Spent catalysts for sulfuric acid production have large amount of vanadium and due to environmental authority it is required to reduce the vanadium contain of the spent catalyst. Experimental investigation was conducted to study the vanadium recovery from spent catalyst via leaching process using sodium hydroxide to study the effect of process variables (temperatures, sodium hydroxide molarities, leaching time and particle size) on vanadium recovery. The effect of process variables (temperature, particle size,molarities of sodium hydroxide and leaching time) on the percentages of vanadium recovery were investigated and discussed .It was found that the percentage of vanadium recovery increased with increasing temperature up to 100 , incre

Massive multiple-input multiple-output (MaMi) systems have attracted much research attention during the last few years. This is because MaMi systems are able to achieve a remarkable improvement in data rate and thus meet the immensely ongoing traffic demands required by the future wireless networks. To date, the downlink training sequence (DTS) for the frequency division duplex (FDD) MaMi communications systems have been designed based on the idealistic assumption of white noise environments. However, it is essential and more practical to consider the colored noise environments when designing an efficient DTS for channel estimation. To this end, this paper proposes a new DTS design by exploring the joint use of spatial channel and n

The increase in the number of trucks and other heavy vehicles in Iraqi highways lead to cracking and deteriorations in the flexible highway. The use of polymermodified asphalt may solve this problem to match the required performance standards. This study investigates the effects of styrene-butadiene-styrene (SBS) polymer on the performance behaviour of Iraqi bitumen binder. The characteristics of bitumen binder were analysed to observe the compatibility of bitumen with SBS polymer. The bitumen binder was mixed with three different contents of SBS (4%, 4.5%, and 5%) by weight of asphalt cement. Viscosity tests were conducted on the SBS polymer-modified asphalt at 135 oC and 165 oC in addition to conventional binder tests. The prepar

This research is dedicated to study Al-Ra’ee Al-Numayri, a distinctive poetic character, to find out the most important (artistic) pre-Islamic features that contributed to its formation. It is further dedicated to know the influence of these features on his literature in the literary arena. After surveying his poetic texts and reading them according to the analytical and investigative methods, the art of the researcher was limited to the  field of  traditionalists. He was following the footsteps of the ancients by adhering to the traditional Arabic poetry style and the traditional poetic image. Despite that, he had his own imprints and  unique style of interrogating times and places with its people, animals and plants. H

Hydrocarbon production might cause changes in dynamic reservoir properties. Thus the consideration of the mechanical stability of a formation under different conditions of drilling or production is a very important issue, and basic mechanical properties of the formation should be determined.
There is considerable evidence, gathered from laboratory measurements in the field of Rock Mechanics, showing a good correlation between intrinsic rock strength and the dynamic elastic constant determined from sonic-velocity and density measurements.
The values of the mechanical properties determined from log data, such as the dynamic elastic constants derived from the measurement of the elastic wave velocities in the material, should be more a

Straight tendons in pretensioned members can cause high-tensile stresses in the concrete extreme fibers at end sections because of the absence of the bending stresses due to self-weight and superimposed loads and the dominance of the moment due to prestressing force alone. Accordingly, the concrete tensile stresses at the ends of a member prestressed with straight tendons may limit the service load capacity of the member. It is therefore important to establish limiting zone in the concrete section within which the prestressing force can be applied without causing tension in the extreme concrete fibers. Two practical methods are available to reduce the stresses at the end sections due to the prestressing force. The first method based