Sixteen-fermion and related terms in M-theory on T**2

Certain one-loop processes in eleven-dimensional supergravity compactified on T**2 determine exact, non-perturbative, terms in the effective action of type II string theories compactified on a circle. One example is the modular invariant U(1)-violating interaction of sixteen complex spin-1/2 fermions of ten-dimensional type IIB theory. This term, together with the (curvature)**4 term, and many other terms of the same dimension are all explicitly related by supersymmetry.Comment: 14 Pages, Latex, no figures, Minor changes, version to appear in PL

Master of Science

thesisThe contents of impurities, especially that of phosphorus, in manganese metal or in ferromanganese used in steelmaking are an important factor that affects product quality. More than 80% of phosphorus in the manganese products is introduced from manganese ore, the rest coming from coke and lime. Once it is absorbed into a molten manganese ore ferromanganese phase, it cannot be easily removed by smelting, and thus, ferromanganese must generally be low in phosphorus to begin with. As good quality ores of low phosphorus are depleted, the phosphorus content in manganese ores increases, and thus, the development of a new dephosphorization technology is needed. For this purpose, the removal of phosphorus compounds by vaporization directly from manganese ores using a plasma system was investigated in this study. For the removal of phosphorus, the effects of argon gas flow rate, hydrogen gas content in the plasma gas, and plasma torch power were analyzed. In addition, based on the thermal decomposition of hematite in the ores into magnetite at a high temperature, a magnetic separation was conducted after plasma treatment aiming to upgrade manganese ores. For the removal of phosphorus, a low argon gas flow rate and a high torch power were found to be effective, and the use of hydrogen gas as a reducing agent was more favorable than without. Magnetic separation after plasma treatment improved the ore grade with a decrease of iron content in the ore

A Quantitative Framework Of Skill Evaluation of IT Workforce

Every employee has different abilities as well as experience, leading to different results in terms of skills and job performance. In order to improve employee IT skills, organizations should evaluate their employees\u27 skills to understand the current levels of skills and knowledge and to figure out areas where skills are currently lacking. This study used a different approach than other existing methods to evaluate the IT skills of employees. The research used quantitative empirical data that represents the work experience of employees based on their task history and job positions. The suggested method defines the relationship between IT skills and IT task activities and between IT skills and job positions. The numerical analysis method was made and used to calculate scores that express the level of work experience and skills of employees. A tool was developed with computer programming in order to embody the method and make the best use of the method, and case studies were performed in order to test the validity of the method with three cases. According to results of the case study, the same or similar skills were estimated in accordance with the same or similar work experience

BPS D-branes from an Unstable D-brane in a Curved Background

We find exact tachyon kink solutions of DBI type effective action describing an unstable D5-brane with worldvolume gauge field turned on in a curved background. The background of interest is the ten-dimensional lift of the Salam-Sezgin vacuum and, in the asymptotic limit, it approaches ${\rm R}^{1,4}\times {\rm T}^2\times {\rm S}^3$. The solutions are identified as composites of lower-dimensional D-branes and fundamental strings, and, in the BPS limit, they become a D4D2F1 composite wrapped on ${\rm R}^{1,2}\times {\rm T}^2$ where ${\rm T}^2$ is inside ${\rm S}^3$. In one class of solutions we find an infinite degeneracy with respect to a constant magnetic field along the direction of NS-NS field on ${\rm S}^3$.Comment: 16 pages, 2 figures, a footnote added, typos corrected and a reference adde