نتایج جستجو برای: surface effects

تعداد نتایج: 2109103  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه کاشان - دانشکده علوم انسانی 1389

abstract poor reading comprehension can result in failure in using references, benefiting from professional gatherings and resources, keeping up with the growing body of knowledge in the virtual world of the internet, and failing to achieve in efl programs. the purpose of the present quasi-experimental study was to explore the effects of background knowledge and previewing narrative and expos...

Journal: :journal of nanostructures 2014
o. rahmani m. h. noroozi moghaddam

piezoelectric nanobeams having circular, rectangular and hexagonal cross-sections are synthesized and used in various nano structures; however, piezoelectric nanobeams with hexagonal cross-sections have not been studied in detail. in particular, the physical mechanisms of the surface effect and the role of surface stress, surface elasticity and surface piezoelectricity have not been discussed t...

Due to high surface-to-volume ratio of nanoscale structures, surface stress effects have a significant influence on their behavior. In this paper, a two-dimensional problem for an elastic layer that is bonded to a rigid substrate and subjected to an inclined concentrated line load acting on the surface of the layer is investigated based on Gurtin-Murdoch continuum model to consider surface stre...

Aboutalebi, Shahram, Hosseini, Seyed Ali, Sarhadi, Mohsen,

Objectives: Verbal instructions related to directing the focus of attention to the movement itself or to its effects on or outcomes in the environment affects learning and performing movement skills. The pattern of these effects differs with increase in task difficulty. The goal of this study was to explore the effects of support surface and attention focus on the balance in elderly. Methods...

Behnam Gheshlaghi Jafar Eskandari Jam Yaser Mirzaei,

In this work,The free nonlinear vibrations of nanotubes using the Euler-Bernoulli beam theory along with the von Kármán geometric nonlinearity in presence of surface effects has been investigated. Natural frequencies of a simply-supported nanotube in terms of the Jacobi elliptic functions are obtained by using the free vibration modes of the corresponding linear problem. The numerical results d...

fatemeh zakerhosseini, Kazem Hemmadi

In arid and semi-arid regions, soil surface warming is a considerable phenomenon causing a high thermal gradient which makes water flow intensely. The degree of soil temperature is effective on crop production, plant growth and soil microorganisms. In recent years, the ascending trend of temperature has been substantially noticed by researchers in the issues of pointwise climate change and at w...

Due to high surface-to-volume ratio of nanoscale structures, surface stress effects have a significant influence on their behavior. In this paper, a two-dimensional problem for an elastic layer that is bonded to a rigid substrate and subjected to an inclined concentrated line load acting on the surface of the layer is investigated based on Gurtin-Murdoch continuum model to consider surface stre...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید چمران اهواز - دانشکده مهندسی علوم آب 1393

drought is transient phenomenon , slow , repetitive and integral part of the climate of each region. drought begins with a substantial reduction in precipitation over the long-term average rainfall and over time, reduced soil moisture and surface and ground water resources will continue to decrease. this phenomenon is the most important in bakhtegan basin because of its importance in strategic ...

In this paper surface energy and elastic medium effects on torsional vibrational behavior of nanorods are studied. The surface elasticity theory is used to consider the surface energy effects and the elastic medium is modeled as torsional springs attached to the nanorod. At the next step, Hamilton’s principle is utilized to derive governing equations and boundary conditions. Then, with the aid ...

A. Najafi, H. Sam Daliri

Skidding operations can cause considerable and wide spread soil disturbance. The objective of this study was to evaluate the effects of ground skidding operations on soil compaction, moisture content, and total porosity at different levels of slope and traffic frequency. Four levels of traffic intensity (3, 8, 13, and >13 passes of a Crawler Tractor Onezhets ? 110) and three levels of slope ( ...

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