in this work, a novel and fast method for direct analysis of volatile compounds (davc) of medicinal plants has been developed by holding a filament from different parts of a plant in the gc injection port. the extraction and analysis of volatile components of a small amount of plant were carried out in one-step without any sample preparation. after optimization of temperature, extraction time a...

the aim of this paper is eliminating cr(vi) by natural hap. hap is a inexpensive material which is used from bovine critical bone ash in order to remove heavy metal ions like cr(vi). some experiments in different ph are performed (ph=2,3,7). maximum adsorption was appeared at ph=2, dosage=0.3 gr, c0=10 mg/l. cr(vi) removal depends on ph value and initial amount of cr(vi) result of experiments w...

in this thesis, a better reaction conditions for the synthesis of spirobarbiturates catalyzed by task-specific ionic liquid (2-hydroxy-n-(2-hydroxyethyl)-n,n-dimethylethanaminium formate), calcium hypochlorite ca(ocl)2 or n-bromosuccinimide (nbs) in the presence of water at room temperature by ultrasonic technique is provided. the design and synthesis of spirocycles is a challenging task becaus...

a novel acrylic acid-functionalized fe3o4 magnetic nanoparticle with a core-shell structure was developed for utilization as a heterogeneous organosuperacid in chemical transformations. the structural, surface, and magnetic characteristics of the nanosized catalyst were investigated by various techniques such as transmission electron microscopy (tem), thermogravimetric analysis (tga), and ft-ir...

the present research study attempted to find out the extent to which two pre-task activities of “glossary of unknown vocabulary items” and “content related support” assisted efl language learners with their performance on listening comprehension questions across two different proficiency levels (low and high). data for this study were obtained from a total of 120 language learners, female and m...

some new water-soluble schiff base complexes of na2[m(5-so3-1,2-salophen)].nh2o; (5-so3-1,2-salophen = n,n’-bis(5-sulphosalicyliden)-1,2-phenylendiamine); na2[m(5-so3-2,3-salpyr)(h2o)n].2h2o; (5-so3-2,3-salpyr = n,n’-bis(5-sulphosalicyliden)-2,3-diaminopyridine); and na2[m(5-so3-3,4-salbenz)(h2o)n].nh2o; (5-so3-3,4-salbenz = n,n’-bis(5-sulphosalicyliden)-3,4-diaminobenzophenon); where m = cu, n...

over the past decades a number of approaches have been applied for forecasting mortality. in 1992, a new method for long-run forecast of the level and age pattern of mortality was published by lee and carter. this method was welcomed by many authors so it was extended through a wider class of generalized, parametric and nonlinear model. this model represents one of the most influential recent d...

the purpose of this thesis was to investigate how differently metacognitive, cognitive, and social/affective strategies affect l2 learners’ reading comprehension. to this end, the study employed a quasi-experimental design with a placement test as a proficiency test to find the homogeneity of groups. three classes were randomly selected as the experimental groups (n =90), and each class was tau...