Elemental composition of Sal forest soils around Chhotanagpur Plateau,India

In recent decades, the Sal-dominated tropical deciduous forests (TDFs) were experiencing loss of regeneration due to lack of seed germination of native species. To understand this ecological problem, the present study dealt with the spatial and temporal variations in biogeochemical parameters of Sal forest soils. Twenty soil samples were collected from four TDF sites in the Chota Nagpur Plateau, India. The inventories of tree species in three life-cycle stages (seedling, sapling and adult) were carried out in four sites. Site-I (290?stems?ha^?1) showed occurrence of only one species (Shorea robusta) without seedling and sapling. The pH of forest soils was acidic to slightly acidic in nature. Seasonal variations in C/N ratio showed rapid mineralization of organic matter in the rainy season. ANOVA revealed that the degree of seasonal variation caused significant difference in pH, soil organic carbon, soil organic matter, total carbon, Al, Fe, Ca, Mg, Mn and P across four sites. The strong correlation of P with pH, Al, Fe, Mg and Mn indicated highly oxidised and exchangeable nature of dry forest soils. Factor analysis of soil parameters revealed that the different combinations of edaphic conditions in different seasons were important in the distribution of the dry tropical forests communities in Chota Nagpur Plateau.     

两种铝盐处理纸浆CEH漂白废水的混凝特性的研究

运用Ｚｅｔａ电位测定技术研究了聚合铝ＰＡＣ、聚硅铝ＰＳＡ两种不同形态铝盐对漂白废水絮凝反应特性，通过絮凝过程中Ｚｅｔａ电位及傅立叶红外光谱对原水及两种铝盐沉淀物进行了分析，结果表明：吸附架桥为其反应的主要机理，两种铝盐与漂白废水中污染物之间反应均以铝的羟基化合物与漂白废水中氯化木素氢键缔合的形式相结合     

A comparative study between two ignition sources: Electric igniter versus pyrotechnic igniter

The risk assessment of combustible explosive dust is based on the determination of the probability of dust dispersion, the identification of potential ignition sources and the evaluation of explosion severity. It is achieved in most of cases with the two main experimental normalized devices such as the Hartmann tube (spark ignition) and the 20 L spherical bomb (with two 5 kJ pyrotechnic ignitors).Ignition energy of the 5 kJ ignitor is well calibrated and generates a reproducible ignition. But, on the other hand, this ignition is not punctual and the over pressure produced is nearly 2 bar. Moreover, the pyrotechnic igniter accelerates the combustion with multi ignition points in a large volume and that disturbs the flame propagation. In this way, this ignition source does not allow to analyze the combustion products because the composition of the pyrotechnic igniter was found in the combustion products.This paper deals with the comparison of two ignition sources in the 20 L spherical bomb. Different explosive dusts of great industrial interest are studied with electrical and pyrotechnic ignitors, in order to understand, first, the influence of each type of igniter on the explosion behaviour and then to evaluate the possibility of establishing a correspondence between parameters obtained with these two ignition sources.Severity parameters of nicotinic acid, aluminium powder and titanium alloy were measured by using the two types of ignition system in our 20 L spherical bomb equipped with the Kühner dihedral injector. The explosion overpressure $\mathrm{P}$ and the rate of pressure rise $\left(\raisebox{1ex}{$dP$}\!\left/ \!\raisebox{-1ex}{$dt$}\right.\right)$ were measured in a large range of concentration allowing to propose correlations between electrical and pyrotechnic ignition for each parameter and each type of powder. These correlations aim to link the tests used with two different collections of experimental parameters for the same dust. The relevance of these correlations will be discussed.