Year:2023 | Volume:53 | Issue:3|Papers Count:19

Pipeline network is one of the major agents of the economic growth and development of a country, which is used to transport fluid fuels, wastewaters, and any other fluids. When these pipelines meet seas and oceans, pipes are laid on the solid bed and it causes changes in the flow pattern around the pipes. In result of these changes, the shear stress of the bed under pipelines and turbulence of current will be increased, and scour will occur under pipelines and the scour hole will form and develop. These holes cause damage and failure to the pipe due to the pipe weight and oscillating loads. Therefore, it is very important to study the scour depth and effective variables to reduce scour and prevent damage. Researchers have conducted experimental and numerical studies on scour phenomenon, considering various types of flows and conditions, and have provided different relations over the years.In this research, the effect of various factors on this phenomenon in waves is investigated using Gaussian process regression (GPR) and support vector machine (SVM). To this end, several laboratory data were used and after defining several non-dimensional parameters the performance of these methods was evaluated. The result of this research demonstrated that these methods are better than experimental relations and have promising outcomes. This study has shown that an SVM model with KC, Re and  variables in wave-induced current has the best results. It is worth mentioning that the KC variable has the most significant effect on the scour below pipelines.

Waste stabilization pond (WSP) is a conventional and widely applicable wastewater treatment unit globally. This system does not require complicated mechanical operating systems but it should not be classified as a simple process at all. Facultative ponds (FP) are the heart of this system as they use the natural symbiosis of facultative bacteria and algae for organic removal. The performance of FP is very reliant on different parameters such as wastewater influent characteristics or environmental operating conditions. Nonetheless, they are simply designed and operated based on parameters like surface organic loads and hydraulic retention time (Khosravi et al. 2013). Some literatures have recently focused on the optimization of WSP layout for higher performance (Shahsavani et al. 2019; Decostere et al. 2017; Espinosa et al. 2017). For example, a question is that which form of FPs, in series or parallel, have the highest performance or operational reliability? Answering to this question is practically a challenge. There is little chance in full scale to compare the performance of FPs with the layouts in series and parallel for long term, with same source of real wastewater, similar climate and operating conditions. This research primarily evaluates and compares the performance of FPs (2008-2020) in series and parallel layout in Delijan WSP.

Today, the population of most countries is growing exponentially. Countries whose main economic dependence is on oil production. This issue, along with the lack of a rational management system for increasing fuel consumption, groundwater resources and it has seriously threatened the environment in industrial hubs (Ghaderi et al., 2019). Of the various compounds of water pollutants that enter water sources mainly through raw wastewater and its effluents, phenolic compounds are of special importance and can even enter water sources naturally (Ghaderi et al., 2019; Ghaderi et al., 2020). Nitrophenol, a member of the phenolic family of pollutants, is a carcinogen and is known for its many adverse effects on humans and aquatic animals. In recent decades, chemical reduction of nitro phenolic compounds has been widely reported as an advanced removal method for such hazardous dyes from reservoirs (Din et al., 2020). Nitrophenols, which are toxic, inhibitory, and biodegradable organic compounds, are widely used in the chemical industry to make pesticides, dyes, and drugs, and are often found in the effluents of industrial wastewater treatment plants. (Ma et al., 2000).

Historically for geotechnical engineers, the design and construction of structures on soft soil sediments has been a challenge. The ability to serve and limit the conditions as well as the cost and time program is considered. To meet these requirements, many types of construction methods are available. For example, replacing soft soil with other materials, reinforcing embankment, using lightweight filling materials, prefabricated vertical drainage and overhead or suction to accelerate consolidation, stage density, use of stone columns or different options from cement and cement mixture The soil is like a deep mixing or candle with reinforced reinforcement. Among all existing construction methods, the use of stone columns in soft soil is one of the most common things to reduce session and improve stability and freight capacity. However, when the stone columns are installed in very soft soils, it results in excessive clay pouring into the inner parts of the stone columns and reduces its stone column bearing capacity as well as its drainage capacity (Almeida, 2019). The stone column obstruction has been widely reported and its obstruction on the amount of soft soil improved with the stone columns is visible (Tai and Zhou, 2019) The use of stone columns is a popular technique in improving land with fine soil that can easily Reduce drainage and time of consolidation, as well as increased hardness and shear resistance (Indraratna, 2017). Vertical drainage, such as prefabricated drainage, sand drainage, stone columns and pebbles that are commonly used to accelerate or increase soil resistance. Many previous studies have reported that the area of the impact and resistance of the well causes excess water pressure in the soft soil to be improved with drainage (Nguyen, 2020). The stone column contains empty space or pores. The microphones are attached to the surface of the pores, through which penetrating water flows. Studies show that hydrodynamic or colloidal force is generally responsible for separating the microphones from the pores (Survi and Kousik, 2018). Stone columns create drainage paths due to high permeability (Weber et al., 2010).

