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 ...

introduction acetic acid bacteria are large group of obligate aerobic gram negative bacteria with the ability to oxidize ethanol to acetic acid (1). they are widely distributed in natural habitats and classified in family acetobacteraceae. members of this family are useful in industrial production of vinegar(2). acetic acid bacteria (aab) can use substrates as glucose, ethanol, lactate or glyc...

abstract in aggregate, active forms of reactive silica with mineral names are sometimes associated with sand and gravel in concrete mixture. alkali hydroxides originated from alkalis in the cement or other resources form an alkaline silica gel with this reactive silica which becomes swallowed and expanded during time causing damage to concrete. there have been growing researches on alkaline r...

objective: the objective of this study was to investigate the invitro fluoride release of four new self-adhesive resin cements; set (sdi, australia), breeze (pentron, usa), embrace wetbond (pulpdent, usa), g-cem (gc, japan) and to assess the bonding performance of these self-adhesive resin cements for bonding of orthodontic brackets. materials and methods: for fluoride release experiment, six ...

the purpose of this study was to examine the status of supervision on departments’ heads at ferdowsi university of mashhad (fum) and realize some applied themes to provide a fit model for supervising departments’ heads in fum. the method was case study under a research category aimed for applied one. using purposive sampling, interviews were conducted with top fum managers, head departments, an...

acknowledgements i wish to express my gratitude to all those who have helped me in preparing this thesis. i would like to express my deep gratitude to my respected advisor dr. kourosh akef, whose advice and comments helped me in the early stages of the research and throughout the writing process. i would also like to express my gratitude to dr. hajar khanmohammad whose invaluable guidance he...

this research was conducted to examine the effect of a concurrent training on rest level of leptin of plasma and some hormonal factors in non-athlete subjects. the research population included non-athlete men who didn’t participate in any organized sport activities. 30 men were chosen voluntarily among the above-mentioned population and were divided into 2 groups: experimental (15 subjects) an...

abstract over the past two decades, applied linguists and language teachers have shown a great deal of interest in genre-centered approaches , mainly because of pedagogic concerns . this has been due to the need to help non-native readers enhance their ability to understand academic and scientific texts. following swales’ (1981) works on genre analysis, studies of different sections of resear...

abstract this study evaluates the iranian pre-university english textbook in terms of needs, objectives, content, and methodology. the study was designed on the qualitative- quantitative survey basis using interviews and questionnaires, a researcher-made textbook evaluation checklist and a needs analysis questionnaire. the textbook evaluation questionnaire was used in this study to elicit the ...

abstract in this thesis at first we comput the determinant of hankel matrix with enteries a_k (x)=?_(m=0)^k??((2k+2-m)¦(k-m)) x^m ? by using a new operator, ? and by writing and solving differential equation of order two at points x=2 and x=-2 . also we show that this determinant under k-binomial transformation is invariant.