نتایج جستجو برای: frequency and time of vibration
تعداد نتایج: 24147133 فیلتر نتایج به سال:
Foam injection is widely applied in amounts of fields to drilling, production, and formation protection. Sometimes, the application result is disappointing, which is caused by the failure of bubble generation in foam flooding. Therefore, it is necessary to seek ways for improving the performance of foam injection. An increased disturbance to the stratum, like the vibration caused by a seismic o...
1. to determine whether difference in birth body mass influenced growth performance in pipistrellus kuhlii we studied a total of 12 captive-born neonates. bats were assigned to two body mass groups: light birth body mass (lbw: 0.89 ± 0.05, n=8) and heavy birth body mass (hbw: 1.35 ± 0.08, n=4). heavier body mass at birth was associated with rapid postnatal growth (body mass and forearm length) ...
structural dynamic parameters: natural period, shape modes and damping ratio of vibration, play a decisive role on the seismic behavior of those structures. there are several methods for determining of the structural dynamic parameters, such as: free vibration, ambient vibration and force vibration tests. in this research the structural response of a three-story building (the natural frequencie...
Hyoscyamus reticulatus is an important medicinal plant belonging to Solanaceae family. This herb has antispasmodic, antichlorogenic and analgesic characteristics due to tropane alkaloids such as hyoscyamine and scopolamine. Mechanical vibration is one of abiotic stresses which could affect on growth and development of plant cells. In this research, effect of high-frequency mechanical vibration ...
abstract: sayyed mohammad tabatabaee is accounted as one of the effective persons in iran contemporaneoushistory and his role in the events of iran constitution revolution is inevitable. sayyed mohammad tabatabaee from the time of naser al din shah qajar and arrival to iran, informed of the advantages and the basis of constitution, was in the thought of making the iran rule as a constituti...
abstract: about 60% of total premium of insurance industry is pertained?to life policies in the world; while the life insurance total premium in iran is less than 6% of total premium in insurance industry in 2008 (sigma, no 3/2009). among the reasons that discourage the life insurance industry is the problem of adverse selection. adverse selection theory describes a situation where the inf...
testing plays a vital role in any language teaching program. it allows teachers and stakeholders, including program administrators, parents, admissions officers and prospective employers to be assured that the learners are progressing according to an accepted standard (douglas, 2010). the problems currently facing language testers have both practical and theoretical implications but the first i...
This paper investigates the coupled axial-radial (CAR) vibration of single-walled carbon nanotubes (SWCNTs) based on doublet mechanics (DM) with a scale parameter. Two coupled forth order partial differential equations that govern the CAR vibration of SWCNTs are derived. It is the first time that DM is used to model the CAR vibration of SWCNTs. To obtain the natural frequency and dynamic respon...
Background and aims: Whole-body vibration is one of the major factors that cause human discomfort and physiological reactions in industrial environments or vehicles. This study aimed in a laboratory environment to investigate the effect of whole body vibration on human discomfort, heart rate and reaction time in men 20 to 30 years old. Methods: 40 Male students i...
Background and Aim: Vibration, especially whole body vibration, is one of the most important physical harmful factors in industrial environments as well as vehicles. Exposure to whole-body vibration can cause different mental and physiological reactions in humans. This study aimed to investigate the effect of exposure to whole body vibration on the mental performances of 20-29 years old males i...
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