Microstructural and magnetic characterization of dusts from a stone crushing industry in Birbhum, India

Stone dust sample collected from a stone crushing industry situated at Muhammad Bazar in Birbhum, India, is studied for its physical characterization using various techniques. Morphology and compositional analysis of the stone dust by scanning electron microscopy (SEM) reveal that the dust is an agglomeration of many tiny particles (0.32-2.12 μm), mostly having sharp edges, as well show microstructure heterogeneity. Elements present in the sample are detected by energy dispersive X-ray spectrometry (EDX). The X-ray diffraction (XRD) pattern analysis shows that the sample mainly contains minerals like anorthite, augite, esseneite and albite. An overall antiferromagnetic interaction in this sample has been indicated by the nature of the thermal dependence of magnetization. The remnant magnetization study apparently indicates two magnetic transitions at low temperatures. ⁵⁷Fe Mössbauer spectroscopy has been employed to detect different possible iron sites as well as to estimate the respective site population. In general, Mössbauer spectroscopic results corroborate the observations made through XRD analysis in general.     

A mathematical model to study the soil arching effect in stone column-supported embankment resting on soft foundation soil

Soil arching is a common phenomena in pile or columnar (vibroconcrete columns, soil–cement columns by mixing or grouting, stone columns) supported geosynthetic-reinforced or unreinforced embankments resting on soft soil. Due to soil arching, stress acting on soft soil or geosynthetic reinforcement decreases and stress on piles or columns increases. In this paper, using mechanical elements (such as spring, dashpot), a generalized mathematical model has been developed to study the soil arching effect in stone column-supported geosynthetic-reinforced and unreinforced embankments resting on soft soil. Pasternak model concept has been used to model the embankment soil. The soft soil has been idealized by spring-dashpot system to include the time-dependent behavior. The stone columns and geosynthetic reinforcement are idealized by stiffer nonlinear springs and rough elastic membrane, respectively. The consolidation effect of soft soil due to inclusions of stone columns has also been included in the model to study its effect on soil arching. Plane strain condition has been considered in the analysis. A finite difference scheme has been used to solve the governing differential equations and results are presented in non-dimensional form. It has been observed that the height of embankment, degree of consolidation of soft soil, stiffness of the stone column material, spacing between the stone columns, use of geosynthetic reinforcement and properties of soft and embankment soils (such as ultimate bearing capacity of soft soil, shear modulus and ultimate shearing resistance of embankment soil) significantly influence the degree of soil arching.     

R_0-代数的Stone拓扑表示定理

研究R0-代数中极大滤子的结构性质,通过引入有限平方交性质的概念证明了素理想定理;在全体极大滤子之集上引入了Stone拓扑,研究了Stone空间的性质;在R0-代数中引入了Boole-元的概念,证明了R0-代数的Stone拓扑表示定理,即,全体Boole-元作为Boole代数同构于该R0-代数的Stone空间中的全体既开又闭子集构成的Boole代数。Boole代数的Stone拓扑表示定理可作为该表示定理的特例而给出。     

The characterization of certain quantum stochastic stationary process

In this paper we will obtain a Stone type theorem under the frame of Hilbert C＊-module, such that the classical Stone theorem is our special case. Then we use it as a main tool to obtain a spectrum decomposition theorem of certain stationary quantum stochastic process. In the end, we will give it an interpretation in statistical mechanics of multi-linear response.     

电感耦合等离子体原子发射光谱（ICP-AES）法测定石煤钒矿石中钒、铁、钛的含量

研究一种快速准确测定石煤钒矿石中钒、铁、钛含量的方法对石煤钒矿检测行业的发展和石煤钒矿资源的开发利用、综合评价具有重要的意义。本研究试样经过氧化钠在650℃完全熔融后保持1-3min,取出冷却,热水浸提,盐酸酸化,定容稀释,选择V 292.402nm 、Fe 259.940nm 、Ti 334.941nm为分析谱线,利用电感耦合等离子体原子发射光谱法（ ICP-AES ）,建立了石煤钒矿石中同时测定钒、铁、钛含量的方法。试验优化了钒、铁、钛元素的分析谱线和背景校正模式,采用全程序样品空白稀释配置的校准曲线消除盐度钠基影响;研究了坩埚、熔剂种类、直接碱熔与灼烧-碱熔前处理方式、酸度效应的影响。结果表明,方法检出限为0.009%～0.019%,定量限为0.027%～0.057%;铁、钛、钒3元素浓度在0.10～30.0μg/mL时,校准曲线线性回归方程的相关系数均大于0.9999;采用国家一级标准物质（GBW 07876、GBW 07877、GBW 07878）进行验证,相对标准偏差( RSD%,n =12) 为 0.49～0.87,且测定值与标准值吻合。该方法具有快速简便、精密度好、准确度高、同时测定钒、铁、钛等优点,满足石煤钒矿石化学分析检测需求,且可为石煤钒矿化学分析标准方法的建立提供技术支撑。     

Endodualisable and endoprimal finite double Stone algebras

The finite endodualisable double Stone algebras are characterised, and every finite endoprimal double Stone algebra is shown to be endodualisable. Received February 24, 1999; accepted in final form May 10, 1999.