due to the limiting workspace of parallel manipulator and regarding to finding the trajectory planning of singularity free at workspace is difficult, so finding a best solution that can develop a technique to determine the singularity-free zones in the workspace of parallel manipulators is highly important. in this thesis a simple and new technique are presented to determine the maximal singula...

in this thesis, first the notion of weak mutual associativity (w.m.a.) and the necessary and sufficient condition for a $(l,gamma)$-associated hypersemigroup $(h, ast)$ derived from some family of $lesssim$-preordered semigroups to be a hypergroup, are given. second, by proving the fact that the concrete categories, semihypergroups and hypergroups have not free objects we will introduce t...

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 purpose of the present study was to see which one of the two instruction-processing instruction (pi) and meaningful output based instruction (mobi) accompanied with prompt and recast- is more effective on efl learners’ writing accuracy. in order to homogenize the participants in term of language proficiency a preliminary english test (pet) was administrated between 74 intermediate students ...

abstract the main purpose of this study was to investigate whether there was any significant difference between the speaking achievement of learners who were trained by means of consciousness raising of sociolinguistic skills and that of learners who were trained without the above mentioned task. the participants of this study consist of 60 intermediate level students participating languag...

the subjects of the study are only the tefl teachers and students at gilan university. to obtain the desired data, a questionnaire which was based on the theories and disecussions gathered, was used as the main data gathering instrument. to determine the degree of relationship between variables, covariance and pearson product moment correlation coefficient were the formulas applied. the data we...

بررسی تطبیقی بازده حاصل از کاربرد تحلیل های تکنیکال و روش خرید و نگهداری در بورس اوراق بهادار تهران چکیده در این پژوهش بازدهی حاصل از روش های تجزیه و تحلیل تکنیکی و روش خرید و نگهداری در فرض قابل پیش بینی بودن قیمت ها و عدم وجود شکل ضعیف فرضیه بازار کارا که توسط فاما در سال 791 مطرح گردیده است ، فعالیت میکند . در این مطالعه چهار روش از پر کاربردترین و معتبر ترین روش های تحلیل تکنیکی مورد بر...

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...

determination of uranium in natural water and complex solutions using ion exchange chromatography: a combined procedure using ion exchange chromatography and uv-vis spectrophotometry techniques has been developed to measure uranum in natural water and complex solutions. after conditicing , one hundred milli liters of sample solutions have been passed through an ion exchange column,pachked with ...

abstract part one: the electrode oxidation potentials of a series of eighteen n-hydroxy compounds in aqueous solution were calculated based on a proper thermodynamic cycle. the dft method at the level of b3lyp-6-31g(d,p) was used to calculate the gas-phase free energy differences ,and the polarizable continuum model (pcm) was applied to describe the solvent and its interaction with n-hydroxy ...