Journal of Geochemistry The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Electro-Thermal and Semiconductivity Behaviour of Natural Sintered Complex Carbonate Ore for Thermo-Technological Applications Wed, 05 Mar 2014 09:38:15 +0000 The polymetal (Zn, Pb, Fe, Ca, Mg, Cd, Ba, Ni, Ti, and SiO2) complex Umm-Gheig carbonate ore is subjected to sintering treatment at 573, 773, 973 and 1273 K respectively for four hours. Chemical, spectral, X-ray and differential thermal analyses are applied for the native ore as well as for the samples preheated and sintered. The current versus applied DC voltage (–) characteristics, bulk density , percent shrinkage (%), activation energy and energy gap are established for the sintered ore. The electrical conductivity , thermal conductivity () and thermoelectric power coefficient have been investigated as a function of applied temperature for the sintered ore materials. The electrical conduction is mainly achieved by free electrons near or in conduction band or n-type. As the sintering temperature increases the conduction of the ore is also increased due to the recombination process taking place between the electrons and holes. Electrons hopping between Fe2+ and Fe3+ are the main charge carriers. The formation of Fe3O4 at high sintering temperature acts as an active mineralizer, thus inducing an increased degree of crystallinity and a more ordered crystal structure is produced. Loutfy H. Madkour Copyright © 2014 Loutfy H. Madkour. All rights reserved. Spatial Distributions of Humic Substances and Evaluation of Sediment Organic Index on Lake Dalinouer, China Thu, 02 Jan 2014 08:25:59 +0000 The aim of this study is to examine and interpret the spatial distribution of sedimentary humic substances in Lake Dalinouer. Humic substances in sediments were analyzed separately in different fractions: humins (HM), humic acid (HA), fulvic acid (FA), and different forms of organic carbon. The results showed that total organic carbon (TOC) contents varied from 7.25 to 65.54 g kg−1 with a mean of 36.37 ± 17.74 g kg−1. It was found that high TOC concentrations were at lake’s center and low TOC concentrations occurred at the estuary of inflows. Different redox conditions caused by water depth were of the most important factors which might influence TOC contents. Concentrations of HM, HA, and FA in sediments were detected in range of 6.40–58.16 g kg−1, 0.27–3.50 g kg−1, and 0.27–4.26 g kg−1, respectively. Of them, HM was the dominant form and accounted for 74–94% of TOC and 80–90% of humus. Organic Sediment Index (OSI) was used to assess the organics accumulation, and the value of OSI ranged from 0.001 to 0.30, which indicated that Lake Dalinouer was relatively clean. The relative high degree of humidification was found in the eastern of lake, where it should be taken into consideration seriously. Dekun Hou, Jiang He, Changwei Lü, Wei Wang, and Fujin Zhang Copyright © 2014 Dekun Hou et al. All rights reserved.