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The study on decreasing ammonia-nitrogen has received great attention in recent years. This paper summarizes the adsorption mechanism and the influencing factors. Thus, the feasibility of adsorption using biochar has been indicated. A few issues were proposed for the further study: the industrial application research on treatment, modification method for improving the efficiency of adsorption, desorption and regeneration of biochar ,model of adsorption mechanism, the physical and chemical properties of soil .

In order to investigate envelopes for singular surfaces, we introduce one- and two-parameter families of framed surfaces and the basic invariants, respectively. By using the basic invariants, the existence and uniqueness theorems of one- and two-parameter families of framed surfaces are given. Then we define envelopes of one- and two-parameter families of framed surfaces and give the existence conditions of envelopes which are called envelope theorems. As an application of the envelope theorems, we show that the projections of singular solutions of completely integrable first-order partial differential equations are envelopes. [ABSTRACT FROM AUTHOR]

In this paper, we introduce a one-parameter family of Legendre curves in the unit spherical bundle over the unit sphere and the curvature. We give the existence and uniqueness theorems for one-parameter families of spherical Legendre curves by using the curvatures. Then we define an envelope for the one-parameter family of Legendre curves in the unit spherical bundle. We also consider the parallel curves and evolutes of one-parameter families of Legendre curves in the unit spherical bundle and their envelopes. Moreover, we give relationships among one-parameter families of Legendre curves in the unit spherical bundle over the unit sphere and one-parameter families of Legendre curves in the unit tangent bundle over the Euclidean plane. [ABSTRACT FROM AUTHOR]

The article discusses the results of a study on the preparation and properties of a covalently functionalized organoclay and its polypropylene (PP) nanocomposite. A condensation reaction between sodium hydroxyl groups and acryloyl chloride was used to prepare organoclay which was then modified through ion exchange with hexadecyltrimethylammonium bromide. PP nanocomposites loaded with organoclay were produced by melt mixing. The composites showed improved higher storage modulus and viscosity.

Abstract: The effect of combination between a trace of halogenated compounds (such as ferric chloride and ammonium bromide) and Ni2O3 particles on the carbonization of polypropylene (PP) was investigated during combustion. The results showed a synergistic catalysis of combined halogenated compounds with Ni2O3 in promoting the formation of the residual char during combustion. The investigation on the promotion mechanism showed that halide radical releasing from halogen-containing additives worked as a catalyst to accelerate dehydrogenation–aromatization of degradation products of PP, which promote the degradation products to form the residual char catalyzed by nickel catalyst. The results of GC and GC/MS confirmed that halogenated compounds could accelerate dehydrogenization and aromatization of degradation products of PP. The morphological observation showed that longer fiber-like structure was formed in the residual char of PP/halogenated compound/Ni2O3 composites comparing with PP/Ni2O3 composite. As a result, the presence of a trace amount of halogenated compounds could significantly improve the flame retardancy of PP/Ni2O3 composites, which is proved by cone calorimeter tests. [Copyright &y& Elsevier]