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...

heteropoly acids (hpa) and their salts have advantages as catalysts which make them both economically and environmentally attractive, strong br?nsted acidity, exhibiting fast reversible multi-electron redox transformations under rather mild conditions, very high solubility in polar solvents, fairly high thermal stability in the solid states, and efficient oxidizing ability, so that they are imp...

abstract cooperative learning refers to small groups of learners working together as a team to solve a problem, complete a task, or accomplish a common goal. in a cooperative environment one’s success is directly related to the success of other members because the focus on the individual shifts towards the group. to test the effectiveness of the method, using jigsaw technique, a study was cond...

abstract the cr(iii) and zn(ii) complexes with 2-((9,10-dihydro-1-hydroxy-9,10-dioxaanthracen-4-yloxy)carbonyl)benzoic acid as ligand have been prepared by reacting cr(no3) and zn(no3)2 and ligand in cloroform. the cr and zn complexes with 2-((9,10-dihydro-1-hydroxy-9,10-dioxaanthracen-4-yloxy)carbonyl) were also prepared in chloroform and aceton solutions. the uv-visible and ft-ir spectra of...

cement is an essential ingredient in the concrete buildings. for production of cement considerable amount of fossil fuel and electrical energy is consumed. on the other hand for generating one tone of portland cement, nearly one ton of carbon dioxide is released. it shows that 7 percent of the total released carbon dioxide in the world relates to the cement industry. considering ecological issu...

‘romanticism’ and ‘romantic’ are among the most controversial terms in literature. most readers, when encountering these words, would think of the well-known period of romanticism of the first three decades of the nineteenth century and the great six english poets known as ‘the big six’ of this period. however, romanticism does not belong to certain artists in a special period; one may seek ele...

the purpose of this study was to investigate the relationship between family functioning and marital adjustment humor couples are due to the nature and objectives of the research and application of methods for its implementation correlation was used. the study population consisted of all the couples in the city who uses random cluster sampling of 200 students were selected as sample. data from ...

the purpose of this study was to investigate how english language teachers in mashhad who teach students in the pre-university cycle perceived the impact of the efltee on their teaching. the target population was nearly all pre-university english language teachers in seven districts of mashhad in the scholastic year 2008/2009. a survey questionnaire which consisted of (36) likert type items, wa...

this thesis deals essentially (but not from all aspects) with the extension of the notion of semigroup compactification and the construction of a general theory of semitopological nonaffine (affine) transformation semigroup compactifications. it determines those compactification which are universal with respect to some algebric or topological properties. as an application of the theory, it is i...

oxidative addition reactions of 1,4-diiodo-butane and 1,3-diiodo-propane with [ptme2(ph2phen)]; in which ph2phen=4,7-diphenyl-1,10-phenanthroline, were studied in different solvents such as acetone and benzene.oxidative addition reaction of [pt me2(ph2phen)] with i(ch2)4i and i(ch2)3i produced the [pt me2i(ch2)4(ph2phen)i] (1a) and [pt me2i(ch2)3(ph2phen)i] (1b).all the platinum (iv) products w...