نتایج جستجو برای: non linear vibration

تعداد نتایج: 1746146  

Journal: :تحقیقات نظام سلامت 0
اصغر نیک روش استادیار، گروه مهندسی بهداشت حرفه ای، دانشگاه علوم پزشکی شیراز، شیراز، ایران زهرا زمانیان دانشجوی کارشناسی ارشد ارگونومی، گروه ارگونومی، دانشگاه علوم پزشکی شیراز، شیراز، ایران مجتبی خدادادی مربی، گروه روانشناسی، دانشگاه امام حسین(ع)، تهران، ایران محمدرضا منظم دانشیار، گروه مهندسی بهداشت حرفه ای، دانشگاه علوم پزشکی تهران، تهران، ایران جعفر حسن زاده دانشیار، گروه اپیدمیولوژی، دانشگاه علوم پزشکی شیراز، شیراز، ایران

background: deficiency of attention and concentration is one of great reasons of traffic incidents and it covers between 20 to 50 percent of events due to careless and mindedness. studies show that attention and concentration are considered as one of important cognitive components in safe driving. vibration is an important physical effect in all vehicles. till now has not been any organized stu...

Journal: :journal of nanostructures 2012
t. hosseinabad g. nabiyouni k. hedayati

co-fe films were electrodeposited on cu substrate from electrolytes with different co concentration  levels. x-ray diffraction (xrd) was used  to  investigate  the  films  crystal  structures. the  results  indicate that  if  the  co  concentration  is  less  that  the  fe  concentration,  the cubic  structure  appears  in  the  films, while  the  hexagonal  structure dominates when  the co  co...

2008
Andrew J. Fleming Adrian G. Wills

Periodic scanning trajectories are designed with minimal harmonic content and fixed linear regions. While minimum harmonic content reduces vibration in mechanical scanners, fixed linear regions eliminate curvature in the scan area. Simulated and experimental results demonstrate less induced vibration than presently used techniques.

Journal: :international journal of nano dimension 0
m. h. shojaeefard school of automotive engineering, iran university of science and technology, tehran, iran a. khalkhali school of automotive engineering, iran university of science and technology, tehran, iran s.h. khakshournia school of automotive engineering, iran university of science and technology, tehran, iran f. malmir school of automotive engineering, iran university of science and technology, tehran, iran

this paper investigates the effect of different methods of carbon nanotubes distribution in a thin matrix on static and dynamic behavior of the nanocomposite. five different symmetric patterns of distribution are considered, including four parabolic patterns and a linear one. for each pattern, the effective mechanical properties of the resultant nanocomposite are calculated using the rule of mi...

2016
Fumiya Kitayama Katsuhiro Hirata Noboru Niguchi Masashi Kobayashi

Nowadays, electromagnetic linear oscillatory actuators are used as vibration control devices because of their high controllability. However, there is a problem that thrust and vibration are small at a wide drive frequency range. In order to improve this problem, we propose a new linear oscillatory actuator that can easily change its own characteristics by using two sets of coils. Through finite...

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In this study, the effects of vibration training on physical fitness factors in elderly females investigated. 40 subjects with age 61/09±6/24 yrs, weight 65/84±11/98 kg, height 156/99±5/06 cm and body mass index 26/64±4/23 kg/m2 voluntary participated in this study and were divided in vibration (n=16), non-vibration (n=14) and control (n=10) groups. The vibration group performed exercises o...

2014
R. Lal

Abstract—The effect of non-homogeneity on the free transverse vibration of thin rectangular plates of bilinearly varying thickness has been analyzed using generalized differential quadrature (GDQ) method. The non-homogeneity of the plate material is assumed to arise due to linear variations in Young’s modulus and density of the plate material with the in-plane coordinates x and y . Numerical re...

2009
Vladan Panković

In this work a classical linear harmonic oscillator, evolving during a small time interval (so that simple non-linear, second order Taylor approximation of the dynamics is satisfied) and restarting (by a mechanism) in a strictly chosen series of the time moments, is considered. It is shown that given linear oscillator behaves dynamically analogously to discrete logistic equation, which, as an e...

Journal: :journal of medical signals and sensors 0
yoones imani niloufar teyfouri mohammad reza ahmadzadeh marzieh golabbakhsh

motion analysis and quality assessment of human sperm cell is of great importance for clinical applications of male infertility. sperm tracking is quite complex due to cell collision, occlusion and missed detection. the goal of this study is simultaneous tracking of multiple human sperm cells. in the first step in this research the frame difference algorithm is used for background subtraction. ...

Journal: :iranian journal of applied animal science 2015
a.o. raji l.g. asheikh i.d. mohammed

this study compared the use of five different models to describe the growth from birth to 20 weeks of age of kids from both genders of nondescript goats. fifty nine (59) nondescript kids were weighed weekly at the university of maiduguri livestock teaching and research farm, nigeria and the live weights were modeled. biologically relevant variables were estimated for each kid from the logistic,...

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