76 research outputs found

    Knot homology via derived categories of coherent sheaves II, sl(m) case

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    Using derived categories of equivariant coherent sheaves we construct a knot homology theory which categorifies the quantum sl(m) knot polynomial. Our knot homology naturally satisfies the categorified MOY relations and is conjecturally isomorphic to Khovanov-Rozansky homology. Our construction is motivated by the geometric Satake correspondence and is related to Manolescu's by homological mirror symmetry.Comment: 51 pages, 9 figure

    Use of low-energy electron-beam in the treatment of special food products with a high protein content

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    Special high-protein foods suitable for diabetics must be treated to ensure the complete absence of microorganisms and bacteria. It is also important to achieve that this treatment does not change the nutritional value of the product. Among the new decontamination technologies, low-energy electron-beam treatment has proven to be an effective technique for inactivating bacteria with minimal impact on food quality. The paper aims to analyze the influence of low-energy electron-beam irradiation on the microbiological properties and nutritional value of high-protein foods

    Radiological and physico-chemical characterization of red mud as an Al-containing precursor in inorganic binders for the building industry

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    The potential re-use of red mud in the building and construction industry has been the subject of research of many scientists. The presented research is a contribution to the potential solution of this environmental issue through the synthesis of potential construction materials based on red mud. A promising way of recycling these secondary raw materials is the synthesis of alkali-activated binders or alkali activated materials. Alkali-activated materials or inorganic binders based on red mud are a new class of materials obtained by activation of inorganic precursors mainly constituted by silica, alumina and low content of calcium oxide. Since red mud contains radioactive elements like 226Ra and 232Th, this may be a problem for its further utilization. The content of naturally occurring radionuclides in manufactured material products with potential application in the building and construction industry is important from the standpoint of radiation protection. Gamma radiation of the primordial radionuclides, 40K and members of the uranium and thorium series, increases the external gamma dose rate. However, more and more precedence is being given to limiting the radiological dose originating from building materials on the population these days. The aim of this research was to investigate the possible influence of alkali activation-polymerization processes on the natural radioactivity of alkali activated materials synthesized by red mud (BOKSIT a. d. Milići, Zvornik, Bosnia and Herzegovina) and their structural properties. This research confirmed that during the polymerization process the natural radioactivity was reduced, and that the process of alkali activation of raw materials has an influence on natural radioactivity of synthesized materials

    The hypertoric intersection cohomology ring

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    We present a functorial computation of the equivariant intersection cohomology of a hypertoric variety, and endow it with a natural ring structure. When the hyperplane arrangement associated with the hypertoric variety is unimodular, we show that this ring structure is induced by a ring structure on the equivariant intersection cohomology sheaf in the equivariant derived category. The computation is given in terms of a localization functor which takes equivariant sheaves on a sufficiently nice stratified space to sheaves on a poset.Comment: Significant revisions in Section 5, with several corrected proof

    Computed tomography image using sub-terahertz waves generated from a high-T-c superconducting intrinsic Josephson junction oscillator

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    A computed tomography (CT) imaging system using monochromatic sub-terahertz coherent electromagnetic waves generated from a device constructed from the intrinsic Josephson junctions in a single crystalline mesa structure of the high-T-c superconductor Bi2Sr2CaCu2O8+delta was developed and tested on three samples: Standing metallic rods supported by styrofoam, a dried plant (heart pea) containing seeds, and a plastic doll inside an egg shell. The images obtained strongly suggest that this CT imaging system may be useful for a variety of practical applications

    Efficient separation of Tc-99 from aqueous solution using pinecone activated carbon

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    Sorption of radioactive 99Tc-pertechnetate onto activated carbon prepared from pinecones was investigated. The parameters of contact time and Tc-99 concentration were varied. It was established that the sorption half-life, t1/2, was very short ~ 2.2 min, thus making this sorbent an excellent candidate for immediate pollution remediation, which is very important in the case of nuclear accidents. The kinetic data were found to follow closely the pseudosecond- order (PSO) kinetic model. Boyd model established the sorption dependence only on film diffusion. The partitioning/distribution coefficient, Kd, attained was 2729 cm3 g-1. The equilibration time was 3 h at room temperature (T=298 K)

    Structural and Chemical Properties of Geopolymer Gels Incorporated with Neodymium and Samarium

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    The present work was focused on doping of 1% and 5% both of Nd2O3 and Sm2O3 in geopolymer gels. One of the main goals was to determine the influence of the behavior of Nd and Sm as dopants and structural nanoparticles changes of the final geopolymer formed. It is shown that the disorder formed by alkali activation of metakaolin can accommodate the rare earth cations Nd3+ and Sm3+ into their aluminosilicate framework structure. The main geopolymerization product identified in gels is Al-rich (Na)-AS-H gel comprising Al and Si in tetrahedral coordination. Na+ ions were balancing the negative charge resulting from Al3+ in tetrahedral coordination. The changes in the structures of the final product (geopolymer/Nd2O3; Sm2O3), has been characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analysis with energy dispersive spectrometry (EDS). Nucleation at the seed surfaces leads to the formation of phase-separated gels from rare earth phase early in the reaction process. It is confirmed that Nd and Sm have been shown to form unstable hydroxides Nd(OH)3 and Sm(OH)3 that are in equilibrium with the corresponding oxides

    Synthesis and characterization of Brushite-metakaolin-based geopolymer materials

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    In a field of green chemistry, environmental protection and ecological conservation of the environment there are ways to come up with new and more advanced materials using on the one hand natural, recyceled or waste materials and on the other hand syntethic materials obtained by using green chemistry synthesis procedures. The aim of this paper was to synthesize and characterize Brushite-metakaolin-based geopolymer materials and to examine the possibility of using these materials in the fields of construction, cement industry, as well as in environmental protection as potential adsorbents. Initial materials which were used for geopolymer synthesis was Brushite (CaHPO4·2H2O) which was obtained by solutionprecipitation reaction form acetate solutions and Kaolinite clay from Rudovci deposit (Serbia). The obtained mixture powders were dissolved in a strong alcaline solution with addiction of water glass. Produced geopolymers was cast into mods and preserved for 28 days. The starting materials and the synthesized Brushite-metakaolin-based geopolymer material were examined using XRPD, FTIR SEM-EDS methods. The contact angle measurements were made to test hydrophilic and wettable properties of synthesized material

    Geometric Satake, Springer correspondence, and small representations

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    For a simply-connected simple algebraic group GG over \C, we exhibit a subvariety of its affine Grassmannian that is closely related to the nilpotent cone of GG, generalizing a well-known fact about GLnGL_n. Using this variety, we construct a sheaf-theoretic functor that, when combined with the geometric Satake equivalence and the Springer correspondence, leads to a geometric explanation for a number of known facts (mostly due to Broer and Reeder) about small representations of the dual group.Comment: Version 2: minor revisions, 33 page
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