Using renewable energy sources instead of fossil fuels is a fundamental way to reduce environmental pollution caused by greenhouse gases. Geothermal energy is available all over the world and has an important role in the supply of renewable energy. In order to collect geothermal energy various heat exchanger systems have been developed in recent years that thermal activated piles (energy piles) are one most of them. Reinforced concrete piles have been widely used as a geothermal heat exchanger to access the relatively constant temperature of the ground for efficient heating and cooling of buildings. Energy piles are heat capacity systems that have been increasingly exploited to provide both supplies of energy and structural support to civil structures (Batini et al., 2015). Concrete has a good thermal conductivity and thermal storage capacity, which makes it an ideal medium as an energy absorber (heat exchanger). To use these properties for energy foundations, high-density polyethylene plastic pipes have to be installed within the concrete. The plastic piping can be fixed to the reinforcement cages of the energy foundation in a plant or on the site (Fig. 1).

In the present paper, the improved sliding mode control algorithm are presented. This strategy is based on the combination of sliding mode control and Bang-Bang control theory. The Bang-Bang theory can switch abruptly between the on and off situation, this property can improve the performance of sliding mode control strategy. Also, three thresholds used to decrease the time of using the control system and optimizing the responses of structure.

Graphics statics is a geometric method for analyzing and calculating the internal forces of structural members under external loads. In this method, two diagrams of structural form and internal forces in the members are determined and drawn graphically. The process of parameterization of this method in both form production and internal force calculations can lead to various designs with the least amount of time. In such circumstances, Architects and Civil engineers can make the best choice based on the criteria and objectives of the structure, form and geometric topology. In this paper, the parametric graphics statics analysis of various truss designs, derived from the popular species Warren, Pratt, Howe, and Fink, or any related free-form, is performed in the Python programming language in the grasshopper Plugin. The results of the analysis performed with the results in the available sources show that the proposed parametric graphics statics method has a high performance in calculating the internal forces of members of conventional trusses or free-form with any desired load.

Water quality monitoring through remote sensing involves establishing a reliable relationship between light reflectance (at specific wavelengths of bands) and water parameters collected in situ (Barrett et al, 2016). Estuaries can play an important role in changing the water quality of lakes, and according to studies, satellite images with high spatial resolution (better than 30m) have been used to study water quality. So, in Chalous River estuary has been selected due to its environmental importance in this research, and its qualitative parameters of salinity, temperature and pH have been studied. Also, to achieve these goals Sentinel2 and Landsat8 satellite images are used and the efficiency of these two satellites to determine the relationship between different physical and chemical parameters of water quality evaluated by comparing with the field measurements. Since Sentinel2 multispectral images comprise more bands compared to older multispectral images such as Landsat8, it is worthwhile to evaluate the possibility of evaluating water quality parameters using Sentinel2 multispectral data. In addition, the main mission of Sentinel2 satellite is continuous environmental monitoring, which if the significant relationship between satellite data and seawater quality parameters is proven, many concerns about environmental monitoring will be resolved and the lack of updated imagery data for monitoring changes in seawater quality will be addressed.

Heavy metal contaminants are the most important and most hazardous type of pollution that needs to be studied both environmentally and geotechnically. There are different concentrations of heavy metals in the soils (Zhang et al, 2019). Engineering properties of contaminated soil tend to significantly change due to chemical reactions between the soil mineral particles and the contaminants (Arasan and Yetimoglu 2008). Chu et al. estimated the shear strength parameters of contaminated soil by lead, zinc and cadmium. The direct shear experiment was performed and results indicated that increase of heavy metal concentration increases shear strength and cohesion. Also, the electrical resistivity of soils decreased with the increase in concentration (Chu et al, 2016). Based on the spreading of the heavy metals such as Lead and Zinc in the most parts of China, Li et at. conducted research on lead contaminated soil in these areas. Samples were made in OMC and MDD and cured for 2 days. Obtained results showed that the increase of the concentration decreased the thickness of diffuse double layer (DDL) and particles were in a flocculated micro structure form. Increasing the flocculation, increased the permeability coefficient of samples (Li et al., 2015). In this study, the effects of zeolites and rice husk ash were investigated. It should be noted that the soil mixture was sand with 20% kaolinite and also sand with 20% bentonite. After determining the performance of these two types of clay minerals in contaminated and uncontaminated conditions, 10% of the fine-grained fraction were reduced and the equivalent of 10% of zeolite or rice husk adsorbents were added.

