نتایج جستجو برای: mechanical waves

تعداد نتایج: 346638  

ژورنال: مواد پرانرژی 2020

Cracking is the breaking of bonds in a part of the propellant polymer due to the existing stresses that change the structure of the propellant polymer and they are classified into two general categories: macrocrack and microcrack. The service life of rocket engines is largely a function of the mechanical properties of the solid rocket propellant, the aging characteristics of the rocket propulsi...

Journal: :علوم و تکنولوژی پلیمر 0
مجید حقگو ناصر محمدی مهدی احمدی فرهاد فقیهی معصومه پازوکی

utilizing polymeric materials for damping mechanical waves is of great importance in various fields of applications such as military camouflage, prevention of structural vibrational energy transfer, and noise attenuation. this ability originates from segmental dynamics of chain-like polymer molecules. damping properties of styrene-butadiene rubbercontaining 10 wt% of monosize polystyrene partic...

B Yosefian H Mazdarani M Mokhtari-Diezaji

In spite of wide spread investigations performed,the biological effects of ultrasound waves,specially on DNA molecule has not been fully understood.since any alteration in DNA molecule can lead to chromosome abnormality,the study of clastogenic effects of ultrasound is important.in this study,the effect of 1MHz frequency continuous waves with the power of 0.5,1 and 1.5 watts on G human lymphocy...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده منابع طبیعی 1391

in this study, the effects of oleothermal modification on physical and mechanical peroperties of fir wood (abeis sp.) blocks were examined. at first, some blocks of fir wood with 5 × 20 × 120 cm dimensions were prepared. the blocks were treated in soybean oil. the effects of 3 factors such as treatments temperature (180and 200 °c), holding time (12 and 15 h) and initial moisture content of wood...

One of the new methods for powering low-power electronic devices employed in the sea, is using of mechanical energies of sea waves. In this method, piezoelectric material is employed to convert the mechanical energy of sea waves into electrical energy. The advantage of this method is based on not implementing the battery charging system. Although, many studies have been done about energy harves...

Journal: :Circulation research 1979
W J Paulus V A Claes D L Brutsaert

Isolated cat papillary muscle preparations were assumed to contract in the wall of a hypothetical cylindrical model of the left ventricle ejecting into a vascular impedance. Using analogcomputing techniques, a feedback system was created between shortening, velocity of shortening, and the load on the muscle. This feedback function could be modulated by altering the resistance and capacitance co...

2006
H. Zhang B.-W. Li Z.-M. Sheng Z. Cao G. Hu

– The behavior of spiral turbulence in mechanically deformed excitable media is investigated. Numerical simulations show that when the forcing frequency is chosen around the characteristic frequency of the system, complicated spiral turbulence may be quenched within a shorter evolution time, compared to the case free of mechanical deformation. It is shown that the observed phenomenon occurs due...

Journal: :Applied radiology 2013
Jun Chen Meng Yin Kevin J Glaser Jayant A Talwalkar Richard L Ehman

Many diseases markedly affect the mechanical properties of tissues. This accounts for the efficacy of palpation, a centuries-old technique of clinical medicine. MR Elastography (MRE) is an emerging diagnostic imaging technique for quantitatively assessing the mechanical properties of tissue [1]. It is a three-step process, involving: (i) generating mechanical waves within the tissues of interes...

Journal: :Journal of the Royal Society, Interface 2014
Shigeru Kuroda Itsuki Kunita Yoshimi Tanaka Akio Ishiguro Ryo Kobayashi Toshiyuki Nakagaki

Crawling using muscular waves is observed in many species, including planaria, leeches, nemertea, aplysia, snails, chitons, earthworms and maggots. Contraction or extension waves propagate along the antero-posterior axis of the body as the crawler pushes the ground substratum backward. However, the observation that locomotory waves can be directed forward or backward has attracted much attentio...

Journal: :The Astrophysical Journal 2006

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