air pollution is one of the most important problems in urban areas that always threaten citizen's health. photochemical smog is one of the main factors of air pollution in large cities like tehran. usually smog is not only a part of nature, but is being analyzed as an independent matter, which highly affects on the nature. it has been used as relationship between atmospheric elements such as te...

At low redshifts, measurements of the total baryon content in stars, atomic and molecular hydrogen, and cluster gas fall a factor of two to four below the baryon density derived from observed light-element ratios and nucleosynthesis arguments. A possible hiding place for a significant fraction of the missing baryons is in the warm/hot gas at temperatures T= 10 − 10K. We present predictions of t...

Metal forming processes, compared with machining ones, reduce production steps and increase manufacturing speed in addition to saving raw material. In this paper, forming process of column of a steering mechanism is investigated by finite element analyses and experimental tests; and optimum die design parameters are found. Forming process parameters including die opening angle, bearing length, ...

Modeling the flow curves of materials at elevated temperatures is the first step in mathematical simulation of the hot deformation processes of them. In this work a comparative study was provided to examine the capability of three different constitutive equations in modeling the hot deformation flow curves of AZ91 magnesium alloy. For this, the Arrhenius equation with strain dependent constants...

more recently, titanium and aluminum alloys are gaining more interests to be implemented in hydro-forming applications. it is necessary to predict forming limits for these sheet alloys. forming limits play an important role in metal forming processes. forming limit diagrams, present the limit strains for various linear strain paths. in other hand, forming limit curve (flc), illustrates localize...

Metal forming processes, compared with machining ones, reduce production steps and increase manufacturing speed in addition to saving raw material. In this paper, forming process of column of a steering mechanism is investigated by finite element analyses and experimental tests; and optimum die design parameters are found. Forming process parameters including die opening angle, bearing length, ...

  Abstract   Recovery and recrystallization phenomena and effects of microalloying elements on these phenomena are of great importance in designing thermomechanical processes of microalloyed steels. Thus, understanding and modeling of microstructure evolution during hot deformation leads to optimize the processing conditions and to improve the product properties.   In this study, finite element...

We examine the properties of low-redshift circumgalactic medium (CGM) around star-forming and quenched galaxies in Simba cosmological hydrodynamic simulations, focusing on comparing HI metal line absorption to observations from COS-Halos COS-Dwarfs surveys. Halo baryon fractions are generally $\lesssim 50\%$ cosmic fraction due stellar feedback at low masses, jet-mode AGN high masses. Baryons m...