The addition of organic and inorganic substrates to calcareous soils low in organic matter and nitrogen contents may change soil microbial biomass and activity. In order to investigate the effect of chemical and organic fertilizers on soil CO2 production and microbial biomass C, a field experiment was conducted under maize cultivation. The experimental design was split-plot arranged in randomiz...

reinsurance is widely recognized as an important instrument in the capital management of an insurance company as well as its risk management tool. this thesis is intended to determine premium rates for different types of reinsurance policies. also, given the fact that the reinsurance coverage of every company depends upon its reserves, so different types of reserves and the method of their calc...

according to coates’s (2004, as cited in zhang, 2010) definition of "conversational dominance" (p.111), it refers to the phenomenon of a speaker dominating others in interaction. specifically, it means how a speaker makes use of certain strategies to get the floor and maintain the floor. thus, the amount of talk is the main measurement for the dominance of the conversation. whether a speaker do...

The presence of large amounts of calcium in the equilibrium system of calcareous soils of arid and semi-arid regions affects the chemical reactions of soluble and exchangeable phases. Exchange phenomenon is one of these chemical reactions in which calcium plays an important role. K-Ca equilibria are important equilibria in calcareous soils and may be an answer to many problems in soil chemistry...

asymmetric polyethersulfone (pes) microfiltration flat sheet membranes were composed by the phase inversion method (pim) and were used as supports. composite membranes were fabricated by coating silicone rubber as selective layer. effect of different concentrations of pes and pdms and different solvent such as nmp, dmf and dms effects as pes solvents and support thickness and different coagulat...

Cadmium (Cd) and its rate in soil have received lots of attention because it is easily taken up by plant root, making it 20 times more toxic in comparison with other heavy metals. Knowledge about the factors affecting Cd availability and conversion of its chemical forms is, therefore, important. Sequential extraction has been used as a suitable method for identification of chemical forms and th...

Soil contamination with heavy metals, including Cd and Pb, is of serious concern. The aim of this study was to investigate the efficiency of Atriplex verucifera, Salicornia europaea and Chenopodium album for simultaneous remediation of soil exchangeable sodium percentage and Cd and Pb contamination in two soils with different properties. Two soils, including a saline-sodic-calcareous (S1) and c...

abstract part one: the electrode oxidation potentials of a series of eighteen n-hydroxy compounds in aqueous solution were calculated based on a proper thermodynamic cycle. the dft method at the level of b3lyp-6-31g(d,p) was used to calculate the gas-phase free energy differences ,and the polarizable continuum model (pcm) was applied to describe the solvent and its interaction with n-hydroxy ...