Spiral Grooved Vacuum Pump Working in the Coarse Vacuum Region. Improvement in Performance by Means of Grooved Sleeves.

the role of application of dynamic assessment approach in improvement of iranian efl writing performance at different language proficiency levels

the present study sought to investigate the role of dynamic assessment (da) in improvement of iranian efl writing performance at different language proficiency levels. to this end, after conducting the quick placement test, 60 iranian efl learners were assigned to two groups with different language proficiency levels. in both groups each participant wrote two compositions, one before and one af...

Comparative Analysis of Helically Grooved and Circumferentially Grooved Labyrinth Seal

Labyrinth seals are used in turbo-machinery for reducing the leakage of working fluid. The energy lost by the fluid passing through the gap between labyrinth seal and rotor causes the reduction in leakage rate. But the fluid in between the labyrinth seal and rotor induce various forces (radial and tangential forces). These forces can be represented by certain numbers of coefficients, such as st...

Vacuum Gauge to Vacuum Pump Valve

study of cohesive devices in the textbook of english for the students of apsychology by rastegarpour

this study investigates the cohesive devices used in the textbook of english for the students of psychology. the research questions and hypotheses in the present study are based on what frequency and distribution of grammatical and lexical cohesive devices are. then, to answer the questions all grammatical and lexical cohesive devices in reading comprehension passages from 6 units of 21units th...

the u.s. policy in central asia and its impact on the colored revolutions in the region (the case study of tulip revolution in kyrgyzstan)

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