نشریه مهندسی عمران و محیط زیست دانشگاه تبریز
سال چهل و نهم شماره 3 (پیاپی 96، پاییز 1398)

Exposure, takes place every day from natural and artificial sources, but the highest dose is related to normal radiation, which most of it is related to radon exposure. According to the World Health Organization reports, radon after smoking is considered as the second leading cause of lung cancer in the community (Salgado, 2015) (Wheeler, 2012). Ramsar is known as the riskiest place in the world in natural gas radon exposure. Given that, many people in their life or work, such as researchers, miners, hospitals, government offices, schools are exposed to the radioactive material, the feasibility of using available and affordable materials as an adsorbent of radon gas can play an important role in increasing public health (Yousefi, 2014). The objective aim of this study is investigating of various factors affecting radon reduction with montmorillonite in areas with high natural radiation. Effects of weight, adsorbent particle size, humidity, comparison of different materials to reduce radon were considered as other aims of this research.

For economic reasons, current design philosophy allows buildings to experience inelastic deformations under the influence of strong earthquake ground motions. As a result, the design lateral strengths prescribed in earthquake-resistant design provisions are generally lower and, in some cases, much lower than the lateral strength required to maintain a structure in the elastic range in the event of severe earthquakes. Reductions in forces, produced by the hysteretic energy dissipation capacity of a structure, are expressed by strength reduction factors. The yield strength-reduction factor,  is defined as the ratio of the elastic strength demand to the inelastic strength demand as follows.

Air pollution caused by mobile sources is one of the most important problems in the most populated cities of the world and Iran. But most developing countries are not able to accurately identify and determine the composition and amount of the emission from vehicles and evaluation of them, which restricts local policymakers to adopt appropriate policies and decisions. Mobile sources of Tabriz, Iran with about 0.5 million number and the predicted share of about 72% of air pollution (Kahforooshan and Fatehifar, 2013), are the most important source of air pollution in the city, although no studies have been done in this area. In this study, the IVE emission model was used to calculate the amount of emissions from passenger cars, taxis and buses, and the AERMOD model was used to investigate the dispersion manner of CO, NOx, SOx, and PM2.5 pollutants and compare the predicted results by the model and measured values at air quality monitoring station sites.

Accidents as a threat factor to the transport system have widespread political, social, and economic dimensions, which is increasing in developing countries. Iran, as a developing country, has not escaped this danger, but in recent years it has taken preventive measures and crash statistics has been decreasing. Crash injury severity is one of the most important criterions of measuring the costs of accidents. Different methods have been used for predict modeling. Support Vector Machine is a relatively new modeling technique which was proposed to solve the classification and regression problems. That shows accurate and acceptable performance. In the present study, it has been tried to model the severity of accidents with a combination clustering and classification approach, with the help of neural network algorithms, simple parsing, SVM, KNN, and C4.5 algorithms and by comparing the algorithms used assess the ability of each of the algorithms in the prediction of the severity of accidents. The purpose of this study is to evaluate the performance of support vector machine algorithm to predict the severity of road accidents and identify the factors that affect the severity of accidents.

One of the powerful methods in tunneling design in rock mechanics and geotechnical engineering is analytical method. Among the analytical models the best model is the use of complex potential functions one. The complex potential method applies conformal mapping. Applications of conformal mappings are made to two-dimensional boundary value problems involving rock mechanic, soil mechanic, heat flow, electrostatics and ideal fluids. Of particular interest is the ability of conformal mappings to map regions with a complicated boundary shape onto regions with a simple boundary shape McMahan (2008). This is because such mapping can be used to solve two-dimensional boundary value problems for the elasticity equations in regions of complicated shape. The required solution follows directly from the fact that conformal mappings map one analytic function into another one.

The analysis of plates on elastic foundation has a wide range of applications in various fields of engineering, such as civil, mechanical, aerospace, nuclear and marine engineering. Due to soil behavior is dependent on numerous factors, providing full and comprehensive model for foundation is very complicated. Therefore, in order to express properties of the substrate are used the simpler models based on the elastic properties. The simplest of those models, which was presented by winkler in 1867, assumes that the soil medium containing a system of independent spring (Liew et al, 1996). To increase the accuracy of modeling two-parameter models arose that the effect of shear stresses in the substrate is also included. In these models a new parameter is proposed to establish a mechanical connection between the independent springs. An approximate solution for the bending of moderately thick rectangular plates using numerical differential quadrature method was proposed by Han and Liew (1997). Teo and Liew (2002), presented a solution for analysis of shear deformable rectangular plates on Pasternak foundations by using differential cubature method. Displacement potential functions (DPF) method is one of the effective and efficient techniques that can be used to solve elasticity problems. The most advantage of DPF method is that the system of differential equations is uncoupled or at least simplified. This method has been used for 3D analysis of plates by a number of researchers such as Nematzadeh et al (2010) and Moslemi et al (2016) for the bending and buckling solution, respectively.

In the present paper, an explicit algorithm is developed for calculating buckling load of frames. Here, the modified Dynamic Relaxation method is utilized so that the first structural buckling load is achieved.

The present paper investigates the operation of the sliding mode on three-dimensional benchmark building with smart base isolation to reducing the dynamic responses of seismically excitation. According to the being three-dimensional, interweaving responses of the structure with each other, cohesiveness of behavior of superstructure and base level and computing the nonlinear force of base isolation systems, this building is very complex. Under these circumstances, we used extended sliding mode theory to applying the benchmark building. Also, the actuators are located only at the base level and in the two main directions. The results indicate that the proposed control system improved the building responses.

This work presents a numerical investigation of free surface overflow from a sharp-crested weir based on 2-D weakly-compressible Smoothed Particle Hydrodynamics (SPH) method. The flow field behaves highly dynamic with strongly deforming free surfaces generated by overtopping jet. A different way of initializing the computation is developed with the relative merits of more rapid convergence to desired steady state. Improved preservation of bulk fluid volume is obtained by recourse to a new hydrostatic correction term, substituted into the mass conservation law. This is confirmed by analyzing the hydrostatic tank test separately in absence and in presence of the correction term. Improvement is also achieved in predicting the draining process of weir-reservoir system when there is no inflow. Comparison with experimental nappe envelops as well as velocity and pressure distributions demonstrate satisfactory agreement in each case.

Natural soft clay soils due to the lack of sufficient bearing capacity and the high deformation potential require to be improved using either chemical stabilization methods or physical methods such as soil reinforcement or pre- compression. The method used is greatly influenced by technical and the economic considerations as well as the physical characteristics required (Abdi and Zandieh, 2014). Chemical stabilization generally results in increasing the strength and the bearing capacity and reduces the swelling- shrinkage potential of the clayey soil. On the other hand from ancient times humans have used natural fibers to alleviate the weakness of soil in resisting tensile stresses (Abu-Farsakh et al., 2008). Now-a-days due to the technical progress made synthetic materials such as geo-synthetics are used for soil improvement. Use of geo-synthetics such as geogrids and geotextiles have grown rapidly in the construction of soil structures such as embankment dams for reducing the volume of materials needed as well as drainage purposes, increasing bearing capacity in foundation engineering, etc (Alawaji, 2001). These materials are easy to use and environmentally friendly. Coarse grained materials are also employed in construction of reinforced soil structures due to high drainage and shear strength characteristics as well as volume stability due to moisture variations and time (Alawaji, 2001).