For the first time in January 1991, the issue of studies and construction of urban trains was proposed by the esteemed representatives of the city of Tabriz in the Islamic Consultative Assembly. Due to the increasing growth of intercity travel in Tabriz and the need to use a 2-rail transportation system in order to reduce traffic problems, studies of Tabriz city train lines were conducted and Tabriz city train network including 4 routes, a total of 60km and 63 stations were designed.     The analysis of underground structures is very complex due to the interaction with the surrounding environment in a dynamic state. For this reason, less research has been done. One of the first people who investigated the effect of earthquakes on underground structures is Newmark, in 1968 he presented an easy method to calculate the relative strains of underground pipe structures and long tunnels (Bozorgnia et al., 1995). In 1969, Kuesel established a simple method for calculating earthquake forces on linear tunnels, which in most cases is the basic of later works. Douglas and Warshaw in 1971 presented the results of tunnel design analysis under the influence of earthquakes. Lee and Trifunac in 1979 investigated the response of the lined tunnel under the shear wave effect. In 1981, Owen and Scholl's studied three types of deformations, including compressive-tensile, longitudinal bending, and rhomboidal and elliptical deformations as the result of seismic vibrations in underground structures.

In controlling water resources, sluice gates have received attention from researchers due to the ease of installation and simplicity of the operation and the governing equations. The experimental study of (Henry, 1950) is one of the first research publications in this field that estimated the flow discharge coefficient for the sluice gate with a diagram. The studies of (Alhamid, 1999), Rajaratnam and Subramanian (1967), Ferro (2000), Daneshfaraz et al. (2016) and Heidari et al. (2020) are other studies in the field of hydraulics of sluice gate, that explains the importance of research in this field. In the present paper, results of experimental investigations on the effect of applying sill on discharge coefficient in different positions of the sluice gate are presented. The effect of sills including semi-cylindrical, cylindrical, pyramidal and rectangular cube in different widths was investigated.

Coarse-grained gravel (rockfill material) has numerous applications in engineering including filtration, gabion construction, channel lining, stilling basins, ponds, and cobble stone dams as well as flood control. In the fine-grained media, there is a laminar flow with a linear relation between hydraulic gradient and flow velocity so that the flow follows Darcy law (Eq. 1) (McWhorter and Sunada, 1977). However, in the coarse-grained media, due to the presence of voids, flow velocity is high with a tendency to the turbulent flow formation (Hansen et al. 1995), and there is a nonlinear relation between hydraulic gradient and flow velocity and flow follows non-Darcy law. Hydraulic gradient equations in the non-Darcy media considering steady flow condition are classified into two groups of power and binomial equations, according to Eqs. 2 and 3 (Forchheimer, 1901; Leps, 1973; Stephenson, 1979).

Considering the simple mechanism and low cost of bicycles and its advantages in the transportation industry, the present study intends to analyze the problems, obstacles and the importance of the existence of shared bicycles in the present and future from the perspective of Tehran citizens. Unlike most previous studies that have focused on a specific component of the demand debate, this study analyzes its problems and barriers with a more general view of the importance of shared bicycles.

Transaction costs constitute an essential part of the costs of a construction project (Rajeh et al., 2015). One of the critical factors influencing the choice of project delivery method is the transaction cost (Whittington, 2008). Transaction cost economics has meaningful solutions to reduce transaction costs. So far, it seems that no research has examined how to choose a project delivery method based on transaction cost economics criteria. Transaction cost economics examines the governance structure of institutions based on the three dimensions of specificity, uncertainty, and frequency of transactions (Williamson, 1985). This paper examines how to select the delivery method in construction projects, using the transaction cost economics approach to determine the governance structure. Three methods of traditional (design-bid-build), design-build and construction management are investigated.

In this study, we attempt to have numerical and software analysis of behavior, deformation and strain caused by local dental loads (dent) in GFRP tanks. The load-displacement and the load- Strain diagrams in experimental and software conditions have also been analyzed, compared and evaluated. The research can be used in oil company projects, water organization and different types of tanks which are exposed to local loads. the experimental and theoretical researches on GFRP tubes and tanks under dental loads and concluded that all samples have linear behavior from beginning to end and proceed with the same slope which is due to the behavior of the GFRP materials (Zarrin, 2018). To test the behavior of experimental specimen under the influence of Dent’s load, wedge is used. In another studies different types of dental loads are applied to the tanks like Dome-shaped dental load, Circular dental load and Rectangular dental load (Jajo, 2014). To understand the importance and necessity of research, we must first study the dental load, how it is applied to the tanks, the dangers of applying it to the tanks and the ways of resistance against these loads.

