s. mohammad

With the increasing development of concrete structures, properties such as strength and durability of concrete have become particularly important. Therefore, it is necessary to use special concretes and obtain new combinations. Ordinary concrete is brittle and frangible, and if rebar is not used, other materials such as fibers should be added to the mixture to remove the brittleness of the concrete. Fiber is used to control cracks in concrete, which in addition to controlling cracks, improves impact resistance, fatigue, shear, bending, as well as energy absorption of concrete. In this research, fiber concrete made of steel, barchip, and macro synthetic fibers and the combination of each fiber with different volume ratios is subjected to explosive load and the failure rate of each sample and the resistance of fiber concrete with hybrid fibers to explosion have been investigated in laboratory and field. Also, the special electrical resistance of hybrid fiber concrete against the electric current has been evaluated, which can be considered as a measure to evaluate the permeability and parallel absorption of concrete water. The results showed that concrete with macro synthetic fibers had greater explosion resistance than other samples. Also, the electrical resistance of concrete with macro-synthetic fibers has been higher than that of other samples, which will have special applications in corrosive areas with high penetration of chloride ions due to higher electrical resistance and consequently lower permeability. Also, for estimating the cost of fiber performance in concrete, the lowest excess cost of using fibers in concrete was related to the use of 1.5% of the concrete volume of macro synthetic fibers due to the low cost of these fibers and its high resistance to electrical resistance and resistance to explosive load. The use of these fibers in concrete to withstand explosion and electric current has been cost effective.

Multi-cloud environments consist of the considerable variety of resources where the cost of scheduling workflow applications can be significantly reduced in such environments and the resource limitationsimposed by commercial cloud providers can bealso overcome. Accordingly, this study addresses the scheduling of scientific workflowapplications in a multi-cloud environment under a deadline with the aim of minimizing costs. In this paper,an algorithm for scheduling of workflow applications in multi-cloud environment is presented using the cuckoo search algorithm which is one of the most popular meta-heuristic methods. The Cuckoo Search Algorithm is able to search the solution space in a short time and find solutions in the vicinity of the optimal global solution that is close to it. The results show that the proposed approach of this research has better performance in comparison with other meta- heuristic approach in terms of cost reduction. Moreover, the obtained solutions of the proposed meta- heuristic algorithm are in a desirable degree close to the global optimal solutions of mathematical model.

According to the current protocols made by international organizations, the duration of iron supplementation depends on the severity of iron deficiency, ranging from 3 to 6 months in individuals with iron depletion and iron deficiency anemia, respectively. This study was performed to compare 6 and 12 weeks iron supplementations on iron status among a group of non-anemic iron deficient female students. In this quasi-experimental study 53 female students were selected. Students were divided into two groups. Control group were consisted of 30 students who had Hemoglobin level more than 12 ml/dl and serum ferritin level more than 23 ng/dl. Experimental group were 23 non-anemic iron deficient female students with ferritin level less than 23 ng/dl. Experimental group were orally given ferrous fumarate (containing 50 mg iron elemental) daily for three months. Blood samples were collected from experimental group in the beginning, 6 and 12 weeks after the study and for the case group samples were collected in the beginning and at the end of the study and the number of blood cells (CBC), ferritin level and total iron binding capacity (TIBC) were measured. Data were analyzed using Analysis of Covariance and Paired-t tests. Blood hemoglobin and serum ferritin concentrations increased after 6 weeks of supplementation among supplemented group, and were remained almost constant until the 12th week (P>0.001). Changes in serum iron concentrations at the end of study were not statistically different between two groups. Similar trend was observed for TIBC. This study showed that 3-month iron supplementation among iron deficient subjects, as advised by WHO, did not further improve iron status in non anemic iron deficient females compared to 6-weeks daily supplementation of 50 mg elemental Iron. It is obvious that these results cannot be considered to anemic subjects.