descargar gratis libro conceptos de administracion estrategica fred david

In this article, we estimate the performance of control charts derived under the assumption of normality (normal charts) but used with a much broader range of distributions. In such cases the use of traditional control charts may not be effective. Although this may be adequate for many processes, there are situations where these basic assumptions do not hold. Most control charts for variables data are constructed and analyzed under the assumption that observations are independent and normally distributed.

The negative values of EHOMO and the estimated value of the Standard Free Gibbs energy for all the molecules (based on the calculated equilibrium constant) were negative, indicating that the complete chemical processes in which the inhibitors are involved, occur spontaneously In this work, from a theoretical study a correlation was found between EHOMO, hardness (η), electron charge transfer (ΔN), electrophilicity (W), back-donation (ΔEBack-donation) and the inhibition efficiency, IE. This fact strongly suggests that, contrary to a hitherto generally suggested notion, an efficient corrosion inhibiting molecule neither requires to be a large one, nor possesses an extensive π-electrons number. Thus 2MI turned out to be the best inhibitor.

Acta, 54, (2009) 539), it was found that the corrosion inhibition efficiency, IE, order followed by the molecules tested was 2MI > 2MBI > 2M5MBI > 2M5NBI. From an electrochemical study conducted previously in our group, (R. In order to analyze the influence of substituent groups, both electron-donating and electron-attracting and the number of π-electrons on the corrosion inhibiting properties of organic molecules, a theoretical quantum chemical study under vacuo and in the presence of water, using the Polarizable Continuum Model (PCM), was carried out for four different molecules, bearing similar chemical framework structure: 2-mercaptoimidazole (2MI), 2-mercaptobenzimidazole (2MBI), 2-mercapto-5- methylbenzimidazole (2M5MBI), and 2-mercapto-5-nitrobenzimidazole (2M5NBI).

Descargar gratis libro conceptos de administracion estrategica fred david