Prediction of air pollution of Ahwaz City by improving energy efficiency

Since the development of industries, vehicles and the people in the cities and their suburban areas, carbon monoxide, sulfur dioxide, nitrogen dioxide and some other pollutants have been increasing. This study has been conducted to predict the air pollution, utilizing model of atmospheric pollutant dispersion for a large city of Ahwaz, with regard to land use, the amount of pollutants released from point, area and line sources, subsequently integrated mesoscale model was used to predict the dispersion and concentration of the air pollutants. The main purpose of the study was to determine the dispersion factors and the meteorological condition which cause the air to be polluted over the study area. To achieve the main goal of the study, establishment of the emission inventory, meteorological simulation and (CO), (NO, NO2) and SO2 dispersions sources in the Ahwaz city regions by using the WRF CAMx and evaluation of the model performance were done. The mean difference between prediction and observed data was obtained by Root Mean Square Error (RMSE) and the Peak results are as follow: SO2, 75 ppb, NO2, 100 ppb, NO, 85 ppb and CO, 40 ppb. A comparison of the observed peaks from the air pollution measurement stations at ground level, and the results of WRF / CAMx model show the error of the peaks is less than 30%, which this percentage indicates that input data to the model and to the real data are close to each other. Normalized error was ±20% and normalized bias was between -15% to +15%, this amount for the air pollution models are acceptable. Also, the BIAS ERROR calculates the relationship coefficient between the simulated prediction and actual data. The results showed that the Zergan Power Plant has more effect over the North East part of the Ahwaz city than the Ramin Power Plant, due to distances and the wind direction characteristics and that the pollutants concentration is equally related to emitted pollutants from their own sources. The Ahwaz city line sources have the most effect on the central city, concerning the four pollutants. It can be concluded that the concentration of SO2 and NO2are higher than the NAAQS (National Ambient Air Quality Standards) value for SO2 (75 ppb) and NO2 (100 ppb) and other pollutants level are within the limit

Effect of post-deformation annealing on the microstructure and mechanical behavior of an Fe-Ni-Mn steel processed by high-pressure torsion

Research was conducted to investigate the effects of high-pressure torsion (HPT) and post-deformation annealing (PDA) on the microstructure evolution and mechanical behavior of an Fe-9.6Ni-7.1Mn (at.%) steel with an initial lath martensitic microstructure. The experimental results showed that HPT processing led to the formation of an ultrafine grain martensitic microstructure accompanied by small amounts of strain-induced austenite. Phase analysis and microstructural examination confirmed that during PDA at 600 °C a large fraction of fine and coaxial austenite grains was introduced in the microstructure by diffusionless shear mechanism whereas its volume fraction at ambient temperature was drastically decreased by increasing the annealing time. Also, the grain size was reduced from a value of about 5.2 µm in the solution-treated specimen to ultrafine values of about 570 and 280 nm for the martensite and austenitic phases, respectively, after PDA for 7.2 ks. PDA yielded an outstandingly good combination of an ultimate tensile strength (1340 MPa) and fracture strain (11.9%) in comparison to the solution-annealed condition which can be attributed to the finer grain size and the presence of shear-formed austenite in the microstructure. In addition, the fracture mode changed from a fully ductile nature in the solution-treated specimen to a combination of ductile and brittle nature after applying the HPT and then returned again to a ductile behavior after PDA

Effect of high-pressure torsion on the microstructural evolution and mechanical properties of an Fe-10Ni-7Mn (wt. %) lath martensitic steel

The high-pressure torsion (HPT) process is a severe plastic deformation (SPD) technique which imposes exceptionally high strains to produce extremely small grain sizes in bulk materials. In this paper, the HPT process was carried out on an Fe-10Ni-7Mn (wt.%) martensitic steel up to 20 revolutions at a rotation speed of 1 rpm under a pressure of 6.0 GPa at room temperature. The effects of the HPT process on the microstructure evolution and mechanical properties of the alloy were investigated by X-ray diffraction (XRD) analysis, electron backscatter diffraction (EBSD), micro-hardness measurement and conventional tensile testing. The XRD analysis revealed no changes in the detected phases after deformation. A significant refinement in grain size from 200 m in the initial microstructure to around 230 nm after HPT was observed by EBSD. Although based on a rigid body assumption the imposed strain is linearly proportional to the distance from the center in HPT-processed disks, after 20 revolutions a uniform micro-hardness increment up to ~650 Hv was achieved. Moreover, the tensile strength of the alloy increased from ~800 MPa in the solution annealed condition to about 2300 MPa after the HPT process with a total tensile strain of 4%. Experimental results indicated that the HPT process leads to improvement of the tensile strength with a reasonable ductility due to the significant refinement of the microstructure