parametric assimilation technique. The effect of mutual coupling is an indispensable part of any practical design issue of the antenna array. Many analytical and numerical techniques have been put forward in the past few decades for the calculation, compensation and reduction of mutual coupling effect. This paper shows an accurate method for mutual coupling correction by using a recently proposed technique called parametric assimilation technique, where the values of mutual impedance are calculated and assimilated with the values of the desired radiation pattern. The proposed technique is cost-effective, less complicated and easy to implement while achieves better performance for mutually coupled circular dipole antenna array synthesis. Grey Wolf Optimization (GWO) algorithm is a state-of-the-art stochastic algorithm applied here to find the optimal values of the current excitation weights and the inter-element spacing between each element of the CDAA for the desired, uncorrected and corrected far-field radiation pattern synthesis. PSO and DE optimization-based statistical results are also reported to compare the results obtained by using GWO algorithm to confirm the outstanding performance of GWO algorithm based design.

To determine the probability of sewage infiltration into foundations of unborn structures, the Werner and the dipole - dipole arrays were used in an electrical resistivity tomograph operation in Masjed Soleiman City which is located in south west of Iran. Using Robust Constraint and Combined Marquardt and Occam algorithms, the measured apparent data were inverted to true electrical resistivity values separately then joint inversion was carried out using the data gathered by both arrays. Three drilled boreholes along the electrical resistivity profile were very useful in accurate interpreting the results. The Combined Marquardt and Occam algorithm provided better results than the Robust Constraint for presenting a subsurface electrical resistivity mode. Also, the electrical resistivity model resulting from the joint inversion of the Werner and dipole - dipole array data is more consistent with reality than the individual inversion of the data for each array.Keywords: Wenner, dipole-dipole, electrode array, Joint inversion, electrical resistivity.

Sharifabad copper deposit is located on the Cenozoic volcanic belt in the northwest of Bardeskan, Khorasan Razavi Province. The host rocks of the mineralization are pyroxene andesite, tuff, agglomerate, limestone, sandstone, and micro conglomerate of the volcanic rocks of Eocene and Oligocene age. Alteration includes propylitic, silica and carbonate materials. Mineralization is restricted to the veins and veinlets and is controlled by the local faults. Mineralization mainly consists of chalcosite, magnetite, hematite, pyrite and malachite that occur in the cavities and fractures of the host rocks. Geophysical surveys using resistivity (Res) and induced polarization (IP) methods have been carried out along 5 survey lines. The results indicate high resistivity and IP values in the depth levels of 0-25 and 32-49 meters, and thus, relevant highly resistant horizons are identified. On the basis of the geological and geophysical studies in the area, eight locations for drilling exploration boreholes are proposed that probably contain highly concentrated copper mineralization. Introduction The Sharifabad copper deposit is situated in the Sabzevar zone and Eastern Iran Cenozoic volcanic rocks. The area is covered by a detailed exploration program, which includes preparation of the geological map of the area at 1: 5, 000 scale, and drilling several hundred meters of trenches. This study focuses on the copper bearing veins system and determination of subsurface mineralization by conducting geological and geophysical operations. For carrying out geophysical operations, 5 survey lines have been designed, and then, surveyed in the area. In this paper, the results of modeling and interpretation of geophysical data acquired along two survey lines DD1 and DD2 have been presented. The geophysical data include IP-Res measurements at 460 points along these two survey lines using dipole-dipole array with the electrode intervals of 20 meters that have been conducted by Omid Geological Engineering and Geo-Science Company. Methodology and Approaches The raw field geophysical data along the two survey lines DD1 and DD2 have been modeled using two-dimensional (2D) smooth Inversion by RES2DINV and ZONDRES2D software packages. The 2D model sections are displayed in threedimensional (3D) form using RockWorks software. The inverse modeling results and geological studies lead to the recognition of the copper mineralization zones and local faults in Sharifabad area. Results and Conclusions The results of geophysics studies in Sharifabad area show high resistivity and IP values in two depth levels 0 to 25 m and 32-49 m. On the basis of the geological and geophysical studies, eight locations for drilling exploration boreholes are proposed, and as a result, three boreholes have been drilled up to a depth ranging 33-40 m. Drilling studies confirm copper mineralization with high copper values in the depth of about 39m. These studies have also led to the identification of four local faults near the mineralization zones.

This paper is devoted to application of integrated geophysical methods in the investigation of Nazloo dam site, located in 27 km NW of Orumieh city. In this study, a combination of shallow seismic refraction profiling and resistivity sounding and dipole-dipole profiling methods were applied. The goals of study were the determination of alluvium properties such as thickness and grain-size, preparation of iso-depth map of the bed rock, iso-thickness map of alluvium in the dam foundation and rock mass quality in the dam embankments. The results lead to identify three layers in the alluvium with resistivity of 100, 300, and 1000 W m and P-wave velocities of 2000, 1000, and 500 m/sec from depth to surface respectively. Maximum thickness of the alluvium was found to be about 70 meter below the dam axis.

dipole asymmetry is among the most important anomalies in the cosmic microwave background (CMB). A dipole, if primordial, would challenge the isotropy of the Universe. In this work, we propose a novel method to find the direction of the dipole and its amplitude and assess its significance. The method is based on the comparison of annular variances on the sphere. We find the direction on the sphere around which the difference of the annular variances on the two hemispheres is maximized. By applying this algorithm on symmetric CMB simulations we get the distribution of the measured dipole amplitude for these null cases, providing us with the baseline for quantifying the significance of dipole amplitude of any other CMB maps. In particular, we find the statistical significance of the observed Planck dipole to be 1. 6σ . Our simulations show that although the proposed method is not more powerful in detecting the dipole compared to other algorithms, its relatively low computational cost (performed in the pixel-space) is its advantage. This paves the way for a straightforward upgrade of the method which uses spherical caps instead of rings and thus, by increasing the number of pixels used in calculating the variance, improves the results significantly.

