Quantum molecular similarity ~QMS! techniques are used to assess the response of the electron density of various small molecules to application of a static, uniform electric field. Likewise, QMS is used to analyze the changes in electron density generated by the process of floating a basis set. The results obtained show an interrelation between the floating process, the optimum geometry, and th...

The fundamental understanding of the deformation behavior of electromagnetically formed metallic components under extreme conditions is important. Here, the effect of low temperature on the deformation behavior of an electromagnetically-bulged 5052 aluminum alloy was investigated through uniaxial tension. We found that the Portevin-Le Chatelier Effect, designated by the serrated characteristic ...

The well-known definition of disease, which Samuel Hahnemann presented while making a challenge to provide a tentative theory for his new science and art of healing, is used as a starting point for the model. The biochemical equilibrium is used for a demonstration of the Le Chatelier–Braun principle and/or the Guldberg–Waage Law in order to clarify the principles and to explain the well-known “...

the effect of interstitial atoms upon portevin _ le chate1ier phenomena, are theoretically and experimentally investigated as a manifestation of the cottrell effect. in presence of substitutional atoms, because of their very smaller diffusion coefficient, the condition is more complicated. in this article the behaviour of substituflonal atoms in the beryllium and a few fe alloys, on portevin-le...

An experimental study is presented on the effect of microstructural change on the Portevin-Le Chatelier effect behaviour of Al-2.5%Mg alloy. Tensile tests are performed on the as received and heat treated (at 400 oC for 16 hours) samples for a wide range of strain rates. The serrations observed in the stress-time curve are investigated from statistical analysis point of view. Microstructures of...

Misconceptions are among the main topics of interest in chemistry education. One points emphasized while analyzing causes misconceptions is epistemological difficulties. The point analyzed here pertains to difficulties caused by nature concepts or their misconceptions. However, concept itself can sometimes be source misconception due its ambiguities which turn leads hesitation whether that shou...

The Bayer Process (for alumina) as we know it today involves two steps: • The pressure leaching of bauxite with NaOH solution to obtain sodium aluminate solution. • The precipitation of pure aluminum hydroxide from this solution by seeding with fine crystals of Al(OH)3 . The leaching step was invented five years after the precipitation step (Table 1), and the precipitation step was an improveme...

A technique based on high-speed digital photography and image correlation for direct whole-field strain mapping of Portevin–Le Chatelier deformation bands is described. Results for a type B band show that the deformation band was formed within a few milliseconds and remained stationary as no motion of the band was detected. 2005 Published by Elsevier Ltd. on behalf of Acta Materialia Inc.

A thermodynamics of open systems has been developed which provides an entirely new theoretical framework based on novel concepts without any recourse to statistical mechanics, The standard chemical potential is replaced by a convective potential itself derived from a new concept referred to as the “thermobaric potential”. Entropy convected by addition of masses into an open system is obtained u...