From the early Copper Age several millennia ago, to the beginning of the Steel Age in the 19th century, our capacity to access and manipulate metals has created the foundation for the modern world. Today, metal structures are ubiquitous— from the tallest skyscrapers to the most elegant of jewelry—that we often forget much of it originated from metal containing ores, comprised of metal compounds...

Context. High-mass star-forming regions are known to have a rich molecular spectrum from many species. Some of the very highly excited lines are emitted from very hot and dense gas close to the central object(s). Aims. The physics and chemistry of the inner cores of two high mass star forming regions, NGC6334(I) and G327.3-0.6, shall be characterized. Methods. Submillimeter line surveys with th...

The detection of X-ray emission from Hickson's compact groups of galaxies (HCGs) and its origin are the subject of this work. A search for X-ray emission from compact groups revealed detection from 8 out of the 12 HCG images extracted from the ROSAT public archive. For two of them (HCG16 and HCG44), the Xray emission originates from point-like sources spatially coincident with galaxies in the g...

Since the chemical evolution of galaxies seems to differ between morphological types and deviates in many details from the standard scenario the question has to be addressed when, how and to what amount metal-enriched ejecta from Supernovae and Planetary Nebulae polute their environment. Since recent observations of dwarf galaxies show no significant metal abundance gradients throughout the gal...

Single point incremental sheet metal forming is a sheet metal forming process that forms products without the complex dies and tools with low cost. In this study, the incremental sheet metal forming process has been experimentally investigated on the explosively-welded Al/Cu bimetal sheets. Also, the effects of process parameters, such as arrangement of layer`s bimetal, tool diameter and tool p...

I review the arguments motivating models for massive star formation via stellar collisions. I then describe how the standard accretion scenario, involving the collapse of a quasi-hydrostatic gas core, can produce high-mass stars in the pressurized regions of forming star clusters. I argue that the observational evidence, particularly in the Orion hot core, favors the standard accretion paradigm.

Heat-resisting alloys are designed to survive high-temperature oxidation by forming a slow-growing scale, usually Cr 2 O 3 , which acts as barrier between the metal and its environment. However, that succeed in this way when exposed hot oxygen or air fail do so CO gas. Instead, they exhibit rapid “breakaway” corrosion, developing oxides of alloy base iron and/or nickel. The growth these non-pro...