The role of thermal analysis in detecting impurity levels during aluminum recycling

Recycling of aluminum scrap has gained interest owing to its economic and ecological benefits. Unfortunately, during the collection of scrap from a mixer of junk from various sectors it is difficult to ensure that the recycled alloy has the same chemical composition as that of already existing commercial alloys. Consequently, some of the alloying elements become trace/tramp elements in the recycled alloy. Therefore, in order to obtain high performance recycled alloys, controlling the impurity levels of the aluminum melt is of vital importance. Normally, computer aided cooling curve analysis (CA-CCA) is used to find the relationship between cooling curve parameters, melt treatments, alloy composition, and properties. In the present study, the first differential thermal analysis (DTA) approach has been used to detect and quantify impurity elements in scrap-like liquid aluminum alloys.     

Threshold gain analysis of second order distributed feedback lasers based on [2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene]

We present a theoretical study of the threshold analysis of second order surface emitting distributed feedback lasers based on the polymer [2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV). A coupled mode formalism that includes radiation modes is used to describe the propagation of the waves in the periodically corrugated region. A detailed calculation of the threshold gain of the laser that includes the effects of the radiation modes is described.