The radio lobes of the radio galaxy Hercules A contain intriguing ring-like structures concentric with the jet axis. To investigate the occurrence of such features, we have used hydrodynamic simulations of jets with a range of Mach numbers (fromM = 2 to 50) and densities (down to a ratio of 10 relative to the background) to generate ray-traced images simulating synchrotron emission from the tim...

[1] Magnetic helicity, a conserved topological parameter in ideal MHD systems, conditions close to which are realized in the solar plasma, is intimately connected to the creation and subsequent dynamics of magnetic flux tubes in the solar interior. It can therefore be used as a tool to probe such dynamics. In this paper we show how photospheric observations of magnetic helicity of isolated magn...

Hydrodynamic of a turbulent impinging jet on a flat plate has been studied experimentally and numerically. Experiments were conducted for the Reynolds number range of 72000 to 102000 and a fixed jet-to-plate dimensionless distance of H/d=3.5. Based on the experimental setup, a multi-phase numerical model was simulated to predict flow properties of impinging jets using two turbulent models. Mesh...

in this study, friction stir spot welding (fssw) is applied to join the tial6v4 titanium alloy with 1.5 mm thickness and then the effect of rotational speed and tool dwell time on microstructure and mechanical properties is investigated. in this regard, the speed of the tool rotation was considered as 800, 1000, and 1200 rpm, as well as the tool dwell time was set at 7 and 12s. microstructural ...

resistance spot welding is an important manufacturing process in the automotive industry for assembling bodies. the quality and strength of the welds and, by extension, the body is mainly defined by the quality of the weld nuggets. the most effective parameters in this process are sheet material, geometry of electrodes, electrode force, current intensity, welding time and sheet thickness. the p...

forest types mapping, is one of the most necessary elements in the forest management and silviculture treatments. traditional methods such as field surveys are almost time-consuming and cost-intensive. improvements in remote sensing data sources and classification –estimation methods are preparing new opportunities for obtaining more accurate forest biophysical attributes maps. this research co...

viral symptoms indicative of iris yellow spot virus (iysv) were observed on onion in several fields near chenaran in khorasan razavi province. mechanical inoculation of herbaceous hosts with onion sap extracts from symptomatic plants showed similar symptoms to those described for iysv. the mechanically transmitted virus reacted only with antisera specific to iysv in das-elisa but not with antis...

bipolaris oryzae causes rice brown spot disease which reduces rice yield with substantial global impact. streptomycetes isolated from rice fields of guilan province, iran, showed antifungal activity against the tested pathogen. from five active streptomyces spp. isolates, isolate g showed high antagonistic activity. to determine its taxonomical identity, its colonies characterized morphological...

background: a variable resolution x-ray (vrx) ct scanner provides a great increase in the spatial resolution. in vrx ct scanners, the spatial resolution of the system and its field of view (fov) can be changed according to the object size. one of the main factors that limit the spatial resolution of vrx ct scanner is the effect of the x-ray focal spot. materials and methods: a theoretical study...