نشریه علوم و فنون سازندگی
سال سوم شماره 3 (پیاپی 9، پاییز 1401)

Today, remote sensing is one of the most important stages of exploration using satellite imagery to detect minerals. In this regard, it is important to study and recognize different and new methods because of increasing the probability of exploration and reducing the risk. Methods that, while simple and efficient, also reduce exploration costs. For remote sensing studies in the study area, after preparing the required information such as satellite images (images of Aster and Landsat 8 (OLI) satellites) and 1:100000 Siahhroud geological map, a database containing all the required information was formed. In order to use satellite images in exploratory studies, first the necessary preprocessors appropriate to the type of satellite used were implemented on the images. These predictions include Crosstalk Correction, Radiometric Correction, Atmospheric Correction, Geometric Correction, and Elimination of Vegetation Effect by the Vegetation Index (NDVI). Then, for separation and detection of mineralization control evidences including lithological type, geological structures, alterations (including argillic, phyllic, propylitic, silica and iron oxides) and lines from image processing methods such as band ratio (BR), false color combination (FCC), Selective principal component analysis (SPCA), Mixture Tuned Matched Filtering (MTMF), Directional and frequency filter (FFT) were used. Finally, the final maps of the alterations as well as the maps of the geological structures were prepared and the important areas affected by the alterations were identified.

In this study, in order to prevent corrosion and wear damage in the metal equipment of Esfordi Phosphate Processing Plant, appropriate solutions to reduce the corrosion and wear rate have been presented and evaluated. Vapor phase corrosion inhibitors (VCIs) have been used to prevent corrosion in the bottom of storage tanks and liquid phase inhibitors have been used to prevent internal corrosion in pipelines. NACE TM0208 standard was used to evaluate the VCI inhibitor and potentiodynamic polarization (PDP) and electrochemical impedance test (EIS) were used to evaluate the liquid phase inhibitor. The results of PDP and EIS tests showed a reduction of corrosion rate up to 93%. However, the results of the VCI inhibitor evaluation showed that the corrosion rate in the presence of the VCI inhibitor was completely stopped. To prevent wear of the samples, the IN625 superalloy coating was applied to a plain carbon steel substrate used at the Esfordi plant. To investigate the wear behavior of the applied coating, the pin wear test on the disk was used. The results of the pin pin test showed that if the coating is applied, the coefficient of friction of the samples decreases from 0.7 to 0.1, which leads to a special improvement in the wear of the samples. Hardness test was used to evaluate the mechanical properties of the applied coating. The results of hardness test showed that the hardness of the samples increased from 100 Vickers to 340 Vickers by applying the coating.

Sour gas is very foul-smelling and toxic to breathe due to its sulfur content, and if it is mixed with water, it will be very corrosive and cause serious damage to equipment and the environment. For this purpose, sweetening methods will be used to maintain safety issues and adjust the standard composition of products. The most common chemical absorption processes are sweetening with amines. In this research, which was conducted for the 22nd and 23rd phases of South Pars, the solvent methyldiethanolamine was used to separate the hydrogen sulfide in the flare gas and make it burnable. For this purpose, acidic compounds are first separated from the incoming sour gas in an absorption operation at low pressure and high temperature. In the process of absorbing sour gas with amine solution, amines in combination with acid gases produce salt complexes, and then they are broken in a high temperature and low-pressure disposal operation, and the amine is regenerated in a distillation process. The results showed that this method will have a suitable ability to separate the contents of hydrogen sulfide from flare gas and the amount of hydrogen sulfide in the gas stream will reach 7.3 kmol/hour from 310 kmol/h.

Wastewater collection networks are a part of urban infrastructure and their repair and maintenance impose lots of costs on society. In evaluating the methods of reconstruction and renovation of sewage collection networks, only direct costs are generally considered and social and environmental costs are not considered. In this research, to evaluate the sewer reconstruction methods and to choose the appropriate method, four main criteria were chosen for decision-making according to the environmental conditions of the project. Social and environmental criteria, in addition to conventional technical and economic criteria, have been used in decision-making. Based on the decision criteria and proposed reconstruction methods, questionnaires were applied to use the AHP method for decision-making. The results showed that the technical criterion is preferable to other criteria, and the OmegaLiner and CIPP methods have a higher priority in the application. In the case of Ahvaz city, the main problem is the lack of resilience of the urban sewage collection network against rainwater infiltration. Furthermore, the high level of underground water with the trench instability has caused the application of open-trench methods to encounter many other social problems in addition to technical problems. Unfortunately, most of the sewage network in Ahvaz is worn out and the main sewage collection lines are under construction. In general, it is recommended to use trenchless methods to build the sewage collection network in Ahvaz city. OmegaLiner and CIPP methods are preferred among reconstruction methods.

This study aimed to provide an applied framework based on Mesh Less and Differential Evolution Adaptive Metropolis (DREAM) algorithm to accomplish the simulation-optimization procedure of water inflow into the tunnel. Also, another purpose was to compare numerical and analytical methods in calculating the water inflow in the Kerman water conveyance tunnel. A simulation-optimization structure was introduced in order to find the optimum hydraulic conductivity. In this plan, the Mesh Less predicted the groundwater level, and the DREAM uncertainty analysis algorithm determined the optimal values of the hydraulic conductivity. The modeling of groundwater level and water inflow was then executed for the steady and unsteady states, and the results were compared with the measured values. The RMSE for comparing the simulated and measured groundwater levels was obtained at 2.573 and 3.481 meters, respectively, for steady and unsteady states. The findings of this study confirmed that the hydrothermal conditions specifically affected the permeability. Also, the NSE value for the north and south tunnels was determined as 0.83 and 0.87, respectively. Finally, it was found that the outcomes of the analytical methods are much lower than the numerical method.

Bridges are important components of the road networks and are classified as high importance from the structural safety standpoint. Therefore, maintaining their stability and improving their performance are important. The issue becomes more important considering that most of the existing bridges in the national transportation system are old, which can lead to their failure when subjected to dynamic loads caused by earthquakes or other sources. One of the conventional methods for health monitoring of structures and detecting the damage state is structural signal processing in the time-frequency domain using wavelet transformation. Previous studies proved the efficiency of this method. In this study, to benefit from the capabilities of this approach, one of the Jinnah grade-separation bridges in Tehran with a segmental deck under different damage scenarios has been studied. For this purpose, the difference in the displacement response between the intact and damaged bridge deck under the effect of the considered load is used as the input signal of wavelet transformation. The results show that the proposed method can accurately identify the damage location using one-time sampling and a minimum number of sensors.