Geoelectrical surveys were carried out in Khenadareh-bala area, Sarband district, Markazi province, Iran for exploration of the graphite veins. In Sarband region, there are some potential areas for graphite mineralization, but most of them are not economical. Geoelectrical surveys were designed in Khenadarehbala area based on the geological evidences and physical properties of graphite. At first, self-potential (SP) method was carried out along 10 N-S profiles with 2 m distance between measuring points. Then, mise-a-la-masse measurements were implemented over there. The prepared self-potential and equipotential maps confirm each other and prove the presence of graphite mineralization with north-northeast trend. After that, resistively measurements were performed over the same profiles using dipole-dipole array (AB=MN=4 m) for more investigation of graphite distribution in the depth. The apparent resistivity pseudo sections indicate that the graphite veins (p<20 Wm) are approximately extended to depth of 25 m where SP profile shows the amplitude about -200 mV. Some excavation such as exploratory pits, well, and trench dug in this surveying area, demonstrate that these veins are discontinuous, thin, and impure.

Summary The host rock in Chumalu area includes the Eocene volcanic rocks and the Oligocene monzonite intrusive mass that have undergone propylitic-carbonate, silica, and silica-argillic hydrothermal alterations. The hydrothermal activities resulting from the injection of intrusive mass have produced two types of mineralization in the region: the first mineralization type is a silica-shear zone having N70E trend, and the second type is in the form of a bunch of veins with an approximate trend of northwest to southeast, located in the north of the first mineralization type. The mineralization is of the form of vein, veinlet, massive, scattered and replaced, and follows the trend of the faults. The ore contains lead, zinc and fluorine, along with copper, gold and silver, which are formed of chalcopyrite, pyrite, galena, sphalerite, cerussite, calcite and fluorite minerals. Based on the results of the geological studies conducted in this study, the mineralization characteristics of Chumalu area are of the type of lead and zinc hydrothermal deposits. Induced polarization (IP) and resistivity data acquisition were first designed and carried out using rectangular array to determine the anomalous zones, and then, using dipole-dipole array to determine the lateral and depth limits of these anomalies. Then, modeling of IP and resistivity data was done using smooth inversion method. For better representation of the results, all two-dimensional (2D) sections were combined and as a result, a three-dimensional (3D) model was presented. Consequently, an anomaly with an approximate east-west orientation in the south of the area has been extended on the silica-shear zone, and some anomalies with an approximate north-south orientation in the north of the area, in relation to the fractures of the basaltic deposits, which can be linked with metallic mineralization in the area. Anomalous areas with high chargeability and medium to low resistivity values have been determined. High chargeability values for some anomalies in the north of the area are probably due to the presence of scattered pyrites in depth. Finally, 6 points were proposed for drilling. Introduction Application of IP and resistivity geophysical methods and their integration with geological studies is of great importance in the exploration of sulfide metal deposits. The Chumalu area is located 70 km northwest of Zanjan in the Tarom-Hashtjin metallogenic zone, which has possible potential for metal reserves and mineral resources. The purpose of this research is to collect and process raw IP and resistivity data using the smooth inverse modeling, interpretation of the results based on geological studies and finally determining the anomalous limits, depth and thickness of probable mineral masses in the area and at the end, suitable locations for drilling are suggested. Methodology and Approaches This research is based on field and laboratory studies. In order to conduct geological studies, alteration, mineralization and determination of the genesis of the mineralization, 8 thin sections and 9 polished sections of surface and subsurface samples from the mineralization ore and host rock were prepared and studied. Moreover, field operations of IP and resistivity data acquisition were first made in the form of 4 networks using rectangular array in order to determine the anomalous limits with a current line of 800 meters long, electrode spacing of 20 meters, and the distance between the lines 50 meters. Then, 6 lines using dipole-dipole array were surveyed in order to explore the lateral and depth limits of these anomalies with electrode spacing of 20 meters. Then, modeling of IP and resistivity data was made by 2D smooth inversion method using RES2DINV and ZondRes2D software packages. Furthermore, all 2D sections were combined using RockWorks software and a 3D model was presented. Ultimately, possible mineralization limits were identified and suitable sites for drilling were proposed. Results and Conclusions Based on the geological studies, lead and zinc mineralization in olivine basalt volcanic host rock and part of the monzonitic intrusive mass in Chumalu area occurs during hydrothermal processes and in the form of veins along fault structures. Chumalu mineralization is of hydrothermal lead and zinc type. Based on geophysical and geological studies, anomalies have been introduced that have high chargeability and medium to low resistivity, as probable mineralization. Finally, 6 locations were proposed for drilling.