نتایج جستجو برای: Synergistic effect of mixed collectors
تعداد نتایج: 21229619 فیلتر نتایج به سال:
one of the most commonly used techniques to reduce the corrosion rate of rebar in concrete is addition substances named corrosion inhibitors into the concrete. corrosion inhibitor is chemical compounds that were added to concrete to prevent corrosion of steel in concrete. sodium nitrate is a type of anodic inhibitors that this study investigatesthe effect of this inhibitor on the properties of ...
current studies in second language (l2) learning have revealed the positive role of corrective feedback (cf) in both oral and written forms in different language features. the present study was an attempt to investigate the effect of both direct and indirect written corrective feedback (wcf) on the use of grammatical collocations in l2 writing. the study also sought to examine whether the effec...
in this research we have studied the effect of some transition-metals (cu, ag and au) substitutions on two-electron reduction potential of flavins by application of dft method. all geometries have been optimized at blyp level of theory and “6-31+g** + lanl2dz” mixed basis set. the frequency job at the same method and basis sets has been performed to obtain gibbs free energy of compounds. it h...
The present study addresses the direct flotation route for the concentration of a zinc silicate ore. Flotation of hemimorphite faces some challenges due to the similarity of hemimorphite and quartz surface properties. XRD, and XRF analyses, optical mineralogy and SEM with X-ray mapping were performed for characterization. The results showed that the quartz, hemimorphite, calcite and dolomite ar...
we studied the antioxidant activities of the essential oils of zataria multiflora boiss. (zeo) and bunium persicum (boiss.) b. fedtsch (beo) in mixed form on linseed oil using (dpph•), (abts•+), h2o2 scavenging, and reducing power assays. after calculation of ic50 for zeo and beo separately, interactions of the essential oils were investigated at the form of mixture and the results were given...
The contamination of sulfur emanating from pyrrhotite in magnetite concentrates has been a problem in iron ore processing. This study utilized froth flotation to float pyrrhotite away from magnetite using collectors of xanthate and dixanthogen. It was found that xanthate or dixanthogen alone could not achieve selective separation between pyrrhotite and magnetite in flotation. A high loss of mag...
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 aim of this study has been to find answers for the following questions: 1. what is the effect of immediate correction on students pronunciation errors? 2. what would be the effect of teaching the more rgular patterns of english pronunciation? 3. is there any significant difference between the two methods of dealing with pronuciation errore, i. e., correction and the teaching of the regular ...
We studied the antioxidant activities of the essential oils of Zataria multiflora Boiss. (ZEO) and Bunium persicum (Boiss.) B. Fedtsch (BEO) in mixed form on linseed oil using (DPPH•), (ABTS•+), H2O2 scavenging, and reducing power assays. After calculation of IC50 for ZEO and BEO separately, interactions of the essential oils were investigated at the form of mixture and the results were given...
flow in natural river bends is a complex and turbulent phenomenon which affects the scour and sedimentations and causes an irregular bed topography on the bed. for the reason, the flow hydralics and the parameters which affect the flow to be studied and understand. in this study the effect of bed and wall roughness using the software fluent discussed in a sharp 90-degree flume bend with 40.3cm ...
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