We examined more than fifty indurated sediments recovered from the Central Indian Ocean Basin （CIOB） during the course of collection for manganese nodules and crusts. The samples occur as slabs either over which fer...We examined more than fifty indurated sediments recovered from the Central Indian Ocean Basin （CIOB） during the course of collection for manganese nodules and crusts. The samples occur as slabs either over which ferromanganese oxides are present or over a substrate of altered oceanic basalt in conjunction with palagonite or within the nucleus of manganese nodules. Mineralogically and compositionally, the samples show a mixture of phillipsite, palagonite and montmorillonite. We suggest that the volcanogenic precursors occurring in the CIOB were subjected to varying degrees of alteration under the influence of low temperature conditions, resulting in the formation of zeolitic claystones. The CIOB samples have similarities to those reported from various sites in the world oceans.展开更多
The rheological behavior of the semi-solid Ti B2 reinforced Al-Mg alloy composite slurry was investigated,which is required for the mould filling simulations during the semi-solid processing.Ti B2 reinforced in-situ A...The rheological behavior of the semi-solid Ti B2 reinforced Al-Mg alloy composite slurry was investigated,which is required for the mould filling simulations during the semi-solid processing.Ti B2 reinforced in-situ Al-Mg alloy composite samples were remelted and subsequently brought to the semi-solid temperature regime within the heating chamber of a Searle type rheometer.In order to understand the rheological behavior of composites,three different types of experiment were carried out,namely,steady state test,continuous cooling test and isothermal test.Apart from that,the thixotropic nature of the slurry was confirmed from the obtained hysteresis loops during the experimentation.The results indicate that when isothermally held,the composite slurry exhibits pseudo-plasticity and shows shear-thinning behavior up to the shear rate of 1300 s^-1,and at higher shear rates（1300 s^-1）,it shows a shear thickening tendency,which is probably due to the agglomeration of non-deformable nano-Ti B2 particles.The pseudo-plastic behavior of the slurry was also estimated employing intermittent step changes of shear rate（shear jump test）.展开更多
Oscillation criteria for the delay differential equationwhere p, T are non-negative real-valued continuous functions are investigated in the case when the numberssatisfy 0 < k < 1/e and 1/e < L < 1. The pr...Oscillation criteria for the delay differential equationwhere p, T are non-negative real-valued continuous functions are investigated in the case when the numberssatisfy 0 < k < 1/e and 1/e < L < 1. The present result improves almost all results of the literature concerning it. Furthermore, it is established that all solutions of the odd-order neutral delay differential equationwhere , are oscillatory ifThis result generalizes a theorem of Gopalsamy et. al (Czech. Math. J., 42 (1992),313-323) and also extends a very well-known result of Ladas (Applicable Analysis, 9(1979),93-98).展开更多
文摘We examined more than fifty indurated sediments recovered from the Central Indian Ocean Basin （CIOB） during the course of collection for manganese nodules and crusts. The samples occur as slabs either over which ferromanganese oxides are present or over a substrate of altered oceanic basalt in conjunction with palagonite or within the nucleus of manganese nodules. Mineralogically and compositionally, the samples show a mixture of phillipsite, palagonite and montmorillonite. We suggest that the volcanogenic precursors occurring in the CIOB were subjected to varying degrees of alteration under the influence of low temperature conditions, resulting in the formation of zeolitic claystones. The CIOB samples have similarities to those reported from various sites in the world oceans.
文摘The rheological behavior of the semi-solid Ti B2 reinforced Al-Mg alloy composite slurry was investigated,which is required for the mould filling simulations during the semi-solid processing.Ti B2 reinforced in-situ Al-Mg alloy composite samples were remelted and subsequently brought to the semi-solid temperature regime within the heating chamber of a Searle type rheometer.In order to understand the rheological behavior of composites,three different types of experiment were carried out,namely,steady state test,continuous cooling test and isothermal test.Apart from that,the thixotropic nature of the slurry was confirmed from the obtained hysteresis loops during the experimentation.The results indicate that when isothermally held,the composite slurry exhibits pseudo-plasticity and shows shear-thinning behavior up to the shear rate of 1300 s^-1,and at higher shear rates（1300 s^-1）,it shows a shear thickening tendency,which is probably due to the agglomeration of non-deformable nano-Ti B2 particles.The pseudo-plastic behavior of the slurry was also estimated employing intermittent step changes of shear rate（shear jump test）.
文摘Oscillation criteria for the delay differential equationwhere p, T are non-negative real-valued continuous functions are investigated in the case when the numberssatisfy 0 < k < 1/e and 1/e < L < 1. The present result improves almost all results of the literature concerning it. Furthermore, it is established that all solutions of the odd-order neutral delay differential equationwhere , are oscillatory ifThis result generalizes a theorem of Gopalsamy et. al (Czech. Math. J., 42 (1992),313-323) and also extends a very well-known result of Ladas (Applicable Analysis, 9(1979),93-98).
