Strain Growth in Containment Vessels

Strain growth is a phenomenon observed in containment vessels subjected to internal blast loading. The elastic response of the vessel may become larger in a later stage compared to its response during the initial stage. The dynamic responses of infinitely long cylindrical containment vessels subjected to uniformly-distributed internal blast loading are studied using LS-DYNA. The development of bending modes and the interaction between the breathing mode and bending modes are observed. The methodology developed for dynamic elastic buckling analysis is employed to study the strain growth phenomenon in explosion containment vessels. It is shown that the dynamic instable vibration of a containment vessel is the basic mechanism of strain growth.     

On analysis of electrical engineering programme in GCC countries

Electrical engineering (EE) curricula in the Gulf Cooperation Council (GCC) region have gone through an evolutionary process, and are now approaching a maturity level. In order to address academic and local industrial needs in a unified way, a need has been felt to investigate EE curricula in a way that highlights theoretical understanding, design experience and skills development. This paper focuses on a comparative study of electrical EE programmes offered in various GCC region universities. The general and some focused programmes are analysed with respect to their breadth and depth. Using cluster analysis, we identify five major distinct EE programme clusters, each grouping a set of universities. This outlines where EE programmes in the GCC region are headed.     

Faculty salary analyses by region,rank, and discipline from 1977–1978 to 1983–1984

Although the limited past research on the effects of region on faculty salaries has presented inconsistent findings, it was expected that region would be significant in explaining faculty salaries over a seven-year period. The data had been collected from member institutions of the National Association of State Universities and Land-Grant Colleges in the annual faculty salary surveys during 1977–1978, 1980–1981, and 1983–1984. The data were weighted average salaries (N = 528) of new assistant, assistant, associate, and full professors in eleven grouped disciplines from four geographical regions. Analysis of variance was used to explain the variation in salaries by region, year, rank, and, to some extent, discipline. The significance level was set at .01. Year, rank, discipline, and the interaction of year and rank were found to be significant. The study revealed that since 1980 the ranges among salaries by region, rank, and discipline have been increasing.     

A New Statistic for Detection of Aberrant Answer Changes

As noted by Fremer and Olson, analysis of answer changes is often used to investigate testing irregularities because the analysis is readily performed and has proven its value in practice. Researchers such as Belov, Sinharay and Johnson, van der Linden and Jeon, van der Linden and Lewis, and Wollack, Cohen, and Eckerly have suggested several statistics for detection of aberrant answer changes. This article suggests a new statistic that is based on the likelihood ratio test. An advantage of the new statistic is that it follows the standard normal distribution under the null hypothesis of no aberrant answer changes. It is demonstrated in a detailed simulation study that the Type I error rate of the new statistic is very close to the nominal level and the power of the new statistic is satisfactory in comparison to those of several existing statistics for detecting aberrant answer changes. The new statistic and several existing statistics were shown to provide useful information for a real data set. Given the increasing interest in analysis of answer changes, the new statistic promises to be useful to measurement practitioners.