Experimental study on fluidization of micronic powders

The fluidization behavior of yttrium oxide (Y2O3) powders of high density and micronic diameter belonging to the group C of Geldart’s classification has been investigated. Large interparticle forces lead to bed cracking, slugging and channelling, and cause the powder not to fluidize consistently. Different fluidization technologies have been tested, such as mechanical agitated fluidization, vibrated fluidization and addition of easyto-fluidize large particles to fine particles. The quality of fluidization has been studied through pressure drop diagrams for decreasing gas velocities and for various fixed bed heights to column diameter ratios. In the case of stirred fluidization, several stirrer geometries have been tested (helix, turbine, etc.). However, the fluidization has not been satisfactory. By adding larger particles to fine powders, convenient fluidization conditions have been obtained. An inertia effect proportional to the initial bed weight seems to contribute to fluidization. Some evaluation of interparticle forces governing the tested mixture of fine/large particles has been performed by studying the influence of mass percentage of fine particles on the Hausner ratio and the angle of repose. Fluidization under vibration allows to partly overcome the adhesion forces between powders. The fluidization behavior has been improved for the highest vibration strengths

Glyco-biomarkers: Potential determinants of cellular physiology and pathology

Once dismissed as just the icing on the cake, sugar molecules are emerging as vital components in life’s intricate machinery. Our understanding of their function within the context of the proteins and lipids to which they are attached has matured rapidly, and with it the far reaching clinical implications are becoming understood. Recent advances in high-throughput glycomic techniques, glyco biomarker profiling, glyco-bioinformatics and development of increasingly sophisticated glyco-arrays, combined with our increased understanding of the molecular details of glycosylation have facilitated the linkage between aberrant glycosylation and human diseases, and highlighted the possibility of using glyco-biomarkers as potential determinants of disease and its progression. The focus of this review is to give an insight into the biological significance of these glycomodifications, highlight some specific examples of glyco-biomarkers in relation to autoimmunity and in particular rheumatoid arthritis, and to explore the exciting possibility of exploiting these for diagnostic and prognostic strategies

Quantum corrections to conductivity for semiconductors with various structures

We study the magnetic field dependences of the conductivity in heavily doped, strongly disordered 2D quantum well structures within wide conductivity and temperature ranges. We show that the exact analytical expression derived in our previous paper [1], is in better agreement than the existing equation i.e. Hikami(et.al.,) expression [2,3], with the experimental data even in low magnetic field for which the diffusion approximation is valid. On the other hand from theoretical point of view we observe that our equation is also rich because it establishes a strong relationship between quantum corrections to the conductivity and the quantum symmetry su_{q}(2). It is shown that the quantum corrections to the conductivity is the trace of Green function made by a generator of su_{q}(2)algebra. Using this fact we show that the quantum corrections to the conductivity can be expressed as a sum of an infinite number of Feynman diagrams.Comment: 15 pages, 6 figures. To appear in International journal of modern physics

Large subgroups of simple groups

Let $G$ be a finite group. A proper subgroup $H$ of $G$ is said to be large if the order of $H$ satisfies the bound $|H|^3 \ge |G|$. In this note we determine all the large maximal subgroups of finite simple groups, and we establish an analogous result for simple algebraic groups (in this context, largeness is defined in terms of dimension). An application to triple factorisations of simple groups (both finite and algebraic) is discussed.Comment: 37 page