a semi-empirical mathematical model for predicting physical part of ignition delay period in the combustion of direct - injection diesel engines with swirl is developed . this model based on a single droplet evaporation model . the governing equations , namely , equations of droplet motion , heat and mass transfer were solved simultaneously using a rung-kutta step by step unmerical method . the...

fluorescence chemical sensors for the highly sensitive and selective determination of pb2+ , hg2+, co2+ and fe3+ ions in aqueous solutions are described. the ion sensing system was prepared by incorporating lipophilic ligand (l) as a neutral ion-selective fluoroionophore in the plasticized pvc membrane containing sodium tetraphenylborate or potasium tetrakis (p-chlorophenyl) borate as a liphoph...

in the present work, a simple and sensitive method was developed for determination of morphine and heroin using gold nanoparticles as resonance rayleigh scattering (rrs) and colorimetric technique’s probe. synthesized gold nanoparticles by sodium citrate reduction method have a negative charge layer on their surfaces because of self-assembled citrate anions on their surface. binding of morphin...

this study investigated how group formation method, namely student-selected vs. teacher-assigned, influences the results of the community model of teaching creative writing; i.e., group dynamics and group outcome (the quality of performance). the study adopted an experimental comparison group and microgenetic research design to observe the change process over a relatively short period of time. ...

در این تحقیق، تنوع ژنتیکی جمعیت آرتمیا اورمیانا و آرتمیا فرانسیسکانا ی موجود در ایران با استفاده از 5 جفت آغازگر ریزماهواره ای (af-b105tail، af-a136، apdq03tail، apdq04tail و apdq05tail) ویژه ی آرتمیا فرانسیسکانا و آرتمیا پارتنوژنتیکا بررسی شد. از 50 سیست آرتمیا ی هر یک از این دو جمعیت به صورت انفرادی dna با روش گلوله ی داغ استخراج شد. با استفاده از آغازگر ها ی پنج گانه و از طریق واکنش زنجیره ا...

data envelopment analysis (dea) is a powerful tool for measuring relative efficiency of organizational units referred to as decision making units (dmus). in most cases dmus have network structures with internal linking activities. traditional dea models, however, consider dmus as black boxes with no regard to their linking activities and therefore do not provide decision makers with the reasons...

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 ...

according to research, academic self-concept and academic achievement are mutually interdependent. in the present study, the aim was to determine the relationship between the academic self-concept and the academic achievement of students in english as a foreign language and general subjects. the participants were 320 students studying in 4th grade of high school in three cities of noor, nowshah...

in iran we already use laminate tubes only in cosmetics industry. laminate tube manufacturers via using the most modern technology of the world, faced with the laminate tube market being saturated in cosmetics industry for packaging the cosmetic creams and toothpaste. but considering the great food market and therefore laminate tube features such as beautiful packaging, ease of use for the fina...

in current study, 63 samples of bat populations collected from differ regions were used for evaluating the geographic variations. twenty cranial and dental characters for traditional morphometric and landmarks method on the ventral, dorsal skull and mandible for geometry morphometric studies were used. statistical analyses of traditional morphometric and geometry morphometric data indicated low...