One of the important issues in the production of concrete is environmental variability that affects the concrete and elements constructed from this material. Due to the importance of different characteristics of concrete in short- and long-term conditions, this article aims to investigate the influence of initial temperature conditions of self-compacting concrete on its long-term characteristics and determine the initial optimal temperature of concrete. For these purposes, several experiments under three temperature conditions of 5, 20, and 40 degree-of-Celsius were conducted to evaluate the rheology and mechanical properties of fresh concrete in the range of 7 and 28 days. In these experiments, alternative mineral admixtures of cement such as micro-silica, fly ash, and zeolite were used to build the concrete specimens. Results demonstrate that the mechanical properties of the specimens increase with increasing initial temperature in the short term, while such properties significantly decrease in the long term compared to the specimens constructed under lower initial temperature. Moreover, the fluidity of self-compacting concrete increases with increasing initial temperature.

Brick is the most widely used construction material. Demolition of buildings and production of construction waste, including clay brick, are dramatically increasing in an alarming rate. The production of traditional bricks such as clay bricks has hazardous impacts on the environment, such as pollution and extensive use of natural resources. This study addressed the application of the geo-polymerization process as an environmental and sustainable method to produce new bricks from clay brick waste and different types of fillers. Accordingly, the powder and grains of clay brick waste, dune sand, washed sand, industrial sodium hydroxide, and water glass were utilized to prepare cubic and brick-shaped geopolymer samples with different mix designs and then cured at 70 °C. The samples' compressive strength, water absorption and SEM analysis were examined. According to the results, the highest compressive strength for cubic mortar samples was obtained in the case without filler; for these samples, with mass ratios of water glass to sodium hydroxide solution equal to 1 and 2, compressive strength was 18.45 and 22.15 MPa, respectively. In the brick samples, the highest compressive strength was obtained in the 28-day and 8 M geopolymer samples, which was equal to 25.38 MPa. On the other hand, the geopolymer samples made by sand filler had higher compressive strength and lower water absorption in comparison to other samples. Therefore, sustainable production of geopolymer bricks from clay brick waste and inexpensive materials as the filler can be a step toward mitigating the environmental impact of construction and demolition waste.

Soluble rocks such as gypsum and anhydrite are problematic rocks in geological engineering and geotechnics. The presence of these rocks in the construction of water structures such as bridge piers, coastal walls, diversion dams and dams, etc. due to their solubility and behavioral mechanism and deformability of gypsum-containing materials poses serious challenges in terms of stability The construction of Marash Dam, which is located about 98 km from Zanjan city, has special complications due to the presence of gypsum and anhydrite materials along with marl materials. Due to the fact that the materials of the dam bed, which contain gypsum and anhydrite materials, are exposed to loading and moisture, as well as solubility at the same time, so it is very important to study the mechanism of solubility and final strength of these rocks at different humidity. The effect of moisture on the deformation of gypsum materials is quite obvious and can sometimes lead to a decrease or increase in the strength of gypsum materials in certain conditions, Hooka et. al. (2006). At high pressures and in the presence of moisture, the dissolution rate as well as the compressive strength of gypsum and anhydrite samples have complex behaviors and depending on the contact area of the materials relative to each other and the moisture content, the dissolution rate can decrease and increase resistance over time, Hasan F, Ibrahim A, (2021). Based on the explanations provided and others' research, in the present study, according to the site conditions, rock samples from different depths (10 samples) to perform uniaxial tests and determine the Young's modulus and other parameters including natural density, moisture content and Poisson's ratio. And the porosity was transferred to the laboratory. In addition to resistance tests, solubility tests were performed to determine the maximum solubility of materials containing gypsum and anhydrite under different conditions (Marash dam water and distilled water and water containing 1% sodium chloride). By performing statistical and graphical analyzes, the behavioral status of gypsum rock samples in relation to various parameters has been investigated and its results have been presented.

Due to the disadvantages of some existing connections such as the lateral-torsional buckling of RBS connections (Akbari Hamed and Basim, 2020; Akbari Hamed and Bafandeh Nobari, 2021), Saeidzadeh et al. (2022) proposed a novel partial-strength and semi-rigid (Chenaghlou and Akbari Hamed, 2017; Eurocode3, 2005) self-centering connection which eliminates residual drifts and provides more ductility in comparison with existing connections. Considering the stable cycle behavior and the advantages of this connection, in this paper, the structural cyclic behavior of this novel connection was compared with existing connections under the applied quasi-static loading. To this aim, the verified finite element models of four connections including welded moment connection (WMC), post-tensioned strand connection (PTSC), friction damper connection (FDC) and metallic yielding damper connection (MYDC) were considered.